Search for Abstracts using Keywords

51,427 Abstracts & Growing Daily. Sourced from the US National Library of Medicine.

201
[+]

Pomegranate has potent anti-aromatase activity warranting its use for human breast cancer.


Fresh organically grown pomegranates (Punica granatum L.) of the Wonderful cultivar were processed into three components: fermented juice, aqueous pericarp extract and cold-pressed or supercritical CO2-extracted seed oil. Exposure to additional solvents yielded polyphenol-rich fractions ('polyphenols') from each of the three components. Their actions, and of the crude whole oil and crude fermented and unfermented juice concentrate, were assessed in vitro for possible chemopreventive or adjuvant therapeutic potential in human breast cancer. The ability to effect a blockade of endogenous active estrogen biosynthesis was shown by polyphenols from fermented juice, pericarp, and oil, which inhibited aromatase activity by 60-80%. Fermented juice and pericarp polyphenols, and whole seed oil, inhibited 17-beta-hydroxysteroid dehydrogenase Type 1 from 34 to 79%, at concentrations ranging from 100 to 1,000 microg/ml according to seed oil >> fermented juice polyphenols > pericarp polyphenols. In a yeast estrogen screen (YES) lyophilized fresh pomegranate juice effected a 55% inhibition of the estrogenic activity of 17-beta-estradiol; whereas the lyophilized juice by itself displayed only minimal estrogenic action. Inhibition of cell lines by fermented juice and pericarp polyphenols was according to estrogen-dependent (MCF-7) >> estrogen-independent (MB-MDA-231) > normal human breast epithelial cells (MCF-10A). In both MCF-7 and MB-MDA-231 cells, fermented pomegranate juice polyphenols consistently showed about twice the anti-proliferative effect as fresh pomegranate juice polyphenols. Pomegranate seed oil effected 90% inhibition of proliferation of MCF-7 at 100 microg/ml medium, 75% inhibition of invasion of MCF-7 across a Matrigel membrane at 10 microg/ml, and 54% apoptosis in MDA-MB-435 estrogen receptor negative metastatic human breast cancer cells at 50 microg/ml. In a murine mammary gland organ culture, fermented juice polyphenols effected 47% inhibition of cancerous lesion formation induced by the carcinogen 7,12-dimethylbenz[a]anthracene (DMBA). The findings suggest that clinical trials to further assess chemopreventive and adjuvant therapeutic applications of pomegranate in human breast cancer may be warranted.

Breast Cancer Res Treat. 2002 Feb;71(3):203-17. PMID: 12002340

202
[+]

Resveratrol demonstrates potent antifungal activity against Candida Albicans.


Resveratrol (3,5,4'-trihydroxystilbene) is a naturally occurring, multi-biofunctional chemical existing in grapes and various other plants as a polyphenol type, and it is one of the best known natural anticancer and antiatherosclerosis reagents. In this study, we investigated the antifungal action by resveratrol in Candida albicans, which is a human infectious fungi as an agent of candidiasis. Resveratrol displayed potent fungicidal activity in an energy-dependent manner, without any hemolytic effects against human erythrocytes. It was found that the serum-induced mycelial forms, which play a crucial role in the pathogenesis of C. albicans during host tissue invasion, were disrupted by resveratrol. To understand the correlation between lethal effects and resveratrol action, we examined the physiological changes of C. albicans. A significant accumulation of intracellular trehalose was induced by stress responses to resveratrol action, and a remarkable arrest of cell-cycle processes at the S-phase in C. albicans occured. Therefore, the fungicidal effects of resveratrol demonstrate that this compound is a potential candidate as an antifungal agent in treating infectious diseases by candidal infections.

J Microbiol Biotechnol. 2007 Aug;17(8):1324-9. PMID: 18051601

203
[+]

Chinese Plum (Prunus salicina) may inhibit the development of breast cancer.


The goal of this study was to evaluate the anticancer effect of Prunus salicina Lindl. cv. Soldam at three maturity stages (immature, midmature and mature stages). Previous studies have shown that this fruit (plums) possesses hematopoiesis effects, prevents osteoporosis and has anti-mutagenic effects. An acetone extract of immature P. salicina Lindl. cv. Soldam fruit contained higher levels of total phenolics and condensed tannins than midmature and mature plums. The results showed that an acetone extract of immature plums possesses cytotoxic effects, which are related to the activity of the total polyphenols in the fruits. Apoptosis in MDA-MB-231 cells mediated by the immature plums was associated with an increase in Bax levels and a reduction in Bcl-2 levels and the cleavage of caspase 3, caspase 7, caspase 9 and poly-(ADP-ribose) polymerase. These results indicate that immature fruit of P . salicina Lindl. cv. Soldam can be regarded as a safe and promising new dietary source for decreasing the risk of developing breast cancer.

Int J Food Sci Nutr. 2007 Feb;58(1):42-53. PMID: 17415955

204
[+]

EGCG has a direct effect on growth inhibition in human esophageal cancer.


"(-)-Epigallocatechin-3-gallate (EGCG), the principal polyphenol in green tea, has been shown to inhibit the growth of many cancer cell lines and to suppress the phosphorylation of epidermal growth factor receptor (EGFR). We observed similar effects of EGCG in esophageal squamous cell carcinoma KYSE 150 cells and epidermoid squamous cell carcinoma A431 cells. Pretreatment of KYSE 150 cells with EGCG (20 micromol/L) for 0.5 to 24 hours in HAM's F12 and RPMI 1640 mixed medium at 37 degrees C, before the addition of EGF, resulted in a decreased level of phosphorylated EGFR (by 32-85%). Prolonged treatment with EGCG (8 or 24 hours) also decreased EGFR protein level (both by 80%). EGCG treatment for 24 hours also caused decreased signals of HER-2/neu in esophageal adenocarcinoma OE19 cells. These effects of EGCG were prevented or diminished by the addition of superoxide dismutase (SOD, 5 units/mL), or SOD plus catalase (30 units/mL), to the cell culture medium. A similar phenomenon on inactivation of EGFR was observed in A431 cells as well. Under culture conditions for KYSE 150 cells, EGCG was unstable, with a half-life of approximately 30 minutes; EGCG dimers and other oxidative products were formed. The presence of SOD in the culture medium stabilized EGCG and increased its half-life to longer than 24 hours and some EGCG epimerized to (+)-gallocatechin-3-gallate. A mechanism of superoxide radical-mediated dimerization of EGCG and H2O2 formation is proposed. The stabilization of EGCG by SOD in the culture medium potentiated the activity of EGCG in inhibiting KYSE 150 cell growth. The results suggest that in cell culture conditions, the auto-oxidation of EGCG leads to EGFR inactivation, but the inhibition of cell growth is due to other mechanisms. It remains to be determined whether the presently observed auto-oxidation of EGCG occurs in vivo. In future studies of EGCG and other polyphenolic compounds in cell culture, SOD may be added to stabilize EGCG and to avoid possible artifacts.

Cancer Res. 2005 Sep 1;65(17):8049-56. PMID: 16140980

205
[+]

Green tea inhibits lung carcinogenesis.


In order to study the biological activities of tea preparations and purified tea polyphenols, their growth inhibitory effects were investigated using four human cancer cell lines. Growth inhibition was measured by [3H]thymidine incorporation after 48 h of treatment. The green tea catechins (-)-epigallocatechin-3-gallate (EGCG) and (-)-epigallocatechin (EGC) displayed strong growth inhibitory effects against lung tumor cell lines H661 and H1299, with estimated IC50 values of 22 microM, but were less effective against lung cancer cell line H441 and colon cancer cell line HT-29 with IC50 values 2- to 3-fold higher. (-)-Epicatechin-3-gallate, had lower activities, and (-)-epicatechin was even less effective. Preparations of green tea polyphenols and theaflavins had higher activities than extracts of green tea and decaffeinated green tea. The results suggest that the growth inhibitory activity of tea extracts is caused by the activities of different tea polyphenols. Exposure of H661 cells to 30 microM EGCG, EGC or theaflavins for 24 h led to the induction of apoptosis as determined by an annexin V apoptosis assay, showing apoptosis indices of 23, 26 and 8%, respectively; with 100 microM of these compounds, the apoptosis indices were 82, 76 and 78%, respectively. Incubation of H661 cells with EGCG also induced a dose-dependent formation of H2O2. Addition of H2O2 to H661 cells caused apoptosis in a manner similar to that caused by EGCG. The EGCG-induced apoptosis in H661 cells was completely inhibited by exogenously added catalase (50 units/ml). These results suggest that tea polyphenol-induced production of H2O2 may mediate apoptosis and that this may contribute to the growth inhibitory activities of tea polyphenols in vitro..  

Carcinogenesis. 1998 Apr;19(4):611-6. PMID: 9600345

206
[+]

EGCG induces apoptosis in melanoma cells.


Melanoma accounts for only about 4% of all skin cancer cases but most of not been adequately effective in the management of melanoma. Therefore, novel approaches are needed for prevention and treatment of this disease. Chemoprevention by naturally occurring agents present in food and beverages has shown benefits in certain cancers including nonmelanoma skin cancers. Here, employing 2 human melanoma cell lines (A-375 amelanotic malignant melanoma and Hs-294T metastatic melanoma) and normal human epidermal melanocytes (NHEM), we studied the antiproliferative effects of epigallocatechin-3-gallate (EGCG), the major polyphenolic antioxidant present in green tea. EGCG treatment was found to result in a dose-dependent decrease in the viability and growth of both melanoma cell lines. Interestingly, at similar EGCG concentrations, the normal melanocytes were not affected. EGCG treatment of the melanoma cell lines resulted in decreased cell proliferation (as assessed by Ki-67 and PCNA protein levels) and induction of apoptosis (as assessed cleavage of PARP, TUNEL assay and JC-1 assay). EGCG also significantly inhibited the colony formation ability of the melanoma cells studied. EGCG treatment of melanoma cells resulted in a downmodulation of anti-apoptotic protein Bcl2, upregulation of proapoptotic Bax and activation of caspases -3, -7 and -9. Furthermore, our data demonstrated that EGCG treatment resulted in a significant, dose-dependent decrease in cyclin D1 and cdk2 protein levels and induction of cyclin kinase inhibitors (ckis) p16INK4a, p21WAF1/CIP1 and p27KIP1. Our data suggest that EGCG causes significant induction of cell cycle arrest and apoptosis of melanoma cells that is mediated via modulations in the cki-cyclin-cdk network and Bcl2 family proteins. Thus, EGCG, alone or in conjunction with current therapies, could be useful for the management of melanoma.

Int J Cancer. 2005 Apr 20;114(4):513-21. PMID: 15609335

207
[+]

Ellagic acid demonstrates anticancer activity against human neuroblastoma cells.


Ellagic acid, a polyphenolic compound found in berries, fruits and nuts, has been shown to possess growth-inhibiting and apoptosis promoting activities in cancer cell lines in vitro. The objective of this study was to investigate the effect of ellagic acid in human neuroblastoma SH-SY5Y cells. In cultures of SH-SY5Y cells incubated with ellagic acid, time- and concentration-dependent inhibitory effects on cell number were demonstrated. Ellagic acid induced cell detachment, decreased cell viability and induced apoptosis as measured by DNA strand breaks. Ellagic acid-induced alterations in cell cycle were also observed. Simultaneous treatment with all-trans retinoic acid did not rescue the cells from ellagic acid effects. Furthermore, the results suggested that pre-treatment with all-trans retinoic acid to induce differentiation and cell cycle arrest did not rescue the cells from ellagic acid-induced cell death.

Biomed Pharmacother. 2008 Sep 15. PMID: 18848760

208
[+]

Cranberry polyphenols sensitize platinum-resistant ovarian cancer cells to the cytotoxic effects of paraplatin.


Polyphenolic extracts of the principal flavonoid classes present in cranberry were screened in vitro for cytotoxicity against solid tumor cells lines, identifying two fractions composed principally of proanthocyanidins (PACs) with potential anticancer activity. Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF-MS) analysis of the proanthocyanidins (PACs) fractions indicated the presence of A-type PACs with 1-4 linkages containing between 2-8 epicatechin units with a maximum of 1 epigallocatechin unit. PACs exhibited in vitro cytotoxicity against platinum-resistant human ovarian, neuroblastoma and prostate cancer cell lines (IC(50) = 79-479 microg/mL) but were non-cytotoxic to lung fibroblast cells (IC(50) > 1000 microg/ml). SKOV-3 ovarian cancer cells treated with PACs exhibited classic apoptotic changes. PACs acted synergistically with paraplatin in SKOV-3 cells. Pretreatment of SKOV-3 cells with PACs (106 microg/ml) resulted in a significant reduction of the paraplatin IC(50) value. Similarly, in a BrdU incorporation assay, co-treatment of SKOV-3 cells with PACs and paraplatin revealed reduced cell proliferation at lower concentrations than with either individually. In SKOV-3 cell cultures co-treated with PAC-1 and paraplatin, an HPLC analysis indicated differential quantitative presence of various PAC oligomers such as DP-8, -9, -11 and -14 indicating either selective binding or uptake. Cranberry proanthocyanidins exhibit cell-line specific cytotoxicity, induce apoptotic markers and augment cytotoxicity of paraplatin in platinum-resistant SKOV-3 ovarian cancer cells. Copyright (c) 2009 John Wiley & Sons, Ltd.

Phytother Res. 2009 Jan 26. PMID: 19172579

209
[+]

EGCG, a green tea polyphenol, has a multitude of therapeutic benefits in the prevention and treatment of prostate cancer.


Prostate cancer (PCa) is the most frequently diagnosed malignancy and the second leading cause of cancer-related deaths in American males. For these reasons, it is necessary to intensify our efforts for better understanding and development of novel treatment and chemopreventive approaches for this disease. In recent years, green tea has gained considerable attention as an agent that could reduce the risk of several cancer types. The cancer-chemopreventive effects of green tea appear to be mediated by the polyphenolic constituents present therein. Based on geographical observations that suggest that the incidence of PCa is lower in Japanese and Chinese populations that consume green tea on a regular basis, we hypothesized that green tea and/or its constituents could be effective for chemoprevention of PCa. To investigate this hypothesis, we initiated a program for the chemoprevention of PCa by green tea. In cell-culture systems that employ human PCa cells DU145 (androgen insensitive) and LNCaP (androgen sensitive), we found that the major polyphenolic constituent (-)-epigallocatechin-3-gallate (EGCG) of green tea induces 1) apoptosis, 2) cell-growth inhibition, and 3) cyclin kinase inhibitor WAF-1/p21-mediated cell-cycle dysregulation. More recently, using a cDNA microarray, we found that EGCG treatment of LNCaP cells results in 1) induction of genes that functionally exhibit growth-inhibitory effects, and 2) repression of genes that belong to the G-protein signaling network. In animal studies that employ a transgenic adenocarcinoma of the mouse prostate (TRAMP), which is a model that mimics progressive forms of human prostatic disease, we observed that oral infusion of a polyphenolic fraction isolated from green tea (GTP) at a human achievable dose (equivalent to 6 cups of green tea/d) significantly inhibits PCa development and metastasis. We extended these studies and more recently observed increased expression of genes related to angiogenesis such as vascular endothelial growth factor (VEGF) and those related to metastasis such as matrix metalloproteinases (MMP)-2 and MMP-9 in prostate cancer of TRAMP mice. Oral feeding of GTP as the sole source of drinking fluid to TRAMP mice results in significant inhibition of VEGF, MMP-2 and MMP-9. These data suggest that there are multiple targets for PCa chemoprevention by green tea and highlight the need for further studies to identify novel pathways that may be modulated by green tea or its polyphenolic constituents that could be further exploited for prevention and/or treatment of PCa.  

J Nutr. 2003 Jul;133(7 Suppl):2417S-2424S. PMID: 12840218

210
[+]

EGCG, a green tea polyphenol, encourages programmed cell death in prostate cancer cells.


Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL/Apo2L) is a promising candidate for cancer therapy, however, emergence of drug resistance limits its potential use. Here, we report for the first time that epigallocatechin-3-gallate (EGCG), the major polyphenolic constituent of green tea, sensitizes TRAIL-resistant LNCaP cells to TRAIL-mediated apoptosis through modulation of intrinsic and extrinsic apoptotic pathways. When combined with EGCG, Apo2L/TRAIL exhibited enhanced apoptotic activity in LNCaP cells characterized by three major molecular events. First, apoptosis induction was accompanied by the upregulation of poly(ADP-ribose) polymerase cleavage and modulation of pro- and antiapoptotic Bcl2 family of proteins. A synergistic inhibition of inhibitors of apoptosis with concomitant increase in caspase cleavage was observed. Second, pretreatment of cells with EGCG resulted in modulation of death-inducing signaling cascade complex involving DR4/TRAIL R1, Fas-associated death domain and FLICE-inhibitory protein proteins. Last, we observed a synergistic inhibition in the invasion and migration of LNCaP cells. This effect was observed to be mediated through inhibition in the protein expression of vascular endothelial growth factor, uPA and angiopoietin 1 and 2. Further, the activity and protein expression of MMP-2, -3 and -9 and upregulation of TIMP1 in cells treated with a combination of EGCG and TRAIL was observed. These data might have implications for developing new strategies aimed at eliminating prostate cancer cells resistant to TRAIL.  

Oncogene. 2008 Mar 27;27(14):2055-63. Epub 2007 Nov 12. PMID: 17998943

211
[+]

Wheat grass extract induces programmed cell death in colon cancer cell lines.


Wheat sprouts contain a very high level of organic phosphates and a powerful cocktail of different molecules such as enzymes, reducing glycosides and polyphenols. The antioxidant properties of wheat sprouts have been widely documented and it has been shown that they are able to protect DNA against free-radicals mediated oxidative damage. Furthermore, we have recently reported on the effects of several polyphenols on 20S proteasomes, underlying the dual role of epigallocatechin-3-gallate as an antioxidant and a proteasome effector in cancer cells. The aim of this study was to investigate the effects of wheat sprout extracts on 20S proteasome functionality. Wheat sprout extracts have been analysed and characterized for their polyphenolic content using the Folin-Ciocalteau reagent and RP-HPLC technique. Comparing our data with a polyphenol standard mixture we identified five different polyphenols: gallic acid, epigallocatechin-3-gallate, epigallocatechin, epicatechin and catechin. The treatment of isolated 20S proteasomes with the extract induced a gradual inhibition of all the tested components, ChT-L, T-L, PGPH and BrAAP, in both the complexes. At low extract concentration a slight activation of the enzyme was evident only for the BrAAP component of the constitutive enzyme and the ChT-L activity of the immunoproteasome. beta-casein degradation rate decreased, particularly with the immunoproteasome. Human Colon adenocarcinoma (Caco) cells, stimulated with 12-O-tetradecanoylphorbol-13-acetate, showed activation of the 20S proteasome activities at short incubation times and an increase in intracellular oxidative proteins. Cells treatment with wheat sprout extract led to proteasome inhibition in unstimulated cells and attenuated the effects mediated by TPA. Finally, exposure to the extract affected the expression levels of pro-apoptotic proteins.

Biochimie. 2008 May;90(5):790-801. Epub 2007 Dec 23. PMID: 18190797

212
[+]

Resveratrol is a bilevel inhibitor of aromatase in breast cancer cells.


Estrogen plays a crucial role in the development of breast cancer, and the inhibition of estrogen synthesis has been an important target for the prevention and treatment of this disease. The rate-limiting reaction of the hormone biosynthesis is catalyzed by cytochrome P450 (CYP) 19 enzyme or aromatase. It has been of genuine interest to uncover an aromatase-inhibitory compound from a dietary source. Resveratrol is a polyphenolic compound that can be isolated from grape peel. Because of its structural resemblance to estrogen, resveratrol's agonistic and antagonistic properties on estrogen receptor have been examined and demonstrated. In the present study, the effect of resveratrol on the expression and enzyme activity of aromatase was investigated. By assaying on MCF-7 cells stably transfected with CYP19 (MCF-7aro cells), resveratrol inhibited the aromatase activity with an IC(50) value of 25 microM. Kinetic analysis indicated that both competitive and noncompetitive inhibition might be involved. The administration of 10 nmol/l testosterone-a substrate of aromatase-produced a 50% increase in the MCF-7aro cell number. This cell proliferation specifically induced by testosterone was significantly reduced by 10 microM resveratrol. In addition, 50 microM resveratrol significantly reduced the CYP19-encoding mRNA abundance in SK-BR-3 cells. The transcriptional control of CYP19 gene is tissue specific, and promoter regions I.3 and II have previously been shown to be responsible for CYP19 expression in breast cancer cells. Luciferase reporter gene assays revealed that resveratrol could repress the transcriptional control dictated by the promoter regulation. The present study illustrated that pharmacological dosage of resveratrol inhibited aromatase at both the enzyme and mRNA levels.

Toxicol Sci. 2006 Jul;92(1):71-7. Epub 2006 Apr 11. PMID: 16611627

213
[+]

Artichoke extract exhibits antioxidant and apoptotic activity relevant to the treatment of human liver cancer.


Cultured rat hepatocytes and human hepatoma HepG2 cells were used to evaluate the hepatoprotective properties of polyphenolic extracts from the edible part of artichoke (AE). The hepatocytes were exposed to H2O2generated in situ by glucose oxidase and were treated with either AE, or pure chlorogenic acid (ChA) or with the well known antioxidant, N, N'-diphenyl-p-phenilenediamine (DPPD). Addition of glucose oxidase to the culture medium caused depletion of intracellular glutathione (GSH) content, accumulation of malondialdehyde (MDA) in the cultures, as a lipid peroxidation indicator, and cell death. These results demonstrated that AE protected cells from the oxidative stress caused by glucose oxidase, comparable to DPPD. Furthermore, AE, as well as ChA, prevented the loss of total GSH and the accumulation of MDA. Treatment of HepG2 cells for 24 h with AE reduced cell viability in a dose-dependent manner, however, ChA had no prominent effects on the cell death rate. Similarly, AE rather than ChA induced apoptosis, measured by flow cytometric analysis of annexin and by activation of caspase-3, in HepG2 cells. Our findings indicate that AE had a marked antioxidative potential that protects hepatocytes from an oxidative stress. Furthermore, AE reduced cell viability and had an apoptotic activity on a human liver cancer cell line.

Nutr Cancer. 2008;60(2):276-83. PMID: 18444161

214
[+]

Litchi fruit extract exhibits anticancer activity against human liver cancer cell lines.


Litchi fruit pericarp (LFP) extract contains significant amounts of polyphenolic compounds, and exhibits powerful antioxidative activity against fat oxidation in vitro. The purpose of this study is to confirm the anticancer activity of LFP extract against hepatocellular carcinoma in vitro and in vivo, and to elucidate the mechanism of its activity. Human hepatocellular carcinoma cell line was tested in vitro for cytotoxicity, colony formation inhibition, and cell cycle distribution through flow cytometry after treatment with water-soluble crude ethanolic extract (CEE) from LFP. Murine hepatoma bearing-mice were fed doses of 0.15, 0.3, and 0.6g/kg/day of water-soluble CEE in DH(2)O p.o. for 10 days, respectively, to test the anticancer activity and BrdU incorporation of cancer cells in vivo. LFP extract demonstrated a dose- and time-dependent inhibitory effect on cancer cell growth; IC(50) was 80microg/ml, and significantly inhibited colony formation in vitro, tumor growth and BrdU incorporation into cancer cells in vivo. The tumor inhibitory rates at doses of 0.15, 0.3, and 0.6g/kg/day were 17.31% (P>0.05), 30.77% (P<0.05), and 44.23% (P<0.01), respectively. BrdU labeled tumor cells of treated animals were 11.80+/-2.79%, and were significantly lower than that in untreated controls (23.00+/-5.42%, P<0.05). Our findings showed that LFP extract exhibited potential anticancer activity against hepatocellular carcinoma in vitro and in vivo through proliferating inhibition and apoptosis induction of cancer cells. 

J Am Mosq Control Assoc. 2006 Sep;22(3):497-500. PMID: 16300877

215
[+]

EGCG, a green tea polyphenol, induces programmed cell death in human lymphoblastoid B cells.


(-)-Epigallocatechin-3-gallate (EGCG), a major constituent of green tea polyphenols, has been shown to suppress cancer cell proliferation and induce apoptosis. In this study we investigated its efficacy and the mechanism underlying its effect using human B lymphoblastoid cell line Ramos, and effect of co-treatment with EGCG and a chemotherapeutic agent on apoptotic cell death. EGCG induced dose- and time-dependent apoptotic cell death accompanied by loss of mitochondrial transmembrane potential, release of cytochrome c into the cytosol, and cleavage of pro-caspase-9 to its active form. EGCG also enhanced production of intracellular reactive oxygen species (ROS). Pretreatment with diphenylene iodonium chloride, an inhibitor of NAD(P)H oxidase and an antioxidant, partially suppressed both EGCG-induced apoptosis and production of ROS, implying that oxidative stress is involved in the apoptotic response. Furthermore, we showed that combined-treatment with EGCG and a chemotherapeutic agent, etoposide, synergistically induced apoptosis in Ramos cells.

Biochem Biophys Res Commun. 2007 Nov 3;362(4):951-7. Epub 2007 Aug 24. PMID: 17803956

216
[+]

EGCG, a green tea polyphenol, induces programmed cell death in human lymphoblastoid B cells.


PURPOSE: Green tea polyphenol, (-)-epigallocatechin-3-gallate, has been shown to inhibit cellular proliferation and induce apoptosis of various cancer cells. The aim of this study was to investigate the possibility of (-)-epigallocatechin-3-gallate as a novel therapeutic agent for the patients with B-cell malignancies including multiple myeloma. EXPERIMENTAL DESIGN: We investigated the effects of (-)-epigallocatechin-3-gallate on the induction of apoptosis in HS-sultan as well as myeloma cells in vitro and further examined the molecular mechanisms of (-)-epigallocatechin-3-gallate-induced apoptosis. RESULTS: (-)-Epigallocatechin-3-gallate rapidly induced apoptotic cell death in various malignant B-cell lines in a dose- and time-dependent manner. (-)-Epigallocatechin-3-gallate-induced apoptosis was in association with the loss of mitochondrial transmembrane potentials (Deltapsim); the release of cytochrome c, Smac/DIABLO, and AIF from mitochondria into the cytosol; and the activation of caspase-3 and caspase-9. Elevation of intracellular reactive oxygen species (ROS) production was also shown during (-)-epigallocatechin-3-gallate-induced apoptosis of HS-sultan and RPMI8226 cells as well as fresh myeloma cells. Antioxidant, catalase, and Mn superoxide dismutase significantly reduced ROS production and (-)-epigallocatechin-3-gallate-induced apoptosis, suggesting that ROS plays a key role in (-)-epigallocatechin-3-gallate-induced apoptosis in B cells. Furthermore, a combination with arsenic trioxide (As2O3) and (-)-epigallocatechin-3-gallate significantly enhanced induction of apoptosis compared with As2O3 alone via decreased intracellular reduced glutathione levels and increased production of ROS. CONCLUSIONS: (-)-Epigallocatechin-3-gallate has potential as a novel therapeutic agent for patients with B-cell malignancies including multiple myeloma via induction of apoptosis mediated by modification of the redox system. In addition, (-)-epigallocatechin-3-gallate enhanced As2O3-induced apoptosis in human multiple myeloma cells.

Support Care Cancer. 2010 Jun;18(6):751-9. Epub 2009 Aug 14. PMID: 16115949

217
[+]

Pomegranate polyphenols have a protective effect against UVA- and UVB-induced cell damage.


Exposure to ultraviolet (UV) radiation has been associated with several acute and chronic conditions, including sunburn, edema, hyperplasia, immunosuppression, photoaging, and skin cancer. The role of naturally occurring phytochemicals in the prevention of such UV-related conditions has captured increased interest. Pomegranate ( Punica granatum L.) is a rich source of polyphenolics, which have been shown to exert anti-inflammatory, antioxidant, and anticarcinogenic activity in numerous in vivo and in vitro studies. This work investigated potential protective effects of a pomegranate fruit extract standardized to punicalagins against UVA- and UVB-induced damage in SKU-1064 human skin fibroblast cells. Pomegranate extract (PE), in a range from 5 to 60 mg/L, was effective at protecting human skin fibroblasts from cell death following UV exposure, likely related to a reduced activation of the pro-inflammatory transcription factor NF-kappaB, a downregulation of proapoptotic caspase-3, and an increased G0/G1 phase, associated with DNA repair. Higher polyphenolic concentrations (500-10000 mg/L) were needed to achieve a significant reduction in UV-induced reactive oxygen species levels and increased intracellular antioxidant capacity (from 1.9 to 8.6 muM Trolox equivalents/mL). Results from this study demonstrate the protective effects of PE against UVA- and UVB-induced cell damage and the potential use of pomegranate polyphenolics in topical applications.

J Agric Food Chem. 2008 Sep 24;56(18):8434-41. Epub 2008 Aug 22. PMID: 18717570

218
[+]

EGCG changes the phenotype of invasive breast cancer cells, repressing malignancy.


Previously, we showed that the bioactive green tea polyphenol epigallocatechin-3-gallate (EGCG) inhibits growth in soft agar of breast cancer cells with Her-2/neu overexpression. Using gene expression profiling, here we show that EGCG treatment of Her-2/neu-driven mammary tumor cells alters the expression of key regulators in the epithelial to mesenchymal transition (EMT) pathway, reducing invasive phenotype. Specifically, the epithelial genes E-cadherin, gamma-catenin, MTA3, and estrogen receptor alpha (ERalpha) were up-regulated by EGCG, whereas the proinvasive snail gene was down-regulated. Consistently, EGCG inhibited branching colony growth and invasion in Matrigel. EGCG treatment similarly inhibited invasive phenotype of mouse mammary tumor cells driven by Nuclear Factor-kappaB c-Rel and protein kinase CK2, frequently found overexpressed in human breast disease. Recently, we identified the Forkhead box O transcription factor FOXO3a as a major transcriptional regulator of ERalpha. Given the pivotal role of ERalpha in preventing EMT, we hypothesized that the activation of FOXO3a by EGCG plays an important role in the observed reversal of invasive phenotype in ERalpha-positive breast cancer cells. EGCG treatment activated FOXO3a. Ectopic expression of a constitutively active FOXO3a overrode transforming growth factor-beta1-mediated invasive phenotype and induced a more epithelial phenotype, which was dependent on ERalpha expression and signaling. Conversely, a dominant negative FOXO3a reduced epithelial phenotype of ERalpha-low breast cancer cells. These results identify, for the first time, a role for FOXO3a in the inhibition of invasive phenotype in breast cancer cells with active ERalpha signaling and elucidate a novel mechanism whereby EGCG represses EMT of breast cancer cells.

Cancer Res. 2007 Jun 15;67(12):5763-70. PMID: 17575143

219
[+]

Curcumin may have therapeutic potential for bladder cancer patients via anti-inflammatory, antioxidant and anti-carcinogenic activities.


Curcumin, a polyphenol compound derived from Curcuma longa Linn, has been recognized as a promising anti-cancer drug due to its multiple properties including anti-inflammatory, anti-oxidant and anti-carcinogenic activities. To elucidate the mechanisms by which curcumin inhibits human bladder carcinoma T24 cell proliferation, we tested the effects of curcumin on specific cell cycle pathways and on the expression of cyclooxygenases (COXs). Curcumin inhibited the growth of T24 cells and induced G2/M arrest in a concentration-dependent manner, effects associated with the down-regulation of cyclin A and up-regulation of cyclin-dependent kinase (Cdk) inhibitor p21 (WAF1/CIP1). However, other G2/M regulatory molecules, such as cyclin A, Cdc2, Cdk2, Wee1 and Cdc25C, were not modulated by curcumin treatment. Furthermore, curcumin decreased the levels of COX-2 mRNA and protein expression without significant changes in the levels of COX-1, which correlated with a decrease in prostaglandin E2 (PGE2) synthesis. These observations suggest that curcumin may have therapeutic potential for bladder cancer patients.

Oncol Rep. 2006 May;15(5):1225-31. PMID: 16596191

220
[+]

Resveratrol and querctin work synergistically to inhibit glioma cell lines.


Glioma is the most frequent and malignant primary human brain tumor with dismal prognosis despite multimodal therapy. Resveratrol and quercetin, two structurally related and naturally occurring polyphenols, are proposed to have anticancer effects. We report here that resveratrol and quercetin decreased the cell number in four glioma cell lines but not in rat astrocytes. Low doses of resveratrol (10 microM) or quercetin (25 microM) separately had no effect on apoptosis induction, but had a strong effect on caspase 3/7 activation when administered together. Western blot analyses showed that resveratrol (10 microM) and quercetin (25 microM) caused a reduction in phosphorylation of Akt, but this reduction was not sufficient by itself to mediate the effects of these polyphenols. Most important, resveratrol and quercetin chronically administered presented a strong synergism in inducing senescence-like growth arrest. These results suggest that the combination of polyphenols can potentialize their antitumoral activity, thereby reducing the therapeutic concentration needed for glioma treatment. (Cancer Sci 2009).

Cancer Sci. 2009 May 12. PMID: 19496785

221
[+]

Curcumin induces programmed cell death in human malignant gliobastoma cells. - Article 1


Glioblastoma is the most malignant human brain tumor that shows poor response to existing therapeutic agents. Search continues for an effective therapy for controlling this deadliest brain tumor. Curcumin (CCM), a polyphenolic compound from Curcuma longa, possesses anti-cancer properties in both in vitro and in vivo. In the present investigation, we evaluated the therapeutic efficacy of CCM against human malignant glioblastoma U87MG cells. Trypan blue dye exclusion test showed decreased viability of U87MG cells with increasing dose of CCM. Wright staining and ApopTag assay, respectively, showed the morphological and biochemical features of apoptosis in U87MG cells treated with 25 microM and 50 microM of CCM for 24 h. Western blotting showed activation of caspase-8, cleavage of Bid to tBid, increase in Bax:Bcl-2 ratio, and release of cytochrome c from mitochondria followed by activation of caspase-9 and caspase-3 for apoptosis. Also, CCM treatments increased cytosolic level of Smac/Diablo to suppress the inhibitor-of-apoptosis proteins and down regulated anti-apoptotic nuclear factor kappa B (NFkappaB), favoring the apoptosis. Increased activities of calpain and caspase-3 cleaved 270 kDa alpha-spectrin at specific sites generating 145 kDa spectrin break down product (SBDP) and 120 kDa SBDP, respectively, leading to apoptosis in U87MG cells. Results show that CCM is an effective therapeutic agent for suppression of anti-apoptotic factors and activation of calpain and caspase proteolytic cascades for apoptosis in human malignant glioblastoma cells.

Neurochem Res. 2007 Dec;32(12):2103-13. Epub 2007 Jun 12. PMID: 17562168

222
[+]

EGCG, a green tea polyphenol, may inhibit invasive medulloblastomas.


Epigallocatechin-3-gallate (EGCG), the major green tea polyphenol, can reach the brain following oral intake and could thus act as an anti-tumoral agent targeting several key steps of brain cancer cells invasive activity. Because integrin-mediated extracellular matrix recognition is crucial during the cell adhesion processes involved in carcinogenesis, we have investigated the effects of EGCG on different cellular integrins of the pediatric brain tumor-derived medulloblastoma cell line DAOY. Using flow cytometry, we report the levels of expression of several cell surface integrins in DAOY. These include high expression of alpha2, alpha3, and beta1 integrins, as well as alphav and beta3 integrins. Moreover, we provide evidence that EGCG can antagonize DAOY cell migration specifically on collagen by increasing cell adhesive ability through specific gene and protein upregulation of the beta1 integrin subunit. Our results suggest that this naturally occurring green tea polyphenol may thus be used as a nutraceutical therapeutic agent in targeting the invasive character of medulloblastomas. Copyright 2003 Wiley-Liss, Inc.

J Cell Biochem. 2003 Nov 1;90(4):745-55. PMID: 14587030

223
[+]

Ellagic acid fractions from muscadine grapes induce programmed cell death in human colon cancer cells.


Possible anticancer mechanisms exerted by polyphenolic compounds contained in fruits and vegetables include antioxidant activity, the inhibition of proliferation, and the induction of apoptosis in cancer cells. This study examined the effects of four isolated polyphenolic extracts from red muscadine grapes (Vitis rotundifolia) on vital cell parameters and the induction of apoptosis in Caco-2 colon carcinoma cells. The magnitude of effects in cell culture was then correlated to polyphenolic composition and antioxidant capacity. Whereas anticancer effects of individual polyphenolic compounds have been demonstrated multiple times, information relating to anticancer effects of polyphenolic extracts is not available in abundance. All four extracts induced apoptosis, decreased cell number, and caused alterations in cell cycle kinetics in a concentration-dependent manner. The efficacy of the polyphenolics on vital cell parameters correlated well to the presence of ellagic acid glycosides and flavonoids and also to the antioxidant capacity. This study demonstrated the anticancer properties of ellagic acid rich extracts from red muscadine juice.

J Agric Food Chem. 2006 Jul 26;54(15):5336-43. PMID: 16848514

224
[+]

Muscadine grapes contain phenolics with anticancer activity.


Muscadine grapes have unique aroma and flavor characteristics. Although a few studies reported high polyphenols content of muscadine grapes, little research has been conducted to evaluate the phenolic compounds bioactivities in any muscadine grape cultivar. The objective of this study was to evaluate the effect of phenolic compounds in muscadine grapes on cancer cell viability and apoptosis. Four cultivars of muscadine (Carlos, Ison, Noble, and Supreme) were assessed in this study. Phenolic compounds were extracted from muscadine skins and further separated into phenolic acids, tannins, flavonols, and anthocyanins using HLB cartridge and LH20 column. Some individual phenolic acids and flavonoids were identified by HPLC. Anthocyanin fractions were more than 90% pure. The effect of different fractions on the viability and apoptosis of two colon cancer cell lines (HT-29 and Caco-2) was evaluated. A 50% inhibition of cancer cell population growth for the two cell lines was observed at concentrations of 1-7 mg/mL for crude extracts. The phenolic acid fractions showed a 50% inhibition at the level of 0.5-3 mg/mL. The greatest inhibitory activity was found in the anthocyanin fraction, with a 50% inhibition at concentrations of approximately 200 microg/mL in HT-29 and 100-300 microg/mL in Caco-2. Anthocyanin fractions also resulted in 2-4 times increase in DNA fragmentation, indicating the induction of apoptosis. These findings suggest that polyphenols from muscadine grapes may have anticancer properties.

J Agric Food Chem. 2005 Nov 2;53(22):8804-12. PMID: 16248588

225
[+]

Green tea extract appears to have signifcant therapeutic effects in low grade B-cell malignancies.


Green tea or its constituents have long been touted as a health promoting substance including claims it may have cancer prevention properties. We previously reported the in vitro ability of one tea polyphenol, epigallocatechin gallate (EGCG), to induce apoptotic cell death in the leukemic B-cells from a majority of patients with chronic lymphocytic leukemia (CLL). After the publication of our findings many patients with CLL and other low grade lymphomas began using over-the-counter products containing tea polyphenols despite the absence of evidence to suggest clinical benefit, definition of possible toxicities, or information on optimal dose and schedule. We have become aware of four patients with low grade B-cell malignancies seen in our clinical practice at Mayo Clinic who began, on their own initiative, oral ingestion of EGCG containing products and subsequently appeared to have an objective clinical response. Three of these four patients met criteria for partial response (PR) by standard response criteria. Although spontaneous remission/regression is occasionally observed in individuals with low grade B-cell malignancies, such events are rare. Several patients presented here had documented steady clinical, laboratory, and/or radiographic evidence of progression immediately prior to initiation of over-the-counter green tea products and then developed objective responses shortly after self-initiating this therapy. Such anecdotes highlight the need for clinical trials of tea polyphenols to define the optimal dosing, schedule, toxicities, and clinical efficacy before widespread use can be recommended. An NCI sponsored phase I/II trial of de-caffeinated green tea extracts for patients with asymptomatic, early stage CLL opened at Mayo Clinic in August 2005.

J Agric Food Chem. 2007 Dec 12;55(25):10150-5. Epub 2007 Nov 15. PMID: 16325256

226
[+]

Black tea polyphenol inhibits aromatase activity and attenuates tamoxifen resistance in HER2/neu transfected human breast cancer cells.


The aromatase enzyme, which converts androstenedione to oestrone, regulates the availability of oestrogen to support the growth of hormone-dependent breast tumours. In this study, we investigated the inhibitory effects of black tea polyphenols on aromatase activities. We found that black tea polyphenols, TF-1, TF-2 and TF-3, significantly inhibited rat ovarian and human placental aromatase activities. In addition, using an in vivo model, these black tea polyphenols also inhibited the proliferation induced by 100 nM dehydroepiandrosterone (DHEA) in MCF-7 cells. Transfection of HER2/neu in MCF-7 breast cancer cells appeared to be associated with an increased resistance of the cells to hormonal therapy. Interestingly, unlike the selective oestrogen receptor modulator (SERM) tamoxifen, black tea polyphenols had antiproliferation effects in breast cancer cells with hormonal resistance. The inhibitory effect of black tea polyphenols on hormone-resistant breast cancer cells suppressed the basal receptor tyrosine phosphorylation in HER2/neu-overexpressing MCF-7 cells. These findings suggest the use of black tea polyphenols may be beneficial in the chemoprevention of hormone-dependent breast tumours and represent a possible remedy to overcome hormonal resistance of hormone-independent breast tumours.

Eur J Cancer. 2004 Sep;40(14):2165-74. PMID: 15341993

227
[+]

EGCG, a green tea polyphenol, exhibits antiproliferative activity against pancreatic cancer cell lines in vitro.


(-)-Epigallocatechin-3-gallate [(-)-EGCG], the most abundant polyphenolic catechin in green tea, showed chemoprevention and anticancer activities. (-)-EGCG was reported to bind to the C-terminal domain of heat shock protein 90 (Hsp90). The purpose of this study is to investigate (-)-EGCG as a novel Hsp90 inhibitor to impair Hsp90 superchaperone complex for simultaneous downregulation of oncogenic proteins in pancreatic cancer cells. MTS assay showed that (-)-EGCG exhibited antiproliferative activity against pancreatic cancer cell line Mia Paca-2 in vitro with IC50 below 50 muM. (-)-EGCG increased caspase-3 activity up to 3-fold in a time- and concentration-dependent manner. Western blotting analysis demonstrated that (-)-EGCG induced downregulation of oncogenic Hsp90 client proteins by approximately 70-95%, including Akt, Cdk4, Raf-1, Her-2, and pERK. Co-immunoprecipitation showed that (-)-EGCG decreased the association of cochaperones p23 and Hsc70 with Hsp90 by more than 50%, while it had little effect on the ATP binding to Hsp90. Proteolytic fingerprinting assay confirmed direct binding between (-)-EGCG and the Hsp90 C-terminal domain. These data suggest that the binding of (-)-EGCG to Hsp90 impairs the association of Hsp90 with its cochaperones, thereby inducing degradation of Hsp90 client proteins, resulting antiproliferating effects in pancreatic cancer cells.
1: Mol Pharm. 2009 Jul-Aug;6(4):1152-9. PMID:19438225
228
[+]

EGCG, a green tea polyphenol, induces programmed cell death and growth arrest in pancreatic cancer cell lines.


 Epigallocatechin-3-gallate (EGCG), a major polyphenolic constituent of green tea, can exert growth suppressive effect on human pancreatic cancer cells by evoking apoptotic response. EGCG-induced apoptosis of pancreatic cancer cells is accompanied by growth arrest at an earlier phase of cell cycle along with depolarization of mitochondrial membrane. In this report, using MIA PaCa-2 cells as in vitro model, we demonstrate EGCG-induced cell death involves activation of caspase-8 and disappearance of intact 21 kDa Bid protein. Furthermore, exogenous expression of dominant negative caspase-8 or dominant negative FADD significantly abrogates apoptosis inducing ability of EGCG in MIA PaCa-2 cells. RNase protection assay revealed upregulation of the members of death receptor family, thus indicating the involvement of transmembrane extrinsic signaling in this polyphenol triggered pancreatic carcinoma cell death. Based on this, we examined the effect of EGCG and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) together on pancreatic cancer cells. A synergistic increase in apoptosis and cleavage of procaspase-3 was noted. Furthermore, clonogenic cell survival assay demonstrates the significant diminishment of MIA PaCa-2 cell proliferation in the presence of both EGCG and TRAIL. This combination treatment strategy has potential therapeutic advantage for pancreatic carcinoma.

Int J Oncol. 2009 Jan;34(1):281-6. PMID: 19082499

229
[+]

The food-derived polyphenols quercetin, trans-resveratrol and genistein inhibit pancreatic cancer growth and prevent metastasis, in vitro.


There is increasing evidence that food-derived polyphenols have a beneficial effect for cancers. Our purpose was to determine the effect and mechanism of action of these compounds on pancreatic cancer. We measured effects of quercetin on pancreatic cancer in a nude mouse model. We also investigated the effects of quercetin, rutin, trans-resveratrol and genistein on apoptosis and underlying signaling in pancreatic carcinoma cells in vitro. Quercetin decreased primary tumor growth, increased apoptosis and prevented metastasis in a model of pancreatic cancer. In vitro quercetin and trans-resveratrol, but not rutin, markedly enhanced apoptosis, causing mitochondrial depolarization and cytochrome c release followed by caspase-3 activation. In addition, the effect of a combination of quercetin and trans-resveratrol on mitochondrial cytochrome c release and caspase-3 activity was greater than the expected additive response. The inhibition of mitochondrial permeability transition prevented cytochrome c release, caspase-3 activation and apoptosis caused by polyphenols. Nuclear factor-kappa B activity was inhibited by quercetin and trans-resveratrol, but not genistein, indicating that this transcription factor is not the only mediator of the polyphenols' effects on apoptosis. The results suggest that food-derived polyphenols inhibit pancreatic cancer growth and prevent metastasis by inducing mitochondrial dysfunction, resulting in cytochrome c release, caspase activation and apoptosis. Copyright 2002 Wiley-Liss, Inc.

Int J Cancer. 2002 Apr 10;98(5):761-9. PMID: 11920648

230
[+]

Ellagic acid induces programmed cell death in pancreatic cancer cells.


AIM: To determine the effect of ellagic acid on apoptosis and proliferation in pancreatic cancer cells and to determine the mechanism of the pro-survival effects of ellagic acid. METHODS: The effect of ellagic acid on apoptosis was assessed by measuring phosphatidylserine externalization, caspase activity, mitochondrial membrane potential and DNA fragmentation; and proliferation by measuring DNA thymidine incorporation. Mitochondrial membrane potential was measured in permeabilized cells, and in isolated mitochondria. Nuclear factor kappa B (NF-kappa B) activity was measured by electromobility shift assay (EMSA). RESULTS: We show that ellagic acid, a polyphenolic compound in fruits and berries, at concentrations 10 to 50 mmol/L stimulates apoptosis in human pancreatic adenocarcinoma cells. Further, ellagic acid decreases proliferation by up to 20-fold at 50 mmol/L. Ellagic acid stimulates the mitochondrial pathway of apoptosis associated with mitochondrial depolarization, cytochrome C release, and the downstream caspase activation. Ellagic acid does not directly affect mitochondria. Ellagic acid dose-dependently decreased NF-kappa B binding activity. Furthermore, inhibition of NF-kappa B activity using IkB wild type plasmid prevented the effect of ellagic acid on apoptosis. CONCLUSION: Our data indicate that ellagic acid stimulates apoptosis through inhibition of the prosurvival transcription factor NF-kappa B.

World J Gastroenterol. 2008 Jun 21;14(23):3672-80. PMID: 18595134

231
[+]

Gossypol, a polyphenol isolated from cottonseeds, inhibits pancreatic cancer cell growth.


OBJECTIVES: In pancreatic cancer, several important survival molecules such as EGFR, NF-kappaB, and Bcl-2 or Bcl-XL are highly activated. Thus, agents that inhibit NF-kappaB activation, together with agents that directly inhibit Bcl-2 or Bcl-XL protein function, may lead to enhanced cell killing. (-)-Gossypol, a natural polyphenolic compound isolated from cottonseeds, is a dual and potent small-molecule inhibitor of Bcl-2 and Bcl-XL proteins, with a Ki value in the 300-600 nM range for both proteins. METHODS:: The BxPC-3 human pancreatic cell line was used in this study. (-)-Gossypol was dissolved in DMSO at 20 mmol/L as stock solution, and genistein was dissolved in 0.1 M Na2CO3 to make a 10 mM stock solution. For cell viability, apoptosis, and NF-kappaB studies, MTT assay, histone/DNA ELISA, and Electrophoretic Mobility Shift Assay (EMSA) were used, respectively. Coimmunoprecipitation experiments were designed to study Bcl-XL/Bim heterodimerization, and Western blots to study cytochrome c release. RESULTS: (-)-Gossypol showed a concentration-dependent growth inhibition effect against BxPC-3 pancreatic cancer cell line and induced apoptosis with no effect on normal peripheral blood lymphocytes. Results from coimmunoprecipitation experiments indicate that the effect of (-)-gossypol is mediated, at least, in part via disrupting the heterodimerization of Bcl-XL with Bim in BxPC-3 pancreatic cancer cells. (-)-Gossypol completely disrupts Bcl-XL/Bim heterodimerization with no change in the total Bcl-XL or Bim protein, indicating that (-)-gossypol treatment does not affect the levels of Bcl-XL and Bim proteins. We have previously shown that genistein, a prominent soy isoflavone, transcriptionally down-regulates Bcl-2, Bcl-XL, VEGF, MMP-9, and uPAR via inhibiting NF-kappaB activity. In this study, genistein down-regulated NF-kappaB DNA binding activity and inhibited the growth of BxPC-3 pancreatic cancer cells. In addition, the combination of (-)-gossypol with genistein showed significantly greater growth inhibition compared with either agent alone. CONCLUSION: From these results, we conclude that inhibition of NF-kappaB activity and direct inhibition of Bcl-2 or Bcl-XL function should serve as a novel strategy for pancreatic cancer therapy.      

Pancreas. 2005 Nov;31(4):317-24. PMID: 16258364

232
[+]

Carotenoids from red palm and green tea polyphenols exhibit chemopreventive effects on pancreatic cancer cell lines.


The effects of alpha-carotene, beta-carotene, palm carotene, and green tea polyphenols (GTP) on the progression stage of pancreatic carcinogenesis after rapid production of ductal lesions were studied in Syrian hamsters. Dose threshold inhibitory effects were noted for beta-carotene, 25 ppm, and palm carotene, 40 ppm, which includes 24 ppm beta-carotene reducing the numbers of putative preneoplastic lesions of duct epithelial hyperplasia and atypical hyperplasia, as well as carcinoma in situ and invasive carcinomas. GTP at doses of 500 and 5000 ppm, but not 100 ppm, also significantly decreased the numbers of hyperplasia and total duct lesions. Combined administration of 40 ppm palm carotene, and 50 ppm GTP similarly inhibited the lesion development. Alpha-carotene, however, did not affect pancreatic carcinogenesis. The results suggest that chemopreventive effects are exerted by beta-carotene and GTP above critical doses and that combined administration of palm carotene and GTP might be a candidate chemoprevention strategy for pancreatic cancer in humans.

Pancreas. 1998 Jan;16(1):13-8. PMID: 9436857

233
[+]

Blackberry extract has anti-inflammatory, anti-oxidant and anti-proliferative activity, in vitro.


Blackberries are rich in polyphenols, including anthocyanins. Polyphenols are hypothesized to have biological activities that may impact positively on human health. In these studies, an anthocyanin-rich extract from Hull blackberries grown in Kentucky was obtained and fully characterized in terms of total anthocyanin and phenolic content, polymeric color, anthocyanin composition, and total antioxidant capacity. In vitro cell culture studies showed that the blackberry extract inhibited HT-29 colon tumor cell growth in a concentration-dependent manner with 49.2 microg of total anthocyanins/mL inhibiting HT-29 cell growth up to 66% at 72 hours. Likewise, in a concentration-dependent manner, total anthocyanin concentrations in the range of 0-40 microg/mL suppressed both high-dose (10 microg/mL) and low-dose (0.1 microg/mL) lipid A-induced interleukin-12 release from mouse bone marrow-derived dendritic cells. These results suggest that Hull blackberry extract (HBE) has potent antioxidant, antiproliferative, and anti-inflammatory activities and that HBE-formulated products may have the potential for the treatment and/or prevention of cancer and/or other inflammatory diseases.  

J Med Food. 2007 Jun;10(2):258-65. PMID: 17651061

234
[+]

Korean white lotus has antioxidant and antiproliferative activity against human pulmonary cancer and human gastric cancer cell lines.


In traditional Korean medicine, lotus (Nelumbo nucifera Gaertn) roots have been used as an antidiabetic and an antiproliferative remedy. However, scientific publications on lotus properties are very limited. Therefore, it was decided to investigate the Korean white lotus cultivars in order to find out their bioactivity. It was found that all lotus cultivars (Inchisa, Muan, Garam, and Chungyang) possess high amounts of bioactive compounds: total phenols, between 7.95 +/- 0.8 and 4.21 +/- 0.3 mg of gallic acid equivalents (GAE)/g dry weight (DW); ascorbic acid, between 15.8 +/- 1.1 and 22.3 +/- 1.7 mg of ascorbic acid/g DW; and amino acids, between 15.05 +/- 0.82% and 16.62 +/- 0.90% DW. The highest contents of polyphenols (7.95 +/- 0.8 mg of GAE/g DW) and the highest levels of antioxidant [by 2,2-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and 1,1-diphenyl-2-picrylhydrazyl assays, 54.27 +/- 6.1 and 21.98 +/- 2.5 microM Trolox equivalents/g DW, respectively] and antiproliferative activities on both human cancer cell lines (Calu-6 for human pulmonary carcinoma and SMU-601 for human gastric carcinoma, 59.75 +/- 3.99% and 71.21 +/- 2.79% cell viability, respectively) were found in the Chungyang cultivar. Fluorometry and Fourier transform infrared spectroscopy can be applied as rapid methods for determination of bioactive compounds, such as polyphenols. The correlation between the bioactive compounds and the antioxidant activity was high. In conclusion, all Korean white lotus cultivars are valuable medicinal foods, and in order to receive the best results a combination of lotus cultivars has to be consumed.    

J Med Food. 2009 Oct;12(5):1057-64. PMID: 19857070

235
[+]

Plant polyphenols may be useful in skin diseases associated with solar UV radiation-induced inflammation, oxidative stress and DNA damage.


 Epidemiological, clinical and laboratory studies have implicated solar ultraviolet (UV) radiation in various skin diseases including, premature aging of the skin and melanoma and non-melanoma skin cancers. Chronic UV radiation exposure-induced skin diseases or skin disorders are caused by the excessive induction of inflammation, oxidative stress and DNA damage, etc. The use of chemopreventive agents, such as plant polyphenols, to inhibit these events in UV-exposed skin is gaining attention. Chemoprevention refers to the use of agents that can inhibit, reverse or retard the process of these harmful events in the UV-exposed skin. A wide variety of polyphenols or phytochemicals, most of which are dietary supplements, have been reported to possess substantial skin photoprotective effects. This review article summarizes the photoprotective effects of some selected polyphenols, such as green tea polyphenols, grape seed proanthocyanidins, resveratrol, silymarin and genistein, on UV-induced skin inflammation, oxidative stress and DNA damage, etc., with a focus on mechanisms underlying the photoprotective effects of these polyphenols. The laboratory studies conducted in animal models suggest that these polyphenols have the ability to protect the skin from the adverse effects of UV radiation, including the risk of skin cancers. It is suggested that polyphenols may favorably supplement sunscreens protection, and may be useful for skin diseases associated with solar UV radiation-induced inflammation, oxidative stress and DNA damage.

Arch Dermatol Res. 2009 Nov 7. PMID: 19898857

236
[+]

Resveratrol inhibits rhabdomyosarcoma cell proliferation.


Rhabdomysarcoma is the most common soft tissue tumour in children under the age of 15. Although the introduction of multimodal treatment programmes, including chemotherapy, radiation therapy and excision have increased the overall survival, the chemotherapeutic agents currently used for the treatment of rhabdomyosarcoma exhibit considerable toxicity. The aim of this study was to investigate the effects and possible mechanism(s) of action of resveratrol on human embryonal rhabdomyosarcoma (RD) cells. Resveratrol is a natural polyphenolic compound produced in a number of edible plants and has received considerable attention as a potential chemopreventive and/or chemotherapeutic agent against various types of cancers. In the present study, resveratrol was shown to inhibit cell proliferation of RD cells in a dose-dependent manner with an IC50 of 48.1 micromol/l and induce an arrest in the S/G2 phase of the cell cycle. As evident from immunocytochemical data, resveratrol treatment increased the size of the RD cells. Furthermore, resveratrol treatment resulted in a significant downregulation of cyclin B expression as demonstrated by western blot analyses. In conclusion, the present study shows that resveratrol exerts a strong inhibition of rhabdomyosarcoma cell proliferation in part by arresting cells in S/G2 phase of the cell cycle. These findings warrant further investigation to establish potential use of resveratrol as a relatively non-toxic chemotherapeutic agent for the treatment of rhabdomyosarcoma.  

Eur J Cancer Prev. 2005 Aug;14(4):351-6. PMID: 16030425

237
[+]

Oolong tea polyphenol extract induces programmed cell death in human stomach cancer cells.


The exposure of human stomach cancer KATO III cells to oolong tea polyphenol extact [OTPE] containing oolong tea polyphenol trimer [OTP trimer] as a main component, led to both growth inhibition and the induction of apoptosis. Morphological change showing apoptotic bodies was observed in the cells treated with OTPE. The fragmentation by OTPE of DNA to oligonucleosomalsized fragments that are characteristics of apoptosis was observed to be concentration- and time-dependent. These data suggest that the growth inhibition by OTPE results from the induction of apoptosis in the KATO III cells.

Anticancer Res. 2000 Nov-Dec;20(6B):4403-6. PMID: 11205279

238
[+]

Resveratrol induces cell cycle arrest and programmed cell death in human gastric cancer cells.


Resveratrol, a polyphenolic phytochemical present in berries, grapes, and wine, has emerged as a promising chemopreventive candidate. Because there is scant information regarding natural agents that prevent, suppress, or reverse gastric carcinogenesis, the aim of the present study was to determine the chemopreventive potential of resveratrol against gastric cancer by investigating cellular and molecular events associated with resveratrol treatment of human gastric adenocarcinoma cells. We determined the action of resveratrol on cellular function and cellular integrity by measuring DNA synthesis, cellular proliferation, cell cycle distribution, cytolysis, apoptosis, and phosphotransferase activities of two key signaling enzymes, protein kinase C (PKC) and mitogen-activated protein kinases (ERK1/ERK2), in human gastric adenocarcinoma KATO-III and RF-1 cells. Resveratrol inhibited [3H]thymidine incorporation into cellular DNA of normally proliferating KATO-III cells and of RF-1 cells whose proliferation was stimulated with carcinogenic nitrosamines. Treatment with resveratrol arrested KATO-III cells in the G(0)/G(1) phase of the cell cycle and eventually induced apoptotic cell death, but had a minimal effect on cell lysis. Resveratrol treatment had no effect on ERK1/ERK2 activity but significantly inhibited PKC activity of KATO-III cells and of human recombinant PKCalpha. Results indicate that resveratrol has potential as a chemopreventive agent against gastric cancer because it exerts an overall deactivating effect on human gastric adenocarcinoma cells. Resveratrol-induced inhibition of PKC activity and of PKCalpha, without any change in ERK1/ERK2 activity, suggests that resveratrol utilizes a PKC-mediated mechanism to deactivate gastric adenocarcinoma cells.

Invest New Drugs. 2005 Mar;23(2):111-9. PMID: 11709203

239
[+]

Curcumin, resveratrol and flavonoids act as anti-inflammatory, cyto- and DNA-protective dietary compounds.


Numerous dietary compounds, ubiquitous in fruits, vegetables and spices have been isolated and evaluated during recent years for their therapeutic potential. These compounds include flavonoid and non-flavonoid polyphenols, which describe beneficial effects against a variety of ailments. The notion that these plant products have health promoting effects emerged because their intake was related to a reduced incidence of cancer, cardiovascular, neurological, respiratory, and age-related diseases. Exposure of the body to a stressful environment challenges cell survival and increases the risk of chronic disease developing. The polyphenols afford protection against various stress-induced toxicities through modulating intercellular cascades which inhibit inflammatory molecule synthesis, the formation of free radicals, nuclear damage and induce antioxidant enzyme expression. These responses have the potential to increase life expectancy. The present review article focuses on curcumin, resveratrol, and flavonoids and seeks to summarize their anti-inflammatory, cytoprotective and DNA-protective properties.

Toxicology. 2009 Nov 10. Epub 2009 Nov 10. PMID: 19903510

240
[+]

Pomegranate fruit extract impairs invasion and motility in human breast cancer.


PURPOSE: Pomegranate fruit extracts (PFEs) possess polyphenolic and other compounds with antiproliferative, pro-apoptotic and anti-inflammatory effects in prostate, lung, and other cancers. Because nuclear transcription factor-kB (NF-kB) is known to regulate cell survival, proliferation, tumorigenesis, and inflammation, it was postulated that PFEs may exert anticancer effects at least in part by modulating NF-kB activity. EXPERIMENTAL DESIGN: The authors investigated the effect of a novel, defined PFE consisting of both fermented juice and seed oil on the NF-kB pathway, which is constitutively active in aggressive breast cancer cell lines. The effects of the PFE on NF-kB-regulated cellular processes such as cell survival, proliferation, and invasion were also examined. RESULTS: Analytical characterization of the bioactive components of the PFE revealed active constituents, mainly ellagitannins and phenolic acids in the aqueous PFE and conjugated octadecatrienoic acids in the lipid PFE derived from seeds.The aqueous PFE dose-dependently inhibited NF-kB-dependent reporter gene expression associated with proliferation, invasion, and motility in aggressive breast cancer phenotypes while decreasing RhoC and RhoA protein expression. CONCLUSION: Inhibition of motility and invasion by PFEs, coincident with suppressed RhoC and RhoA protein expression, suggests a role for these defined extracts in lowering the metastatic potential of aggressive breast cancer species.

Integr Cancer Ther. 2009 Sep;8(3):242-53. PMID: 19815594

241
[+]

Pomegranate juice, total pomegranate ellagitannins, and punicalagin suppress inflammatory cell signaling in colon cancer cells.


Phytochemicals from fruits such as the pomegranate (Punica granatum L) may inhibit cancer cell proliferation and apoptosis through the modulation of cellular transcription factors and signaling proteins. In previous studies, pomegranate juice (PJ) and its ellagitannins inhibited proliferation and induced apoptosis in HT-29 colon cancer cells. The present study examined the effects of PJ on inflammatory cell signaling proteins in the HT-29 human colon cancer cell line. At a concentration of 50 mg/L PJ significantly suppressed TNFalpha-induced COX-2 protein expression by 79% (SE = 0.042), total pomegranate tannin extract (TPT) 55% (SE = 0.049), and punicalagin 48% (SE = 0.022). Additionally, PJ reduced phosphorylation of the p65 subunit and binding to the NFkappaB response element 6.4-fold. TPT suppressed NFkappaB binding 10-fold, punicalagin 3.6-fold, whereas ellagic acid (EA) (another pomegranate polyphenol) was ineffective. PJ also abolished TNFalpha-induced AKT activation, needed for NFkappaB activity. Therefore, the polyphenolic phytochemicals in the pomegranate can play an important role in the modulation of inflammatory cell signaling in colon cancer cells.

J Agric Food Chem. 2006 Feb 8;54(3):980-5. PMID: 16448212

242
[+]

Pomegrante contains compounds with antiproliferative, apoptotic and antioxidant activites against various cancer cell lines.


Pomegranate (Punica granatum L.) fruits are widely consumed as juice (PJ). The potent antioxidant and anti-atherosclerotic activities of PJ are attributed to its polyphenols including punicalagin, the major fruit ellagitannin, and ellagic acid (EA). Punicalagin is the major antioxidant polyphenol ingredient in PJ. Punicalagin, EA, a standardized total pomegranate tannin (TPT) extract and PJ were evaluated for in vitro antiproliferative, apoptotic and antioxidant activities. Punicalagin, EA and TPT were evaluated for antiproliferative activity at 12.5-100 microg/ml on human oral (KB, CAL27), colon (HT-29, HCT116, SW480, SW620) and prostate (RWPE-1, 22Rv1) tumor cells. Punicalagin, EA and TPT were evaluated at 100 microg/ml concentrations for apoptotic effects and at 10 microg/ml concentrations for antioxidant properties. However, to evaluate the synergistic and/or additive contributions from other PJ phytochemicals, PJ was tested at concentrations normalized to deliver equivalent amounts of punicalagin (w/w). Apoptotic effects were evaluated against the HT-29 and HCT116 colon cancer cell lines. Antioxidant effects were evaluated using inhibition of lipid peroxidation and Trolox equivalent antioxidant capacity (TEAC) assays. Pomegranate juice showed greatest antiproliferative activity against all cell lines by inhibiting proliferation from 30% to 100%. At 100 microg/ml, PJ, EA, punicalagin and TPT induced apoptosis in HT-29 colon cells. However, in the HCT116 colon cells, EA, punicalagin and TPT but not PJ induced apoptosis. The trend in antioxidant activity was PJ>TPT>punicalagin>EA. The superior bioactivity of PJ compared to its purified polyphenols illustrated the multifactorial effects and chemical synergy of the action of multiple compounds compared to single purified active ingredients.

J Nutr Biochem. 2005 Jun;16(6):360-7. PMID: 15936648

243
[+]

Resveratrol inhibits human cytomegalovirus replication and virus-induced cellular signaling.


Resveratrol is a polyphenolic natural product that is present in red wine and peanuts and has inhibitory activity against inflammation, heart disease, and cancer. Here we describe its inhibition of human cytomegalovirus replication (IC50 = 1-2 microM). At least 50-fold higher concentrations of compound were required to produce cytotoxicity against growing or stationary human embryonic lung fibroblasts. Mechanism of action studies determined that resveratrol blocked virus-induced activation of the epidermal growth factor receptor (EGFR) and phosphatidylinositol-3-kinase signal transduction as well as NF-kappaB and Sp1 transcription factor activation shortly following infection. Resveratrol prevented the appearance of immediate-early, early, and late viral proteins. Human cytomegalovirus DNA replication was reduced to undetectable levels by treatment with resveratrol, as were the second (late) phases of virus-induced phosphatidylinositol-3-kinase signaling and transcription factor activation. Resveratrol lost substantial antiviral activity when its addition was delayed until 4 h postinfection. Compound reversibility and preincubation studies were inconsistent with a virucidal mechanism of action. These data indicated that this compound likely operated during attachment and entry. We hypothesize that the primary molecular target for resveratrol may be blockage of epidermal growth factor receptor activation and its downstream effectors.

Antiviral Res. 2004 Aug;63(2):85-95. PMID: 15302137

244
[+]

Apples contain a wide range of health benefits.


Apples ( MALUS sp., Rosaceae) are a rich source of nutrient as well as non-nutrient components and contain high levels of polyphenols and other phytochemicals. Main structural classes of apple constituents include hydroxycinnamic acids, dihydrochalcones, flavonols (quercetin glycosides), catechins and oligomeric procyanidins, as well as triterpenoids in apple peel and anthocyanins in red apples. Several lines of evidence suggest that apples and apple products possess a wide range of biological activities which may contribute to health beneficial effects against cardiovascular disease, asthma and pulmonary dysfunction, diabetes, obesity, and cancer (reviewed by Boyer and Liu, Nutr J 2004). The present review will summarize the current knowledge on potential cancer preventive effects of apples, apple juice and apple extracts (jointly designated as apple products). In brief, apple extracts and components, especially oligomeric procyanidins, have been shown to influence multiple mechanisms relevant for cancer prevention in IN VITRO studies. These include antimutagenic activity, modulation of carcinogen metabolism, antioxidant activity, anti-inflammatory mechanisms, modulation of signal transduction pathways, antiproliferative and apoptosis-inducing activity, as well as novel mechanisms on epigenetic events and innate immunity. Apple products have been shown to prevent skin, mammary and colon carcinogenesis in animal models. Epidemiological observations indicate that regular consumption of one or more apples a day may reduce the risk for lung and colon cancer.

J Endocrinol. 2011 Mar;208(3):273-83. Epub 2011 Jan 6. PMID: 18855307

245
[+]

Apple may exert its protective effect against colorectal cancer through acting as a histone-deacetylase inhibitor.


OBJECTIVE: Butyrate plays a major role among the short-chained fatty acids formed by the microbial flora of the colon. It is considered to be an important nutrient of the colon mucosa and has been shown to trigger differentiation and apoptosis of colon-derived cells in culture. Inhibition of histone deacetylase (HDAC) seems to play a central role in these effects. Butyrate was thus suggested to act as a chemopreventive metabolite that can prevent the occurrence of colorectal cancer, one of the most abundant types of cancer in Western industrialized countries. Some polymeric carbohydrates such as pectin, resistant to digestion in the small intestine, have been shown to serve as substrates for butyrate formation by the microflora of the colon. METHODS: In this study we investigated fermentation supernatants (FSs) from incubations of human fecal slurry with apple pectin and with polyphenol-rich apple juice extracts (AJEs). RESULTS: We found that FSs from fermentations with pectin were rich in butyrate and very active in HDAC inhibition in nuclear extracts prepared from the colon tumor cell lines HT-29 and Caco-2 and in intact HeLa Mad 38 cells bearing a reporter gene driven by HDAC inhibition. The butyrate levels explained most of the HDAC-inhibitory potency in FSs from pectin-rich fermentations. FSs from fermentations with AJEs showed lower butyrate yields but comparable HDAC inhibition. Combined incubations of pectin with AJEs led to effects similar to those with FSs from incubations with pectin as the only substrate added. These effects could not be explained by a direct HDAC-inhibitory potency of AJEs. Furthermore, the FSs were not cytotoxic at the HDAC-inhibitory concentrations. CONCLUSION: These findings suggest that butyrate is the most relevant HDAC inhibitor formed in fermentations of human fecal slurry with apple pectin, whereas addition of AJEs leads to the formation of butyrate and other, yet unknown, HDAC inhibitors.

Nutrition. 2008 Apr;24(4):366-74. Epub 2008 Feb 11. PMID: 18262392

246
[+]

Curcumin can be considered as a potential chemopreventive candidate against H. pylori-related gastric carcinogenesis.


BACKGROUND: Anomalous expression of activation-induced cytidine deaminase (AID) in Helicobacter pylori-infected gastric epithelial cells has been postulated as one of the key mechanisms in the development of gastric cancer. AID is overexpressed in the cells through nuclear factor (NF)-kappaB activation by H. pylori and hence, inhibition of NF-kappaB pathway can downregulate the expression of AID. Curcumin, a spice-derived polyphenol, is known for its anti-inflammatory activity via NF-kappaB inhibition. Therefore, it was hypothesized that curcumin might suppress AID overexpression via NF-kappaB inhibitory activity in H. pylori-infected gastric epithelial cells. MATERIALS AND METHODS: MKN-28 or MKN-45 cells and H. pylori strain 193C isolated from gastric cancer patient were used for co-culture experiments. Cells were pretreated with or without nonbactericidal concentrations of curcumin. Apoptosis was determined by DNA fragmentation assay. Enzyme-linked immunosorbent assay was performed to evaluate the anti-adhesion activity of curcumin. Real-time polymerase chain reaction was employed to evaluate the expression of AID mRNA. Immunoblot assay was performed for the analysis of AID, NF-kappaB, inhibitors of NF-kappaB (IkappaB), and IkappaB kinase (IKK) complex regulation with or without curcumin. RESULTS: The adhesion of H. pylori to gastric epithelial cells was not inhibited by curcumin pretreatment at nonbactericidal concentrations (

Toxicol In Vitro. 2010 Mar;24(2):460-4. Epub 2009 Oct 13. PMID: 19889077

247
[+]

Resveratrol induces programmed cell death in human glioma cells.


Resveratrol (trans-3,4',5-trihydroxystilbene) is a naturally occurring polyphenolic compound highly enriched in grapes, peanuts, red wine, and a variety of food sources. Resveratrol has antiinflammatory and antioxidant properties, and also has potent anticancer properties. Human glioma U251 cells were used to understand the molecular mechanisms by which resveratrol acts as an anticancer agent, since glioma is a particularly difficult cancer to treat and eradicate. Our data show that resveratrol induces dose- and time-dependent death of U251 cells, as measured by lactate dehydrogenase release and internucleosomal DNA fragmentation assays. Resveratrol induces activation of caspase-3 and increases the cleavage of the downstream caspase substrate, poly(ADP-ribose) polymerase. Resveratrol-induced DNA fragmentation can be completely blocked by either a general caspase inhibitor (Z-VAD-FMK) or a selective caspase-3 inhibitor (Z-DEVD-FMK), but not by a selective caspase-1 inhibitor. Resveratrol induces cytochrome c release from mitochondria to the cytoplasm and activation of caspase-9. Resveratrol also increases expression of proapoptotic Bax and its translocation to the mitochondria. Resveratrol inhibits U251 proliferation, as measured by MTS assay [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt], and induces G0/G1 growth arrest, as determined by flow cytometry. The cyclin-dependent kinase inhibitor, olomoucine, prevents cell cycle progression and resveratrol-induced apoptosis. These results suggest that multiple signaling pathways may underlie the apoptotic death of U251 glioma induced by resveratrol, which warrants further exploration as an anticancer agent in human glioma.

Biol Pharm Bull. 2001 Feb;24(2):151-4. PMID: 15827328

248
[+]

Turmeric contains the compound curcumin which attenuates the deleterius effects of arsenic in human lymphocytes.


Chronic exposure of humans to high concentrations of arsenic in drinking water is associated with skin lesions, peripheral vascular disease, hypertension, blackfoot disease and a high risk of cancer. Arsenic induces single strand breaks, DNA-protein crosslinks and apurinic sites in DNA, which are prerequisites for induction of cancer. Amelioration of such damages with natural compounds could be an effective strategy to combat arsenic toxicity. Curcumin is the active ingredient of turmeric, a common household spice, which is a rich source of polyphenols and this compound has been extensively studied as a chemopreventive agent against many types of cancer. The present study investigates whether curcumin could counteract the DNA damage caused by arsenic as assessed by single cell gel electrophoresis (SCGE) using peripheral blood lymphocytes, from healthy donors. It was observed that DNA damage induced by arsenic could be efficiently reduced by curcumin and the effect was more pronounced when lymphocytes were pre-incubated with curcumin prior to arsenic insult. Arsenic caused DNA damage by generation of reactive oxygen species (ROS) and enhancement of lipid peroxidation levels. Curcumin counteracted the damage by quenching ROS, decreasing the level of lipid peroxidation and increasing the level of phase II detoxification enzymes like catalase, superoxide dismutase and glutathione peroxidase. Curcumin also enhanced the DNA repair activity against arsenic induced damage. The expression of polymerase, a repair enzyme, was found to be highly elevated when arsenite induced damaged cells were allowed to repair in presence of curcumin. Results indicate that curcumin has significant role in confronting the deleterious effect caused by arsenic, which could be an economic mode of arsenic mitigation among rural population in West Bengal, India.

J Clin Biochem Nutr. 2007 Jul;41(1):32-42. PMID: 18392098

249
[+]

Tea polyphenols mitigate arsenic toxicity in human lymphocytes.


The groundwater arsenicals have brought dreadful misery for the people residing in the endemic regions of West Bengal, India. Arsenic-related anomalies include arsenicosis, hyperkera-tosis, gastric complications, liver fibrosis, peripheral neuropathy, and cancer. Some of these diseases have been frequently associated with overproduction of reactive oxygen species that cause DNA damage and improper functioning of body's antioxidant defense mechanism. Natural polyphenols present in tea serve as excellent antioxidants. In the present study, an attempt has been made to elucidate the role of representative polyphenols and extracts of green and black tea in modulating sodium arsenite (As III)-induced DNA damage in normal human lymphocytes. Comet assay was used to detect the DNA damage. Arsenic-induced oxidative stress was measured with generation of reactive oxygen species, lipid peroxidation, and activity of some antioxidant enzymes. Expression of some repair enzymes such as poly(ADP-ribose) polymerase and DNA polymerase beta was measured to assess the effect of tea on DNA repair. Tea afforded efficient reduction of As III-induced DNA damage in human lymphocytes. Tea also quenched the excessive production of reactive oxygen species by arsenic, reduced the elevated levels of lipid peroxidation, and increased the activity of antioxidant enzymes such as catalase, superoxide dismutase, and glutathione peroxidase. Furthermore, tea enhanced recovery of DNA damage, which was indicative of repair as confirmed by unscheduled DNA synthesis and pronounced expression of DNA repair enzyme poly(ADP-ribose) polymerase. It is speculated that the antioxidant potential and repair-inducing capacity of tea might help in combating the severe genotoxic effects induced by arsenic in the human population.

J Environ Pathol Toxicol Oncol. 2007;26(3):207-20. PMID: 18197836

250
[+]

Tea polyphenols mitigate arsenic toxicity in mammalian cells.


The Gangetic plain of West Bengal, India, has been engulfed by a disastrous environmental calamity of arsenic contamination of the ground water. Chronic arsenic toxicity caused by drinking arsenic-contaminated water has been one of the worst health hazards gradually affecting nine districts of West Bengal since the early 1980s. Over and above hyperpigmentation and keratosis,weakness, burning sensation of the eyes, swelling of the legs, liver fibrosis, chronic lung disease, gangrene of the toes, neuropathy, and skin cancer are other manifestations. Induction of cancer is frequently associated with DNA damage, changes in ploidy of cells, and non-random chromosome aberrations. Counteraction of these genotoxic and cytogenetic abnormalities with natural dietary polyphenols could be a useful strategy to combat arsenic-induced DNA damage and thereby cancer. A review of the literature showed that it is the antioxidant property of tea polyphenols that affords protection against various types of cancer. The present study was conducted to investigate whether the extracts of green tea and black tea (Darjeeling and Assam) as well as their polyphenols could ameliorate this arsenic-induced genotoxicity. The normal mammalian cell culture derived from male Chinese hamster lung fibroblast cells (V79) was used as the test system to assess the genotoxicity by micronucleus assay. The results showed that both green tea and black tea extracts have equal potential in modulating the arsenic-induced genotoxicity. This effect was perhaps induced by the constituent polyphenols present in green and black tea. In addition, the repair activity of the damaged cells was enhanced when treated with these tea extracts and their polyphenols. Thus, tea and its polyphenols may have a promising role in counteracting the devastating effects of arsenic.

Prog Brain Res. 2009;175:239-51. PMID: 15715508

251
[+]

Resveratrol protects against dopaminergic cell death


Resveratrol, a naturally occurring polyphenol, exhibits antioxidant, antiaging, and anticancer activity. Resveratrol has also been shown to inhibit tumor initiation, promotion, and progression in a variety of cell culture systems. Earlier, we showed that paraquat, a bipyridyl herbicide, triggers endoplasmic reticulum stress, cell dysfunction, and dopaminergic cell death. Due to its antioxidant activity, we assessed the ability of resveratrol to rescue cells from the toxic effects of paraquat. While resveratrol did not have any protective effect at low concentrations, it triggered endoplasmic reticulum (ER) stress-induced cell death at higher concentrations (50-250 microM). The present study was carried out to determine the mechanism by which resveratrol triggers ER stress and cell death in dopaminergic N27 cells. Our studies demonstrate that resveratrol triggers ER stress and cell dysfunction, caspase activation, p23 cleavage and inhibition of proteasomal activity in dopaminergic N27 cells. While over expression of uncleavable p23 was associated with decreased cell death, downregulation of p23 protein expression by siRNA resulted in enhancement of ER stress-induced cell death triggered by resveratrol indicating a protective role for the small co-chaperone p23 in dopaminergic cell death.

Br J Nutr. 2009 Dec;102(11):1620-8. Epub 2009 Jul 22. PMID: 19145491

252
[+]

The flavonoids apigenin, luteolin, fisetin and quercetin inhibit hypoxia-induced VEGF expression, which is associated with angiogenesis and cancer promotion.


Flavonoids are a group of polyphenolic dietary compounds that have been proposed to possess chemopreventive properties against lung cancer. In this work we analyzed the effect of a group of 20 structurally related flavonoids, including flavones, flavonols and isoflavones, on the production of vascular endothelial growth factor (VEGF) induced by hypoxia in NCI-H157 cells. VEGF is the main regulator of physiological and pathological angiogenesis and is highly stimulated by hypoxia-inducible factor 1 (HIF-1). We found that apigenin, luteolin, fisetin and quercetin inhibited hypoxia-induced VEGF expression in the low micromolar range. Structure-activity relationships demonstrated that flavone derivatives were the most active compounds and that hydroxylation of the A-ring at the 5 and 7 positions and of the B ring at the 4' position were important for this activity. Interestingly, only a group of VEGF inhibitors, including apigenin, flavone and 4',7-dihydroxiflavone, reduced the expression of HIF-1alpha under these conditions, whereas others, such as fisetin, luteolin, galangin or quercetin, induced HIF-1alpha expression while reducing those of VEGF. When cells were exposed to hypoxia in the presence of these flavonoids, HIF-1alpha translocated to the nucleus and interacted with p300/CBP, but this complex was transcriptionally inactive. Taken together these findings indicate that flavonoids impair VEGF transcription by an alternative mechanism that did not depend on nuclear HIF levels. We also found that flavonoids suppressed hypoxia-induced STAT3 tyrosine phosphorylation and that this activity correlated with their potency as VEGF inhibitors, suggesting that inhibition of STAT3 function may play a role in this process.

Biochem Pharmacol. 2010 Feb 10. Epub 2010 Feb 10. PMID: 20153296

253
[+]

Apigenin induces programmed cell death in human breast cancer cells.


Apigenin is a low toxicity and non-mutagenic phytopolyphenol and protein kinase inhibitor. It exhibits anti-proliferating effects on human breast cancer cells. Here we examined several human breast cancer cell lines having different levels of HER2/neu expression and found that apigenin exhibited potent growth-inhibitory activity in HER2/neu-overexpressing breast cancer cells but was much less effective for those cells expressing basal levels of HER2/neu. Induction of apoptosis was also observed in HER2/neu-overexpressing breast cancer cells in a dose- and time-dependent manner. However, the one or more molecular mechanisms of apigenin-induced apoptosis in HER2/neu-overexpressing breast cancer cells remained to be elucidated. A cell survival pathway involving phosphatidylinositol 3-kinase (PI3K), and Akt is known to play an important role in inhibiting apoptosis in response to HER2/neu-overexpressing breast cancer cells, which prompted us to investigate whether this pathway plays a role in apigenin-induced apoptosis in HER2/neu-overexpressing breast cancer cells. Our results showed that apigenin inhibits Akt function in tumor cells in a complex manner. First, apigenin directly inhibited the PI3K activity while indirectly inhibiting the Akt kinase activity. Second, inhibition of HER2/neu autophosphorylation and transphosphorylation resulting from depleting HER2/neu protein in vivo was also observed. In addition, apigenin inhibited Akt kinase activity by preventing the docking of PI3K to HER2/HER3 heterodimers. Therefore, we proposed that apigenin-induced cellular effects result from loss of HER2/neu and HER3 expression with subsequent inactivation of PI3K and AKT in cells that are dependent on this pathway for cell proliferation and inhibition of apoptosis. This implies that the inhibition of the HER2/HER3 heterodimer function provided an especially effective strategy for blocking the HER2/neu-mediated transformation of breast cancer cells. Our results also demonstrated that apigenin dissociated the complex of HER2/neu and GRP94 that preceded the depletion of HER2/neu. Apigenin-induced degradation of mature HER2/neu involves polyubiquitination of HER2/neu and subsequent hydrolysis by the proteasome.

J Biol Chem. 2004 Feb 6;279(6):4479-89. Epub 2003 Nov 5. PMID: 14602723

254
[+]

The dietary flavonoids ECGC, luteolin, quercetin, kaempferol, apigenin, and taxifolin inhibit cancer cell lipogenesis.


The consumption of food products containing high amounts of flavonoids has been reported to lower the risk of various cancers. The mechanisms underlying the cancer-protective effects of these naturally occurring polyphenolic compounds, however, remain elusive. Based on our previous finding that the cytotoxic effect of the flavanol epigallocatechin-3-gallate on prostate cancer cells correlates with its ability to inhibit fatty acid synthase (FAS, a key lipogenic enzyme overexpressed in many human cancers), we examined the anti-lipogenic effects of a panel of 18 naturally occurring polyphenolic compounds. In addition to epigallocatechin-3-gallate, five other flavonoids, more particularly luteolin, quercetin, kaempferol, apigenin, and taxifolin, also markedly inhibited cancer cell lipogenesis. Interestingly, in both prostate and breast cancer cells, a remarkable dose-response parallelism was observed between flavonoid-induced inhibition of fatty acid synthesis, inhibition of cell growth, and induction of apoptosis. In support for a role of fatty acid synthesis in these effects, the addition of exogenous palmitate, the end product of FAS, markedly suppressed the cytotoxic effects of flavonoids. Taken together, these findings indicate that the potential of flavonoids to induce apoptosis in cancer cells is strongly associated with their FAS inhibitory properties, thereby providing a new mechanism by which polyphenolic compounds may exert their cancer-preventive and antineoplastic effects.

J Biol Chem. 2005 Feb 18;280(7):5636-45. Epub 2004 Nov 8. PMID: 15533929

255
[+]

EGCG is a potent natural inhibitor of fatty acid synthase in intact cells and selectively induces apoptosis in prostate cancer cells.


Chemical inhibitors of fatty acid synthase (FAS) inhibit growth and induce apoptosis in several cancer cell lines in vitro and in tumor xenografts in vivo. Recently the green tea component epigallocatechin-3-gallate (EGCG) was shown to act as a natural inhibitor of FAS in chicken liver extracts. Here we investigated whether EGCG inhibits FAS activity in cultured prostate cancer cells and how this inhibition affects endogenous lipid synthesis, cell proliferation and cell viability. The high levels of FAS activity in LNCaP cells were dose-dependently inhibited by EGCG and this inhibition was paralleled by decreased endogenous lipid synthesis, inhibition of cell growth and induction of apoptosis. In contrast, epicatechin (EC), another closely related green tea polyphenolic compound, which does not inhibit FAS, had no effect on LNCaP cell growth or viability. Treatment of nonmalignant cells with low levels of FAS activity (fibroblasts) with EGCG led to a decrease in growth rate but not to induction of apoptosis. These data indicate that EGCG inhibits FAS activity as efficiently as presently known synthetic inhibitors and selectively causes apoptosis in LNCaP cells but not in nontumoral fibroblasts. These findings establish EGCG as a potent natural inhibitor of FAS in intact cells and strengthen the molecular basis for the use of EGCG as a chemopreventive and therapeutic antineoplastic agent.

Cancer Immunol Immunother. 2010 Feb 6. Epub 2010 Feb 6. PMID: 12918062

256
[+]

EGCG inhibits growth, disrupts the cell cycle and induces programmed cell death in androgen-sensitive and androgen-insensitive human prostate cancer cells.


Prostate cancer (PCA) is the most prevalent cancer diagnosed and the second leading cause of cancer-related deaths among men in the United States. Descriptive epidemiological data suggest that androgens and environmental exposures play a key role in prostatic carcinogenesis. Since androgen action is intimately associated with proliferation and differentiation, at the time of clinical diagnosis in humans most PCA represent themselves as a mixture of androgen-sensitive and androgen-insensitive cells. Androgen-sensitive cells undergo rapid apoptosis upon androgen withdrawal. On the other hand, the androgen-insensitive cells do not undergo apoptosis upon androgen blocking, but maintain the molecular machinery of apoptosis. Thus, agents capable of inhibiting growth and/or inducing apoptosis in both androgen-sensitive and androgen-insensitive cells will be useful for the management of PCA. In the present study, we show that (-)-epigallocatechin-3-gallate (EGCG), the major polyphenolic constituent present in green tea, imparts antiproliferative effects against both androgen-sensitive and androgen-insensitive human PCA cells, and this effect is mediated by deregulation in cell cycle and induction of apoptosis. EGCG treatment was found to result in a dose-dependent inhibition of cell growth in both androgen-insensitive DU145 and androgen-sensitive LNCaP cells. In both the cell types, EGCG treatment also resulted in a dose-dependent G(0)/G(1)-phase arrest of the cell cycle as observed by DNA cell-cycle analysis. As evident by DNA ladder assay, confocal microscopy, and flow cytometry, the treatment of both DU145 and LNCaP cells with EGCG resulted in a dose-dependent apoptosis. Western blot analysis revealed that EGCG treatment resulted in (i) a dose-dependent increase of p53 in LNCaP cells (carrying wild-type p53), but not in DU145 cells (carrying mutant p53), and (ii) induction of cyclin kinase inhibitor WAF1/p21 in both cell types. These results suggest that EGCG negatively modulates PCA cell growth, by affecting mitogenesis as well as inducing apoptosis, in cell-type-specific manner which may be mediated by WAF1/p21-caused G(0)/G(1)-phase cell-cycle arrest, irrespective of the androgen association or p53 status of the cells.

Toxicol Appl Pharmacol. 2000 Apr 1;164(1):82-90. PMID: 10739747

257
[+]

Extra-virgin olive oil polyphenols may inhibit breast cancer through interfering with fatty acid synthesis.


Inhibitors of fatty acid synthase (FASN), a key enzyme involved in the anabolic conversion of dietary carbohydrates to fat in mammals, are receiving increasingly more attention as they may provide therapeutic moieties for the treatment of human malignancies. Natural compounds, such as the green tea polyphenol epigallocatechin-3-gallate, have been shown to induce anti-cancer effects by suppressing FASN, which may account for the epidemiologically observed inverse correlation between green-tea drinking and cancer risk in Oriental populations. Since extra-virgin olive oil (EVOO)-derived phenolics have been suggested to possess biological activities that may explain the health-promoting effects of the 'Mediterranean diet', we evaluated their effects on the expression of FASN protein in human breast epithelial cell lines. First, we developed a reverse phase protein microspot array (RPPA) capable of rapidly assessing the relative amount of FASN protein in whole lysates from cultured human cells. Then we tested the effects of phenolic fractions from EVOO and its main constituents including single phenols (i.e. tyrosol, hydroxytyrosol, vanillin), phenolic acids (i.e. caffeic acid, p-coumaric acid, vanillic acid, ferulic acid, elenolic acid), lignans (i.e. 1-[+]-pinoresinol, 1-[+]-acetoxy-pinoresinol), flavonoids (i.e. apigenin, luteolin), or secoiridoids (i.e. deacetoxyoleuropein aglycone, ligstroside aglycone, oleuropein glycoside, oleuropein aglycone) on FASN protein expression. EVOO polyphenols lignans, flavonoids and secoiridoids were found to drastically suppress FASN protein expression in HER2 gene-amplified SKBR3 breast cancer cells. Equivalent results were observed in MCF-7 cells engineered to overexpress the HER2 tyrosine kinase receptor, a well-characterized up-regulator of FASN expression in aggressive sub-types of cancer cells. EVOO-derived lignans, flavonoids and secoiridoids were significantly more effective than the mono-HER2 inhibitor trastuzumab ( approximately 50% reduction) and as effective as the dual HER1/HER2 tyrosine kinase inhibitor lapatinib (>or =95% reduction) at suppressing high-levels of FASN protein in HER2-overexpressing SKBR3 and MCF-7/HER2 cells. EVOO single phenols and phenolic acids failed to modulate FASN expression in SKBR3 and MCF-7/HER2 cells. These findings reveal for the first time that phenolic fractions, directly extracted from EVOO, may induce anti-cancer effects by suppressing the expression of the lipogenic enzyme FASN in HER2-overexpressing breast carcinoma cells, thus offering a previously unrecognized mechanism for EVOO-related cancer preventive effects.

Clin Nutr. 2009 Feb;28(1):34-8. Epub 2008 Nov 29. PMID: 18813848

258
[+]

Diosmetin inhibits cell cycle progression and proliferation in breast cancer cells.


Flavonoids constitute a large class of polyphenolic compounds with cancer preventative properties. We have examined the ability of the natural flavone diosmetin to inhibit proliferation of breast adenocarcinoma MDA-MB 468 and normal breast MCF-10A cells and found that this compound is selective for the cancer cells with slight toxicity in the normal breast cells. Diosmetin was metabolised to the structurally similar flavone luteolin in MDA-MB 468 cells, whereas no metabolism was seen in MCF-10A cells. Diosmetin caused G1 arrest at 10 microM in MDA-MB 468 cells after 48-h treatment whereas this effect was not observed in MCF-10A cells. We suggest that diosmetin exerts cytostatic effects in MDA-MB 468 cells, due to CYP1A1 and CYP1B1 catalyzed conversion to the flavone luteolin.

Oncol Rep. 2009 Jun;21(6):1525-8. PMID: 19424633

259
[+]

Luteolin encourages programmed cell death in lung cancer cells.


Nuclear factor kappaB (NF-kappaB) activated by tumor necrosis factor (TNF) attenuates the TNF-induced apoptosis pathway. Therefore, blockage of NF-kappaB should improve the anticancer activity of TNF. Luteolin, a naturally occurring polyphenol flavonoid, has been reported to sensitize colorectal cancer cells to TNF-induced apoptosis through suppression of NF-kappaB; however, the mechanisms of this effect have not been well elucidated. In this article, we provide evidence showing a critical role of reactive oxygen species (ROS) accumulation induced by luteolin in modulating TNF-activated pathways in lung cancer cells. Luteolin effectively suppressed NF-kappaB, whereas it potentiated the c-Jun N-terminal kinase (JNK) to increase apoptosis induced by TNF in lung cancer cells. Our results further demonstrate that luteolin induced an early phase ROS accumulation via suppression of the cellular superoxide dismutase activity. It is noteworthy that suppression of ROS accumulation by ROS scavengers butylated hydroxyanisole, and N-acetyl-L-cysteine prevented the luteolin-induced suppression of NF-kappaB and potentiation of JNK and significantly suppressed the synergistic cytotoxicity seen with cotreatment of luteolin and TNF. Taken together, these results suggest that the accumulation of ROS induced by luteolin plays a pivotal role in suppression of NF-kappaB and potentiation of JNK to sensitize lung cancer cells to undergo TNF-induced apoptosis.

Mol Pharmacol. 2007 May;71(5):1381-8. Epub 2007 Feb 12. PMID: 17296806

260
[+]

Oleuropein and hydroxytyrosol, two polyphenols contianed within extra-virgin olive oil, inhibit MCF-7 breast cancer cell proliferation.


The growth of many breast tumors is stimulated by estradiol (E2), which activates a classic mechanism of regulation of gene expression and signal transduction pathways inducing cell proliferation. Polyphenols of natural origin with chemical similarity to estrogen have been shown to interfere with tumor cell proliferation. The aim of this study was to investigate whether hydroxytyrosol (HT) and oleuropein (OL), two polyphenols contained in extra-virgin olive oil, can affect breast cancer cell proliferation interfering with E2-induced molecular mechanisms. Both HT and OL inhibited proliferation of MCF-7 breast cancer cells. Luciferase gene reporter experiments, using a construct containing estrogen responsive elements able to bind estrogen receptor alpha (ERalpha) and the study of the effects of HT or OL on ERalpha expression, demonstrated that HT and OL are not involved in ERalpha-mediated regulation of gene expression. However, further experiments pointed out that both OL and HT determined a clear inhibition of E2-dependent activation of extracellular regulated kinase1/2 belonging to the mitogen activating protein kinase family. Our study demonstrated that HT and OL can have a chemo-preventive role in breast cancer cell proliferation through the inhibition of estrogen-dependent rapid signals involved in uncontrolled tumor cell growth.

Mol Nutr Food Res. 2009 Dec 10. PMID: 20013881

261
[+]

Gicomo Castelvetro's philosophy of nutrition, e.g. (i.e., "raw vegetables... plenty of generous (olive) oil"), may be protect women against breast cancer.


We are accumulating evidence to suggest that 17(th) century Renaissance foodways -largely based on the old "Mediterranean dietary traditions"- may provide new nutraceutical management strategies against HER2-positive breast cancer disease in the 21st century. Epidemiological and experimental studies begin to support the notion that "The Sacred Law of Salads" (i.e., "raw vegetables... plenty of generous (olive) oil") -originally proposed in 1614 by Giacomo Castelvetro in its book The Fruit, Herbs&Vegetables of Italy- might be considered the first (unintended) example of customised diets for breast cancer prevention based on individual genetic make-up (i.e., nutraceuticals against human breast carcinomas bearing HER2 oncogene amplification/overexpression). First, the so-called salad vegetables dietary pattern (i.e., a high consumption of raw vegetables and olive oil) appears to exert a protective effect mostly confined to the HER2-positive breast cancer subtype, with no significant influence on the occurrence of HER2-negative breast cancers. Second, all the main olive oil constituents (i.e., the omega-9 monounsaturated fatty acid oleic acid and polyphenolic compounds such as the secoiridoid oleuropein or the lignan 1-[+]-acetoxypinoresinol) dramatically reduce HER2 expression and specifically induce apoptotic cell death in cultured HER2- positive breast cancer cells, with marginal effects against HER2-negative cells. Third, an olive oil-rich diet negatively influences experimental mammary tumorigenesis in rats likewise decreasing HER2 expression levels. If early 1600s Castelvetro's salads can be used as dietary protocols capable to protecting women against biologically aggressive HER2-positive breast cancer subtypes is an intriguing prospect that warrants to be evaluated in human pilot studies in the future. Here, at least, we would like to recognise Giacomo Castelvetro as the father of modern nutritional genomics in oncology.

Clin Transl Oncol. 2008 Jan;10(1):30-4. PMID: 18208790

262
[+]

Oleuropein profoundly increases the susceptibility of breast cancer cells to trastuzumab treatment.


BACKGROUND: A low incidence of breast cancer in the Mediterranean basin suggests that a high consumption of Extra Virgin Olive Oil (EVOO) might confer this benefit. While the anti-HER2 oncogene effects of the main omega-9 fatty acid present in EVOO triacylglycerols (i.e., oleic acid) have been recently described, the anti-breast cancer activities of EVOO non-glyceridic constituents--which consist of at least 30 phenolic compounds--remained to be evaluated. METHODS: Semi-preparative HPLC was used to isolate EVOO polyphenols (i.e., tyrosol, hydroxytyrosol, oleuropein). Both the anti-proliferative and the pro-apoptotic effects of EVOO phenolics were evaluated by using MTT-based quantification of metabolically viable cells and ELISA-based detection of histone-associated DNA fragments, respectively. The nature of the interaction between oleuropein aglycone and the anti-HER2 monoclonal antibody trastuzumab (Herceptin) was mathematically evaluated by the dose-oriented isobologram technique. HER2-specific ELISAs were employed to quantitatively assess both the basal cleavage of the HER2 extracellular domain (ECD) and the expression level of total HER2. The activation status of HER2 was evaluated by immunoblotting procedures using a monoclonal antibody specifically recognizing the tyrosine phosphorylated (Phosphor-Tyr1248) form of HER2. RESULTS: Among EVOO polyphenols tested, oleuropein aglycone was the most potent EVOO phenolic in decreasing breast cancer cell viability. HER2 gene-amplified SKBR3 cells were ~5-times more sensitive to oleuropein aglycone than HER2-negative MCF-7 cells. Retroviral infection of the HER2 oncogene in MCF-7 cells resulted in a "SKBR3-assimilated" phenotype of hypersensitivity to oleuropein aglycone. An up to 50-fold increase in the efficacy of trastuzumab occurred in the presence of oleuropein aglycone. A preclinical model of acquired autoresistance to trastuzumab (SKBR3/Tzb100 cells) completely recovered trastuzumab sensitivity (>1,000-fold sensitization) when co-cultured in the presence of oleuropein aglycone. Indeed, the nature of the interaction between oleuropein aglycone and trastuzumab was found to be strongly synergistic in Tzb-resistant SKBR3/Tzb100 cells. Mechanistically, oleuropein aglycone treatment significantly reduced HER2 ECD cleavage and subsequent HER2 auto-phosphorylation, while it dramatically enhanced Tzb-induced down-regulation of HER2 expression. CONCLUSION: Olive oil's bitter principle (i.e., oleuropein aglycone) is among the first examples of how selected nutrients from an EVOO-rich "Mediterranean diet" directly regulate HER2-driven breast cancer disease.

BMC Cancer. 2007;7:80. Epub 2007 May 9. PMID: 17490486

263
[+]

Olive oil polyphenols inhibit human colon cancer cell proliferation.


We investigated the anti-proliferative effects of an olive oil polyphenolic extract on human colon adenocarcinoma cells. Analysis indicated that the extract contained hydroxytyrosol, tyrosol and the various secoiridoid derivatives, including oleuropein. This extract exerted a strong inhibitory effect on cancer cell proliferation, which was linked to the induction of a G2/M phase cell cycle block. Following treatment with the extract (50 microg/ml) the number of cells in the G2/M phase increased to 51.82+/-2.69% relative to control cells (15.1+/-2.5%). This G2/M block was mediated by the ability of olive oil polyphenols (50 microg/ml) to exert rapid inhibition of p38 (38.7+/-4.7%) and CREB (28.6+/-5.5%) phosphorylation which led to a downstream reduction in COX-2 expression (56.9+/-9.3%). Our data suggest that olive oil polyphenols may exert chemopreventative effects in the large intestine by interacting with signalling pathways responsible for colorectal cancer development.

Biochem Biophys Res Commun. 2007 Oct 26;362(3):606-11. Epub 2007 Aug 17. PMID: 17727817

264
[+]

Curcumin induces programmed cell death in Leishmania through its pro-oxidant and calcium-modulating activity.


Curcumin, a polyphenol compound, has been recognized as a promising anti-cancer drug. The purpose of the present study was to investigate the cytotoxicity of curcumin to Leishmania donovani, the causative agent for visceral leishmaniasis. Flow cytometric analysis revealed that curcumin induced cell cycle arrest at G2/M phase. Incubation of Leishmania promastigotes with curcumin caused exposure of phosphatidylserine to the outer leaflet of plasma membrane. This event is preceded by curcumin-induced formation of reactive oxygen species (ROS) and elevation of cytosolic calcium through the release of calcium ions from intracellular stores as well as by influx of extracellular calcium. Elevation of cytosolic calcium is responsible for depolarization of mitochondrial membrane potential (DeltaPsim), release of Cytochrome c into the cytosol and concomitant nuclear alterations that included deoxynucleotidyltransferase-mediated dUTP end labeling (TUNEL) and DNA fragmentation. Taken together, these data indicate that curcumin has promising antileishmanial activity that is mediated by programmed cell death and, accordingly, merits further investigation as a therapeutic option for the treatment of leishmaniasis.

Apoptosis. 2008 Jul;13(7):867-82. PMID: 18506627

265
[+]

EGCG sensitizes human cholangiocarcinoma cells to chemotherapy-induced programmed cell death.


BACKGROUND: Green tea polyphenols are chemopreventive in several cancer models but their use as adjunctive therapeutic agents for cancer is unknown. AIMS: Cholangiocarcinomas respond poorly to chemotherapeutic agents and our aims were to assess the utility of green tea polyphenols as adjuncts to chemotherapy for cholangiocarcinoma. MATERIALS AND METHODS: We assessed the effect of purified green tea catechins on chemotherapy-induced apoptosis in KMCH, CC-LP-1 and Mz-ChA-1 human cholangiocarcinoma cells, and on chemosensitivity of Mz-ChA-1 cell xenografts in nude mice. RESULTS: Epigallocatechin-gallate (EGCG), but not the structurally related catechin epigallocatechin, sensitized cells to apoptosis induced by gemcitabine (GEM), mitomycin C or 5-fluorouracil in vitro. Mitochondrial membrane depolarization, cytosolic cytochrome c expression and apoptosis were increased in cells incubated with EGCG and GEM compared with either agent alone. Furthermore, EGCG decreased in vivo growth and increased the sensitivity to GEM of Mz-ChA-1 cell xenografts in nude mice. CONCLUSIONS: The green tea polyphenol EGCG sensitizes human cholangiocarcinoma cells to chemotherapy-induced apoptosis and warrants evaluation as an adjunct to chemotherapy for the treatment of human cholangiocarcinoma.

Liver Int. 2009 May;29(5):670-7. Epub 2009 Feb 17. PMID: 19226332

266
[+]

Curcumin induces programmed cell death in chronic myeloid leukemia cells.


Curcumin (1), a natural polyphenolic compound, has shown strong antioxidant and anticancer activities. Several molecular mechanisms have been attributed to its inhibitory effects on a wide range of tumor cells. In this study, the response of the chronic myeloid leukemia cell line K562 cells to 1 is investigated. Curcumin inhibited the viability of K562 cells in a dose- and time-dependent manner. Furthermore, curcumin-induced cell death was associated with the formation of the apoptosome complex, the collapse of the mitochondrial membrane potential, and caspase-3 activation. Curcumin treatment also induced Bid cleavage and downregulated the expression of Bcl-2 protein. Surprisingly, even with these molecular features of apoptosis, we showed that 1 stimulated autophagy, which was evidenced by microtubule-associated protein light chain 3 (LC3) immunoreactivty. Curcumin also increased the protein levels of beclin 1 and membrane form LC3 (LC3-II). Autophagy inhibitor bafilomycin A1 and the pan-caspase inhibitor Z-VAD-fmk suppressed curcumin-induced K562 cell death. Overall, these results suggest that curcumin induces autophagic and apoptotic death of K562 cells. These findings suggest that both apoptotic and autophagic mechanisms contribute to the curcumin-induced K562 cell death.

J Asian Nat Prod Res. 2009 Nov;11(11):918-28. PMID: 20183254

267
[+]

EGCG inhibits lung cancer cell growth.


(-)-Epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, has been shown to inhibit tumorigenesis and cancer cell growth in animal models. Nevertheless, the dose-response relationship of the inhibitory activity in vivo has not been systematically characterized. The present studies were conducted to address these issues, as well as the involvement of reactive oxygen species (ROS), in the inhibitory action of EGCG in vivo and in vitro. We characterized the inhibitory actions of EGCG against human lung cancer H1299 cells in culture and in xenograft tumors. The growth of tumors was dose-dependently inhibited by EGCG at doses of 0.1%, 0.3% and 0.5% in the diet. Tumor cell apoptosis and oxidative DNA damage, assessed by the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and phosphorylated histone 2A variant X (gamma-H2AX), were dose-dependently increased by EGCG treatment. However, the levels of 8-OHdG and gamma-H2AX were not changed by the EGCG treatment in host organs. In culture, the growth of viable H1299 cells was dose-dependently reduced by EGCG; the estimated IC(50) (20 muM) was much higher than the IC(50) (0.15 muM) observed in vivo. The action of EGCG was mostly abolished by the presence of superoxide dismutase (SOD) and catalase, which decompose the ROS formed in the culture medium. Treatment with EGCG also caused the generation of intracellular ROS and mitochondrial ROS. Although EGCG is generally considered to be an antioxidant, the present study demonstrates the pro-oxidative activities of EGCG in vivo and in vitro in the described experimental system.

Carcinogenesis. 2010 Feb 16. Epub 2010 Feb 16. PMID: 20159951

268
[+]

Resveratrol has therapeutic potential for age-associated chronic diseases.


Extensive research within the last decade has revealed that most chronic illnesses such as cancer, cardiovascular and pulmonary diseases, neurological diseases, diabetes, and autoimmune diseases exhibit dysregulation of multiple cell signaling pathways that have been linked to inflammation. Thus mono-targeted therapies developed for the last two decades for these diseases have proven to be unsafe, ineffective and expensive. Although fruits and vegetables are regarded to have therapeutic potential against chronic illnesses, neither their active component nor the mechanism of action is well understood. Resveratrol (trans-3, 5, 4'-trihydroxystilbene), a component of grapes, berries, peanuts and other traditional medicines, is one such polyphenol that has been shown to mediate its effects through modulation of many different pathways. This stilbene has been shown to bind to numerous cell-signaling molecules such as multi drug resistance protein, topoisomerase II, aromatase, DNA polymerase, estrogen receptors, tubulin and F1-ATPase. Resveratrol has also been shown to activate various transcription factor (e.g; NFkappaB, STAT3, HIF-1alpha, beta-catenin and PPAR-gamma), suppress the expression of antiapoptotic gene products (e.g; Bcl-2, Bcl-X(L), XIAP and survivin), inhibit protein kinases (e.g; src, PI3K, JNK, and AKT), induce antioxidant enzymes (e,g; catalase, superoxide dismutase and hemoxygenase-1), suppress the expression of inflammatory biomarkers (e.g., TNF, COX-2, iNOS, and CRP), inhibit the expression of angiogenic and metastatic gene products (e.g., MMPs, VEGF, cathepsin D, and ICAM-1), and modulate cell cycle regulatory genes (e.g., p53, Rb, PTEN, cyclins and CDKs). Numerous animal studies have demonstrated that this polyphenol holds promise against numerous age-associated diseases including cancer, diabetes, Alzheimer, cardiovascular and pulmonary diseases. In view of these studies, resveratrol's prospects for use in the clinics are rapidly accelerating. Efforts are also underway to improve its activity in vivo through structural modification and reformulation. Our review describes various targets of resveratrol and their therapeutic potential.

Cell Cycle. 2008 Apr 15;7(8):1020-35. Epub 2008 Feb 15. PMID: 18414053

269
[+]

Resveratrol may be a suitable adjuvant to radioiodide therapy in treating thyroid cancer.


BACKGROUND: Resveratrol, a polyphenol found in grapes, exhibits several beneficial health effects by its antioxidant, antiinflammatory, and chemopreventive properties. The aim of the present study was to determine the effect of resveratrol on iodide trapping and efflux as well as its mode of action using FRTL-5 cells, having in mind the pivotal role of the natrium iodide symporter (NIS) in the treatment of differentiated thyroid cancers. METHODS: Cells were treated with resveratrol for various times and doses, in the presence or absence of thyrotropin (TSH). Iodide trapping, iodide efflux, rat NIS (rNIS) protein expression, and cyclic AMP (cAMP) production were evaluated. RESULTS: Resveratrol increased iodide trapping in a time-dependent (optimal 6 hours) and dose-dependent (100 microM) way in the presence of TSH. It showed an additive effect when concomitantly added with an optimal dose of TSH. Resveratrol (50 microM) increased (threefold) rNIS protein expression. In TSH-deprived cells, resveratrol also provoked an increase in rNIS protein (>3-fold in 6 hours) with an optimum at 40 microM. Resveratrol did not inhibit iodide efflux from FRTL-5 cells. It neither increased intracellular cAMP nor induced the arborization of living cells, two TSH-induced effects. A non-cAMP mode of action is highly suspected. CONCLUSIONS: Resveratrol increases iodide trapping in FRTL-5 cells, increasing iodide influx and rNIS protein level even in the absence of TSH. It has an additive effect with TSH. Consequently, resveratrol could be a promising molecule for radioiodide therapy in follicular and papillary differentiated thyroid carcinoma in association with recombinant human TSH.

Thyroid. 2010 Feb;20(2):195-203. PMID: 20151827

270
[+]

Theaflavins from black tea selectively inhibit SV40-transformed cancer cells.


Theaflavin (TF-1), theaflavin-3-monogallate and theaflavin-3'-monogallate mixture (TF-2), and theaflavin-3,3'-digallate (TF-3) are the major black tea polyphenols. Here we compared the effects of these polyphenols on cell growth, apoptosis, and gene expression in normal and cancerous cells. We showed that TF-2 (10-50 microM) inhibited the growth of SV40 transformed WI38 human cells (WI38VA) and Caco-2 colon cancer cells but had little effect on the growth of their normal counterparts. The IC50s of TF-2 for the growth inhibition of WI38 and WI38VA cells were, respectively, 300 and 3 microM. The other two black tea polyphenols, TF-1 and TF-3, did not exhibit such differential growth-inhibitory effect. TF-2, but not TF-1 or TF-3, induced apoptosis in transformed WI38VA cells but not in normal WI38 cells, suggesting that apoptosis was responsible, at least in part, for the differential growth-inhibitory effect of TF-2. Cox-2 has been implicated in intestinal carcinogenesis. Among the tea polyphenols tested, TF-2 and, to a lesser degree, (-)-epigallocatechin gallate inhibited cyclooxygenase (Cox)-2 gene expression. TF-2 at 50 microM completely blocked the serum-induced Cox-2 gene expression at both mRNA and protein level. Other genes, including c-fos, c-myc, thymidine kinase, proliferating cell nuclear antigen, BRCA1, BRCA2, and Cox-1, were not significantly affected by TF-2. These findings suggest that TF-2 may be responsible, at least in part, for the chemopreventive activity in black tea extracts.

Cancer Res. 2000 Nov 15;60(22):6465-71. PMID: 11103814

271
[+]

Green tea polyphenols reduce skin tumor cell survival.


The polycomb group (PcG) proteins are epigenetic regulators of gene expression that enhance cell survival. This regulation is achieved via action of two multiprotein PcG complexes--PRC2 (EED) and PRC1 [B-cell-specific Moloney murine leukemia virus integration site 1 (Bmi-1)]. These complexes modulate gene expression by increasing histone methylation and reducing acetylation--leading to a closed chromatin conformation. Activity of these proteins is associated with increased cell proliferation and survival. We show increased expression of key PcG proteins in immortalized keratinocytes and skin cancer cell lines. We examine the role of two key PcG proteins, Bmi-1 and enhancer of zeste homolog 2 (Ezh2), and the impact of the active agent in green tea, (-)-epigallocatechin-3-gallate (EGCG), on the function of these regulators. EGCG treatment of SCC-13 cells reduces Bmi-1 and Ezh2 level and this is associated with reduced cell survival. The reduction in survival is associated with a global reduction in histone H3 lysine 27 trimethylation, a hallmark of PRC2 complex action. This change in PcG protein expression is associated with reduced expression of key proteins that enhance progression through the cell cycle [cyclin-dependent kinase (cdk)1, cdk2, cdk4, cyclin D1, cyclin E, cyclin A and cyclin B1] and increased expression of proteins that inhibit cell cycle progression (p21 and p27). Apoptosis is also enhanced, as evidenced by increased caspase 9, 8 and 3 cleavage and increased poly(adenosine diphosphate ribose) polymerase cleavage. EGCG treatment also increases Bax and suppresses Bcl-xL expression. Vector-mediated enhanced Bmi-1 expression reverses these EGCG-dependent changes. These findings suggest that green tea polyphenols reduce skin tumor cell survival by influencing PcG-mediated epigenetic regulatory mechanisms.

Carcinogenesis. 2010 Mar;31(3):496-503. Epub 2009 Dec 16. PMID: 20015867

272
[+]

Edible seaweed has antixoidant and antiproliferative activity against cervical cancer cell lines.


Dietary Laminaria and Porphyra sp. have been reported to reduce the risk of intestinal or mammary cancer in animal studies. Algal anticarcinogenicity may involve effects on cell proliferation and antioxidant activity. Thus, in the present study, we evaluated the effect of red alga, dulse (Palmaria palmata) and three kelp (Laminaria setchellii, Macrocystis integrifolia, Nereocystis leutkeana) extracts on human cervical adenocarcinoma cell line (HeLa cells) proliferation using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The 1-butanol soluble fractions from the methanol extracts of these algae were also evaluated for reducing activity and total polyphenol content. After 72 h incubation, HeLa cell proliferation was inhibited (pM. integrifolia>L. setchellii>N. leutkeana; and total polyphenol contents were: P. palmata>M. integrifolia=N. leutkeana>L. setchellii. The antiproliferative efficacy of these algal extracts were positively correlated with the total polyphenol contents (p

Food Chem Toxicol. 2006 Jul;44(7):1144-50. Epub 2006 Mar 22. PMID: 16554116

273
[+]

Rambutan and coconut peel have significant antioxidant and antiproliferative activities.


The aim of this study was to evaluate antioxidant activity and cytotoxicity against human cell lines of fruit peel extracts from rambutan, mangosteen and coconut. The highest antioxidant activity was found from rambutan peel crude extract where the highest radical scavenging capacity via ABTS assay was from its ethyl acetate fraction with a TEAC value of 23.0mM/mg and the highest ferric ion reduction activity via FRAP assay was from its methanol fraction with an EC value of 20.2mM/mg. Importantly, using both assays, these fractions had a higher antioxidant activity than butylated hydroxyl toluene and vitamin E. It was shown that the ethyl acetate fraction of rambutan peel had the highest polyphenolic content with a gallic acid equivalent of 2.3mg/mL. The results indicate that the polyphenolic compounds are responsible for the observed antioxidant activity of the extracts. Interestingly, the hexane fraction of coconut peel showed a potent cytotoxic effect on KB cell line by MTT assay (IC(50)=7.7 microg/mL), and no detectable cytotoxicity toward normal cells. We concluded that the ethyl acetate fraction of rambutan peel is a promising resource for potential novel antioxidant agents whereas the hexane fraction of coconut peel may contain novel anticancer compounds.

J Periodontol. 2009 Feb;80(2):317-23. PMID: 20510336

274
[+]

Wheat grass exact induces apoptosis in human cancer cells via proteasome modulation.


Natural occurring modulators of proteasome functionality are extensively investigated for their implication in cancer therapy. On the basis of our previous evidences both on proteasomal inhibition by monomeric polyphenols, and on the characterization of wheat sprout hydroalcoholic extract, herein we thoroughly report on a comparative study of the effect of wheat sprout extract on both normal and tumour cells. Treatment of isolated 20S proteasomes with wheat sprout extracts induced a gradual inhibition of all proteasome activities. Next, two wheat sprout extract components were separated: a polyphenol and a protein fraction. Both components exerted an in vitro inhibitory effect on proteasome activity. HeLa tumour cells and FHs 74 Int normal cells were exposed to both fractions, resulting in different rates of proteasome inhibition, with tumour cells showing a significantly higher degree of proteasome impairment and apoptosis induction. Furthermore, a decrease in proteasome activities and in cell survival of the human plasmacytoma RPMI 8226 cell line, upon the same treatments, was observed. Collectively, our results provide additional evidences supporting the possible use of natural extracts as coadjuvants in cancer treatments.

Pharmacopsychiatry. 1997 Jul;30(4):133-4. PMID: 19527768

275
[+]

Addition of whole, semiskimmed, and skimmed bovine milk reduces the total antioxidant capacity of black tea.


Epidemiological studies have shown that populations consuming fruits, vegetables, tea, cocoa, and red wine have lower incidences of cardiovascular disease, certain cancers, and eye disease. These health effects have largely been attributed to the polyphenol content of the foods and drinks studied. Black tea is rich in a range of polyphenolic compounds that could potentially have health-promoting properties. The scale of consumption of tea in the United Kingdom means that it could be an appropriate vehicle for increasing the antioxidant activity and polyphenol content of human plasma. However, it is common practice in the United Kingdom to add milk to tea, and some studies have suggested that this may decrease the overall antioxidant capacity. The objective of the present study was to analyze and compare the antioxidant capacity of 5 brands of tea and to test the hypothesis that the addition of different volumes of whole milk, semiskimmed, and skimmed milk may affect the antioxidant capacity. Each of the teas analyzed was a significant source of antioxidants. The addition of 10, 15, and 20 mL of whole, semiskimmed, and skimmed bovine milk to a 200-mL tea infusion decreased the total antioxidant capacity of all the brands of tea. Skimmed milk decreased the total antioxidant capacity of the tea infusion significantly (P

Nutr Res. 2010 Jan;30(1):14-20. PMID: 20116655

276
[+]

Cocoa extract reduces benzo[a]pyrene-induced mutagenicity.


Polyphenols have been shown to have potent antioxidant activity, and therefore, food containing polyphenols is expected to contribute to the prevention of cancer. However, food contains not only polyphenols but also various other constituents. We used the Ames test to investigate the effects of crude extracts of whole cacao products, which are known to be rich in polyphenols, on the mutagenicity of benzo[a]pyrene (B[a]P) in Salmonella typhimurium strain TA 98 and tert-butyl hydroperoxide (t-BuOOH) in S. typhimurium strain TA 102. B[a]P induces mutagenicity by metabolic activation and t-BuOOH induces it by generation of free radicals. While white chocolate did not modulate the numbers of revertant colonies produced by B[a]P treatment, milk chocolate and cacao powder extracts did. On the other hand, surprisingly, none of the cacao products tested affected the number of revertant colonies when t-BuOOH was used as the mutagen. At maximum concentration (13.25 mg cacao powder/ml), the crude cacao powder extract reduced ethoxyresorufin O-deethylase activity to 17.4% of the control, suggesting that whole cacao products inhibit cytochrome P450 (CYP) 1A activity. In conclusion, inhibition of CYP1A activity by cacao products may prevent DNA damage by reducing metabolic activation of carcinogens.

Phytother Res. 2009 Aug;23(8):1134-9. PMID: 19170136

277
[+]

Cocoa polyphenols extracts have an antiproliferative effect on prostate cancer cell growth.


Cocoa contains many different types of physiologically active components. It was shown that cocoa beans are rich in specific antioxidants such as flavonoids, catechins, epicatechins and proanthocyanidins. Additionally, beta-sitosterol, the most common phytosterol, may play a protective role in the development of cancer. The aim of this in-vitro study was to evaluate the inhibitory effect of different cocoa polyphenols extracts, alone or combined with beta-sitosterol, on two human prostate cancer cell lines (nonmetastatic 22Rv1 cells and metastatic DU145 cells) and a normal human prostate cell line (RWEP-1). A synergy between beta-sitosterol and cocoa polyphenols extract was also researched. Cells were treated independently with five products from 1 to 72 h: (1/) synthetic beta-sitosterol, (2/) a cocoa polyphenols extract supplemented with beta-sitosterol, (3/) three different cocoa polyphenols extracts naturally containing beta-sitosterol. In the experiment, beta-sitosterol was tested from 10(-6) to 10(-3)%; cocoa polyphenols extract supplementation was with 0.72% beta-sitosterol; finally cocoa polyphenols extracts were added to the cells at very low concentrations ranging from 0.001 to 0.2%. The growth and viability of cells were measured using colorimetric assay at 1, 3, 6, 24, 48 and 72 h of treatment. IC50 and IC100 corresponding to the concentration leading to a decrease of 50% and 100% of cell growth were determined. At the highest tested concentration, cocoa polyphenols extracts induced a complete inhibition of growth of metastatic and nonmetastatic cancer cell lines. In addition, cocoa polyphenols extracts were more active against local cancer cells than against metastatic cells. Moreover, at the highest tested concentration, cocoa polyphenols extracts are not effective on a normal prostate cell lines. Beta-sitosterol induced low growth inhibition of both cancer cell line. Cocoa polyphenols extracts, however, were significantly more active and showed a strong and fast inhibition of cell growth than beta-sitosterol alone. No synergy or addition was observed when beta-sitosterol was tested together with the cocoa polyphenols extract. Our results show that cocoa polyphenols extracts have an antiproliferative effect on prostate cancer cell growth but not on normal cells, at the highest tested concentration.

Am J Physiol Renal Physiol. 2007 Oct;293(4):F1256-61. Epub 2007 Aug 1. PMID: 16835506

278
[+]

An anthocyanin fraction from potato extracts is cytotoxic to prostate cancer cells.


Polyphenols from fruits and vegetables exhibit anticancer properties both in vitro and in vivo and specialty potatoes are an excellent source of dietary polyphenols, including phenolic acids and anthocyanins. This study investigated the effects of specialty potato phenolics and their fractions on LNCaP (androgen dependent) and PC-3 (androgen independent) prostate cancer cells. Phenolic extracts from four specialty potato cultivars CO112F2-2, PATX99P32-2, ATTX98462-3 and ATTX98491-3 and organic acid, phenolic acid and anthocyanin fractions (AF) were used in this study. CO112F2-2 cultivar extracts and their AF at 5 mug chlorogenic acid eq/ml were more active and inhibited cell proliferation and increased the cyclin-dependent kinase inhibitor p27 levels in both LNCaP and PC-3 cells. Potato extract and AF induced apoptosis in both the cells and, however, the effects were cell context dependent. Cell death pathways induced by potato extract and AF were associated with mitogen-activated protein kinase and c-jun N-terminal kinase activation and these kinases activated caspase-independent apoptosis through nuclear translocation of endonuclease G (Endo G) and apoptosis-inducing factor in both cell lines. Induction of caspase-dependent apoptosis was also kinase dependent but was observed only in LNCaP cells. Kinase inhibitors reversed this nuclear translocation of endonuclease G and apoptosis-inducing factor. This is the first report showing that the cytotoxic activities of potato extract/AF in cancer cells were due to activation of caspase-independent apoptosis. Current studies are focused on identifying individual components of the AF responsible for the induction of cell death pathways in prostate and other cancer cell lines and developing potato cultivars that overexpress these active compounds.

Carcinogenesis. 2007 Oct;28(10):2227-35. Epub 2007 May 23. PMID: 17522067

279
[+]

Curcumin has anti-breast cancer activity.


Since curcumin, a polyphenol extracted from the rhizomes of Curcuma longa L. (Zingiberaceae), has been proposed for breast cancer chemoprevention, the aim of the present work was to determine if it had anti-tumour effects on mammary cells which are resistant to oxidative damage. ZR-75-1 cells were treated with curcumin and copper(II) sulphate in order to evaluate cell death and gamma-glutamyltranspeptidase (GGTP) activity. Curcumin was cytotoxic in a dose-dependent manner (loss of viability with lactate-dehydrogenase release) with apoptotic effects on ZR-75-1 cells. Also, curcumin displayed an antioxidant effect only on the copper-oxidized cells. The GGTP activity was decreased in a dose-dependent manner by curcumin, with the changes in this parameter accounting for neoplastic inhibition (direct relation between the enzyme activity and cellular viability). Summing up, our results suggest that curcumin induced apoptosis in ZR-75-1 with an antioxidant activity performed on those treated with copper(II) sulphate, which should be explored more thoroughly with the involvement of the GGTP enzyme activity as biomarker of their malignancy.

J Exp Ther Oncol. 2010;8(3):261-6. PMID: 20734924

280
[+]

Coffee may exert its chemopreventive properties through metabolism and detoxification of xenobiotics.


Enzymes of xenobiotic metabolism are involved in the activation and detoxification of carcinogens and can play a pivotal role in the susceptibility of individuals toward chemically induced cancer. Differences in such susceptibility are often related to genetically predetermined enzyme polymorphisms but may also be caused by enzyme induction or inhibition through environmental factors or in the frame of chemopreventive intervention. In this context, coffee consumption, as an important lifestyle factor, has been under thorough investigation. Whereas the data on a potential procarcinogenic effect in some organs remained inconclusive, epidemiology has clearly revealed coffee drinkers to be at a lower risk of developing cancers of the colon and the liver and possibly of several other organs. The underlying mechanisms of such chemoprotection, modifications of xenobiotic metabolism in particular, were further investigated in rodent and in vitro models, as a result of which several individual chemoprotectants out of the>1000 constituents of coffee were identified as well as some strongly metabolized individual carcinogens against which they specifically protected. This chapter discusses the chemoprotective effects of several coffee components and whole coffee in association with modifications of the usually protective glutathione-S-transferase (GST) and the more ambivalent N-acetyltransferase (NAT). A key role is played by kahweol and cafestol (K/C), two diterpenic constituents of the unfiltered beverage that were found to reduce mutagenesis/tumorigenesis by strongly metabolized compounds, such as 2-amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine, 7,12-dimethylbenz[a]anthracene, and aflatoxin B(1), and to cause various modifications of xenobiotic metabolism that were overwhelmingly beneficial, including induction of GST and inhibition of NAT. Other coffee components such as polyphenols and K/C-free coffee are also capable of increasing GST and partially of inhibiting NAT, although to a somewhat lesser extent.

Methods Enzymol. 2005;401:307-41. PMID: 16399395

281
[+]

Oats contain more than 20 unique polyphenols with strong antioxidant activity.


Oats are known to be a healthy food for the heart due mainly to their high beta-glucan content. In addition, they contain more than 20 unique polyphenols, avenanthramides, which have shown strong antioxidant activity in vitro and in vivo. The polyphenols of oats have also recently been shown to exhibit anti-inflammatory, antiproliferative, and anti-itching activity, which may provide additional protection against coronary heart disease, colon cancer, and skin irritation.

Nutr Rev. 2009 Dec;67(12):731-5. PMID: 19941618

282
[+]

buckwheat extract has antioxidant and photoprotective properties.


In recent years, the incidence of skin cancer has risen remarkably. Sun light, especially the included ultraviolet (UV)-radiation, is seen as important trigger for the development of skin cancer. Thus, there is an increasing interest in the development of UV-protective substances to use them as sun care products. One approach is the topical application of herbal antioxidants. Plant-derived antioxidants are often extracts and therefore contain a complex mixture of constituents, like flavonoids and polyphenols, which contribute to the overall activity of the extract. In the present study an extract from buckwheat herb was compared to rutin, which is the main constituent of the extract, regarding their antioxidant and radical scavenging activity. Additionally, the photoprotective properties of the extract were compared to those of a commercial UV absorber. The antioxidant activity was quantified regarding the reactivity versus the 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH). The photoprotective properties of the extract were examined by the inhibition of the photosensitized lipid peroxidation of linolic acid. In the DPPH assay, the extract had significantly better antioxidant activity than pure rutin. The extract prevented more effectively the UV-induced peroxidation of linolic acid than rutin itself or the commercial UV absorber. The use of the extract from buckwheat herb seems to be more beneficial than the use of pure rutin. This can be referred to the presence of minor phenolic compounds in the extract. The results indicate that it is advisable to use antioxidants rather than only UV absorber to obtain a maximum of photo protection.

Pharmazie. 2006 Mar;61(3):237-40. PMID: 16599267

283
[+]

Polyphenols may reduce chemotherapy resistance in cancer cells.


TNF-related apoptosis-inducing ligand (TRAIL) and its receptors are attractive targets for anticancer therapy owing to their ability to trigger apoptosis selectively in cancer cells but not in normal cells. To date, many combinatorial strategies, such as chemotherapy or radiotherapy, have given encouraging results for overcoming TRAIL resistance in preclinical models. In this review, we provide an overview of the molecular mechanisms underlying sensitization to TRAIL-induced apoptosis by polyphenols. These naturally occurring compounds can restore tumor cell sensitivity to TRAIL-induced cell death with no apparent toxicity towards normal cells. Both extrinsic and intrinsic pathways can be modulated by polyphenols, the activation of which largely depends on the cell type, the particular polyphenolic compound, and the conditions of treatment. The large variety of polyphenol cellular targets could prove useful in circumventing TRAIL resistance. The relevance of these combined treatments for cancer therapy is discussed in the light of recent preclinical studies.

Cell Mol Life Sci. 2010 Sep;67(18):3115-30. Epub 2010 May 29. PMID: 20508968

284
[+]

Review: Resveratrol's therapeutic role in Alzheimer's disease.


Resveratrol, a red wine polyphenol, is known to protect against cardiovascular diseases and cancers, as well as to promote antiaging effects in numerous organisms. It also modulates pathomechanisms of debilitating neurological disorders, such as strokes, ischemia, and Huntington's disease. The role of resveratrol in Alzheimer's disease is still unclear, although some recent studies on red wine bioactive compounds suggest that resveratrol modulates multiple mechanisms of Alzheimer's disease pathology. Emerging literature indicates that mechanisms of aging and Alzheimer's disease are intricately linked and that these mechanisms can be modulated by both calorie restriction regimens and calorie restriction mimetics, the prime mediator of which is the SIRT1 protein, a human homologue of yeast silent information regulator (Sir)-2, and a member of NAD+-dependent histone deacetylases. Calorie restriction regimens and calorie restriction-mimetics trigger sirtuins in a wide variety of organisms, ranging from bacteria to mouse. In a mouse model of Huntington's disease, resveratrol-induced SIRT1 was found to protect neurons against ployQ toxicity and in Wallerian degeneration slow mice, resveratrol was found to protect the degeneration of neurons from axotomy, suggesting that resveratrol may possess therapeutic value to neuronal degeneration. This paper mainly focuses on the role of resveratrol in modulating AD pathomechanisms.

Brain Res Rev. 2006 Sep;52(2):316-26. PMID: 16766037

285
[+]

Rosmarinic acid encourages cell death in human leukemia cells.


Because tumor necrosis factor-alpha (TNF-alpha) is well-known to induce inflammatory responses, thus its clinical use is limited in cancer treatment. Rosmarinic acid (RA), a naturally occurring polyphenol flavonoid, has been reported to inhibit TNF-alpha-induced NF-kappaB activation in human dermal fibroblasts. However, the precise mechanisms of RA have not been well elucidated in TNF-alpha-mediated anti-cancer therapy. In this study, we found that RA treatment significantly sensitizes TNF-alpha-induced apoptosis in human leukemia U937 cells through the suppression of nuclear transcription factor-kappaB (NF-kappaB) and reactive oxygen species (ROS). Activation of caspases in response to TNF-alpha was markedly increased by RA treatment. However, pretreatment with the caspase-3 inhibitor, z-DEVD-fmk, was capable of significantly restoring cell viability in response to combined treatment. RA also suppressed NF-kappaB activation through inhibition of phosphorylation and degradation of IkappaBalpha, and nuclear translocation of p50 and p65. This inhibition was correlated with suppression of NF-kappaB-dependent anti-apoptotic proteins (IAP-1, IAP-2, and XIAP). RA treatment also normalized TNF-alpha-induced ROS generation. Additionally, ectopic Bcl-2 expressing U937 reversed combined treatment-induced cell death, cytochrome c release into cytosol, and collapse of mitochondrial potential. These results demonstrated that RA inhibits TNF-alpha-induced ROS generation and NF-kappaB activation, and enhances TNF-alpha-induced apoptosis.

Cancer Lett. 2010 Feb 28;288(2):183-91. Epub 2009 Jul 19. PMID: 19619938

286
[+]

Immature plum induces programmed cell death in liver cancer cells.


In the present study, the effect of an extract of immature Prunus salicina Lindl. cv. Soldam fruit on the viability and induction of apoptosis in human hepatocellular carcinoma HepG2 cells was investigated. The results showed that in comparison with other cancer cells, the growth inhibition exerted by immature plum extracts was greatest in HepG2. Apoptosis in HepG2 cells mediated by immature plums was associated with "death receptor signaling." Immature plum extracts significantly increased the activation of caspase-8, -10, and -3 and expression of the caspase-3 target proteins alpha-fodrin (induces membrane blebbing and cell shrinkage), poly(ADP-ribose) polymerase (a nuclear enzyme that is involved in DNA repair following DNA nicks), and DNA fragmentation factor (induces apoptotic DNA fragmentation). The total yield of identified polyphenols in immature plum extract was 10 g/kg dry weight. The major components, (-)-epicatechin and (-)-gallocatechin gallate, were 34.7% and 28.6% of total polyphenols, respectively. (+)-Catechin, (-)-epicatechin gallate, and (-)-catechin gallate were also found. On the basis of these results, the immature plum (P. salicina Lindl. cv. Soldam) and its active compound, (-)-epicatechin, are expected to be a natural resource for developing novel therapeutic agents for cancer prevention and treatment.

J Med Food. 2009 Jun;12(3):518-27. PMID: 19627199

287
[+]

Flavanoid rich honey may act as chemosensitizers in multidrug resistant cancers.


Cancer is one of the deadly diseases that burdens the society since long-time. Although design of chemotherapy is well-advanced, still it could not prevent the cancer death by hundred percent. One of the major stumbling blocks for cancer chemotherapy is multidrug resistance (MDR) developed by cancer cells. Role of ABC family of transporter proteins is well recognized in MDR. P-glycoprotein (P-gp), member of ABC transporter family, has been described for drug resistance and a low bioavailability of drugs by pumping structurally unrelated drugs out of the cells at the cost of ATP hydrolysis. Recently various P-gp inhibitors (chemosensitizers) are studied extensively to reverse MDR. In this scenario, we propose honey with multitude of polyphenolic flavonoids as a plausible candidate for inhibiting the P-gp proteins. Common flavonoids of honey like chrysin, genistein, biochanin, quercetin, kaempferol, and naringenin have found to interact with P-gp transporters. Generally chemosensitizers bind with transmembrane domain (TMD) in the P-gp transporter but flavonoids are bi-functional in reversing the MDR. Flavonoids can inhibit the ATPases activity involved in drug efflux and also it may serve as substrates for P-gp transporters, thereby causing competitive inhibition towards other substrates. This dual-mode of flavonoids interaction with P-gp transporter enhances the therapeutic index. Hence we promulgate honey with rich flavonoid content as a potential candidate for reversing MDR. If our hypothesis is true, honey a novel chemosensitizer will reduce the huge amount invested in developing new chemosensitizers to overcome the burden of chemo-resistance.

Med Hypotheses. 2011 Jan 17. Epub 2011 Jan 17. PMID: 21247706

288
[+]

Red wine polyphenols cause growth inhibition and programmed cell death in acute lymphoblastic leukaemia cells.


Several epidemiological studies suggest that a diet rich in fruits and vegetables, which contain high levels of polyphenols, is associated with a reduced risk of cancer. The aim of the present study was to determine whether a red wine polyphenolic extract (RWPs, a rich source of polyphenols; 2.9g/L) affects the proliferation of human lymphoblastic leukaemia cells (Jurkat cells) and, if so, to determine the underlying mechanism. Cell proliferation and viability were determined by the MTS and trypan blue exclusion assays, respectively. Cell cycle analysis, apoptosis activity and oxidative stress levels were assessed by flow cytometry, and the expression of p73, UHRF1 and active caspase-3 by Western blot analysis. RWPs inhibited the proliferation of Jurkat cells and induced G0/G1 cell cycle arrest in a concentration-dependent manner. Moreover, RWPs triggered apoptosis, which is associated with an increased expression level of the pro-apoptotic protein p73 and the active caspase-3. RWPs induced apoptosis confirmed by DNA fragmentation analysis, and this effect was associated with down-regulation of the antiapoptotic protein UHRF1. Furthermore RWPs significantly increased the formation of reactive oxygen species (ROS). Intracellular scavengers of superoxide anions (MnTMPyP, MnTBAP, PEG-SOD) prevented the RWPs-induced formation of ROS and apoptosis, while native extracellular superoxide dismutase (SOD) was without effect. In addition, the effect of RWPs on the expression levels of p73, active caspase-3 and UHRF1 was also prevented by MnTMPyP. Thus, these findings indicate that RWPs induce apoptosis in Jurkat cells by a redox-sensitive mechanism involving the intracellular formation of superoxide anions and consequently the up-regulation of p73 and down-regulation of UHRF1.

Eur J Cancer. 2010 Mar;46(5):983-94. Epub 2010 Jan 13. PMID: 20074931

289
[+]

Brazillian enhances programmed cell death in prostate cancer cells.


Prostate cancer represents an ideal disease for chemopreventive intervention. Propolis possesses immuno-modulatory, anti-tumour and chemopreventive properties. The tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) is an important endogenous anti-cancer agent that induces apoptosis selectively in tumour cells. However, some cancer cells are resistant to TRAIL-mediated apoptosis. Naturally occurring phenolic and polyphenolic compounds sensitize TRAIL-resistant cancer cells and augment the apoptotic activity of TRAIL. The ethanolic extract of Brazilian green propolis (EEP) is rich in phenolic components. Our in vitro results indicate the potential targets in the TRAIL-induced apoptotic pathway for the cancer chemopreventive activity of Brazilian propolis. We examined the cytotoxic and apoptotic effects of Brazilian EEP and its bioactive components in combination with TRAIL on LNCaP prostate cancer cells.The chemical composition of Brazilian green propolis was determined by high performance liquid chromatography-diode array detection. The cytotoxicity was measured by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl-tetrazolium and lactate dehydrogenase assays. Apoptosis was detected using annexin V-FITC by flow cytometry and fluorescence microscopy. The mitochondrial membrane potential (∆Ψm) was evaluated using DePsipher staining by fluorescence microscopy. Flow cytometry was used to analyse death receptor (TRAIL-R1 and TRAIL-R2) expression in LNCaP cells. The inhibition of nuclear factor-κB (NF-κB) (p65) activation in cancer cells was confirmed by the ELISA-based TransAM NF-κB kit. The LNCaP cells were shown to be resistant to TRAIL-induced apoptosis. Our study demonstrates that EEP sensitizes TRAIL-resistant prostate cancer cells. The main phenolic components detected in Brazilian green propolis are artepillin C, quercetin, kaempferol and p-coumaric acid. Brazilian propolis and its bioactive components markedly augmented TRAIL-mediated apoptosis and cytotoxicity in prostate cancer cells. Brazilian EEP enhanced the expression of TRAIL-R2 and the activity of NF-κB in LNCaP cells.The co-treatment of prostate cancer cells with 100 ng/ml TRAIL and 50 µg/ml EEP increased the percentage of apoptotic cells to 65.8±1.2% and caused a significant disruption of ∆Ψm in LNCaP cells. We show that Brazilian EEP helped cells overcome TRAIL resistance by engaging both intrinsic andextrinsic apoptotic pathways and regulating NF-κB activity. The data demonstrate the important role of Brazilian green propolis and its bioactive compounds in prostate cancer chemoprevention through the enhancement of TRAIL-mediated apoptosis.

Int J Oncol. 2011 Feb 1. Epub 2011 Feb 1. PMID: 21286663

290
[+]

Review: Curcumin has therapeutic potential in the treatment of head & neck cancers.


ABSTRACT: Curcumin (diferuloylmethane) is a polyphenol derived from the Curcuma longa plant, commonly known as turmeric. Curcumin has been used extensively in Ayurvedic medicine for centuries, as it is nontoxic and has a variety of therapeutic properties including anti-oxidant, analgesic, anti-inflammatory and antiseptic activity. More recently curcumin has been found to possess anti-cancer activities via its effect on a variety of biological pathways involved in mutagenesis, oncogene expression, cell cycle regulation, apoptosis, tumorigenesis and metastasis. Curcumin has shown anti-proliferative effect in multiple cancers, and is an inhibitor of the transcription factor NF-kB and downstream gene products (including c-myc, Bcl-2, COX-2, NOS, Cyclin D1, TNF-alpha, interleukins and MMP-9). In addition, curcumin affects a variety of growth factor receptors and cell adhesion molecules involved in tumor growth, angiogenesis and metastasis. Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide and treatment protocols include disfiguring surgery, platinum-based chemotherapy and radiation, all of which may result in tremendous patient morbidity. As a result, there is significant interest in developing adjuvant chemotherapies to augment currently available treatment protocols, which may allow decreased side effects and toxicity without compromising therapeutic efficacy. Curcumin is one such potential candidate, and this review presents an overview of the current in vitro and in vivo data supporting its therapeutic activity in head and neck cancer as well as some of the challenges concerning its development as an adjuvant chemotherapeutic agent.

Mol Cancer. 2011 Feb 7;10(1):12. Epub 2011 Feb 7. PMID: 21299897

291
[+]

Testoterone enhances curcumin's anti-prostate cancer activity.


Recently, we reported that combined ingestion of soy isoflavones and curcumin significantly decreased the serum level of prostate-specific antigen based on a randomized placebo-controlled double-blind clinical study. We investigated whether these polyphenols inhibited the proliferation of prostate cancer cells by activating a DNA damage response. The effects of isoflavones and curcumin on the expression and phosphorylation of ataxia-telangiectasia-mutated kinase (ATM), histone H2AX variant (H2AX) and checkpoint kinase2 (Chk2) were examined in LNCaP cells. The induction of apoptosis in LNCaP cells was evaluated by poly(ADP-ribose) polymerase (PARP) cleavage. Furthermore, the effects of a testosterone supplement on modulation of the DNA damage response were examined. Combined treatment of isoflavones and curcumin additively suppressed cellular proliferation and induced phosphorylation of ATM, histone H2AX, Chk2 and p53. Testosterone augmented the activation of the DNA damage response and PARP cleavage induced by curcumin. Our results indicate that activation of the DNA damage response by polyphenols might suppress the malignant transformation of prostate cancer. In addition, testosterone, when combined with curcumin, may have suppressive effects on the progression of prostate cancer. (Cancer Sci 2011; 102: 468-471).

Cancer Sci. 2011 Feb;102(2):468-71. Epub 2010 Dec 7. PMID: 21134073

292
[+]

Curcumin compares favorably with oxaliplatin as an antiproliferative in colorectal cell lines.


Colorectal cancer remains a leading cause of cancer death worldwide, despite markedly improved response rates to current systemic therapies. Oxaliplatin either alone or incorporated into 5-fluorouracil/leucovorin regimes has resulted in increased survival rates, particularly with regards to metastatic colorectal carcinoma. The chemopreventive polyphenol curcumin, which is currently in clinical trial, has been advocated for use in colorectal cancer either singly or in combination with chemotherapeutic drugs. In this study, the antiproliferative capacity of both compounds was compared in HCEC (normal-derived), HT29 (p53 mutant adenocarcinoma) and HCT116 (p53wt adenocarcinoma) colorectal cell lines to determine whether effects were cell-type specific at pharmacologically achievable doses, and whether the combination resulted in enhanced efficacy. Both oxaliplatin and curcumin displayed marked antiproliferative capacity at therapeutic concentrations in the two tumor cell lines. Order of sensitivity to oxaliplatin was HCT116>HT29>HCEC, whereas order of sensitivity to curcumin was HT29>HCT116>HCEC. HCT116 cells underwent induction of G2/M arrest in response to both oxaliplatin (irreversible) and curcumin (reversible). Apoptosis was induced by both agents, and up to 16-fold induction of p53 protein was observed in response to the combination. Antiproliferative effects in HT29 cells were largely cell cycle independent, and were mediated by induction of apoptosis. Effects were greatly enhanced in both cell lines when agents were combined. This study provides further evidence that curcumin may be of use in therapeutic regimes directed against colorectal cancer, and suggests that in combination with oxaliplatin it may enhance efficacy of the latter in both p53wt and p53 mutant colorectal tumors.

Int J Cancer. 2007 Jul 1;121(1):175-83. PMID: 17330230

293
[+]

Curcumin inhibits cholesterol uptake.


BACKGROUND: Curcumin is a polyphenol and the one of the principle curcuminoids of the spice turmeric. Its antioxidant, anti-cancer and anti-inflammatory effects have been intensively studied. Previous in vivo studies showed that administration of curcumin also decreased cholesterol levels in the blood, and the effects were considered to be related to upregulation of LDL receptor. However, since plasma cholesterol levels are also influenced by the uptake of cholesterol in the gut, which is mediated by a specific transporter Niemann-Pick Cl-like 1 (NPC1L1) protein, the present study is to investigate whether curcumin affects cholesterol uptake in the intestinal Caco-2 cells.METHODS: Caco-2 cells were cultured to confluence. The micelles composed of bile salt, monoolein, and 14C-cholesterol were prepared. We first incubated the cells with the micelles in the presence and absence of ezetimibe, the specific inhibitor of NPC1L1, to see whether the uptake of the cholesterol in the cells was mediated by NPC1L1. We then pretreated the cells with curcumin at different concentrations for 24 h followed by examination of the changes of cholesterol uptake in these curcumin-treated cells. Finally we determined whether curcumin affects the expression of NPC1L1 by both Western blot analysis and qPCR quantification.RESULTS: We found that the uptake of radioactive cholesterol in Caco-2 cells was inhibited by ezetimibe in a dose-dependent manner. The results indicate that the uptake of cholesterol in this study was mediated by NPC1L1. We then pretreated the cells with 25-100 muM curcumin for 24 h and found that such a treatment dose-dependently inhibited cholesterol uptake with 40% inhibition obtained by 100 muM curcumin. In addition, we found that the curcumin-induced inhibition of cholesterol uptake was associated with significant decrease in the levels of NPC1L1 protein and NPC1L1 mRNA, as analyzed by Western blot and qPCR, respectively.CONCLUSION: Curcumin inhibits cholesterol uptake through suppression of NPC1L1 expression in the intestinal cells.

Lipids Health Dis. 2010;9:40. Epub 2010 Apr 19. PMID: 20403165

294
[+]

Curcumin may facilitate chemoprevention via direct binding to, and activation of, vitamin D receptor (VDR).


The nuclear vitamin D receptor (VDR) mediates the actions of 1,25-dihydroxyvitamin D(3) (1,25D) to regulate gene transcription. Recently, the secondary bile acid, lithocholate (LCA), was recognized as a novel VDR ligand. Using reporter gene and mammalian two-hybrid systems, immunoblotting, competitive ligand displacement and quantitative real-time PCR, we identified curcumin (CM), a turmeric-derived bioactive polyphenol, as a likely additional novel ligand for VDR. CM (10(-5) M) activated transcription of a luciferase plasmid containing the distal vitamin D responsive element (VDRE) from the human CYP3A4 gene at levels comparable to 1,25D (10(-8) M) in transfected human colon cancer cells (Caco-2). While CM also activated transcription via a retinoid X receptor (RXR) responsive element, activation of the glucocorticoid receptor (GR) by CM was negligible. Competition binding assays with radiolabeled 1,25D confirmed that CM binds directly to VDR. In mammalian two-hybrid assays employing transfected Caco-2 cells, CM (10(-5) M) increased the ability of VDR to recruit its heterodimeric partner, RXR, and steroid receptor coactivator-1 (SRC-1). Real-time PCR studies revealed that CM-bound VDR can activate VDR target genes CYP3A4, CYP24, p21 and TRPV6 in Caco-2 cells. Numerous studies have shown chemoprotection by CM against intestinal cancers via a variety of mechanisms. Small intestine and colon are important VDR-expressing tissues where 1,25D has known anticancer properties that may, in part, be elicited by activation of CYP-mediated xenobiotic detoxification and/or up-regulation of the tumor suppressor p21. Our results suggest the novel hypothesis that nutritionally-derived CM facilitates chemoprevention via direct binding to, and activation of, VDR.

J Nutr Biochem. 2010 Dec;21(12):1153-61. Epub 2010 Feb 12. PMID: 20153625

295
[+]

Curcumin may work synergistically with taxane chemotherapy for hormone-refractory prostate cancer treatment.


Complementary and alternative therapies for neoplastic diseases treatment and prevention receive increasing attention from the medical community. Prostate cancer (PC) is the most frequently diagnosed malignancy and the second major cause of male death in industrialized countries. The chemopreventive properties and clinical safety of curcumin, a polyphenolic derivative, have already been established. However, curcumin regimen value in addition to conventional hormone refractory (HR) PC treatment remains largely unknown. This review article summarizes mechanisms by which curcumin may decrease HRPC aggressive proliferation and potentiate activity of taxane therapy. Our analysis suggests that curcumin alone has a therapeutic value in HRPC. In combination with a taxane agent, this compound may enhance cytotoxicity and retard PC cell resistance to taxane. As a consequence, a rationale is provided for considering the possible benefits of curcumin regimen in combination with taxane therapy in HRPC patients.

Nutr Cancer. 2010;62(2):148-53. PMID: 20099188

296
[+]

Curcumin inhibits IMP dehydrogenase, a target for anticancer and antiviral chemotherapy agents.


Inosine monophosphate dehydrogenase (IMPDH), a rate-limiting enzyme in the de novo synthesis of guanine nucleotides, is a therapeutic target for anticancer and antiviral agents. Among the 15 different polyphenols examined, curcumin was found to have an inhibitory effect on the IMPDH activity in both a competitive and uncompetitive manner and to suppress the cellular GTP level in HT-29 colon carcinoma cells.

Biosci Biotechnol Biochem. 2010;74(1):185-7. Epub 2010 Jan 7. PMID: 20057137

297
[+]

Curcumin inhibits Ewing sarcoma.


Curcumin is a naturally occurring polyphenolic compound found in the turmeric, which is used as food additive in Indian cooking and as a therapeutic agent in traditional Indian medicine. Curcumin is currently under investigation as a chemotherapeutic and chemopreventive agent in adult cancer models at both pre-clinical and clinical levels. In this preliminary study, we show that curcumin is effective in causing cell cycle arrest, inducing apoptosis, and suppressing colony formation in the Ewing sarcoma cell line SK-NEP-1. Curcumin causes upregulation of cleaved caspase 3 and downregulation of phospho-Akt, producing apoptosis in Ewing sarcoma cells at an inhibitory concentration 50% (IC50) of approximately 4 μM. Our findings indicate a need for further evaluation of curcumin in chemotherapy and chemoprevention of Ewing sarcoma.

Med Oncol. 2010 Dec;27(4):1096-101. Epub 2009 Oct 27. PMID: 19859844

298
[+]

Curcumin inhibit human lung cancer cells.


Curcumin, a polyphenolic compound, is the active component of Curcuma longa and has been extensively investigated as an anticancer drug that modulates multiple pathways. Eukaryotic initiation factors (eIFs) have been known to play important roles in translation initiation, which controls cell growth and proliferation. Little is known about the effects of curcumin on eIFs in lung cancer. The objective of this study was to exam the curcumin cytotoxic effect and modulation of two major rate-limiting translation initiation factors, including eIF2α and eIF4E protein expression levels in lung adenocarcinoma epithelial cell line A549. Cytotoxicity was measured by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and protein changes were determined by Western blot. A549 cells were treated with 0-240 μM curcumin for 4-96h. The inhibitory effects of curcumin on cytotoxicity were dose- and time-dependent (P

Mol Biol Rep. 2010 Oct;37(7):3105-10. Epub 2009 Oct 15. PMID: 19826913

299
[+]

Review: Curcumin may be an ideal anti-cancer therapy due to is role in positively modulating the machineries of cell survival, proliferation, invasion, and angiogenesis.


Although safe in most cases, ancient treatments are ignored because neither their active components nor their molecular targets are well defined. This is not the case, however, with curcumin, a yellow-pigment substance and component of turmeric (Curcuma longa), which was identified more than a century ago. Recently, extensive research has addressed the chemotherapeutic potential of this relatively nontoxic-plant-derived polyphenol. Because most cancers are caused by deregulation of as many as 500 different genes, agents that target multiple gene products are needed for prevention and treatment of cancer. In this regard, curcumin has been reported to have immense potentiality for being used in cancer chemotherapy because of its control over the machineries of cell survival, proliferation, invasion, and angiogenesis. The mechanisms implicated are diverse and appear to involve a combination of cell signaling pathways at multiple levels. This review seeks to summarize the unique multifocal signal modulatory properties of the "ancient weapon," curcumin, which may be exploited for successful clinical cancer prevention.

Mol Cell Biochem. 2010 Mar;336(1-2):85-95. Epub 2009 Oct 14. PMID: 19826768

300
[+]

Curcumin may block brain tumor formation.


Turmeric, an essential ingredient of culinary preparations of southeast Asia, contains a major polyphenolic compound, named curcumin or diferuloylmethane, which eliminates cancer cells derived from a variety of peripheral tissues. Although in vitro experiments have addressed its anti-tumor property, no in vivo studies have explored its anti-cancer activity in the brain. Oral delivery of this food component has been less effective because of its low solubility in water. We show that a soluble formulation of curcumin crosses the blood-brain barrier but does not suppress normal brain cell viability. Furthermore, tail vein injection, or more effectively, intracerebral injection through a cannula, blocks brain tumor formation in mice that had already received an intracerebral bolus of mouse melanoma cells (B16F10). While exploring the mechanism of its action in vitro we observed that the solubilized curcumin causes activation of proapoptotic enzymes caspase 3/7 in human oligodendroglioma (HOG) and lung carcinoma (A549) cells, and mouse tumor cells N18 (neuroblastoma), GL261 (glioma), and B16F10. A simultaneous decrease in cell viability is also revealed by MTT [3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide] assays. Further examination of the B16F10 cells showed that curcumin effectively suppresses Cyclin D1, P-NF-kB, Bcl(XL), P-Akt, and VEGF, which explains its efficacy in blocking proliferation, survival, and invasion of the B16F10 cells in the brain. Taken together, solubilized curcumin effectively blocks brain tumor formation and also eliminates brain tumor cells. Therefore, judicious application of such injectable formulations of curcumin could be developed into a safe therapeutic strategy for treating brain tumors.

Brain Res. 2009 Feb 10. Epub 2009 Feb 10. PMID: 19368804

This website is for information purposes only. By providing the information contained herein we are not diagnosing, treating, curing, mitigating, or preventing any type of disease or medical condition. Before beginning any type of natural, integrative or conventional treatment regimen, it is advisable to seek the advice of a licensed healthcare professional.

© Copyright 2008-2019 GreenMedInfo.com, Journal Articles copyright of original owners, MeSH copyright NLM.