β-elemene reverses chemoresistance of breast cancer via regulating MDR-related microRNA expression.
Cell Physiol Biochem. 2014 ;34(6):2027-37. Epub 2014 Nov 26. PMID: 25562151
BACKGROUND: Multidrug resistance (MDR) directly contributes to the clinical failure of chemotherapy in breast cancer (BCA).β-elemene is a natural antitumor drug from plants. We previously confirmed that MDR could be reversed by β-elemene. In this study, we intended to investigate the reversal effect of β-elemene on MDR in human BCA adriacin (Adr) -resistant MCF-7 cells (MCF-7/Adr) and docetaxel (Doc) - resistant MCF-7 cells (MCF-7/Doc) through the gene regulatory network.
METHODS: MTT-cytotoxic, miRNA microarray, Real-time quantitative PCR, Dual Luciferase Activity Assay, Western blot analysis were performed to investigate the impact ofβ-elemene on chemo-resistant BCA cell suvival, and its impact on the expression of chemo-resistance specific miRNA and the downstream target genes PTEN and Pgp.
RESULTS: Compared with the miRNAs expression profiles of MCF-7/Adr and MCF-7/Doc cell lines from our previous studies, there were 322 differentially expressed miRNAs in MCF-7/Adr and MCF-7/Doc breast cancer cells withβ-elemene intervention (50μM/L) for 30h, and 6 miRNAs were significantly up-regulated and 12 miRNAs were significantly down-regulated in both MCF-7/Adr and MCF-7/Doc. We have testified that 5 miRNA is related to MDR before, in this study, the expression of miR-34a, miR-222, miR-452 and miR-29a canlead to changes of the characteristics of chemo-resistant MCF-7/Adr and MCF-7/Doc. The PTEN expression under intervention of β-elemene was significantly increased and Pgp expression under β-elemene intervention was significantly decreased in both cell lines.
CONCLUSIONS: β-elemene could influence MDR related miRNA expression and subsequently regulate the expression of the target genes PTEN and Pgp, which may lead to reduction of the viability of the chemo-resistant breast cancer cells.