Vitamin C is essential for natuarl killer cell cytotoxicity against cancer cells. - GreenMedInfo Summary
Depletion of ascorbic acid impairs NK cell activity against ovarian cancer in a mouse model.
Immunobiology. 2012 Jan 2. Epub 2012 Jan 2. PMID: 22306178
Department of Anatomy, Chung-Ang University, College of Medicine, Seoul, Republic of Korea; Department of Anatomy, Seoul National University, College of Medicine, Seoul, Republic of Korea.
Ascorbic acid (Vitamin C) administration has been used to prevent infectious diseases in public or as a therapeutic agent by the physicians in treatment of several diseases. Ascorbic acid is also involved in immune cell functions and immune responses, although the mechanisms by which it exerts effects on immune cells against cancer cells are not fully understood at the normal plasma level. In this study, we used the mice lacking l-gulono-γ-lactone oxidase (Gulo), the enzyme required for the biosynthesis of ascorbic acid, to characterize the effects of ascorbic acid on NK cell cytotoxicity against ovarian cancer cells, MOSECs (murine ovarian surface epithelial cells). Gulo(-/-) mice depleted of ascorbic acid survived for a shorter time than the normal control or Gulo(-/-) mice supplemented with ascorbic acid after tumor challenge regardless of treatment with IL-2. CD69 and NKG2D expression was clearly reduced in NK cells isolated from mice depleted of ascorbic acid as compared to that in the normal control and the mice supplemented with ascorbic acid. We also observed that IFN-γ secretion by NK cells isolated from Gulo(-/-) mice depleted of ascorbic acid was decreased after NK cells were co-cultured with MOSECs. Furthermore, the mRNA expression of perforin and granzyme B genes was also significantly decreased in NK cells isolated from mice depleted of ascorbic acid. Taken together, our results suggest that ascorbic acid at the normal plasma concentration has an essential role in maintaining the NK cytotoxicity against cancer cells.