The Anti-tumor Activity of Vitamin C via the Increase of Fas (CD95) and MHC I Expression on Human Stomach Cancer Cell Line, SNU1.
BACKGROUND
It is already known that high concentration of vitamin C induces apoptosis on tumor cells. However, there is no report regarding the function of vitamin C on the modulation of immune susceptibility of cancer. Therefore, we investigated whether vitamin C can modulate immune susceptibility of tumor cells, especially on the induction of Fas-mediated apoptosis.


METHODS
First, the optimal concentration of vitamin C, which cannot induce damages on tumor cells for 36 hrs. We found that 2 mM of vitamin C did not show harmful effect. In addition, the optimal concentration of agonistic anti-Fas Abs for 18 hrs was examined.


RESULTS
As a result, 400 ng/ml of agonistic anti-Fas Abs did not induce apoptosis on tumor cells. Next, we tried to find the effect of 2 mM of vitamin C on the modulation of the susceptibility to agonistic anti-Fas Abs. When tumor cells were cultured with 400 ng/ml of agonistic anti-Fas Abs for 18 hrs, after pre-treatment with 2 mM of vitamin C for 24 hrs, viability of cells was decreased. Interestingly, we found that the expression of Fas (CD95) and MHC class I was increased by the treatment of vitamin C.


CONCLUSIONS
Taken together, vitamin C increases the susceptibility of tumor cells to anti-Fas Abs and the expression of Fas (CD95) and MHC class I on tumor cells.
Department of Anatomy and Tumor Immunity Medical Research Center, Seoul National University College of Medicine, Seoul 110-799, Korea.
Yeonsil
Y
Yu
Seyeon
S
Bae
Hyemin
H
Kim
Yejin
Y
Kim
Nag Bum
NB
Chu
Nag Kyun
NK
Chu
Jae Seung
JS
Kang
Wang Jae
WJ
Lee