Effects of vitamin E succinate on the expression of Fas and PCNA proteins in human gastric carcinoma cells and its clinical significance

AIM: To investigate the effects of vitamin E succinate (VES) on the expression of Fas and PCNA proteins as well as its clinical significance in human gastric carcinoma, and to explore the mechanism of VES-induced inhibition of gastric carcinoma cell growth. METHODS: Immunohistochemical methods were used to detect Fas and PCNA expression both in human gastric cancer SGC-7901 cells treated with VES at different doses and in human gastric carcinoma tissues. RESULTS: After the SGC-7901 cells were treated with VES at 5, 10, 20 mg/L for 48 h, the positive rates of Fas expression were 16%, 27% and 48%, respectively, significantly increased compared to that of control group (P< 0.05); while the positive rates of PCNA expression in groups treated with different doses of VES were 20%, 18% and 7%, respectively, which were significantly decreased compared to that of the control group (P<0.05). In human gastric carcinoma tissues, the Fas positive expression rate was 42.4%(25/59), which declined with the decrease in the degree of tumor differentiation (P<0.05) and with the existence of lymph node metastasis (P<0.001). While the PCNA positive expression rate was 91.5%(54/59), no relationship was observed between PCNA expression and clinicopathologic parameters. CONCLUSION: VES inhibited the growth of gastric cancer cells by inducing Fas expression and inhibiting PCNA expression. It is, therefore, considered that the expression of Fas and PCNA genes, through tumor cell apoptosis and proliferation, respectively, may be useful as a clinical predictive index in the application of VES to gastric carcinoma therapy, where as Fas may be of more value than PCNA.