关键词: FasL, RNA干扰, CTL, 胃癌细胞, 免疫逃避

Abstract: Objective To verify the FasL expression of gastric cancer cells that induces tumor-specific CD8⁺CTL apoptosis mediates the immune evasion and prove RNA interference silences the FasL expression of gastric cancer cells can enhance antitumor function by increasing the number of tumor-specific lymphocytes. Methods Targeted FasL shRNA was design and screened to transfect gastric cancer cells by using liposome to silence the FasL expression. The experimental group（transfect targeted plasmid）, negative group and （transfect idler plasmid）blank group（without transfect） were set up,and then observing the effects of gastric cancer cells on inducing tumor-specific CTL apoptosis and antitumor function in the cell co-culture system with tumor-specific CD8⁺CTL. The FasL expression in gastric cancer cells was detected by flow cytometry. And the results of co-culture with gastric cancer cells and tumor-specific CD8⁺CTL were determined by MTT method. Results In the experimental group, those gastric cancer cells transfected by FasL-siRNA expressed a lower level of FasL which was significant in statistics compared with blank group. Compared with negative group and blank group, there existed more lymphocytes in the experimental group （differences between groups were significant in statistics, P<0.05）. Conclusion In the present study, Using RNA interference reduced the FasL expression of gastric cancer cells that enhanced the function of lymphocytes killing cancer cells.

Key words: gastric cancer cells, RNA interference, immune evasion, CTL, FasL