Abstract: Objective To investigate the effect of inhibiting Mcl-1 gene expression on the biological behavior of gastric cancer cell MGC-803 by using a small interference RNA(siRNA)strategy. Methods Synthesized siRNA targeting Mcl-1(Mcl-1siRNA group) was transfected into MGC-803 cells,additionally,MGC-803 cells transfected with negative siRNA(Mcl-1siRNA-NC group),MGC-803 cells transfected with Lipofectamine 2000（liposomes control group）and vacant MGC-803 cells（blank control group） were used as controls.MTT was adapted to investigate the proliferation of MGC-803 cells after transfection of Mcl-1 siRNA. After 48h transfection of Mcl-1 siRNA, the flow cytometry(FCM) was used to examine the apoptosis cells in the four groups. Cell cycle was detected by FCM in different groups. Polycarbonate membrane transwell chamber was used for detecting the abilities of invasion and migration of the cell line. Results The absorption value of MGC-803 cells decreased greatly after transfected with Mcl-1siRNA for 24、48 and 72 h compared to those in control groups(P<0.05); after transfected 48h, apoptosis rate in Mcl-1siRNA group was higher than in the blank control group, liposomes control group and Mcl-1siRNA-NC group(%:19.61±1.66 vs 3.69±0.37 vs 3.54±0.47 vs 3.68±0.55,F=12.230,P＜0.05),G0/G1 [(41.03±1.86)%] and G2 / M phase ratio [(1.80± 0.46)%] in Mcl-1 siRNA group were lower than in the three control groups, S phase ratio [(57.17±1.72)%] was higher than in three control groups(P<0.05). Transmembrane cell number of Mcl-1 siRNA group in polycarbonate membrane transwell chamber(42.00±4.00,76.33±3.51 respectively)were less than of the blank control group(79.33±3.51,108.00±3.61 respectively),liposome control group(74.67±2.52,110.67±4.04 respectively)and negative control group (77.33±3.06,109.33±4.51 respectively). However,there was no significant difference in above index among the control groups. Conclusion Inhibition the expression of Mcl-1 can effectively supress the growth, invasion and migration, and can promote apoptosis in gastric cancer cells.

Key words: Stomach Neoplasms, RNA, Small Interfering, Cell Proliferation, Cell Apoptosis, Cell invasion, Cell Migration, siRNA