Abstract:

Objective To explore the growth inhibition  of survivin specific siRNA on hepatocellula carcinoma HepG2 cells in vitro and to investigate the growth inhibition  of survivin specific siRNA carried by attenuated Salmonella typhimurium on subcutaneous hepatocellular carcinoma in nude mice and its mechanism.Methods According to the expression of vector siRNA, the lipofectin control group and plasmid control group were transfected to HepG2 cells.The expressions of survivin mRNA and protein were detected by RT-PCR and Western blotting respectively.The proliferation abilities of cells were measured by MTT,and the cell cycle and apoptosis level were detected by flow cytometry (FCM).The subcutaneous hepatocellular carcinoma model was  set up in nude mice and the survivin specific siRNA carrid by attenuated Salmonella typhimurium  was injected into abdominal of mice and the growth inhibition of cells was observed.The expression of survivin was detected by immunohistochemistry and the apoptosis  was detected by TUNEL staining.Results After 48 h  transfection,the level of  survivin mRNA in the cells in siRNA group was (32.0±6.2)% and (27.8±4.6)% of those  in lipofectin control group and plasmid control group,respectively;and expression of survivin protein was (27.3±4.0)% and (20.8±2.8)% of inlipofecton control group and plasmid control group, respectively.The proliferation rate of  the  cells in survivn siRNA group was (29.2±4.8)% of that in lipofectin group.The cell proportion  in  G1 phase in survivin siRNA group was significantly higher than that in  two control groups,while the cell proportion in S phase was  lower(P<0.05).Subcutaneous hepatocellular carcinoma model was successfully set up  in nude mice, and after injected with survivin siRNA carried by specific  attenuated Salmonella typhimurium the growth rate was lower in siRNA group than the others (P<0.05).The expression of survivin in survivin siRNA group was lower than that in controls detected by immunohistochemical  method. The apoptotic rate of the cells was  increased obviously than those in controls detected by TUNEL (P<0.05).Conclusion Survivin specific siRNA could inhibit the proliferation of liver cancer HepG2 cells and promote the apoptosis in vitro and survivin specific siRNA carried by attenuated Salmonella typhimurium  could inhibit the growth of liver subcutaneous tumor and the mechanism may be related to the apoptosis.

Key words:  RNA interference;survivin;liver neoplasms;HepG2;cell apoptosis