Influence of survivin gene RNA interference on cell apoptosis and the sensitivity to cisplatin in cervical cancer cell HeLa

Background and purpose:Survivin is a new member of the inhibitors of apoptosis(IAPs) family.It is disregulated in various malignancies including human cervical carcinoma.Reduction of the expression of Survivin has resulted in chemosensitization.In this study we observed the effect of survivin gene RNA interference(RNAi) on the sensitivity of cervical cancer cell HeLa to cisplatin.Methods:Hela cells(human cervical cancer cell line) was transfected with the recombined eukaryotic expression plasmid pSilencer2.1-s2 that contained human survivin gene siRNA by LipofectAMINE2000,then the positive clones were selected with G418,the expressions of survivin mRNA and its protein were evaluated by semi-quantitative RT-PCR and Western blot,respectively,caspase-3 activity was assessed by kinase activity test and apoptosis by flow cytometry and Hoechst staining,cell viability and 50% inhibitive concentration(IC_(50)) were measured by methyl thiazolyl tetrazolium(MTT) assay.Results:The positive clones was picked after incubating with G418 for 24 days.Compared with cells transfected with either negative control plasmid(HeLa-NC),pure plasmid(HeLa-U6 neo)or none,the expression level of survivin mRNA and its protein declined markedly in the cells transfected with pSilencer(2.1)-s2 plasmid(HeLa-s2) by 62.8% and 60.1%,respectively;the caspase-3 activity had been enhanced and A_(405) was(1.26)±0.04;the apoptotic rate was(29.2±1.4)% in HeLa-s2,much higher than the other groups(P0.05);HeLa-s2 cells was sensitized to cisplatin by pSilencer2.1-s2 plasmid transfection and the IC_(50) was calculated as 0.87±0.02ug/ml by MTT assay.Conclusions:RNAi for survivin gene can enhance caspase-3 activity,induce cell apoptosis and significantly increase cell sensitivity to cisplatin by inhibiting the expression of survivin in human cervical cancer cell line HeLa.