Silencing SIRT1 Gene By SiRNA Affects The Proliferation And Apoptosis Of Cervical Cancer Cells HeLa

Objective Sirtuins are class III histone deacetylases with homology to the yeast silent information regulator 2.1t has been reported that SIRT1 plays a critical role in tumor progression and it might be a novel epigenetic therapeutic target for human cancer.The purpose of this study was to investigate the effect of RNA interference targeting SIRT1 gene on the proliferation,apoptosis and Notch signaling pathway in human cervical cancer HeLa cells by chemically synthesized small interference RNA transfected into HeLa cellsMethods Various concentrations of siRNA SIRT1(15 nmol/L,30 nmol/L,45 nmol/L)was transfected into HeLa cells to optimize the transfection condition.The cell morphology was observed under the reverse phase microscope,the level of SIRT1 mRNA was detected by RT-PCR.HeLa cells were cultured in vitro and divided into four goups:normal control group,siRNA negative control group,transfection reagent RNAiMAX control and siRNA SIRT1 group.The level of SIRT1 mRNAand protein was measured by RT-PCR and Western blot respectively.The cell proliferation was assessed by CCK-8 method,the apoptosis was evaluated by Hoechst fluorochrome staining and flow cytometry;apoptosis related proteinP53,P21,Survivin and Notch signaling pathway protein Notch1,Hes1,cyclin D1 were detected by Western blot.Results 30 nmol/L siRNA SIRT1 was the most effective in RNA interference measured by RT-PCR;RT-PCR and Western blot assay revealed that in the siRNA SIRT1 transfection group,the SIRT1 mRNA and protein expression was significantly lower than that in the control groups,the CCK-8 showed the growth of HeLa cells was inhibited in the siRNA SIRT1 transfection group,' the morphology of cell apoptosis was observed by Hoechst 33258,flow cytometry displayed 15.9%in siRNA SIRT1 group,compared with only 3.9%in siRNA negative control group.The down-regulation of SIRT1 gene also increased the relative expression of apoptosis related protein P53,P21 and decreased the expression of Survivin protein(p<0.05),the relative expression amount of Notch1,Hes1,cyclinDl was increased.Conclusion Chemically synthesized small interference RNA targeting SIRT1 gene not only inhibited expression of SIRT1 mRNA and protein,but also remarkablely restrained proliferation and induced apoptosis in HeLa cells,which was associated with P53?P21?Survivin and Notch1 pathways.Further studies are required to investigate the mechanism of siRNA SIRT1 induced apoptosis in HeLa cells.