Effect of SIRT1 on the proliferation of ovarian cancer CAOV3 cells and its possible mechanism / 中国生化药物杂志

ABSTRACT

Objective To observe the effect of SIRT1 on the proliferation of ovarian cancer CAOV3 cells and its possible mechanism. Methods Ovarian cancer CAOV3 cells were transfected the Lipofectamine 2000 and were divided into normal control group,negative control group and SIRT1-siRNA group.The mRNA and protein expression levels of SIRT1 were detected by RT-PCR and Western blot.MTT method was used to detect the proliferation of RNA interference at 24h,48h and 72h,respectively.The distribution of CAOV3 cell cycle phase after RNA interference of SIRT1 for 72 hours was detected by flow cytometry.SIRT1,p53,p21 protein expression and p53 acetylation status were detected by Western blot with RNA interference of SIRT1 after 72 hours.The interaction between SIRT1 and p53 protein was verified by immunoprecipitation in CAOV3 cells.Results Compared with negative control group,the expression of mRNA and protein of SIRT1 in SIRT1-siRNA group decreased after transfection of SIRT1 for 72 hours.The survival rate of CAOV3 cells in SIRT1-siRNA group decreased significantly at 48 hours and 72 hours (P<0.01).The proportion of Sphase cells in CAOV3 cells transfected with SIRT1-siRNA for 72h was significantly decreased (P<0.01),while the G1 phase cells were significantly increased (P<0.01),and the cells arrested in the G1 phase.The expression of p53 and p21 proteins were significantly increased and the p53 was in higher acetylation status after transfection with SIRT1-siRNA for 72 hours ( P<0.01 ) .SIRT1 was interacted with p53 protein in CAOV3 cells confirmed by co-immunoprecipitation. Conclusion Downregulation of SIRT1 expression can inhibit the proliferation of ovarian cancer CAOV3 cells, which maybe connected with p53 at high acetylation status,and enhancing p53-dependent p21 transcriptional activation,thus blocking the cell cycle and inhibiting the cell proliferation.