Effect of AQP-8 on cell apoptosis and expression of IAPs in human colon cancer HT-29 cells in vitro

doi:10.3969/j.issn.1002-7386.2041.22.005

Abstract：Objective To investigate the effects of aquaporin-8 ( AQP-8 ) on cell apoptosis and expression of inhibitors of apoptosis proteins( IAPs) by means of eukaryotic expression vector that expresses AQP-8 in human colon cancer HT-29 cells in vitro.Methods Human colon cancer HT-29 cells at logarithm growth period were used in the experiment. AQP-8 eukaryotic expression vector was constructed and transfected into HT-29 cells.Western Blot was used to detect the transfection efficiency;MTT assay was used to detect the cell growth inhibition rate;flow cytometry( FCM) was used to measure the cell apoptosis rate.The expression levels of mRNA and protein of IAPs including c-IAP1,c-IAP2,XIAP,NIAP,Survivin and Livin were detected by fluorescence quantitative Real-time RT-PCR and Western Blot.Results The results by Western Blot showed that the expression levels of AQP-8 were significantly up-regulated in colon cancer HT-29 cells after GFP-AQP-8 transfection ( P <0.05).MTT analysis showed that the proliferation inhibition rate was increased significantly in HT-29 cells after GFP-AQP-8 transfection,as compared with that in GFP-N1 control group ( P <0.05).FCM analysis showed that GFP-AQP-8 transfection obviously induced HT-29 cell apoptosis ( P <0.05 ) .The results of fluorescence Real-time quantitative RT-PCR and Western Blot showed that the expression levels of mRNA and protein of c-IAP1, c-IAP1, XIAP, Livin,and survivin in HT-29 cells were significantly decreased by AQP-8 overexpression ( P <0.05).However,the expression levels of NIAP mRNA and protein had no obvious change ( P >0.05).Conclusion The overexpression of AQP-8 can inhibit growth of HT-29 cell and can induce HT-29 cell apoptosis by down-regulating the expression levels of c-IAP1,c-IAP1,XIAP, Livin and survivin.