ABSTRACT
ObjectiveTo investigate the effects of X-linked inhibitor of apoptosis (XIAP) siRNA or XIAP antagonist Embelin on the growth inhibition and apoptosis of hepatcellular cancer cell line HepG2,which was treated by tumor necrosis factor-related apoptosis (TRAIL). Methods HepG2 cells were tranfected either by XIAP siRNA or a negative control,followed by treatment with TRAIL,Embelin or a combination of the two.XIAP expression,cell growth,and caspase-3 activity were determined by Western blot,MTT assay and fluorescent caspase-3 assay,respectively.Cleaved PARP expression levels of were measured by Western blot.ResultsThe XIAP protein expression was significantly downregulated by transfection with XIAP siRNA.Compared with the negative control,the XIAP siRNA significantly inhibited the growth of HepG2 cells treated by 100ng/ml(6.8％ ±1.2％ vs.11.8％±4.0％,P＜0.05)and 1000 ng/ml (18.9％ ±2.0％ vs.26.6％ ±1.5％,P＜0.01)by TRAIL.TRAIL-induced caspase-3 activation and PARP cleavage were also increased significantly by XIAP siRNA transfection.In addition,Embelin also significantly inhibited cell growth (P＜0.01),activation of caspase-3 (P＜ 0.01) and TRAIL-induced PARP cleavage.Conclusions Both XIAP siRNA and Embelin may potentially contribute to clinical treatment of hepatocellular carcinoma.