XIAPsiRNA、Embelin对TRAIL诱导肝癌细胞生长抑制和细胞凋亡的影响

The effects of XIAP siRNA and embelin on TRAIL-induced growth inhibition and apoptosis in hepatocar-cinoma cells

目的研究X-连锁凋亡抑制蛋白（X-linked inhibitor of apoptosis，XIAP）siRNA或x1AP拮抗剂Embelin对肿瘤坏死因子相关凋亡诱导配体（tumor necros isfactor-relatedapoptosis—in—ducingligand，TRAIL）所致肝癌细胞HepG2生长抑制和细胞凋亡的影响。方法HepG2细胞转染xIAPsiRNA或者阴性对照，然后给予TRAIL处理。此外，HepG2细胞给予TRAIL、Embelin或者联合处理。XIAP表达水平变化、生长抑制、caspase-3活性分别用Westernblot、MTT测定、caspase-3荧光法检测。切割PARP的表达水平用Westernblot测定。结果XIAP蛋白表达水平在转染XIAPsiRNA后显著下调。与阴性对照相比，XIAPsiRNA显著增强TRAIL在100ng／ml（6．8％4-1．2％比11．8％±4．0％，P〈0．05）和1000ng／ml（18．9％±2．0％比26．6％±1．5％，P〈0．01）的生长抑制作用。在转染xIAPsiRNA后，TRAIL诱导caspase-3的活性和PARP的切割显著增强。此外，Embe—lin显著增强TRAIL对HepG2细胞的生长抑制（P〈0．01）、caspase-3活化（P〈0．01）和PAPR切割。结论XIAPsiRNA或Embelin在肝细胞癌的临床治疗方面具有潜在应用前景。

Objective To 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 cel[s 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. Results The XIAP protein expression was significantly downregulated by transfection with XIAP siRNA. Compared with the negative con-trol, 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）and1000 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.