TRAIL联合喜树碱体外诱导肝癌细胞凋亡的研究

目的探讨喜树碱增加TRAIL诱导肝癌细胞HepG2和Hep3B凋亡能力的分子机制。方法应用流式细胞仪分析TRAIL单独或联合应用喜树碱对肝癌细胞系HepG2和Hep3B细胞凋亡的影响；Western blot检测HepG2和Hep3B细胞在处理前后凋亡信号传导蛋白caspase-8，caspase-3，caspase-9，DR4，DR5，DcRl，c—FLIP，RIP，cytc，Smac和Bid表达的变化。结果喜树碱能增强TRAIL诱导肝癌细胞凋亡的能力，两者联用具有明显的协同作用。喜树碱预先处理能下调c—FLIP及RIP的表达及增加cytc，Smac，Bid的表达，但对DR4，DR5，DcRl的表达无明显影响。结论TRAIL联合喜树碱可以诱导肝癌细胞凋亡；其机制是下调c—FLIP及RIP的表达，活化凋亡发生的死亡受体通路，上调Bid的表达激活线粒体通路。死亡受体的表达不参与这一变化过程。

Study of TRAIL combined with camptothecin in induction of apoptosis in hepatocellular carcinoma cell lines

Objective To investigate the molecular mechanism of camptothecin enhancement of TRAIL-induced apoptosis in hepatocellular carcinoma cell lines. Methods The HepG2 and Hep3 B cell cycles were analysed by flow cytometry after co-treated with camptothecin and TRAIL, and the expression of signal transduction protein, such as Caspase-8, Caspase-3, Caspase-9, DR4, DRS, DcR1, c-FLIP, RIP, Cytc, Smac, Bid were detected by Western blot before and after the treatment. Results Pretreatment with lower dose of Camptothecin could increase the sensitivity of HepG2 and Hep3B cells to TRAIL-induced apoptosis, and could downregulate the expression of c-FLIP and RIP, upregulate the expression of Cytc, Smac and Bid, but had no effect on the expression of DR4, DR5 and DcR1. Conclusions Camptothecin could sensitize HepG2 and Hep3B cells to TRAIL-induced apoptosis, and the mechanism is by downregulation of c-FLIP and RIP, activation of apoptosis death receptor pathway, upregulation of Bid and amplification of the mitochondrial pathway. The expression of death receptor not involved in this process.