羟基喜树碱诱导SMMC-7721细胞凋亡时线粒体凋亡诱导因子的转位研究

目的研究羟基喜树碱诱导肝癌细胞株SMMC-7721凋亡时线粒体凋亡相关蛋白凋亡诱导因子表达及从线粒体发生核转位的变化.方法用80 μg/ml羟基喜树碱作用于肝癌细胞株SMMC-7721后,用吖啶橙/溴化乙啶染色法观察细胞凋亡现象;用电子显微镜观察线粒体超微结构;分别用逆转录聚合酶链反应、Western blot检测凋亡诱导因子在mRNA与蛋白质水平表达的变化;用激光共聚焦显微镜观察凋亡诱导因子在细胞凋亡时从线粒体到核的迁移变化.结果 80μg/ml羟基喜树碱作用SMMC-7721细胞后,吖啶橙/溴化乙啶荧光双重染色可见细胞体积缩小、细胞皱缩、核碎裂等典型细胞凋亡形态学改变;超微结构观察发现线粒体肿胀;细胞凋亡时凋亡诱导因子在mRNA与蛋白质水平上的表达与对照组细胞相比没有明显变化,但凋亡诱导因子发生了从线粒体到核的迁移. 结论羟基喜树碱可以通过线粒体途径诱导人肝癌细胞发生凋亡;在线粒体凋亡途径中,线粒体凋亡相关蛋白凋亡诱导因子从线粒体释放并发生核转位可能与羟基喜树碱诱导细胞凋亡密切相关.

Effect of hydroxycamptothecin on apoptosis-inducing factor (AIF) expression and on AIF translocation in human hepatocellular cancer cell SMMC-7721

Objective To study the effect of hydroxycamptothecin (HCPT) on apoptosis-inducing factor (AIF) expression and AIF translocation from mitochondria to the nucleus in human hepatoceller cancer cell SMMC-7721 during apoptosis. Methods After treatment with 80 mg/ml of HCPT, the cancer cells were stained with A0/EB to monitor their apoptosis. Their mitochondria was examined with electronmicroscopy and the AIF expression of the cells was tested by RT-PCR and Western blot. The translocation of AIF from mitochondria to the nucleus during apoptosis was analyzed by confocal microscopy. Results SMMC-7721 cells treated with HCPT showed chromatin condensation, nuclear fragmentation and mitochondria swelling. The mRNA and protein expression of AIF in treated and untreated SMMC-7721 cells were not significantly different. However, cells treated with 80 mg/ml HCPT for 6 h or 12 h showed massive translocation of AIF into the nuclei. Conclusion These results show the important role the mitochondrial pathway of apoptosis plays in HCPT-induced tumor cell death, at least in SMMC-7721 cells.