藤黄酸促进bax和p53表达诱导人肝癌细胞SMMC-7721凋亡

目的：观察藤黄酸(gambogic acids，GA)对肝癌细胞凋亡的诱导作用并探讨其分子作用机制。方法与结果：采用MTT比色法检测藤黄酸对人肝癌和人正常肝细胞增殖作用的影响，结果表明，藤黄酸对人肝细胞性肝癌SMMC-7721细胞株和QGY-7701细胞株有明显增殖抑制作用，并呈剂量依赖性，而对正常人肝组织L-02细胞株作用相对较弱；光镜及电镜形态学观察结果显示，给予GA后，肝癌细胞发生明显的细胞凋亡形态学变化，如细胞体积变小，细胞核固缩，出现凋亡小体等；采用RT-PCR和Western blotting方法检测bax mRNA以及bax和p53蛋白表达变化，结果表明GA可诱导bax mRNA及bax和D53蛋白表达上调；琼脂糖凝胶电泳显示，给予GA后，SMMC-7721裸小鼠移植瘤组织呈现典型的DNA ladder电泳梯状条带。结论：藤黄酸可显著抑制人肝癌细胞的增殖，其分子作用机制可能通过促进bax和p53表达上调，从而诱导人肝细胞性肝癌细胞凋亡。

Gambogic Acid Induced Apoptosis in Human Hepatoma SMMC-7721 Cells with p53 and Bax Up-regulated

AIM: To investigate Gambogic acid(GA) induced apoptosis in hepatoma cell lines and its mechanism. METHOD and RESULT: MTT assay showed that the proliferation of SMMC-7721 and QGY-7701 cells were markedly inhibited by GA in dose-dependent manner, while for the normal liver L-02 cells, the effect was lower. Under inverted-microscope and electronic microscope, typical morphological changes of apoptosis were observed, including condensed chromatin and a reduction in volume. RT-PCR and Western blotting were used to detect the changes of bax in mRNA and changes of bax and p53 in protein levels. The results indicated that the expression of bax and p53 were up-regulated by GA. Additional DNA fragmentation assay showed that GA induced apoptosis on SMMC-7721 nude mice xenografts. CONCLUSION: GA induced apoptosis in human hepatoma cells may be related with up-regulating the expressions of bax and p53.