紫杉醇诱导胃癌细胞凋亡及对端粒酶活性调节的关系

Paclitaxel Induces Apoptosis and Modulates Telomerase Activity of Human Gastric Carcinoma Cell Line

目的:研究紫杉醇对人SGC-7901胃癌细胞的诱导凋亡作用及对端粒酶活性调节的关系.方法:0.001～1uM的紫杉醇处理SGC-7901细胞后,用MTT法测定胃癌细胞的生长抑制率,甲苯胺蓝染色后光镜下观察细胞凋亡形态变化,流式细胞仪检测细胞周期、细胞凋亡率及bcl-2水平,半定量TRAP-银染法测定端粒酶活性变化.结果:0.01～1uM的紫杉醇对胃癌细胞均有明显抑制作用.抑制作用首先表现为G2/M期阻滞,继而出现细胞凋亡,且呈时间依赖性及剂量依赖性.对端粒酶活性的同步检测结果显示,紫杉醇在诱导细胞凋亡的同时伴随端粒酶活性下调,且抑制作用逐渐增强,24小时酶活性开始受抑制,72小时变为阴性.在这一过程中,bcl-2表达水平下降.结论:紫杉醇对胃癌细胞具有明显抑制作用,诱导细胞凋亡并抑制端粒酶活性可能是其发挥抗癌作用的机制之一,bcl-2参与了紫杉醇诱导的胃癌细胞凋亡过程中端粒酶活性的调控.

Purpose; To study the apoptosis induced by paclitaxel and modulation of paclitaxel on telomerase activity in human gastric carcinoma cell line SGC-7901. Methods: Human gastric carcinoma cell line SGC-7901 was treated with paclitaxel (0.001, 0.01, 0.1 and 1 μM) for 1-4 days. MTT assay was used to determine the cell growth inhibition rate, cell morphologic changs were examined under light microscope. Flow cytometry was used to examine bcl-2 gene and paclitaxel-induced apoptosis in gastric carcinoma cell line SGC-7901. Also telomerase activity was detected by semi-quantity TRAP assay at the same time. Results; Paclitaxels (0.01 - 1 μM) were cytotoxic to human gastric carcinoma cell in time-dependent and dose-dependent manner. SGC-7901 cell line treated with paclitaxel was induced cell cycle arrest at G2/M phase, leading to apoptosis. At the same time, decreased telomerase activity was detected in paclitaxel-induced apoptotic cell after 24 h, telomerase activity became negative after 72 h. The expression of bcl-2 gene was decreased after paclitaxel treatment. Conclusion: Paclitaxel is effective in growth inhibition on gastric cacinoma cell line. Paclitaxel-induced apoptosis and inhibition of telomerase activity may be one of the anti-cancer mechanisms, bcl-2 is involved in the regulation of telomerase activity during SGC-7901 cell line apoptosis induced by paclitaxel.