硫利达嗪对乳腺癌细胞MDA-MB-231和MCF-7的杀伤效应

目的观察硫利达嗪对人乳腺癌细胞MDA-MB-231和MCF-7的凋亡作用，并探讨其机制。方法采用MTT法测定硫利达嗪对细胞的抑制作用，计算半数抑制浓度( IC50)；流式细胞术检测硫利达嗪对细胞周期分布和凋亡的影响；比色法测定药物对细胞Caspase-3活性的影响；West-ern blot法检测凋亡调节蛋白Bcl-2、Bax表达的变化。结果
　　硫利达嗪作用24 h后， MDA-MB-231、MCF-7细胞增殖明显呈剂量依赖性抑制，其IC50为18、22μmol/L。流式细胞术结果显示，随着加入硫利达嗪浓度的提高， MDA-MB-231、MCF-7细胞均发生不同程度的G0/G1期阻滞、细胞凋亡程度增加及伴随胞内Caspase-3活性增加。各实验组与对照组比较，差异均有统计学意义(P<0．01)。 Western blot法结果显示随着药物浓度的增加，抗凋亡蛋白Bcl-2表达下调、促凋亡蛋白Bax表达明显上调，各实验组与对照组相比，差异有统计学意义( P <0．01)。结论硫利达嗪对乳腺癌细胞MDA-MB-231、MCF-7有显著的增殖抑制作用且可显著诱导肿瘤细胞发生G0/G1期阻滞及凋亡，伴随Caspase-3活性的上调，其毒性机制可能与肿瘤细胞内抗凋亡蛋白 Bcl-2下调、Bax上调有关。

Killing effect of thioridazine on the proliferation of breast cancer cells MDA-MB-231 and MCF-7

Objectives To investigate the anti-proliferative and apoptosis-inducing effects and the possible molecular mechanisms of thioridazine on breast cancer cell lines MDA-MB-231 and MCF-7. Methods The anti-proliferative effects of thioridazine on MDA-MB-231 and MCF-7 cells were measured with MTT and the values of IC50 were calcu-lated. Flow cytometry was used to measure the cell cycle arresting and apoptosis . Caspase -3 activity assay kit was
performed to detect Caspase-3 activity levels. The expression changes of the Bcl-2 and Bax were detected by western blot. Results After treated with thioridazine for 24 h, MDA-MB-231 and MCF-7 cells were significantly inhibited by the drug extracts. The values of IC50 were respectively 18μmol/L and 22μmol/L. Flow cytometry showed cells’ G0/G1 phase arrest along with an increase of apoptosis and intracellular Caspase-3 activity with the increase of thio-ridazine concentration. Western blot showed concentration-dependant decrease in Bcl-2 and increase in Bax proteins. Each experimental group compared with the control group, the differences were statistically significant (P<0. 01). Conclusion Thioridazine has obvious cytotoxic effect on breast cancer cells MDA-MB-231 and MCF-7. It obviously induces breast cancer cells G0/G1 phase arresting and apoptosis, accompanied by up-regulation of Caspase-3 activity. The mechanism may be related to the down-regulation of Bcl-2 and up-regulation of Bax.