选择性Bcl-2抑制剂ABT-199对乳腺癌细胞MDA-MB-231的放疗增敏作用

目的 研究ABT-199 对人乳腺癌细胞MDA-MB-231的放疗增敏作用,并探讨其作用机制. 方法 取对数期生长的MDA-MB-231细胞分成对照组、药物组、照射组及联合组(照射+ABT-199). 四甲基偶氮唑蓝(MTT)法检测不同剂量单纯照射和ABT-199 分别作用不同时间对MDA-MB-231细胞增殖的影响并计算20%抑制浓度( IC20 );流式细胞术检测 ABT-199 对 MDA-MB-231 细胞周期和凋亡的影响;Caspase活性试剂盒检测细胞 Caspase-3 活性变化;Western blot法检测凋亡相关蛋白Bcl-2、Bax、Bcl-xl的表达. 结果ABT-199对MDA-MB-231细胞有增殖抑制作用且有时间和浓度依赖性,随着ABT-199 浓度的升高, MDA-MB-231 细胞发生不同程度的G0/G1 期阻滞. 联合组较照射组细胞凋亡率明显增高(16. 9% vs 84. 5%),Bcl-2表达水平明显下调(P<0. 05),Bcl-xl变化不明显,同时Bax水平和胞内Caspase-3活性增高(P<0. 05). 结论 选择性Bcl-2抑制剂ABT-199可有效抑制人乳腺癌细胞系MDA-MB-231增殖,诱导细胞发生G0/G1 期阻滞及凋亡. IC20浓度的ABT-199 可明显提高MDA-MB-231细胞对放疗的敏感性.

Radiosensitization of breast cancer cells MDA-MB-231 with the selective Bcl-2 inhibitor ABT-199

Objective To study the radiosensitization effect of selective Bcl-2 inhibitor, ABT-199 in breast cancer cells MDA-MB-231 and to explore its possible mechanism. Methods The MDA-MB-231 cells in logarithmic phase were divided into control group, drug group, radiation group and combination group (radiation+ABT-199). The anti-proliferative effects of radiation and ABT-199 in MDA-MB-231 were measured respectively with MTT assay and the value of IC20 was calculated. The cell cycle arresting and apoptosis of MDA-MB-231 cells were measured by flow cytometry. Caspase-3 activity was assayed by caspase activity assay kit. The Bcl-2, Bax, Bcl-xl expression were detected by western blot. Results ABT-199 inhibited the proliferation of MDA-MB-231 in a time-dependent and dose-dependent manner. With the increasing of ABT-199 concentrations, MDA-MB-231 cells were blocked in G0/G1 phase. The apoptosis rate in combination group was significantly higher than radiation group ( 16. 9% vs 84. 5%) . Compared with the radiation group, Bcl-2 expression of the combination group were significantly reduced ( P<0. 05) and Bcl-xl expression showed no significant change, while its Bax expression and Caspase-3 activity in-creased ( P<0. 05 ) . Conclusion Bcl-2 selective inhibitor ABT-199 can effectively inhibit the proliferation of hu-man breast cancer cell line MDA-MB-231 and induce cell G0/G1 phase arrest and apoptosis. ABT-199 can signifi-cantly improve the radiosensitivity of MDA-MB-231 .