高三尖杉酯碱联合survivin抑制剂YM155对人白血病K562细胞系增殖和凋亡的影响

Effects of homharringtonine plus survivin inhibitor YM155 on the proliferation and apoptosis of human leukemia cell line K562

目的:探讨高三尖杉酯碱(HHT)联合survivin抑制剂YM155对人白血病K562细胞系增殖抑制和诱导凋亡的作用及机制。方法:CCK法检测细胞增殖抑制率,依据中效原理及CalcuSyn软件评价HHT和YM155的联合治疗效果。设空白对照组、HHT组、YM155组和联合用药组,采用Annexin V/PI双染法以流式细胞仪检测细胞凋亡率,Western blot法检测survivin蛋白变化,以特异性荧光底物检测caspase-3、-8活性变化。结果:HHT和YM155单药均以浓度依赖方式抑制K562细胞生长,二者联合应用具有化疗协同作用(CI<1)。联合用药组K562细胞凋亡率明显高于单独用药组,且survivin蛋白表达显著下调(均P<0.05)。HHT单药及联合用药组诱导caspase-3、-8活化,而YM155单药未引起caspase-3、-8活性变化。结论:HHT和YM155联合应用于K562细胞具有化疗协同作用,通过下调survivin诱导K562细胞凋亡。

Objectives： To explore the combination applications of homharringtonine （HHT） and the survivin inhibitor YM155 on the proliferation and apoptosis of human leukemia cell line K562 and its mechanism. Methods： CCK-8 assay was used to determine the growth inhibition. The combination index CI of HHT and YM155 was cal- culated using the Chou-talalay methods by CalcuSyn software. The cells were divided into 4 groups：control group, HHT group,YM155 group,and combination group. The cell apoptosis rates were evaluated by flow cytometry. The expressions of associated proteins were detected by Western blot. Caspase-3 and -8 activities were determined using the specific fluorogenic substrates. Results： The inhibitory rates on cell growth by HHT and YM155 alone in creased in concertration-dependent manner. The application of H HT and YM155 had synergistic effect （CI〈1）. The apoptosis rate was higher in combination group than those of one drug group and the protein expression levels of survivin decreased remarkably in combination group （P〈0.05）. Caspase-3 and -8 were activated by HHT or combination treatment, but not by YM155. Conclusion： The combination treatment with HHT and YM155 on K562 cells has synergistic effect. The mechanism is related to the apoptosis induced through down-regulation of survivin.