Caspase-3和Bcl-2在白血病细胞株凋亡过程中的表达及其与多药耐药的关系

目的研究Caspase-3在阿霉素(ADR)诱导的K562和K562/AO2细胞株凋亡过程中对Bcl-2蛋白表达的调控,探讨两者相互作用在白血病多药耐药中的分子机制。方法原位细胞凋亡检测法观察凋亡细胞的形态学改变;流式细胞仪测定凋亡率及Bcl-2蛋白的表达;酶显色活性分析法测定Caspase-3的活性。结果①K562细胞株的凋亡率对ADR呈时间、剂量依赖关系,K562/AO2细胞株则无此依赖关系。②未加Caspase-3抑制剂的K562细胞株Bcl-2阳性表达率和Caspase-3活性对ADR呈时间、剂量依赖关系;加入抑制剂的则无此关系,但作用48 h后Bcl-2阳性表达率下降,Caspase-3活性上升。无论加入Caspase-3抑制剂与否,K562/AO2细胞株的Caspase-3活性和Bcl-2阳性表达率均无变化。结论Caspase-3的变化能引起Bcl-2蛋白表达水平的变化,二者与凋亡关系密切,并在多药耐药中发挥重要作用。

Expression of Caspase-3 and Bcl-2 in leukaemia cell apoptosis and its significance in multiple-drug resistance

Objective To study the regulative role of Caspasc-3 on the Bcl-2 protein cxpression in the process of K562 and K562/AO2 cell apoptosis induced by adriamycin, in order to probe into the roles of Caspase-3 and Bcl- 2 in the molecular mechanism of the leukemia multiple-drug resistance. Methods The tcrminal dcoxynuclcotidyl transferase-mediated dUTP nick end labeling method was used to obscrvc the morphological changc of the apoptotic cells. Flow cytometry and the enzyme colorimctric activity assay methods wcrc used to cxaminc the rate of cell apoptosis, the Bcl-2 protein expression level and the Caspasc-3 activity. Results OThc cell apoptosis rate had a time- and dosage-dependent relation with adriamycin in thc K562 cell strain. The K562/AO2 cell strain did not have such characteristic. OThc Caspase-3 activity and the Bcl-2 protein expression level of K562 cell strain without the Caspase-3 inhibitor had a time- and dosage-dependent relation with adriamycin . There was no such relation when the inhibitor is added, but after bcing affected for 48 hours, the Bcl-2 protcin cxprcssion level dccrcascd and the activity of Caspase-3 increased. However, the Caspasc-3 activity and the Bcl-2 protcin cxprcssion level of the K562/ AO2 cell strain affected by ADR with or without the Caspasc-3 inhibitor showed no changes. Conclusion The change of Caspasc-3 can cause the change of the Bcl-2 protein cxprcssion level, and they arc closely related to apoptosis and have an important effect on multi-drug resistancc.