激酶抑制剂DRB在骨髓瘤细胞中调控锌指转录因子IKZF1的机制研究

Mechanistic study of a kinase inhibitor DRB on the regulation of a zinc finger transcription factor IKZF1 in multiple myeloma cells

目的:研究激酶抑制剂调控多发性骨髓瘤细胞死亡关键蛋白锌指转录因子IKZF1的分子机制。方法:在两种多发性骨髓瘤细胞OPM2和U266中用酪蛋白激酶抑制剂DRB处理不同时间后,蛋白质免疫印迹实验检测IKZF1的表达变化,研究细胞凋亡相关蛋白在药物处理后的表达和激活情况;用漆黄素(fisetin)和凋亡酶抑制剂处理U266细胞后检测IKZF1、procaspase-3及其剪切体的变化。结果:激酶抑制剂DRB在OPM2细胞中但不在U266细胞中降低IKZF1、procaspase-9、procaspase-3、BID等蛋白的表达;漆黄素在U266细胞中激活细胞凋亡并导致IKZF1的剪切;凋亡酶抑制剂处理两细胞株后发现IKZF1剪切被抑制。结论:在多发性骨髓瘤细胞OPM2和U266中激活凋亡酶可以导致IKZF1的剪切和降解。

Objective： To explore the molecular mechanism by which a kinase inhibitor regulates the protein level of a zinc finger transcription factor IKZF1,which plays critical roles in determining the death of multiple myelomacells. Methods： IKZF1 in two myeloma cells OPM2 and U266 treated by DRB for different time was determined by western blotting. The procaspases,caspases,proapoptotic and antiapoptotic proteins were immunoblotted. IKZF1 was also monitored in U266 cells treated with fisetin in the absence or presence of caspase inhibitors. Results：IKZF1,procaspase-9 /3 and BID were cleaved in OPM2 cells but not in U266 cells after DRB treatment. Activation of apoptosis with fisetin in U266 cells also led to the cleavage of IKZF1. The cleavage of IKZF1 in two myeloma cell lines was blocked by caspase inhibitors. Conclusion： Activation of apoptotic pathway in two myeloma cells OPM2 and U266 leads to the cleavage and degradation of IKZF1.