NS398对白血病细胞K562凋亡的时间和剂量效应机制(英文)

Dose-and time-dependent effects of selective cyclooxygenase-2 inhibitor NS398 on apoptosis of K562 leukemia cells

目的探讨非甾体药物选择性环氧合酶-2(COX-2)抑制剂NS398对白血病细胞株K562细胞增殖及凋亡的效应关系和机制。方法采用噻唑蓝还原法(MTT法)检测NS398对K562细胞增殖抑制作用,流式细胞仪(FCM)和单细胞凝胶电泳技术(cometassay)测定K562细胞的凋亡,免疫印迹实验检测相关蛋白的表达。结果 NS398抑制K562细胞增殖存在时间和剂量效应关系,各浓度间差异有显著性(P<0.05)。NS398激活caspase-3和caspase-9,促进P53蛋白的积聚、Bax蛋白表达的上调和Bcl-xL蛋白表达的下调,进而导致细胞色素C的释放,致使K562细胞凋亡。结论 NS398可抑制K562细胞增殖,其诱导细胞凋亡的途径可能经过P53介导Bax的Caspase-3、Caspase-9的激活,揭示COX-2抑制剂可能存在着一个影响细胞翻译的新机制。

【Objective】To observe the mechanism and effect of cyclooxygenase-2 inhibitor NS398 on proliferation and apoptosis of leukemia cell line K562. 【Methods】The various concentrations of NS398 were added into culture media system to induce apoptosis of leukemia cell line K562. The K562 cell inhibition and apoptosis were detected by MTT assay, flow cytometry and comet assay. Western blot analysis was applied to determination of interrelated protein expression in K562 cells.【Results】NS398 inhibited proliferation and induced apoptosis of leukemia cell line K562 in a dose-and timedependent manner. There were singificantly differences among the various concentration groups （P 0.05）. NS398 stimulated caspase-3 and caspase-9 expression at protein level in K562 cells, and promoted accumulation of P53 protein, Bax over-expression and Bcl-xL down-expression.【Conclusion】NS398 significantly inhibits the proliferation and induces apoptosis of K562 cells. It can be concluded that NS398 enhances caspase-3 and caspase-9 expression via post-translational regulation, and provides a new mechanism by which specific COX-2 inhibitors suppress proliferation of leukemia cells. Mechanisms of leukemia cell line K562 apoptosis may be involved in accumulation of Bax by p53 expression and up-reugulated caspase-3 and caspase-9.