溴结构域蛋白4抑制剂GSK525762A对急性B淋巴细胞白血病细胞增殖和凋亡的影响及可能机制

Effect of bromdomain protein 4 inhibitor GSK525762A on the proliferation and apoptosis of B-cell acute lymphoblastic leukemia cells and its mechanism

目的 探究溴结构域蛋白4（BRD4）抑制剂对急性B淋巴细胞白血病细胞生物学行为的影响及可能机制.方法 用BRD4抑制剂GSK525762A抑制急性B淋巴细胞白血病细胞株RS4; 11细胞BRD4活性,并以急性T淋巴细胞白血病细胞株Jurkat细胞作对照.采用CCK-8法检测其对细胞增殖的影响;用Annexin Ⅴ/7-AAD标记,流式细胞术检测细胞凋亡;荧光定量PCR检测抗凋亡基因c-myc、Bcl-2、CDK6和促凋亡基因Bad、Bak、Bax的转录水平;Western blot检测Bcl-2及Bak蛋白的表达.结果 不同浓度GSK525762A对RS4; 11细胞增殖均有抑制作用,且呈时间和剂量依赖性,作用48、72 h其半数抑制率分别为6.174和1.996 μmol/L.与DMSO处理组比较,GSK525762A处理后RS4; 11细胞c-myc、Bcl-2、CDK6mRNA转录水平降低,而Bad、Bak、Bax mRNA转录水平升高,且Bcl-2蛋白表达水平下调,Bak蛋白表达水平上调.而GSK525762A对Jurkat细胞的增殖抑制作用并不明显.结论 GSK525762A可抑制RS4; 11细胞的增殖,并促进其凋亡;该作用可能通过下调Bcl-2表达,诱导白血病细胞凋亡而实现的.

Objective To investigate the effect of bromdomain protein 4 （BRD4） inhibitor GSK525762A on the proliferation,apoptosis of B-cell acute lymphoblastic leukemia cell line RS4; 11 cells,and to further explore the mechanism.Methods Compared with Jurkat leukemia cells,the activity of BRD4 on RS4; 11 cells were inhibited by the inhibitor GSK525762A.The inhibitory effects of BRD4 on RS4; 11 cells were measured by CCK-8 test and the apoptosis of those cells was determined by Annexin Ⅴ/7-AAD dyeing using flow cytometry.The transcripts of anti-apoptotic genes c-myc,Bcl-2,CDK6 and proapoptotic genes Bad,Bak,Bax were detected by quantitative PCR,and the expression of Bcl-2 and Bak proteins were detected via Western blot.Results Proliferation of RS4;11 cells could be inhibited by GSK525762A in a time-and dose-dependent manner,and the inhibitory IC50 at 48 and 72 h was 6.174 and 1.996 μmol/L,respectively.Compared with DMSO in control group,the levels of c-myc,Bcl-2 and CDK6 mRNA transcripts in RS4; 11 cells were reduced in GSK525762A treated group,while the levels of Bad,Bak,Bax mRNA transcripts were enhanced,moreover,Bcl-2 protein levels decreased and Bak protein levels increased.However,the inhibitory effect of GSK525762A on Jurkat cells proliferation was not obvious.Conclusion GSK525762A can inhibit the proliferation of RS4;11 cells and promoted cells apoptosis.The possible mechanisms underlying this phenomenon might be achieved via downregulation of Bcl-2 protein induced apoptosis of leukemia cells.