中文摘要：

本研究旨在观察4型含Bromo结构域蛋白（bromodomain-containing protein 4,BRD4）抑制剂GSK525762A对KU812细胞增殖及凋亡的影响及其机制.用GSK525762A 100、250、500、1000、2500和5000 nmol/L处理KU812细胞48和72 h,CCK-8法检测其对细胞增殖的影响;GSK525762A 1.0、2.5和5.0 μmol/L处理72 h,利用流式细胞术检测其对KU812细胞的凋亡诱导作用.将KU812细胞经DMSO和2.5 μmol/L的GSK525762A处理后,利用实时荧光定量PCR观察c-Myc、BCL-2、CDK6、BCL-xL、BAK和BAX基因的mRNA表达水平.结果表明,GSK525762A能显著抑制KU812细胞的增殖,且抑制作用存在量-效关系（r =0.970）和时-效关系（r=0.956）;GSK525762A能促进KU812细胞的凋亡;GSK525762A处理后促增殖基因c-Myc、CDK6和抗凋亡基因BCL-2和BCL-xL的mRNA较对照组降低,而促凋亡基因BAK和BAX的转录水平较对照组升高.结论：GSK525762A显著抑制KU812细胞的增殖并促进其凋亡,其机制可能与下调c-Myc、BCL-2、CDK6、BCL-xL的表达和上调BAK、BAX的表达有关.

英文摘要：

This study was purposed to investigate the effect of bromodomain-containing protein 4 （BRD4） inhibitor GSK525762A on the proliferation and apoptosis of chronic myeloid leukemia blast crisis KU812 cells and its mechanism.KU812 cells were treated with different concentrations of GSK525762A （100,250,500,1 000,2 500 and 5000 nmol/L） and the inhibitory effects of drug on KU812 cell proliferation after 48 and 72 hours were detected by using CCK-8 assay.KU812 cells were treated with 3 different concentrations of GSK525762A （1.0,2.5 and 5 μmoL/L） and the cell apoptosis after 72 hours were assayed by using flow cytometry.KU812 cells were treated with DMSO and 2.5 μmol/L GSK525762A,and the mRNA levels of C-MYC,BCL-2,CDK6,BCL-xL,BAK and BAX were determined by using quantitative reverse transcription polymerase chain reaction （qRT-PCR）.The results showed that GSK525762A could significantly inhibit the proliferation of KU812 cells and the inhibitory effect on KU812 cell proliferation was dependent on the dose-course and time-course of GSK525762A treatment.GSK525762A treatment could induce apoptosis of KU812 cells in a dose-dependent manner.After GSK525762A treatment,the mRNA levels of proliferation-promoting genes （C-MYC and CDK6） and pro-survival genes （BCL-2 and BCL-xL） decreased,while the transcription level of proapoptosis genes BAK and BAX increased,as compared to that of the control group.It is concluded that GSK525762A can inhibit the proliferation of KU812 cells and induce cell apoptosis possibly through depressing the transcription of CMYC,BCL-2,CDK6 and BCL-xL gene,and down-regulating BAK and BAX transcription.