NDRG2通过BRD4/c-Myc通路抑制黏液表皮样癌细胞增殖及迁移侵袭的机制研究

The mechanism of NDRG2 in the inhibition of the proliferation,migration and invasion of mucoepidermoid carcinoma cells through BRD4/c-Myc pathway

目的:研究NDRG2基因抑制人黏液表皮样癌细胞增殖及迁移侵袭的调控机制。方法:建立MC3细胞过表达NDRG2和MEC1细胞敲降NDRG2模型,用Westernblot和Real-timePCR检测c-Myc蛋白和mRNA的表达;荧光素酶报告基因实验检测c-Myc启动子活性;染色质免疫共沉淀(ChIP)检测BRD4与c-Myc启动子结合活性;CCK-8试剂盒检测细胞增殖;Transwell检测细胞迁移侵袭。结果:过表达NDRG2的MC3细胞中c-MycmRNA和蛋白表达减少、c-Myc启动子活性降低、BRD4与c-Myc启动子结合活性降低;敲降NDRG2的MEC1细胞中c-MycmRNA和蛋白表达增加、c-Myc启动子活性升高、BRD4与c-Myc启动子结合活性升高;过表达NDRG2的MC3细胞增殖和转移能力降低,而同时过表达c-Myc后细胞活力恢复,敲降NDRG2的MEC1细胞增殖和转移能力增加,而同时敲降c-Myc表达后细胞活力被抑制。结论:NDRG2通过抑制BRD4与c-Myc结合抑制c-Myc表达,抑制黏液表皮样癌细胞的增殖和迁移侵袭能力。

Objective:To investigate the mechanism of NDRG2 in the inhibition of the proliferation,migration and invasion of human mucoepidermoid carcinoma cells.Methods:The models of MC3 cells with NDRG2 overexpression and MEC1 cells with NDRG2 knockdown were established.Protein and mRNA expressions were detected by Western blot and Real-time PCR,respectively.Promoter activity of c-Myc was tested by luciferase reporter assay.BRD4 occupancy on c-Myc promoter was detected by ChIP.Cell proliferation,migration and invasion were detected by CCK-8 assay and Transwell assay respectively.Results:NDRG2 overexpression in MC3 cells decreased c-Myc mRNA and protein expression,c-Myc promoter activity and BRD4 binding activity on c-Myc promoter.NDRG2 knockdown in MEC1 cells increased c-Myc mRNA and protein expression,c-Myc promoter activity and BRD4 binding activity on c-Myc promoter.The proliferation,migration and invasion abilities of MC3 cells were suppressed by NDRG2 overexpression.The cell viability was restored after c-Myc overexpression at the same time.The proliferation,migration and invasion abilities of MEC1 cells were increased by NDRG2 knockdown,and the cell viability was suppressed after c-Myc knockdown.Conclusion:NDRG2 inhibits the expression of c-Myc by inhibiting the binding of BRD4 to c-Myc promoter,thereby inhibits tumor cell proliferation,migration and invasion.