NDRG2基因启动子甲基化与肺腺癌细胞中mRNA表达相关性的实验研究

Promoter Methylation and Gene Expression of NDRG2 Gene in Lung Cancer Cells

目的:探讨肺腺癌细胞中NDRG2基因启动子甲基化状态及其与基因表达的关系。方法:甲基化焦磷酸测序技术检测启动子区域甲基化状态,荧光定量PCR技术检测不同药物浓度下培养细胞中NDRG2基因mRNA的表达水平,分析启动子区域甲基化与基因表达之间的关系。结果:在体外培养细胞中检测到NDRG2基因启动子区域呈现不同程度的甲基化,甲基化频率分别为肺癌A549细胞71.8%、GLC-82细胞86.1%、人脐静脉内皮ECV-304细胞36.8%、胃上皮GES-1细胞42.9%。NDRG2基因mRNA表达与其启动子甲基化程度成反比,甲基转移酶抑制剂5-杂氮-2-脱氧胞苷(5-Aza-CdR)作用于细胞后,A549和GLC-82细胞中NDRG2基因的mRNA转录明显上调,至72 h差异显著(P<0.05)。结论:肺腺癌细胞中NDRG2基因启动子CpG岛存在高甲基化,甲基化程度与该基因的表达具有负相关性,5-Aza-CdR能在一定程度上提高NDRG2的转录水平。

Objective： To investigate the relationship between NDRG2 gene promoter methylation and gene expression in lung cancer cells.Methods： NDRG2 promoter methylation was detected by pyrosequencing,NDRG2 mRNA expression were quantified by real-time PCR.Culture cells demethylation were processed by 5-Aza-CdR treatment.Results： The methylation frequency of NDRG2 promoter in lung cancer cells A549 was 71.8% and in GLC-82 cells was 86.1%.In control cells,the methylation frequency was 36.8% in ECV-304 cells and 42.9% in GES-1 cells respectively.NDRG2 mRNA expression were up-regulated from 24 to 72 h after 5-Aza-CdR treatment（P 0.05） in A549 and GLC-82 cells.Conclusion： NDRG2 promoter methylation was detected in the four tested cells.The methylation frequency in lung cancer cells was higher than in control cells.The promoter methylation of NDRG2 was probably responsible for its transcription silence in lung cancer cells,and 5-Aza-CdR can restore the transcription of NDRG2.