5-氮杂-2’-脱氧胞苷对石英恶转细胞DNA依赖蛋白激酶基因去甲基化作用  

Effect of 5-Aza-dc on the DNA-PKcs demethylation and mRNA expression in M-16HBE cells induced by silica

作　　者：左昕[1] 田琳[1] 高艾[1] 牛丕业[1] 郭伟[1] 宋珊珊[1] 朱钟慧[1] 

机构地区：[1]首都医科大学公共卫生与家庭医学学院劳动卫生与环境卫生学系,北京100069

出　　处：《中国职业医学》2011年第2期99-101,共3页China Occupational Medicine

基　　金：国家自然科学基金资助项目(30872090);北京市教委资助项目(KM200810025021)

摘　　要：目的研究甲基化抑制剂5-氮杂-2’-脱氧胞苷(5-Aza-dc)对石英恶性转化人支气管上皮细胞系(M-16HBE)DNA依赖的蛋白激酶复合物催化亚单位(DNA-PKcs)启动子区甲基化状态和mRNA表达的影响。方法应用不同浓度的5-Aza-dc(分别为5、10、20μmol/L)处理M-16HBE细胞后,用甲基化特异性聚合酶链反应(Methylation specific PCR,MSP)方法检测DNA-PKcs基因启动子区甲基化状态,用反转录PCR(Reverse transcription-PCR,RT-PCR)检测DNA-PKcs基因mRNA表达情况。结果对照组细胞未发生DNA-PKcs甲基化,而M-16HBE组发生了DNA-PKcs完全甲基化。5-Aza-dc处理M-16HBE细胞后,DNA-PKcs基因甲基化逐渐降低、mRNA表达水平则逐渐增高,并呈剂量依赖趋势。结论启动子区DNA高甲基化是M-16HBE细胞DNA-PKcs基因表达下调的主要原因之一,甲基化抑制剂5-Aza-dc可逆转DNA-PKcs甲基化状态,从而上调DNA-PKcs基因的表达。Objective To detect the influence of DNA methylase inhibitor 5-aza-2＇-deoxycytidine（5-Aza-dc） on the methy lation status and the mRNA expression of DNA repair gene DNA-PK catalytic subunit（DNA-PKcs） in human bronchial epithelial cell line malignantly transformed by silica（M-16HBE）.Methods M-16HBE cells were treated with 5-Aza-dc at different concentrations：5,10,20 μmol/L.DNA-PKcs methylation status was identified by methylation specific PCR.DNA-PKcs mRNA expression was identified by RT-PCR.Results Methylation was not detected in 16HBE cells,while complete methylation was detected in M-16HBE cells.Methylation was reversed in M-16HBE cells after which were treated with different concentrations of 5-Aza-dc,changed from complete methylation into incomplete methylation.mRNA expression rose subsequently.Conclusion DNA-PKcs methylation is a major mechanism of expression down-regulation for DNA-PKcs gene of M-16HBE cells.Methylation inhibitors 5-Aza-dc can reverse DNA-PKcs methylation and upregulate the gene expression.

关 键 词：5-氮杂-2’-脱氧胞苷 DNA-PKCS DNA甲基化 石英 

分 类 号：R135.2[医药卫生—劳动卫生]