DNA去甲基化对肝细胞人端粒酶逆转录酶上调的研究  

DNA Demethylation induced by 5'-aza-dC Upregulates human telomerase reverse transcriptase in liver cell line SMMC-7721

作　　者：李正友[1] 张长松[2] 郭献灵[1] 程越[3] 卜欣欣[1] 李蓉[3] 贾凤岐[3] 李云龙[1] 吴孟超[3] 卫立辛[3] 

机构地区：[1]山东师范大学生命科学学院,济南市250014 [2]汕头大学医学院预防医学教研室 [3]第二军医大学东方肝胆外科研究所肿瘤免疫与基因治疗中心

出　　处：《中国肿瘤临床》2007年第2期61-64,共4页Chinese Journal of Clinical Oncology

基　　金：国家自然科学基金(编号:39471994);上海市科委基础研究重大项目(编号:04DZ14006);上海市科委浦江人才计划项目资助(编号:05PJ14010)

摘　　要：目的:观察肝细胞系L02及肝癌细胞系SMMC-7721中人端粒酶逆转录酶(human telomerase reverse transcriptase,hTERT)的表达与DNA甲基化修饰之间的相关性,观察5-杂氮胞苷(5'-aza-dC)去甲基化对肝细胞系hTERT表达和端粒酶活性的影响。方法:应用甲基化特异性PCR(Methylation-specific PCR,MSP)分析肝细胞系L02和肝癌细胞SMMC-7721中hTERT的甲基化状态,采用RT-PCR和TRAP-ELISA法检测5'-aza-dC干预对培养细胞hTERT mRNA表达及端粒酶活性的影响。结果:肝细胞系L02中hTERT有甲基化修饰,5'-aza-dC去甲基化处理上调hTERT mRNA表达并呈现端粒酶活性升高;肝癌细胞系SMMC-7721中hTERT则没有甲基化修饰,5'-aza-dC去甲基化处理对其hTERT表达和端粒酶活性无影响。结论:肝细胞中DNA甲基化可能参与抑制肝细胞hTERT的表达,hTERT去甲基化可能是肝癌发生发展的重要机制之一。Objective： To investigate the relationship between DNA methylation and the expression of human telomerase reverse transcriptase （hTERT） in normal liver L02 cells and hepatocellular carcinoma cell line SMMC-7721 and to study the effect of demethylation induced with 5＇-aza-dC by observing hTERT expression and telomerase activity. Methods： The methylation pattern of hTERT in cell lines was assayed by methylation-specific PCR （MSP）. Demethylation in cultured cells was induced by adding 5＇-aza-dC. The expression of hTERT was measured using RT-PCR and telomerase activity was detected by TRAP-ELISA. Results： In the L02 cells the hTERT promoter was methylated and the cells had decreased hTERT expression, while the expression level of hTERT was much higher in the SMMC-7721 cells. The expression of hTERT was upregulated and telomerase activity was increased in L02 cells after demethylation. Conclusion： hTERT expression may be repressed by methylation of its promoter, and abnormal demethylation of the hTERT promoter may play an important role in the development of hepatocellular carcinoma.

关 键 词：肝癌 DNA甲基化 人端粒酶逆转录酶 5-杂氯胞苷 

分 类 号：R735.7[医药卫生—肿瘤]