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目的探讨基因甲基化在肺癌发生中的作用。方法南京医科大学附属南京第一医院呼吸科、复旦大学附属中山医院肺科和上海市肿瘤研究所于2004年10月至2005年12月应用甲基化特异性的多聚酶链反应(MSP)和RT-PCR检测甲基化的发生和mRNA的转录水平。结果肺癌细胞株A549部分甲基化的靶点包括p16INK4a、p73、RASSF1a和CDH1等,完全甲基化的靶点包括MGMT、CDH13等;SH-77部分甲基化的靶点包括p16INK4a、p73、WT1和CDH1等,完全甲基化的靶点包括RASSF1a和MGMT;SPC-A1部分甲基化的靶点包括p16INK4a、p73、CDH1、MYOD1和CDH13等,完全甲基化的靶点包括WT1和RAR-β。RASSF1a、WT1、MYOD1、MGMT和RAR-β等5个基因发生甲基化的细胞株其mRNA的转录水平均低于未发生甲基化的细胞株甚至完全不转录。结论NSCLC细胞株中抑癌基因经常发生启动子CpG岛的甲基化,并且甲基化可能与抑癌基因mRNA转录水平下降相关。
Objective To investigate the role of gene methylation in the pathogenesis of lung cancer. Methods Respiratory department, First Affiliated Hospital of Nanjing Medical University, Zhongshan Hospital of Fudan University and Shanghai Cancer Institute from October 2004 to December 2005 using methylation-specific polymerase chain reaction (MSP) and RT -PCR detection of methylation and mRNA transcription level. Results The target sites of partial methylation of lung cancer cell line A549 include p16INK4a, p73, RASSF1a and CDH1. The targets of complete methylation include MGMT, CDH13 and so on. The targets of SH-77 partial methylation include p16INK4a, p73, WT1 and CDH1. The targets of complete methylation include RASSF1a and MGMT. The targets of partial methylation of SPC-A1 include p16INK4a, p73, CDH1, MYOD1 and CDH13. The targets of complete methylation include WT1 and RAR -β. The transcriptional levels of methylation of 5 genes including RASSF1a, WT1, MYOD1, MGMT and RAR-β were all lower than that of non-methylated cell lines or even not transcribed at all. Conclusion CpG islands methylation of tumor suppressor gene often occurs in NSCLC cell lines, and methylation may be related to the decrease of transcription level of tumor suppressor gene.