结晶型硫化镍及反式-BPDE恶性转化16HBE细胞hMSH2基因甲基化的研究  

Aberrant methylation of the hMSH2 gene in the Nis and anti-BPDE-transformed 16 HBE cells

作　　者：刘莉莉[1] 陈家堃[2] 黄建勋[1] 吴中亮[2] 宋向荣[1] 

机构地区：[1]广东省职业病防治院毒理科,广东广州510300 [2]广州医学院化学致癌研究所

出　　处：《毒理学杂志》2008年第6期416-420,共5页Journal of Toxicology

基　　金：国家自然科学基金资助项目(39170651)

摘　　要：目的对结晶型硫化镍(NiS)和反式二氢二醇环氧苯并芘(anti-7,8,-dihydrodiol-9,10-epoxide benzo(a)pyrene,BPDE)恶性转化及接种裸鼠成瘤的人支气管上皮细胞(16HBE)hMSH2基因启动子甲基化状况进行研究,探讨镍及反式-BPDE的表遗传致癌机制。方法采用甲基化特异性PCR(MSP)法、荧光定量PCR法和蛋白免疫印迹法检测结晶型NiS和反式-BPDE恶性转化及成瘤的16HBE细胞hMSH2基因启动子甲基化状况及其mRNA和蛋白表达,并用去甲基化因子5-Azac(5-Aza-2-′deoxycytidine)处理有异常甲基化的细胞。结果结晶型NiS和反式-BPDE恶性转化及成瘤的16HBE细胞hMSH2基因启动子区存在CpG岛的高甲基化;与非转化16HBE细胞比较,转化及成瘤的16HBE细胞hMSH2基因mRNA和蛋白表达下降;有异常甲基化的细胞经去甲基化处理后甲基化消失。结论结晶型NiS和反式-BPDE恶性转化及成瘤的16HBE细胞hMSH2基因启动子区CpG岛的高甲基化使其mRNA表达下降,并可能导致hMSH2基因表达抑制,这可能是结晶型NiS及反式-BPDE诱导16HBE细胞转化和成瘤的一种表遗传致癌机制。甲基化的可逆性对今后研究其表型逆转以及药物治疗提供了重要线索。Objective To study aberrant methylation of the hMSH2 gene promoter in the Nis and anti-BPDE transformed 16 HBE cells and explore the possible epigenctic mechanism for Nis and anti-BPDE Carcinogenesis. Methods DNA methylation patterns in the hMSH2 gene promoter were determined by methylation-specifie PCR assay, the mRNA expression levels of hMSH2 gene were analysed by Fluorescent quantitative-PCR, and the protein expression levels were analyzed by Western blot assay. The result was compared with non-transformed 16 HBE cells and the aberrant methylation cells were treated with demethylating agent 5-Aza-2＇- deoxycytidine. Results Hypermethylation in CpG island of the hMSH2 gene promoter was indentified in the Nis and anti-BPDE transformed 16 HBE cells; comparing with non-transformed cells, hMSH2 gene mRNA and protein expression levels of the Nis and anti- BPDE transformed 16 HBE cells were reduced and hypermethylation of the hMSH2 disappeared. Conclusion Hypermethylation in CpG island of the hMSH2 gene promoter is known to result in mRNA expression reducing and gene silencing probably, it may represent a possible epigenetic mechanism for Nis and anfi-BPDE-indueed cells transformation and carcinogenesis. Reversible methylation offered an important evidence for phenotype inversion and drug treatment.

关 键 词：HMSH2 甲基化 硫化镍 反式-BPDE 

分 类 号：R994.3[医药卫生—毒理学]