胃癌中TIMP3基因的甲基化与表达间的相关性分析  

Correlative Analysis between TIMP3 Gene Methylation And Expression In Human Gastric Cancers

作　　者：杨杨[1] 赵正东[2] 陈楠楠[1] 李岩[1] 张开立[1] 孔庆友[1] 孙媛[1] 吴茉莉[1] 刘佳[1] 李宏[1] 

机构地区：[1]大连医科大学辽宁省癌症基因组重点实验室,辽宁大连116000 [2]大连医科大学第二附属医院,辽宁大连116044

出　　处：《临床军医杂志》2009年第5期878-881,共4页Clinical Journal of Medical Officers

基　　金：国家自然科学基金(30527002;30670946和30700365);辽宁省重点实验室(20060193);创新团队(20077017)科研项目资助

摘　　要：目的探讨转移抑制基因TIMP3(金属组织蛋白酶抑制因子-3)在胃癌和胃癌细胞系中启动子甲基化及其蛋白和mRNA表达的特点,并分析两者之间的关联。方法应用MSP法检测TIMP3基因启动子区的甲基化状态;RT-PCR和免疫组织/细胞化学法检测TIMP3基因mRNA和蛋白的表达;观察DNA去甲基化剂(5-aza-2’-deoxycitydine)对人胃癌细胞系(MGC803和HGC-27)细胞系TIMP3基因表达的影响。结果TIMP3基因于胃癌组织中的甲基化频率为17/33(51.5%);四个胃癌细胞系均存在TIMP3基因的甲基化,而MGC803、BGC823和HGC-27仍有该基因的表达或低水平表达;在去甲基化剂的作用下TIMP3基因的表达水平明显上调。结论TIMP3的异常甲基化是其表达下调或沉默的主要原因并存在部分甲基化的倾向。该指标可作为胃癌的敏感性表观遗传学标记物在胃癌的筛查和诊断中应用。Objective To investigate the correlation between promoter DNA methylation and expression of TIMP3 gene in gastric cancers/GCs in vivo and in vitro,and to analyze the frequencies of TIMP3 methylation in different histological subtypes of gastric cancers. Methods TIMP3 methylation status in GC tissues/cell lines and their premalignant and noncancerous counterparts was checked by methylation specific PCR and its relevance with gene expressions in those samples was analyzed by RT-PCR and immunohistochemical/immunocytochemical staining. DNA methyltransferase inhibitor 5-aza-2’-detoxycytidine （5-aza-dC） was used to erase DNA methylation in MGC803 and HGC-27 GC cell lines and its effect on gene expression was examined.Results High TIMP3 methylation frequency was found at the early stage of gastrocarcinogenesis,which in some cases was not sufficient to block gene expression. Demethylation agent 5-aza-dC successfully enhanced TIMP3 expression in two GC cell lines with TIMP3 methylation. Conclusion Aberrant methylation is the main mechanism of TIMP3 gene down-regulation and silencing in GC tissues and cell lines. The presence of gene expression in TIMP3 methylated cases suggests a possible incomplete methylation. Because of the anti-metastatic role of TIMP3,this gene can be regarded as a sensitive and unfavorable epigenetic marker of GCs.

关 键 词：胃肿瘤 TIMP3基因 甲基化 基因表达 表观遗传学 

分 类 号：R735.2[医药卫生—肿瘤]