卵巢上皮癌中DNA错配修复基因启动子区甲基化状态研究  

Methylation status of promoter of mismatch repair genes hMLH1 and hMSH2 in epithelial ovarian cancer

作　　者：张师前[1] 张爱凤[1] 张琳琳[1] 傅乐乐[1] 于浩[1] 

机构地区：[1]山东大学齐鲁医院妇产科,济南250012

出　　处：《中华检验医学杂志》2007年第6期613-616,共4页Chinese Journal of Laboratory Medicine

基　　金：山东省优秀中青年科研基金(2005BS03013)

摘　　要：目的探讨卵巢上皮癌中 DNA 错配修复基因(hMLH1、hMSH2)启动子区甲基化状态及其在卵巢癌发生发展中的作用。方法用甲基化特异性 PCR(MSP)法检测20份正常卵巢组织,25份良性卵巢肿瘤,56份卵巢上皮癌中 hMLH1、hMSH2基因启动子区的甲基化状态;同时检测5-氮-2′-脱氧胞苷(5-aza-2′-deoxycytidine,5-Aza-CdR)处理前后卵巢癌细胞株 SKOV3和3AO 中 hMLH1、hMSH2甲基化改变;逆转录(RT)-PCR 法检测5-Aza-CdR(1 μm/L)处理前后卵巢癌细胞株中 hMLH1和 hMSH2 mRNA 表达水平。结果正常卵巢癌组织中均未见 hMLH1、hMSH2启动子甲基化;良性卵巢肿瘤中 hMLH1和 hMSH2甲基化阳性率分别为4%(1/25)、8%(2/25);卵巢上皮癌中 hMLH1和hMSH2甲基化阳性率分别为30.4%(17/56)、51.8%(29/56);且与肿瘤细胞的分化程度和淋巴结转移密切相关(P<0.05)。5-Aza-CdR 处理卵巢癌细胞株后,可逆转 hMLH1和 hMSH2启动子区的甲基化,细胞株的 hMLH1和 hMSH2 mRNA 表达均有不同程度的增加。结论 DNA 错配修复基因hMLH1、hMSH2甲基化为卵巢癌发生发展中的早期基因改变,有可能成为卵巢癌早期诊断、评价疗效和判定预后的分子生物学指标。hMLH1和 hMSH2甲基化与 mRNA 表达密切相关,是表达调节的重要方式之一,这种改变可被甲基化酶抑制剂所逆转。Objective To explore the methylation status of hMLH1 and hMSH2 promoter region in the epithelial ovarian cancer and its role in oncogenesis. Methods Methylation status of hMLH1 and hMSH2 promoter region was assayed in 20 normal ovarian tissues, 25 benign epithelial tumor, 56 malignant epithelial tumor and cell lines SKOV3,3AO by methylation-specific PCR（MSP）. SKOV3 and 3AO were analyzed before and after 5-aza-2′-deoxycytidine （5-Aza-CdR） treatment. In addition, an alterations of mRNA expression of hMLH1 and hMSH2 was observed by reverse transcription polymerase chain reaction （PT-PCR）. Results No methylation of hMLH1 and hMSH2 promoter was found in normal ovarian tissues. CPG islands methylation of hMLH1 and hMSH2 was observed in 4% （ 1/25 ）, 8% （ 2/25 ） respectively in benign epithelial tumor, 30.4% （ 17/56 ）, 51.8% （ 29/56 ） respectively in malignant epithelial tumor. Methylation status in promoter showed obvious correlation with pathological grade and lymph node metastasis （P 〈 0. 05 ）. After 5-Aza-CdR （ 1 μm/L） treatment, hMLH1 and hMSH2 methylation was induced or completely reversed, and their mRNA expression was increased differently. Conclusions Methylation of hMLH1 and hMSH2 may be involved in the carcinogenesis of ovarian cancer and may serve as predictive/ prognostic parameter. The close correlation between hMLH1 and hMSH2 methylation of their mRNA suggests that methylation which can be reversed, is an important pathway in the regulation of gene expression. Thus, it provides a new way for therapy of ovarian cancer.

关 键 词：卵巢肿瘤 DNA甲基化 错配修复基因 

分 类 号：R737.31[医药卫生—肿瘤]