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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 investigate the methylation status of promoter region of DNA mismatch repair gene (hMLH1, hMSH2) in ovarian epithelial carcinoma and its role in the development of ovarian cancer. Methods The methylation status of hMLH1 and hMSH2 gene promoter in 20 normal ovarian tissues, 25 benign ovarian tumors and 56 epithelial ovarian cancer specimens were detected by methylation-specific PCR (MSP) The methylation changes of hMLH1 and hMSH2 in ovarian cancer cell lines SKOV3 and 3AO before and after 5-aza-2’-deoxycytidine (5-Aza-CdR) treatment were detected by reverse transcriptase-polymerase chain reaction -Aza-CdR (1 μm / L) treatment of ovarian cancer cell lines hMLH1 and hMSH2 mRNA expression levels. Results No methylation of hMLH1 and hMSH2 promoter was detected in normal ovarian cancer tissues. The positive rates of hMLH1 and hMSH2 methylation in benign ovarian tumors were 4% (1/25) and 8% (2/25), respectively. The positive rates of ovarian epithelial The positive rates of hMLH1 and hMSH2 methylation in cancer were 30.4% (17/56) and 51.8% (29/56), respectively. The positive rates of hMLH1 and hMSH2 were closely related to the differentiation degree and lymph node metastasis (P <0.05). 5-Aza-CdR treatment of ovarian cancer cell lines can reverse the hMLH1 and hMSH2 promoter methylation, hMLH1 and hMSH2 mRNA expression in cell lines were increased to varying degrees. Conclusion Methylation of DNA mismatch repair genes hMLH1 and hMSH2 may be the early gene mutation in the development and progression of ovarian cancer. It may become a molecular biological indicator for early diagnosis, evaluation of curative effect and prognosis of ovarian cancer. Methylation of hMLH1 and hMSH2 is closely related to mRNA expression, which is one of the important ways of regulating expression. This change can be reversed by methylase inhibitors.