结直肠癌中miR-200家族启动子甲基化状态分析

Status of miR-200 family promoter methylation in colorectal carcinoma

目的检测HCT116、HT29、LS174t、SW480、SW620和LoVo细胞中miR-200家族启动子甲基化状态,分析其与结直肠癌临床分期、分化程度及预后的相关性;同时进行miR-200家族甲基化程度与患者生存相关性分析。方法重亚硫酸盐测序法(bisulfite genomic sequence PCR,BSP)检测6株不同恶性程度的结直肠癌细胞株中miR-200家族启动子甲基化程度;分析其甲基化程度与细胞恶性程度、miR-200a表达量的相关性。甲基化特异性(methylationspecific PCR,MSP)技术检测138例结直肠癌组织中miR-200家族启动子甲基化程度。结果 6株不同恶性程度的结直肠癌细胞株中miR-200家族启动子甲基化程度不同,且其甲基化程度与细胞恶性程度成反比,与细胞株中miR-200a表达量的检测结果一致。结直肠癌组织中miR-200家族启动子甲基化程度与患者年龄无关,与患者性别、肿瘤最大径、淋巴结转移及远处转移、患者术后生存时间相关。结论 miR-200家族的表达受甲基化修饰的调控,且该调控成为影响表达量的主要原因。miR-200家族甲基化程度与结直肠癌患者生存期密切相关,可作为预后指标。

Purpose To detect the promoter methylation status of miR-200 family in HCT116, HT29, LS174t, SW480 and SW620 strains of LoVo cells, and to analyze its correlation with clinical stage, differentiation degree and the prognosis. Methods Bisulfite genomic sequence PCR was used to detect the miR-200 family promoter methylation level in six colorectal cancer cell lines with differ- ent malignant degree. Analysis of the correlation of methylation levels with eel1 malignant degree of the cell lines and miR-200-a ex- pression was conducted. Methylation specific PCR （MSP） was used to detect the miR-200 family promoter methylation in 138 cases of eolorectal cancer tissue. Results Methylation level of miR-200 family promoter was different in six colorectal cancer cell lines with different malignant degree, and the degree of methylation was inversely proportional to the degree of malignant cells, but consistant with the amount of miR-200-a expression. The methylation level of miR-200 family promoters was not correlated with patient age, but corre- lated with the patient gender, tumor size, lymph node and distant metastasis and postoperative survival time in 138 cases of colorectal cancer. Conclusion Expression of miR-200 family is regulated by methylation modification, which is the main cause of the expression level. The methylation degree of the miR-200 family is closely related to the survival in patients with eolorectal cancer, which can be used as a prognostic indicator.