hMLH1基因对脑胶质瘤替莫唑胺耐药的影响及机制研究

Effect of hMLH1 Gene on Temozolomide Resistance in Glioma and its Mechanism

目的:观察h MLH1基因对脑胶质瘤替莫唑胺耐药的影响并探讨其机制。方法:检测脑胶质瘤患者组织、耐药细胞株(U251/TMZ)和亲本敏感细胞株(U251)的h MLH1表达水平;使用5氮杂-2'-脱氧胞苷(5-Aza-CdR)予耐药细胞株去甲基化干预后,采用MBP法检测其h MLH1基因启动子甲基化水平;检测干预前后耐药细胞株的h MLH1表达水平以及替莫唑胺IC50的变化。结果:脑胶质瘤复发患者组织h MLH1表达水平低于初治患者;耐药细胞株h MLH1表达水平低于敏感细胞株,去甲基化干预后耐药细胞株h MLH1表达水平及对替莫唑胺敏感性增加。结论:h MLH1沉默促进脑胶质瘤替莫唑胺耐药,其机制可能与该基因启动子甲基化增强有关。

Objective:To investigate the effect of human mutl homolog 1(hMLH1)on the resistance of temozolomide in glioma cells and its mechanism.Methods:The expressions of hMLH1 in glioma patients,drug-resistant glioma cell line(U251/TMZ)and its parental sensitive cell line(U251)were detected.5-Aza-CdR(5-Aza-CdR)was used to treat the demethylation of drug-resistant cell line.The methylation level of hMLH1 promoter was detected by MBP assay.Further,the expression of hMLH1 and the change of temozolomide IC50 were measured before and after the intervention.Results:The expression level of hMLH1 in patient with recurrent glioma was lower than that in untreated patient;the expression level of hMLH1 in U251/TMZ drug-resistance cell line was lower than that in drug-sensitive group.The expression level of hMLH1 and the sensitivity to temozolomide were increased in the prognosis of demethylation.Conclusion:Gene silence of hMLH1 promotes the drug resistance to temozolomide in glioma cells,which may be related to the increased methylation of hMLH1 gene promoter.