中文摘要：

目的研究表明神经胶质瘤中存在Wnt信号通路的异常活化。本研究探讨神经胶质瘤中Wnt信号通路抑制基因启动子区甲基化的改变以及去甲基化药物对其影响。方法对53例恶性胶质瘤组织样本和人胶质瘤细胞系U251、A172检测5个Wnt通路胞外抑制基因：SFRP1、SFRP2、SRFP5、DKK1和WIF1启动子区甲基化状况。去甲基化药物处理胶质瘤细胞后,检测上述5个基因表达水平;采用MTT法和软琼脂细胞集落实验检测胶质瘤细胞生长行为。结果神经胶质瘤组织和细胞系中上述五个基因启动子区存在明显高甲基化修饰。去甲基化药物处理胶质瘤细胞后,RT-PCR分析显示SFRP1、SFRP2、SFRP5和WIF1的表达明显增加,DKK1表达无明显变化;Wnt/β-catenin靶基因CCND1表达明显降低（P〈0.05）;靶基因LRP6表达显著增加（P〈0.01）。MTT实验和软琼脂细胞集落实验显示去甲基化药物可明显抑制胶质瘤细胞增殖。结论在胶质瘤中Wnt信号通路胞外抑制基因的表达受甲基化调控,去甲基化药物可通过逆转基因的甲基化抑制神经胶质瘤细胞增殖,这为将来去甲基化药物用于恶性胶质瘤治疗提供研究依据。

英文摘要：

Objective Abnormal activation of Wnt signaling involves in carcinogenesis and progression of various tumors.Studies have showed that the Wnt signaling was also correlated with gliomas.The purpose of this study is to analyzes the promoter methylation of inhibitor genes of the Wnt pathway and the role of these genes in malignant gliomas.Methods 53 Frozen primary glioma tissues,normal brain tissues and two glioma cell lines A172 and U251 were used for MSP analysis to detect the gene promoter methylation of Wnt pathway inhibitors：SFRP1,SFRP2,SFRP5,DKK1 and WIF1.For checking the role of the promoter methylation in gene expression,cell lines were treated with demethylation drugs to detect the five genes expression and the proliferation of the cells.Results There is at least one of the five genes being hypermethylated in 43 of 53（83%）glioma tissues.The frequency of promoter hypermethylation of SFRP1,SFRP2,SFRP5,DKK1 and WIF1 is 43.40%,28.30%,26.42%,66.04% and 13.21%,respectively.RT-PCR analysis showed that the expression of SFRP1,SFRP2,SFRP5 and WIF1 was significantly increased after the cells were treated with the demethylation drugs;but there was no statistical significance in the expression of DKK1.CCND1 expression,a well known Wnt/β-catenin downstream target gene,was significantly lower compared to the control group（P0.05）;and the expression of LRP6 significantly increased（P0.01）.MTT assay and Soft-Agar assay showed that the proliferation and colony formation ability was suppressed after treatment of both A172（P0.05）and U251（P0.01）with demethylation drugs.Conclusions The hypermethylation of the Wnt pathway inhibitor genes is important in glioma carcinogenesis.The demethylation drug restores the expression of the hypermethylated genes and inhibits the proliferation of the glioma cells.This suggests that the drugs may be used to treat gliomas in the future.