AXIN2基因在肝细胞癌中的表达及甲基化研究

目的 观察肝细胞癌(HCC)中AXIN2 mRNA表达水平,分析AXIN2基因甲基化水平对mRNA表达的影响及在HCC发生、发展中的意义.方法 收集手术切除的53例HCC和配对癌旁组织标本、7例正常肝组织标本和5种人肝癌细胞系.应用荧光定量PCR方法检测AXIN2mRNA水平的表达和AXIN2基因启动子区甲基化状态.结果 AXIN2在癌组织中的mRNA表达水平(0.1629±0.0679)低于癌旁组织(0.4155±0.2330),差异有统计学意义(Z=-2.567,P=0.010).HCC和癌旁组织中AXIN2基因甲基化水平(39.77%±3.89%和36.92%±2.81%)均高于正常肝组织(7.38%±2.40%,t 值分别=-3.663和-4.591,P值分别=0.009和0.007).5种人肝癌细胞系中AXIN2基因均呈高甲基化状态.AXIN2 mRNA表达水平与甲基化程度呈负相关(r=-0.458,P=0.032).TNMⅢ期HCC患者的AXIN2甲基化水平高于TNM Ⅰ和Ⅱ期患者(P=0.008).结论 AXIN2 mRNA表达水平下降与其高甲基化状态相关,AXIN2 mRNA低表达和启动子区异常甲基化可能是HCC发生、发展的重要机制之一.

Abstract：

Objective To investigate AXIN2 mRNA expression level in hepatocellular carcinoma (HCC) , and to analyze the effect of AXIN2 gene methylation status on its mRNA expression and HCC genesis and development. Methods Fifty-three surgical excised HCC specimens and paired adjacent non-cancerous specimens, seven normal liver specimens and five HCC cell lines were collected. The expression of AXIN2 at mRNA level and the methylation status of AXIN2 gene promoter were determined by quantitative PCR. Results The expression of AXIN2 mRNA was lower in HCC tissues (0.1629 + 0.0679) than that in adjacent non-cancerous tissues (0. 4155 + 0. 2330), and there was significant difference (Z= -2. 567, P = 0. 010). The methylation level of AXIN2 gene in HCC and adjacent non-cancerous tissues (39. 77% ±3. 89%, and 36. 92% ±2. 81%) was significantly higher than that in normal liver tissues (7. 38% ±2. 40% , t=-3. 663 ,P = 0. 009;t= -4. 591 ,P = 0. 007).AXIN2 gene was hypermethylated in all five HCC cell lines. There was a negative correlation between AXIN2 mRNA expression level and the degree of methylation ( r = -0. 458, P = 0. 032). The methylation level was higher in TNM Ⅲ patients of HCC than that in TNM Ⅰ and Ⅱ patients (P =0.008). Conclusion The down-regulation of AXIN2 gene mRNA expression is correlated with its hypermethylation status. The low expression of AXIN2 mRNA and the abnormal methylation of promoter may be one of the important mechanism of HCC genesis and development.

The expression and methylation of AXIN2 gene in hepatocellular carcinoma

Objective To investigate AXIN2 mRNA expression level in hepatocellular carcinoma (HCC) , and to analyze the effect of AXIN2 gene methylation status on its mRNA expression and HCC genesis and development. Methods Fifty-three surgical excised HCC specimens and paired adjacent non-cancerous specimens, seven normal liver specimens and five HCC cell lines were collected. The expression of AXIN2 at mRNA level and the methylation status of AXIN2 gene promoter were determined by quantitative PCR. Results The expression of AXIN2 mRNA was lower in HCC tissues (0.1629 + 0.0679) than that in adjacent non-cancerous tissues (0. 4155 + 0. 2330), and there was significant difference (Z= -2. 567, P = 0. 010). The methylation level of AXIN2 gene in HCC and adjacent non-cancerous tissues (39. 77% ±3. 89%, and 36. 92% ±2. 81%) was significantly higher than that in normal liver tissues (7. 38% ±2. 40% , t=-3. 663 ,P = 0. 009;t= -4. 591 ,P = 0. 007).AXIN2 gene was hypermethylated in all five HCC cell lines. There was a negative correlation between AXIN2 mRNA expression level and the degree of methylation ( r = -0. 458, P = 0. 032). The methylation level was higher in TNM Ⅲ patients of HCC than that in TNM Ⅰ and Ⅱ patients (P =0.008). Conclusion The down-regulation of AXIN2 gene mRNA expression is correlated with its hypermethylation status. The low expression of AXIN2 mRNA and the abnormal methylation of promoter may be one of the important mechanism of HCC genesis and development.