骨肉瘤中WIF-1甲基化及WIF-1、β-catenin蛋白表达的研究

Methylation of WIF-1 gene and expression of WIF-1 protein, β-catenin protein in human osteosarcoma

目的检测骨肉瘤中WIF-1基因启动子区甲基化状态及WIF-1蛋白、β-catenin蛋白表达情况,探讨它们之间的相关性及其与骨肉瘤发生发展的关系,为骨肉瘤的分子靶向治疗提供理论依据。方法收集青岛大学2008年1月至2013年6月骨肉瘤组织50例,并取骨软骨瘤组织30例作为对照,应用甲基化PCR和免疫组化两种方法,检测骨肉瘤组及对照组WIF-1基因启动子区甲基化状态及WIF-1蛋白、β-catenin蛋白表达情况。结果骨肉瘤和骨软骨瘤组织的WIF-1启动子甲基化阳性率分别为70.0%和20.0%,差异具有统计学意义(P<0.01)。WIF-1启动子甲基化阳性率随着骨肉瘤分期的增加而升高。骨肉瘤和骨软骨瘤组织中WIF-1蛋白表达率分别为42.0%和70.0%,两者之间差异有统计学意义(P<0.05),且WIF-1启动子甲基化阳性与WIF-1蛋白表达呈明显负相关(P<0.05)。骨肉瘤和骨软骨瘤组织中β-catenin蛋白表达率分别为70.0%和43.3%,两者之间差异有统计学意义(P<0.05),WIF-1启动子甲基化与β-catenin蛋白表达呈正相关(P<0.05)。结论 WIF-1基因甲基化状态可能抑制了WIF-1蛋白的表达,从而引起β-catenin蛋白在在胞质中异常积聚表达,从而使经典Wnt信号转导通路过度激活,参与细胞的生长、增殖,导致骨肉瘤的发生发展。

Objective This research aims to investigate the promoter methylation status of WIF-1 gene and the expression of WIF-1 protein, β-catenin protein in human osteosarcoma, and to explore their relations with clinical and pathological parameters. In order to provide the theory support for molecular targeting therapy of osteosarcoma and prognosis improvement. Methods 50 tissues of osteosarcoma and 30 tissues of chondroma as the control group had been collected from Qingdao University affiliated Hospital from 2008 to 2013. Methylation specific PCR (MSP) was used to test the promoter methylation of WIF-1 gene in osteosarcoma and chondroma, besides immunohistochemical SP method was employed to investigate the expression of WIF-1 protein, β-catenin protein in human osteosarcoma and chondroma. SPSS 21.0 was utilized for statistical analysis. Results The positive rate of promoter methylation of WIF-1 gene in osteosarcoma tissues and chondroma tissues were 70.0% and 20.0%, respectively, and the difference was statistically significant (P<0.01). The rate significantly increased with tumor stage. The rate of positive expression of WIF-1 protein in osteosarcoma and chondroma were 42.0% and 70.0% respectively, and the difference was statistically significant (P<0.05). What’s more, the positive rate of promoter methylation of WIF-1 gene was negatively correlated with the expression of WIF-1 protein (P<0.05). The positive expression of β-catenin protein in osteosarcoma and chondroma were 70.0% and 43.3% respectively, and the difference was statistically significant (P<0.05). Also the methylation of WIF-1 gene was positively correlated with the expression of β-catenin protein&nbsp;(P<0.05). Conclusion The methylation status of WIF-1 gene may inhibit the expression of WIF-1 protein, which causes abnormal accumulation of expression of β-catenin proteins in cytoplasm. Therefore, the classic Wnt signaling pathways is activated excessively. They involve in cell growth and proliferation and lead to the growth of osteosarcoma.