EYA4基因在结直肠癌中的甲基化状态及其意义

Methylation of EYA4 Gene and Significance in Colorectal Cancer

背景：EYA4（eyes absent4）是一种非巯基蛋白酪氨酸磷酸酶，参与器官发育、细胞凋亡调控、先天性免疫、DNA损伤修复、血管生成等过程。目的：研究EYA4基因在结直肠癌中的甲基化状态及其意义。方法：选取2006年6月～2007年1月上海交通大学医学院附属仁济医院31例结直肠癌患者，采集其癌组织和相应癌旁非癌组织。以5-氮杂-2’-脱氧胞苷（5-Aza—dC）处理人结肠癌细胞株HT29、HCT116、SW480、SW1116。应用MSP技术检测结直肠癌组织、癌旁非癌组织、HT29、HCT116、SW480、SW1116细胞中EYA4基因启动子的甲基化状态。分析结直肠癌患者临床病理特征与EYA4基因甲基化关系。采用RT—PCR和蛋白质印迹法分别检测结肠癌细胞株中EYA4基因和蛋白的表达水平。结果：结直肠癌组织EYA4基因启动子甲基化率显著高于癌旁组织（77．4％对6．5％，P〈0．01）。EYA4基因和蛋白在启动子甲基化的HT29、HCT116、SW480细胞中不表达，在启动子非甲基化的SW1116细胞中显著表达。以5-Aza—dC处理后EYA4基因和蛋白在LIT29和SW480细胞中表达上调。结论：EYA4基因是结直肠癌发生的甲基化相关基因，有望成为结直肠癌的诊断标记物。

Background： Eyes absent 4 （EYA4） is a non-thiol protein tyrosine phosphatase, and is involved in organ development, ceil apoptosis regulation, innate immunity, DNA damage repair and angiogenesis. Aims： To study the metbylation of EYA4 gene and its significance in colorectal cancer. Methods ： A total of 31 patients with eolorectal cancer from June 2006 to January 2007 at Renji Hospital, Shanghai Jiaotong University School of Medicine were enrolled. Coloreetai cancer tissue and paraeaneerous tissue specimens were collected. Human colonic cancer cell lines HT29, HCT116, SW480 and SWl116 were treated with 5-aza-2＇ -deoxycytidine （5-Aza-dC）. MSP technique was used to detect methylation status of EYA4 gene promotor in tumor tissue, paracancerous tissue, HT29, HCT116, SW480 and SWl116 cells. The correlation between elinicopathologic features and the methylation status of EYA4 gene were analyzed. RT-PCR and Western blotting were used to detect the expressions of EYA4 gene and protein, respectively. Results ： The metbylation rate of EYA4 gene promotor was significantly higher in tumor tissue than that in paracancerous tissue （77.4% vs. 6.5% , P 〈 0.01 ）. The expressions of EYA4 gene and protein were in silence in HT29, HCT116 and SW480 cells with methylated promotor, while expressions of EYA4 gene and protein were detected in SWl116 cells with demethylated promotor. Treated with 5-Aza-dC upreguiated the expressions of EYA4 gene and protein in HT29 and SW480 cells. Conclusions ： EYA4 gene is the methylation-related gene in colorectal cancer. It may become a diagnostic marker for eolorectal cancer.