摘要
目的研究分泌型卷曲相关蛋白（SFRP）基因启动子区CpG岛甲基化与结直肠癌的关系。方法采用甲基化特异性PcR（MsP）技术检测20对结直肠癌及相应癌旁组织中SFRP基因启动子区CpG岛甲基化状况，T—A克隆测序验证MSP产物。5氮杂-2＇-脱氧胞苷对结直肠癌细胞株HCT116、SW480进行去甲基化处理，MSP和Western印迹法分别检测细胞株中SFRP基因甲基化和蛋白表达。结果SFRP1、2、4、5在结直肠癌中甲基化率分别为19／20、17／20、3／20、13／20，癌旁组织中分别为12／20、8／12、1／20、7／20。结直肠癌中SFRP1、2、5甲基化率均高于癌旁组织，差异有统计学意义（P〈0．05）。HCT116细胞株SFRP1、2、4、5基因均发生甲基化，而SW480细胞株中仅SFRPI和SFRP2出现启动子甲基化。SFRP蛋白表达与启动子甲基化呈明显负相关，经5-氮杂-2＇-脱氧胞苷处理后能有效恢复SFRP蛋白表达。结论SFRP1、2、5甲基化可能与结直肠癌的发生有关，SFRP基因甲基化与其表达失活密切相关。
Objective To investigate the association of promoter hypermetbylation of secreted frizzled-related proteins （SFRPs） in patients with colorectal cancer. Methods The promoter hypermethylation of SFRPs in 20 sporadic colorectal cancer tissues and adjacent mucosa were detected by methylation-specific PCR. The amplified DNA was subcloned into the T-A cloning vector and sequenced. Two colorectal cancer cell lines （HCT116 and SW480） were treated with 5-aza-2＇ deoxycytidine for demethylation. The promoter hypermethylation and protein expression of SFRPs in colorectal cancer cell lines were detected by methylation-specific PCR and Western blotting. Results It was demonstrated that the hypermethylation of SFRP 1, 2, 4 or 5 was 19/20,17/20,3/20 or 13/20 in cancer tissues, respectively, whereas it was 12/20, 8/12, 1/20 or 7/20 in adjacent mucosa, respectively. SFRP 1, 2 or 5 methylation was more frequently found in cancer tissue than in adjacent mucosa （P〈0.05）. Methylation of SFRP 1, 2, 4 and 5 were found in HCT116 cell line, but only SFRP1 and SFRP2 were found in SW480 cell line. There was a negative correlation between protein expression and methylation of SFRPs. The Western blotting revealed that SFRP protein reexpressed after it treated with 5-aza-2＇ deoxycytidine. Conclusion Methylation of SFRP 1, 2 or 5 gene is associated with the evolution of colorectal cancer, and is closely related to silencing expression.
出处
《中华消化杂志》
CAS
CSCD
北大核心
2009年第7期451-454,共4页
Chinese Journal of Digestion
基金
上海市科学技术发展基金资助项目（064119512,08DZ2293102）
关键词
结直肠肿瘤
分泌型卷曲相关蛋白
甲基化
Colorectal neoplasms
Methylation
Secreted frizzled-related protein genes
