p53-Bax线粒体凋亡通路DNA甲基化与胆管癌病理生物学的关系  

Role of DNA methylation of p53-Bax mitochondriai apoptosis pathway in cholangiocarcinoma

作　　者：刘小方[1] 孙宪春[1] 于绍平[1] 孔凡民[2] 张翠生[1] 周先亭[1] 

机构地区：[1]青岛大学医学院附属烟台毓璜顶医院肝胆外科,烟台264000 [2]中国医科大学附属第一临床学院普二外科,沈阳100001

出　　处：《中华临床营养杂志》2010年第1期42-47,共6页Chinese Journal of Clinical Nutrition

基　　金：基金项目：山东省自然科学基金（Y2008C82）

摘　　要：目的探讨p53-Bax线粒体凋亡通路抑癌基因启动子区的甲基化状态与胆管癌病理生物学行为的关系。方法采用甲基化PCR检测36例胆管癌患者癌组织和癌旁组织中抑癌基因甲基化诱导静止基因（TMS1／ASC）、死亡相关蛋白激酶（DAPK）和p14启动子区甲基化状态，并对p53基因外显子5～8进行DNA测序，分析以上基因的突变与胆管癌生物学行为的关系。结果24例（66．7％）胆管癌患者癌组织中至少有1个抑癌基因启动子区存在甲基化，p14、DAPK和TMS1／ASC的甲基化率分别为25％、30．6％和36．1％。5例（13．9％）患者的癌旁组织中存在抑癌基因启动子区甲基化，其中TMS1／ASC启动子区甲基化3例（8．3％），DAPK启动子区甲基化2例（5．6％）。DNA测序显示，22例（61．1％）胆管癌患者癌组织中p53基因外显子5～8存在突变。其中14例（38．9％）p53基因外显子突变伴1个以上抑癌基因启动子区甲基化，与胆管癌的病理类型、浸润深度、分化程度显著相关（P〈0．05）。抑癌基因非甲基化及p53突变阴性组（4例）术后1、2、3年的生存率分别为70％、43％、28％，抑癌基因甲基化及p53突变阳性组（14例）术后1、2、3年的生存率分别为28％、5％、0％，前者的生存率显著高于后者（X^2=9．060，P=0．03）。结论p53-Bax线粒体凋亡通路中抑癌基因启动子过甲基化是胆管癌组织中常见的分子事件，癌旁组织中TMS1／ASC和DAPK基因甲基化程度虽然较低，但可能对胆管癌有早期诊断意义。p53突变伴抑癌基因甲基化与胆管癌的病理生物学行为有关，趋向于较高的恶性程度和较低的生存率。Objective To study the methylation status of the promoter region of several tumor suppressor genes in p53-Bax mitochondrial apoptosis pathway and its role in cholangiocarcinoma. Methods The hypermethylation of the promoter region of tumor suppressors death-associated protein kinase （ DAPK）, p14, and target of methylation-associoted silencing-1 （TMS1/ASC） were detected by methylation-specific PCR. p53 gene status （exon 5-8 ） were examined by automated sequencing. The relationship between gene mutations and the biological behaviors of cholangiocarcinoma was analyzed. Results Methylation existed in at least one promoter region of tumor suppressor gene in the tumor tissues of 24 patients （66.7%）. The frequencies of tumor suppressor gene methylation in cholangiocarcinoma were： p14 24% , DAPK 30. 6% , and TMS1/ASC 36. 1%. The frequencies of tumor suppressor gene methylation in the adjacent tissues were： TMS1/ASC 8.3% and DAPK 5.6%. DNA sequencing showed p53 gene mutation was found in 22 of 36 patients （61.1%）, and p53 gene mutation combined with the methylation of tumor suppressor was found in 14 （38.9%） patients, which was significantly correlated with pathologic biology, invasion, and differentiation （P 〈 0.05 ）. The 1-year, 2-year, and 3-year survival rates were significantly higher in tumor-suppressing genes methylation group （n = 4） （70% , 43% , and 28% , respectively） than those in p53 gcne mutation group （n = 14） （28%, 5%, and 0%, respectively） （X^2 = 9.060, P = 0.03）. Conclusions Promoter hypermethylation of p53-Bax mitoehondrial apoptosis pathway is a common epigenetic event in cholangiocarcinoma. Although the methylations of TMSI/ASC and DAPK genes in the adjacent tissues are relatively low, they may be informative for the early detection of cholangiocarcinoma, p53 gene mutation combined with the methylation of tumor suppressor may be related with the pathologic biology of cholangiocarcinoma, making the latter trend to be with high malignancy and poor prog

关 键 词：胆管癌 甲基化聚合酶链反应 p53-Bax线粒体凋亡通路 

分 类 号：R735[医药卫生—肿瘤]