Metastatic suppressor genes inactivated by aberrant methylation in gastric cancer

作     者：Jian-Feng Wang Dong-Qiu Dai 

作者机构：Department of Surgical Oncology the FirstAffiliated Hospital China Medical University Dalian UniversityAffiliated Xinhua Hospital Shenyang 110001 Liaoning ProvinceChina Department of Surgical Oncology the FirstAffiliated Hospital China Medical University Shenyang 110001Liaoning Province China 

出 版 物：《World Journal of Gastroenterology》 (世界胃肠病学杂志（英文版）)

年 卷 期：2007年第13卷第43期

页      面：5692-5698页

核心收录：

学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学] 

基　　金：the National Natural Science Foundation of China, No.30271477 and No.30572162 the Special Scientific Research Foundation for Doctors, State Education Ministry, No.20050159001 

主　　题：Gastric cancer Methylated CpG islandsamplification Representational difference analysis DNA methylation gene PTPRG 

摘      要：AIM: To screen out the differentially methylated DNA sequences between gastric primary tumor and metastatic lymph nodes, test the methylation difference of gene PTPRG between primary gastric tumor and metastatic lymph nodes, and test the regulatory function of 5-aza- 2-deoxycytidine which is an agent with suppression on methylation and the level of methylation in gastric cancer cell line. METHODS: Methylated DNA sequences in genome were enriched with methylated CpG islands amplification (MCA) to undergo representational difference analysis (RDA), with MCA production of metastatic lymph nodes as tester and that of primary tumor as driver. The obtained differentially methylated fragments were cloned and sequenced to acquire the base sequence, which was analyzed with bioinformatics. With methylation-specific PCR (MSP) and RT-PCR, methylation difference of gene PTPRG was detected between primary tumor and metastatic lymph nodes in 36 cases of gastric cancer. Methylation of gene PTPRG and its regulated expression were observed in gastric cancer cell line before and after being treated with methylation-suppressive agent. RESULTS: Nineteen differentially methylated sequences were obtained and located at 5 end, exons, introns and 3 end, in which KL59 was observed to be located at 9p21 as the first exon of gene p16 and KL22 to be located at promoter region of PRPRG . KL22, as the probes, was hybridized with driver, tester and 3-round RDA products respectively with all positive signals except with the driver. Significant difference was observed in both methylation rate of gene PTPRG and PTPRG mRNA expression rate between primary tumor and metastatic lymph nodes. Demethylation of gene PTPRG, with recovered expression of PTPRG mRNA, was observed after gastric cancer cell line being treated with methylation-suppressive agent. CONCLUSION: Difference exists in DNA methylation between primary tumor and metastatic lymph nodes of gastric cancer, with MCA-RDA as one of the good anal