Regulation of demethylation and re-expression of RASSF1A gene in gastric cancer cell lines by combined treatment of 5-Aza-CdR and NaB  

作　　者：Wen-Jing Shen Dong-Qiu Dai Yue Teng Hong-Bo Liu 

机构地区：[1]Department of Surgical Oncology, The First Alliliated Hospital, China MedicalUniversity, Shenyang 110001, Liaoning Province, China [2]Department of Health Statistics, China MedicalUniversity, Shenyang 110001, Liaoning Province, China

出　　处：《World Journal of Gastroenterology》2008年第4期595-600,共6页世界胃肠病学杂志（英文版）

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

摘　　要：AIM： To investigate the changes of methylation state and expression of RASSF1A gene in human gastric cancer cell lines SGC7901 and BGC823 which were treated in vitro with demethlylating agent 5-Aza-CdR in combination with histone deacetylase inhibitor NaB. METHODS： After SGC7901 and BGC823 cells were treated with 5-Aza-CdR and/or NaB, the methylation state of RASSFIA gene was detected by methylationspecific PCR, and the changes in expression of mRNA and protein level of RASSFIA gene were observed by RT-PCR and Western-blotting before and after drug treatment. RESULTS： Hypermethylation was detected in the promoter region of RASSF1A gene in both SGC7901 and BGC823 cells, and there was no expression of this gene at both mRNA and protein level. After treatment with 5-Aza-CdR, demethylation occurred in the promoter region of RASSFIA gene, which subsequently induced re-expression of this gene. The treatment with NaB alone showed no effect on the methylation state and expression of RASSFIA gene. The combined treatment of 5-Aza-CdR and NaB induced complete demethylation of RASSFIA gene, leading to a significantly higher reexpression of the mRNA and protein of RASSFIA than those treated with 5-Aza-CdR alone （P 〈 0.05）. CONCLUSION： Hypermethylation in the promoter region is related to inactivation of RASSFIA gene in human gastric cancer cell lines SGC7901 and BGC823, while demethlylating agent 5-Aza-CdR can reverse the methylation state of RASSF1A gene and induce itsre-expression. Histone deacetylase inhibitor NaB had a synergistic effect with 5-Aza-CdR in both demethylation and gene transcriptional regulation.AIM: To investigate the changes of methylation state and expression of RASSF1A gene in human gastric cancer cell lines SGC7901 and BGC823 which were treated in vitro with demethlylating agent 5-Aza-CdR in combination with histone deacetylase inhibitor NaB. METHODS: After SGC7901 and BGC823 cells were treated with 5-Aza-CdR and/or NaB,the methylation state of RASSF1A gene was detected by methylation-specific PCR,and the changes in expression of mRNA and protein level of RASSF1A gene were observed by RT-PCR and Western-blotting before and after drug treatment. RESULTS: Hypermethylation was detected in the promoter region of RASSF1A gene in both SGC7901 and BGC823 cells,and there was no expression of this gene at both mRNA and protein level. After treatment with 5-Aza-CdR,demethylation occurred in the promoter region of RASSF1A gene,which subsequently induced re-expression of this gene. The treatment with NaB alone showed no effect on the methylation state and expression of RASSF1A gene. The combined treatment of 5-Aza-CdR and NaB induced complete demethylation of RASSF1A gene,leading to a significantly higher re-expression of the mRNA and protein of RASSF1A than those treated with 5-Aza-CdR alone (P < 0.05). CONCLUSION: Hypermethylation in the promoter region is related to inactivation of RASSF1A gene in human gastric cancer cell lines SGC7901 and BGC823,while demethlylating agent 5-Aza-CdR can reverse the methylation state of RASSF1A gene and induce its re-expression. Histone deacetylase inhibitor NaB had a synergistic effect with 5-Aza-CdR in both demethylation and gene transcriptional regulation.

关 键 词：5-AZA-CDR NAB RASSFIA gene Gastric cancer DNA methylation 

分 类 号：R735.2[医药卫生—肿瘤]