脑胶质瘤中SLC5A8和TMS1/ASC基因启动子区甲基化及mRNA表达的研究  

The methylation and mRNA expression of SLC5A8 and TMS1/ASC genes in human glioma

作　　者：姜政[1] 李新钢[2] 胡锦[3] 卢大儒[4] 周伟[5] 江玉泉[2] 栗超越[6] 

机构地区：[1]山东大学齐鲁医院神经外科实验室,济南250012 [2]山东大学齐鲁医院 神经外科,济南250012 [3]上海交通大学第六人民医院神经外科 [4]复旦大学生命科学院遗传学研究所遗传工程国家重点实验室 [5]山东省肿瘤防治研究院放疗科 [6]河南省人民医院神经外科

出　　处：《中华医学杂志》2007年第5期292-297,共6页National Medical Journal of China

基　　金：国家自然科学基金(30371459);山东省卫生系统杰出学科带头人资助项目

摘　　要：目的研究肿瘤抑制基因SLC5A8和 TMS1/ASC 在胶质瘤中的启动子区甲基化和mRNA 表达情况,探讨其与临床情况之间的关系。方法通过甲基化聚合酶链反应(MSP)检测SLC5A8和 TMS1/ASC 基因在88例胶质瘤组织、10例正常脑组织及胶质瘤细胞株 U251和 SHG-44中的 DNA 甲基化情况;通过传统逆转录聚合酶链反应(RT-PCR)和实时定量 PCR 检测 SLC5A8和TMS1/ASC 的 mRNA 表达情况;检测去甲基化试剂5-氮杂脱氧胞苷(5-Aza-CdR)作用于细胞株后,对基因 DNA 甲基化和 mRNA 表达的影响。结果在88例胶质瘤中,SLC5A8启动子区的甲基化发生率为70.45%(62/88),其甲基化率随胶质瘤恶性程度的增加而增高;TMS1/ASC 启动子区的甲基化发生率为51/88(57.95%),其甲基化率随胶质瘤恶性程度的增加而降低。10例正常脑组织中均未检测到 SLC5A8和 TMS1/ASC 基因的甲基化。在各级别胶质瘤中 SLC5A8和 TMS1/ASC 的 mRNA 与正常脑组织相比均表达下凋,差异均有统计学意义(均 P<0.05)。在 U251和 SHG-44胶质瘤细胞株中均检测到 SLC5A8和 TMS1/ASC 基因的甲基化,去甲基化试剂5-Aza-CdR 均能重新激活 SLC5A8和TMS1/ASC 基因的表达。结论 SLC5A8和 TMS1/ASC 基因在胶质瘤中的启动子区甲基化导致其mRNA 表达下调,其甲基化的发生率及 mRNA 表达与胶质瘤的恶性程度密切相关。Objective To study the methylation status of the SLCSA8 and TMS1/ASC genes, candidate tumor-inhibiting genes closely related to the central nervous system, in the promoter regions , the mRNA expression of these 2 genes, and their correlation with the clinical characteristics in human glioma. Methods The methylation status of SLCSA8 and TMS1/ASC genes in the promoter regions was studied by methylation specific PCR （MSP） in the specimens of primary astrocytuma from 88 patients, 55 males and 33 females, aged 12-81, and 10 specimens of normal brain tissue, all obtained during operation, and in the human glioma cells of the lines U251 and SHG-44. The mBNA expression levels of SLCSA8 and TMS1/ASC genes in 30 specimens of primary glioma and 10 specimens of normal brain tissue were determined by conventional RT-PCR and real-time PCR. 5-Aza-2＇-deoxycytidine （5-Aza-CdR）, a demethylating agent, was added into the culture fluid of the U251 and SHG-44 cells, and then real-time PCR was used to the methylation status and mRNA expression levels of the SLC5A8 and TMS1/ASC genes. Results MSP showed that the SLC5A8 promoter region was hypermethylated in 62 of the 88 specimens of astrocytoma （70.45%） and the TMS1/ASC promoter region was hypermethylated in 51 of the88 specimens of astrocytoma （57.95%）. But no methylation of SLCSA8 and TMS1/ASC promoter was detected in the 10 specimens of normal brain tissue. The mRNA expression of SLC5A8 gene and the mRNA expression of TMS1/ASC gene in the specimens of astrocytoma of different pathological grades were all significantly decreased compared to the specimens of normal brain tissue （ all P 〈 0.05 ）. The mRNA expression of SLC5A8 gene was not significantly related to the age and sex, however, the mRNA expression of TMS1/ASC was significantly higher in the age group 〉 60 than in other age groups （ all P 〈 0. 05 ）. Both U251 and SHG-44 glioma cells showed methylation of SLC5A8 and TMS1/ASC genes and after the treatment of 5-Aza- CdR both genes showed reactivat

关 键 词：神经胶质瘤 基因 抑制 肿瘤 DNA甲基化 

分 类 号：R739.41[医药卫生—肿瘤]