肺癌组织和肿瘤细胞系中BRG1的表达分析

BRG1（brahma—related gene 1）是进化上高度保守的SWI／SNF染色质重塑复合物的成员之一．研究表明：BRG1具有抑瘤基因的特征，可能与肿瘤的发生发展有关．我们采用RT—PCR、Northern杂交和Western blotting证实：肺腺癌细胞系A549和鼻咽癌细胞系HNE2、HNE3、CNE1中无BRG1的表达，而肺鳞癌细胞系NCI-H520、永生化正常人支气管上皮细胞系HBE和鼻咽癌细胞系HONE1、HNE1、CNE2中有BRG1的表达．同时，通过RT—PCR检测10例肺癌组织标本．发现60％（6／10）的肺癌组织中日RGG1的mRNA水平明显下调，而配对正常肺组织中BRG1的mRNA表达未见改变．对29例肺癌组织和10例配对正常肺组织切片进行免疫组化染色，结果显示：肺癌组织中BRG1蛋白表达的阳性率为37．9％（11／29），配对正常肺组织中BRG1蛋白表达的阳性率为90％（9／10），两者的差异有显著性（P〈0．05）．这提示BRG1确实在肺癌组织及多种肿瘤细胞系中表达下调或缺失，在肺癌发病过程中可能起一定的作用．

Analysis of BRG1 Expression in Primary Lung Cancers and Multiple Tumor Cell Lines

BRG1(brahma-related gene 1)is a component of the evolutionarily conserved SWI/SNF chromatin-remodeling complex.Previous studies have shown that BRG1 may be a tumor suppressor and involved in the carcinogenesis of human tumors.Using RT-PCR,Northern hybridization and Western blotting,primary lung cancers and multiple tumor cell lines were screened.Loss of BRG1 expression in several tumor cell lines,including the lung adenocarcinoma cell line A549,and in 60%(6/10)of primary lung cancers was found.The expression of BRG1 protein in 29 primary lung cancers and 10 normal lung tissues by immunohistochemistry were also examined.This result showed that the BRG1 positive rate in primary lung cancers was 37.9%(11/29),and lower than that in normal lung tissues was 90%(9/10).The difference between the BRG1 expression rate in primary lung cancers and normal lung tissues is significant(P < 0.05).It is suggested that down-expression of BRG1 actually occurs in primary lung cancers and some tumor cell lines.BRG1 might play a role in the development of lung cancer.