二乙基亚硝胺诱发大鼠肝癌过程中PC3/BTG2基因表达的变化

目的 探讨PC3/BTG2在肝细胞癌形成过程中的变化趋势及作用.方法 建立改进的二乙基亚硝胺(DEN)诱发的大鼠肝癌模型.免疫组织化学法检测PC3/BTG2蛋白的表达情况,用RT-PCR和Western blot检测诱癌不同时期PC3/BTG2、p53、细胞周期素D1的mRNA和蛋白表达情况.统计学处理采用单因素方差分析.结果 PC3/BTG2蛋白在大鼠肝细胞中主要表达于细胞核,亦可见于部分细胞质,随着DEN诱癌过程的发展,PC3/BTG2的表达有由细胞核向细胞质易位的趋势.在DEN诱发的大鼠肝癌模型中,PC3/BTG2 mRNA早期表达增高,5周达高峰(0.653±0.023),晚期降低(16周为0.312±0.021);p53 mRNA早期增高(5周为0.493±0.027),晚期降低(16周为0.187±0.026);细胞周期素D1 mRNA早期未检测到,晚期增高并达高峰(16周为0.582±0.029).PC3/BTG2蛋白在诱癌早期表达增高,诱癌5周时达高峰(0.630±0.032),成癌后降低(16周为0.113±0.019);p53蛋白在诱癌早期及中期(5～12周)持续增高(12周为1.186±0.049),到成癌后降低(16周为0.622±0.035)l细胞周期素D1在整个诱癌过程中表达都高于正常对照大鼠,在肝癌形成时增高并达高峰(16周为0.912±0.038).结论 PC3/BTG2表达降低可能与HCC进展有密切联系;在肝癌形成过程中,PC3/BTG2与p53的表达可能存在正调控作用,而与细胞周期素D1可能存在负调控作用.

The expression of B-cell translocation gene 2 in diethylnitrosamine-induced primary hepatocellular carcinoma rat model

Objective To investigate the expression and role of B-cell translocation gene 2(BTG2)in the carcinogenesis of hepatocellular carcinoma(HCC).Methods Modified Diethylnitrosamine(DEN)induced primary hepatocellular carcinoma rat model was established.The expression of BTG2,p53 and cyclinD1 was detected by RT-PCR,western blot and immunohistochemistry.Results The BTG2 protein was predominantly localized in the nucleus,with faint cytoplasmic staining in normal liver cells;however,it is mainly a cytoplasmic protein in HCC cells.BTG2 was over-expressed during the early stage after DEN treatment,the expression level peaked at 5 weeks and then it gradually decreased to the normal level after 16 weeks.The expression of cyclin D1 and cyclin E was increased gradually after DEN treatment,and peaked at 16 weeks and 5 weeks respectively.A significant increase in p53 was not observed until 5 weeks after DEN treatment,and it gradually decreased after 16 weeks.Conclusions Decreased expression of BTG2 may be an important step in carcinogenesis of HCC.BTG2 may positively regulate p53 expression and negatively regulate cyclin D1 expression in the carcinogenesis of HCC.