BRCA1在乳腺癌细胞系中负调控miR-146a并抑制其促癌功能

摘要

Objective To investigate the regulation of BRCA1 on miR-146a and the biological functions of miR-146a in breast cancer cells. Methods Western blot and real time PCR assays were performed to examined the regulation of BRCA1 on miR-146a. Bioinformatics tools were applied to analyze the bidirectional regulation between BRCA1 and miR-146a. MTS, colony formation, transwell assays were selected to test the effects of miR-146a mimic and inhibitor on cell growth and proliferation, migration and invasion of MCF-7 cells. Results The loss of endogenous BRCA1 greatly attenuated the expression of miR-146a. By means of promoter analysis, the results showed that BRCA1 was able to bind the promoter region of miR-146a and regulate its expression, while miR-146a could be partially complementary to bind BRCA1 3'UTR, suggesting that BRCA1 modulated miR-146a in a negative feedback mechanism. miR-146a mimic promoted the ability of cell growth, proliferation, migration and invasion, while miR-146a inhibitor had the reversed function. Conclusions BRCA1 negatively regulates miR-146a and inhibits its tumor promoting functions in breast cancer cells.%目的在乳腺癌细胞系中，研究 BRCA1基因对 miR-146a的调控，以及 miR-146a 的细胞学功能。　　方法采用 Western blot 和实时定量 PCR 检测 BRCA1基因对 miR-146a 的调控；利用生物信息学分析软件对BRCA1以及 miR-146a 的相互调控进行分析；运用 MTS、克隆形成、Transwell 等实验技术检测 miR-146a 高表达及敲降对 MCF-7细胞生长增殖、侵袭迁移等能力的影响。　　结果该研究发现 BRCA1缺失的情况下，miR-146a 表达显著表达升高。通过对 miR-146a 启动子区分析发现BRCA1可以与 miR-146a 启动子区结合并调控其表达，同时 miR-146a 可以与 BRCA13'UTR 不完全互补结合，这提示 BRCA1对 miR-146a 的调控是一种负反馈作用机制。该研究还发现 miR-146a 高表达可以促进细胞生长增殖和侵袭迁移的能力，而 miR-146a 敲降后却可以抑制细胞这些表型。　　结论在乳腺癌细胞中，BRCA1通过负调控 miR-146a 的表达来抑制其促癌功能。