Expression of miR-146a-5p in breast cancer and its role in proliferation of breast cancer cells

In the present study, the expression level of microRNA-146a-5p (miR-146a-5p) in breast cancer tissue and cell lines was investigated and its effects on proliferation of breast cancer cells. miR-146a-5p expression was detected by reverse transcription-quantitative polymerase chain reaction in breast cancer tissues, paraneoplastic tissue (collected by The Department of Oncology of Changhai Hospital from January 2014 to June 2015), breast cancer cell line MCF-7 and normal breast epithelial cell line MCF 10A. Bioinformatics analysis was conducted to forecast target genes of miR-146a-5p, which was further verified by fluorescent reporter gene detection. The results demonstrated the expression level of miR-146a-5p in breast cancer tissue was significantly higher, compared with paraneoplastic tissue (P<0.01), and the expression level of miR-146a-5p in MCF-7 cells was significantly higher, compared with MCF 10A cells (P<0.01). Overexpression of miR-146a-5p in MCF-7 cells can promote the proliferation, and low expression miR-146a-5p in MCF-7 can inhibit the proliferation. BRCA1 was further identified as a target gene of miR-146a-5p by bioinformatics analysis and fluorescent reporter gene detection. It was concluded that miR-146a-5p is expressed in breast cancer tissue and breast cancer cell line and may regulate the proliferation of MCF-7 via BRCA1.