MicroRNA-497 induces cell apoptosis by negatively regulating Bcl-2 protein expression at the posttranscriptional level in human breast cancer

Many studies have demonstrated that microRNAs (miRNAs) may play vital roles in the development of breast cancer. The aim of this study was to examine the expression levels of miR-497 in human breast cancer and investigate whether its potential roles involved targeting Bcl-2. Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to examine the expression levels of miR-497 in 48 breast cancer specimens and six breast cancer cell lines. MTT assay, colony formation assay, and flow cytometry were conducted to explore the potential functions of miR-497 in human MDA-MB-231 breast cancer cells. Correlation analysis and dual-luciferase reporter assay were performed to validate whether Bcl-2 was a direct target of miR-497. The effects of modulating miR-497 on endogenous levels of Bcl-2 were subsequently confirmed via qRT-PCR and western blot. MTT assay, colony formation assay and flow cytometry were used to indicate the roles of endogenous Bcl-2 in breast cancer cells. miR-497 expression levels were significantly decreased in human breast cancer specimens and cell lines (P