MicroRNA-124 inhibits cell proliferation and migration by regulating SNAI2 in breast cancer

MicroRNA (miRNA) is a type of endogenous non‑coding RNA implicated in various cellular processes. Studies have shown that miR-124 is involved in the malignant progression of cancer, but little is known concerning its potential role in breast cancer. Therefore, the purpose of this study was to conduct a functional analysis of miR-124 in breast cancer, and to identify its target genes in this disease. To this end, we used quantitative real-time PCR to examine the expression level of miR-124 in breast cancer tissue specimens and cell lines. To study the functional significance of miR-124, we overexpressed miR-124 with miR-124 mimics and observed breast cancer cell proliferation, colony formation, migration, and invasion abilities by in vitro cell culture experiments. Target prediction algorithms and luciferase reporter gene assays were used to identify the target genes of miR-124. We also knocked down miR-124 targets using short hairpin RNA (shRNA) constructs, and observed associated breast cancer cell characteristics by in vitro cell culture experiments. We found that miR-124 expression significantly decreased in breast cancer tissues and cells compared to normal tissues and cells. In addition, cell proliferation, colony formation, migration, and invasion were decreased after overexpression of miR-124 in breast cancer cells. Furthermore, we used several algorithms to identify the snail family zinc finger 2 (SNAI2) as a potential target gene of miR-124. The protein expression level and luciferase activity of the 3'-untranslated region of SNAI2 were significantly decreased in breast cancer cells transfected with miR-124 mimics. Cell proliferation, colony formation, migration, and invasion were also decreased after knockdown of SNAI2 by shRNA. In conclusion, our data suggest that miR-124 expression is decreased in breast cancer and plays an important role as a tumor suppressor gene by targeting SNAI2. These findings may reveal novel perspectives for clinical treatments against breast cancer.