miR-1258 Regulates Cell Proliferation and Cell Cycle to Inhibit the Progression of Breast Cancer by Targeting E2F1

OBJECTIVE: This study is designed to clarify that miR-1258 targets E2F1 to regulate the proliferation and cell cycle of breast cancer (BC) cells and consequently suppress the progression of BC. METHODS: Bioinformatics analysis was used to analyze the differentially expressed genes in BC. The expression of miR-1258 and E2F1 mRNA in BC cell lines and immortalized breast epithelial cell lines were detected by qRT-PCR. The proliferation and growth activity of BC cells were detected by MTT and colony formation assays. The apoptosis and cell cycle of BC cells were detected by flow cytometry and the targeting relationship between miR-1258 and E2F1 was identified by dual-luciferase assay. RESULTS: The expression of miR-1258 was decreased while that of E2F1 was increased in BC cells. Overexpression of miR-1258 and silencing E2F1 could inhibit the cell proliferation and growth, block cells in the G0/G1 phase, and promote cell apoptosis. Besides, miR-1258 inhibited cell proliferation and growth, block cells in the G0/G1 phase, and promote cell apoptosis by downregulating E2F1. CONCLUSION: miR-1258 regulates the proliferation and cell cycle to inhibit the progression of BC by targeting and downregulating E2F1.