MicroRNA-3941 targets IGF-1 to regulate cell proliferation and migration of breast cancer cells.

We aimed to investigate the effects and regulatory mechanism of microRNA-3941 (miR-3941) in the progression of breast cancer. The expression of miR-3941 and insulin-like growth factor 1 (IGF-1) was determined in breast cancer tissues and cell lines. A miR-3941 mimics, inhibitor, and scramble RNA were individually transfected into the cancer cells. Then, the effects of overexpression and suppression of miR-3941 on cell viability, migration, and invasion, as well as on the expression of epithelial-mesenchymal transition (EMT)-related proteins (E-cadherin, N-cadherin, and vimentin) were further investigated. In addition, luciferase reporter analysis was performed to confirm whether IGF-1 was the potential target of miR-3941. Small interfering RNA targeting IGF-1 was transfected into the cells to further investigate whether miR-3941 regulated the breast cancer cell migration and invasion by targeting IGF-1. The inverse expression of miR-3941 (downregulated) and IGF-1 (upregulated) was observed in the breast cancer tissues and cells. The overexpression of miR-3941 significantly inhibited the breast cancer cell viability and suppressed cell migration and invasion. In addition, IGF-1 was confirmed as the target of miR-3941, and IGF-1 expression was negatively regulated by miR-3941. The knockdown of IGF-1 significantly reversed the inhibitory effects of miR-3941 overexpression on cell migration, invasion, and the EMT-related proteins. Our results indicate that miR-3941 is downregulated in breast cancer cells, and the downregulation of miR-3941 may promote breast cancer cell proliferation, migration, and invasion through not targeting IGF-1 expression. miR-3941 and IGF-1 may serve as diagnostic markers or potential targets for breast cancer treatment.