MiR-337-3p suppresses migration and invasion of breast cancer cells by downregulating ESRP1

Breast cancer (BC) is a common malignant tumor in women, and a considerable number of studies show that aberrant expression of miRNA is correlated with BC development. By analyzing TCGA-BRCA database through bioinformatics method, this study disclosed that miR-337−3p was significantly low in BC tissue and might be a cancer inhibitor in BC. To explore the effect and potential mechanism of miR-337−3p in BC, qRT-PCR was used in this study to indicate that the expression of miR-337−3p was downregulated in BC cells. Then, the effects of miR-337−3p on BC cells were detected by western blot, Cell Counting Kit-8 (CCK-8), wound healing and Transwell assays. After upregulating miR-337−3p expression, the cell viability, migration, invasion and epithelial-mesenchymal transition (EMT) of BC cells were markedly inhibited while cell apoptosis remarkably increased. Besides, it was predicted and identified by bioinformatics analysis and dual-luciferase assay that ESRP1 was a target gene of miR-337−3p. Finally, the progression and EMT of BC cells were promoted after upregulating ESRP1 expression level. However, upregulating miR-337−3p as well as ESRP1 reduced the promotion on the malignant phenotype of BC cells. This result revealed that miR-337−3p could inhibit ESRP1 expression to perform its biological functions. In conclusion, it was illustrated in this study that miR-337−3p is a tumor-inhibitor of BC and plays its regulatory role via its downstream gene ESRP1.