Downregulation of miR-139-5p promotes prostate cancer progression through regulation of SOX5

Altered expression of microRNAs (miRNAs) was involved in prostate cancer progression. However, how miRNAs contributed to prostate cancer development remained unknown. Here, we reported that miR-139-5p levels were decreased in prostate cancer tumor tissues and prostate cancer cell lines. Transfection of miR-139-5p mimics reduced cell proliferation and migration ability of prostate cancer cells. Western blotting and RT-qPCR showed that elevation of miR-139-5p greatly inhibited SOX5 expression in prostate cancer cells. Through regulation of SOX5, enhanced expression of miR-139-5p downregulated TWIST, decreased N-cadherin and Vimentin expression, suggesting inhibition of epithelial-mesenchymal transition (EMT) process. The dual luciferase assay validated that SOX5 was a direct target of miR-139-5p. Additionally, a significant negative correlation between SOX5 mRNA levels and miR-139-5p levels were detected in prostate cancer tumor tissues. Our study indicated that miR-139-5p functioned as a tumor suppressor in prostate cancer cells by regulation of SOX5, and it might be a promising target for prostate cancer patients.