miR-140-3p inhibits bladder cancer cell proliferation and invasion by targeting FOXQ1

Upregulation of the forkhead box protein Q1 (FOXQ1) promotes bladder cancer (BCa) cell growth and metastasis. Factors affecting FOXQ1 expression at the post-transcriptional level have not yet been identified. We performed cell proliferation, cell invasion, and tumorigenesis experiments to characterize the relationship between FOXQ1 and miR-140-3p. We found that FOXQ1 was significantly upregulated and miR-140-3p was significantly downregulated in BCa tissues. We also identified an inverse correlation between miR-140-3p and FOXQ1 expression in BCa tissues. Overexpression of miR-140-3p reduced FOXQ1 expression, suppressing BCa cell proliferation and invasion. A luciferase assay confirmed that miR-140-3p bound to the 3'-UTR of FOXQ1 mRNA and decreased its expression. In addition, we used a mouse xenograft model to demonstrate that miR-140-3p suppressed tumor cell growth in vivo. Our findings suggest that miR-140-3p suppresses BCa cell proliferation and invasion by directly decreasing FOXQ1 expression.