MicroRNA-10b promotes migration and invasion through KLF4 and HOXD10 in human bladder cancer.

The present study was performed to investigate the effect of microRNA-10b (miR-10b) on cell migration and invasion in human bladder cancer (BC). Real-time PCR was performed to detect the expression of miR-10b in BC cell lines. miR-10b mimics, the negative control for mimics, miR-10b inhibitor and the negative control for inhibitor were transfected into BC cell lines and the effects of miR-10b on the migration and invasion of cells were investigated through Transwell assay. Meanwhile, protein levels of KLF4, HOXD10, E-cadherin and MMP14 were measured. Luciferase assays were also performed to validate KLF4 and HOXD10 as miR-10b targets. In vivo metastasis assay was performed to validate if miR-10b can promote BC cell line metastasis in vivo. miR-10b is significantly upregulated in BC cell lines and metastatic tissues. Increased miR-10b expression significantly enhanced BC cell migration and invasion, while decreased miR-10b expression reduced cell migration and invasion. In vivo metastasis assay demonstrated that overexpression of miR-10b markedly promoted BC metastasis. Moreover, KLF4 and HOXD10 were identified as direct targets of miR-10b in BC cells. Silencing of KLF4 or HOXD10 recapitulated the pro-metastatic function. Furthermore, we found that E-cadherin and MMP14 may be the downstream factors of KLF4 and HOXD10 in the suppression of BC metastasis by miR-10b. These data suggest that miR-10b may function as oncogenes in BC cells. Targeting these novel strategies, inhibition of miR-10b/KLF4/E-cadherin axis and miR-10b/HOXD10/MMP14 axis may be helpful as a therapeutic approach to block BC cell metastasis.