miR-143 and miR-145 inhibit stem cell characteristics of PC-3 prostate cancer cells.

Emerging evidence demonstrates that cancer stem cells (CSCs) are the critical drivers of tumor progression and metastasis. The microRNAs (miRNAs) may play a crucial role in repressing/promoting metastasis of cancer by regulating CSCs. A previous study showed that miR-143 and miR-145 play an important role in regulating bone metastasis of prostate cancer (PCa), but the exact mechanism of regulation of bone metastasis of PCa is not fully understood. In this study, we found that overexpression of miR-143 and miR-145 inhibited the cell viability and colony formation of PC-3 cells from PCa bone metastasis. Furthermore, miR-143 and miR-145 suppressed tumor sphere formation and expression of CSC markers and 'stemness' factors including CD133, CD44, Oct4, c-Myc and Klf4 in PC-3 cells. The study further found that miR-143 and miR-145 inhibit bone invasion and tumorigenicity of PC-3 cells in vivo. Collectively, these findings demonstrate that miR-143 and miR-145 inhibit CSC properties of PC-3 cells and suggest that miR-143 and miR-145 may play a significant role in the bone metastasis progression of PCa by regulating CSC characteristics.