Forkhead box C1 is targeted by microRNA-133b and promotes cell proliferation and migration in osteosarcoma.

Forkhead box C1 (FOXC1) has been demonstrated to act as an oncogene in a number of malignant tumors, though its underlying mechanism of action in osteosarcoma (OS) remains unknown. The present study evaluated the expression and regulatory role of FOXC1 in OS. Reverse transcription-quantitative polymerase chain reaction and western blot data indicated that FOXC1 was significantly upregulated in OS tissues and cell lines when compared with adjacent non-tumor tissues (P<0.001) and normal human osteoblast cells (P<0.01), respectively. Moreover, levels of FOXC1 expression were significantly higher in OS at advanced clinical stage (III-IV) when compared with that at low clinical stage (I-II; P<0.001). Knockdown of FOXC1 expression caused a significant decrease in the proliferation and migration of OS U2OS cells (P<0.01), while overexpression of FOXC1 significantly promoted U2OS cell proliferation and migration (P<0.01), relative to control U2OS cells. Furthermore, FOXC1 was identified as a direct target of microRNA (miR)-133b, a reported tumor-suppressive miR in OS. The protein expression of FOXC1 was negatively regulated by miR-133b in U2OS cells (P<0.01), and miR-133b expression was inversely correlated with FOXC1 expression in OS. In conclusion, the present study demonstrated that FOXC1, targeted by miR-133b, may promote cell proliferation and migration in OS. Thus, FOXC1 may be a potential therapeutic target in the treatment of OS.