ABSTRACT. Osteosarcoma is one of the most common primary bone tumors in children and young adults. In this study, we investigated the role of musculoaponeurotic fibrosarcoma oncogene homolog K (MAFK) in osteosarcoma cell proliferation in vitro and the possible pathways that contributed to MAFK-related osteosarcoma development. We first reported that MAFK was expressed at low levels in an osteosarcoma cell line. Furthermore, a significant correlation between MAFK and the Wnt signaling pathway was observed in osteosarcoma by using a gene microarray assay. We found that expression of MAFK could be induced by Wnt1 in a dose-dependent manner. Furthermore, Wnt1-induced MAFK expression caused a significant increase of cell viability, whereas a Wnt pathway inhibitor, IWR-1-endo, abolished Wnt1-induced effects on MAFK. Finally, cell cycle analysis showed that enhanced cell proliferation might be attributed to re-distribution of the cell cycle. Together, our results suggested that Wnt1-induced MAFK expression promoted cell proliferation in MG63 cells, and that the role of MAFK in osteosarcoma might be closely linked to the Wnt signaling pathway.

Herpes simplex virus thymidine kinase (HSV-TK) and