Cbfa1 expression is enhanced by the immunosuppressant FK506 in the osteoblastic cell line: UMR106

An immunosuppressant FK506 has been reported to induce osteoblast differentiation in vivo [J. Bone Miner. Res. 15 (2000) 1147]. To study the role of FK506 in osteoblast differentiation, we examined the mRNA expressions of several marker genes (Cbfa1, osteopontin, and alkaline phosphatase) in an osteoblastic cell line: UMR106-6. Results showed that the Cbfa1 (osteoblast specific transcription factor) expression in UMR cells was enhanced by treatment with FK506, promoting osteoblast differentiation. The effect was marked when simultaneous treatment with FK506 and dexamethasone was given to UMR cells comparing with the effects of treatment with each substance alone or non-treatment.