Statin Enhances Osteoblast Differentiation by Suppression of Runx2 Overexpression

It has recently been reported that statins, the cholesterol-lowering drug, activate the promoter of the bone morphogenic protein-2 (BMP-2) gene, and stimulate bone forma-tion. However, the mechanism of the stimulation of bone metabolism by statins is not precisely clarified. In this study, we investigated whether statins effect the expression of osteogenic master transcription factors, Runx2/Cbfa1 and Dlx5, as a downstream target of BMP-2. The human osteoblastic osteosarcoma cell line, SaOS-2, was used for this experiment. RT-PCR analysis demonstrated continuous overexpression of Runx2 in SaOS-2, though the expression was hardly observed in normal human osteoblasts. Therefore we considered SaOS-2 a model for the overexpression of the transcription factor. When the osteosarcoma cells were incubated with compactin, there was a significant decrease in mRNA level of Runx2 compared with controls (p