RUNX2 and osteosarcoma: Furthermore, 1,25(OH)2D3 suppressed the expression of Runx2 during osteoblast differentiation, which in turn inhibited the expression of downstream genes, such as ALP and BSP. Similarly, it has been reported that 1,25(OH)2D3 suppresses Runx2 expression within 24 h in MC3T3 and rat osteosarcoma (ROS) 17/2.8 cells via the binding of vitamin D receptor (VDR) to vitamin D response element (VDRE) and Runx2 autonomously suppresses its own expression [18].