RUNX2 and osteosarcoma: In fact, overexpression of HDAC1, HDAC2, and HDAC3, which were easily detected in these osteosarcoma cell lines (Supplementary Fig. 4B), had no effect on the Runx2 promoter activity in U2OS cells (Supplementary Fig. 4C), whereas the Runx2 promoter activity was decreased by overexpression of HDAC3 in HCT116 cells12.