SPP1 and osteosarcoma: Studies have shown that AST significantly reduced the cell proliferation of 3 canine osteosarcoma cell lines, OS 2.4, HMPOS, and D17, by up-regulating the expression of Runx2 [79], type I collagen, osteopontin, and osteocalcin in MG63 cells, and inhibited the mitotic activity of osteosarcoma cells [80].