SEMA3A and osteosarcoma: Furthermore, M-CSF pre-treated mouse bone marrow derived osteoclast precursors and RAW 264.7 cells (pre-osteoclasts) with exogenous Sema3A (300 ng/ml) prior to addition of human osteosarcoma cell lines significantly inhibited osteoclast formation (Table 1 p < 0.01, p < 0.001), indicative of anti-osteoclast effects.