SEMA3A and osteosarcoma: Exposure of the osteoblast-like cell MC3T3 and the more differentiated osteosarcoma cells MG-63 and Saos-2 to exogenous Sema3A (300 ng/ml) enhanced alkaline phosphatase activity (Table 1, p < 0.001, p < 0.01 and p < 0.05 respectively), without affecting cell viability (Supplementary Figure S1).