Figure 1. S1P increases PDGF-A expression and angiogenesis in human chondrosarcoma cells. (A, B) Chondrosarcoma cells were incubated with S1P (2.5–10 μM) for 24 h; PDGF-A expression was examined by qPCR and Western blot assays (n=4). (C, D) Chondrosarcoma cells were incubated with S1P for 24 h then stimulated with PDGF-A or IgG antibody (1 μg/ml) for 30 min. The conditioned medium (CM) was then collected and applied to endothelial progenitor cells (EPCs) (n=4). EPC migration and tube formation was measured. Results are expressed as the mean ± SEM. *p < 0.05 as compared with the control group; #p < 0.05 as compared with the S1P-treated group.