S1P-mediated MT1-MMP–dependent EC migration and morphogenic differentiation does not involve VEGF receptors or sphingosine kinase activity. (A) BAECs were transfected with empty vector (pcDNA3.1) or with MT1-MMP construct and allowed to recover for 40 hours. Transfected cells were allowed to adhere to Matrigel and PTK787/ZK 222 584 (1 μM), DMS (1 μM), or DMSO were added 30 minutes before the addition of 1 μM S1P or 50 ng/mL VEGF. Formation of capillary-like structures was recorded after 6 hours. A representative of 2 independent experiments is shown. Original magnification, × 50. (B) Transfected BAECs were allowed to attach to filters and were then pretreated with PTK787/ZK 222 584 (1 μM), DMS (1 μM), or DMSO (30 minutes). The medium in the lower chambers was replaced with serum-free medium containing either 1 μM S1P or 50 ng/mL VEGF and incubated for 3 hours. Cell migration was quantified and data are expressed as x-fold induction ± SD of nonstimulated control. Results are the means of 2 independent experiments.