S1P induced VEGF mRNA transcription, not mRNA stability. A, Serum-starved SK-N-AS cells were treated with or without S1P (1 μM) for 2 h followed by incubation with ActD (10μg/ml) for different times (0, 1, 2, 3, 4 h) before quantitative real-time PCR was performed. Data are expressed as relative to control, assigning a value of 100% to the control cells. B, Serum-starved SK-N-AS cells were pretreated with ActD (10μg/ml) for 0.5 h and stimulated with S1P (1μM) for another 2 h followed by quantitative real-time PCR. C, SK-N-AS cells were transfected with the VEGF promoter-luciferase construct by Lipofectamine 2000, serum starved and stimulated with S1P (1μM) for another 24 h followed by the assessment of luciferase activity. Data are expressed as fold over control. Results were means ± SE. n=3. *, P < 0.05, **, P < 0.01 versus non S1P-treated control.