Figure 7
From: An autocrine sphingosine-1-phosphate signaling loop enhances NF-κB-activation and survival
S1P-induced secretion of S1P in the malignant tumor cell lines MEL-7 and WM35. WM35 (A.) or MEL-7 (B.) cells were exposed to either vehicle, 3 μM S1P or 10 μM SKi for 10 minutes in the presence of [3H]sphingosine. Secreted [3H]S1P was then extracted from the cell culture medium and analysed by HPTLC. C. MEL-7 cells were treated with 10 μM SKi or vehicle for 4 h. Apoptosis was then induced by addition of 100 ng/ml Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) for 4 h. D. MEL-7 cells were treated with vehicle or 10 μM JTE013 and VPC23019 for 4 h. Apoptosis was induced by addition of TRAIL for 4 h, and cells positive for cleaved caspase-3 was measured using FACS. The bars in panels A-D denote the mean ± SEM of three independent experiments (*, p < 0.05).