Effects of Sphingosine 1-phosphate on apoptosis of B16 melanoma cells

초록

The bioactive sphingolipid metabolite sphingosine-1-phosphate (S1P) is the ligand for a family of five G protein-coupled receptors, the Edg (endothelial differentiation gene) receptors, which includes Edg-1, 3, 5, 6, and 8. Activation of these GPCRs by S1P regulates diverse processes, including cell migration, angiogenesis, vascular maturation, heart development, and neurite retraction. A few studies of the relationship between S1P and melanoma cells have been reported. They reported that S1P inhibited motility of cultured melanoma cells. Melanocytes and melanoma cells are known to be of neural crest origin. The effects of S1P on apoptosis of neural cells are diverse depending on the cell line. There has been no report on the effect of S1P on melanoma cell growth. In the present study, we investigated in vitro the effects of S1P on B16 melanoma cell proliferation. For the first time, we confirmed the expression of Edg-1, 3, and 5 on cytoplasm of B16 melanoma cells by Western blot and immunocytochemistry method. We observed the inhibitory effect of S1P on proliferation of B16 melanoma cells by in vitro culture in a dose-dependent pattern. We also observed that S1P at a dose of 10 mmol induced apoptosis of B16 melanoma cells through TUNEL assay. Currently we are researching whether S1P induces the activation of caspases and JNK in order to confirm the signaling pathway of apoptosis induced by S1P in B16 melanoma cell line.