Sphingomyelinase metabolites control survival and apoptotic death in SH-SY5Y neuroblastoma cells

There is increasing evidence that sphingolipids are involved in cell surviv al, differentiation or commitment to death. The effect of different sphingo lipids and inhibitors of mitogen-activated protein kinase (MAPK) cascade on SH-SY5Y neuroblastoma cell death has been studied. Permeant ceramide analo gues C2-Cer, C8-Cer, and C8-Cer-1-phosphate, but not dihydro C2-Cer induce apoptosis, as shown by Hoechst staining. Inhibition of ceramidase and sphin gosine kinase, as well as incubation with sphingosine, decreases cell viabi lity, measured as 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium brom ide reduction, whereas addition of sphingosine-1-phosphate increases prolif eration. Both PD98059 (MAPKK inhibitor) and SB202190 (p38 MAPK inhibitor) d ecreased viability, but only SB202190 abolished the effect of ceramide. The se results suggest that in SH-SY5Y neuroblastoma cells, death is signalled by increases in ceramide, ceramide-phosphate or sphingosine content through p38 MAPK pathway while survival requires MAPK and high sphingosine-1-phosp hate/ceramide ratio. (C) 2000 Elsevier Science Ireland Ltd. All rights rese rved.