Sphingosine-induced c-jun expression: differences between sphingosine- and C2-ceramide-mediated signaling pathways.
Sphingolipids such as ceramide and sphingosine are putative intracellular signal mediators in cell differentiation, growth inhibition and apoptosis. Previously, we reported that C2-ceramide induced c-jun expression in apoptosis of human leukemia HL-60 cells. Here we report that sphingosine also induced c-jun expression in apoptosis of HL-60 cells. Sphingosine-induced c-jun expression was stimulated by H-89, a protein kinase A inhibitor, whereas C2-ceramide-induced c-jun expression was inhibited by protein kinase C inhibitors. Furthermore, H-89 potentiated sphingosine-induced but not C2-ceramide-induced growth inhibition. These results suggest that sphingosine and C2-ceramide might induce c-jun expression and apoptosis in distinct signaling pathways.
Department of Internal Medicine, Osaka Dental University, 8-1 Kuzuhahanazono-cho, Hirakata, Osaka, Japan. sawai@cc.osaka-dent.ac.jp
Hirofumi
H
Sawai
Toshiro
T
Okazaki
Naochika
N
Domae
D002455:Cell Division / Q000187:drug effects; D002518:Ceramides / Q000502:physiology*; D005786:Gene Expression Regulation / Q000187:drug effects*; D018922:HL-60 Cells; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology*; D013110:Sphingosine / Q000494:pharmacology*; D013449:Sulfonamides
D002518:Ceramides; D007546:Isoquinolines; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D013449:Sulfonamides; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; D013110:Sphingosine