Yi, Seh Yoon Han, Seon Kyu Park, Mee Kyung Yoo, Young Sook 2024-01-21T03:01:13Z 2024-01-21T03:01:13Z 2021-09-01 2006-06-30 1738-642X https://pubs.kist.re.kr/handle/201004/135388 Sphingolipid metabolites regulate many aspects of cell proliferation, differentiation, and apoptosis. In the present study, we have assessed the effects of the novel phytosphingosine derivative, N-acetylphytospingosine (NAPS), on the depigmentation of murine B16F10 melanoma cells, and have also attempted to identify the possible signaling pathway involved, in comparison with C-2-ceramide. NAPS and C-2-ceramide both inhibited the growth of the B16F10 cells in a dose-dependent manner. Melanin content and tyrosinase activity were significantly reduced in response to treatment with NAPS and C2-ceramide at concentrations in a range between 1-5 mu M. However, the levels of tyrosinase mRNA, as well as the levels of tyrosinase related protein-1 (TRP-1) and tyrosinase related protein-2 (TRP-2) genes and the level of tyrosinase protein remained unaffected by treatment with either NAPS or C2-ceramide. We also attempted to determine the signaling pathway exploited by NAPS and C2-ceramide. Interestingly, the phosphorylation of Akt/PKB at serine 473 by NAPS was reduced at the 5 minute mark, whereas C2-ceramide induced the phosphorylation of Akt/PKB at serine 473. Finally, Akt/PKB activity in the NAPS-treated cells was elevated in comparison with the untreated cells. LY294002, a specific PI3-K inhibitor which is located upstream of Akt/PKB, inhibited the phosphorylation of Akt/PKB, but induced an increase in melanin synthesis. These results suggest that the activation of Akt/PKB at serine 473 is related with the suppression of melanin production in the B16F10 mouse melanoma cells. Therefore, the mechanisms exploited by NAPS and C-2-ceramide responsible for the depigmentation of B16F10 cells were concluded to involve the inhibition of melanosomal tyrosinase activity. English KOREAN SOC TOXICOGENOMICS & TOXICOPROTEOMICS PROTEIN-KINASE-C SIGNAL-TRANSDUCTION MELANOGENESIS CERAMIDE TYROSINASE DIFFERENTIATION PROLIFERATION PATHWAY PIGMENTATION INHIBITION Activation of Akt/PKB at serine 473 by N-acetylphytosphingosine (NAPS) and C-2-ceramide reduces melanin synthesis in B16F10 mouse melanoma cells Article 1 MOLECULAR & CELLULAR TOXICOLOGY, v.2, no.2, pp.81 - 88 MOLECULAR & CELLULAR TOXICOLOGY 2 2 81 88 scie 000243596400002 Biochemistry & Molecular Biology Toxicology Biochemistry & Molecular Biology Toxicology Article PROTEIN-KINASE-C SIGNAL-TRANSDUCTION MELANOGENESIS CERAMIDE TYROSINASE DIFFERENTIATION PROLIFERATION PATHWAY PIGMENTATION INHIBITION N-acetylpytosphingosine (NAPS) C-2-ceramide Akt/PKB melanogenesis B16F10