Opposite regulation of tyrosinase and glutathione peroxidase by intracellular thiols in human melanoma cells.

Détails

ID Serval
serval:BIB_BCE3EB84BBA0
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Opposite regulation of tyrosinase and glutathione peroxidase by intracellular thiols in human melanoma cells.
Périodique
Archives of Dermatological Research
Auteur(s)
Benathan M.
ISSN
0340-3696
Statut éditorial
Publié
Date de publication
05/1997
Peer-reviewed
Oui
Volume
289
Numéro
6
Pages
341-346
Langue
anglais
Notes
Publication types: Journal Article - Publication Status: ppublish
Résumé
Conditions of oxidative stress lead to down-regulation of glutathione (GSH) and glutathione peroxidase (GPO), which could be responsible for tyrosinase induction in pigment cells. To address this question, the effects of selective modulation of GSH metabolism on melanogenic parameters of slightly and highly melanized melanoma cells were examined. Under standard culture conditions (100 microM cystine, 100 microM tyrosine), the levels of GSH and the activities of glutathione reductase (GR) and GPO were found to be directly related to the pigmentation of melanoma cells. Exposure to 50 microM buthionine sulfoximine for 72 h decreased tyrosinase activity by 30-50% and GSH levels by more than 95%. In contrast, inhibition of GR activity with bis(chloroethyl)nitrosourea or stimulation of GPO activity with sodium selenite did not affect tyrosinase activity nor pigment formation in the melanoma cells tested. Since cysteine (CysH) is a precursor of the GSH tripeptide, the modulation of tyrosinase and GPO activity by the extracellular cystine concentration was also examined. When the cystine concentration was increased from 0 to 200 microM, a dose-dependent decrease in tyrosinase activity was associated with dose-dependent increases in GPO activity and in cell levels of CysH and GSH. The results indicate that cellular thiols coregulate the activities of tyrosinase and GPO in opposite directions. These interdependent processes could provide melanoma cells with protection against oxidative stress at low as well as at high thiol concentration.
Mots-clé
Buthionine Sulfoximine, Carmustine, Cysteine, Cystine, Glutathione, Glutathione Peroxidase, Humans, Melanins, Melanoma, Monophenol Monooxygenase, Oxidative Stress, Sodium Selenite, Sulfhydryl Compounds, Tumor Cells, Cultured
Pubmed
Web of science
Création de la notice
28/01/2008 9:20
Dernière modification de la notice
03/03/2018 20:57
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