| Registro completo |
| Provedor de dados: |
BJMBR
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| País: |
Brazil
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| Título: |
The role of calcium, calcium-activated K+ channels, and tyrosine/kinase in psoralen-evoked responses in human melanoma cells
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| Autores: |
Isoldi,M.C.
Pereira,E.A.
Visconti,M.A.
Castrucci,A.M.L.
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| Data: |
2004-04-01
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| Ano: |
2004
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| Palavras-chave: |
8-[Methoxy]-psoralen
SK-Mel 28 cell line
C32TG cell line
Cell proliferation
Cell signaling
Melanoma
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| Resumo: |
8-Methoxy psoralen (8-MOP) exerts a short-term (24 h) mitogenic action, and a long-term (48-72 h) anti-proliferative and melanogenic action on two human melanoma cell lines, SK-Mel 28 and C32TG. An increase of intracellular calcium concentration was observed by spectrofluorometry immediately after the addition of 0.1 mM 8-MOP to both cell lines, previously incubated with calcium probe fluo-3 AM (5 µM). The intracellular Ca2+ chelator BAPTA/AM (1 µM) blocked both early (mitogenic) and late (anti-proliferative and melanogenic) 8-MOP effects on both cell lines, thus revealing the importance of the calcium signal in both short- and long-term 8-MOP-evoked responses. Long-term biological assays with 5 and 10 mM tetraethylammonium chloride (TEA, an inhibitor of Ca2+-dependent K+ channels) did not affect the responses to psoralen; however, in 24-h assays 10 mM TEA blocked the proliferative peak, indicating a modulation of Ca2+-dependent K+ channels by 8-MOP. No alteration of cAMP basal levels or forskolin-stimulated cAMP levels was promoted by 8-MOP in SK-Mel 28 cells, as determined by radioimmunoassay. However, in C32TG cells forskolin-stimulated cAMP levels were further increased in the presence of 8-MOP. In addition, assays with 1 µM protein kinase C and calcium/calmodulin-dependent kinase inhibitors, Ro 31-8220 and KN-93, respectively, excluded the participation of these kinases in the responses evoked by 8-MOP. Western blot with antibodies anti-phosphotyrosine indicated a 92% increase of the phosphorylated state of a 43-kDa band, suggesting that the phosphorylation of this protein is a component of the cascade that leads to the increase of tyrosinase activity.
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| Tipo: |
Info:eu-repo/semantics/article
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000400013
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| Editor: |
Associação Brasileira de Divulgação Científica
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| Relação: |
10.1590/S0100-879X2004000400013
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| Formato: |
text/html
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| Fonte: |
Brazilian Journal of Medical and Biological Research v.37 n.4 2004
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| Direitos: |
info:eu-repo/semantics/openAccess
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