Data/hora: 09/06/2024 08:26:38

Provedor de dados: 	56	
País: 	Brazil	
Título: 	Biological activity and binding of estradiol to SK-Mel 23 human melanoma cells	
Autores: 	Sarti,M.S.M.V.; Visconti,M.A.; Castrucci,A.M.L.	
Data: 	2004-06-01	
Ano: 	2004	
Palavras-chave: 	SK-Mel 23 cell line; Human melanoma; SS-estradiol; Tamoxifen; Cell proliferation; Tyrosinase activity.	
Resumo: 	Patients expressing estradiol receptors in melanoma cells have been reported to have a better prognosis. We therefore decided to investigate the in vitro effects of ß-estradiol and tamoxifen on the growth and tyrosinase activity of SK-Mel 23 human melanoma cells. Twenty-four-hour treatment with 0.4 nM ß-estradiol inhibited cell proliferation in 30% (0.70 ± 0.03 x 10(5) cells) and increased tyrosinase activity in 50% (7130.5 ± 376.5 cpm/10(5) cells), as compared to untreated cells (1.0 ± 0.05 x 10(5) cells and 4769 ± 25.5 cpm/10(5) cells, respectively). Both responses were completely (100%) blocked by 1 µM tamoxifen. Higher concentrations (up to 1.6 nM) or longer treatments (up to 72 h) did not result in a larger effect of the hormone on proliferation or tyrosinase activity. Competition binding assays demonstrated the presence of binding sites to [2,4,6,7-³H]-ß-estradiol, and that the tritiated analogue was displaced by the unlabeled hormone (1 nM to 100 µM, Kd = 0.14 µM, maximal displacement of 93%) or by 10 µM tamoxifen (displacement of 60%). ß-estradiol also increased the phosphorylated state of two proteins of 16 and 46 kDa, after 4-h treatment, as determined by Western blot. The absorbance of each band was 1.9- and 4-fold the controls, respectively, as determined with Image-Pro Plus software. Shorter incubation periods with ß-estradiol did not enhance phosporylation; after 6-h treatment with the hormone, the two proteins returned to the control phosphorylation levels. The growth inhibition promoted by estradiol may explain the better prognosis of melanoma-bearing women as compared to men, and open new perspectives for drug therapy.	
Tipo: 	Info:eu-repo/semantics/other	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000600016	
Editor: 	Associação Brasileira de Divulgação Científica	
Relação: 	10.1590/S0100-879X2004000600016	
Formato: 	text/html	
Fonte: 	Brazilian Journal of Medical and Biological Research  v.37 n.6 2004	
Fonte: 	info:eu-repo/semantics/openAccess