Advanced search
Start date
Betweenand
(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Biological activity and binding of estradiol to SK-Mel 23 human melanoma cells

Full text
Author(s):
M.S.M.V. Sarti ; M.A. Visconti ; A.M.L. Castrucci
Total Authors: 3
Document type: Journal article
Source: Brazilian Journal of Medical and Biological Research; v. 37, n. 6, p. 901-905, Jun. 2004.
Abstract

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. (AU)

FAPESP's process: 01/02460-1 - Melanopsin: comparative physiology of the gene and of the transduction of the luminous signal in pigmentary cells of fish, amphibians and mammals
Grantee:Ana Maria de Lauro Castrucci
Support type: Research Projects - Thematic Grants