Biological activity and binding of estradiol to SK-Mel 23 human melanoma cells
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...
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| Format: | Article |
| Language: | English |
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Associação Brasileira de Divulgação Científica
2004-01-01
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| Series: | Brazilian Journal of Medical and Biological Research |
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| Online Access: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000600016 |
| _version_ | 1811328186552680448 |
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| author | Sarti M.S.M.V. Visconti M.A. Castrucci A.M.L. |
| author_facet | Sarti M.S.M.V. Visconti M.A. Castrucci A.M.L. |
| author_sort | Sarti M.S.M.V. |
| collection | DOAJ |
| description | 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. |
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| institution | Directory Open Access Journal |
| issn | 0100-879X 0034-7310 |
| language | English |
| last_indexed | 2024-04-13T15:20:45Z |
| publishDate | 2004-01-01 |
| publisher | Associação Brasileira de Divulgação Científica |
| record_format | Article |
| series | Brazilian Journal of Medical and Biological Research |
| spelling | doaj.art-1618d42927f649aa88b5644e4e328c822022-12-22T02:41:40ZengAssociação Brasileira de Divulgação CientíficaBrazilian Journal of Medical and Biological Research0100-879X0034-73102004-01-01376901905Biological activity and binding of estradiol to SK-Mel 23 human melanoma cellsSarti M.S.M.V.Visconti M.A.Castrucci A.M.L.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.http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000600016SK-Mel 23 cell lineHuman melanomaß-estradiolTamoxifenCell proliferationTyrosinase activity |
| spellingShingle | Sarti M.S.M.V. Visconti M.A. Castrucci A.M.L. Biological activity and binding of estradiol to SK-Mel 23 human melanoma cells Brazilian Journal of Medical and Biological Research SK-Mel 23 cell line Human melanoma ß-estradiol Tamoxifen Cell proliferation Tyrosinase activity |
| title | Biological activity and binding of estradiol to SK-Mel 23 human melanoma cells |
| title_full | Biological activity and binding of estradiol to SK-Mel 23 human melanoma cells |
| title_fullStr | Biological activity and binding of estradiol to SK-Mel 23 human melanoma cells |
| title_full_unstemmed | Biological activity and binding of estradiol to SK-Mel 23 human melanoma cells |
| title_short | Biological activity and binding of estradiol to SK-Mel 23 human melanoma cells |
| title_sort | biological activity and binding of estradiol to sk mel 23 human melanoma cells |
| topic | SK-Mel 23 cell line Human melanoma ß-estradiol Tamoxifen Cell proliferation Tyrosinase activity |
| url | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2004000600016 |
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