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Evidence for alpha-melanocyte-stimulating hormone (alpha-MSH) receptors on human malignant melanoma cells.
Ghanem, G E; Comunale, G; Libert, A; Vercammen-Grandjean, A; Lejeune, F J.
Afiliação
  • Ghanem GE; Laboratory of Oncology and Experimental Surgery, Institut Bordet, Brussels, Belgium.
Int J Cancer ; 41(2): 248-55, 1988 Feb 15.
Article em En | MEDLINE | ID: mdl-2828246
ABSTRACT
The presence of alpha-MSH receptors on human melanoma has so far been suggested in the literature but not proved. We describe a reproducible and specific binding assay of alpha-MSH on human melanoma cells, using a high-specific-activity 125I-labelled hormone (1.5 to 2 mCi/micrograms) with consistent receptor binding (usually exceeding 2 pg/10(6) cells) and stable for 3 weeks. Asynchronized cells in suspension were incubated for 15 min at 37 degrees C with the tracer and various concentrations of unlabelled hormones. Synthetic alpha-MSH was compared to beta-MSH, ACTH1-24, ACTH4-10, beta-LPH, CLIP, CRF, MIF I, A8VP and beta-endorphin. Out of a panel of 8 human melanoma cell lines, 3 showed specific and reproducible alpha-MSH binding curves. No significant binding to human fibroblast and human carcinoma cells was seen. alpha-MSH, beta-MSH and, to a lesser extent ACTH4-10 (a part of the alpha-MSH sequence) were the only peptides able to displace labelled alpha-MSH from its binding sites, indicating the high specificity of the MSH receptor. Affinity constants (Ka) ranged from 10(8) to 10(9) l/mole and the estimated receptor number was 1,000 to 2,000 per cell. We conclude that some human melanoma cell lines expressed specific MSH receptors with stable affinity but which are low in number.
Assuntos
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Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Receptores do Hormônio Hipofisário / Alfa-MSH / Melanoma Limite: Humans Idioma: En Revista: Int J Cancer Ano de publicação: 1988 Tipo de documento: Article País de afiliação: Bélgica
Buscar no Google
Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Receptores do Hormônio Hipofisário / Alfa-MSH / Melanoma Limite: Humans Idioma: En Revista: Int J Cancer Ano de publicação: 1988 Tipo de documento: Article País de afiliação: Bélgica