title: Expression of melanocyte stimulating hormone receptors correlates with mammalian pigmentation, and can be modulated by interferons.
abstract: The relationship between melanogenesis and the expression of melanocyte stimulating hormone (MSH) receptors on the surface of melanocytes was examined using sublines generated from the melanotic JB/MS melanoma. JB/MS cells were propagated in long term culture to allow for phenotypic drift in their characteristics of differentiation, and then were cloned; the cloned cells ranged from well differentiated and pigmented to undifferentiated and amelanotic. Spontaneous and MSH-induced melanogenesis in these different lines was measured and correlated with the number of MSH receptors expressed. After 6 months of in vitro culture, the ability of the cells to respond to MSH was significantly reduced, as were the number of MSH receptors expressed; the cells had reduced pigmentation and were relatively undifferentiated histologically. Subsequently, clonally-derived pigmented cells were found to have numbers of surface MSH receptors (approximately 60,000 per cell) and levels of melanogenic activity similar to the original JB/MS cell line. However, an amelanotic clone had an even more dramatically reduced level of pigmentation which correlated with a further decrease in the expression of MSH receptors (less than 1,000 per cell) and the production of a potent melanogenic inhibitor. We also examined the responses of these various sublines to alpha, beta, and gamma-interferons and found significant heterogeneity in their abilities to respond to these cytokines. This study clearly shows that there is a direct correlation between melanogenesis and the expression of MSH receptors on the surface of melanocytes, and that melanogenic inhibitors may be critically involved in the regulation of mammalian pigmentation.
authors: Laboratory of Cell Biology, National Cancer Institute, Bethesda, Maryland 20892.
authors: K
authors: K
authors: Kameyama
authors: P M
authors: PM
authors: Montague
authors: V J
authors: VJ
authors: Hearing
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002999:Clone Cells; D007370:Interferon Type I / Q000494:pharmacology; D007371:Interferon-gamma / Q000494:pharmacology; D007372:Interferons / Q000494:pharmacology*; D008543:Melanins / Q000096:biosynthesis*; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism*; D008544:Melanocytes / Q000378:metabolism*; D008545:Melanoma; D010641:Phenotype; D011979:Receptors, Pituitary Hormone / Q000032:analysis / Q000096:biosynthesis*; D011994:Recombinant Proteins; D014407:Tumor Cells, Cultured
chemical_list: D007370:Interferon Type I; D008543:Melanins; D011979:Receptors, Pituitary Hormone; D011994:Recombinant Proteins; C029446:MSH receptor; D007371:Interferon-gamma; D009074:Melanocyte-Stimulating Hormones; D007372:Interferons