Anti-inflammatory and anti-invasive effects of alpha-melanocyte-stimulating hormone in human melanoma cells.
Alpha-melanocyte stimulating hormone (alpha-MSH) is known to have pleiotrophic functions including pigmentary, anti-inflammatory, antipyretic and immunoregulatory roles in the mammalian body. It is also reported to influence melanoma invasion with levels of alpha-, beta- and gamma-MSH correlated clinically with malignant melanoma development, but other studies suggest alpha-MSH acts to retard invasion. In the present study, we investigated the action of alpha-MSH on three human melanoma cell lines (HBL, A375-SM and C8161) differing in metastatic potential. alpha-melanocyte-simulating hormone reduced invasion through fibronectin and also through a human reconstructed skin composite model for the HBL line, and inhibited proinflammatory cytokine-stimulated activation of the NF-kappaB transcription factor. However, A375-SM and C8161 cells did not respond to alpha-MSH. Immunofluorescent microscopy and Western blotting identified melanocortin-1 receptor (MC-1R) expression for all three lines and MC-2R on HBL and A375-SM lines. Receptor binding identified a similar affinity for alpha-MSH for all three lines with the highest number of binding sites on HBL cells. Only the HBL melanoma line demonstrated a detectable cyclic adenosine monophosphate (cAMP) response to alpha-MSH, although all three lines responded to acute alpha-MSH addition (+(-)-N(6)-(2-phenylisopropyl)-adenosine (PIA)) with an elevation in intracellular calcium. The nonresponsive lines displayed MC-1R polymorphisms (C8161, Arg (wt) 151/Cys 151; A375-SM, homozygous Cys 151), whereas the HBL line was wild type. Stable transfection of the C8161 line with wild-type MC-1R produced cells whose invasion was significantly inhibited by alpha-MSH. From this data, we conclude that alpha-MSH can reduce melanoma cell invasion and protect cells against proinflammatory cytokine attack in cells with the wild-type receptor (HBL).
Eves
P
P
University Section of Medicine, Division of Clinical Sciences, Northern General Hospital, Sheffield S5 7AU, UK.
Haycock
J
J
Layton
C
C
Wagner
M
M
Kemp
H
H
Szabo
M
M
Morandini
R
R
Ghanem
G
G
García-Borrón
J C
JC
Jiménez-Cervantes
C
C
Mac Neil
S
S
D016207:Cytokines / Q000494:pharmacology; D006801:Humans; D007249:Inflammation; D015603:Keratinocytes; D008545:Melanoma / Q000473:pathology*; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D012878:Skin Neoplasms / Q000473:pathology*; D014407:Tumor Cells, Cultured; D000521:alpha-MSH / Q000494:pharmacology*
D016207:Cytokines; D000521:alpha-MSH