A human melanoma-derived cell line (IGR39) with a very high number of vasoactive-intestinal-peptide (VIP) receptors. 2. Effect of VIP on cAMP production and on cell-surface VIP-binding sites.
Vasoactive intestinal peptide (VIP) stimulated in a dose-dependent manner the accumulation of cAMP in human melanoma-derived cell line IGR39. The maximal effect (about 100 times the basal level) was observed with 10 nM VIP. Half-maximum cAMP production was obtained at 0.78 nM VIP. VIP-related peptides were also potent in stimulating the cAMP production in IGR39 cells. The order of potency was VIP much greater than peptide histidine-methioninamide greater than human growth-hormone-releasing factor(1-44) greater than secretin greater than glucagon. Using the same conditions, IGR37 cells, a metastasic counterpart of IGR39 cells, displayed a weak stimulation of cAMP production. After exposure of IGR39 cells to 10 nM VIP, the cAMP response to a new stimulation by VIP was strongly reduced. This desensitization of IGR39 cells to VIP was rapid (t1/2 less than 2 min) and homologous. Preincubation of IGR39 cells in the presence of native VIP induced disappearance of the VIP-binding sites at the cell surface. This phenomenon was dependent on time and VIP concentration. Maximum effect (loss of 80% of binding capacity) was obtained after exposure of the cells at 37 degrees C with a VIP concentration of 1 microM. The t1/2 of maximum disappearance was less than 2 min and the concentration of VIP giving half-maximum decrease in binding of mono[125I]iodinated VIP (125I-VIP) was 8 nM. This phenomenon was also reversible since 85% of the VIP-binding capacity could be restored in less than 1 h by incubating IGR39 cells in a VIP-free medium. The IGR39 cell line should be a useful model for further study of the structure and function of the human VIP receptor.
Martin
J M
JM
Institut de Chimie Biologique, Unité Associée au Centre National de la Recherche Scientifique no. 202, Université de Provence, Marseille, France.
Luis
J
J
Marvaldi
J
J
Pichon
J
J
Pic
P
P
D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008545:Melanoma / Q000378:metabolism; D011964:Receptors, Gastrointestinal Hormone / Q000187:drug effects / Q000378:metabolism*; D018005:Receptors, Vasoactive Intestinal Peptide; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism*; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism / Q000494:pharmacology*
D011964:Receptors, Gastrointestinal Hormone; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP