DIFFERENTIAL EXPRESSION OF VIP PACAP RECEPTOR GENES IN BREAST, INTESTINAL, AND PANCREATIC-CELL LINES/

Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-ac tivating peptide (PACAP) are structurally-related neuropeptides that f unction as trophic factors in addition to their more classical roles a s neurotransmitters. Binding and molecular cloning studies have shown that their actions are mediated by receptors encoded by at least three different genes. VIP binding has been demonstrated on many tumor type s, and radiolabeled VIP has recently been used as a novel method to lo calize intestinal tumors in humans and their sites of metastasis. To d etermine the receptor subtype and level of gene expression, we screene d breast, intestinal, and pancreatic, cell lines by Northern blot anal ysis. Breast lines expressed VIP/PACAP, receptor mRNA levels comparabl e to intestinal lines, in agreement with the studies showing particula rly high VIP binding in these tumors and their derived cell lines. Pan creatic cell lines expressed mRNA for several receptor types. This ext ends the potential utility of VIP and PACAP in the localization of tum ors, and because VIP and PACAP may regulate the growth rate of some tu mors by autocrine or other mechanisms, the identification of receptor subtypes on these lines sets the stage for studies in which the activi ty of these individual receptors in growth and other processes can be investigated.