DIFFERENTIAL EXPRESSION AND FUNCTION OF PACAP AND VIP RECEPTORS IN 4 HUMAN COLONIC ADENOCARCINOMA CELL-LINES

Human colonic adenocarcinoma cell lines have conserved several feature s of the native tissue. Among these is the expression of cell surface receptors for hormones and neurotransmitters that may be involved in t he regulation of proliferation and differentiation processes in these cancer cells. Here, we confirm that high-affinity binding sites for th e Vasoactive Intestinal Polypeptide (VIP) and for the VIP analogue Pit uitary Adenylate-Cyclase Activating Polypeptide (PACAP), were expresse d in 4 human colonic adenocarcinoma cell lines, HT29, SW403, DLD-1 and Caco-2, that spontaneously displayed variable phenotypic properties i n culture. We demonstrated that: after long-term treatments, VIP and P ACAP significantly reduced cell proliferation in the 4 cell lines and modulated intracellular cAMP and cGMP levels. Furthermore, conspicuous differences were observed from one cell-type to another concerning ex pression of the receptor subsets or the effects of the neuropeptides o n cell growth and on cyclic nucleotides production. (C) 1998 Elsevier Science Inc.