Peptide receptors in human lung tumor cells in culture: vasoactive intestinal peptide (VIP) and secretin interaction with the Calu-1 and SW-900 cell lines.
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1-Methyl-3-isobutylxanthine↗
Biomedical subjects
C Boissard
Publications and source records attributed to C Boissard.
Vasoactive intestinal peptide control of cyclic adenosine 3':5'-monophosphate levels in seven human colorectal adenocarcinoma cell lines in culture.
This study was undertaken to assess the role of vasoactive intestinal peptide (VIP) in the control of cyclic adenosine 3':5'-monophosphate production in colonic tumor cells. Seven human colorectal adenocarcinoma cell lines in culture were investigated (HT-29, HRT-18, SW-480, Caco-2, CO-115, CO-125, and HCT-8R). These cell-lines had a cyclic adenosine 3':5'-monophosphate production system which was very sensitive to VIP but less so to prostaglandin E1 and/or isoproterenol. Nonintestinal human malignant epithelial cells, such as HeLa (cervix) and Caki-1 and Caki-2 (kidney), by contrast, did not respond to VIP. The dose-response relationships of malignant colorectal cells were compared to those obtained with epithelial cells of normal human colon and showed that: (a) maximal responses were observed with 0.1 micro M VIP in both malignant and normal cells; (b) half-maximal responses were elicited by VIP concentrations in the 0.3 to 2 nM range in malignant cells (1.2 nM in normal cells), thus indicating the high apparent affinity of the cells to VIP; and (c) the magnitudes of the responses (stimulated:basal ratios) were highly variable in malignant cells, ranging from 225 in HT-29 cells to 3.5 in Caco-2 cells, but were more constant, in the order of 25, in normal cells. Secretin, a VIP agonist in intestinal tissue, stimulated cyclic adenosine 3':5'-monophosphate accumulation in all colorectal cells, but with a 1000- to 5000-fold lower potency than did VIP. These results show that the VIP-sensitive adenylate cyclase system operates in malignant as well as in normal colon epithelial cells.
Adenocarcinoma↗
Vasoactive intestinal peptide: a potent stimulator of adenosine 3':5'-cyclic monophosphate accumulation in gut carcinoma cell lines in culture.
Vasoactive intestinal peptide (VIP) is a potent and efficient stimulator of adenosine 3':5'-cyclic monophosphate (cAMP) accumulation in a human colon carcinoma cell line, HT 29. cAMP accumulation is sensitive to a concentration of VIP as low as 3x10(-12) M. Maximum VIP-induced cAMP levels were observed with 10(-9) M VIP and are about 200 times above the basal levels. Half-maximum cAMP production was obtained at 3x10(-10) M VIP. (125)I-Labeled VIP was found to bind to HT 29 cells; this binding was competitively inhibited by concentrations of unlabeled VIP between 10(-10) and 10(-7) M. Half-maximum inhibition of binding was observed with 2x10(-9) M VIP. Secretin also stimulated cAMP accumulation in HT 29 cells, but its effectiveness was 1/1000 that of VIP. The other peptides tested at 10(-7) M, such as insulin, glucagon, bovine pancreatic polypeptide, somatostatin, octapeptide of cholecystokinin, neurotensin, and substance P, did not stimulate cAMP accumulation. Prostaglandin E(1) and catecholamines stimulated cAMP production but were 1/2.3 and 1/5.5 as efficient as VIP, respectively. Another malignant cell line from the gut, the human rectal tumor cell line HRT 18, is also sensitive to VIP. In HRT 18 cells, VIP stimulated cAMP accumulation with a maximal effect at 10(-8) M; half-maximum stimulation was observed at about 10(-9) M. These results demonstrate the presence of VIP receptors in two malignant human intestinal cell lines (HT 29 and HRT 18) in culture and provide a model for studying the action of VIP on cell proliferation.
Adenocarcinoma↗
[Measurement of cyclic AMP in the islets of Langerhans of newborn rats. Effect of amino acids].
Radioimmunoassay of cyclic AMP (cAMP) in the islets of Langerhans from 48-64 h old Rats was performed after succinylation of the samples. cAMP was detected at 0.03 nM. The cAMP content of islets increases when L-arginine, L-lysine and L alanine are added together in the incubation medium at a concentration of 5-10 mM each. When phosphodiesterase is inhibited by theophylline the three amino acids considerably increase the cAMP content of islets. Thus an increase in cAMP content of the islets was observed with a concentration of amino acids which is efficient in stimulating the insulin and glucagon secretion.
Alanine↗
Purification of monoiodinated vasointestinal peptide (M125I-VIP) by high pressure liquid chromatography (HPLC).
In our developed reverse phase high performance liquid chromatography, four forms of M125I-VIP have been isolated free from unlabeled VIP and other iodinated components. The quicker eluting M125I-VIP forms (oxidised and reduced) have a consistently and significantly low non-specific binding with specific target cells of VIP (HT-29) as compared to the late eluting forms of VIP. The retention time is considerably increased when the molecule of VIP is fully iodinated.
Animals↗
VIP induces in HT-29 cells 2'5'oligoadenylate synthetase and antiviral state via interferon beta/alpha synthesis.
Vasoactive intestinal peptide (VIP), composed of 28 amino acids, is a multifunctional neurotransmitter. We have demonstrated here that its action on human transformed colonic epithelial (HT-29) cells is mediated through the induction of interferon (IFN) synthesis. We have found that these cells have a functional receptor for IFN alpha 2; binding was specific to either IFN alpha 2 or IFN beta but not to IFN gamma. VIP induced the 2'5'oligoadenylate synthetase (2'5'A synthetase) and the antiviral state with the same efficiency as poly (I).poly (C). The induction of 2'5'A synthetase activity required cellular RNA and protein synthesis, and the maximum induction occurred with 10(-7) M VIP at 24 h. VIP, like some IFN inducers, induced the synthesis of the 70 hsp which, however, preceded the expression of 2'5'A synthetase. VIP treatment caused the induction and secretion of IFN, having a titer value of 32 international units/ml. This IFN has been identified as type beta/alpha, because both 2'5'A synthetase and the antiviral activities were abolished by anti-human IFN beta/alpha antibodies, but not by anti-IFN gamma antibodies. Thus the pathway of VIP action on HT-29 cells may be outlined as 1) binding of VIP, 2) synthesis of 70 hsp, 3) induction of IFN synthesis and its secretion, 4) binding of the secreted IFN to cell surface receptors and 5) turning on the induction of 2'5'A synthetase and antiviral activities.
2',5'-Oligoadenylate Synthetase↗
Processing of vasoactive intestinal peptide and transferrin in human cancerous colonic cells.
Endocytosis of vasoactive intestinal peptide (VIP) and of transferrin (Tf) was comparatively studied in human cancerous colonic HT-29 cells. Cellular depletion in potassium inhibits the internalization of VIP (23%) and to a greater extent (42%) that of Tf. This indicates that clathrin-coated pits are also involved, at least in part, in VIP uptake. The distribution of 125I-Tf- or 125I-VIP-containing vesicles in sucrose gradients revealed low and high density vesicle subpopulations. The low density vesicle subpopulation represented a transient compartment from which incoming vesicles containing N-leucyl-beta naphthylamidase were recycled back to the membrane while those containing beta-hexosaminidase (HA) and ligand were mostly transferred into the high density compartment. Subsequent fusion of the latter with heavy vesicles was demonstrated by the shift of HA and ligand with vesicles that had been prelabeled with horseradish peroxidase (HRP). Simultaneous internalization of Tf-HRP and 125I-VIP showed that both the low and high density vesicle subpopulations comprised of two types of VIP-containing vesicle, as confirmed by the density shift reaction: two-thirds of VIP shifted with the Tf-HRP-containing vesicles to denser fractions and the remaining was found with unshifted vesicles. These findings indicate that the VIP-receptor complex processing in HT-29 cells follows two routes, the major route being common with Tf endocytosis.
Coated Pits, Cell-Membrane↗