title: Carcinogenic effects of exogenous and endogenous glucagon-like peptide-2 in azoxymethane-treated mice.
abstract: Glucagon-like peptide-2 (GLP-2) is a nutrient-dependent intestinotropic hormone that promotes intestinal growth, via increased intestinal proliferation and decreased apoptosis, as well as increases in nutrient absorption and barrier function. The long-acting analog h(Gly(2))GLP-2[1-33] is currently being tested for treatment of short bowel syndrome and Crohn's disease. However, the role of GLP-2 in colon carcinogenesis is controversial. To assess the intestinotropic effects of exogenous and endogenous GLP-2, C57BL6/J mice were injected with 1 microg h(Gly(2))GLP-2[1-33]; 30 or 60 ng hGLP-2[3-33], a GLP-2 receptor antagonist; or PBS (4 wk, twice a day, sc). Chronic h(Gly(2))GLP-2[1-33] increased small intestinal weight/body weight (P < 0.001), villus height (P < 0.001), crypt depth (P < 0.001), and crypt cell proliferation, as measured by expression of the proliferative marker Ki67 (P < 0.05-0.01). In contrast, chronic hGLP-2[3-33] decreased small intestinal weight/body weight (P < 0.05) and colon weight/body weight (P < 0.05). To assess the carcinogenic effects of endogenous and exogenous GLP-2, separate mice were injected with azoxymethane (10 mg/kg, 4 wk, every 7 d, ip), followed by 1.5 microg h(Gly(2))GLP-2[1-33], 30 ng hGLP-2[3-33], or PBS (4 wk, twice a day, sc) 2 or 12 wk thereafter. At 10 or 46 wk after azoxymethane treatment, the numbers of aberrant crypt foci increased with h(Gly(2))GLP-2[1-33] (P < 0.001) and decreased with hGLP-2[3-33] (P < 0.01-0.05) treatment. Furthermore, mucin-depleted aberrant foci, consistent with progressive dysplasia, were almost exclusively present in h(Gly(2))GLP-2[1-33]-treated mice (P < 0.01-0.001). Additionally, adenocarcinomas developed in h(Gly(2))GLP-2[1-33]-treated mice but not in those receiving hGLP-2[3-33] or PBS. Taken together, these studies indicate that chronic treatment with GLP-2 enhances colon carcinogenesis, whereas antagonism of the GLP-2 receptor decreases dysplasia, with possible implications for human therapy.
authors.affiliation: Departments of Physiology, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Roman
authors.initials: R
authors.lastname: Iakoubov
authors.forename: Lina M
authors.initials: LM
authors.lastname: Lauffer
authors.forename: Shivangi
authors.initials: S
authors.lastname: Trivedi
authors.forename: Young-In J
authors.initials: YI
authors.lastname: Kim
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Brubaker
mesh_terms: D000818:Animals; D001397:Azoxymethane / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D003110:Colonic Neoplasms / Q000139:chemically induced* / Q000473:pathology; D053767:Glucagon-Like Peptide 2 / Q000494:pharmacology / Q000633:toxicity*; D006801:Humans; D007422:Intestines / Q000187:drug effects* / Q000254:growth & development / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL
chemical_list: D053767:Glucagon-Like Peptide 2; D001397:Azoxymethane