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Title: Retro-inverso forms of gastrin5-12 are as biologically active as glycine-extended gastrin in vitro but not in vivo
Austin Authors: Marshall, Kathryn M;Laval, Marie;Sims, Ioulia;Shulkes, Arthur;Baldwin, Graham S
Affiliation: Department of Surgery, the University of Melbourne, Austin Health, Heidelberg, Victoria, Australia
Issue Date: Dec-2015
Date: 2015-10-22
Publication information: Peptides 2015; 74: 16-22
Abstract: Non-amidated gastrin peptides such as glycine-extended gastrin (Ggly) are biologically active in vitro and in vivo and have been implicated in the development of gastric and colonic cancers. Previous studies have shown that the truncated form of Ggly, the octapeptide LE5AY, was still biologically active in vitro, and that activity was dependent on ferric ion binding but independent of binding to the cholecystokinin 2 (CCK2) receptor. The present work was aimed at creating more stable gastrin-derived 'super agonists' using retro-inverso technology. The truncated LE5AY peptide was synthesized using end protecting groups in three forms with l-amino acids (GL), d-amino acids (GD) or retro-inverso (reverse order with d-amino acids; GRI). All of these peptides bound ferric ions with a 2:1 (Fe: peptide) ratio. As predicted, Ggly, GL and GRI were biologically active in vitro and increased cell proliferation in mouse gastric epithelial (IMGE-5) and human colorectal cancer (DLD-1) cell lines, and increased cell migration in DLD-1 cells. These activities were likely via the same mechanism as Ggly since no CCK1 or CCK2 binding was identified, and GD remained inactive in all assays. Surprisingly, unlike Ggly, GL and GRI were not active in vivo. While Ggly stimulated colonic crypt height and proliferation rates in gastrin knockout mice, GL and GRI did not. The apparent lack of activity may be due to rapid clearance of these smaller peptides. Nevertheless further work designing and testing retro-inverso gastrins is warranted, as it may lead to the generation of super agonists that could potentially be used to treat patients with gastrointestinal disorders with reduced mucosal function.
DOI: 10.1016/j.peptides.2015.09.012
ORCID: 0000-0002-0944-8747
Journal: Peptides
PubMed URL:
Type: Journal Article
Subjects: Gastrins
Gastrointestinal agents
Peptide fragments
Appears in Collections:Journal articles

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