THE BIOLOGY OF GASTRIN-FERRIC ION COMPLEXES

Funded Activity Summary

The objective of this project is to understand the biological significance of the complex between ferric ions and non-amidated gastrins (NAGs). This laboratory has shown that NAGs selectively bind 2 ferric ions, and that ferric ion binding is essential for biological activity. Our unpublished data in mouse models indicates a previously unsuspected reciprocal relationship between plasma NAG concentrations and iron status. The significance of this project to human health lies in the facts that NAGs act as growth factors for the normal gastric and colonic mucosa, accelerate the development of both gastric and colorectal cancer, and may be involved in iron overload. The specific aims are: (1) to determine whether or not ferric ions are essential for the stimulation of colorectal carcinoma (CRC) development by NAGs in vivo, (2) to develop orally active NAG inhibitors and analogues, and (3) to confirm the relationship between NAGs and iron status in mice and extend these observations to humans. The research design mirrors the specific aims, and utilises the unique combination of skills of the chief and associate investigators. Firstly, agents (desferrioxamine and bismuth ions) known to block the binding of ferric ions to NAGs will be tested as NAG inhibitors in 4 animal models of CRC development. Secondly, orally active relatives of desferrioxamine and structurally modified gastrin fragments will be tested in CRC cells and in animal CRC models as NAG inhibitors and analogues, respectively. Thirdly, serum gastrins will be measured in mice with altered dietary iron uptake, and in patients with iron overload. These studies are expected to confirm the reciprocal relationship between gastrin concentrations and ferric ion homeostasis observed in mice, and to demonstrate that a similar connection exists in humans. Recognition that metal ions are essential for the biological activity of NAGs may permit the development of novel therapies for colon cancer and iron overload.

Funded Activity Details

Start Date: 01-01-2006

End Date: 01-01-2008

Funding Scheme: NHMRC Project Grants

Funding Amount: $490,020.00

Funder: National Health and Medical Research Council

Research Topics

ANZSRC Field of Research (FoR)

Gastroenterology and Hepatology

ANZSRC Socio-Economic Objective (SEO)

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Other Keywords

colorectal cancer | colorectal cancer (CRC) | gastrin | gastroenterology | gastrointestinal tumorigenesis | iron | proliferation

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