Defining Iron And Haem-induced Pro-carcinogenic Pathways Of Colorectal Cancer
Funder
National Health and Medical Research Council
Funding Amount
$566,277.00
Summary
Colorectal cancer is very common in Western society. Population studies have reported that high consumption iron-containing foods and red meat, the latter being a source of both haem and iron, are risk factors for colorectal cancer. This study will identify the levels of dietary haem and iron that promote colorectal cancer development. Also, it will determine the mechanisms and relative contribution of iron and haem to pro-carcinogenic pathways that result in colorectal cancer.
Progastrin Derived Peptides: Biological Activities And Functions In The Gastrointestinal Tract
Funder
National Health and Medical Research Council
Funding Amount
$454,500.00
Summary
Gastrin is a hormone from the stomach which aids digestion by stimulating acid secretion. However too much acid can cause ulcers of the gastrointestinal tract. Gastrin also stimulates the growth of the lining of the stomach and intestines. This growth promoting effect is important for the development of the gastrointestinal tract before birth and may also be involved in a number of cancers especially colon cancer. Several different forms of gastrin are made by endocrine cells of the stomach and ....Gastrin is a hormone from the stomach which aids digestion by stimulating acid secretion. However too much acid can cause ulcers of the gastrointestinal tract. Gastrin also stimulates the growth of the lining of the stomach and intestines. This growth promoting effect is important for the development of the gastrointestinal tract before birth and may also be involved in a number of cancers especially colon cancer. Several different forms of gastrin are made by endocrine cells of the stomach and by cancers of the colon. It seems that the different types of gastrins have different effects and act through distinct receptors, but we do not know which are the most important forms and whether all forms are biologically active. The amount, type and activity of the different gastrins, and the regions of the molecule that are essential for biological activity, will be investigated using cell lines, animal models that overproduce too much gastrin, animal models of colon cancer and in patients with colon cancer. Colorectal carcinoma (cancer of the large bowel) is the second most common cause of cancer death. A successful outcome will result in the development of assays for the early diagnosis and monitoring of bowel cancer and the potential for novel treatments such as gastrin receptor antagonists and radiolabelled gastrin analogues for radiotherapy.Read moreRead less
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 NAG ....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.Read moreRead less
CpG Island Methylation In Microsatellite Stable Colorectal Cancers: Epigenetics Or Epiphenomenon?
Funder
National Health and Medical Research Council
Funding Amount
$245,402.00
Summary
For years researchers have known that changes in the sequence of DNA in genes within a cell can lead to cancer, particularly when those changes are passed on to daughter cells. This has lead to massive research interest in the field of cancer genetics. In the last few years, it has become clear that as well as changes in DNA, other more subtle changes can be passed on. These changes, which do not directly involve changes in DNA sequence, are referred to as epigenetic changes. One of the most com ....For years researchers have known that changes in the sequence of DNA in genes within a cell can lead to cancer, particularly when those changes are passed on to daughter cells. This has lead to massive research interest in the field of cancer genetics. In the last few years, it has become clear that as well as changes in DNA, other more subtle changes can be passed on. These changes, which do not directly involve changes in DNA sequence, are referred to as epigenetic changes. One of the most commonly recognised epigenetic changes is known as methylation. Methylation of genes can switch that gene off, meaning that the protein normally made is no longer present in the cell. This can have profound effects on the way cells behave, and importantly may be involved in the development of cancer. In this study, we will look at a group of colorectal cancers that show abnormally high amounts of DNA methylation , to test our hypothesis that these cancers share a common origin that is distinct from the usual type of bowel cancer. The findings will be important, as they may allow us to show that all bowel cancers are not the same, and that simple gene testing may be able to identify the different subtypes. If bowel cancers can be classified according to the way in which they have developed, then this will help us to understand what causes them why some are more aggressive than others, and why some may respond differently to existing or future cancer treatments.Read moreRead less
Studies Of Genetic Predisposition To Develop Serrated Neoplasia In The Colorectum.
Funder
National Health and Medical Research Council
Funding Amount
$308,291.00
Summary
Colorectal Cancer was once believed to develop only from a certain kind of polyp in the colon called the adenoma. However, recently another type of polyp called the hyperplastic polyp was found to also be capable of producing a cancer. In this proposal, we will look at the possibility that the predisposition to form hyperplastic polyps may be inherited in families.
Regulation Of Mutational Load By Chemopreventive Agents And Implications For Molecular Pathogenesis Of Colorectal Cancer
Funder
National Health and Medical Research Council
Funding Amount
$423,750.00
Summary
In Australia colorectal cancer is the second most common cause of cancer death, however the morbidity and mortality of colorectal cancer is currently not under control. Identification of safe and practical preventive agents should aid control. There is increasing evidence that colorectal cancer is associated with endogenous (internall) and exogenous (external) factors. They cause damage to DNA which might lead to tumour development if the damage is not repaired. This study will first identify th ....In Australia colorectal cancer is the second most common cause of cancer death, however the morbidity and mortality of colorectal cancer is currently not under control. Identification of safe and practical preventive agents should aid control. There is increasing evidence that colorectal cancer is associated with endogenous (internall) and exogenous (external) factors. They cause damage to DNA which might lead to tumour development if the damage is not repaired. This study will first identify the ability of preventive agents (aspirin-like drugs, fish oil, and antioxidants) to regulate DNA damage, then examine the effect of combination of the agents. It will finally determine the ability of agents, or combination of agents, to prevent development of colorectal cancer using two animal models. Prevention of human CRC by such a strategy should be feasible. First, evidence indicates that DNA damage is important in tumour initiation. Second, exogenous regulation of DNA damage, repair and removal seems possible. Epidemiological studies have suggested that that 30-70% of cancer can potentially be prevented with proper adjustment of diets (fat, fibre, resistant starch) and supplements of drugs (NSAIDs) or antioxidants (Vitamin, Selenium). Third, preventive strategies are likely to be feasible. At the population level, they would need to be safe and manageable in the context of dietary lifestyle, but this can be achieved through a range of food technology developments. In individuals at high risk, personalised preventive strategies become feasible through doctor-patient contact. This study focuses on regulation of DNA damage, and its repair and removal during the early stage of tumour development. The study will provide information if preventive agents, alone or in combination, provide a promising strategy for colorectal cancer through reduction of genetic damage. They might also identify new biomarkers that facilitate testing in humans.Read moreRead less
Population-based Detection Of Hereditary Non-polyposis Colorectal Cancer: Development Of New Best Practice
Funder
National Health and Medical Research Council
Funding Amount
$356,250.00
Summary
Approximately 1-2% of all large bowel cancers are thought to be caused by inherited defects in genes involved in the repair of DNA. These cancers are indistinguishable from those that occur in the general population and this has made it difficult to identify individuals and families with the defective gene. It has been estimated that only about 10-20% of individuals affected by this familial cancer syndrome are being referred to specialized genetic service centres for testing. The large majority ....Approximately 1-2% of all large bowel cancers are thought to be caused by inherited defects in genes involved in the repair of DNA. These cancers are indistinguishable from those that occur in the general population and this has made it difficult to identify individuals and families with the defective gene. It has been estimated that only about 10-20% of individuals affected by this familial cancer syndrome are being referred to specialized genetic service centres for testing. The large majority of familial colorectal cancers occur in young patients aged less than 60 years at diagnosis. Identification of these cases would allow genetic testing to be carried out on other family members who might also carry the mutant gene, thus allowing regular surveillance and a far greater likelihood of early detection and therefore cure. The aim of this project is to use a relatively simple laboratory-based method to test for the possibility that colorectal cancer in young patients (<60 years) may be inherited. From our preliminary data we expect that about 2% of all large bowel cancers, or 20 cases per year in Western Australia, may be familial. These individuals will be referred to Genetic Services WA for proper evaluation of their family history for cancer and for further DNA testing in an attempt to identify the defective gene. For positive cases, affected family members could then be tested for the gene after appropriate genetic counselling.Read moreRead less
Role Of Gastrin Prohormones In The Development Of Gastrointestinal Cancers
Funder
National Health and Medical Research Council
Funding Amount
$612,885.00
Summary
Gastrin is a stomach hormone which increases acid secretion and the growth of the stomach and bowel. This growth promoting effect may be involved in a number of cancers particularly colon cancer. The different types of gastrin have different effects but we do not know which forms are important and whether all are active. The types and activity of different gastrins will be investigated using cell lines, animal models and colon cancer patients with the view of establishing new treatments.
Colorectal carcinoma (cancer of the large bowel) is the second most common cause of cancer death. Colorectal carcinomas in common with other cancer types such as cancer of the prostate and lung often produce their own growth factors and receptors. Activation of the receptor by the growth factor further stimulates the tumour's growth and spread throughout the body. The objective of this project is to deterrmine the potential roles of a growth factor termed bombesin. This peptide, now known as GRP ....Colorectal carcinoma (cancer of the large bowel) is the second most common cause of cancer death. Colorectal carcinomas in common with other cancer types such as cancer of the prostate and lung often produce their own growth factors and receptors. Activation of the receptor by the growth factor further stimulates the tumour's growth and spread throughout the body. The objective of this project is to deterrmine the potential roles of a growth factor termed bombesin. This peptide, now known as GRP in mammalian systems, is an established growth factor in certain lung cancers but little is known about its role in tumours of the large bowel. This project is based on our novel observation that the precursor of GRP (proGRP) previously thought to be inactive is in fact biologically active in stimulating the growth of colorectal carcinoma cells. We will determine which parts of the GRP precursor (proGRP) are bioactive, and test the effects of the bioactive regions on growth and cancer spread using a variety of colorectal cancer cell lines. We will also investigate the effects of the bioactive regions of proGRP on the development of colorectal cancer in three animal models, which represent different stages of the progression to invasive cancer. We will then compare the intracellular pathways by which proGRP and GRP communicate with the cell nucleus, and investigate the structure of the cell-surface receptor that binds the proGRP. Finally we will determine the types and amounts of proGRP derived peptides produced by CRC cell lines and by tumours obtained from patients with colorectal cancer. A successful outcome will result in the development of assays for the early diagnosis and monitoring of bowel cancer and the potential for novel treatments such as proGRP receptor antagonists and radioactive proGRP analogues for radiotherapy.Read moreRead less
My major goal for the past 20 years has been to understand how hormones such as gastrin stimulate the development of gastrointestinal cancer. One approach has been to define the intracellular signalling pathways by which gastrins enhance cell growth. Our discovery that iron is essential for the biological activity of gastrins may allow the development of novel therapies for colon cancer and iron overload.