The Role Of Ghrelin And Growth Hormone Releasing Hormone In The Autocrine Regulation Of Prostate Cancer Cell Growth
Funder
National Health and Medical Research Council
Funding Amount
$240,990.00
Summary
Insulin-like growth factor-I (IGF-I) is an important growth factor with a major role in the growth and development of many normal and tumour cells. Its production is controlled by growth hormone (GH), released from the pituitary gland at the base of the brain. GH releasing hormone (GHRH), a hormone released from higher centres in the brain, regulates the production of GH itself and now it is recognised that a second pathway, the ghrelin-GH secretagogue receptor (GHS-R) axis is also important in ....Insulin-like growth factor-I (IGF-I) is an important growth factor with a major role in the growth and development of many normal and tumour cells. Its production is controlled by growth hormone (GH), released from the pituitary gland at the base of the brain. GH releasing hormone (GHRH), a hormone released from higher centres in the brain, regulates the production of GH itself and now it is recognised that a second pathway, the ghrelin-GH secretagogue receptor (GHS-R) axis is also important in regulating GH release. There is growing evidence that the GHRH-GH-IGF axis has a significant role in prostate cancer, but little is known about how this happens. We also have evidence that the ghrelin-GHS-R axis is involved in prostate cancer, as prostate cancer cell lines produce both ghrelin and the receptor through which it acts. Our preliminary studies show that ghrelin enhances cell growth in these cells. GHRH blocking agents (antagonists) are potential treatments for prostate cancer, as they slow the growth of prostate tumours. How they act is unclear, but they might interfere with a locally active GHRH pathway in the prostate. This study aims to explore the role of ghrelin and GHRH in prostate cancer. Since there is an increase in the use of GHRH, GH and-or IGF-I and potentially ghrelin for the treatment of a variety of medical conditions, including some in the aging male, the need for a fuller understanding of the role of this axis in prostate cancer is increasingly important. Such information will lead to a deeper understanding of the actions of ghrelin and GHRH and provide potential opportunities for design of new therapies for prostate and other GH-IGF-responsive tumours.Read moreRead less
Steroid hormones, such as oestrogen and cortisol, act in the body by binding a family of proteins (nuclear receptors) that bind directly to the DNA to regulate genes. The mechanisms underlying this process are complex and involve recruitment of additional molecules or coactivators to improve efficiency. Recently a novel coactivator was identified termed SRA, which remarkably is never made into protein in cells, rather exerting its effects as a RNA. We have identified a novel family of proteins t ....Steroid hormones, such as oestrogen and cortisol, act in the body by binding a family of proteins (nuclear receptors) that bind directly to the DNA to regulate genes. The mechanisms underlying this process are complex and involve recruitment of additional molecules or coactivators to improve efficiency. Recently a novel coactivator was identified termed SRA, which remarkably is never made into protein in cells, rather exerting its effects as a RNA. We have identified a novel family of proteins that bind to SRA in cancer cells, and may well play a critical role in regulating how SRA modulates genes. This project seeks to understand how this family interacts with SRA, the functional effects on breast cancer cells, and the detailed 3-dimensional structure of the family members coupled with SRA. This work will provide novel insight into how SRA regulates steroid hormone action, and may create new potential avenues for developing therapeutics in breast cancer.Read moreRead less
The Mechanism Of Growth Hormone Receptor Activation
Funder
National Health and Medical Research Council
Funding Amount
$679,500.00
Summary
Growth hormone GH excess or deficit results in considerably shortened lifespan. While cardiovascular disease is a major element in this mortality, GH status has also been linked to kidney disease and diabetic retinopathy. Importantly, GH produced locally in breast cells and prostate cells transform s these cells, creating cancers. We aim to define how GH activates its receptor, to facilitate a GH antagonist which results from understanding how GH activates its cell surface receptor.
Progesterone Regulation Of Epithelial Cell Lineages In The Breast
Funder
National Health and Medical Research Council
Funding Amount
$534,186.00
Summary
The ovaries play a pivotal role in breast cancer in ways that are unknown. Progesterone increases breast cancer risk, and response to hormonal treatments is critically associated with tumour progesterone receptor content, but how it does this is unknown. We will pursue our findings that progesterone influences cell types in the breast similar to those that become cancerous. This will uncover critical vulnerabilities in breast cancer development and potential targets for prevention and treatment.
Role Of The Growth Hormone Binding Protein As A Transcriptional Activator
Funder
National Health and Medical Research Council
Funding Amount
$387,226.00
Summary
Growth hormone is an important hormone therapeutic for treating dwarfism. Recently, many new therapeutic applications for growth hormone have been discovered, particularly in relation to its role as an anabolic agent. These include post surgery recovery, enhanced bone fracture healing, Crohns disease, dilated cardiomyopathy, infertility and of course, ageing. This proposal examines a novel way that GH could work, that is by sending the extracellular part of its receptor (GHBP) to the nucleus, wh ....Growth hormone is an important hormone therapeutic for treating dwarfism. Recently, many new therapeutic applications for growth hormone have been discovered, particularly in relation to its role as an anabolic agent. These include post surgery recovery, enhanced bone fracture healing, Crohns disease, dilated cardiomyopathy, infertility and of course, ageing. This proposal examines a novel way that GH could work, that is by sending the extracellular part of its receptor (GHBP) to the nucleus, where it can directly activate gene readout. This would have the effect of augmenting the normal action of GH to regulate gene readout. We have exciting preliminary data which makes us think this may be a new mechanism for hormone activation of genes. The level of GHBP in the nucleus is regulated, and if a defect in export of the GHBP occurred, this would lead to accumulation of nuclear GHBP and stimulate cell proliferation. This may be important in cancer cell proliferation, since we find nuclear GHBP in cancers.Read moreRead less
Functional Role Of A Novel Coregulator In Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$563,146.00
Summary
Australia is facing a massive epidemic of diabetes and obesity (diabesity). These disorders afflict all age groups, including teenagers, and are a major burden to the health and wealth of Australia. The nuclear receptors and their coregulators are excellent targets for developing new therapeutics to combat these disorders. This grant will evaluate the functional role of SLIRP, a novel nuclear receptor coregulator, in metabolism and could provide new avenues for drug target development.
The Effect Of Ghrelin, Leptin And Orexins On The Function Of Pituitary Somatotropes In Rat, Mouse And Human.
Funder
National Health and Medical Research Council
Funding Amount
$447,000.00
Summary
Malnutrition such as obesity or wasting syndrome is accompanied by GH deficiency. Three newly discovered metabolic regulatory hormones, leptin from fat tissue, ghrelin from stomach and orexins from hypothalamus, play important roles in regulating appetite, energy expenditure, and adiposity. Receptors for three metabolic regulatory hormones are all present in pituitary GH secreting cells (somatotropes) and accumulated laboratory data indicate a modification of GH secretion by three hormones. Cont ....Malnutrition such as obesity or wasting syndrome is accompanied by GH deficiency. Three newly discovered metabolic regulatory hormones, leptin from fat tissue, ghrelin from stomach and orexins from hypothalamus, play important roles in regulating appetite, energy expenditure, and adiposity. Receptors for three metabolic regulatory hormones are all present in pituitary GH secreting cells (somatotropes) and accumulated laboratory data indicate a modification of GH secretion by three hormones. Contradictory results have however been reported. Mechanisms of action of these three hormones are not clear and the interrelationship between metabolic regulatory hormones and intrinsic GH regulatory system is unknown. We propose to clarify this issue by investigating the effect of in vivo treatment of mice and in vitro treatment of cultured pituitary cells with leptin, ghrelin, and orexins. GH secretion, GH and GH-regulatory hormones' receptor synthesis in pituitary somatotropes will be measured. We will also use GH-GFP transgenic mice, in which somatotropes are specifically marked with green fluorescent signal, to study morphological change of somatotropes in mouse pituitary glands after in vivo treatment. By completing this project, we will be able (1) to clarify the physiological role of metabolic regulatory hormones in control of GH levels and (2) to clarify the pathological role of metabolic regulatory hormones in GH deficiency occurred in malnutritional conditions.Read moreRead less
Modulation Of Cytoskeletal Structure By Progesterone Receptor Isoforms
Funder
National Health and Medical Research Council
Funding Amount
$337,650.00
Summary
Ovarian hormones are fundamental regulators of normal cell growth and differentiation, and crucial to the development and progression of breast cancer. We have recently shown that the ovarian hormone progesterone can influence the expression of proteins in the cell scaffolding, known as the cytoskeleton. The cytoskeleton is responsible for maintaining cell shape, and there is growing evidence that alterations in the cytoskeleton can actually cause normal cells to become cancerous. We have shown ....Ovarian hormones are fundamental regulators of normal cell growth and differentiation, and crucial to the development and progression of breast cancer. We have recently shown that the ovarian hormone progesterone can influence the expression of proteins in the cell scaffolding, known as the cytoskeleton. The cytoskeleton is responsible for maintaining cell shape, and there is growing evidence that alterations in the cytoskeleton can actually cause normal cells to become cancerous. We have shown that progesterone affects the levels of a cytoskeletal protein called tropomyosin, which plays a pivotal role in cell shape maintenance. We have hypothesised that this effect may be important in the cell shape changes in breast cancer that lead to metastasis. In this grant, we will investigate the role of the progesterone receptor in controlling the expression of the cytokeleton; we will investigate whether cell shape changes caused by progesterone cause more aggressive behaviour in breast cancer cells and we will determine whether there are changes in cytokeletal proteins in breast tumours. This will provide a rational basis for further studies aimed at delineating the significance of hormonal regulation of cell architecture.Read moreRead less