Impact Of Progesterone Receptor Subnuclear Localisation On Progesterone Action In Endocrine Target Cells
Funder
National Health and Medical Research Council
Funding Amount
$459,514.00
Summary
Breast cancer affects 10,000 Australian women annually and is a major cause of cancer death. The hormone progesterone, which is produced by the ovaries in women, is responsible for some aspects of the development of the normal breast in women and is also implicated in the development and response of breast and endometrial cancers. In normal cells progesterone acts via a specific protein (or receptor) in the nucleus, and we have shown that this protein accumulates into foci when it is active. We ....Breast cancer affects 10,000 Australian women annually and is a major cause of cancer death. The hormone progesterone, which is produced by the ovaries in women, is responsible for some aspects of the development of the normal breast in women and is also implicated in the development and response of breast and endometrial cancers. In normal cells progesterone acts via a specific protein (or receptor) in the nucleus, and we have shown that this protein accumulates into foci when it is active. We have noticed that in cancers, this accumulation is disrupted, and this is a bad sign for the cancer. As breast cancer develops, it causes many dramatic changes in the structure of cells of the breast, and particularly in the nucleus, which carries the genetic information that programs cancer cell behaviour. The nucleus normally is highly organised into compartments, which carry out different functions of the cell, such as duplication of the DNA, repair of DNA after damage, and switching on and off of particular genes important to the function of the cell. This organisation is altered dramatically in cancer cells, and it seems that this altered organisation is responsible for altered function. In this project we aim to work out what makes the receptor for progesterone form foci, how these foci are involved in the action of progesterone, and how the changed structure of the nucleus changes this process. This project will link the structure of the cell nucleus with the ability of progesterone to switch on or off particular genes, and this will provide the first signposts of how changes seen in cancer cell nuclei are reflected in changed hormonal signalling. Healthy women are regularly exposed to progestins in oral contraceptives and hormone replacement therapy. The known increased risk of breast cancer as a result of exposure to progestins creates an imperative to understand how progesterone may have aberrant effects. This project will address this important health issue.Read moreRead less
CHAPERONES IN BREAST CANCER AND ESTROGEN RECEPTOR FUNCTION
Funder
National Health and Medical Research Council
Funding Amount
$256,573.00
Summary
Resistance to hormone therapy in breast cancer is due to adaptations of estrogen signalling mechanisms that result in ERa activation causing growth. So, in the search for new treatments, we are looking for ways to remove ERa from the breast cancer cell. Our study addresses this major issue by focussing on Hsp90 molecular chaperone machinery that is essential for ERa function and in particular immunophilin 'helper' cochaperones that form part of receptor-Hsp90 complexes and fine-tune receptor res ....Resistance to hormone therapy in breast cancer is due to adaptations of estrogen signalling mechanisms that result in ERa activation causing growth. So, in the search for new treatments, we are looking for ways to remove ERa from the breast cancer cell. Our study addresses this major issue by focussing on Hsp90 molecular chaperone machinery that is essential for ERa function and in particular immunophilin 'helper' cochaperones that form part of receptor-Hsp90 complexes and fine-tune receptor responses to hormone. Through a novel mode of action, coumarin-based Hsp90 inhibitors disrupt Hsp90 dimerization causing receptor release and subsequent depletion. We will confirm this novel mechanism for new, high affinity Hsp90 inhibitors and determine which can best interfere with estrogen signalling, either alone or in combination with antiestrogen therapies in the treatment of hormone-dependent cancers. Our study has the potential to pin point the site of action of the immunophilins in ERa to a proline in a region critical for ligand-induced receptoractivation. We will determine the role of the immunophilins and this active-site proline residue in modulating receptor stability and function. Aberrant expression of receptor-associated immunophilins appears linked to endocrine resistance and metastasis in breast cancer. Our study will profile the expression of these chaperones in well defined breast cancer tissue microarrays, and has the potential to identify them as informative biomarkers in the treatment of the disease.Read moreRead less
The steroid hormone aldosterone controls salt balance and hence, blood pressure. It also has been shown to have a significant role in cardiac failure. Although drugs that block the aldosterone receptor are beneficial in the treatment of heart failure, they are limited by potassium retention in the kidney. In order to develop tissue-specific blockers of the aldosterone receptor, it is necessary to identify mechanisms by which the receptor can be activated and/or blocked in these tissues.
Progesterone Receptor Action In The Normal Human Breast
Funder
National Health and Medical Research Council
Funding Amount
$360,500.00
Summary
Breast cancer affects 10000 Australian women annually and is a major cause of cancer-related death. The hormone progesterone, which is produced by the ovaries in women, is responsible for many aspects of normal breast development and function. Progesterone is also a major component of hormone replacement therapy (HRT) and oral contraceptives (OCP), which are taken by millions of women worldwide. It has been established that the use of HRT and OCP containing progesterone-like hormones leads to in ....Breast cancer affects 10000 Australian women annually and is a major cause of cancer-related death. The hormone progesterone, which is produced by the ovaries in women, is responsible for many aspects of normal breast development and function. Progesterone is also a major component of hormone replacement therapy (HRT) and oral contraceptives (OCP), which are taken by millions of women worldwide. It has been established that the use of HRT and OCP containing progesterone-like hormones leads to increased breast cancer risk, yet the ways in which this happens are not known. Breast cancer is thought to begin early in a woman's life, with a number of genetic changes that accumulate over a period of many years; the majority of breast malignancies are not diagnosed until after the age of 50. However, there are recent indications that some areas of apparently normal breast have undergone a few genetic changes, even in women with no evidence of malignancy, but there is nothing known about how progesterone may affect these areas and possibly encourage breast cancer development. This project will firstly explore the influence of progesterone on the normal breast, to clarify how this hormone acts in normal cells. We will then investigate the involvement of progesterone in areas of normal breast that have undergone genetic alterations. This will determine whether one way in which progesterone may increase breast cancer risk is by affecting the behaviour of cells with genetic changes to make them more likely to develop further changes and subsequently progress to full cancer development. If women are to continue to derive the benefits of progesterone exposure, there is a compelling need to appreciate how progesterone acts in the normal breast and how it increases breast cancer risk. Achievement of the aims of this project will provide invaluable knowledge and greatly increase our understanding in this area.Read moreRead less
The Essential Role Of Androgen Receptor Signalling In Prostate Tumorigenesis
Funder
National Health and Medical Research Council
Funding Amount
$714,375.00
Summary
An urgent objective in prostate cancer clinical practice is to better predict disease course at diagnosis and to identify patients likely to develop metastatic (lethal) disease. We aim to identify clinically-relevant genes - gene pathways that are important in prostate cancer development and progression and which can be used to improve prediction of patient outcome. Prostate cancer management can be improved by tailoring treatments for individual patients.
NR4A Orphan Nuclear Receptor Signalling In Skeletal Muscle: Evidence For Crosstalk With The Beta-adrenergic Pathway.
Funder
National Health and Medical Research Council
Funding Amount
$323,749.00
Summary
The NR4A subgroup of are 'orphan' members of the nuclear hormone receptor (NR) superfamily (that are all implicated in human disease). NRs are hormone-dependent DNA binding proteins that translate nutritional and pathophysiological signals into gene regulation. The importance of this 'drugable' gene family in the context of promoting and maintaining human health is underscored by the diversity of medicinals associated with dysfunctional hormone signalling, in the context of inflammation, diabete ....The NR4A subgroup of are 'orphan' members of the nuclear hormone receptor (NR) superfamily (that are all implicated in human disease). NRs are hormone-dependent DNA binding proteins that translate nutritional and pathophysiological signals into gene regulation. The importance of this 'drugable' gene family in the context of promoting and maintaining human health is underscored by the diversity of medicinals associated with dysfunctional hormone signalling, in the context of inflammation, diabetes, dyslipidemia, and endocrine disorders (e.g ~15% of the top selling therapeutic compounds target NRs). The NR4A subgroup are stress response genes which are induced by a wide range of physiological stimuli and have been implicated in the response to energy excess (over-eating) and diet induced obesity. The NR4A subgroup are expressed in skeletal muscle, a major mass peripheral tissue that accounts for ~40% of the body mass and energy expenditure. This lean tissue is a major site of fat oxidation, insulin-stimulated glucose utilization and cholesterol metabolism. Therefore this tissue plays a notable role in insulin sensitivity, the blood lipid profile, and energy balance. Accordingly, muscle has a significant role in the progression of dyslipidemia, diabetes and obesity. Surprisingly, the function of the NR4A subgroup in skeletal muscle metabolism has not been examined. Nevertheless, given the data on NR4A mediated gene regulation, and the potential therapeutic utility for the treatment of metabolic disease, the contribution of skeletal muscle to NR4A action must be defined. Correspondingly, the objective of this proposal is to examine the role of the NR4A subgroup and is relevant to understanding the basis of dyslipidemia and obesity.Read moreRead less
Nuclear Receptor 4A3 Signalling In Skeletal Muscle
Funder
National Health and Medical Research Council
Funding Amount
$475,745.00
Summary
Nuclear receptors regulate hormonal control of reproduction, endocrine physiology, and metabolism, and are very important in human health. NR4A3 function in peripheral tissues remains illusive. However, it is expressed in skeletal muscle, a tissue that (i) modulates blood lipids, insulin sensitivity and energy balance, and (ii) has an imortant role in diabetes and obesity. Understanding NR4A3 function in metabolism provides a potential platform for therapeutic intervention.
ERRgamma And Skeletal Muscle: Insights Into Lipid Utilization And Catabolism
Funder
National Health and Medical Research Council
Funding Amount
$357,936.00
Summary
The significance of Nuclear hormone receptors (NRs) in disease is underscored by the range of pharmacopoeia for the treatment of NR-associated disorders (e.g 16% of the top 100 drugs target NRs). ERRgamma receptors are abundantly expressed in skeletal muscle, a major mass periperal tissue that acconts for ~40% of total body weight, and energy expenditure. Muscle is the major site of glucose metabolism and, fatty acid oxidation. Consequently, it has a significant role in insulin sensitivity, the ....The significance of Nuclear hormone receptors (NRs) in disease is underscored by the range of pharmacopoeia for the treatment of NR-associated disorders (e.g 16% of the top 100 drugs target NRs). ERRgamma receptors are abundantly expressed in skeletal muscle, a major mass periperal tissue that acconts for ~40% of total body weight, and energy expenditure. Muscle is the major site of glucose metabolism and, fatty acid oxidation. Consequently, it has a significant role in insulin sensitivity, the blood lipid profile, lipid metabolism and obesity. Understanding the functional role of the orphan ERR receptors in skeletal muscle in the context of inflammation, lipid and energy homeostasis is of paramount importance in further understanding the mechanistic basis of dyslipidemia, chronic inflammation, insulin sensitivity, diabetes and obesity. Identification of novel ERRgamma targets that regulate metabolism in a major mass peripheral tissue, and positively influence the risk factors for cardiovascular disease, provides platforms for potential therapeutic intervention. Cardiovascular disease is the foremost cause of global mortality, and was responsible for >15 million deaths in 2003.Read moreRead less
Genomic And Non-genomic Actions Of Androgens In Regulation Of Fat Mass And Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$395,421.00
Summary
Men have lower amounts of body fat than women, but are more likely to deposit fat around the stomach and abdominal region than women. This increased abdominal fat in men significantly increases the risk of developing type 2 diabetes and heart disease. The differences between men and women suggest that there is hormonal control of fat development; however, little is known regarding how male sex hormones, androgens, control these processes. We will investigate how androgens control fat formation, ....Men have lower amounts of body fat than women, but are more likely to deposit fat around the stomach and abdominal region than women. This increased abdominal fat in men significantly increases the risk of developing type 2 diabetes and heart disease. The differences between men and women suggest that there is hormonal control of fat development; however, little is known regarding how male sex hormones, androgens, control these processes. We will investigate how androgens control fat formation, and the response of fat and muscle tissue to glucose and insulin, using mutant mouse strains. These mouse strains have a mutation in the androgen receptor, a protein which acts as a key-lock mechanism to allow tissues to respond to androgens. This mutation stops the androgen receptor from functioning, so these mice can be used to determine the function of androgens acting through the androgen receptor. We will study three strains of mutant mice: (i) in which the androgen receptor is non-functional in all tissues of the body; (ii) in which the androgen receptor is non-functional only in fat tissue, but normal in all other tissues; and (iii) in which the androgen receptor is non-functional only in skeletal muscle, but is normal in all other tissues. The aim of our research is to determine the effect of the mutations in these three different mouse lines on paramateres including the amount of fat formed, the site of fat deposition, the levels of lipids and insulin in the blood and their response to glucose. The androgen receptor is a master switch that turns on or off other genes. Therefore, we also aim to identify which genes are controlled by the androgen receptor in fat and muscle. This research will identify how androgens control fat development and function, and will identify genes that mediate these actions in fat and muscle. This will provide potential molecules that could be used therapeutically to treat obesity and prevent type 2 diabetes and heart disease.Read moreRead less