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
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
Progesterone Signalling In Normal And Malignant Breast Relies On Chromosomal Positioning Of Progesterone Receptor
Funder
National Health and Medical Research Council
Funding Amount
$569,346.00
Summary
The cell nucleus carries genetic information that directs cell function. The nucleus is organised into compartments, which are altered in breast cancer, leading to altered function. The ovarian hormone progesterone acts via a receptor, which clumps into foci in the nucleus when active. In cancers, this clumping is disrupted. In this project we will work out how these foci control cell function, and how this leads to the specific functions of progesterone in normal breast and breast cancers.
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.
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 Influence Of Gender And Steroid Hormones On Cerebrovascular NADPH Oxidase During Health And Disease
Funder
National Health and Medical Research Council
Funding Amount
$390,974.00
Summary
My research addresses several major questions regarding the regulation of brain blood flow and mechanisms that may contribute to stroke. There is confusion as to whether giving menopausal women hormone replacement worsens the effect of having a stroke. I propose that female hormones may lower blood flow to the brain after menopause and therefore cause more damage to the brain after stroke.
Focimatrix Regulation Of Sex Steroid Hormones In The Ovary
Funder
National Health and Medical Research Council
Funding Amount
$291,309.00
Summary
Sex steroid hormones (e.g. oestrogen and testosterone), are important to male and female health. In the ovarian follicle I identified a novel form of extracellular matrix (focimatrix) which develops in the ovary before the synthetic enzymes needed for sex steroids are present. Using evidence from other tissues, I developed ideas on how this matrix regulates the enzymes for hormone synthesis. I will examine a mechanism by which focimatrix could directly affect steroid hormone production.
Dual Targeting Of The Androgen Receptor For Effective And Durable Control Of Lethal Prostate Cancer
Funder
National Health and Medical Research Council
Funding Amount
$946,177.00
Summary
Preventing binding of androgens to the androgen receptor is the mainstay treatment for advanced prostate cancer, but resistance inevitably develops and the disease becomes lethal. We will develop a new drug that targets a part of the androgen receptor unrelated to its androgen binding function to overcome resistance to current therapy. As this drug will be effective in all stages of prostate cancer, it has high potential to improve survival outcomes for men with prostate cancer.
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
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.