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
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
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.
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
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.
The applicant's research is aimed at delineating the molecular mechanisms of action of steroid hormones in the pathogenesis of breast and prostate cancer with the goal of developing new diagnostic, prognostic and therapeutic response parameters of clinica
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.
Much of our current knowledge on development of external genitalia (ExG), the penis and clitoris, comes from 20 &70 year-old studies (1); but with significant developments in contemporary imaging and new mouse models, we have new data. The overall goal of this project is to prove the hypothesis that penile and clitoral development is estrogen- (and androgen-) dependent and, to show that the administration of exogenous endocrine disrupting chemicals that alter the balance between estrogen and and ....Much of our current knowledge on development of external genitalia (ExG), the penis and clitoris, comes from 20 &70 year-old studies (1); but with significant developments in contemporary imaging and new mouse models, we have new data. The overall goal of this project is to prove the hypothesis that penile and clitoral development is estrogen- (and androgen-) dependent and, to show that the administration of exogenous endocrine disrupting chemicals that alter the balance between estrogen and androgen will disrupt ExG development.Read moreRead less
Programmed cell death (PCD), also known as apoptosis, plays a fundamental role in cell and tissue homeostasis and its misregulation is implicated in many human diseases. Many hormones control PCD but their mechanisms of action remain poorly understood. As hormones, in particular the steroid hormones, are directly linked to the pathogenesis of many forms of cancer, including breast, prostate and ovarian cancer, some of the most common malignancies afflicting the society, it is important to study ....Programmed cell death (PCD), also known as apoptosis, plays a fundamental role in cell and tissue homeostasis and its misregulation is implicated in many human diseases. Many hormones control PCD but their mechanisms of action remain poorly understood. As hormones, in particular the steroid hormones, are directly linked to the pathogenesis of many forms of cancer, including breast, prostate and ovarian cancer, some of the most common malignancies afflicting the society, it is important to study the mechanism of hormonal control of apoptosis in order to identify components of the regulatory apparatus. Identification of precise factors that regulate PCD will not only provide basic understanding of hormone-controlled PCD, but any novel factors involved in the control of cellular levels of death activators or death inhibitors are potential targets for anticancer drug development. This proposal is based on our ongoing studies, which combine the powerful biochemical and cellular approaches with the in vivo studies in vinegar fly (Drosophila) to address complex issues that are often difficult to pursue by the direct use of mammalian systems. We believe that the results from this study will provide novel insights into the mechanisms of hormone-regulated control of PCD and how these control mechanisms are disrupted under pathological conditions.Read moreRead less