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.
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
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.
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
PROTEIN TARGETS FOR THE STEROID RECEPTOR MODULATOR, CYCLOPHILIN 40
Funder
National Health and Medical Research Council
Funding Amount
$374,828.00
Summary
Steroids bind to specific receptor proteins in steroid responsive cells. These receptors are kept in a steroid-binding ready state by chaperone proteins which function to fold the receptors appropriately. The major chaperone protein is heat shock protein, hsp90. A second family of proteins called immunophilins, cooperate with hsp90 in receptor folding. These immunophilins can bind to immunosuppressant drugs, which may result in a change in receptor function. We have identified one of these immun ....Steroids bind to specific receptor proteins in steroid responsive cells. These receptors are kept in a steroid-binding ready state by chaperone proteins which function to fold the receptors appropriately. The major chaperone protein is heat shock protein, hsp90. A second family of proteins called immunophilins, cooperate with hsp90 in receptor folding. These immunophilins can bind to immunosuppressant drugs, which may result in a change in receptor function. We have identified one of these immunophilins as cyclophilin 40 ( CyP40), a protein that binds the immunosupressant drug, cyclosporin A. We have recently found that, in addition to binding to hsp90, CyP40 may bind to and regulate the function of other proteins which are important in how cells grow and die. The aims of this project are to study how CyP40 binds to hsp90 and to these other proteins and to determine the functional outcomes of these interactions.Read moreRead less