Interactions Between IGFBP-3 And TGFbeta In The Inhibition Of Breast Cancer Cell Growth
Funder
National Health and Medical Research Council
Funding Amount
$662,970.00
Summary
A protein first identified by our research group, called insulin-like growth factor binding protein-3 or IGFBP-3, has been shown to be a potent inhibitor of the growth of cancer cells. High levels of IGFBP-3 in the bloodstream are associated with a decreased risk of several cancer types, including breast cancer. However, the way in which this protein prevents cancer cells from growing is poorly understood. This project will investigate an entirely novel idea, developed in our laboratory, that th ....A protein first identified by our research group, called insulin-like growth factor binding protein-3 or IGFBP-3, has been shown to be a potent inhibitor of the growth of cancer cells. High levels of IGFBP-3 in the bloodstream are associated with a decreased risk of several cancer types, including breast cancer. However, the way in which this protein prevents cancer cells from growing is poorly understood. This project will investigate an entirely novel idea, developed in our laboratory, that the actions of IGFBP-3 are intimately connected with the actions of another known cell growth inhibitor called transforming growth factor beta (TGFbeta). We have found that these two proteins initiate the same sequence of events leading to growth inhibition in breast cancer cells, and that a receptor protein required for TGFbeta activity is also needed for IGFBP-3 to be inhibitory. Our work has the potential to explain for the first time exactly how IGFBP-3 stops cancer cells from growing. This is important because it is an abundant protein in the body, and understanding how it acts may lead to the development of new approaches to cancer therapy that exploit our findings.Read moreRead less
Endocrine And Autocrine Regulation Of Breast Cancer Cell Growth By IGF Binding Protein-3 (IGFBP-3).
Funder
National Health and Medical Research Council
Funding Amount
$497,250.00
Summary
The insulin-like growth factor (IGF) system of growth factors and their regulatory proteins is essential for normal growth, but is also involved in a number of overgrowth disorders. Some clinical studies have shown that a high level of IGF-I in the blood increases the risk of breast cancer in some women, but if the protein which carries it in the circulation, IGFBP-3, is also high, the risk is reduced. It has therefore been suggested that IGFBP-3 may be useful in the treatment of breast cancer. ....The insulin-like growth factor (IGF) system of growth factors and their regulatory proteins is essential for normal growth, but is also involved in a number of overgrowth disorders. Some clinical studies have shown that a high level of IGF-I in the blood increases the risk of breast cancer in some women, but if the protein which carries it in the circulation, IGFBP-3, is also high, the risk is reduced. It has therefore been suggested that IGFBP-3 may be useful in the treatment of breast cancer. This is supported by laboratory studies showing that IGFBP-3 can inhibit cell division and stimulate cell death in many cell types, including breast cells. However, some cells are resistant to IGFBP-3 s inhibitory effects, and in some cases IGFBP-3 may stimulate cells to grow and divide. In fact, the amount of IGFBP-3 present in breast tumours is highest in the fastest growing, most malignant tumours, suggesting that IGFBP-3 may be stimulating their growth. Our laboratory data indicates that breast cancer cells which produce a high level of IGFBP-3 grow faster as tumours than cells which produce little or no IGFBP-3. We believe that this is because IGFBP-3 interacts with another hormone system which is involved in rapid tissue growth, the EGF system, and increases its ability to stimulate breast cells to divide. These observations raise a number of important questions: how does IGFBP-3 interact with the EGF system to stimulate tumour growth; does IGFBP-3 from the blood promote the growth of EGF-sensitive tumours; and can the interaction between IGFBP-3 and the EGF system be abolished, or switched from growth stimulatory to growth inhibitory, thus inhibiting tumour growth. Answering these questions will provide important new information regarding IGFBP-3 s stimulatory and inhibitory actions, and the role of endocrine IGFBP-3 in tumour growth, and have the potential to lead to the development of novel therapies involving IGFBP-3 for the treatment of overgrowth disorders.Read moreRead less
Epidermal Growth Control In Psoriasis And Normal Skin
Funder
National Health and Medical Research Council
Funding Amount
$451,980.00
Summary
Our skin protects us from damage, dehydration, infection and harmful UV radiation. At the same time, we expect it to remain healthy, smooth and looking good. How the skin, and more particularly its upper layer, the epidermis, adapts to all these requirements is a complex problem yet to be fully understood. This question forms the basis of our project proposal. The epidermis is a continuously self-renewing tissue, in which cells have an average life of 30 days before they are invisibly shed to th ....Our skin protects us from damage, dehydration, infection and harmful UV radiation. At the same time, we expect it to remain healthy, smooth and looking good. How the skin, and more particularly its upper layer, the epidermis, adapts to all these requirements is a complex problem yet to be fully understood. This question forms the basis of our project proposal. The epidermis is a continuously self-renewing tissue, in which cells have an average life of 30 days before they are invisibly shed to the outside. In normal states and when responding to injury or disease, this cell turnover speed can be finely tuned, for example accelerated in the case of a healing wound. In contrast, if damaged by the sun, epidermal cells undergo a form of cell suicide (apoptosis) to prevent tumours forming from cells with damaged genes. This changing turnover speed is controlled by a series of growth factors, or cytokines. Insulin-like growth factor-I (IGF-I) is a unique cytokine that can control both cell turnover rate, and cell death. We aim to uncover the complex biochemical interactions that allow the epidermal IGF-I system to achieve this seemingly contradictory task. This study is important because when the epidermis loses the ability to finely tune its turnover speed, ulcers, sun damage, the common skin disorder psoriasis, or worse still, skin tumours, arise. This project explores ways of manipulating the IGF-I system to prevent this, and builds on some technology developed by the research group that has already proven effective in the control of psoriasis. The project also promises to discover undiscovered growth regulators that could be used in new gene therapies for skin overgrowth diseases.Read moreRead less
Determinants Of Insulin-like Growth Factor (IGF) Binding And Biological Actions Of IGF Binding Protein-6
Funder
National Health and Medical Research Council
Funding Amount
$399,750.00
Summary
Proteins are complex structures usually consisting of a number of distinct regions. Each of these regions may serve different roles. Insulin-like growth factors (IGFs) are important proteins involved in regulating the growth and other properties of cells. The actions of IGFs are in turn regulated by a family of binding proteins (IGFBPs). The aim of this project is to determine the range of actions of one of these IGFBPs and which parts of this IGFBP are involved in these actions. This may lead t ....Proteins are complex structures usually consisting of a number of distinct regions. Each of these regions may serve different roles. Insulin-like growth factors (IGFs) are important proteins involved in regulating the growth and other properties of cells. The actions of IGFs are in turn regulated by a family of binding proteins (IGFBPs). The aim of this project is to determine the range of actions of one of these IGFBPs and which parts of this IGFBP are involved in these actions. This may lead to new treatments for diseases in which cell growth is disturbed e.g. cancer and diabetes.Read moreRead less
Role Of IGF Binding Protein-3 (IGFBP-3) And IGFBP-5 As Modulators Of Nuclear Hormone Signalling
Funder
National Health and Medical Research Council
Funding Amount
$465,750.00
Summary
The insulin-like growth factors are small proteins involved in the growth of most tissues. Their actions are regulated by binding to larger proteins (known as IGFBPs) in the bloodstream and outside the cell. However, some IGFBPs are also found inside cells, where they seem to carry out other functions. We believe that two of these binding proteins, IGFBP-3 and IGFBP-5, change the way cells respond to vitamin A and vitamin D. These two vitamins are important in cell growth and in the way certain ....The insulin-like growth factors are small proteins involved in the growth of most tissues. Their actions are regulated by binding to larger proteins (known as IGFBPs) in the bloodstream and outside the cell. However, some IGFBPs are also found inside cells, where they seem to carry out other functions. We believe that two of these binding proteins, IGFBP-3 and IGFBP-5, change the way cells respond to vitamin A and vitamin D. These two vitamins are important in cell growth and in the way certain cells perform specialised functions. In test-tube experiments, IGFBP-3 and IGFBP-5 interact directly with the receptors that regulate the effects of these hormones. If the same thing happens inside the cell, IGFBP-3 and IGFBP-5 could change the way these receptors respond to signals from outside the cell. We will investigate what effect these IGFBPs have in living cells and in whole animals and how this may relate to human disease. If we are able to understand how IGFBP-3 and IGFBP-5 affect the way cells respond to vitamin A and D, then we may be able to develop new ways to treat certain human diseases.Read moreRead less
Pathways Involved In The Insulin-like Growth Factor (IGF)-independent Actions Of IGF Binding Protein-6
Funder
National Health and Medical Research Council
Funding Amount
$550,725.00
Summary
Insulin-like growth factors (IGFs) are important proteins that regulate growth. When not regulated properly, diseases such as cancer can occur. A family of IGF binding proteins regulates IGFs. IGFBPs may inhibit IGFs and we have shown that one of them, IGFBP-6, decreases growth of some experimental cancers. As well as regulating IGFs, some IGFBPs alter cell behaviour independently of IGFs, and we found that IGFBP-6 stimulates cell movement in this way. We will now determine how this happens.
Insulin-like Growth Factor (IGF)-II Binding Specificity Of IGF Binding Protein-6: Structural And Functional Studies.
Funder
National Health and Medical Research Council
Funding Amount
$265,630.00
Summary
Insulin-like growth factor II (IGF-II) is a protein which is involved in normal growth. However, in some circumstances it may also stimulate cancer growth. IGF binding protein-6 (IGFBP-6) binds to IGF-II and stops its activity. One of the major challenges of modern biology is understanding why some proteins bind to other proteins. Proteins fold in various ways and have specific three-dimensional structures. Two proteins which bind strongly to each other have structures which fit each other like ....Insulin-like growth factor II (IGF-II) is a protein which is involved in normal growth. However, in some circumstances it may also stimulate cancer growth. IGF binding protein-6 (IGFBP-6) binds to IGF-II and stops its activity. One of the major challenges of modern biology is understanding why some proteins bind to other proteins. Proteins fold in various ways and have specific three-dimensional structures. Two proteins which bind strongly to each other have structures which fit each other like a 'lock and key'. The aim of this project is to understand how IGFBP-6 binds to IGF-II by looking at its three-dimensional structure. Using this information, it may be possible to develop new treatments which can inhibit IGF-II activity and therefore may be useful in the treatment of some cancers.Read moreRead less
Insulin-like Growth Factor Binding Protein-3 (IGFBP-3) Sensitivity And Signalling In Breast Cancer
Funder
National Health and Medical Research Council
Funding Amount
$414,343.00
Summary
The growth of all tissues in the body depends on many growth factors, hormones and other proteins which work together to control cell division. Some of these factors stimulate the division of the cells which make up the body tissues, and some inhibit it, so that a balance of these stimulators and inhibitors ensures that tissues do not grow too fast, or too large. The development of breast cancer and the growth of breast tumours is thought to be due to uncontrolled or faulty actions of the protei ....The growth of all tissues in the body depends on many growth factors, hormones and other proteins which work together to control cell division. Some of these factors stimulate the division of the cells which make up the body tissues, and some inhibit it, so that a balance of these stimulators and inhibitors ensures that tissues do not grow too fast, or too large. The development of breast cancer and the growth of breast tumours is thought to be due to uncontrolled or faulty actions of the proteins and hormones which regulate the way breast cells multiply. One protein which normally regulates the division of breast cells is IGFBP-3. We have found that in some breast cancer cells, IGFBP-3 is no longer able to inhibit cell division, and this may lead to tumour growth and invasion of other tissues. We are interested in finding out how IGFBP-3 normally controls breast cell proliferation, and why some breast cancers are resistant to IGFBP-3. To do this, we will use normal breast cells in culture to examine how IGFBP-3 interacts with other cellular factors to prevent cell division. We will then look at whether the breast cancer cells have changed so that they are no longer able to recognise IGFBP-3 as an inhibitory protein. This may be because of changes in the way IGFBP-3 binds to the breast cancer cell, or because of changes in the way it interacts with other proteins in the cell. Because IGFBP-3 is made by normal and breast cancer cells, we will also study whether the IGFBP-3 being made by breast cancer cells is normal, or if it changed in some way that makes it inactive. By understanding why some breast cancers are not inhibited by IGFBP-3, we will be able to design new and better methods of preventing, detecting and treating the growth of all breast tumours.Read moreRead less
Regulation And Effect Of The Growth Hormone, IGF-I, And IGF-Binding Protein Response To Acute Exercise
Funder
National Health and Medical Research Council
Funding Amount
$367,197.00
Summary
The body's ability to respond to physiological stress is vital to survival. This series of studies aims to examine the hormonal responses to physical exercise. In studies recently completed to determine how to detect Growth Hormone (GH) abuse in the Olympics, we have discovered a new system of hormones that respond to exercise. These Insulin-like Growth Factors (IGF) and their IGF-Binding Proteins (IGF-BP) are normally controlled by GH. The IGF-IGF-BP system normally acts to control of many cell ....The body's ability to respond to physiological stress is vital to survival. This series of studies aims to examine the hormonal responses to physical exercise. In studies recently completed to determine how to detect Growth Hormone (GH) abuse in the Olympics, we have discovered a new system of hormones that respond to exercise. These Insulin-like Growth Factors (IGF) and their IGF-Binding Proteins (IGF-BP) are normally controlled by GH. The IGF-IGF-BP system normally acts to control of many cellular and organ functions in many different tissues of the body. For example they stimulate protein accumulation and muscle growth, and have actions to control blood glucose in conditions like diabetes. Little is known about what regulates the production of the IGF and IGF-BPs in response to physical exercise. We aim to examine whether GH, either as an acute pulse as occurs naturally, or a direct effect of exercise that is not GH-mediated, is responsible for the increase in IGF and IGFBPs. This may uncover a new means of controlling this powerful hormonal system. In addition, we will examine whether GH or IGF-I, alone and together, influence the body's ability to respond to the stress of exercise (e.g., controlling fuel use, cardiovascular and kidney responses). Such information will allow greater understanding of this important hormonal system, so that in novel therapies may be developed for conditions such as normal ageing, the wasting states that accompany severe surgical or infectious stress, or conditions with abnormal blood glucose regulation such as diabetes. In addition, this information will permit greater sophistication in the detection of GH and related compounds in elite athletes. Unfortunately, GH is also being abused by non-elite athletes and high-school children. We believe our efforts will asist in the detection and prevention of these more general societal health issues.Read moreRead less