The Role Of Ghrelin And Growth Hormone Releasing Hormone In The Autocrine Regulation Of Prostate Cancer Cell Growth
Funder
National Health and Medical Research Council
Funding Amount
$240,990.00
Summary
Insulin-like growth factor-I (IGF-I) is an important growth factor with a major role in the growth and development of many normal and tumour cells. Its production is controlled by growth hormone (GH), released from the pituitary gland at the base of the brain. GH releasing hormone (GHRH), a hormone released from higher centres in the brain, regulates the production of GH itself and now it is recognised that a second pathway, the ghrelin-GH secretagogue receptor (GHS-R) axis is also important in ....Insulin-like growth factor-I (IGF-I) is an important growth factor with a major role in the growth and development of many normal and tumour cells. Its production is controlled by growth hormone (GH), released from the pituitary gland at the base of the brain. GH releasing hormone (GHRH), a hormone released from higher centres in the brain, regulates the production of GH itself and now it is recognised that a second pathway, the ghrelin-GH secretagogue receptor (GHS-R) axis is also important in regulating GH release. There is growing evidence that the GHRH-GH-IGF axis has a significant role in prostate cancer, but little is known about how this happens. We also have evidence that the ghrelin-GHS-R axis is involved in prostate cancer, as prostate cancer cell lines produce both ghrelin and the receptor through which it acts. Our preliminary studies show that ghrelin enhances cell growth in these cells. GHRH blocking agents (antagonists) are potential treatments for prostate cancer, as they slow the growth of prostate tumours. How they act is unclear, but they might interfere with a locally active GHRH pathway in the prostate. This study aims to explore the role of ghrelin and GHRH in prostate cancer. Since there is an increase in the use of GHRH, GH and-or IGF-I and potentially ghrelin for the treatment of a variety of medical conditions, including some in the aging male, the need for a fuller understanding of the role of this axis in prostate cancer is increasingly important. Such information will lead to a deeper understanding of the actions of ghrelin and GHRH and provide potential opportunities for design of new therapies for prostate and other GH-IGF-responsive tumours.Read moreRead less
Androgen Receptor Signalling And Progression Of Prostate Cancer
Funder
National Health and Medical Research Council
Funding Amount
$462,750.00
Summary
Prostate cancer is a major health problem in Australia, being the second leading cause of cancer deaths in men. Although there have been improvements in the diagnosis and treatment of prostate cancer, there are no effective treatments for advanced (metastatic) disease that has spread to other parts of the body. Currently, the only therapy for advanced disease involves the reduction in circulating androgens such as testosterone by surgical or medical castration, i.e. androgen ablation. Because pr ....Prostate cancer is a major health problem in Australia, being the second leading cause of cancer deaths in men. Although there have been improvements in the diagnosis and treatment of prostate cancer, there are no effective treatments for advanced (metastatic) disease that has spread to other parts of the body. Currently, the only therapy for advanced disease involves the reduction in circulating androgens such as testosterone by surgical or medical castration, i.e. androgen ablation. Because prostate cells are dependent on testicular androgens for their survival, surgical or medical castration results in an initial tumour regression. However, tumours inevitably develop resistance to current forms of androgen ablation therapy. Inappropriate activation of androgen signalling by non-testicular androgens or other agents may stimulate tumour growth following androgen ablation. In this study, we aim to identify and characterise determinants of the specificity and sensitivity of activation of the androgen receptor, which is the primary mediator of androgen action. Current androgen ablation treatments for prostate cancer only target the availability of androgenic ligands. We propose that it is also necessary to target the androgen receptor itself, because it can be activated by ligands other than testicular androgens. Therefore, we will also evaluate a panel ofagents that target different aspects of the androgen signalling axis, combined with androgen ablation using a cyclical approach to prevent or delay disease progression.Read moreRead less
Regulation And Functional Roles Of ADAM 10 Protease In Prostate Cancer.
Funder
National Health and Medical Research Council
Funding Amount
$465,750.00
Summary
Prostate cancer is the second most common cause of cancer death among western males. Most deaths from prostate cancer are due to the development of secondary tumours (metastases) in other body organs. Metastasis involves actions of enzymes, (called metalloproteinases) which can break down the tissue structure surrounding tumour cells, and actions of a family of proteins (called integrins)that control how cells stick to each other or to other tissue components. Both these actions allow tumour cel ....Prostate cancer is the second most common cause of cancer death among western males. Most deaths from prostate cancer are due to the development of secondary tumours (metastases) in other body organs. Metastasis involves actions of enzymes, (called metalloproteinases) which can break down the tissue structure surrounding tumour cells, and actions of a family of proteins (called integrins)that control how cells stick to each other or to other tissue components. Both these actions allow tumour cells to break free from their original tissue positions, walk through surrounding tissue and deposit themselves at distant sites to form a secondary tumour. In this research we are looking at a protein, called ADAM-10, which belongs to a family of proteases, the ADAMs, which contain both A Disintegrin And Metalloprotease activity, hence their name. Our data suggest ADAM-10 is produced in large quantities by prostate cancer cells but can be differently located within these cells it sits on the outer membrane of normal or benign prostate glands but re-locates to the cell nucleus in high grade prostate cancer cells. We have also identified ADAM-10 protein in small membrane fragments that are commonly shed from prostate cancer cells. Preliminary evidence suggests that levels of ADAM-10 in each of these locations is regulated by growth factors and-or the male sex hormone, androgen, key hormones involved in prostate cancer growth and progression. We do not yet know what actions ADAM-10 has when it occurs in these different locations but believe the membrane form will be involved in metastasis, with the nuclear form being involved in regulating events within the nucleus, the control centre for the cell. This grant application aims to build on our novel observations and investigate the underlying mechanisms of ADAM-10 hormonal regulation and function. If proven, these issues may be important for the development, progression and future treatment of prostate cancer.Read moreRead less
Characterising The Beneficial Effects Of Estrogen On The Prostate Gland
Funder
National Health and Medical Research Council
Funding Amount
$594,722.00
Summary
Prostate cancer is hormonally regulated and currently managed by androgen ablation. This application seeks to study the potential benefits of estrogen action for the treatment of prostate disease, including PCa. We will show estrogen hormone action causes prostatic cell death, targeting the stem-progenitor cells so the treated prostatic tissue does not regenerate. This project will provide pre-clinical proof of the efficacy of estrogenic compounds as a potential therapy for prostate disease.
IMMUNOPHILINS IN STEROID RECEPTOR- AND TISSUE-SPECIFIC ACTIONS: IMPLICATIONS FOR TREATMENT OF STEROID-BASED DISEASE
Funder
National Health and Medical Research Council
Funding Amount
$480,211.00
Summary
To convert steroid hormone signals in the cell steroid receptors rely on Hsp90 molecular chaperone machinery that is essential for receptor function and in particular 'helper' cohaperones that form part of receptor- Hsp90 complexes and fine-tune receptor responses to hormone. The present study addresses the fundamental role of the receptor helper' chaperone cyclophilin 40. Our study may have important implications for the treatment of steroid-based disease.
Characterisation Of A Novel Prostate-expressed Kallikrein-like Protease And Its Target Proteins
Funder
National Health and Medical Research Council
Funding Amount
$724,544.00
Summary
Prostate disease is common in most men in later life and can affect their quality of life adversely. The primary conditions are benign prostatic hyperplasia or BPH and prostate cancer. Symptoms of BPH affect between 50-70% of men over the age of 50 and prostate cancer is now the most common internal cancer diagnosed in men. More importantly, prostate cancer is the second most common cause of cancer deaths. We don't yet fully understand exactly how these diseases occur but the male sex hormones o ....Prostate disease is common in most men in later life and can affect their quality of life adversely. The primary conditions are benign prostatic hyperplasia or BPH and prostate cancer. Symptoms of BPH affect between 50-70% of men over the age of 50 and prostate cancer is now the most common internal cancer diagnosed in men. More importantly, prostate cancer is the second most common cause of cancer deaths. We don't yet fully understand exactly how these diseases occur but the male sex hormones or androgens are known to play an important role. Prostate specific antigen or PSA has become widely accepted as a useful tool in helping to detect prostate cancer and then monitoring the disease. PSA, which is regulated by androgens, is an enzyme that either activates or breaks down many proteins that are important in both the normal function of the prostate and in the development of cancer. PSA belongs to a family of enzymes called the kallikreins. We have recently discovered a new member of this family that, like PSA, is also found in the prostate. We have called this new enzyme, K6, as it is the sixth member of this family to be identified. So , this project is about characterising this new K6 enzyme, finding out if it is also found in the prostates of men with BPH and prostate cancer, whether it is also regulated by androgens and what sort of proteins it may activate in these diseases. We will also compare these findings with what we know about PSA in these diseases. From these studies, we will not only understand more about this K6 enzyme and how it might be important in the prostate but also how it relates to PSA. These findings may ultimately lead to some new approaches in the detection and treatment for BPH and prostate cancer.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
Role Of The Growth Hormone Binding Protein As A Transcriptional Activator
Funder
National Health and Medical Research Council
Funding Amount
$387,226.00
Summary
Growth hormone is an important hormone therapeutic for treating dwarfism. Recently, many new therapeutic applications for growth hormone have been discovered, particularly in relation to its role as an anabolic agent. These include post surgery recovery, enhanced bone fracture healing, Crohns disease, dilated cardiomyopathy, infertility and of course, ageing. This proposal examines a novel way that GH could work, that is by sending the extracellular part of its receptor (GHBP) to the nucleus, wh ....Growth hormone is an important hormone therapeutic for treating dwarfism. Recently, many new therapeutic applications for growth hormone have been discovered, particularly in relation to its role as an anabolic agent. These include post surgery recovery, enhanced bone fracture healing, Crohns disease, dilated cardiomyopathy, infertility and of course, ageing. This proposal examines a novel way that GH could work, that is by sending the extracellular part of its receptor (GHBP) to the nucleus, where it can directly activate gene readout. This would have the effect of augmenting the normal action of GH to regulate gene readout. We have exciting preliminary data which makes us think this may be a new mechanism for hormone activation of genes. The level of GHBP in the nucleus is regulated, and if a defect in export of the GHBP occurred, this would lead to accumulation of nuclear GHBP and stimulate cell proliferation. This may be important in cancer cell proliferation, since we find nuclear GHBP in cancers.Read moreRead less
The Mechanism Of Growth Hormone Receptor Activation
Funder
National Health and Medical Research Council
Funding Amount
$679,500.00
Summary
Growth hormone GH excess or deficit results in considerably shortened lifespan. While cardiovascular disease is a major element in this mortality, GH status has also been linked to kidney disease and diabetic retinopathy. Importantly, GH produced locally in breast cells and prostate cells transform s these cells, creating cancers. We aim to define how GH activates its receptor, to facilitate a GH antagonist which results from understanding how GH activates its cell surface receptor.