The Molecular And Cellular Mechanisms Responsible For The Skeletal Complications Associated With Multiple Myeloma.
Funder
National Health and Medical Research Council
Funding Amount
$212,036.00
Summary
Multiple myeloma is an incurable disease of the antibody-producing B cell. Patients with MM, nearly always present with bone pain and unexplained bone fractures. These fractures are caused by the cancerous MM B cells, which are found in large numbers in discrete pockets throughout the bone marrow, close to the inner bone surface. The way that the cancerous B cells cause the local bone lesions is thought to be through the heightened activation of recruitment of osteoclasts. Osteoclasts are cells ....Multiple myeloma is an incurable disease of the antibody-producing B cell. Patients with MM, nearly always present with bone pain and unexplained bone fractures. These fractures are caused by the cancerous MM B cells, which are found in large numbers in discrete pockets throughout the bone marrow, close to the inner bone surface. The way that the cancerous B cells cause the local bone lesions is thought to be through the heightened activation of recruitment of osteoclasts. Osteoclasts are cells which normally, in a controlled manner, resorb bone as part of the ongoing process of new bone formation. We propose that myeloma cells, which exhibit characteristics of osteoclasts, home to sites in the bone marrow and initiate this bone breakdown and furthermore secrete factors required for osteoclast maturation and activity. We believe that these molecules include the recently defined molecule, termed osteoclast differentiation factor, which is normally produced by bone-producing cells known as osteoblasts. Moreover, we feel that myeloma B cells alter the function of osteoblast cells, which results in a decrease in bone formation. Finally, we propose that this disease and its associated bone defects originate from changes in the expression of a number of genes. The results from theses studies should provide a greater understanding of the way in which this B cell cancer originates and how it causes bone defects. This will lead to the development of better treatments to improve the survival of patients with MM, and will lead to therapies to prevent the associated bone complications.Read moreRead less
The Role Of CXCL12 (SDF-1)/CXCR4 In Pathological Angiogenesis And Osteolytic Bone Disease In Multiple Myeloma
Funder
National Health and Medical Research Council
Funding Amount
$665,896.00
Summary
Multiple myeloma (MM) is the second most common haematological (or blood) cancer in western countries and is unique amongst blood cancers in its capacity to destroy the skeleton. MM is a cancer of plasma cells, which in their normal non-cancerous form, reside in lymph nodes and produce antibodies against infectious agents. When they become cancerous, they migrate or home to congenial sites within the bone marrow (BM). This directed movement or homing occurs under the influence of a chemokine mol ....Multiple myeloma (MM) is the second most common haematological (or blood) cancer in western countries and is unique amongst blood cancers in its capacity to destroy the skeleton. MM is a cancer of plasma cells, which in their normal non-cancerous form, reside in lymph nodes and produce antibodies against infectious agents. When they become cancerous, they migrate or home to congenial sites within the bone marrow (BM). This directed movement or homing occurs under the influence of a chemokine molecule called CXCL12 which acts as a calling card for plasma cells to leave the lymph node and migrate to the BM. Once within the BM, the cells rapidly grow in response to BM-derived growth factors. This rapid growth causes a depletion in oxygen availability within the tumour and it becomes hypoxic. In response to this hypoxia, the tumour expresses a gene called hypoxia-inducible factor-1 (HIF-1) which regulates the expression of many proteins, including the chemokine CXCL12. Our studies show that the abnormal expression of CXCL12 by the plasma cells acts to promote blood vessel formation within the tumour, which in turn leads to greater tumour growth. In addition, our studies suggest that abnormal CXCL12 expression also promotes the recruitment and activation of large numbers of osteoclast (OC) precursors form the peripheral blood. OC are cells which normally remove unwanted or damaged bone. This proposal will study the interplay between HIF and CXCL12 in the establishment and development of MM and the associated bone destruction.Read moreRead less
Molecular And Cellular Mechanisms Of Skeletal Disease Mediated By Plasma Cell Dyscrasias
Funder
National Health and Medical Research Council
Funding Amount
$432,750.00
Summary
Osteolytic and osteosclerotic lesions of bone are common sequelae of primary and secondary bone cancers, including cancers of hematological origin. There is now strong evidence that tumor cells perturb the local balance between bone resorption and formation, and in cases of osteolysis, cause increased osteoclast (OC)-mediated bone resorption without a matching amount of bone formation. This proposal arises from our extensive clinical and basic science experience with multiple myeloma (MM) in add ....Osteolytic and osteosclerotic lesions of bone are common sequelae of primary and secondary bone cancers, including cancers of hematological origin. There is now strong evidence that tumor cells perturb the local balance between bone resorption and formation, and in cases of osteolysis, cause increased osteoclast (OC)-mediated bone resorption without a matching amount of bone formation. This proposal arises from our extensive clinical and basic science experience with multiple myeloma (MM) in addition to other skeletal tumors, and our strong background in both OC and osteoblast biology. MM is a hematological malignancy characterised by plasma cell dyscrasia, which typically causes progressive and severe destruction of the skeleton, with accompanying bone pain, fracture and finally, hypercalcaemia of malignancy. Two related diseases, MGUS and POEMS, have been chosen for study because of their key similarities and differences with MM, and are likely to shed new light on the activities of MM in the bone. MGUS does not cause identifiable bone defects, whereas POEMS can give rise to both osteolytic and osteosclerotic lesions. Comparison of these conditions will uniquely enable us to examine why these seemingly related neoplasms are able to mediate disparate skeletal disease states. Primarily, and since there are few curative therapies for MM at present, our proposed studies are designed to identify targets for therapy that will treat the most serious manifestation of this disease, namely its destruction of bone tissue.Read moreRead less
This study aims to identify naturally occurring genetic variations between men which modify the impact of testosterone, the major male hormone, on men's health and medical care. This study will examine new factors which determine how much any particular man may gain benefit from testosterone exposure such as in muscle and bone development as well as suffer detrimental effects on cardiovascular and prostate diseases. This may clarify some new aspects of how men's health is determined as well as d ....This study aims to identify naturally occurring genetic variations between men which modify the impact of testosterone, the major male hormone, on men's health and medical care. This study will examine new factors which determine how much any particular man may gain benefit from testosterone exposure such as in muscle and bone development as well as suffer detrimental effects on cardiovascular and prostate diseases. This may clarify some new aspects of how men's health is determined as well as developing new, customized medical treatments for men.Read moreRead less
Osteoblast Control Of Mesenchymal Progenitor Cell Differentiation: The Role Of Glucocorticoids And Wnt Signalling.
Funder
National Health and Medical Research Council
Funding Amount
$443,131.00
Summary
Osteoporosis is an important and growing health issue. Reduced ability to make new bone is an important cause of osteoporosis. In this project we will study how the immature cells which eventually make bone are recruited and controlled. In particular, we will study how genes coding for important growth factors are regulated so that the proper signals are sent to young cells to induce them to become bone-making rather than fat-making cells.
The Physiological Relevance Of Calcitonin In Osteoclast Function
Funder
National Health and Medical Research Council
Funding Amount
$437,640.00
Summary
Throughout adult life, bone tissue is continuously remodelled. The two main processes involved in bone remodelling, are bone formation and bone breakdown. Bone formation is controlled by cells known as osteoblasts and bone breakdown is controlled by cells known as osteoclasts. Under normal circumstances these two processes are tightly coupled. Excessive breakdown of bone, causes these two processes to become unbalanced and results in bone loss. This is the basis of many bone diseases such as ost ....Throughout adult life, bone tissue is continuously remodelled. The two main processes involved in bone remodelling, are bone formation and bone breakdown. Bone formation is controlled by cells known as osteoblasts and bone breakdown is controlled by cells known as osteoclasts. Under normal circumstances these two processes are tightly coupled. Excessive breakdown of bone, causes these two processes to become unbalanced and results in bone loss. This is the basis of many bone diseases such as osteoporosis, a condition in which the bones become fragile and therefore more susceptible to fracture. 1 in 2 women and 1 in 5 men aged 70 years and older suffer from osteoporosis in Australia. Despite this, the mechanisms which control osteoclast breakdown of bone are not well understood. Our laboratory is interested in how hormones affect osteoclast action. We plan to examine the role of the hormone calcitonin, thought to be important inhibitor of osteoclastic bone breakdown. This will be achieved by studying transgenic mice in which the receptor for calcitonin is specifically removed from osteoclasts. This will allow us to precisely determine the role of calcitonin in osteoclast function. Current treatment for osteoporosis involves the administration of drugs which inhibit bone breakdown. This project will increase our understanding of how calcitonin acts to regulate the function of osteoclasts. We believe that this research is of great importance as osteoporosis is becoming more prevalent as the population ages.Read moreRead less
V-ATPases Subunit D2 Is Critical For Acdification And Bone Resorption.
Funder
National Health and Medical Research Council
Funding Amount
$531,264.00
Summary
Overproduction and excessive activity of osteoclasts underlines many lytic bone disorders such as osteoporosis, Paget's disease and tumor-induced bone loss. The vacuolar proton pump (V-ATPase) located on the plasma membrane of the osteoclast is critical for osteoclastic bone resorption and, therefore represents a potential molecular target for the discovery of novel bone anti-resorptive agents. The proposed project addresses the fundamental role of the V-ATPase in osteoclast differentiation, aci ....Overproduction and excessive activity of osteoclasts underlines many lytic bone disorders such as osteoporosis, Paget's disease and tumor-induced bone loss. The vacuolar proton pump (V-ATPase) located on the plasma membrane of the osteoclast is critical for osteoclastic bone resorption and, therefore represents a potential molecular target for the discovery of novel bone anti-resorptive agents. The proposed project addresses the fundamental role of the V-ATPase in osteoclast differentiation, acidification and bone resorption. Understanding the molecular and cellular mechanisms by which V-ATPases regulate osteoclast function and bone resorption will facilitate the development of novel and selective inhibitors for the treatment of lytic bone disordersRead moreRead less
GENETIC PREDICTION OF FRACTURE IN A RISK-STRATIFIED POPULATION
Funder
National Health and Medical Research Council
Funding Amount
$363,000.00
Summary
Osteoporosis is a condition characterised by excessive bone loss and impaired bone quality, which ultimately results in fracture with minimal trauma. Osteoporosis affects 27% of women and 11% of men aged 60 years or above in the community, and costs Australia around $7 billion each year. Individuals with low bone mineral density (BMD) have a significantly higher risk of fracture than those with normal BMD. In the long-term (14-year) Dubbo Osteoporosis Epidemiology Study, more than half of indivi ....Osteoporosis is a condition characterised by excessive bone loss and impaired bone quality, which ultimately results in fracture with minimal trauma. Osteoporosis affects 27% of women and 11% of men aged 60 years or above in the community, and costs Australia around $7 billion each year. Individuals with low bone mineral density (BMD) have a significantly higher risk of fracture than those with normal BMD. In the long-term (14-year) Dubbo Osteoporosis Epidemiology Study, more than half of individuals with osteoporosis (e.g., low BMD) did not sustain a fracture, while approximately 60% of fracture cases had BMD above the high risk levels. Thus, BMD alone is not a good discriminant of fracture versus non-fracture cases. It is widely known that the liability to fracture is determined in part by genes. Previous studies, including from our group, have suggested a number of candidate genes that are associated with fracture risk. The fundamental issue that this study is concerned is that how and whether genetic markers could be used to facilitate case finding. It is proposed that common variations of certain genes are associated with fracture risk independent of BMD. That is, they can identify individuals at relatively high and low fracture risk after stratification for BMD. Hence, some markers may identify those individuals likely (and unlikely) to fracture even with low (osteoporotic) BMD. Similarly, some, possibly the same, markers may identify individuals at high risk of fracture despite relatively good (ie non-osteoporotic) BMD. It is further proposed that no single gene will achieve this outcome, but rather a small set of such gene polymorphisms will provide clinically useful risk information. This effect is entirely analogous to the use of clinical risk indicators (eg, age, weight, sex, family history, etc) to assess the risk of future fracture.Read moreRead less
The Therapeutic Value Of Targeting Wnt Signalling For The Treatment Of Osteoarthritis
Funder
National Health and Medical Research Council
Funding Amount
$561,535.00
Summary
Osteoarthritis (OA) affects 1.62 million Australians and imposes a significant burden on healthcare. It is characterised by damage to joint cartilage, and increased bone formation with formation of bone spurs. Our studies will determine the importance of the Wnt signalling pathway in mediating OA joint degeneration and identify mechanisms that regulate the activation of this pathway in OA. This will inform the development of novel therapeutic strategies which could halt joint damage in OA.
We have found that leptin, a new hormone produced by fat cells which regulates appetite and metabolism, is a powerful inhibitor of osteoclast formation. Osteoclasts are large cells present in bone which are responsible for bone resorption and therefore these cells contribute to common bone conditions such as osteoporosis, Paget's disease and bone cancer. Osteoporosis causes a great deal of pain and disability and it alone costs the Australian taxpayers more than $400 million per year. Persons wh ....We have found that leptin, a new hormone produced by fat cells which regulates appetite and metabolism, is a powerful inhibitor of osteoclast formation. Osteoclasts are large cells present in bone which are responsible for bone resorption and therefore these cells contribute to common bone conditions such as osteoporosis, Paget's disease and bone cancer. Osteoporosis causes a great deal of pain and disability and it alone costs the Australian taxpayers more than $400 million per year. Persons who are overweight tend to have higher circulating blood levels of leptin and also tend to have denser bones, which suggests that there might be a relationship between blood leptin and bone density or strength. Furthermore, leptin is produced in the bone marrow which is where osteoclasts are produced. Osteoclasts are formed from white blood cells which are present in the bone marrow and the blood. Very recent discoveries have identified a family of new factors which play a key role in the formation of osteoclasts. One of these factors has been called osteoprotegerin and is an inhibitor of osteoclast formation. Mutant mice lacking osteoprotegerin have greatly increased numbers of osteoclasts and severe osteoporosis whereas mutants with too much osteoprotegerin have bones which are much denser than normal. The availability of these factors now allows the generation of human osteoclasts in the laboratory which enables the further study of how the process is regulated. We have found that leptin increases the amount of osteoprotegerin produced by white blood cells and we believe that this is the major way that leptin inhibits osteoclast generation. In this project, we intend to further investigate how and why leptin is able to influence the generation and function of osteoclasts as leptin may be a suitable treatment for osteoporosis and other bone diseases.Read moreRead less