Gene therapy is a novel form of medical treatment in which healthy genes are used to replace defective genes in cells. It is sobering to realise that in the next few years the whole human DNA sequence will be known. Consequently the already large list of genes which are known to cause disease will be greatly expanded through the application of molecular genetics. Surprisingly, however, treatments based on the correction of disease genes in the cells of a patient are not keeping up with expectati ....Gene therapy is a novel form of medical treatment in which healthy genes are used to replace defective genes in cells. It is sobering to realise that in the next few years the whole human DNA sequence will be known. Consequently the already large list of genes which are known to cause disease will be greatly expanded through the application of molecular genetics. Surprisingly, however, treatments based on the correction of disease genes in the cells of a patient are not keeping up with expectations. In attempting to achieve clinically relevant results, viruses (masters of forcing infected cells to do their bidding) have been harnessed to deliver healthy genes into diseased cells. The problem has been that the modified, safe viruses used clinically have not been efficient at achieving sustained production of healthy genes in sufficient numbers of cells. In the studies described , we will attack this problem using a number of different, but complementary approaches. Our main focus will be to facilitate efficient virus entry of appropriate target cells. We have recently been successful in cloning the receptors for two important viruses which can enter human cells. Identification of these receptors gives us clues to methods of improving virus entry. Now that we know the identity of these receptors, we can create tools to define the type of cells that these viruses can readily target.Read moreRead less
Use Of Retroviral Expression Libraries To Characterise Mechanisms Of Drug Resistance In Leukaemia.
Funder
National Health and Medical Research Council
Funding Amount
$362,545.00
Summary
At present, treatment of leukaemia is based either on established chemotherapeutic drug treatment or newly identified inhibitor drugs currently being tested as part of clinical trials. Both these treatments are known to induce or select for resistance to the drugs in some cases. Resistance usually reduces the success rate of any further treatment with the same or similar drugs. To discover possible ways of overcoming drug resistance it is important to understand the mechanisms that are responsib ....At present, treatment of leukaemia is based either on established chemotherapeutic drug treatment or newly identified inhibitor drugs currently being tested as part of clinical trials. Both these treatments are known to induce or select for resistance to the drugs in some cases. Resistance usually reduces the success rate of any further treatment with the same or similar drugs. To discover possible ways of overcoming drug resistance it is important to understand the mechanisms that are responsible. To date a number of mechanisms that cause resistance are known, but there are still unidentified mechanisms that are associated with drug resistance. The aim of our work is to use a new method to identify unknown drug resistance mechanisms in leukaemia. Once a mechanism is identified, we will determine its relevance in leukaemia by screening a number of patients that have shown resistance to treatment. If identified as a common mechanism of resistance in leukaemic patients, we will test possible agents able to prevent drug resistance that could be used in conjunction with drug during treatment, and to screen new drugs for susceptibility to resistance mechanisms. Diagnostic tests to detect the presence of the known resistance mechanisms prior to treatment could be used in selection of the most appropriate drug combinations for individual patients. Some of the known drug resistance mechanisms that occur in leukaemia are also operative in other forms of cancer and the project is of general relevance to cancer chemotherapy.Read moreRead less
Cell-targeted Gene Delivery Into Human Haematopoietic Stem Cells For The Treatment Of Thalassaemia
Funder
National Health and Medical Research Council
Funding Amount
$171,208.00
Summary
Thalassaemia is the most common inherited single gene disorder affecting haemoglobin synthesis in red blood cells. It mainly affects people of Mediterranean, Middle Eastern, African, South East Asian, Chinese, and Indian origin. However, large numbers of thalassaemia patients are found nowadays in Australia and other developed countries, due to large population movements in the twentieth century. Approximately 300,000 severely affected children are born each year with thalassaemia and various ot ....Thalassaemia is the most common inherited single gene disorder affecting haemoglobin synthesis in red blood cells. It mainly affects people of Mediterranean, Middle Eastern, African, South East Asian, Chinese, and Indian origin. However, large numbers of thalassaemia patients are found nowadays in Australia and other developed countries, due to large population movements in the twentieth century. Approximately 300,000 severely affected children are born each year with thalassaemia and various other abnormalities of haemoglobin synthesis. If untreated, most thalassaemia patients will die within the first few years of life. The vast majority of thalassaemia patients depend on regular blood transfusions every two to three weeks, and on nightly infusions of an iron chelator (a drug for removing excess iron from the blood). These procedures place considerable burden on thalassaemia patients, their families and society, and expose them to blood transmitted infections. The only curative treatment for thalassaemia is bone marrow transplantation from a matching donor. However, the vast majority of patients do not have matching donors and thus the only prospect for them to receive such therapy is to replace in their bone marrow cells a copy of the normal set of genes for the synthesis of haemoglobin. The studies in this proposal are therefore designed to test gene therapy protocols on bone marrow stem cells derived from thalassaemia patients. A normal set of globin genes will be delivered to the bone marrow stem cells via non-viral delivery systems and examined for function in an immunodeficient mouse strain that can accept human bone marrow. This research may enable bone marrow transplantation to be applied for the therapy of most patients with thalassaemia, while it may also have a major impact on therapeutic approaches for other haematological anomalies.Read moreRead less
Role Of Selectins And Their Receptors In The Regulation Of The Haemopoietic System
Funder
National Health and Medical Research Council
Funding Amount
$472,500.00
Summary
The production of blood cells occurs in the bone marrow. This process depends on the controlled proliferation and development of rare and multipotent precursors called haemopoietic stem cells, and involves a subtle balance between the positive regulation of proliferation and growth inhibition necessary to prevent blood cell overproduction and leukaemia. We have recently shown that two related proteins expressed at the surface of cells of the bone marrow vasculature negatively regulate blood cell ....The production of blood cells occurs in the bone marrow. This process depends on the controlled proliferation and development of rare and multipotent precursors called haemopoietic stem cells, and involves a subtle balance between the positive regulation of proliferation and growth inhibition necessary to prevent blood cell overproduction and leukaemia. We have recently shown that two related proteins expressed at the surface of cells of the bone marrow vasculature negatively regulate blood cell formation. These proteins, called P-selectin and E-selectin, are essential to regulate the migration of immune cells into lymphoid organs and inflamed tissues. We have found that these selectins also mediate the adhesion of haemopoietic stem cells in the bone marrow vasculature, inhibit their proliferation and kill some of their progeny. This project includes three specific aims to: 1) characterise the role of P-selectin and E-selectin in vivo in the regulation of blood cell formation, 2) understand the molecular mechanisms inside haemopoietic stem cells which are responsible for the growth inhibition and cell death in response to selectins, and 3) identify the receptors which are responsible for these effects of selectins on haematopoietic stem cells. These findings will give us a better understanding of how blood formation is regulated in vivo and how these interactions are perturbed during the emergence of leukaemia.Read moreRead less
Role Of Neutrophil Proteases In The Mobilisation Of Haemopoietic Progenitor Cells
Funder
National Health and Medical Research Council
Funding Amount
$318,279.00
Summary
Mobilisation is a procedure consisting in inducing the egress of blood forming cells (haemopoietic stem cells) from the bone marrow, where they normally reside, into the blood. The most common agent to induce mobilisation of haemopoietic stem cell is a cytokine called granulocyte - colony stimulating factor (G-CSF). In recent years, the number of transplantations performed with mobilised blood stem cells has exceeded those performed with bone marrow. Elements contributing to this success have be ....Mobilisation is a procedure consisting in inducing the egress of blood forming cells (haemopoietic stem cells) from the bone marrow, where they normally reside, into the blood. The most common agent to induce mobilisation of haemopoietic stem cell is a cytokine called granulocyte - colony stimulating factor (G-CSF). In recent years, the number of transplantations performed with mobilised blood stem cells has exceeded those performed with bone marrow. Elements contributing to this success have been the simplicity of the procedure (daily injections of a mobilising cytokines such as G-CSF), a more rapid recovery following high dose chemotherapy and transplantation, and lower costs. Despite its common use in clinics, the molecular mechanisms responsible for haemopoietic stem mobilisation following injection of cytokines are still unknown. A large body of experimental data demonstrate the critical role of adhesive interactions between blood forming cells and the bone marrow microenvironment These interactions control the lodgement of blood forming cells in the bone marrow, where they normally reside, and their egress into the blood during mobilisation. Experiments from this laboratory have shown that the mobilisation of blood forming cells that follows the administration of G-CSF, may be the consequence of the accumulation in the bone marrow of a class of leukocytes called neutrophils. These neutrophils subsequently release within the bone marrow a set of enzymes that specifically cleave a cell adhesion molecule expressed in the bone marrow, and therefore disrupt the adhesive interactions between the bone marrow and the blood forming cells resulting in their egress in the blood. This proposal aims to demonstrate this hypothesis and to provide tools to predict and improve the levels of mobilisation that can be achieved with healthy donors and cancer patients.Read moreRead less
The Role And Inheritance Of Constitutional Epimutations In Early-onset Colorectal Cancer.
Funder
National Health and Medical Research Council
Funding Amount
$347,551.00
Summary
Traditionally familial cancers are thought to be caused by spelling mistakes within the genetic code of cancer prevention genes. Our group has found that chemical attachments to one gene (MLH1) stops it working, even where there is no spelling mistake, and that those chemical changes can be inherited in families with bowel cancer. We will determine how frequently this type of defect occurs in bowel cancer patients, how and why it arises, and if other cancer genes are similarly affected.
Epimutations As Germ-line Defects In Hereditary Cancer Syndromes
Funder
National Health and Medical Research Council
Funding Amount
$385,925.00
Summary
Traditionally familial cancers were thought to be caused and inherited by spelling mistakes within the genetic code of cancer prevention genes. Our group has found that a 'chemical coat' around the MLH1 gene, causing it to be switched off, can also be inherited in some cases of bowel cancer, without any mistakes within the gene's code. We will determine if this 'coat' causes other types of cancer and if this runs in families. We also hope to find out how the coat is formed and may be reversed.
Mechanisms Underlying The Effects Of Retinoic Acid Receptor Gamma In Haemopoiesis And Bone Homeostasis
Funder
National Health and Medical Research Council
Funding Amount
$366,801.00
Summary
My recent studies have demonstrated that a model of vitamin A deficiency results in impaired blood cell production and contributes to a blood cell disorder that can progress to leukaemia. There are also reduced numbers of blood stem cells (which give rise to all blood cells) and bone (which helps to regulate blood cell production) in this mouse model. In these studies I seek to understand more on how vitamin A deficiency causes these defects, which may lead to better treatment of such diseases.
Characterization Of Haemopoietic Lineage Determining Genes
Funder
National Health and Medical Research Council
Funding Amount
$631,021.00
Summary
Haemopoiesis is the process by which blood cells develop from stem cells. This process is tightly regulated and is dependant upon the appropriate expression of genes at each developmental stage within various lineages. Our work focuses on two genes (Mlf1 and Hls5) that are involved in determining lineage commitment and affect the expression of key hemopoietic regulators. If these genes are aberrantly expressed leukemias and other blood disorders can develop.