Viral Interference With Apoptosis: Defining The Mechanisms And Effects On Viral Pathogenesis
Funder
National Health and Medical Research Council
Funding Amount
$551,328.00
Summary
Apoptosis, or programmed cell death, is an orderly process whereby unwanted or damaged cells are removed from an organism. Deregulation of apoptosis has been implicated in the development of diseases such as cancer and autoimmunity. Therefore, a precise understanding of the mechanisms controlling the initiation of apoptosis has important clinical implications. In addition to removing unwanted cells, apoptosis functions as a defence mechanism to inhibit viral replication. Hence, in order to repli ....Apoptosis, or programmed cell death, is an orderly process whereby unwanted or damaged cells are removed from an organism. Deregulation of apoptosis has been implicated in the development of diseases such as cancer and autoimmunity. Therefore, a precise understanding of the mechanisms controlling the initiation of apoptosis has important clinical implications. In addition to removing unwanted cells, apoptosis functions as a defence mechanism to inhibit viral replication. Hence, in order to replicate efficiently viruses have evolved means to inhibit or interfere with apoptosis. The central aim of this work is to understand how two genes encoded by murine cytomegalovirus (MCMV) inhibit apoptosis and contribute to viral replication. MCMV is used as a model for human CMV (HCMV) infection. The majority of the human population is infected with HCMV which poses no risk to healthy individuals. However, reactivation of HCMV in people who are immunosuppressed such as transplant recipients or AIDS patiens is a significant cause of mortality. The MCMV infection model has provided important insights as to how the immune system controls infection and the mechanisms utilized by viruses to circumvent these processes. The proposed studies will improve our understanding of the processes that regulate viral replication. Understanding how viruses subvert host defence mechanisms will allow us to better understand their role in causing human disease, and thus, will provide key information for the design of improved anti-viral strategies. Importantly, the type of analyses proposed here will also contribute critical insights into the normal processes that control cell survival.Read moreRead less
Temporal And Spatial Regulation Of Caspases In Development And Metamorphosis
Funder
National Health and Medical Research Council
Funding Amount
$473,250.00
Summary
Cell death by a special process called apoptosis is a means of deleting unwanted and harmful cells from the body. Extensive apoptosis occurs during foetal development which is required to get rid of many excess cells produced during the growth of the embryo. Selective apoptosis is also essential for the formation of different tissues and organs in developing foetus. In the adult, apoptosis is required for proper functioning of the immune system, to remove virus infected and cancer cells and in g ....Cell death by a special process called apoptosis is a means of deleting unwanted and harmful cells from the body. Extensive apoptosis occurs during foetal development which is required to get rid of many excess cells produced during the growth of the embryo. Selective apoptosis is also essential for the formation of different tissues and organs in developing foetus. In the adult, apoptosis is required for proper functioning of the immune system, to remove virus infected and cancer cells and in general to maintain the correct number of cells in the body. As such, misregulated apoptosis is associated with the pathogenesis of a wide array of diseases such as autoimmune diseases, many forms of cancer and neurodegenerative disorders (such as Alzheimer's and Parkinson's diseases), heart disease, ischaemia and other conditions. To understand, manage and treat disorders that result from aberrant apoptosis, we need to know at molecular and cellular level, how apoptosis is brought about and how it is regulated. We have been studying these processes in detail for several years. Central to the apoptotic execution of cell death are a group of proteases that target many cellular proteins for specific cleavage. The activation of these proteases is the crucial step in the initiation of apoptosis and therefore each cell has developed complex ways to control this process. In the present proposal, we aim to study regulation of caspases that are involved in developmental apoptosis. Furthermore, we plan to identify proteins that are responsible for the regulation of caspase activation.Read moreRead less
Characterisation Of The Anti-apoptotic Function Of P-glycoprotein And Transcriptional Regulation Of The MDR1 Gene
Funder
National Health and Medical Research Council
Funding Amount
$324,150.00
Summary
The ability of tumor cells to survive treatment by chemotherapy is a major obstacle in curing patients with cancer. One mechanism by which cancer cells become multidrug resistant (MDR) is their acquired expression of a cell surface protein called P-glycoprotein (P-gp) that serves to extrude cytotoxic drugs out of the cancer cell via a pumping mechanism. Recently, we demonstrated, that in addition to its role in removing drugs from cells, P-gp can also protect cells against death induced by stimu ....The ability of tumor cells to survive treatment by chemotherapy is a major obstacle in curing patients with cancer. One mechanism by which cancer cells become multidrug resistant (MDR) is their acquired expression of a cell surface protein called P-glycoprotein (P-gp) that serves to extrude cytotoxic drugs out of the cancer cell via a pumping mechanism. Recently, we demonstrated, that in addition to its role in removing drugs from cells, P-gp can also protect cells against death induced by stimuli other than drugs where an efflux effect of P-gp would have no obvious benefit. This broader effect of P-gp to enhance cell survival may be explained by its ability to regulate the activity of key enzymes that exist within cells to induce cell suicide when appropriate. Some chemotherapeutic drugs activate these death enzymes (caspases) to kill target cells and it is therefore possible that P-gp affects the activity of anti-cancer drugs by both removing the drugs from the target cells and inhibiting the pathways through which the drugs can kill the cell. We are now determining how P-gp affects the activity of caspases. In addition, we have defined the manner by which P-gp expression is kept low in normal cells and is upregulated in many MDR tumor cells. It appears that the way the gene expressing P-gp (called MDR1) is packaged within chromosomes regulates gene expression levels. We are now identifying the proteins and complexes involved in regulating MDR1 expression to fully determine the molecular events that occur during the manifestation of a P-gp-expressing MDR tumor. Our new findings may lead to novel treatment options for patients that have MDR cancers and may provide insight into possible new ways to inhibit the formation of P-gp-expressing MDR tumors in the first place.Read moreRead less
Is The Tumour Suppressor Activity Of P53 Independent Of Its Transcriptional Role?
Funder
National Health and Medical Research Council
Funding Amount
$162,920.00
Summary
To become cancerous, a cell must avoid death. As such, cancer cells often contain defects in cell death pathways which render them resistant to pro-death stimuli, including many chemotherapeutic drugs. To design new and better cancer therapies, it is essential that we understand the critical molecular processes that control cell death. This will allow the development of more effective ways to either reset, or bypass, defects in cell death pathways which have contributed to cancer formation.
I am a molecular geneticist investigating the development of cancer, the mechanisms controlling apoptosis, and how impaired apoptosis contributes to tumorigenesis and the resistance of cancer cells to therapy.
Investigating Mitochondrial Outer Membrane Permeabilization During Programmed Cell Death
Funder
National Health and Medical Research Council
Funding Amount
$88,065.00
Summary
Cancer cells often contain defects which prevent their death. To kill cancer cells we must either reset or bypass these defects. Release of cytochrome c from mitochondria is a critical event in cell death and proteins that block this event render cells resistant to many cancer therapies. My research will determine how cytochrome c release occurs, how this event is regulated and how to kill cancer cells in which cytochrome c release is blocked.
I am a molecular biologist interested in understanding how cells are able to actively kill themselves, and how cells make the decision to live or die. Understanding how cells kill themselves will ultimately lead to better therapies designed to kill cancer