Investigating Tumour Development And Metastasis Using A Novel Drosophila Cancer Model.
Funder
National Health and Medical Research Council
Funding Amount
$505,500.00
Summary
The majority of cancers are derived from epithelial cells. The primary cause of cancer related deaths is due to the ability of these epithelial cancer cells to migrate and invade other tissues within the body away from their primary tissue of origin (metastasise). This proposal seeks to understand the pathways that are important in regulating the processes of epithelial cell migration and invasion that are instrumental in promoting the metastatic spread of tumour cells. As controls usually opera ....The majority of cancers are derived from epithelial cells. The primary cause of cancer related deaths is due to the ability of these epithelial cancer cells to migrate and invade other tissues within the body away from their primary tissue of origin (metastasise). This proposal seeks to understand the pathways that are important in regulating the processes of epithelial cell migration and invasion that are instrumental in promoting the metastatic spread of tumour cells. As controls usually operate to induce cell death in any cell that attempts to break away and invade other tissues, this proposal also seeks to understand some of the pathways that are responsible for causing these cells to die. To carry out these investigations we have developed a novel Drosophila model of epithelial cancer development. We use this model because of the ease with which it is possible to carry out complex genetic analyses and so dissect the roles of the many different signalling pathways involved in these processes. The strength of the model is that it is dependent upon genetic alterations that are also implicated in the development and metastatic spread of many mammalian cancers, namely activating mutations in two genes, Ras and Notch. It is expected, therefore, to offer considerable insight into why these activated genes also cause the spread of cancer cells in humans.Read moreRead less
Characterisation Of Cooperation Between Cell Polarity Regulators And Oncogenes In Tumourigenesis Using Drosophila
Funder
National Health and Medical Research Council
Funding Amount
$304,773.00
Summary
Cancers affect 1-3 people at some stage during their lifetime and therefore is of major importance to medical science. Cancers arise through the accumulation of mutations that alter normal cell proliferation control, differentiation, cell death or cell movement. In addition, recent studies have shown that the tumour environment (the interaction between cells) can be a major factor in the development of the cancer. However, this is difficult to study in mammalian models. In this proposal we use t ....Cancers affect 1-3 people at some stage during their lifetime and therefore is of major importance to medical science. Cancers arise through the accumulation of mutations that alter normal cell proliferation control, differentiation, cell death or cell movement. In addition, recent studies have shown that the tumour environment (the interaction between cells) can be a major factor in the development of the cancer. However, this is difficult to study in mammalian models. In this proposal we use the genetically amenable, model system, the vinegar fly Drosophila, to investigate the development of tumours using defined mutations. To explore mechanisms of tumourigenesis in Drosophila, we are using a system where we can make patches (clones) of mutant tissue within the context of normal tissue, a system that more faithfully mimics the development of mammalian cancer. We have observed that certain genes required for cell shape, (cell polarity genes, such as scrib) are important in limiting the action of oncogenes (tumour- causing genes, such as activated alleles of Ras) in the development of tumours in Drosophila. Thus, mutants in cell polarity genes cooperate with oncogenic mutations to result in the generation of invasive tumours. In a genetic screen, we have identified further genes that act in a similar manner to cooperate with mutants in scrib or activated Ras. In this proposal we seek to characterise these genes in tumourigenesis and to explore their mechanism of action. The expected outcome of this project is to elucidate novel genes and mechanisms of tumourigenesis in the context of a whole organism. Due to the conservation of cell proliferation and signalling proteins, this proposal is relevant to understanding human cancer.Read moreRead less
Genetic Analysis Of Cell Death Pathways, Drug Resistance And Oncogenic Co-operativity In IL-3 Dependent Cell Lines
Funder
National Health and Medical Research Council
Funding Amount
$445,270.00
Summary
The ultimate fate of most of our cells is to die by committing suicide, because they are no longer required, are no longer functioning, or are potentially harmful. This normal physiological process is termed apoptosis . Inappropriate apoptosis can contribute to cell loss following heart attacks, stroke or neurodegenerative diseases, such as Alzheimer s or Parkinson s disease. Conversely, when cell death fails to occur, abnormal cells can accumulate and lead to cancer. In addition, because drugs ....The ultimate fate of most of our cells is to die by committing suicide, because they are no longer required, are no longer functioning, or are potentially harmful. This normal physiological process is termed apoptosis . Inappropriate apoptosis can contribute to cell loss following heart attacks, stroke or neurodegenerative diseases, such as Alzheimer s or Parkinson s disease. Conversely, when cell death fails to occur, abnormal cells can accumulate and lead to cancer. In addition, because drugs that are used to treat cancer may exert their effect by inducing apoptosis, a failure of this suicide response may cause resistance to chemotherapy. The genes of the apoptosis pathway function either to promote or inhibit cell death. We have found that some genes in the apoptosis pathway allow apoptosis to proceed rapidly, but do not decide the fate of the cell. Other genes are required for a cell to commit to die. If these genes are mutated then apoptosis does not occur and a functional cell may survive. The distinction between cells that decide fate and those that do not is crucial because it is only the genes that decide cell fate that can act as cancer genes, and are valid targets for therapy. We use a model in which apoptosis is caused by removal of a growth factor, using cell lines derived from mice that lack particular genes in the cell death pathway. These cells proliferate normally in the presence of growth factor, and allow us to determine the role of the genes when growth factor is withdrawn. Because these cells are sensitive to chemotherapeutic drugs, we can also determine the contribution these genes make to cancer drug sensitivity. Using this system, we have discovered that Puma, a gene known to be required for apoptosis in response to radiation, is also a critical activator of apoptosis following growth factor withdrawal. We will determine the manner in which Puma is regulated by growth factors, as well as identify and characterise other key components.Read moreRead less