There is an ongoing need for the development of new anticancer drugs, particularly those directed against solid tumours. In the past plants have been an extremely valuable source of anticancer agents, including the world s best selling anticancer drug, Taxol, isolated from the Pacific Yew tree. However, such molecules are typically complex and often very expensive to manufacture or extract from natural sources. So far very little attention has been paid to protein-based molecules from plants as ....There is an ongoing need for the development of new anticancer drugs, particularly those directed against solid tumours. In the past plants have been an extremely valuable source of anticancer agents, including the world s best selling anticancer drug, Taxol, isolated from the Pacific Yew tree. However, such molecules are typically complex and often very expensive to manufacture or extract from natural sources. So far very little attention has been paid to protein-based molecules from plants as potential anticancer agents because pharmaceutical companies have focused on organic molecules. In principle protein-based molecules could be produced much more cheaply and thus made available more widely to patients than existing drugs. All that is required are the lead molecules, or proteins that display sufficient anticancer activity to be used as the basis for further optimization. We have discovered a family of plant proteins called the cyclotides that have recently been shown to have considerable promise as anticancer agents. In the current project we will use synthetic chemistry to modify selected amino acids on the surface of this new family of proteins to determine which parts of the molecules are responsible for their activity. We will use this information to design improved analogues. The project is a collaboration between researchers at the Institute for Molecular Bioscience, University of Queensland, who have expertise in the required peptide chemistry and researchers and clinicians at Uppsala University, Sweden who have a range of assays and clinical expertise to test the new molecules. Both groups have been centrally involved in the discovery of the cyclotide family of plant proteins and are committed to developing them as exciting new anticancer agents.Read moreRead less
REGULATION OF GLUCOCORTICOID SENSITIVITY BY ANNEXIN-1
Funder
National Health and Medical Research Council
Funding Amount
$533,828.00
Summary
Steroids like prednisolone or cortisone are very effective at reducing inflammation in diseases like rheumatoid arthritis and are particularly known to decrease substances involved in inflammation. Almost 70% of patients with rheumatoid arthritis are treated more or less continuously with steroids. Steroid resistance (need for higher doses) or changes in steroid-sensitivity has been widely recognized in asthma, inflammatory bowel disease, and rheumatoid arthritis. Many new drug therapies however ....Steroids like prednisolone or cortisone are very effective at reducing inflammation in diseases like rheumatoid arthritis and are particularly known to decrease substances involved in inflammation. Almost 70% of patients with rheumatoid arthritis are treated more or less continuously with steroids. Steroid resistance (need for higher doses) or changes in steroid-sensitivity has been widely recognized in asthma, inflammatory bowel disease, and rheumatoid arthritis. Many new drug therapies however have the aim of keeping cortisone use to a minimum because of undesirable side effects like osteoporosis. Annexin-1 is an anti-inflammatory substance important in arthritis development which is also known to mediate many of the actions of steroids. However, the possible contribution of annexin-1 to mediate the effect of steroids in the regulation of these substances has not been examined. Moreover, how annexin-1 turns genes on is not known. Our studies will therefore reveal whether the absence of annexin-1 will increase inflammatory substances turn genes, and secondly, by determining the possible substances regulated by annexin-1 if the treatment with steroids are less effective in the absence of annexin-1. If annexin-1 is found either to increase anti-inflammatory substances or to mediate the effect of therapeutic steroids, its capacity to be involved in the beneficial effect of steroids may have an important impact in treatment of arthritis and other inflammatory diseases. If annexin-1 functionally acts as steroids, the reduction or discontinuation of steroid use will be possible.Read moreRead less
Molecular Targeting To Telomerase And Cancer Cell Immortality By A Novel Inhibitor
Funder
National Health and Medical Research Council
Funding Amount
$430,812.00
Summary
Infinite growth of cancer cells is a hallmark of cancer. Telomerase is required for cancer cell immortality. Inhibition of telomerase may thus offer an opportunity to stop cancer cells. We have identified an inhibitor of telomerase. This project will study the mechanisms of action of the novel inhibitor, investigating how to control cancer cell immortality as a baseline for more applied anti-cancer therapeutic studies.
Potential Anti-tumour Agents: Iron Chelators Of The Pyridoxal Isonicotinoyl Hydrazone Class
Funder
National Health and Medical Research Council
Funding Amount
$472,770.00
Summary
Iron (Fe) is essential for proliferation. Generally, cancer cells have a high Fe requirement due to their rapid rate of proliferation making them very susceptible to iron chelators which deplete cells of Fe. The potential of this therapy has been confirmed by the entrance of the chelator, Triapine (Vion Pharmaceuticals), into clinical trials. Further, a wide variety of studies including clinical trials have shown that the clinically used Fe chelator, desferrioxamine (DFO), can have potent anti-t ....Iron (Fe) is essential for proliferation. Generally, cancer cells have a high Fe requirement due to their rapid rate of proliferation making them very susceptible to iron chelators which deplete cells of Fe. The potential of this therapy has been confirmed by the entrance of the chelator, Triapine (Vion Pharmaceuticals), into clinical trials. Further, a wide variety of studies including clinical trials have shown that the clinically used Fe chelator, desferrioxamine (DFO), can have potent anti-tumour activity. Indeed, in an important clinical trial (Cancer Res 1990;50:4929), a marked decrease in tumour burden was observed while there was no significant side effects, demonstrating an appreciable therapeutic index. However, DFO suffers serious problems, including that it requires long infusions and does not readily permeate cells. Considering this, during the current NHMRC grant, we developed a novel group of chelators that show far greater activity than DFO and Triapine at inhibiting cancer growth in vitro and in vivo (Richardson BLOOD 2004;104:1450). These studies have been published in high quality journals such as BLOOD and Clin Cancer Res (Richardson 1995, 1997, 1999, 2001, 2002, 2004a,b,c) Recently, a potent metastasis suppressor gene, known as differentiation related gene-1 (Drg-1), has been identified. Up-regulation of this molecule plays an important role in inhibiting the growth of primary cancers and their metastatic spread. Importantly, we have recently shown that our new chelators markedly up-regulate the expression of Drg-1 in cancer cells and at the same time markedly and selectively inhibit the growth of these cells (Richardson BLOOD 2004;104:2967). Our hypothesis is the marked increase in Drg-1 expression after treatment with chelators could inhibit cancer cell growth and metastasis. Studies in this NHMRC grant renewal will lead to the development of new therapies and a greater understanding of cancer metastasis and biology.Read moreRead less
Modulating Interactions Between TNFalpha And IGF-1 Signaling Pathways To Reduce Necrosis Of Dystrophic Muscle
Funder
National Health and Medical Research Council
Funding Amount
$476,515.00
Summary
Duchene Muscular Dystrophy (DMD) is a lethal childhood disease that affects mainly boys. These experiments will test new highly specific anti-inflammatory drugs for the potential clinical treatment of muscular dystrophies, using the mdx mouse model of human DMD. It is essential that the benefits of such anti-inflammatory drugs are fully evaluated in long term studies in mice. Two of these drugs (Enbrel and Remicade) are already in wide clinical use for inflammatory disorders and present attracti ....Duchene Muscular Dystrophy (DMD) is a lethal childhood disease that affects mainly boys. These experiments will test new highly specific anti-inflammatory drugs for the potential clinical treatment of muscular dystrophies, using the mdx mouse model of human DMD. It is essential that the benefits of such anti-inflammatory drugs are fully evaluated in long term studies in mice. Two of these drugs (Enbrel and Remicade) are already in wide clinical use for inflammatory disorders and present attractive options for treatment of DMD patients due to their high specificity of action and relatively few side effects. We have shown that both of these drugs have a striking protective effect and reduce necrosis of dystrophic muscle in the mdx mouse. The benefits of these drugs (and the mouse equivalent cVIq) is due to blocking the action of the key pro-inflammatory cytokine Tumour Necrosis Factor-alpha (TNFa). However, the precise mechanism by which high levels of TNFa increase necrosis of dystrophic muscle is not clear. There are many possible pathways. Identifying which is the key pathway(s), is of central importance to design and target new drugs to treat such lethal muscle diseases. Such modulation of signalling is a major therapeutic goal. To determine which mechanism of TNFa action is responsible for muscle necrosis, experiments will investigate several signalling pathways using specific inhibitors: the drug Pifithrin to inhibit p53; soluble RAGE to block RAGE (Receptor for Advanced Glycation Endproducts); and specific inhibitory peptides to block JNK (c-Jun N-terminal kinase). The application of these inhibitors (drugs), in mice, as future therapies for muscle diseases is novel. These studies will provide much new information on TNFa related signalling that is highly relevant to the potential treatment of many diseases, including muscle wasting that is a major problem in the ageing population and in disuse atrophy and cachexia.Read moreRead less
Iron is essential for the growth of all cells. Generally, cancer cells have a high iron requirement due to their rapid rate of proliferation. This makes them susceptible to the action of drugs called iron chelators that deplete cell iron. A wide variety of studies, including clinical trials in leukemia and neuroblastoma patients, have shown that the clinically used chelator, desferrioxamine (DFO), can have potent anti-tumour activity. Indeed, in an important clinical trial, a marked decrease in ....Iron is essential for the growth of all cells. Generally, cancer cells have a high iron requirement due to their rapid rate of proliferation. This makes them susceptible to the action of drugs called iron chelators that deplete cell iron. A wide variety of studies, including clinical trials in leukemia and neuroblastoma patients, have shown that the clinically used chelator, desferrioxamine (DFO), can have potent anti-tumour activity. Indeed, in an important clinical trial, a marked decrease in tumour burden was observed while there were no significant side effects, demonstrating an appreciable therapeutic index. However, DFO suffers from serious problems, including that it requires long infusions and does not readily penetrate cells. Further, in some cancer patients, DFO has shown little activity. Considering these results, we have developed a new group of chelators that show far greater activity than DFO at inhibiting cancer cell growth. These studies have been published in high quality journals such as BLOOD (Richardson et al. 1995, 1997, 1999) and form the basis for the current study. In this study we will examine how these iron-binding drugs work to inhibit the growth of cancer cells compared to their normal counterparts. These studies are important for the rational design of even more effective chelators. Recent studies in my lab have shown that our new chelators have far greater activity than a drug currently used to treat leukemia, known as hydroxyurea (HU). Our studies also show that the chelators act by a variety of mechanisms, explaining their greater activity than HU. Furthermore, we have shown that these chelators show significant anti-tumour activity in mice. The potential of this form of therapy has been confirmed by the entrance of the chelator, Triapine, into clinical trials (Vion Pharmaceuticals, USA). Our chelators are more effective than Triapine, thus, the present project is crucial for developing novel anti-tumour therapies.Read moreRead less
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
Role Of Transformation And IAPs In Sensitivity Of Cells To TNFalpha
Funder
National Health and Medical Research Council
Funding Amount
$505,786.00
Summary
Current cancer treatments are ineffective and unpleasant for patients. This is because existing cancer treatments target normal as well as cancer cells. New anti-cancer drugs have been designed to encourage cancer cells to kill themselves, by a process called apoptosis, but may still target normal cells. This project aims to discover why cancer cells are susceptible to a novel anti-cancer drug and a natural ligand called TNF but normal cells are not. This will lead to better treatments.