Examination Of The Molecular Pharmacology Of Anthracyclines Induced Via Their Interaction With Iron
Funder
National Health and Medical Research Council
Funding Amount
$618,401.00
Summary
Anthracyclines are highly effective anti-cancer drugs, but their use is limited by toxic effects on the heart. This is thought to be due to these drugs directly binding iron (Fe). Indeed, we showed that anthracyclines induced marked changes in the way heart cells utilise Fe (DR1-3, 38; Mol. Pharmacol. 2002, 2003, 2004, 2005). We were the first to show that anthracyclines prevent Fe release from the criticial Fe storage protein ferritin. This prevents the use of Fe for vital processes eg. DNA and ....Anthracyclines are highly effective anti-cancer drugs, but their use is limited by toxic effects on the heart. This is thought to be due to these drugs directly binding iron (Fe). Indeed, we showed that anthracyclines induced marked changes in the way heart cells utilise Fe (DR1-3, 38; Mol. Pharmacol. 2002, 2003, 2004, 2005). We were the first to show that anthracyclines prevent Fe release from the criticial Fe storage protein ferritin. This prevents the use of Fe for vital processes eg. DNA and haem synthesis. Hence, this effect probably contributes to the cytotoxic activity of anthracyclines on the heart. We showed that novel drugs developed in my lab that bind Fe called chelators show high activity in animals (DR4) and prevent anthracycline-mediated Fe accumulation in ferritin. Importantly, Fe chelators have been shown to inhibit anthracycline-mediated cardiotoxicity. Indeed, the clinically used cardioprotective agent, ICRF-187, is actually an Fe chelator (5, DR6). However, ICRF-187 is not totally successful in terms of its cardioprotective effects and can cause myelosuppression (5, DR6). While the clinically used chelator, desferrioxamine (DFO), can prevent anthracycline-mediated cardiotoxicity, its poor membrane permeability limits its effectiveness. Our chelators are highly permeable and overcome the disadvantages of DFO (DR4). Thus, they are vital to examine for preventing anthracycline-mediated cardiotoxicity. In this proposal we will examine the changes in Fe metabolism induced by anthracyclines and test the hypothesis that novel Fe chelators may prevent the cardiotoxicity of these agents. We also aim to be the first to assess if preparation of anthracyclines which cannot bind iron prevents their cardiotoxicity. This will be done by preparing metal complexes of these drugs which prevent Fe-binding eg. anthracycline-zinc complexes. These studies are important for the development of less cardiotoxic forms of these very useful anti-tumour agents.Read moreRead less
Pharmacology Of Potential Anti-Tumour Agents: Iron Chelators Of The BpT Class
Funder
National Health and Medical Research Council
Funding Amount
$585,455.00
Summary
Pharmacology of Potential Anti-Tumour Agents: Iron Chelators of the BpT Class Cancer cells have a high iron requirement for DNA synthesis and many clinical trials showed Fe chelators are effective anti-cancer drugs. Their potential to act as anti-tumour agents has been confirmed by the entrance of Triapine into widespread NCI clinical trials. In this NHMRC Renewal, we will perform pharmacological and preclinical studies to promote the development of BpT chelators as novel anti-tumour agents.
Mitochondrial Iron Overload And Friedreich's Ataxia: The Role Of Frataxin In Iron And Haem Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$285,990.00
Summary
Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. Recent studies using Baker's yeast have shown that the deletion of frataxin results in the accumulation of toxic iron in the mitochondrion. More recently, a variety of studies have shown that FA patients have iron loading within their cells. The iron build-up may cause severe damage. At present, the role of frataxin in mammalian mitochondrial iron metabolism is unknown. Our preliminary studies demonstrate that frataxin i ....Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. Recent studies using Baker's yeast have shown that the deletion of frataxin results in the accumulation of toxic iron in the mitochondrion. More recently, a variety of studies have shown that FA patients have iron loading within their cells. The iron build-up may cause severe damage. At present, the role of frataxin in mammalian mitochondrial iron metabolism is unknown. Our preliminary studies demonstrate that frataxin is down-regulated by either erythroid differentiation or the haem precursor protoporphyrin IX (Becker and Richardson, submitted). These data strongly suggest a role for frataxin in iron metabolism. In the present study we will continue to assess if frataxin plays a role in the way cells handle iron. Using a unique model of mitochondrial iron overload developed in my lab (Richardson et al. (1996) BLOOD 87:3477), we will extensively investigate the iron metabolism of the mitochondrion in order to determine the function of frataxin and its role in Friedreich's ataxia. In addition, we have developed a series of new drugs known as iron chelators that can enter the mitochondrion due to their high lipid solubility (Becker and Richardson 1999 J. Lab. Clin. Med. 134:510). These latter drugs are far more effective than the chelator currently used to treat iron overload, desferrioxamine (DFO). Indeed, our chelators have been designed to result in high iron chelation efficacy but low toxicity (see Becker and Richardson, 1999). This exciting research may be crucial in understanding the development of FA and in creating new therapies such as the use of iron chelators.Read moreRead less
Mitochondrial Iron Overload And Friedreich's Ataxia: The Role Of Frataxin In Iron And Haem Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$606,000.00
Summary
Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. A variety of studies using Baker's yeast and conditional frataxin knockout (KO) mice have shown that deletion of frataxin leads to the accumulation of toxic iron in their mitochondrion. More recently, a variety of studies have shown that FA patients have iron-loading within their mitochondrion. Iron in the highly redox active environment of the mitochondrion could contribute to the generation of cytotoxic radicals that c ....Friedreich's ataxia (FA) is due to the lack of a protein known as frataxin. A variety of studies using Baker's yeast and conditional frataxin knockout (KO) mice have shown that deletion of frataxin leads to the accumulation of toxic iron in their mitochondrion. More recently, a variety of studies have shown that FA patients have iron-loading within their mitochondrion. Iron in the highly redox active environment of the mitochondrion could contribute to the generation of cytotoxic radicals that cause severe damage. Further, cells deficient in frataxin are sensitive to oxidant stress and Fe chelators rescue oxidant-mediated death of cells from FA patients. Indeed, free radical scavengers have shown to be of use in the treatment of this disease. Studies in DR's lab during this NHMRC grant have shown that frataxin is down-regulated by erythroid differentiation or the haem precursor, protoporphyrin IX (BLOOD 2002;99:3813-22). These data indicate a role for frataxin in Fe metabolism and the pathogenesis of FA. In this study we will continue to examine the role of frataxin in the way cells handle Fe using experimental models developed under the current NHMRC grant. These include transfected cell lines with low frataxin expression generated using an expression vector containing anti-sense frataxin cDNA. Further we obtained the frataxin conditional KO mouse and generated a breeding colony. These animals display many of the pathological features of FA and are the best current model of the disease. Indeed, they will be critical for assessing the role of frataxin in Fe metabolism and as a model to test the ability of Fe-binding drugs to prevent the pathology observed. We designed lipid-soluble chelators that can enter the mitochondrion to bind Fe (Biochim Biophys Acta 2001;1536:133-140) and these ligands will be tested to prevent disease progression in the KO mice. This exciting research is crucial for understanding the pathogenesis of FA and in creating new therapies.Read moreRead less
Platelet Glycoprotein Proteolysis: Novel Mechanisms And Risk Factors
Funder
National Health and Medical Research Council
Funding Amount
$441,473.00
Summary
Platelets are the richest source of amyloid precursor protein (APP) in the body. Platelet ADAM10 regulates both the expression and function of the major platelet collagen receptor GPVI, and protective APP processing. Coagulation protein Factor X has a role in activation of ADAM10. This activation is disrupted in blood that has been treated with direct oral anticoagulant (DOAC) rivaroxaban. This grant will investigate the implications for people taking rivaroxaban on regulation of APP and GPVI.
Linkage Infrastructure, Equipment And Facilities - Grant ID: LE180100157
Funder
Australian Research Council
Funding Amount
$600,000.00
Summary
Confocal and single molecule microscopes for systems microscopy. This project aims to establish Australia’s first system microscopy facility with dedicated live-cell confocal and single-molecule fluorescence microscopes. In systems microscopy, the imaging workflow is automated so that large and unbiased data sets of the spatiotemporal organisation of molecules and cells can be generated. Combined with statistical and bioinformatics analyses, image-derived data provides system-wide information th ....Confocal and single molecule microscopes for systems microscopy. This project aims to establish Australia’s first system microscopy facility with dedicated live-cell confocal and single-molecule fluorescence microscopes. In systems microscopy, the imaging workflow is automated so that large and unbiased data sets of the spatiotemporal organisation of molecules and cells can be generated. Combined with statistical and bioinformatics analyses, image-derived data provides system-wide information that is not easily obtainable with other approaches. The project will enable Australian researchers to image and analyse the full complexity of biological systems, potentially transforming cell biology, drug development and understanding the molecular basis of disease. It will also demonstrate how the capacity of microscopy facilities can be enhanced and bias in imaging data reduced by automating data acquisition and mining of image-based data.Read moreRead less
A hierarchical quantum mechanical and classical simulation of biological ion channels. I aim to develop a methodology incorporating molecular quantum
mechanics and classical Brownian mechanics in a way that can be
applied practically to large macromolecular systems, thus relating
fine structural details to experimentally measurable
properties. Specifically, I will apply this methodology to study ion
channels in which the challenge is to relate electronic and atomic
structure to the conduct ....A hierarchical quantum mechanical and classical simulation of biological ion channels. I aim to develop a methodology incorporating molecular quantum
mechanics and classical Brownian mechanics in a way that can be
applied practically to large macromolecular systems, thus relating
fine structural details to experimentally measurable
properties. Specifically, I will apply this methodology to study ion
channels in which the challenge is to relate electronic and atomic
structure to the conductance properties of the channel. Accurately
determining these relationships provides a pathway to developing cures
for many neurological, cardiac, and muscular diseases.
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