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
Erythroid Molecular Cascades Involving The Tyrosine Kinase Lyn
Funder
National Health and Medical Research Council
Funding Amount
$496,500.00
Summary
Mature red and white cells develope from hemopoietic stem cells in the adult bone marrow. The production of red blood cells is primarily controlled by the hormone erythropoietin (Epo). The availability of this hormone in a recombinant form has aided in the treatment of numerous forms of anaemia resulting from kidney failure, malignancies, and AIDS. Previously we had identified that the protein Lyn must be present inside primitive red blood cells for Epo to stimulate them to become mature functio ....Mature red and white cells develope from hemopoietic stem cells in the adult bone marrow. The production of red blood cells is primarily controlled by the hormone erythropoietin (Epo). The availability of this hormone in a recombinant form has aided in the treatment of numerous forms of anaemia resulting from kidney failure, malignancies, and AIDS. Previously we had identified that the protein Lyn must be present inside primitive red blood cells for Epo to stimulate them to become mature functional cells. Recently, we have demonstrated that mice lacking the Lyn gene develope major problems with their red blood cells. We have identified several molecules which interact with Lyn in red blood cells. We have shown that a molecule called Cbp is important for Epo function in individual red blood cells and now we plan to investigate its function in whole animals. We have shown that a new molecule called Arp is important for red blood cell development. This protein moves in and out of the nucleus (where DNA is stored) and may be important in the regulation of genes needed for red blood cells. The third gene (AFAPbeta) is also novel and is closely related to another called AFAP-110, which can exert effects on the structure of a cell. Since red blood cells have to shrink considerably during their development, the role of AFAPbeta on red blood cell structure will also be investigated. From these experiments we should develop a much better understanding of how the production of red blood cells is controlled and how diseases of red blood cells (such as anaemia) occur.Read moreRead less