The secondary alcohol metabolite of doxorubicin irreversibly inactivates aconitase/iron regulatory protein-1 in cytosolic fractions from human myocardium

^a Department of Pharmacology, Catholic University School of Medicine, Rome, Italy
^b Department of Biochemistry, Catholic University School of Medicine, Rome, Italy
^c Department of Gastroenterology, University of Milan School of Medicine-IRCCS Ospedale Maggiore, Italy
^d CNR Center for Cell Pathology, Milan, Italy
^e Department of Cardiac Surgery, G. D'Annunzio University School of Medicine, Chieti, Italy

Anticancer therapy with doxorubicin (DOX) is limited by severe cardiotoxicity, presumably reflecting the intramyocardial formation of drug metabolites that alter cell constituents and functions. In a previous study, we showed that NADPH-supplemented cytosolic fractions from human myocardial samples can enzymatically reduce a carbonyl group in the side chain of DOX, yielding a secondary alcohol metabolite called doxorubicinol (DOXol). Here we demonstrate that DOXol delocalizes low molecular weight Fe(II) from the [4Fe-4S] cluster of cytoplasmic aconitase. Iron delocalization proceeds through the reoxidation of DOXol to DOX and liberates DOX-Fe(II) complexes as ultimate by-products. Under physiologic conditions, cluster disassembly abolishes aconitase activity and forms an apoprotein that binds to mRNAs, coordinately increasing the synthesis of transferrin receptor but decreasing that of ferritin. Aconitase is thus converted into an iron regulatory protein-1 (IRP-1) that causes iron uptake to prevail over sequestration, forming a pool of free iron that is used for metabolic functions. Conversely, cluster reassembly converts IRP-1 back to aconitase, providing a regulatory mechanism to decrease free iron when it exceeds metabolic requirements. In contrast to these physiologic mechanisms, DOXol-dependent iron release and cluster disassembly not only abolish aconitase activity, but also affect irreversibly the ability of the apoprotein to function as IRP-1 or to reincorporate iron within new Fe-S motifs. This damage is mediated by DOX-Fe(II) complexes and reflects oxidative modifications of SH residues having the dual role to coordinate cluster assembly and facilitate interactions of IRP-1 with mRNAs. Collectively, these findings describe a novel mechanism of cardiotoxicity, suggesting that intramyocardial formation of DOXol may perturb the homeostatic processes associated with cluster assembly or disassembly and the reversible switch between aconitase and IRP-1. These results may also provide a guideline to design new drugs that mitigate the cardiotoxicity of DOX.—Minotti, G., Recalcati, S., Mordente, A., Liberi, G., Calafiore, A. M., Mancuso, C., Preziosi, P., Cairo, G. The secondary alcohol metabolite of doxorubicin irreversibly inactivates aconitase/iron regulatory protein-1 in cytosolic fractions from human myocardium. FASEB J. 12, 541–552 (1998)

Key Words: IRP-1 • cardiotoxicity • doxorubicin • alcohol metabolite • DOXol cluster disassembly • iron-responsive elements

This article has been cited by other articles:

				Y. Chen, P. Jungsuwadee, M. Vore, D. A. Butterfield, and D. K. St. Clair Collateral Damage in Cancer Chemotherapy: Oxidative Stress in Nontargeted Tissues Mol. Interv., June 1, 2007; 7(3): 147 - 156. [Abstract] [Full Text] [PDF]

				E. Salvatorelli, S. Guarnieri, P. Menna, G. Liberi, A. M. Calafiore, M. A. Mariggio, A. Mordente, L. Gianni, and G. Minotti Defective One- or Two-electron Reduction of the Anticancer Anthracycline Epirubicin in Human Heart: RELATIVE IMPORTANCE OF VESICULAR SEQUESTRATION AND IMPAIRED EFFICIENCY OF ELECTRON ADDITION J. Biol. Chem., April 21, 2006; 281(16): 10990 - 11001. [Abstract] [Full Text] [PDF]

				X. Xu, H. L. Persson, and D. R. Richardson Molecular Pharmacology of the Interaction of Anthracyclines with Iron Mol. Pharmacol., August 1, 2005; 68(2): 261 - 271. [Abstract] [Full Text] [PDF]

				G. Minotti, P. Menna, E. Salvatorelli, G. Cairo, and L. Gianni Anthracyclines: Molecular Advances and Pharmacologic Developments in Antitumor Activity and Cardiotoxicity Pharmacol. Rev., June 1, 2004; 56(2): 185 - 229. [Abstract] [Full Text] [PDF]

				G. Corna, P. Santambrogio, G. Minotti, and G. Cairo Doxorubicin Paradoxically Protects Cardiomyocytes against Iron-mediated Toxicity: ROLE OF REACTIVE OXYGEN SPECIES AND FERRITIN J. Biol. Chem., April 2, 2004; 279(14): 13738 - 13745. [Abstract] [Full Text] [PDF]

				S. FOGLI, P. NIERI, and M. C. BRESCHI The role of nitric oxide in anthracycline toxicity and prospects for pharmacologic prevention of cardiac damage FASEB J, April 1, 2004; 18(6): 664 - 675. [Abstract] [Full Text] [PDF]

				J. C. Kwok and D. R. Richardson Examination of the Mechanism(s) Involved in Doxorubicin-Mediated Iron Accumulation in Ferritin: Studies Using Metabolic Inhibitors, Protein Synthesis Inhibitors, and Lysosomotropic Agents Mol. Pharmacol., January 1, 2004; 65(1): 181 - 195. [Abstract] [Full Text] [PDF]

				W. Kang and M. Weiss Modeling the Metabolism of Idarubicin to Idarubicinol in Rat Heart: Effect of Rutin and Phenobarbital Drug Metab. Dispos., April 1, 2003; 31(4): 462 - 468. [Abstract] [Full Text] [PDF]

				J. C. Kwok and D. R. Richardson Anthracyclines Induce Accumulation of Iron in Ferritin in Myocardial and Neoplastic Cells: Inhibition of the Ferritin Iron Mobilization Pathway Mol. Pharmacol., April 1, 2003; 63(4): 849 - 861. [Abstract] [Full Text] [PDF]

				J. C. Kwok and D. R. Richardson Unexpected Anthracycline-Mediated Alterations in Iron-Regulatory Protein-RNA-Binding Activity: The Iron and Copper Complexes of Anthracyclines Decrease RNA-Binding Activity Mol. Pharmacol., October 1, 2002; 62(4): 888 - 900. [Abstract] [Full Text] [PDF]

				F. M. Torti and S. V. Torti Regulation of ferritin genes and protein Blood, May 15, 2002; 99(10): 3505 - 3516. [Full Text] [PDF]

				S. Kotamraju, C. R. Chitambar, S. V. Kalivendi, J. Joseph, and B. Kalyanaraman Transferrin Receptor-dependent Iron Uptake Is Responsible for Doxorubicin-mediated Apoptosis in Endothelial Cells. ROLE OF OXIDANT-INDUCED IRON SIGNALING IN APOPTOSIS J. Biol. Chem., May 3, 2002; 277(19): 17179 - 17187. [Abstract] [Full Text] [PDF]

				G. Minotti, R. Ronchi, E. Salvatorelli, P. Menna, and G. Cairo Doxorubicin Irreversibly Inactivates Iron Regulatory Proteins 1 and 2 in Cardiomyocytes: Evidence for Distinct Metabolic Pathways and Implications for Iron-mediated Cardiotoxicity of Antitumor Therapy Cancer Res., December 1, 2001; 61(23): 8422 - 8428. [Abstract] [Full Text] [PDF]

				G. Minotti, A. Saponiero, S. Licata, P. Menna, A. M. Calafiore, G. Teodori, and L. Gianni Paclitaxel and Docetaxel Enhance the Metabolism of Doxorubicin to Toxic Species in Human Myocardium Clin. Cancer Res., June 1, 2001; 7(6): 1511 - 1515. [Abstract] [Full Text] [PDF]

				G. L. Forrest, B. Gonzalez, W. Tseng, X. Li, and J. Mann Human Carbonyl Reductase Overexpression in the Heart Advances the Development of Doxorubicin-induced Cardiotoxicity in Transgenic Mice Cancer Res., September 1, 2000; 60(18): 5158 - 5164. [Abstract] [Full Text]

				G. MINOTTI, G. CAIRO, and E. MONTI Role of iron in anthracycline cardiotoxicity: new tunes for an old song? FASEB J, February 1, 1999; 13(2): 199 - 212. [Abstract] [Full Text]