Original ContributionAnalyses of the Molecular Mechanism of Adriamycin-Induced Cardiotoxicity
Introduction
Anthraquinones are increasingly used in the treatment of various forms of cancer. However, the therapeutic use is limited by the development of a dose-dependent cardiomyopathy.[1]Although a great deal of alterations on the molecular, functional, and clinical levels were reported,1, 2, 3the basic mechanism that explains the selective susceptibility of the myocardial tissues to adriamycin (AQ) is still far from being clear. Morphological changes of heart mitochondria established during AQ treatment indicate that these organelles are affected. Many research groups have, therefore, focused their scientific interest on the role of heart mitochondria in the development of AQ-related cardiomyopathy.2, 3, 4, 5, 6, 7Most effects that were reported to result from interactions with AQ, such as inhibition of adenine nucleotide translocase[8]or AQ binding to cardiolipin, which inhibits cytochrome oxidase,[9]may occur in mitochondria from other tissues as well.
In contrast toxicological activation of AQ was found to require the addition of NADH in the case of heart mitochondria,[10]while NADH and any other respiratory substrate were ineffective when liver mitochondria were exposed to AQ. The latter observations made by Davies[7]and others2, 11led to the detection of an exogenous mitochondrial NADH dehydrogenase.12, 13This enzyme was earlier shown to be associated with the cytosolic face of the inner membrane of heart mitochondria, while liver mitochondria do not have this type of enzyme.12, 14As demonstrated in previous papers,12, 14this enzyme is able to oxidize cytosolic NADH and donates electrons to the ubiquinone pool of the respiratory chain. The strong negative redox potential of this mitochondrial redox carrier, together with its accessibility to hydrophilic compounds in the cytosol, strongly suggest a reduction of the water-soluble native form of AQ catalyzed by this enzyme in the presence of cytosolic NADH.
In line with this consideration was the finding of different research groups that mitochondria catalyze a single electron reduction of AQ at the expense of extramitochondrial NADH.10, 15Furthermore, it was universally reported that AQ̇ semiquinones (AQ̇) formed in this reaction readily autoxidize and generate radicals.6, 16, 17
While searching for an explanation of the heart-selective toxicogenesis of AQ treatment we became interested in the sequence of toxicological events after NADH-dependent AQ activation in heart mitochondria and the role of the exogenous NADH dehydrogenase therein.
Section snippets
Materials and Methods
Glutamate, succinate, KH2PO4, K2HPO4, triethanolamine, EDTA, DETAPAC, sucrose, KCN, and acetonitrile were obtained from Merck (Darmstadt, Germany); NADH and ADP were from Boehringer (Mannheim, Germany); BSA (fraction V), L-malic acid, fumarate, catalase, and superoxide dismutase (SOD) were purchased from Sigma Chemical (Deisenhofen, Germany); and adriamycin (AQ) came from Farmitalia (Bern, Switzerland). Adriamycin aglycone (AglAQ) was prepared by acid hydrolysis according to Gewirtz and
Results
Fig. 1 indirectly elucidates the involvement of the exogenous NADH dehydrogenase of heart mitochondria in the initial activation step of AQ, giving rise to the existence of paramagnetic AQ̇ semiquinone species (AQ̇). In contrast to succinate-respiring mitochondria, the use of external NADH resulted in the generation of the one-electron reduction product of AQ. The respective ESR signal exhibited a g-value of 2.0039, which is in line with the data reported for AQ̇ semiquinones in the literature.6
Discussion
This study presents experimental evidence on a sequence of toxicogenetic events that are likely to be involved in selective cardiotoxicity of AQ. The initial step in the toxicogenetic activation of AQ glycosides, the molecular form commonly used in therapy, is the one-electron reduction to the unstable AQ̇ form. This reaction was shown to require cytosolic NADH, and heart mitochondria strongly suggesting the involvement of the catalytic activity of the exogenous NADH dehydrogenase of this type
Acknowledgements
The skillful technical assistance of W. Stamberg is gratefully acknowledged.
References (27)
Interactions of adriamycin aglycones with mitochondria may mediate adriamycin cardiotoxicity
Int. J. Biochem.
(1994)- et al.
OḢ-generation by adriamycin semiquinone and H2O2; An explanation for the cardiotoxicity of anthracycline antibiotics
Biochem. Biophys. Res. Commun.
(1983) - et al.
Interaction of adriamycin aglycones with isolated mitochondria. Effect of selenium deficiency
Biochem. Pharmacol.
(1993) - et al.
Redox cycling of anthracyclines by cardiac mitochondria. II. Formation of superoxide anion, hydrogen peroxide, and hydroxyl radical
J. Biol. Chem.
(1986) - et al.
Redox cycling of anthracyclines by cardiac mitochondria. I. Anthracycline radical formation by NADH dehydrogenase
J. Biol. Chem.
(1986) - et al.
Age-related acute adriamycin cardiotoxicity in mice
J. Mol. Cell Cardiol.
(1994) Inactivation of cytochrome c oxidase activity in mitochondrial membranes during redox cycling of doxorubicin
Biochem. Pharmacol.
(1991)Identification of the site of adriamycin-activation in the heart cell
Biochem. Pharmacol.
(1988)- et al.
Inhibition of coenzyme Q10-enzymes, succinoxidase and NADH-oxidase by adriamycin and other quinones having antitumor activity
Biochem. Biophys. Res. Commun.
(1974) - et al.
Oxidation of cytosolic NADH via complex I of heart mitochondria
Arch. Biochem. Biophys.
(1996)
Metabolism of the anthracycline antibiotic daunorubicin to daunorubicinol and deoxydaunorubicinol aglycone in hepatocytes isolated from the rat and the rabbit
Biochem. Pharmacol.
Spin trapping: ESR parameters of spin adducts
Free Radic. Biol. Med.
Effect of alpha-lipoic acid and dihydrolipoic acid on ischemia/reperfusion injury of the heart and heart mitochondria
Biochim. Biophys. Acta
Cited by (191)
Effect of ethanolic extract of Rosa centifolia against doxorubicin induced nephrotoxicity in albino rats
2021, Journal of Ayurveda and Integrative MedicineAnti-oxidant impact of Lisinopril and Enalapril against acute kidney injury induced by doxorubicin in male Wistar rats: involvement of kidney injury molecule-1
2021, HeliyonCitation Excerpt :On the other hand, DOX caused a significant decrease in TAC concentration when compared to the control -ve group. Previous studies attributed these findings to the ring structure of anthracycline of DOX that increases the enzymatic and non-enzymatic single-electron redox cycle release of ROS from molecular oxygen [22]. Various researches showed that free radicals induced by DOX treatment cause depletion of the antioxidant defense system and thus increase the oxidation process of both lipids and proteins in tissues of DOX-treated rats [23].
The copper(II) complexes of new anthrahydrazone ligands: In vitro and in vivo antitumor activity and structure-activity relationship
2020, Journal of Inorganic Biochemistry