Elsevier

Biochemical Pharmacology

Volume 57, Issue 5, 1 March 1999, Pages 481-489
Biochemical Pharmacology

Molecular and Cellular Pharmacology
Structural and functional impairment of mitochondria in adriamycin-induced cardiomyopathy in mice: suppression of cytochrome c oxidase II gene expression

https://doi.org/10.1016/S0006-2952(98)00305-0Get rights and content

Abstract

The use of adriamycin (ADR) in cancer chemotherapy has been limited due to its cumulative cardiovascular toxicity. Earlier observations that ADR interacts with mitochondrial cytochrome c oxidase (COX) and suppresses its enzyme activity led us to investigate ADR’s action on the cardiovascular functions and heart mitochondrial morphology in Balb-c mice i.p. treated with ADR for several weeks. At various times during treatment, the animals were assessed for cardiovascular functions by electrocardiography and for heart tissue damage by electron microscopy. In parallel, total RNA was extracted from samples of dissected heart and analyzed by Northern blot hybridization to determine the steady-state level of three RNA transcripts encoded by the COXII, COXIII, and COXIV genes. Similarly, samples obtained from the liver of the same animals were analyzed for comparative studies. Our results indicated that 1) treatment of mice with ADR caused cardiovascular arrhythmias characterized by bradycardia, extension of ventricular depolarization time (tQRS), and failure of QRS at high concentrations (10–14 mg/kg body weight cumulative dose); 2) the heart mitochondria underwent swelling, fusion, dissolution, and/or disruption of mitochondrial cristae after several weeks of treatment. Such abnormalities were not observed in the mitochondria of liver tissue; and 3) among the three genes of COX enzyme examined, only COXII gene expression was suppressed by ADR treatment, mainly after 8 weeks in both heart and liver. Knowing that heart mitochondria represent almost 40% of heart muscle by weight, we conclude that the deteriorating effects of ADR on cardiovascular function involve mitochondrial structural and functional impairment.

Section snippets

Chemicals and biologicals

Adriblastina (ADR.HCl) purchased in the form of lyophilized powder (containing 10 mg of ADR.HCl, 50 mg of lactose, and 1 mg of methylparaben) from Farmitalia Carlo Erba was reconstituted prior to injection. DEPC (diethyl pyrocarbonate), guanidine, thiocyanate salt and sarcosyl (N-lauroyl-sarcosine) were purchased from SIGMA, sodium citrate from Mallinckrodt, and 2-mercaptoethanol from BDH Chemicals Ltd. SDS was purchased from SERVA. Ultra pure agarose was purchased from BRL, Life Technologies

Changes in R-R interval and QRS failure

Analysis of the ECG during the 300 sec recording period showed a progressive increase in the R-R interval, indicating development of bradycardia (Fig. 1A). By the end of the recording period (t = 300 sec), the R-R interval reached values which varied from 10% (Fig. 1Ab) to 40% (Fig. 1Aa), as compared to values seen at the start of the recording period (t = 1 sec). In animals treated with ADR, this increase in the R-R interval was much higher compared to that of controls. An increase in the R-R

Discussion

ADR-induced cardiomyopathy has long been a serious drawback in treating human cancers effectively. Despite the plethora of information accumulated thus far, the precise mechanism(s) underlying the cardiovascular effects of ADR are not known. Although the theory of free radical formation has been considered as a major mechanism for the destructive process initiated by ADR on the heart, there are still contradictory results concerning the ability of free radical scavengers to prevent ADR-induced

Acknowledgements

We would like to thank Drs. E. A. Schon of Columbia University and P. Dannies of Yale University School of Medicine for kindly providing the DNA probes and primers used in this study. We would also like to thank Dr. E. Nikolakaki, Dept. of Chemistry, Aristotle University of Thessaloniki, for her contribution to RNA extraction as well as E. Neofytou and K. Dimopoulou for technical help in the electron microscopy study. This study was supported in part by a grant from the National Drug

References (41)

  • A.R Spurr

    A low viscosity epoxy resin embedding medium for electron microscopy

    J Ultrastruct Res

    (1969)
  • P Chomczynski et al.

    Single-step method of RNA isolation by acid guanidinium. Thiocyanate-phenol-chloroform extraction

    Anal Biochem

    (1987)
  • Y.J Kang et al.

    Suppression of doxorubicin cardiotoxicity by overexpression of catalase in the heart of transgenic mice

    J Biol Chem

    (1996)
  • R.Y.J Tamminga et al.

    Ventricular late potentials: Another expression of cardiotoxicity of cytostatic drugs in children?

    Int J Cardiol

    (1992)
  • R.D Olson et al.

    Doxorubicin cardiotoxicity: Analysis of prevailing hypotheses

    FASEB J

    (1990)
  • J.H Doroshow

    Effect of anthracycline antibiotics on oxygen radical formation in rat heart

    Cancer Res

    (1983)
  • E.G Mimnaugh et al.

    Adriamycin-enhanced membrane lipid peroxidation in isolated rat nuclei

    Cancer Res

    (1985)
  • E Bachmann et al.

    Effects of seven anthracycline antibiotics on electrocardiogram and mitochondrial function of rat hearts

    Agents Actions

    (1975)
  • T.J Lambidis et al.

    Structural and functional effects of adriamycin on cardiac cells in vitro

    Cancer Res

    (1980)
  • E.A Griffin-Green et al.

    Anthracycline binding to synthetic and natural membranes. A study using resonance energy transfer

    Biochemistry

    (1986)

    • Cited by (0)

    View full text
    Copyright © 1999 Elsevier Science Inc. All rights reserved.