Metallothionein inhibits doxorubicin-induced mitochondrial cytochrome c release and caspase-3 activation in cardiomyocytes

Guang Wu Wang, Jon B. Klein, Yujian Kang

Research output: Contribution to journalArticle

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Abstract

Previous studies using transgenic mice in which metallothionein (MT) was overexpressed only in the heart have demonstrated that MT protects from oxidative cardiac injury induced by doxorubicin (DOX), an important anticancer agent. MT cardioprotection is associated with its antiapoptotic effect. The present study was undertaken to test the hypothesis that MT suppresses DOX-induced apoptosis through inhibition of mitochondrial cytochrome c release and caspase-3 activation. Primary cultures of cardiomyocytes isolated from the hearts of transgenic neonatal mice and nontransgenic controls were treated with DOX at a clinically relevant concentration (1.0 μM) for varying time periods. Apoptosis was detected in nontransgenic cardiomyocyte cultures by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling and Annexin V-fluorescein isothiocyanate binding. This apoptotic effect was significantly suppressed in the MT-overexpressing transgenic cardiomyocytes. Western blot analysis revealed that DOX caused mitochondrial cytochrome c release. Furthermore, caspase-3 activation was observed. The activation of this apoptotic pathway by DOX was dramatically inhibited in the MT-overexpressing cardiomyocytes. To elucidate the role of reactive oxygen species (ROS) in the activation of the cytochrome c-mediated caspase-3 activation pathway, the intracellular levels of ROS and their localization were detected by fluorescent confocal microscopy. Mitochondrial ROS concentrations were dramatically elevated by DOX in nontransgenic cardiomyocytes. This elevation was completely inhibited almost in the MT-overexpressing cardiomyocytes. Thus, these results demonstrate that MT suppresses DOX-induced apoptosis in cardiomyocytes through, at least in part, inhibition of the cytochrome c-mediated apoptotic pathway.

Original languageEnglish (US)
Pages (from-to)461-468
Number of pages8
JournalJournal of Pharmacology and Experimental Therapeutics
Volume298
Issue number2
StatePublished - Aug 2 2001
Externally publishedYes

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Metallothionein
Cytochromes c
Cardiac Myocytes
Caspase 3
Doxorubicin
Reactive Oxygen Species
Apoptosis
Transgenic Mice
DNA Nucleotidylexotransferase
Annexin A5
Fluorescein
Confocal Microscopy
Antineoplastic Agents
Western Blotting
Wounds and Injuries

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • Pharmacology

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Metallothionein inhibits doxorubicin-induced mitochondrial cytochrome c release and caspase-3 activation in cardiomyocytes. / Wang, Guang Wu; Klein, Jon B.; Kang, Yujian.

In: Journal of Pharmacology and Experimental Therapeutics, Vol. 298, No. 2, 02.08.2001, p. 461-468.

Research output: Contribution to journalArticle

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