Mitochondrial apoptosis-inducing factor is involved in doxorubicin-induced toxicity on H9c2 cardiomyoblasts

Ana C. Moreira, Ana F. Branco, Susana F. Sampaio, Teresa Cunha-Oliveira, Tatiana R. Martins, Jon Holy, Paulo J. Oliveira, Vilma A. Sardão

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

The cardiotoxicity induced by the anti-cancer doxorubicin involves increased oxidative stress, disruption of calcium homeostasis and activation of cardiomyocyte death. Nevertheless, antioxidants and caspase inhibitors often show little efficacy in preventing cell death. We hypothesize that a caspase-independent cell death mechanism with the release of the apoptosis-inducing factor from mitochondria is involved in doxorubicin toxicity. To test the hypothesis, H9c2 cardiomyoblasts were used as model for cardiac cells. Our results demonstrate that z-VAD-fmk, a pan-caspase inhibitor, does not prevent doxorubicin toxicity in this cell line. Doxorubicin treatment results in AIF translocation to the nuclei, as confirmed by Western Blotting of cell fractions and confocal microscopy. Also, doxorubicin treatment of H9c2 cardiomyoblasts resulted in the appearance of 50. kbp DNA fragments, a hallmark of apoptosis-inducing factor nuclear effects. Apoptosis-inducing factor knockdown using a small-interfering RNA approach in H9c2 cells resulted in a reduction of doxorubicin toxicity, including decreased p53 activation and poly-ADP-ribose-polymerase cleavage. Among the proteases that could be responsible for apoptosis-inducing factor cleavage, doxorubicin decreased calpain activity but increased cathepsin B activation, with inhibition of the latter partly decreasing doxorubicin toxicity. Altogether, the results support that apoptosis-inducing factor release is involved in doxorubicin-induced H9c2 cell death, which explains the limited ability of caspase inhibitors to prevent toxicity.

Original languageEnglish (US)
Pages (from-to)2468-2478
Number of pages11
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Volume1842
Issue number12
DOIs
StatePublished - Dec 1 2014

Keywords

  • Apoptosis
  • Apoptosis-inducing factor
  • Cardiomyoblast
  • Doxorubicin

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    Moreira, A. C., Branco, A. F., Sampaio, S. F., Cunha-Oliveira, T., Martins, T. R., Holy, J., Oliveira, P. J., & Sardão, V. A. (2014). Mitochondrial apoptosis-inducing factor is involved in doxorubicin-induced toxicity on H9c2 cardiomyoblasts. Biochimica et Biophysica Acta - Molecular Basis of Disease, 1842(12), 2468-2478. https://doi.org/10.1016/j.bbadis.2014.09.015