Enhanced cellular respiration in cells exposed to doxorubicin

Abdul Kader Souid, Harvey S. Penefsky, Peter D. Sadowitz, Bonnie Toms

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


Doxorubicin executes topoisomerase II mediated apoptosis, a process known to result in mitochondrial dysfunction, such as the leakage of cytochrome c and the opening of mitochondrial permeability transition pores (PTP). To further define the effects of doxorubicin on cell metabolism, we measured cellular respiration, cellular ATP, DNA fragmentation, and cytochrome c leakage in Jurkat (supersensitive), human leukemia-60 (HL-60, sensitive), and HL-60/MX2 (resistant) cells following exposure to 1.0 μM doxorubicin for 30 min. The measurements were made after 24 h of exposure to the drug. In Jurkat and HL-60 cells, doxorubicin treatment increased cellular mitochondrial oxygen consumption and ATP content by 2-3-fold. The increment in oxygen consumption was blocked by the pan-caspase inhibitor benzyloxycarbonyl-Val-Ala-DL-Asp-fluoromethylketone (zVAD-fmk) and by the PTP inhibitor cyclosporin A. In HL-60/MX2 cells, which are resistant because of a reduced topoisomerase II activity, doxorubicin treatment was without effect on either respiration or ATP content, suggesting that topoisomerase II was essential for induction of apoptosis and stimulation of respiration and ATP content. The conclusion that both of the latter processes were products of oxidations in the mitochondrial respiratory chain was supported by the further observation that rotenone and sodium cyanide inhibited oxygen consumption and substantially lowered ATP content in the treated and untreated cells. Thus, oxidative phosphorylation is enhanced in cells briefly incubated with doxorubicin for as long as 24 h post drug exposure despite apoptosis-associated mitochondrial insults caused by the drug.

Original languageEnglish
Pages (from-to)307-321
Number of pages15
JournalMolecular Pharmaceutics
Issue number3
Publication statusPublished - May 2006
Externally publishedYes


  • Apoptosis
  • Caspases
  • Cell death
  • Doxorubicin
  • Mitochondria

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmaceutical Science
  • Drug Discovery


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