Molecular mechanism of diclofenac-induced apoptosis of promyelocytic leukemia: Dependency on reactive oxygen species, Akt, Bid, cytochrome c, and caspase pathway

Akiko Inoue, Shikibu Muranaka, Hirofumi Fujita, Tomoko Kanno, Hiroshi Tamai, Kozo Utsumi

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72 Citations (Scopus)


Nonsteroidal anti-inflammatory drugs (NSAIDs) induce apoptosis in a variety of cells, but the mechanism of this effect has not been fully elucidated. We report that diclofenac, a NSAID, induces growth inhibition and apoptosis of HL-60 cells through modulation of mitochondrial functions regulated by reactive oxygen species (ROS), Akt, caspase-8, and Bid. ROS generation occurs in an early stage of diclofenac-induced apoptosis preceding cytochrome c release, caspase activation, and DNA fragmentation. N-Acetyl-l-cysteine, an antioxidant, suppresses ROS generation, Akt inactivation, caspase-8 activation, and DNA fragmentation. Cyclic AMP, an inducer of Akt phosphorylation, suppresses Akt inactivation, Bid cleavage, and DNA fragmentation. LY294002, a PI3 kinase inhibitor, enhances Akt inactivation and DNA fragmentation. Ac-IETD-CHO, a caspase-8 inhibitor, suppresses Bid cleavage and DNA fragmentation. z-VAD-fmk, a universal caspase inhibitor, but not cyclosporin A (CsA), an inhibitor of mitochondrial membrane permeability transition, suppresses DNA fragmentation. These results suggest the sequential mechanism of diclofenac-induced apoptosis of HL-60 cells: ROS generation suppresses Akt activity, thereby activating caspase-8, which stimulates Bid cleavage and induces cytochrome c release and the activation of caspase-9 and-3 in a CsA-insensitive mechanism. Furthermore, we found that 2-methoxyestradiol (2-ME), a superoxide dismutase inhibitor, significantly enhances diclofenac-induced apoptosis; that is, diclofenac combined with 2-ME may have therapeutic potential in the treatment of human leukemia.

Original languageEnglish
Pages (from-to)1290-1299
Number of pages10
JournalFree Radical Biology and Medicine
Issue number8
Publication statusPublished - Oct 15 2004
Externally publishedYes



  • 2-Methoxyestradiol
  • Apoptosis
  • Diclofenac
  • Free radicals
  • HL-60 cells
  • Mitochondria
  • Reactive oxygen species

ASJC Scopus subject areas

  • Medicine(all)
  • Toxicology
  • Clinical Biochemistry

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