Involvement of the mitochondrial death pathway in chemopreventive benzyl isothiocyanate-induced apoptosis

Yoshimasa Nakamura, Makiko Kawakami, Akira Yoshihiro, Noriyuki Miyoshi, Hajime Ohigashi, Kiyoshi Kawai, Toshihiko Osawa, Koji Uchida

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Abstract

In the present study, we studied the molecular mechanism underlying cell death induced by a cancer chemoprotective compound benzyl isothiocyanate (BITC). The cytotoxic effect of BITC was examined in rat liver epithelial RL34 cells. Apoptosis was induced when the cells were treated with 20 μM BITC, characterized by the appearance of phosphatidylserine on the outer surface of the plasma membrane and caspase-3 activation, whereas no caspase activation and propidium iodide incorporation into cell were detected with 50 μM BITC that induced necrosis. The mitochondrial death pathway was suggested to be involved in BITC-induced apoptosis because the treatment of cells with BITC-induced caspase-9-dependent apoptosis and mitochondrial transmembrane potential (Δψm) alteration. We demonstrated here for the first time that BITC directly modifies mitochondrial functions, including inhibition of respiration, mitochondrial swelling, and release of cytochrome c. Moreover, glutathione depletion by diethyl maleate significantly accelerated BITC-triggered apoptosis, suggesting the involvement of a redox-dependent mechanism. This was also implicated by the observations that intracellular accumulation of reactive oxygen species, including superoxide (O2.-) and hydroperoxides (HPOs), was indeed detected in the cells treated with BITC and that the intracellular HPO level was significantly attenuated by pretreatment with N-acetylcysteine. The treatment with a pharmacological scavenger of O2.-, Tiron, also diminished the HPO formation by ∼80%, suggesting that most of the HPOs were H2O2 derived from the dismutation of O2.-. These results suggest that BITC induces apoptosis through a mitochondial redox-sensitive mechanism.

Original languageEnglish
Pages (from-to)8492-8499
Number of pages8
JournalJournal of Biological Chemistry
Volume277
Issue number10
DOIs
Publication statusPublished - Mar 8 2002
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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    Nakamura, Y., Kawakami, M., Yoshihiro, A., Miyoshi, N., Ohigashi, H., Kawai, K., Osawa, T., & Uchida, K. (2002). Involvement of the mitochondrial death pathway in chemopreventive benzyl isothiocyanate-induced apoptosis. Journal of Biological Chemistry, 277(10), 8492-8499. https://doi.org/10.1074/jbc.M109760200