TY - JOUR
T1 - Involvement of the mitochondrial death pathway in chemopreventive benzyl isothiocyanate-induced apoptosis
AU - Nakamura, Yoshimasa
AU - Kawakami, Makiko
AU - Yoshihiro, Akira
AU - Miyoshi, Noriyuki
AU - Ohigashi, Hajime
AU - Kawai, Kiyoshi
AU - Osawa, Toshihiko
AU - Uchida, Koji
PY - 2002/3/8
Y1 - 2002/3/8
N2 - 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.
AB - 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.
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U2 - 10.1074/jbc.M109760200
DO - 10.1074/jbc.M109760200
M3 - Article
C2 - 11751909
AN - SCOPUS:0037040918
VL - 277
SP - 8492
EP - 8499
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 10
ER -