ATP depletion alters the mode of cell death induced by benzyl isothiocyanate.
Pro-inflammatory death is presumably an undesirable event in cancer prevention process, thus biochemical comprehension and molecular definition of this process could have important clinical implications. In the present study, we examined the cytophysiological conversion of cell death mode by benzyl isothiocyanate (BITC) in human cervical cancer HeLa cells. The detailed studies using flow cytometric and morphological analyses demonstrated that the cells treated with appropriate concentration (25 microM) of BITC showed apoptotic feature, such as chromatin condensation, DNA fragmentation, and preserved plasma membrane integrity, whereas these features were disappeared by treatment with higher concentration (100 microM). The treatment with 2-deoxyglucose, an inhibitor of ATP synthesis, drastically increased in the ratio of necrotic dead cells, while it influences little that of apoptotic cells. Moreover, an analysis using the mitochondrial DNA-deficient HeLa cells demonstrated that the rho degrees cells were more susceptible to the BITC-induced necrosis-like cell death compared to the wild-type (rho(+)) cells, whereas the ROS production was significantly inhibited in the rho degrees cells. It is likely that the BITC-induced ROS is derived from mitochondrial respiratory chain and ruled out the contribution to the mechanism of cell death mode switching. In addition, the BITC treatment resulted in a more rapid depletion of ATP in the rho degrees cells than in the rho(+) cells. Furthermore, a caspase inhibitor, Z-VAD-fmk counteracted not only apoptosis, but also necrosis-like cell death induced by BITC, suggesting that increment in this cell death pattern might be due to the interruption of events downstream of a caspase-dependent pathway. The obtained data suggested that the decline in the intracellular ATP level plays an important role in tuning the mode of cell death by BITC.
Miyoshi
Noriyuki
N
Laboratory of Biochemistry, Graduate School of Nutritional and Environmental Sciences, and Global COE Program, University of Shizuoka, Shizuoka 422-8526, Japan.
Watanabe
Etsuko
E
Osawa
Toshihiko
T
Okuhira
Masashi
M
Murata
Yoshiyuki
Y
Ohshima
Hiroshi
H
Nakamura
Yoshimasa
Y
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D053938:DNA Fragmentation / Q000187:drug effects; D004272:DNA, Mitochondrial / Q000378:metabolism; D003847:Deoxyglucose / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004996:Ethidium / Q000494:pharmacology; D006367:HeLa Cells; D006801:Humans; D017879:Isothiocyanates / Q000494:pharmacology*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D010718:Phosphatidylserines / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism
D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D004272:DNA, Mitochondrial; D004791:Enzyme Inhibitors; D017879:Isothiocyanates; D010718:Phosphatidylserines; D017382:Reactive Oxygen Species; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; C031403:benzyl isothiocyanate; D000255:Adenosine Triphosphate; D003513:Cycloheximide; D003847:Deoxyglucose; D020169:Caspases; D004996:Ethidium