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Generation of hydrogen peroxide precedes loss of mitochondrial membrane potential during DNA alkylation‐induced apoptosis
Author(s) -
Tada-Oikawa Saeko,
Oikawa Shinji,
Kawanishi Michiko,
Yamada Michiyuki,
Kawanishi Shosuke
Publication year - 1999
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(98)01618-4
Subject(s) - hydrogen peroxide , apoptosis , membrane potential , chemistry , mitochondrial dna , alkylation , mitochondrion , membrane , reactive oxygen species , inner mitochondrial membrane , microbiology and biotechnology , dna , biophysics , biochemistry , biology , gene , catalysis
Pulsed field gel electrophoresis showed that the initiation time of DNA breakage induced by the DNA alkylating agent duocarmycin A, which is not a redox‐cycling agent, was almost the same in the human leukemia cell line HL‐60 and its H 2 O 2 ‐resistant clone HP100. Catalase activity of HP100 cells was much higher than that of HL‐60 cells. Duocarmycin A‐mediated DNA ladder formation in HP100 cells was delayed compared with that in HL‐60 cells, suggesting the involvement of H 2 O 2 in duocarmycin A‐induced apoptosis. Flow cytometry demonstrated that peroxide formation preceded loss of mitochondrial membrane potential (ΔΨm) in cells treated with duocarmycin A. Then, caspase‐3 was activated, followed by DNA ladder formation. These findings suggest that DNA damage by duocarmycin A induces H 2 O 2 generation, which causes ΔΨm loss and subsequently caspase‐3 activation, resulting in apoptosis.