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Trimidox Induces Apoptosis via Cytochrome c Release in NALM‐6 Human B Cell Leukaemia Cells
Author(s) -
Kanno Syuichi,
Uwai Kohji,
Tomizawa Ayako,
Hiura Takako,
Osanai Yuu,
Ujibe Mayuko,
Takeshita Mitsuhiro,
Ohtake Takaharu,
Kimura Katsuhiko,
Ishikawa Masaaki
Publication year - 2006
Publication title -
basic and clinical pharmacology and toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.805
H-Index - 90
eISSN - 1742-7843
pISSN - 1742-7835
DOI - 10.1111/j.1742-7843.2006.pto_188.x
Subject(s) - apoptosis , microbiology and biotechnology , cytochrome c , jurkat cells , xiap , cell culture , k562 cells , caspase , biology , kinase , protein kinase a , mapk/erk pathway , p38 mitogen activated protein kinases , programmed cell death , biochemistry , immunology , t cell , genetics , immune system
Abstract: Trimidox (3,4,5‐trihydroxybenzamidoxime) has been shown to reduce the activity of ribonucleotide reductase accompanied by growth inhibition and the differentiation of mammalian cells. Here we examine the induction of apoptosis by trimidox in several human leukaemia cell lines, focusing on the release of cytochrome c and the activation of caspase proteases in the human B cell line NALM‐6. Induction of apoptosis by trimidox (300 μM) was detected in NALM‐6, HL‐60 (premyelocytic leukaemia cells), MOLT‐4 (an acute lymphoblastic leukaemia cells), Jurkat (a T‐cell leukaemia cells), U937 (expressing many monocyte‐like characteristics), and K562 (erythroleukaemia). NALM‐6 was most affected by trimidox among leukaemia cells; therefore, we employed NALM‐6 cells in the subsequent experiments. The cells showed a time‐dependent increase in DNA damage after trimidox (250 μM) treatment. A significant increase in the amount of cytochrome c release was detected after treatment with trimidox. Bcl‐2 and Bax protein expressions were not changed by trimidox. Caspase‐3 and ‐9 were activated by incubation with trimidox, whereas caspase‐8 was not. Furthermore, trimidox‐induced apoptosis was prevented by a broad‐spectrum caspase inhibitor, a caspase‐3, and a caspase‐9 inhibitor, but not by a caspase‐8 inhibitor. Inhibition of c‐Jun NH 2 ‐terminal kinase (JNK) by SP600125 appreciably protected cells from trimidox‐induced apoptosis, but no effect inhibition of p38 mitogen‐activated protein kinase (MAPK) by SB203580. In contrast, extracellular signal‐regulated kinase (ERK) inhibitors U0126 and PD98059 strongly potentiated the apoptotic effect of trimidox. This report shows that the induction of apoptosis by trimidox occurs through a cytochrome c‐dependent pathway, which sequentially activates caspase‐3 and caspase‐9.