Peroxynitrite-induced apoptosis involves activation of multiple caspases in HL-60 cells.
In this study, we show that caspases 2, 3, 6, and 7 were activated during peroxynitrite-induced apoptosis in human leukemia HL-60 cells and that processing of these caspases was accompanied by cleavage of poly(ADP-ribose) polymerase and lamin B. Treatment of cells with DEVD-fluoromethyl ketone (FMK), a selective inhibitor for caspase 3-like proteases, resulted in a marked diminution of apoptotic cells. VAVAD-FMK, an inhibitor of caspase 2, partially inhibited the apoptotic response to peroxynitrite. However, selective inactivation of caspase 6 by VEID-FMK did not affect apoptosis rates. These data suggest that caspase 3-like proteases and caspase 2, but not caspase 6, are required for peroxynitrite-induced apoptosis in this cell type. Moreover, we demonstrate that peroxynitrite treatment stimulated activation of caspases 8 and 9, two initial caspases in the apoptotic signaling pathway, and preincubation of cells with their inhibitor, IETD-FMK, inhibited activation of caspase 3-like proteases and caspase 2 at the concentration that prevents the apoptosis. These observations, together, suggest that caspase 8 and/or caspase 9 mediates activation of caspase 3-like proteases and caspase 2 during the apoptosis induced by peroxynitrite in HL-60 cells.
Zhuang
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S
Wellman Laboratories of Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA.
Simon
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G
D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D020169:Caspases / Q000187:drug effects* / Q000378:metabolism; D018922:HL-60 Cells / Q000187:drug effects; D006801:Humans; D034921:Lamin Type B; D034882:Lamins; D009566:Nitrates / Q000494:pharmacology*; D009687:Nuclear Proteins / Q000187:drug effects / Q000378:metabolism; D016877:Oxidants / Q000494:pharmacology*; D011065:Poly(ADP-ribose) Polymerases / Q000187:drug effects / Q000378:metabolism
D034921:Lamin Type B; D034882:Lamins; D009566:Nitrates; D009687:Nuclear Proteins; D016877:Oxidants; C039642:peroxynitric acid; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases