Nitric-oxide-induced apoptosis in human leukemic lines requires mitochondrial lipid degradation and cytochrome C release.
We have previously shown that nitric oxide (NO) stimulates apoptosis in different human neoplastic lymphoid cell lines through activation of caspases not only via CD95/CD95L interaction, but also independently of such death receptors. Here we investigated mitochondria-dependent mechanisms of NO-induced apoptosis in Jurkat leukemic cells. NO donor glycerol trinitrate (at the concentration, which induces apoptotic cell death) caused (1) a significant decrease in the concentration of cardiolipin, a major mitochondrial lipid; (2) a downregulation in respiratory chain complex activities; (3) a release of the mitochondrial protein cytochrome c into the cytosol; and (4) an activation of caspase-9 and caspase-3. These changes were accompanied by an increase in the number of cells with low mitochondrial transmembrane potential and with a high level of reactive oxygen species production. Higher resistance of the CD95-resistant Jurkat subclone (APO-R) cells to NO-mediated apoptosis correlated with the absence of cytochrome c release and with less alterations in other mitochondrial parameters. An inhibitor of lipid peroxidation, trolox, significantly suppressed NO-mediated apoptosis in APO-S Jurkat cells, whereas bongkrekic acid (BA), which blocks mitochondrial permeability transition, provided only a moderate antiapoptotic effect. Transfection of Jurkat cells with bcl-2 led to a complete block of apoptosis due to the prevention of changes in mitochondrial functions. We suggest that the mitochondrial damage (in particular, cardiolipin degradation and cytochrome c release) induced by NO in human leukemia cells plays a crucial role in the subsequent activation of caspase and apoptosis.
Ushmorov
A
A
Division of Immunochemistry, Tumor Immunology Program, German Cancer Research Center, Heidelberg, Germany.
Ratter
F
F
Lehmann
V
V
Dröge
W
W
Schirrmacher
V
V
Umansky
V
V
D017209:Apoptosis / Q000187:drug effects*; D002308:Cardiolipins / Q000378:metabolism; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002839:Chromans / Q000494:pharmacology; D003574:Cytochrome c Group / Q000378:metabolism*; D004351:Drug Resistance; D004789:Enzyme Activation / Q000187:drug effects; D019254:Genes, bcl-2; D006801:Humans; D019169:Jurkat Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008066:Lipolysis; D008563:Membrane Lipids / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism*; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D005996:Nitroglycerin / Q000494:pharmacology; D010085:Oxidative Phosphorylation / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000502:physiology; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins / Q000502:physiology; D013268:Stimulation, Chemical; D014162:Transfection; D014407:Tumor Cells, Cultured / Q000187:drug effects
D002308:Cardiolipins; D002839:Chromans; D003574:Cytochrome c Group; D008563:Membrane Lipids; D020030:Nitric Oxide Donors; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D011993:Recombinant Fusion Proteins; D009569:Nitric Oxide; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D020169:Caspases; D005996:Nitroglycerin; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid