Induction of apoptosis by vanilloid compounds does not require de novo gene transcription and activator protein 1 activity.
The vanilloid compounds, capsaicin and resiniferatoxin, are quinone analogues that inhibit the NADH-plasma membrane electron transport system and induce apoptosis in transformed cells. Because disruption of the mitochondrial transmembrane potential (deltapsi(m)) is a common metabolic alteration in all apoptotic processes, we have evaluated the role of mitochondrial permeability transition in apoptosis induced by vanilloids in Jurkat cells. Using a cytofluorimetric approach, we have determined that DNA nuclear loss induced by vanilloids is preceded by an increase of the production of reactive oxygen species (ROS) and by a subsequent deltapsi(m) dissipation in T-cell lines. Overexpression of Bcl-2 and pretreatment with either the immunosuppressant cyclosporin A or the glutathione precursor N-acetyl-L-cysteine blocked deltapsi(m) disruption and apoptosis, but not the generation of ROS induced by these compounds. Capsaicin and resiniferatoxin were found to activate both isoforms of c-jun-NH2-kinase (JNK), with a maximal activity after 30 min of treatment. Despite the activation of JNK, there was no induction of activator protein 1 (AP-1) activity as determined by gel shift assay or of induction of an AP-1-responsive reporter. On the other hand, vanilloids did not signal for c-Raf kinase and extracellular signal-regulated kinases 1 and 2. We suggest that ROS generation by inhibition of the NADH-dependent plasma membrane electron transport system resulted in the oxidation of mitochondrial megachannel pores that allows for the disruption of deltapsi(m) and apoptosis, and that AP-1 activation is not required for vanilloid-induced apoptosis.
Macho
A
A
Departamento de Fisiología e Immunología, Facultad de Medicina, Universidad de Córdoba, Spain.
Blázquez
M V
MV
Navas
P
P
Muñoz
E
E
D000111:Acetylcysteine / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D001665:Binding Sites; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002211:Capsaicin / Q000494:pharmacology*; D016572:Cyclosporine / Q000494:pharmacology; D004268:DNA-Binding Proteins / Q000378:metabolism; D004224:Diterpenes / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases; D019169:Jurkat Cells / Q000166:cytology / Q000187:drug effects; D008564:Membrane Potentials; D008928:Mitochondria / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases; D009247:NADH, NADPH Oxidoreductases / Q000037:antagonists & inhibitors; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000502:physiology*; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
D004268:DNA-Binding Proteins; D004224:Diterpenes; D004791:Enzyme Inhibitors; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D016572:Cyclosporine; C024353:resiniferatoxin; D009247:NADH, NADPH Oxidoreductases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D002211:Capsaicin; D000111:Acetylcysteine