H2O2 and antioxidants have opposite effects on activation of NF-kappa B and AP-1 in intact cells: AP-1 as secondary antioxidant-responsive factor.
We show that AP-1 is an antioxidant-responsive transcription factor. DNA binding and transactivation by AP-1 were induced in HeLa cells upon treatment with the antioxidants pyrrolidine dithiocarbamate (PDTC) and N-acetyl-L-cysteine (NAC), and upon transient expression of the antioxidative enzyme thioredoxin. While PDTC and NAC enhanced DNA binding and transactivation of AP-1 in response to phorbol ester, the oxidant H2O2 suppressed phorbol ester activation of the factor. H2O2 on its own was only a weak inducer of AP-1. Activation of AP-1 by PDTC was dependent on protein synthesis and involved transcriptional induction of c-jun and c-fos genes. Transcriptional activation of c-fos by PDTC was conferred by the serum response element, suggesting that serum response factor and associated proteins function as primary antioxidant-responsive transcription factors. In the same cell line, the oxidative stress-responsive transcription factor NF-kappa B behaved in a manner strikingly opposite to AP-1. DNA binding and transactivation by NF-kappa B were strongly activated by H2O2, while the antioxidants alone were ineffective. H2O2 potentiated the activation of NF-kappa B by phorbol ester, while PDTC and NAC suppressed PMA activation of the factor. PDTC did not influence protein kinase C (PKC) activity and PKC activation by PMA, indicating that the antioxidant acted downstream of and independently from PKC.
Meyer
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Laboratory for Molecular Biology of the Ludwig-Maximilians-University, Martinsried, Germany.
Schreck
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Baeuerle
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PA
D000975:Antioxidants / Q000494:pharmacology*; D001483:Base Sequence; D004247:DNA; D016762:Genes, fos; D016758:Genes, jun; D006367:HeLa Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism*; D011759:Pyrrolidines / Q000494:pharmacology; D012045:Regulatory Sequences, Nucleic Acid; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013859:Thiocarbamates / Q000494:pharmacology; D013879:Thioredoxins / Q000096:biosynthesis; D014158:Transcription, Genetic; D015533:Transcriptional Activation
D000975:Antioxidants; D016328:NF-kappa B; D009838:Oligodeoxyribonucleotides; D016755:Proto-Oncogene Proteins c-jun; D011759:Pyrrolidines; D013859:Thiocarbamates; C020972:pyrrolidine dithiocarbamic acid; D013879:Thioredoxins; D004247:DNA; D006861:Hydrogen Peroxide; D013755:Tetradecanoylphorbol Acetate