Dual activity of pyrrolidine dithiocarbamate on kappa B-dependent gene expression in U937 cells: I. Regulation by the phorbol ester TPA.
Pyrrolidine dithiocarbamate (PDTC) has been widely used as an inhibitor of the nuclear factor-kappa B, (NF-kappa B) signalling pathway. Here, we show that kappa B-dependent reporter gene expression induced by low concentrations of 12-O-tetradecanoylphorbol-13-acetate (TPA) is potentiated by PDTC in the human pro-monocytic U937 cell line. The stimulatory effect of PDTC on kappa B-dependent gene expression was shown with a 4 x kappa B chloramphenicol acetyltransferase construct and required an intact kappa B element in the human immunodeficiency virus long terminal repeat (HIV-1 LTR). Unexpectedly, an HIV-1 LTR construct with a mutation of the activator protein 2 (AP-2) binding site located between the two kappa B elements was unresponsive to the stimulatory effect of PDTC with TPA. The stimulation or inhibition of kappa B-dependent gene expression was dependent on PDTC pre-treatment and the concentration of TPA. No stimulatory effect on HIV-1 LTR activity was observed with the metal chelator dipyridyl or the anti-oxidant N-acetyl-L-cysteine. These results are consistent with the hypothesis that PDTC treatment potentiated kappa B-dependent gene expression in a manner dependent on the concentration of TPA.
Signal Transduction Laboratory, SRI International, Menlo Park, CA 94025, USA.
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K
Watanabe
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I
Kazakova
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M
Furniss
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SC
Miller
D002614:Chelating Agents; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics; D005786:Gene Expression Regulation; D015967:Gene Expression Regulation, Viral; D017930:Genes, Reporter; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000235:genetics*; D006801:Humans; D008670:Metals; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D011759:Pyrrolidines / Q000378:metabolism* / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism* / Q000494:pharmacology; D013859:Thiocarbamates / Q000378:metabolism* / Q000494:pharmacology; D013997:Time Factors; D018808:Transcription Factor AP-1 / Q000378:metabolism; D020298:U937 Cells
D002614:Chelating Agents; D008670:Metals; D016328:NF-kappa B; D011759:Pyrrolidines; D013859:Thiocarbamates; D018808:Transcription Factor AP-1; C020972:pyrrolidine dithiocarbamic acid; D015500:Chloramphenicol O-Acetyltransferase; D013755:Tetradecanoylphorbol Acetate