title: Immunosuppressive leflunomide metabolite (A77 1726) blocks TNF-dependent nuclear factor-kappa B activation and gene expression.
abstract: Leflunomide is a novel immunosuppressive and antiinflammatory agent currently being tested for treatment of autoimmune diseases and transplant rejection. NF-kappa B is a transcription factor activated in response to a wide variety of inflammatory stimuli, including TNF, but whether leflunomide blocks NF-kappa B activation is not known. In the present report we demonstrate that treatment of a human T cell line (Jurkat) with leflunomide blocks TNF-mediated NF-kappa B activation in a dose- and time-dependent manner, with maximum inhibition at 5-10 microM. Inhibition was not restricted to TNF-induced activation, because leflunomide also inhibited NF-kappa B activation induced by other inflammatory agents, including phorbol ester, LPS, H2O2, okadaic acid, and ceramide. Leflunomide blocked the degradation of I kappa B alpha and subsequent nuclear translocation of the p65 subunit, steps essential for NF-kappa B activation. This correlated with inhibition of dual specificity-mitogen-activated protein kinase kinase as well as an Src protein tyrosine kinase, p56lck, by leflunomide. Reducing agents did not reverse the effect of leflunomide. Leflunomide also suppressed the TNF-activated NF-kappa B-dependent reporter gene expression. Our results thus indicate that leflunomide is a potent inhibitor of NF-kappa B activation induced by a wide variety of inflammatory stimuli, and this provides the molecular basis for its anti-inflammatory and immunosuppressive effects.
authors.affiliation: Cytokine Research Laboratory, Department of Molecular Oncology, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Manna
authors.forename: B B
authors.initials: BB
authors.lastname: Aggarwal
mesh_terms: D000814:Aniline Compounds / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002518:Ceramides / Q000037:antagonists & inhibitors / Q000494:pharmacology; D015500:Chloramphenicol O-Acetyltransferase / Q000037:antagonists & inhibitors / Q000235:genetics; D003437:Crotonates; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D004229:Dithiothreitol / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology*; D019450:Genes, MDR / Q000187:drug effects; D017930:Genes, Reporter / Q000187:drug effects; D051863:Host Cell Factor C1; D006801:Humans; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors / Q000494:pharmacology; D006885:Hydroxybutyrates / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D020672:I-kappa B Proteins; D007166:Immunosuppressive Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D007555:Isoxazoles / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology*; D000077339:Leflunomide; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors / Q000494:pharmacology; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000037:antagonists & inhibitors / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D052002:NF-kappa B p50 Subunit; D009570:Nitriles; D050811:Octamer Transcription Factor-1; D019319:Okadaic Acid / Q000037:antagonists & inhibitors / Q000494:pharmacology; D011485:Protein Binding / Q000187:drug effects; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000037:antagonists & inhibitors / Q000494:pharmacology; D014052:Toluidines; D018808:Transcription Factor AP-1 / Q000378:metabolism; D051996:Transcription Factor RelA; D014157:Transcription Factors / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors* / Q000502:physiology