Abstract
Small-molecule library screening to find compounds that inhibit TNFalpha-induced, but not interleukin 1beta (IL-1beta)-induced, intercellular adhesion molecule 1 (ICAM-1) expression in lung epithelial cells identified a class of triazoloquinoxalines. These compounds not only inhibited the TNFalpha-induced nuclear factor kappaB (NFkappaB) survival pathway but also blocked death-pathway activation. Such dual activity makes them unique against other known NFkappaB-pathway inhibitors that inhibit only a subset of TNFalpha signals leading to increased TNFalpha-induced cytotoxicity. Interestingly, these compounds inhibited association of TNFalpha receptor (TNFalphaR) I with TNFalphaR-associated death domain protein (TRADD) and receptor interacting protein 1 (RIP1), the initial intracellular signaling event following TNFalpha stimulation. Further study showed that they blocked ligand-dependent internalization of the TNFalpha-TNFalphaR complex, thereby inhibiting most of the TNFalpha-induced cellular responses. Thus, compounds with a triazoloquinoxaline scaffold could be a valuable tool to investigate small molecule-based anti-TNFalpha therapies.
MeSH terms
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Apoptosis / drug effects*
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Apoptosis / physiology
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Cell Membrane / chemistry
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Cell Membrane / metabolism
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Enzyme Inhibitors / pharmacology*
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Epithelial Cells / cytology
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Epithelial Cells / pathology
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Gene Expression Regulation / genetics
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Gene Expression Regulation / physiology
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Intercellular Adhesion Molecule-1 / genetics
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Intercellular Adhesion Molecule-1 / metabolism*
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Lung / cytology
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Lung / pathology
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Quinoxalines / pharmacology*
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Receptor-Interacting Protein Serine-Threonine Kinases / genetics
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Receptor-Interacting Protein Serine-Threonine Kinases / metabolism*
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Receptors, Tumor Necrosis Factor, Type I / genetics
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Receptors, Tumor Necrosis Factor, Type I / metabolism*
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Signal Transduction / genetics
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Signal Transduction / physiology
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Small Molecule Libraries
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TNF Receptor-Associated Death Domain Protein / genetics
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TNF Receptor-Associated Death Domain Protein / metabolism*
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Triazoles / pharmacology*
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Tumor Necrosis Factor-alpha*
Substances
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Enzyme Inhibitors
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Quinoxalines
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Receptors, Tumor Necrosis Factor, Type I
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Small Molecule Libraries
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TNF Receptor-Associated Death Domain Protein
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Triazoles
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Tumor Necrosis Factor-alpha
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Intercellular Adhesion Molecule-1
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Receptor-Interacting Protein Serine-Threonine Kinases