Abstract
Immunostaining and EMSA revealed that NF-kappaB was activated strongly by TNF/IFN-alpha compared to TNF alone in a human colon adenocarcinoma cell line, RPMI4788. Although inhibition of activated NF-kappaB, by using an NF-kappaB decoy, reduced cell viability after treatment with TNF only, NF-kappaB decoy resulted in recovery of cell viability after TNF/IFN-alpha treatment. Caspase-3 activity was increased in cells induced by TNF/IFN-alpha, while suppression of caspase-3 activity was observed in cells transfected with NF-kappaB decoy and then treated by TNF/IFN-alpha. On the other hand, Fas expression was strongly enhanced by TNF/IFN-alpha, and inhibition of TNF/IFN-alpha-induced NF-kappaB activation, by using NF-kappaB decoy, decreased Fas expression. Cell viability and caspase-3 activity decreased in cells treated with TNF/IFN-alpha and anti-FasL antibody. Taken together, our findings suggest that activated NF-kappaB induced by the crosstalk between TNF and IFN-alpha is a novel pro-apoptotic signal acting via enhancement of Fas expression.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antibodies / pharmacology
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Apoptosis / drug effects
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Apoptosis / physiology*
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Carcinoma / drug therapy
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Carcinoma / genetics
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Carcinoma / metabolism*
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Caspase 3
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Caspases / drug effects
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Caspases / metabolism
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Cell Division / drug effects
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Cell Division / physiology
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Cell Survival / drug effects
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Cell Survival / physiology
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Colonic Neoplasms / drug therapy
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Colonic Neoplasms / genetics
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Colonic Neoplasms / metabolism*
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Drug Synergism
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Fas Ligand Protein
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Humans
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Interferon-alpha / metabolism
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Interferon-alpha / pharmacology*
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Membrane Glycoproteins / antagonists & inhibitors
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Membrane Glycoproteins / metabolism
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NF-kappa B / metabolism*
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Signal Transduction / drug effects
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Signal Transduction / physiology
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Tumor Cells, Cultured
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Tumor Necrosis Factor-alpha / metabolism
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Tumor Necrosis Factor-alpha / pharmacology*
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Up-Regulation / drug effects
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Up-Regulation / physiology
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fas Receptor / metabolism*
Substances
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Antibodies
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FASLG protein, human
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Fas Ligand Protein
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Interferon-alpha
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Membrane Glycoproteins
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NF-kappa B
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Tumor Necrosis Factor-alpha
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fas Receptor
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CASP3 protein, human
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Caspase 3
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Caspases