Abstract
Downregulation of MHC Class I antigens has been observed in many cancers and usually results from a decreased gene transcription. A reporter CAT gene dependent on the MHC Class I kappaB site or on a longer promoter is transactivated by NF-kappaB complexes containing p65 or RelB. p100 as well as IkappaB-alpha are potent inhibitors of this transcription and p100 sequesters RelB and p65 complexes in the cytoplasm of breast cancer cells. However, although p100 is highly expressed in a number of breast cancer cell lines, MHC Class I antigen expression was observed on all the cell lines we analysed and could be further induced by stimulation with the cytokines IFN-gamma or TNF-alpha. Stable transfection of a unresponsive mutated IkappaB-alpha Ser 32-36 expression vector showed that TNF-alpha induced MHC Cl I expression in an NF-kappaB-dependent way while IFN-gamma did it independently of any NF-kappaB activation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Antineoplastic Agents / pharmacology
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Binding Sites / genetics
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Breast Neoplasms / genetics*
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Breast Neoplasms / pathology
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Cytoplasm / chemistry
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Cytoplasm / metabolism
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DNA-Binding Proteins / pharmacology
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Gene Expression / drug effects
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Gene Expression / genetics
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Gene Expression Regulation / drug effects
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Gene Expression Regulation, Neoplastic
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Histocompatibility Antigens Class I / drug effects
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Histocompatibility Antigens Class I / genetics*
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Histocompatibility Antigens Class I / metabolism
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Humans
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I-kappa B Proteins*
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Interferon-gamma / pharmacology
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NF-KappaB Inhibitor alpha
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NF-kappa B / genetics
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NF-kappa B / pharmacology
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NF-kappa B / physiology*
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Promoter Regions, Genetic / genetics
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Proto-Oncogene Proteins*
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Recombinant Proteins / genetics
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Transcription Factor RelB
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Transcription Factors / genetics
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Transcription Factors / metabolism
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Transcriptional Activation / genetics
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Tumor Cells, Cultured / cytology
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Tumor Cells, Cultured / drug effects
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Tumor Cells, Cultured / metabolism
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Tumor Necrosis Factor-alpha / pharmacology
Substances
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Antineoplastic Agents
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DNA-Binding Proteins
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Histocompatibility Antigens Class I
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I-kappa B Proteins
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NF-kappa B
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NFKBIA protein, human
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Proto-Oncogene Proteins
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RELB protein, human
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Recombinant Proteins
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Transcription Factors
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Tumor Necrosis Factor-alpha
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NF-KappaB Inhibitor alpha
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Transcription Factor RelB
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Interferon-gamma