Abstract
The expression of genes that regulate Fas-induced apoptosis has been examined in 10 human cultured colon carcinoma cell lines with defined and varied sensitivity to the cytolytic anti-Fas MoAb CH-11. Four lines demonstrated sensitivity to CH-11 (HT29, GC3/c1, TS-, Thy4), and six were resistant to the induction of apoptosis vis Fas. In nine lines expressing Fas, PCR-sequencing indicated that the death domain contained wt sequences. Downstream of Fas, expression of FADD/MORT1 and FLICE, essential components of the DISC, and negative regulators of Fas signalling including sFas, FAP-1 and Bcl-2, showed no correlation between levels of expression and sensitivity to Fas-mediated cytotoxicity. However, levels of the Fas antigen varied by >1000-fold, and correlated with CH-11 sensitivity. Following fourfold elevation in Fas expression in HT29 cells treated with interferon-gamma, a synergistic effect on Fas-mediated apoptosis was obtained when CH-11 and interferon-gamma were combined.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adaptor Proteins, Signal Transducing*
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Antibodies, Monoclonal / immunology
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Apoptosis / genetics*
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Carrier Proteins / genetics
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Caspase 8
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Caspase 9
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Caspases / genetics
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Cell Division / genetics
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Cell Survival / genetics
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Colonic Neoplasms / genetics
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Colonic Neoplasms / immunology
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Fas-Associated Death Domain Protein
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Gene Expression Regulation, Neoplastic
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Humans
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Interferon-gamma / pharmacology
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Protein Tyrosine Phosphatase, Non-Receptor Type 13
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Protein Tyrosine Phosphatases / genetics
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Proto-Oncogene Proteins c-bcl-2 / genetics
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RNA, Messenger / genetics
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Signal Transduction / genetics*
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Tumor Cells, Cultured
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fas Receptor / genetics*
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fas Receptor / immunology
Substances
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Adaptor Proteins, Signal Transducing
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Antibodies, Monoclonal
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Carrier Proteins
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FADD protein, human
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Fas-Associated Death Domain Protein
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Proto-Oncogene Proteins c-bcl-2
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RNA, Messenger
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fas Receptor
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Interferon-gamma
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PTPN13 protein, human
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Protein Tyrosine Phosphatase, Non-Receptor Type 13
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Protein Tyrosine Phosphatases
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CASP8 protein, human
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CASP9 protein, human
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Caspase 8
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Caspase 9
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Caspases