Negative regulation of Fas-mediated apoptosis by FAP-1 in human cancer cells.
FAP-1 (Fas-associated phosphatase-1) was previously identified as a protein that associates with a negative regulatory domain (C-terminal 15 amino acids) of Fas using the yeast 2-hybrid system. Functional analysis indicated that FAP-1 expression correlates with resistance to Fas-induced apoptosis in human cancer cells. We first generated anti-FAP-1 polyclonal antibody and confirmed the interaction of FAP-1 and Fas in vivo. FAP-1 interacted with wild-type, but not mutant, Fas (tPLV) in 293T cells after transfecting FAP-1 and Fas or its mutant. To investigate the functional role of FAP-1 in Fas-mediated signal transduction, we established stable transfectants of FAP-1 in 3 human cancer cell lines. Apoptosis assays demonstrated that cancer cells over-expressing FAP-1 increased the resistance to Fas-induced apoptosis by the anti-Fas antibody CH-11 in contrast with the wild types or the vector-transfected cells. In addition, FAP-1 regulated the activity of both caspases 3 and 8. Our data indicate a functional role for FAP-1 as a negative regulator of Fas-mediated apoptosis in human cancer cells and suggest that an additional signal-transducing molecule may be required for complete suppression of Fas-mediated apoptosis.
Department of Otolaryngology/Head and Neck Surgery, Columbia University, New York, New York, USA.
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Li
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Kanki
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Hachiya
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Ohyama
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Irie
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Tang
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Mukai
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T
Sato
D000906:Antibodies / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology*; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D006801:Humans; D019169:Jurkat Cells / Q000378:metabolism / Q000473:pathology; D009363:Neoplasm Proteins / Q000235:genetics / Q000276:immunology / Q000502:physiology; D011233:Precipitin Tests; D054645:Protein Phosphatase 1; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D014162:Transfection; D014407:Tumor Cells, Cultured; D019014:fas Receptor / Q000276:immunology / Q000502:physiology*
D000906:Antibodies; D002352:Carrier Proteins; D061945:Caspase Inhibitors; D009363:Neoplasm Proteins; D019014:fas Receptor; D054645:Protein Phosphatase 1; C516742:PTPN13 protein, human; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; D017027:Protein Tyrosine Phosphatases; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases