title: Cytokine regulation of human intestinal primary epithelial cell susceptibility to Fas-mediated apoptosis.
abstract: The regulatory mechanisms of nontransformed intestinal epithelial cell apoptosis have not been thoroughly investigated. We determined the susceptibility and mechanism of Fas-mediated apoptosis in nontransformed human intestinal epithelial cells (HIPEC) in the presence and absence of inflammatory cytokines. Despite ample expression of Fas, HIPEC were relatively insensitive to Fas-mediated apoptosis in that agonist anti-Fas antibody (CH11) induced a <25% increase in HIPEC apoptosis. Pretreatment of HIPEC with interferon (IFN)-gamma, but not tumor necrosis factor-alpha or granulocyte-macrophage colony-stimulating factor, significantly increased CH11-induced apoptosis of these cells without increasing Fas expression. Increased apoptosis correlated with increased caspase 3 activation but not expression of procaspase 3. Also, there was a significant delay in the onset of Fas-mediated apoptosis in HIPEC, which correlated with the generation of an activated caspase 3 p22/20 subunit. HIPEC required both initiator caspases 8 and 9 activity but expressed significantly less of the zymogen form of these caspases than did control cells. IFN-gamma-mediated sensitization of HIPEC occurred upstream of caspase 9 activation and correlated with a small increase in procaspase 8 expression (<1-fold increase) and a significant increase in expression of an intermediate form (p35) of caspase 4 (3.3-fold increase).
authors.affiliation: Gastrointestinal Research Laboratory, Division of Gastroenterology Hepatology and Nutrition, Department of Medicine, Winthrop-University Hospital, Mineola, New York 11501, USA.
authors.forename: Carla A
authors.initials: CA
authors.lastname: Martin
authors.forename: Asit
authors.initials: A
authors.lastname: Panja
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D002352:Carrier Proteins / Q000378:metabolism; D020170:Caspase 1 / Q000378:metabolism; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D053471:Caspases, Initiator; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004792:Enzyme Precursors / Q000378:metabolism; D053200:Fas-Associated Death Domain Protein; D019073:HT29 Cells; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins; D007371:Interferon-gamma / Q000494:pharmacology*; D007413:Intestinal Mucosa / Q000166:cytology* / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D019169:Jurkat Cells; D011506:Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019014:fas Receptor / Q000276:immunology / Q000378:metabolism*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal; D000970:Antineoplastic Agents; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; D002352:Carrier Proteins; D015853:Cysteine Proteinase Inhibitors; D004792:Enzyme Precursors; C505533:FADD protein, human; D053200:Fas-Associated Death Domain Protein; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor; D007371:Interferon-gamma; C505407:CASP3 protein, human; C093516:CASP4 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; D053471:Caspases, Initiator; D020170:Caspase 1