title: Apoptosis induction by epigallocatechin gallate involves its binding to Fas.
abstract: Epigallocatechin gallate (EGCG) is known to induce apoptosis in various types of tumor cells, but the precise mechanism by which EGCG induces apoptosis remains to be elucidated. The Fas-Fas ligand system is one of the major pathways operating in the apoptotic cascade. The aim of this study was to examine the possibility that EGCG-binding to Fas triggers the Fas-mediated apoptosis. The EGCG treatment of human monocytic leukemia U937 cells resulted in elevation of caspase 8 activity and fragmentation of caspase 8. The DNA ladder formation caused by the EGCG treatment was inhibited by the caspase 8 inhibitor. These findings suggested the involvement of the Fas-mediated cascade in the EGCG-induced apoptosis in U937 cells. Affinity chromatography revealed the binding between EGCG and Fas. Thus, the results suggest that EGCG-binding to Fas, presumably on the cell surface, triggers the Fas-mediated apoptosis in U937 cells.
authors.affiliation: School of Food and Nutritional Sciences, University of Shizuoka, Yada, Shizuoka, 422-8526, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Hayakawa
authors.forename: K
authors.initials: K
authors.lastname: Saeki
authors.forename: M
authors.initials: M
authors.lastname: Sazuka
authors.forename: Y
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Y
authors.initials: Y
authors.lastname: Shoji
authors.forename: T
authors.initials: T
authors.lastname: Ohta
authors.forename: K
authors.initials: K
authors.lastname: Kaji
authors.forename: A
authors.initials: A
authors.lastname: Yuo
authors.forename: M
authors.initials: M
authors.lastname: Isemura
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D053181:Caspase 8; D053453:Caspase 9; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology; D002846:Chromatography, Affinity; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D005434:Flow Cytometry; D006801:Humans; D011485:Protein Binding / Q000187:drug effects / Q000502:physiology; D020298:U937 Cells; D019014:fas Receptor / Q000378:metabolism*
chemical_list: D061945:Caspase Inhibitors; D015853:Cysteine Proteinase Inhibitors; D019014:fas Receptor; D002392:Catechin; C045651:epigallocatechin gallate; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases