title: Comparison of apoptosis in wild-type and Fas-resistant cells: chemotherapy-induced apoptosis is not dependent on Fas/Fas ligand interactions.
abstract: The Fas/Fas ligand (FasL) pathway is widely involved in apoptotic cell death in lymphoid and nonlymphoid cells. It has recently been postulated that many chemotherapeutic agents also induce cell death by activating the Fas/FasL pathway. In the present study we compared apoptotic pathways induced by anti-Fas or chemotherapeutic agents in the Jurkat human T-cell leukemia line. Immunoblotting showed that treatment of wild-type Jurkat cells with anti-Fas or the topoisomerase II-directed agent etoposide resulted in proteolytic cleavage of precursors for the cysteine-dependent aspartate-directed proteases caspase-3 and caspase-7 and degradation of the caspase substrates poly(ADP-ribose) polymerase (PARP) and lamin B1. Likewise, affinity labeling with N-(N(alpha)-benzyloxycarbonylglutamyl-N(epsilon)-biotinyllysyl+ ++)aspartic acid [(2,6-dimethyl-benzoyl)oxy]methyl ketone [Z-EK(bio)D-amok] labeled the same five active caspase species after each treatment, suggesting that the same downstream apoptotic pathways have been activated by anti-Fas and etoposide. Treatment with ZB4, an antibody that inhibits Fas-mediated cell death, failed to block etoposide-induced apoptosis, raising the possibility that etoposide does not initiate apoptosis through Fas/FasL interactions. To further explore the relationship between Fas- and chemotherapy-induced apoptosis, Fas-resistant Jurkat cells were treated with various chemotherapeutic agents. Multiple independently derived Fas-resistant Jurkat lines underwent apoptosis that was indistinguishable from that of the Fas-sensitive parental cells after treatment with etoposide, doxorubicin, topotecan, cisplatin, methotrexate, staurosporine, or gamma-irradiation. These results indicate that antineoplastic treatments induce apoptosis through a Fas-independent pathway even though Fas- and chemotherapy-induced pathways converge on common downstream apoptotic effector molecules.
authors.affiliation: Department of Immunology, Mayo Clinic, Rochester, MN 55901, USA.
authors.forename: C M
authors.initials: CM
authors.lastname: Eischen
authors.forename: T J
authors.initials: TJ
authors.lastname: Kottke
authors.forename: L M
authors.initials: LM
authors.lastname: Martins
authors.forename: G S
authors.initials: GS
authors.lastname: Basi
authors.forename: J S
authors.initials: JS
authors.lastname: Tung
authors.forename: W C
authors.initials: WC
authors.lastname: Earnshaw
authors.forename: P J
authors.initials: PJ
authors.lastname: Leibson
authors.forename: S H
authors.initials: SH
authors.lastname: Kaufmann
mesh_terms: D000345:Affinity Labels; D000970:Antineoplastic Agents / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D001710:Biotin / Q000031:analogs & derivatives; D002166:Camptothecin / Q000031:analogs & derivatives / Q000494:pharmacology; D053148:Caspase 3; D053179:Caspase 7; D020169:Caspases; D002945:Cisplatin / Q000494:pharmacology; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005047:Etoposide / Q000494:pharmacology; D053222:Fas Ligand Protein; D005434:Flow Cytometry; D006801:Humans; D034921:Lamin Type B; D034882:Lamins; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000473:pathology; D008562:Membrane Glycoproteins / Q000502:physiology*; D008727:Methotrexate / Q000494:pharmacology; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000502:physiology; D009687:Nuclear Proteins / Q000378:metabolism; D009842:Oligopeptides; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D059005:Topoisomerase II Inhibitors; D019772:Topotecan; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000528:radiation effects; D019014:fas Receptor / Q000502:physiology*
chemical_list: D000345:Affinity Labels; D000970:Antineoplastic Agents; D000972:Antineoplastic Agents, Phytogenic; D004791:Enzyme Inhibitors; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D034921:Lamin Type B; D034882:Lamins; D008562:Membrane Glycoproteins; C107287:N-(N-(alpha)-benzyloxycarbonylglutamyl-(epsilon)-biotinyllysyl)aspartic acid ((2,6-dimethylbenzoyl)oxy)methyl ketone; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D009842:Oligopeptides; D059005:Topoisomerase II Inhibitors; D019014:fas Receptor; D005047:Etoposide; D001710:Biotin; D019772:Topotecan; D004317:Doxorubicin; D011065:Poly(ADP-ribose) Polymerases; C505407:CASP3 protein, human; C505520:CASP7 protein, human; D053148:Caspase 3; D053179:Caspase 7; D020169:Caspases; D003546:Cysteine Endopeptidases; D019311:Staurosporine; D002945:Cisplatin; D002166:Camptothecin; D008727:Methotrexate