title: Camptothecin- and etoposide-induced apoptosis in human leukemia cells is independent of cell death receptor-3 and -4 aggregation but accelerates tumor necrosis factor-related apoptosis-inducing ligand-mediated cell death.
abstract: During camptothecin- and etoposide (VP-16)-induced apoptosis in HL-60 cells, the expression level of cell death receptor-3 (DR3), cell death receptor-4 (DR4), and FAS remained mostly unchanged, whereas the expression of silencers of death domain (SODD) and FLICE inhibitory proteins, inhibitors of the cell death receptor signaling pathways, decreased substantially. By indirect immunofluorescence and immunoperoxidase imaging and with gel filtration column chromatography, we observed rapid aggregation at the cell surface and the appearance of high molecular weight protein complexes primarily involving DR3, and DR3 and DR4 after camptothecin and VP-16 treatment, respectively. Both drugs failed to rapidly promote FAS aggregation in these cells. The high expression level of SODD or of dominant negative forms of FADD (FADD-DN) and DAP3 (DAP3-DN), or of NH2-terminal deletion mutant of TRADD (TRADD-ND) achieved by transient transfection experiments, did not impair the kinetics of apoptosis after camptothecin and VP-16 treatment in HL-60 and U937 cells. Taken together, these observations suggested that camptothecin and VP-16 induced rapid aggregation of DR4 and DR3, but paradoxically, the importance of these events in signaling apoptosis is uncertain, because the kinetics of apoptosis were unaffected, even in the presence of a high expression level of SODD, FADD-DN, TRADD-ND, and DAP3-DN. However, camptothecin or VP-16 treatment in combination with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) substantially accelerated kinetics of apoptosis than treatment with camptothecin, VP-16, or TRAIL alone. In contrast, cotreatment of camptothecin or VP-16 with TWEAK or TL1A did not facilitate apoptosis in HL60 cells. These findings suggest that DR4 aggregation mediated by camptothecin or VP-16 could represent a mean that accelerates TRAIL-induced apoptosis.
authors.affiliation: Centre de recherche, Centre hospitalier de l'Université de Montréal-Hôpital Notre-Dame, and Institut du cancer de Montréal, Montréal, Quebec, Canada.
authors.forename: Stephane
authors.initials: S
authors.lastname: Bergeron
authors.forename: Myriam
authors.initials: M
authors.lastname: Beauchemin
authors.forename: Richard
authors.initials: R
authors.lastname: Bertrand
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D002166:Camptothecin / Q000008:administration & dosage; D005047:Etoposide / Q000008:administration & dosage; D053200:Fas-Associated Death Domain Protein; D017353:Gene Deletion; D005799:Genes, Dominant; D018922:HL-60 Cells; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D007938:Leukemia / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008024:Ligands; D008562:Membrane Glycoproteins / Q000378:metabolism*; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism*; D053219:Receptors, Tumor Necrosis Factor, Member 25; D053221:TNF-Related Apoptosis-Inducing Ligand; D000074050:TWEAK Receptor; D014162:Transfection; D053380:Tumor Necrosis Factor Ligand Superfamily Member 15; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D020298:U937 Cells
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C116906:BAG4 protein, human; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; C505533:FADD protein, human; D053200:Fas-Associated Death Domain Protein; D047908:Intracellular Signaling Peptides and Proteins; D008024:Ligands; D008562:Membrane Glycoproteins; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D053219:Receptors, Tumor Necrosis Factor, Member 25; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C506033:TNFRSF25 protein, human; C505653:TNFSF10 protein, human; C117026:TNFSF15 protein, human; D000074050:TWEAK Receptor; D053380:Tumor Necrosis Factor Ligand Superfamily Member 15; D047988:Tumor Necrosis Factor Receptor-Associated Peptides and Proteins; D014409:Tumor Necrosis Factor-alpha; D005047:Etoposide; D002166:Camptothecin