title: Tumor necrosis factor-related apoptosis-inducing ligand-induced death-inducing signaling complex and its modulation by c-FLIP and PED/PEA-15 in glioma cells.
abstract: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) can trigger apoptosis in some tumor cells but not other tumor cells. To explore the signal transduction events in TRAIL-triggered apoptosis and its modulation in nontransfected tumor cells, we analyzed TRAIL-induced death-inducing signaling complex (DISC) in TRAIL-sensitive and -resistant glioma cells. Caspase-8 and caspase-10 were recruited to the DISC, where they were proteolytically activated to initiate apoptosis in TRAIL-sensitive glioma cells. Caspase-8 and caspase-10 were also recruited to the DISC in TRAIL-resistant cells, but their further activation was inhibited by two antiapoptotic proteins termed cellular Fas-associated death domain-like interleukin-1beta-converting enzyme-inhibitory protein (c-FLIP) and phosphoprotein enriched in diabetes/phosphoprotein enriched in astrocytes-15kDa (PED/PEA-15). Both long and short forms of c-FLIP were recruited to the DISC, where the long form c-FLIP was cleaved to produce intermediate fragments. Of the three isoforms of PED/PEA-15 proteins, only the doubly phosphorylated form was expressed and recruited to the DISC in TRAIL-resistant cells, indicating that the phosphorylation status of PED/PEA-15 determines its recruitment in the cells. Treatment with calcium/calmodulin-dependent protein kinase inhibitor rescued TRAIL sensitivity in TRAIL-resistant cells, providing a potential new approach to sensitize the cells to TRAIL-induced apoptosis.
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Canada.
authors.forename: Chang
authors.initials: C
authors.lastname: Xiao
authors.forename: Bao Feng
authors.initials: BF
authors.lastname: Yang
authors.forename: Neda
authors.initials: N
authors.lastname: Asadi
authors.forename: Francesco
authors.initials: F
authors.lastname: Beguinot
authors.forename: Chunhai
authors.initials: C
authors.lastname: Hao
mesh_terms: D017209:Apoptosis / Q000502:physiology; D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D002352:Carrier Proteins / Q000378:metabolism / Q000502:physiology*; D053455:Caspase 10; D020169:Caspases / Q000378:metabolism; D005910:Glioma / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D019169:Jurkat Cells; D008562:Membrane Glycoproteins / Q000378:metabolism / Q000502:physiology*; D010750:Phosphoproteins / Q000378:metabolism / Q000502:physiology*; D010766:Phosphorylation; D053221:TNF-Related Apoptosis-Inducing Ligand; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000502:physiology*
chemical_list: D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; C092039:PEA15 protein, human; D010750:Phosphoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; D053455:Caspase 10; D020169:Caspases; C506438:CASP10 protein, human