title: Role of antiapoptotic proteins in tumor necrosis factor-related apoptosis-inducing ligand and cisplatin-augmented apoptosis.
abstract: OBJECTIVE
  The purpose of this study was to examine the effect of combined treatment with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and cisplatin in human head and neck squamous cell carcinoma. HNSCC-6 cells were treated with 0.1-1 micro g/ml TRAIL and/or 1-10 micro g/ml cisplatin for 24 h.
  
  
  RESULTS
  TRAIL alone or cisplatin alone caused minimal cytotoxicity. The combination of TRAIL and cisplatin synergistically enhanced apoptotic death, caspase-8 and caspase-3 activation, as well as poly(ADP-ribose) polymerase cleavage. However, the total cellular levels and the surface expression of TRAIL receptor proteins, such as death receptors 4 and 5 and decoy receptors 2 and 1, were not significantly changed by treatment with TRAIL and cisplatin. Interestingly, the level of the short form of Fas-associated death domain-like interleukin-1beta-converting enzyme-inhibitory protein (FLIP(S)) but not the long form of Fas-associated death domain-like interleukin-1beta-converting enzyme-inhibitory protein was reduced through cleavage. Benzyloxycarbonyl-Asp-Glu-Val-Asp-fluoromethylketone a caspase-3 inhibitor, blocked the cleavage of FLIP(S) and caspase-3 activation. Overexpression of FLIP(S) protected cells from apoptotic death and FLIP(S) cleavage during treatment with TRAIL in combination with cisplatin.
  
  
  CONCLUSIONS
  These results suggest that caspase-3 is responsible for FLIP(S) cleavage, and the cleavage of FLIP(S) is one of facilitating factors for TRAIL-induced apoptotic death.
authors.affiliation: Department of Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania, 15213, USA.
authors.forename: Jin H
authors.initials: JH
authors.lastname: Kim
authors.forename: Mubasshir
authors.initials: M
authors.lastname: Ajaz
authors.forename: Anna
authors.initials: A
authors.lastname: Lokshin
authors.forename: Yong J
authors.initials: YJ
authors.lastname: Lee
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D002294:Carcinoma, Squamous Cell / Q000188:drug therapy* / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D002945:Cisplatin / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D058851:GPI-Linked Proteins; D005822:Genetic Vectors; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins / Q000627:therapeutic use*; D008565:Membrane Proteins / Q000378:metabolism; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism; D053320:Receptors, Tumor Necrosis Factor, Member 10c; D011994:Recombinant Proteins / Q000378:metabolism / Q000627:therapeutic use; D053221:TNF-Related Apoptosis-Inducing Ligand; D013997:Time Factors; D014407:Tumor Cells, Cultured; D053319:Tumor Necrosis Factor Decoy Receptors; D014409:Tumor Necrosis Factor-alpha / Q000627:therapeutic use*
chemical_list: D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; D002352:Carrier Proteins; D004791:Enzyme Inhibitors; D058851:GPI-Linked Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D012333:RNA, Messenger; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D018124:Receptors, Tumor Necrosis Factor; D053320:Receptors, Tumor Necrosis Factor, Member 10c; D011994:Recombinant Proteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C105190:TNFRSF10A protein, human; C505639:TNFRSF10B protein, human; C108661:TNFRSF10C protein, human; C451501:TNFRSF10D protein, human; C505653:TNFSF10 protein, human; D053319:Tumor Necrosis Factor Decoy Receptors; D014409:Tumor Necrosis Factor-alpha; D011065:Poly(ADP-ribose) Polymerases; C505407:CASP3 protein, human; C505530:CASP8 protein, human; D053148:Caspase 3; D053181:Caspase 8; D020169:Caspases; D002945:Cisplatin