title: Adenovirus-mediated transfection of caspase-8 sensitizes hepatocellular carcinoma to TRAIL- and chemotherapeutic agent-induced cell death.
abstract: Caspase-8 belongs to the cysteine protease family and is known to be activated at the initial step in the cascade of TRAIL-induced apoptosis. The activation of procaspase-8 can be blocked by a relatively large amount of c-FLIP, which renders resistance to death receptor-mediated apoptosis in many types of cancer cells. To ask if extrinsic over-expression of caspase-8 contributes to the induction of apoptosis, we introduced the caspase-8 gene into HCC cells using an adenoviral (Adv) vector (Adv-Casp8). We demonstrated that Adv-Casp8 increased expression of active forms of caspase-8 in MOI-dependent manner. A large amount of Adv-Casp8 (MOI of 50) induced apoptosis significantly in HCC cells and resulted in downregulation of c-FLIP (in SK-Hep1, HLE, and HepG2 cells), XIAP, survivin, and Bcl-xL (in HLE cells) and dynamic release of cytochrome c and Smac from the mitochondria into the cytosol. On the other hand, a small amount of Adv-Casp8 (MOI of 10) causes a slight but detectable increase in the level of apoptosis with only a small effect on anti-apoptotic proteins and mitochondrial activation. However, small amounts of Adv-Casp8 augmented TRAIL- or chemotherapeutic agent-induced cell death (with an MOI of 10 or 20, respectively). These results suggest both that exogenous over-expression of caspase-8 by Adv-Casp8 may be essential for induction of HCC cell death and that the combination of Adv-Casp8 and TRAIL or chemotherapeutic agents could provide a useful strategy for treatment of HCC.
authors.affiliation: First Department of Internal Medicine, Mie University School of Medicine, Edobashi, 2-174, Tsu, Mie 514-8507, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Katsuya
authors.initials: K
authors.lastname: Shiraki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fuke
authors.forename: Tomoko
authors.initials: T
authors.lastname: Inoue
authors.forename: Kazumi
authors.initials: K
authors.lastname: Miyashita
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yamanaka
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakano
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000494:pharmacology; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; D006528:Carcinoma, Hepatocellular / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D053181:Caspase 8; D020169:Caspases / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D015870:Gene Expression; D005822:Genetic Vectors; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008113:Liver Neoplasms / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D008562:Membrane Glycoproteins / Q000494:pharmacology; D053221:TNF-Related Apoptosis-Inducing Ligand; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; D047908:Intracellular Signaling Peptides and Proteins; D008562:Membrane Glycoproteins; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; D014409:Tumor Necrosis Factor-alpha; C505530:CASP8 protein, human; D053181:Caspase 8; D020169:Caspases