title: 5-Aminoimidazole-4-carboxamide riboside sensitizes TRAIL- and TNF{alpha}-induced cytotoxicity in colon cancer cells through AMP-activated protein kinase signaling.
abstract: Death receptor-mediated tumor cell death, either alone or in combination with other anticancer drugs, is considered as a new strategy for anticancer therapy. In this study, we have investigated the effects and molecular mechanisms of 5-aminoimidazole-4-carboxamide riboside [AICAR; a pharmacologic activator of AMP-activated protein kinase (AMPK)] in sensitizing tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL)- and TNFalpha-induced apoptosis of human colon cancer HCT116 cells. The cytotoxic action of AICAR requires AMPK activation and may occur at various stages of apoptotic pathways. AICAR cotreatment with either TRAIL or TNFalpha enhances activities of caspase-8, caspase-9, and caspase-3; down-regulates the antiapoptotic protein Bcl-2; increases the cleavage of Bid and results in the decrease of mitochondrial membrane potential; potentiates activation of p38 and c-Jun NH(2)-terminal kinase; and inhibits nuclear factor-kappaB activity. In addition, this sensitized cell apoptosis was neither observed in p53-null HCT116 cells nor affected by the cotreatment with mevalonate. In summary, we have developed a novel strategy of combining AICAR with TRAIL for the treatment of colon cancer cells. The sensitization effect of AICAR in cell apoptosis was mediated through AMPK pathway, requires p53 activity, and involves mitochondria-dependent apoptotic cascades, p38 and c-Jun NH(2)-terminal kinase.
authors.affiliation: Department of Pharmacology, College of Medicine, National Taiwan University, Room 1119, No. 1, Sec. 1, Jen-Ai Road, Taipei, Taiwan.
authors.forename: Rong-Ying
authors.initials: RY
authors.lastname: Su
authors.forename: Yee
authors.initials: Y
authors.lastname: Chao
authors.forename: Tsai-Yu
authors.initials: TY
authors.lastname: Chen
authors.forename: Duen-Yi
authors.initials: DY
authors.lastname: Huang
authors.forename: Wan-Wan
authors.initials: WW
authors.lastname: Lin
mesh_terms: D055372:AMP-Activated Protein Kinases; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives* / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D002453:Cell Cycle; D045744:Cell Line, Tumor; D002470:Cell Survival; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000473:pathology*; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D009097:Multienzyme Complexes / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012263:Ribonucleosides / Q000494:pharmacology*; D015398:Signal Transduction; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism*; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D009097:Multienzyme Complexes; D016328:NF-kappa B; D012263:Ribonucleosides; D053221:TNF-Related Apoptosis-Inducing Ligand; D014409:Tumor Necrosis Factor-alpha; D000620:Aminoimidazole Carboxamide; C011651:acadesine; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases