title: Inhibition of caspases primes colon cancer cells for 5-fluorouracil-induced TNF-α-dependent necroptosis driven by RIP1 kinase and NF-κB.
abstract: Resistance towards the drug 5-fluorouracil (5-FU) is a key challenge in the adjuvant chemotherapy of colorectal cancer (CRC), and novel targeted approaches are required to improve the therapeutic outcome. Necroptosis is a recently discovered form of programmed cell death, which depends on receptor interacting protein 1 (RIP1) and particularly occurs under caspase-deficient conditions. The targeted induction of necroptosis represents a promising strategy to overcome apoptosis resistance in cancer. The aim of this study was to systematically explore the usage of pan-caspase inhibitors to sensitize resistant CRC cells for 5-FU. We found that pan-caspase inhibitors facilitated 5-FU-induced necroptosis, which was mediated by autocrine secretion of tumor necrosis factor α (TNF-α). TNF-α production was driven by nuclear factor κB (NF-κB) and required RIP1 kinase. In vivo xenograft experiments showed that the novel pan-caspase inhibitor IDN-7314 in combination with 5-FU synergistically blocked tumor growth. Ex vivo experiments with fresh human CRC tissue specimens further indicated that a subgroup of patients could benefit from combinatory treatment. Thereby, elevated levels of secreted TNF-α and expression of components of the necroptotic pathway might help to predict the sensitivity to pro-necroptotic therapies. Together, our results shed new light on the molecular regulation of necroptosis by NF-κB and RIP1. Moreover, we identify necroptotic cell death as an important effector mechanism of 5-FU-mediated anti-tumoral activity. On the basis of this study, we propose pan-caspase inhibitors as a novel approach in the adjuvant chemotherapy of CRC.
authors.affiliation: Institute of Pathology, University of Heidelberg, Heidelberg, Germany.|Molecular Tumor Pathology, German Cancer Research Center, Heidelberg, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Oliver Metzig
authors.affiliation: Institute of Pathology, University of Heidelberg, Heidelberg, Germany.|Molecular Tumor Pathology, German Cancer Research Center, Heidelberg, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Fuchs
authors.affiliation: Molecular Tumor Pathology, German Cancer Research Center, Heidelberg, Germany.
authors.forename: K E
authors.initials: KE
authors.lastname: Tagscherer
authors.affiliation: Cellular and Molecular Pathology, German Cancer Research Center, Heidelberg, Germany.
authors.forename: H-J
authors.initials: HJ
authors.lastname: Gröne
authors.affiliation: Institute of Pathology, University of Heidelberg, Heidelberg, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Schirmacher
authors.affiliation: Institute of Pathology, University of Heidelberg, Heidelberg, Germany.|Molecular Tumor Pathology, German Cancer Research Center, Heidelberg, Germany.|Institute of Pathology, University Medical Center Mainz, Mainz, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Roth
mesh_terms: D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism*; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000648:ultrastructure; D005472:Fluorouracil / Q000494:pharmacology*; D045325:HCT116 Cells; D019073:HT29 Cells; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D008819:Mice, Nude; D008854:Microscopy, Electron; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009336:Necrosis; D009842:Oligopeptides / Q000494:pharmacology; D034622:RNA Interference; D053422:Receptor-Interacting Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D047368:Tumor Burden / Q000187:drug effects / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
chemical_list: D000964:Antimetabolites, Antineoplastic; D016328:NF-kappa B; D009842:Oligopeptides; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; C517629:benzyloxycarbonyl-valyl-alanyl-aspartic acid; C506249:RIPK1 protein, human; D053422:Receptor-Interacting Protein Serine-Threonine Kinases; D020169:Caspases; D005472:Fluorouracil