title: Loss of caspase-3 sensitizes colon cancer cells to genotoxic stress via RIP1-dependent necrosis.
abstract: Caspase-3 is the best known executioner caspase in apoptosis. We generated caspase-3 knockout (C3KO) and knockdown human colorectal cancer cells, and found that they are unexpectedly sensitized to DNA-damaging agents including 5-fluorouracil (5-FU), etoposide, and camptothecin. C3KO xenograft tumors also displayed enhanced therapeutic response and cell death to 5-FU. C3KO cells showed intact apoptosis and activation of caspase-7 and -9, impaired processing of caspase-8, and induction of necrosis in response to DNA-damaging agents. This form of necrosis is associated with HMGB1 release and ROS production, and suppressed by genetic or pharmacological inhibition of RIP1, MLKL1, or caspase-8, but not inhibitors of pan-caspases or RIP3. 5-FU treatment led to the formation of a z-VAD-resistant pro-caspase-8/RIP1/FADD complex, which was strongly stabilized by caspase-3 KO. These data demonstrate a key role of caspase-3 in caspase-8 processing and suppression of DNA damage-induced necrosis, and provide a potentially novel way to chemosensitize cancer cells.
authors.affiliation: 1] Department of Pathology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA, USA [2] University of Pittsburgh Cancer Institute, Hillman Cancer Center Research Pavilion, 5117 Centre Ave., Pittsburgh, PA, USA.
authors.forename: M F
authors.initials: MF
authors.lastname: Brown
authors.affiliation: 1] Department of Pathology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA, USA [2] University of Pittsburgh Cancer Institute, Hillman Cancer Center Research Pavilion, 5117 Centre Ave., Pittsburgh, PA, USA.
authors.forename: B J
authors.initials: BJ
authors.lastname: Leibowitz
authors.affiliation: 1] University of Pittsburgh Cancer Institute, Hillman Cancer Center Research Pavilion, 5117 Centre Ave., Pittsburgh, PA, USA [2] Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA, USA.
authors.forename: D
authors.initials: D
authors.lastname: Chen
authors.affiliation: 1] Department of Pathology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA, USA [2] University of Pittsburgh Cancer Institute, Hillman Cancer Center Research Pavilion, 5117 Centre Ave., Pittsburgh, PA, USA.
authors.forename: K
authors.initials: K
authors.lastname: He
authors.affiliation: 1] University of Pittsburgh Cancer Institute, Hillman Cancer Center Research Pavilion, 5117 Centre Ave., Pittsburgh, PA, USA [2] Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA, USA.
authors.forename: F
authors.initials: F
authors.lastname: Zou
authors.affiliation: 1] University of Pittsburgh Cancer Institute, Hillman Cancer Center Research Pavilion, 5117 Centre Ave., Pittsburgh, PA, USA [2] Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA, USA.
authors.forename: R W
authors.initials: RW
authors.lastname: Sobol
authors.affiliation: 1] Department of Pathology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA, USA [2] University of Pittsburgh Cancer Institute, Hillman Cancer Center Research Pavilion, 5117 Centre Ave., Pittsburgh, PA, USA.
authors.forename: D
authors.initials: D
authors.lastname: Beer-Stolz
authors.affiliation: 1] University of Pittsburgh Cancer Institute, Hillman Cancer Center Research Pavilion, 5117 Centre Ave., Pittsburgh, PA, USA [2] Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA, USA.
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.affiliation: 1] Department of Pathology, University of Pittsburgh School of Medicine, 5117 Centre Ave., Pittsburgh, PA, USA [2] University of Pittsburgh Cancer Institute, Hillman Cancer Center Research Pavilion, 5117 Centre Ave., Pittsburgh, PA, USA.
authors.forename: J
authors.initials: J
authors.lastname: Yu
mesh_terms: D053148:Caspase 3 / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism; D016923:Cell Death / Q000502:physiology; D003110:Colonic Neoplasms / Q000201:enzymology* / Q000235:genetics*; D004249:DNA Damage; D045325:HCT116 Cells; D057809:HEK293 Cells; D019073:HT29 Cells; D006801:Humans; D028861:Nuclear Pore Complex Proteins / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: C119724:AGFG1 protein, human; D028861:Nuclear Pore Complex Proteins; D016601:RNA-Binding Proteins; D053148:Caspase 3