title: The Myc-evoked DNA damage response accounts for treatment resistance in primary lymphomas in vivo.
abstract: In addition to the ARF/p53 pathway, the DNA damage response (DDR) has been recognized as another oncogene-provoked anticancer barrier in early human tumorigenesis leading to apoptosis or cellular senescence. DDR mutations may promote tumor formation, but their impact on treatment outcome remains unclear. In this study, we generated ataxia telangiectasia mutated (Atm)-proficient and -deficient B-cell lymphomas in Emu-myc transgenic mice to examine the role of DDR defects in lymphomagenesis and treatment sensitivity. Atm inactivation accelerated development of lymphomas, and their DNA damage checkpoint defects were virtually indistinguishable from those observed in Atm+/+-derived lymphomas that spontaneously inactivated the proapoptotic Atm/p53 cascade in response to Myc-evoked reactive oxygen species (ROS). Importantly, acquisition of DDR defects, but not selection against the ARF pathway, could be prevented by lifelong exposure to the ROS scavenger N-acetylcysteine (NAC) in vivo. Following anticancer therapy, DDR-compromised lymphomas displayed apoptotic but, surprisingly, no senescence defects and achieved a much poorer long-term outcome when compared with DDR-competent lymphomas treated in vivo. Hence, Atm eliminates preneoplastic lesions by converting oncogenic signaling into apoptosis, and selection against an Atm-dependent response promotes formation of lymphomas with predetermined treatment insensitivity.
authors.affiliation: Charité-Humboldt University, Campus Virchow, Department of Hematology/Oncology, Berlin, Germany.
authors.forename: Maurice
authors.initials: M
authors.lastname: Reimann
authors.forename: Christoph
authors.initials: C
authors.lastname: Loddenkemper
authors.forename: Cornelia
authors.initials: C
authors.lastname: Rudolph
authors.forename: Ines
authors.initials: I
authors.lastname: Schildhauer
authors.forename: Bianca
authors.initials: B
authors.lastname: Teichmann
authors.forename: Harald
authors.initials: H
authors.lastname: Stein
authors.forename: Brigitte
authors.initials: B
authors.lastname: Schlegelberger
authors.forename: Bernd
authors.initials: B
authors.lastname: Dörken
authors.forename: Clemens A
authors.initials: CA
authors.lastname: Schmitt
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000378:metabolism; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D019008:Drug Resistance, Neoplasm / Q000235:genetics*; D005434:Flow Cytometry; D018014:Gene Transfer Techniques; D016259:Genes, myc; D015151:Immunoblotting; D016393:Lymphoma, B-Cell / Q000188:drug therapy / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species / Q000494:pharmacology; D014161:Transduction, Genetic; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: C417743:Cdkn2a protein, mouse; D018797:Cell Cycle Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004268:DNA-Binding Proteins; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D017346:Protein Serine-Threonine Kinases