title: Spontaneous tumor development in bone marrow-rescued DNA-PKcs(3A/3A) mice due to dysfunction of telomere leading strand deprotection.
abstract: Phosphorylation of the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) at the Thr2609 cluster is essential for its complete function in DNA repair and tissue stem cell homeostasis. This phenomenon is demonstrated by congenital bone marrow failure occurring in DNA-PKcs(3A/3A) mutant mice, which require bone marrow transplantation (BMT) to prevent early mortality. Surprisingly, an increased incidence of spontaneous tumors, especially skin cancer, was observed in adult BMT-rescued DNA-PKcs(3A/3A) mice. Upon further investigation, we found that spontaneous γH2AX foci occurred in DNA-PKcs(3A/3A) skin biopsies and primary keratinocytes and that these foci overlapped with telomeres during mitosis, indicating impairment of telomere replication and maturation. Consistently, we observed significantly elevated frequencies of telomere fusion events in DNA-PKcs(3A/3A) cells as compared with wild-type and DNA-PKcs-knockout cells. In addition, a previously identified DNA-PKcs Thr2609Pro mutation, found in breast cancer, also induces a similar impairment of telomere leading-end maturation. Taken together, our current analyses indicate that the functional DNA-PKcs T2609 cluster is required to facilitate telomere leading strand maturation and prevention of genomic instability and cancer development.
authors.affiliation: Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.|Department of Radiation Oncology, Sichuan Cancer Hospital, Chengdu, People's Republic of China.
authors.forename: S
authors.initials: S
authors.lastname: Zhang
authors.affiliation: Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.|Division of Molecular Pharmacology, Department of Pathophysiological and Therapeutic Science, Tottori University, Yonago, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Matsunaga
authors.affiliation: Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
authors.forename: Y-F
authors.initials: YF
authors.lastname: Lin
authors.affiliation: Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
authors.forename: B
authors.initials: B
authors.lastname: Sishc
authors.affiliation: Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
authors.forename: Z
authors.initials: Z
authors.lastname: Shang
authors.affiliation: Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
authors.forename: J
authors.initials: J
authors.lastname: Sui
authors.affiliation: Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
authors.forename: H-Y
authors.initials: HY
authors.lastname: Shih
authors.affiliation: Key Laboratory of Gene Engineering of the Ministry of Education, Cooperative Innovation Center for High Performance Computing, School of Life Sciences, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: The Jackson Laboratory, Sacramento, CA, USA.
authors.forename: O
authors.initials: O
authors.lastname: Foreman
authors.affiliation: Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Story
authors.affiliation: Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Chen
authors.affiliation: Division of Molecular Radiation Biology, Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA.
authors.forename: B P C
authors.initials: BP
authors.lastname: Chen
mesh_terms: D000818:Animals; D016026:Bone Marrow Transplantation; D002478:Cells, Cultured; D004249:DNA Damage; D051747:DNA-Activated Protein Kinase / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000502:physiology*; D042822:Genomic Instability; D006657:Histones / Q000032:analysis; D015603:Keratinocytes / Q000378:metabolism; D051379:Mice; D009369:Neoplasms / Q000209:etiology*; D009687:Nuclear Proteins / Q000502:physiology*; D016615:Telomere / Q000502:physiology*
chemical_list: D004268:DNA-Binding Proteins; C468783:H2AX protein, human; D006657:Histones; D009687:Nuclear Proteins; D051747:DNA-Activated Protein Kinase; C497264:Prkdc protein, mouse