title: Inhibiting DNA-PKCSradiosensitizes human osteosarcoma cells.
abstract: Osteosarcoma survival rate has not improved over the past three decades, and the debilitating side effects of the surgical treatment suggest the need for alternative local control approaches. Radiotherapy is largely ineffective in osteosarcoma, indicating a potential role for radiosensitizers. Blocking DNA repair, particularly by inhibiting the catalytic subunit of DNA-dependent protein kinase (DNA-PKCS), is an attractive option for the radiosensitization of osteosarcoma. In this study, the expression of DNA-PKCSin osteosarcoma tissue specimens and cell lines was examined. Moreover, the small molecule DNA-PKCSinhibitor, KU60648, was investigated as a radiosensitizing strategy for osteosarcoma cells in vitro. DNA-PKCSwas consistently expressed in the osteosarcoma tissue specimens and cell lines studied. Additionally, KU60648 effectively sensitized two of those osteosarcoma cell lines (143B cells by 1.5-fold and U2OS cells by 2.5-fold). KU60648 co-treatment also altered cell cycle distribution and enhanced DNA damage. Cell accumulation at the G2/M transition point increased by 55% and 45%, while the percentage of cells with >20 γH2AX foci were enhanced by 59% and 107% for 143B and U2OS cells, respectively. These results indicate that the DNA-PKCSinhibitor, KU60648, is a promising radiosensitizing agent for osteosarcoma.
authors.affiliation: Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55902, USA. Electronic address: mamo.tewodros@mayo.edu.
authors.forename: Tewodros
authors.initials: T
authors.lastname: Mamo
authors.affiliation: Department of Radiation Oncology, Mayo Clinic School of Graduate Medical Education, Mayo Clinic, Rochester, MN 55902, USA.
authors.forename: Ann C
authors.initials: AC
authors.lastname: Mladek
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic School of Graduate Medical Education, Mayo Clinic, Rochester, MN 55902, USA.
authors.forename: Kris L
authors.initials: KL
authors.lastname: Shogren
authors.affiliation: Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55902, USA.
authors.forename: Carl
authors.initials: C
authors.lastname: Gustafson
authors.affiliation: Department of Radiation Oncology, Mayo Clinic School of Graduate Medical Education, Mayo Clinic, Rochester, MN 55902, USA.
authors.forename: Shiv K
authors.initials: SK
authors.lastname: Gupta
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic School of Graduate Medical Education, Mayo Clinic, Rochester, MN 55902, USA.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Riester
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic School of Graduate Medical Education, Mayo Clinic, Rochester, MN 55902, USA.
authors.forename: Avudaiappan
authors.initials: A
authors.lastname: Maran
authors.affiliation: Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine and Millennium Institute on Immunology and Immunotherapy, University of Chile, Santiago, Chile.
authors.forename: Mario
authors.initials: M
authors.lastname: Galindo
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic School of Graduate Medical Education, Mayo Clinic, Rochester, MN 55902, USA; Department of Biomedical Engineering and Physiology, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55902, USA.
authors.forename: Andre J
authors.initials: AJ
authors.lastname: van Wijnen
authors.affiliation: Department of Radiation Oncology, Mayo Clinic School of Graduate Medical Education, Mayo Clinic, Rochester, MN 55902, USA.
authors.forename: Jann N
authors.initials: JN
authors.lastname: Sarkaria
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic School of Graduate Medical Education, Mayo Clinic, Rochester, MN 55902, USA; Department of Biomedical Engineering and Physiology, Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55902, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Yaszemski
mesh_terms: D001859:Bone Neoplasms / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D045744:Cell Line, Tumor; D002867:Chromones / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D004249:DNA Damage; D051747:DNA-Activated Protein Kinase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects / Q000528:radiation effects; D005720:Gamma Rays / Q000627:therapeutic use; D015972:Gene Expression Regulation, Neoplastic; D006657:Histones / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D012516:Osteosarcoma / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D047428:Protein Kinase Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D011838:Radiation-Sensitizing Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D017423:Sequence Analysis, RNA
chemical_list: D002867:Chromones; C468783:H2AX protein, human; D006657:Histones; D009687:Nuclear Proteins; D047428:Protein Kinase Inhibitors; D011838:Radiation-Sensitizing Agents; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human
keywords: DNA-PK; DNA-PKcs; KU60648; Osteosarcoma; Radiosensitizers; Radiotherapy