title: γ-H2AX kinetics as a novel approach to high content screening for small molecule radiosensitizers.
abstract: BACKGROUND
  Persistence of γ-H2AX after ionizing radiation (IR) or drug therapy is a robust reporter of unrepaired DNA double strand breaks in treated cells.
  
  
  METHODS
  DU-145 prostate cancer cells were treated with a chemical library ±IR and assayed for persistence of γ-H2AX using an automated 96-well immunocytochemistry assay at 4 hours after treatment. Hits that resulted in persistence of γ-H2AX foci were tested for effects on cell survival. The molecular targets of hits were validated by molecular, genetic and biochemical assays and in vivo activity was tested in a validated Drosophila cancer model.
  
  
  RESULTS
  We identified 2 compounds, MS0019266 and MS0017509, which markedly increased persistence of γ-H2AX, apoptosis and radiosensitization in DU-145 cells. Chemical evaluation demonstrated that both compounds exhibited structurally similar and biochemical assays confirmed that these compounds inhibit ribonucleotide reductase. DNA microarray analysis and immunoblotting demonstrates that MS0019266 significantly decreased polo-like kinase 1 gene and protein expression. MS0019266 demonstrated in vivo antitumor activity without significant whole organism toxicity.
  
  
  CONCLUSIONS
  MS0019266 and MS0017509 are promising compounds that may be candidates for further development as radiosensitizing compounds as inhibitors of ribonucleotide reductase.
authors: Department of Radiation Oncology, Mount Sinai School of Medicine, New York, New York, United States of America.
authors: Shibo
authors: S
authors: Fu
authors: Ying
authors: Y
authors: Yang
authors: Tirtha K
authors: TK
authors: Das
authors: Das
authors: D
authors: Tirtha
authors: Yun
authors: Y
authors: Yen
authors: Bing-sen
authors: BS
authors: Zhou
authors: Ming-Ming
authors: MM
authors: Zhou
authors: Michael
authors: M
authors: Ohlmeyer
authors: Eric C
authors: EC
authors: Ko
authors: Ross
authors: R
authors: Cagan
authors: Barry S
authors: BS
authors: Rosenstein
authors: Shu-hsia
authors: SH
authors: Chen
authors: Johnny
authors: J
authors: Kao
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002453:Cell Cycle / Q000187:drug effects / Q000528:radiation effects; D018797:Cell Cycle Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000473:pathology; D004247:DNA / Q000096:biosynthesis; D004249:DNA Damage; D004260:DNA Repair / Q000187:drug effects / Q000528:radiation effects; D004195:Disease Models, Animal; D004331:Drosophila melanogaster / Q000187:drug effects / Q000378:metabolism; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D005123:Eye / Q000187:drug effects / Q000473:pathology / Q000528:radiation effects / Q000648:ultrastructure; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000528:radiation effects; D006657:Histones / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D011839:Radiation, Ionizing; D011838:Radiation-Sensitizing Agents / Q000008:administration & dosage / Q000032:analysis* / Q000494:pharmacology*; D012264:Ribonucleotide Reductases / Q000037:antagonists & inhibitors / Q000378:metabolism; D054852:Small Molecule Libraries / Q000008:administration & dosage / Q000032:analysis* / Q000494:pharmacology*; D000097869:Polo-Like Kinase 1
chemical_list: D018797:Cell Cycle Proteins; D004247:DNA; D006657:Histones; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D011838:Radiation-Sensitizing Agents; D012264:Ribonucleotide Reductases; D054852:Small Molecule Libraries; D000097869:Polo-Like Kinase 1; C468783:H2AX protein, human