title: The dominant negative mutant Artemis enhances tumor cell radiosensitivity.
abstract: BACKGROUND
  Tumor radioresistance often leads to treatment failure during radiotherapy. New strategies like developing radiosensitizer are clinically important. Intervention with DNA double-strand break repair is an effective way to modulate tumor cell radiosensitivity. This study focused on the mutant Artemis fragment-enhanced radiosensitivity of human cervical cancer cells.
  
  
  METHODS
  We constructed two pEGFP-C1-based eukaryotic expression vectors encoding full-length and the mutant Artemis fragment (D37N-413aa), respectively. HeLa cells were stably transfected with these plasmids or vector. Cell survival was measured by the clonogenic assay. The γH2AX foci assay was used to monitor DNA repair after irradiation. Co-immunoprecipitation and Western blot analysis were performed to study protein interaction and phosphorylation of Artemis.
  
  
  RESULTS
  Expression of the mutant Artemis fragment (D37N-413aa) delayed DNA DSB rejoining after irradiation, thereby enhanced radiosensitivity of HeLa cell. Further experiments indicate that this mutant Artemis fragment bind to DNA-PKcs and ATM, inhibited phosphorylation of endogenous Artemis, the key molecule for DNA repair and cell radiosensitivity.
  
  
  CONCLUSIONS
  The dominant negative mutant Artemis fragment (D37N-413aa) enhanced tumor cell radiosensitivity through blocking activity of endogenous Artemis and DNA repair. It is the first time to modulate tumor cell radiosensitivity via targeting Artemis. This novel mechanism of radiosensitivity strongly suggests the potential role of Artemis in cancer therapy.
authors.affiliation: Cancer Institute, Zhejiang University School of Medicine, The Second Affiliated Hospital, Hangzhou, China.
authors.forename: Hai
authors.initials: H
authors.lastname: Liu
authors.forename: XiaoNan
authors.initials: X
authors.lastname: Sun
authors.forename: Shuo
authors.initials: S
authors.lastname: Zhang
authors.forename: WeiTing
authors.initials: W
authors.lastname: Ge
authors.forename: YongLiang
authors.initials: Y
authors.lastname: Zhu
authors.forename: JiaWei
authors.initials: J
authors.lastname: Zhang
authors.forename: Shu
authors.initials: S
authors.lastname: Zheng
mesh_terms: D018797:Cell Cycle Proteins / Q000235:genetics / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects*; D004260:DNA Repair / Q000187:drug effects / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000494:pharmacology; D004720:Endonucleases; D005260:Female; D006367:HeLa Cells / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D050506:Mutant Chimeric Proteins / Q000235:genetics / Q000494:pharmacology*; D009687:Nuclear Proteins / Q000235:genetics*; D010766:Phosphorylation; D011836:Radiation Tolerance / Q000187:drug effects* / Q000235:genetics; D012680:Sensitivity and Specificity; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000494:pharmacology
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D050506:Mutant Chimeric Proteins; D009687:Nuclear Proteins; D025521:Tumor Suppressor Proteins; C426344:DCLRE1C protein, human; D004720:Endonucleases