title: Selenium influences the radiation sensitivity of C6 rat glioma cells.
abstract: BACKGROUND
  A radioprotective effect of low selenium doses on normal tissue and a possible radiosensitization of tumor cells at higher concentrations have been previously suggested. However, systematic experimental and clinical data are scarce.
  
  
  METHODS
  C6 cells were cultured for 14 days at different selenite concentrations (0 microM, 2 microM, 3 microM and 3.6 microM) and irradiated with 0 Gy to 20 Gy. Plating efficiency and survival were determined using the colony assay.
  
  
  RESULTS
  The overall radiosensitivity was low (D0,control=6.1 Gy). Irradiated cells exposed to increasing selenite concentrations showed a lower plating efficiency and, for doses > 2 Gy, a lower survival than the control. For Se concentrations of 0 microM, 2 microM and 3 microM, respectively, SF2 amounted to 0.72, 0.48 and 0.46, and SF5 to 0.37, 0.25 and 0.12. Student's t-test yielded a significant difference between the 0 microM and 3 microM curves at 5 Gy (p=0.02) and 10 Gy (p=0.009).
  
  
  CONCLUSIONS
  Our experiments suggest a radiosensitizing effect of selenite in glioma cells at concentrations of 2-3 microM.
authors.affiliation: Department of Radiotherapy and Radiation Oncology, University Hospital of Muenster, Germany. pschuel@uni-muenster.de
authors.forename: Patrick
authors.initials: P
authors.lastname: Schueller
authors.forename: Sylvia
authors.initials: S
authors.lastname: Puettmann
authors.forename: Oliver
authors.initials: O
authors.lastname: Micke
authors.forename: Volker
authors.initials: V
authors.lastname: Senner
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schaefer
authors.forename: Normann
authors.initials: N
authors.lastname: Willich
mesh_terms: D000818:Animals; D002455:Cell Division / Q000187:drug effects / Q000528:radiation effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D005910:Glioma / Q000473:pathology / Q000532:radiotherapy*; D011836:Radiation Tolerance / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology* / Q000633:toxicity; D051381:Rats; D018038:Sodium Selenite / Q000494:pharmacology* / Q000633:toxicity
chemical_list: D011838:Radiation-Sensitizing Agents; D018038:Sodium Selenite