title: Altered growth and radiosensitivity in neural precursor cells subjected to oxidative stress.
abstract: OBJECTIVE
  To determine whether changes in oxidative stress could enhance the sensitivity of neural precursor cells to ionizing radiation.
  
  
  METHODS
  Two strategies were used whereby oxidative stress was modulated endogenously, through manipulation cell culture density, or exogenously, through direct addition of hydrogen peroxide.
  
  
  RESULTS
  Cells subjected to increased endogenous oxidative stress through low-density growth routinely exhibited an inhibition of growth following irradiation. However, cells subjected to chronic exogenous oxidative treatments showed increased sensitivity to proton and gamma-irradiation compared to untreated controls. Reduced survival of irradiated cultures subjected to oxidizing conditions was corroborated using enzymatic viability assays, and was observed over a range of doses (1 - 5 Gy) and post-irradiation re-seeding densities (20 - 200 K/plate).
  
  
  CONCLUSIONS
  Collectively our results provide further support for the importance of redox state in the regulation of neural precursor cell function, and suggest that oxidative stress can inhibit the proliferative potential of cells through different mechanisms. This is likely to compromise survival and under conditions where excess exogenous oxidants might predominate, sensitivity to irradiation may be enhanced.
authors.affiliation: Department of Radiation Oncology, University of California, Medical Sciences I, Irvine, California 92697-2695, USA. climoli@uci.edu
authors.forename: Charles L
authors.initials: CL
authors.lastname: Limoli
authors.forename: Erich
authors.initials: E
authors.lastname: Giedzinski
authors.forename: Jennifer
authors.initials: J
authors.lastname: Baure
authors.forename: Radoslaw
authors.initials: R
authors.lastname: Rola
authors.forename: John R
authors.initials: JR
authors.lastname: Fike
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology / Q000528:radiation effects; D000818:Animals; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004307:Dose-Response Relationship, Radiation; D039902:Multipotent Stem Cells / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects*; D009474:Neurons / Q000166:cytology / Q000502:physiology* / Q000528:radiation effects*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D011829:Radiation Dosage; D011836:Radiation Tolerance / Q000502:physiology; D051381:Rats