title: Activation of the nuclear factor κB pathway by heavy ion beams of different linear energy transfer.
abstract: OBJECTIVE
  Risk assessment of radiation exposure during long-term space missions requires the knowledge of the relative biological effectiveness (RBE) of space radiation components. Few data on gene transcription activation by different heavy ions are available, suggesting a dependence on linear energy transfer. The transcription factor Nuclear Factor κB (NF-κB) can be involved in cancerogenesis. Therefore, NF-κB activation by accelerated heavy ions of different linear energy transfer (LET) was correlated to survival.
  
  
  METHODS
  NF-κB-dependent gene induction after exposure to heavy ions was detected in stably transfected human embryonic kidney 293 cells (HEK-pNF-κB-d2EGFP/Neo cells carrying a neomycin resistance), using the destabilized Enhanced Green Fluorescent Protein (d2EGFP) as reporter.
  
  
  RESULTS
  Argon (LET 272 keV/μm) and neon ions (LET 91 keV/μm) had the highest potential to activate NF-κB, resulting in a RBE of 8.9 in comparison to 150 kV X-rays. The RBE for survival also reached its maximum in this LET range, with a maximal value of 2.
  
  
  CONCLUSIONS
  NF-κB might be involved in modulating survival responses of cells hit by heavy ions in the LET range of 91-272 keV/μm and could therefore become a factor to be considered for risk assessment of radiation exposure during space travel.
authors: German Aerospace Centre, DLR, Institute of Aerospace Medicine, Radiation Biology, Linder Höhe, Köln, Germany. christine.hellweg@dlr.de
authors: Christine E
authors: CE
authors: Hellweg
authors: Christa
authors: C
authors: Baumstark-Khan
authors: Claudia
authors: C
authors: Schmitz
authors: Patrick
authors: P
authors: Lau
authors: Matthias M
authors: MM
authors: Meier
authors: Isabelle
authors: I
authors: Testard
authors: Thomas
authors: T
authors: Berger
authors: Günther
authors: G
authors: Reitz
mesh_terms: D000054:Acceleration; D002470:Cell Survival / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D049452:Green Fluorescent Proteins / Q000235:genetics; D057809:HEK293 Cells; D020450:Heavy Ions / Q000009:adverse effects*; D006801:Humans; D018499:Linear Energy Transfer; D016328:NF-kappa B / Q000378:metabolism*; D012062:Relative Biological Effectiveness; D015398:Signal Transduction / Q000528:radiation effects*; D013026:Space Flight; D014965:X-Rays / Q000009:adverse effects
chemical_list: D016328:NF-kappa B; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins