title: Chronic low-dose radiation inhibits the cells death by cytotoxic high-dose radiation increasing the level of AKT and acinus proteins via NF-κB activation.
abstract: OBJECTIVE
  This study explored the effects of low-dose and low-dose-rate irradiation in human lung fibroblast CCD-18Lu cells and examined the role of AKT (protein kinase B, PKB) in cellular responses.
  
  
  METHODS
  We examined cell survival after chronic low-dose irradiation (0.01 Gy or 0.05 Gy) with challenging high-dose (2 or 10 Gy) irradiation. We examined the effect of AKT activation on cell survival after chronic low-dose radiation using transduced cells with retroviral vector expressing constitutively active AKT (CA-AKT).
  
  
  RESULTS
  Chronic low-dose priming irradiation increased cells viability against the challenging high-dose irradiation. Irradiation at 0.05 Gy increased cellular levels of AKT and acinus long form (L) and short form (S). The chronic low-dose radiation promoted cells proliferation in the exogenously expressed CA-AKT cells. It also increased nuclear factor-kappa B (NF-κB) activity in a biphasic induction pattern. Suppression of NF-κB activation by mutant form of inhibitor of kappa B alpha (IκBαM) antagonized the radiation-induced expression of AKT and acinus L and S.
  
  
  CONCLUSIONS
  Chronic low-dose radiation increases the levels of AKT and acinus proteins via NF-κB activation, and the NF-κB/AKT pathway responding to chronic low-dose irradiation plays an important role in the radiation adaptive response.
authors.affiliation: Radiation Health Research Institute, Korea Hydro & Nuclear Power Co., Ltd, Seoul, Korea.
authors.forename: Hyung Sun
authors.initials: HS
authors.lastname: Park
authors.forename: Ki Moon
authors.initials: KM
authors.lastname: Seong
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Cha Soon
authors.initials: CS
authors.lastname: Kim
authors.forename: Kwang Hee
authors.initials: KH
authors.lastname: Yang
authors.forename: Young-Woo
authors.initials: YW
authors.lastname: Jin
authors.forename: Seon Young
authors.initials: SY
authors.lastname: Nam
mesh_terms: D016923:Cell Death / Q000528:radiation effects; D002460:Cell Line; D049109:Cell Proliferation / Q000528:radiation effects; D002470:Cell Survival / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D016328:NF-kappa B / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D013997:Time Factors
chemical_list: C121310:ACIN1 protein, human; D016328:NF-kappa B; D009687:Nuclear Proteins; D051057:Proto-Oncogene Proteins c-akt