title: Peroxiredoxin IV protects cells from radiation-induced apoptosis in head-and-neck squamous cell carcinoma.
abstract: OBJECTIVE
  Human peroxiredoxins (Prxs) are known as a family of thiol-specific antioxidant enzymes, among which Prx-I and -II play an important role in protecting cells from irradiation-induced cell death. It is not known whether Prx-IV also protects cells from ionizing radiation (IR).
  
  
  METHODS
  To evaluate the protective role of Prx-IV in IR, we transfected full-length Prx-IV cDNA into AMC-HN3 cells, which weakly express endogenous Prx-IV, and knocked down the expression of Prx-IV with siRNA methods using AMC-HN7 cells, which express high levels of endogenous Prx-IV. Radiosensitivity profiles in these cells were evaluated using clonogenic assay, FACS analysis, cell viability, and TUNEL assay.
  
  
  RESULTS
  Three Prx-IV expressing clones were isolated. Prx-IV regulated intracellular reactive oxygen species (ROS) levels and made cells more resistant to IR-induced apoptosis. Furthermore, the knockdown of Prx-IV with siRNA made cells more sensitive to IR-induced apoptosis.
  
  
  CONCLUSIONS
  The results of these studies suggest that Prx-IV may play an important role in protecting cells from IR-induced apoptosis in head-and-neck squamous cell carcinoma.
authors.affiliation: Department of Otolaryngology, Institute of Health Sciences, College of Medicine, Gyeongsang National University, Jinju, South Korea.
authors.forename: Jung Je
authors.initials: JJ
authors.lastname: Park
authors.forename: Hyo Won
authors.initials: HW
authors.lastname: Chang
authors.forename: Eun-Jeong
authors.initials: EJ
authors.lastname: Jeong
authors.forename: Jong-Lyel
authors.initials: JL
authors.lastname: Roh
authors.forename: Seung-Ho
authors.initials: SH
authors.lastname: Choi
authors.forename: Sea-Yuong
authors.initials: SY
authors.lastname: Jeon
authors.forename: Gyung Hyuck
authors.initials: GH
authors.lastname: Ko
authors.forename: Sang Yoon
authors.initials: SY
authors.lastname: Kim
mesh_terms: D017209:Apoptosis / Q000502:physiology* / Q000528:radiation effects; D002294:Carcinoma, Squamous Cell / Q000503:physiopathology / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D055785:Gene Knockdown Techniques; D006258:Head and Neck Neoplasms / Q000503:physiopathology / Q000532:radiotherapy*; D006801:Humans; D054464:Peroxiredoxins / Q000235:genetics / Q000502:physiology*; D011836:Radiation Tolerance / Q000235:genetics / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000032:analysis; D014162:Transfection / Q000379:methods
chemical_list: D017382:Reactive Oxygen Species; D054464:Peroxiredoxins