title: Silencing Prx1 and/or Prx5 sensitizes human esophageal cancer cells to ionizing radiation and increases apoptosis via intracellular ROS accumulation.
abstract: OBJECTIVE
  To investigate whether down-regulation of peroxiredoxin 1 (Prx1) and/or peroxiredoxin 5 (Prx5) sensitizes human esophageal cancer cells to ionizing radiation (IR).
  
  
  METHODS
  Human esophageal carcinoma cell lines Eca-109 and TE-1 were used. Prx mRNA expression profiles in Eca-109 and TE-1 cells were determined using RT-PCR. Two highly expressed isoforms of Prxs, Prx1 and Prx5, were silenced by RNA interference (RNAi). Following IR, intracellular reactive oxygen species (ROS) and apoptosis were measured using flow cytometry, the activities of catalase, superoxide dismutase and glutathione peroxidase were measured, and the radiosensitizing effect of RNAi was observed. Tumor xenograft model was also used to examine the radiosensitizing effect of RNAi in vivo.
  
  
  RESULTS
  Down-regulation of Prx1 and/or Prx5 by RNAi does not alter the activities of catalase, superoxide dismutase and glutathione peroxidase, but made human tumor cells more sensitive to IR-induced apoptosis both in vitro and in vivo. When the two isoforms were decreased simultaneously, intracellular ROS and apoptosis significantly increased after IR.
  
  
  CONCLUSIONS
  Silencing Prx1 and/or Prx5 by RNAi sensitizes human Eca-109 and TE-1 cells to IR, and the intracellular ROS accumulation may contribute to the radiosensitizing effect of the RNAi.
authors.affiliation: Department of Gastroenterology, the Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Mai-cang
authors.initials: MC
authors.lastname: Gao
authors.forename: Xiao-di
authors.initials: XD
authors.lastname: Jia
authors.forename: Qi-fei
authors.initials: QF
authors.lastname: Wu
authors.forename: Yan
authors.initials: Y
authors.lastname: Cheng
authors.forename: Fen-rong
authors.initials: FR
authors.lastname: Chen
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D004938:Esophageal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D020868:Gene Silencing; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011839:Radiation, Ionizing; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D018398:Homeodomain Proteins; C082157:PRRX1 protein, human; D017382:Reactive Oxygen Species