title: Fenofibrate decreases radiation sensitivity via peroxisome proliferator-activated receptor α-mediated superoxide dismutase induction in HeLa cells.
abstract: OBJECTIVE
  The fibrates are ligands for peroxisome proliferator-activated receptor (PPAR) α and used clinically as hypolipidemic drugs. The fibrates are known to cause peroxisome proliferation, enhance superoxide dismutase (SOD) expression and catalase activity. The antioxidant actions of the fibrates may modify radiation sensitivity. Here, we investigated the change of the radiation sensitivity in two cervix cancer cell lines in combination with fenofibrate (FF).
  
  
  METHODS
  Activity and protein expression of SOD were measured according to the concentration of FF. The mRNA expressions were measured by using real time reverse-transcription polymerase chain reaction. Combined cytotoxic effect of FF and radiation was measured by using clonogenic assay.
  
  
  RESULTS
  In HeLa cells total SOD activity was increased with increasing FF doses up to 30 µM. In the other hand, the catalase activity was increased a little. As with activity the protein expression of SOD1 and SOD2 was increased with increasing doses of FF. The mRNAs of SOD1, SOD2, PPARα and PPARγ were increased with increasing doses of FF. The reactive oxygen species (ROS) produced by radiation was decreased by preincubation with FF. The surviving fractions (SF) by combining FF and radiation was higher than those of radiation alone. In Me180 cells SOD and catalase activity were not increased with FF. Also, the mRNAs of SOD1, SOD2, and PPARα were not increased with FF. However, the mRNA of PPARγ was increased with FF.
  
  
  CONCLUSIONS
  FF can reduce radiation sensitivity by ROS scavenging via SOD induction in HeLa. SOD induction by FF is related with PPARα.
authors.affiliation: Department of Radiation Oncology, Chungbuk National University College of Medicine, Cheongju, Korea.
authors.forename: Xianguang
authors.initials: X
authors.lastname: Liu
authors.forename: Seong Soon
authors.initials: SS
authors.lastname: Jang
authors.forename: Zhengzhe
authors.initials: Z
authors.lastname: An
authors.forename: Hyejin
authors.initials: H
authors.lastname: Song
authors.forename: Won-Dong
authors.initials: WD
authors.lastname: Kim
authors.forename: Jae-Ran
authors.initials: JR
authors.lastname: Yu
authors.forename: Woo-Yoon
authors.initials: WY
authors.lastname: Park