title: A preliminary study on the radiation-resistance mechanism in ovarian cancer.
abstract: OBJECTIVE
  The present study was designed to explore the radiation-resistance mechanism by interfering in checkpoints kinase 1 (CHK1) and DNA-activated protein kinase (DNA-PK) genes with short hairpin RNA (shRNA) transfection into Skov3 cells derived from ovarian cancer and HeLa cells derived from cervical cancer.
  
  
  METHODS
  The cultured Skov3 and HeLa cells were transfected with plasmid vectors containing CHK1 shRNA and DNA-PK shRNA, respectively, through Lipofectimine™ 2000 mediation, and cultured for 20 hours before exposure to 2 Gy X-radiation. The cells were harvested 4 and 28 after X-irradiation respectively then washed 3 times with PBS. These cells were stained with Annexin V/PI and applied by flow cytometer to analyze alteration of apoptosis with software CellQuest.
  
  
  RESULTS
  The apoptotic response in Skov3 cells to X-radiation was significantly lower than that in HeLa cells at 4 hour (t = 15.22, P < 0.001) and 28 hours (t = 15.78, P < 0.001) of post-irradiation. The shRNA might not affect the apoptosis of Skov3 and HeLa cells, while shRNA-transfection significantly enhanced the apoptotic response in Skov3 cells to X-radiation as compared with that in HeLa cells.
  
  
  CONCLUSIONS
  The present work suggests that the CHK1 and DNA-PK genes are very likely to play a role in developing a radiation resistance in ovarian cancer.
authors.affiliation: Department of Radiotherapy, Second Teaching Hospital of Jilin University, Changchun, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Liao
authors.forename: Hong-mei
authors.initials: HM
authors.lastname: Zhang
authors.forename: Hai-hua
authors.initials: HH
authors.lastname: Li
authors.forename: Ren
authors.initials: R
authors.lastname: Zhou
authors.forename: Hui-ling
authors.initials: HL
authors.lastname: Mao
authors.forename: Yu-bing
authors.initials: YB
authors.lastname: Chen
authors.forename: Man-hua
authors.initials: MH
authors.lastname: Cui
mesh_terms: D017209:Apoptosis / Q000235:genetics / Q000528:radiation effects; D045744:Cell Line, Tumor; D000071877:Checkpoint Kinase 1; D051747:DNA-Activated Protein Kinase / Q000235:genetics / Q000378:metabolism; D005260:Female; D006367:HeLa Cells; D006801:Humans; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000532:radiotherapy; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D011827:Radiation; D011836:Radiation Tolerance / Q000235:genetics*; D014965:X-Rays
chemical_list: D011494:Protein Kinases; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1; D051747:DNA-Activated Protein Kinase