title: [Observation of radiobiological characteristics in a HepG2 cell line with mitochondrial DNA deletion].
abstract: OBJECTIVE
  To study the radiobiological characteristics of a HepG2 cell line with mitochondrial DNA (mtDNA) deletion.
  
  
  METHODS
  HepG2 cells were cultured in a medium containing ethidium bromide, acetylformic acid and uracil. The HepG2 cell line with mtDNA deletion (ρ(0)HepG2 cells) were acquired after 30 subcultures by limited dilution cloning. The cell survival was then observed in the absence of acetylformic acid and uracil, and the total mtDNA deletion in the cells was confirmed by PCR. The radiosensitivity of HepG2 and ρ(0)HepG2 cells was evaluated by exposure to gradient doses of 6 MV X ray irradiation. The cell apoptosis was assessed following a 2 Gy X-ray exposure with Hochest33342 staining, and the invasiveness of ρ(0)HepG2 cells was measured by Transwell assay.
  
  
  RESULTS
  HepG2 cells could survive 30 subcultures in the presence of ethidium bromide, and massive cell death occurred after removal of acetylformic acid and uracil from the medium. PCR confirmed total mtDNA deletion from ρ(0)HepG2 cells, whose α/β value was significantly lower than that of HepG2 cells. ρ(0)Hep-G2 cells showed an obviously lowered cell apoptosis rate following X-ray exposure with enhanced cell invasiveness.
  
  
  CONCLUSIONS
  HepG2 cells can be induced by ethidium bromide into ρ(0)HepG2 cells with an increased radiation resistance, anti-apoptosis ability and cell invasiveness.
authors.affiliation: Department of Radiology, Cancer Center, Guangdong General Hospital/Guangdong Academy of Medical Science, Guangzhou 510080, China. E-mail: sunrise761114@foxmail.com.
authors.forename: Hengwen
authors.initials: H
authors.lastname: Sun
authors.forename: Yi
authors.initials: Y
authors.lastname: Pan
authors.forename: Zijun
authors.initials: Z
authors.lastname: Zeng
authors.forename: Liangyi
authors.initials: L
authors.lastname: Fang
authors.forename: Hongdan
authors.initials: H
authors.lastname: Zhang
authors.forename: Songxi
authors.initials: S
authors.lastname: Xie
authors.forename: Weixiong
authors.initials: W
authors.lastname: Li
authors.forename: Jiabin
authors.initials: J
authors.lastname: Xu
mesh_terms: D017209:Apoptosis; D003470:Culture Media / Q000737:chemistry; D004272:DNA, Mitochondrial / Q000235:genetics*; D004996:Ethidium / Q000737:chemistry; D056945:Hep G2 Cells / Q000528:radiation effects*; D006801:Humans; D011836:Radiation Tolerance / Q000235:genetics*; D017384:Sequence Deletion; D014965:X-Rays
chemical_list: D003470:Culture Media; D004272:DNA, Mitochondrial; D004996:Ethidium