title: Mitochondrial DNA influences radiation sensitivity and induction of apoptosis in human fibroblasts.
abstract: BACKGROUND
  We aimed to assess the role of mitochondrial DNA (mtDNA) in ionizing irradiation.
  
  
  METHODS
  We examined three human fibroblast cell lines either lacking mtDNA (rho 0 cell), carrying mutant mtDNA (syn cell) or normal mtDNA (rho + cell). Cell survival curves were generated with colony formation and dye exclusion tests. Cell cycle analysis and apoptosis assay were performed by flow cytometry.
  
  
  RESULTS
  The rho 0 cell line showed a stronger resistance to irradiation than the other two cell lines when assessed by the colony formation assay. In the dye exclusion test, the rho 0 cells revealed a superior cell viability among the cell lines after 5 and 8 Gy irradiation. The rho 0 cells underwent apoptosis at lower rates than the other two cell lines after 2, 5 and 8 Gy irradiation, and showed no alterations in the cell cycle distribution among them.
  
  
  CONCLUSIONS
  mtDNA plays an important role in radiation sensitivity and induction of apoptosis.
authors.affiliation: Department of Radiation Oncology, Osaka University Medical School, Japan.
authors.forename: J T
authors.initials: JT
authors.lastname: Tang
authors.forename: H
authors.initials: H
authors.lastname: Yamazaki
authors.forename: T
authors.initials: T
authors.lastname: Inoue
authors.forename: M
authors.initials: M
authors.lastname: Koizumi
authors.forename: K
authors.initials: K
authors.lastname: Yoshida
authors.forename: S
authors.initials: S
authors.lastname: Ozeki
authors.forename: T
authors.initials: T
authors.lastname: Inoue
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D002453:Cell Cycle; D002460:Cell Line; D004272:DNA, Mitochondrial / Q000502:physiology*; D005434:Flow Cytometry; D006801:Humans; D011836:Radiation Tolerance / Q000502:physiology*
chemical_list: D004272:DNA, Mitochondrial