Mitochondrial DNA influences radiation sensitivity and induction of apoptosis in human fibroblasts.
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.
Tang
J T
JT
Department of Radiation Oncology, Osaka University Medical School, Japan.
Yamazaki
H
H
Inoue
T
T
Koizumi
M
M
Yoshida
K
K
Ozeki
S
S
Inoue
T
T
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*
D004272:DNA, Mitochondrial