DNA double-strand breaks measured in individual cells subjected to gel electrophoresis

Journal Article · Sun Sep 01 00:00:00 EDT 1991 · Cancer Research; (United States)

OSTI ID:5263193

Olive, P L; Wlodek, D; Banath, J P ^[1]

---

1. British Columbia Cancer Research Centre, Vancouver (Canada)

Microscopic examination of individual mammalian cells embedded in agarose, subjected to electrophoresis, and stained with a fluorescent DNA-binding dye provides a novel way of measuring DNA damage and more importantly, of assessing heterogeneity in DNA damage within a mixed population of cells. With this method, DNA double-strand breaks can be detected in populations of cells exposed to X-ray doses as low as 5 Gy. The radiation dose-response relationship for initial formation of double-strand breaks was identical for cell lines irradiated in G1, regardless of their sensitivity to killing by ionizing radiation. However, for cells irradiated in S phase, DNA migration was significantly reduced. For Chinese hamster V79 cells, Chinese hamster ovary cells, WiDr human colon carcinoma cells, and L5178Y-R mouse lymphoblastoid cells, S-phase DNA appeared to be about 3 times less sensitive to X-ray damage than DNA from other phases of the cell cycle. However, for the very radiosensitive L5178Y-S cells, the migration of replicating DNA was reduced only slightly. For Chinese hamster V79 and Chinese hamster ovary cells, damage was repaired at a similar rate in all cells of the population, and 85% of the breaks were rejoined within 2 h after irradiation. The radiosensitive L5178Y-S cells repaired damage more slowly than V79 or Chinese hamster ovary cells; 2 h after exposure to 50 Gy, approximately 50% of the damage was still present.

• OSTI ID: 5263193
• Journal Information: Cancer Research; (United States), Vol. 51:17; ISSN 0008-5472
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
GENETIC RADIATION EFFECTS
STRAND BREAKS
RADIOINDUCTION
TUMOR CELLS
CARCINOMAS
CHO CELLS
DNA REPAIR
DOSE-RESPONSE RELATIONSHIPS
ELECTROPHORESIS
HAMSTERS
LARGE INTESTINE
MAN
MICE
RADIATION DOSES
X RADIATION
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
BODY
DIGESTIVE SYSTEM
DISEASES
DOSES
ELECTROMAGNETIC RADIATION
GASTROINTESTINAL TRACT
GENETIC EFFECTS
INTESTINES
IONIZING RADIATIONS
MAMMALS
NEOPLASMS
ORGANS
PRIMATES
RADIATION EFFECTS
RADIATIONS
RECOVERY
REPAIR
RODENTS
VERTEBRATES
560120* - Radiation Effects on Biochemicals
Cells
& Tissue Culture