Repair of chromosome damage induced by X-irradiation during G2 phase in a line of normal human fibroblasts and its malignant derivative

Journal Article · Sun Aug 01 04:00:00 EDT 1982 · J. Natl. Cancer Inst.; (United States)

OSTI ID:6654578

Parshad, R; Gantt, R; Sanford, K K; Jones, G M; Tarone, R E

A line of normal human skin fibroblasts (KD) differed from its malignant derivative (HUT-14) in the extent of cytogenetic damage induced by X-irradiation during G2 phase. Malignant cells had significantly more chromatid breaks and gaps after exposure to 25, 50, or 100 rad. The gaps may represent single-strand breaks. Results from alkaline elution of cellular DNA immediately after irradiation showed that the normal and malignant cells in asynchronous population were equally sensitive to DNA single-strand breakage by X-irradiation. Caffeine or beta-cytosine arabinoside (ara-C), inhibitors of DNA repair, when added directly following G2 phase exposure, significantly increased the incidence of radiation-induced chromatid damage in the normal cells. In contrast, similar treatment of the malignant cells had little influence. Ara-C differed from caffeine in its effects; whereas both agents increased the frequency of chromatid breaks and gaps, only ara-C increased the frequency of gaps to the level observed in the irradiated malignant cells. Addition of catalase, a scavenger of the derivative free hydroxyl radical (.OH), to the cultures of malignant cells before, during, and following irradiation significantly reduced the chromatid damage; and catalase prevented formation of chromatid gaps. The DNA damage induced by X-ray during G2 phase in the normal KD cells was apparently repaired by a caffeine- and ara-C-sensitive mechanism(s) that was deficient or absent in their malignant derivatives.

• Research Organization: Department of Pathology, Howard University College of Medicine, Washington, DC
• OSTI ID: 6654578
• Journal Information: J. Natl. Cancer Inst.; (United States), Journal Name: J. Natl. Cancer Inst.; (United States) Vol. 69:2; ISSN JNCIA
• Country of Publication: United States
• Language: English

Related Subjects

550603 -- Medicine-- External Radiation in Therapy-- (1980-)
560121* -- Radiation Effects on Cells-- External Source-- (-1987)
62 RADIOLOGY AND NUCLEAR MEDICINE
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CELL CYCLE
CHROMOSOMAL ABERRATIONS
CHROMOSOMES
CONNECTIVE TISSUE CELLS
DNA
DOSES
ELECTROMAGNETIC RADIATION
FIBROBLASTS
IONIZING RADIATIONS
MUTATIONS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
RADIATION DOSES
RADIATION EFFECTS
RADIATIONS
RADIOSENSITIVITY
RADIOSENSITIVITY EFFECTS
RECOVERY
REPAIR
RESPONSE MODIFYING FACTORS
SOMATIC CELLS
X RADIATION