Biochemical evidence for deficient DNA repair leading to enhanced G2 chromatid radiosensitivity and susceptibility to cancer

Journal Article · Sat Nov 01 04:00:00 EST 1986 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3576817· OSTI ID:6928395

Gantt, R; Parshad, R; Price, F M; Sanford, K K

Human tumor cells and cells from cancer-prone individuals, compared with those from normal individuals, show a significantly higher incidence of chromatid breaks and gaps seen in metaphase cells immediately after G2 X irradiation. Previous studies with DNA repair-deficient mutants and DNA repair inhibitors strongly indicate that the enhancement results from a G2 deficiency(ies) in DNA repair. We report here biochemical evidence for a DNA repair deficiency that correlates with the cytogenetic studies. In the alkaline elution technique, after a pulse label with radioactive thymidine in the presence of 3-acetylaminobenzamide (a G2-phase blocker) and X irradiation, DNA from tumor or cancer-prone cells elutes more rapidly during the postirradiation period than that from normal cells. These results indicate that the DNA of tumor and cancer-prone cells either repairs more slowly or acquires more breaks than that of normal cells; breaks can accumulate during incomplete or deficient repair processes. The kinetic difference between normal and tumor or cancer-prone cells in DNA strand-break repair reaches a maximum within 2 h, and this maximum corresponds to the kinetic difference in chromatid aberration incidence following X irradiation reported previously. These findings support the concept that cells showing enhanced G2 chromatid radiosensitivity are deficient in DNA repair. The findings could also lead to a biochemical assay for cancer susceptibility.

• Research Organization: National Cancer Institute, Bethesda, MD
• OSTI ID: 6928395
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 2; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560120* -- Radiation Effects on Biochemicals
Cells
& Tissue Culture
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMAL CELLS
BIOLOGICAL RECOVERY
BIOLOGICAL REPAIR
CHROMATIDS
DISEASES
DNA REPAIR
ELECTROMAGNETIC RADIATION
IN VITRO
IONIZING RADIATIONS
NEOPLASMS
RADIATIONS
RADIOSENSITIVITY
RECOVERY
REPAIR
TUMOR CELLS
X RADIATION