Action of caffeine on x-irradiated HeLa cells. II. Synergistic lethality

Journal Article · Thu Sep 01 04:00:00 EDT 1977 · Radiat. Res.; (United States)

DOI:https://doi.org/10.2307/3574634· OSTI ID:7208166

Busse, P M; Bose, S K; Jones, R W; Tolmach, L J

Postirradiation treatment of HeLa S3 cells with 1 mM caffeine results in a marked diminution of the surviving fraction as scored by colony formation. The decrease is dose dependent; the effect of a 24-hour postirradiation treatment of a nonsynchronous population with caffeine is to change the terminal slope of the survival curve and its intercept. D/sub 0/ is reduced from 130 to 60 rad; the extrapolation number is increased about twofold. The amount of postirradiation killing is maximal if cells are exposed to caffeine at a concentration of at least 1 mM for 8 hours; less than 10% of unirradiated cells are killed under these conditions. Dose-response curves were also obtained for synchronous cells at various phases of the cell cycle. Similar results were obtained at all cell ages, but the magnitude of the effect is age dependent. This age dependence was further explored in experiments in which mitotically collected cells were exposed to 300 or 500 rad doses at 2-hour intervals throughout the cell cycle. Treatment with caffeine for 24 hours after irradiation enchances the killing of cells late in the cycle more than cells in G1. The sensitivities of two other cell lines, CHO and EMT6, also were examined; both are substantially less sensitive to caffeine. The smaller cell-cycle dependence of CHO cells is qualitatively the same as that of HeLa cells.

• Research Organization: Washington Univ., St. Louis
• OSTI ID: 7208166
• Journal Information: Radiat. Res.; (United States), Journal Name: Radiat. Res.; (United States) Vol. 71:3; ISSN RAREA
• Country of Publication: United States
• Language: English

Related Subjects

560121* -- Radiation Effects on Cells-- External Source-- (-1987)
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AGE DEPENDENCE
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CAFFEINE
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ELECTROMAGNETIC RADIATION
HELA CELLS
HETEROCYCLIC COMPOUNDS
IONIZING RADIATIONS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PURINES
RADIATION EFFECTS
RADIATIONS
RADIOSENSITIVITY EFFECTS
SURVIVAL CURVES
SYNERGISM
X RADIATION
XANTHINES