Action of caffeine on x-irradiated HeLa cells. I. Delayed inhibition of DNA synthesis

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

DOI:https://doi.org/10.2307/3574633· OSTI ID:7276962

Tolmach, L J; Jones, R W; Busse, P M

Treatment of HeLa S3 cells with 1 mM caffeine delays progression through G1 by 1.5 hours but causes no other detectable inhibition of cell progression; it sometimes results in a large stimulation of thymidine incorporation. When this concentration is applied to cells that have been irradiated with 1-krad doses of 220-kV x rays, there is a marked suppression of both the inhibition of DNA synthesis and G2 arrest induced by the radiation. Larger doses require higher concentrations of caffeine to suppress the inhibition of DNA synthesis. Delaying addition until the rate of synthesis is at its minimum (1.5 hours after irradiation with 1 krad) results in a slightly accelerated recovery of the rate. Treatment before or during irradiation is without effect on the inhibition. Removal of the caffeine as late as 6 hours after its addition at the time of irradiation results in a prompt inhibition in DNA synthesis that mimics that observed immediately after irradiation in the absence of caffeine. These findings raise the possibility that the depression in rate of DNA systhesis might not result from radiation damage introduced into the replicon initiation system, but rather may be an indirect consequence of damage residing elsewhere in the irradiated cell.

• Research Organization: Washington Univ., St. Louis
• OSTI ID: 7276962
• Journal Information: Radiat. Res.; (United States), Vol. 71:3
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
CAFFEINE
RADIOSENSITIVITY EFFECTS
DNA
BIOSYNTHESIS
HELA CELLS
BIOLOGICAL RADIATION EFFECTS
CELL CYCLE
X RADIATION
BIOLOGICAL EFFECTS
DRUGS
ELECTROMAGNETIC RADIATION
HETEROCYCLIC COMPOUNDS
IONIZING RADIATIONS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PURINES
RADIATION EFFECTS
RADIATIONS
SYNTHESIS
XANTHINES
560121* - Radiation Effects on Cells- External Source- (-1987)