title: The effect of caffeine on post-replication repair and survival in two L5178Y cell lines with different sensitivities to UV irradiation.
abstract: 2 Strains of murine lymphoma L5178Y cells that varied from the point of view of sensitivity to UV irradiation (mean lethal doses: 3.6 and 8.5 J/m2 for L5178Y-R and L5178Y-S cells, respectively) also differed with respect to sensitization by caffeine. L5178Y-S cells were sensitized to UV irradiation by 0.75 mM caffeine, whereas in the same conditions L5178Y-R cells were not sensitized. Sedimentation analysis of the newly synthesized DNA indicated UV-induced gap formation in L5178Y-S cells only. The subsequent gap filling was inhibited by caffeine. Exposure to UV irradiation induced no gaps in L5178Y-R cells. However, when caffeine was added immediately after irradiation, DNA with reduced molecular weight was found in irradiated cells of both strains after a 2-h chase. On the other hand, caffeine inhibited elongation of undamaged DNA strands in neither of the 2 cell strains.
mesh_terms: D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D004247:DNA / Q000528:radiation effects; D004260:DNA Repair / Q000187:drug effects*; D007942:Leukemia, Experimental / Q000235:genetics*; D008223:Lymphoma / Q000235:genetics*; D010641:Phenotype; D011836:Radiation Tolerance; D014466:Ultraviolet Rays
chemical_list: D002110:Caffeine; D004247:DNA