The effect of caffeine on X-ray-induced mitotic delay in normal human and ataxia-telangiectasia fibroblasts.
We previously showed that radiation-sensitive fibroblasts from ataxia-telangiectasia (A-T) patients sustain less G2 delay after X-irradiation than normal fibroblasts (Scott and Zampetti-Bosseler, 1982). Caffeine is known to reduce the amount of X-ray-induced delay in various mammalian cell types. Painter and Young (1980) proposed that A-T cells have an altered chromatin structure, similar to that of caffeine-treated normal cells and that this results in a failure of A-T cells to delay their progression through the cell cycle to allow time for DNA repair. We now show that caffeine treatment after X-irradiation reduces G2 delay in both A-T and normal cells. We confirm the results previously obtained on lymphocytes that caffeine potentiates the chromosome-damaging effects of X-rays in both A-T and normal fibroblasts. These and other data suggest that the radiation responses of A-T cells and of caffeine-treated normal cells are caused by different mechanisms.
D001260:Ataxia Telangiectasia / Q000378:metabolism / Q000473:pathology*; D002110:Caffeine / Q000494:pharmacology*; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D004260:DNA Repair; D005347:Fibroblasts / Q000187:drug effects; D006801:Humans; D007399:Interphase / Q000187:drug effects / Q000528:radiation effects; D008938:Mitosis / Q000187:drug effects* / Q000528:radiation effects; D013997:Time Factors
D002110:Caffeine