title: Caffeine post-treatment causes a shift in the chromosome aberration types induced by mitomycin C, suggesting a caffeine-sensitive mechanism of DNA repair in G2.
abstract: Human lymphocytes were exposed in G1 to mitomycin C (2.5 microM for 2 h) and harvested at 3-h intervals from 48 to 84 h after stimulation. All cultures were also post-treated in G2 with caffeine (2 mM). Different types of chromosomal aberrations were scored in the first division metaphases. Caffeine increases all chromosome aberration types by promoting a premature mitosis of damaged cells. However, when the frequency of damaged cells is not affected by the caffeine post-treatment, a reduction of the frequency of the exchange-type aberrations was shown. The possibility that caffeine interferes with some mechanism of G2 repair is discussed.
mesh_terms: D002110:Caffeine / Q000633:toxicity*; D002478:Cells, Cultured; D002869:Chromosome Aberrations; D004260:DNA Repair / Q000187:drug effects*; D006801:Humans; D007399:Interphase / Q000187:drug effects; D008214:Lymphocytes / Q000187:drug effects; D016685:Mitomycin; D008937:Mitomycins / Q000633:toxicity*
chemical_list: D008937:Mitomycins; D002110:Caffeine; D016685:Mitomycin