Caffeine sensitizes nondividing human fibroblasts to X rays by inducing a high frequency of misrepair

Tetsuya Kawata, Hisao Ito, Masayoshi Saito, Takashi Uno, Ryuichi Okayasu, Cuihua Liu, Momoe Kan'o, Kerry George, Francis A. Cucinotta

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Caffeine sensitizes cells to ionizing radiation, and this effect is believed to be associated with the disruption of DNA damage-responsive cell cycle checkpoints, which is controlled by ATM. Recent studies suggest that misrejoining of DSBs is one of the underlying mechanisms of AT cell hyper-radiosensitivity. In this study, we investigated the effects of caffeine and radiation on nongrowing G0 normal human fibroblast cells by determining cell survival and scoring aberrations in calyculin A-induced G 2 chromosomes. Results from the cell survival study indicate that after X-ray exposure G0 cells were sensitized by 24 h treatment with caffeine. Analysis of chromosome aberrations using FISH (fluorescence in situ hybridization) revealed a high frequency of aberrant cells and color junctions in the caffeine-treated cells. Since most DNA repair in nongrowing G0 cells is believed to result from nonhomologous end joining (NHEJ), caffeine may influence the fidelity of the NHEJ pathway in irradiated G0 cells.

Original languageEnglish
Pages (from-to)509-513
Number of pages5
JournalRadiation Research
Issue number4 II
Publication statusPublished - 2005 Oct

ASJC Scopus subject areas

  • Biophysics
  • Radiation
  • Radiology Nuclear Medicine and imaging


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