Caffeine inhibits the checkpoint kinase ATM

Curr Biol. 1999 Oct 7;9(19):1135-8. doi: 10.1016/s0960-9822(99)80486-2.


The basis of many anti-cancer therapies is the use of genotoxic agents that damage DNA and thus kill dividing cells. Agents that cause cells to override the DNA-damage checkpoint are predicted to sensitize cells to killing by genotoxic agents. They have therefore been sought as adjuncts in radiation therapy and chemotherapy. One such compound, caffeine, uncouples cell-cycle progression from the replication and repair of DNA [1] [2]. Caffeine therefore servers as a model compound in establishing the principle that agents that override DNA-damage checkpoints can be used to sensitize cells to the killing effects of genotoxic drugs [3]. But despite more than 20 years of use, the molecular mechanisms by which caffeine affects the cell cycle and checkpoint responses have not been identified. We investigated the effects of caffeine on the G2/M DNA-damage checkpoint in human cells. We report that the radiation-induced activation of the kinase Cds1 [4] (also known as Chk2 [5]) is inhibited by caffeine in vivo and that ATM kinase activity is directly inhibited by caffeine in vitro. Inhibition of ATM provides a molecular explanation of the attenuation of DNA-damage checkpoint responses and for the increased radiosensitivity of caffeine-treated cells [6] [7] [8].

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Androstadienes / pharmacology
  • Ataxia Telangiectasia Mutated Proteins
  • Caffeine / pharmacology*
  • Carrier Proteins*
  • Cell Cycle / drug effects*
  • Cell Cycle Proteins
  • Cell Line
  • Checkpoint Kinase 2
  • DNA Damage
  • DNA-Binding Proteins
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / pharmacology
  • HeLa Cells
  • Humans
  • Phosphoproteins / metabolism
  • Phosphorylation
  • Precipitin Tests
  • Protein Kinases / metabolism
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors*
  • Protein-Serine-Threonine Kinases / drug effects
  • Protein-Serine-Threonine Kinases / metabolism*
  • Time Factors
  • Tumor Suppressor Proteins
  • Wortmannin


  • Adaptor Proteins, Signal Transducing
  • Androstadienes
  • Carrier Proteins
  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • EIF4EBP1 protein, human
  • Enzyme Inhibitors
  • Phosphoproteins
  • Tumor Suppressor Proteins
  • Caffeine
  • Protein Kinases
  • Checkpoint Kinase 2
  • ATM protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • CHEK2 protein, human
  • Protein-Serine-Threonine Kinases
  • Wortmannin