The activity of the DNA-dependent protein kinase (DNA-PK) complex is determinant in the cellular response to nitrogen mustards

Biochimie. 2000 Jan;82(1):25-8. doi: 10.1016/s0300-9084(00)00341-2.


The DNA-dependent protein kinase plays a critical role in mammalian DNA double strand break (DSB) repair and in specialized recombination, such as lymphoid V(D)J recombination. Its regulatory subunit Ku (dimer of the Ku70 and Ku80 protein) binds to DNA and recruits the kinase catalytic sub-unit, DNA-PKcs. We show here that three different strains deficient in either the Ku80 (xrs-6) or DNA-PKcs (V-3, scid) component of DNA-PK are markedly sensitive (3.5- to 5-fold) to a group of DNA cross-linking agents, the nitrogen mustards (NMs) (melphalan and mechlorethamine) as compared to their parental cell line. Importantly, the level of hypersensitivity to these drugs was close to the level of hypersensitivity observed for radiomimetic agents that create DSBs in DNA (bleomycin and neocarzinostatin). In addition, sensitivity to NMs was restored to the parental level in the xrs-6 cell line stably transfected with the human Ku80 gene (xrs-6/Ku80), showing unequivocally that DNA-PK is involved in this phenotype. These results indicate that a function of the whole DNA-PK protein complex is involved in the cellular response to NMs and suggest that the repair of DNA interstrand cross-links induced in DNA by NMs involved a DNA-PK dependent pathway that shares common features with DNA DSBs repair.

MeSH terms

  • Animals
  • Antibiotics, Antineoplastic / pharmacology
  • Antigens, Nuclear*
  • Bleomycin / pharmacology
  • Cell Line / drug effects
  • Cell Survival / drug effects
  • Cross-Linking Reagents / pharmacology
  • DNA / drug effects
  • DNA Damage / drug effects
  • DNA Helicases*
  • DNA-Activated Protein Kinase
  • DNA-Binding Proteins / drug effects
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Humans
  • Ku Autoantigen
  • Mechlorethamine / pharmacology
  • Melphalan / pharmacology
  • Mice
  • Mice, SCID
  • Mutation
  • Nitrogen Mustard Compounds / pharmacology*
  • Nuclear Proteins / drug effects
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Protein-Serine-Threonine Kinases / drug effects*
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Transfection
  • Zinostatin / pharmacology


  • Antibiotics, Antineoplastic
  • Antigens, Nuclear
  • Cross-Linking Reagents
  • DNA-Binding Proteins
  • Nitrogen Mustard Compounds
  • Nuclear Proteins
  • Bleomycin
  • Mechlorethamine
  • DNA
  • Zinostatin
  • DNA-Activated Protein Kinase
  • PRKDC protein, human
  • Protein-Serine-Threonine Kinases
  • DNA Helicases
  • XRCC5 protein, human
  • Xrcc6 protein, human
  • Xrcc6 protein, mouse
  • Ku Autoantigen
  • Melphalan