A comprehensive strategy to discover inhibitors of the translesion synthesis DNA polymerase κ

PLoS One. 2012;7(10):e45032. doi: 10.1371/journal.pone.0045032. Epub 2012 Oct 8.


Human DNA polymerase kappa (pol κ) is a translesion synthesis (TLS) polymerase that catalyzes TLS past various minor groove lesions including N(2)-dG linked acrolein- and polycyclic aromatic hydrocarbon-derived adducts, as well as N(2)-dG DNA-DNA interstrand cross-links introduced by the chemotherapeutic agent mitomycin C. It also processes ultraviolet light-induced DNA lesions. Since pol κ TLS activity can reduce the cellular toxicity of chemotherapeutic agents and since gliomas overexpress pol κ, small molecule library screens targeting pol κ were conducted to initiate the first step in the development of new adjunct cancer therapeutics. A high-throughput, fluorescence-based DNA strand displacement assay was utilized to screen ∼16,000 bioactive compounds, and the 60 top hits were validated by primer extension assays using non-damaged DNAs. Candesartan cilexetil, manoalide, and MK-886 were selected as proof-of-principle compounds and further characterized for their specificity toward pol κ by primer extension assays using DNAs containing a site-specific acrolein-derived, ring-opened reduced form of γ-HOPdG. Furthermore, candesartan cilexetil could enhance ultraviolet light-induced cytotoxicity in xeroderma pigmentosum variant cells, suggesting its inhibitory effect against intracellular pol κ. In summary, this investigation represents the first high-throughput screening designed to identify inhibitors of pol κ, with the characterization of biochemical and biologically relevant endpoints as a consequence of pol κ inhibition. These approaches lay the foundation for the future discovery of compounds that can be applied to combination chemotherapy.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acrolein / metabolism
  • Benzimidazoles / pharmacology
  • Biphenyl Compounds / pharmacology
  • Cell Line, Transformed
  • Cell Survival / drug effects
  • Cell Survival / radiation effects
  • DNA / genetics
  • DNA / metabolism
  • DNA Adducts / genetics
  • DNA Adducts / metabolism
  • DNA Damage*
  • DNA Repair / drug effects*
  • DNA Repair / genetics
  • DNA-Directed DNA Polymerase / metabolism
  • Deoxyguanosine / analogs & derivatives
  • Deoxyguanosine / metabolism
  • Dose-Response Relationship, Drug
  • Drug Evaluation, Preclinical / methods
  • Enzyme Inhibitors / pharmacology*
  • Humans
  • Indoles / pharmacology
  • Nucleic Acid Synthesis Inhibitors*
  • Small Molecule Libraries
  • Terpenes / pharmacology
  • Tetrazoles / pharmacology
  • Ultraviolet Rays


  • Benzimidazoles
  • Biphenyl Compounds
  • DNA Adducts
  • Enzyme Inhibitors
  • Indoles
  • Nucleic Acid Synthesis Inhibitors
  • Small Molecule Libraries
  • Terpenes
  • Tetrazoles
  • alpha-hydroxypropanodeoxyguanosine
  • MK-886
  • Acrolein
  • DNA
  • manoalide
  • DNA-Directed DNA Polymerase
  • POLK protein, human
  • Deoxyguanosine
  • candesartan cilexetil