A high-throughput screen to identify novel small molecule inhibitors of the Werner Syndrome Helicase-Nuclease (WRN)

PLoS One. 2019 Jan 9;14(1):e0210525. doi: 10.1371/journal.pone.0210525. eCollection 2019.

Abstract

Werner syndrome (WS), an autosomal recessive genetic disorder, displays accelerated clinical symptoms of aging leading to a mean lifespan less than 50 years. The WS helicase-nuclease (WRN) is involved in many important pathways including DNA replication, recombination and repair. Replicating cells are dependent on helicase activity, leading to the pursuit of human helicases as potential therapeutic targets for cancer treatment. Small molecule inhibitors of DNA helicases can be used to induce synthetic lethality, which attempts to target helicase-dependent compensatory DNA repair pathways in tumor cells that are already genetically deficient in a specific pathway of DNA repair. Alternatively, helicase inhibitors may be useful as tools to study the specialized roles of helicases in replication and DNA repair. In this study, approximately 350,000 small molecules were screened based on their ability to inhibit duplex DNA unwinding by a catalytically active WRN helicase domain fragment in a high-throughput fluorometric assay to discover new non-covalent small molecule inhibitors of the WRN helicase. Select compounds were screened to exclude ones that inhibited DNA unwinding by other helicases in the screen, bound non-specifically to DNA, acted as irreversible inhibitors, or possessed unfavorable chemical properties. Several compounds were tested for their ability to impair proliferation of cultured tumor cells. We observed that two of the newly identified WRN helicase inhibitors inhibited proliferation of cancer cells in a lineage-dependent manner. These studies represent the first high-throughput screen for WRN helicase inhibitors and the results have implications for anti-cancer strategies targeting WRN in different cancer cells and genetic backgrounds.

Publication types

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

MeSH terms

  • Biocatalysis
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • DNA / metabolism
  • Enzyme Assays
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Fluorometry
  • High-Throughput Screening Assays / methods*
  • Humans
  • Inhibitory Concentration 50
  • Reproducibility of Results
  • Small Molecule Libraries / analysis*
  • Small Molecule Libraries / chemistry
  • Small Molecule Libraries / pharmacology*
  • Werner Syndrome Helicase / antagonists & inhibitors*
  • Werner Syndrome Helicase / metabolism

Substances

  • Enzyme Inhibitors
  • Small Molecule Libraries
  • DNA
  • Werner Syndrome Helicase

Grants and funding

This work was supported entirely by the Intramural Research Programs of the National Center for Advancing Translational Sciences (NCATS), National Institutes of Health (NIH) and the National Institute on Aging, NIH.