title: Inhibition of helicase activity by a small molecule impairs Werner syndrome helicase (WRN) function in the cellular response to DNA damage or replication stress.
abstract: Modulation of DNA repair proteins by small molecules has attracted great interest. An in vitro helicase activity screen was used to identify molecules that modulate DNA unwinding by Werner syndrome helicase (WRN), mutated in the premature aging disorder Werner syndrome. A small molecule from the National Cancer Institute Diversity Set designated NSC 19630 [1-(propoxymethyl)-maleimide] was identified that inhibited WRN helicase activity but did not affect other DNA helicases [Bloom syndrome (BLM), Fanconi anemia group J (FANCJ), RECQ1, RecQ, UvrD, or DnaB). Exposure of human cells to NSC 19630 dramatically impaired growth and proliferation, induced apoptosis in a WRN-dependent manner, and resulted in elevated γ-H2AX and proliferating cell nuclear antigen (PCNA) foci. NSC 19630 exposure led to delayed S-phase progression, consistent with the accumulation of stalled replication forks, and to DNA damage in a WRN-dependent manner. Exposure to NSC 19630 sensitized cancer cells to the G-quadruplex-binding compound telomestatin or a poly(ADP ribose) polymerase (PARP) inhibitor. Sublethal dosage of NSC 19630 and the chemotherapy drug topotecan acted synergistically to inhibit cell proliferation and induce DNA damage. The use of this WRN helicase inhibitor molecule may provide insight into the importance of WRN-mediated pathway(s) important for DNA repair and the replicational stress response.
authors.affiliation: Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health Biomedical Research Center, Baltimore, MD 21224, USA.
authors.forename: Monika
authors.initials: M
authors.lastname: Aggarwal
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Sommers
authors.forename: Robert H
authors.initials: RH
authors.lastname: Shoemaker
authors.forename: Robert M
authors.initials: RM
authors.lastname: Brosh
mesh_terms: D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects*; D004261:DNA Replication / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D005090:Exodeoxyribonucleases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006657:Histones / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D008301:Maleimides / Q000737:chemistry / Q000494:pharmacology*; D015394:Molecular Structure; D010080:Oxazoles / Q000494:pharmacology; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D053484:RecQ Helicases / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D016196:S Phase / Q000187:drug effects; D013312:Stress, Physiological / Q000187:drug effects; D013997:Time Factors; D059004:Topoisomerase I Inhibitors / Q000494:pharmacology; D019772:Topotecan / Q000494:pharmacology; D000071657:Werner Syndrome Helicase
chemical_list: C557741:1-(propoxymethyl)maleimide; D004791:Enzyme Inhibitors; C468783:H2AX protein, human; D006657:Histones; D008301:Maleimides; D010080:Oxazoles; D018809:Proliferating Cell Nuclear Antigen; D059004:Topoisomerase I Inhibitors; C431888:telomestatin; D019772:Topotecan; D005090:Exodeoxyribonucleases; D000251:Adenosine Triphosphatases; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase