title: Suppressing RNA silencing with small molecules and the viral suppressor of RNA silencing protein p19.
abstract: RNA silencing is a gene regulatory and host defense mechanism whereby small RNA molecules are engaged by Argonaute (AGO) proteins, which facilitate gene knockdown of complementary mRNA targets. Small molecule inhibitors of AGO represent a convenient method for reversing this effect and have applications in human therapy and biotechnology. Viral suppressors of RNA silencing, such as p19, can also be used to suppress the pathway. Here we assess the compatibility of these two approaches, by examining whether synthetic inhibitors of AGO would inhibit p19-siRNA interactions. We observe that aurintricarboxylic acid (ATA) is a potent inhibitor of p19's ability to bind siRNA (IC50 = 0.43 μM), oxidopamine does not inhibit p19:siRNA interactions, and suramin is a mild inhibitor of p19:siRNA interactions (IC50 = 430 μM). We observe that p19 and suramin are compatible inhibitors of RNA silencing in human hepatoma cells. Our data suggests that at least some inhibitors of AGO may be used in combination with p19 to inhibit RNA silencing at different points in the pathway.
authors.affiliation: Department of Biochemistry, Microbiology and Immunology University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada; National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada.
authors.forename: Dana C
authors.initials: DC
authors.lastname: Danielson
authors.affiliation: Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada; National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada.
authors.forename: Roxana
authors.initials: R
authors.lastname: Filip
authors.affiliation: Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada; National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada.
authors.forename: Megan H
authors.initials: MH
authors.lastname: Powdrill
authors.affiliation: National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada.
authors.forename: Shifawn
authors.initials: S
authors.lastname: O'Hara
authors.affiliation: Department of Biochemistry, Microbiology and Immunology University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada; Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario, K1N 6N5, Canada; National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada. Electronic address: John.Pezacki@nrc-cnrc.gc.ca.
authors.forename: John P
authors.initials: JP
authors.lastname: Pezacki
mesh_terms: D060565:Argonaute Proteins / Q000235:genetics*; D045744:Cell Line, Tumor; D006801:Humans; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D013498:Suramin / Q000494:pharmacology
chemical_list: D060565:Argonaute Proteins; D034741:RNA, Small Interfering; D013498:Suramin
keywords: RNA silencing; Small interfering RNAs; Small molecule inhibitor; Viral suppressor of RNA silencing