title: Guanabenz (Wytensin™) selectively enhances uptake and efficacy of hydrophobically modified siRNAs.
abstract: One of the major obstacles to the pharmaceutical success of oligonucleotide therapeutics (ONTs) is efficient delivery from the point of injection to the intracellular setting where functional gene silencing occurs. In particular, a significant fraction of internalized ONTs are nonproductively sequestered in endo-lysosomal compartments. Here, we describe a two-step, robust assay for high-throughput de novo detection of small bioactive molecules that enhance cellular uptake, endosomal escape, and efficacy of ONTs. Using this assay, we screened the LOPAC (Sigma-Aldrich) Library of Pharmacologically Active Compounds and discovered that Guanabenz acetate (Wytensin™), an FDA-approved drug formerly used as an antihypertensive agent, is capable of markedly increasing the cellular internalization and target mRNA silencing of hydrophobically modified siRNAs (hsiRNAs), yielding a ∼100-fold decrease in hsiRNA IC50 (from 132 nM to 2.4 nM). This is one of the first descriptions of a high-throughput small-molecule screen to identify novel chemistries that specifically enhance siRNA intracellular efficacy, and can be applied toward expansion of the chemical diversity of ONTs.
authors.affiliation: RNA Therapeutics Institute, Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Maire F
authors.initials: MF
authors.lastname: Osborn
authors.affiliation: RNA Therapeutics Institute, Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Julia F
authors.initials: JF
authors.lastname: Alterman
authors.affiliation: RNA Therapeutics Institute, Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Mehran
authors.initials: M
authors.lastname: Nikan
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Cao
authors.affiliation: RNA Therapeutics Institute, Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Marie C
authors.initials: MC
authors.lastname: Didiot
authors.affiliation: RNA Therapeutics Institute, Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Hassler
authors.affiliation: RNA Therapeutics Institute, Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA.
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Coles
authors.affiliation: RNA Therapeutics Institute, Department of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605, USA anastasia.khvorova@umassmed.edu.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Khvorova
mesh_terms: D001692:Biological Transport; D006143:Guanabenz / Q000737:chemistry / Q000494:pharmacology*; D006367:HeLa Cells; D057166:High-Throughput Screening Assays; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism*; D054852:Small Molecule Libraries; D013329:Structure-Activity Relationship
chemical_list: D034741:RNA, Small Interfering; D054852:Small Molecule Libraries; D006143:Guanabenz