title: Guanine analogues enhance antisense oligonucleotide-induced exon skipping in dystrophin gene in vitro and in vivo.
abstract: Exon skipping has demonstrated great potential for treating Duchenne muscular dystrophy (DMD) and other diseases. We have developed a drug-screening system using C2C12 myoblasts expressing a reporter green fluorescent phosphate (GFP), with its reading frame disrupted by the insertion of a targeted dystrophin exon. A library of 2,000 compounds (Spectrum collection; Microsource Discovery System) was screened to identify drugs capable of skipping targeted dystrophin exons or enhancing the exon-skipping effect by specific antisense oligomers. The 6-thioguanine (6TG) was effective for inducing skipping of both human dystrophin exon 50 (hDysE50) and mouse dystrophin exon 23 (mDysE23) in the cell culture systems and increased exon skipping efficiency (more than threefolds) when used in combination with phosphorodiamidate morpholino oligomers (PMO) in both myoblasts and myotubes. Guanine and its analogues were unable to induce detectable skipping of exon 23 when used alone but enhanced PMO-induced exon skipping significantly (approximately two times) in the muscles of dystrophic mdx mouse in vivo. Our results demonstrate that small-molecule compounds could enhance specific exon skipping synergistically with antisense oligomers for experimental therapy to human diseases.
authors.affiliation: Department of Neurology, McColl-Lockwood Laboratory for Muscular Dystrophy Research, Neuromuscular/ALS Center, Carolinas Medical Center, Charlotte, North Carolina 28231, USA.
authors.forename: Yihong
authors.initials: Y
authors.lastname: Hu
authors.forename: Bo
authors.initials: B
authors.lastname: Wu
authors.forename: Allen
authors.initials: A
authors.lastname: Zillmer
authors.forename: Peijuan
authors.initials: P
authors.lastname: Lu
authors.forename: Ehsan
authors.initials: E
authors.lastname: Benrashid
authors.forename: Mingxing
authors.initials: M
authors.lastname: Wang
authors.forename: Timothy
authors.initials: T
authors.lastname: Doran
authors.forename: Mona
authors.initials: M
authors.lastname: Shaban
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Wu
authors.forename: Qi Long
authors.initials: QL
authors.lastname: Lu
mesh_terms: D017398:Alternative Splicing / Q000187:drug effects*; D000818:Animals; D004353:Drug Evaluation, Preclinical; D016189:Dystrophin / Q000235:genetics*; D005091:Exons / Q000235:genetics*; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics; D006147:Guanine / Q000031:analogs & derivatives*; D006801:Humans; D051379:Mice; D018101:Mice, Inbred mdx; D009025:Morpholines / Q000494:pharmacology; D060172:Morpholinos; D018485:Muscle Fibers, Skeletal / Q000187:drug effects; D020388:Muscular Dystrophy, Duchenne / Q000628:therapy*; D032446:Myoblasts / Q000187:drug effects; D020319:Oligodeoxyribonucleotides, Antisense / Q000235:genetics*; D054852:Small Molecule Libraries; D013866:Thioguanine / Q000494:pharmacology*
chemical_list: D016189:Dystrophin; D009025:Morpholines; D060172:Morpholinos; D020319:Oligodeoxyribonucleotides, Antisense; D054852:Small Molecule Libraries; D049452:Green Fluorescent Proteins; D006147:Guanine; D013866:Thioguanine