title: Misprocessing and functional arrest of microRNAs by miR-Pirate: roles of miR-378 and miR-17.
abstract: miRNAs (microRNAs) are short non-coding RNAs that can regulate gene expression in cancer development, which makes them valuable targets for therapeutic intervention. In the present study we report on an approach that can not only arrest the functions of mature miRNAs by binding to them, but it can also induce the 'mis-processing' of the target miRNA, producing a non-functional truncated miRNA. This approach involves generating an expression construct that produces an RNA fragment with 16 repeat sequences. The construct is named miR-Pirate (miRNA-interacting RNA-producing imperfect RNA and tangling endogenous miRNA). The transcript of the construct contained mismatches to the seed region, and thus it would not target the potential targets of the miRNA under study. The homology of the construct is sufficiently high, allowing the transcript to block miRNA functions. The functions of the construct were validated in cell cultures, in tumour formation assays and in transgenic mice stably expressing this construct. To explore the possibility of adopting this approach in gene therapy, we transfected cells with synthetic miR-Pirate and obtained the results we expected. The miR-Pirate, expressed by the construct or synthesized chemically, was found to be able to specifically pirate and silence a mature miRNA through its dual roles and thus could be clinically applied for miRNA intervention.
authors.affiliation: Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada, M4N 3M5.
authors.forename: Zhaoqun
authors.initials: Z
authors.lastname: Deng
authors.forename: Xiangling
authors.initials: X
authors.lastname: Yang
authors.forename: Ling
authors.initials: L
authors.lastname: Fang
authors.forename: Zina J
authors.initials: ZJ
authors.lastname: Rutnam
authors.forename: Burton B
authors.initials: BB
authors.lastname: Yang
mesh_terms: D000818:Animals; D001483:Base Sequence; D045744:Cell Line, Tumor; D015870:Gene Expression; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014162:Transfection
chemical_list: C524941:MIRN17 microRNA, human; C526012:MIRN378 microRNA, human; C546119:MIRN378 microRNA, mouse; D035683:MicroRNAs; C543614:Mirn17 microRNA, mouse; D012333:RNA, Messenger