title: Regulation of human RNase-L by the miR-29 family reveals a novel oncogenic role in chronic myelogenous leukemia.
abstract: The endoribonuclease RNase-L is the terminal component of an interferon-regulated RNA decay pathway known as the 2'-5'-oligoadenylate (2-5A) system, whose established functions include antimicrobial and tumor suppressive activities. RNase-L activity requires binding of the small molecule 2-5A, leading to RNase-L dimerization and cleavage of single-stranded RNA. RNase-L expression is controlled post-transcriptionally by its 3'-untranslated region (3' UTR), which exerts a strong negative effect on RNase-L levels. MicroRNAs (miRNAs) are a class of small noncoding RNAs that repress expression of target genes by binding to regions of complementarity often in the 3' UTR. The miR-29 family acts as a tumor suppressor in several cancers, including acute and chronic myelogenous leukemia (CML), and has many oncogenic targets. We report that the miR-29 family represses RNase-L protein expression across several cell types. Using a luciferase reporter, we showed that miR-29 acts via 4 target sites within the RNASEL 3' UTR. Mutation of all sites is required for abrogation of miR-29 repression. In light of the reported tumor suppressive role of miR-29 in K562 CML cells and miR-29 repression of RNase-L in these cells, we generated K562 cells with stable RNase-L knockdown and demonstrated that loss of RNase-L inhibits proliferation in vitro as well as tumor growth in a xenograft model. Our findings identify a previously unknown miRNA regulator of RNase-L expression and support a novel oncogenic role for RNase-L in CML and potentially other hematopoietic malignancies.
authors.affiliation: Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
authors.forename: Teresa Y
authors.initials: TY
authors.lastname: Lee
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Ezelle
authors.forename: Thiagarajan
authors.initials: T
authors.lastname: Venkataraman
authors.forename: Rena G
authors.initials: RG
authors.lastname: Lapidus
authors.forename: Kara A
authors.initials: KA
authors.lastname: Scheibner
authors.forename: Bret A
authors.initials: BA
authors.lastname: Hassel
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D015153:Blotting, Western; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004722:Endoribonucleases / Q000235:genetics* / Q000378:metabolism; D005260:Female; D015973:Gene Expression Regulation, Leukemic; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D020014:K562 Cells; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D047368:Tumor Burden / Q000235:genetics; D023041:Xenograft Model Antitumor Assays
chemical_list: D020413:3' Untranslated Regions; C532045:MIRN29a microRNA, human; D035683:MicroRNAs; D008156:Luciferases; D004722:Endoribonucleases; C031956:2-5A-dependent ribonuclease