title: Critical role of miR-9 in myelopoiesis and EVI1-induced leukemogenesis.
abstract: MicroRNA-9 (miR-9) is emerging as a critical regulator of organ development and neurogenesis. It is also deregulated in several types of solid tumors; however, its role in hematopoiesis and leukemogenesis is not yet known. Here we show that miR-9 is detected in hematopoietic stem cells and hematopoietic progenitor cells, and that its expression increases during hematopoietic differentiation. Ectopic expression of miR-9 strongly accelerates terminal myelopoiesis and promotes apoptosis in vitro and in vivo. Conversely, in hematopoietic progenitor cells, the inhibition of miR-9 with a miRNA sponge blocks myelopoiesis. Ecotropic viral integration site 1 (EVI1), required for normal embryogenesis, is considered an oncogene because its inappropriate up-regulation induces malignant transformation in solid and hematopoietic cancers. Here we show that EVI1 binds to the promoter of miR-9-3, leading to DNA hypermethylation of the promoter and repression of miR-9. Moreover, miR-9 expression reverses a myeloid differentiation block that is induced by EVI1. Our findings indicate that EVI1, when inappropriately expressed, delays or blocks myeloid differentiation at least in part by DNA hypermethylation and down-regulation of miR-9. It was reported that Forkhead box class O genes (FoxOs) inhibit myeloid differentiation and prevent differentiation of leukemia-initiating cells. Here we identify both FoxO1 and FoxO3 as direct targets of miR-9 in hematopoietic cells and find that up-regulation of FoxO3 inhibits miR-9-induced myelopoiesis. These results reveal a unique role of miR-9 in myelopoiesis and in the pathogenesis of EVI1-induced myeloid neoplasms and provide insights into the epigenetic regulation of miR9 in tumorigenesis.
authors.affiliation: Department of Medicine, and Cancer Research Center, University of Illinois, Chicago, IL 60621, USA.
authors.forename: Vitalyi
authors.initials: V
authors.lastname: Senyuk
authors.forename: Yunyuan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Ming
authors.initials: M
authors.lastname: Ming
authors.forename: Kavitha
authors.initials: K
authors.lastname: Premanand
authors.forename: Lan
authors.initials: L
authors.lastname: Zhou
authors.forename: Ping
authors.initials: P
authors.lastname: Chen
authors.forename: Jianjun
authors.initials: J
authors.lastname: Chen
authors.forename: Janet D
authors.initials: JD
authors.lastname: Rowley
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Nucifora
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Qian
mesh_terms: D000818:Animals; D047369:Chromatin Immunoprecipitation; D003114:Colony-Forming Units Assay; D019175:DNA Methylation; D017931:DNA Primers / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005434:Flow Cytometry; D000071161:Forkhead Box Protein O1; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics*; D057809:HEK293 Cells; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D000074008:MDS1 and EVI1 Complex Locus Protein; D051379:Mice; D035683:MicroRNAs / Q000378:metabolism*; D038042:Myelopoiesis / Q000235:genetics / Q000502:physiology*; D041681:NIH 3T3 Cells; D011519:Proto-Oncogenes; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D017931:DNA Primers; D004268:DNA-Binding Proteins; C085126:FOXO1 protein, human; C499517:FOXO3 protein, human; D000071161:Forkhead Box Protein O1; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D000074008:MDS1 and EVI1 Complex Locus Protein; C063575:MECOM protein, human; C541874:MIRN92 microRNA, human; D035683:MicroRNAs; D014157:Transcription Factors