title: MicroRNA-21 targets tumor suppressor genes ANP32A and SMARCA4.
abstract: MicroRNA-21 (miR-21) is a key regulator of oncogenic processes. It is significantly elevated in the majority of human tumors and functionally linked to cellular proliferation, survival and migration. In this study, we used two experimental-based strategies to search for novel miR-21 targets. On the one hand, we performed a proteomic approach using two-dimensional differential gel electrophoresis (2D-DIGE) to identify proteins suppressed upon enhanced miR-21 expression in LNCaP human prostate carcinoma cells. The tumor suppressor acidic nuclear phosphoprotein 32 family, member A (ANP32A) (alias pp32 or LANP) emerged as the most strongly downregulated protein. On the other hand, we applied a mathematical approach to select correlated gene sets that are negatively correlated with primary-miR-21 (pri-miR-21) expression in published transcriptome data from 114 B-cell lymphoma cases. Among these candidates, we found tumor suppressor SMARCA4 (alias BRG1) together with the already validated miR-21 target, PDCD4. ANP32A and SMARCA4, which are both involved in chromatin remodeling processes, were confirmed as direct miR-21 targets by immunoblot analysis and reporter gene assays. Furthermore, knock down of ANP32A mimicked the effect of enforced miR-21 expression by enhancing LNCaP cell viability, whereas overexpression of ANP32A in the presence of high miR-21 levels abrogated the miR-21-mediated effect. In A172 glioblastoma cells, enhanced ANP32A expression compensated for the effects of anti-miR-21 treatment on cell viability and apoptosis. In addition, miR-21 expression clearly increased the invasiveness of LNCaP cells, an effect also seen in part upon downregulation of ANP32A. In conclusion, these results suggest that downregulation of ANP32A contributes to the oncogenic function of miR-21.
authors.affiliation: Institute of Clinical Immunology, Medical Faculty, University of Leipzig, Leipzig, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Schramedei
authors.forename: N
authors.initials: N
authors.lastname: Mörbt
authors.forename: G
authors.initials: G
authors.lastname: Pfeifer
authors.forename: J
authors.initials: J
authors.lastname: Läuter
authors.forename: M
authors.initials: M
authors.lastname: Rosolowski
authors.forename: J M
authors.initials: JM
authors.lastname: Tomm
authors.forename: M
authors.initials: M
authors.lastname: von Bergen
authors.forename: F
authors.initials: F
authors.lastname: Horn
authors.forename: K
authors.initials: K
authors.lastname: Brocke-Heidrich
mesh_terms: D001483:Base Sequence; D002470:Cell Survival / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D002478:Cells, Cultured; D004265:DNA Helicases / Q000235:genetics* / Q000378:metabolism; D015536:Down-Regulation; D005786:Gene Expression Regulation; D018390:Gene Targeting; D016147:Genes, Tumor Suppressor; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D016601:RNA-Binding Proteins; D038621:Regulatory Sequences, Ribonucleic Acid / Q000235:genetics / Q000502:physiology; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D057825:Two-Dimensional Difference Gel Electrophoresis
chemical_list: C087425:ANP32A protein, human; D047908:Intracellular Signaling Peptides and Proteins; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D038621:Regulatory Sequences, Ribonucleic Acid; D014157:Transcription Factors; C084108:SMARCA4 protein, human; D004265:DNA Helicases