title: Pleiotropic effects of miR-183~96~182 converge to regulate cell survival, proliferation and migration in medulloblastoma.
abstract: Medulloblastomas are the most common malignant brain tumors in children. Several large-scale genomic studies have detailed their heterogeneity, defining multiple subtypes with unique molecular profiles and clinical behavior. Increased expression of the miR-183~96~182 cluster of microRNAs has been noted in several subgroups, including the most clinically aggressive subgroup associated with genetic amplification of MYC. To understand the contribution of miR-183~96~182 to the pathogenesis of this aggressive subtype of medulloblastoma, we analyzed global gene expression and proteomic changes that occur upon modulation of miRNAs in this cluster individually and as a group in MYC-amplified medulloblastoma cells. Knockdown of the full miR-183~96~182 cluster results in enrichment of genes associated with apoptosis and dysregulation of the PI3K/AKT/mTOR signaling axis. Conversely, there is a relative enrichment of pathways associated with migration, metastasis and epithelial to mesenchymal transition, as well as pathways associated with dysfunction of DNA repair in cells with preserved miR-183 cluster expression. Immunocytochemistry and FACS analysis confirm induction of apoptosis upon knockdown of the miR-183 cluster. Importantly, cell-based migration and invasion assays verify the positive regulation of cell motility/migration by the miR-183 cluster, which is largely mediated by miR-182. We show that the effects on cell migration induced by the miR-183 cluster are coupled to the PI3K/AKT/mTOR pathway through differential regulation of AKT1 and AKT2 isoforms. Furthermore, we show that rapamycin inhibits cell motility/migration in medulloblastoma cells and phenocopies miR-183 cluster knockdown. Thus, the miR-183 cluster regulates multiple biological programs that converge to support the maintenance and metastatic potential of medulloblastoma.
authors.affiliation: Department of Neurology, Children's Hospital Boston and Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Shyamal Dilhan
authors.initials: SD
authors.lastname: Weeraratne
authors.forename: Vladimir
authors.initials: V
authors.lastname: Amani
authors.forename: Natalia
authors.initials: N
authors.lastname: Teider
authors.forename: Jessica
authors.initials: J
authors.lastname: Pierre-Francois
authors.forename: Dominic
authors.initials: D
authors.lastname: Winter
authors.forename: Min Jeong
authors.initials: MJ
authors.lastname: Kye
authors.forename: Soma
authors.initials: S
authors.lastname: Sengupta
authors.forename: Tenley
authors.initials: T
authors.lastname: Archer
authors.forename: Marc
authors.initials: M
authors.lastname: Remke
authors.forename: Alfa H C
authors.initials: AH
authors.lastname: Bai
authors.forename: Peter
authors.initials: P
authors.lastname: Warren
authors.forename: Stefan M
authors.initials: SM
authors.lastname: Pfister
authors.forename: Judith A J
authors.initials: JA
authors.lastname: Steen
authors.forename: Scott L
authors.initials: SL
authors.lastname: Pomeroy
authors.forename: Yoon-Jae
authors.initials: YJ
authors.lastname: Cho
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D002453:Cell Cycle / Q000235:genetics; D045744:Cell Line, Tumor; D054443:Cell Migration Assays; D002465:Cell Movement / Q000235:genetics*; D049109:Cell Proliferation; D002528:Cerebellar Neoplasms / Q000473:pathology; D020552:Comet Assay; D019295:Computational Biology; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D055785:Gene Knockdown Techniques; D006801:Humans; D008527:Medulloblastoma / Q000473:pathology; D035683:MicroRNAs / Q000235:genetics*; D040901:Proteomics; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics*; D014162:Transfection
chemical_list: C533449:MIRN183 microRNA, human; C541492:MIRN96 microRNA, human; C489427:MYC protein, human; D035683:MicroRNAs; C538984:Mirn182 microRNA, human; D016271:Proto-Oncogene Proteins c-myc