title: OTX2 exhibits cell-context-dependent effects on cellular and molecular properties of human embryonic neural precursors and medulloblastoma cells.
abstract: Medulloblastoma (MB) is the most common malignant primary pediatric brain tumor and is currently divided into four subtypes based on different genomic alterations, gene expression profiles and response to treatment: WNT, Sonic Hedgehog (SHH), Group 3 and Group 4. This extensive heterogeneity has made it difficult to assess the functional relevance of genes to malignant progression. For example, expression of the transcription factor Orthodenticle homeobox2 (OTX2) is frequently dysregulated in multiple MB variants; however, its role may be subtype specific. We recently demonstrated that neural precursors derived from transformed human embryonic stem cells (trans-hENs), but not their normal counterparts (hENs), resemble Groups 3 and 4 MB in vitro and in vivo. Here, we tested the utility of this model system as a means of dissecting the role of OTX2 in MB using gain- and loss-of-function studies in hENs and trans-hENs, respectively. Parallel experiments with MB cells revealed that OTX2 exerts inhibitory effects on hEN and SHH MB cells by regulating growth, self-renewal and migration in vitro and tumor growth in vivo. This was accompanied by decreased expression of pluripotent genes, such as SOX2, and was supported by overexpression of SOX2 in OTX2+ SHH MB and hENs that resulted in significant rescue of self-renewal and cell migration. By contrast, OTX2 is oncogenic and promotes self-renewal of trans-hENs and Groups 3 and 4 MB independent of pluripotent gene expression. Our results demonstrate a novel role for OTX2 in self-renewal and migration of hENs and MB cells and reveal a cell-context-dependent link between OTX2 and pluripotent genes. Our study underscores the value of human embryonic stem cell derivatives as alternatives to cell lines and heterogeneous patient samples for investigating the contribution of key developmental regulators to MB progression.
authors.affiliation: Regenerative Medicine Program, Departments of Biochemistry & Medical Genetics and Physiology & Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3E 0J9.
authors.forename: Ravinder
authors.initials: R
authors.lastname: Kaur
authors.affiliation: Regenerative Medicine Program, Departments of Biochemistry & Medical Genetics and Physiology & Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3E 0J9.
authors.forename: Christopher
authors.initials: C
authors.lastname: Aiken
authors.affiliation: Regenerative Medicine Program, Departments of Biochemistry & Medical Genetics and Physiology & Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3E 0J9.
authors.forename: Ludivine Coudière
authors.initials: LC
authors.lastname: Morrison
authors.affiliation: Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Biology and Regenerative Medicine (inStem), NCBS-TIFR Campus, GKVK PO, Bellary Road, Bangalore 560065, India.
authors.forename: Radhika
authors.initials: R
authors.lastname: Rao
authors.affiliation: Department of Pathology, University of Manitoba, 401 Brodie Centre, 727 McDermot Avenue, Winnipeg, Manitoba, Canada, R3E 3P5 Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Marc R
authors.initials: MR
authors.lastname: Del Bigio
authors.affiliation: Centre for Inflammation and Tissue Homeostasis, Institute for Stem Cell Biology and Regenerative Medicine (inStem), NCBS-TIFR Campus, GKVK PO, Bellary Road, Bangalore 560065, India.
authors.forename: Shravanti
authors.initials: S
authors.lastname: Rampalli
authors.affiliation: Regenerative Medicine Program, Departments of Biochemistry & Medical Genetics and Physiology & Pathophysiology, University of Manitoba, Winnipeg, Manitoba, Canada, R3E 0J9 Tamra.ogilvie@umanitoba.ca.
authors.forename: Tamra
authors.initials: T
authors.lastname: Werbowetski-Ogilvie
mesh_terms: D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D000066673:Cell Self Renewal; D002470:Cell Survival; D015536:Down-Regulation; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D053263:Gene Regulatory Networks; D000066449:Human Embryonic Stem Cells / Q000378:metabolism*; D006801:Humans; D008527:Medulloblastoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D008954:Models, Biological; D058953:Neural Stem Cells / Q000378:metabolism* / Q000473:pathology; D051857:Otx Transcription Factors / Q000378:metabolism*; D039904:Pluripotent Stem Cells / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D055748:SOXB1 Transcription Factors / Q000378:metabolism; D059467:Transcriptome / Q000235:genetics
chemical_list: C497659:OTX2 protein, human; D051857:Otx Transcription Factors; D012333:RNA, Messenger; D055748:SOXB1 Transcription Factors
keywords: Brain tumor modeling; Human embryonic stem cells; Medulloblastoma; OTX2; hESCs