title: miR-21 Is Linked to Glioma Angiogenesis: A Co-Localization Study.
abstract: MicroRNA-21 (miR-21) is the most consistently over-expressed microRNA (miRNA) in malignant gliomas. We have previously reported that miR-21 is upregulated in glioma vessels and subsets of glioma cells. To better understand the role of miR-21 in glioma angiogenesis and to characterize miR-21-positive tumor cells, we systematically stained consecutive serial sections from ten astrocytomas for miR-21, hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), phosphatase and tensin homolog (PTEN), octamer-binding transcription factor 4 (Oct4), sex-determining region Y box 2 (Sox2) and CD133. We developed an image analysis-based co-localization approach allowing global alignment and quantitation of the individual markers, and measured the miR-21 in situ hybridization signal against the immunohistochemical staining of the six different markers. miR-21 significantly co-localized with the hypoxia- and angiogenesis-associated markers HIF-1α (p=0.0020) and VEGF (p=0.0096), whereas the putative miR-21 target, PTEN, was expressed independently of miR-21. Expression of stem cell markers Oct4, Sox2 and CD133 was not associated with miR-21. In six glioblastoma cultures, miR-21 did not correlate with the six markers. These findings suggest that miR-21 is linked to glioma angiogenesis, that miR-21 is unlikely to regulate PTEN, and that miR-21-positive tumor cells do not possess stem cell characteristics.
authors.affiliation: Department of Pathology, Odense University Hospital, Denmark (SKH, CAJ, BWK)|Institute of Clinical Research, University of Southern Denmark (SKH, CAJ, BWK)
authors.forename: Simon Kjær
authors.initials: SK
authors.lastname: Hermansen
authors.affiliation: Bioneer A/S, Hørsholm, Denmark (BSN)
authors.forename: Boye Schnack
authors.initials: BS
authors.lastname: Nielsen
authors.affiliation: Department of Pathology, Odense University Hospital, Denmark (SKH, CAJ, BWK)|Institute of Clinical Research, University of Southern Denmark (SKH, CAJ, BWK)
authors.forename: Charlotte
authors.initials: C
authors.lastname: Aaberg-Jessen
authors.affiliation: Department of Pathology, Odense University Hospital, Denmark (SKH, CAJ, BWK)|Institute of Clinical Research, University of Southern Denmark (SKH, CAJ, BWK)
authors.forename: Bjarne Winther
authors.initials: BW
authors.lastname: Kristensen
mesh_terms: D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000098:blood supply / Q000473:pathology*; D001921:Brain / Q000098:blood supply / Q000473:pathology*; D001932:Brain Neoplasms / Q000098:blood supply / Q000235:genetics / Q000473:pathology*; D005260:Female; D005910:Glioma; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000032:analysis; D007091:Image Processing, Computer-Assisted; D017403:In Situ Hybridization; D008297:Male; D035683:MicroRNAs / Q000032:analysis*; D008875:Middle Aged; D014411:Neoplastic Stem Cells / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000473:pathology*; D051059:PTEN Phosphohydrolase / Q000032:analysis; D013194:Staining and Labeling; D042461:Vascular Endothelial Growth Factor A / Q000032:analysis
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D042461:Vascular Endothelial Growth Factor A; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human
keywords: MiR-21; angiogenesis; cancer stem cell; glioblastoma; glioma; in situ hybridization