Association of Notch-1, osteopontin and stem-like cells in ENU-glioma malignant process

// Susana Bulnes 1 , Garazi Bermudez 2 and Jose Vicente Lafuente 1, 3, 4 1 LaNCE, Department of Neuroscience, University of the Basque Country (UPV/EHU), Leioa, Spain 2 Neurosurgery Service, Cruces University Hospital, Barakaldo, Spain 3 Nanoneurosurgery Group, Institute of Health Research Biocruces, Barakaldo, Spain 4 Faculty of Health Science, Universidad Autonoma de Chile, Santiago de Chile, Chile Correspondence to: Susana Bulnes, email: susana.bulnes@ehu.eus Keywords: angiogenesis; glioma stem-like cells; N-ethyl-N-nitrosourea; Notch-1; osteopontin Received: October 07, 2017      Accepted: July 12, 2018      Published: July 31, 2018 ABSTRACT Notch-1 and osteopontin (OPN) mediate angiogenesis and glioma stem-like cell (GSLC) maintenance. However, the relationship between these molecules and GSLCs during the development of glioma is unknown. We investigate the expression of Notch-1, OPN and vascular endothelial growth factor (VEGF) associated to the stemness markers nestin and CD133 in three stages of murine gliomas induced by N-ethyl-N-nitrosourea (ENU). Notch-1 and OPN overexpress in the intermediate stage (II), which corresponds to the “angiogenesis switch”. Nestin+ cells appear in all stages of ENU-glioma but CD133 only from stage II on. In stage III, neoplastic cells expressing nestin, CD133 and nestin/CD133 reside in spheroid-like aggregates (SAs) and in the neoangiogenic border. These aggregates show Notch-1 and VEGF+ surrounding cells and a significant size and density increase with respect to stage I (3.3 ± 1.5 to 22.4 ± 6.3 μm 2 , no = 0.3 ± 0.1 to 4.2 ± 0.9, from stage I to stage III, respectively). OPN expression increases in correlation to the glioma malignancy from 4.5 ± 1.8% (I) to 12.3 ± 1.2% of OPN+ cells (III). It predominates in astrocyte-like cells of the neoangiogenic border, displaying co-location with VEGF and CD133. The OPN immunopositivity distribution correlates with the CD133 distribution. In conclusion, OPN co-expressing with CD133 contributes to the identification of GSLCs in the neoangiogenic border, while Notch-1 is present around SAs in advanced stages. The ENU-glioma, mainly in stage II, is a useful tool for assessing new antitumour therapies against these molecules.