title: Notch1 stimulation induces a vascularization switch with pericyte-like cell differentiation of glioblastoma stem cells.
abstract: Glioblastoma multiforms (GBMs) are highly vascularized brain tumors containing a subpopulation of multipotent cancer stem cells. These cells closely interact with endothelial cells in neurovascular niches. In this study, we have uncovered a close link between the Notch1 pathway and the tumoral vascularization process of GBM stem cells. We observed that although the Notch1 receptor was activated, the typical target proteins (HES5, HEY1, and HEY2) were not or barely expressed in two explored GBM stem cell cultures. Notch1 signaling activation by expression of the intracellular form (NICD) in these cells was found to reduce their growth rate and migration, which was accompanied by the sharp reduction in neural stem cell transcription factor expression (ASCL1, OLIG2, and SOX2), while HEY1/2, KLF9, and SNAI2 transcription factors were upregulated. Expression of OLIG2 and growth were restored after termination of Notch1 stimulation. Remarkably, NICD expression induced the expression of pericyte cell markers (NG2, PDGFRβ, and α-smooth muscle actin [αSMA]) in GBM stem cells. This was paralleled with the induction of several angiogenesis-related factors most notably cytokines (heparin binding epidermal growth factor [HB-EGF], IL8, and PLGF), matrix metalloproteinases (MMP9), and adhesion proteins (vascular cell adhesion molecule 1 [VCAM1], intercellular adhesion molecule 1 [ICAM1], and integrin alpha 9 [ITGA9]). In xenotransplantation experiments, contrasting with the infiltrative and poorly vascularized tumors obtained with control GBM stem cells, Notch1 stimulation resulted in poorly disseminating but highly vascularized grafts containing large vessels with lumen. Notch1-stimulated GBM cells expressed pericyte cell markers and closely associated with endothelial cells. These results reveal an important role for the Notch1 pathway in regulating GBM stem cell plasticity and angiogenic properties.
authors.affiliation: Institut des Neurosciences de Montpellier, Hôpital St Eloi, Montpellier, Cedex, France.
authors.forename: Pierre-Olivier
authors.initials: PO
authors.lastname: Guichet
authors.forename: Sophie
authors.initials: S
authors.lastname: Guelfi
authors.forename: Marisa
authors.initials: M
authors.lastname: Teigell
authors.forename: Liesa
authors.initials: L
authors.lastname: Hoppe
authors.forename: Norbert
authors.initials: N
authors.lastname: Bakalara
authors.forename: Luc
authors.initials: L
authors.lastname: Bauchet
authors.forename: Hugues
authors.initials: H
authors.lastname: Duffau
authors.forename: Katrin
authors.initials: K
authors.lastname: Lamszus
authors.forename: Bernard
authors.initials: B
authors.lastname: Rothhut
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Hugnot
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D005909:Glioblastoma / Q000098:blood supply* / Q000378:metabolism / Q000473:pathology; D064593:Heterografts; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology*; D009389:Neovascularization, Pathologic / Q000378:metabolism / Q000473:pathology; D020286:Pericytes / Q000378:metabolism / Q000473:pathology*; D051881:Receptor, Notch1 / Q000378:metabolism*; D015398:Signal Transduction; D014162:Transfection
chemical_list: C497761:NOTCH1 protein, human; D051881:Receptor, Notch1
keywords: Glioblastoma; Glioma; Notch; Vascularization