Gene expression data of GBM146 and GBM157 at day0, 7, 30 after serum exposure

Glioblastoma (GBM) is a lethal brain cancer composed of heterogeneous cellular populations including glioma stem cells (GSCs) and their progeny differentiated non-stem glioma cells (NSGCs). Although accumulating evidence points out the significance of GSCs for tumour initiation and propagation, the roles of NSGCs remain elusive. Here we demonstrate that, when patient-derived GSCs in GBM tumours undergo differentiation with diminished telomerase activity and shortened telomeres, they subsequently become senescent phenotype, thereby secreting angiogenesis-related proteins, including vascular endothelial growth factors. Interestingly, these secreted factors from senescent NSGCs promote proliferation of human umbilical vein endothelial cells and tumorigenic potentials of GSCs in immunocompromised mice. These experimental data are likely clinically-relevant, since immunohistochemistry of both patient tumours of GBM and the patient GSC-derived mouse xenografted tumours detected tumour cells that express a set of markers for the senescence phenotype. Collectively, our data suggest that the inter-cellular signals from senescent NSGCs promote GBM tumour angiogenesis thereby increasing malignant progression of GBM.

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Ouchi R, Okabe S, Migita T, Nakano I, Seimiya H