BACKGROUND: Amplification of the epidermal growth factor receptor (EGFR) and its mutant EGFRvIII are among the most common genetic alterations in glioblastoma (GBM), the most frequent and most aggressive primary brain tumor. METHODS: In the present work, we analyzed the clonal evolution of these major EGFR aberrations in a small cohort of GBM patients using a unique surgical multisampling technique. Furthermore, we overexpressed both receptors separately and together in 2 patient-derived GBM stem cell lines (GSCs) to analyze their functions in vivo in orthotopic xenograft models. RESULTS: In human GBM biopsies, we identified EGFR amplification as an early event because EGFRvIII mutations emerge from intratumoral heterogeneity later in tumor development. To investigate the biological relevance of this distinct developmental pattern, we established experimental model systems. In these models, EGFR(+) tumor cells showed activation of classical downstream signaling pathways upon EGF stimulation and displayed enhanced invasive growth without evidence of angiogenesis in vivo. In contrast, EGFRvIII(+) tumors were driven by activation of the prototypical Src family kinase c-Src that promoted VEGF secretion leading to angiogenic tumor growth. CONCLUSIONS: The presented work shows that sequential EGFR amplification and EGFRvIII mutations might represent concerted evolutionary events that drive the aggressive nature of GBM by promoting invasion and angiogenesis via distinct signaling pathways. In particular, c-SRC may be an attractive therapeutic target for tumors harboring EGFRvIII as we identified this protein specifically mediating angiogenic tumor growth downstream of EGFRvIII.

• MeSH
• analýza přežití MeSH
• erbB receptory genetika   metabolismus   MeSH
• glioblastom diagnostické zobrazování   genetika   metabolismus   patologie   MeSH
• invazivní růst nádoru MeSH
• lidé MeSH
• molekulární evoluce MeSH
• mozek diagnostické zobrazování   patologie   MeSH
• multimodální zobrazování MeSH
• mutace MeSH
• nádorové buněčné linie MeSH
• nádory mozku diagnostické zobrazování   genetika   metabolismus   patologie   MeSH
• patologická angiogeneze metabolismus   MeSH
• protoonkogenní proteiny pp60(c-src) metabolismus   MeSH
• upregulace MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• fosfotyrosin metabolismus   MeSH
• kur domácí MeSH
• molekulární modely MeSH
• onkogenní protein pp60(v-src) genetika   chemie   metabolismus   MeSH
• protoonkogenní proteiny pp60(c-src) chemie   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH