Functional Analysis of Molecular Alterations in Brain Tumours: from fishing to function

Brain tumours consist of primary or de novo tumours, and secondary tumours. The latter group consists of metastasis derived from primary tumours at another location within the body, for example breast or lung. The primary brain tumours form a heterogeneous group of different tumour types with variable prognoses. In adults, the most common types of brain tumour are the meningiomas (mainly benign) and gliomas. In children, although gliomas occur, other tumours are more frequent and include primitive neuroectodermal tumours (PNETs) and medulloblastoma. Pilocytic astro‐cytomas and ependymomas, a specific type of glioma, also mainly occur in children

Mutation specific functions of EGFR result in a mutation-specific downstream pathway activation

Background: Epidermal growth factor receptor (EGFR) is frequently mutated in various types of cancer. Although all oncogenic mutations are considered activating, different tumour types have different mutation spectra. It is possible that functional differences underlie this tumour-type specific mutation spectrum. Methods: We have determined whether specific mutations in EGFR (EGFR, EGFRvIII and EGFR-L858R) have differences in binding partners, differences in downstream pathway activation (gene expression and phosphoproteins), and have functional consequences on cellular growth and migration. Results: Using biotin pulldown and subsequent mass spectrometry we were able to detect mutation specific binding partners for EGFR. Differential binding was confirmed using a proximity ligation assay and/or Western Blot for the dedicator of cytokinesis 4 (DOCK4), UDP-glucose glycoprotein glucosyltransferase 1 (UGGT1), MYC binding protein 2 (MYCBP2) and Smoothelin (SMTN). We also demonstrate that each mutation induces the expression of a specific set of genes, and that each mutation is associated with specific phosphorylation patterns. Finally, we demonstrate using stably expressing cell lines that EGFRvIII and EGFL858R display reduced growth and migration compared to EGFR ildtype expressing cells