Extracellular Matrix Proteome Remodeling in Human Glioblastoma and Medulloblastoma

Medulloblastomas
(MBs) and glioblastomas (GBMs) are high-incidence
central nervous system tumors. Different origin sites and changes
in the tissue microenvironment have been associated with the onset
and progression. Here, we describe differences between the extracellular
matrix (ECM) signatures of these tumors. We compared the proteomic
profiles of MB and GBM decellularized tumor samples between each other
and their normal decellularized brain site counterparts. Our analysis
revealed that 19, 28, and 11 ECM proteins were differentially expressed
in MBs, GBMs, and in both MBs and GBMs, respectively. Next, we validated
key findings by using a protein tissue array with 53 MB and 55 GBM
cases and evaluated the clinical relevance of the identified differentially
expressed proteins through their analysis on publicly available datasets,
763 MB samples from the GSE50161 and GSE85217 studies, and 115 GBM
samples from RNAseq-TCGA. We report a shift toward a denser fibrillary
ECM as well as a clear alteration in the glycoprotein signature, which
influences the tumor pathophysiology. MS data have been submitted
to the PRIDE repository, project accession: PXD023350.