GPR56/ADGRG1 inhibits Mesenchymal Differentiation and Radioresistance in Glioblastoma

A mesenchymal transition occurs both during natural evolution of glioblastoma (GBM) and in response to therapy. However, the molecular mechanisms underlying mesenchymal differentiation are not well understood. We have found that the adhesion G protein-coupled receptor, GPR56/ADGRG1, inhibits mesenchymal differentiation and radioresistance in glioblastoma stem-like initiating cells (GICs). Here, we have performed microarray analysis of control- versus GPR56 knockdown-GICs to characterize gene expression changes upon GPR56 knockdown and identify a gene expression signature associated to GPR56. To identify a GPR56-associated gene signature we compared the gene expression profile of control- and GPR56 knockdown-GICs by genome-wide microarray analysis. Patient-derived CD44low GICs (control- and GPR56 knockdown-GICs) were cultured under adherent conditions on laminin in serum-free neural stem cell medium (in the presence of bFGF and EGF) at 37°C, 5% CO2 and 5% oxygen. Total RNA was extracted, labeled and hybridized in a SurePrint G3 Human GE 8x60k array (Agilent Technologies). Four paired biological replicates of each control- and GPR56 knockdown-GICs were used.