Periostin (POSTN) Regulates Tumor Resistance to Antiangiogenic Therapy in Glioma Models

Periostin (POSTN) interacts with multiple integrins to coordinate a variety of cellular processes, including epithelial-to-mesenchymal transition (EMT) and cell migration. In our previous study, anti-VEGF-A therapy was associated with resistance and EMT. This study sought to determine the role of POSTN in the resistance of glioma stem cells (GSC) to antiangiogenic therapy. In mouse xenograft models of human glioma, POSTN expression was associated with acquired resistance to anti-VEGF-A therapy and had a synergistic effect with bevacizumab in prolonging survival and decreasing tumor volume. Resistance to anti-VEGF-A therapy regulated by POSTN was associated with increased expression of TGF beta 1 and hypoxia-inducible factor-1 alpha (HIF1 alpha) in GSCs. At the molecular level, POSTN regulated invasion and expression of EMT (caveolin-1) and angiogenesis-related genes (HIF1 alpha and VEGF-A) through activation of STAT3. Moreover, recombinant POSTN increased GSC invasion. Collectively, our findings suggest that POSTN plays an important role in glioma invasion and resistance to antiangiogenic therapy. (C)2016 AACR.