Abstract 1900: A tension-mediated glycocalyx feedback loop promotes glioblastoma

Abstract

Abstract A considerable challenge in glioblastoma (GBM) therapy is treatment resistance and tumor recurrence, resulting in dismal patient prognosis. GBM aggression and recurrence is often associated with a mesenchymal phenotype, increased expression of glycoproteins and the presence of glioma-initiating “stem-like” cells. Using patient-derived xenograft models, and immune competent syngeneic and transgenic glioma mouse models, we show that aggressive mesenchymal-like GBMs, reminiscent of recurrent GBM, are mechanically stiffer, present with a bulky glycocalyx and demonstrate a stem-like phenotype. We report that the more aggressive mesenchymal GBMs show increased mechanical signaling and contractility, and their tumors are surrounded by a stiffer ECM that maintains and even further enhances integrin mechanosignaling. Since a large proportion of these bulky glycoproteins are also stem markers, upregulation of the glycoproteins and their modulators leads to enhanced GBM stem-ness. This was evident both in our mesenchymal models of GBM as well as multiple patient datasets which compared paired primary and recurrent GBM RNA sequencing and protein data. In addition to stem-ness, we show that the mechanically “enhanced” GBMs also foster a differential immune landscape, infiltrated by type 2 macrophages, believed to be pro-tumorigenic and immune evasive. Our findings suggest that there is a dynamic and reciprocal link between integrin mechanosignaling, the GBM immune landscape and a bulky glycocalyx, which promotes a mesenchymal, stem-like phenotype and likely recurrence in GBM patients. Thus, therapeutic strategies to target GBM tissue tension could prevent recurrence, reduce mortality and improve patient outcome. Citation Format: Shelly Kaushik, James Matthew Barnes, Russell O. Bainer, Jason K. Sa, Elliot C. Woods, Fuiboon Kai, Jonathon N. Lakins, Joanna J. Phillips, Valerie M. Weaver. A tension-mediated glycocalyx feedback loop promotes glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1900.