Abstract 5433: β-Tubulin inhibitors reduce GLUT1 membrane trafficking to attenuate tumorigenesis in glioblastoma subtypes

Abstract

Abstract Glioblastoma is an aggressive, high-grade tumor with poor prognosis due to lack of sound therapeutic options. Mesenchymal subtype GBMs are particularly difficult to treat because they tend to proliferate in the sub ventricular zone, an area that breeds stem-like neural cells and proves nearly impossible to access for surgical resection. They also contribute to creating a hypoxic microenvironment and switch to glycolytic metabolism in what is known as the Warburg Effect. Here, we hypothesize that strategically inhibiting the glucose transporter, GLUT1, through cytoskeletal components that traffic it to the cell membrane may reverse the Warburg Effect, attenuating further tumorigenesis and decreasing the stemness of such cells. Datamining studies and immunoblot analysis conducted on human glioblastoma patient specimens (hGBM) demonstrated that GLUT1 is highly upregulated. Limiting dilution assay conducted using GLUT1 inhibitors- fasentin and 2-Deoxy-D-glucose reduced the proliferation in mesenchymal cancer stem cell (CSC) subtype in in vitro culture. Simultaneously, mass spectrometric analysis revealed significant association between GLUT1 and β-tubulin 4 (TUBB4) in mesenchymal subtyped cells. This association was further confirmed by large-sample datamining and in immunoprecipitation studies from hGBM specimens, suggesting that TUBB4 may be a viable target in deterring the trafficking of upregulated GLUT1 to the membrane. Collectively, these studies confirm that GLUT1 is associated with TUBB4, and that targeting TUBB4 via siRNA or colchicine derivatives could prove effective in reversing the Warburg Effect in GBM cells and ultimately improve patient outcomes. Citation Format: Collin M. Labak, Maheedhara R. Guda, Swapna Asuthkar, Neha Jain, Yining Lu, Ian Purvis, Jack Tuszynski, Ichiro Nakano, Andrew J. Tsung, Kiran K. Velpula. β-Tubulin inhibitors reduce GLUT1 membrane trafficking to attenuate tumorigenesis in glioblastoma subtypes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5433. doi:10.1158/1538-7445.AM2017-5433