DDDR-16. SORTING TO ENRICH FOR CHEMOTHERAPEUTIC-RESISTANT GLIOMA CELLS BASED ON UNIQUE MEMBRANE PROPERTIES

Abstract

Abstract Glioblastoma, astrocytoma, and oligodendroglioma comprise a class of aggressive and deadly brain tumors called diffuse gliomas. Around 20,000 glioma cases are diagnosed yearly in the US alone. The current standard chemotherapy treatment, temozolomide (TMZ), is insufficient as the 5-year survival rate of glioblastoma patients is as low as 8%. This is due to the presence of TMZ-resistant cells within tumors that lead to chemoresistance and tumor recurrence. Thus, studying the molecular properties of TMZ-resistant cells would enable more effective means of targeting them and thus improve patient outcomes. We leveraged dielectrophoresis (DEP), a phenomenon by which non-uniform electric fields induce differential movement of cells, as a novel label-free technique to sort glioma cells based on their membrane electrophysiological properties. We were able to successfully use DEP to sort cells from glioblastoma and oligodendroglioma established cell lines, which yielded fractions that differed in membrane capacitance, the membrane’s ability to store charge. Interestingly, the DEP-sorted cell fractions also exhibited significant differences in TMZ resistance, indicating that we were able to use DEP to enrich for TMZ-resistant cells. Further, the differences in TMZ resistance were coupled with their membrane capacitance differences. Because we previously found that changes in membrane capacitance were linked to differences in glycosylation, we utilized lectin analysis to assess glycan expression of DEP-sorted oligodendroglioma cells. Our data show that TMZ-resistant oligodendroglioma cells enriched from DEP sorting had reduced levels of mannose glycans compared to less TMZ-resistant fractions. Collectively, our novel findings demonstrate (a) TMZ-resistant glioma cells can be enriched by DEP, and (b) TMZ resistance is correlated with membrane capacitance and cell surface glycosylation. These findings could enable further characterization of TMZ-resistant cells to better understand molecular mechanisms of TMZ resistance and the development of more effective treatment strategies for gliomas through targeting membrane properties such as glycosylation.