CNSC-28. CELLULAR AND FUNCTIONAL REMODELING OF HUMAN CEREBRAL ORGANOIDS BY GLIOBLASTOMA STEM-LIKE CELLS

Abstract

Abstract The burgeoning field of cancer neuroscience focuses on deciphering the role of normal neural cells in brain tumor growth. Until recently, representation of normal human neural cells in brain tumor model systems was lacking. By utilizing human induced-pluripotent stem cells derived cerebral organoids (COs) co-cultured with glioblastoma stem-like cells (RFP-luciferase tagged MDA-GSCs, n = 3 representing each glioblastoma molecular sub-type), we investigated the effects of GSCs on CO-derived neural cells and their activity. COs and CO+MDA-GSCs were subjected to single-cell RNA-sequencing (scRNA-seq). As per typical micro-anatomy of COs, neural stem/progenitor cells are interiorly distributed whereas differentiated neurons are positioned on the surfaces, enabling measurement of neuronal action potential on surfaces of COs by micro-electrode arrays (MEA). The scRNA-seq data from CO+MDA-GSC samples were subset into CO-derived (luciferase-ve) and GSCs-derived (luciferase+ve). Compared with COs, co-cultured samples had significantly higher percentage of non-telencephalon neural progenitor cells (ntNPCs) (CO_vs._CO+MDA-GSC(luciferase-ve): 15.6% vs. 47.2%-63.4%) while the percentages of cortical NPC (cNPCs) and intermediate progenitors (IPs) was lower (CO_vs._CO+MDA-GSC(luciferase-ve): 39.2% vs. 12.0%-20.5%). These alterations in NPC/IPs abundance were accompanied by decreased proportions of cortical excitatory neurons (CO_vs._CO+MDA-GSC(Luciferase-ve): 33.2% vs. 7.9%-23.4%). Among luciferase+ve MDA-GSCs-derived cells in co-culture samples, mesenchymal MDA-GSCs had higher abundance of ntNPCs versus cNPCs (30.4% versus 63.6%) whereas, among classical and proneural MDA-GSCs ntNPCs were 11.45-22.8 times higher. Interestingly, 14.9% of proneural MDA-GSCs derived cells displayed inhibitory neuron signatures. After 3 weeks, the mean firing rate measured by MEA was significantly lower in co-cultures compared to COs (CO_vs._CO+MDA-GSC: 0.052 Hz vs. 0.0081 Hz p-value 0.000219), suggesting functional remodeling. Our results show that cellular remodeling of normal cells resulted in progenitor-like cell-state whereas that of MDA-GSCs varied across molecular sub-type. These results suggest interactions between normal and tumor cells can potentially be leveraged to manage brain tumor growth and its impact on normal brain.