TMOD-28. MODELING MICROENVIRONMENTAL DYNAMICS: A NOVEL 3D GLIOMA-NEURON FUSION MODEL

Abstract Gliomas engage in bidirectional interactions with their microenvironment, wherein neuronal activity influences glioma proliferation and gliomas induce neuronal hyperexcitability. Although various models elucidate this complex interplay, a preference for a three-dimensional (3D) cell culture model has emerged to mimic intra-tumoral heterogeneity and microenvironmental interactions influencing glioma invasion, resistance, and recurrence. This study introduces an in vitro, self-assembled, scaffold-free, neuron-glioma spheroid fusion model to investigate the electrophysiological and functional interplay between glioma and its microenvironment. Primary mouse cortical neurons (MCN) were isolated from prenatal brain tissues and were cultured at 500,000 cells/spheroid on ultra-low attachment plates. Glioma organoids (WHO Grade 2-4) were developed from primary patient-derived tissue samples and were allowed to self-assemble for at least two weeks. After spontaneous spiking activity was detected in MCN spheroids, they were combined with glioma organoids in culture and allowed to fuse. A multielectrode array (MEA) was used to characterize the electrophysiological properties of the fusion model. Structural and functional characterizations were performed using immunofluorescence staining of proliferation, microglial, astrocytic, synaptic, and tumor markers. Additionally, the electrophysiological effects of the dual-IDH-mutant inhibitor, Vorasidenib, were assessed in WHO grade 2-4 IDH-mutant gliomas. Electrophysiological analysis of glioma-neuron co-cultures using MEA demonstrated a significantly increased network synchrony and firing rate in the fusion model when compared with the neuron-only condition, consistent with 2D models in the past. In correlation, the fusion model also demonstrated a significant increase in the Ki67 proliferation index across WHO grade 2-4 gliomas when compared to the glioma organoid-only condition. Vorasidenib treatment decreased neuronal firing rate and synchrony. Together, these results offer a high-throughput 3D model for recapitulating the tumor-brain microenvironment for both low and high-grade gliomas. Future studies will focus on the use of this model for drug screening and the exploration of malignant transformation in gliomas.