CNSC-22. GLIOBLASTOMA CELLS EXHIBIT NEURON-LIKE EXCITABILITY IN BOTH ACUTE AND ORGANOTYPIC HUMAN BRAIN SLICES

Abstract Glioblastomas (GBM) are known for their significant intratumor heterogeneity, featuring a variety of plastic cell types that make effective treatment challenging. Recent studies have shown that neuronal-progenitor-like transcriptomic cell states at the leading edge of the tumor receive synaptic input from nearby neurons, which drives disease proliferation. However, the excitability of GBM cells remains controversial, with observations ranging from non-excitable to neuron-like excitability, complicating our understanding of their pathophysiology. In this study, we developed a novel experimental approach to study glioblastoma cells in both acute and cultured brain slices infiltrated with cancer from GBM patients. Using an adeno-associated virus for gene delivery, we selectively expressed fluorescent proteins in specific cell types. Fluorescence-guided whole-cell patch-clamp recordings were then used to analyze the electrophysiological properties of GBM cells and neurons within the tumor microenvironment. Our findings show that GBM cells have distinct electrophysiological properties, including a depolarized resting membrane potential (-31.95 ± 2.18 mV, n = 55 cells) and high membrane resistance (1.27 ± 0.19 GΩ, n = 62 cells). Approximately 56% of GBM cells at the tumor’s leading edge exhibited neuron-like excitability, generating aberrant action potentials (aAPs) upon depolarization. Collectively, our study provides direct evidence of the intrinsic excitability of GBM cells and a detailed characterization of their electrophysiological properties in the cancer-infiltrated human cortex. These insights shed new light on tumor heterogeneity and cell-cell interactions in glioblastoma, potentially guiding the development of targeted therapies.