Glioblastoma cells imitate neuronal excitability in humans

BackgroundGlioblastomas are renowned for their pronounced intratumoral heterogeneity, characterized by a diverse array of plastic cell types. However, the physiological and transcriptomic features of the cells residing in the invasive leading edge (LE), including both neurons and glioblastoma cells (GBCs), remain unclear, challenging our comprehension of the glioblastoma pathophysiology. MethodsTo elucidate molecular and morphophysiological features of LE cells, we established an experimental workflow enabling the investigation of GBCs and neurons within cancer-infiltrated organotypic tissue specimens from the same patients. With this approach, we characterized the electrophysiological properties of cells in the neocortical tumor LE (LE cells). We further performed single-cell Patch-seq experiments, enabling transcriptomic analysis of electrophysiologically recorded LE cells. ResultsUpon depolarization, 58% of LE cells exhibited aberrant action potentials (aAPs). Electrophysiological assessment showed that a subset of GBCs generated aAPs, with no significant differences in aAP properties compared to LE neurons. Transcriptomic analysis of 144 LE cells revealed four transcriptomic clusters, including two GBC populations and two neuronal populations. LE GBCs exhibited diverse cellular states, including mesenchymal-like, astrocyte-like, neural progenitor-like, and oligodendrocyte-precursor cell-like phenotypes. Notably, LE GBCs exhibiting aAPs displayed reduced mitotic pathway activity and developmental regulatory ion channel CaV1.2. Cell-cell interaction analysis illustrates a higher signaling interaction between aAP LE cells compared to no-aAP LE cells. ConclusionIn summary, we find comparable electrical properties between neurons and a subset of GBCs in the leading edge, suggesting an active electrophysiological role of GBCs in the tumors pathophysiology. Key PointsO_LIHuman organotypic slice cultures enable long-term functional investigation of glioblastoma cells. C_LIO_LIGBCs and neurons in the LE exhibit similar aAPs. C_LIO_LILE GBCs display heterogeneous cellular states, with reduced proliferation signaling in aAP GBCs. C_LI Importance of studyThis study sheds light on the diverse pathophysiological and molecular features of cells in the neocortical infiltration zone of glioblastoma. By utilizing in vitro organotypic human brain slice cultures, a reliable platform for longitudinal observation, we unveiled the dichotomy of the electrical properties of LE cells. More than half of LE cells display aAP, contradicting findings from cultured tumor cells and animal models. Patch-seq analysis confirmed that both GBCs and neurons in the LE generate aAPs with indistinguishable electrical properties. aAP GBCs showed higher cell-cell interactions. We find aAP GBCs to express reduced proliferation signaling compared to no-aAP GBCs, suggesting a non-dividing and potentially more plastic cell state. These findings point to the electrical-active GBCs as an important attribute of the LE, linking the electrophysiological properties with functional implications, and implicate an active role of electrophysiological changes of GBCs in tumor pathophysiology.