Person:

Silverbush, Dana

High-grade gliomas are lethal brain cancers whose progression is robustly regulated by neuronal activity. Activity-regulated growth factor release promotes glioma growth, but this alone is insufficient to explain the effect that activity exerts on glioma progression. Here, we use single-cell transcriptomics, electron microscopy, whole-cell patch-clamp electrophysiology and calcium imaging to demonstrate that neuron-glioma interactions include electrochemical communication through bona fide AMPA receptor-dependent neuron-glioma synapses. Neuronal activity also evokes non-synaptic activity-dependent potassium currents that are amplified through gap junction-mediated tumor interconnections forming an electrically-coupled network. Glioma membrane depolarization assessed with in vivo optogenetics promotes proliferation, while pharmacologically or genetically blocking electrochemical signaling inhibits glioma xenograft growth and extends mouse survival. Emphasizing positive feedback mechanisms by which gliomas increase neuronal excitability and thus activity-regulated glioma growth, human intraoperative electrocorticography demonstrates increased cortical excitability in glioma-infiltrated brain. Together, these findings indicate that synaptic and electrical integration in neural circuits promotes glioma progression.

Single cell RNA-sequencing revealed extensive transcriptional cell state diversity in cancer, often observed independently from genetic heterogeneity, raising the central question of how malignant cell states are encoded epigenetically. To address this, we performed multi-omics single-cell profiling – integrating DNA methylation, transcriptome, and genotyping within the same cells – of diffuse gliomas, tumors governed by defined transcriptional cell state diversity. Direct comparison of the epigenetic profiles of distinct cell states revealed key switches for state transitions recapitulating neurodevelopmental trajectories, and highlighted dysregulated epigenetic mechanisms underlying gliomagenesis. We further developed a quantitative framework to measure cell state heritability and transition dynamics based on high resolution lineage trees directly in human samples. We demonstrated heritability of malignant cell states, with key differences in hierarchal vs. plastic cell state architectures in IDH-mutant glioma vs. IDH-wildtype glioblastoma, respectively. This work provides a novel framework anchoring transcriptional cancer cell states in their epigenetic encoding, inheritance and transition dynamics.