Diffuse gliomas are primary brain tumors including glioblastomas (GB), astrocytomas, and oligodendrogliomas, the latter two harboring IDH1 mutations and exhibiting slower progression. Gliomas display cellular plasticity, with transitions between astrocyte-like, oligodendrocyte-like, progenitor-like, and mesenchymal-like states driven by genetic alterations and microenvironmental signals. The proneural-to-mesenchymal transition (PMT), associated with increased malignancy, is tightly regulated by the tumor microenvironment, notably through cytokine signaling and non-tumor cell interactions. Endothelins (ET-1, ET-2, ET-3), vasoactive peptides mainly produced by vascular cells, signal through the G-protein-coupled receptors EDNRA and EDNRB and were previously suggested to promote glioma proliferation based on serum-based models. Here, we revisited endothelin signaling using eleven serum-free glioma lines and tumor samples. Multi-omics and electrophysiological analyses identified EDNRB as the predominant receptor, enriched in astrocyte-like cells, increased by BMPs or growth factor withdrawal, and repressed by interferons, IL-6 family cytokines, endothelins, and Hippo/YAP signaling. EDNRA was confined to a perivascular tumor subpopulation and induced by Notch signaling selectively in GB. Functionally, endothelins reduced proliferation while promoting migration and PMT via EDNRB-dependent Ca2+ signaling, ERK/STAT3 activation, and apamin-sensitive SK2/SK3 potassium channel activity. Collectively these findings establish endothelin signaling as an important regulator of glioma cell plasticity and behavior.
Pineau et al. (Thu,) studied this question.