Glutamatergic synaptic input to glioma cells drives brain tumour progression.

A network of communicating tumour cells that is connected by tumour microtubes mediates the progression of incurable gliomas. Moreover, neuronal activity can foster malignant behaviour of glioma cells by non-synaptic paracrine and autocrine mechanisms. Here we report a direct communication channel between neurons and glioma cells in different disease models and human tumours: functional bona fide chemical synapses between presynaptic neurons and postsynaptic glioma cells. These neurogliomal synapses show a typical synaptic ultrastructure, are located on tumour microtubes, and produce postsynaptic currents that are mediated by glutamate receptors of the AMPA subtype. Neuronal activity including epileptic conditions generates synchronised calcium transients in tumour-microtube-connected glioma networks. Glioma-cell-specific genetic perturbation of AMPA receptors reduces calcium-related invasiveness of tumour-microtube-positive tumour cells and glioma growth. Invasion and growth are also reduced by anaesthesia and the AMPA receptor antagonist perampanel, respectively. These findings reveal a biologically relevant direct synaptic communication between neurons and glioma cells with potential clinical implications.

Acyl-CoA-Binding Protein Drives Glioblastoma Tumorigenesis by Sustaining Fatty Acid Oxidation.

Glioblastoma multiforme (GBM) undergoes metabolic reprogramming to meet the high ATP and anabolic demands of the tumor cells. However, the role of fatty acid oxidation (FAO) and its regulators in the GBM context has been largely unknown. Here, we show that the neural stem cell pro-proliferative factor acyl-CoA-binding protein (ACBP, also known as DBI) is highly expressed in GBM, and by binding to acyl-CoAs, it cell-autonomously maintains high proliferation rates, promoting tumor growth and poor survival in several preclinical models. Mechanistic experiments using ACBP-acyl-CoA binding affinity variants and pharmacological FAO modulators suggest that ACBP supports tumor growth by controlling the availability of long-chain fatty acyl-CoAs to mitochondria, promoting FAO in GBM. Thus, our findings uncover a critical link between lipid metabolism and GBM progression established by ACBP and offer a potential therapeutic strategy for an effective anti-proliferative metabolic management of GBM.

GPD1 Specifically Marks Dormant Glioma Stem Cells with a Distinct Metabolic Profile.

Brain tumor stem cells (BTSCs) are a chemoresistant population that can drive tumor growth and relapse, but the lack of BTSC-specific markers prevents selective targeting that spares resident stem cells. Through a ribosome-profiling analysis of mouse neural stem cells (NSCs) and BTSCs, we find glycerol-3-phosphate dehydrogenase 1 (GPD1) expression specifically in BTSCs and not in NSCs. GPD1 expression is present in the dormant BTSC population, which is enriched at tumor borders and drives tumor relapse after chemotherapy. GPD1 inhibition prolongs survival in mouse models of glioblastoma in part through altering cellular metabolism and protein translation, compromising BTSC maintenance. Metabolomic and lipidomic analyses confirm that GPD1+ BTSCs have a profile distinct from that of NSCs, which is dependent on GPD1 expression. Similar GPD1 expression patterns and prognostic associations are observed in human gliomas. This study provides an attractive therapeutic target for treating brain tumors and new insights into mechanisms regulating BTSC dormancy.