Monocarboxylate transporter 1 is a key player in glioma-endothelial cell crosstalk

Abstract

Glioblastoma (GBM) is one of the most glycolytic and angiogenic human tumours, characteristics that contribute to the poor prognosis associated with this type of tumour. A lactate shuttle has been described between tumour cells and endothelial cells (ECs), with the monocarboxylate transporters (MCTs) acting as important players in this tumour-EC communication. In this study, we aimed to understand how the tumour microenvironment modulates EC metabolism, and to characterize the role of MCTs in the glioma-brain EC crosstalk. Exposure of human brain microvascular ECs (HBMEC) to GBM cell-conditioned media increased the expression of MCT1, which corresponded to activation of oxidative metabolism and an increase in angiogenic capacity, as determined by increased proliferation, migration, and vessel assembly. Lactate depletion from the microenvironment or inhibition of lactate uptake in HBMEC induced an increase in lactate production and a decrease in proliferation, migration, and vessel assembly. Moreover, addition of lactate to HBMEC media promoted activation of AKT and AMPK pathways and increased expression in NFκB, HIF-1α, and the lactate receptor GPR81. Here, we demonstrate a role for MCT1 as a mediator of lactate signalling between glioma cells and brain ECs. Our results suggest that MCT1 can mediate EC metabolic reprograming, proliferation, and vessel sprouting in response to tumour signalling. Thus, targeting MCT1 in both tumour cells and brain EC may be a promising therapeutic strategy for the treatment of GBM. This article is protected by copyright. All rights reserved

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