Abstract
Purpose: Glioblastoma (GBM) is the most common and malignant form of primary human brain tumor in adults, with an average survival at diagnosis of 18 months. Metabolism is a new attractive therapeutic target in cancer; however, little is known about metabolic heterogeneity and plasticity within GBM tumors. We therefore aimed to investigate metabolic phenotyping of primary cultures in the context of molecular tumor heterogeneity to provide a proof of concept for person-alized metabolic targeting of GBM. Experimental Design: We have analyzed extensively several primary GBM cultures using transcriptomics, metabolic phe-notyping assays, and mitochondrial respirometry. Results: We found that metabolic phenotyping clearly identifies 2 clusters, GLN High and GLN Low , mainly based on metabolic plasticity and glutamine (GLN) utilization. Inhibition of glutamine metabolism slows the in vitro and in vivo growth of GLN High GBM cultures despite metabolic adaptation to nutrient availability, in particular by increasing pyruvate shuttling into mitochondria. Furthermore, phenotypic and molecular analyses show that highly pro-liferative GLN High cultures are CD133 neg and display a mesenchymal signature in contrast to CD133 pos GLN Low GBM cells. Conclusions: Our results show that metabolic pheno-typing identified an essential metabolic pathway in a GBM cell subtype, and provide a proof of concept for thera-nostic metabolic targeting. Clin Cancer Res; 1–13. Ó2017 AACR.