Altered Glutamine Metabolism Exposes EMT Derived Mesenchymal Cells to PI3K/Akt/mTOR Pathway Inhibition

Background: Epithelial-to-mesenchymal transition (EMT) is a fundamental developmental process with strong implications in cancer progression. Understanding the metabolic alterations associated with EMT may open new avenues of treatment and prevention.Methods: We utilize 13C carbon analogs of glucose and glutamine to examine difference in internal flux patterns of metabolites in central carbon and lipid metabolism following EMT in breast epithelial cell lines. Furthermore, an isotopomer spectral analysis, 13C-metabolic flux analysis and weighted correlation network analysis are utilized for investigation of the alterations in metabolic functionality following EMT in breast.Results: There are inherent differences in metabolic profiles before and after EMT. We observed EMT-dependent re-routing of TCA-cycle flux characterized by increased mitochondrial IDH2 -mediated reductive carboxylation of glutamine to lipid biosynthesis with a concomitant lowering of glycolytic rates and glutamine-dependent glutathione (GSH) generation. Our network approach identified specific subtype of cancer drugs that are significantly associated with GSH abundance and we confirmed this in vitro.Conclusions: EMT-linked alterations in GSH synthesis modulate the sensitivity of breast epithelial cells to PI3K/Akt/mTOR inhibitors.