Most non-small cell lung cancer (NSCLC) patients with epidermal growth factor (EGFR) mutations initially respond to EGFR tyrosine-kinase inhibitors (TKIs), but these inhibitors are only effective for approximately one year, thus limiting the benefits to patients' survival. Stratification of patients with EGFR-mutant NSCLC would help physicians personalize and optimize patient treatment plans. To this end, we hypothesized that factors residing in the tumor microenvironment play a pivotal role in the evolutionary dynamics of therapeutic response to anti-EGFR therapies. We used the Operetta® High Content Imaging System to track cell dynamics over time under different microenvironmental stresses, and we found that the growth of TKI-resistant cells is more sensitive to glucose starvation than TKI-sensitive cells. To further interrogate cellular metabolism in TKI-sensitive and resistant cells, we utilized both seahorse metabolic assays and fluorescence lifetime imaging microscopy to monitor the changes in glycolysis and oxidative phosphorylation of living cells. We found TKI-resistant cells have higher glycolysis and lower oxidative phosphorylation rates compared to TKI-sensitive cells. Such metabolic reprogramming rendered TKI-resistant cells with lower metabolic plasticity to cope with metabolic stress. Using both genetic and pharmacologic approaches, we then demonstrated that mTORC2 activation contributes to the different metabolic phenotypes between TKI-sensitive and resistant cells. Furthermore, gene set enrichment analysis showed that the oxidative phosphorylation gene set is significantly enriched in patients with low mTORC2 activation, and the glycolysis gene set is upregulated in patients with high mTORC2 activation, which is correlated with shorter progression-free and overall survival time in patients. Overall, these data suggest that TKI-resistant cells use and require distinct metabolic programs that can be employed to stratify EGFR-mutant NSCLC patients for treatment with EGFR-TKIs.
Citation Format: Chun-Te Chiang, Nolan Ung, Alexandra N. Demetriou, Chi-Li Chiu, Niha Choudhury, Cosimo Arnesano, Scott E. Fraser, David B. Agus, Naim Matasci, Dan L. Ruderman, Shannon M. Mumenthaler. Interrogating cellular metabolism reveals mTORC2 as a new biomarker to stratify epidermal growth factor receptor-mutant non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2414.