Cancer Letters

Cancer Letters

Volume 434, 10 October 2018, Pages 152-159
Cancer Letters

Original Articles
mTORC2 contributes to the metabolic reprogramming in EGFR tyrosine-kinase inhibitor resistant cells in non-small cell lung cancer

https://doi.org/10.1016/j.canlet.2018.07.025Get rights and content
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Highlights

  • The growth rate of erlotinib-resistant cells is sensitive to glucose deprivation.

  • Erlotinib-resistant cells have diminished spare respiratory capacity.

  • mTORC2 contributes to metabolic reprogramming in erlotinib-resistant cells.

  • mTORC2 activation correlates with clinical outcome of EGFR-mutated NSCLC patients.

Abstract

Non-small cell lung cancer (NSCLC) patients with activating EGFR mutations are often successfully treated with EGFR tyrosine kinase inhibitor (TKI) such as erlotinib; however, treatment resistance inevitably occurs. Given tumor metabolism of glucose and therapeutic response are intimately linked, we explored the metabolic differences between isogenic erlotinib-sensitive and -resistant NSCLC cell lines. We discovered that the growth of erlotinib-resistant cells is more sensitive to glucose deprivation. Seahorse metabolic assay revealed erlotinib-resistant cells have lower spare respiratory capacity (SRC), an indicator of metabolic flexibility, compared to erlotinib-sensitive cells. Additionally, we found downstream components of mTORC2 signaling to be phosphorylated in erlotinib-resistant cells. Knockdown of an mTORC2 component, Rictor, enhanced the SRC and rescued the growth rate of erlotinib-resistant cells during glucose deprivation. Among NSCLCs with activating EGFR mutations, gene sets involved in glucose metabolism were enriched in patients with high expression of p-NDGR1, a readout of mTORC2 activity. Furthermore, overall survival was negatively correlated with p-NDRG1. Our work uncovers a link between mTORC2 and metabolic reprogramming in EGFR TKI-resistant cells and highlights the significance of mTORC2 in the progression of EGFR-mutated NSCLC.

Keywords

NSCLC
EGFR TKI resistance
Glucose metabolism
mTORC2

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