The secondary EGF receptor (EGFR) T790M is the most common mechanism of resistance to reversible EGFR-tyrosine kinase inhibitors (TKI) in patients with non-small cell lung cancer (NSCLC) with activating EGFR mutations. Although afatinib (BIBW2992), a second-generation irreversible EGFR-TKI, was expected to overcome the acquired resistance, it showed limited efficacy in a recent phase III clinical study. In this study, we found that the inhibition of glycolysis using 2-deoxy-d-glucose (2DG) improves the efficacy of afatinib in H1975 and PC9-GR NSCLC cells with EGFR T790M. Treatment with the combination of 2DG and afatinib induced intracellular ATP depletion in both H1975 and PC9-GR cells, resulting in activation of AMP-activated protein kinase (AMPK). AMPK activation played a central role in the cytotoxicity of the combined treatment with 2DG and afatinib through the inhibition of mTOR. The alteration of the AMPK/mTOR signaling pathway by the inhibition of glucose metabolism induced specific downregulation of Mcl-1, a member of the antiapoptotic Bcl-2 family, through translational control. The enhancement of afatinib sensitivity by 2DG was confirmed in the in vivo PC9-GR xenograft model. In conclusion, this study examined whether the inhibition of glucose metabolism using 2DG enhances sensitivity to afatinib in NSCLC cells with EGFR T790M through the regulation of the AMPK/mTOR/Mcl-1 signaling pathway. These data suggest that the combined use of an inhibitor of glucose metabolism and afatinib is a potential therapeutic strategy for the treatment of patients with acquired resistance to reversible EGFR-TKIs due to secondary EGFR T790M.
©2013 AACR.