Abstract 5838: Development of metabolic-targeting therapy for overcoming resistance to osimertinib in non-small cell lung cancer cells
Authors: Serizawa Masakuni , Umehara Rina , Ohshima Keiichi , Urakami Kenichi , Nagashima Takeshi , Yamaguchi Ken , Kaira Kyoichi , Takahashi Toshiaki , Kusuhara Masatoshi 
Published: August 2018

Abstract
Background: The third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), osimertinib, is effective against patients with non-small-cell lung cancer (NSCLC) showing EGFR T790M-induced resistance to first generation EGFR-TKIs. Moreover, the potential of osimertinib as an effective initial therapy for treatment-naïve patients with NSCLC harboring EGFR-activating mutations has been reported. Unfortunately, cases of acquired osimertinib resistance exist, and the involvement of genetic alterations such as EGFR C797S mutation and MET amplification has been reported, although the resistance mechanisms are not fully understood. We have previously demonstrated that first-generation EGFR-TKI-resistant NSCLC cells possess altered metabolic pathways, which might be targeted for therapy to overcome this resistance. Therefore, we aimed to identify the metabolic profile relevant to osimertinib-resistance and develop a targeted therapy for the altered metabolic signature.
Methods: Osimertinib-resistant cell lines were generated by exposing HCC827 cells harboring the EGFR-activating mutation to increasing osimertinib concentrations (OSR1, OSR2). Moreover, we selected erlotinib-resistant cell lines that also showed osimertinib-resistance (EOSR1, EOSR2) from previously generated erlotinib-resistant cells obtained by prolonged exposure of HCC827 to erlotinib. Whole-exome sequencing, gene expression profiling, and metabolic profiling were performed to identify the genetic, gene expression, and metabolic signatures associated with osimertinib resistance, respectively. The growth-inhibitory effect of the inhibitors was evaluated by the WST assay.
Results: Four osimertinib-resistant cell lines showed resistance to whole-generation EGFR-TKIs, namely erlotinib, afatinib and osimertinib. EGFR T790M or C797S mutations were not detected, while MET amplification was commonly observed in these resistant cell lines. These cells also contained higher concentrations of fructose 1, 6-bisphosphate and lactic acid than HCC827, possibly because of a significant increase in hexokinase expression. Activation of the pentose phosphate pathway and subsequent nucleotide metabolism were also observed in the OSR cells, but not in the EOSR cells. A combination of a competitive glycolytic inhibitor, 2-deoxy-D-glucose (2-DG), and osimertinib restored osimertinib sensitivity in the EOSR cells showing glycolysis dependence, but not in the OSR cells.
Conclusions: Four resistant cell lines showed the same genetic alteration, namely, MET gene amplification; however, the metabolic signature and response to the 2-DG-osimertinib combination differed between the EOSR and OSR cells. Stratification based on tumor metabolic signature may contribute to the selection of promising therapeutic strategies for overcoming osimertinib resistance.
Citation Format: Masakuni Serizawa, Rina Umehara, Keiichi Ohshima, Kenichi Urakami, Takeshi Nagashima, Ken Yamaguchi, Kyoichi Kaira, Toshiaki Takahashi, Masatoshi Kusuhara. Development of metabolic-targeting therapy for overcoming resistance to osimertinib in non-small cell lung cancer cells [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 5838.