Abstract 4773: Inhibition of mutant EGFR in lung cancer cells triggers SOX2-FOXO6 dependent survival pathways

Treatment of EGFR-mutant lung cancer with erlotinib results in dramatic tumor regression but it is invariably followed by drug resistance. In characterizing early transcriptional changes following drug treatment of mutant EGFR-addicted cells, we identified the stem cell transcriptional regulator SOX2 as being rapidly and specifically induced, both in vitro and in vivo. Suppression of SOX2 sensitizes cells to erlotinib-mediated apoptosis, whereas its ectopic expression reduces drug-induced cell death. We show that erlotinib relieves EGFR-dependent suppression of FOXO6, leading to SOX2 induction and repression of the pro-apoptotic BH3-only genes BIM and BMF. Together, these observations point to a physiological feedback mechanism that attenuates oncogene addiction-mediated cell death and may contribute to the acquisition of drug resistance. Citation Format: Stephen Michael Rothenberg, Kyle Concannon, Sarah Cullen, Alexa B. Turke, Anthony C. Faber, Jeffrey A. Engelman, Shyamala Maheswaran, Daniel A. Haber. Inhibition of mutant EGFR in lung cancer cells triggers SOX2-FOXO6 dependent survival pathways. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4773. doi:10.1158/1538-7445.AM2014-4773