Treatment-induced tumor dormancy through YAP-mediated transcriptional reprogramming of the apoptotic pathway [YAP1 KO vs CTRL]

Eradicating tumor dormancy that develops following oncogene-targeted therapy, including after epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) treatment of EGFR-mutant non-small cell lung cancer (NSCLC), is an attractive therapeutic strategy but the mechanisms governing the establishment of tumor dormancy are poorly understood. We observe that blockade of ERK1/2 reactivation following EGFR TKI treatment by combined EGFR/MEK inhibition uncovers cells that survive by entering a senescence-like dormant state, characterized by extensive epigenetic remodeling and high YAP/TEAD activity. YAP/TEAD trigger an epithelial-to-mesenchymal transition (EMT) program and engage the EMT transcription factor SLUG to directly repress pro-apoptotic BMF, limiting drug-induced apoptosis. Pharmacological co-inhibition of YAP or TEAD, or genetic deletion of YAP1, all deplete dormant cells by enhancing EGFR/MEK induced apoptosis. Thus, YAP activation can promote the survival of EGFR-mutant NSCLC cells in the chronic absence of EGFR signaling. Eradicating this population enhances the efficacy of targeted therapies which could ultimately lead to prolonged treatment responses in cancer patients.