An EGFR-induced Drosophila lung tumor model identifies alternative combination treatments

Lung cancer is the leading cause of cancer-associated mortality. Mutations in the epidermal growth factor receptor (EGFR) gene are among the most important inducers of lung tumor development, but success of personalized therapies is still limited due to toxicity or developing resistances. We expressed constitutively active EGFR (EGFRCA) exclusively in the airway system of Drosophila melanogaster and performed comprehensive phenotyping. Ectopic expression of EGFRCA induced massive hyper- and metaplasia, leading to early death. We used the lethal phenotype as a read-out and screened a library of FDA-approved compounds and found that among the 1000 compounds only the tyrosine kinase inhibitors afatinib, gefitinib and ibrutinib rescued lethality in a whole animal screening approach. Furthermore, we screened the library in the presence of a sub-therapeutic afatinib dose and identified bazedoxifene as a synergistically acting compound that rescues EGFR-induced lethality. Our findings highlight the potential of Drosophila-based whole animal screening approaches to not only identify specific EGFR inhibitors but also to discover compounds that act synergistically with known TKIs. Moreover, we showed that targeting the EGFR together with STAT-signaling is a promising strategy for lung tumor treatment.