A pomalidomide-based gefitinib PROTAC degrader effectively inhibits lung cancer progression in EGFR-TKIs-acquired resistant models by targeting EGFR degradation and ETFA-mediated ATP generation

Activating mutations in EGFR confer sensitivity to EGFR-TKIs and are associated with improved outcomes. However, resistance develops due to a secondary mutation in EGFR, limiting the benefits of lung cancer patients with EGFR-TKIs. There is an urgent need of improved therapeutics for lung cancer patients harboring EGFR activating mutation. Here we report an EGFR proteolysis-targeting chimeric (PROTAC) degrader, P-G, that induces EGFR degradation both in non-small cell lung cancer (NSCLC) cells with EGFR activating mutation and corresponding TKIs-acquired resistant cells to avoid drug resistance. Furthermore, by introducing pomalidomide to gefitinib, P-G not only triggers EGFR degradation but also sensitizes cancer cells to programmed cell death, as pomalidomide targets electron transfer flavoprotein subunit alpha (ETFA) to enhance energy production for promoting apoptosis. We found that P-G induced robust and persistent EGFR degradation both in EGFR-TKIs-acquired resistant HCC-827 cells and parental cells, with the effect lasting for more than 72 h after drug removal. Moreover, P-G effectively bound to and thermally stabilized ETFA, thus enhancing energy production in EGFR-TKI acquired resistance models. Mechanistic studies revealed that P-G triggered EGFR degradation via ubiquitin-proteasome-dependent proteolysis and autophagy-lysosome activation pathways. P-G significantly suppressed tumor growth in a gefitinib-acquired resistant HCC-827 xenograft model with favorable biosafety profile in vivo. This work highlights the potential of EGFR-PROTAC degrader (P-G) as an innovative therapeutic strategy of targeting EGFR degradation and ETFA-mediated ATP generation, providing direction for the development of targeted cancer therapy.