Steric disruption of EGFR oligomerization overcomes therapy resistance in non-small cell lung cancer.

Acquired drug resistance mutations in epidermal growth factor receptor (EGFR) present a substantial clinical challenge in treating non-small cell lung cancer (NSCLC). While EGFR oligomerization plays a pivotal role in modulating receptor signaling, its relationship with resistance mutations remains unclear. Here, we investigated the real-time link between oligomerization of oncogenic and resistant EGFR mutants and downstream signaling using a fluorescent protein-based proximity probe and signaling reporter in living cells. We found that EGFR mutants resistant to tyrosine kinase inhibitors (TKIs) exhibited higher oligomerization than did wild-type EGFR with or without EGF. The efficacy of TKIs and allosteric drugs inversely correlated with receptor oligomerization. Furthermore, sterically disrupting EGFR oligomerization by genetically fusing a bulky protein to resistant mutants overcame resistance and suppressed proliferation. Moreover, extracellular application of bulky EGFR binders suppressed resistant mutants by disrupting oligomerization. These findings highlight steric disruption of EGFR oligomerization as a promising strategy for overcoming therapy resistance in NSCLC and introduce a versatile screening platform for developing competitive and allosteric inhibitors.