Description
EGFR tyrosine kinase inhibitors cause dramatic responses in EGFR-mutant lung cancer, but resistance universally develops. The involvement of -catenin in EGFR TKI resistance has been previously reported however the precise mechanism by which -catenin activation contributes to EGFR TKI resistance is not clear. Here, we show that EGFR inhibition results in the activation of -catenin signaling in a Notch3-dependent manner, which facilitates the survival of a subset of cells that we call adaptive persisters. We previously reported that EGFR-TKI treatment rapidly activates Notch3, and here describe the physical association of Notch3 with -catenin, leading to increased stability and activation of -catenin. We demonstrate that the combination of EGFR-TKI and a -catenin inhibitor inhibits the development of these adaptive persisters, decreases tumor burden, improves recurrence free survival, and overall survival in xenograft models. These results supports combined EGFR-TKI and -catenin inhibition in patients with EGFR mutant lung cancer.