Supplementary Figure S1. MIG6 protein reduction correlates with the responsiveness to ALK/ROS1 inhibitors. Supplementary Figure S2. MIG6 expression is decreased by ALK/ROS1 inhibition via the MAPK pathway. Supplementary Figure S3. Gefitinib restores sensitivity to ALK/ROS1 inhibition with MIG6 knockdown. Supplementary Figure S4. MIG6 siRNA knockdown rescues of SHC1-MAPK signaling under crizotinib treatments. Supplementary Figure S5. MIG6 mediates adaptive resistance to KRASG12C inhibition. Supplementary Figure S6. EGFR or ERBB2 amplification was not found in CUTO37-ER cells. Supplementary Figure S7. MIG6 protein is reduced in HCC78-TR and PR2 cells compared to their parental counterparts. Supplementary Figure S8. ERRFI1 alterations in pan-cancer. Supplementary Figure S9. Model depicting MIG6 role in regulating EGFR-mediated adaptive and acquired resistance to ALK/ROS1 inhibition.
Funding
National Cancer Institute (NCI)
United States Department of Health and Human Services
Find out more...the Addario Lung Cancer Medical Institute
the University of Colorado Lung SPORE
ARTICLE ABSTRACT
Despite the initial benefit from tyrosine kinase inhibitors (TKI) targeting oncogenic ALK and ROS1 gene fusions in non–small cell lung cancer, complete responses are rare and resistance ultimately emerges from residual tumor cells. Although several acquired resistance mechanisms have been reported at the time of disease progression, adaptative resistance mechanisms that contribute to residual diseases before the outgrowth of tumor cells with acquired resistance are less clear. For the patients who have progressed after TKI treatments, but do not demonstrate ALK/ROS1 kinase mutations, there is a lack of biomarkers to guide effective treatments. Herein, we found that phosphorylation of MIG6, encoded by the ERRFI1 gene, was downregulated by ALK/ROS1 inhibitors as were mRNA levels, thus potentiating EGFR activity to support cell survival as an adaptive resistance mechanism. MIG6 downregulation was sustained following chronic exposure to ALK/ROS1 inhibitors to support the establishment of acquired resistance. A higher ratio of EGFR to MIG6 expression was found in ALK TKI-treated and ALK TKI-resistant tumors and correlated with the poor responsiveness to ALK/ROS1 inhibition in patient-derived cell lines. Furthermore, we identified and validated a MIG6 EGFR-binding domain truncation mutation in mediating resistance to ROS1 inhibitors but sensitivity to EGFR inhibitors. A MIG6 deletion was also found in a patient after progressing to ROS1 inhibition. Collectively, this study identifies MIG6 as a novel regulator for EGFR-mediated adaptive and acquired resistance to ALK/ROS1 inhibitors and suggests EGFR to MIG6 ratios and MIG6-damaging alterations as biomarkers to predict responsiveness to ALK/ROS1 and EGFR inhibitors.
