Ankyrin Repeat Domain 1 Overexpression is Associated with Common Resistance to Afatinib and Osimertinib in EGFR-mutant Lung Cancer

Overcoming acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) is critical in combating EGFR-mutant non-small cell lung cancer (NSCLC). We tried to construct a novel therapeutic strategy to conquer the resistance to second-and third-generation EGFR-TKIs in EGFR-positive NSCLC patients. We established afatinib- and osimertinib-resistant lung adenocarcinoma cell lines. Exome sequencing, cDNA array and miRNA microarray were performed using the established cell lines to discover novel therapeutic targets associated with the resistance to second-and third-generation EGFR-TKIs. We found that ANKRD1 which is associated with the epithelial-mesenchymal transition (EMT) phenomenon and anti-apoptosis, was overexpressed in the second-and third-generation EGFR-TKIs-resistant cells at the mRNA and protein expression levels. When ANKRD1 was silenced in the EGFR-TKIs-resistant cell lines, afatinib and osimertinib could induce apoptosis of the cell lines. Imatinib could inhibit ANKRD1 expression, resulting in restoration of the sensitivity to afatinib and osimertinib of EGFR-TKI-resistant cells. In EGFR-mutant NSCLC patients, ANKRD1 was overexpressed in the tumor after the failure of EGFR-TKI therapy, especially after long-duration EGFR-TKI treatments. ANKRD1 overexpression which was associated with EMT features and anti-apoptosis, was commonly involved in resistance to second-and third-generation EGFR-TKIs. ANKRD1 inhibition could be a promising therapeutic strategy in EGFR-mutant NSCLC patients.