Abstract

This study investigated the role of anlotinib in restoring osimertinib sensitivity in EGFR-mutant non-small cell lung cancer (NSCLC) by targeting the Wnt/β-catenin/YAP signaling and PD-L1 expression. Using osimertinib-resistant HCC827 cells with high PD-L1 expression, a stable PD-L1 knockdown line (Sh-PD-L1) was generated through lentiviral vectors. Resistance was induced by stepwise exposure to osimertinib, and the two constructed resistant cell lines were named OR (osimertinib-resistant) and Sh-PD-L1-OR (PD-L1 knockdown osimertinib-resistant) cell lines. Functional assays, including wound healing, Transwell, and MTT, along with Western blot analysis, were conducted in both cell and animal models. Sh-PD-L1 significantly reduced PD-L1 and EGFR expression ( P < 0.001), decreased cell viability, and lowered IC50 values compared to parental cells ( P < 0.001). In OR, PD-L1 expression was elevated, and PD-L1 knockdown in the Sh-PD-L1-OR group reduced both PD-L1 and EGFR levels ( P < 0.001), enhanced YAP inhibition, and reversed Wnt/β-catenin signaling activation ( P < 0.05). Anlotinib treatment reduced cell viability, migration, and invasion, with enhanced effects in the Sh-PD-L1-OR group ( P < 0.001). It decreased p-EGFR, PD-L1, and YAP expression while activating GSK3β and reducing β-catenin phosphorylation ( P < 0.05). In vivo, anlotinib reduced tumor growth in Sh-PD-L1-OR models ( P < 0.01), with decreased expression of EGFR, PD-L1, YAP, and β-catenin. These findings suggest that high PD-L1 expression promotes osimertinib resistance through activation of YAP and Wnt/β-catenin, and that anlotinib combined with osimertinib can reverse resistance by restoring GSK3β activity, activating the Hippo pathway, and inhibiting β-catenin signaling.