Introduction: Advances in tumor biology have established EGFR-tyrosine kinase inhibitors (EGFR-TKIs) as a key therapy for non-small cell lung cancer (NSCLC). Osimertinib (OSI), a third-generation EGFR-TKI, however, often leads to acquired resistance within about a year. Astragaloside IV (AS-IV), a bioactive saponin from Astragalus membranaceus, exhibits anti-tumor potential and may help reverse resistance-related epithelial–mesenchymal transition (EMT), a process mediated by TGF-β. While combining OSI with AS-IV is a promising strategy, its efficacy is limited by poor solubility and toxicity—challenges that can be addressed through liposomal co-delivery. Methods: We prepared OSI and AS-IV co-loaded liposomes (LPs-OSI/AS) and characterized their physicochemical properties and drug release in vitro. Cellular uptake and anti-proliferative effects were evaluated in OSI-sensitive (NCI-H1975) and OSI-resistant (NCI-H1975/AR) NSCLC cells. EMT-related gene expression was analyzed by RT-qPCR. In vivo efficacy was assessed using a subcutaneous xenograft model in BALB/c-nu mice by monitoring tumor growth and body weight. Results: LPs-OSI/AS liposomes were successfully prepared with uniform particle size (96.92 ± 12.04 nm, PDI 0.28 ± 0.01), high encapsulation efficiency (AS: 89.74 ± 6.53%; OSI: 84.35 ± 8.82%), and sustained release. In vitro, LPs-OSI/AS significantly inhibited proliferation of both NCI-H1975 and OSI-resistant NCI-H1975/OSIR cells, outperforming free drug controls without obvious cytotoxicity, and downregulated EMT-related genes ( Vimentin, TGFβ 1, TGFβ 2 ). In vivo, LPs-OSI/AS (20 mg/kg OSI + 40 mg/kg AS) reduced tumor volume by approximately 70% compared to OSI monotherapy, with 100% survival and no significant body weight loss. The Ki-67 positive rate was substantially lower in the LPs-OSI/AS group (1.06%) than in the OSI monotherapy group (5.98%), and H&E staining confirmed superior pathological improvement. Safety evaluation demonstrated normal organ structures with no inflammation or necrosis. Conclusion: In summary, LPs-OSI/AS effectively inhibits tumor growth by regulating EMT, exhibits favorable biosafety, and represents a promising therapeutic strategy for NSCLC. The image shows a biochemical pathway starting with Astragalus, which is converted to Astragaloside IV, then to AS-IV. AS-IV is combined with Osimertinib, a third-generation epidermal growth factor receptor tyrosine kinase inhibitor and liposome to form LPs-OSI/AS using PEG2000-DSPE. The LPs-OSI/AS is tested on NCI-H1975 and NCI-H1975/AR cells for cytotoxicity, colony formation and uptake. Reverse transcription quantitative polymerase chain reaction is used to analyze Vimentin, transforming growth factor beta 1 and transforming growth factor beta 2. In vivo testing involves BALB/c-nu mice, examining tumorigenesis, administration, dissection, tumor weight, tumor volume, hematoxylin and eosin staining and Ki-67 expression.Diagram: LPs-OSI/AS tested on OSI-sensitive and OSI-resistant NSCLC cells and subcutaneous xenograft mice. Keywords: NSCLC, EGFR-TKI, astragaloside IV, drug resistance
Mi et al. (Mon,) studied this question.