Hesperidin Enhances the Antitumor Effect of Gefitinib Against Non-Small Cell Lung Cancer via Activation of Endoplasmic Reticulum Stress

Background: This study was designed to evaluate whether hesperidin (HES) could enhance the antitumor activity of gefitinib (GEF) against A549 non-small cell lung cancer (NSCLC) cells. Moreover, the molecular basis of this activity was also investigated using both in vitro and in vivo approaches. Methods: The viability of A549 cells treated with HES and GEF, alone or in combination, was assessed using the Cell Counting Kit-8 (CCK-8) assay to determine half-maximal inhibitory concentrations (IC50) and the suitable combination ratio. Cell morphology, migratory capacity, and apoptosis were examined by light microscopy, wound-healing assay, and flow cytometry, respectively. Expression levels of endoplasmic reticulum stress-related proteins, including ATF4 (activating transcription factor 4) and CHOP (C/EBP homologous protein), as well as cleaved caspase-3 were evaluated by Western blotting. An A549 xenograft model was established in nude mice to validate the antitumor efficacy and systemic safety of HES and GEF in vivo. Results: The IC50 values for HES and GEF in A549 cells were 153.1 μM and 30.28 μM, respectively. Compared with monotherapy, the HES/GEF combination induced pronounced morphological alterations, suppressed cell migration, and promoted apoptosis. This enhanced antitumor effect was associated with upregulation of ATF4, CHOP, and cleaved caspase-3 expression. In the xenograft model, combination therapy produced synergistic inhibition of tumor growth without inducing significant changes in body weight or major organ indices, indicating a favorable safety profile. Conclusion: HES synergizes with GEF to inhibit the malignant progression of A549 NSCLC cells, both in vitro and in vivo. The underlying mechanism may involve activation of endoplasmic reticulum stress-mediated apoptotic pathways.