Mechanistic insights into Yifei Sanjie pill's regulation of EMT to enhance gefitinib treatment effect in NSCLC by in silico analysis and experimental validation.

Ethnopharmacological Relevance: The Yi-Fei San-Jie pill (YFSJ) is a well-known Chinese medicine that has been used to treat non-small cell lung cancer in China for decades.

Aim Of The Study: Previous studies have shown that YFSJ combined with gefitinib can effectively inhibit the proliferation of gefitinib-resistant non-small cell lung cancer (NSCLC) cell lines by promoting apoptosis and autophagy, but the molecular biological mechanisms involved and whether YFSJ combined with gefitinib can have synergistic effects still need to be further explored. Thus, the present study aimed to establish an in silico and experimental framework to decipher the underlying mechanism by which YFSJ augments the efficacy of gefitinib in treating NSCLC.

Materials And Methods: Integrated approaches, including microarray analysis, network pharmacology, RNA sequencing, bioinformatics algorithm analysis and in vivo and in vitro experiments, were applied to elucidate the underlying mechanism.

Results: Analysis of microarray datasets indicated that gefitinib may play a role in the regulation of the epithelial-mesenchymal transition (EMT) of PC9 cells. EMT-related Gene Ontology (GO) terms and the MAPK pathway were found to be enriched in the differentially expressed genes (DEGs), and a decreasing trend was observed in the EMT score. Network pharmacology analysis revealed that the potential NSCLC-related targets of YFSJ also showed enrichment in EMT-related GO terms and the MAPK pathway. Experimental findings demonstrated that combined YFSJ-treated serum and gefitinib treatment significantly inhibited PC9 cell migration and invasion. In addition, the combined treatment dramatically reduced the tumour volume in an animal model. The effectiveness of the combination treatment surpassed that of gefitinib alone in both cell and animal experiments. RNA sequencing analysis revealed significant enrichment of DEGs in EMT-related GO terms for the gefitinib treatment group, YFSJ treatment group, and combination treatment group compared to the control group. Notably, the negative regulation of EMT showed significant enrichment in the DEGs of the combination treatment group. The MAPK pathway was significantly enriched among the different groups. Moreover, combined treatment with YFSJ and gefitinib may exert synergistic anti-NSCLC effects by inhibiting the p-p38 MAPK/GSK3β signalling axis, subsequently suppressing downstream EMT processes.

Conclusion: Combined treatment with YFSJ and gefitinib could enhance the sensitivity of NSCLC cells to gefitinib by suppressing EMT through the EGFR/p-p38 MAPK/GSK3β signalling axis. YFSJ may serve as an important adjunctive medication for NSCLC patients receiving gefitinib treatment in clinical practice.