Shuyu Wan Potentiates PD-1 Inhibitor Efficacy in Non-Small Cell Lung Cancer: Integrated Bioinformatics and Experimental Evidence for Gut Microbiota-Tumor Immune Crosstalk.

BACKGROUND: Therapeutic heterogeneity limits the efficacy of immune checkpoint inhibitors (ICIs) in non-small cell lung cancer (NSCLC). Shuyu Wan (SYW), a classic TCM formula, has shown potential in modulating gut microbiota (GM) and enhancing immunotherapy, yet its synergistic mechanism with PD-1 inhibitors remains unclear.

MATERIALS AND METHODS: SYW components were identified by UPLC-MS. NSCLC-related targets were integrated with SYW targets for pathway enrichment, and molecular docking validated component-target binding. NSCLC syngeneic mice were treated with SYW and/or PD-1 inhibitor (RMP1-14). Tumor growth, histopathology, serum cytokines, tumor-infiltrating CD8+T cell subsets (flow cytometry), PD-1/PD-L1 expression and co-localization (immunofluorescence), GM composition (16S rRNA), and metabolomics were assessed. FMT verified the role of GM-TME crosstalk.

RESULTS: SYW monotherapy showed no significant tumor inhibition, whereas SYW combined with PD-1 inhibitor dose-dependently suppressed NSCLC growth. The combination reduced PD-1 expression and PD-1/PD-L1 co-localization, elevated serum IL-12, IFN-γ, and TNF-α, increased total tumor-infiltrating CD8+ T cells, decreased PD-1+ and TIM-3+ exhausted subsets, and expanded IFN-γ+ and Granzyme B+ effector subsets. Concurrently, it reshaped GM (increased Bacillota, decreased Patescibacteria) and altered metabolites (L-glycine, L-proline). These effects were abolished in antibiotic treated mice and restored by FMT, suggesting GM-TME crosstalk as essential.

CONCLUSION: SYW acts as a microbiota-dependent immune sensitizer that potentiates PD-1 inhibitor efficacy in NSCLC by remodeling GM and enhancing effector CD8+ T cell infiltration while reducing exhaustion. GM-TME crosstalk is the potential mechanism, supporting SYW as an adjunct to PD-1 blockade in NSCLC therapy.