Shuangshen granules enhance anti-PD1 therapy effectiveness in lung adenocarcinoma by modulating myeloid-derived suppressor cell-induced T cell exhaustion.

Background: Worldwide, lung cancer is the most common cause of cancer-related deaths. Molecular targeted therapies and immunotherapies for non-small-cell lung cancer (NSCLC) have improved outcomes markedly over the past two decades. However, the vast majority of advanced NSCLCs become resistant to current treatments and eventually progress. A traditional Chinese medicine (TCM) formula of Shuangshen granules (SSG) has demonstrated potential in alleviating cancer side effects and improving survival rate. Despite clinical evidence supporting its benefit, there is still insufficient understanding of the active compounds in SSG and their underlying mechanisms, which limits its broader clinical application.

Methods: Lewis lung carcinoma (LLC) tumor-bearing mouse model was established to assess the efficacy of combined SSG and anti-PD-1 therapy in vivo, and myeloid-derived suppressor cells (MDSC) and CD8⁺T cells were isolated for in vitro co-culture experiments, while pathological examination was conducted using hematoxylin and eosin (HE). The expression of PD-1, TIM-3, CTLA-4, LAG-3, Arg-1, IDO, iNOS, PD-L1 and Gal-9 was detected using immunohistochemistry (IHC), immunofluorescence, and flow cytometry and Western blotting. The expression of IL-2, TNF-α and IFN-γ were detected by reverse transcription-quantitative polymerase chain reaction (qPCR). Concentrations of IL-10 and TGF-β were measured by enzyme-linked immunosorbent assay (ELISA). Network pharmacology and molecular docking were utilized to screen for potential therapeutic targets and intervening signaling pathways of SSG in lung adenocarcinoma (LUAD). The predictions derived from this approach were further verified using Western blotting.

Results: In vivo experiments using LLC xenograft mice demonstrated that SSG suppressed tumor growth in a dose-dependent manner, with high-dose SSG showing optimal efficacy in inhibiting tumor angiogenesis and cell proliferation. SSG enhances anti-tumor immunity by reducing T cell exhaustion and MDSC-mediated immunosuppression, with SSG + anti-PD-1 combination therapy synergistically optimizing the tumor immune microenvironment. Network pharmacology analysis revealed 5 hub targets (IL2, STAT3, HSP90AA1, LGALS3, and FGF2) associated with immune, LUAD, and active ingredients of SSG, with significant enrichment in the PI3K-Akt pathway. Compared with the control group, the protein expression levels of p-PI3K and p-Akt in the SSG group were significantly down-regulated, indicating that the PI3K-Akt pathway may be inhibited.

Conclusions: SSG could dose-dependently inhibit LLC tumor growth in mice and exert antitumor effects by alleviating T-cell exhaustion and MDSC-mediated immunosuppression. Notably, IL2, STAT3, HSP90AA1, LGALS3 and FGF2, as potential targets of SSG, were significantly enriched in the PI3K-Akt pathway, which provide a novel perspective for the treatment of LUAD.