Objective To construct Ginseng polysaccharide-chitosan oligosaccharide nanoparticles (GP-NPs) and investigate whether their combination with radiotherapy could promote the differentiation of natural killer (NK) cells into highly cytotoxic subsets by activating interferon-I (IFN-I)-mediated Janus kinase 3 (JAK3)/signal transducer and activator of transcription 5 (STAT5) signaling pathway, thereby enhancing the antitumor immune response against non-small cell lung cancer (NSCLC). Methods GP-NPs were prepared via the ionic cross-linking method, and their particle size, dispersibility and stability were characterized. A subcutaneous xenograft model of A549 lung cancer cells in nude mice was established, and the mice were divided into PBS group, radiotherapy alone group and GP-NPs combined with radiotherapy group. The antitumor efficacy and mechanism of GP-NPs combined with radiotherapy were comprehensively evaluated by measuring tumor volume, detecting levels of cytokines in serum via ELISA, analyzing NK cells subsets by flow cytometry, detecting the protein expressions of JAK3/STAT5 pathway through Western blotting and performing histopathological analysis. Results GP-NPs combined with radiotherapy significantly inhibited tumor growth, and the effect was significantly better than that of the simple radiotherapy group (P < 0.01). The levels of interferon-γ (IFN-γ), interleukin-15 (IL-15), granzyme and perforin in serum of combined treatment group were significantly increased (P < 0.01). Flow cytometry showed an increase in the proportion of NK cells infiltration within the tumor (P < 0.01), and a significant increase in the proportion of mature cytotoxic subgroups (CD27^-CD11b⁺) (P < 0.01). Western blotting results showed that the combination therapy significantly activated the JAK3/STAT5 signaling pathway (P < 0.01). Organizational analysis showed that the combination therapy group had increased tumor cell apoptosis, aggravated DNA damage and enhanced NK cell infiltration, with no significant toxicity observed in major organs. Conclusion GP-NPs combined with radiotherapy promote the differentiation of NK cells into highly cytotoxic subsets and enhance their antitumor function by activating IFN-I-mediated JAK3/STAT5 signaling pathway. This combination strategy not only significantly improves the efficacy of radiotherapy but also has good biosafety, providing new experimental evidence and strategic directions for the immunocombination therapy of NSCLC.

Ginseng polysaccharide  /  chitosan oligosaccharide  /  nanoparticles  /  immunomodulation  /  NK cells  /  radiotherapy  /  JAK3/STAT5 signaling pathway