Exploring the immunomodulatory mechanisms of Shiyiwei Shenqi tablets in NSCLC: N-acetylaspartate as a biomarker for modulating M1/M2 macrophage balance.

Background: Macrophages, with their dual role in immune regulation and metabolic characteristics, are emerging as the pivotal target in tumor treatments. Shiyiwei Shenqi tablets (SST) is widely used for its immunomodulatory effects in non-small cell lung cancer (NSCLC). However, its mechanism remains unclear.

Purpose: This study sought to investigate whether SST regulates immunity in NSCLC through macrophages and to elucidate its underlying mechanisms.

Methods: The immunomodulatory mechanisms were initially predicted using the random walk with restart (RWR) algorithm and subsequently verified using the Lewis lung carcinoma model and macrophage cell depletion experiment. The regulatory effects of SST on macrophage phenotype and function were testified through flow cytometry, Western blot, qRT-PCR, ELISA, wound healing, migration, and tube formation assays. Furthermore, non-targeted and targeted metabolomics, combined with molecular studies, were employed to investigate the immunometabolic mechanisms in macrophages.

Results: SST treatment markedly impeded tumor progression and identified macrophages as the target cells for enhancing CD8⁺ T cell immunity against tumors. Specifically, SST reprogrammed macrophages by polarizing towards an M1-like phenotype while inhibiting the M2-like phenotype, reducing M2-driven angiogenesis and metastasis. Mechanistically, SST inhibited glutamine (Gln) metabolism, with N-acetylaspartate (NAA), a downstream metabolite of Gln, identified as a key regulator across macrophage phenotypes. SST suppressed NAA by downregulating NAT8L and upregulating ASPA, thereby relieving NAA-mediated suppression of NF-κB activation.

Conclusion: SST enhanced anti-tumor immunity in NSCLC by promoting M1 macrophages and suppressing M2 macrophages. NAA, a macrophage-derived biomarker, highlighted SST's role in regulating M1/M2 balance.