Sophoridine suppresses macrophage-mediated immunosuppression through TLR4/IRF3 pathway and subsequently upregulates CD8+ T cytotoxic function against gastric cancer.

Gastric cancer is one of the most common and deadly neoplasms with limited effective treatments. The emergence of the immunotherapy has brought great expectations for cancer patients. Sophoridine is extracted from the seeds of sophora alopecuroides and has various pharmacological actions including anti-tumor, anti-inflammatory, anti- arrhythmia and anti-virus. However, the effect of Sophoridine on gastric cancer microenvironment immunity and its underling mechanism remains poorly known. This study was aimed to investigate the effect of Sophoridine on the polarization status of gastric tumor-associated macrophages (TAMs) and its underlying mechanism. We isolated primary bone marrow-derived macrophages (BMDMs) and primary CD8+ T cells to perform coculture assay. Sophoridine educated TAMs polarize to M1-TAMs and suppressed M2-TAMs polarization through TLR4/IRF3 axis. Sophoridine-treated TAMs exhibited stronger pro-inflammatory function through upregulation the expression of INOS, IFN-β and IL-12α, and downregulation the expression of Arg-1, CD206 and IL-10. Sophoridine -primed TAMs increased the proliferation and cytotoxic function of CD8+ T by upregulating the expression of Granzyme-B, TNF-α and Perforin, and downregulated the expression of CD8+ T cells function exhaustion markers PD-1, Tim-3 and Lag-3. Furthermore, Sophoridine inhibited the migration ability of macrophage by decrease the CCR2 expression. Thus, Sophoridine acted on macrophages and CD8+ T cells to reshape gastric cancer immune microenvironment. Our studies provided preclinical basis for clinical application of Sophoridine.