Sophora tonkinensis reprograms tumor-associated macrophages to M1-like phenotype and exerts anti-hepatocellular carcinoma effects.

[ETHNOPHARMACOLOGICAL RELEVANCE] Sophora tonkinensis radix et rhizoma is a medicinal herb traditionally used to treat inflammatory diseases and various types of cancer, previous phytochemistry studies have identified abundant alkaloids and flavonoids as the major bioactive components with anti-inflammatory, anti-tumor, hepatoprotective and immunomodulatory pharmacological effects, but their effects on Tumor-associated macrophages (TAMs) and the tumor immune microenvironment have not been systematically explored.

[AIM OF THE STUDY] This work aimed to establish whether a standardized extract of Sophora tonkinensis (STE) can halt IL-4-driven M2 macrophage polarization, reprogram established M2-like tumor-associated macrophages toward a pro-inflammatory M1-like phenotype, and clarify the underlying molecular mechanisms and in vivo efficacy of these immunomodulatory actions.

[MATERIALS AND METHODS] Bone-marrow-derived macrophages (BMDMs) were polarized to an M2 phenotype and subsequently treated with STE. Expression of the M1/M2 markers Arg-1, CD206, iNOS, and CD86 in these macrophages was quantified by immunoblotting, qPCR, and flow cytometry. The impact of STE-pretreated M2-conditioned medium on the proliferation, migration, and invasion of Hepa 1-6 cells was then examined. H22 cells were subcutaneously inoculated into Balb/c mice to assess STE's effects on the macrophage landscape within the tumor immune microenvironment and to evaluate its antitumor efficacy.

[RESULTS] STE dose-dependently suppressed IL-4-induced Arg-1 and CD206 while up-regulating iNOS and CD86, indicating a blockade of M2 polarization and a shift toward an M1 signature. Mechanistically, STE markedly increased JAK1 and STAT1 phosphorylation. Functionally, it potently inhibited invasion and migration of Hepa 1-6 cells. In tumor-bearing mice, robust suppression of tumor growth was accompanied by a pronounced reduction in M2-like TAMs and a reciprocal increase in M1-like macrophages within the tumor microenvironment.

[CONCLUSION] STE reprograms TAMs via the JAK1/STAT1 axis and exhibits robust antitumor activity, underscoring its promise as a natural, macrophage-targeted immunotherapeutic that warrants further investigation for integration into cancer treatment strategies.