Sini decoction inhibits colorectal cancer liver metastasis by suppressing HIF-1α-dependent exosomal integrin signaling.

ETHNOPHARMACOLOGICAL RELEVANCE: Sini Decoction (SND), composed of Aconiti Lateralis Radix Praeparata, Zingiberis Rhizoma, and Glycyrrhizae Radix et Rhizoma, is traditionally used to restore "Yang" and modulate immunity. Clinically, SND is applied as adjuvant therapy in colorectal cancer, yet its anti-metastatic mechanisms remain unclear.

AIM OF THE STUDY: To clarify the bioactive constituents and mechanisms through which SND inhibits colorectal cancer liver metastasis, focusing on tumor-derived exosomes and macrophage polarization.

MATERIALS AND

METHODS

A murine colorectal liver metastasis model was established using luciferase-labeled mouse CT26 cell and treated with SND. Tumor burden, histology, immunohistochemistry, spectral flow cytometry, ELISA, Western blotting, immunofluorescence, and single-cell RNA sequencing were used to evaluate immune remodeling and exosomal signaling. SND-medicated serum, exosome inhibition (GW4869), and integrin αv/β5 knockdown were applied in macrophage co-culture assays. Network pharmacology, molecular docking, and CETSA identified upstream regulators.

RESULTS

SND significantly reduced liver metastases, improved hepatic pathology, and decreased Ki-67 expression. SND reshaped the immune microenvironment by lowering CD206+ M2 macrophages. SND suppressed tumor-derived exosome secretion and weakened exosomal ITGαvβ5-driven M2 polarization. Single-cell analysis confirmed integrin-related activation in macrophages. Network pharmacology and experiments identified HIF-1α as a key regulator of exosomal integrin loading. Aconitine directly bound and reduced HIF-1α, limiting Rab-dependent exosome biogenesis.

CONCLUSION

SND inhibits colorectal cancer liver metastasis by targeting HIF-1α to suppress ITGαvβ5-enriched exosome secretion and block M2 macrophage polarization, supporting its ethnopharmacological utility against metastatic disease.