Hedyotis diffusa Willd-Scutellaria barbata D.Don Suppresses Colorectal Cancer Liver Metastasis by Targeting hsa_circ_0039933-Mediated Epithelial-Mesenchymal Transition

Colorectal cancer (CRC) liver metastasis remains a major cause of mortality, necessitating novel therapeutic strategies. Hedyotis diffusa Willd -Scutellaria barbata D.Don (HD-SB), a traditional Chinese herbal formulation, has demonstrated anti-tumor potential. However, its mechanism in CRC metastasis, particularly through the regulation of circular RNAs, remains unexplored. A CRC liver metastasis model was established in Balb/c nude mice via intrasplenic injection of HCT-15 cells. Mice received HD-SB treatment. Hematoxylin-eosin staining, Masson staining, and immunohistochemistry (Ki67 and Cytokeratin 19 [CK19]) were carried out to observe pathologic changes in CRC liver metastases. In vitro, HCT-15 cells were treated with tumor necrosis factor-α (TNF-α) to induce metastasis. hsa_circ_0039933 was knocked down and overexpressed in vitro. Transwell, wound healing, EdU, and cell counting kit-8 assays were employed to assess cell invasion, migration and proliferation, respectively. The levels of epithelial-mesenchymal transition (EMT) markers were evaluated by quantitative real-time polymerase chain reaction and western blot. HD-SB treatment dose-dependently reduced hepatic tumor nodules, fibrosis, Ki67 and CK19 expression in vivo, with high-dose HD-SB showing superior efficacy. EMT reverse (upregulated E-cadherin, downregulated N-cadherin/Vimentin) and hsa_circ_0039933 suppression were observed in HD-SB treated CRC mouse. In vitro, HD-SB attenuated TNF-α-induced proliferation, migration, and invasion, synergizing with hsa_circ_0039933 knockdown to suppress EMT and metastatic phenotypes. Conversely, hsa_circ_0039933 overexpression exacerbated TNF-α-driven aggressiveness, which was effectively counteracted by HD-SB. Collectively, HD-SB inhibits CRC liver metastasis by targeting hsa_circ_0039933 and modulating EMT. These findings highlight HD-SB as a promising circRNA-directed therapeutic agent for metastatic CRC.