Farrerol suppresses epithelial-mesenchymal transition in hepatocellular carcinoma via suppression of TGF-β1/Smad2/3 signaling.

Background: Epithelial-mesenchymal transition (EMT) is an essential process for the metastasis of multiple malignancies, including hepatocellular carcinoma (HCC). Farrerol is a plant-derived flavonoid and has significant pharmacological effects. However, the anticancer activities of farrerol have not been fully elucidated. Here, we investigated the effects of farrerol on HCC progression.

Methods: The potential of farrerol to prevent HCC cell migration and invasiveness was evaluated by wound healing and transwll matrix assays. Immunoblotting, immunofluorescence, and qPCR were used to detect the levels of EMT-related proteins. Transforming growth factor beta (TGF-β) (10 ng/ml) was used to stimulate HCC cells, followed by measurement of cell migration, invasiveness, and the EMT. TGF-β1/Smads signaling was examined by immunoblotting. A xenograft mouse model was used to assess the anticancer efficacy of farrerol in vivo. The expression levels of EMT- and angiogenesis-related proteins in xenograft tumors were evaluated by immunoblotting or immunohistochemistry.

Results: We found that farrerol blocked HCC cell migration and invasiveness. Farrerol upregulated E-cadherin levels and reduced N-cadherin and vimentin levels. Farrerol also downreuglated the expression levels of EMT-related transcription factors including slug, snail, twist, and zeb1. Furthermore, farrerol suppressed TGF-β-stimulated migration, invasiveness, and the EMT in HCC cells. The phosphorylation of Smad 2/3 induced by TGF-β was inhibited by farrerol. Importantly, farrerol suppressed HCC growth and the EMT in vivo. Farrerol also inhibited tumor angiogenesis by inhibiting hypoxia-inducible factor-1 alpha (HIF-1α) and vascular endothelial growth factor (VEGF) in vivo.

Conclusion: Overall, farrerol suppresss HCC by inhibiting migration, invasiveness, the EMT, and angiogenesis, implying that farrerol could be a promising antimetastasis agent for HCC.