Paeoniflorin Affects Hepatocellular Carcinoma Progression by Inhibiting Wnt/β-Catenin Pathway through Downregulation of 5-HT1D

Background: Hepatocellular Carcinoma (HCC) is a primary liver cancer with high mortality. Paeoniflorin is a pinane monoterpene picroside with anti-tumor effect isolated from Chinese peony root and white peony root. Objective: The study was conducted to investigate the underlying mechanism of Paeoniflorin (PF) regulating Hepatocellular Carcinoma (HCC) progression via 5-hydroxytryptamine receptor 1D (5-HT1D). Methods: HepG2 and SMMC-7721 hepatoma cells were treated with different concentrations of PF (0, 5, 10, 20 μM). Cell proliferation, apoptosis, migration, and invasion were examined by CCK-8 and colony formation assays, flow cytometry, wound healing assay, and transwell assay, respectively. RTqPCR assay was used to detect the expression level of 5-HT1D, and Western blot assay was used to detect the expressions of 5-HT1D and Wnt/β-catenin pathway-related proteins. Results: With the increase in PF concentration, the mRNA levels of 5-HT1D in HepG2 and SMMC- 7721 hepatoma cells were decreased in a dose-dependent manner, and the proliferation, colony formation, migration and invasion ability of cells were gradually weakened, while the apoptosis rate was gradually increased. Overexpression of 5-HT1D significantly promoted the proliferation, colony formation, migration and invasion of HepG2 and SMMC-7721 cells, and increased the expression of Wnt/β-catenin pathway-related proteins, β -actenin, survivin, C-myc, and Cyclin D1. Furthermore, 5-HT1D overexpression could reverse the effect of PF on hepatoma cells and inhibit the expressions of Wnt/β-catenin pathway-related proteins. Conclusion: PF may inhibit the progression of HCC by blocking Wnt/β-catenin pathway expression through downregulating 5-HT1D.