Atractylodin and β-eudesmol from Atractylodes lancea (Thunb.) DC. Inhibit Cholangiocarcinoma Cell Proliferation by Downregulating the Notch Signaling Pathway

OBJECTIVE: Notch signaling pathway has been reported to be involved in the development and progression of various types of cancer, including cholangiocarcinoma (CCA). Compounds that modulate this signaling pathway could be promising candidates for CCA treatment and control. The study investigated the antiproliferative activities and modulatory effects of atractylodin and β-eudesmol, the two bioactive compounds of Atractylodes lancea (Thunb.) DC. , on Notch signaling and upstream molecules (Notch1 and Notch2 receptors, JAG1, mTOR, PI3K, and YAP), and downstream molecules (Snail) in HuCCT-1 (CCA cell line) and OUMS-36T-1 (normal fibroblast cell line). Gemcitabine (standard drug for CCA), and Notch inhibitors (DAPT and zebularine) were included in the experiments as positive control compounds. METHODS: The antiproliferative activity was evaluated using MTT assay. mRNA and protein expression of Notch signaling molecules were evaluated using real-time PCR and Western blot analysis. RESULTS: Atractylodin and β-eudesmol moderately inhibited HuCCT-1 cell growth with IC(50) (concentration that inhibits cell growth by 50%) of 29.00 ± 6.44 and 16.80 ± 4.41 µg/ml (mean±SD), respectively. The direction and extent of the modulatory effects on mRNA and protein expression in the CCA cell line varied with the signaling molecules. Notch1 receptor was shown to be the most promising target of atractylodin and β-eudesmol in CCA. The level of gene expression was significantly downregulated (0.042 to 0.195 fold of control) after treating HuCC-T1 cells with both compounds at low and high concentrations. The extent and change in Notch1 gene expression correlated well with protein expression. CONCLUSION: The notch signaling pathway could be a promising target of atractylodin and β-eudesmol in CCA.