Abstract
Cholangiocarcinoma (CCA) is an aggressive cancer of the bile duct epithelium. Anthocyanins are water-soluble flavonoids that contribute to the color of fruits and pigmented rice. Black rice bran is rich in anthocyanin pigments and exhibits certain health benefits, including anticancer activity; however, the effect of black rice bran-derived anthocyanins (BBR-M-10) on CCA progression remains unclear. The present study assessed the cytotoxic effects of BBR-M-10 using a Sulforhodamine B assay. The metastatic properties of BBR-M-10 on CCA cell lines were investigated using wound healing, Transwell in vitro migration and invasion assays. The underlying mechanisms of BBR-M-10 bioactivity were examined by quantitative PCR and western blotting. Glycosylation changes were determined by lectin cytochemistry and flow cytometry. The present study demonstrated that BBR-M-10 was not toxic to CCA cell lines, but BBR-M-10 attenuated CCA cell migration and invasion, as evidenced by the increased expression levels of epithelial markers (F-actin and claudin-1), decreased expression levels of mesenchymal markers (vimentin) and a decrease in the activation and phosphorylation of AKT in BBR-M-10-treated CCA cell lines. In addition, aberrant glycosylation was observed in BBR-M-10-treated CCA cell lines, as evidenced by the low expression level of surface Sambucus Nigra lectin-binding α2,6-sialylated glycans and the reduction of α2,6 sialyltransferase gene expression levels after BBR-M-10 treatment in CCA cell lines. These findings suggested that black rice bran-derived anthocyanins could potentially be used as anti-metastatic agents against CCA.