Norcantharidin attenuates epidermal growth factor-induced proliferation, EMT and motility in ARPE-19 cells by modulating the AKT/snail/E-cadherin axis

Norcantharidin (NCTD) is a demethylated derivative of cantharidin demonstrated to have anti-proliferative, anti-inflammatory, and anti-fibrosis properties. The purpose of the current study is to investigate the underlying mechanisms and signaling pathways affected by NCTD in human ARPE-19 cells.Cell growth and rate of proliferation were assayed by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, colony formation assay, and cell cycle distribution/quantification. Cell motility was detected with in vitro migration assay. The level of epithelial-mesenchymal transition (EMT)-related proteins and mRNA (Snail, Slug, E-cadherin) were detected using Western blotting, real-time quantitative polymerase chain reaction, and immunofluorescence assay. Overexpression of Snail plasmid was determined by transfection assay.We found that NCTD reduced epidermal growth factor (EGF)-induced ARPE-19 cell viability and proliferation through increasing the p21 and p27 expression and decreasing the cyclin D1 expression. NCTD also inhibited EGF-mediated EMT and cell motility through increased protein and mRNA levels of E-cadherin and decreased Snail in EGF-induced ARPE-19 cells. Overexpression of Snail significantly decreased ARPE-19 cell motility and increased E-cadherin expression in NCTD-treated cells. Additionally, when NCTD was combined with a PI3K inhibitor (LY294002) significantly decreased the p-AKT and Snail expression, and increased the E-cadherin expression of EGF treatment in ARPE-19 cells.The current findings revealed that NCTD suppresses the EGF-induced proliferation, motility, and EMT of ARPE-19 cells through inactivation of the AKT-mediated Snail/E-cadherin pathway. NCTD may be a potential preventive agent for proliferative vitreoretinopathy.