Capillarisenol C, a novel bisphenol from Artemisia capillaris, induces autophagic death in hepatocellular carcinoma through endoplasmic reticulum stress

Abstract

In our previous work, we isolated a novel bisphenol named capillarisenol C (Cap C) from Artemisia capillaris. Preliminary studies indicated potential anti-hepatocellular carcinoma (HCC) activity. However, its mechanism remains unclear. In this study, we aimed to investigate the function and molecular mechanism of the anti-HCC activity of Cap C. First, We evaluated the inhibitory effect of Cap C on the viability of HepG2 and Huh7 cells using CCK8 assays. The results showed that Cap C sharply reduced the viability of HepG2 and Huh7 cells in a time- and concentration-dependent manner, however, lenvatinib (clinical drugs for the treatment of HCC) had no obvious growth inhibitory effect on HepG2 and Huh7 cells at the corresponding concentration. By calculation, the half maximal inhibitory concentrations (IC50) of Cap C were 8.58 and 4.96 µM for for HepG2 and Huh7 cells at 48 h. Then, we investigated its autophagic effects on liver cancer cells using immunofluorescence staining and CRISPR/Cas9 assays. To study the mechanism of Cap C, we used quantitative PCR and western blotting. We found that Cap C effectively inhibited the proliferation of HepG2 cells and increased MAP1LC3-II expression. Moreover, Cap C–induced cell death was attenuated by autophagy-related gene ATG7 knockdown. Mechanistic studies showed that Cap C significantly promoted the expression of endoplasmic reticulum (ER) stress–related proteins. Our results suggest that Cap C may lead to autophagic HCC cell death by inducing ER stress.