Targeted degradation of NDUFS1 by agrimol B promotes mitochondrial ROS accumulation and cytotoxic autophagy arrest in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a global public health problem with increased morbidity and mortality. Agrimol B, a natural polyphenol, has been proved to be a potential anticancer drug. Our recent report showed a favorable anticancer effect of agrimol B in HCC, however, the mechanism of action remains unclear. Here, we found agrimol B inhibits the growth and proliferation of HCC cells in vitro as well as in an HCC patient-derived xenograft (PDX) model. Notably, agrimol B drives autophagy initiation and blocks autophagosome-lysosome fusion, resulting in autophagosome accumulation and autophagy arrest in HCC cells. Mechanistically, agrimol B downregulates the protein level of NADH:ubiquinone oxidoreductase core subunit S1 (NDUFS1) through caspase 3-mediated degradation, leading to mitochondrial reactive oxygen species (mROS) accumulation and autophagy arrest. NDUFS1 overexpression partially restores mROS overproduction, autophagosome accumulation, and growth inhibition induced by agrimol B, suggesting a cytotoxic role of agrimol B-induced autophagy arrest in HCC cells. Notably, agrimol B significantly enhances the sensitivity of HCC cells to sorafenib in vitro and in vivo. In conclusion, our study uncovers the anticancer mechanism of agrimol B in HCC involving the regulation of oxidative stress and autophagy, and suggests agrimol B as a potential therapeutic drug for HCC treatment.