Emodin Induces Oxidative Stress and Ferroptosis in Hepatocellular Carcinoma Cells via Inactivating miR- 4465/NFE2L3/HMGCR/GPX4 Signaling Axis

Ferroptosis is a form of programmed cell death characterized by iron-dependent lipid peroxidation. Targeting ferroptosis is considered a novel strategy for cancer treatment. The benefits of using natural products to treat tumors have drawn more attention. Emodin, a natural anthraquinone derivative, has been shown to exert anti-tumor effects by promoting the generation and accumulation of reactive oxygen species (ROS), inducing apoptosis, autophagy, and cell cycle arrest. The molecular processes behind Emodin-mediated ferroptosis in hepatocellular carcinoma (HCC) cells were examined in our work. Emodin caused ferroptosis and suppressed growth in HCC cells in vitro. Emodin could increase ROS and lipid peroxidation, meanwhile decreasing glutathione (GSH), mitochondrial membrane potential, glutathione peroxidase 4 (GPX4), and 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) expression, these effects could be reversed by Ferostatin-1 (Fer-1, an inhibitor of ferroptosis) and NFE2-like bZIP transcription factor 3 (NFE2L3). Mechanistically, Emodin enhances the expression of miR-4465 , thereby suppressing NFE2L3 expression. The interaction between NFE2L3 and the HMGCR promoter is diminished, which subsequently downregulates GPX4 expression via the mevalonate pathway, leading to ferroptosis. Overexpression of NFE2L3 could alleviate Emodin-induced ferroptosis in HCC cells. Moreover, NFE2L3 knockout markedly reduced the expression of HMGCR and GPX4 in the Nfe2l3 ^−/− mouse model. Emodin also caused ferroptosis and inhibited tumor development in a xenograft mice model. In conclusion, these results suggested that Emodin induces ferroptosis by inactivating the NFE2L3/HMGCR/GPX4 pathway in HCC cells. Emodin may be a promising candidate for the development of anticancer drugs and offers new strategies for cancer therapy.