Bufalin induces ferroptosis by modulating the 2,4-dienoyl-CoA reductase (DECR1)-SLC7A11 axis in breast cancer.

Breast cancer (BC) is a leading cause of cancer-related mortality worldwide. 2,4-dienoyl-CoA reductase (DECR1), an auxiliary component of beta-oxidation, has been recognized for its role in enhancing lipid peroxidation and inducing ferroptosis in prostate cancer. However, its involvement in breast cancer remains largely unexplored. Our study revealed a notably elevated expression of DECR1 in breast cancer tissues, which correlated with increased malignant characteristics. Importantly, the overexpression of DECR1 significantly enhanced proliferation and migration capabilities in MDA-MB-231 cells. Through a comprehensive high-content screening approach, we identified bufalin and its derivative as potent inhibitors of DECR1 expression. Notably, bufalin demonstrated the highest binding energy during molecular docking studies and was found to promote the degradation of DECR1 via autophagy and ubiquitination. Furthermore, bufalin induced ferroptosis in MDA-MB-231 cells by modulating levels of malondialdehyde (MDA), triglycerides (TG), reactive oxygen species (ROS) and Fe while downregulating the expression of hormone-sensitive lipase (HSL), ferritin heavy chain protein 1 (FPN), solute carrier family 7 member 11 (SLC7A11), and glutathione peroxidase 4 (GPX4). These effects were counteracted by DECR1 overexpression. In vivo experiments demonstrated that bufalin inhibited the tumor growth, while decreasing the expression levels of HSL, FPN, SLC7A11, and GPX4, alongside increasing levels of 4-hydroxynonenal (4-HNE). Crucially, the ferroptosis effects induced by bufalin in vivo were also reversed by DECR1 overexpression. Subsequently, we discovered that SLC7A11 interacts with DECR1, inhibition of SLC7A11 led to decreased expression levels of DECR1 along with an accumulation of MDA and Fe, effects that were similarly reversed by DECR1 overexpression. Collectively, our findings suggest that targeted therapy against DECR1 combined with further inhibition of its downstream pathway involving SLC7A11/GPX4 may represent a promising strategy for treating breast cancer.