Unsaturated fatty acid-doped liposomes deliver piperine to deactivate defensive mechanism for ferroptosis in cancer therapy

Glutathione peroxidase 4 (GPX4) and dihydroorotate dehydrogenase (DHODH) are two mitochondrial cellular defense systems that operate in parallel to protect against ferroptosis. Simultaneously deactivating both proteins can initiate lipid peroxidation, leading to ferroptosis and subsequent cell death. In this study, we developed a transferrin-modified liposomes (TDPL) doped with unsaturated fatty acid docosahexaenoic acid (DHA) as a lipid peroxidation inducer and encapsulated piperine (PIP) to realize effective anticancer therapy. Specifically, transferrin serves a dual role in this system, acting as both a ligand targeting transferrin receptors and a Fe 3+ ionophore. Triggered by the low pH in the lysosome, Fe 3+ ions bound to transferrin are released and reduce to Fe 2+ , which can subsequently catalyze the peroxidation of unsaturated fatty acid. Meanwhile, DHA incorporated into the lipid bilayer of the liposome, can fuse with the cell membrane and deactivate GPX4 and thus inducing lipid peroxidation. Furthermore, PIP functions as a potent DHODH inhibitor. Such combination prevents the detoxification of lipid hydroperoxides by GPX4 and the suppression of lipid peroxyl radical production by DHODH. Collectively, this straightforward system promotes antitumor efficacy of unsaturated fatty acid DHA and drug molecule PIP by inhibiting ferroptosis protection mechanisms to induce lipid peroxidation.