A Supramolecular Self-Assembled Nanoprodrug for Enhanced Ferroptosis Therapy.

Ferroptosis can induce cell death that leverages Fe²⁺-triggered Fenton reactions within living organisms, leading to an excessive accumulation of lipid peroxides (LPOs) and inducing cell death. Ferroptosis can effectively circumvent the inevitable drug resistance encountered with traditional apoptotic therapies. However, several issues remain in the clinical application of ferroptosis anticancer therapy, primarily due to the poor efficiency of intracellular Fenton reaction. To address this issue, we developed a supramolecular self-assembled codelivery nanoprodrug (DOX@C18Fc-Q[7] NPs) composed of ferrocene (Fc)-based supramolecular amphiphiles (C18Fc-Q[7]) and a nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) activator (doxorubicin, DOX). The C18Fc-Q[7] is based on Fc linked to a hydrophobic long-chain alkane via a disulfide linkage, which interacts with hydrophilic Q[7] to form self-assembled amphiphiles. Importantly, the host-guest interaction between Q[7] and Fc effectively enhances the solubility of Fc while maintaining the stability of the Fe²⁺ source. Moreover, C18Fc-Q[7] also acts as a good carrier for loading DOX due to its good self-assembly. In cancer cells, elevated glutathione (GSH) triggers the disassembly of nanoprodrug, leading to the release of DOX, which upregulates NOX4 expression and increases H₂O₂ level, thereby promoting an efficient Fenton reaction for Fc-induced ferroptosis. Moreover, DOX induces cell death through apoptosis, providing a synergistic effect to further enhance the ferroptosis therapy. In vivo studies have demonstrated that this enhanced ferroptosis therapy effectively inhibits tumor growth and metastasis while maintaining good biosafety.