An ROS-Activatable Nanoassembly Remodulates Tumor Cell Metabolism for Enhanced Ferroptosis Therapy.

Ferroptosis is an emerging antitumor option and has demonstrated unique advantages against many tumor indications. However, its efficacy is potentially hindered by the endogenous lipid peroxide-scavenging mechanisms and the reliance on acidic pH. Herein, a nanointegrated strategy based on clinically-safe components to synergistically remodel glutathione and lactate metabolism in tumor cells for enhanced ferroptosis therapy is developed. First ferrocene is conjugated on PEGylated polyamidoamine dendrimers via reactive oxygen species (ROS)-cleavable thioketal linkage, which would further self-assemble with the glutathione (GSH)-depleting agent diethyl maleate (DEM) and monocarboxylate transporter 4-inhibiting siRNA (siMCT4) to afford biostable nanoassemblies (siMCT4-PAMAM-PEG-TK-Fc@DEM). The nanoassemblies can be activated by the elevated ROS levels in tumor intracellular environment and readily release the incorporated therapeutic contents, afterward DEM can directly conjugate to GSH to disrupt the glutathione peroxidase 4 (GPX4)-mediated antioxidant defense, while siMCT4 can block the MCT4-mediated efflux of lactic acid and acidify the intracellular milieu, both of which can improve the ferrocene-catalyzed lipid peroxidation and induce pronounced ferroptotic damage. The siMCT4-PAMAM-PEG-TK-Fc@DEM nanoplatform demonstrates high ferroptosis-based antitumor potency and good biocompatibility in vitro and in vivo, which may offer new avenues for the development of more advanced antitumor therapeutics with improved translatability.