GSH/pH Dual Activatable Cross‐linked and Fluorinated PEI for Cancer Gene Therapy Through Endogenous Iron De‐Hijacking and in Situ ROS Amplification

Ferroptosis‐related cancer therapy is limited by insufficient Fe2+/Fe3+ redox pair and hydrogen peroxide (H2O2) for producing lethal hydroxyl radicals (·OH). Although exogenous iron or ROS‐producing drugs can enhance ferroptosis, exploiting endogenous iron (labile iron pool, LIP) stored in ferritin and promoting ROS generation may be safer. Herein, a metal/drug‐free nanomedicine is developed for responsive LIP release and H2O2 generation on the mitochondria membranes, amplifying hydroxyl radical production to enhance ferroptosis‐mediated antitumor effects. A glutathione(GSH)/pH dual activatable fluorinated and cross‐linked polyethyleneimine (PEI) with dialdehyde polyethylene glycol layer nanocomplex loaded with MTS‐KR‐SOD (Mitochondria‐targeting‐sequence‐KillerRed‐Superoxide Dismutase) and CRISPR/Cas9‐CA IX (Carbonic anhydrase IX (CA IX)) plasmids (FP@MC) are developed for enhanced ferroptosis through endogenous iron de‐hijacking and in situ ROS amplification. Two plasmids are constructed to knockdown CA IX and translate KillerRed‐SOD recombinant protein specifically on mitochondria membranes, respectively. The CA IX knockdown acidifies the intracellular environment, leading the release of LIP from ferritin as a “flare” to initiate endogenous chemodynamic therapy. Meanwhile, MTS‐KR‐SOD generates H2O2 when irradiated by a 590 nm laser to assist chemodynamic therapy, leading to ROS amplification for mitochondria damage and lipid peroxide accumulation. The combined therapeutic effects aggravate cancer ferroptosis and suppress tumor growth, providing a new paradigm for amplifying ROS and iron ions to promote ferroptosis‐related cancer therapy. The GSH/pH dual activatable fluorinated PEI system is used to transfect MTS‐KR‐SOD and Cas‐CA IX plasmids into B16‐F10 cancer cells in vitr and in vivo. Decreased intracellular pH caused by the knockdown of CA IX de‐hijacked Fe2+ from ferritin, ignited H2O2 fuel triggered by laser irradiated MTS‐KillerRed‐SOD for enhanced ferroptosis. Thus, achieving cascade‐amplify ROS cytotoxicity by photodynamic‐assisted endogenous chemodynamic therapy.