ROS-responsive fluorinated polyethyleneimine vector to co-deliver shMTHFD2 and shGPX4 plasmids induces ferroptosis and apoptosis for cancer therapy

Ferroptosis is a newly discovered non-apoptotic cell death form but its therapeutic efficacy triggered by traditional iron-based nanomaterials or classic drug inducers has been far from satisfactory due to the high glutathione (GSH) level in cancer cells and insufficient lipid peroxide production. Here we reported a ferroptosis/apoptosis combinational therapy by depleting GSH and downregulating GPX4 to disrupt redox homeostasis and amplify ferroptosis-related oxidation effect. In this study, we developed reactive oxygen species (ROS)-responsive serum-resistant nanoparticles with thioketal-crosslinked fluorinated polyethyleneimine 1.8K (TKPF) as the core, which were wrapped with hyaluronic acid (HA) as the shell (TKPFH NP) to co-deliver shGPX4 and shMTHFD2 plasmids for cancer treatment. The highly efficient and tumor-selective gene carrier TKPFH NPs revealed outstanding transfection efficiency (∼100 %) and sustained the efficiency (∼50 %) even in media containing 90 % FBS. Mediated by HA, TKPFH NPs actively targeted CD44 receptors, thus enabling efficient uptake by tumor cells and experiencing surface charge conversion to induce subsequent lysosomal escape. Then the TKPF NPs were effectively disintegrated by the abundant ROS in cancer cells, which facilitated the release of plasmids and avoided the cytotoxicity of cationic polymers. shGPX4 plasmid induced ferroptosis by producing ROS and lipid peroxides via downregulating GPX4, while shMTHFD2 triggered apoptosis by modulating NADPH/NADP and depleting GSH of the cancer cells. Moreover, GSH consumption caused by shMTHFD2 indirectly suppressed GPX4 and further augmented ferroptosis, showing synergistic anticancer effect against B16-F10 cells. Taken together, the rationally designed dual-gene loaded TKPFH NPs provided a safe and high-performance platform for enhanced ferroptosis-apoptosis combined anticancer efficacy based on gene therapy.