Codelivery of apigenin, FdUMP and CD276 antibody synergistic inhibit colorectal cancer by ferroptosis-apoptosis-pyroptosis and CD276 blockade.

Mitochondria provides adenosine triphosphate for multiple vital movements to ensure tumor cell proliferation. Compared to the broadly used method of inducing DNA replication arrest to kill cancer, inducing mitochondria damage to cause energy shortage is quite promising as it can inhibit tumor cell bioactivities, increase intracellular accumulation of toxic drugs, eventually sensitize chemotherapy and even reverse drug resistance. Breaking the balance of glutathione (GSH) and reactive oxygen species (ROS) contents have been proven efficient in destroying mitochondria respectively. Herein, apigenin, a GSH efflux reagent, and 2'-deoxy-5-fluorouridine 5'-monophosphate sodium salt (FdUMP) that could induce toxic ROS were co-delivered by constructed lipid nanoparticles, noted as Lip@AF. An immune-checkpoint inhibition reagent CD276 antibody was modified onto the surface of Lip@AF with high reaction specificity (noted as αCD276-Lip@AF) to enhance the recognition of immune cells to tumor. Results showed that the redox balance was destroyed, leading to severe injury to mitochondria and cell membrane. Furthermore, synergistic DNA/RNA replication inhibition caused by inhibiting the function of thymidylate synthase were observed. Eventually, significantly enhanced cytotoxicity was achieved by combining multiple mechanisms including ferroptosis, apoptosis and pyroptosis.