Nano-carriers mediate reciprocally chained promotion between ROS and mitochondrial calcium overload for enhanced antitumor therapy.

Calcium ions (Ca²⁺) and reactive oxygen species (ROS) play pivotal roles in cellular signaling and the regulation of diverse biological processes. Complex and dynamic interactions between Ca²⁺ and ROS signaling pathways are often exploited by tumor cells to resist therapeutic interventions. In this study, we present a strategy of cancer treatment based on the reciprocally reinforcing interplay between ROS burst and mitochondrial calcium overload. The major components of our nano carriers integrate CaCO₃ nanoparticles loaded with glucose oxidase (GOx), and copper peroxide nanodots (CPDs) in a DSPE-S-S-PEG-modified liposomal format (abbr. GCCL,). This hybrid nanosystem is designed to facilitate controlled and accelerated release of Ca²⁺ and ROS, thereby establishing dual positive feedback loops that amplify both mitochondrial calcium accumulation and oxidative stress. By harnessing this synergistic cycle, our platform enhances the efficacy of chemodynamic therapy and calcium-induced mitochondrial damage, offering a promising strategy for translational cancer treatment. STATEMENT OF SIGNIFICANCE: Here we report a strategy of antitumor therapeutic by designing a dual positive feedback loop of pH-driven self-accelerated Ca²⁺ and H₂O₂ release, thus reciprocally promoting ROS production and mitochondrial calcium overload for tumor eradication. After cellular uptake of GCCL, releasing of the cargos inside the liposomes can introduce a cascade of chemical reactions and biochemical cues, leading to calcium overload and ROS burst. These two major effects are mutually linked with each other, which is utilized by our GCCL design to fuel the positive feedback loops for tumor cell apoptosis in vitro and effective cancer ablation in vivo. Our nano therapy stands out with improved tumor suppression, with a lower dosage of copper element in the treatments of 4T1 xenograft tumor-bearing BALB/c mice model.