Enhancing the Effect of Pharmacological Ascorbate in Cancer Therapy via Acid-Triggered Ferritin Nanoparticles

The application of ascorbate (vitamin C) for cancer therapy was first proposed in the 1970s and has shown promising results in recent clinical trials. Pharmacological doses of ascorbate selectively induce cell death in different types of cancer cells through the generation of H₂ O_2. However, some cancer cells are resistant to ascorbate. So increasing the sensitivity of resistant cancer cells to ascorbate has attracted considerable attention. Till now, a few attempts in nanomaterials have been made to improve the effect of ascorbate. In this study, a simple ferritin caged copper nanoparticle (Fn-Cu) significantly improves the susceptibility of ascorbate-resistant cancer cells to pharmacological ascorbate via selective inhibition of catalase activity in cancer cells, while having negligible cytotoxicity to normal cells. Remarkably, combination of Fn-Cu with a lower dose of ascorbate significantly inhibits ascorbate-resistant tumor growth and metastasis in vivo. These data demonstrate Fn-Cu has the therapeutic potential by enhancing the effect of ascorbate in cancer therapy.