Photo-enhanced catalytic activity enabled by core–shell nanozymes for combination breast cancer therapy

Enhanced catalytic therapy of triple-negative 4T1 breast tumors through the application of photo-enhanced peroxidase (POD)-like and catalase (CAT)-like activities combined with chemotherapy could be enabled by core-shell nanozymes. Therefore, the dual POD and CAT-like activities of the core-shell iron oxide (Fe3O4)-@gold (IO@Au) nanozymes loaded with epirubicin (EPI) were evaluated in this study for photoenhanced combination therapy. The core-shell nanozymes induced oxidative stress and apoptosis, and these effects were enhanced upon application of PDT, as demonstrated by ROS and caspase-3 activity assays. Additionally, it was shown that by reducing the expression of HIF-1α and upregulation of caspase-3 mRNA, core-shell nanozymes with and without PDT were able to induce a significant reduction in tumor weight, when compared to free EPI. The bio-distribution of the drug-loaded into core-shell nanozymes showed a higher accumulation of the EPI in the 4T1 breast tumor when compared to samples treated with free EPI. Overall core-shell nanozymes with catalytic-like activity can be used as potential platforms for photoenhanced combination therapy.