Precise Chemodynamic Therapy of Cancer by Trifunctional Bacterium-Based Nanozymes

Chemodynamic
therapy (CDT) destroys cancer cells by converting
H2O2 or O2 into reactive oxygen species
(ROS), but its therapeutic efficacy is restricted by the antioxidant
capacity of tumor. Previous solutions focused on strengthening the
nanodrugs with the ability to increase ROS production or weaken the
antioxidant capacity of cancer cells. Conversely, we here develop
a mild nanodrug with negligible side effects. Specifically, the Au@Pt
nanozyme decorated on a bacterial surface (Bac-Au@Pt) is reported
to achieve precise CDT. Due to the tumor targeting ability of bacteria
and catalytic property of Au@Pt nanozyme under acidic conditions,
this nanosystem can release ROS to tumor cells effectively. In addition,
the interferon gamma released by T cells specifically decreases the
intracellular reductants in tumor cells, while having no obvious effect
on normal cells. Therefore, a low dose of Bac-Au@Pt achieves a satisfactory
therapeutic efficacy to tumor cells and is nontoxic to normal cells
even at their acidic components. This nanosystem enables CDT and immunotherapy
to mutually benefit and improve by each other, providing a promising
strategy to achieve high anticancer efficacy even with a low dose
usage.