High-performance SOD mimetic enzyme Au@Ce for arresting cell cycle and proliferation of acute myeloid leukemia.

SOD-like activity of CeO2 nanoparticles (Ce NPs) is driven by Ce3+/Ce4+, high oxidative stress can oxidize Ce3+ to reduce the ratio of Ce3+/Ce4+, inactivating the SOD activity of Ce NPs. Herein, we found Au@Ce NPs, assembled by Au NPs and Ce NPs, exhibited high-performance of SOD mimetic enzyme activity even upon the oxidation of H2O2. Ce NPs supported by nano-Au can acquire the electrons from Au NPs through the enhanced localized surface plasmon resonance (LSPR), maintaining the stability of Ce3+/Ce4+ and SOD-like activity. Meanwhile, Au@Ce NPs retained the peroxidase function and catalase function. As a result, Au@Ce NPs effectively scavenged O2•- and the derived ROS in AML cells, which are the important signaling source that drives AML cell proliferation and accelerates cell cycle progression. When HL-60 cells were treated by Au@Ce NPs, the removal of endogenous ROS signal significantly arrested cell cycle at G1 phase and suppressed the cell proliferation by blocking the mitogen-activated protein kinases (MAPKs) signaling and the Akt/Cyclin D1 cell cycle signaling. Importantly, this treatment strategy showed therapeutic effect for subcutaneous transplantation of AML model as well as a satisfactory result in diminishing the leukocyte infiltration of liver and spleen particularly. Thus, assembled Au@Ce NPs show the high-performance SOD-like activity, promising the potential in treating AML and regulating abnormal ROS in other diseases safely and efficiently.