Amplification of oxidative stress with a hyperthermia-enhanced chemodynamic process and MTH1 inhibition for sequential tumor nanocatalytic therapy

During chemodynamic therapy (CDT), tumor cells can adapt to hydroxyl radical (OH) invasion by activating DNA damage repairing mechanisms such as initiating mutt homologue 1 (MTH1) to mitigate oxidation-induced DNA lesions. Therefore, a novel sequential nano-catalytic platform MCTP-FA was developed in which ultrasmall cerium oxide nanoparticle (CeO2 NP) decorated dendritic mesoporous silica NPs (DMSN NPs) were used as the core, and after encapsulation of MTH1 inhibitor TH588, folic acid-functionalized polydopamine (PDA) was coated on the periphery. Once endocytosed into the tumor, CeO2 with multivalent elements (Ce3+/4+) could transform H2O2 into highly toxic OH through a Fenton-like reaction to attack DNA as well as eliminating GSH through a redox reaction to amplify oxidative damage. Meanwhile, controllable release of TH588 hindered the MTH1-mediated damage repair process, further aggravating the oxidative damage of DNA. Thanks to the excellent photothermal performance of the PDA shell in the near-infrared (NIR) region, photothermal therapy (PTT) further improved the catalytic activity of Ce3+/4+. The therapeutic strategy of combining PTT, CDT, GSH-consumption and TH588-mediated amplification of DNA damage endows MCTP-FA with powerful tumor inhibition efficacy both in vitro and in vivo.