Photothermal therapy (PTT) is a potential treatment for cancer that makes use of near-infrared (NIR) laser irradiation and is expected to assist traditional anti-cancer drug therapies; however, the therapeutic efficacy of PTT is restricted by thermal resistance due to the overexpression of heat shock proteins and insufficient penetration depth of lasers. Thus, PTT needs to be combined with additional therapeutic methods to obtain the optimal therapeutic efficacy for cancer. Herein, a multifunctional therapeutic platform combining PTT with glucose-triggered chemodynamic therapy (CDT) and glutathione (GSH)-triggered hypoxia relief was developed via GOx@MBSA-PPy-MnO2 NPs (GOx for glucose oxidase, M for Fe3O4, BSA for bovine serum albumin, and PPy for polypyrrole). GOx@MBSA-PPy-MnO2 NPs have excellent photothermal efficiency and can release Mn2+, which catalyzes the transformation of H2O2 into hydroxyl radicals (·OH) and O2 via a Fenton-like reaction, effectively destroying cancer cells and relieving tumor hypoxia. Meanwhile, a high content of H2O2 was produced via GOx catalysis of glucose, further enhancing the CDT efficiency. In addition, in vitro and in vivo experiments showed that the inhibition of cancer cell proliferation and effective inhibition of tumors could be caused by the combined PTT/glucose-triggered CDT effects and hypoxia relief of the GOx@MBSA-PPy-MnO2 NPs. Overall, this work provides evidence of a synergistic therapy that remarkably improves therapeutic efficacy and significantly prolongs the lifetime of mice compared with controls.
Keywords: bladder cancer; chemodynamic therapy; manganese dioxide (MnO2); photothermal therapy; tumor hypoxia.