Targeting Hypoxic Tumors with Hybrid Nanobullets for Oxygen-Independent Synergistic Photothermal and Thermodynamic Therapy

Hypoxia is a feature of solid tumors and it hinders the therapeutic efficacy of oxygen-dependent cancer treatment. Herein, we have developed all-organic oxygen-independent hybrid nanobullets ZPA@HA-ACVA-AZ for the “precise strike” of hypoxic tumors through the dual-targeting effects from surface-modified hyaluronic acid (HA) and hypoxia-dependent factor carbonic anhydrase IX (CA IX)-inhibitor acetazolamide (AZ). The core of nanobullets is the special zinc (II) phthalocyanine aggregates (ZPA) which could heat the tumor tissues upon 808-nm laser irradiation for photothermal therapy (PTT), along with the alkyl chain-functionalized thermally decomposable radical initiator ACVA-HDA on the side chain of HA for providing oxygen-independent alkyl radicals for ablating hypoxic cancer cells by thermodynamic therapy (TDT). The results provide important evidence that the combination of reverse hypoxia hallmarks CA IX as targets for inhibition by AZ and synergistic PTT/TDT possess incomparable therapeutic advantages over traditional (reactive oxygen species (ROS)-mediated) cancer treatment for suppressing the growth of both hypoxic tumors and their metastasis. Highlights: 1 An all-organic hybrid nanobullets labeled as ZPA@HA-ACVA-AZ NBs was developed for the “precise strike”of hypoxic tumors through an oxygen-independently synergistic PTT/TDT, possessing therapeutic advantages over traditional ROS-mediated cancer treatment.2 By feat of dual-targeting effect from surface-modified HA (targeting CD44 receptors) and AZ (targeting CA IX), the nanobullets accumulated at hypoxic tumors efficiently.3 The synergism of intelligent nanobullets could suppress the primary breast tumor growth and lung metastasis via CA IX inhibition by AZ and synergistic PTT/TDT.