The antitumor activity of
disulfiram (DSF), a traditional US Food and Drug Administration-approved drug for the treatment of "
alcohol-dependence", is Cu2+-dependent, but the intrinsic anfractuous biodistribution of
copper in the human body and
copper toxicity induced by exogenous
copper supply have severely hindered its in vivo application. Herein, we report an in situ Cu2+ chelation-enhanced DSF-based
cancer chemotherapy technique, using a
tumor-specific "nontoxicity-to-toxicity" transition strategy based on hollow mesoporous
silica nanoparticles as the functional carrier. Cu2+-doped, DSF-loaded hollow mesoporous
silica nanoparticles were constructed for the rapid release of Cu2+
ions induced by the mild acidic conditions of the tumor microenvironment. This resulted in the rapid biodegradation of the nanoparticles and accelerated DSF release once the particles were endocytosed into
tumor cells. The resulting in situ chelation reaction between the coreleased Cu2+
ions and DSF generated toxic CuET products and concurrently, Fenton-like reactions between the generated Cu+
ions and the high levels of H2O2 resulted in the production of
reactive oxygen species (ROS) in the acidic tumor microenvironment. Both in vitro cellular assays and in vivo
tumor-xenograft experiments demonstrated the efficient Cu-enhanced and
tumor-specific chemotherapeutic efficacy of DSF, with cocontributions from highly toxic CuET complexes and ROS generated within
tumors. This work provides a conceptual advancement of nanoparticle-enabled "nontoxicity-to-toxicity" transformation in
tumors, to achieving high chemotherapeutic efficacy and biosafety.