Injectable pH-responsive gelatin methacryloyl hydrogel for cuproptosis-synergized sunitinib therapy and immune...

Clear cell renal cell carcinoma (ccRCC) remains a therapeutic challenge due to tyrosine kinase inhibitor (TKI) resistance and an immunosuppressive tumor microenvironment (TME). To avoid the limitations of systemic nanotherapeutics, which often suffer from inadequate tumor accumulation, we developed a pH-activatable injectable gelatin methacryloyl (GelMA) hydrogel (termed SUN/CuONPs@GelMA) for localized co-delivery of sunitinib and copper oxide nanoparticles. The photocrosslinkable GelMA matrix enables minimally invasive intratumoral administration and sustained drug retention. Unlike ferroptosis, which is frequently migigated by the antioxidant defenses inherent in ccRCC, cuproptosis circumvents this resistance by targeting mitochondrial metabolism. In the weakly acidic TME (pH 5.3-7), CuONP assemblies dissolve to release CuO nanoparticles and Cu²⁺, triggering dual mechanisms: (1) cuproptosis via mitochondrial proteotoxicity and the depletion of iron-sulfur cluster protein, and (2) Fenton-like reaction-mediated reactive oxygen species (ROS) generation and the release of damage-associated molecular patterns (DAMPs). Concurrently, sunitinib inhibits angiogenesis and synergizes with copper-driven immunomodulation to reprogram macrophages toward tumor-suppressive M1 phenotypes. In vitro and in vivo studies demonstrated potent tumor growth inhibition, migration suppression, and prolonged survival in ccRCC. The SUN/CuONPs@GelMA platform overcomes TKI resistance through the synergy of cuproptosis and immunotherapy. This localized co-delivery strategy provides a multi-mechanistic approach for the treatment of advanced ccRCC. STATEMENT OF SIGNIFICANCE: Systemic treatments for advanced clear cell renal cell carcinoma (ccRCC) are restricted by tyrosine kinase inhibitor (TKI) resistance, systemic toxicity, and an immunosuppressive tumor microenvironment (TME). We herein report a pH-activatable, injectable photocrosslinkable GelMA hydrogel for localized co-delivery of sunitinib and copper nanoparticles, enabling minimally invasive delivery, sustained drug retention, and reduced systemic toxicity. This hydrogel triggers cuproptosis via acidic TME-responsive copper release, and synergizes with sunitinib to reverse TKI resistance, suppress tumor progression and migration, reprogram immunosuppressive macrophages to antitumor phenotypes, and extend preclinical survival. This work establishes a combinatorial ccRCC therapeutic platform, providing a promising translational strategy for advanced ccRCC management.