Engineered acid-regulating liposomal nanovesicles for synergistic photodynamic pyroptosis and immunotherapy

Gasdermin-mediated pyroptosis has emerged as a promising mechanism in cancer immunotherapy, however, its efficacy is often limited by inefficient activation within the immunosuppressive tumor environment. Herein, we generated an acid-regulating biomimetic liposomal nanovesicle (L-P-Cn-U) for the co-delivery of a photosensitizer prodrug (P-Cn) and a carbonic anhydrase IX (CAIX) inhibitor (U-104). By conducting efficacy screening of various P-Cn prodrugs within the L-P-Cn-U system, we identified L-P-C16-U with identical lipid tail structures, as the optimal candidate due to its strong colloidal stability and reactive oxygen species (ROS) generation efficiency. Our cellular and murine model studies demonstrated that L-P-Cn-U-mediated pyroptosis and immunogenic cell death could convert immunologically cold tumors into hot tumors, thereby enhancing antitumor immunity and concurrently inhibiting tumor cell migration. Mechanistic investigation revealed that the acid-triggered U-104 release from L-P-Cn-U augmented intracellular acidity through CAIX inhibition, which subsequently attenuated PI3K-Akt/mTOR signaling. This result enhances O₂-dependent ROS production and establishes a negative feedback loop for CAIX expression. Collectively, our findings provide a combinatorial strategy that integrates pyroptosis-focused therapy with metabolic regulation, offering a broadly applicable conception to augment cancer immunotherapy. STATEMENT OF SIGNIFICANCE: Herein, we report the rational design and synthesis of a new class of biomimetic liposome by integrating chemically engineered pH-responsive lipids (L-pH) with lipid-like photosensitizer prodrugs (P-Cn). Characterization studies demonstrated an optimal construct (L-P-C16) with identical lipid tails, showing robust stability and reactive oxygen species production. This optimized nanovesicle was subsequently co-loaded with the carbonic anhydrase inhibitor U-104. The resulting L-P-C16-U system was adequately investigated and shown to effectively synergize photodynamic therapy and immunotherapy. Our work provides new insights into liposome engineering strategies for combination tumor therapy.