Hypoxia-specific metal-organic frameworks combined with lactate immunometabolism regulation augment anti-tumor immunity of HIFU

High-intensity focused ultrasound (HIFU) has emerged as one of the preferred modalities for breast-conserving oncotherapy, and immune response it triggers is key to prognosis. Nevertheless, its immunotherapy efficacy is often compromised by the postoperative tumor microenvironment (TME) featured by severe hypoxia and lactate accumulation, leading to subsequent tumor recurrence and metastasis. In this work, we designed hypoxia-specific metal-organic frameworks (AMCMOFs) that co-deliver the hypoxia-activated prodrug AQ4N and CaCO 3 , aiming to enhance tumor immunogenicity and reversing immunosuppression brought by severe hypoxia and elevated lactate in the TME after HIFU surgery. AMCMOFs utilize hypoxia aggravated by HIFU to activate AQ4N, ultimately inducing immunogenic cell death. Meanwhile, CaCO 3 neutralizes intratumoral lactate, reprogramming tumor-associated macrophages from immunosuppressive M2 phenotype toward pro-inflammatory M1 phenotype. Furthermore, the co-release of calcium and manganese ions trigger pyroptosis via mitochondrial ion overload and activate calcium-dependent NFAT pathway of T cells. As a result, AMCMOFs elicit the strong immune response and successfully induce long-lasting immune memory, effectively inhibiting tumor recurrence and metastasis. Therefore, the developed MOFs-based nanoplatform can combine the utilization and regulation of TME, offering a compelling strategy for improving the prognosis of all surgical operations, including HIFU, in oncotherapy.