Nanoparticles-mediated dual metabolic-immunological intervention reverses immunosuppression in muscle invasive bladder cancer.

Muscle-invasive bladder cancer (MIBC) is an aggressive urological malignancy characterized by a profoundly immunosuppressive tumor microenvironment (TME) driven by dysregulated oncogenic metabolism. The oxidoreductase NAD(P)H:quinone oxidoreductase 1 (NQO1) stabilizes the core metabolic regulator hypoxia-inducible factor 1α (HIF-1α), which further transcriptionally activates the homeobox transcription factor SIX1, forming a coordinated NQO1/HIF-1α/SIX1 signaling axis that drives metabolic reprogramming and immune evasion in MIBC, yet targeted therapies disrupting this metabolic-immune nexus remain clinically unavailable. Here, we developed a biomimetic macrophage membrane-cloaked nanoplatform (MMP@siN/NC) for targeted co-delivery of NQO1-targeting siRNA (siNQO1) and the SIX1 small-molecule inhibitor NCGC, with a PEG-PDLLA/DOTAP hybrid core enabling prolonged systemic circulation, enhanced tumor targeting, efficient cellular internalization, facilitated endosomal escape, and synergistic drug release. In vitro, MMP@siN/NC exerted robust cytotoxicity against MIBC cells, induced potent immunogenic cell death (ICD), and suppressed aerobic glycolysis and tricarboxylic acid (TCA) cycle flux via axis blockade, which further promoted dendritic cell maturation, M1 macrophage polarization, and tumor-specific T-cell priming. In vivo, MMP@siN/NC potently inhibited tumor growth, elicited a systemic abscopal effect, and established durable anti-tumor immune memory in subcutaneous MIBC models, with strong synergistic efficacy in combination with anti-CTLA-4 (αCTLA4) immune checkpoint blockade. Critically, in a clinically relevant orthotopic MIBC model, the nanosystem exhibited excellent tumor accumulation, significant therapeutic efficacy, prolonged survival, and a favorable safety profile. Collectively, this work validated the NQO1/HIF-1α/SIX1 axis as a targetable metabolic-immune driver in MIBC, and presented a translatable nanotherapeutic strategy to simultaneously disrupt tumor metabolism and reactivate anti-tumor immunity for MIBC treatment.