Endogenous/exogenous dual-responsive nanozyme for photothermally enhanced ferroptosis-immune reciprocal synergistic tumor therapy

Apoptosis resistance and immune evasion of tumor cells substantially increase the risk of cancer treatment failure. Here, a multifunctional nanozyme MET-CMS@FeTA (MCMSFT) formulated to induce nonapoptotic ferroptosis and boost immune recognition/attack, where compensatory mechanisms collectively overcome intrinsic tumor therapeutic limitations and improve medical intervention outcomes. Leveraging the multienzyme-like activity of MCMSFT to achieve oxygen generation, hydroxyl radical production, and glutathione depletion promotes hypoxia relief and triggers apoptosis/ferroptosis. Notably, MCMSFT-mediated photothermal therapy (PTT) facilitates direct tumor thermal ablation and offers exogenous heat to accelerate nanocatalytic reactions. Furthermore, PTT/ferroptosis-caused immunogenic cell death favors antitumor immunity initiation. Simultaneously, metformin administration and hypoxia amelioration down-regulate programmed death ligand 1 alleviating immune evasion. Interferon-γ secretion poses positive feedback to ferroptosis, thereby establishing a ferroptosis-immune mutual amplification loop. Antitumor performances illustrate that MCMSFT eliminates primary tumors and suppresses metastasis/rechallenge tumors. Collectively, MCMSFT surmounts the predicament of apoptosis resistance and immune evasion in cancer treatment to acquire more effective and comprehensive therapy efficacy.