A Two-Pronged Nanostrategy of Iron Metabolism Disruption to Synergize Tumor Therapy by Triggering the Paraptosis–Apoptosis Hybrid Pathway

Iron metabolism has emerged as a promising target for cancer therapy; however, the innate metabolic compensatory capacity of cancer cells significantly limits the effectiveness of iron metabolism therapy. Herein, bioactive gallium sulfide nanodots (GaS_x), with dual functions of "reprogramming" and "interfering" iron metabolic pathways, were successfully developed for tumor iron metabolism therapy. The constructed GaS_x nanodots ingeniously harness hydrogen sulfide (H₂S) gas, which is released in response to the tumor microenvironment, to reprogram the inherent transferrin receptor 1 (TfR1)-ferroportin 1 (FPN1) iron metabolism axis in cancer cells. Concurrently, the gallium ions (Ga³⁺) derived from GaS_x act as a biochemical "Trojan horse", mimicking the role of iron and displacing it from essential biomolecular binding sites, thereby influencing the fate of cancer cells. By leveraging the dual mechanisms of Ga³⁺-mediated iron disruption and H₂S-facilitated reprogramming of iron metabolic pathways, GaS_x prompted the initiation of a paraptosis-apoptosis hybrid pathway in cancer cells, leading to marked suppression of tumor proliferation. Importantly, the dysregulation of iron metabolism induced by GaS_x notably increased tumor cell susceptibility to both chemotherapy and immune checkpoint blockade (ICB) therapy. This study underscores the therapeutic promise of gas-based interventions and metal ion interference strategies for the tumor metabolism treatment.