Reshaping Immunosuppressive Tumor Microenvironment Using Ferroptosis/Cuproptosis Nanosensitizers for Enhanced Radioimmunotherapy

Radiotherapy, a traditional cancer treatment, not only controls local tumor growth but also potentially induces immunogenic cell death, initiating systemic immune responses. However, radiotherapy resistance and immunosuppressive tumor microenvironments often limit the potency of radiation-induced anti-tumor immune responses, rendering them insufficient for clinical applications. Consequently, trimetallic nanoparticles are constructed with dual enzymatic activity, AuBiCu-distearoyl phosphoethanolamine-PEG nanoparticles (AuBiCu-PEG NPs), to synergistically improve radiotherapy resistance through X-ray deposition, hypoxia alleviation, and ferroptosis and cuproptosis induction. This approach promotes radiotherapy-induced immunogenic cell death and boosts anti-tumor immune responses. Furthermore, AuBiCu-PEG NPs effectively reversed radiation-induced upregulation of programmed cell death 1 ligand 1 (PD-L1), inhibit tumor immune evasion, and reshaped the immune microenvironment. Non-invasive and real-time longitudinal monitoring of nanoparticle accumulation in tumors can be achieved using spectral computed tomography (CT) and photoacoustic (PA) imaging. In summary, the designed AuBiCu-PEG NPs serve as promising nanoplatforms for immune microenvironment remodeling and can be used in multimodal molecular imaging-guided ferroptosis-cuproptosis-enhanced radiotherapy. To overcome the radiotherapy resistance and regulate the immunesuppressive tumor microenvironment, a strategy of trimetallic AuBiCu-PEG nanoparticles is proposed in this study. Due to their high-Z properties, the nano-sensitizer can enhance the efficacy of radiotherapy, induce immunogenic cell death and ferroptosis/cuproptosis to evoke tumor immunogenicity. Additionally, the spectral CT and photoacoustic imaging facilitate noninvasive monitoring of nanoparticle accumulation in tumors. image