High intensity forced ultrasound-driven ferroptosis as a strategy for anti-tumor immune priming.

Cold tumors have a poor response to tumor immunotherapy due to low immune cell infiltration and the ability to evade immune attacks. Converting cold tumors into hot tumors can enhance the clinical effectiveness of anti-tumor immunotherapy. High-intensity focused ultrasound (HIFU) as a non-invasive treatment can damage tumors through mechanical effects, but there is a lack of research on its cytotoxic mechanisms at the cellular level and its role in inducing anti-immune responses. In this study, the role of HIFU in triggering tumor ferroptosis by disrupting the GSH/GSSG balance through mechanochemical action and the associated anti-tumor immune priming effect were investigated. The use of a nano-enhancer loaded with PFOB combined with HIFU could enhance ferroptosis in triple-negative breast cancer at a specific stage of tumor growth (UTGR = 0) while promoting the conversion of a cold tumor into a hot tumor, thereby improving the immune response. Overall, this provides valuable guidance for the clinical application of HIFU in tumor immunotherapy.