Tumor Microenvironment-Triggered Aggregated Magnetic Nanoparticles for Reinforced Image-Guided Immunogenic...

Anticancer therapies, which can induce cell death and elevate antitumor immune response in the meantime, are considered as effective treatments for many types of cancers. Immunogenic cell death (ICD) induced by chemodrugs is a promising and typical strategy to achieve cell cytotoxicity and immunological enhancement together. However, due to the low level of ICD induction and less tumor-targeting accumulation, application of traditional ICD inducers is limited. Here, tumor-targeting core-shell magnetic nanoparticles (ETP-PtFeNP:α-enolase targeting peptide modified Pt-prodrug loaded Fe₃O₄ nanoparticles) are developed to reinforce ICD induction of loaded-oxaliplatin (IV) prodrug. After tumor-targeting accumulation and endocytosis, platinum (IV) complexes are activated by intracellular reductive elimination to yield and release the Pt (II) congener, oxaliplatin, leading to DNA lesions and reactive oxygen species (ROS) generation. Simultaneously, in-progress-released ferric ions elicit highly toxic ROS (·OH or ·OOH) burst and interfere with the intracytoplasmic redox balance (like endoplasmic reticulum stress), leading to ICD-associated immunogenicity enhancement and specific antitumor immune responses to kill the tumor cells synergistically. Meanwhile, the transverse relaxation rate R ₂ of ETP-PtFeNP is remarkably increased by more than three times while triggered by reductant, suggesting ETP-PtFeNP a high-sensitivity T ₂ contrast agent for magnetic resonance imaging.