A smart responsive NIR-operated chitosan-based nanoswitch to induce cascade immunogenic tumor ferroptosis via cytokine storm.

In this work we present a near-infrared (NIR)-operated nanoswitch based on chitosan nanoparticles (EpCAM-CS-co-PNVCL@IR780/IMQ NPs) that induces cascade immunogenic tumor ferroptosis via cytokine storm. The formulation was prepared by loading a photosensitiser (IR780) and an immunotherapeutic drug (imiquimod; IMQ) into temperature- and pH-responsive chitosan-based NPs functionalized with tumor-targeting aptamers. The EpCAM aptamer can chaperone the NPs selectively into cancer cells, and allow them to enter the cell nucleus. In vitro and in vivo assays revelaed that the NPs were able to effectively induce the immunogenic ferroptosis of cancer cells. Under NIR irradiation, EpCAM-CS-co-PNVCL@IR780/IMQ cause cell death in tumors via photothermal therapy. Moreover, IMQ promotes the maturation of dendritic cells (DCs), which then activate cytotoxic T-lymphocytes (CTLs); these T-cells go on to provide immunotherapy of metastatic tumor cells. The metastatic tumor cells can be induced to undergo ferroptosis by the addition of arachidonic acid (AA), which interacts with interferon cytokines (IFN-γ) released from CTLs.