Fig. 1. A schematic illustration of the ICIE strategy for killing both primary and distant/metastatic tumors.

ICIE combines cryosurgery with intravenously injected (i.v.) irinotecan (or camptothecin/CPT) and PD-L1 silencing siRNA (siR)-laden cold-responsive nanoparticles (CPT&siR CRNPs) to engineer the tumor microenvironment (TME), via promoting immunogenic cell death (ICD) and reducing the expression of programmed death Ligand 1 (PD-L1) in cancer cells. This turns the TME from immunologically “cold” (i.e., immunosuppressive) into immunologically “hot” (i.e., immuno-active). As a result, the CD8⁺ T cells can be activated to exert tumor eradication both locally and systemically. The CPT&siR CRNPs are prepared by a double-emulsion method detailed in the Methods section using CPT, siR, Poly (D, L-lactide-co-glycolide) (PLGA), poly (N-isopropylacrylamide copolymerized butyl acrylate) (pNIPAAm-BA), chitosan-modified PF-127 (CS-PF-127), 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), and sodium chloride (NaCl). HMGB1: high mobility group box protein 1, CRT: calreticulin, HSP-70: heat shock protein-70, HSP-90: heat shock protein-90, DC: dendritic cell, and T_EM: effective memory T cell.