CD44-targeted RIP3 gene delivery strategy for enhanced cancer therapy via necroptosis and immune modulation

Receptor-interacting protein kinase 3 (RIP3)-mediated necroptosis has attracted interest as a potential target for cancer therapy as it boosts tumor immunogenicity. Here, we synthesized a pH-sensitive polymer (CA) by conjugating aminopropyl imidazole (API) to chondroitin sulfate (CHS) for RIP3 gene delivery. CA can target cancer cells due to the specific binding ability of CHS to CD44 which is overexpressed in cancer cells. In addition, the introduction of API conferred pH sensitivity, facilitating efficient endosomal escape and enhancing gene delivery efficiency. Increased levels of high mobility group box-1, EEA1, and Rab5 and high activation of RIP3/mixed-lineage kinase domain-like pseudokinase (MLKL) signaling were observed in the CA-shielded RIP3 complex (CA-PEI/RIP3)-treated groups. Significant tumor selectivity and ablation efficacy of CA-PEI/RIP3 were confirmed in A549 xenografts and LLC1 orthotopic lung cancer mouse models. Furthermore, CA-PEI/RIP3-induced necroptotic cell death could enhance the immune response by increasing phagocytosis of dendritic cells (DCs), resulting in large numbers of CD4+ and CD8+ T cells and mature DCs infiltrating tumor tissues and lymph nodes. Collectively, CA-PEI/RIP3 showed significant potential in cancer gene therapy due to the enhanced transfection efficiency and the tumor-targeting properties of CA, providing a safe and robust strategy to activate the immune response for cancer immunotherapy.