Self-oxygenating nanoplatform integrating CRISPR/Cas9 gene editing and immune activation for highly efficient photodynamic therapy

Photodynamic therapy (PDT) has arisen as a promising method due to its spatiotemporal precision and minimal invasiveness. It encounters significant obstacles in solid tumors due to hypoxia-induced therapeutic resistance and the self-protective mechanisms of cancer cells facilitated by MutT homolog 1 (MTH1), an enzyme involved in oxidative damage repair. Herein, we fabricate a tumor-microenvironment responsive CRISPR nanoplatform based on hollow mesoporous manganese dioxide (H-MnO2) for PDT. This platform utilizes H-MnO2 to produce oxygen (O2) through the decomposition of hydrogen peroxide (H2O2) in TME, thereby mitigating hypoxia and enhancing reactive oxygen species (ROS) generation. The high concentration of glutathione (GSH) and hyaluronidase (HAase) in TME induces the release of CRISPR/Cas9 ribonucleoproteins (RNP) to target the MTH1 gene, thereby impairs oxidative damage repair pathways and amplifys ROS-mediated cytotoxicity. The released Mn2+ ions function as immunomodulatory agents, activate innate immune responses via stimulating STING signal pathway. In vitro, IHMRH NPs markedly increased intracellular O2 levels, ROS production, lipid peroxidation and DNA damage, leading to tumor cell death, immune activation, and effective gene editing. In vivo, the nanoplatform suppressed tumor growth, diminished MTH1 gene expression, stimulated dendritic cell (DC) maturation through immunogenic cell death (ICD). This multimodal nanosystem may amplifies oxidative stress, collaborates with innate and adaptive immune activation to surpass the constraints of traditional PDT. The research presents a novel framework for cancer combination therapy by systematically integrating nanotechnology with precision gene editing.