Tumor-Specific Gene Editing Enhances Cancer Immunogenicity through Succinate Metabolism-Mediated MHC-I Reprogramming

Abstract

Impaired expression of major histocompatibility complex class I (MHC-I) greatly compromises cytotoxic T-cell-mediated anticancer immunotherapy. Existing MHC-I activation strategies are greatly challenged by poor tumor specificity and off-target toxicity. Herein, we report a dual tumor-specific CRISPR/Cas9 gene editing system that can precisely knock out succinate dehydrogenase subunit C (Sdhc) to activate the MHC-I pathway via epigenetic and transcriptional regulation. A tumor-specific gene editor is first engineered via reversible shielding of sgRNA using an apurinic/apyrimidinic endonuclease 1 (APE1)-responsive, complementary ssDNA, yielding AP-sgRNA with blocked editing activity in normal cells yet completely restored activity in APE1-overexpressing tumor cells. Subsequently, tumor-targeted delivery of AP-sgRNA and Cas9 mRNA (mCas9) is achieved using dibenzocyclooctyne-decorated lipid nanoparticle (DLNP), which upon bioorthogonal click reaction can anchor cancer cells that are prelabeled with azido groups using the unnatural sugar DCL-AAM. Thus, AP-sgSdhc/mCas9@DLNP enables efficient and selective Sdhc editing in tumor cells, leading to epigenetic and transcriptional activation of MHC-antigen processing and presentation genes and thereby provoking robust antitumor efficacy in the B16-OVA melanoma model through enhanced, T cell-mediated immune responses. Moreover, it completely suppressed pulmonary metastasis after combination with aPD-L1 in the 4T1 lung metastasis model. This study provides an enlightened paradigm for precision gene editing and renders a promising mechanism for potentiating cancer immunotherapy.