NNMT inhibition in cancer-associated fibroblasts restores antitumor immunity.
Ontology highlight
ABSTRACT: Cancer-associated fibroblasts (CAFs) play a pivotal cancer-supportive role, yet CAF-targeted therapies remain elusive. Through spatial transcriptomics and single-cell RNA sequencing, we investigated the role of nicotinamide N-methyltransferase (NNMT) in high-grade serous ovarian cancer (HGSOC). Mechanistically, NNMT-induced H3K27me3 hypomethylation drives complement secretion from CAFs, attracting immunosuppressive myeloid-derived suppressor cells (MDSCs) to the tumor. NNMT knockout in immunocompetent mice impaired tumor growth in syngeneic ovarian, breast, and colon tumor models through enhanced CD8+ T cell activation. Using high-throughput screening, we developed a potent and specific NNMT inhibitor that reduces tumor burden and metastasis in multiple murine cancer models and restores immune checkpoint blockade efficacy by decreasing CAF-mediated MDSC recruitment and reinvigorating CD8⁺ T cell activation. Our findings establish NNMT as a central CAF regulator and promising therapeutic target to mitigate immunosuppression in the tumor microenvironment.
ORGANISM(S): Homo sapiens
PROVIDER: GSE295028 | GEO | 2025/05/09
REPOSITORIES: GEO
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