Inducing lymphoid niches across cancers by tumor-to-dendritic cell reprogramming (141373)
Tertiary lymphoid structures (TLS) in tumors are associated with improved responses to immunotherapy, but their controlled induction remains elusive. Here, we used in vivo reprogramming of tumor cells into type-1 conventional dendritic cell (cDC1)–like cells to rewire the tumor microenvironment and induce immunogenic TLS (imgTLS) across melanoma, colon, bladder, breast and pancreatic cancer models with distinct genetic backgrounds. cDC1-like cells activated lymphotoxin, TNF, and interferon programs, and engaged early with T cells through MHC-I and CD40 signaling to induce imgTLS containing BCL6⁺ germinal centers, independently of endogenous cDC1s. Spatial transcriptomics identified DC-LAMP+ CCR7⁺ migratory cDC1s within nucleating niches enriched in CD4⁺, CD8⁺ T cells, and B cells in mouse and human tumors. ImgTLS sustained B cell and T cell responses, and promoted systemic immunity through clonal expansion in abscopal tumors. Together, our findings establish cellular reprogramming as a strategy to engineer intratumoral lymphoid niches and overcome resistance to immunotherapy.