PRJNA556574
A single cell atlas of tumor resistance to PD-1 blockade and radiotherapy: Tumor vs Liver Whole Exome Sequencing
Abstract: Transplanted tumors in syngeneic mice treated with immune checkpoint blockade and radiotherapy demonstrate synergy and an abscopal effect. Indeed, tumors generated from sarcoma cell lines transplanted into syngeneic mice are cured by PD-1 blockade and radiotherapy, but autochthonous, primary sarcomas from the same high mutational load model are resistant to the identical treatment. Here, we generated a single cell atlas of tumor-infiltrating immune cells from allograft and primary tumors, which demonstrates marked differences in their immune landscapes before and after radiation and immunotherapy. Allograft tumors are enriched for effector CD8+ T cells that mediate response to combination therapy, but the immune response to primary sarcomas shows tumor-specific tolerance. Genetic barcoding of primary tumors reveals a cellular response to combination therapy, but resistance of specific clones. Together, this comprehensive comparison of the primary and allograft tumor microenvironments identifies immune tolerance and clonal resistance to immunotherapy and radiotherapy specific to primary tumors. These filesMethods: Primary and allograft sarcomas were harvested 3 days after treatment with either 0 or 20 Gy radiation and anti-PD-1 or isotype control treatment.