Dissection of the T-cell infiltrate in mouse pancreatic tumors reveals an extensive and diverse tumor-reactive T-cell repertoire
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ABSTRACT: Background: Pancreatic ductal adenocarcinoma (PDAC) is refractory to cytostatic and immunotherapeutic treatment regimens, including immune checkpoint inhibition (ICI). The latter is due to the limited mutational load of most of these tumors, in combination with the immunosuppressive hurdles imposed by the tumor microenvironment. Here we present an in-depth analysis of the T-cell response at the single-cell level in an orthotopic PDAC mouse model that recapitulates the therapy resistance of the human disease. In parallel, we investigated an ICI-sensitive variant of this model expressing an immunogenic neo-antigen. Methods: Single-cell RNA and T-cell receptor (TCR) from tumor-infiltrating lymphocytes (TILs) of 14 tumor-bearing mice were combined with functional in vitro screening of TCR specificity against tumor. Transcriptomic differences between tumor-reactive (TR) and non-tumor-reactive (NTR) T-cells were harnessed to define gene signatures for the purpose of predicting the specificity of additional TCRs. Results: Our efforts revealed extensive tumor-reactive and bystander CD8+ and CD4+ T-cell repertoires, not only in the immunogenic but also in the ICI-refractory tumors. By integrating the functional screening and single-cell transcriptome data sets, we delineated gene signatures that distinguish between tumor-reactive and bystander T-cells in the mouse model as well as in human cancers. The TCRs in the murine models detect a range of tumor-associated antigens beyond mutanome-encoded neoepitopes and retain functional anti-tumor activity in vitro.
ORGANISM(S): Mus musculus
PROVIDER: GSE217121 | GEO | 2025/06/01
REPOSITORIES: GEO
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