Tumor-infiltrating, adoptively transferred BATF-overexpressing CD8 T cells analyzed via bulk RNA-seq

In cancer, tumor infiltrating lymphocytes (TILs) often differentiate into dysfunctional states, re-sembling exhausted T cells that arise in chronic viral infections. The dysfunctional state of exhaustion in CD8 T cells is characterized by diminished effector function, namely decreased cytotoxic activity and reduced expression of effector molecules, such as granzyme B. BATF is a transcription factor (TF) known to promote the differentiation of effector CD8 T cells in the chronic viral infection model; however, its role in cancer is not well studied. Using bulk RNA-sequencing (bulk RNA-seq), we identified that BATF-overexpression in tumor-specific CD8 T cells exhibited enrichment for a gene set upregulated in early effector CD8 T cells compared to late exhausted CD8 T cells. Notably, BATF overexpression enhanced the gene expression of various activation markers, costimulatory molecules, effector molecules, chemokine receptors, and other transcription factors, including Hif1a. Additionally, GSEA analysis revealed that BATF-overexpressing CD8 T cells were negatively enriched for Reactome pathways of cellular responses to stress as well as stress-induced senescence. Collectively, our findings support BATF as a key regulator of effector CD8 T cell activity and function within the tumor and shed light on potential pathways BATF may upregulate to facilitate effective tumor control. 5 replicates of two treatment groups of tumor-bearing mice received adoptive cell transfer of Pmel CD8 T cells retrovirally-expressing either MIT-BATF or MIT-empty vector control.