The GPCR-Gα s -PKA signaling axis promotes T cell dysfunction and cancer immunotherapy failure.

Immune checkpoint blockade (ICB) targeting PD-1 and CTLA-4 has revolutionized cancer treatment. However, many cancers do not respond to ICB, prompting the search for additional strategies to achieve durable responses. G-protein-coupled receptors (GPCRs) are the most intensively studied drug targets but are underexplored in immuno-oncology. Here, we cross-integrated large singe-cell RNA-sequencing datasets from CD8 + T cells covering 19 distinct cancer types and identified an enrichment of Gα s -coupled GPCRs on exhausted CD8 + T cells. These include EP 2 , EP 4 , A 2A R, β 1 AR and β 2 AR, all of which promote T cell dysfunction. We also developed transgenic mice expressing a chemogenetic CD8-restricted Gα s -DREADD to activate CD8-restricted Gα s signaling and show that a Gα s -PKA signaling axis promotes CD8 + T cell dysfunction and immunotherapy failure. These data indicate that Gα s -GPCRs are druggable immune checkpoints that might be targeted to enhance the response to ICB immunotherapies.