Targeting G Protein–Coupled Receptors in Immuno-Oncological Therapies

The advent of cancer immunotherapy based on PD-1 and CTLA-4 immune checkpoint blockade (ICB) has revolutionized cancer treatment. However, many cancers do not respond to ICB, highlighting the urgent need for additional approaches to achieve durable cancer remission. The large family of G protein–coupled receptors (GPCRs) is the target of more than 30% of all approved drugs, but GPCRs have been underexploited in cancer immunotherapy. In this review, we discuss the central role of GPCRs in immune cell migration and function and describe how single-cell transcriptomic studies are illuminating the complexity of the human tumor immune GPCRome. These receptors include multiple GPCRs expressed in CD8 T cells that are activated by inflammatory mediators, protons, neurotransmitters, and metabolites that accumulate in the tumor microenvironment, thereby promoting T cell dysfunction. We also discuss new opportunities to target GPCRs as a multimodal approach to enhance the response to ICB for a myriad of human malignancies.