Regulation of PD-1 in T cells for cancer immunotherapy.

Study of the molecular mechanisms underlying cancer immune escape is one of the core issues in immuno-oncology research. Cancer cells can evade T cell cytotoxicity by exploiting the upregulation of T cell inhibitory receptors on T cells and their ligands on cancer cells. These upregulated proteins include the inhibitory receptor programmed cell-death protein 1 (PD-1) and its ligand programmed cell death 1 ligand 1 (PD-L1), which can induce T cell exhaustion and reduce T cell activation. Characterizing PD-1 regulation will help to elucidate the molecular mechanisms underlying T cell exhaustion and improve cancer treatment. Recent studies have found that tumor cells regulate PD-1 during gene transcription, post-transcriptional regulation, and post-translational modification and influence the effects of the anticancer immune response by targeting PD-1. In this review,we summarize the mechanisms of PD-1 regulation in T cells.