Advances of PD1 PD-L1 Signaling Pathway in Tumor Immunotherapy

Abstract

Increasing clinical data has demonstrated the effectiveness of checkpoint blockade immunotherapy in cancer. Programmed death ligand-1 (PD-L1) and programmed cell death protien-1 (PD-1) as two promising targets of checkpoint blockade have received growing attention in treating various malignancies. This review introduces the basic biological mechanisms of PD-1 signaling regulation in T cells, the landscape of PD-L1 expression in tumor, and the advancement of PD-1/PD-L1 signaling pathway research in different cancer types. We will also discuss the limitations of antibody-based treatments and mechanisms related to PD-1/PD-L1 blockade resistance. In the end, we will also demonstrate potential solutions to overcome the challenges of current immunotherapy and the development of new therapeutic agents.  Overall, immunotherapies targeting PD-1/PD-L1 pathway provide opportunities to boost anti-tumor immunity while there’s still problems waiting to be solved to allow larger patient population to be benefited.