Programmed Cell Death 1 checkpoint inhibitors as cancer therapies

Abstract

CD279 protein, also well known as the programmed-cell-death-protein-1 or PD-L1, is identified as a surface protein found primarily on T lymphocytes, and B cells, serving for regulating autoimmune responses. It functions by limiting T cell inflammatory responses towards self-cells, preventing autoimmune diseases but at the same time forestalling the immune system from killing cancer cells. PD-1 along with its receptor programmed-cell-death-protein-1-ligand, or PD-L1, forms the programmed cell death pathway which promotes the programmed cell death or apoptosis of antigen specific cytotoxic T lymphocytes in the lymph nodes through self-selection, supporting survival of T regulatory cells by limiting apoptosis events among these cells. It is commonly used as a target for immune checkpoint and monoclonal antibody treatments in certain cancer types, therefore understanding the mechanism of the PD1 pathway is crucial for development of combined immunotherapies and prognosis. Most treatments blocks PD-1 in order to initiate anti-tumor activities by galvanizing T cell activities. However, for certain types of cancer and some patients prone to develop drug resistances, PD-1 related cancer treatment may have unsatisfying result. In this paper, we focus on gathering the mechanism and treatment related with PD-1 pathway. We also discuss the ethics, safety, and side effects of particular drugs utilizing the PD-1 pathway and the promising future for combination therapies.