Research Progress of Tumor Immunotherapy Target CD73 and Its Inhibitors

Adenosine has been proved to have immunosuppressive effect in many different diseases, and the activity of ecto-5’-nucleotidase(CD73) on the cell surface is the rate-limiting step of extracellular adenosine production. CD73 has a profound and lasting impact on tumor immune regulation of regulatory T cells, B cells, macrophages and natural killer cells. CD73-mediated adenosine pathway is significant in signal transduction during cancer progression in tumor microenvironment, making CD73 a novel immune checkpoint. Therefore, CD73 inhibition is a emergent and promising strategy for cancer immunotherapy. At present, a variety of monoclonal antibodies and small molecule inhibitors have been in clinical development. This review comprehensively summarizes the frontier research progress of reported small molecule CD73 inhibitors, which can provide guidance for the investigation of novel CD73 inhibitors for cancer therapy.