Targeting the adenosine pathway for cancer immunotherapy.

Suppression of anti-tumor immunity is recognized as a critical step in the development of many types of cancers. Over the past decade, a multitude of immunosuppressive pathways occurring in the tumor microenvironment (TME) have been identified. Amongst them, the hydrolysis of extracellular ATP into adenosine by ecto-nucleotidases has been increasingly documented as new immune checkpoint pathway that can significantly impair anti-tumor immunity of multiple types of cancer. In this review, we summarize past and recent research on the ecto-nucleotidases CD39 and CD73, conducted by our group and others, that recently lead to the development and clinical testing of adenosine targeting agents for cancer immunotherapy.