Tumors lose their privileges

A key challenge for cancer vaccine development is the ability of tumors to evade the immune system. Research published by a group at the University of Pennsylvania identified a key target in the process-the endothelin B receptor on tumor endothelial cells-that could provide an adjunct strategy for overcoming characteristics of the solid tumor microenvironment that lower vaccine efficacy, such as hypoxia, high interstitial fluid pressure and low extracellular pH.¹

In the paper, published in the January issue of Nature Medicine, Ronald Buckanovich and colleagues showed that blocking the endothelin B receptor in mice with ovarian cancer resulted in an increase in tumor-infiltrating lymphocytes (TILs). Moreover, the increased homing of TILs to tumor cells resulted in the improved efficacy of a cancer vaccine. Mice treated with a cancer vaccine and a small-molecule endothelin B receptor antagonist had better antitumor responses than those receiving the vaccine alone...