Re-engineering the Immune Response to Metastatic Cancer: Antibody-Recruiting Small Molecules Targeting the Urokinase Receptor.

Developing selective strategies to treat metastatic cancers remains a significant challenge. Herein, we report the first antibody-recruiting small molecule (ARM) that is capable of recognizing the urokinase-type plasminogen activator receptor (uPAR), a uniquely overexpressed cancer cell-surface marker, and facilitating the immune-mediated destruction of cancer cells. A co-crystal structure of the ARM-U2/uPAR complex was obtained, representing the first crystal structure of uPAR complexed with a non-peptide ligand. Finally, we demonstrated that ARM-U2 substantially suppresses tumor growth in vivo with no evidence of weight loss, unlike the standard-of-care agent doxorubicin. This work underscores the promise of antibody-recruiting molecules as immunotherapeutics for treating cancer.