Anales RANF

P.27 SYNTHESIS OF FLUORESCENCE-LABELED AMP AND ADENOSINE DERIVATIVES AS TOOLS FOR MONITORING CD73 ACTIVITY G. Rolshoven, L. Schäkel, S.-Y. Lee, C.E. Müller University of Bonn, North Rhine-Westphalia, Germany. Ecto-5 ʹ -Nucleotidase ( e N, CD73) is an ecto-enzyme which catalyzes the hydrolysis of extracellular nucleoside-5 ʹ -monophosphates, mainly AMP, leading to the formation of adenosine. Adenosine activates G protein-coupled adenosine receptors which results in anti-inflammatory, immunosuppressive and tumor-promoting effects. Blockade of CD73 has been proposed as a novel strategy in immuno-oncology. The aim of the current work was to develop and establish a new fluorescence-based CD73 assay which would avoid the use of radioactive substrate and allow high sensitivity. To this end, we designed a fluorescence-labeled CD73 substrate ( I ), and developed a synthetic pathway to obtain I and its hydrolysis product II . Preliminary biological experiments showed that CD73 converts fluorescence-labeled AMP derivative I to the corresponding adenosine derivative II . In future studies, we will utilize I to monitor CD73 reactions to establish a new fluorescence-based CD73 assay.