Structure-Activity Relationship of 3-Methylcytidine-5 '-alpha,beta-methylenediphosphates as CD73 Inhibitors

: Scortichini Mirko, Idris Riham Mohammed, Moschutz Susanne, Keim Antje, Salmaso Veronica, Dobelmann Clemens, Oliva Paola, Losenkova Karolina, Irjala Heikki, Vaittinen Samuli, Sandholm Jouko, Yegutkin Gennady G, Sträter Norbert, Junker Anna, Müller Christa E, Jacobson Kenneth A

Publisher: AMER CHEMICAL SOC

: 2022

: Journal of Medicinal Chemistry

: JOURNAL OF MEDICINAL CHEMISTRY

: J MED CHEM

: 65

: 3

: 2409

: 2433

: 25

: 0022-2623

: 1520-4804

DOI: https://doi.org/10.1021/acs.jmedchem.1c01852(external)

: https://pubs.acs.org/doi/10.1021/acs.jmedchem.1c01852(external)

We recently reported N-4-substituted 3-methylcytidine-5'-alpha,beta-methylenediphosphates as CD73 inhibitors, potentially useful in cancer immunotherapy. We now expand the structure-activity relationship of pyrimidine nucleotides as human CD73 inhibitors. 4-Chloro (MRS4598 16; K-i = 0.673 nM) and 4-iodo (MRS4620 18; K-i = 0.436 nM) substitution of the N-4-benzyloxy group decreased K-i by similar to 20-fold. Primary alkylamine derivatives coupled through a p-amido group with a varying methylene chain length (24 and 25) were functionalized congeners, for subsequent conjugation to carrier or reporter moieties. X-ray structures of hCD73 with two inhibitors indicated a ribose ring conformational adaptation, and the benzyloxyimino group (E configuration) binds to the same region (between the C-terminal and N-terminal domains) as N-4-benzyl groups in adenine inhibitors. Molecular dynamics identified stabilizing interactions and predicted conformational diversity. Thus, by N-4-benzyloxy substitution, we have greatly enhanced the inhibitory potency and added functionality enabling molecular probes. Their potential as anticancer drugs was confirmed by blocking CD73 activity in tumor tissues in situ.