Synthesis of Substituted 5′‐Aminoadenosine Derivatives and Evaluation of Their Inhibitory Potential toward CD73

Abstract

Derivatives of 5′‐aminoadenosine containing methyl carboxylate, methyl phosphonate, gem‐bisphosphonate, bis(methylphosphonate), and α‐carboxylmethylphosphonate or phosphonoacetate moieties were synthesized from key intermediate 5′‐aminonucleoside. These nucleotide analogues were envisaged as 5′‐mono‐ or diphosphate nucleoside mimics. All compounds were evaluated for CD73 inhibition in a cell‐based assay (MDA‐MB‐231) and toward the purified recombinant protein. Most of them failed to reach significant inhibition of AMP hydrolysis by CD73 at 100 μm. Among the new compounds, the most interesting candidates, 5 (5′‐deoxy‐5′‐N‐phosphonomethyladenosine) and 7 (5′‐deoxy‐5′‐N‐(ethoxyphosphorylacetate)adenosine), inhibited recombinant CD73 by 36 and 46 % and cellular CD73 by 61 and 45 % at 100 μm, respectively. Molecular modeling partially explains this lack of activity, as the initially predicted docking scores had been encouraging, especially for compound 9.

CD39 and CD73 as Promising Therapeutic Targets: What Could Be the Limitations?

“…This ADP analogue remains one of the strongest known inhibitors of CD73. However, some of its characteristics such as its low bioavailability, low metabolic stability and off-target effects limit its therapeutic use (Ghoteimi et al, 2019). For this reason, APCP became a prototype for drug development (Bhattarai et al, 2015;Corbelini et al, 2015;Bhattarai et al, 2020).…”

“…This and another small molecule inhibitor (LY3475070) are currently being evaluated in phase one clinical trials. In addition to APCP based inhibitors of CD73, descriptions of numerous other inhibitors of the enzyme can be found in the literature (Figueiró et al, 2014;Baqi, 2015;Yang et al, 2017;Ghoteimi et al, 2019;Iqbal et al, 2020;Viviani et al, 2020). Finally, nucleoside analogues with two carboxylate groups and benzothiazine derivatives are CD73 inhibitors for treating cancer that have been patented (Gong et al, 2018;Ghoteimi et al, 2019).…”

4-Substituted-1,2,3-triazolo nucleotide analogues as CD73 inhibitors, their synthesis, in vitro screening, kinetic and in silico studies

“…1) exhibited higher activity than AOPCP. We also proposed another type of analogues where the 5'aminoadenosine moiety was used as a scaffold allowing us to perform di-substitution at the 5' position [20,24] and to replace the labile P-O-C5' linkage. However, these modifications failed to give significant inhibition of CD73 compared to AOPCP and previously reported analogues.…”

Targeting Metabolism of Extracellular Nucleotides via Inhibition of Ectonucleotidases CD73 and CD39

“…Because of its low sensitivity, the MG assay also requires high substrate concentrations that are generally greater than the K m value of the substrate. Despite these limitations, the MG assay platform has been extensively applied in the discovery of small-molecule CD73 inhibitors. − For example, researchers at Calithera Biosciences used an MG assay to evaluate inhibitors of both hCD73 (0.5 nM final concentration) and cellular CD73 in SK-MEL-28 cells, using 50 and 100 μM AMP, respectively. , Similarly, researchers at Arcus Biosciences, − ORIC Pharmaceuticals, − and Peloton Therapeutics have employed MG assays to evaluate small-molecule inhibitors against hCD73 or cellular CD73 (U138 or CHO cells). In a representative example, under conditions optimized for the evaluation of recombinant hCD73 (2 μg/mL enzyme, a 90 min reaction time, and 40 μM AMP), the MG assay yielded an IC 50 for AMPCP of 1.1 ± 0.03 μM …”