3,4-Dihydropyrimidin-2(1H)-ones as Antagonists of the Human A2B Adenosine Receptor: Optimization, Structure-Activity Relationship Studies, and Enantiospecific Recognition

We present and thoroughly characterize a large collection of 3,4-dihydropyrimidin-2(1H)-ones as A(2B)AR antagonists, an emerging strategy in cancer (immuno) therapy. Most compounds selectively bind A(2B)AR, with a number of potent and selective antagonists further confirmed by functional cyclic adenosine monophosphate experiments. The series was analyzed with one of the most exhaustive free energy perturbation studies on a GPCR, obtaining an accurate model of the structure-activity relationship of this chemotype. The stereospecific binding modeled for this scaffold was confirmed by resolving the two most potent ligands [(+)-47, and (+/-)-38 K-i = 10.20 and 23.6 nM, respectively] into their two enantiomers, isolating the affinity on the corresponding (S)-eutomers (K-i = 6.30 and 11.10 nM, respectively). The assessment of the effect in representative cytochromes (CYP3A4 and CYP2D6) demonstrated insignificant inhibitory activity, while in vitro experiments in three prostate cancer cells demonstrated that this pair of compounds exhibits a pronounced antimetastatic effect.

Automated summary

The study presents and thoroughly characterizes a large collection of 3,4-dihydropyrimidin-2(1H)-ones as A(2B)AR antagonists, demonstrating their importance in cancer therapy. Through functional experiments and free energy perturbation studies, the structure-activity relationship of this chemotype was accurately modeled, with stereospecific binding confirmed by resolving the two most potent ligands into their enantiomers. Additionally, in vitro experiments showed significant antimetastatic effects of this pair of compounds in three prostate cancer cells.