(S)-3-(Carboxyformamido)-2-(3-(carboxymethyl)ureido)propanoic Acid as a Novel PSMA Targeting Scaffold for Prostate Cancer Imaging

In an effort to seek novel agents targeting prostate-specific membrane antigen (PSMA), 16 ligands (L1–L16) with structural modifications in S1′ binding pocket were synthesized and evaluated for PSMA inhibition. (S)-3-(Carboxyformamido)-2-(3-(carboxymethyl)ureido)propanoic acids proved to be potent PSMA ligands with Ki values ranging from 0.08 nM to 8.98 nM, which are in the range of or are higher in potency compared to previously published urea-based ligands. Computational docking was performed to study the binding mode of the two most potent ligands discovered. FITC-conjugated L14 could selectively stain PSMA+ LNCaP cells over PSMA– PC3 cells. IRDye800CW conjugated L16 can effectively image tumors in a murine xenograft model of prostate cancer.