Synthesis and Binding of a Novel PSMA-specific Conjugate

Prostate-specific membrane antigen (PSMA) is emerging as a target for treatment of castration-resistant prostate cancer (CRPC) while its up-regulated in the majority of CRPC tumors. The most common approach is targeted radionuclide therapy.The PSMA binding pharmacophore Glu-Urea-Lysine (GUL) and lysine were conjugated to oxidized dextran with reductive amination and subsequently labelled with fluorosceinisothiocyanate (FITC). Three prostate cancer cell lines were used for binding studies, 22Rv1 (PSMA positive), DU145 (PSMA negative) and PC3 (PSMA negative). Binding images were obtained by fluorescence microscopy.PDC binding was recorded on the 22Rv1 cell line while the negative cell lines showed no or slight background binding. PDC binding could be inhibited by pre-incubation with a molar excess of unlabelled PDC.This is a novel template for PSMA targeted CRPC therapy, either using cytostatics or radionuclides.