FOLH1 and prostate cancer: In the present study, towards the targeting of these carbohydrate analogues to prostate cancer (PCa), we synthesized prodrugs in which a parent thiophene or butenolide congener was conjugated through a self-immolative linker to 2-[3-(1,3-dicarboxypropyl)ureido] pentanedioic acid (DUPA), a highly specific ligand for prostate-specific membrane antigen (PSMA), which is overexpressed on prostate tumors.