Preparation and Evaluation of Radiolabeled Antibody Recruiting Small Molecules That Target Prostate-Specific Membrane Antigen for Combined Radiotherapy and Immunotherapy

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• 作者：Afaf R. Genady ; Nancy Janzen ; Laura Banevicius ; Mahmoud El-Gamal ; Mohamed E. El-Zaria ; John F. Valliant
• 刊名：Journal of Medicinal Chemistry
• 出版年：2016
• 出版时间：March 24, 2016
• 年：2016
• 卷：59
• 期：6
• 页码：2660-2673
• 全文大小：631K
• ISSN：1520-4804

文摘

The feasibility of developing a single agent that can deliver radioactive iodine and also direct cellular immune function by engaging endogenous antibodies as an antibody-recruiting small molecule (ARM) was determined. A library of new prostate-specific membrane antigen (PSMA)-binding ligands that contained antibody-recruiting 2,4-dinitrophenyl (DNP) groups and iodine were synthesized and screened in vitro and in vivo. A lead compound (9b) showed high affinity for PSMA and the ability to bind anti-DNP antibodies. Biodistribution studies of the iodine-125 analogue showed 3% ID/g in LNCaP xenograft tumors at 1 h postinjection with tumor-to-blood and tumor-to-muscle ratios of 10:1 and 44:1, respectively. The radiolabeled analogue was bound and internalized by LNCaP cells, with both functions blocked using a known PSMA inhibitor. A second candidate showed high tumor uptake (>10% ID/g) but had minimal binding to anti-DNP antibodies. The compounds reported represent the first examples of small molecules developed specifically for combination immunotherapy and radiotherapy for prostate cancer.