Hsieh Hsin-Hua, Kuo Wei-Ying, Lin Jia-Jia, Chen Hong-Sen, Hsu Hung-Ju, Wu Chun-Yi
Department of Biomedical Imaging and Radiological Sciences, National Yang Ming Chiao Tung University, Taipei Branch, Taipei 112, Taiwan.
Genomics Research Center, Academia Sinica, Taipei 115, Taiwan.
ACS Omega. 2022 Aug 23;7(35):31529-31537. doi: 10.1021/acsomega.2c04230. eCollection 2022 Sep 6.
Patients with prostate-specific membrane antigen (PSMA)-positive tumors can benefit from PSMA-targeted therapy; thus, we have constructed a phage-displayed synthetic antibody library for the production of novel PSMA antibodies with superior PSMA-targeting ability, favoring clinical management. The binding affinities of anti-PSMA antibodies were verified by an enzyme-linked immunosorbent assay (ELISA). Several in vitro and in vivo experiments, including cellular uptake, internalization, and cytotoxicity studies, micro single photon emission computed tomography (microSPECT)/CT, and biodistribution studies, were performed to select the most promising antibody among six different antibodies. The results showed the target affinities of our antibodies in the ELISA assays (7A, 8C, 8E, and 11A) were comparable to the existing antibodies (J591). The half-maximal effective concentrations of 7A, 8C, 8E, 11A, and J591 were 2.95, 6.64, 5.50, 2.08, and 4.79, respectively. The radiochemical yield of In-labeled antibodies ranged from 30% to 50% with high radiochemical purity (>90%). In the cellular uptake studies, the accumulated radioactivity of In-J591, In-7A, and In-11A increased over time. The internalized percentage of In-11A was the highest (32.14% ± 2.06%) at 48 h after incubation, whereas that of In-J591 peaked at 22.43% ± 4.38% at 24 h and dropped to 13.52% ± 3.03% at 48 h postincubation. Twenty-four hours after injection, radioactivity accumulation appeared in the LNCaP xenografts of the mice injected with In-11A, In-8E, In-7A, and In-J591 but not in the xenografts of the In-8C-injected group. Marked liver uptake was noticed in all groups except the In-11A-injected group. Moreover, the killing effect of Lu-11A was superior to that of Lu-J591 at low concentrations. In conclusion, we successfully demonstrated that 11A IgG owned the most optimal biological characteristics among several new anti-PSMA antibodies and it can be an excellent PSMA-targeting component for the clinical use.
前列腺特异性膜抗原（PSMA）阳性肿瘤患者可从PSMA靶向治疗中获益；因此，我们构建了一个噬菌体展示合成抗体文库，用于生产具有优异PSMA靶向能力的新型PSMA抗体，以利于临床管理。通过酶联免疫吸附测定（ELISA）验证抗PSMA抗体的结合亲和力。进行了多项体外和体内实验，包括细胞摄取、内化和细胞毒性研究、微型单光子发射计算机断层扫描（microSPECT）/CT以及生物分布研究，以从六种不同抗体中筛选出最有前景的抗体。结果显示，我们的抗体（7A、8C、8E和11A）在ELISA测定中的靶点亲和力与现有抗体（J591）相当。7A、8C、8E、11A和J591的半数有效浓度分别为2.95、6.64、5.50、2.08和4.79。铟标记抗体的放射化学产率在30%至50%之间，放射化学纯度高（>90%）。在细胞摄取研究中，铟-J591、铟-7A和铟-11A的累积放射性随时间增加。孵育48小时后，铟-11A的内化百分比最高（32.14%±2.06%），而铟-J591的内化百分比在孵育24小时时达到峰值22.43%±4.38%，在孵育48小时时降至13.52%±3.03%。注射24小时后，注射铟-11A、铟-8E、铟-7A和铟-J591的小鼠LNCaP异种移植瘤中出现放射性积聚，而注射铟-8C的组的异种移植瘤中未出现。除注射铟-11A的组外，所有组均观察到明显的肝脏摄取。此外，在低浓度下，镥-11A的杀伤效果优于镥-J591。总之，我们成功证明11A IgG在几种新型抗PSMA抗体中具有最理想的生物学特性，它可以成为临床应用中优异的PSMA靶向成分。
