癌胚抗原蛋白Melanoma antigen A3（MAGE-A3）在多种恶性肿瘤形式中高度表达。已经确认亲和体分子，一种新型的小型（约6.5 kDa）靶向蛋白家族，可作为分子成像和靶向肿瘤治疗的有用工具。本研究评估了亲和体分子作为MAGE-A3阳性肿瘤体内分子成像检测的新型药物的疗效。在这项研究中，经过三个循环的噬菌体展示文库筛选，分离出了两种新的亲和体分子（ZMAGE-A3:172和ZMAGE-A3:770），它们能够与MAGE-A3结合。这些分子然后在细菌中表达和纯化。使用Western blotting、免疫组织化学、间接免疫荧光、表面等离子共振和近红外光成像对具有高亲和力和特异性的亲和体分子进行评估并检测裸鼠肿瘤。所选的ZMAGE-A3亲和体分子可以在活细胞中与MAGE-A3蛋白精确结合，并在分子水平上显示高亲和力结合MAGE-A3蛋白。此外，DyLight755标记的ZMAGE-A3:172或ZMAGE-A3:770在MAGE-A3阳性肿瘤中的积累可在注射后30分钟即可达到，并在48小时后消失。我们的发现支持这两种MAGE-A3蛋白结合的亲和体分子作为分子成像药物的潜力。 版权所有 © 2023 Elsevier Inc. 发布

The cancer-testis protein melanoma antigen A3 (MAGE-A3) is highly expressed in a broad range of malignant tumor forms. It has been confirmed that affibody molecules, a novel family of small (∼6.5 kDa) targeting proteins, are useful agents for molecular imaging and targeted tumor treatment. As a novel agent for in vivo molecular imaging detection of MAGE-A3-positive tumors, the efficacy of affibody molecules was assessed in this research.In this study, three cycles of phage display library screening resulted in the isolation of two new affibody molecules (ZMAGE-A3:172 and ZMAGE-A3:770) that attach to MAGE-A3. These molecules were then expressed in bacteria and purified. The affibody molecules with high affinity and specificity were evaluated using western blotting, immunohistochemistry, indirect immunofluorescence, surface plasmon resonance, and near-infrared optical imaging of tumor-bearing nude mice.The selected ZMAGE-A3 affibodies can precisely bind to the MAGE-A3 protein in living cells and display high-affinity binding to the MAGE-A3 protein at the molecular level. Furthermore, the accumulation of DyLight755-labeled ZMAGE-A3:172 or ZMAGE-A3:770 in MAGE-A3-positive tumors was achieved as early as 30 min and disappeared at 48 h post-injection.Our findings support the potential of the two MAGE-A3 protein-binding affibody molecules for their use as molecular imaging agents.Copyright © 2023. Published by Elsevier Inc.