脂肪酸结合蛋白 3 (FABP3) 在肿瘤细胞和肿瘤脉管系统中表达，使其成为医学成像和治疗的潜在靶点。在本研究中，我们的目的是用游离氨基和硫醇基团对CooP肽进行放射性标记，并评估放射性标记产品[18F]FNA-N-CooP通过正电子发射断层扫描对乳腺癌脑转移中FABP3表达进行成像。 [18F]FNA-N-CooP 通过高度化学选择性的 N-酰化制备，并使用不同的化学方法进行表征。我们使用体外组织切片放射自显影验证了其与靶标的结合，并进行了体外和体内稳定性测试。 [18F]FNA-N-CooP 成功合成，经衰变校正的放射化学产率为 16.8%，放射化学纯度高（98.5%）。它在乳腺癌患者的脑转移组织切片上表现出异质结合，放射性结合灶对应于 FABP3 阳性。此外，在非放射性 FNA-N-CooP 阻断剂存在下，示踪剂结合减少了 55%，表明示踪剂特异性结合，并且 FABP3 是 [ 18 F]FNA-N-CooP 的可行靶标。有利的是，示踪剂不与坏死的肿瘤组织结合。然而，[18F]FNA-N-CooP 在小鼠血浆或人血清的体外以及小鼠体内的稳定性均有限，因此需要进一步的研究来提高 [18F]FNA-N-CooP 用于体内应用。

Fatty acid binding protein 3 (FABP3) is expressed both in tumor cells and in the tumor vasculature, making it a potential target for medical imaging and therapy. In this study, we aimed to radiolabel a CooP peptide with a free amino and thiol group, and evaluate the radiolabeled product [18F]FNA-N-CooP for imaging FABP3 expression in breast cancer brain metastases by positron emission tomography. [18F]FNA-N-CooP was prepared by highly chemoselective N-acylation and characterized using different chemical approaches. We validated its binding to the target using in vitro tissue section autoradiography and performed stability tests in vitro and in vivo. [18F]FNA-N-CooP was successfully synthesized in 16.8% decay-corrected radiochemical yield with high radiochemical purity (98.5%). It exhibited heterogeneous binding on brain metastasis tissue sections from a patient with breast cancer, with foci of radioactivity binding corresponding to FABP3 positivity. Furthermore, the tracer binding was reduced by 55% in the presence of nonradioactive FNA-N-CooP a blocker, indicating specific tracer binding and that FABP3 is a viable target for [18F]FNA-N-CooP. Favorably, the tracer did not bind to necrotic tumor tissue. However, [18F]FNA-N-CooP displayed limited stability both in vitro in mouse plasma or human serum and in vivo in mouse, therefore further studies are needed to improve the stability [18F]FNA-N-CooP to be used for in vivo applications.