Laboratory of Molecular Imaging and Nanomedicine (LOMIN), National Institute of Biomedical Imaging and Bioengineering (NIBIB), National Institutes of Health (NIH), Bethesda, Maryland, USA.
Bioconjug Chem. 2011 Mar 16;22(3):422-8. doi: 10.1021/bc100437q. Epub 2011 Feb 21.
Labeling biomolecules with ¹⁸F is usually done through coupling with prosthetic groups, which requires several time-consuming radiosynthesis steps and therefore in low labeling yield. In this study, we designed a simple one-step ¹⁸F-labeling strategy to replace the conventional complex and the long process of multiple-step radiolabeling procedure. Both monomeric and dimeric cyclic RGD peptides were modified to contain 4-NO₂-3-CF₃ arene as precursors for direct ¹⁸F labeling. Binding of the two functionalized peptides to integrin α(v)β₃ was tested in vitro using the MDA-MB-435 human breast cell line. The most promising functionalized peptide, the dimeric cyclic RGD, was further evaluated in vivo in an orthotopic MDA-MB-435 tumor xenograft model. The use of relatively low amount of precursor (~0.5 μmol) gave reasonable yield, ranging from 7 to 23% (decay corrected, calculated from the start of synthesis) after HPLC purification. Overall reaction time was 40 min, and the specific activity of the labeled peptide was high. Modification of RGD peptides did not significantly change the biological binding affinities of the modified peptides. Small animal PET and biodistribution studies revealed integrin specific tumor uptake and favorable biokinetics. We have developed a novel one-step ¹⁸F radiolabeling strategy for peptides that contain a specific arene group, which shortens reaction time and labor significantly, requires low amount of precursor, and results in specific activity of 79 ± 13 GBq/μmol. Successful introduction of 4-fluoro-3-trifluoromethylbenzamide into RGD peptides may be a general strategy applicable to other biologically active peptides and proteins.
标记生物分子通常是通过与前体基团偶联来完成的，这需要几个耗时的放射合成步骤，因此标记产率较低。在这项研究中，我们设计了一种简单的一步 ¹⁸F 标记策略，以取代传统的复杂和多步放射性标记过程。单体和二聚体环状 RGD 肽都被修饰为含有 4-NO₂-3-CF₃ 芳烃作为直接 ¹⁸F 标记的前体。使用 MDA-MB-435 人乳腺癌细胞系体外测试了两种功能化肽与整合素 α(v)β₃ 的结合。最有前途的功能化肽，二聚体环状 RGD，进一步在 MDA-MB-435 原位肿瘤异种移植模型中进行了体内评估。使用相对少量的前体（约 0.5 μmol），经 HPLC 纯化后，产率合理，范围为 7-23%（从合成开始时的衰变校正计算）。总反应时间为 40 分钟，标记肽的比活度高。RGD 肽的修饰并未显著改变修饰肽的生物学结合亲和力。小动物 PET 和生物分布研究显示整合素特异性肿瘤摄取和良好的生物动力学。我们开发了一种新型的一步 ¹⁸F 放射性标记策略，用于含有特定芳烃基团的肽，该策略大大缩短了反应时间和劳动强度，所需前体用量低，比活度为 79±13GBq/μmol。4-氟-3-三氟甲基苯甲酰胺成功引入 RGD 肽可能是一种适用于其他生物活性肽和蛋白质的通用策略。
