Neuropilin‐1 (NRP‐1) is overexpressed in several kinds of cancer cell and contributes to tumor aggressiveness. Recently, the arginine/lysine‐rich peptide with C‐terminal motifs (R/K)XX(R/K) indicated promising penetrating and transporting capability into NRP‐1 positive cancer cells. In the present study, we describe a ¹³¹I‐labeled C‐end rule motif peptide conjugate, Tyr–tLyp‐1, for NRP‐1 positive tumor targeting and imaging properties. Briefly, a truncated Lyp‐1 peptide was designed to expose its C‐end motif and conjugated to tyrosine for radiolabeling after structural modification. The peptide indicated specific binding to A549 cancer cells at 2 μM concentration, and its binding was dependent on NRP‐1 expression and could be inhibited by other NRP‐1‐binding peptides. In vivo imaging of ¹³¹I‐labeled Tyr–tLyp‐1peptide showed that a subcutaneous A549 xenograft tumor could be visualized using a SPECT/CT scanner. The tumor uptake of ¹³¹I‐Tyr–tLyp‐1 was 4.77 times higher than the uptake in muscles by SPECT/CT software quantification at 6 h post injection. Together, this study indicated that truncated Lyp‐1 peptide could specifically localize in NRP‐1 positive tumors and successfully mediate the ¹³¹I radionuclide diagnosis, indicating promising targeted imaging capability for NRP‐1 positive tumors. Copyright © 2016 John Wiley & Sons, Ltd.

中文翻译：

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131I标记的神经纤维蛋白结合肽在靶向肿瘤成像中的生物分布和评估

Neuropilin-1（NRP-1）在几种类型的癌细胞中过表达，并有助于肿瘤的侵袭性。最近，具有C端基序（R / K）XX（R / K）的富含精氨酸/赖氨酸的肽表明其在NRP-1阳性癌细胞中具有良好的穿透和转运能力。在本研究中，我们描述了¹³¹ I标记的C末端规则基序肽偶联物Tyr–tLyp-1，用于NRP-1阳性肿瘤靶向和成像特性。简而言之，设计了截短的Lyp-1肽以暴露其C末端基序，并与酪氨酸偶联以进行结构修饰后的放射性标记。该肽以2μM的浓度显示出与A549癌细胞的特异性结合，其结合取决于NRP-1的表达，并可能被其他NRP-1结合的肽抑制。体内的成像¹³¹ I标记的酪氨酸- tLyp-1peptide表明，皮下A549异种移植肿瘤可以使用SPECT / CT扫描器来可视化。通过注射后6 h SPECT / CT软件定量，对¹³¹ I-Tyr-tLyp-1的肿瘤摄取比肌肉摄取高4.77倍。总之，这项研究表明，截短的Lyp-1肽可以特异性定位在NRP-1阳性肿瘤中，并成功介导¹³¹ I放射性核素的诊断，表明对NRP-1阳性肿瘤的靶向成像能力很有希望。版权所有©2016 John Wiley＆Sons，Ltd.