In Vivo Small-Animal PET/CT of EphB4 Receptors Using 64Cu-Labeled Peptide
In Vivo Small-Animal PET/CT of EphB4 Receptors Using 64Cu-Labeled Peptide
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使用 64Cu 标记肽对 EphB4 受体进行体内小动物 PET/CT
DOI：
10.2967/jnumed.110.081943
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发表时间：
2011-02-01
影响因子：
9.3
通讯作者：
Li, Chun
中科院分区：
文献类型：
--
作者：
Xiong, Chiyi;Huang, Miao;Li, Chun
许多实体瘤过表达EphB 4受体，Ephrin受体酪氨酸激酶家族的成员。EphB 4的非侵入性成像可能会提高早期检测率，监测对针对EphB 4的治疗的反应，并改善患者的预后。本研究的目的是评估一种新的Cu-64标记的肽，其对EphB 4受体的PET具有高受体结合亲和力。方法：用异硫氰酸荧光素（FITC）和DOTA标记EphB 4结合肽TNYLFSPNGPIARAW（TNYL-RAW）。DOTA-TNYL-RAW用Cu-64标记，具有高标记效率。使用表面等离子体共振技术测定TNYL-RAW及其衍生物与纯化的重组EphB 4的结合亲和力。通过荧光显微镜和放射性计数方法评估FITC-TNYL-RAW和Cu-64-DOTA-TNYL-RAW与癌细胞的体外结合。在携带表达EphB 4的CT 26和PC-3 M肿瘤以及EphB 4阴性A549肿瘤的小鼠中进行体内生物分布和小动物PET/CT。结果：TNYL-RAW及其衍生物对EphB 4具有较高的亲和力，平衡解离常数为1.98 ~ 23 nM。在体外，FITC-TNYL-RAW和Cu-64-DOTA-TNYL-RAW均被CT 26和PC-3 M细胞选择性摄取，但不被A549细胞摄取。FITC-TNYL-RAW和（64）CuDOTA-TNYL-RAW与CT 26和PC-3 M细胞的结合可被过量的TNYL-RAW阻断。在体内，Cu-64-DOTA-TNYLRAW在PC-3 M肿瘤中的摄取显著高于A549肿瘤，在放射性示踪剂注射后24小时，每克肿瘤的注射剂量百分比分别为0.84 +/- 0.09和0.44 +/- 0.09。小动物PET/CT清楚地显示了Cu-64-DOTA-TNYL-RAW在CT 26和PC-3 M肿瘤中的沉积，但在A549肿瘤中没有。此外，CT 26和PC-3 M肿瘤中的（64）CuDOTA-TNYL-RAW的摄取可被冷的TNYL-RAW阻断。结论：使用Cu-64-DOTA-TNYL-RAW，可以通过小动物PET/CT无创地检测EphB 4受体的表达。
Many solid tumors overexpress EphB4 receptor, a member of the ephrin receptor tyrosine kinase family. Noninvasive imaging of EphB4 could potentially increase early detection rates, monitor response to therapy directed against EphB4, and improve patient outcomes. The purpose of this study was to evaluate a novel Cu-64-labeled peptide with high receptor binding affinity for PET of EphB4 receptors. Methods: The EphB4-binding peptide TNYLFSPNGPIARAW (TNYL-RAW) was conjugated with fluorescein isothiocyanate (FITC) and DOTA. DOTA-TNYL-RAW was labeled with Cu-64 with high labeling efficiency. The binding affinity of TNYL-RAW and its derivatives to purified recombinant EphB4 was determined using surface plasmon resonance technology. In vitro binding of both FITC-TNYL-RAW and Cu-64-DOTA-TNYL-RAW to cancer cells was assessed by fluorescent microscopy and a radioactivity count method. In vivo biodistribution and small-animal PET/CT were performed in mice bearing EphB4-expressing CT26 and PC-3M tumors as well as EphB4-negative A549 tumors. Results: TNYL-RAW and its derivatives displayed high binding affinity to EphB4, with equilibrium dissociation constant of 1.98-23 nM. In vitro, both FITC-TNYL-RAW and Cu-64-DOTA-TNYL-RAW were selectively taken up by CT26 and PC-3M cells but not by A549 cells. Binding of FITC-TNYL-RAW and (64)CuDOTA-TNYL-RAW to CT26 and PC-3M cells could be blocked by an excess amount of TNYL-RAW. In vivo, Cu-64-DOTA-TNYLRAW showed significantly higher uptake in PC-3M tumors than in A549 tumors, with percentages of injected dose per gram of tumor of 0.84 +/- 0.09 and 0.44 +/- 0.09 at 24 h after radiotracer injection, respectively. Small-animal PET/CT clearly revealed deposition of Cu-64-DOTA-TNYL-RAW in CT26 and PC-3M tumors but not in A549 tumors. Furthermore, uptake of (64)CuDOTA-TNYL-RAW in both CT26 and PC-3M tumors could be blocked by cold TNYL-RAW. Conclusion: The expression of EphB4 receptors can be noninvasively interrogated by small-animal PET/CT using Cu-64-DOTA-TNYL-RAW.