SPECT imaging with 99mTc-labeled EGFR-specific nanobody for in vivo monitoring of EGFR expression
SPECT imaging with 99mTc-labeled EGFR-specific nanobody for in vivo monitoring of EGFR expression
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DOI：
10.1007/s11307-008-0133-8
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发表时间：
2008-05-01
影响因子：
3.1
通讯作者：
Lahoutte, Tony
中科院分区：
文献类型：
--
作者：
Huang, Lieven;Gainkam, Lea Olive Tchouate;Lahoutte, Tony
目的：表皮生长因子受体（EGFR）的过度表达在多种肿瘤中发生率很高。受体的致癌表达已被用于基于免疫球蛋白的诊断和治疗。我们描述了一种美洲驼单域抗体片段，称为Nanobody（R），在体内使用单光子发射计算机断层扫描（SPECT）在小鼠中EGFR过表达肿瘤的放射免疫检测方法：进行荧光激活细胞分选（FACS）分析，以评估8B 6 Nanobody结合EGFR过表达细胞上EGFR的特异性和选择性。然后用Tc-99 m通过其C-末端组氨酸尾标记纳米抗体。通过离体分析评估正常器官和组织中的摄取。通过针孔SPECT在携带EGFR高（A431）或中度（DU 145）过表达的肿瘤细胞异种移植物的小鼠中评估Tc-99 m-8B 6纳米抗体的体内肿瘤靶向。Tc-99 m-8B 6纳米抗体的体内血液清除相对较快（半衰期，1.5小时），主要通过肾脏清除。注射后3 h，与肝脏总摄取（18.9 +/-0.6%IA）相比，肾脏总蓄积（46.6 +/-0.9%IA）较高。荷A431异种移植物小鼠的针孔SPECT成像显示，与DU 145异种移植物（1.8 ± 0.3%IA/cm（3），p <0.05）相比，Tc-99 m-8B 6纳米抗体的平均肿瘤摄取（5.2 ± 0.5%IA/cm（3））更高。
Purpose: Overexpression of the epidermal growth factor receptor (EGFR) occurs with high incidence in various carcinomas. The oncogenic expression of the receptor has been exploited for immunoglobulin-based diagnostics and therapeutics. We describe the use of a llama single-domain antibody fragment, termed Nanobody (R), for the in vivo radioimmunodetection of EGFR overexpressing tumors using single photon emission computed tomography (SPECT) in mice.Methods: Fluorescence-activated cell sorting (FACS) analysis was performed to evaluate the specificity and selectivity of 8B6 Nanobody to bind EGFR on EGFR overexpressing cells. The Nanobody was then labeled with Tc-99m via its C-terminal histidine tail. Uptake in normal organs and tissues was assessed by ex vivo analysis. In vivo tumor targeting of Tc-99m-8B6 Nanobody was evaluated via pinhole SPECT in mice bearing xenografts of tumor cells with either high (A431) or moderate (DU145) overexpression of EGFR.Results: FACS analysis indicated that the 8B6 Nanobody only recognizes cells overexpressing EGFR. In vivo blood clearance of Tc-99m-8B6 Nanobody is relatively fast (half-life, 1.5 h) and mainly via the kidneys. At 3 h postinjection, total kidney accumulation is high (46.6 +/- 0.9%IA) compared to total liver uptake (18.9 +/- 0.6%IA). Pinhole SPECT imaging of mice bearing A431 xenografts showed higher average tumor uptake (5.2+0.5%IA/cm(3)) of Tc-99m-8B6 Nanobody compared to DU145 xenografts (1.8+0.3%IA/cm(3), p