Deken Marion M, Bos Desirée L, Tummers Willemieke S F J, March Taryn L, van de Velde Cornelis J H, Rijpkema Mark, Vahrmeijer Alexander L
Department of Surgery, Leiden University Medical Center, Leiden, The Netherlands.
Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.
EJNMMI Res. 2019 Nov 21;9(1):98. doi: 10.1186/s13550-019-0564-z.
Combining modalities using dual-labeled antibodies may allow preoperative and intraoperative tumor localization and could be used in image-guided surgery to improve complete tumor resection. Trastuzumab is a monoclonal antibody against the human epidermal growth factor-2 (HER2) receptor and dual-labeled trastuzumab with both a fluorophore (IRDye800CW) and a radioactive label (In) can be used for multimodal imaging of HER2-positive breast cancer. The aim of this study was to demonstrate the feasibility of HER2-targeted multimodal imaging using [In]In-DTPA-trastuzumab-IRDye800CW in an orthotopic breast cancer model.
Trastuzumab was conjugated with p-isothiocyanatobenzyl (ITC)-diethylenetriaminepentaacetic acid (DTPA) and IRDye800CW-NHS ester and subsequently labeled with In. In a dose escalation study, the biodistribution of 10, 30, and 100 μg [In]In-DTPA-trastuzumab-IRDye800CW was determined 48 h after injection in BALB/c nude mice with orthotopic high HER2-expressing tumors. Also, a biodistribution study was performed in a low HER2-expressing breast cancer model. In addition, multimodal image-guided surgery was performed in each group. Autoradiography, fluorescence microscopy, and immunohistochemically stained slices of the tumors were compared for co-localization of tumor tissue, HER2 expression, fluorescence, and radiosignal.
Based on the biodistribution data, a 30 μg dose of dual-labeled trastuzumab (tumor-to-blood ratio 13 ± 2) was chosen for all subsequent studies. [In]In-DTPA-trastuzumab-IRDye800CW specifically accumulated in orthotopic HER2-positive BT474 tumors (101 ± 7 %IA/g), whereas uptake in orthotopic low HER2-expressing MCF7 tumor was significantly lower (1.2 ± 0.2 %IA/g, p = 0.007). BT474 tumors could clearly be visualized with both micro-SPECT/CT, fluorescence imaging and subsequently, image-guided resection was performed. Immunohistochemical analyses of BT474 tumors demonstrated correspondence in fluorescence, radiosignal, and high HER2 expression.
Dual-labeled trastuzumab showed specific accumulation in orthotopic HER2-positive BT474 breast tumors with micro-SPECT/CT and fluorescence imaging and enabled image-guided tumor resection. In the clinical setting, [In]In-DTPA-trastuzumab-IRDye800CW could be valuable for preoperative detection of (metastatic) tumors by SPECT/CT imaging, and intraoperative localization by using a gamma probe and fluorescence image-guided surgery to improve radical resection of tumor tissue in patients with HER2-positive tumors.
使用双标记抗体联合多种成像方式可实现术前及术中肿瘤定位，并可用于影像引导手术以提高肿瘤完整切除率。曲妥珠单抗是一种抗人表皮生长因子2（HER2）受体的单克隆抗体，带有荧光团（IRDye800CW）和放射性标记（铟[In]）的双标记曲妥珠单抗可用于HER2阳性乳腺癌的多模态成像。本研究的目的是在原位乳腺癌模型中证实使用[铟In]In-DTPA-曲妥珠单抗-IRDye800CW进行HER2靶向多模态成像的可行性。
将曲妥珠单抗与对异硫氰酸苄基（ITC）-二乙三胺五乙酸（DTPA）以及IRDye800CW-NHS酯偶联，随后用铟进行标记。在剂量递增研究中，给原位高表达HER2肿瘤的BALB/c裸鼠注射10、30和100μg[铟In]In-DTPA-曲妥珠单抗-IRDye800CW后48小时，测定其生物分布。此外，在低HER2表达的乳腺癌模型中进行了生物分布研究。另外，对每组进行了多模态影像引导手术。比较肿瘤组织的放射性自显影、荧光显微镜检查以及免疫组织化学染色切片，以确定肿瘤组织、HER2表达、荧光和放射信号的共定位情况。
基于生物分布数据，后续所有研究均选择30μg剂量的双标记曲妥珠单抗（肿瘤与血液比值为13±2）。[铟In]In-DTPA-曲妥珠单抗-IRDye800CW特异性积聚于原位HER2阳性的BT474肿瘤（101±7%IA/g），而原位低表达HER2的MCF7肿瘤摄取明显较低（1.2±0.2%IA/g，p = 0.007）。通过微型SPECT/CT、荧光成像均可清晰显示BT474肿瘤，随后进行了影像引导下的切除。对BT474肿瘤的免疫组织化学分析表明，荧光、放射信号与高HER2表达具有一致性。
双标记曲妥珠单抗在原位HER2阳性的BT474乳腺肿瘤中通过微型SPECT/CT和荧光成像显示出特异性积聚，并能够实现影像引导下的肿瘤切除。在临床环境中，[铟In]In-DTPA-曲妥珠单抗-IRDye800CW对于通过SPECT/CT成像进行（转移性）肿瘤的术前检测以及通过使用γ探针和荧光影像引导手术进行术中定位，以提高HER2阳性肿瘤患者肿瘤组织的根治性切除可能具有重要价值。
