Targeting CAIX with [Cu-64]XYIMSR-06 Small Molecular Radiotracer Enables Noninvasive PET Imaging of Malignant Glioma in U87 MG Tumor Cell Xenograft Mice
Targeting CAIX with [Cu-64]XYIMSR-06 Small Molecular Radiotracer Enables Noninvasive PET Imaging of Malignant Glioma in U87 MG Tumor Cell Xenograft Mice
复制标题
使用 [Cu-64]XYIMSR-06 小分子放射性示踪剂靶向 CAIX 可对 U87 MG 肿瘤细胞异种移植小鼠中的恶性胶质瘤进行无创 PET 成像
DOI：
10.1021/acs.molpharmaceut.8b01210
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发表时间：
2019
影响因子：
4.9
通讯作者：
Yang Zhi
中科院分区：
文献类型：
--
作者：
Yang Xianteng;Zhu Hua;Yang Xing;Li Nan;Huang Haifeng;Liu Teli;Guo Xiaoyi;Xu Xiaoxia;Xia Lei;Deng Chaoyong;Tian Xiaobin;Yang Zhi
碳酸酐酶IX（CAIX）在胶质瘤细胞增殖、侵袭、转移以及对放化疗的抵抗中起重要作用。一个有效的和非侵入性的PET分子显像剂靶向CAIX将有助于其诊断和治疗，但目前还没有。最近，据报道，低分子量（LMW）CAIX靶向剂[64Cu] XYIMSR-06具有显著改善的靶向透明细胞肾细胞癌（ccRCC）的性质。我们鼓励调查的可行性，适应这种代理CAIX过表达恶性胶质瘤的诊断和治疗。使用体外细胞摄取和结合亲和力测定来验证[64Cu] XYIMSR-06与U87 MG肿瘤细胞的结合能力，其中CAIX过表达被证实。建立U87 MG荷瘤小鼠（原位和皮下）模型，并将小鼠注射放射性示踪剂和/或与乙酰唑胺（0.2g/kg）共注射作为阻断剂用于无创性micro-PET成像。在注射后2、4和8 h进行Micro-PET成像。在原位神经胶质瘤肿瘤模型中进行基于ROI（感兴趣区域）的半定量。在注射后2、4、4 h阻滞、8和24 h进行各器官的生物分布。HE染色和免疫荧光或免疫组化（IF/IHC）染色观察肿瘤组织中CAIX的表达。在体外，[64Cu] XYIMSR-06在神经胶质瘤细胞（高CAIX表达）中比在HCT 116细胞（低CAIX表达）中表现出更大的摄取。[64Cu] XYIMSR-06与U87 MG细胞系的结合亲和力高达4.22 nM。原位和皮下肿瘤在注射后2 - 8小时清晰可见。生物分布研究表明，最大肿瘤摄取3.13%ID/g在4小时注射后，肿瘤与脑的比例（T/脑）是6.51在8小时注射后。基于ROI的T/脑值在注射后2和8 h分别为7.03和5.46。组织学分析证实了CAIX在胶质瘤中的过表达，并且CAIX阳性IF染色的区域与micro-PET成像上的形态极其一致。在这项研究中，[64Cu] XYIMSR-06在表达CAIX的U87 MG胶质瘤肿瘤中表现出特异性蓄积，表明放射性示踪剂具有非侵入性监测和指导恶性胶质瘤和其他过表达CAIX的肿瘤的个性化治疗的潜力。
Carbonic anhydrase IX (CAIX) plays an important role in glioma cell proliferation, invasion, metastasis, and resistance to radiotherapy and chemotherapy. An effective and noninvasive PET molecular imaging agent targeting CAIX would help its diagnosis and treatment but is not currently available. Recently, a low-molecular-weight (LMW) CAIX targeting agent, [64Cu]XYIMSR-06, was reported to have significantly improved properties for targeting clear cell renal cell carcinoma (ccRCC). We are encouraged to investigate the feasibility of adapting this agent for the diagnosis and treatment of CAIX-overexpressing malignant glioma. In vitro cell uptake and binding affinity assays were used to verify the binding capacity of [64Cu]XYIMSR-06 to U87 MG tumor cells in which CAIX overexpression was confirmed. The U87 MG tumor-bearing mouse (in situ and subcutaneous) model was built, and mice were injected with the radiotracer and/or coinjected with acetazolamide (0.2 g/kg) as a blocking agent for noninvasive micro-PET imaging. Micro-PET imaging was performed at 2, 4, and 8 h postinjection. ROI (region of interest)-based semiquantification was performed in an orthotopic glioma tumor model. Biodistribution throughout each organ was performed at 2, 4, 4 h block, 8, and 24 h postinjection. Hematoxylin and eosin (HE) staining and immunofluorescence or immunohistochemistry (IF/IHC) staining were implemented postimaging to assess the expression of CAIX in tumor organs. In vitro, [64Cu]XYIMSR-06 exhibits greater uptake in glioma cells (high CAIX expression) than in HCT116 cells (low CAIX expression). The binding affinity of [64Cu]XYIMSR-06 to U87 MG cell lines reaches up to 4.22 nM. Both orthotopic and subcutaneous tumors were clearly visualized at 2–8 h postinjection. Biodistribution studies demonstrated a maximum tumor uptake of 3.13% ID/g at 4 h postinjection, and the tumor to brain ratio (T/brain) was 6.51 at 8 h postinjection. The ROI-based T/brain values were 7.03 and 5.46 at 2 and 8 h postinjection, respectively. Histopathological analysis confirmed the overexpression of CAIX in gliomas, and the area of CAIX-positive IF staining is extremely consistent with the morphology on micro-PET imaging. In this study, [64Cu]XYIMSR-06 demonstrated specific accumulation in CAIX-expressing U87 MG glioma tumors, indicating that the radiotracer has the potential for noninvasively monitoring and guiding personalized treatment of malignant glioma and other tumors overexpressing CAIX.