在临床前小鼠模型中，使用双标记抗体靶向ETA受体的术前PET成像和人类胶质母细胞瘤的荧光引导手术：一种溶液方法

基本原理：胶质母细胞瘤（GBM）由于其异质性和侵入性而对完全清除肿瘤提出了重大挑战，强调需要有效的治疗选择。在过去的二十年中，采用荧光下的荧光引导手术（FGS），例如5-氨基乙酸（5-ALA）来增强肿瘤描述，在神经外科医生中吸引了吸引力。但是，一些低级肿瘤没有显示出示踪剂的任何积累，并且缺乏患者分层是一个重要的局限性。自2000年以来，内皮素轴已被广泛研究其在癌症进展中的作用。更具体地说，我们的团队已经确定了在胶质母细胞瘤干细胞中过表达的内皮素A受体（ETA），这是GBM成像感兴趣的目标。这项研究旨在评估新型的临床前双峰成像剂[89ZR] Zr-axira63-momip，作为一种疗法方法：i）在人类GBM的正常模型中检测ETA +细胞，II）ii）实现了完全肿瘤切除。方法：单分子多模式成像平台（MOMIP） - 含有荧光团（IRDYE800CW）和用于正电子发射放射体的螯合剂（Desferroxamine B，DFO） - 与Axira63抗体靶向ETA受体ETA受体相连。注射[89ZR] ZR-AXIRA63-MOMIP通过正电子发射断层扫描（PET）和光学成像后，对带有原位的人GBM的小鼠成像48小时。随后，在具有切除或未分离的肿瘤的大脑上，实施了验尸后FGS以及离体分析（H＆E染色，放射自显影，连续块面成像），以评估PET和荧光信号之间的相关性。结果：[89ZR] ZR-AXIRA63-MOMIP的PET成像在人类GBM的原位模型中可以清楚地检测到ETA +细胞。术中光学成像允许在长时间暴露时间后的弱荧光信号以及弱荧光信号的可视化，这是由于H＆E染色归因于残留的肿瘤细胞。此外，观察到两种方式的信号之间的定性相关性。结论：[89ZR] ZR-AXIRA63-MOMIP的使用提供了一种有效的疗法方法，可在临床前小鼠模型中通过手术来检测和治疗GBM。由于PET和荧光信号之间的高相关性允许患者分层，因此该双峰剂应具有巨大的临床翻译潜力，并且应该比已经在临床中使用的非靶向荧光团具有显着优势。

Rationale: Glioblastoma (GBM) poses significant challenges regarding complete tumor removal due to its heterogeneity and invasiveness, emphasizing the need for effective therapeutic options. In the last two decades, fluorescence-guided surgery (FGS), employing fluorophores such as 5-aminolevulinic acid (5-ALA) to enhance tumor delineation, has gained attraction among neurosurgeons. However, some low-grade tumors do not show any accumulation of the tracers, and the lack of patient stratification represents an important limitation. Since 2000, endothelin axis has been extensively investigated for its role in cancer progression. More specifically, our team has identified endothelin A receptors (ETA), overexpressed in glioblastoma cancer stem cells, as a target of interest for GBM imaging. This study aims to evaluate the efficacy of a novel preclinical bimodal imaging agent, [89Zr]Zr-axiRA63-MOMIP, as a theranostic approach to: i) detect ETA + cells in an orthotopic model of human GBM, ii) achieve complete tumoral resection. Methods: Monomolecular multimodal imaging platform (MOMIP) - containing both a fluorophore (IRDye800CW) and a chelator for a positron-emitting radiometal (desferroxamine B, DFO) - was conjugated to the axiRA63 antibody targeting ETA receptors, overexpressed on the surface of GBM stem cells. Mice bearing orthotopic human GBM were imaged 48 h post injection of [89Zr]Zr-axiRA63-MOMIP via positron emission tomography (PET) and optical imaging. Subsequently, post-mortem proof-of-concept FGS was implemented as well as ex vivo analyses (H&E staining, autoradiography, serial block face imaging) on brains with resected or unresected tumor to assess the correlation between PET and fluorescence signals. Results: PET imaging of [89Zr]Zr-axiRA63-MOMIP enabled a clear detection of ETA + cells in an orthotopic model of human GBM. Intraoperative optical imaging allowed a near-complete tumor resection together with the visualization of a weak fluorescence signal, after a prolonged exposure time, that was attributed to residual tumor cells via H&E staining. Besides, a qualitative correlation between the signals of both modalities was observed. Conclusions: The use of [89Zr]Zr-axiRA63-MOMIP provides an effective theranostic approach to detect and treat GBM by surgery in a preclinical mouse model. Thanks to the high correlation between PET and fluorescence signal allowing patients stratification, this bimodal agent should have a great potential for clinical translation and should present a significant advantage over non-targeted fluorophores already used in the clinic.