Injectable reporters to image tumors and guide resection

描述（由申请人提供）：使用临床可转化的分子成像剂进行早期检测：将开发、优化和定量表征用于通过T1加权磁共振成像（MRI）或正电子发射断层扫描（PET）检测肿瘤的新型临床可转化的分子成像造影剂。MRI试剂是与带有钆螯合物的树枝状聚合物缀合的可活化细胞穿透肽（ACPP）。ACPP对基质金属蛋白酶的选择性和钆螯合物的稳定性将被优化。PET报告分子将是带有新型近红外（NIR）荧光团的缩小尺寸的抗体，其中包含18 F-氟硼酸盐。MRI和PET试剂将在小鼠肿瘤中进行测试，这些肿瘤稳定表达荧光（FL）、生物发光（BL）和正电子发射断层扫描（PET）的遗传报告基因，结合了远红荧光蛋白、萤火虫荧光素酶和胸苷激酶的最佳可用版本，表达为通过自切割病毒2A序列分离的单独但遗传连接的蛋白质。这些测试将量化这种可注射剂检测不同大小和进展阶段的实体瘤的可靠性，在什么情况下获得假阳性和阴性信号，探针和成像模式的组合何时上级另一种，以及是否可以区分惰性与高度恶性和侵袭性肿瘤。FL引导的手术切除和辅助治疗的评估和改进：将比较来自可注射剂的术中FL引导，例如ACPP与荧光树枝状聚合物缀合，用NIR荧光团标记的尺寸减小的抗体或5-氨基乙酰丙酸盐，与来自代表完美肿瘤特异性标记的荧光蛋白的FL引导。这些比较将显示哪种可注射剂在什么情况下表现最好，以及荧光引导切除的完整性是否更多地受到当前造影剂的不完善的生化特异性的限制，或者由于无法分辨和手动去除分散或播散的肿瘤细胞。还将测试光动力疗法（PDT）在闭合前杀死术野中残留的肿瘤细胞。初始肿瘤切除的完整性和任何复发将在术后使用遗传报告基因进行评估。与来自可注射造影剂和传统存活测量的信号的比较应该量化手术结果如何取决于肿瘤细胞去除的彻底性，当前可注射造影剂与基因完美标记相比的改善程度，PDT是否有帮助，当前可注射剂监测复发的效果如何，以及哪些材料或程序最需要改进。 公共卫生相关性：该项目旨在开发，优化和表征新型可注射，临床可翻译造影剂的性能，用于肿瘤的早期检测，区分惰性和侵袭性癌症，分子荧光引导手术和术后监测。长期目标是在侵袭性肿瘤仍然很小和局部化的时候提高对它们的检测，并帮助外科医生准确地完全切除这些肿瘤，同时尽可能多地保留正常组织。

DESCRIPTION (provided by applicant): Early detection with clinically translatable molecular imaging agents: Novel clinically translatable molecular imaging contrast agents for detecting tumors by T1-weighted magnetic resonance imaging (MRI) or positron emission tomography (PET) will be developed, optimized, and quantitatively characterized. The MRI agents are activatable cell penetrating peptides (ACPPs) conjugated to dendrimers bearing gadolinium chelates. The ACPPs' selectivity for matrix metalloproteinases and the stability of the gadolinium chelates will be optimized. The PET reporters will be reduced-size antibodies bearing novel near-infrared (NIR) fluorophores incorporating 18F-fluoborates. Both MRI and PET agents will be tested in mice on tumors stably expressing genetic reporters for fluorescence (FL), bioluminescence (BL), and positron emission tomography (PET), combining best available versions of far-red fluorescent protein, firefly luciferase, and thymidine kinase, expressed as separate but genetically linked proteins separated by self-cleaving viral 2A sequences. These tests will quantify how reliably can such injectable agents detect solid tumors of different sizes and stages of progression, under what circumstances false positive and negative signals are obtained, when is either combination of probe and imaging modality superior to the other, and whether indolent vs. highly malignant and invasive tumors can be distinguished. Evaluation and improvement of FL-guided surgical resection and adjuvant therapies: Intraoperative FL guidance from injectable agents such as ACPPs conjugated to fluorescent dendrimers, reduced-size antibodies labeled with NIR fluorophores, or 5-aminolevulinate will be compared with FL guidance from the fluorescent protein representing perfect tumor-specific labeling. These comparisons will show which injectable agent performs best under what circumstances, and whether completeness of fluorescence-guided resection is limited more by imperfect biochemical specificity of current contrast agents, or by inability to resolve and manually remove scattered or disseminated tumor cells. Photodynamic therapy (PDT) to kill off residual tumor cells in the surgical field before closure will also be tested. Completeness of initial tumor removal and any recurrence will be assessed postoperatively using the genetic reporters. Comparison with signals from injectable contrast agents and traditional survival measures should quantify how surgical outcomes depend on the thoroughness of tumor cell removal, how much improvement results from current injectable contrast agents vs. genetically perfectly labeling, whether PDT helps, how well can current injectable agents monitor recurrence, and what materials or procedures most need improvement. PUBLIC HEALTH RELEVANCE: This project aims to develop, optimize, and characterize the performance of novel injectable, clinically translatable contrast agents for early detection of tumors, distinction between indolent and aggressive cancers, molecular fluorescence-guided surgery, and postoperative monitoring. The long-term goal is to improve detection of aggressive tumors while they are still small and localized, and to help surgeons remove those tumors accurately completely while sparing as much normal tissue as possible.