Injectable reporters to image tumors and guide resection

描述（由申请人提供）：临床可翻译分子显像剂的早期检测：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翻译分子显像造影剂。MRI试剂是可活化的细胞穿透肽（ACPPs）偶联到带有钆螯合物的树状大分子。优化ACPPs对基质金属蛋白酶的选择性和钆螯合物的稳定性。PET报告将是缩小尺寸的抗体，含有含有18f -氟硼酸盐的新型近红外（NIR）荧光团。MRI和PET试剂将在小鼠肿瘤上进行测试，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，结合最佳版本的远红色荧光蛋白，萤火虫荧光素酶和胸苷激酶，表达为独立但遗传连接的蛋白，由自切割病毒2A序列分离。这些测试将量化此类注射剂检测不同大小和进展阶段的实体肿瘤的可靠性，在什么情况下获得假阳性和阴性信号，何时探头和成像方式的组合优于另一种，以及是否可以区分惰性肿瘤与高度恶性和侵袭性肿瘤。FL引导手术切除和辅助治疗的评价和改进：术中可注射药物的FL引导，如与荧光树状大分子缀合的ACPPs、用近红外荧光团标记的小尺寸抗体或5-氨基乙酰酸盐，将与代表完美肿瘤特异性标记的荧光蛋白的FL引导进行比较。这些比较将显示哪种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不完善的生化特异性的限制，或者无法分解和手动去除分散或播散的肿瘤细胞。光动力疗法（PDT）在手术结束前杀死手术野中残留的肿瘤细胞也将进行测试。术后将使用基因报告来评估初始肿瘤切除的完整性和任何复发。对比注射造影剂和传统生存测量的信号，可以量化手术结果如何取决于肿瘤细胞去除的彻彻性，目前注射造影剂与基因完美标记的改善程度，PDT是否有帮助，目前注射造影剂监测复发的效果如何，以及哪些材料或程序最需要改进。

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.