Nanoconjugates for Imaging in vivo Gene Expression in Medulloblastoma

描述（由申请人提供）：髓母细胞瘤是儿童原发性脑肿瘤，很难早期发现，也很难在术后重新评估复发和转移。该项目将测试一种生物学工具，用于非侵入性定量表达JC病毒癌蛋白（T抗原）的细胞中的基因表达，该蛋白与髓母细胞瘤相关。该工具是一种纳米缀合物，将具有用于MRI检测的超顺磁性氧化铁核心，并且作为概念证明，将靶向T抗原转化的癌细胞中的T抗原。识别JC病毒T抗原的抗体片段将用于识别出现在肿瘤细胞上的细胞表面抗原以用于靶向。MR成像将用于在体内追踪纳米缀合物。将进行研究，以表征和定量肿瘤细胞在体外和动物模型中的摄取。将使用组织学和放射性核素研究将纳米缀合物运输至细胞与MR图像相关联。该平台将用作概念验证，以快速有效地证明纳米缀合物能够选择性地归巢至表达T抗原的肿瘤细胞而不是正常细胞。该项目将使我们能够优化纳米颗粒的组成，确定纳米颗粒对T抗原的特异性，定量每个细胞的颗粒摄取，并优化体外和体内的MRI参数。该策略将能够确定哪些肿瘤表达T抗原，定量分析T抗原表达水平，并通过MRI和图像后处理分析非侵入性地监测对治疗性治疗的反应。然后，该技术可以针对癌症的其他高度表达的细胞内或病毒分子靶标进行修改。此外，在该提议中使用和开发的从靶特异性造影剂的合成到成像和图像分析技术的综合方法可用于转化为人类肿瘤的临床成像，并可能转化为靶向治疗的载体。 公共卫生相关声明：目前的建议旨在开发一种新的分子为基础的造影剂，将专门针对髓母细胞瘤肿瘤细胞。该试剂将改善脑肿瘤的诊断，并提供非侵入性监测脑肿瘤治疗反应的新方法。

DESCRIPTION (provided by applicant): Medulloblastoma, the primary brain tumor in children, is difficult to detect early and to reassess post-surgery with respect to recurrence and metastasis. This project will test a biological tool for non-invasive quantitation of gene expression in cells expressing the JC virus oncoprotein, T-antigen, which has been associated with medulloblastoma. The tool, a nanoconjugate, will have a core of superparamagnetic iron oxide for detection by MRI and, as proof of concept, will target T-antigen in T-antigen transformed cancer cells. An antibody fragment which recognizes JC virus T-antigen will be used to recognize cell-surface antigens appearing on tumor cells for targeting. MR imaging will be used to track the nanoconjugate in vivo. Studies will be done to characterize and quantify the uptake by tumor cells in vitro and in an animal model. Histopathology and radionuclide studies will be used to correlate the nanoconjugate trafficking to cells with the MR images. This platform will be used as a proof of concept to rapidly and effectively demonstrate that the nanoconjugate is able to selectively home to T-antigen expressing tumor cells but not normal cells. This project will allow us to optimize composition of the nanoparticle, determine specificity of the nanoparticle for T-antigen, quantitate particle uptake per cell, and optimize MRI parameters in vitro and in vivo. This strategy will enable determination of which tumors express T-antigen, quantitative analysis of the level of T-antigen expression, and monitoring of response to therapeutic treatment non-invasively through MRI and image post-process analysis. This technology may then be modified for other highly expressed intracellular or viral molecular targets of cancer. Furthermore the comprehensive methodology used and developed in this proposal from synthesis of the target-specific contrast agent to imaging and image analysis techniques may be used for translation into clinical imaging of human tumors and potentially into a vehicle for targeted therapy. PUBLIC HEALTH RELEVANCE STATEMENT: The current proposal seeks to develop a novel molecular based contrast agent which will specifically target medulloblastoma tumor cells. This agent would improve diagnosis of brain tumors and provide novel methods to non-invasively monitor response to brain tumor treatment.