MAGIC - Magnetic Resonance Assessment of Gene Imaging Constructs

MAGIC - 基因成像构建体的磁共振评估

• 批准号: 7211047
• 负责人: RALPH P. MASON
• 金额: $ 15.7万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7211047
• 关键词: Acidity; Applications Grants; Biochemical; Biodistribution; Biological; Blood Vessels; Brain; Cells; Characteristics; Clinical Trials; Color; Contrast Media; Cytosine deaminase; Detection; Development; Endopeptidases; Enzymes; Evaluation; Flucytosine; Foundations; Future; Galactose; Galactosidase; Gene Expression; Genes; Heterogeneity; Histology; Image; Immune; Implant; Individual; Infusion procedures; Investigation; Ions; Iron; LacZ Genes; Life; Magic; Magnetic Resonance; Magnetic Resonance Imaging; Mammary gland; Marketing; Methods; Modality; Modification; Mus; Necrosis; Oncogenes; Optical Methods; Optics; Peptide Hydrolases; Polymerase Chain Reaction; Predisposition; Prodrugs; Property; Prostatic Neoplasms; Protons; Radioisotopes; Reaction; Reporter; Reporter Genes; Research; Research Project Grants; Resolution; Reverse Transcriptase Polymerase Chain Reaction; Risk; Site; System; Techniques; Technology; Testing; Thymidine Kinase; Time; Tissues; Toxic effect; Transgenes; Translating; Translations; Viral; Viral Load result; Western Blotting; analog; base; biomaterial compatibility; cancer therapy; concept; density; design; gene therapy; improved; in vivo; lipophilicity; neoplastic cell; novel; novel strategies; promoter; response; size; therapeutic gene; tool; tumor; tumor growth; water solubility

DESCRIPTION (provided by applicant): We will develop a novel approach to detecting transgene activity in tumors based on proton MRI of enzyme activated reporter molecules. Specifically, we will synthesize, evaluate, optimize, and apply novel agents to detect (3-galactosidase activity generated by the lacZ gene. Gene therapy holds great promise for treatment of cancer. However, major problems involve assessing delivery to target tissue, the uniformity (versus heterogeneity) of bio distribution and determining whether the genes are expressed. We propose a novel approach for evaluating gene expression using MRI. This research draws on foundations in optical detection of reporter genes, specifically P- galactosidase from the lacZ gene. Recently, 3,4-cyclohexenoesculetin-p-galactopyranoside, marketed commercially as S-Gal(tm), has been shown to generate an intense black color as a precipitate upon activation by p-gal in the presence of Fe3+ ions. This prompted us to consider the paramagnetic properties of the precipitate as a potential 1H MRI contrast agent. Preliminary studies have demonstrated feasibility and we now wish to translate and develop the concept to tumor cells for detection in vivo. Specific aim 1 will explore the utility of S-gal, with investigations to optimize and validate the technique. MRI parameters will be varied to maximize contrast with appropriate spatial and temporal resolution. Agent administration will be evaluated to maximize contrast and minimize toxicity. Specific aim 2 will focus on translation to tumors in living mice. MRI will be validated by comparison with optical methods in vivo and traditional methods such as histology and RT-PCR. Specific aim 3 focuses on the synthesis and development of alternate optimized substrates. We believe this approach can both become a valuable tool for detecting p-gal activity in vivo and serve as a proof of principle for a novel platform technology adaptable to other reporter genes and endogenous enzymes such as proteases.

描述（由申请人提供）：我们将开发一种基于酶激活报告分子的质子MRI检测肿瘤中转基因活性的新方法。具体来说，我们将合成、评估、优化和应用新的试剂来检测lacZ基因产生的(3-半乳糖苷酶活性。基因疗法对治疗癌症大有希望。然而，主要的问题包括评估递送到目标组织，生物分布的均匀性（相对于异质性）和确定基因是否表达。我们提出了一种利用MRI评估基因表达的新方法。本研究利用光学检测报告基因的基础，特别是来自lacZ基因的P-半乳糖苷酶。最近，在商业上以S-Gal（tm）的形式销售的3,4-环己烯esculetin-p-半乳糖苷，在Fe3+离子存在下被p-gal激活后，作为沉淀产生强烈的黑色。这促使我们考虑将沉淀物的顺磁性作为潜在的1H MRI造影剂。初步的研究已经证明了可行性，我们现在希望将这一概念转化并发展到肿瘤细胞中进行体内检测。具体目标1将探索S-gal的效用，通过调查来优化和验证该技术。MRI参数将改变，以最大限度地提高对比度，适当的空间和时间分辨率。将评估药物的给药，以最大限度地提高对比和减少毒性。具体目标2将集中在活体小鼠肿瘤的翻译。MRI将通过与活体光学方法和传统方法（如组织学和RT-PCR）的比较来验证。具体目标3侧重于替代优化底物的合成和开发。我们相信这种方法既可以成为检测体内p-gal活性的有价值的工具，也可以作为一种适用于其他报告基因和内源性酶（如蛋白酶）的新型平台技术的原理证明。