Sodium lodide Symporter as an Imaging Reporter Gene

描述（由申请人提供）： Na+/I-同向转运体（NIS）是一种内源性膜糖蛋白，介导甲状腺滤泡细胞主动碘摄取。我们和其他人已经表明，NIS基因转移可以诱导碘摄取到各种细胞和异种移植表达外源性NIS可以在体内成像。这些数据表明，NIS的表达和功能，可以在体内定量测量NIS的摄取放射性碘的能力的基础上。因此，NIS可以用作成像报告基因（“Imagene”）以优化载体递送，监测治疗性基因表达，并定位体内再增殖祖细胞的组织/器官位点。拟议的项目旨在解决两个参数，是至关重要的有用性NIS作为一个Imagene：可接受的信噪比和条件，其中基因表达和测量的信号水平之间存在线性关系。我们假设这两个参数将根据靶细胞和体内宿主环境而变化。我们将确定NIS表达水平的相对重要性和不同信噪比组织中体内成像所需的NIS表达细胞的数量。确定了四个具体目标：目标1。确定与培养细胞中放射性碘积累相关的NIS表达水平的范围;目的2。确定皮下异种移植物中体内成像所需的NIS表达水平和NIS表达细胞的数量;目的3. 研究具有不同信噪比的内部器官中体内成像所需的不同NIS表达水平;以及目的4.评价NIS作为成像报告基因在临床前动物模型中监测治疗基因表达的可行性。拟议研究的成功将使我们能够使用NIS作为Imagene进行人体临床试验，以确保靶向和有效的基因转移，并在体内追踪重新增殖的祖细胞。

DESCRIPTION (provided by applicant): Na+/I- symporter (NIS) is an intrinsic membrane glycoprotein that mediates active iodide uptake into thyroid follicular cells. We and others have shown that NIS gene transfer can induce iodide uptake into a variety of cells and that xenografts expressing exogenous NIS could be imaged in vivo. These data suggest that NIS expression and function could be measured quantitatively in vivo based on NIS' ability to uptake radioiodide. Thus, NIS may serve as an imaging reporter gene ("lmagene") to optimize vector delivery, to monitor therapeutic gene expression, and to map the tissue/organ sites of repopulated progenitor cells in vivo. The proposed project aims to address the two parameters that are vital to the usefulness of NIS as an Imagene: acceptable signal-to-noise ratio and conditions in which a linear relationship exists between gene expression and measured signal levels. We hypothesize that these two parameters will vary, based upon target cells and in vivo host environment. We will determine the relative importance of NIS expression levels and the number of NIS expressing cells required for in vivo imaging in tissues of different signal to noise ratios. Four specific aims are identified: Aim 1. Determine the range of NIS expression levels that correlate with radioiodide accumulation in cultured cells; Aim 2. Determine the NIS expression levels and the number of NIS expressing cells required for in vivo imaging in subcutaneous xenografts; Aim 3. Investigate the different NIS expression levels required for in vivo imaging in internal organs with different signal to noise ratios; and Aim 4. Evaluate the feasibility of NIS as an imaging reporter gene to monitor therapeutic gene expression in a preclinical animal model. The success of the proposed studies will allow us to proceed to human clinical trials using NIS as an Imagene to ensure targeted and effective gene transfer and to track repopulated progenitor cells in vivo.