Functional Imaging of Twist induced breast cancer

描述（由申请人提供）：了解肿瘤的侵袭和转移提供了关于癌症进展的重要信息。为了实现这一目标，我们已经确定了一种中胚层基因Twist，它在促进乳腺癌的形成中起着至关重要的作用。该实验室早期的研究结果表明，MCF-7乳腺癌细胞中Twist（一种基本的螺旋-环-螺旋转录因子）的过度表达促进了肿瘤的发生，并增加了异种移植物肿瘤微环境中的血管和通透性。初步研究表明，过表达该转录因子可促进与恶性转化和转移相关的标志物胆碱激酶的表达。此外，从这些转基因细胞中含有磷胆碱和总胆碱的化合物的升高水平可以明显看出胆碱激酶活性的增加。本研究旨在利用功能成像技术，了解Twist通过改变乳腺上皮细胞生理生化，促进乳腺癌侵袭转移的作用。三个具体目的是：1)通过功能磁共振成像和波谱技术鉴定Twist过表达乳腺癌细胞在原位肿瘤中的生化和生理变化；2)功能表征和成像下调Twist在乳腺癌异种移植模型中的作用；3)在Twist过表达细胞中鉴定新的转移标志物并在乳腺癌患者样本中验证它们。在本研究中，我们将使用功能磁共振成像技术来识别影响乳腺肿瘤表型特征的分子变化，如Twist过表达和Twist下调细胞中含胆碱化合物水平、乳酸水平、细胞外pHe、血管体积和通透性表面积产物的变化。此外，我们将使用非侵入性光学成像技术，利用转染了光学报告基因（tdTomato）的MCF-7/Twist细胞来识别癌症进展的各个阶段。最后，使用临床前模型确定的基因标记模式将应用于患者样本，以确定乳腺癌进展的潜在标记。从长远来看，这些研究将有助于乳腺癌的病理诊断，并为开发新的乳腺癌成像标志物和化疗药物提供见解。

DESCRIPTION (provided by applicant): Understanding tumor invasion and metastasis provides crucial information with respect to carcinoma progression. Towards this goal, we have identified a mesodermal gene, Twist, which has a crucial role in promoting breast cancer formation. Earlier results from this laboratory have indicated that over-expression of Twist, a basic helix-loop-helix transcription factor, in MCF-7 breast cancer cells promotes tumorigenesis and increased vasculature and permeability within the tumor microenvironment of xenografts. Preliminary data have indicated that over-expression of this transcription factor can promote the expression of the choline kinase, a marker related to malignant transformation and metastasis. In addition, the activity of the increased levels of choline kinase is evident from the elevated levels of phosphocholine and total choline containing compounds in these transgenic cells. The present proposal is designed to understand the role of Twist in promoting breast cancer invasion and metastasis by altering the cellular physiology and biochemistry of breast epithelium by using functional imaging techniques. The three specific aims are: 1) To identify biochemical and physiological alterations in orthotopic tumors using Twist over-expressing breast cancer cells by functional magnetic resonance imaging and spectroscopy, 2) To functionally characterize and image the effects of down- regulating Twist in breast cancer xenograft models, and 3) To identify novel metastatic markers in Twist over-expressing cells and to validate them in breast cancer patient samples. In this study, we will use functional magnetic resonance imaging to identify the molecular changes that influence the phenotypic characteristics of breast tumors, such as, changes in choline containing compound levels, lactate levels, extracellular pHe, vascular volume and permeability surface area product in Twist over-expressing as well in Twist down-regulated cells. Also, we will use non-invasive optical imaging to identify various stages of cancer progression using MCF-7/Twist cells transfected with an optical reporter gene (tdTomato). Finally, the gene signature patterns identified using the preclinical model will be applied to patient samples in order to identify potential markers of breast cancer progression. In the long term, these studies will help in the pathological diagnosis of breast cancer and provide insights that will contribute to the development of novel imaging markers and chemotherapeutic drugs for breast cancer. PUBLIC HEALTH RELEVANCE: Metastatic disease is the principle cause of death from breast cancer. Molecular characterization of this process is crucial to the development of novel diagnostic and therapeutic agents that will alleviate patient suffering and increase the survival rate. In this research proposal, we will use functional magnetic resonance imaging to identify the molecular changes that influence the phenotypic characteristics of breast tumors, such as, changes in choline containing compound levels, lactate levels, extracellular pHe, vascular volume and permeability surface area product in Twist over-expressing breast cancer cells. Finally, the gene signature patterns of metastatic progression identified using Twist over-expressing breast cancer cells in preclinical model will be applied to patient samples in order to identify potential markers of breast cancer progression.