MRI and MRS of Hormonal Induced Changes in Breast Cancer

描述（由申请人提供）： 该提案的长期目标是通过磁共振成像和光谱学开发用于预测和评估乳腺癌对激素治疗的反应的非侵入性方法。基于上一个支持期获得的结果，我们建议继续研究雌激素诱导的血管生成和糖酵解变化的分子基础。具体而言，我们想检验这样的假设，即雌激素与雌激素受体α（ER α）的相互作用激活致癌核转录因子c-myc，c-myc反过来下调血管内皮生长因子（VEGF）的表达并上调葡萄糖转运蛋白1（GLUT 1）的表达，从而通过糖酵解影响肿瘤灌注和葡萄糖转运和代谢。在这一建议中，我们首次描述了一项计划，即开发一种新的、定量的和非侵入性的方法，通过分子成像来评估乳腺癌中雌激素受体的水平。因此，我们打算合成和测试他莫昔芬衍生的和雌激素衍生的甾体金属络合物，其发荧光或改变交换水的MR参数，以及与荧光或MRI探针缀合的肽，其特异性结合配体结合的ER α。分子生物学和MRI的实验整合将涉及人类乳腺癌细胞的研究（ER α +阳性和ER α阴性的比较），包括新开发的HCF 7细胞的ER α +阳性克隆，35 im，其携带稳定转染的人类c-myc基因，其表达受细菌逆转录四环素转录激活蛋白的严格控制。我们将继续研究这些细胞植入小鼠（免疫缺陷或严重免疫缺陷小鼠）的原位肿瘤，在不同的激素操纵下，雌激素和抗雌激素。具体目标旨在在分子、细胞和整个肿瘤水平上测试上述假设，并开发和测试用于雌激素受体分子成像的靶向探针。实验方案包括利用分子和免疫组织化学方法，将表征c-myc表达与VEGF和GLUT 1表达，在不同的激素治疗的细胞和肿瘤。此外，将致力于开发新的非侵入性MRI和MRS方法，以监测激素诱导的血管特性变化以及葡萄糖转运和代谢。雌激素受体靶向探针的合成已经开始。将在体外和体内测试新探针与ER α的结合特异性、进入细胞的转运参数以及对细胞和整个动物的药理学和毒理学作用。基于存在约1000 fmol/mg受体蛋白（MCF 7细胞中的水平）的预测表明T1和T2* 的变化很小但可测量。这项工作将增加对乳腺癌激素调节的基本理解，也可能有助于设计和改善乳腺癌抗雌激素和抗血管生成治疗的新靶点。功能性雌激素活性的成像方法可以作为在动物模型中测量新的选择性雌激素受体调节剂的功效的基础，当前的提议也将使我们更接近于非侵入性地成像雌激素受体水平和证明其功能活性的参数的能力。反过来，这可能会显着改善预后的评估和管理的约75%的乳腺癌患者的ER阳性肿瘤。

DESCRIPTION (provided by applicant): The long-range objective of this proposal is to develop non-invasive methods for predicting and evaluating the response of breast cancer to hormonal therapy, by means of magnetic resonance imaging and spectroscopy. Based on the results obtained in the last supported period, we propose to continue investigating the molecular basis for estrogen-induced changes in angiogenesis and glycolysis. Specifically, we would like to test the hypothesis that estrogen interaction with the estrogen receptor alpha (ERalpha) activates the oncogenic nuclear transcription factor c-myc, which in turn down-regulates the expression of vascular endothelial growth factor (VEGF) and up-regulates the expression of glucose transporter 1 (GLUT1), thereby affecting tumor perfusion and glucose transport and metabolism through glycolysis, Furthermore, in this proposal we describe for the first time a plan to develop a new, quantitative and noninvasive approach to evaluate the level of estrogen receptors in breast cancer by means of molecular imaging. Accordingly, we intend to synthesize and test tamoxifen-derived and estrogen-derived steroidal metal-complexes that fluoresce or modify MR parameters of exchanging water, as well as peptides conjugated to fluorescent or MRI probes that bind specifically to the ligand bound ERalpha. The experimental integration of molecular Biology and MRI will involve studies of human breast cancer cells (ERalpha+-positive and ERalpha-negative for comparison), including a newly developed ERalpha+-positive clone of HCF7 cells, 35im, that is harboring a stably transfected human c-myc gene, whose expression is stringently controlled by the bacterial reverse tetracycline transcription activator protein. We will proceed to investigate the orthotopic tumors of these cells implanted in mice (immunodeficient or sever compromised immunodeficient mice), under varying hormonal manipulation by estrogen and antiestrogens. The specific aims are designed to test the above hypothesis at the molecular, cellular and whole tumor levels and to develop and test targeted probes for molecular imaging of the estrogen receptor. The experimental protocols include utilizing molecular and immunohistochemical methods that will characterize c-myc expression in conjunction with VEGF and GLUT1 expression, under varying hormonal treatments of cells and tumors. In addition, efforts will be devoted to develop new, non invasive MRI and MRS methods that would enable monitoring hormonal induced changes in the vasculature properties as well as glucose transport and metabolism. The synthesis of the estrogen receptor targeted probes was already initiated. The new probes will tested in vitro and in vivo for their binding specificity to ERalpha, the transport parameters into the cells and the pharmacological and toxicological effects on cells and whole animals. Prediction based on the presence of about 1000 fmol/mg protein of the receptor (the level in MCF7 cells) indicated a small but measurable change in T1 and T2*. This work will add to the basic understanding of the hormonal regulation of breast cancer and may also help design and improve new targets for anti-estrogenic and anti-angiogenic therapy of breast cancer. The methods of imaging functional estrogen activities may serve as a basis for measuring the efficacy of new selective estrogen receptor modulators in animal models, The current proposal will also bring us closer to the capacity of imaging, non-invasively, both the estrogen receptor level and the parameters demonstrating its functional activity. This, in turn, may improve significantly the assessment of prognosis and the management of the approximate 75% of the breast cancer patients with ER-positive tumors.