Transcriptional Regulation of Breast Cancer Metastasis within the Tumor Microenvi

描述（由申请人提供）：乳腺癌从原发部位转移导致死亡。最近，研究人员发现，在转移性微环境中，播散所需的侵袭性肿瘤特性可能会恢复，从而使播散成为可能，部分原因是e -钙粘蛋白甲基化的逆转。允许乳腺癌细胞从原发肿瘤扩散的初始间质转化是通过EGFR家族信号（HER1和HER2）驱动的。然而，在转移播种过程中，EGFR家族信号下调，E-cadherin重新表达。我们提供的初步数据显示Kaiso的下调，或限制Kaiso从细胞核，驱动乳腺癌细胞向分化上皮样表型。因此，我们的转移性种子的新基础模型假设了一个关键的分子联系，使乳腺癌细胞能够融入异位环境，甚至进入休眠状态，即将Kaiso保留在细胞核外，以便e-钙粘蛋白可以重新表达。在这个提议中，我们将建立转移播种和肿瘤休眠都可以最小化，如果不通过调节这个分子级联消除。要测试的目标是具体目标1。确定EGF受体信号传导如何导致Kaiso重新定位到细胞核，以及这是否会改变DNA甲基化和癌细胞表型。为此，我们将1)确定自分泌EGFR信号传导对乳腺癌中Kaiso定位/表达和E-cadherin甲基化状态的影响；2)利用药理学和分子结构确定Kaiso在细胞核外隔离后的乳腺癌表型；3)确定EGF受体信号传导/级联如何协调改变乳腺癌细胞系中Kaiso亚细胞定位和DNA甲基化。具体目标2。1)确定Kaiso再定位到细胞核的中断是否会改变转移生态位的进入和/或肿瘤休眠的发展。我们将把癌细胞引入生物反应器，并确定Kaiso的定位以及E-cadherin在初始转移播种期间的表达。2）

DESCRIPTION (provided by applicant): Breast carcinoma escape from the primary site leads to mortality. Recently, it has been found that tumor properties of aggressiveness required for dissemination may revert within metastatic microenvironment to enable seeding, in part through reversal of methylation of E-cadherin. The initial mesenchymal transition that allows breast cancer cells to disseminate from the primary tumor is driven via EGFR family signaling (HER1 and HER2). However, during metastatic seeding, EGFR family signaling is downregulated and E-cadherin is re-expressed. We present preliminary data showing that downregulation of Kaiso, or restricting Kaiso from the nucleus, drives breast cancer cells towards a differentiated epithelial-like phenotype. Thus, our novel foundational model of metastatic seeding posits a key molecular link that enables the breast carcinoma cells to incorporate into the ectopic environment and even become dormant, that of retaining Kaiso out of the nucleus so that E-cadherin can be re-expressed. In this proposal we will establish that both metastatic seeding and tumor dormancy can be minimized if not eliminated by modulating this molecular cascade. The aims to be tested are Specific Aim 1. Determine how EGF receptor signaling causes relocalization of Kaiso into the nucleus and whether this alters DNA methylation and the carcinoma cell phenotype. In this aim, we will 1) Determine the influence of autocrine EGFR signaling on Kaiso localization/expression and methylation status of E-cadherin in breast cancer, and 2) Determine breast cancer phenotype upon sequestration of Kaiso outside of the nucleus, using pharmacological and molecular constructs, and 3) Determine how EGF receptor signaling/cascade coordinately alters Kaiso subcellular localization and DNA methylation in breast cancer cell lines. Specific Aim 2. 1) Determine whether disruption of Kaiso relocalization into the nucleus alters entry into the metastatic niche and/or the development of tumor dormancy. We will introduce the carcinoma cells into the bioreactor and determine the localization of Kaiso along with the expression of E-cadherin during initial metastatic seeding. 2) Determine the influence of sequestering Kaiso localization outside of the nucleus on tumor dormancy within the organotypic liver microenvironment. 3) Determine the role of nuclear Kaiso on the two steps of escape from the primary tumor and seeding of the metastatic microenvironment in animals. In summary, through the use of primary human explants, established lines, and an innovative human organotypic liver bioreactor as well as animal models, we will determine Kaiso localization and expression levels and that correlate with cell phenotype and cellular behaviors with the tumor microenvironment. Successful completion of these studies would could have immediate impact be on the basic science of tumor biology, and provide paradigm shifting insights into the molecular mechanisms by which breast carcinomas metastasize and enter dormancy, one of the most chilling aspects of progression.