Receptor Cross-Talk in Early Metastatic Dissemination

描述(申请人提供)：腹内播散性转移是上皮性卵巢癌妇女死亡的主要原因，表明对转移过程的干预可能显著提高卵巢癌患者的长期存活率。转移表型的获得涉及一系列复杂的相互关联的细胞事件，导致恶性肿瘤细胞从原发肿瘤中分离(脱落)。这一过程中的一个关键事件是通过调节细胞间连接成分来破坏细胞与细胞的接触。该项目的总体目标是确定促成恶性细胞扩散的事件之间的相互关系，因为对这些过程的更详细了解将转化为新的诊断和治疗策略。原发性高分化卵巢癌的一个独特特征是细胞-细胞黏附分子E-钙粘附素的表达增加，随后 E-钙粘附素在肿瘤转移过程中的表达和/或功能。我们目前的发现表明，表皮生长因子受体(EGFR)的配体激活、突变激活或反式激活调节了连接溶解和随后的细胞扩散所需的关键细胞事件。拟议的实验将检验这一假设，即微环境因素通过启动激活的EGFR和钙粘附素之间的串扰来影响转移扩散，从而调节E-钙粘附素的表达和功能，导致转移细胞从原发肿瘤中脱落。为了解决这一假设，目标1将通过检测EGFR激活对E-钙粘蛋白表达、功能和运输的调节作用来评估E-钙粘蛋白连接完整性的微环境调节因素。E-钙粘附素功能下调对间充质标记物的获得和蛋白酶表达的影响也将被评估。目的研究E-钙粘蛋白胞外区(Se-Cadherin)蛋白水解性释放动力学，并利用器官扩散模型评价Se-Cadherin对细胞间黏附和细胞分散的影响。AIM 3中提出的翻译研究将评估卵巢肿瘤微阵列中EGFR激活、蛋白酶表达、钙粘附素状态和胞外结构域脱落之间的关系，并研究腹水中的微环境调节因素。拟议的综合分析将填补知识的重大空白，并提供有关以下方面的新数据：(A)早期和晚期肿瘤和转移瘤的E-和N-钙粘素状态；(B)卵巢肿瘤从高分化肿瘤到低分化肿瘤进展过程中的EGFR激活和EMT；以及(C)可与肿瘤组织持续相互作用的可溶性微环境调节剂的存在。相关性：建议的研究利用一种新的综合方法来解决增强卵巢癌转移的分子机制。临床上的一个主要需求仍然是针对转移性疾病的卵巢癌特异性治疗。

DESCRIPTION (provided by applicant): Disseminated intra-abdominal metastasis is the leading cause of death for women with epithelial ovarian carcinoma, indicating that intervention with the metastatic process may significantly improve long-term survival of ovarian cancer patients. Acquisition of the metastatic phenotype involves a complex series of interrelated cellular events leading to dissociation (shedding) of malignant cells from the primary tumor. A key event in this process is disruption of cell-cell contacts via modulation of intercellular junctional components. The overall goal of this project is to define the interrelationships between events that contribute to dissemination of malignant cells, as a more detailed understanding of these processes will translate into novel diagnostic and therapeutic strategies. A unique feature of primary well-differentiated ovarian cancers is an increase in expression of the cell-cell adhesion molecule E-cadherin, with subsequent loss of E-cadherin expression and/or function during progression to metastasis. Our current findings indicate that ligand-, mutational-, or trans-activation of the epidermal growth factor receptor (EGFR) modulates key cellular events required for junction dissolution and subsequent cellular dissemination. Proposed experiments will test the hypothesis that microenvironmental factors influence metastatic dissemination by initiating cross-talk between activated EGFR and cadherins, thereby modulating E-cadherin expression and function, resulting in shedding of metastatic cells from the primary tumor. To address this hypothesis, Aim 1 will evaluate microenvironmental regulators of E-cadherin junctional integrity by examining the effect of EGFR activation on modulation of E-cadherin expression, function and trafficking. The impact of E-cadherin functional downregulation on acquisition of mesenchymal markers and proteinase expression will also be evaluated. Aim 2 will characterize the kinetics of proteolytic release of the E-cadherin ectodomain (sE-cadherin) and evaluate the effects of sE-cadherin on cell-cell adhesion and cellular dispersion using organotypic dissemination models. Translational studies proposed in Aim 3 will evaluate the relationship between EGFR activation, proteinase expression, cadherin status and ectodomain shedding in ovarian tumor microarrays and investigate microenvironmental regulators in ascites. The proposed integrative analysis will fill significant gaps in knowledge and provide novel data regarding (a) E- and N-cadherin status of early and late stage tumors and metastases, (b) EGFR activation and EMT in ovarian tumor progression from well- to poorly- differentiated tumors, and (c) the presence of soluble microenvironmental regulators positioned for sustained interaction with tumor tissues. Relevance: The proposed studies utilize a novel integrative approach to address molecular mechanisms that potentiate ovarian cancer metastasis. A major clinical need remains for ovarian cancer-specific therapies that target metastatic disease.