The Tissue Transglutaminase-Fibronectin Interaction in Ovarian Cancer Metastasis

描述（由申请人提供）： 卵巢癌（OC）是妇科恶性肿瘤中死亡率最高的肿瘤，而腹腔脏器转移是导致OC死亡的最常见原因。我们实验室的工作表明，组织转氨酶（TG 2），一种参与Ca 2+依赖性蛋白质翻译后修饰和交联的酶，在大多数卵巢肿瘤中高度表达，并严格调节腹膜转移。本研究小组在该基金的任期内进行的机制研究确定了TG 2和纤连蛋白（FN）之间的相互作用是腹膜转移过程中的关键因素。我们发表的工作表明，TG 2/FN复合物涉及：a）通过与整合素相互作用粘附到细胞外基质，B）诱导上皮向间充质转化，以及c）调节β-atenin信号传导，这反过来促进癌细胞增殖和维持癌症干细胞特征。这些初步数据提供了一个强有力的理由，追求进一步的机制研究，以了解蛋白质复合物如何调节致癌信号，导致癌症传播，并开始寻找这种复合物的抑制剂。为此，我们完成了对大型化合物库的高通量筛选，并发现了新的二氨基嘧啶作为TG 2/FN复合物的有效抑制剂。我们证明了这些小分子中的几种可以有效地阻断卵巢癌细胞的粘附和迁移，并选择TG 53作为进一步评估的先导化合物。基于我们在前一个资助期的发现，我们假设TG 2/FN复合物对OC转移的发展至关重要，并且其破坏将阻断肿瘤扩散。在这里，我们建议阐明TG 2/FN复合物启动致癌信号传导导致转移的机制，并在临床前鉴定出最高命中率。 在筛选过程中。在OC模型中利用生物化学和生物学测定的逐步方法将解决三个目标：目的1：表征TG 2/FN/整联蛋白复合物的形成激活EMT的机制。目的2：确定TG 2/FN/整合素复合物促进干细胞信号传导的机制。目的3：表征先导TG 2/FN抑制剂在OC转移模型中的作用。新发现的TG 2/FN抑制剂在临床前试验中的成功表征将为未来的临床应用提供基础。从长远来看，利用我们独特的专业知识和资源，这一系列创新研究将开发新的药物，以预防难以治疗的致命癌症的转移。

DESCRIPTION (provided by applicant): Ovarian cancer (OC) is the leading cause of death among gynecological malignancies and metastasis to abdominal organs is the most common cause of OC mortality. Work in our laboratory demonstrated that tissue transglutaminase (TG2), an enzyme involved in Ca2+-dependent protein post-translational modifications and cross-linking, is highly expressed in the majority of ovarian tumors and critically regulates peritoneal metastasis. Mechanistic studies performed by our group during the tenure of this grant identified the interaction between TG2 and fibronectin (FN) as a critical player in the process of peritoneal metastasis. Our published work demonstrated that the TG2/FN complex is implicated in: a) adhesion to the extracellular matrix through interaction with �ntegrins, b) induction of epithelial to mesenchymal transition, and c) regulation of �atenin signaling, which in turn promotes cancer cell proliferation and maintenance of a cancer stem cell profile. These preliminary data provide a strong rationale to pursue further mechanistic studies to understand how the protein complex regulates oncogenic signaling leading to cancer dissemination and to initiate a search for inhibitors of this complex. To this end, we completed high throughput screening of a large library of compounds and discovered new diamino-pyrimidines as potent inhibitors for the TG2/FN complex. We demonstrated that several of these small molecules potently blocked ovarian cancer cell adhesion and migration and selected TG53 as the lead compound to be further evaluated. Based on our discoveries during the previous funding period, we hypothesized that the TG2/FN complex is critical to the development of OC metastasis and that its disruption will block tumor dissemination. Here we propose to elucidate the mechanism by which TG2/FN complex initiates oncogenic signaling leading to metastasis and to characterize pre-clinically the top hit identified during the screening process. A step wise approach utilizing biochemical and biological assays in OC models will address three objectives: Aim 1: To characterize the mechanisms by which formation of the TG2/FN/integrin complex activates EMT. Aim 2: To define mechanisms engaged by TG2/FN/integrin complexes to promote stem cell signaling. Aim 3: To characterize the effects of the lead TG2/FN inhibitor in an OC metastasis model. Successful characterization of the newly discovered TG2/FN inhibitor in the preclinical assays proposed will provide the basis for future clinical applications. In the long term, this line of innovative research taking advantage of our unique expertise and resources will develop new agents to prevent metastasis in a difficult to treat, fatal cancer.