Role of p120ctn in Esophageal Cancer

描述（申请人提供）：食管癌是全球男性第五大常见癌症。由于生存率低，诊断时病情进展较晚，发病频率越来越高，因此了解这些肿瘤发生的分子机制以及参与其转移的基因变得越来越重要。我的研究将集中在catenin家族成员p120ctn及其在体外和体内调节肿瘤发生以及细胞迁移和侵袭的能力。p120ctn定义了一个与β -连环蛋白相关的连环蛋白家族，该家族也与e -钙粘蛋白结合，并在粘附连接处稳定e -钙粘蛋白。因此，E-cadherin和p120ctn的表达似乎在许多细胞系中受到协调调节，推测这可能是E-cadherin表达丢失并导致EMT的另一种机制。有趣的是，p120ctn包含16个不同的磷酸化位点，8个酪氨酸和8个丝氨酸/苏氨酸。哪些激酶直接使这些位点磷酸化，以及在何种刺激下使这些位点磷酸化，在很大程度上是未知的。然而，很明显，EGFR激活可以诱导p120ctn的磷酸化，至少在Y228。此外，p120ctn存在许多剪接形式。我们假设p120ctn的不同异构体和磷酸化位点可能调节其与结合伙伴相互作用的能力，从而改变其促进肿瘤发生和转移的能力。这一假设将通过以下相互关联的具体目标来实现。目的1：评估不同亚型和磷酸化突变体对运动性和侵袭性的影响。p120ctn在多种食道细胞系中表达下调。将介绍各种异构体和磷酸化缺陷突变体，并通过单层分析以及三维矩阵和器官型培养模型确定突变体的运动性和侵袭性。目的2：了解p120ctn在肿瘤发生和发展中的作用。我们将在体内和体外过表达EGFR并敲低p120ctn的表达。我们将对这些egfr过表达、p120ctn缺失的小鼠和细胞系进行食管肿瘤发生和转移的监测。去年，美国确诊了14000多例食管癌新病例，其中90%以上的患者将死于疾病，主要死于转移性病变。拟议的研究将为p120ctn在食管癌发生和进展中的生物学作用提供新的见解。最终，这些研究可能转化为这种致命疾病的新的诊断和治疗方式。

DESCRIPTION (provided by applicant): Esophageal cancer represents the 5th most frequent cancer in males worldwide. Given the poor survival rate, advanced stage of the disease at diagnosis and the increasing frequency of the disease it is increasingly important to understand the molecular mechanisms of initiation of these tumors as well as the genes involved in their metastasis. My research will focus on the catenin family member p120ctn and its ability to modulate tumorigenesis as well as cell migration and invasion in vitro and in vivo. p120ctn defines a family of catenin proteins related to beta-catenin that also bind to E-cadherin and stabilizes E-cadherin at adherens junctions. As a result, expression of E-cadherin and p120ctn appear to be coordinately regulated in many cell lines and it is speculated that this may be another mechanism by which E-cadherin expression may be lost and lead to EMT. Interestingly, p120ctn contains 16 different phosphorylation sites, 8 tyrosine and 8 serine/threonine. What kinases directly phosphorylate these sites and under what stimuli are largely unknown. However, it is clear that EGFR activation can induce phosphorylation of p120ctn at least at Y228. Additionally, many splice forms for p120ctn exist. We hypothesize that the different isoforms and phosphorylation sites of p120ctn may regulate its ability to interact with its binding partners and therefore alter its ability to promote tumorigenesis and metastasis. This hypothesis will be pursued by the following interrelated specific aims. Aim 1: To assess the effects different isoforms and phosphorylation mutants have on motility and invasiveness. Expression of p120ctn will be knocked-down in several esophageal cell lines. Various isoforms and phosphorylation-deficient mutants will be introduced and motility and invasiveness of the mutants will be determined through monolayer assays as well as three-dimensional Matrigel and organotypic culture models. Aim2: To understand the role of p120ctn in tumor initiation and progression. We will overexpress EGFR and knockdown p120ctn expressin in vivo and in vitro. We will monitor these EGFR-overexpressing, p120ctn-deleted mice and cell lines for esophageal tumorigenesis and metastasis. Over 14,000 new cases of esophageal cancer were diagnosed in the United States last year and more than 90% of those diagnosed will die of their disease, primarily from metastatic lesions. The proposed studies will provide novel insights into the biological roles of p120ctn in the development and progression of esophageal cancer. Ultimately, these studies may translate into new diagnostic and therapeutic modalities for this deadly disease.