EPHB2-Dependent Signaling: A New Molecular Paradigm in Barrett's Neoplasia

项目摘要/摘要 Barrett‘s食道(BE)是一种位于食道远端的复杂的分子疾病，其病因学仍未得到证实。 难以捉摸。患有BE的患者患食管腺癌(EAC)的风险增加，EAC是一种致命的 在美国日益流行，也是最常见的食道恶性肿瘤。我们的长期目标是 明确BE发病和恶性进展的致病机制，并发展 循证生物标记物和后续临床实施的化学预防/治疗策略。 该计划的项目3是基于我们最近发现的EphB2受体酪氨酸激酶作为一种新的 巴雷特瘤的促进者。RNA测序结合通路建模在治疗初治患者中的应用 活组织检查显示绝大多数(90%)BE和EAC中EphB2信号显著过度激活 损伤。体外和体内的表型分析表明，EphB2信号转导通路在肿瘤的发生发展中起重要作用 EAC和发育不良/BE细胞的活性。随后的机制研究发现c-myc是一个新的靶点。 EphB2信号转导，而单细胞RNA测序进一步证实了食管祖细胞的强阳性 EphB2活化与柱状/BE样细胞谱系的关系总的来说，我们的研究表明EphB2 在BE-EAC发病机制中首次发现信号转导，并进一步揭示了EphB2与MYC之间的新联系。 任何疾病背景。在这些具有挑衅性的发现的基础上，我们现在提议全面描述 EphB2在Barrett瘤中的作用如下：在目标1中，我们将确定EphB2的激活是否是一种 柱状/Be化生发展的结果或先决条件。我们将测试是否激活了 Be前体细胞中的EphB2信号促进柱状/Be样转化状态。在目标2中，我们将 在体内确定EphB2激活在食道中的病理后果，使用结构性- 我们新近建立的活性EphB2激酶(Ephb2F613D)小鼠模型。我们将专门测试EphB2是否 激活诱导食管内BE样化生和异型增生/癌；自发地，或在 暴露于反流损伤，和/或在食管炎的环境中。我们将进一步描述密钥的特征 EphB2在食道中的激活扰乱了分子程序。在目标3中，我们将确定下游 以及EphB2信号的上游调节级联。总而言之，我们建议的研究将勾勒出 首次发现了EphB2信号转导机制，揭示了BE-EAC发病的新驱动机制。

PROJECT SUMMARY/ABSTRACT The etiology of Barrett's esophagus (BE), a molecularly complex disorder of the distal esophagus, remains elusive. Patients with BE are at an increased risk of developing esophageal adenocarcinoma (EAC), a lethal, increasingly prevalent, and the most common esophageal malignancy in the U.S. Our long-term objective is to identify the causative mechanisms underlying the onset and malignant progression of BE, and to develop evidence-based biomarkers and chemopreventive/therapeutic strategies for subsequent clinical implementation. Project 3 of this program is based on our recent discovery of EphB2 Receptor Tyrosine Kinase as a novel promoter of Barrett's neoplasia. RNA sequencing coupled with pathway modeling in treatment-naïve patient biopsies showed significant hyperactivation of EphB2 signaling in the vast majority (>90%) of BE and EAC lesions. Phenotypic assessments in vitro and in vivo demonstrated EphB2 signaling to be essential for the viability of EAC and dysplastic/BE cells. Subsequent mechanistic studies identified c-MYC as a novel target of EphB2 signaling, while single-cell RNA sequencing of esophageal progenitor cells further confirmed a strong association of EphB2 activation with columnar/BE-like cell lineage. Collectively, our study implicates EphB2 signaling for the first time in BE-EAC pathogenesis, and further reveals a novel link between EphB2 and MYC in any disease context. Expanding on these provocative findings, we now propose to fully characterize the biologic role of EphB2 in Barrett's neoplasia as follows: In Aim 1, we will determine whether EphB2 activation is a consequence of, or a pre-requisite for, columnar/BE metaplasia development. We will test whether activation of EphB2 signaling in putative BE-progenitor cells promote columnar/BE-like transformative state. In Aim 2, we will determine the pathologic consequences of EphB2 activation in vivo in the esophagus, using a constitutively- active EphB2 kinase (Ephb2F613D) mouse model that we recently developed. We will specifically test if EphB2 activation induces BE-like metaplasia and dysplasia/cancer in the esophagus; either spontaneously, or upon exposure to reflux injury, and/or in the setting of esophageal inflammation. We will further characterize the key molecular programs disrupted by EphB2 activation in the esophagus. In Aim 3, we will determine the downstream and upstream regulatory cascades of EphB2 signaling. Collectively, our proposed studies will delineate the role of EphB2 signaling for the first time, uncovering novel driver mechanisms of BE-EAC pathogenesis.