Reflux-Induced Epithelial-Mesenchymal Transition in Benign Barrett's Esophagus

良性巴雷特食管反流诱导的上皮间质转化

• 批准号: 8996772
• 负责人: RHONDA F SOUZA
• 金额: $ 28.35万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-23 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8996772
• 关键词: Ablation; Acids; Acute; Adenocarcinoma; Adult; Adverse effects; American; Barrett Esophagus; Benign; Bile Acids and Salts; Binding; Cancer Etiology; Cancer Patient; Cell Line; Cells; Cessation of life; Characteristics; Creation of jejunostomy; Data; Development; Dysplasia; Endoscopic Biopsy; Epithelial; Epithelial Cells; Esophageal; Esophageal Adenocarcinoma; Esophagus; Exhibits; Exposure to; Failure; Gastric Juice; Gastroesophageal reflux disease; Gland; Hypoxia Inducible Factor; In Vitro; Inflammation; Interruption; Intestinal Metaplasia; Intestines; Lamina Propria; Malignant Neoplasms; Malignant neoplasm of esophagus; Mediating; Medical; Mesenchymal; Metaplasia; Metaplastic; Modeling; Mucous Membrane; Nuclear; Patients; Peptic Esophagitis; Procedures; Process; Production; Proton Pump Inhibitors; Public Health; Radiofrequency Interstitial Ablation; Rattus; Reactive Oxygen Species; Recurrence; Reflux; Risk Factors; Role; Signal Transduction; Source; Squamous Epithelium; Telomerase; Vascular Endothelial Growth Factor Receptor; Vascular Endothelial Growth Factors; Wound Healing; autocrine; bile salts; cell motility; in vivo; neoplastic; neoplastic cell; prevent; programs; tumor; tumor progression

Project Summary It has been estimated that 5.6% of adult Americans have Barrett’s esophagus (BE), a major risk factor for esophageal adenocarcinoma. To prevent this cancer, patients with BE are advised to have regular endoscopic surveillance for dysplasia, and to have that dysplasia treated with radiofrequency ablation (RFA). Unfortunately, surveillance has not prevented deaths from esophageal cancer, and Barrett’s metaplasia recurs frequently after RFA. Surveillance failures and metaplasia recurrences might be due to subsquamous intestinal metaplasia (SSIM), a condition in which metaplastic glands are located in the lamina propria under a layer of squamous epithelium that hides them from the endoscopist and shields them from destruction by RFA. SSIM initially was considered a side effect of endoscopic ablation, but recent studies show that SSIM is present in the large majority of Barrett’s patients who have not had ablation procedures. This highly prevalent SSIM might be the source of tumors missed by endoscopic surveillance, and the nidus for recurrent metaplasia after RFA. Thus, SSIM appears to be a frequent and important condition that limits the efficacy of endoscopic surveillance for the millions of patients with BE, and that thwarts endoscopic attempts to eradicate BE and prevent its progression to cancer. Epithelial-mesenchymal transition (EMT) is the process in which epithelial cells acquire mesenchymal characteristics including cell migration. In BE, EMT could enable metaplastic Barrett’s epithelial cells to migrate into the lamina propria underneath adjacent squamous epithelium, resulting in SSIM. In our rat model in which we induce reflux esophagitis by creating an esophago-jejunostomy, our preliminary data strongly suggest that jejunal epithelial cells adjacent to ulcerated esophageal squamous mucosa undergo EMT, which contributes to the development of a columnar-lined esophagus with features of Barrett’s metaplasia including SSIM. Gastroesophageal reflux causes esophageal inflammation and production of reactive oxygen species, conditions that can activate hypoxia inducible factors (HIFs). Our preliminary data show that Barrett’s epithelial cells exposed to acid and bile salts exhibit a strong and sustained increase in nuclear HIF-1α and HIF-2α. In patients with BE, we also show that HIF-1α and HIF-2α levels in their Barrett’s metaplasia rise when the esophagus is perfused with acid or bile salts. HIFs can promote EMT by causing cells to secrete vascular endothelial growth factor (VEGF), which binds the cells’ VEGF receptors in an autocrine fashion to induce VEGF signaling that triggers EMT. Our preliminary data show that acid and bile salts induce autocrine VEGF signaling and EMT features in Barrett’s cell lines. Therefore, we hypothesize that reflux-induced activation of HIFs in Barrett’s epithelial cells causes VEGF secretion with autocrine VEGF signaling, which initiates the EMT program and causes SSIM. The aims of this study are to elucidate the mechanism(s) whereby acid and bile salts activate HIFs to cause VEGF production, and to explore the role of autocrine VEGF signaling in the EMT program induced by acid and bile salts in Barrett’s cells in vitro, and in BE patients with reflux esophagitis.

项目概要 据估计，5.6% 的美国成年人患有巴雷特食管 (BE)，这是食管癌的一个主要危险因素 食管腺癌。为了预防这种癌症，建议 BE 患者定期接受内窥镜检查 监测不典型增生，并通过射频消融 (RFA) 治疗不典型增生。很遗憾， 监测并没有阻止食管癌死亡，并且巴雷特化生在食管癌后经常复发 射频消融。监测失败和化生复发可能是由于鳞状下肠化生 （SSIM），化生腺位于固有层鳞状细胞层下的一种情况 上皮细胞将它们隐藏起来，不被内窥镜医师发现，并保护它们免受 RFA 的破坏。 SSIM最初是 被认为是内镜消融的副作用，但最近的研究表明，SSIM 存在于绝大多数患者中 未接受消融手术的巴雷特患者。这种高度流行的 SSIM 可能是 内窥镜监测漏掉的肿瘤，以及 RFA 后复发化生的病灶。于是，SSIM出现了 是一种常见且重要的情况，限制了内窥镜监测对数百万患者的有效性 BE 患者，这阻碍了内窥镜根除 BE 并防止其进展为癌症的尝试。 上皮-间质转化（EMT）是上皮细胞获得间质的过程 特征包括细胞迁移。在 BE 中，EMT 可以使化生巴雷特上皮细胞迁移 进入邻近鳞状上皮下方的固有层，导致 SSIM。在我们的大鼠模型中 我们通过食管空肠造口术诱发反流性食管炎，我们的初步数据强烈表明 与溃疡的食管鳞状粘膜相邻的空肠上皮细胞经历 EMT，这有助于 具有 Barrett 化生特征（包括 SSIM）的柱状内衬食管的发育。 胃食管反流导致食管炎症和活性氧的产生， 可以激活缺氧诱导因子（HIF）的条件。我们的初步数据显示巴雷特上皮细胞 暴露于酸和胆盐的细胞表现出核 HIF-1α 和 HIF-2α 的强烈且持续的增加。在 BE 患者中，我们还发现，当他们的 Barrett 化生中的 HIF-1α 和 HIF-2α 水平升高时， 食道充满酸或胆汁盐。 HIFs可以通过使细胞分泌血管分泌物来促进EMT 内皮生长因子 (VEGF)，以自分泌方式结合细胞的 VEGF 受体，诱导 触发 EMT 的 VEGF 信号传导。我们的初步数据表明，酸和胆盐诱导自分泌 VEGF Barrett 细胞系中的信号传导和 EMT 特征。因此，我们假设反流诱导的激活 Barrett 上皮细胞中的 HIF 通过自分泌 VEGF 信号传导引起 VEGF 分泌，从而启动 EMT 程序并导致 SSIM。本研究的目的是阐明酸和胆汁的作用机制 盐激活 HIF 导致 VEGF 产生，并探索自分泌 VEGF 信号传导在 EMT 中的作用 体外 Barrett 细胞中以及患有反流性食管炎的 BE 患者中由酸和胆汁盐诱导的程序。