Department of Biology, University of Rochester, Rochester, NY, USA.
J Gastrointest Surg. 2013 Oct;17(10):1723-31. doi: 10.1007/s11605-013-2287-1. Epub 2013 Aug 7.
Barrett's esophagus is a preneoplastic metaplasia in which the normal squamous epithelium of the esophagus changes to an intestinal, columnar phenotype due to long-term gastro-esophageal reflux. The major components of this reflux are bile and stomach acid. Previous in vitro studies on the effect of bile and acid on esophageal cells have predominantly relied on transformed esophageal squamous cells or cancer cells grown in monolayer culture.
In this study, we expanded our previous work using an immortalized primary esophageal squamous cell line (EPC1). We demonstrate that EPC1 cells form a multi-layer, stratified epithelium when grown on polyester transwell filters in media supplemented with calcium. When exposed to short pulses of bile and pH 5, but not either condition alone, EPC1 cells demonstrate a reduction in stratification layers and reduced expression of squamous epithelium-specific genes. Bile at pH 5 also causes activation of epidermal growth factor receptor and down-stream pathways. Blocking epidermal growth factor receptor activation partially attenuates the effects of bile acid and pH 5. These results suggest that bile at low pH, but not bile or low pH alone, promotes loss of differentiation status of stratified squamous esophageal epithelium in vitro, possibly by initiating a mucosal repair response through epidermal growth factor activation.
巴雷特食管是一种癌前病变，由于长期胃食管反流，食管正常的鳞状上皮转变为肠型柱状上皮。这种反流的主要成分是胆汁和胃酸。以前关于胆汁和胃酸对食管细胞影响的体外研究主要依赖于转化的食管鳞状细胞或单层培养的癌细胞。
在这项研究中，我们扩展了之前使用永生化的原代食管鳞状细胞系（EPC1）的工作。我们证明，当在含有钙的培养基中生长在聚酯 Transwell 过滤器上时，EPC1 细胞形成多层、分层的上皮。当暴露于短时间的胆汁和 pH5 时，但不是单独暴露于这两种条件下，EPC1 细胞表现出分层层数减少和鳞状上皮特异性基因表达减少。pH5 的胆汁也会激活表皮生长因子受体及其下游途径。阻断表皮生长因子受体的激活部分减弱了胆汁酸和 pH5 的作用。这些结果表明，低 pH 值的胆汁，但不是胆汁或低 pH 值本身，可促进体外分层鳞状食管上皮的分化状态丧失，可能通过表皮生长因子激活启动黏膜修复反应。
