Division of Pediatric Gastroenterology, Hepatology, and Nutrition, SUNY Downstate Medical Center, Brooklyn, NY, USA.
J Pediatr Gastroenterol Nutr. 2010 Nov;51(5):556-62. doi: 10.1097/MPG.0b013e3181ecd65d.
Barrett esophagus (BE) is a premalignant condition that develops due to prolonged gastroesophageal reflux disease (GERD). In some but not all cases, BE progresses to Barrett-associated adenocarcinoma. p27 is a tumor-suppressor protein that regulates the cell's division cycle and appears to be frequently inactivated in Barrett-associated adenocarcinoma due to increased degradation or cytoplasmic mislocalization. Reduced or mislocalized p27 would remove it from its nuclear targets and result in increased proliferation. Although bile acid and hydrochloric acid (HCl) are linked to the pathogenesis of BE, not every patient with BE has a history of GERD. Eosinophilic esophagitis mimics GERD, but eosinophil granule proteins, known to mediate inflammation, have not been linked to BE. It was unknown whether mediators of esophagitis affect p27 expression and/or localization in normal esophageal cells. We assessed the effects of bile acid, HCl, and eosinophil granule proteins on p27 protein expression, localization, and its ability to regulate cell proliferation.
Human esophageal epithelial (HET-1A) cells were incubated with chenodeoxycholic acid (CDC), HCl, and eosinophil granule proteins (major basic protein, MBP; and eosinophil peroxidase, EPO). Cell viability analysis, immunoblot, immunofluorescence microscopy, and flow cytometric analysis were performed.
Exposure of HET-1A cells to CDC, HCl, MBP, and EPO did not affect total p27 levels. CDC, HCl, MBP, and EPO caused mislocalization of p27 from the nucleus to the cytoplasm. Flow cytometry showed that CDC exposure also increased HET-1A cell proliferation.
Mislocalization of p27 caused by mediators of GERD or eosinophilic esophagitis may serve as an early marker of increased cell proliferation, which may contribute to the risk for esophageal dysplasia.
巴雷特食管（BE）是一种癌前病变，由于长期胃食管反流病（GERD）而发展。在某些但不是所有情况下，BE 进展为 Barrett 相关腺癌。p27 是一种肿瘤抑制蛋白，可调节细胞的分裂周期，由于降解增加或细胞质定位错误，似乎经常在 Barrett 相关腺癌中失活。减少或定位错误的 p27 将其从核靶标中去除，并导致增殖增加。尽管胆酸和盐酸（HCl）与 BE 的发病机制有关，但并非每个 BE 患者都有 GERD 病史。嗜酸细胞性食管炎模仿 GERD，但已知介导炎症的嗜酸粒细胞颗粒蛋白与 BE 无关。尚不清楚食管炎的介质是否会影响正常食管细胞中 p27 的表达和/或定位。我们评估了胆酸、HCl 和嗜酸粒细胞颗粒蛋白对 p27 蛋白表达、定位及其调节细胞增殖能力的影响。
用人食管上皮（HET-1A）细胞孵育鹅脱氧胆酸（CDC）、HCl 和嗜酸粒细胞颗粒蛋白（主要碱性蛋白，MBP；和嗜酸粒细胞过氧化物酶，EPO）。进行细胞活力分析、免疫印迹、免疫荧光显微镜和流式细胞术分析。
暴露于 HET-1A 细胞的 CDC、HCl、MBP 和 EPO 不会影响总 p27 水平。CDC、HCl、MBP 和 EPO 导致 p27 从核定位到细胞质。流式细胞术显示，CDC 暴露还增加了 HET-1A 细胞的增殖。
GERD 或嗜酸细胞性食管炎的介质引起的 p27 定位错误可能作为细胞增殖增加的早期标志物，这可能导致食管发育不良的风险增加。
