Jaiswal Kshama, Lopez-Guzman Christie, Souza Rhonda F, Spechler Stuart J, Sarosi George A
Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas 75216, USA.
Am J Physiol Gastrointest Liver Physiol. 2006 Feb;290(2):G335-42. doi: 10.1152/ajpgi.00167.2005. Epub 2005 Oct 20.
Bile reflux has been implicated in the neoplastic progression of Barrett's esophagus (BE). Bile salts increase proliferation in a Barrett's-associated adenocarcinoma cell line (SEG-1 cells) by activating ERK and p38 MAPK pathways. However, it is not clear that these findings in cancer cells are applicable to non-neoplastic cells of benign BE. We examined the effect of bile salts on three human cell lines: normal esophageal squamous (NES) cells, non-neoplastic Barrett's cells (BAR cells), and SEG-1 cells. We hypothesized that bile salt exposure activates proproliferative and antiapoptotic pathways to promote increased growth in BE. NES, BAR, and SEG-1 cells were exposed to glycochenodeoxycholic acid (GCDA) at a neutral pH for 5 min. Proliferation was measured by Coulter counter cell counts and a 5-bromo-2'-deoxyuridine (BrdU) incorporation assay. GCDA-induced MAPK activation was examined by Western blot analysis for phosphorylated ERK and p38. Apoptosis was measured by TdT-mediated dUTP nick-end labeling and annexin V staining after GCDA and UV-B exposure. Statistical significance was determined by ANOVA. NES cells exposed to 5 min of GCDA did not increase cell number. In BAR cells, GCDA exposure increased cell number by 31%, increased phosphorylated p38 and ERK levels by two- to three-fold, increased BrdU incorporation by 30%, and decreased UV-induced apoptosis by 15-20%. In conclusion, in a non-neoplastic Barrett's cell line, GCDA exposure induces proliferation by activation of both ERK and p38 MAPK pathways. These findings suggest a potential mechanism whereby bile reflux may facilitate the neoplastic progression of BE.
胆汁反流与巴雷特食管（BE）的肿瘤进展有关。胆汁盐通过激活ERK和p38丝裂原活化蛋白激酶（MAPK）途径，增加巴雷特相关腺癌细胞系（SEG-1细胞）的增殖。然而，癌细胞中的这些发现是否适用于良性BE的非肿瘤细胞尚不清楚。我们研究了胆汁盐对三种人类细胞系的影响：正常食管鳞状（NES）细胞、非肿瘤性巴雷特细胞（BAR细胞）和SEG-1细胞。我们假设胆汁盐暴露会激活促增殖和抗凋亡途径，以促进BE中细胞生长增加。将NES、BAR和SEG-1细胞在中性pH值下暴露于甘氨鹅脱氧胆酸（GCDA）中5分钟。通过库尔特计数器细胞计数和5-溴-2'-脱氧尿苷（BrdU）掺入试验测量增殖。通过蛋白质免疫印迹分析磷酸化的ERK和p38，检测GCDA诱导的MAPK激活。在GCDA和UV-B暴露后，通过末端脱氧核苷酸转移酶介导的dUTP缺口末端标记和膜联蛋白V染色测量细胞凋亡。通过方差分析确定统计学显著性。暴露于GCDA 5分钟的NES细胞数量没有增加。在BAR细胞中。暴露于GCDA使细胞数量增加31%，使磷酸化的p38和ERK水平增加两到三倍，使BrdU掺入增加30%，并使紫外线诱导的细胞凋亡减少15%-20%。总之，在非肿瘤性巴雷特细胞系中，GCDA暴露通过激活ERK和p38 MAPK途径诱导增殖。这些发现提示了一种潜在机制，胆汁反流可能借此促进BE的肿瘤进展。
