Original article Effect of estrogen on growth and apoptosis in esophageal adenocarcinoma cells O. A. Sukocheva, C. Wee, A. Ansar, D. J. Hussey, D. I. Watson Department of Surgery, and Flinders Centre for Cancer Prevention and Control, Flinders Medical Centre, Flinders University, Bedford Park, South Australia, Australia SUMMARY. The epidemiology of esophageal adenocarcinoma demonstrates a strong gender bias with a sex ratio of 8–9:1 in favor of males. A potential explanation for this is that estrogen might protect against esophageal adenocarcinoma. Estrogen has previously been shown to stimulate apoptosis in esophageal squamous cancer cells. However, the effect of estrogen on esophageal adenocarcinoma cells has not been determined. We used immuno- blotting analysis to determine the expression of estrogen receptors, cell adhesion marker E-cadherin, and prolif- eration marker Ki-67 in cell lines derived from esophageal adenocarcinoma (OE-19, OE-33) and Barrett’s esophagus (QhTRT, ChTRT, GihTRT). Estrogen and selective estrogen receptor modulator (SERM)-dependent effects on cell growth were determined by the CellTiter-96 Aqueous Proliferation Assay. Apoptosis was determined by Annexin V/Propidium Iodide cell labeling and flow cytometry. We detected that physiological and supra- physiological concentrations of 17b-estradiol and SERM decreased cell growth in esophageal adenocarcinoma cells. In Barrett’s esophagus cells (QhTRT, ChTRT), decreased growth was also detected in response to estrogen/ SERM. The level of estrogen receptor expression in the cell lines correlated with the level of anti-growth effects induced by the receptor agonists. Flow cytometry analysis confirmed estrogen/SERM stimulated apoptosis in esophageal adenocarcinoma cells. Estrogen/SERM treatments were associated with a decrease in the expression of Ki-67 and an increase in E-cadherin expression in esophageal adenocarcinoma cells. This study suggests that esophageal adenocarcinoma and Barrett’s esophagus cells respond to treatment with selective estrogen receptor ligands, resulting in decreased cell growth and apoptosis. Further research to explore potential therapeutic applications is warranted. KEY WORDS: apoptosis, Barrett’s esophagus, esophageal adenocarcinoma, estrogen, tamoxifen raloxifene. INTRODUCTION Clinical and epidemiological data pertinent to esoph- ageal adenocarcinoma demonstrate that this type of cancer arises more frequently in men than women, with a gender ratio of 8–9:1. In addition, men devel- oping esophageal adenocarcinoma have a poorer sur- vival outcome. 1 It has been suggested that the lower incidence of esophageal adenocarcinoma in women might be linked to the higher level of premenopausal estrogen. 1–3 Furthermore, expression of estrogen receptors (ERa and ERb), the major mediators of estrogen effects, have been shown in tissues derived from the mucosa of esophageal cancers. 4,5 Taken together, the evidence from published epidemiological and laboratory studies suggests that estrogen recep- tors could be novel therapeutic targets in the treat- ment of esophageal adenocarcinoma. 3,6 However, this possibility has not been addressed in detail. All previous studies investigating the role of estro- gen in the regulation of esophageal cancer cell growth have been conducted using squamous carcinoma cell lines; KSE-1/2 or ES-25C. 7,8 KSE-1/2 cells had been initially identified as esophageal adenocarcinoma cells but were later confirmed to be squamous cancer lines, 9 rendering studies using these cells irrelevant to ques- tions about esophageal adenocarcinoma. Neverthe- less, a previous study has shown that proliferation of the ER positive KSE-1 esophageal squamous car- cinoma cells is inhibited by 17b-estradiol. 7,8,10 Further- more, in vivo growth of this cell line in both male and female mice is suppressed by 17b-estradiol. 10 A similar finding was seen in another study in which the growth of an ER-positive esophageal squam- ous cancer cell line (ES-25C) was also significantly Address correspondence to: Dr Olga Sukocheva, PhD, Department of Surgery, Flinders Medical Centre, Flinders University, Room 3D211, Bedford Park, SA 5042, Australia. Email: olga.sukocheva@flinders.edu.au Diseases of the Esophagus (2013) 26, 628–635 DOI: 10.1111/dote.12000 © 2012 Copyright the Authors Journal compilation © 2012, Wiley Periodicals, Inc. and the International Society for Diseases of the Esophagus 628 Downloaded from https://academic.oup.com/dote/article/26/6/628/2328899 by guest on 13 June 2023