Tu1698 EGFR Inhibitors Eliminate Esophageal Cancer Stem Cells by Suppressing Epithelial-Mesenchymal Transition

Abstract

Background: A surplus of reactive oxygen species (ROS) in tissues leads to oxidative stress, resulting in various injurious consequences although ROS plays an important role in normal cellular physiology. As a member of NADPH oxidase family, Duox2 is a major sources of H2O2 for gastrointestinal epithelium. Duox2 expressed in mucosal surfaces is believed as an integral part of host defense system. Duox2 expression was elevated in inflammatory conditions of gastrointestinal and respiratory tracts and human colonic cancer caco-2 cell line. However, the expressions of Duox2 in gastrointestinal cancers are still uncertain. Here we detected the expressions of Duox2 mRNA and protein in the tissues of gastric and colorectal tumors to explore the role of it in the process of gastrointestinal cancers. Methods: The curative tumor tissues from gastric cancer patients (n=30) and colorectal cancer (CRC) patients (n=54) were collected from July 2012 to July 2013 at the first affiliated hospital of Henan university of science and technology. Duox2 protein expressionwas semiquantitatively assessed by immunohistochemical detection in all of both gastric cancer and CRC tissues and their matched normal samples, which were apart away from 5 cm of tumor. Duox2 mRNA expression was evaluated by Real Time PCR (gastric cancer n=16 and CRC n=20). Results: Low level of Duox2 protein expression was found in the epithelium mucosa of gastric and colonic normal tissues, where it was mainly located at the apical membrane in gastric epithelial cells and in the brush border of epithelial cells in colon and rectum. However, the expression of Duox2 protein in both gastric cancer and colorectal cancer were significantly higher than that in each corresponding normal epithelium mucosa (P<0.01). The expression of Duox2 mRNA in gastric cancer and colorectal cancer were also both higher than that in each corresponding normal mucosa (P<0.05). Conclusion: The findings in our study suggested that Duox2might be implicated in the carcinogenesis and development of gastrointestinal cancers via overproduce of ROS.