Conversion of metaplastic Barrett's epithelium into post-mitotic goblet cells by gamma-secretase inhibition.

Barrett's esophagus (BE) affects approximately 2% of the Western population and progresses to esophageal adenocarcinoma (EAC) in 0.5% of these patients each year. In BE, the stratified epithelium is replaced by an intestinal-type epithelium owing to chronic gastroduodenal reflux. Since self-renewal of intestinal crypts is driven by Notch signaling, we investigated whether this pathway was active in the proliferative crypts of BE. Immunohistochemistry confirmed the presence of an intact and activated Notch signaling pathway in metaplastic BE epithelium, but not in the normal human esophagus. Similar observations were made in two well-known human Barrett's-derived EAC cell lines, OE33 and SKGT-5. We then sought to investigate the effects of Notch inhibition by systemic treatment with a gamma-secretase inhibitor in a well-validated rodent model for BE. As we have shown previously in normal intestinal epithelium, Notch inhibition converted the proliferative Barrett's epithelial cells into terminally differentiated goblet cells, whereas the squamous epithelium remained intact. These data imply that local application of gamma-secretase inhibitors may present a simple therapeutic strategy for this increasingly common pre-malignant condition.