Background and aims: Barrett's esophagus, a metaplasia resulting from a long-standing reflux disease, and its progression to esophageal adenocarcinoma (EAC) are characterized by activation of pro-inflammatory pathways, induced by cytokines.
Methods: An in vitro cell culture system representing the sequence of squamous epithelium (EPC1 and EPC2), Barrett's metaplasia (CP-A), dysplasia (CP-B) to EAC (OE33 and OE19) was used to investigate TNF-α-mediated induction of interleukin-8 (IL-8).
Results: IL-6 and IL-8 expressions are increasing with the progression of Barrett's esophagus, with the highest expression of both cytokines in the dysplastic cell line CP-B. IL-8 expression in EAC cells was approx. 4.4-fold (OE33) and eightfold (OE19) higher in EAC cells than in squamous epithelium cells (EPC1 and EPC2). The pro-inflammatory cytokine TNF-α increased IL-8 expression in a time-, concentration-, and stage-specific manner. Furthermore, TNF-α changed the EMT marker profile in OE33 cells by decreasing the epithelial marker E-cadherin and increasing the mesenchymal marker vimentin. The anti-inflammatory compound curcumin was able to repress proliferation and to activate apoptosis in both EAC cell lines.
Conclusion: The increased basal expression levels of IL-8 with the progression of Barrett's esophagus constrain NFκB activation and its contribution in the manifestation of Barrett's esophagus. An anti-inflammatory compound, such as curcumin, could create an anti-inflammatory microenvironment and thus potentially support an increase chemosensitivity in EAC cells.
Keywords: Barrett’s esophagus; EMT; Esophageal adenocarcinoma; Inflammation; TNF-α.