Radiofrequency Ablation for Dysplasia in Barrett’s Esophagus Restores β-Catenin Activation Within Esophageal Progenitor Cells

Background and Aims Endoscopic therapies for Barrett’s esophagus (BE) associated dysplasia, particularly radiofrequency ablation (RFA), are popular alternatives to surgery. The effect of such therapies on dysplastic stem/progenitor cells (SPC) is unknown. Recent studies suggest that AKT phosphorylation of β-Catenin occurs in SPCs and may be a marker of activated SPCs. We evaluate the effect of RFA in restoring AKT-mediated β-Catenin signaling in regenerative epithelium. Methods Biopsies were taken from squamous, non-dysplastic BE, dysplastic BE and esophageal adenocarcinoma (EAC). Also, post-RFA, biopsies of endoscopically normal appearing neosquamous epithelium were taken at 3, 6, and 12 months after successful RFA. Immunohistochemistry and Western blot analysis was performed for Pβ-Catenin 552 (Akt-mediated phosphorylation of β-Catenin), Ki-67 and p53. Results There was no difference in Pβ-Catenin552 in squamous, GERD, small bowel and non-dysplastic BE. There was a fivefold increase in Pβ-Catenin 552 in dysplasia and EAC compared to non-dysplastic BE ( P < 0.05). Also, there was a persistent threefold increase in Pβ-Catenin 552 in neosquamous epithelium 3 months after RFA compared to native squamous epithelium ( P < 0.05) that correlated with increased Ki-67. Six months after RFA, Pβ-Catenin 552 and Ki-67 are similar to native squamous epithelium. Conclusions Enhanced AKT-mediated β-Catenin activation is seen in BE-associated carcinogenesis. Three months after RFA, squamous epithelial growth from SPC populations exhibited increased levels of Pβ-Catenin 552 . This epithelial response becomes quiescent at 6 months after RFA. These data suggest that elevated Pβ-Catenin 552 after RFA denotes a repair response in the neosquamous epithelium 3 months post-RFA.