Ezrin-Radixin-Moesin-Binding Phosphoprotein (EBP50), an Estrogen-Inducible Scaffold Protein, Contributes to Biliary Epithelial Cell Proliferation

Abstract

Ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50) anchors and regulates apical membrane proteins in epithelia. EBP50 is inducible by estrogen and may affect cell proliferation, although this latter function remains unclear. The goal of this study was to determine whether EBP50 was implicated in the ductular reaction that occurs in liver disease. EBP50 expression was examined in normal human liver, in human cholangiopathies (ie, cystic fibrosis, primary biliary cirrhosis, and primary sclerosing cholangitis), and in rats subjected to bile-duct ligation. The regulation of EBP50 by estrogens and its impact on proliferation were assessed in both bile duct-ligated rats and Mz-Cha-1 human biliary epithelial cells. Analyses of cell isolates and immunohistochemical studies showed that in normal human liver, EBP50 is expressed in the canalicular membranes of hepatocytes and, together with ezrin and cystic fibrosis transmembrane conductance regulator, in the apical domains of cholangiocytes. In both human cholangiopathies and bile duct-ligated rats, EBP50 was redistributed to the cytoplasmic and nuclear compartments. EBP50 underwent a transient increase in rat cholangiocytes after bile-duct ligation, whereas such expression was down-regulated in ovariectomized rats. In addition, in Mz-Cha-1 cells, EBP50 underwent upregulation and intracellular redistribution in response to 17␤-estradiol, whereas its proliferation was inhibited by siRNA-mediated EBP50 knockdown. These results indicate that both the expression and distribution of EBP50 are regulated by estrogens and contribute to the proliferative response in biliary epithelial cells. (Am J

EBP50 gene transfection promotes 5-fluorouracil-induced apoptosis in gastric cancer cells through Bax- and Bcl-2-triggered mitochondrial pathways

“…They found that EBP50 overexpression is significantly associated with tumor stage, metastatic progression, poor prognosis and ER status (5,9). The expression and distribution of EBP50 are regulated by estrogens and contribute to the proliferative response in biliary epithelial cells (10). We discovered that EBP50 is a novel marker for gastric adenocarcinoma and is involved in the proliferation, migration, and invasion of gastric cancer cells.…”

Ezrin-Radixin-Moesin-binding Phosphoprotein 50 (EBP50) and Nuclear Factor-κB (NF-κB)

“…The up-regulation of EBP50 has been reported in multiple disease states including hepatocellular carcinomas, cholangiopathies, glioblastoma, breast cancer, psoriasis, and vascular injury (21,(32)(33)(34)(35)(36)(37). However, little is known about the transcriptional regulation of EBP50 expression in normal and disease states.…”

Loss of EBP50 stimulates EGFR activity to induce EMT phenotypic features in biliary cancer cells

“…Real-time reverse transcription-polymerase chain reaction (RT-PCR) was performed as described previously (Fouassier et al, 2009). Briefly, total RNA was extracted from cultured cells and used for reverse transcription with 200 U of Moloney murine leukemia virus reverse transcriptase (Invitrogen) for 1 h at 37 1C.…”

“…Immunofluorescence Immunofluorescence was performed as described previously (Fouassier et al, 2009). Briefly, cells were fixed in 4% paraformaldehyde for 15 min, permeabilized in 0.1% SurfactAmps X100 (Thermo Scientific, Rockford, IL, USA) for 10 min and blocked with 1% albumin and 10% goat serum for 1 h at room temperature.…”

“…Abnormal expression of scaffold proteins has been linked to different types of cancer in human (Claperon and Therrien, 2007). Ezrin-radixinmoesin-(ERM)-binding phosphoprotein 50 (EBP50; also named NHERF-1 for Na þ /H þ exchanger regulatory factor-1) is a scaffold protein that is strongly expressed in the liver, and in particular beneath the plasma membrane of biliary epithelial cells (Fouassier et al, 2001(Fouassier et al, , 2009. Previous studies have suggested that EBP50 could also form protein complexes at the adherens junctions (AJs), by directly interacting with b-catenin (Shibata et al, 2003;Kreimann et al, 2007).…”