Stem cell marker prominin-1/AC133 is expressed in duct cells of the adult human pancreas

Objectives: Many efforts are spent in identifying stem cells in adult pancreas because these could provide a source of A cells for cell-based therapy of type 1 diabetes. Prominin-1, particularly its specific glycosylation-dependent AC133 epitope, is expressed on stem/progenitor cells of various human tissues and can be used to isolate them. We, therefore, examined its expression in adult human pancreas. Methods: To detect prominin-1 protein, monoclonal antibody CD133/1 (AC133 clone), which recognizes the AC133 epitope, and the alpha hE2 antiserum, which is directed against the human prominin-1 polypeptide, were used. Prominin-1 RNA expression was analyzed by real-time polymerase chain reaction. Results: We report that all duct-lining cells of the pancreas express prominin-1. Most notably, the cells that react with the alpha hE2 antiserum also react with the AC133 antibody. After isolation and culture of human exocrine cells, we found a relative increase in prominin-1 expression both at protein and RNA expression level, which can be explained by an enrichment of cells with ductal phenotype in these cultures. Conclusions: Our data show that pancreatic duct cells express prominin-1 and surprisingly reveal that its particular AC133 epitope is not an exclusive stem and progenitor cell marker.