Search

Background: Aspartyl (asparaginyl) β-hydroxylase (AAH) is an α-ketoglutarate-dependent dioxygenase that hydroxylates aspartate and asparagine residues in EGF-like domains of proteins. The consensus sequence for AAH β-hydroxylation occurs in signaling molecules such as Notch and Notch homologs, which have roles in cell migration.Aim: This study evaluated the potential role of AAH in cell migration using cholangiocarcinoma cell lines as models due to their tendency to widely infiltrate the liver.Methods: Five human cholangiocarcinoma cell lines established from human tumors were examined for AAH expression and motility. The effect of antisense oligodeoxynucleotide inhibition of AAH on cholangiocarcinoma cell migration was investigated.Results: Western blot analysis detected the ∼86 kDa AAH protein in all five cholangiocarcinoma cell lines, and higher levels of AAH in cell lines derived from moderately or poorly differentiated compared with well-differentiated tumors. Immunocytochemical staining and fluorescence activated cell sorting analysis revealed both surface and intracellular AAH immunoreactivity. Using the phagokinetic non-directional migration assay and a novel ATPLite luminescence-based directional migration assay, we correlated AAH expression with motility. Correspondingly, antisense and not sense or mutated antisense AAH oligodeoxynucleotides significantly inhibited AAH expression and motility in cholangiocarcinoma cells.Conclusions: AAH over-expression may contribute to the infiltrative growth pattern of cholangiocarcinoma cells by promoting motility. [Copyright &y& Elsevier]