ABSTRACT
To investigate the contribution of beta-catenin to the development of gallbladder carcinoma, genetic alteration in beta-catenin gene, ctnnb-1 and subcellular localization of beta-catenin protein were searched. Mutational analysis of exon 3 in ctnnb-1, which encodes the serine/threonine residues for GSK3beta phosphorylation sites, was performed for 21 gallbladder carcinomas affected with/without the pancreaticobiliary malunion, PBM, and 6 non-cancerous tissues affected with PBM. We also analyzed subcellular localization of beta-catenin protein in all cases immunohistochemically. Nucleotide sequencing analysis revealed that none of them carried mutations that altered amino acid residues in the potential GSK3beta phophorylation sites, but one nucleotide substitution was found. We also analyzed subcellular localization of beta-catenin protein in all cases immunohistochemically, and confirmed its accumulation in both the nucleus and cytoplasm in 10 out of 21 cancer tissues, while the non-cancerous tissues which were affected with PBM and histologically diagnosed as hyperplasia or dysplasia displayed intense membranous staining. A significant correlation between cytoplasmic or nuclear beta-catenin immunoreactivity and clinicopathological status of gallbladder carcinomas was found, especially in the poorer histological differentiation grade(p < 0.05). In conclusion our results suggested that beta-catenin alteration might be a minor contributor to the development of gallbladder carcinomas through abnormal Wnt-wingless signalling, however, decreased membranous expression of beta-catenin might be correlated to carcinoma progression through loss of cell adhesive function in E-cadherin-catenin fashion.
Subject(s)
Cytoskeletal Proteins/genetics , Gallbladder Neoplasms/genetics , Mutation , Trans-Activators/genetics , Adult , Aged , Binding Sites , Cell Differentiation , Cytoskeletal Proteins/metabolism , DNA/metabolism , DNA Mutational Analysis , Female , Gallbladder Neoplasms/metabolism , Gallbladder Neoplasms/pathology , Glycogen Synthase Kinase 3/genetics , Glycogen Synthase Kinase 3 beta , Humans , Immunohistochemistry , Male , Middle Aged , Phosphorylation , Polymorphism, Single-Stranded Conformational , Serine/chemistry , Signal Transduction , Threonine/chemistry , Trans-Activators/metabolism , beta CateninABSTRACT
To investigate the contribution of beta-catenin to the development of carcinoma of the ampulla of Vater, genetic alterations of beta-catenin gene, CTNNB-1 were searched. Mutational analysis of exon3 in CTNNB-1, which encodes the serine/threonine residues for GSK-3beta phosphorylation sites, was performed on 21 cases of carcinoma of the ampulla of Vater, by means of polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) followed by nucleotide sequencing. We found one deleted mutation at codon 32 to approximately 65 in one case of carcinoma of the ampulla of Vater. We also analyzed subcellular localization of beta-catenin protein in all cases immunohistochemically, and confirmed its accumulation in the nucleus in four cases including in a CTNNB-1 mutated one. This is the first study to show CTNNB-1 mutation and beta-catenin expression in carcinoma of the ampulla of Vater. These results suggested that abnormal Wnt-wingless signaling and in particular beta-catenin alteration caused accumulation of beta-catenin, which might partially contribute to the development of carcinoma of the ampulla of Vater.
