Aberrant signalling activities of beta-catenin, originally identified as a component of cell-adhesion complexes, are now considered to be an important factor in colorectal carcinogenesis. However, recently it was shown that also gamma- as well as p120 catenins have a dual role either in cell adhesion or in affecting some gene activation. Therefore, the levels and interactions of these three catenins in human colorectal carcinoma cell lines were analysed. A great heterogeneity in the expression of all catenins tested was found in colorectal carcinoma cell lines HT29 and LS174T. Detailed analysis of beta-catenin interactions was done. GST-APC fragment-fused proteins were used to absorb beta-catenin and its complexes from cell lysates. Similarly, the E-cadherin binding capacity of the residual pool of beta-catenin was analysed using the GST-ECT construct. It was found that the level of beta-catenin does not necessarily depend either on the APC or beta-catenin gene mutations and that co-precipitation of beta-, gamma-, and p120 catenins is not limited to cells that express E-cadherin.

• MeSH
• beta-katenin MeSH
• buňky HT-29 MeSH
• cytoskeletální proteiny metabolismus   MeSH
• delta-katenin MeSH
• desmoplakiny MeSH
• fosfoproteiny metabolismus   MeSH
• kadheriny metabolismus   MeSH
• kateniny MeSH
• kolorektální nádory metabolismus   patologie   MeSH
• kompetitivní vazba MeSH
• lidé MeSH
• molekuly buněčné adheze metabolismus   MeSH
• nádorové buňky kultivované MeSH
• precipitinové testy MeSH
• trans-aktivátory * MeSH
• vazba proteinů MeSH
• western blotting MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• beta-katenin MeSH
• CTNNB1 protein, human MeSH Prohlížeč
• cytoskeletální proteiny MeSH
• delta-katenin MeSH
• desmoplakiny MeSH
• fosfoproteiny MeSH
• kadheriny MeSH
• kateniny MeSH
• molekuly buněčné adheze MeSH
• trans-aktivátory * MeSH

BACKGROUND & AIMS: The Wnt signaling pathway is required for maintenance of the intestinal epithelia; blocking this pathway reduces the proliferative capacity of the intestinal stem cells. However, aberrant Wnt signaling leads to intestinal cancer. We investigated the roles of the Wnt pathway in homeostasis of the intestinal epithelium and during malignant transformation in human cells and mice. METHODS: We performed chromatin immunoprecipitation (ChIP) with DNA microarray analysis (ChIP-on-chip) to identify genes regulated by Wnt signaling in human colorectal cancer cells Colo320, DLD1, LS174T, and SW480. Formation of intestinal tumor was induced in C57BL/6J mice using azoxymethane and dextran sulfate. Intestinal tissues from these mice, as well as Apc(+/Min) and Apc(CKO/CKO)/Lgr5-EGFP-IRES-CreERT2 mice, were analyzed by immunohistochemistry and in situ hybridization. RESULTS: We identified promoter regions of 960 genes that interacted with the Wnt pathway nuclear effector T-cell factor 4 in 4 different human colorectal cancer-derived cell lines; 18 of these promoters were present in all chromatin precipitates. Wnt signaling up-regulated a member of the tumor necrosis factor receptor superfamily called TROY. Levels of TROY messenger RNA were increased in human cells with deficiencies in the adenomatous polyposis coli (APC) gene and in cells stimulated with the Wnt3a ligand. Expression of Troy was significantly up-regulated in neoplastic tissues from mice during intestinal tumorigenesis. Lineage tracing experiments revealed that Troy is produced specifically by fast-cycling intestinal stem cells. TROY associated with a unique marker of these cells, leucine-rich repeat-containing G-protein coupled receptor (LGR) 5. In organoids established from the intestinal crypts, Troy suppressed signaling mediated by R-spondin, a Wnt agonist. CONCLUSIONS: TROY is up-regulated in human colorectal cancer cell lines and in intestinal tumors in mice. It functions as a negative modulator of the Wnt pathway in LGR5-positive stem cells.

• MeSH
• apoptóza MeSH
• experimentální nádory MeSH
• hybridizace in situ MeSH
• imunohistochemie MeSH
• kolorektální nádory genetika   metabolismus   patologie   MeSH
• lidé MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• nádorová transformace buněk genetika   metabolismus   patologie   MeSH
• nádorové buněčné linie MeSH
• nádorové kmenové buňky metabolismus   patologie   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• proliferace buněk MeSH
• receptory spřažené s G-proteiny fyziologie   MeSH
• receptory TNF fyziologie   MeSH
• regulace genové exprese u nádorů * MeSH
• RNA nádorová genetika   MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• signální dráha Wnt fyziologie   MeSH
• střevní sliznice metabolismus   patologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• Lgr5 protein, mouse MeSH Prohlížeč
• receptory spřažené s G-proteiny MeSH
• receptory TNF MeSH
• RNA nádorová MeSH
• Tnfrsf19 protein, mouse MeSH Prohlížeč