The interplay of the aryl hydrocarbon receptor and β-catenin alters both AhR-dependent transcription and Wnt/β-catenin signaling in liver progenitors
Jazyk angličtina Země Spojené státy americké Médium print-electronic
Typ dokumentu časopisecké články, práce podpořená grantem
PubMed
21602191
DOI
10.1093/toxsci/kfr129
PII: kfr129
Knihovny.cz E-zdroje
- MeSH
- aromatické hydroxylasy genetika metabolismus MeSH
- beta-katenin genetika metabolismus MeSH
- buněčná adheze MeSH
- buněčná diferenciace MeSH
- buněčné linie MeSH
- cytochrom P-450 CYP1A1 genetika metabolismus MeSH
- cytochrom P450 CYP1B1 MeSH
- down regulace účinky léků MeSH
- hepatocyty účinky léků MeSH
- játra účinky léků MeSH
- kadheriny genetika MeSH
- krysa rodu Rattus MeSH
- polychlorované dibenzodioxiny toxicita MeSH
- potkani inbrední F344 MeSH
- proteiny Wnt genetika metabolismus MeSH
- receptory aromatických uhlovodíků genetika metabolismus MeSH
- signální dráha Wnt MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- aromatické hydroxylasy MeSH
- beta-katenin MeSH
- Cyp1b1 protein, rat MeSH Prohlížeč
- cytochrom P-450 CYP1A1 MeSH
- cytochrom P450 CYP1B1 MeSH
- kadheriny MeSH
- polychlorované dibenzodioxiny MeSH
- proteiny Wnt MeSH
- receptory aromatických uhlovodíků MeSH
β-catenin is a key integrator of cadherin-mediated cell-cell adhesion and transcriptional regulation through the Wnt/β-catenin pathway, which plays an important role in liver biology. Using a model of contact-inhibited liver progenitor cells, we examined the interactions of Wnt/β-catenin signaling with the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, which mediates the toxicity of dioxin-like compounds, including their effects on development and hepatocarcinogenesis. We found that AhR and Wnt/β-catenin cooperated in the induction of AhR transcriptional targets, such as Cyp1a1 and Cyp1b1. However, simultaneously, the activation of AhR led to a decrease of dephosphorylated active β-catenin pool, as well as to hypophosphorylation of Dishevelled, participating in regulation of Wnt signaling. A sustained AhR activation by its model ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), led to a downregulation of a number of Wnt/β-catenin pathway target genes. TCDD also induced a switch in cytokeratin expression, where downregulation of cytokeratins 14 and 19 was accompanied with an increased cytokeratin 8 expression. Together with a downregulation of additional markers associated with stem-like phenotype, this indicated that the AhR activation interfered with differentiation of liver progenitors. The downregulation of β-catenin was also related to a reduced cell adhesion, disruption of E-cadherin-mediated cell-cell junctions and an increased G1-S transition in liver progenitor cell line. In conclusion, although β-catenin augmented the expression of selected AhR target genes, the persistent AhR activation may lead to downregulation of Wnt/β-catenin signaling, thus altering differentiation and/or proliferative status of liver progenitor cells.
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