These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Differential expression of glutamine synthetase and cytochrome P450 isoforms in human hepatoblastoma.
    Author: Schmidt A, Braeuning A, Ruck P, Seitz G, Armeanu-Ebinger S, Fuchs J, Warmann SW, Schwarz M.
    Journal: Toxicology; 2011 Mar 15; 281(1-3):7-14. PubMed ID: 21237236.
    Abstract:
    Carcinogenesis is often linked to aberrant activation of Wnt/β-catenin signalling, in many cases caused by activating CTNNB1 mutations (encoding β-catenin). Recently, β-catenin was established as a decisive regulator of hepatic glutamine synthetase (GS) and cytochrome P450 (CYP) expression in mouse hepatocarcinogenesis. This study was aimed to analyse the connection of β-catenin signalling and GS/CYP expression in human paediatric tumours. Samples from 23 paediatric tumours were analysed for activating mutations in CTNNB1. Protein expression of the model β-catenin target GS and of various CYP isoforms was analysed and correlated with CTNNB1 mutational status and histological findings. Activating CTNNB1 mutations were frequent in hepatoblastoma (80%) and nephroblastoma (31%). In CTNNB1-mutated hepatoblastoma, expression of GS was only detected in tumour areas with epithelial, not with mesenchymal differentiation. Particularly high expression of glutamine synthetase was found in hepatoblastoma cells directly neighbouring a mesenchymal-type tumour area or stroma cells, associated with above-average cell proliferation. GS expression was not observed in CTNNB1-mutated nephroblastoma. Hepatoblastoma with activated β-catenin expressed different CYPs relevant for the metabolism of cytostatic drugs, but with high interindividual variance and heterogeneity within a single tumour. GS and different CYPs are co-expressed in hepatoblastoma with activated β-catenin. Moreover, other factors like histological subtype of tumour cells and cell-cell-interactions at the borders between different areas of the tumours affect expression of these β-catenin target genes. Analysis of CYP expression in resected tumour tissue might be useful for the selection of appropriate cytostatics for post-operative chemotherapy.
    [Abstract] [Full Text] [Related] [New Search]