Abstract
The methylation status of the rat gamma-glutamyl transpeptidase (GGT) gene was investigated during liver development and hepatocarcinogenesis. The analysis with the restriction enzymes MspI/HpaII revealed that, during ontogeny, there is a progressive methylation of the GGT gene that coincides with a progressive decrease in GGT activity. Thus, there is an inverse correlation between methylation and expression of the GGT gene, suggesting a role for DNA methylation in the regulation of the gene during normal differentiation. The methylation patterns of the GGT gene in liver tumours induced by aflatoxin B1 exhibit heterogeneity. Nevertheless, a band of 5.7 KB was observed in all the DNA samples from aflatoxin B1-induced tumours which was not present in control liver DNA. The specificity of the DNA methylation changes was assessed using nafenopin, which induces hepatic tumours without elevation of GGT activity. We conclude that, during hepatocarcinogenesis, there is a modification of the DNA methylation pattern of the GGT gene, but there is no simple correlation with GGT activity. In no case was the GGT gene methylation in hepatocarcinogenesis found to be equivalent to the pattern observed in fetal liver. Thus if methylation is involved in the regulation of GGT gene transcription, the mechanisms must be different in fetal liver and hepatocarcinoma.
Original language | English |
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Pages (from-to) | 1035-1040 |
Number of pages | 6 |
Journal | Carcinogenesis |
Volume | 12 |
Issue number | 6 |
DOIs | |
Publication status | Published - 1991 Jun |
Externally published | Yes |
Bibliographical note
Funding Information:The authors would like to thank Dr A.G Smith and Dr B.G.Lake for providing tissue samples from hexachlorobenzene-, diethylnitrosamine-and nafenopin-treated animals and for helpful discussions. We thank Dr Y.Laperche and Dr R.Barouki for their most helpful comments and L.Rosario and E.Grandvilliers for their skilful secretarial assistance. Susan Griffiths was funded by the Association for International Cancer Research. This work was supported by the CNAMTS.
Copyright:
Copyright 2010 Elsevier B.V., All rights reserved.
ASJC Scopus subject areas
- Cancer Research