Hypermethylation of the human telomerase catalytic subunit (hTERT) gene correlates with telomerase activity

Details

Serval ID
serval:BIB_D4254F107660
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Hypermethylation of the human telomerase catalytic subunit (hTERT) gene correlates with telomerase activity
Journal
International Journal of Cancer
Author(s)
Guilleret  I., Yan  P., Grange  F., Braunschweig  R., Bosman  F. T., Benhattar  J.
ISSN
0020-7136 (Print)
Publication state
Published
Issued date
2002
Volume
101
Number
4
Pages
335-341
Notes
PT - Journal Article PT - Research Support, Non-U.S. Gov't
Abstract
DNA methylation is an epigenetic process involved in embryonic development, differentiation and aging. It is 1 of the mechanisms resulting in gene silencing in carcinogenesis, especially in tumor suppressor genes (e.g., p16, Rb). Telomerase, the DNA polymerase adding TTAGGG repeats to the chromosome end, is involved in the regulation of the replicative life span by maintaining telomere length. This enzyme is activated in germ and stem cells, repressed in normal somatic cells and reactivated in a large majority of tumor cells. The promoter region of the hTERT gene, encoding for the catalytic subunit of human telomerase, has been located in a CpG island and may therefore be regulated at least in part by DNA methylation. We analyzed the methylation status of 27 CpG sites within the hTERT promoter core region by methylation-sensitive single-strand conformation analysis (MS-SSCA) and direct sequencing using bisulfite-modified DNA in 56 human tumor cell lines, as well as tumor and normal tissues from different organs. A positive correlation was observed among hypermethylation of the hTERT promoter, hTERT mRNA expression and telomerase activity (p < 0.00001). Furthermore, this correlation was confirmed in normal tissues where hypermethylation of the hTERT promoter was found exclusively in hTERT-expressing telomerase-positive samples and was absent in telomerase-negative samples (p < 0.00002). Since tumor tissues contain also nonneoplastic stromal elements, we performed microdissection to allow confirmation that the hTERT promoter methylation truly occurred in tumor cells. Our results suggest that methylation may be involved in the regulation of hTERT gene expression. To our knowledge, this is the first gene in which methylation of its promoter sequence has been found to be positively correlated with gene expression
Keywords
DNA Methylation/DNA-Binding Proteins/Gene Expression Regulation,Enzymologic/Humans/Neoplasms/enzymology/Polymorphism,Single-Stranded Conformational/Promoter Regions (Genetics)/RNA,Messenger/analysis/Telomerase/genetics/metabolism/Tumor Cells,Cultured
Pubmed
Web of science
Open Access
Yes
Create date
29/01/2008 18:35
Last modification date
20/08/2019 15:54
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