Telomerase overexpression in K562 leukemia cells protects against apoptosis by serum deprivation and double-stranded DNA break inducing agents, but not against DNA synthesis inhibitors.
Cancer Lett
; 178(2): 187-97, 2002 Apr 25.
Article
em En
| MEDLINE
| ID: mdl-11867204
ABSTRACT
Telomeres are specialized DNA/protein structures that act as protective caps to prevent end fusions. The maintenance of telomeres is essential for chromosomal stability. Telomerase is regulated by human telomerase reverse transcriptase (hTERT). c-Myc oncoprotein is also implicated in the positive regulation of hTERT expression. We show here that two clones of hTERT-transfected K562 erythroleukemia cells have elongated telomeres (22.5 and 24.0 kb), whereas telomere length of both c-Myc-transfected K562 cells and parental K562 cells is 6.5 kb. Telomerase activity and hTERT mRNA expression increased in hTERT-transfected K562 cells, while the expression levels of telomerase activity and hTERT in c-Myc-transfected K562 cells were similar to that in parental K562 cells, despite an overexpression of c-Myc. Importantly, we found that hTERT-transfected K562 cells are protected against apoptosis induced by serum deprivation and double-stranded DNA break inducing agents (ionizing irradiation, and etoposide (VP-16)), but not against DNA synthesis inhibitors (1-beta-D-arabinofuranosylcytosine and hydroxyurea). These findings suggest that overexpression of telomerase by transfecting hTERT confers telomere-elongation and resistance to double-stranded DNA break inducing agents.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Apoptose
/
Telomerase
/
Células K562
Limite:
Humans
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article