The effect of ATM kinase inhibition on the initial response of human dental pulp and periodontal ligament mesenchymal stem cells to ionizing radiation.
Int J Radiat Biol
; 89(7): 501-11, 2013 Jul.
Article
em En
| MEDLINE
| ID: mdl-23425510
ABSTRACT
PURPOSE:
This study evaluates early changes in human mesenchymal stem cells (MSC) isolated from dental pulp and periodontal ligament after γ-irradiation and the effect of ataxia-telangiectasia mutated (ATM) inhibition.METHODS:
MSC were irradiated with 2 and 20 Gy by (60)Co. For ATM inhibition, specific inhibitor KU55933 was used. DNA damage was measured by Comet assay and γH2AX detection. Cell cycle distribution and proteins responding to DNA damage were analyzed 2-72 h after the irradiation.RESULTS:
The irradiation of MSC causes an increase in γH2AX; the phosphorylation was ATM-dependent. Irradiation activates ATM kinase, and the level of p53 protein is increased due to its phosphorylation on serine15. While this phosphorylation of p53 is ATM-dependent in MSC, the increase in p53 was not prevented by ATM inhibition. A similar trend was observed for Chk1 and Chk2. The increase in p21 is greater without ATM inhibition. ATM inhibition also does not fully abrogate the accumulation of irradiated MSC in the G2-phase of the cell-cycle.CONCLUSIONS:
In irradiated MSC, double-strand breaks are tagged quickly by γH2AX in an ATM-dependent manner. Although phosphorylations of p53(ser15), Chk1(ser345) and Chk2(thr68) are ATM-dependent, the overall amount of these proteins increases when ATM is inhibited. In both types of MSC, ATM-independent mechanisms for cell-cycle arrest in the G2-phase are triggered.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Ligamento Periodontal
/
Proteínas Serina-Treonina Quinases
/
Proteínas de Ciclo Celular
/
Proteínas Supressoras de Tumor
/
Polpa Dentária
/
Proteínas de Ligação a DNA
/
Células-Tronco Mesenquimais
Limite:
Humans
Idioma:
En
Revista:
Int J Radiat Biol
Assunto da revista:
RADIOLOGIA
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
República Tcheca