Cigarette smoke extract induces DNA damage but not apoptosis in human bronchial epithelial cells.
Am J Respir Cell Mol Biol
; 33(2): 121-9, 2005 Aug.
Article
en En
| MEDLINE
| ID: mdl-15845867
ABSTRACT
Whether DNA damage caused by cigarette smoke leads to repair or apoptosis has not been fully elucidated. The current study demonstrates that cigarette smoke induces single-strand DNA damage in human bronchial epithelial cells. Cigarette smoke also stimulated caspase 3 precursors as well as intact poly (ADP-ribose) polymerase (PARP) production, but did not activate caspase 3 or cleave PARP, while the alkaloid camptothecin did so. Neither apoptosis nor necrosis was induced by cigarette smoke when the insult was removed within a designated time period. In contrast, DNA damage following cigarette smoke exposure was repaired as evidenced by decreasing terminal dUTP-biotin nick-end labeling positivity. The PARP inhibitor, 3-aminobenzamide blocked this repair. Furthermore, cells subjected to DNA damage were able to survive and proliferate clonogenically when changed to smoke-free conditions. These results suggest that cigarette smoke-induced DNA damage in bronchial epithelial cells is not necessarily lethal, and that PARP functions in the repair process. Our data also suggest that the potency of cigarettes as a carcinogen may result from their ability to induce DNA damage while failing to trigger the apoptotic progression permitting survival of cells harboring potentially oncogenic mutations.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Humo
/
Nicotiana
/
Daño del ADN
/
Bronquios
/
Apoptosis
Límite:
Humans
Idioma:
En
Revista:
Am J Respir Cell Mol Biol
Asunto de la revista:
BIOLOGIA MOLECULAR
Año:
2005
Tipo del documento:
Article
País de afiliación:
Estados Unidos