FILTERED, TAR-FREE AND AEROSOL-FREE CIGARETTE-SMOKE CAUSES ACCUMULATION OF THE TUMOR-SUPPRESSOR PROTEIN P53 IN RODENT CELLS
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- Published online on: December 1, 1994 https://doi.org/10.3892/ijo.5.6.1405
- Pages: 1405-1409
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Abstract
Cigarette smoke was filtered with a Cambridge glass fiber filter retaining 99.9% of the tar and aerosol fraction and diluted 1:5 with air. The murine cell line L929 was exposed to this smoke preparation for periods of up to 10 min. Thereafter the following parameters were determined at different times: Nuclear accumulation of the tumor suppressor protein p53 indicating chromatin injury (by immunostaining); apoptotic DNA fragmentation (by DNA end labelling with biotin-16-dUTP in the presence of terminal deoxyribonucleotidyl transferase); the intracellular level of reactive oxygen intermediates (ROI) (by cytofluorimetry with the fluorigenic stain 2',7'-dichlorofluorescin diacetate). After 1 min exposure to 1:5 air-diluted filtered cigarette smoke maximal p53 accumulation occured about 20 h later, whereas maximal DNA fragmentation and apoptosis and maximal ROI levels were found after 10 min of exposure. Obviously, even the diluted, tar- and aerosol-free fraction of cigarette smoke has the potency, after 1 min of exposure only, to exert severe DNA damage, a potential transformation risk for the surviving cell fraction, in murine cell cultures as indicated by stabilization and accumulation of the tumor suppressor protein p53.