Asbestos induces nuclear factor kappa B (NF-kappa B) DNA-binding activity and NF-kappa B-dependent gene expression in tracheal epithelial cells.
Janssen-YM; Barchowsky-A; Treadwell-M; Driscoll-KE; Mossman-BT
Proc Natl Acad Sci U.S.A. 1995 Aug; 92(18):8458-8462
The effects of asbestos (1332214) on nuclear-factor-kappa-B (NF- kappa-B) DNA binding activity and NF-kappa-B dependent gene expression were examined. Hamster tracheal epithelial (HTE) cells were cultured with crocidolite (12001284) concentrations of 1.25 or 5 micrograms per square centimeter (microg/cm2) for up to 24 hours. Following exposure, nuclear protein extracts were analyzed for enhanced NF-kappa-B DNA binding activity using a gel mobility shift assay. Transfection studies using the calcium phosphate coprecipitation technique were conducted in order to measure NF- kappa-B dependent gene expression. Messenger RNA (mRNA) levels of c- myc, a gene regulated by NF-kappa-B, were determined via Northern blot analysis. Multiple gel shift complexes, competitively blocked by excesses of NF-kappa-B, were observed in the nuclear protein extracts of crocidolite exposed HTE cells. Antibodies recognizing the p50 and p65 members of the NF-kappa-B family also reduced the formation of gel shift complexes. Crocidolite exposure caused a dose dependent increase in complex formation. Pretreatment of HTE cells with N-acetyl-L-cysteine, a glutathione stimulator, induced a significant decrease in the crocidolite induced NF-kappa-B DNA binding activity. The expression of NF-kappa-B dependent genes was increased in HTE cells transfected with an NF-kappa-B consensus sequence and exposed to lipopolysaccharide for 4 or 16 hours or crocidolite for 16 hours. Levels of c-myc mRNA were significantly elevated in HTE cells exposed to crocidolite for 4 to 24 hours. The authors conclude that asbestos induces NF-kappa-B DNA binding activity and NF-kappa-B dependent gene expression, both of which may be involved in the development of asbestos induced lung cancers.
NIOSH-Publication; NIOSH-Grant; Pulmonary-system-disorders; Cell-cultures; Asbestos-fibers; Exposure-levels; Dose-response; Genetic-factors; Deoxyribonucleic-acids; Ribonucleic-acids; Lung-cells
Pharmacology and Toxicology Dartmouth Medical School Remsen 7650 Hanover, NH 03755-3835
Proceedings of the National Academy of Sciences of the United States of America
Dartmouth College, Hanover, New Hampshire