Short-Term Exposure to Tobacco Toxins Alters Expression of Multiple Proliferation Gene Markers in Primary Human Bronchial Epithelial Cell Cultures

Abstract

The biological effects of only a finite number of tobacco toxins have been studied. Here, we describe exposure of cultures of human bronchial epithelial cells to low concentrations of tobacco carcinogens: nickel sulphate, benzo(b)fluoranthene, N-nitrosodiethylamine, and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). After a 24-hour exposure,EGFRwas expressed in cell membrane and cytoplasm,BCL-2was expressed only in the irregular nuclei of large atypical cells,MKI67was expressed in nuclei with no staining in larger cells, cytoplasmicBIRC5with stronger nuclear staining was seen in large atypical cells, and nuclearTP53was strongly expressed in all cells. After only a 24-hour exposure, cells exhibited atypical nuclear and cytoplasmic features. After a 48-hour exposure,EGFRstaining was localized to the nucleus,BCL-2was slightly decreased in intensity,BIRC5was localized to the cytoplasm, andTP53staining was increased in small and large cells.BCL2L1was expressed in both the cytoplasm and nuclei of cells at 24- and 48-hour exposures. We illustrate that short-termexposure of a bronchial epithelial cell line to smoking-equivalent concentrations of tobacco carcinogens alters the expression of key proliferation regulatory genes,EGFR, BCL-2, BCL2L1, BIRC5, TP53, andMKI67, similar to that reported in biopsy specimens of pulmonary epithelium described to be preneoplastic lesions.