Research Article

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

Figure 4

Immunostaining for BCL-2, EGFR, Ki-67, BCL-XL, p53, and BIRC5 after 24-hr (rows 1 and 3) and 48-hr (rows 2 and 4) exposure to benzo(b)fluoranthene at low concentration. Original magnification 60x. (a) BCL-2. Only nuclei of large atypical cells stain positively for BCL-2 at 24-hour exposure; staining is decreased slightly at 48-hour exposure. Inset: A pyknotic cell (top) and mitotic figure (bottom) stain strongly for Bcl-2. (b) EGFR. EGFR localized to cell membrane, cytoplasm, and weakly to nuclei of all cells at 24-hour exposure; staining shifts to the nuclei at 48-hour exposure, strongly in small cells and weakly in large atypical cells. (c) MKI67, assessed at 24-hr exposure only, strongly stained small cell nuclei with negative staining in large cells. (d) Negative control. Representative image of absence of immunoperoxidase staining. (e) BCL2L1 Similar cytoplasmic and nuclear staining at both 24- and 48-hour exposure. F. TP53. Nuclear staining is noted in nearly all cells at 24-hour exposure, with increased intensity at 48-hour exposure. (g) BIRC5 staining is localized mainly in the cytoplasm of cells following the 24-hour exposure with relatively stronger nuclear staining in large atypical cells. At 48-hour exposure, only cytoplasmic staining is observed with focal membranous staining.
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