Jc. Willey et al., XENOBIOTIC METABOLISM ENZYME GENE-EXPRESSION IN HUMAN BRONCHIAL EPITHELIAL AND ALVEOLAR MACROPHAGE CELLS, American journal of respiratory cell and molecular biology, 14(3), 1996, pp. 262-271
Human bronchial epithelial cells (BEC), a primary defense against inha
led materials, are the progenitor cells for bronchogenic carcinomas an
d have important metabolic capabilities. We used reverse transcriptase
-polymerase chain reaction (RT-PCR) to identify xenobiotic metabolism
enzymes expressed in primary BEC and alveolar macrophages (AM) of non-
smoking volunteers. Cytochromes P450 (CYP) 1A1, 1B1, 2B7, 2E1, and 4B1
and microsomal epoxide hydrolase (mEH) were expressed in BEC but not
AM. CYP2F1 was expressed in BEC, but it was expressed at barely detect
able levels or not at all in AM. NADPH oxidoreductase (NADPH OR), micr
osomal glutathione transferase (GST 12), glutathione transferase mu, p
henol sulfouansferase (PST), thermolabile phenol sulfotransferase (TL
PST), and the clara cell-specific gene, CC10 were expressed in both BE
C and AM. CYP3A4 and glucuronosyl transferases-1 and 2 were not expres
sed in either BEC or AM. In contrast to primary BEC, of the genes eval
uated, the immortalized human bronchial epithelial cell line BEP2D con
stitutively expressed only CYP1A1, CYP2E1, NADPH OR, glucuronosyl tran
sferase 1, GST 12, GST mu, PST, TL PST, and CC10. The loss of xenobiot
ic metabolism enzyme gene expression in the BEP2D cell line may result
from either reduced exposure to inducing agents, or loss of different
iative characteristics in culture. It is clear from the data comparing
BEC and AM that there are important intertissue differences in expres
sion of xenobiotic metabolism enzymes.