| Summary: | 碩士 === 國立臺灣大學 === 毒理學研究所 === 92 === The emissions of motorcycle exhaust are a major source of environmental pollutants in urban areas of Taiwan. Motorcycle exhaust particulates (MEP) contain carcinogenic polycyclic aromatic hydrocarbons including benzo[a]pyrene（BaP）. This study has determined the ability of MEP to alter the expression profiles of carcinogen- and estrogen-metabolizing genes, oncogenes, tumor suppressor genes in female lung adenocarcinoma CL5 cells treated with 100 μ�慊/ml organic extracts of MEP for 6 hr. cDNA microarray studies were carried out and gene expression changes were confirmed. The results showed that for metabolic genes, MEP extracts increased the mRNA levels of carcinogen- and estrogen-metabolizing enzymes cytochrome P450 (CYP) 1A1 and CYP1B1. For oncogenes and tumor suppressor genes, MEP increased the expression of oncogene fra and tumor suppressor p21. For cytokines and growth factors, MEP increased the expression of interleukin (IL)-1? IL-6, IL-11, fibroblast growth factor (FGF)-6, FGF-9 and vascular endothelial growth factor (VEGF)-D. Treatment of CL5 cells with 10 μM benzo(a)pyrene altered gene expression profiles in a manner similar to MEP. Induction of CYP1A1,CYP1B1, IL-1? IL-6, FGF-9 and VEGF-D by treatment with MEP or BaP was suppressed by cotreatment with MEP or BaP and aryl hydrocarbon receptor antagonist ��-naphthoflavone. Induction of IL-1? IL-6, FGF-9 and VEGF-D by treatment with MEP or BaP was suppressed by cotreatment with MEP or BaP and antioxidant N-acetylcysteine. The FGF-9 protein in CL5 microsomes was increased by treatment with 100 μg/ml MEP or 10 μM BaP for 24 hours. In bioactivity studies, CL5 cells were treated with 100 μg/ml MEP extract or 10 μM BaP for 24 hr and cell medium was collected to treat human lung fibroblast WI-38. Treatment with CL5 medium for 4 days, produced a 30% increase in the growth of WI-38 cells. In low invasive ability human lung adenocarcinoma CL1-0 and high invasive ability CL1-5 cells, MEP induced FGF-9 mRNA expression in CL1-5 more than CL1-0 cells. In animal studies, female and male Wistar rats were exposed to 1:10 diluted ME for 4 weeks. The ME inhalation treatment resulted in a 2-fold increase of FGF-9 mRNA in female rat lungs, but not in male lungs. FGF-9 mRNA expression in female and male rat liver was lower than the mRNA level in lung and ME inhalation had no marked effects on liver FGF-9. ME inhalation exposure had no effects on ovaries and uterus. These differential data suggested that the expression and ME induction of FGF-9 gene showed gender and tissue variability. These results demonstrate that MEP has the ability to induce multiple genes of carcinogen-activation, inflammatory cytokine, and growth factor families in female lung-derived cells. ME inhalation exposure is an inducer of FGF-9 gene expression in female rat lungs. These results suggest that exposure to ME may present an environmental factor contributing to increased risk for lung cancer. FGF-9 may serve as an important tool to study the role of gene-environment interaction in female lung adenocarcinoma.
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