| Abstract: | 近年來,肺癌為我國惡性腫瘤死因之首,華裔婦女雖然吸菸率低,卻具有較高的肺癌發病率。許多流行病學調查結果顯示,華裔人群中可能存在一些共同導致肺癌的危險因子。室內空氣汙染是肺癌非吸煙危險因素研究中的一個重要課題,烹調煙霧作為肺癌的危險因素在近年來受到人們的關注。烹調煙霧包括食物烹調煙霧及食用油煙霧,吸入食物烹調煙霧及食用油煙霧對人的肺功能有明顯影響。已有研究報告指出,食用油煙霧對細菌具有致突變性。因此,針對食用油加熱後所產生的煙霧可能具有遺傳毒性。 許多基因毒物,已被證實除了造成基因損傷之外,亦能活化訊息傳遞途徑,誘導某些Oncogenes、Growth factors等基因表現,這些基因表現已被證實與細胞分裂、分化、生物體免疫反應、甚致癌化過程有關。因此,本計畫探討食用油煙霧於人類肺癌細胞株的毒性及誘導那些基因表現。 首先我們分析食用油煙萃取物中的化學成分,發現大部分是游離的脂肪酸及其裂解產物。當肺癌細胞株CL3暴露食用油煙萃取物後,對細胞生長並無顯著影響。當我們進一步以RT-PCR方法檢測各種基因表現程度時發現:CL3細胞暴露食用油煙萃取物後Cytochrome P4501A1與1B1等基因表現程度於4小時內短暫增加為對照組的2至4倍;Cytochrome P4502E1基因表現程度於24小時後增為2倍;Tumor growth factor .beta.1基因表現程度於24小時後增為對照組的4倍。Cytokines包括IL-2、IL-4、IL-6、IL-13、Interferon-.gamma.、Tumor necrosis factor-.alpha.等基因表現程度並無明顯改變。 由本研究結果可知,人類肺癌細胞株暴露食用油煙萃取物後雖然不會影響細胞生長,但能增加Cytochrome P450s與Tumor growth factor .beta.1等基因表現。
Lung cancer is the leading cause of death from cancer in female and the second one in male Taiwanese population. Chinese women had much lower rates of smoking, but higher mortality rates among female nonsmokers than women in the west world. Epidemiological studies among Chinese women from Hong Kong, Singapore and the United States indicated that there may be common risk factors causing lung cancer in this population. Indoor pollution, such as cooking oil fume, has been considered as an important risk factor for lung cancer. Inhalation of cooking oil fume had been shown to effect normal pulmonary function. In addition, cooking oil fumes was mutagenic as determined by the Ames test. Recently many genotoxic agents have been shown to cause DNA damage as well as to alter gene expression, such as cytokines and growth factors. These genes were suggested to participate in cell proliferation, differentiation, inflammation and even carcinogenesis. In the present study we'd like to examine whether cooking oil fume may alter these genes expression in human lung cells. First, we analyze the components in the cooking oil fumes. Majority of them were free acids and their degraded products. When human lung adenocarcinoma CL3 cells were exposed to the cooking oil fumes, the rate of cell growth was not affected after exposure. We further examine the levels of gene expression with the RT-PCR methods. We found that the mRNA levels of cytochrome P4501A1 and 1B1 were increased to 2 to 4 fold of control 4hr after treatment with cooking oil fumes, and cytochrome P4502E1 was increased to 2 fold 24hr after treatment. Tumor growth factor .beta.1 was increased to 4 fold of control 24hr after treatment. The mRNA level of cytokines such as IL-2, IL-4, IL-6, IL-13, interferon-.gamma. and tumor necrosis factor-.alpha. were not induced after treatment with cooking oil fumes. In summary, treatment with cooking oil fumes didn't affect cell growth of lung adenocarcinoma CL3 cells. However, the gene expression levels of cytochrome P450s and tumor growth factor .beta.1 were increased after treatment with cooking oil fumes. |
