Lechevrel M, Casson A G, Wolf C R, Hardie L J, Flinterman M B, Montesano R, Wild C P
Unit of Environmental Carcinogenesis, International Agency for Research on Cancer, Lyon, France.
Carcinogenesis. 1999 Feb;20(2):243-8. doi: 10.1093/carcin/20.2.243.
The expression of cytochrome (CYP) P450 enzymes in human oesophageal mucosa was investigated in a total of 25 histologically non-neoplastic surgical tissue specimens by using specific antibodies in immunoblots and by RT-PCR mRNA analysis. The presence of CYP1A, 2E1, 3A and 4A enzymes was demonstrated by both techniques; CYP2A reactive protein was also detected by immunoblot. The presence of CYP4B1 mRNA was established but no specific antibody was available for detection of the corresponding protein by immunoblot. CYP2B6/7 mRNA was not detected in any sample. The mRNA transcripts for CYP1A1, 2E1, 4A11 and 4B1 were consistently detected in the majority of samples (>84%), whereas CYP1A2 mRNA was only detected in 11 of 19 specimens examined. An RT-PCR method to differentiate CYP3A4 and 3A5 mRNA was developed. This demonstrated CYP3A5 mRNA expression in all samples tested, whereas CYP3A4 mRNA was not detectable, suggesting that CYP3A5 is the major CYP3A protein in human oesophagus. There were significant interindividual variations in the amount of proteins, ranging from 8-fold for CYP4A to 43-fold for CYP2E1. For each patient, data on exposure to risk factors for oesophageal cancer were available, including tobacco smoke, alcohol, gastro-oesophageal reflux and hot beverage consumption. None of these risk factors or other patient characteristics (age, sex, tumour location and tumour stage) were correlated with the protein level of the individual CYP enzymes as determined by quantitation of immunoblot staining. However, the small series of samples precludes any strong conclusion concerning the lack of such correlations. There were no differences between squamous cell carcinomas and adenocarcinomas in either the qualitative or quantitative expression of the CYP enzymes. These data demonstrate that a range of CYP enzymes are expressed in human oesophageal mucosa and indicate that this tissue has the capacity to activate chemical carcinogens to reactive DNA binding metabolites.
通过免疫印迹法使用特异性抗体以及逆转录聚合酶链反应（RT-PCR）mRNA分析，对总共25份组织学上无肿瘤的手术组织标本中的细胞色素（CYP）P450酶在人食管黏膜中的表达进行了研究。两种技术均证实了CYP1A、2E1、3A和4A酶的存在；免疫印迹法也检测到了CYP2A反应性蛋白。确定了CYP4B1 mRNA的存在，但没有特异性抗体可通过免疫印迹法检测相应蛋白。在任何样本中均未检测到CYP2B6/7 mRNA。在大多数样本（>84%）中始终检测到CYP1A1、2E1、4A11和4B1的mRNA转录本，而在19份检测标本中仅在11份中检测到CYP1A2 mRNA。开发了一种区分CYP3A4和3A5 mRNA的RT-PCR方法。这表明在所有测试样本中均有CYP3A5 mRNA表达，而未检测到CYP3A4 mRNA，提示CYP3A5是人类食管中主要的CYP3A蛋白。蛋白质含量存在显著的个体间差异，CYP4A为8倍，CYP2E1为43倍。对于每位患者，均有关于食管癌危险因素暴露的数据，包括吸烟、饮酒、胃食管反流和热饮摄入。通过免疫印迹染色定量测定，这些危险因素或其他患者特征（年龄、性别、肿瘤位置和肿瘤分期）均与个体CYP酶的蛋白水平无关。然而，样本数量较少，无法就缺乏这种相关性得出任何有力结论。在CYP酶的定性或定量表达方面，鳞状细胞癌和腺癌之间没有差异。这些数据表明一系列CYP酶在人食管黏膜中表达，并表明该组织有能力将化学致癌物激活为具有反应性的DNA结合代谢物。
