Palma Selena, Cornetta Tommaso, Padua Luca, Cozzi Renata, Appolloni Massimo, Ievoli Elena, Testa Antonella
Section of Toxicology and Biomedical Sciences, ENEA Research Center, Casaccia, Via Anguillarese 301, 00060 Rome, Italy.
Mutat Res. 2007 Sep 1;633(1):1-12. doi: 10.1016/j.mrgentox.2007.03.014. Epub 2007 Jun 2.
Genotoxicity of tobacco smoke has long been investigated and tobacco smoke is considered to be one of the principal human carcinogens. Although its role in DNA-damage induction and cancer development has been documented, the mechanisms by which this happens are not well understood. Many chemical constituents of tobacco smoke are enzymatically metabolized by phase-I and phase-II enzymes, but modifications in coding and regulating sequences of these genes could influence their ability to detoxify these compounds. In this work, we studied several enzymes involved in the metabolism of xenobiotics, viz. the glutathione S-transferases (GST) M1, T1, P1 and A1, with respect to their influence on the genotoxic effects induced by cigarette smoking. We assessed the genotoxic effects of tobacco smoke on peripheral blood lymphocytes of 72 healthy caucasians by use of the chromosomal aberration (CA) assay and the micronucleus (MN) test. Genotypes of GST M1, T1, P1 and A1 were determined by means of the polymerase chain reaction and methods based on restriction fragment length polymorphism (RFLP). We found that smoke and gender are the two variables that most influence the DNA damage. In particular, we observed that female smokers seem to be more sensitive than male smokers, having a significantly higher frequency of CAs. Moreover, a significant increase in frequency of micronuclei in bi-nucleated cells (BNMN) was found in smokers, but not in non-smokers. This increase seems to be influenced not only by age and gender, but also by genetic constitution. Subjects carrying GSTM1-null genotype seemed to have an higher susceptibility to DNA damage induced by tobacco smoke than GSTM1-positive ones. When considering a combination of GST genotypes, we found a lower BNMN frequency in subjects with GSTP1 variant allele plus GSTM1-positive genotypes, while the most damaged cells are found in subjects bearing GSTM1-null plus GSTP1-wild type. Our results suggest that investigation of the association between several gene polymorphisms and important endpoints of DNA damage could contribute to better understanding the role of gene-gene interaction.
烟草烟雾的遗传毒性早已得到研究，烟草烟雾被认为是主要的人类致癌物之一。尽管其在诱导DNA损伤和癌症发展中的作用已有文献记载，但其发生机制尚未完全明确。烟草烟雾的许多化学成分可被I相和II相酶进行酶促代谢，但这些基因编码和调控序列的改变可能会影响它们对这些化合物的解毒能力。在本研究中，我们研究了几种参与异源物质代谢的酶，即谷胱甘肽S-转移酶（GST）M1、T1、P1和A1，探讨它们对吸烟诱导的遗传毒性效应的影响。我们通过染色体畸变（CA）试验和微核（MN）试验评估了烟草烟雾对72名健康白种人外周血淋巴细胞的遗传毒性效应。采用聚合酶链反应和基于限制性片段长度多态性（RFLP）的方法确定了GST M1、T1、P1和A1的基因型。我们发现，烟雾和性别是最影响DNA损伤的两个变量。具体而言，我们观察到女性吸烟者似乎比男性吸烟者更敏感，其染色体畸变频率显著更高。此外，吸烟者双核细胞（BNMN）中的微核频率显著增加，而非吸烟者则未出现这种情况。这种增加似乎不仅受年龄和性别的影响，还受遗传构成的影响。携带GSTM1无效基因型的受试者似乎比GSTM1阳性受试者对烟草烟雾诱导的DNA损伤更敏感。当考虑GST基因型的组合时，我们发现携带GSTP1变异等位基因加GSTM1阳性基因型的受试者的BNMN频率较低，而损伤最严重的细胞则出现在携带GSTM1无效加GSTP1野生型的受试者中。我们的结果表明，研究几种基因多态性与DNA损伤重要终点之间的关联可能有助于更好地理解基因-基因相互作用的作用。
