Department of Genetic Ecotoxicology, Institute of Experimental Medicine AS CR, Prague, Czech Republic.
PLoS One. 2013 Jul 19;8(7):e69197. doi: 10.1371/journal.pone.0069197. Print 2013.
The cellular response to genotoxic treatment depends on the cell line used. Although tumor cell lines are widely used for genotoxicity tests, the interpretation of the results may be potentially hampered by changes in cellular processes caused by malignant transformation. In our study we used normal human embryonic lung fibroblasts (HEL12469 cells) and tested their response to treatment with benzo[a]pyrene (B[a]P) and extractable organic matter (EOM) from ambient air particles <2.5 µm (PM2.5) collected in two Czech cities differing in levels and sources of air pollution. We analyzed multiple endpoints associated with exposure to polycyclic aromatic hydrocarbons (PAHs) including the levels of bulky DNA adducts and the nucleotide excision repair (NER) response [expression of XPE, XPC and XPA genes on the level of mRNA and proteins, unscheduled DNA synthesis (UDS)]. EOMs were collected in the winter and summer of 2011 in two Czech cities with different levels and sources of air pollution. The effects of the studied compounds were analyzed in the presence (+S9) and absence (-S9) of the rat liver microsomal S9 fraction. The levels of bulky DNA adducts were highest after treatment with B[a]P, followed by winter EOMs; their induction by summer EOMs was weak. The induction of both mRNA and protein expression was observed, with the most pronounced effects after treatment with B[a]P (-S9); the response induced by EOMs from both cities and seasons was substantially weaker. The expression of DNA repair genes was not accompanied by the induction of UDS activity. In summary, our results indicate that the tested compounds induced low levels of DNA damage and affected the expression of NER genes; however, nucleotide excision repair was not induced.
细胞对遗传毒性处理的反应取决于所使用的细胞系。虽然肿瘤细胞系广泛用于遗传毒性测试，但由于恶性转化引起的细胞过程的变化，结果的解释可能会受到阻碍。在我们的研究中，我们使用了正常的人胚胎肺成纤维细胞（HEL12469 细胞），并测试了它们对苯并[a]芘（B[a]P）和从两个捷克城市收集的大气颗粒物<2.5 µm（PM2.5）中提取的可萃取有机物（EOM）的反应。我们分析了与多环芳烃（PAHs）暴露相关的多个终点，包括大体积 DNA 加合物的水平和核苷酸切除修复（NER）反应[信使 RNA 和蛋白质水平的 XPE、XPC 和 XPA 基因表达、非计划 DNA 合成（UDS）]。EOMs 于 2011 年冬季和夏季在两个捷克城市收集，这些城市的空气污染水平和来源不同。在存在（+S9）和不存在（-S9）大鼠肝微粒体 S9 部分的情况下分析了研究化合物的作用。大体积 DNA 加合物的水平在 B[a]P 处理后最高，其次是冬季 EOMs；夏季 EOMs 的诱导作用较弱。观察到 mRNA 和蛋白质表达的诱导，B[a]P（-S9）处理后效果最明显；两个城市和两个季节的 EOMs 诱导的反应明显较弱。DNA 修复基因的表达没有伴随着 UDS 活性的诱导。总之，我们的结果表明，测试的化合物诱导了低水平的 DNA 损伤，并影响了 NER 基因的表达；然而，核苷酸切除修复没有被诱导。
