Seidel Shawn D, Kan H Lynn, Stott William T, Schisler Melissa R, Gollapudi B Bhaskar
Toxicology & Environmental Research and Consulting, The Dow Chemical Company, Midland, Michigan 48674, USA.
Environ Mol Mutagen. 2003;42(1):19-25. doi: 10.1002/em.10169.
It is believed that some aspects of genotoxicity are associated with changes in the transcription levels of certain genes, especially those involved in DNA repair and cell cycle control. Additionally, it is hypothesized that chemicals sharing a common mode of genotoxicity should exhibit similar changes in gene expression. We have evaluated these hypotheses by analyzing transcriptome profiles of mouse lymphoma L5178Y/TK(+/-) cells treated with bleomycin and hydrogen peroxide, two mutagens that produce genotoxicity by generating reactive free radicals. The cells were treated for 4 hr and RNA was isolated at the end of the treatment and after a 20 hr recovery. Transcriptome analyses were performed using the Clontech Mouse 1.2K cDNA microarray (1,185 genes) and hybridization with a (32)[P]-labeled probe. Of the genes examined, each mutagen altered the expression (1.5-fold or greater) of only two genes after the 4 hr treatment. In cells allowed to recover for 20 hr after treatment, bleomycin and hydrogen peroxide altered the expression of 8 and 5 genes, respectively. Many of the altered genes have some association with apoptosis. Of these genes, three (the genes encoding granzyme A, integrin beta 7, and 45 kDa calcium-binding protein precursor) were in common between chemical treatments. The expression of DNA repair and cell cycle controlling genes present on the array was not affected by the treatments. These results show that bleomycin and hydrogen peroxide both have unique and commonly regulated genes that have the potential to serve as biomarkers of exposure to agents causing DNA damage by free radical mechanisms.
人们认为，遗传毒性的某些方面与特定基因转录水平的变化有关，尤其是那些参与DNA修复和细胞周期调控的基因。此外，据推测，具有共同遗传毒性模式的化学物质在基因表达上应表现出相似的变化。我们通过分析用博来霉素和过氧化氢处理的小鼠淋巴瘤L5178Y/TK(+/-)细胞的转录组图谱，对这些假设进行了评估，这两种诱变剂通过产生活性自由基产生遗传毒性。细胞处理4小时，处理结束时以及恢复20小时后分离RNA。使用Clontech小鼠1.2K cDNA微阵列（1185个基因）进行转录组分析，并与(32)[P]标记的探针杂交。在检测的基因中，每种诱变剂在4小时处理后仅改变了两个基因的表达（1.5倍或更高）。在处理后允许恢复20小时的细胞中，博来霉素和过氧化氢分别改变了8个和5个基因的表达。许多改变的基因与细胞凋亡有一定关联。在这些基因中，化学处理之间有三个基因（编码颗粒酶A、整合素β7和45 kDa钙结合蛋白前体的基因）是共同的。阵列上存在的DNA修复和细胞周期调控基因的表达不受处理影响。这些结果表明，博来霉素和过氧化氢都有独特且共同调控的基因，这些基因有可能作为暴露于通过自由基机制导致DNA损伤的试剂的生物标志物。
