Abernethy Diane J, Kleymenova Elena V, Rose Jason, Recio Leslie, Faiola Brenda
CIIT Centers for Health Research, Research Triangle Park, North Carolina 27709, USA.
Toxicol Sci. 2004 May;79(1):82-9. doi: 10.1093/toxsci/kfh095. Epub 2004 Feb 19.
Chronic human exposure to benzene has been linked to several hematopoietic disorders, including leukemia and lymphomas. Certain benzene metabolites, including benzoquinone (BQ), are genotoxic and mutagenic. Bone marrow stem cells are targets for benzene-induced cytotoxicity and DNA damage that could result in changes to the genome of these progenitor cells, thereby leading to hematopoietic disorders and cancers. Human bone marrow CD34(+) hematopoietic progenitor cells (HPC) were exposed in vitro to 1,4-BQ to assess cytotoxicity, genotoxicity, and DNA damage responses and the molecular mechanisms associated with these events. CD34(+) HPC from 10 men and 10 women were exposed to 0, 1, 5, 10, 15, or 20 microM of 1,4-BQ and analyzed 72 h later. Apoptosis and cytotoxicity were dose-dependent, with exposure to 10 microM 1,4-BQ resulting in approximately 60% cytotoxicity relative to untreated controls. A significant increase in the percentage of micronucleated CD34(+) cells was detected in cultures treated with 1,4-BQ. In addition, the p21 mRNA level was elevated in 1,4-BQ-treated cells, suggesting that human CD34(+) cells utilize the p53 pathway in response to 1,4-BQ-induced DNA damage. However, there were no significant changes in mRNA levels of the DNA repair genes ku80, rad51, xpa, xpc, and ape1 as well as p53 following treatment with 1,4-BQ. Although interindividual variations were evident in the cellular response to 1,4-BQ, there was no gender difference in the response overall. These results show that human CD34(+) cells are sensitive targets for 1,4-BQ toxicity that use the p53 DNA damage response pathway in response to genotoxic stress. Human CD34(+) HPC will be useful for testing the toxicity of other benzene metabolites and various hematotoxic chemicals.
长期接触苯与多种造血系统疾病有关，包括白血病和淋巴瘤。某些苯代谢产物，如苯醌（BQ），具有遗传毒性和致突变性。骨髓干细胞是苯诱导的细胞毒性和DNA损伤的靶标，这可能导致这些祖细胞基因组发生变化，从而引发造血系统疾病和癌症。体外将人骨髓CD34(+)造血祖细胞（HPC）暴露于1,4 - BQ中，以评估细胞毒性、遗传毒性、DNA损伤反应以及与这些事件相关的分子机制。来自10名男性和10名女性的CD34(+) HPC暴露于0、1、5、10、15或20微摩尔的1,4 - BQ中，并在72小时后进行分析。凋亡和细胞毒性呈剂量依赖性，相对于未处理的对照，暴露于10微摩尔1,4 - BQ导致约60%的细胞毒性。在用1,4 - BQ处理的培养物中检测到微核化CD34(+)细胞的百分比显著增加。此外，在1,4 - BQ处理的细胞中p21 mRNA水平升高，表明人CD34(+)细胞利用p53途径来应对1,4 - BQ诱导的DNA损伤。然而，在用1,4 - BQ处理后，DNA修复基因ku80、rad51、xpa、xpc和ape1以及p53的mRNA水平没有显著变化。尽管个体对1,4 - BQ的细胞反应存在明显差异，但总体反应没有性别差异。这些结果表明，人CD34(+)细胞是1,4 - BQ毒性的敏感靶标，在遗传毒性应激下利用p53 DNA损伤反应途径。人CD34(+) HPC将有助于测试其他苯代谢产物和各种血液毒性化学物质的毒性。
