Khoury Laure, Zalko Daniel, Audebert Marc
Toxalim, Université de Toulouse, INRAE, INP-ENVT, INP-EI-Purpan, Université de Toulouse 3 Paul Sabatier, Toulouse, France.
Toxalim, Université de Toulouse, INRAE, INP-ENVT, INP-EI-Purpan, Université de Toulouse 3 Paul Sabatier, Toulouse, France.
Mutat Res Genet Toxicol Environ Mutagen. 2020 Apr;852:503165. doi: 10.1016/j.mrgentox.2020.503165. Epub 2020 Mar 5.
Human risk assessment of genotoxic chemicals is an important area of research. However, the specificity of in vitro mammalian genotoxicity assays is sometime low, as they yield to misleading positive results that are not observe in in vivo studies. Apoptosis can be a confounding factor in the interpretation of the results. Recently, a new strategy for genotoxicity screening, based on the combined analysis of phosphorylated histones H2AX (γH2AX) and H3 (pH3), was proposed to discriminate efficiently aneugenic from clastogenic compounds. However, γH2AX biomarker could also be induce by apoptosis. The aim of the present study was to investigate the specificity of this genotoxic biomarker. For this purpose, we analyzed 26 compounds inducing apoptosis by different mechanism of action, with the γH2AX assay in three human cell lines after 24 h treatment. Most of the tested chemicals were negative in the assay, whatever the cell line tested. The few compounds that generated positive data have also been report positive in other genotoxicity assays. The data presented here demonstrate that the γH2AX assay is not vulnerable to the generation of misleading positive results by apoptosis inducers. Currently, no formal guidelines have been approve for the γH2AX assay for regular genotoxicity studies, but we suggest that this biomarker could be used as a new standard genotoxicity assay.
对具有基因毒性的化学物质进行人体风险评估是一个重要的研究领域。然而，体外哺乳动物基因毒性检测的特异性有时较低，因为它们会产生在体内研究中未观察到的误导性阳性结果。细胞凋亡可能是结果解读中的一个混杂因素。最近，有人提出了一种基于磷酸化组蛋白H2AX（γH2AX）和H3（pH3）联合分析的基因毒性筛查新策略，以有效区分非整倍体诱导剂和染色体断裂剂。然而，γH2AX生物标志物也可能由细胞凋亡诱导产生。本研究的目的是调查这种基因毒性生物标志物的特异性。为此，我们在处理24小时后，在三种人类细胞系中用γH2AX检测法分析了26种通过不同作用机制诱导细胞凋亡的化合物。无论检测哪种细胞系，大多数受试化学物质在该检测中均为阴性。少数产生阳性数据的化合物在其他基因毒性检测中也被报告为阳性。此处呈现的数据表明，γH2AX检测法不易受到凋亡诱导剂产生的误导性阳性结果的影响。目前，尚未批准将γH2AX检测法用于常规基因毒性研究的正式指南，但我们建议这种生物标志物可作为一种新的标准基因毒性检测方法。
