Genetic toxicology data have traditionally been utilized for hazard identification to provide a binary call for a compound's risk. Recent advances in the scientific field, especially with the development of high-throughput methods to quantify DNA damage, have influenced a change of approach in genotoxicity assessment. The in vitro MultiFlow® DNA Damage Assay is one such method which multiplexes γH2AX, p53, phospho-histone H3 biomarkers into a single-flow cytometric analysis (Bryce et al., [2016]: Environ Mol Mutagen 57:546-558). This assay was used to study human TK6 cells exposed to each of eight topoisomerase II poisons for 4 and 24 hr. Using PROAST v65.5, the Benchmark Dose approach was applied to the resulting flow cytometric datasets. With "compound" serving as covariate, all eight compounds were combined into a single analysis, per time point and endpoint. The resulting 90% confidence intervals, plotted in Log scale, were considered as the potency rank for the eight compounds. The in vitro MultiFlow data showed a maximum confidence interval span of 1Log, which indicates data of good quality. Patterns observed in the compound potency rank were scrutinized by using the expert rule-based software program Derek Nexus, developed by Lhasa Limited. Compound sub-classification and structural alerts were considered contributory to the potencies observed for the topoisomerase II poisons studied herein. The Topo II poison Adverse Outcome Pathway was evaluated with MultiFlow endpoints serving as Key Events. The step-wise approach described herein can be considered as a foundation for risk assessment of compounds within a specific mode of action of interest. Environ. Mol. Mutagen. 2020. © 2020 Wiley Periodicals, Inc.

中文翻译：

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DNA损伤生物标志物响应的基准剂量分析可为化合物的拓扑异构酶II抑制剂类提供化合物效价和不良结果途径信息。

传统上，遗传毒理学数据已用于危险识别，以提供对化合物风险的二元调用。科学领域的最新进展，特别是随着高通量方法定量DNA损伤的发展，已经影响了遗传毒性评估方法的变化。体外DNA损伤检测是一种将γH2AX，p53，磷酸组蛋白H3生物标记物多路复用到单流式细胞仪分析中的方法（Bryce等人，[2016]：Environ Mol Mutagen 57：546-558）。该测定法用于研究暴露于八种拓扑异构酶II毒物中的每一种的人TK6细胞4和24小时。使用PROAST v65.5，将基准剂量方法应用于所得的流式细胞数据集。以“化合物”作为协变量，将所有八个化合物合并为一个分析，每个时间点和终点。以对数标度绘制的所得90％置信区间被认为是这8种化合物的效价等级。体外MultiFlow数据显示最大置信区间为1Log，表明数据质量良好。使用由拉萨有限公司开发的基于规则的专家软件程序，仔细检查在化合物效价等级中观察到的模式。化合物亚分类和结构警报被认为有助于本文研究的拓扑异构酶II毒物的效力。使用MultiFlow端点作为关键事件评估了Topo II毒药不良结果途径。本文所述的逐步方法可以被认为是在特定目标作用模式内对化合物进行风险评估的基础。环境。大声笑 诱变剂。