National Center for Computational Toxicology, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina, USA.
Chem Res Toxicol. 2010 Mar 15;23(3):578-90. doi: 10.1021/tx900325g.
Exposure to environmental chemicals adds to the burden of disease in humans and wildlife to a degree that is difficult to estimate and, thus, mitigate. The ability to assess the impact of existing chemicals for which little to no toxicity data are available or to foresee such effects during early stages of chemical development and use, and before potential exposure occurs, is a pressing need. However, the capacity of the current toxicity evaluation approaches to meet this demand is limited by low throughput and high costs. In the context of EPA's ToxCast project, we have evaluated a novel cellular biosensor system (Factorial (1) ) that enables rapid, high-content assessment of a compound's impact on gene regulatory networks. The Factorial biosensors combined libraries of cis- and trans-regulated transcription factor reporter constructs with a highly homogeneous method of detection enabling simultaneous evaluation of multiplexed transcription factor activities. Here, we demonstrate the application of the technology toward determining bioactivity profiles by quantitatively evaluating the effects of 309 environmental chemicals on 25 nuclear receptors and 48 transcription factor response elements. We demonstrate coherent transcription factor activity across nuclear receptors and their response elements and that Nrf2 activity, a marker of oxidative stress, is highly correlated to the overall promiscuity of a chemical. Additionally, as part of the ToxCast program, we identify molecular targets that associate with in vivo end points and represent modes of action that can serve as potential toxicity pathway biomarkers and inputs for predictive modeling of in vivo toxicity.
接触环境化学物质会给人类和野生动物的疾病负担增加到难以估计的程度，因此难以减轻。评估现有化学物质的影响的能力，这些化学物质几乎没有毒性数据，或者在化学物质开发和使用的早期阶段预见这些影响，在潜在暴露发生之前，是一个紧迫的需求。然而，当前毒性评估方法的能力受到低通量和高成本的限制。在 EPA 的 ToxCast 项目的背景下，我们评估了一种新的细胞生物传感器系统（因子设计 (1) ），该系统能够快速、高内涵地评估化合物对基因调控网络的影响。因子生物传感器将顺式和反式调节转录因子报告构建体的文库与高度同质的检测方法相结合，能够同时评估多路转录因子活性。在这里，我们通过定量评估 309 种环境化学物质对 25 种核受体和 48 种转录因子反应元件的影响，展示了该技术在确定生物活性谱方面的应用。我们证明了核受体及其反应元件之间的转录因子活性具有一致性，并且 Nrf2 活性（氧化应激的标志物）与化学物质的整体混杂性高度相关。此外，作为 ToxCast 计划的一部分，我们确定了与体内终点相关的分子靶标，并代表了可能作为毒性途径生物标志物的作用模式，并可作为体内毒性预测模型的输入。
