DIOXIN-EPITHELIAL CELL INTERACTIONS: MECHANISM & ASSAY

虽然涉及动物和分子技术的大量调查 生物学已经定义了一些与二恶英中毒有关的参数， 这种毒性的机制和靶器官尚不清楚。当前 政府致力减轻二恶英可能对公众健康造成的影响 曝光包括通过昂贵的高分辨率检测这些化合物 化学分析。然而，这种技术，虽然精确和 决定性的，都很昂贵，可能无法处理大量的 样本需要在环境监测计划中进行测试。 我们最近证明了2，3，7，8-TCDD在 体外诱导融合后细胞增殖的可逆性变化 来自角化的细胞系的形态，命名为XBF 从小鼠畸胎瘤中克隆的细胞系(XB)。浓缩物 低至10~(-11)M的2，3，7，8-TCDD会引起“扁平细胞效应”。 初步实验表明，平板电池效应将是有用的。 作为研究与之相关的毒性机制的新工具 接触二恶英类化合物。在本实验室完成的其他工作 表明这种影响仅限于毒性较高的多氯联苯 二恶英和二苯并呋喃，该系统有潜力用作 检测这一活性的相对简单和廉价的方法 在各种环境样本中，包括空气、土壤、沉积物、鱼、烟尘、 表面，还有水。 我们建议通过研究来探讨类二恶英的活性机制。 使用最有效的2，3，7，8-TCDD的扁平细胞效应的各个方面 这一群体的成员，作为原型。这些研究将集中在 XBF系的特异性、饲养细胞和细胞-细胞的功能 相互作用，这种效应与分化的关系，以及 这种效应可能与ah基因座的基因产物有关。我们 还建议确定使用诱导法的可行性 扁平细胞效应作为二恶英类化合物的半定量筛选方法 环境样品中化合物的验证研究，使用纯 化合物、实际样品、样品结构以及 确定化学相互作用程度的化学物质。这样的化验 将允许对阳性样本进行优先排序，以获得后续的高 消解化学分析和消除样品中的阴性样品 进一步测试。这将允许更合理地使用更精确的 但分析技术有限。

While numerous investigations involving animals and techniques of molecular biology have defined some parameters relating to dioxin intoxication, the mechanism of this toxicity and the target organ remain unknown. Current efforts to alleviate the possible public health consequence of dioxin exposure involve detection of these compounds by costly high resolution chemical analysis. However, such techniques, while both precise and definitive, are expensive and may not be able to handle the vast number of samples needed to be tested in an environmental monitoring program. We have recently demonstrated that 2,3,7,8-TCDD is extremely potent in inducing a reversible in vitro change in post confluent cell proliferation and morphology of a cell line, designated XBF, derived frm a keratinizing cell line (XB) cloned from a mouse teratoma. Concentrations of 2,3,7,8-TCDD as low as 10-11 M will induce the "flat-cell effect". Preliminary experiments indicate that the flat-cell effect will be useful as a novel tool for the study of the mechanism of toxicity associated with exposure to dioxinlike compounds. Other work performed in this laboratory indicates that this effect is specific for the more toxic polychlorinated dioxins and dibenzofurans, and that this system has potential for use as a relatively simple and inexpensive assay for the detection of this activity in various environmental samples including air, soil, sediment, fish, soot, surfaces, and water. We propose to investigate the mechanism of dioxinlike activity by studying various aspects of the flat-cell effect using 2,3,7,8-TCDD, the most potent member of this group, as a prototype. These studies will focus on the specificity of the XBF line, the function of the feeder cells and cell-cell interactions, the relation of this effect to differentiation and the possible association of this effect with gene products of the Ah locus. We also propose to determine the feasibility of using the induction of the flat-cell effect as a semiquantitative screening assay for dioxinlike compounds in environmental samples by validation studies using pure compounds, actual samples, and sample constructs as well as mixtures of chemicals to determine the extent of chemical interactions. Such an assay would allow priority ranking of positive samples for subsequent high resolution chemical analysis and the elimination of negative samples from further testing. This would allow more rational use of the more precise but limited analytical techniques.