GLUCOCORTICOID INHIBITION OF PLASMINOGEN ACTIVATOR

糖皮质激素对纤溶酶原激活剂的抑制

• 批准号: 3179449
• 负责人: BRUCE A LITTLEFIELD
• 金额: $ 13.35万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-04-01 至 1989-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3179449
• 关键词: cell differentiation; cell growth regulation; clone cells; gene expression; genetic transcription; glucocorticoids; hormone regulation /control mechanism; human tissue; messenger RNA; molecular biology; plasminogen activator; radioimmunoassay; radiotracer; scintillation spectrometry; tissue /cell culture; urokinase

Plasminogen activators (PAs) are specialized proteases which are highly specific for the inactive zymogen plasminogen, which, upon cleavage by PAs, forms the active serine protease plasmin. PAs, which are expressed by both normal and malignant cell types, are frequently regulated by steroid and peptide hormones. It has been suggested that PA expression may be related to regulation of cell growth and/or differentiation state. We have demonstrated that LICR-LON-HMy2 human myeloma lymphoblast cells (HMy2 cells) secrete the PA urokinase (UK). These cells are growth inhibited by glucocorticoids, and their extracellular UK activity is virtually eliminated following exposure to glucocorticoids. This inhibition of UK is unrelated to glucocorticoid induction of inhibitors to either UK or activated plasmin. We propose to examine the mechanisms of glucocorticoid inhibition of HMy2 UK. We will establish 1) whether inhibition of extracellular UK involves decreased biosynthesis and/or secretion of UK; 2) whether decreases in steady-state levels of mRNA coding for UK are involved; 3) whether decreased transcription of the UK gene occurs; and 4) whether decreased UK gene transcription is a primary effect of glucocorticoids or whether it is mediated by glucocorticoid-induced transcriptional factors. The molecular biology approaches will be facilitated by the use of the human UK cDNA plasmid pHUK-8, which has been supplied to us by Dr. F. Blasi (currently at NIH). Appropriate contingency plans for all possible outcomes are discussed. The experiments outlined in this proposal will establish the validity of using glucocorticoid inhibition of HMy2 UK in future studies to examine mechanisms by which steroid-receptors turn off constitutive gene transcription. Such future studies would contrast with the many systems currently being used to examine steroid induction of specific genes. In summary, this work will provide the groundwork for a number of significant long-range goals: 1) examining the mechanisms of glucocorticoid inhibition of constitutive gene transcription; 2) studying potential relationships between glucocorticoid inhibition of UK, inhibition of cell growth, and development of steroid resistance in myeloma lymphoblasts; and 3) development of a potentially important clinical assay for prediction of glucocorticoid responsiveness in myeloma patients.

纤溶酶原激活物（PA）是高度依赖于细胞的特异性蛋白酶。 对无活性酶原纤溶酶原具有特异性，当被PA裂解时， 形成活性丝氨酸蛋白酶纤溶酶。 PA，由两个 正常和恶性细胞类型，经常受到类固醇的调节， 肽激素 PA的表达可能与 涉及细胞生长和/或分化状态的调节。 我们有 证明LICR-LON-HMy 2人骨髓瘤成淋巴细胞（HMy 2 细胞）分泌PA尿激酶（UK）。 这些细胞的生长受到 糖皮质激素，其细胞外UK活性几乎是 在接触糖皮质激素后消除。 英国的这种抑制是 与糖皮质激素诱导UK或 激活纤溶酶 我们建议研究糖皮质激素的作用机制 抑制HMy 2 UK。 我们将确定1）是否抑制 细胞外UK涉及UK的生物合成和/或分泌减少; 2） 尿激酶mRNA编码的稳态水平的降低是否 是否涉及; 3）是否发生UK基因的转录降低;以及4） 降低UK基因转录是否是 糖皮质激素或它是否介导的糖皮质激素诱导的 转录因子。 分子生物学方法将是 通过使用人UK cDNA质粒pHUK-8来促进， 由F博士提供。Blasi（目前在NIH）。 适当的应急 讨论了所有可能结果的计划。 中概述的实验 这一建议将确立使用糖皮质激素的有效性 在未来的研究中抑制HMy 2 UK，以检查 类固醇受体关闭组成型基因转录。 这种未来 研究将与目前使用的许多系统形成对比， 研究类固醇对特定基因的诱导作用。 总之，这项工作将 为一些重要的长期目标奠定基础：1） 探讨糖皮质激素抑制组成型基因的机制 转录; 2）研究糖皮质激素 抑制尿激酶、抑制细胞生长和产生类固醇 骨髓瘤淋巴母细胞的耐药性;和3）潜在的 预测糖皮质激素反应性重要临床试验 骨髓瘤患者。