Transcriptional Activation by Glucocorticoid Receptors

糖皮质激素受体的转录激活

• 批准号: 6535171
• 负责人: TREVOR K ARCHER
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/6535171
• 关键词: DNA binding protein; DNA footprinting; breast neoplasms; cell cycle proteins; chromatin; corticosteroid receptors; cyclin dependent kinase; environmental toxicology; gene induction /repression; genetic transcription; histones; hormone inhibitor; hormone regulation /control mechanism; hormone related neoplasm /cancer; human tissue; immunoprecipitation; osteosarcoma; phosphorylation; progesterone receptors; receptor expression; transcription factor

During FY2001 we built upon key observations that we made concerning the mechanisms by which steroid receptors activate transcription within breast cancer cells. We demonstrated that proteins involved in the manipulation of chromatin structure, chromatin remodeling machines, represent the key components in the cascade of events that results in the activation of the genetic program in human breast cancer cells. We have made significant advances in understanding the nature of the cellular response to prolonged glucocorticoid exposure. Our studies revealed that there is a profound reduction in the level of phosphorylated histone H1 that is directly linked to the cessation of transcription. The mechanism that underpins this result is the inhibition of the key cell cycle regulator CDK2 in response to glucocorticoid. In congruence with our hypothesis that understanding chromatin structure is vital to understanding gene regulation these events take place only in the context of chromatin. We continued to analyze the activity of the glucocorticoid receptor within breast and osteosarcoma cancer cells that differ in the expression of components of the chromatin remodeling machines. These cells display an altered response to a variety of clinically important hormone antagonist and will be useful in evaluating various anti-hormone strategies in breast cancer. In addition they are a unique resource to evaluate and characterize the impact of a number of environmental agents in human cells. To this end we have continued to develop methodologies that allow us to look at protein-DNA interactions within living cells, in vivo footprinting, as well as changes at the control regions of specific genes within living cell, chromatin immunoprecipitation (CHIP) assays.

在2001财政年度，我们建立了关于类固醇受体激活乳腺癌细胞内转录的机制的关键观察结果。我们证明了参与染色质结构操纵的蛋白质，染色质重塑机器，代表了导致人类乳腺癌细胞遗传程序激活的级联事件中的关键组成部分。我们在理解细胞对长期糖皮质激素暴露的反应的性质方面取得了重大进展。我们的研究表明，磷酸化组蛋白H1的水平显著降低，这与转录的停止直接相关。支持这一结果的机制是响应糖皮质激素的关键细胞周期调节因子CDK 2的抑制。与我们的假设一致，即理解染色质结构对于理解基因调控至关重要，这些事件仅发生在染色质的背景下。我们继续分析乳腺癌和骨肉瘤癌细胞中糖皮质激素受体的活性，这两种癌细胞在染色质重塑机器的成分表达上存在差异。这些细胞显示出对各种临床上重要的激素拮抗剂的反应改变，并将有助于评估乳腺癌中的各种抗激素策略。此外，它们是评估和表征许多环境因子对人类细胞影响的独特资源。为此，我们继续开发方法，使我们能够观察活细胞内的蛋白质-DNA相互作用，体内足迹，以及活细胞内特定基因控制区的变化，染色质免疫沉淀（CHIP）测定。