Signal Transduction Events and the Regulation of Cell Gr

信号转导事件与细胞Gr的调控

• 批准号: 7331717
• 负责人: JANE B TREPEL
• 金额: --
• 依托单位: DIVISION OF CLINICAL SCIENCES - NCI
• 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/7331717
• 关键词: Signal; Transduction; Events; Regulation; Cell

This project is designed to develop a new approach to cancer treatment through the study of growth, survival, and metastasis regulatory signal transduction events that identify molecular targets for anticancer drug development. Our work is divided into basic research and translational research through the Preclinical Development Research Core, a translational drug development facility that we have established. Our work is currently focused on (1) histone deacetylase as a target for anticancer drug development, and (2) the molecular mechanisms of hematopoietic cell regulation by beta-catenin and the identification of beta-catenin as a target in hematologic malignancies (3) development of novel pharmacodynamic assays, including assays for antiangiogenic therapy. (1) Our basic research on signal transduction pathways that can inhibit the growth of hormone-refractory prostate cancer cells led us to the identification of histone deacetylase as a critical target in this neoplasm. During this fiscal year we have finished development of a novel pharmacodynamic assay for assessment of HDAC inhibitor activity in vivo. The NCI has applied for a patent for our work, which is uniquely capable of analyzing HDAC inhibitor activity in as little blood as in a finger-stick, and can look at combination therapy pharmacodynamic responses by examining 7 parameters simultaneously. We have used this technology in 3 clinical trials, two of which have been written for publication. We have established a collaboration with Drs. Jay Bradner and Stuart Schreiber of the Broad Institute to use our technology to develop new HDAC inhibitors. (2) While studying the anticancer action of lovastatin, a drug that was brought to Phase I clinical trial at the NCI as a direct translation of our research, we found that a critical determinant of sensitivity to the proapoptotic activity of lovastatin was the integrity of beta-catenin protein. This led us to examine the role of beta-catenin in apoptosis. We used hematologic malignancies as our model and found that beta-catenin plays an unexpectedly vital role in these cells. Our data demonstrated that beta-catenin regulates leukemia cell survival, proliferation, and adhesive properties. These data identified beta-catenin as a novel target for anticancer drug development in hematologic malignancies. We are also studying the role of beta-catenin in mature peripheral lymphocytes, where we found that beta-catenin is critical in peripheral T-cell activation. Our data suggest that a burst of beta-catenin signaling is required for T-cell activation, and that failure to appropriately down-regulate beta-catenin signaling promotes transformation. Furthermore we delineated the pathway for posttranslational regulation of beta-catenin in human PBL. These data demonstrate that beta-catenin is controlled by the beta-TrCP1-associated ubiquitin ligase complex and that stabilization of beta-catenin with TCR ligation is achieved by calcium flux, calcineurin activation, and beta-catenin serine/threonine dephosphorylation, which blocks targeting of beta-catenin to the proteasome. This leads to accumulation of cytoplasmic and nuclear beta-catenin and activation of beta-catenin target genes. Furthermore we found that IL-2 is a beta-catenin-responsive gene and have begun mapping the responsive sites on the IL-2 promoter.We had published previously that beta-catenin promotes proliferation of the adult T-cell leukemia (ATL) cell line HUT102. We have now investigated the mechanism of beta-catenin signaling in ATL and discovered that beta-catenin is induced by HTLV-1 Tax and cooperates with Tax in transcriptional activation. In the ATL cell line HUT102 and Jurkat T-ALL cells, Tax expression increased activity of a luciferase reporter driven by the beta-catenin promoter. Real-time RT-PCR confirmed that Tax increased beta-catenin expression.

该项目旨在通过研究生长，存活和转移调节信号转导事件，确定抗癌药物开发的分子靶点，开发一种新的癌症治疗方法。我们的工作分为基础研究和转化研究，通过临床前开发研究核心，我们已经建立了一个转化药物开发设施。我们的工作目前集中在（1）组蛋白去乙酰化酶作为抗癌药物开发的靶点，（2）β-连环蛋白调节造血细胞的分子机制和β-连环蛋白作为血液恶性肿瘤靶点的鉴定（3）开发新的药效学测定，包括抗血管生成治疗的测定。(1)我们的信号转导途径，可以抑制肿瘤难治性前列腺癌细胞的生长的基础研究，使我们确定组蛋白脱乙酰酶作为一个关键的目标，在这种肿瘤。在本财政年度，我们完成了一种用于评估HDAC抑制剂体内活性的新型药效学试验的开发。NCI已经为我们的工作申请了专利，该工作独特地能够在像手指针刺一样少的血液中分析HDAC抑制剂活性，并且可以通过同时检查7个参数来观察联合治疗的药效学反应。我们已经在3项临床试验中使用了这项技术，其中两项已经撰写出版。我们与布罗德研究所的Jay布拉德纳和Stuart Schreiber博士建立了合作关系，利用我们的技术开发新的HDAC抑制剂。(2)在研究洛伐他汀（一种在NCI进行I期临床试验的药物，作为我们研究的直接翻译）的抗癌作用时，我们发现对洛伐他汀促凋亡活性敏感性的关键决定因素是β-连环蛋白的完整性。这使我们研究β-连环蛋白在细胞凋亡中的作用。我们使用血液恶性肿瘤作为我们的模型，发现β-连环蛋白在这些细胞中起着意想不到的重要作用。我们的数据表明，β-连环蛋白调节白血病细胞的存活，增殖和粘附特性。这些数据确定β-连环蛋白作为血液恶性肿瘤抗癌药物开发的新靶点。我们也在研究β-连环蛋白在成熟外周淋巴细胞中的作用，我们发现β-连环蛋白在外周T细胞活化中至关重要。我们的数据表明，β-连环蛋白信号的爆发是T细胞活化所必需的，并且未能适当下调β-连环蛋白信号促进转化。此外，我们描绘了人PBL中β-连环蛋白的翻译后调节途径。这些数据表明，β-连环蛋白由β-TrCP 1相关的泛素连接酶复合物控制，并且通过TCR连接实现β-连环蛋白的稳定化是通过钙通量、钙调磷酸酶激活和β-连环蛋白丝氨酸/苏氨酸去磷酸化来实现的，这阻断了β-连环蛋白靶向蛋白酶体。这导致细胞质和细胞核β-连环蛋白的积累和β-连环蛋白靶基因的激活。此外，我们发现IL-2是一个β-catenin应答基因，并已开始定位IL-2启动子上的应答位点，我们以前曾发表过β-catenin促进成人T细胞白血病（ATL）细胞系HUT 102的增殖。我们现在已经研究了ATL中β-catenin信号转导的机制，发现β-catenin是由HTLV-1 Tax诱导的，并与Tax协同转录激活。在ATL细胞系HUT 102和Jurkat T-ALL细胞中，Tax表达增加了由β-连环蛋白启动子驱动的荧光素酶报告基因的活性。Real-time RT-PCR证实Tax增加了β-catenin的表达。