Signal Transduction Events and the Regulation of Cell Gr

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，通过临床前开发科学核心，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，和（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。(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。我们已经进行了信号通路对组蛋白乙酰化酶复合物调节细胞周期蛋白依赖性激酶抑制剂p21的启动子的影响的研究，p21是抗癌组蛋白去乙酰化酶抑制剂的重要转录靶点。我们正在对组蛋白去乙酰化酶抑制剂MS-275的I期试验进行转化科学和药效学研究，该试验正在NCI的实体瘤和约翰霍普金斯的Sidney Kimmel综合癌症中心和马里兰州Greenebaum癌症中心的血液恶性肿瘤中进行。我们在马里兰州大学的一项II期研究中研究了丁酸酯前药三丁酸甘油酯的药效学反应，我们正在与马约诊所和Karmanos癌症研究所的转化肿瘤学家合作，研究新HDAC抑制剂PXD 101的药效学方法。对于所有这些研究，我们已经建立了一个免疫细胞化学分析与图像分析的定量，并在过去的一年中，我们已经开发了一种新的多参数流式细胞术检测蛋白质乙酰化。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。临床前开发科学核心一直与内部研究人员合作进行一系列I期和II期临床试验。我是4项目前正在进行的临床试验的助理研究者。对于这些试验中的每一项，我们都与PI合作开发新的药效学终点，包括循环上皮肿瘤细胞的分析。今年，我们完成了对循环上皮肿瘤细胞的分析，用于perifosine在雄激素非依赖性前列腺癌中的壁内II期试验。(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。

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 Scientific 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. (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. We have performed studies of the impact of signaling pathways on histone acetylase complexes regulating the promoter of the cyclin-dependent kinase inhibitor p21, which is an important transcriptional target of the anticancer histone deacetylase inhibitors. We are performing the translational science and pharmacodynamic studies on the phase I trial of the histone deacetylase inhibitor MS-275, that is being run in solid tumors at the NCI and in hematologic malignancies at the Sidney Kimmel Comprehensive Cancer Center at Johns Hopkins and the University of Maryland Greenebaum Cancer Center. We have studied the pharmacodynamic response to the butyrate prodrug tributyrin in a phase II study at the University of Maryland, and we are working with translational oncologists at the Mayo Clinic and Karmanos Cancer Institute on pharmacodynamic approaches to the new HDAC inhibitor PXD101. For all of these studies we have set up an immunocytochemistry assay with image analysis for quantification, and in the past year we have developed a novel multiparameter flow cytometric assay for protein acetylation. 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. The Preclinical Development Scientific Core has been working with intramural investigators on a range of phase I and phase II clinical trials. I am an associate investigator on 4 currently active clinical trials. For each of these trials we work with the PI to develop novel pharmacodynamic endpoints, including analysis of circulating epithelial tumor cells. This year we completed analysis of circulating epithelial tumor cells for an intramural Phase II trial of perifosine in androgen-independent prostate cancer.(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.