Targeting Smad3-Ski for Therapeutic Development in Pancreatic Cancer

以 Smad3-Ski 为靶点进行胰腺癌治疗开发

基本信息

批准号：
7506720
负责人：
F. Michael Hoffmann
金额：
$ 16.71万
依托单位：
UNIVERSITY OF WISCONSIN-MADISON
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-06-01 至 2010-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7506720
关键词：
Address Affinity Binding Binding Proteins Binding Sites Biochemical Biological Assay CDKN1A gene Cancer Patient Cell Line Cell Proliferation Cell Survival Cells Cervix carcinoma Chemicals Complex Defect Development Disease Disruption Epithelial Cells Esophageal Squamous Cell Carcinoma FAST2 protein Foundations Funding Gene Expression Grant Growth Hot Spot Human Laboratories Lead Ligands Malignant Neoplasms Malignant neoplasm of pancreas Mediating Molecular Bank Mutation North Carolina Operative Surgical Procedures Pancreas Pathway interactions Peptide aptamers Peptides Pharmaceutical Preparations Phenotype Phosphorylation Pilot Projects Protein Binding Protein Overexpression Proteins Public Health Reagent Reporter Genes Reporting Scaffolding Protein Screening procedure Signal Transduction Signal Transduction Pathway Skiing Smad Proteins Smad protein Small Interfering RNA Specificity Specimen Survival Rate Testing Therapeutic Transforming Growth Factor beta Universities Xenograft Model aptamer assay development base cancer cell drug development epithelial to mesenchymal transition high throughput screening human TGFB1 protein improved inhibitor/antagonist melanoma novel novel therapeutics oncoprotein p21 preclinical study prevent protein protein interaction receptor response size small molecule small molecule libraries therapeutic target transcription factor

项目摘要

DESCRIPTION (provided by applicant): Defects in the transforming growth factor beta (TGF-beta) signal transduction pathway are well-known in pancreatic cancer; the most well-established alteration is mutation of the Smad4, originally known as deleted in pancreatic cancer 4 (Dpc-4), which occurs in approximately 50% of human pancreatic cancers examined. TGF-beta binding to its transmembrane receptors leads to phosphorylation of Smad2 and Smad3, which form heterotrimeric complexes with Smad4 to inhibit growth of normal pancreatic epithelial cells. In pancreatic cancer cells, TGF-beta-induced growth inhibition is prevented either by loss of Smad4 or by inhibiting Smad-dependent growth arrest. Heider and colleagues recently reported that Smad- dependent growth arrest in pancreatic cancer cells is inhibited by overexpression of the protein Ski, a protein known to bind directly to Smads to inhibit signaling. Nine of 11 human pancreatic cancer specimens examined overexpressed Ski, which was not expressed in 9 normal pancreatic specimens. siRNA knockdown of Ski in Panc-1 cells restored TGF-beta-induced p21 expression and growth inhibition in culture and in a xenograft model (Heider et al., Annals of Surgery 246: 61-68, 2007). Over-expression of Ski also has been implicated in the cancer phenotype of esophageal squamous cell carcinoma, melanoma and cervical carcinoma. We propose a pilot project to test the hypothesis that pharmacological disruption of the Ski-Smad interaction will restore TGF-beta signaling in Ski-overexpressing pancreatic cancer cells. We hope that these studies might lead to a novel therapeutic approach for treating some pancreatic cancers. We have identified small constrained peptides, called peptide aptamers, and one small molecule ligand that inhibits Smad3-Ski binding. In Specific Aim 1, we propose to optimize our initial aptamer reagents for disrupting Smad-Ski interactions in pancreatic cancer cells over-expressing Ski and to define the Ski protein binding "hot spots" on Smads. In Specific Aim 2, we propose to target the Ski-binding hot spots for discovery of additional small molecules ligands through screening of available chemical libraries. In Specific Aim 3, our initial active compound and additional drug-like chemicals from the Aim 2 screens will be optimized for their potency and selectivity in restoring TGF-beta growth inhibition in Ski-overexpressing human pancreatic cancer cells. PUBLIC HEALTH RELEVANCE: Most pancreatic cancer patients treated with current therapies survive for only 3 to 6 months; the overall 5- year survival rate for this disease is <5%. We propose pre-clinical studies to evaluate a new therapeutic target in pancreatic cancer cells, the Ski-Smad protein interaction. We will use peptide aptamers and drug- like chemicals to disrupt Ski-Smad, restore an important growth inhibitory pathway in the pancreatic cancer cells, and provide proof-of-principle that Ski-Smad is a valid, druggable target for new drug development to aid pancreatic cancer patients.

描述（由申请人提供）：转化生长因子β（TGF-β）信号转导途径的缺陷在胰腺癌中是众所周知的；最明确的改变是 Smad4 的突变，最初被称为胰腺癌 4 缺失 (Dpc-4)，大约 50% 的人类胰腺癌中都会出现这种突变。 TGF-β与其跨膜受体结合导致 Smad2 和 Smad3 磷酸化，后者与 Smad4 形成异源三聚体复合物，抑制正常胰腺上皮细胞的生长。在胰腺癌细胞中，Smad4 缺失或抑制 Smad 依赖性生长停滞可阻止 TGF-β 诱导的生长抑制。 Heider 及其同事最近报道，胰腺癌细胞中 Smad 依赖性生长停滞受到 Ski 蛋白过度表达的抑制，Ski 蛋白是一种已知直接与 Smad 结合以抑制信号传导的蛋白。检查的 11 份人类胰腺癌标本中，有 9 份 Ski 过度表达，而 9 份正常胰腺标本中不表达 Ski。 Panc-1细胞中Ski的siRNA敲低恢复了培养物和异种移植模型中TGF-β诱导的p21表达和生长抑制(Heider等人，Annals ofurgery 246：61-68，2007)。 Ski 的过度表达还与食管鳞状细胞癌、黑色素瘤和宫颈癌的癌症表型有关。我们提出了一个试点项目来测试这样的假设：药理学破坏 Ski-Smad 相互作用将恢复 Ski 过度表达的胰腺癌细胞中的 TGF-β 信号传导。我们希望这些研究可能会带来一种治疗某些胰腺癌的新方法。我们已经鉴定了称为肽适体的小受限肽，以及一种抑制 Smad3-Ski 结合的小分子配体。在具体目标 1 中，我们建议优化我们的初始适体试剂，以破坏过度表达 Ski 的胰腺癌细胞中的 Smad-Ski 相互作用，并定义 Smad 上的 Ski 蛋白结合“热点”。在具体目标 2 中，我们建议通过筛选可用的化学文库，瞄准 Ski 结合热点，发现其他小分子配体。在Specific Aim 3中，我们的初始活性化合物和来自Aim 2筛选的其他药物样化学物质将针对其在Ski过度表达的人胰腺癌细胞中恢复TGF-β生长抑制的效力和选择性进行优化。公共卫生相关性：大多数接受当前疗法治疗的胰腺癌患者只能存活 3 至 6 个月；这种疾病的总体 5 年生存率<5%。我们提出临床前研究来评估胰腺癌细胞的新治疗靶点，即 Ski-Smad 蛋白相互作用。我们将使用肽适体和类药物化学物质来破坏 Ski-Smad，恢复胰腺癌细胞中重要的生长抑制途径，并提供原理证明，证明 Ski-Smad 是新药开发的有效、可成药靶点帮助胰腺癌患者。