Targeting Smad3-Ski for Therapeutic Development in Pancreatic Cancer

以 Smad3-Ski 为靶点进行胰腺癌治疗开发

• 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
• 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

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Smad 4的突变，最初称为胰腺癌4（Dpc-4）中的缺失，其发生在约50%的检查的人胰腺癌中。TGF-β与其跨膜受体结合导致Smad 2和Smad 3磷酸化，其与Smad 4形成异源三聚体复合物以抑制正常胰腺上皮细胞的生长。在胰腺癌细胞中，TGF-β诱导的生长抑制通过Smad 4的丢失或通过抑制Smad依赖性生长停滞而被阻止。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蛋白Ski过表达的抑制，Ski是一种已知直接与Smad结合以抑制信号传导的蛋白。11例胰腺癌标本中有9例Ski过表达，而9例正常胰腺标本中Ski不表达。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 of Surgery 246：61-68，2007）。Ski的过表达也与食管鳞状细胞癌、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，以测试的假设，药理学破坏的Ski-Smad相互作用将恢复TGF-β信号在Ski过表达的胰腺癌细胞。我们希望这些研究可能会为治疗某些胰腺癌带来新的治疗方法。我们已经确定了小的约束肽，称为肽适体，和一个小分子配体，抑制Smad 3-Ski结合。在具体目标1中，我们建议优化我们的初始适体试剂，用于破坏过表达Ski的胰腺癌细胞中的Smad-Ski相互作用，并定义Ski蛋白结合Smads上的“热点”。在具体目标2中，我们建议通过筛选可用的化学文库来靶向Ski结合热点以发现额外的小分子配体。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。 公共卫生关系：大多数接受目前治疗的胰腺癌患者仅存活3至6个月;这种疾病的总体5年生存率<5%。我们建议进行临床前研究，以评估胰腺癌细胞中的新治疗靶点，Ski-Smad蛋白相互作用。我们将使用肽适体和药物样化学物质来破坏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，Ski-Smad是新药开发的有效，可药用靶标，以帮助胰腺癌患者。