WT1 and beta-catenin targets in Wilms tumor

WT1 和 β-连环蛋白在肾母细胞瘤中的作用靶点

• 批准号: 7083588
• 负责人: Benjamin Tycko
• 金额: $ 37.27万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-01 至 2008-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7083588
• 关键词: Wilms' tumor; cadherins; carcinogenesis; clinical research; gene expression; human subject; immunoprecipitation; laboratory mouse; microarray technology; nephrogenesis; phosphorylation; tissue /cell culture; tumor suppressor genes

DESCRIPTION (provided by applicant): Major efforts have gone into identifying the targets of oncogenic transcription factors, but data from tissue culture experiments have seldom been vetted in primary cancers. Here we address this problem, using Wilms tumor as an experimental system. Wilms tumors occurring in Denys-Drash and WAGR syndromes carry inactivating mutations of the WT1 tumor suppressor gene. In contrast, WT1 mutations are rare in sporadic Wilms tumors. We have confirmed previous data indicating that mutations in beta-catenin (CTNNB1), a component of the Wnt signaling pathway that acts as an oncogene in many of the most common human malignancies, are restricted to the WT1-null tumors. We also find that these mutations are strikingly clustered at codon Ser45. By expression profiling we have identified a panel of genes that distinguish the WT1-null from WT1-positive tumors. This dataset should be a powerful tool to identify downstream targets of WT1 and beta-catenin/TCF, which we hypothesize are enriched among these differentially expressed genes. Aim 1. We will determine whether the Wnt/beta-catenin signaling axis is universally activated in the WT1- null class of Wilms tumors. Aim 2. To narrow the list of WT1 and beta-catenin target genes, we will manipulate WT1 levels, and components of the beta-catenin pathway in tissue culture, and compare the results with our "gold standard" data from the primary Wilms tumors. Aim 3. To validate the candidate beta-catenin target genes in vivo, we will express mutant beta-catenin to the developing kidney, using a gene knock-in approach. By creating an isogenic series, these mice will also allow us to assay for the relative potency of mutation at Ser45 vs. other phosphorylation sites in affecting the proliferative/oncogenic potency of beta-catenin. We will subsequently cross these mice with Wt1-mutant heterozygotes, possibly generating a mouse model for Wilms tumor.

描述（由申请人提供）：主要努力致力于确定致癌转录因子的靶标，但来自组织培养实验的数据很少在原发性癌症中进行审查。在这里，我们使用维尔姆斯肿瘤作为实验系统来解决这个问题。 Denys-Drash 和 WAGR 综合征中发生的肾母细胞瘤携带 WT1 肿瘤抑制基因的失活突变。相比之下，WT1 突变在散发性肾母细胞瘤中很少见。我们已经证实之前的数据表明，β-连环蛋白 (CTNNB1) 的突变仅限于 WT1 缺失的肿瘤，β-连环蛋白 (CTNNB1) 是 Wnt 信号通路的一个组成部分，在许多最常见的人类恶性肿瘤中充当癌基因。我们还发现这些突变惊人地聚集在密码子 Ser45 处。通过表达谱分析，我们鉴定了一组区分 WT1 缺失肿瘤和 WT1 阳性肿瘤的基因。该数据集应该是识别 WT1 和 β-catenin/TCF 下游靶标的强大工具，我们假设这些靶标在这些差异表达基因中丰富。目标 1. 我们将确定 Wnt/β-连环蛋白信号轴是否在 WT1-null 类肾母细胞瘤中普遍激活。目标 2. 为了缩小 WT1 和 β-catenin 靶基因的范围，我们将在组织培养物中操纵 WT1 水平和 β-catenin 通路的组成部分，并将结果与​​来自原发性肾母细胞瘤的“金标准”数据进行比较。目标 3. 为了在体内验证候选 β-连环蛋白靶基因，我们将使用基因敲入方法向发育中的肾脏表达突变的 β-连环蛋白。通过创建同基因系列，这些小鼠还将允许我们分析 Ser45 突变与其他磷酸化位点在影响 β-连环蛋白增殖/致癌效力方面的相对效力。随后，我们将这些小鼠与 Wt1 突变杂合子杂交，可能产生肾母细胞瘤小鼠模型。