Dissecting the role of TCF7L1 in colorectal cancer

剖析 TCF7L1 在结直肠癌中的作用

基本信息

批准号：
10040673
负责人：
Gregory S. Yochum
金额：
$ 15.83万
依托单位：
PENNSYLVANIA STATE UNIV HERSHEY MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-10 至 2022-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10040673
关键词：
Accounting Address Anchorage-Independent Growth Binding Binding Sites Biological Assay Cancer Cell Growth Cancer Etiology Cell Cycle Cell Cycle Progression Cell Nucleus Cell Proliferation Cells Cessation of life ChIP-seq Chromatin Clinic Clinical Management Colorectal Cancer Colorectal Neoplasms Complementary DNA Complex Consensus DNA DNA Binding DNA Binding Domain Data Development Disease Elements Enhancers Family Family member Future Gene Expression Genes Genetic Enhancer Element Genetic Transcription Genomic approach Growth Health Human In Vitro Individual Knowledge Lead Lesion Literature Microarray Analysis Mitotic Cell Cycle Modeling Molecular Mucous Membrane Mutation Nuclear Oncogenes Oncogenic Operative Surgical Procedures Pathologic Pathway interactions Patients Point Mutation Prevalence Publishing Recurrent disease Regulation Regulator Genes Regulatory Element Reporting Research Residual Tumors Role Signal Pathway Signal Transduction Surveys System TCF Transcription Factor TCF7L2 gene Therapeutic Therapeutic Intervention Tissues Transcript Transcription Coactivator Transcription Repressor Tumorigenicity United States WNT Signaling Pathway Work advanced disease beta catenin c-myc Genes cancer cell carcinogenesis cell growth cellular transduction chemotherapy colon cancer cell line colon cancer patients colon carcinogenesis design differential expression effective therapy functional genomics genetic signature genome-wide in vivo inhibitor/antagonist knock-down member mortality mutant novel programs recruit small hairpin RNA targeted treatment transcription factor transcriptome transcriptome sequencing treatment strategy tumor tumorigenesis vector

项目摘要

PROJECT SUMMARY Deregulated Wnt/β-catenin signaling is a common feature of colorectal cancer (CRC), but how this pathway corrupts target gene expression is not fully understood. The T-cell factor/Lymphoid enhancer factor (TCF/Lef; hereafter TCF) transcription factors bind Wnt-responsive DNA elements (WREs) to control Wnt/β-catenin target gene expression. Of the four TCF family members (TCF7, LEF1, TCF7L1, and TCF7L2) very little is known about TCF7L1 in CRC and the set of target genes it directly regulates. By using shRNAs to deplete TCF7L1 in established human CRC lines, we found that it promotes cell growth. Although microarray analysis of transcripts differentially expressed in TCF7L1 knockdown cells versus controls uncovered hundreds of genes, surprisingly, we failed to identify a Wnt target gene signature among this list. Moreover, published ChIP-Seq data indicates that a substantial fraction of TCF-bound DNA elements lack consensus TCF binding motifs. These findings suggest that TCF7L1 may primarily function outside the canonical Wnt signaling pathway to promote oncogenesis. Additional work is needed to identify the constellation of direct target genes that TCF7L1 regulates and whether its DNA-binding function is required to promote CRC growth. In Aim 1, we will identify the TCF7L1-transcriptome by conducting unbiased and genome-wide functional genomics approaches in control and TCF7L1-depleted CRC cells. In TCF7L1-depleted lines, we will introduce wild-type and DNA-binding deficient TCF7L1 cDNAs to classify targets whose expression is regulated independently of direct TCF7L1 binding to DNA. In Aim 2, we will determine whether the DNA-binding capacity of TCF7L1 is required for CRC cell proliferation, progression through the cell cycle, growth in an anchorage-independent manner, and tumorigenesis in vivo. We will also assess whether non-canonical targets are differentially expressed in primary human colonic tissues and tumors. The vast majority of existing therapeutics designed to target the Wnt pathway have focused on nuclear TCF/β-catenin complexes as the key regulator of the CRC transcriptome. Our findings will establish TCF7L1 as a critical regulator of genes outside the canonical Wnt/β- catenin pathway and will open a whole new field of research to exploit those targets for therapeutic intervention.

项目概要 Wnt/β-连环蛋白信号传导失调是结直肠癌 (CRC) 的一个常见特征，但该通路如何发挥作用 T 细胞因子/淋巴增强因子 (TCF/Lef；下文称为 TCF）转录因子结合 Wnt 响应 DNA 元件 (WRE) 来控制 Wnt/β-catenin 四个 TCF 家族成员（TCF7、LEF1、TCF7L1 和 TCF7L2）中很少有目标基因表达。通过使用 shRNA 来消除 CRC 中的 TCF7L1 及其直接调节的靶基因组。通过微阵列分析，我们发现 TCF7L1 在已建立的人类 CRC 系中促进细胞生长。 TCF7L1 敲低细胞与对照细胞中差异表达的转录本发现了数百个令人惊讶的是，我们未能在此列表中识别出 Wnt 目标基因签名。 ChIP-Seq 数据表明很大一部分 TCF 结合 DNA 元件缺乏一致的 TCF 结合这些发现表明 TCF7L1 可能主要在经典 Wnt 信号传导之外发挥作用。需要进行额外的工作来确定直接靶基因群。在目标 1 中，我们了解 TCF7L1 的调节作用以及其 DNA 结合功能是否是促进 CRC 生长所必需的。将通过进行公正的全基因组功能基因组学来鉴定 TCF7L1 转录组对照和 TCF7L1 耗尽的 CRC 细胞中的方法在 TCF7L1 耗尽的细胞系中，我们将引入野生型。和 DNA 结合缺陷的 TCF7L1 cDNA 对表达独立调节的靶标进行分类在目标 2 中，我们将确定 TCF7L1 的 DNA 结合能力是否为直接 TCF7L1 与 DNA 的结合。 CRC 细胞增殖、细胞周期进展、不依赖贴壁的生长所需我们还将评估非典型靶点是否存在差异。绝大多数现有疗法旨在表达于原代人类结肠组织和肿瘤中。以 Wnt 通路为目标，重点关注核 TCF/β-catenin 复合物作为 CRC 的关键调节因子我们的研究结果将确立 TCF7L1 作为经典 Wnt/β- 之外基因的关键调节因子。连环蛋白途径，并将开辟一个全新的研究领域，以利用这些目标进行治疗干涉。