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Klf4 in tumor initiation and maintenance of squamous cell carcinoma

Klf4在鳞状细胞癌肿瘤发生和维持中的作用

基本信息

批准号：
7998180
负责人：
John Michael Ruppert
金额：
$ 27万
依托单位：
WEST VIRGINIA UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-03-01 至 2011-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7998180
关键词：
Acetylation Acetylglucosamine Affect Alleles Animal Model Anthracenes Antibodies Beryllium Binding Binding Sites Breast Carcinogens Cell Cycle Cell Nucleus Cells Chimeric Proteins Chromatin Codon Nucleotides Complementary DNA Cultured Cells Cyclin D1 Cytokeratin DNA Binding Development Dominant-Negative Mutation Dysplasia EP300 gene Elements Enzymes Epithelial Epithelial Cells Event Frequencies Genetic Transcription Genetically Engineered Mouse Genetically Modified Animals Goals Growth HRAS gene Half-Life Histologic Human Hyperplasia In Situ In Vitro Incidence Indium Keratin Ligands Link MCF10A cells Maintenance Malignant Neoplasms Mammary gland Maps Mediating Messenger RNA MicroRNAs Modeling Modification Molecular Mouse Mammary Tumor Virus Mus Mutagenesis Mutation Neoplasms Nuclear Oncogenes Open Reading Frames Oral Pathogenesis Pathway interactions Physiologic pulse Post-Translational Protein Processing Prevention Proteins RNA RNA analysis Regulation Research Personnel Role Run-On Assays Sequence Analysis Skin Skin Neoplasms Small Interfering RNA Squamous cell carcinoma Staining method Stains Structure Testing Tetanus Helper Peptide Tetracyclines Tissues Transactivation Transcript Transgenes Transgenic Mice Tumor Cell Line Untranslated Regions Up-Regulation Wild Type Mouse cell fate specification cell growth cell type chromatin remodeling dimethylbenzanthracene gain of function in vivo loss of function malignant breast neoplasm mouse model mutant neoplastic cell notch protein novel programs promoter protein function protein protein interaction skin squamous cell carcinoma transcription factor tumor tumor growth tumor initiation tumor progression tumorigenesis

项目摘要

The KLF4 transcription factor is important in cell fate and differentiation of epithelial cells. KLF4 rapidly initiates cutaneous squamous cell carcinoma (SCC) in mice, and is deregulated at an early step in human skin tumor progression. Using a conditional KLF4-ER fusion protein, we identified the cell fate determinant Notch 1 as a transcriptional target of KLF4. In cultured cells, in transgenic mice and in human tumors, KLF4 expression is associated with expression of Notchl, Notchl ligands, and Notchl effectors such as Cyclin D1. Transformation of RK3E epithelial cells requires Notchl. These studies identify a KLF4-Notch1 pathway that appears important in cell fate specification of normal epithelial cells and tumor cells. Mutagenesis of KLF4 identified dominant negative (DN) alleles that block transformation in vitro by KLF4. KLF4-DNs identify a role of KLF4 in growth of specific human cell types in vitro, and in transformation by specific transforming oncogenes such as ErbB2 and c-MYC. To study the role of Klf4 in cutaneous SCC we developed a novel highly penetrant model of SCC by administering carcinogens to genetically-engineered mice. Tumors were histologically similar to human SCC, and expressed SCC markers such as p53, keratin 14, and Notch! SCCs that developed in this model included KLF4-positive tumors and some tumors that were KLF4-negative. To understand the mechanisms that normally regulate KLF4, we will study the role of posttranslational modifications in the DN activity of mutant KLF4 proteins (Aim 1). The role of endogenous Klf4 in tumor initiation and maintenance will be studied in the new SCC mouse model using conditional, Cre-mediated deletion of Klf4/LoxP alleles, and by tetracycline-inducible expression of siRNA or KLF4-DN in transgenic mice (Aim 2). Using similar loss- and gain-of-function strategies, the role of Klf4 in mammary epithelial development and in transformation by ErbB2 will be determined (Aim 3). In Aim 4, a posttranslational control that appears responsible for upregulation of Klf4 transcripts in mouse and human SCC will be analyzed by identifying RNA destabilizing elements in the KLF4 cDNA. These studies may provide support of a role for KLF4 and Notchl in pathogenesis of common human cancers such as SCC and breast cancer. Thus, completion of the studies would identify this pathway as a target for prevention and treatment, and provide new animal models in which to assess such therapies.

KLF4转录因子在细胞命运和上皮细胞分化中起重要作用。KLF4快速在小鼠中引发皮肤鳞状细胞癌(SCC)，并在人类的早期阶段解除管制皮肤肿瘤进展。使用条件性KLF4-ER融合蛋白，我们鉴定了细胞命运决定因素 Notch 1作为KLF4的转录靶点。在培养细胞、转基因小鼠和人类肿瘤中，KLF4 Notchl的表达与Notchl、Notchl配体和Notchl效应因子(如Cyclin D1)的表达有关。 RK3E上皮细胞的转化需要Notchl。这些研究确定了KLF4-Notch1途径在正常上皮细胞和肿瘤细胞的细胞命运决定中具有重要意义。 KLF4的诱变鉴定出显性负性(DN)等位基因，可阻断KLF4的体外转化。 KLF4-DNS鉴定KLF4在特定人类细胞类型的体外生长和转化中的作用特异性转化癌基因，如ErbB2和c-myc。为了研究KLF4在皮肤鳞状细胞癌中的作用，我们建立了一种新的高渗透皮肤鳞状细胞癌模型。给转基因小鼠注射致癌物质。肿瘤在组织上与人类相似并表达鳞癌标志物P53、角蛋白14和Notch！在此模型中开发的SCCS 包括KLF4阳性的肿瘤和一些KLF4阴性的肿瘤。为了了解正常调节KLF4的机制，我们将研究翻译后的作用突变的KLF4蛋白的dN活性的修饰(目标1)。内源性KLF4在肿瘤中的作用在新的鳞状细胞癌小鼠模型中，将使用条件的、Cre介导的方法来研究启动和维持 KLF4/loxP等位基因的缺失以及四环素诱导的转基因小干扰RNA或KLF4-dN的表达小鼠(目标2)。使用类似的功能丧失和功能获得策略，KLF4在乳腺上皮中的作用将确定ErbB2的发展和转型(目标3)。在《目标4》中，翻译后控制对小鼠和人鳞状细胞癌中Klf4转录上调负责的基因将进行分析鉴定KLF4基因中的RNA不稳定元件。这些研究可能为KLF4和Notch1在普通人发病机制中的作用提供支持鳞状细胞癌和乳腺癌等癌症。因此，研究的完成将确定这条路径是一条为预防和治疗提供目标，并提供评估此类疗法的新动物模型。