Truncated GLI1 In Glioblastoma

胶质母细胞瘤中 GLI1 截短

基本信息

批准号：
8673663
负责人：
HUI-WEN LO
金额：
$ 2.03万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-04-15 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8673663
关键词：
Address Adult Affect Alternative Splicing Binding Biology Brain Codon Nucleotides DNA Elements Engineering Erinaceidae Exons Family GLI gene Gene Expression Gene Targeting Genes Genetic Transcription Glioblastoma Goals Growth Health Human Infiltration Investigation Knock-in Mouse Knowledge Laboratories Ligands Light Malignant - descriptor Malignant Neoplasms Malignant neoplasm of brain Mediating Mediator of activation protein Messenger RNA Molecular Monitor Mus Normal tissue morphology Nuclear Pathway interactions Patients Pattern Phenotype Process Proteins RNA Binding RNA Splicing Role Signal Transduction Specimen Survival Rate Testing Vascular Endothelial Growth Factor Receptor-2 Vascular Endothelial Growth Factors Xenograft procedure Zinc Fingers angiogenesis base cis acting element clinically relevant gain of function insight knock-down mRNA Precursor malignant phenotype mouse model novel nucleocytoplasmic transport overexpression promoter public health relevance transcription factor tumor tumor growth vector control

项目摘要

DESCRIPTION (provided by applicant): Alternative splicing is observed in ~40-60% of human genes; however, its full impact on human cancers is still not well understood. In this proposal, we will functionally characterize a novel, alternatively spliced transcription factor discovered in the PI's laboratory, namely, tGLI1 (truncated glioma-associated oncogene homolog 1). Belonging to the GLI1 family of zinc finger transcription factors, tGLI1 has an in-frame deletion of entire exon 3 and part of exon 4 of the GLI1 gene. Like GLI1, tGLI1 responds to sonic hedgehog ligand, undergoes nuclear transport, and regulates known GLI1 target genes. However, our preliminary results showed that tGLI1 may differ from GLI1 in regulating tumor phenotypes, transcriptional targets and expression pattern. Glioblastoma multiforme (GBM) xenografts engineered to express tGLI1 appeared to be more aggressive in growth, invasiveness, and angiogenesis than those with GLI1. tGLI1 has gained the ability to enhance expression of several invasion- and angiogenesis-promoting genes. tGLI1 was highly expressed in nearly 50% of GBM specimens we had examined, but undetectable in normal brain or other normal tissues. These observations have led us to hypothesize that the novel tGLI1 transcription factor behaves as a gain-of-function GLI1 that regulates expression of a unique set of genes not targeted by GLI1, and that because of its overexpression in GBM and its ability to enhance genes important for tumor growth, invasion and angiogenesis, tGLI1 supports some of the predominant features of GBM, i.e. high degrees of proliferation, infiltration and vascularity. Three Specific Aims are proposed to test this hypothesis. (1) Determine whether tGLI1 mediates malignant phenotypes of GBM. There has been no systematic study that investigated the role of tGLI1 in distinctive GBM malignant phenotypes. Here, we will create intracranial GBM xenografts with differential levels of tGLI1 via knock-in and knock-down approaches, examine the xenografts for growth, invasiveness and angiogenesis, and monitor the xenograft-carrying mice for survival. (2) Elucidate the mechanisms by which tGLI1 regulates gene expression in GBM. tGLI1 has gained the ability to enhance expression of several genes; however, the underlying mechanisms for this unique ability is currently unknown. Here, we will investigate two potential mechanisms: a) tGLI1 binds to unique DNA elements, not recognized by GLI1, within its target gene promoters and thereby regulates genes not targeted by GLI1; and b) tGLI1 has gained the ability to interact with transcription regulators that do not interact with GLI1, thereb regulating genes not targeted by GLI1. (3) Investigate alternative splicing process that leads to tGLI1 mRNA synthesis in GBM. Alternative splicing process for tGLI1 mRNA synthesis is presently unknown. We will identify the cis-acting elements within the pre-mRNA and the RNA-binding splicing factors that together mediate alternative splicing for tGLI1 mRNA synthesis. Our study will be the first step towards defining tGLI1 as a novel mediator of GBM malignancy, and understanding the full spectrum of tGLI1 functionality and the molecular basis for tGLI1 mRNA synthesis.

描述（由申请人提供）：在约40-60％的人类基因中观察到替代剪接；但是，它对人类癌症的全部影响仍然不太了解。在此提案中，我们将在功能上表征一个新颖的，剪接的转录因子 PI的实验室，即TGLI1（截短神经胶质瘤相关的癌基因同源1）。 TGLI1属于锌指转录因子的Gli1家族，具有整个外显子3的框架缺失，并且是Gli1基因的外显子4的一部分。像Gli1一样，TGLI1对Sonic Hedgehog配体反应，经历核转运，并调节已知的Gli1靶基因。但是，我们的初步结果表明，在调节肿瘤表型，转录靶标和表达模式方面，TGLI1可能与GLI1有所不同。与具有GLI1的胶质母细胞瘤多形式（GBM）异种移植物设计为表达TGLI1的异种移植物在生长，侵入性和血管生成上似乎更具侵略性。 TGLI1已获得增强几种侵袭和血管生成基因表达的能力。 TGLI1在我们检查过的近50％的GBM标本中高度表达，但在正常脑或其他正常组织中无法检测到。这些观察结果使我们假设新型的TGLI1转录因子的表现是一种功能性GLI1，它调节表达不受GLI1靶向的独特基因的表达，并且由于其在GBM中的过表达及其在GBM中的过表达及其对肿瘤生长，入侵，入侵，TGLI的高度deporse somimint of of themant of temins of of themant的能力增殖，浸润和血管性。提出了三个特定目标来检验这一假设。（1）确定TGLI1是否介导GBM的恶性表型。没有系统的研究研究TGLI1在独特的GBM恶性表型中的作用。在这里，我们将通过敲门和敲门方法创建具有TGLI1差异水平的颅内GBM异种移植物，检查异种移植物的生长，侵袭性和血管生成，并监测携带异种移植小鼠的生存。（2）阐明TGLI1调节GBM基因表达的机制。 TGLI1已获得增强几种基因表达的能力。但是，目前尚不清楚这种独特能力的基本机制。在这里，我们将研究两种潜在的机制：a）TGLI1在其靶基因启动子内与GLI1识别的独特DNA元素结合，从而调节GLI1未靶向的基因； b）TGLI1已获得与不与GLI1相互作用的转录调节剂相互作用的能力，并因此调节了GLI1靶向的基因。（3）研究导致GBM中TGLI1 mRNA合成的替代剪接过程。目前未知TGLI1 mRNA合成的替代剪接过程。我们将确定前MRNA中的顺式作用元件和RNA结合剪接因子，共同介导TGLI1 mRNA合成的替代剪接。我们的研究将是将TGLI1定义为GBM恶性肿瘤的新介体的第一步，并了解TGLI1功能的完整范围以及TGLI1 mRNA合成的分子基础。