The Role of MCM7 in Neuroblastoma Tumorigenesis

MCM7 在神经母细胞瘤肿瘤发生中的作用

• 批准号: 6768804
• 负责人: JASON M SHOHET
• 金额: $ 13.4万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 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 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6768804
• 关键词: DNA binding protein; DNA replication; carcinogenesis; flow cytometry; fluorescent in situ hybridization; gene expression; gene expression profiling; genetic transcription; genetically modified animals; histology; immunocytochemistry; laboratory mouse; neoplasm /cancer genetics; neuroblastoma; oncogenes; pediatric neoplasm /cancer; plasminogen activator; polymerase chain reaction; protein protein interaction; protein structure function; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant): Neuroblastoma is the most common extra-cranial solid tumor in children, accounting for 15% of all pediatric cancer deaths despite modern dose-intensive chemotherapy. Improvements in therapy will come from a deeper understanding of the biology of this cancer. Clinical and biological risk stratification identifies the MYCN oncogene as the sole reliable marker for high-risk disease. MYCN is amplified in 25-35% of cases and distinguishes a subset of patients with highly aggressive disease and poor prognosis. The MYCN protein is a bHLH leucine zipper nuclear protein that forms heterodimers with the MAX protein and binds to DNA acting as both a transcriptional activator and repressor. However, direct downstream targets of MYCN connecting its overexpression to the particularly malignant phenotype remain undefined. Using gene expression profiling and subtractive hybridization we have identified a series of MYCN regulated genes. One of these genes, MCM7 is the focus of this proposal. MCM7 is a direct transcriptional target of MYCN with essential functions regulation DNA replication in S-phase. This gene interacts with several important regulatory molecules including Rb and MAT1 kinase. We have shown that MCM7 expression closely correlates with MYCN amplification in vivo and that it alters gene transcription in a cell culture system. The central hypothesis of this proposal is that aberrant expression of MCM7 mediates at least some of the transformative and malignant consequences of MYCN oncogene amplification through alterations in DNA synthetic processes, induction of chromosomal instability, or secondary changes in gene transcription mediated by its interaction with other non-MCM proteins. The specific aims of this proposal will pursue this hypothesis and test whether MCM7 is a good target for novel therapeutic interventions as follows: Specific Aim I will test whether inhibition of MCM7 function will influence the growth and metastasis of neuroblastoma cell lines. Specific Aim II will characterize the mechanism and specificity of chromosomal instability induced by overexpression of MCM7. Specific Aim III will evaluate phenotypic changes and tumor incidence in transgenic mice with tissue specific constitutive overexpression of MCM7.

描述（申请人提供）：神经母细胞瘤是儿童最常见的颅外实体瘤，尽管采用现代剂量强化化疗，但仍占所有儿童癌症死亡人数的15%。治疗的改进将来自于对这种癌症的生物学的更深入的了解。临床和生物学风险分层将MYCN癌基因确定为高危疾病的唯一可靠标志物。MYCN在25-35%的病例中扩增，并区分出高侵袭性疾病和预后差的患者亚群。MYCN蛋白是一种bHLH亮氨酸拉链核蛋白，与MAX蛋白形成异源二聚体，并与DNA结合，作为转录激活因子和抑制因子。然而，MYCN的直接下游目标将其过度表达与特别的恶性表型联系起来仍然不明确。通过基因表达谱和减法杂交，我们鉴定了一系列MYCN调控基因。其中一个基因，MCM7是这个提议的重点。MCM7是MYCN的直接转录靶点，具有调节s期DNA复制的基本功能。该基因与几个重要的调控分子相互作用，包括Rb和MAT1激酶。我们已经证明MCM7的表达与MYCN在体内的扩增密切相关，并在细胞培养系统中改变基因转录。该建议的中心假设是，MCM7的异常表达通过改变DNA合成过程、诱导染色体不稳定性或与其他非mcm蛋白相互作用介导的基因转录的继发性变化，介导了MYCN癌基因扩增的至少一些转化和恶性后果。本课题的具体目的将继续研究这一假设，并检验MCM7是否为新型治疗干预的良好靶点：具体目的：我将检验抑制MCM7功能是否会影响神经母细胞瘤细胞系的生长和转移。特异性Aim II将描述MCM7过表达诱导染色体不稳定性的机制和特异性。Specific Aim III将评估MCM7组织特异性组成型过表达转基因小鼠的表型变化和肿瘤发生率。