PAX3/FKHR IN ALVEOLAR RHABDOMYOSARCOMA

肺泡型横纹肌肉瘤中的 PAX3/FKHR

• 批准号: 6103243
• 负责人: DAVID N SHAPIRO
• 金额: $ 19.77万
• 依托单位: ST. JUDE CHILDREN'S RESEARCH HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-06-01 至 2000-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6103243
• 关键词: chimeric proteins; gene expression; genetically modified animals; laboratory mouse; laboratory rabbit; molecular cloning; molecular oncology; neoplasm /cancer genetics; neoplastic transformation; oncoproteins; protein structure function; rhabdomyosarcoma; tissue /cell culture; transcription factor; transfection

Rhabdomyosarcoma, a malignant tumor of skeletal muscle, is the most common soft tissue sarcoma of childhood. Approximately 35% of cases have an alveolar histiotype and a (2;13) translocation, which tends to be associated with a more aggressive clinical course. This rearrangement creates a fusion protein involving the developmentally regulated PAX3 transcription factor and a ubiquitously expressed member of the forkhead family of transcription factors, designated FKHR. Preliminary studies have shown that PAX3/FKHR can function both as a transcriptional activator and a potent inhibitor of myogenesis, relying on DNA-binding domains from PAX3 and the novel FKHR activation domain. Cellular transformation by the chimera depends absolutely on the presence of FKHR structural motifs, whereas DNA binding through the PAX3 paired domain appears dispensable, indicating that oncogenesis may not proceed through activation of PAX3 target genes. To precisely understand how the fusion protein contributes to neoplastic transformation of myogenic cells, we propose to define the contribution of each of its distinct domains to the modulation of gene expression. First, the structural components of PAX3/FKHR essential for in vitro cellular transformation will be identified and then tested for their capacity to induce tumors in vivo by targeting their expression to the myogenic precursors of transgenic mice. Second, interacting proteins that associate with these functionally important PAX3/FKHR domains will be evaluated for their capacity to influence the in vitro transforming potential of the fusion protein. A final goal will be to delineate the biologic pathways regulated by PAX3/FKHR through identification of genes that are specifically modulated by enforced expression of the fusion protein and are essential for tumorigenesis. Results of these studies should fill in the entire pathway from t(2;13)-mediated creation of the PAX3/FKHR oncoprotein to its aberrant activation of downstream targets and modulation of biologic pathways, culminating in overt tumor development. Improved understanding of the mechanisms responsible for cellular transformation by PAX3/FKHR will yield important information about the regulatory circuits disrupted by its expression in myogenic cells and may suggest novel approaches for the treatment of this often resistant tumor.

横纹肌肉瘤是骨骼肌的一种恶性肿瘤，是最常见的 儿童常见软组织肉瘤。大约35%的病例有 肺泡组织型和(2；13)易位，这往往是 与更具侵略性的临床病程有关。这种重新安排 产生一种涉及发育调节的PAX3的融合蛋白 转录因子和叉头的一个普遍表达的成员 转录因子家族，命名为FKHR。初步研究 已经证明PAX3/FKHR既可以作为转录因子发挥功能，也可以作为转录因子 依赖DNA结合的肌肉发生的激活剂和有效的抑制物 来自PAX3的结构域和新的FKHR激活结构域。蜂窝 嵌合体的转化完全取决于FKHR的存在 结构基序，而DNA通过PAX3配对结构域结合 似乎是可有可无的，这表明肿瘤发生可能不会通过 激活PAX3靶基因。为了准确地了解核聚变是如何 蛋白质有助于肌源性细胞的肿瘤性转化 建议定义其每个不同领域对 基因表达的调节。第一，建筑的结构组成 Pax3/FKHR对体外细胞转化至关重要 鉴定并测试它们在体内诱发肿瘤的能力 通过靶向转基因成肌前体细胞的表达 老鼠。第二，与这些相关的相互作用的蛋白质 将评估具有重要功能的PAX3/FKHR域 影响融合蛋白体外转化潜能的能力 蛋白。最终的目标将是描绘出生物途径 受PAX3/FKHR调控的基因 通过强制表达融合蛋白和 对于肿瘤的发生是必不可少的。这些研究的结果应该填满 在t(2；13)介导的PAX3/FKHR产生的整个途径中 癌蛋白对其下游靶点的异常激活和 生物通路的调节，最终导致显性肿瘤的发展。 提高对细胞致病机制的理解 PAX3/FKHR的转换将产生有关 它在肌源性细胞中的表达扰乱了调控电路，并可能 提出治疗这种经常耐药的肿瘤的新方法。