Dissecting the contribution of the transcriptional regulators of SNS fate to neuroblastoma oncogenesis

项目概要/摘要： 神经母细胞瘤（NB）是婴儿期最常见的癌症，起源于交感神经系统的未成熟细胞。 神经系统（SNS），其来源于神经嵴干细胞（NCC）。NB负责15%的儿科 癌症死亡，大多数高风险NB患者最终复发耐药疾病。找到 对于高风险的神经母细胞瘤，迫切需要新的治疗方法，特别是对于复发疾病。的 神经母细胞瘤起始的标准模型假定分化受阻。我们建议SNS因素 重要的生长和建立的SNS是增选的神经母细胞瘤突变， 支持肿瘤的生长和建立。进一步根据我们的初步研究结果，我们提出了一个 一类被称为BET抑制剂的药物，被发现对神经母细胞瘤非常有效，部分 通过抑制重要的SNS因素发挥作用。在这里，我们假设SNS细胞命运调节因子， 对于NB肿瘤发生至关重要，并且负责NB对BET抑制剂的敏感性。我们的两个目标 目标1：NB中BET抑制的细胞命运调节剂是关键目标吗？目标二： 细胞特性/发育阶段是否有助于原发性NCC的恶性转化？第一 我们的目的是在神经母细胞瘤细胞系中确定BET抑制剂是否通过关闭关键的SNS起作用 因素因此，在这里我们将：1）询问BET抑制剂对SNS谱系因子表达的影响。（二） 研究在人NB细胞系中响应BET抑制剂JQ 1的BET蛋白BRD 4结合的损失。 3)测试沉默SNS谱系因子单独或组合是否干扰人NB细胞的生长 线和NB肿瘤。4)确定JQ 1不敏感MSCV是否反式表达谱系因子 启动子在人NB细胞系和患者来源的异种移植肿瘤中传递对BET抑制剂的抗性。 目的1将确定SNS谱系因子是否是NB维持所必需的。在目标2中，我们将询问是否 这些因子在功能上是NB肿瘤发生所必需的。为了测试第二个目标，我们将使用一个独特的系统， 我们已经开发了将正常的未成熟SNS小鼠细胞（NCC）转化为神经母细胞瘤的方法， 重要的SNS因子是否有助于神经母细胞瘤的发生。对于第二个目标，我们将： 确定SNS核心因子是否阻断NCC分化为交感神经元。2)我们将确定是否 SNS核心转录因子促进体外致瘤行为。3)确定SNS核心是否 转录因子单独或与N-Myc联合促进NCC衍生的NB肿瘤的形成 或1 p36杂合性缺失，这是NB中两种常见的突变。总的来说，我们的工作将告诉我们， 对SNS发展重要的因素也有助于神经母细胞瘤。进一步提高我们的工程能力 来自未成熟SNS小鼠细胞的神经母细胞瘤肿瘤独特地使我们能够阐明神经母细胞瘤的新机制。 神经母细胞瘤对BET抑制的敏感性，并发现导致这种疾病的新遗传因素。

Project Summary/Abstract: Neuroblastoma (NB) is the most common cancer of infancy and arises from immature cells of the sympathetic nervous system (SNS) that derive from neural crest stem cells (NCCs). NB is responsible for 15% of pediatric cancer deaths with the majority of high-risk NB patients eventually relapsing with resistant disease. Finding novel treatments, especially for relapse disease, is desperately needed for high-risk neuroblastoma. The standard model of neuroblastoma initiation assumes a block in differentiation. We propose that SNS factors important for the growth and establishment of the SNS are co-opted by neuroblastoma mutations to instead support the growth and establishment of the tumor. Further based on our preliminary findings we propose a class of drugs called BET inhibitors, which were found to be very effective against neuroblastoma, partially function by suppressing important SNS factors. Here, we hypothesize that SNS cell fate regulators, are critical for NB oncogenesis and responsible for NB sensitivity to BET inhibitors. The two aims we will pursue in this proposal: Aim 1: Are regulators of cell fate critical targets of BET inhibition in NB? Aim 2: Does cell identity/developmental stage contribute to malignant transformation of primary NCCs? For the first aim we will determine in neuroblastoma cell lines, if BET inhibitors work through turning off critical SNS factors. Thus, here we will: 1) Interrogate the impact of BET inhibitors on SNS lineage factors expression. 2) Investigate loss of the BET protein BRD4 binding in response to the BET inhibitor JQ1, in human NB cell lines. 3) Test if silencing SNS lineage factors individually or in combination interferes with growth of human NB cell lines and NB tumors. 4) Determine if lineage factors expressed in trans from the JQ1-insensitive MSCV promoter conveys resistance to BET inhibitors in human NB cell lines and patient derived xenograft tumors. Aim 1 will establish if SNS lineage factors are necessary for NB maintenance. In Aim 2, we will interrogate if these factors are functionally required for NB oncogenesis. To test the second aim we will use a unique system we have developed for turning normal immature SNS mouse cells, the NCCs, into neuroblastoma to determine if the important SNS factors can contribute to initiating neuroblastoma. For the second aim we will: 1) Determine if the SNS core factors block NCC differentiation into sympathetic neurons. 2) We will determine if the SNS core transcription factors promote tumorigenic behavior in vitro. 3) Determine if the SNS core transcription factors promotes the formation of NCC-derived NB tumors alone or in combination with N-Myc or 1p36 loss of heterozygosity, two common mutations in NB. Overall, our work will inform us of whether factors important for SNS development also contribute to neuroblastoma. Further our ability to engineer neuroblastoma tumors from immature SNS mouse cells uniquely enables us to illuminate novel mechanisms of neuroblastoma sensitivity to BET inhibition and discover new genetic contributors to this disease.