Dissecting the role of DNA damage repair deficiency in Ewing sarcoma pathogenesis for improved risk stratification and treatment

项目摘要 尤文肉瘤是影响儿童的第二大常见骨和软组织癌症， 全世界的青少年。它是一种侵袭性恶性肿瘤，需要多模式治疗， 发病率以及转移性和复发性疾病的治愈率仍然很低。虽然尤文肉瘤是 特征和驱动EWSR 1-ETS基因融合，生物因素有助于这些简单的 重排，和复杂的重排称为chromosomal在一个子集的情况下，是不好的， 表征了我发现FANCC和其他DNA损伤修复（DDR）中的遗传致病性变体 相对于其他儿科肉瘤亚型，尤文肉瘤患者中的基因是独特富集的 （Gillani等人，AJHG 2022）。我们还需要做很多工作来了解DNA损伤修复缺陷是如何发生的。 有助于尤文肉瘤发病机制。这项研究建议的指导假设是， 损伤修复缺陷促进尤文肉瘤的发病机制，表现为一种独特的模式， 易感生殖系变异和肿瘤基因组特征是肿瘤发生的组成部分， 用于更知情的风险分层和治疗。 我们将应用计算和实验方法对来自患有以下疾病的患者的数据集进行测序： 尤文肉瘤和细胞系模型来完成这一研究建议。在具体目标1中，我们将剖析 尤文肉瘤中影响DDR基因的较大种系结构变异的附加作用 分析了301名父母-先证者三人组，并评估了生殖系结构变异的富集， 1180例相对于无癌对照。在具体目标2中，我们将定义FANCC变体的表型 在尤文肉瘤患者的生殖系中发现，并将这些变体敲入间充质干细胞系， 了解它们如何在遗传毒性应激的存在下促进基因组不稳定性。在具体目标3中， 我们将推导出基因组特征，以进一步了解DNA损伤过程， 尤文肉瘤肿瘤和相关的拷贝数签名，特别是与治疗反应， 复发最后，我们将进行体外药物治疗研究，以证明特定复制的效用。 作为对DNA损伤应答靶向剂敏感性的生物标志物的数字签名。 通过跨越生殖系和肿瘤的综合研究，我们打算推动新的 了解DNA损伤在尤文肉瘤发病机制中的作用， 改善这种侵袭性儿科癌症的风险分层和治疗。此外，在扩大我们的 更广泛地了解生殖系结构变异，杂合风险变异在癌症中的作用 易感性和拷贝数标记作为临床相关的生物标志物，这项工作也将具有很高的临床应用价值。 与其他儿科癌症的关系。

PROJECT SUMMARY Ewing sarcoma is the second most common bone and soft tissue cancer impacting children and adolescents worldwide. It is an aggressive malignancy requiring multimodal treatment that confers significant morbidity, and cure rates for metastatic and relapsed disease remain poor. While Ewing sarcoma is characterized and driven by EWSR1-ETS gene fusions, the biological factors contributing to these simple rearrangements, and complex rearrangements known as chromoplexy in a subset of cases, are not well- characterized. I found that inherited pathogenic variants in FANCC and other DNA damage repair (DDR) genes are uniquely enriched among patients with Ewing sarcoma relative to other pediatric sarcoma subtypes (Gillani et al., AJHG 2022). Much work is still needed to understand how DNA damage repair deficiency contributes to Ewing sarcoma pathogenesis. The guiding hypothesis of this research proposal is that DNA damage repair deficiency promotes Ewing sarcoma pathogenesis, manifesting as a unique pattern of predisposing germline variants and tumor genomic features that are integral to oncogenesis and can be utilized for more informed risk stratification and treatment. We will apply computational and experimental approaches to sequencing datasets from patients with Ewing sarcoma and cell line models to complete this research proposal. In Specific Aim 1, we will dissect the additive contribution of larger germline structural variants impacting DDR genes in Ewing sarcoma by analyzing a cohort of 301 parent-proband trios and evaluating the enrichment of germline structural variants in 1180 cases relative to cancer-free controls. In Specific Aim 2, we will define the phenotype of FANCC variants seen in the germline of Ewing sarcoma patients and knock these variants into mesenchymal stem cell lines to understand how they contribute to genomic instability in the presence of genotoxic stress. In Specific Aim 3, we will derive genomic signatures to gain additional insight into the DNA damage processes that are operant in Ewing sarcoma tumors and associate copy number signatures specifically with treatment response and relapse. Finally, we will conduct in-vitro drug treatment studies to demonstrate the utility of specific copy number signatures as biomarkers of sensitivity to DNA damage response targeting agents. Through integrative investigations spanning the germline and tumor, we intend to drive new understanding of how DNA damage operates in Ewing sarcoma pathogenesis, knowledge that will be central to improved risk stratification and treatment of this aggressive pediatric cancer. Moreover, in extending our broader understanding about germline structural variants, the role of heterozygous risk variants in cancer predisposition, and copy number signatures as clinically relevant biomarkers, this work will also have high relevance to other pediatric cancers.