Characterizing Chromatin Remodeling Mechanisms of Chemo-Sensitivity and Resistance in Pediatric Solid Tumors

项目总结 尽管已知染色质重塑复合体在导致20%以上的人类癌症中所起的作用，但 染色质重塑复合体在儿童实体瘤治疗反应中的作用 更少人理解。横纹肌样肿瘤的转化和进展需要残留的SWI/SNF活性。 然而，尚不清楚SWI/SNF及其对潜在表观基因组的影响是否具有治疗靶向性。 如果以这个复合体为目标的化合物会成功。此外，SWI/SNF还牵涉到 表观遗传抗性机制提示该复合体可能既能赋予敏感性，又能 耐药性取决于癌症的背景。融合阳性的肺泡型横纹肌肉瘤(ARMS)收益 化疗耐药性，而不是同时获得突变来驱动这种耐药性。这些数据表明 武器复发可能是由表观遗传机制驱动的。因此，这项研究的总体目标是 明确染色质结构在横纹肌样瘤治疗敏感性中的作用(目标1)和 横纹肌肉瘤的耐药性(目标2)。 我已经确定米特拉霉素是一种SWI/SNF抑制剂，可以诱导表观遗传重新编程和持久肿瘤 横纹肌样瘤消退。米曲霉素治疗的结果是H3K27me3的扩增，一种新的 治疗的脆弱性以及化疗敏感性的恢复。F99阶段的总体目标(AIM 1)鉴定由SWI/SNF抑制引起的合成致死性。具体地说，Aim 1.1将定义抑制 H3K27me3组蛋白去甲基酶KDM6A/6B在横纹肌样瘤治疗中的易感性。AIM 1.2将 明确米曲霉素依赖化疗敏感性的机制。这些目标将建立先进的专业知识 在机制药理学、高通量测序和联合疗法的体内建模方面。在……里面 与已知的化疗耐药的RT不同，泡状横纹肌肉瘤最初对 在获得抗药性之前进行化疗。因此，该奖学金的K00阶段(目标2)将定义 染色质重构在融合阳性泡状横纹肌肉瘤治疗抵抗中的作用。 AIM 2.1将确定与致癌的PAX3/7-FOXO1协调的染色质重构体 驱动手臂转化和进展的转录因子。AIM 2.2将描述染色质重塑 在已建立的小鼠化疗耐药模型建立过程中。这一阶段将扩大 在基因组学方法方面的专业知识，包括单细胞基因组学和体内建模，包括转基因 模特们。 总之，这项研究解决了对染色质的作用进行机械性研究的必要性 重塑在推动儿童实体肿瘤治疗反应中的作用。在这一阶段获得的数据和培训 将为我的职业生涯做好准备，探索儿童肉瘤治疗耐药的表观遗传机制。

PROJECT SUMMARY Despite the known roles of chromatin remodeling complexes in driving more than 20% of human cancer, the role of chromatin remodeling complexes in conferring therapeutic response in pediatric solid tumors is much less understood. Rhabdoid tumor requires residual SWI/SNF activity for transformation and progression. However, it is not known if SWI/SNF and its effect on the underlying epigenome is therapeutically targetable and if a compound targeting this complex will be successful. Furthermore, SWI/SNF has been implicated in epigenetic mechanisms of resistance suggesting this complex may be able to both confer sensitivity and resistance depending on the cancer context. Fusion positive alveolar rhabdomyosarcoma (ARMS) gains chemo-resistance without the simultaneous gain of mutations to drive this resistance. These data indicate ARMS relapse may be driven by epigenetic mechanisms. Therefore, the overall objective of this study is to define the role of chromatin structure in conferring therapeutic sensitivity in rhabdoid tumor (Aim 1) and resistance in rhabdomyosarcoma (Aim 2). I have identified mithramycin as a SWI/SNF inhibitor that induces epigenetic reprogramming and durable tumor regression in rhabdoid tumor. A consequence of mithramycin treatment is amplification of H3K27me3, a novel therapeutic vulnerability as well as the restoration of chemosensitivity. The overall goal of the F99 phase (Aim 1) is to identify synthetic lethalities that arise from SWI/SNF inhibition. Specifically, aim 1.1 will define inhibition of H3K27me3 histone demethylases KDM6A/6B as a therapeutic vulnerability in rhabdoid tumor. Aim 1.2 will define the mechanism of mithramycin-dependent chemosensitivity. These goals will build advanced expertise in mechanistic pharmacology, high-throughput sequencing, and in vivo modeling of combination therapies. In contrast to RT which is known to be chemo-refractory, alveolar rhabdomyosarcoma is initially responsive to chemotherapy before gaining resistance. Therefore, the K00 phase of this fellowship (Aim 2) will define the role of chromatin remodeling in fusion positive alveolar rhabdomyosarcoma therapeutic resistance (ARMS). Aim 2.1 will identify the chromatin remodeler that coordinates with PAX3/7-FOXO1, the oncogenic transcription factor that drives ARMS transformation and progression. Aim 2.2 will profile chromatin remodeling during the establishment of chemoresistance in an established ARMS mouse model. This phase will expand expertise in genomic approaches to include single-cell genomics and in vivo modeling to include transgenic models. In summary, this study addresses the need for a mechanistic investigation into the role of chromatin remodeling in driving therapeutic response in pediatric solid tumors. Data and training acquired in this phase will prepare me for a career exploring epigenetic mechanisms of therapeutic resistance in pediatric sarcomas.