The interface of transcription, DNA damage and epigenetics: A therapeutic vulnerability of the EWS-FLI1 transcription factor

转录、DNA 损伤和表观遗传学的界面：EWS-FLI1 转录因子的治疗脆弱性

• 批准号: 10718793
• 负责人: Patrick J Grohar
• 金额: $ 50.57万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-06-01 至 2028-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10718793
• 关键词: Binding; Biological Assay; Biology; Cell Nucleolus; Cell Nucleus; Cell Proliferation; Cell Survival; Cells; Chimeric Proteins; Chromatin; Chromatin Structure; Clinic; Clinical; Clinical Data; Clinical Trials; Combined Modality Therapy; Cytoprotection; DNA; DNA Binding; DNA Binding Agent; DNA Damage; DNA Minor Groove Binding; Data; Dependence; Development; Disease; Dose; Doxorubicin; Drug resistance; EWS-FLI1 fusion protein; EWSR1 gene; Enhancers; Epigenetic Process; Etoposide; Ewings sarcoma; FLI1 Transcription Factor; Genes; Genetic Transcription; Genome; Goals; Heat-Shock Proteins 70; Impairment; Malignant Neoplasms; Microsatellite Repeats; Modeling; Mutation; Normal Cell; Nucleotides; Oncogenes; Oncogenic; Output; Patient-Focused Outcomes; Patients; Pharmaceutical Preparations; Phase Transition; Poison; Proteins; Proteomics; Recovery; Recurrence; Relapse; Reporting; Response Elements; Site; Testing; Therapeutic; Toxic effect; Translating; Treatment Efficacy; Ultraviolet Rays; actinomycin; cell type; driver mutation; effective therapy; epigenetic silencing; global run on sequencing; improved; improved outcome; in vivo; inhibitor; insight; irinotecan; novel; novel strategies; patient derived xenograft model; pre-clinical; recruit; research clinical testing; resistance mechanism; response; success; targeted agent; targeted treatment; transcription factor; tumor; tumor growth

There is an urgent need to develop novel approaches to target oncogenic transcription factors. Ewing sarcoma (ES) is emblematic of this need. It has been known for more than 25 years that ES is absolutely dependent on the EWS-FLI1 transcription factor for cell survival. EWS-FLI1 is the only recurrent mutation of ES (>20% of tumors) and the dependence of the cells on this protein has been established by multiple independent studies. Our overarching goal is to identify and clinically translate compounds that inhibit EWS- FLI1 to improve outcomes for patients with Ewing sarcoma. Consistent with this goal, we have identified the minor groove DNA binding compound trabectedin as an inhibitor of EWS-FLI1. We have moved this compound into the clinic in combination with low dose irinotecan and have seen striking clinical responses. However, some patients progress while on therapy. Other patients have required dose reductions due to toxicity that limits the efficacy of the therapy. Therefore, in this study, we propose that a deeper understanding of the mechanisms of activity and drug resistance will improve the therapy. We hypothesize that while these compounds poison EWS-FLI1 by mechanisms that we have defined, they also alter chromatin structure and cellular state in such a way that poises the cell for recovery. More precisely, we have shown that trabectedin redistributes EWS-FLI1 in the nucleus to the nucleolus to trigger an epigenetic switch to alter chromatin accessibility at the EWS-FLI1 driven GGAA microsatellite enhancer. However, here we propose that additional epigenetic DNA damage response mechanisms, identified by unbiased approaches, leaves the chromatin poised for recovery. Additionally, we have shown that redistribution of EWS-FLI1 to the nucleolus stabilizes the fusion protein thus providing a reserve pool that facilitates transcriptional recovery. Therefore, the goal of this study is to directly target these poised states to improve the activity of the compound, limit toxicity, and restrict mechanisms of resistance. Importantly, these approaches should improve the toxicity profile because they focus on EWS-FLI1 which is only found in Ewing sarcoma cells and its downstream GGAA microsatellite enhancer which has no known function in normal cells. If successful, the study will yield a novel mechanistically focused combination therapy for relapsed Ewing sarcoma patients that will build on the preliminary success of trabectedin/irinotecan. In addition, the study will provide important insight into the use of DNA binding compounds as inhibitors of oncogenic transcription factors. Finally, it will yield a novel “trapping” approach to target phase transitioned transcription factors.

迫切需要开发针对尤文致癌转录因子的新方法。 肉瘤 (ES) 是这种需求的象征，25 年来人们就知道 ES 绝对是这种需求。 细胞存活依赖于 EWS-FLI1 转录因子，EWS-FLI1 是唯一的复发突变。 ES（>20% 的肿瘤）和细胞对这种蛋白质的依赖性已被多个研究证实 我们的首要目标是确定并临床转化抑制 EWS- 的化合物。 FLI1 可以改善尤文肉瘤患者的预后，与此目标一致，我们已经确定了 小沟 DNA 结合化合物曲贝替定作为 EWS-FLI1 的抑制剂，我们已将其转移。 该化合物与低剂量伊立替康联合进入临床，并取得了显着的临床反应。 然而，一些患者在治疗期间病情进展，其他患者则因以下原因需要减少剂量。 因此，在这项研究中，我们建议更深入地了解。 活性和耐药性机制的研究将改善治疗。 化合物通过我们定义的机制毒害 EWS-FLI1，它们还会改变染色质结构并 更准确地说，我们已经证明了曲贝替定。 将细胞核中的 EWS-FLI1 重新分配到核仁，以触发表观遗传开关来改变染色质 EWS-FLI1 驱动的 GGAA 微卫星增强器的可访问性但是，我们在这里建议额外的。 通过公正的方法鉴定的表观遗传 DNA 损伤反应机制使染色质留下 此外，我们还发现 EWS-FLI1 重新分布到核仁可以稳定恢复。 融合蛋白从而提供促进转录恢复的储备池。因此，这是其目标。 研究的目的是直接针对这些平衡状态来提高化合物的活性，限制毒性，并限制 重要的是，这些方法应该改善毒性特征，因为它们 关注仅在尤文肉瘤细胞中发现的EWS-FLI1及其下游GGAA微卫星 如果成功，该研究将产生一种新的增强子，该增强子在正常细胞中没有已知的功能。 针对复发尤文肉瘤患者的机械集中联合疗法将建立在 此外，该研究将为曲贝替定/伊立替康的使用提供重要的见解。 DNA结合化合物作为致癌转录因子的抑制剂，最终将产生一种新的“捕获”。 目标相变转录因子的方法。