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.

迫切需要开发新的方法来靶向致癌转录因子。尤因 肉瘤（ES）象征着这种需求。 ES绝对是25年以上 取决于细胞存活的EWS-FLI1转录因子。 EWS-FLI1是唯一的复发突变 ES（> 20％的肿瘤）和细胞对该蛋白的依赖性已通过多个 独立研究。我们的总体目标是识别和临床翻译，以抑制EWS- FLI1可改善Ewing肉瘤患者的预后。与这个目标一致，我们已经确定了 小凹槽DNA结合化合物TraceDIN作为EWS-FLI1的抑制剂。我们已经移动了这个 与低剂量伊立替康结合使用的化合物进入诊所，并看到了惊人的临床反应。 但是，一些患者在接受治疗时进展。其他患者需要减少剂量 限制治疗效率的毒性。因此，在这项研究中，我们提出了更深入的理解 活性和耐药性机制将改善治疗。我们假设这些 通过我们定义的机制，可以改变染色质结构和 细胞状态的方式使细胞恢复。更确切地说，我们已经证明了这是追踪的 将核中的EWS-FLI1重新分布到核仁中，以触发表观遗传开关以改变染色质 EWS-FLI1驱动的GGAA微卫星增强剂的可访问性。但是，我们在这里提出了其他 表观遗传学DNA损伤反应机制，通过公正的方法识别，留下染色质 被毒死了。此外，我们已经表明，将EWS-FLI1重新分布到Nucleolus可以稳定 因此，融合蛋白提供了一个有助于转录恢复的储备池。因此，目标的目标 研究是直接针对这些中毒状态，以改善化合物的活性，限制毒性并限制 电阻机制。重要的是，这些方法应该改善毒性特征，因为它们 专注于仅在Ewing肉瘤细胞及其下游GGAA微卫星中发现的EWS-FLI1 在正常细胞中没有已知功能的增强子。如果成功，这项研究将产生小说 机械集中的联合疗法针对后继的尤因肉瘤患者将建立在 追踪素/伊立替康的初步成功。此外，该研究将为使用的重要见解 DNA结合化合物作为致癌转录因子的抑制剂。最后，它将产生一个小说的“陷阱” 目标相变转录因子的方法。