Mechanisms underlying USP1-mediated bypass of EWS-FLI1 oncogene-induced replication stress in Ewing sarcoma

USP1介导的EWS-FLI1癌基因诱导的尤文肉瘤复制应激旁路的机制

• 批准号: 10446807
• 负责人: GARGI GHOSAL
• 金额: $ 35.11万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-05 至 2027-07-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10446807
• 关键词: Apoptosis; Basic Science; Bypass; Cell Aging; Cell Cycle; Cell Cycle Arrest; Cell Cycle Progression; Cell Death; Cell Line; Cell Maintenance; Cell Proliferation; Cell physiology; Cells; ChIP-seq; Childhood; Chromosomal translocation; Chromosome 11; Chromosome 22; DNA; DNA Damage; DNA Repair; DNA biosynthesis; DNA-protein crosslink; Data; Deubiquitination; Development; Disease Progression; E2F transcription factors; EWSR1 gene; Epigenetic Process; Ewings sarcoma; FLI1 gene; Family; Fiber; Gene Expression; Gene Fusion; Generations; Genes; Genetic Transcription; Genome; Genome Stability; Genomic Instability; Growth; HELLS gene; Histones; In Vitro; Lysine; Malignant Bone Neoplasm; Maps; Mediating; Mesenchymal Stem Cells; Molecular; Normal Cell; Oncogenes; Oncogenic; Pathogenesis; Pathway interactions; Patients; Pharmaceutical Preparations; Phenocopy; Proteins; Regulation; Role; S phase; Site; Testing; Treatment Efficacy; Ubiquitin; Ubiquitination; Xenograft Model; base; biological adaptation to stress; bone; cancer cell; cell growth; chemotherapy; chromatin remodeling; comparative; epigenetic regulation; genome wide methylation; genome-wide analysis; improved; in vivo; inhibitor; insight; knock-down; methylation pattern; mutant; new therapeutic target; novel; overexpression; repaired; replication stress; response; sarcoma; small molecule; standard of care; stem cells; t(11; 22)(q24; q12); targeted treatment; transcription factor; transcriptome sequencing; treatment strategy; tumor; tumor growth; tumorigenesis; ubiquitin-protein ligase; ubiquitin-specific protease

PROJECT SUMMARY Replication stress leading to genome instability is an early driver of tumorigenesis and has been associated with overexpression of oncogenes. In normal cells, activation of the DNA damage response (DDR) pathway serves as a barrier to tumorigenesis leading to cell cycle arrest inducing cellular senescence or cell death in response to high burden of genome instability. However, in cancer cells upon oncogene-induced replication stress the protective barrier of DDR, cell death and senescence is bypassed leading to uncontrolled cell proliferation. Therefore, deciphering the mechanisms that bypass oncogene-induced replication stress and senescence will help understand the basic science underlying disease progression and will identify new targets for therapy. Ewing sarcoma (EWS) is driven by a chromosomal translocation and in-frame gene fusion between EWSR1 and ETS family of transcription factors. In majority of the EWS cases, the chromosomal translocation results in the generation of EWS-FLI1 oncogene. EWS-FLI1 functions as an aberrant transcription factor that drives the development and progression of EWS. Expression of EWS-FLI1 oncogene leads to oncogene-induced replication stress and genome instability. However, the molecular mechanism underlying bypass of EWS-FLI1 oncogene-induced replication stress response pathways is largely unknown. Our preliminary data shows that USP1 deubiquitinase is overexpressed in EWS cell lines and tumors. USP1 regulates DDR and is required for genome stability and stem cell maintenance. We find that USP1 expression is regulated by EWS-FLI1 in EWS. Importantly, inhibition of USP1 activity using small molecule USP1 inhibitors resulted in growth arrest of EWS cell lines indicating that USP1 expression and activity is important for EWS cell proliferation and progression. Notably, USP1 depletion led to a decrease in the levels of HELLS chromatin remodeling protein. The function of USP1 or HELLS in EWS pathogenesis has not been investigated. In this study, we will examine the regulation of HELLS by USP1 deubiquitinase (Aim 1), determine the mechanism by which USP1 promotes EWS cell proliferation (Aim 2), and determine the effect of USP1 knockdown on EWS tumor formation in vivo and the efficacy of USP1 inhibition in combination with chemotherapeutic drugs at suppressing EWS cell proliferation (Aim 3). Successful completion of this study will unravel novel mechanistic insights into USP1 mediated bypass of EWS-FLI1 oncogene-induced replication stress and help evaluate USP1 targeted treatment strategies for EWS.

项目摘要 导致基因组不稳定性的复制应力是肿瘤发生的早期驱动力，已经是 与癌基因的过表达有关。在正常细胞中，激活DNA损伤反应（DDR） 途径是肿瘤发生的障碍，导致细胞周期停滞诱导细胞衰老或细胞 响应基因组不稳定负担的高负担而死亡。但是，在癌细胞中，癌细胞诱导的 复制压力DDR，细胞死亡和衰老的保护屏障被绕过导致不受控制的 细胞增殖。因此，解密绕过癌基因诱导的复制应力和的机制 衰老将有助于了解基础科学的基础疾病进步，并将确定新目标 用于治疗。 尤因肉瘤（EWS）是由染色体易位和框内基因融合驱动的 EWSR1和ETS转录因子家族。在大多数EWS情况下，染色体易位 导致EWS-FLI1癌基因产生。 EWS-FLI1充当异常转录因子 推动EWS的发展和发展。 EWS-FLI1致癌基因的表达导致癌基因诱导 复制应力和基因组不稳定性。但是，EWS-FLI1旁路的分子机制 致癌基因诱导的复制应力响应途径在很大程度上未知。我们的初步数据表明 USP1去泛素酶在EWS细胞系和肿瘤中过表达。 USP1调节DDR，并且需要 基因组稳定性和干细胞维持。我们发现USP1表达受EWS中的EWS-FLI1调节。 重要的是，使用小分子USP1抑制剂抑制USP1活性导致EWS的生长停滞 细胞系表明USP1表达和活性对于EWS细胞增殖和进展很重要。 值得注意的是，USP1耗竭导致地狱染色质重塑蛋白的水平降低。功能 尚未研究EWS发病机理中的USP1或地狱。在这项研究中，我们将检查法规 USP1去泛素酶（AIM 1）的地狱，确定USP1促进EWS细胞的机制 增殖（AIM 2），并确定USP1敲低对体内EWS肿瘤形成的影响 USP1抑制与化学治疗药物在抑制EWS细胞增殖时的功效 （目标3）。 这项研究的成功完成将揭开对USP1介导的旁路的新机械见解 EWS-FLI1致癌基因引起的复制应力，并有助于评估USP1的目标治疗策略 EWS。