Reprogramming myogenic regulatory factors in RMS to promote differentiation and halt growth

重新编程 RMS 中的生肌调节因子以促进分化并阻止生长

• 批准号: 10682281
• 负责人: Kristin Artinger
• 金额: $ 67.27万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-16 至 2028-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10682281
• 关键词: ATAC-seq; Adult; Animal Model; Animals; Automobile Driving; Binding; Biological Assay; Biological Models; Cancer Patient; Cell Differentiation process; Cells; Chemoresistance; Child; Childhood; Chromatin; Complement; Coupling; DNA Binding; Data; Development; Developmental Gene; Diagnosis; Disease; Drug Targeting; Embryo; Embryonal Rhabdomyosarcoma; Embryonic Development; Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor; Generations; Genes; Genetic; Genome engineering; Genomics; Growth; Human; Individual; Invaded; Knock-out; Knowledge; Lead; Life; Maintenance; Malignant Childhood Neoplasm; Malignant Neoplasms; Mass Spectrum Analysis; Mesoderm Cell; Mission; Modeling; Molecular; Morbidity - disease rate; Mus; Muscle; Muscle Development; Muscle satellite cell; Myoblasts; Myogenic Regulatory Factors; Neoplasm Metastasis; Normal Cell; Patients; Pediatric Neoplasm; Pediatric Oncology; Persons; Phenotype; Physicians; Play; Proliferating; Proteins; Public Health; Research; Rhabdomyosarcoma; Role; Scientific Advances and Accomplishments; Scientist; Soft Tissue Neoplasms; Survival Rate; System; Techniques; Testing; Tissue Differentiation; Tissues; Toxic effect; Treatment-related toxicity; Tumor stage; Undifferentiated; Work; Xenograft procedure; Zebrafish; cancer cell; childhood cancer survivor; chromosome fusion; cofactor; design; epigenomics; experience; experimental study; gain of function; genome-wide; human model; insight; knock-down; knockout gene; malignant phenotype; migration; mortality; new therapeutic target; novel; novel therapeutic intervention; novel therapeutics; overexpression; pharmacologic; pre-clinical; precursor cell; progenitor; programs; sarcoma; side effect; small molecule inhibitor; stem; stem cells; targeted treatment; therapeutic development; tool; transcription factor; transcriptomics; treatment strategy; tumor; tumor growth; tumor progression

Summary Rhabdomyosarcoma (RMS) accounts for 3-4% of all pediatric cancers, with less than a 30% overall 5-year survival rate for children diagnosed with metastatic RMS. Sarcoma patients also experience higher rates of morbidity and mortality than other cancer patients, and this is particularly evident in children. As a result of their therapies, 42% of childhood cancer survivors experience severe, disabling, or life threatening conditions, including secondary tumors. Thus, there is clearly a need to develop new, more targeted treatment strategies for pediatric tumors such as RMS; treatments that inhibit tumor progression yet confer limited side effects. In many cancers, embryonic programs, including the acquisition of stem/progenitor states, are instituted to contribute to tumor progression. Such reinstatement or retention of developmental programs may be a key driving factor in Embryonal Rhabdomyosarcoma (ERMS, which are generally fusion negative and also referred to as FN-RMS). In RMS, high expression of myogenic-lineage transcription factors (TF), MYOD1 and MYOG, is observed. However, despite high expression of these TFs, RMS cells fail to differentiate. Instead, these TFs drive the RMS malignant phenotype, since knockout of these MRFs results in lethality to the RMS cell. Thus, a key unanswered question in the field is why and how the myogenic regulatory factors (MRFs) depart from their canonical roles as drivers of muscle differentiation to instead maintain RMS cells in an undifferentiated state. In this proposal, we are examining whether SIX1, a critical TF that regulates muscle development, is responsible for globally altering the function of MRFs. Our data show that elevated SIX1 expression promotes FN-RMS progression and growth by promoting an RMS progenitor-like state. Intriguingly, SIX1 knockdown induces a muscle differentiation signature, concomitant with re-localization of key MRFs genome-wide. These data suggest that in FN-RMS, SIX1 overexpression alters MRF function, promoting an RMS progenitor-like phenotype and enhancing tumor growth and progression. Thus, in this proposal we will test the following hypothesis: SIX1 and its obligate cofactors EYA2/3 cooperatively drive the progression of FN-RMS by altering the genomic landscape, causing MRFs to favor growth over differentiation. Since SIX1 expression in differentiated tissues is low, targeting it may therefore be a means to inhibit FN-RMS with limited side effects to untransformed cells where SIX1 is dispensable. Specific aims are as follows: 1) To determine the molecular mechanism by which SIX1 serves as a master regulator of the muscle progenitor vs differentiated state in development and in RMS. 2) To identify the critical SIX1 cofactors (with a focus on EYA proteins) that, when targeted, can induce differentiation and inhibit RMS growth. This work will take advantage of normal developmental regulatory mechanisms to inhibit the tumor, and thus may have limited toxicity due to the paucity of SIX/EYA expression in adult tissue. Our ability to combine zebrafish and human models will maximize the benefits of each model system to rapidly and inexpensively identify means to inhibit RMS growth and progression. Understanding the mechanisms by which RMS cells are trapped in an early developmental state may therefore lead to novel means to target the disease.

概括 横纹肌肉瘤（RMS）占所有儿科癌症的3-4％，总5年生存率不到30％ 诊断为转移性RMS的儿童的率。肉瘤患者还经历了更高的发病率和 死亡率比其他癌症患者，这在儿童中尤其明显。由于他们的疗法，有42％ 儿童期癌症幸存者经历严重，残疾或威胁生命的条件，包括次要 肿瘤。因此，显然需要为小儿肿瘤制定新的，更具针对性的治疗策略 例如RMS；抑制肿瘤进展但赋予有限副作用的治疗方法。在许多癌症中， 建立了胚胎程序，包括恢复STEM/祖细胞状态，为肿瘤做出贡献 进展。这种恢复或保留发展计划可能是关键的驱动因素 胚胎横纹肌肉瘤（ERMS，通常为融合为阴性，也称为FN-RMS）。 在RMS中，观察到了肌原分的转录因子（TF），Myod1和Myog的高表达。 但是，尽管这些TF表达很高，但RMS细胞仍无法区分。相反，这些TF驱动RMS 恶性表型，因为这些MRF的敲除导致RMS细胞的致死性。因此，一个钥匙未回答 该领域的问题是为什么以及肌源性调节因素（MRF）如何偏离其规范角色 肌肉分化的驱动因素将RMS细胞保持在未分化状态。在这个建议中，我们 正在研究调节肌肉发育的关键TF SIX1是否负责全球变化 MRF的功能。我们的数据表明，升高的SIX1表达促进FN-RMS的进展和生长 通过促进RMS祖细胞状状态。有趣的是，Six1敲低诱导肌肉差异化 签名，与关键MRF基因组重新定位。这些数据表明，在FN-RMS中，Six1 过表达改变了MRF功能，促进RMS祖细胞样表型并增强肿瘤生长 和进展。因此，在此提案中，我们将检验以下假设：SIX1及其强制性辅助因子 EYA2/3通过改变基因组景观，合作驱动FN-RMS的进展，导致MRFS 有利于增长而不是分化。由于分化组织中的六1表达较低，因此可能 因此，是抑制对未转换细胞有限副作用的FN-RMS的一种手段 可分配。具体目的如下：1）确定六1的分子机制 肌肉祖细胞的主要调节剂与开发和RMS中的差异化状态。 2）确定 关键的六1个辅因子（重点是EYA蛋白），当针对目标时，可以诱导分化并抑制 RMS增长。这项工作将利用正常的发育调节机制来抑制肿瘤， 因此，由于成人组织中六/eya表达的缺乏，毒性可能有限。我们结合的能力 斑马鱼和人类模型将最大化每个模型系统的好处 确定抑制RMS生长和进展的方法。了解RMS细胞的机制 因此，被困在早期发育状态可能会导致靶向这种疾病的新型手段。