Targeting the RNA modifying enzyme ALKBH5 in Medulloblastoma

靶向髓母细胞瘤中的 RNA 修饰酶 ALKBH5

• 批准号: 10747017
• 负责人: Panneerdoss Subbarayalu
• 金额: $ 18.12万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 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 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10747017
• 关键词: Address; Age; Animal Model; Binding Proteins; Biochemical; Biological Assay; Brain Neoplasms; Cancer Patient; Carbohydrates; Cell Line; Cell Proliferation; Cell Survival; Cell model; Cells; Central Nervous System; Cerebrospinal Fluid; Cessation of life; Child; Childhood Malignant Brain Tumor; Clinical; Dependence; Elements; Energy Metabolism; Enzymes; Epigenetic Process; Genes; Growth; Knockout Mice; Leptomeninges; Maintenance; Malignant Childhood Neoplasm; Malignant Neoplasms; Malignant neoplasm of brain; Malignant neoplasm of liver; Metabolic; Metastatic Neoplasm to the Leptomeninges; Modeling; Patients; Pediatric Neoplasm; Pharmaceutical Preparations; Play; Positioning Attribute; Proliferating; Proto-Oncogene Proteins c-myc; Quality of life; RNA; Radiation; Radiation exposure; Radiosensitization; Recurrence; Relapse; Reporting; Resistance; Role; Signal Transduction; Source; Spinal; Survival Rate; Testing; Therapeutic; Toxic effect; Vertebral column; Vincristine; Xenograft Model; aerobic glycolysis; c-myc Genes; cancer stem cell; chemotherapy; childhood cancer mortality; conventional therapy; experience; experimental study; gain of function; high risk; in vivo Model; knock-down; lipid biosynthesis; loss of function; medulloblastoma; medulloblastoma cell line; migration; neoplastic cell; new therapeutic target; novel; patient derived xenograft model; programs; promoter; radiation resistance; radiation response; radioresistant; response; self-renewal; side effect; stem cell biomarkers; stem cell proliferation; stem cell self renewal; stem cell survival; stem cells; stemness; therapeutic target; treatment response; tumor; tumor initiation; tumor xenograft

Abstract Medulloblastoma is the most common malignant childhood brain tumor, which accounts for large number of all childhood cancer deaths. MB are very fast-growing tumors, which spreads to central nervous system (CNS) through cerebrospinal fluid, which leads to leptomeningeal metastases that occurs up to 66% in brain cancer patients. Despite the progress in treating MB, the 5-year survival rate for high-risk MB remains poor with high recurrence. Moreover, the quality of life for those kids who do survive is substantially reduced due to the high toxicity associated with the high radiation exposure and multiple drug chemotherapy they must endure at such an early age. Therefore, it is critical to identify novel factors and understand previously undefined mechanisms that drive MB growth and progression, so that safe and viable therapeutics can be developed for treating MB. In this proposal, we provide compelling evidence that RNA demethylase ALKBH5 may play an important role in MB growth and progression by supporting MB cancer (tumor initiating) stem cells (MB-CSC) and thus serve as a novel therapeutic target. Our preliminary results revealed that MB cells are highly dependent on ALKBH5 for its survival. Using multiple MB cell lines with or without ALKBH5 depletion, we discovered that depletion of ALKBH5 inhibited both short and long-term growth of MB cells. In addition, depletion of ALKBH5 inhibited the migration of MB cells. Importantly, we show that ALKBH5 silencing suppressed the self-renewal/proliferation of MB stem cell. Supporting that, ALKBH5-depletion led to significantly decreased levels of cancer stem cell markers. These are significant findings as MB stem cells are considered to be the major source of MB initiation, maintenance, relapse and render MB cells resistant to radiation. These observations led us to hypothesize that RNA demethylase ALKBH5 supports MB growth and progression by promoting cancer stem cell self-renewal; and those approaches aimed at targeting ALKBH5 level/activity will sensitize radiation response in MB patients. To test these hypotheses, we propose following two Specific Aims: In aim#1, To establish the role of ALKBH5 as a promoter of MB growth and progression. In aim#2, To determine the mechanism by which ALKBH5 regulates MB stemness and growth by identifying and characterizing ALKBH5 target genes and their m6A status in MB cells. Successful completion of this proposal will indicate RNA epigenetics as an important regulator of medulloblastoma stem cell viability and self-renewal. Given that ALKBH5 knockout mice is reported to be viable and our preliminary studies showing high dependency of MB cell survival on ALKBH5 suggest that ALKBH5 may serve as a novel and safe therapeutic target for treating MB patients.

摘要 髓母细胞瘤是儿童最常见的恶性脑肿瘤， 儿童癌症死亡。MB是生长非常快的肿瘤，可扩散至中枢神经系统（CNS） 通过脑脊液，导致脑膜转移，脑癌发生率高达66% 患者尽管在治疗MB方面取得了进展，但高危MB的5年生存率仍然很低， 复发此外，那些幸存下来的孩子的生活质量由于高风险而大大降低。 与高辐射暴露和多种药物化疗相关的毒性，他们必须忍受这种 从小就因此，识别新的因素并了解以前未定义的机制至关重要 其驱动MB生长和进展，从而可以开发用于治疗MB的安全和可行的治疗剂。在 这一提议，我们提供了令人信服的证据，RNA去甲基化酶ALKBH 5可能在MB中发挥重要作用。 通过支持MB癌症（肿瘤起始）干细胞（MB-CSC）的生长和进展，从而作为 新的治疗靶点。我们的初步结果显示MB细胞高度依赖ALKBH 5， 生存使用ALKBH 5缺失或未缺失的多个MB细胞系，我们发现ALKBH 5缺失 抑制MB细胞的短期和长期生长。此外，ALKBH 5的耗竭抑制了细胞的迁移。 MB细胞。重要的是，我们发现ALKBH 5沉默抑制MB干细胞的自我更新/增殖。 cell.支持这一点的是，ALKBH 5耗竭导致癌症干细胞标志物水平显著降低。这些 是重要的发现，因为MB干细胞被认为是MB起始，维持， 复发并使MB细胞对辐射具有抗性。这些观察使我们假设RNA 脱甲基酶ALKBH 5通过促进癌症干细胞自我更新来支持MB生长和进展;以及 这些旨在靶向ALKBH 5水平/活性的方法将使MB患者的放射反应敏感。到 为了验证这些假设，我们提出了以下两个具体目标：在aim#1中，为了确定ALKBH 5作为一种细胞因子的作用， MB生长和进展的促进剂。目的#2，确定ALKBH 5调节 通过鉴定和表征MB中的ALKBH 5靶基因及其m6 A状态来确定MB的干性和生长 细胞这项提案的成功完成将表明RNA表观遗传学作为一个重要的调节器， 髓母细胞瘤干细胞活力和自我更新。鉴于ALKBH 5敲除小鼠据报道是可行的， 我们的初步研究显示MB细胞存活对ALKBH 5的高度依赖性，这表明ALKBH 5可能 作为治疗MB患者的新的和安全的治疗靶点。