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.

抽象的 髓母细胞瘤是最常见的恶性儿童脑肿瘤，其中大量占所有 儿童癌症死亡。 MB是非常快速增长的肿瘤，它扩散到中枢神经系统（CNS） 通过脑脊液的脑脊液，导致脑膜转移，在脑癌中最多发生66％ 患者。尽管治疗MB方面取得了进展，但高风险MB的5年生存率仍然很差 复发。此外，由于较高的生存孩子的生活质量大大降低了 与高辐射暴露和多种药物化学疗法相关的毒性，它们必须在这种情况下忍受 很小的时候。因此，确定新因素并理解先前未定义的机制至关重要 这种推动了MB的生长和进展，因此可以开发出可用于治疗MB的安全疗法。在 该提案，我们提供了令人信服的证据，表明RNA脱甲基酶Alkbh5可能在MB中起重要作用 通过支持MB癌（肿瘤引发）干细胞（MB-CSC）的生长和进展，从而充当 新颖的治疗靶标。我们的初步结果表明，MB细胞高度依赖于ALKBH5 生存。使用有或没有ALKBH5耗竭的多个MB细胞系，我们发现AlkBH5的耗竭 抑制了MB细胞的短期和长期生长。此外，AlkbH5的耗竭抑制了迁移 MB细胞。重要的是，我们表明ALKBH5沉默抑制了MB茎的自我更新/增殖 细胞。支持这一点，ALKBH5止血导致癌症干细胞标记水平显着降低。这些 是重要的发现，因为MB干细胞被认为是MB启动，维持，， 复发和渲染MB细胞对辐射的抗性。这些观察结果使我们假设RNA 脱甲基酶AlkBH5通过促进癌症干细胞自我更新来支持MB的生长和进展。和 旨在靶向ALKBH5水平/活性的方法将使MB患者的辐射反应敏感。到 检验这些假设，我们提出以下两个具体目的：在AIM＃1中，确定AlkBH5作为一个 MB生长和进展的启动子。在AIM＃2中，确定ALKBH5调节的机制 通过识别和表征ALKBH5靶基因及其在MB中的M6A状态，MB的干和生长 细胞。该提案的成功完成将表明RNA表观遗传学作为重要的调节剂 髓母细胞瘤干细胞活力和自我更新。据报道Alkbh5敲除小鼠可行 我们的初步研究表明，MB细胞存活对ALKBH5的依赖性很高，这表明ALKBH5可以 作为治疗MB患者的新型且安全的治疗靶标。