Cellular plasticity and survival mechanisms in medulloblastoma stem cells

髓母细胞瘤干细胞的细胞可塑性和生存机制

• 批准号: 8549694
• 负责人: RONNIE YOO
• 金额: $ 2.95万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-03-01 至 2013-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8549694
• 关键词: Address; Binding Sites; Biological Assay; Brain Neoplasms; Cancer Patient; Cell Maintenance; Cell Survival; Cells; Cerebellum; Childhood; Collaborations; Conditioned Culture Media; Cues; Data; Disease; Down-Regulation; Environment; Exhibits; Gene Expression; Gene Expression Profile; Gene Expression Regulation; Genes; Goals; Human; In Vitro; LIF gene; Laboratories; Lead; Luciferases; Maintenance; Malignant neoplasm of brain; Molecular; Neoplasm Metastasis; Pathway interactions; Patients; Phenotype; Play; Population; Primitive Neuroectodermal Tumor; Property; RNA Interference; Radioresistance; Recurrence; Regulation; Relapse; Research; Research Proposals; Resistance; Role; STAT3 gene; Serum; Signal Transduction; Stem cell transplant; Stem cells; Testing; Therapeutic; Transplantation; Tumor Stem Cells; Work; base; cancer stem cell; in vivo; inhibitor/antagonist; insight; irradiation; medulloblastoma; mouse model; mutant; nerve stem cell; novel; outcome forecast; promoter; relating to nervous system; research study; self-renewal; small molecule; stem cell niche; therapeutic target; transcription factor; tumor; tumor initiation

DESCRIPTION (provided by applicant): Medulloblastoma, the most common pediatric brain cancer, is a primitive neuroectodermal tumor (PNET) that arises in the cerebella. Patients with a disseminated phenotype and relapse have particularly poor prognoses. The Ptch+/-;p53-/- mouse model of medulloblastoma have been characterized as having a disseminated phenotype and contain a population of medulloblastoma stem cell (MBSC), which have the ability for self-renewal, expression of neural stem cells markers and potent tumor-initiation upon transplantation. The overall goal of this project is to undercover new molecular mechanisms that are important for the survival and maintenance of self-renewal in the medulloblastoma stem cells. This aims in this project will the test the hypothesis that the MBSC have a cellular plasticity that confers the cells a survival advantage and resistance to differentiation in non-niche environments, to support tumor dissemination. Preliminary results showed that the MBSC exhibit a cellular plasticity allowing them to survive and self-renew in the presence of the differentiation cues of serum. To gain a broader understanding of the pathways involved in the survival and plasticity, I will first determine the gene expression profile of the MBSC and the rol of STAT3 in the MBSC. Examination of LIF signaling, a known stem cell pathway, has led to the observation of aberrant STAT3 activation in the MBSC. The functional role of STAT3 in MBSC survival and self-renewal will be validated by RNAi and STAT3 small molecule inhibitors. Preliminary data also suggest that STAT3 and its downstream target Klf4, are collaboratively regulating the expression of survival genes Mcl-1 and Bclx. In the second aim, the cooperation of STAT3 and Klf4 in survival gene regulation will be tested by double KD of STAT3 and Klf4, as well as survival gene promoter-luciferase assays with mutant binding sites. Lastly, the therapeutic value of STAT3/Klf4 pathway inhibition will be tested with intracranial transplantation assays and to determine if a synergistic effect on MBSC elimination is observed with combination treatment with irradiation therapy and STAT3/Klf4 inhibition. Completion of the research proposal will provide insights into the cooperative role of STAT3 and Klf4 in MBSC survival and address the potential of STAT3/Klf4 inhibition as a therapeutic target for disseminated human medulloblastomas.

描述（由申请人提供）：髓母细胞瘤是最常见的儿科脑癌，是一种起源于小脑的原始神经外胚层肿瘤（PNET）。具有播散性表型和复发的患者具有特别差的预后。Ptch+/-;成神经管细胞瘤的p53-/-小鼠模型已被表征为具有播散性表型并含有成神经管细胞瘤干细胞（MBSC）群体，其具有自我更新、表达神经干细胞标志物和在移植后有效的肿瘤起始的能力。本项目的总体目标是揭示对髓母细胞瘤干细胞的生存和自我更新的维持至关重要的新分子机制。该项目的目的是检验MBSC具有细胞可塑性的假设，该细胞可塑性赋予细胞在非生态位环境中的生存优势和抗分化能力，以支持肿瘤扩散。初步结果表明，MBSC表现出细胞可塑性，使他们能够生存和自我更新的血清分化线索的存在下。为了更广泛地了解参与生存和可塑性的途径，我将首先确定MBSC的基因表达谱和STAT 3在MBSC中的作用。对LIF信号传导（一种已知的干细胞通路）的检查导致在MBSC中观察到异常的STAT 3活化。STAT 3在MBSC存活和自我更新中的功能作用将通过RNAi和STAT 3小分子抑制剂来验证。初步数据还表明，STAT 3及其下游靶标Klf 4协同调节存活基因Mcl-1和Bclx的表达。在第二个目标中，STAT 3和Klf 4在存活基因调节中的合作将通过STAT 3和Klf 4的双KD以及具有突变结合位点的存活基因启动子-荧光素酶测定来测试。最后，将通过颅内移植来测试STAT 3/Klf 4通路抑制的治疗价值 本发明的目的是通过放射治疗和STAT 3/Klf 4抑制的组合治疗来测定MBSC的清除，并确定是否观察到对MBSC清除的协同作用。该研究提案的完成将为STAT 3和Klf 4在MBSC存活中的合作作用提供见解，并解决STAT 3/Klf 4抑制作为播散性人髓母细胞瘤治疗靶点的潜力。