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: 8254841
• 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 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8254841
• 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; 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（申请人提供）：髓母细胞瘤是最常见的儿童脑癌，是一种起源于小脑的原始神经外胚层肿瘤（PNET）。弥散性表型和复发的患者预后特别差。Ptch + / -;p53-/-小鼠髓母细胞瘤模型的特点是具有播散性表型，包含髓母细胞瘤干细胞（MBSC）群体，这些干细胞具有自我更新的能力，表达神经干细胞标记物，并且在移植后具有强大的肿瘤起始能力。该项目的总体目标是揭示成神经管细胞瘤干细胞存活和自我更新维持的重要分子机制。这个项目的目的是测试MBSC具有细胞可塑性的假设，这种可塑性赋予细胞在非生态位环境中生存优势和抵抗分化的能力，以支持肿瘤传播。初步结果表明，骨髓间充质干细胞具有细胞可塑性，能够在血清分化提示下存活和自我更新。为了更广泛地了解参与存活和可塑性的途径，我将首先确定MBSC的基因表达谱和STAT3在MBSC中的作用。LIF信号通路是一种已知的干细胞通路，对它的检测导致在MBSC中观察到异常的STAT3激活。STAT3在MBSC存活和自我更新中的功能作用将通过RNAi和STAT3小分子抑制剂得到验证。初步数据还表明，STAT3及其下游靶点Klf4协同调节生存基因Mcl-1和Bclx的表达。在第二个目标中，将通过STAT3和Klf4的双KD以及具有突变结合位点的生存基因启动子荧光素酶试验来检测STAT3和Klf4在生存基因调控中的合作。最后，通过颅内移植检测STAT3/Klf4通路抑制的治疗价值