The Role of Bcl2L12 in the Genesis of Malignant Glioma

Bcl2L12 在恶性胶质瘤发生中的作用

• 批准号: 7765140
• 负责人: Alexander H. Stegh
• 金额: $ 24.9万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-17 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7765140
• 关键词: Alleles; Anaplastic astrocytoma; Apoptosis; Apoptotic; Astrocytes; Binding; Biochemical; Biological; Brain; Caspase; Cell Culture Techniques; Cells; Cessation of life; Clinical; Complement; Computer Simulation; Coupled; Data; Diagnosis; Disease; Elements; Future; Gene Expression Profile; Gene Targeting; Gene Transfer Techniques; Genes; Genomics; Glioma; Goals; Growth; Human; Inhibition of Apoptosis; Maintenance; Malignant - descriptor; Malignant Glioma; Malignant neoplasm of brain; Mediating; Mitochondria; Modeling; Modification; Molecular; Molecular Analysis; Monitor; Mus; Necrosis; Neurons; Nucleoplasm; Oncogene Proteins; Oncogenic; Outcome; Pathway interactions; Property; Protein p53; Proteins; Resistance; Role; Sampling; Stem cells; Structure; Subgroup; System; TP53 gene; Testing; Therapeutic Intervention; Transactivation; Translations; Transplantation; Validation; base; brain tissue; caspase-3; caspase-7; chromatin immunoprecipitation; genome-wide; in vivo; indexing; inhibitor/antagonist; mutant; neoplastic cell; nerve stem cell; novel; polypeptide; research study; stem; therapeutic target; tumor; tumor growth; tumorigenic

DESCRIPTION (provided by applicant): Glioblastoma multiforme (GBM), the most aggressive manifestation of malignant gliomas, are characterized by microvascular proliferation, necrosis, extreme resistance to all extant therapeutic modalities and a neurologically destructive course culminating in death often within 12 months of diagnosis. Major conceptual gaps remain on the mechanistic level including how the classical genetic lesions contribute to these phenotypic aspects. To address this issue, we performed oncogenomic analyses of a large panel of human GBMs by array-CGH and expression profiling in an effort to gain a more comprehensive view of the genetic events underlying GBM development. In the course of characterizing a region of gain on chromosome 19q, we identified Bcl2L12 (for Bcl2-Like-12) as a glioma oncogene that is over-expressed in virtually all GBM samples, yet low or absent in low-grade disease and normal tissue. Extensive biochemical studies have established that Bcl2L12 functions as an anti-apoptotic protein in primary astrocytic cultures by inhibiting post-mitochondrial caspase-3 and caspase-7 activation. Since inhibition of apoptosis at the post- mitochondrial level is known to block apoptosis but promotes necrosis, Bcl2L12 over-expression in GBM may provide a rational explanation for a prime paradox in the biology of this disease - apoptosis resistance yet florid necrosis - and points to Bcl2L12 up-regulation as a key progression event in malignant glioma. In addition to its cytosolic caspase-3/7 inhibitory activity, Bcl2L12 resides in the nucleoplasm where it interacts with p53 and blocks p53-mediated transactivation. To analyze Bcl2L12-modulated pathways in cell culture- based assays in more detail and to genetically validate these findings in vivo, this grant proposal aims to elucidate further the molecular basis of Bcl2L12's oncogenic activity through detailed structure-function analyses. We will employ cell culture-based assays and orthotopic SCID explant tumor models using genetically engineered neuronal stem cells and mature cortical astrocytes to dissect apoptosis- and p53 modulatory activities. Furthermore, we will characterize in depth the molecular mechanism of p53 inhibition that defines yet another oncogenic activity of Bcl2L12 through detailed studies of p53-mediated transcriptional regulation. Finally, the consequences of Bcl2L12 inactivation for the development of GBM will be assessed using conditional Bcl2L12 knockout mice that may serve as an in vivo platform on which to assess consequence of pharmacological inactivation of Bcl2L12 for malignant glioma therapy. The continued lack of success in treating high-grade gliomas has prompted a reevaluation of all aspects of glioma drug development. This grant proposal aims to specifically address the currently unmet needs in the development of effective glioma therapies by refining the molecular understanding of the disease and by developing more accurate in vitro and in vivo glioma model system.

描述（由申请人提供）：多形性胶质母细胞瘤（GBM）是恶性胶质瘤中最具侵袭性的表现，其特征为微血管增生、坏死、对所有现有治疗方式的极端抵抗以及神经学破坏性病程，通常在诊断后12个月内死亡。主要的概念差距仍然在机制层面上，包括如何经典的遗传病变有助于这些表型方面。为了解决这个问题，我们进行了一个大的面板的人类GBM的阵列CGH和表达谱的癌基因组分析，努力获得一个更全面的观点GBM发展的遗传事件。在表征染色体19 q上的增益区域的过程中，我们将Bcl 2L 12（对于Bcl 2样-12）鉴定为胶质瘤癌基因，其在几乎所有GBM样品中过表达，但在低度疾病和正常组织中低表达或不表达。广泛的生物化学研究已经确定Bcl 2L 12通过抑制线粒体后半胱天冬酶-3和半胱天冬酶-7活化在原代星形胶质细胞培养物中作为抗凋亡蛋白发挥作用。由于已知在线粒体后水平上抑制细胞凋亡会阻断细胞凋亡但促进坏死，因此GBM中Bcl 2L 12过表达可为该疾病生物学中的主要矛盾-细胞凋亡抗性但华丽坏死-提供合理解释，并指出Bcl 2L 12上调是恶性胶质瘤中的关键进展事件。除了其胞质半胱天冬酶-3/7抑制活性外，Bcl 2L 12存在于核质中，在那里它与p53相互作用并阻断p53介导的反式激活。为了在基于细胞培养的测定中更详细地分析Bcl 2L 12调节的途径，并在体内遗传学上验证这些发现，该资助提案旨在通过详细的结构-功能分析进一步阐明Bcl 2L 12致癌活性的分子基础。我们将采用细胞培养为基础的分析和原位SCID外植体肿瘤模型，使用基因工程神经干细胞和成熟的皮质星形胶质细胞解剖细胞凋亡和p53的调节活性。此外，我们将深入研究p53抑制的分子机制，通过对p53介导的转录调控的详细研究，确定Bcl 2L 12的另一种致癌活性。最后，将使用条件性Bcl 2L 12敲除小鼠来评估Bcl 2L 12失活对GBM发展的后果，所述条件性Bcl 2L 12敲除小鼠可用作评估Bcl 2L 12药理学失活对恶性胶质瘤治疗的后果的体内平台。 治疗高级别胶质瘤的持续缺乏成功促使重新评估胶质瘤药物开发的各个方面。该拨款提案旨在通过完善对该疾病的分子理解和开发更准确的体外和体内胶质瘤模型系统，专门解决目前在开发有效胶质瘤治疗方面未满足的需求。