Precursor cell-niche interactions and the genesis of brainstem gliomas

描述（由申请人提供）：脑干胶质瘤是一种异质性肿瘤，其生物学行为取决于解剖位置。脑干胶质瘤占儿童脑肿瘤的15-20%。其中大多数是脑桥腹侧的弥漫性浸润性胶质瘤，这是一种发生在学龄儿童（高峰在7岁）的毁灭性癌症，几乎总是导致死亡。相反，发生在脑桥背侧、中脑或髓质的胶质瘤通常是惰性的，预后良好。脑桥腹侧胶质瘤（弥漫性内生性脑桥胶质瘤）和背侧胶质瘤之间的这种明显的解剖和病理区分表明，潜在的细胞或微环境过程的失调尚未明确。我假设小儿脑桥腹侧胶质瘤是由出生后前体细胞、微环境生态位或两者的特异性失调引起的。为了支持这一假设，初步研究发现儿童时期人类腹侧脑桥中存在一种新的神经前体细胞群。我们也产生了第一个可用的人类腹侧脑桥胶质瘤细胞培养，并从肿瘤中分离出一种神经干细胞样细胞类型。这代表了该肿瘤研究的重大进展，迄今为止，由于缺乏可用于研究的组织和没有实验模型系统，该研究受到限制。提出的实验计划概述了对正常人和小鼠脑干的干、谱系限制前体细胞和腹背轴胶质细胞群的系统评估，以及对出生后脑干腹背轴信号微环境差异的类似系统检查，并最终测试已确定的候选信号通路和弥漫性固有脑桥胶质瘤细胞中假定的起源细胞的功能意义。使用的技术将包括荧光免疫组织化学和共聚焦显微镜，免疫激光捕获显微解剖，细胞培养，移植研究，FACS，基因表达微阵列分析，单细胞PCR和遗传细胞命运定位。我是一名神经学家，完成了神经科学的博士培训；我的论文项目探讨了出生后海马神经前体细胞命运的微环境决定因素。我目前正在完成神经肿瘤学的研究，并将未来的研究重点放在脑肿瘤病理生理学的产后发育机制上。这项研究计划借鉴了我在出生后干细胞和前体细胞生物学方面的背景，并为我在发育神经科学领域成功过渡到独立所必需的分子生物学技能提供了重要的机会。我的导师Dr. Beachy和联合导师Dr. Rowitch将为我提供一个理想的环境来发展这些技能，并让我沉浸在脑癌发育信号生物学的研究中。我将接受许多分子技术的教学和实践培训，并将获得成功所需的技术和智力支持。

DESCRIPTION (provided by applicant): Brainstem gliomas are a heterogenous group of tumors whose biological behavior depends upon anatomical location. Gliomas of the brainstem comprise 15-20% of brain tumors in children. The majority of these are diffusely infiltrative gliomas of the ventral pons, a devastating cancer that occurs in school age children (peak at age 7) and almost invariably results in death. In dramatic contrast, gliomas occurring in the dorsal pons, midbrain or medulla are classically indolent and carry an excellent prognosis. This sharp anatomic and pathological division between gliomas of the ventral pons (diffuse intrinsic pontine glioma) and those occurring dorsally suggests dysregulation of an underlying cellular or microenvironmental process that is yet to be defined. I hypothesize that pediatric ventral pontine gliomas arise via specific dysregulation of a postnatal precursor cell, microenvironmental niche, or both. In support of this hypothesis, preliminary studies identify a novel population of neural precursor cells in the human ventral pons during childhood. We have also generated the first available cell culture of a human ventral pontine glioma and have isolated from the tumor a neural stem-like cell type. This represents a major advance in the study of this tumor, which has been limited to date by a dearth of tissue available for research and no experimental model system. The proposed experimental plan outlines a systematic evaluation of the normal human and mouse brainstem for stem, lineage-restricted precursor and glial cell populations in the ventral-dorsal axis, as well as a similarly systematic examination of ventral-dorsal differences in the signaling microenvironment of the postnatal brainstem, and finally testing the functional significance of identified candidate signaling pathways and a putative cell of origin in diffuse intrinsic pontine glioma cells. Techniques employed will include fluorescent immunohistochemistry and confocal microscopy, immuno-laser capture microdissection, cell culture, transplantation studies, FACS, gene expression microarray analysis, single cell PCR and genetic cell fate mapping. I am a neurologist who completed PhD training in neuroscience; my thesis project explored microenvironmental determinants of postnatal hippocampal neural precursor cell fate. I am now completing a fellowship in neuro-oncology, and focusing my future research efforts on postnatal developmental mechanisms in brain tumor pathophysiology. This proposed research plan draws upon my background in postnatal stem and precursor cell biology, and offers the critical opportunity to develop and hone the molecular biology skills necessary for my successful transition to independence in the field of developmental neuroscience. My mentor Dr. Beachy and Co-Mentor Dr Rowitch will provide an ideal environment to develop such skills and to immerse myself in the study of developmental signaling biology in brain cancer. I will receive both didactic and hands-on training in numerous molecular techniques and will be surrounded by the technological and intellectual support to succeed. PUBLIC HEALTH RELEVANCE: Brainstem gliomas of childhood account for up to 20% of pediatric brain tumors, are frequently fatal and are poorly understood. By studying the normal brainstem during childhood, this project seeks to identify the cell of origin and molecular factors that may result in the growth of these devastating tumors. We will test the functional significance of the findings about the normal brainstem in brainstem tumor cells, which may ultimately result in new therapies for this tragic disease.