Precursor cell-niche interactions and the genesis of brainstem gliomas

描述(申请人提供)：脑干胶质瘤是一组异质性肿瘤，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%。其中大多数是弥漫浸润性脑桥腹侧胶质瘤，这是一种毁灭性的癌症，发生在学龄儿童(7岁时达到顶峰)，几乎总是会导致死亡。与之形成鲜明对比的是，发生在脑桥、中脑或延髓的胶质瘤通常无痛，预后良好。腹侧桥脑胶质瘤(弥漫性桥脑胶质瘤)和背侧发生的胶质瘤之间的这种明显的解剖和病理差异表明潜在的细胞或微环境过程的失调，这一点尚未确定。我推测，儿童脑桥腹侧胶质瘤的发生是由于出生后前体细胞、微环境或两者的特殊失调。为了支持这一假设，初步研究发现，在儿童时期，人类腹侧脑桥中存在一组新的神经前体细胞。我们还培养了第一个可用的人类脑桥腹侧胶质瘤细胞培养物，并从肿瘤中分离出一种神经干细胞样细胞类型。这代表着对这种肿瘤的研究取得了重大进展，到目前为止，由于可供研究的组织稀缺和没有实验模型系统，这种肿瘤的研究一直受到限制。拟议的实验计划概述了对正常人和小鼠脑干腹背轴的干细胞、谱系限制的前体细胞和神经胶质细胞种群的系统评估，以及对出生后脑干信号微环境腹背差异的类似系统检查，最后测试已确定的候选信号通路和弥漫性桥脑胶质瘤细胞的假定起源细胞的功能意义。所使用的技术包括荧光免疫组织化学和共聚焦显微镜、免疫激光捕获显微切割、细胞培养、移植研究、流式细胞仪、基因表达微阵列分析、单细胞聚合酶链式反应和遗传细胞命运图谱。我是一名神经学家，完成了神经科学方面的博士培训；我的论文项目探索了出生后海马神经前体细胞命运的微环境决定因素。我现在正在完成神经肿瘤学的奖学金，并将我未来的研究重点放在脑肿瘤病理生理学的出生后发育机制上。这项拟议的研究计划利用了我在出生后干细胞和前体细胞生物学方面的背景，并提供了发展和磨练我在发育神经科学领域成功过渡到独立所需的分子生物学技能的关键机会。我的导师Beachy博士和共同导师Rowitch博士将提供一个理想的环境来发展这种技能，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，并将被成功的技术和智力支持所包围。 公共卫生相关性：儿童脑干胶质瘤占儿童脑肿瘤的20%，通常是致命的，而且人们对此知之甚少。通过研究儿童时期的正常脑干，这个项目试图确定可能导致这些毁灭性肿瘤生长的起源细胞和分子因素。我们将测试脑干肿瘤细胞中正常脑干的发现的功能意义，这可能最终导致这种悲剧性疾病的新疗法。

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.