Targeting the Hedgehog Pathway in Pediatric Brain Tumors

这是一个非常成功的项目的竞争更新，该项目涉及Hh途径在以下方面的作用： 髓母细胞瘤以前，我们使用Hh的小分子拮抗剂获得了戏剧性的结果， 在髓母细胞瘤的自发小鼠模型中观察到HhAntag通路。然而，最近，我们也发现， HhAntag治疗幼鼠会导致骨骼发育严重缺陷。我们现在要调查 HhAntag在肿瘤细胞以及发育中的骨中的作用机制，以优化 为人类髓母细胞瘤的一个亚群提供这种潜在的革命性治疗。我们还将 建立新的小儿脑肿瘤模型，以研究HhAntag在人体中的作用机制 髓母细胞瘤以及更广泛的儿科脑肿瘤。在目标1中，我们将讨论 HhAntag的抗肿瘤作用及其对骨发育的作用的机制。我们 将研究替代的输送方法和不同结构类别的抑制剂， 尽量减少对骨骼发育的有害影响。我们还将筛选其他抑制剂或靶点， 可能对脑肿瘤更有选择性。在目标2中，我们建议研究 在维持Hh通路活性的体外微环境中。我们将利用干细胞培养技术， 与基质支持细胞，并移植，试图维持途径的活性，在小鼠 髓母细胞瘤细胞一旦建立，我们将利用这些条件来繁殖人类 携带PTCH 1突变的髓母细胞瘤，这样我们就可以测试它们对HhAntag的反应。在目标3中，我们 研究Hh通路在缺乏已知Hh通路突变的小儿脑肿瘤中的作用。 将收集肿瘤并通过基因组分析进行表征，并用于建立新的培养物和 移植模型我们将研究HhAntag对肿瘤和基质支持细胞的作用， 一系列肿瘤，包括非典型畸胎瘤/横纹肌样瘤和脉络丛癌。

This is a competing renewal of a highly succesful project concerning the role of the Hh pathway in medulloblastoma. Previously, we obtained dramatic results using a small molecule antagonist of the Hh pathway (HhAntag) in a spontaneous mouse model of medulloblastoma. However, recently, we also found that HhAntag treatment of young mice causes severe defects in bone development. We will now investigate the mechanism of action of HhAntag in tumor cells, as well as in developing bone, to optimize strategies for delivering this potentially revolutionary treatment for a subset of human medulloblastoma. We will also establish new pediatric brain tumor models to investigate the mechanism of action of HhAntag in human medulloblastoma as well as in a broader spectrum of pediatric brain tumors. In Aim 1, we will address the mechanism responsible for the anti-tumor effect of HhAntag as well as its effect on bone development. We will investigate alternative delivery methods and different structural classes of inhibitors in an effort to minimize the deletrious effects on developing bone. We will also screen for other inhibitors or targets that may be more selective for brain tumors. In Aim 2, we propose to investigate the role of the microenvironment in maintaining Hh pathway activity in vitro. We will utilize stem cell culture techniques, coculture with stromal support cells, and transplantation in an attempt to maintain pathway activity in mouse medulloblastoma cells. Once established, we will use these conditions to propagate human medulloblastoma carrying PTCH1 mutations so that we can test their response to HhAntag. In Aim 3, we will investigate the role of the Hh pathway in pediatric brain tumors lacking known Hh pathway mutations. Tumors will be collected and characterized by genomic profiling, and used to establish new culture and transplantation models. We will investigate the effect of HhAntag on tumors and stromal support cells in a range of tumors, including Atypical Teratoid/Rhabdoid Tumors and Choroid Plexus Carcinoma.