Modeling pediatric glioma in human ES cells:mechanistic and therapeutic insights

摘要/项目摘要 DIPG是儿童期快速致命的脑肿瘤。大多数患者在一个月内死亡。 诊断需要一两年的时间，因为这种毁灭性的疾病没有有效的治疗方法。他们的 脑干中的关键位置长期以来一直禁止接触肿瘤组织。最近， 测序研究揭示了由单个氨基酸组成的新的组蛋白突变 组蛋白H3变体的尾部中的取代。一种排他共现的模式 具有特定信号通路改变的组蛋白突变以及发病年龄和脑 出现了区域变化。利用这些数据和严格的发展 肿瘤的窗口，我们的团队已经建立了有效的第一个基因工程 基于人ES细胞的肿瘤模型。该模型产生的肿瘤重现了 遗传，转录组，表观遗传和疾病的组织学特征，从而提供 研究这种疾病的宝贵工具。全基因组研究表明， 突变导致细胞的发育状态重置为更早更原始的状态， 干细胞状态 重要的是，我们的建模系统是药物筛选的有效平台， 从而鉴定出一种新的蛋白质-蛋白质相互作用网络作为一个关键组成部分 这些肿瘤的增殖和生长机制，集中在蛋白质menin。 Menin是一种具有多个伴侣的独特蛋白质，在MLL中具有致癌性 重排白血病我们的数据表明，沉默menin或抑制其MLL相互作用， menin抑制剂导致增殖减少和细胞死亡增加，这是一种全新的 这一发现从未在神经胶质瘤中报道过，这为治疗策略带来了希望。 该提案旨在通过构建新模型来扩展我们的hES建模平台， 是脑干中描述的体细胞突变的遗传多样性的代表。 神经胶质瘤我们还将研究组蛋白突变的下游事件，重点是 menin致癌作用的分子基础。最终目标是开发一种治疗 DIPG的策略，利用新合成的menin抑制剂。 我们的研究也将有助于将hES细胞开发成更广泛应用的细胞。 癌症建模平台，利用其许多优势，包括访问 无限量供应阶段适当的人类细胞，用于机制或治疗研究， 能够从启动到肿瘤维持的步骤研究肿瘤生物学， 使用复杂的基因工具

Abstract / Project Summary DIPGs are rapidly lethal brain tumors of childhood. The majority of patients die within a year or two of diagnosis, as there is no effective treatment for this devastating disease. Their critical location in the brainstem has long prohibited access to tumor tissue. Recently, sequencing studies revealed novel histone mutations consisting of single amino acid substitutions in the tail of the histone H3 variants. A pattern of exclusive co-occurrence of histone mutations with specific signaling pathway alterations as well as age of onset and brain region alterations emerged. Taking advantage of these data and of the strict developmental window of the tumors, our team has built what is effectively the first genetically-engineered human ES cell-based model of a tumor. The model yielded tumors that recapitulated the genetic, transcriptomal, epigenetic and histological features of the disease, thus providing valuable tools for the study of the disease. Genome wide studies suggested that the histone mutation led to a resetting of the developmental status of the cells to an earlier more primitive stem cell state. Importantly, our modeling system served as an effective platform for drug screens, leading to the identification of a novel protein –protein interaction network as a key component of the proliferative and growth machinery of these tumors, centered on the protein menin. Menin is a unique protein with multiple partners; it is oncogenic in the context of the MLL rearranged leukemias. Our data show that silencing menin or inhibiting its MLL interaction with a menin inhibitor leads to a decrease in proliferation and increased cell death, a completely novel finding never reported in glioma, that raises the promise of a therapeutic strategy. The proposal aims to expand our hES modeling platform by building new models that are representative of the genetic diversity of the somatic mutations described in brainstem gliomas. We will also study the events downstream of the histone mutations, with emphasis on the molecular basis of the oncogenic role of menin. The ultimate goal is to develop a therapeutic strategy for DIPGs, taking advantage of newly synthesized menin inhibitors. Our studies should also contribute to developing hES cells into a more widely applicable platform for cancer modeling capitalizing on their many advantages, including access to an unlimited supply of stage appropriate human cells for mechanistic or therapeutic studies, the ability to study tumor biology from the step of initiation to tumor maintenance, and the ease of implementing sophisticated genetic tools.