Developmental control of chromatin states in cancer

摘要 尤文肉瘤是一种儿童和年轻人的骨和软组织癌，仍然是一种高度致命的癌症。 尽管使用了激进的化疗、放射和手术。肿瘤依赖于肿瘤的发展。 一种杂交基因，它通过染色体将两个不同基因EWSR1和FLI1的部分结合在一起 易位或染色体复合体。由此产生的EWS-FLI1融合癌蛋白作为转录和染色质 调整器。从我们的实验室和其他人的工作中构建，证明EWS-FLI1获得了新的活性 调节微卫星染色质状态，成为肿瘤细胞的增强子。然而，我们有 结果表明，EWS-FLI1的活性和基因组靶向性受到潜在的表观基因组状态的影响 牢房。我们证明了原代和体外分化的间充质干细胞具有染色质状态。 与尤因肉瘤相似。我们假设，在干细胞分化过程中，一种独特的 染色质状态的发展使EWS-FLI1成为可能。此外，我们假设这种允许状态是 由染色质调节因子、特征修饰的组蛋白和特定的RNA组成。在这个项目中，我们将 使用癌细胞(目标1)和干细胞发育方法(目标2)来鉴定蛋白质和RNA 相互作用因子和组蛋白的翻译后修饰，创造一个良好的环境。我们预测 关键功能将在两个模型系统之间共享。我们将通过以下方式测试这些因素的影响 当这些因子被调节时，评估EWS-FLI1对染色质状态和转录的活性。 尤文肉瘤患者来源干细胞的产生将使我们能够评估EWS-FLI1的影响 在细胞分化的过程中。染色质可及性的综合单细胞分析 转录组将能够直接评估EWS-FLI1对染色质的影响，反过来，对染色质的影响 在EWS-FLI1上。我们将具体研究生物化学相互作用和功能关系 EWS-FLI1和转录调控因子PAX7，这是在Pilot期间发现的相互作用因子之一 实验。

SUMMARY Ewing sarcoma, a cancer of the bone and soft tissue of children and young adults, remains a highly lethal cancer despite the use of aggressive chemotherapy, radiation, and surgery. The tumor is dependent on the development of a hybrid gene that brings together parts of two different genes, EWSR1 and FLI1, through chromosomal translocation or chromoplexy. The resulting EWS-FLI1 fusion oncoprotein acts as a transcriptional and chromatin regulator. Building from the work of our lab and others demonstrating that EWS-FLI1 gains neomorphic activity to regulates chromatin state at microsatellite coopted to become enhancers in tumor cells. However, we have shown that the activity and genomic targeting of EWS-FLI1 is influenced by the underlying epigenomic state of the cell. We demonstrated that primary and in vitro differentiated mesenchymal stem cells offer a chromatin state similar to that of Ewing sarcoma. We hypothesize that during stem cell differentiation a unique permissive chromatin state develops that enables EWS-FLI1. Further, we hypothesize that this permissive state is made up of chromatin regulators, characteristically modified histones and specific RNAs. In this project we will employ cancer cell (Aim 1) and stem cell developmental approaches (Aim 2) to identify the protein and RNA interactors and the posttranslational modifications of histones that create a favorable environment. We predict that critical features will be shared between both model systems. We will test the impact of these factors by evaluating the activity of EWS-FLI1 on chromatin states and transcription when these factors are modulated. The generation of Ewing sarcoma patient derived stem cells will enable us to evaluate the impact of EWS-FLI1 across the process of cellular differentiation. Integrated single cell analytics of chromatin accessibility and the transcriptome will enable direct evaluation of the impact of EWS-FLI1 on chromatin and, reciprocally, chromatin on EWS-FLI1. We will specifically study the biochemical interaction and functional relationship between EWS-FLI1 and the transcriptional regulator PAX7, one of the interactors identified during pilot experimentation.