Chemical Modulation of Chromatin Signaling in Lymphoid Malignancies

淋巴恶性肿瘤中染色质信号传导的化学调节

基本信息

批准号：
8929198
负责人：
Christopher J Ott
金额：
$ 9.81万
依托单位：
DANA-FARBER CANCER INST
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-18 至 2017-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8929198
关键词：
Acute Lymphocytic Leukemia Animal Model Binding Biochemical Biological Assay Biology Bromodomain Cell Line Cell Proliferation Cell model Cells Cellular Assay Cellular biology ChIP-seq Chemicals Chemistry Chromatin Chromatin Structure Chromosomal Rearrangement Clinical Research DNA Modification Methylases Dependence Dependency Development Distal Down-Regulation Drug Targeting Elements Enhancers Epigenetic Process FDA approved Gene Expression Gene Expression Regulation Genes Genetic Genetic Transcription Genome Health Hematologic Neoplasms Histone Acetylation Histone Deacetylase Histone Deacetylase Inhibitor Histones Human IL7R gene In Vitro Lead Ligands Lysine MYC gene Malignant Neoplasms Malignant lymphoid neoplasm Mediating Mentors Modeling Mus Nature Oncogenes Oncogenic Output Pharmaceutical Chemistry Pharmaceutical Preparations Pharmacologic Substance Proteins Proto-Oncogene Proteins c-myc Reader Regulatory Pathway Research Role Seasons Signal Transduction System Testing Therapeutic Translations Up-Regulation Xenograft Model Xenograft procedure base cancer cell cell growth cell type chromatin protein combinatorial epigenome genome-wide genome-wide analysis high throughput screening histone acetyltransferase inhibitor/antagonist insight interest leukemia leukemogenesis malignant phenotype next generation novel promoter screening small molecule tool transcription factor

项目摘要

DESCRIPTION (provided by applicant): Genetic aberrations in lymphoid malignancies, including acute lymphoblastic leukemias (ALLs), often include chromosomal rearrangements that result in the dramatic upregulation or dysregulation of transcription factors and other chromatin-associating proteins. This results in altered chromatin states and transcriptional outputs that lead to increased cellular proliferation and other malignant phenotypes. While the activity of transcription factors is very difficult to inhibit directly with small molecule drugs, chromatin-associating transcription co- factors that bind to histones have recently been shown to be amenable to small molecule inhibition. We have discovered and developed chemical probes for a class of protein modules called bromodomains, which are principally involved in the recognition of acetylated lysines on histones. Using these chemical probes, we have established a rationale for targeting this class of proteins in ALL. Treatment of ALL cells with bromodomain inhibitors leads to a dramatic reduction in expression of specific ALL oncogenes, including the notoriously 'undruggable' oncogenic transcription factor MYC. Selective disruption of oncogene expression leads to a decrease in ALL cell proliferation both in vitro and in murine xenograft models. The studies proposed here aim to characterize the mechanism by which bromodomain inhibition selectively effects specific oncogene expression in ALL cells, and to use these insights to further exploit putative ALL cell dependencies on chromatin-associating factors. Ours studies show that loss of MYC expression is a direct result of inhibiting the bromodomain-containing protein BRD4 from the MYC gene locus, leading to the hypothesis that BRD4 is an ALL-dependency gene. However, as BRD4 is widely expressed in many cell types, it remains to be seen how its inhibition leads to potent anti-ALL effects. In Aim 1, we will perfor genome-wide studies of bromodomain protein displacement with chemical probes using ChIP-seq, particularly focusing on effects within promoter distal cis-regulatory control elements of the genome, or enhancers. In Aim 2 we will study bromodomain inhibition in combination with other chromatin-targeting small molecules in ALL cells, primarily focusing on compounds that target histone acetylation including histone deacetylase and acetyltransferase probes. We will model these potential therapeutic combinations in murine models of disseminated ALL. Aim 3 of this proposal seeks to expand the chemical toolbox of chromatin-targeting small molecules, specifically focusing on the bromodomain of the ATAD2 protein, a MYC co-activator that is highly expressed in ALL. We will use high- throughput compound screening and iterative medicinal chemistry employing a suite of optimized bromodomain-binding assay systems. To achieve these aims, I have assembled an excellent and seasoned advisory team, including Dr. James Bradner [Mentor, DFCI], an expert in chemical biology and hematologic malignancies; Dr. Thomas Look [Co-mentor, DFCI] an expert in leukemogenesis and animal models of ALL; and Dr. Richard Young [Co-mentor, MIT], an expert in chromatin biology and transcriptional networks.

描述（由申请人提供）：淋巴恶性肿瘤（包括急性淋巴细胞白血病（ALL））中的遗传畸变通常包括染色体重排，导致转录因子和其他染色质相关蛋白的急剧上调或失调。这会导致染色质状态和转录输出发生改变，从而导致细胞增殖和其他恶性表型增加。虽然转录因子的活性很难用小分子药物直接抑制，但与组蛋白结合的染色质相关转录辅助因子最近已被证明适合小分子抑制。我们发现并开发了一类称为溴结构域的蛋白质模块的化学探针，该蛋白质模块主要参与组蛋白上乙酰化赖氨酸的识别。使用这些化学探针，我们已经建立了针对 ALL 中此类蛋白质的基本原理。用溴结构域抑制剂治疗 ALL 细胞会导致特定 ALL 致癌基因的表达急剧减少，包括众所周知的“不可成药”致癌转录因子 MYC。选择性破坏癌基因表达会导致体外和小鼠异种移植模型中 ALL 细胞增殖的减少。本文提出的研究旨在表征溴结构域抑制选择性影响 ALL 细胞中特定癌基因表达的机制，并利用这些见解进一步利用假定的 ALL 细胞对染色质相关因子的依赖性。我们的研究表明，MYC 表达的丧失是抑制 MYC 基因座中含溴结构域蛋白 BRD4 的直接结果，从而得出 BRD4 是 ALL 依赖性基因的假设。然而，由于 BRD4 在许多细胞类型中广泛表达，其抑制如何导致有效的抗 ALL 作用仍有待观察。在目标 1 中，我们将使用 ChIP-seq 使用化学探针对溴结构域蛋白置换进行全基因组研究，特别关注启动子远端顺式调控元件内的影响基因组或增强子。在目标 2 中，我们将在 ALL 细胞中与其他染色质靶向小分子结合研究溴结构域抑制，主要关注针对组蛋白乙酰化的化合物，包括组蛋白脱乙酰酶和乙酰转移酶探针。我们将在播散性 ALL 小鼠模型中模拟这些潜在的治疗组合。该提案的目标 3 旨在扩展染色质靶向小分子的化学工具箱，特别关注 ATAD2 蛋白的溴结构域，这是一种在 ALL 中高度表达的 MYC 共激活剂。我们将采用高通量化合物筛选和迭代药物化学，并采用一套优化的溴结构域结合测定系统。为了实现这些目标，我组建了一支优秀且经验丰富的顾问团队，其中包括詹姆斯·布拉德纳博士（DFCI 导师），他是化学生物学和血液恶性肿瘤方面的专家； Thomas Look 博士 [DFCI 联合导师] 白血病发生和 ALL 动物模型方面的专家； Richard Young 博士（麻省理工学院联合导师），染色质生物学和转录网络专家。