Hoxa9, Meis1, and Pbx in Self-renewal and Leukemogenesis

Hoxa9、Meis1 和 Pbx 在自我更新和白血病发生中的作用

基本信息

批准号：
7991341
负责人：
MARK P KAMPS
金额：
$ 36.6万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN DIEGO
依托单位国家：
美国
项目类别：
财政年份：
1992
资助国家：
美国
起止时间：
1992-04-10 至 2012-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7991341
关键词：
Acetylation Acute Myelocytic Leukemia Address Affinity Apical Binding Binding Sites Biochemical Biochemical Genetics Biology C-terminal CD34 gene Cell model Cells Collection Complex DNA DNA Binding Development Drug Delivery Systems Elements Enhancers Epigenetic Process FLT3 gene Gel Chromatography Gelshift Analysis Gene Activation Genes Genetic Genetic Transcription Genomics Global Change Goals Hematopoietic Neoplasms Heparin High Pressure Liquid Chromatography Histone H3 Histones Human Indium Individual Laboratories Lead Letters Ligation Lysine Malignant Neoplasms Maps Methylation Methyltransferase Modification Molecular Mus Myelogenous N-terminal NUP98 gene Nuclear Extract Oncogene Proteins Pattern Phenotype Point Mutation Polymerase Principal Investigator Proteins RNA Interference Recruitment Activity Regulation Reporter Repression Resolution Site Specificity Stem cells Surface System Testing Tetanus Helper Peptide Therapeutic Transcriptional Activation chromatin immunoprecipitation cofactor knock-down leukemia leukemogenesis new technology novel prevent progenitor programs promoter protein complex research study response self-renewal stemness tandem mass spectrometry transcription factor vector

项目摘要

DESCRIPTION (provided by applicant): HoxA9 and Meis1 cooperate to cause acute myeloid leukemia (AML), and are downstream effectors of a group of human AML oncoproteins, including MLL fusions. HoxA9 controls a self-renewal/differentiation switch and Meis1 confers leukemic potential, which correlates with its ability to activate transcription of stemness genes including Sox4, FLT3, and CD34. The biochemical and genetic mechanisms by which HoxA9 enforces self- renewal and by which Meis1 confers leukemic potential are not as yet understood. In this proposal, we use novel cell systems derived in our laboratory to address the key biochemical and genetic questions underlying myeloid leukemogenesis by HoxA9 and Meis1. In Aim 1, we focus on how apical oncoproteins activate transcription of Meis1. We will modulate Meis1 transcription using wild-type and conditional forms of MLL-ENL and NUP98-NSD1, a novel histone H3 Lysine 36 methyltransferase AML oncoprotein we recently discovered that coactivates transcription of Meis1 and HoxA9. Aim 2: In three different cell models, we discovered that the stem cell gene Sox4 is co-activated by HoxA9 and Meis1. Sox4 induces AML in mice and is activated in many other forms of human cancer. We hypothesize that Sox4 is a downstream effecter of HoxA9/Meis1 leukemogenesis. In Aim 2, we will characterize the Sox4 promoter, focusing on how HoxA9 and Meis1 cooperate with each other and other cofactors to activate Sox4 transcription. We hypothesize that HoxA9 and Meis1 catalyze distinct epigenetic modifications that cooperate functionally in activation. We will also deduce the requirement of Sox4 in HoxA9/Meis1 leukemogenesis, identify its genetic targets, and begin to pursue its cofactor function in establishing the AML phenotype. Aim 3: Terminal differentiation genes are strongly repressed by HoxA9, yet they are robustly activated when conditional forms of HoxA9 are switched off. In Aim 3, we will focus on how HoxA9 maintains active repression of terminal differentiation genes. For Aims 1-3, we use a novel technology called Chromatin Immunoprecipitation DNA Selection Ligation (ChIP-DSL), which will produce a high-resolution map of the histone marks of activation and repression, and of the binding sites for oncoproteins, transcription factors, and polymerases over 20 to 40 kbp of genomic DNA surrounding the transcriptional initiation site of each promoter. Lentiviral reporter vectors will be used to locate minimal promoters within responsive regions indicated by ChIP-DSL, and classical molecular and biochemical approaches will be taken to identify the activation mechanisms. Aim 4: We have already defined an N-terminal domain in HoxA9 and a C-terminal domain in Meis1 that are both required to activate transcription of Sox4, FLT3, and CD34. Our hypothesis is that each domain recruits a different histone modifying activity that cooperates in gene activation. In Aim 4, we identify cofactors that bind these domains, verify their importance in gene activation and in leukemogenesis, and begin to investigate the epigenetic changes they catalyze. These activities and the biochemical surfaces that recruit these cofactors are novel drug targets in AML. Project Narrative: This proposal focuses on how HoxA9 and Meis1 cause acute myeloid leukemia (AML) in humans, a cancer of blood stem cells. We focus on 3 of the most important questions: 1) How do human cancer proteins activate expression of the Meis1 leukemia gene? 2) How do HoxA9 and Meis1 activate expression of the Sox4 leukemia gene? 3) How does HoxA9 prevent expression of maturation genes? Discovering mechanisms underlying these questions may lead to the development of new AML therapeutics.

描述（由申请人提供）：HOXA9和MEIS1合作引起急性髓样白血病（AML），是一组人AML癌蛋白（包括MLL融合）的下游效应子。 HOXA9控制着自我更新/分化开关，Meis1赋予白血病潜力，这与其激活包括SOX4，FLT3和CD34在内的干性基因转录的能力相关。 HOXA9实施自我更新的生化和遗传机制，Meis1赋予白血病潜力的生化和遗传机制尚不清楚。在此提案中，我们使用实验室中衍生的新细胞系统来解决HOXA9和MEIS1的髓样白血病发生的关键生化和遗传问题。在AIM 1中，我们关注顶端癌蛋白如何激活MEIS1的转录。我们将使用MLL-ENL和NUP98-NSD1（一种新型组蛋白H3赖氨酸36甲基转移酶AML癌蛋白）的MLL-ENL和NUP98-NSD1的条件形式调节MEIS1转录。 AIM 2：在三种不同的细胞模型中，我们发现干细胞基因SOX4由HOXA9和MEIS1共激活。 SOX4在小鼠中诱导AML，并在许多其他形式的人类癌症中被激活。我们假设Sox4是HOXA9/MEIS1白血病发生的下游效应剂。在AIM 2中，我们将表征Sox4启动子，重点是Hoxa9和Meis1如何相互配合以及其他辅助因子激活SOX4转录。我们假设Hoxa9和Meis1催化了在激活中功能合作的不同表观遗传修饰。我们还将推断出HOXA9/MEIS1白血病发生中SOX4的需求，确定其遗传靶标，并开始在建立AML表型时追求其辅因子功能。 AIM 3：终端分化基因受HOXA9的强烈抑制，但是当有条件的HOXA9形式被关闭时，它们会被强烈激活。在AIM 3中，我们将重点关注HOXA9如何保持对终端分化基因的积极抑制。对于目标1-3，我们使用一种称为染色质免疫沉淀DNA选择连接（芯片-DSL）的新技术，该技术将生成激活和抑制的组蛋白标记的高分辨率图，以及癌蛋白，转录因子的结合位点，以及超过20至40 kbp的基因组DNA的聚合酶周围每个启动子的转录启动位点。慢病毒记者向量将用于在芯片-DSL指示的响应区域内定位最小的启动子，并将采用经典的分子和生化方法来识别激活机制。 AIM 4：我们已经定义了HOXA9中的N末端结构域和MEIS1中的C末端结构域，这些结构域都需要激活SOX4，FLT3和CD34的转录。我们的假设是，每个领域都募集了在基因激活中合作的不同组蛋白修饰活性。在AIM 4中，我们确定了结合这些结构域的辅助因子，验证它们在基因激活和白血病发生中的重要性，并开始研究它们催化的表观遗传变化。这些活动和募集这些辅助因子的生化表面是AML中的新型药物靶标。项目叙述：该提案的重点是Hoxa9和Meis1在人类（一种血液干细胞癌）中如何引起急性髓样白血病（AML）。我们关注三个最重要的问题：1）人类癌症蛋白如何激活MEIS1白血病基因的表达？ 2）HOXA9和MEIS1如何激活Sox4白血病基因的表达？ 3）HOXA9如何防止表达成熟基因？发现这些问题的基础机制可能会导致新的AML治疗剂的发展。