Small molecule probes of MYC stability and function intumorigenesis

MYC稳定性和肿瘤发生功能的小分子探针

基本信息

批准号：
10570873
负责人：
Sarki A. Abdulkadir
金额：
$ 55.95万
依托单位：
NORTHWESTERN UNIVERSITY AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-03-01 至 2026-02-28
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10570873
关键词：
3-Dimensional ATAC-seq Affect Animal Model Architecture Binding Biochemical Biology Cancer Model Cell Proliferation Cell Survival Cell physiology Cells Cellular Stress Cessation of life Chemicals Chromatin Chromatin Structure Combined Modality Therapy Complement Complex Computer Assisted Consensus Coupled DNA DNA Binding Dependence Drug Kinetics Epigenetic Process Event Family Gene Expression Genes Genetic Transcription Genome Genomics Helix-Turn-Helix Motifs Human In Vitro Knowledge MYC Family Protein MYC gene Malignant Neoplasms Malignant neoplasm of lung Malignant neoplasm of prostate Maps Mediating Modeling Oncogenes Oncogenic Oncoproteins Output Pathway interactions Pharmaceutical Preparations Phosphorylation Play Proliferating Proteasome Inhibitor Proteins Publishing Recurrence Role Series Site Stress Testing Therapeutic Threonine Toxicology Transcriptional Activation Tumorigenicity Ubiquitin Up-Regulation Work activating transcription factor antitumor effect biological adaptation to stress c-myc Genes cytokine efficacy study genetic manipulation genome-wide genomic locus glycogen synthase kinase 3 beta in silico in vivo inhibitor knock-down leukemia member multicatalytic endopeptidase complex neoplastic cell novel novel strategies overexpression programs recruit response screening small molecule small molecule inhibitor transcription factor transcriptome sequencing tumor tumor microenvironment tumorigenesis

项目摘要

ABSTRACT MYC oncoproteins (including c-MYC, L-MYC and N-MYC) play critical roles in the initiation, progression and recurrence of many human malignancies. Extensive studies indicate that MYC is required to maintain tumor cell survival and proliferation. We have recently used a novel approach that combined computer-aided modeling with a rapid in vivo screen to develop a new series of direct small molecule inhibitors (MYCi’s) that show excellent selectivity, potency and tolerability in multiple MYC-driven cancer models. These compounds demonstrate a dual mechanism of action. First, direct binding of MYCi to MYC in the basic helix-loop-helix (bHLH) region disrupts complex formation with MYC which is required for MYC transcriptional activity. Secondly, binding of MYCi enhances MYC phosphorylation on threonine-58 (pT58) which promotes MYC degradation via the ubiquitin-proteasome pathway. However the key downstream effectors of these events and how they might impact cellular function are unknown. Reduction of MYC protein and enhanced pT58MYC may be expected to have profound effects on MYC family protein interactions with each other and with chromatin. In this regard, we have observed in preliminary studies that MYCi leads to selective loss of MYC at genomic loci enriched for master chromatin regulators (CTCF and FOX), suggesting disruption of the 3D architecture of the MYC-bound genome in response to MYCi. Additionally, unfolded MYC due to MYCi binding and/or enhanced MYC degradation may provoke a cellular stress response. Using unbiased ATAC-seq and RNA-seq approaches, we found that MYCi treatment activates the ATF4/CHOP stress response pathway. Importantly, activation of ATF4/CHOP by MYCi is an on-target, MYC-dependent effect. ATF4 mediates MYCi antitumor activity as ATF4 depletion partially ameliorates the antitumor effects of MYCi. Furthermore, we propose that MYCi-induced ATF4 cytokines modulate the tumor microenvironment. Activation of the ATF4 pathway by MYCi exposes potential therapeutic vulnerabilities for rational combination approaches, such as combination of MYCi with proteasome inhibitors that activates ATF4. Based on the preliminary findings, our central hypotheses is that MYCi inhibits MYC-dependent tumorigenesis by a dual-pronged mode of action. First, MYCi affects MYC family target gene expression by disrupting MYC/MAX interaction and by promoting MYC degradation. Secondly, binding of MYCi to MYC and/or MYC degradation activates an ATF4/CHOP stress response pathway that suppresses tumor cell viability. We propose the following specific aims to test these hypotheses: Aim 1). To investigate the mechanisms by which MYC inhibitor modulates MYC transcriptional activity and the epigenetic landscape. We will investigate the consequences of MYCi treatment on the recruitment of MYC, pT58MYC, and associated factors to chromatin; changes to 3D chromatin architecture; as well as the effects on MYC-driven transcriptional output in tumor cells vitro and in vivo. Aim 2). To define the mechanisms and functional consequences of ATF4/CHOP pathway activation by MYCi. We will determine mechanism of ARF4 upregulation by MYCi; define the role of MYCi- induced ATF4 in regulating target gene expression, cell viability and tumorigenicity; and assess strategies that exploit the consequences of ATF4 activation as a means of enhancing MYCi anti-tumor efficacy. These studies are significant as MYC is implicated in the majority of human cancers. The studies advance the use of MYCi as chemical probes to unmask distinct biology that complements the knowledge derived from genetic manipulations of MYC proteins. The findings will contribute to the efforts aimed at developing small molecule MYCi as potential therapeutics. Specifically, this work indicates that small-molecule MYC inhibitors have an additional anti-tumor effect due to the activation of the ATF4 pathway beyond the antitumor effects of suppressing MYC function. Finally, understanding this on-target ATF4 response provoked by small-molecule MYCi will provide rational strategies for combination therapy to enhance MYCi efficacy.

抽象的 MYC癌蛋白（包括c-MYC、L-MYC和N-MYC）在起始、进展和进展中发挥关键作用许多人类恶性肿瘤的复发表明，MYC 是维持肿瘤细胞所必需的。我们最近使用了一种将计算机辅助建模与生存和增殖相结合的新方法。快速体内筛选，开发一系列新的直接小分子抑制剂（MYCi），显示出优异的效果这些化合物在多种 MYC 驱动的癌症模型中表现出选择性、效力和耐受性。首先，MYCi 与 MYC 在碱性螺旋-环-螺旋 (bHLH) 区域直接结合。破坏与 MYC 的复合物形成，这是 MYC 转录活性所必需的。 MYCi 增强苏氨酸 58 (pT58) 上的 MYC 磷酸化，从而通过然而，这些事件的关键下游效应器以及它们如何发挥作用。 MYC 蛋白的减少和 pT58MYC 的增强可能会影响细胞功能。 MYC 家族蛋白之间以及与染色质的相互作用具有广泛的影响。在初步研究中观察到，MYCi 会导致 MYC 在富含 MYC 的基因组位点选择性丢失。主染色质调节因子（CTCF 和 FOX），表明 MYC 结合的 3D 结构被破坏另外，由于 MYCi 结合和/或增强的 MYC，基因组响应 MYCi 而展开 MYC。我们使用无偏 ATAC-seq 和 RNA-seq 方法，降解可能会引发细胞应激反应。发现 MYCi 治疗可激活 ATF4/CHOP 应激反应通路，重要的是，激活了 ATF4/CHOP 应激反应通路。 MYCi 的 ATF4/CHOP 是一种靶向、MYC 依赖性效应，与 ATF4 一样介导 MYCi 抗肿瘤活性。耗尽部分改善了 MYCi 的抗肿瘤作用此外，我们提出 MYCi 诱导的 ATF4。细胞因子调节肿瘤微环境 MYCi 激活 ATF4 通路具有潜力。合理组合方法的漏洞，例如 MYCi 与蛋白酶体的组合激活 ATF4 的抑制剂根据初步发现，我们的中心假设是 MYCi 抑制。通过双管齐下的作用模式实现 MYC 依赖性肿瘤发生首先，MYCi 影响 MYC 家族靶基因。其次，通过破坏 MYC/MAX 相互作用和促进 MYC 降解来抑制 MYCi 的表达。 MYC 和/或 MYC 降解激活 ATF4/CHOP 应激反应途径，抑制肿瘤细胞我们提出以下具体目标来检验这些假设：目标 1)。我们将研究 MYC 抑制剂调节 MYC 转录活性和表观遗传景观。 MYCi 治疗对 MYC、pT58MYC 和染色质相关因子募集的影响； 3D 染色质结构的变化以及对肿瘤细胞中 MYC 驱动的转录输出的影响；目标 2) 确定 ATF4/CHOP 途径的机制和功能后果。我们将确定 MYCi 上调 ARF4 的机制；定义 MYCi- 的作用；诱导 ATF4 调节靶基因表达、细胞活力和致瘤性；并评估策略；利用 ATF4 激活的结果作为增强 MYCi 抗肿瘤功效的手段。这些研究意义重大，因为 MYC 与大多数人类癌症有关。使用 MYCi 作为化学探针来揭示独特的生物学，补充了从 MYC 蛋白的基因操作将有助于开发小型蛋白。具体来说，这项工作表明小分子 MYC 抑制剂是一种潜在的治疗方法。由于 ATF4 通路的激活，除了抗肿瘤作用之外，还具有额外的抗肿瘤作用最后，了解小分子引发的这种靶向 ATF4 反应。 MYCi将为联合治疗提供合理策略，以增强MYCi疗效。