BAK Autoactivation in Hematological Malignancies

血液系统恶性肿瘤中的 BAK 自动激活

基本信息

批准号：
10684892
负责人：
SCOTT H KAUFMANN
金额：
$ 35.64万
依托单位：
MAYO CLINIC ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2025-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10684892
关键词：
Acute Myelocytic Leukemia American Androgen Antagonists Antineoplastic Agents Apoptosis Apoptotic BAX gene BCL-2 Protein BCL2 gene BCL2L1 gene BCL2L11 gene Binding Binding Proteins Binding Sites Biochemical Biology C-terminal Cardiolipins Cell Death Cell Line Cell Membrane Permeability Cells Cellular Stress Cessation of life Clinic Clinical Cytoplasm Data Development Disease Enzyme Inhibitor Drugs Epithelium Exposure to FDA approved Family Family member Funding Glucocorticoids Hematologic Neoplasms Hematopoietic Hematopoietic Neoplasms Higher Order Chromatin Structure Hormonal Human In Vitro Induction of Apoptosis Lead Leukemic Cell Leukocytes Life Lipid Binding Lymphoid Cell Lymphoma cell MCL1 gene MEKs Malignant Neoplasms Mediating Membrane Lipids Mitochondria Molecular Morphology Mus Myeloid Cells Nature Outer Mitochondrial Membrane PIK3CG gene PMAIP1 gene Pathway interactions Pattern Peptides Permeability Phase Play Positioning Attribute Preclinical Testing Process Protein Family Proteins Proto-Oncogene Proteins c-akt Regimen Regulation Role Sampling Seminal Specimen Stimulus Structure Testing Therapeutic Tissues antagonist anticancer treatment base biophysical analysis cancer cell cancer therapy cell type cytotoxicity design dimer drug sensitivity effective therapy experimental study improved in vivo inhibitor insight interest leukemia leukemia treatment mTOR Inhibitor member mimetics monomer novel paralogous gene postnatal research clinical testing resistance mechanism response restraint small molecule structural determinants targeted agent targeted treatment truncated BID protein tumor

项目摘要

ABSTRACT The mitochondrial apoptotic pathway plays a critical role in the response to various cellular stresses, including targeted anticancer therapies. This pathway is regulated by interactions between various members of the BCL2 family of proteins. In particular, BAX and BAK play an indispensible role in this pathway by permeabilizing the mitochondrial outer membrane (MOM). While BAX plays a predominant role in epithelial tissues, especially in postnatal life, BAK is particularly abundant in normal white blood cells, leukemia cell lines, and clinical leukemia specimens. Our previous studies have demonstrated that BAK activation is initiated by two distinct processes: i) Transient binding of BH3-only members of the BCL2 family in response to certain stimuli (e.g., transient binding of NOXA, which is upregulated in response to the NEDD8 activating enzyme inhibitor pevonedistat), and ii) concentration-dependent BAK autoactivation, a process we initially described. Once activated, BAK forms multimers that permeabilize the MOM. Our recent studies indicate that this MOM permeabilization involves the action of a C-terminal lipid binding domain that is externalized upon BAK activation and interacts with the MOM lipid cardiolipin. Counterbalancing this pro-apoptotic effect, however, BAK can be bound and neutralized by anti- apoptotic BCL2 paralogs in lymphohematopoietic cell lines and primary acute myeloid leukemia (AML) specimens. Importantly, the response of these cells to BH3 mimetics, proapoptotic small molecules that selectively bind and neutralize BCL2, BCLXL and/or MCL1, reflects which of the anti-apoptotic BCL2 family member(s) constitutively bind BAK. Collectively, these observations lead to the hypothesis that AMLs with higher BAK levels will harbor more constitutively activated BAK and will be particularly sensitive to BH3 mimetics as well as targeted therapies that activate BH3-only proteins. We now propose three aims that will test this hypothesis and provide additional insight into the action of BAK in AML during anti-leukemic therapy. First, we will assess the mechanisms responsible for high BAK expression in some AMLs but not others because high BAK expression contributes to BAK autoactivation. Second, we will determine the biochemical basis for BAK autoactivation and subsequent restraint by anti-apoptotic BCL2 family members because this partially- activated-and-then-restrained BAK is the species poised to kill leukemia cells upon exposure to BH3 mimetics and targeted therapies that upregulate BH3-only proteins. Third, we will assess the relationship between high BAK expression, BAK restraint by various anti-apoptotic BCL2 family members, and response of clinical AML to a novel pevonedistat-containing combination undergoing early phase clinical testing, thereby assessing the potential importance of constitutive BAK activation in the clinical setting. These studies, which build on our recent advances in understanding the action of BAK at the molecular level, are collectively designed to enhance current understanding of BCL2 family biology and simultaneously provide new insight into a potentially important determinant of AML sensitivity in the clinic.

抽象的线粒体凋亡途径在对各种细胞应激的反应中起着至关重要的作用，包括靶向抗癌疗法。该途径受BCL2各个成员之间的相互作用来调节蛋白质家族。特别是，Bax和Bak通过渗透在该途径中起着不可或缺的作用线粒体外膜（妈妈）。尽管Bax在上皮组织中起主要作用，但在产后寿命，BAK在正常的白细胞，白血病细胞系和临床白血病中特别丰富标本。我们以前的研究表明，BAK激活是由两个不同的过程引发的： i）响应某些刺激（例如，瞬态结合 NOXA的响应于NEDD8激活酶抑制剂pevonedistat）和 ii）依赖浓度的BAK自动激活，这是我们最初描述的过程。一旦激活，Bak形成了使妈妈渗透的多聚体。我们最近的研究表明，这个妈妈的通透涉及 C末端脂质结合结构域的作用，该结合结构域在BAK激活后被外部化并与MOM相互作用脂质心磷脂。但是，平衡这种促凋亡效应，bak可以通过抗抗淋巴瘤细胞系中的凋亡BCL2旁系同源物和急性髓样白血病（AML）标本。重要的是，这些细胞对BH3模拟物的反应，促凋亡的小分子有选择地结合并中和Bcl2，BCLXL和/或MCL1反映了抗凋亡BCl2家族的哪个成员组成型结合bak。总的来说，这些观察结果导致了以下假设较高的BAK水平将具有更多组成型激活的Bak，并且对BH3特别敏感模拟物以及激活仅BH3蛋白的靶向疗法。我们现在提出三个目标将检验这一假设，并提供对抗白血病治疗期间BAK在AML中的作用的更多见解。首先，我们将评估负责某些AML中高面积表达的机制，而不是其他AML，因为高面包表达有助于BAK自动激活。其次，我们将确定生化基础抗凋亡Bcl2家族成员的自动激活和随后的克制，因为这部分激活和激活的bak是有望在暴露于BH3 Mimetics时杀死白血病细胞的物种并针对上调仅BH3蛋白的靶向疗法。第三，我们将评估高高之间的关系 Bak表达，各种抗凋亡BCL2家族成员的BAK约束，以及临床AML对一种新型的含Pevonedistat的组合正在进行早期临床测试，从而评估了本构型BAK激活在临床环境中的潜在重要性。这些研究，建立在我们最近的理解BAK在分子层的作用的进步，旨在增强电流了解BCL2家庭生物学，并同时提供有关潜在重要重要的新见解临床中AML灵敏度的决定因素。