Function and Regulation of the BCL-2 Family

BCL-2 家族的功能和调节

• 批准号: 9889679
• 负责人: Jerry Edward Chipuk
• 金额: $ 38.66万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-03-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/9889679
• 关键词: Affinity; Apoptosis; Apoptotic; BAX gene; BCL-2 Protein; BCL2 gene; BCL2L11 gene; Binding; Biochemical; Biological Models; Biophysics; Cancer Biology; Cancer Etiology; Cancer Model; Carbon; Caspase; Cells; Cellular Structures; Chemotherapy and/or radiation; Classification; Clinical; Coupled; Cytoplasm; Data; Environment; Excision; Family; Fibroblasts; Foundations; Human; Knowledge; Laboratories; Lead; Lipids; Maintenance; Malignant Neoplasms; Mediating; Mitochondria; Modeling; Molecular; Molecular Conformation; Mus; Outer Mitochondrial Membrane; Pathway interactions; Phase; Phenotype; Process; Proteins; Proteolipids; Radiation therapy; Regulation; Research; Resistance; Role; Sphingolipids; Stress; Structure; System; Techniques; Therapeutic; Validation; Xenograft procedure; analog; biophysical techniques; cancer cell; cancer therapy; cell injury; cell suicide; cheminformatics; experimental study; insight; malignant state; melanoma; mitochondrial membrane; mutant; novel; novel therapeutics; prevent; programs; protein activation; protein function; protein protein interaction; response; screening; sensor; small molecule; structured data; success; tumor initiation; tumorigenesis; virtual screening

PROJECT SUMMARY The impact of the mitochondrial pathway of apoptosis on cancer biology is broad because the BCL-2 (B-cell CLL/Lymphoma 2) family regulates tumor initiation and maintenance, and is directly targeted by anti- cancer therapies. Therefore, a mechanistic understanding of BCL-2 family function will advance our knowledge of the pathways that cause cancer, and are clinically targeted to cure cancer. The mitochondrial pathway of apoptosis proceeds when the BCL-2 family collaborates to compromise the outer mitochondrial membrane (OMM). This process, referred to as mitochondrial outer membrane permeabilization (MOMP), allows for pro- apoptotic factors within mitochondria to gain access to the cytoplasm, which leads to caspase activation and rapid dismantling and removal of the targeted cell. BAX (BCL-2 associated X protein) is the major pro-apoptotic BCL-2 protein that engages MOMP by creating proteolipid pores in the OMM. BAX-dependent MOMP inhibits tumorigenesis, and on the flipside, BAX-dependent apoptosis is induced by a majority of conventional and targeted chemotherapeutics. In order for BAX to gain pro-apoptotic function, it has two general requirements: (1) BAX needs to interact with a subset of the pro-apoptotic BCL-2 family: the “direct activator” BH3-only proteins, e.g., BID and BIM; and (2) BAX requires stable interactions with mitochondrial lipids to structurally rearrange leading to BAX’s insertion, oligomerization, and pore formation. While decades of research have focused on understanding the first requirement, little has been discovered on how mitochondrial environment mechanistically contributes to MOMP. Over the years, my laboratory showed that mitochondrial environment directly controls BAX function, and the mitochondrial-produced 16-carbon sphingolipid metabolite 2-trans- hexadecenal (2-t-hex) is required for BAX activation and BAX-dependent apoptosis. By utilizing novel mitochondrial model systems coupled with state-of-the-art biochemical, cellular, and structural techniques, we are now ready to determine the mechanistic contributions of 2-t-hex within the BAX activation process, and more broadly, to reveal how 2-t-hex binding defines functional classifications within the BCL-2 family. Furthermore, we generated evidence that cancer cells specifically disrupt the cooperation between BAX and 2- t-hex leading to apoptotic resistance – and identified ‘first-in-class’ small molecules to overcome this phenotype. Our broad objectives are to build a foundation of novel mechanistic insights into the role of 2-t-hex on BAX-dependent apoptosis and the BCL-2 family, and to use this information to develop novel therapeutic strategies against cancer. These objectives will be accomplished in three complementary aims: (1) Define the molecular mechanism of 2-t-hex mediated BAX activation; (2) Elucidate the molecular mechanism by which S- nitrosylation of BAX promotes apoptotic resistance in cancer; and (3) Identify, refine, and characterize “first-in- class” therapeutics that transform S-nitrosylated BAXCys62 from apoptosis-resistant to apoptosis-competent thus promoting chemotherapeutic success.

项目概要 线粒体凋亡途径对癌症生物学的影响是广泛的，因为 BCL-2 （B 细胞 CLL/淋巴瘤 2）家族调节肿瘤的发生和维持，并直接被抗 癌症疗法。因此，对 BCL-2 家族功能的机械理解将增进我们的知识 导致癌症的途径，并在临床上有针对性地治愈癌症。线粒体途径 当 BCL-2 家族合作损害线粒体外膜时，细胞凋亡就会发生 （天啊）。这个过程被称为线粒体外膜透化（MOMP），允许亲 线粒体内的凋亡因子进入细胞质，从而导致 caspase 激活和 快速拆解和去除目标细胞。 BAX（BCL-2 相关 X 蛋白）是主要的促凋亡蛋白 BCL-2 蛋白通过在 OMM 中创建蛋白脂质孔来与 MOMP 结合。 BAX 依赖性 MOMP 抑制 肿瘤发生，另一方面，BAX 依赖性细胞凋亡是由大多数传统和 靶向化疗。为了使BAX获得促凋亡功能，它有两个一般要求： (1) BAX 需要与促凋亡 BCL-2 家族的一个子集相互作用：仅“直接激活剂”BH3 蛋白质，例如 BID 和 BIM； (2) BAX 需要与线粒体脂质稳定相互作用，以在结构上 重新排列导致 BAX 的插入、低聚和孔形成。虽然数十年的研究已经 专注于理解第一个要求，但关于线粒体环境如何 机械地有助于 MOMP。多年来，我的实验室表明线粒体环境 直接控制 BAX 功能，线粒体产生的 16 碳鞘脂代谢物 2-反式- 十六烯醛 (2-t-hex) 是 BAX 激活和 BAX 依赖性细胞凋亡所必需的。通过利用小说 线粒体模型系统与最先进的生化、细胞和结构技术相结合，我们 现在准备好确定 2-t-hex 在 BAX 激活过程中的机械贡献，并且 更广泛地说，揭示 2-t-hex 结合如何定义 BCL-2 家族内的功能分类。 此外，我们获得的证据表明癌细胞特异性破坏 BAX 和 2- t-hex 导致细胞凋亡抵抗——并确定了“一流”的小分子来克服这一问题 表型。我们的总体目标是为 2-t-hex 的作用建立新颖的机制见解的基础 BAX 依赖性细胞凋亡和 BCL-2 家族的研究，并利用这些信息开发新的治疗方法 对抗癌症的策略。这些目标将通过三个互补的目标来实现： (1) 定义 2-t-hex介导的BAX激活的分子机制； (2) 阐明S-的分子机制 BAX 的亚硝基化促进癌症的细胞凋亡抵抗； (3) 识别、细化和描述“首创” 类”疗法，将 S-亚硝基化的 BAXCys62 从抗凋亡转变为有凋亡能力 促进化疗成功。