Function and Regulation of the BCL-2 Family

BCL-2 家族的功能和调节

• 批准号: 10576308
• 负责人: Jerry Edward Chipuk
• 金额: $ 37.89万
• 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/10576308
• 关键词: Affinity; Apoptosis; Apoptotic; BCL-2 Protein; BCL2L11 gene; Binding; Biochemical; Biological Models; Biophysics; Cancer Biology; Cancer Etiology; Cancer Model; Carbon; Caspase; Cell Membrane Permeability; Cells; Chemoresistance; Chemotherapy and/or radiation; Classification; Clinical; Collaborations; 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 therapeutic intervention; prevent; programs; protein B; protein activation; protein function; protein protein interaction; screening; sensor; small molecule; success; treatment response; 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.

项目总结