PROJECT 3

项目3

• 批准号: 10474982
• 负责人: Hideki Aihara
• 金额: $ 36.57万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-09 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10474982
• 关键词: 2' -Deoxythymidine; APOBEC3F gene; Achievement; Active Sites; Address; Adjuvant; Affinity; Binding; Biological Assay; C-terminal; CCL21 gene; Cancer Etiology; Catalytic Domain; Cells; Chemicals; Clinical; Closure by clamp; Complex; Computer Models; Crystallization; Cytosine; DNA; DNA Binding; DNA Damage; DNA Repair; DNA Sequence; DNA biosynthesis; Data; Deaminase; Deamination; Deoxycytidine; Development; Diagnosis; Dinucleoside Phosphates; Disease; Drug resistance; Enzymes; Estrogen receptor positive; Evolution; Family; Family member; Foundations; Future; GTP-Binding Protein alpha Subunits, Gs; Genome; Genomics; Goals; Histidine; Human; In Vitro; Innate Immune Response; Knowledge; Length; Life; Malignant Neoplasms; Mediating; Molecular; Molecular Chaperones; Molecular Conformation; Monoclonal Antibodies; Mutagenesis; Mutation; N-terminal; Neoplasm Metastasis; Outcome; Pathogenicity; Patient-Focused Outcomes; Positioning Attribute; Process; Protein Engineering; Proteins; Publishing; RNA; Research; Residual state; Resistance; Resolution; Roentgen Rays; Role; Single-Stranded DNA; Solid; Source; Specificity; Structure; System; Tamoxifen; Testing; Thymine; Uracil; Variant; Vertebral column; Virus; Work; activation-induced cytidine deaminase; analog; apoB mRNA editing catalytic subunit; base; cancer therapy; drug development; ds-DNA; genetic regulatory protein; improved; in vivo; inhibitor; malignant breast neoplasm; member; mouse model; novel; nucleobase; overexpression; preference; prevent; programs; structural biology; therapeutic target; therapy outcome; tumor; tumor heterogeneity

PROJECT 3 – STRUCTURAL BIOLOGY OF DNA DEAMINASES IN BREAST CANCER ABSTRACT The hallmark activity of the APOBEC family of enzymes is deamination of cytosines to uracils (C-to-U) in single-stranded (ss)DNA. This editing activity normally functions in the innate immune response by contributing to virus and transposon restriction. However, recent studies by our labs and many others strongly indicate that APOBEC3B (A3B) is a major source of genomic mutations that drive the progression of multiple human cancers and the development of drug resistance. This finding – that a cellular enzyme actively introduces mutations in cancer – is in stark contrast to a more conventional view, in which mutations in cancer are caused by DNA damage from exogenous sources or errors introduced during DNA replication or repair. Because A3B is not an essential enzyme for life, it is a promising target for anti-cancer therapies. Thus, our Program's overarching hypothesis is that A3B inhibition, as an adjuvant to primary treatment options, will help to prevent detrimental mutation-driven outcomes such as drug resistance and metastasis. However, despite its strong relevance to cancer as a potential therapeutic target, it is not fully known how A3B engages ssDNA substrates, how it achieves high selectivity for ssDNA over RNA, or how its DNA deaminase activity is regulated in cells. Moreover, it is not known how related enzymes such as APOBEC3H (A3H) and APOBEC3F (A3F) with different compositions of ssDNA-binding residues engage similar target sequences. In Project 3, we have started to address these issues by solving multiple A3B catalytic domain crystal structures and, recently, achieving co-crystal structures of ssDNA bound to a variant of the A3B catalytic domain as well as to the related enzyme APOBEC3A (A3A). Aim 1 will build on this knowledge to further delineate the global ssDNA binding mechanism of A3B and A3H. Aim 2 will examine the local dinucleotide targeting mechanism and possible modes of inhibition of the APOBEC family of enzymes. Our goals are to gain deeper mechanistic understandings of the pathogenic APOBEC-mediated ssDNA cytosine deamination process and to establish a solid foundation for future development of APOBEC inhibitors for cancer therapies. These studies will propel our Program toward achieving its long-term goal of inhibiting APOBEC mutagenesis in breast cancer, thereby slowing tumor evolution and improving overall therapeutic outcomes for patients.

项目三：乳腺癌中DNA脱氨酶的结构生物学