Mechanisms of SIRT2 Function in the DNA Damage Response

SIRT2 在 DNA 损伤反应中的作用机制

• 批准号: 9978732
• 负责人: David Sung-wen Yu
• 金额: $ 35.1万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9978732
• 关键词: Acetylation; Adjuvant; Aging; Antineoplastic Agents; Binding; Biochemical; Biological; Breast; Breast Cancer Cell; Breast Cancer Patient; Breast Cancer Treatment; Cancer Control; Cell physiology; Cells; Cellular Metabolic Process; Clinical; Consumption; DNA; DNA Damage; DNA Double Strand Break; DNA Repair; Data; Deacetylase; Deacetylation; Deubiquitination; Development; Double Strand Break Repair; Enzymes; Event; Excision; Family; Funding; Genetic; Genetic Recombination; Genomic Instability; Homeostasis; Human; Impairment; In Vitro; Ionizing radiation; Link; Liver; Lysine; Malignant Neoplasms; Mediating; Metabolic; Metabolism; Molecular Target; Monoubiquitination; Mus; Mutation; Patient-Focused Outcomes; Patients; Play; Poly(ADP-ribose) Polymerases; Post-Translational Protein Processing; Production; Proteins; Proteomics; Regulation; Resistance; Role; Signal Transduction; Sirtuins; Site; TREX1 gene; Testing; Treatment Efficacy; Tumor Suppressor Proteins; Ubiquitination; Work; Xenograft procedure; base; biological adaptation to stress; breast malignancies; cancer cell; cancer therapy; cancer type; carcinogenesis; chemotherapy; conventional therapy; genetic regulatory protein; genome integrity; homologous recombination; improved; in vivo; inhibitor/antagonist; innovation; insight; malignant breast neoplasm; member; mouse model; neoplastic cell; novel; novel therapeutic intervention; nuclease; overexpression; prevent; radiation resistance; recombinational repair; repaired; replication stress; response; response biomarker; therapy resistant; treatment strategy; tumor

PROJECT SUMMARY The objective of this proposal is to define the critical role that SIRT2 plays in directing the DNA damage response (DDR) through post-translational modification of the acetylome, which places it at the confluence of cellular metabolism, aging, carcinogenesis, and development of tumor cell resistance to anticancer agents. SIRT2 is a sirtuin family deacetylase that sense energy requirements and direct cellular processes to maintain metabolic homeostasis. Significantly, mice deficient in Sirt2 develop breast, liver, and other cancers, implying that SIRT2 is a tumor suppressor. Paradoxically, SIRT2 is overexpressed in many human cancers, including breast malignancies, and furthermore, our data suggest that high SIRT2 expression is associated with poor survival in breast cancer patients treated with adjuvant ionizing radiation (IR) and contributes to resistance to many types of cancer treatments, including IR, PARP inhibitor, and chemotherapy. However, the precise mechanisms by which SIRT2 directs the DDR to govern tumor cell treatment resistance, and moreover, how SIRT2 itself is regulated in the DDR are poorly understood. In the previous funding period, we defined a novel role for SIRT2 in directing the replication stress response (RSR) through the acetylation status of ATRIP and CDK9, and furthermore, showed that somatic SIRT2 mutations impair the activity of SIRT2 in maintaining genome integrity. In this renewal application, we propose to carry this work further by investigating a new role for SIRT2 in directing the repair of DNA double-strand breaks (DSB) through deacetylation of MRE11, identifying the upstream ubiquitination signaling events governing SIRT2 activity, and determining if SIRT2 inhibition is an effective therapeutic strategy for treatment of breast cancers resistant to conventional therapies. In this regard, we have shown that SIRT2 deacetylase activity mediates resistance of cancer cells to IR and PARP inhibitor by facilitating the end resection step in homologous recombination repair. We further identified a novel network of DDR proteins deacetylated by SIRT2 in response to IR, including MRE11. Moreover, our data suggest that SIRT2 activity but not levels is regulated in the DDR via protein monoubiquitination. We hypothesize that SIRT2 responds to upstream ubiquitination signaling to maintain genome integrity and govern breast cancer treatment resistance by directing the DDR through deacetylation of key substrates, including MRE11, which may be exploited to improve breast cancer control. We propose to: 1) Determine the role of SIRT2 in directing MRE11 in the DDR; 2) Dissect the mechanism by which SIRT2 is regulated by monoubiquitination in the DDR; 3) Establish SIRT2 as a new molecular target for breast cancer resistant to DNA damaging agents. Completion of this work will provide a detailed mechanistic understanding of how SIRT2 directs DSB repair to maintain genome integrity and govern tumor cell treatment resistance, define a novel mechanism for regulation of SIRT2 via protein monoubiquitination in the DDR, and establish proof of concept for SIRT2 inhibition as novel therapeutic approach for overcoming breast cancer treatment resistance.

项目概要 该提案的目的是确定 SIRT2 在引导 DNA 损伤中发挥的关键作用 通过乙酰基组的翻译后修饰，将其置于 细胞代谢、衰老、癌变以及肿瘤细胞对抗癌药物耐药性的发展。 SIRT2 是一种沉默调节蛋白家族脱乙酰酶，可感知能量需求并指导细胞过程以维持 代谢稳态。值得注意的是，缺乏 Sirt2 的小鼠会患上乳腺癌、肝癌和其他癌症，这意味着 SIRT2 是一种肿瘤抑制因子。矛盾的是，SIRT2 在许多人类癌症中过度表达，包括 此外，我们的数据表明，SIRT2 高表达与乳腺恶性肿瘤的不良预后相关。 接受辅助电离辐射 (IR) 治疗的乳腺癌患者的生存率，并有助于抵抗 许多类型的癌症治疗，包括 IR、PARP 抑制剂和化疗。然而，准确的 SIRT2 指导 DDR 控制肿瘤细胞治疗耐药性的机制，以及如何 SIRT2 本身在 DDR 中的调节还知之甚少。在之前的资助期间，我们定义了一个小说 SIRT2 通过 ATRIP 的乙酰化状态指导复制应激反应 (RSR) 的作用 此外，CDK9 还表明体细胞 SIRT2 突变会损害 SIRT2 在维持 基因组完整性。在此更新申请中，我们建议通过调查新角色来进一步开展这项工作 SIRT2 通过 MRE11 去乙酰化来指导 DNA 双链断裂 (DSB) 的修复， 识别控制 SIRT2 活性的上游泛素化信号事件，并确定 SIRT2 是否 抑制是治疗对常规疗法耐药的乳腺癌的有效治疗策略。 在这方面，我们已经证明 SIRT2 脱乙酰酶活性介导癌细胞对 IR 和 PARP 抑制剂通过促进同源重组修复中的末端切除步骤。我们进一步确定 SIRT2 响应 IR 脱乙酰化的新型 DDR 蛋白网络，包括 MRE11。此外，我们的 数据表明，SIRT2 活性而非水平在 DDR 中通过蛋白质单泛素化进行调节。我们 假设 SIRT2 响应上游泛素化信号以维持基因组完整性并控制 通过关键底物的脱乙酰作用来指导 DDR，从而消除乳腺癌治疗耐药性，包括 MRE11，可用于改善乳腺癌控制。我们建议： 1) 确定角色 SIRT2 指导 DDR 中的 MRE11； 2）剖析SIRT2的调控机制 DDR 中的单泛素化； 3）建立SIRT2作为乳腺癌耐药的新分子靶点 DNA 损伤剂。完成这项工作将提供对如何进行详细的机制理解 SIRT2 指导 DSB 修复以维持基因组完整性并控制肿瘤细胞治疗耐药性，定义了 通过 DDR 中的蛋白质单泛素化调节 SIRT2 的新机制，并建立了以下证据： SIRT2 抑制作为克服乳腺癌治疗耐药性的新治疗方法的概念。