The novel role of Sirtuin 2 in regulation of transcription-associated DNA damage repair

项目摘要 辐射和/或顺铂(IR/CISP)诱导的神经元毒性的后果， 也就是说，神经功能缺陷，通常是不可逆转和永久性的，代表着一种令人望而生畏的 在治疗癌症患者时面临挑战。潜在的毒性机制仍然存在 人们对此知之甚少，并有能力有选择地保护神经元存活，同时不损害 缺乏对IR/CISP后肿瘤的控制。这项提案旨在确定机制 保护神经元免受IR/CISP诱导的细胞毒性，首要目标是提供 支持在维持治疗的同时减少其神经毒性的新策略的证据 提高患者的疗效和生活质量。NAD+依赖的脱乙酰酶sirtuin 2(SIRT2)， 它在分化的神经元中高表达，参与多种细胞过程 包括新陈代谢、对氧化应激的反应和肿瘤抑制。我们的初步研究 发现了一种新的信号网络，将SIRT2连接到转录偶联- DNA的同源重组修复(TC-HRR)和核苷酸切除修复(TC-NER IR/CISP诱导的细胞毒性损伤与神经细胞抵抗。此外，我们的数据 研究发现，TC-HR/TC-NER的关键调节因子CSB通过SIRT2直接去乙酰化。 此外，参与DNA损伤信号转导的细胞周期蛋白依赖性激酶5(CDK5)在 神经细胞，磷酸化并抑制SIRT2在DNA修复和神经元存活中的功能 遵循IR/CISP。我们假设SIRT2活性被CDK5介导的抑制 磷酸化，通过增强CSB-1来保护神经元免受IR/CISP诱导的DNA损伤 导向TC-NER和TC-HRR，从而减轻神经元的细胞毒性和神经学 赤字。提出了一系列体外和体内实验来验证这一假说：目标1 将确定CSB是否介导SIRT2促进TC-NER/TC-HRR和神经元存活 遵循IR/CISP。目标2将确定CDK5如何负性调节TC中的SIRT2功能。 NER/TC-HRR与IR/CISP后神经元存活目标3将测试是否有药物靶向 SIRT2特异性地减轻基于IR/CISP的癌症治疗后的神经元缺陷。结果 这些研究将为深入了解SIRT2的生物学作用和分子 IR/CISP所致DNA损伤修复的调控机制我们希望这项研究能为 为未来研究CDK5/SIRT2-CSB信号的靶向性奠定基础 Axis作为一种新的策略来缓解和/或预防癌症患者的神经毒性 IR/CISP治疗。

Project Summary The consequences of irradiation- and/or Cisplatin (IR/CisP)-induced neuronal toxicity, i.e., neurological function deficits, often irreversible and permanent, represent a daunting challenge when treating patients with cancer. The underlying mechanisms of toxicity remain poorly understood and the ability to selectively protect neuronal survival while not compromising tumor control following IR/CisP is lacking. This proposal aims to determine the mechanisms protecting neurons from IR/CisP-induced cytotoxicity, with the overarching goal to provide evidence supporting novel strategies to decrease their neurotoxicity, while maintaining therapy efficacy and improving patient quality of life. NAD+-dependent deacetylase sirtuin 2 (SIRT2), which is highly expressed in differentiated neurons, is involved in diverse cellular processes including metabolism, response to oxidative stress, and tumor suppression. Our preliminary study has discovered a novel signaling network that connects SIRT2 to transcription coupled- homologous recombination repair (TC-HRR) and -nucleotide excision repair (TC-NER) of DNA damage and neuronal cell resistance to IR/CisP-induced cytotoxicity. Furthermore, our data revealed that CSB, the key mediator for TC-HR/TC-NER, is directly deacetylated by SIRT2. Moreover, the cyclin-dependent kinase 5 (CDK5), which is involved in DNA damage signaling in neuron cells, phosphorylates and inhibits SIRT2 function in DNA repair and neuronal survival following IR/CisP. We hypothesize that SIRT2 activity, which is suppressed by CDK5-mediated phosphorylation, protects neurons against IR/CisP-induced DNA damage by enhancing CSB- directed TC-NER and TC-HRR, thereby attenuating neuronal cytotoxicity and neurological deficits. A series of in vitro and in vivo experiments are proposed to test this hypothesis: Aim 1 will determine whether CSB mediates SIRT2 promotion of TC-NER/TC-HRR and neuron survival following IR/CisP. Aim 2 will determine how CDK5 negatively regulates SIRT2 function in TC- NER/TC-HRR and neuron survival following IR/CisP. Aim 3 will test if pharmacologically targeting SIRT2 specifically attenuates neuronal deficits following IR/CisP-based cancer therapy. Results from these studies will provide insights into the biological role of SIRT2 and the molecular mechanisms regulating the repair of IR/CisP-induced DNA damage. We expect this study to lay the foundation for future research investigating the targeting of the CDK5/SIRT2-CSB signaling axis as a novel strategy to alleviate and/or prevent neurotoxicity in cancer patients who need IR/CisP therapy.