Novel functions of Pyruvate kinase M2 in DNA double-strand break repair

丙酮酸激酶M2在DNA双链断裂修复中的新功能

• 批准号: 9130025
• 负责人: ARNAB CHAKRAVARTI
• 金额: $ 40.68万
• 依托单位: UNIV OF ARKANSAS FOR MED SCIS
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-02 至 2019-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9130025
• 关键词: Aftercare; Apoptosis; Brain; Cell Nucleus; Cell Proliferation; Cell Survival; Cells; Clinical; Cytoplasm; DNA Damage; DNA Double Strand Break; Data; Double Strand Break Repair; Enzymes; Excision; Figs - dietary; Genetic; Genetic Models; Glioblastoma; Goals; Health; In Vitro; Ionizing radiation; Laboratories; Malignant Neoplasms; Maps; Mediating; Metabolism; Modeling; Molecular; Neurons; Normal Cell; Nuclear; Pathway interactions; Patients; Phosphorylation; Phosphorylation Site; Poly(ADP-ribose) Polymerases; Predisposition; Protein Kinase; Proteins; Pyruvate Kinase; Radiation; Radiation induced double strand break; Radiation therapy; Radioresistance; Radiosensitization; Regulation; Resistance; Series; Signal Transduction; Testing; Therapeutic Index; Transcription Coactivator; Treatment outcome; Work; ataxia telangiectasia mutated protein; base; biological adaptation to stress; brain cell; brain tissue; cancer cell; cytotoxicity; homologous recombination; improved; in vivo; inhibitor/antagonist; irradiation; neoplastic cell; novel; radiosensitizing; recombinational repair; repaired; research study; response; tumor

DESCRIPTION (provided by applicant): Glioblastoma (GBM) patients only survive an average of 15 months. Tumor resistance to radiation and other forms therapy is the leading challenge in GBM treatment. The mechanisms underlying GBM resistance to radiation therapy (RT) remain poorly understood and agents that selectively sensitize GBM to RT while sparing normal brain tissue are lacking. Pyruvate kinase M2 (PKM2) is the key cytoplasmic glycolytic enzyme, which is critical GBM tumor cell proliferation and expresses highly in cancer cells but minimally in normal brain tissue. Our laboratory has discovered a novel signaling network which connects the nuclear PKM2 function with homologous recombination (HR)-mediated repair of DNA double-strand breaks (DSBs) and GBM tumor cell resistance to radiation-induced cytotoxicity. Furthermore, our preliminary data revealed that PKM2 accumulates in the nucleus following irradiation and interacts with the critical HR rate-limiting protein, CtlP. Meanwhile, ataxia-telangiectasia mutated (ATM), the prime DNA-damage response protein kinase, phosphorylates PKM2 and regulates radiation-induced PKM2 nuclear accumulation and PKM2-depedent HR DSB repair. Therefore, we hypothesize that, in addition to controlling cytosolic glycolytic metabolism, nuclear PKM2 responds to novel upstream regulation by ATM to dictate the fate of irradiated GBM cells by promoting the repair of radiation-induced DSBs through enhanced CtIP-directed HR. A series of in vitro and in vivo experiments are proposed to test our hypotheses: Aim 1 will determine whether CtIP is a critical downstream functional target in PKM2-promotion of HR DSB repair and survival of irradiated GBM cells. Aim 2 will determine how ATM regulates PKM2 in HR DSB repair and subsequent GBM cell survival following radiation treatment. Aim 3 will determine whether targeting nuclear PKM2-dependent HR repair selectively sensitizes GBM tumor cells to DNA damage while sparing noncancerous brain cells in vitro and in vivo.

描述（由申请人提供）： 胶质母细胞瘤 (GBM) 患者平均只能存活 15 个月。肿瘤对放射和其他形式治疗的耐药性是 GBM 治疗的主要挑战。 GBM 对放疗 (RT) 耐药的机制仍知之甚少，并且缺乏选择性地使 GBM 对放疗敏感同时不影响正常脑组织的药物。丙酮酸激酶 M2 (PKM2) 是关键的细胞质糖酵解酶，对 GBM 肿瘤细胞增殖至关重要，在癌细胞中高表达，但在正常脑组织中表达最低。我们的实验室发现了一种新颖的信号网络，它将核 PKM2 功能与同源重组 (HR) 介导的 DNA 双链断裂 (DSB) 修复和 GBM 肿瘤细胞对辐射诱导的细胞毒性的抵抗联系起来。此外，我们的初步数据显示，辐照后 PKM2 在细胞核中积累，并与关键的 HR 限速蛋白 CtlP 相互作用。同时，共济失调毛细血管扩张突变 (ATM)，即主要的 DNA 损伤反应蛋白激酶，磷酸化 PKM2 并调节辐射诱导的 PKM2 核积累和 PKM2 依赖的 HR DSB 修复。因此，我们假设，除了控制胞质糖酵解代谢之外，核 PKM2 还响应 ATM 的新型上游调节，通过增强的 CtIP 定向 HR 促进辐射诱导的 DSB 的修复，从而决定受辐射 GBM 细胞的命运。我们提出了一系列体外和体内实验来检验我们的假设：目标 1 将确定 CtIP 是否是 PKM2 促进 HR DSB 修复和受辐射 GBM 细胞存活的关键下游功能靶点。目标 2 将确定 ATM 如何在 HR DSB 修复和放射治疗后 GBM 细胞存活中调节 PKM2。目标 3 将确定靶向核 PKM2 依赖性 HR 修复是否选择性地使 GBM 肿瘤细胞对 DNA 损伤敏感，同时在体外和体内保护非癌性脑细胞。