DNA-PKcs通过SCF泛素连接酶调控EXO1蛋白稳定性及其DNA同源重组修复中的末端剪切功能机制研究

项目来源

国家自然科学基金(NSFC)

项目主持人

周平坤

项目受资助机构

中国人民解放军军事科学院军事医学研究院

立项年度

2018

立项时间

未公开

项目编号

31870847

研究期限

未知 / 未知

项目级别

国家级

受资助金额

59.00万元

学科

生命科学-生物物理与生物化学-细胞感应与环境生物物理

学科代码

C-C05-C0503

基金类别

面上项目

关键词

电离辐射损伤 ; 损伤修复 ; 信号转导 ; 信号分子 ; 电离辐射修复

参与者

谢达菲;杨陟华;王豫;高山山;郭宗培;李雪萍;刘政;王铎

参与机构

未公开

项目标书摘要:DNA双链断裂(DSB)是放射诱发的严重损伤,真核生物有同源重组(HR)和非同源末端连接(NHEJ)两条主要修复通路。DSB经末端剪切形成一段单链DNA,是启动HR修复的关键,也是修复通路选择的调控点。前期发现,DNA-PKcs失活将导致执行DSB末端剪切的核酸酶EXO1的表达和稳定性显著改变。本课题将深入开展DNA-PKcs调控EXO1泛素化降解的上游信号通路和下游修复功能的研究:明确DNA-PKcs对放射损伤及细胞周期(G1 vs G2)EXO1表达和修饰(泛素化、磷酸化等)的影响规律;探讨SCF E3泛素连接酶对EXO1泛素化的调控机制,重点是DNA-PKcs直接或通过与RBX1的相互作用,对SCF催化核心Cullin-1蛋白的类泛素化修饰及作用于EXO1的活性调控机制;通过观测DSB末端剪切,明确DNA-PKcs通过上述作用对EXO1功能的调控机制,加深对放射生物学机制理论认识。

Application Abstract: DNA double-strand break(DSB)is a severe damage induced by ionizing radiation.There are two major pathways of DSB repairing in eukaryotic cells:homologous recombination(HR)and non-homologous end joining(NHEJ).The yield 3’ssDNA of DSB through the end resection is a key reaction for initiating HR pathway,also a key regulation point for the DSB repair pathway choice.In our previous study,we found the inaction of DNA-PKcs led to a significant decrease of expression and protein stability of the exonuclease EXO1,the critical molecule of executing DSB end resection of HR pathway.Here,this project will further study the upstream signaling pathway and downstream repair function of EXO1 ubiquitination regulated by DNA-PKcs,including:The effects of DNA-PKcs on the alterations of EXO1 ubiquitination and phosphorylation,and the stability after irradiation and in different cell cycle phases;the regulation mechanism of EXO1 ubiquitination by SCF E3 ubiquitin ligase,especially focus on by the direct action and through interaction with RBX1,DNA-PKcs regulates the neddylation of Cullin-1,a component of SCF E3 ubiquitination ligase catalytic core,and its ubiquitin ligase activity on EXO1.Through the observation of DSB end resection reaction,to further elucidate the regulation mechanism of DNA-PKcs on EXO1 repair function.This project will provide further mechanism theory to advance our knowledge on radiation biology.

项目受资助省

北京市

项目结题报告(全文)

DNA双链断裂(DSB)是电离辐射(IR)诱导的最为严重的DNA损伤形式之一,深入研究其精确修复机制,对发展新型放射损伤防护药物、维持基因组的稳定性具有重要意义。DSB的修复通路,主要包括同源重组(HR)修复和非同源末端链接(NHEJ)修复,其中HR修复通路需要同源DNA作为修复模板,仅发生在S/G2期,而G1期细胞只能选择NHEJ修复通路,因此,两者在不同细胞周期的选择和转换对DSB精确修复非常重要。在G1期细胞中,由于缺乏基因组范围内同源DNA(姐妹染色单体DNA尚未合成),因此无法试行和完成HR修复,G1期细胞是如何限制HR修复,确保G1期NHEJ修复顺利进行的机制尚不完全清楚。在DNA双链断裂(DSBs)同源重组修复通路起始阶段,需要进行DSB末端单链切割形成HR修复所必须的末端单链DNA(ssDNA),本研究围绕此过程的关键执行者EXO1的功能调节,以及DNA-PKcs在其中的调控作用展开研究,取得了具有重要理论意义和实践价值的科学发现,主要包括:(1)发现EXO1蛋白在G1期细胞中发生泛素化修饰,由此介导其降解,而在G2期细胞中EXO1蛋白表达较高,以便其执行功能;(2)揭示了RBX1蛋白促进SCF E3泛素连接酶关键组分Cullin 1的类泛素化修饰,促使其介导EXO1蛋白降解;(3)揭示RBX1蛋白促进G1期细胞EXO1泛素化降解对电离辐射损伤具有保护作用;(4)揭示DNA-PKcs激酶在G1细胞的自磷酸化和激酶活性显著高于G2期细胞,由此导致G1期细胞RBX1的高表达。上述科学发现,阐述了一种促进细胞DNA双链断裂修复通路的精确选择的新机制——DNA-PKcs在G1细胞中上调RBX1表达、介导EXO1蛋白泛素化降解,从而限制G1期细胞对DSBs的末端DNA单链切割,避免选择无法完成的HR修复通路,以便于执行非同源末端连接修复通路。本研究的科学发现为深入阐述放射致DNA双链断裂的修复机制提供了科学证据,为发展更有效的放射损伤防护技术奠定理论和实验基础。

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  • 1.Tissue Reactions and Mechanism in Cardiovascular Diseases Induced by Radiation.

    • 关键词:
    • atherosclerosis; cardiovascular diseases; radiation
    • Liu, Xiao-Chang;Zhou, Ping-Kun
    • 《International journal of molecular sciences》
    • 2022年
    • 23卷
    • 23期
    • 期刊

    The long-term survival rate of cancer patients has been increasing as a result of advances in treatments and precise medical management. The evidence has accumulated that the incidence and mortality of non-cancer diseases have increased along with the increase in survival time and long-term survival rate of cancer patients after radiotherapy. The risk of cardiovascular disease as a radiation late effect of tissue damage reactions is becoming a critical challenge and attracts great concern. Epidemiological research and clinical trials have clearly shown the close association between the development of cardiovascular disease in long-term cancer survivors and radiation exposure. Experimental biological data also strongly supports the above statement. Cardiovascular diseases can occur decades post-irradiation, and from initiation and development to illness, there is a complicated process, including direct and indirect damage of endothelial cells by radiation, acute vasculitis with neutrophil invasion, endothelial dysfunction, altered permeability, tissue reactions, capillary-like network loss, and activation of coagulator mechanisms, fibrosis, and atherosclerosis. We summarize the most recent literature on the tissue reactions and mechanisms that contribute to the development of radiation-induced cardiovascular diseases (RICVD) and provide biological knowledge for building preventative strategies.

    ...
  • 2.Downregulation of TAB182 promotes cancer stem-like cell properties and therapeutic resistance in triple-negative breast cancer cells

    • 关键词:
    • TAB182; Cancer stem cells; Cancer stemness property; Therapeuticresistance; Triple-negative breast cancer;PARP INHIBITORS; PATHWAY; OVEREXPRESSION; CISPLATIN; CONTAINS; TNKS1BP1;TRF1; YAP
    • He, Huan;Wang, Shaozheng;Zhang, Wen;Gao, Shanshan;Guan, Hua;Zhou, Pingkun
    • 《BMC CANCER》
    • 2023年
    • 23卷
    • 1期
    • 期刊

    TAB182 participates in DNA damage repair and radio-/chemosensitivity regulation in various tumors, but its role in tumorigenesis and therapeutic resistance in breast cancer remains unclear. In the current paper, we observed that triple-negative Breast Cancer (TNBC), a highly aggressive type of breast cancer, exhibits a lower expression of TAB182. TAB182 knockdown stimulates the proliferation, migration, and invasion of TNBC cells. Our study first obtained RNA-seq data to explore the cellular functions mediated by TAB182 at the genome level in TNBC cells. A transcriptome analysis and in vitro experiments enabled us to identify that TAB182 downregulation drives the enhanced properties of cancer stem-like cells (CSCs) in TNBC cells. Furthermore, TAB182 deletion contributes to the resistance of cells to olaparib or cisplatin, which can be rescued by silencing GLI2, a gene downstream of cancer stemness-related signaling pathways. Our results reveal a novel function of TAB182 as a potential negative regulator of cancer stem-like properties and drug sensitivity in TNBC cells, suggesting that TAB182 may be a tumor suppressor gene and is associated with increased therapeutic benefits for TNBC patients.

    ...
  • 3.Cytosolic Release of Mitochondrial DNA and Associated cGAS Signaling Mediates Radiation-Induced Hematopoietic Injury of Mice.

    • 关键词:
    • bone marrow tissue; cGAS signaling; hematopoietic stem cells; inflammatory response; mice; mitochondrial DNA; non-target effect; radiation injury
    • Guan, Hua;Zhang, Wen;Xie, Dafei;Nie, Yuehua;Chen, Shi;Sun, Xiaoya;Zhao, Hongling;Liu, Xiaochang;Wang, Hua;Huang, Xin;Bai, Chenjun;Huang, Bo;Zhou, Pingkun;Gao, Shanshan
    • 《International journal of molecular sciences》
    • 2023年
    • 24卷
    • 4期
    • 期刊

    Mitochondrion is an important organelle of eukaryotic cells and a critical target of ionizing radiation (IR) outside the nucleus. The biological significance and mechanism of the non-target effect originating from mitochondria have received much attention in the field of radiation biology and protection. In this study, we investigated the effect, role, and radioprotective significance of cytosolic mitochondrial DNA (mtDNA) and its associated cGAS signaling on hematopoietic injury induced by IR in vitro culture cells and in vivo total body irradiated mice in this study. The results demonstrated that gamma-ray exposure increases the release of mtDNA into the cytosol to activate cGAS signaling pathway, and the voltage-dependent anion channel (VDAC) may contribute to IR-induced mtDNA release. VDAC1 inhibitor DIDS and cGAS synthetase inhibitor can alleviate bone marrow injury and ameliorate hematopoietic suppression induced by IR via protecting hematopoietic stem cells and adjusting subtype distribution of bone marrow cells, such as attenuating the increase of the F4/80+ macrophage proportion in bone marrow cells. The present study provides a new mechanistic explanation for the radiation non-target effect and an alternative technical strategy for the prevention and treatment of hematopoietic acute radiation syndrome.

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  • 4.Silencing TAB182 inhibits cell EMT, migration and invasion by downregulating EGFR in A549 NSCLC cells.

    • 关键词:
    • Cell invasion; Cell migration; EGFR; EMT; Lung cancer cells; TAB182
    • Wang, Shaozheng;Guo, Hejiang;Jia, Jin;Zhang, Wen;Gao, Shanshan;Guan, Hua;He, Huan;Zhou, Pingkun
    • 《Molecular biology reports》
    • 2023年
    • 期刊

    BACKGROUND: TAB182 is overexpressed in cancerous tissues and correlated with poor overall survival in lung cancer patients. Mechanistically, TAB182 participates in DNA damage repair and endows tumour cells with radio- and chemoresistance. However, its role in non-small cell lung cancer (NSCLC) remains unclear.; METHODS AND RESULTS: Cells with stable TAB182 knockdown (KD) were generated using A549 NSCLC cells, and we demonstrated that depleting TAB182 inhibits cell EMT, proliferation, colony formation, migration and invasion. Analysis of the TCGA database showed a positive correlation between TAB182 and EGFR, a well-established NSCLC oncoprotein. Then, we verified that silencing TAB182 decreases EGFR expression at both the mRNA and protein levels. Moreover, both TAB182 and EGFR were reported to restore ionizing radiation (IR)-triggered DNA damage. We validated that IR elevates the protein level of EGFR and that silencing TAB182 can alleviate IR-induced EGFR upregulation. Furthermore, overexpressing EGFR abrogates the inhibitory effects of TAB182 KD on EMT, migration, and invasion in A549 cells.; CONCLUSIONS: Our data demonstrated that EGFR expression is regulated by TAB182 and downregulation of TAB182 has a novel function to repress EMT, migration and invasion by decreasing EGFR, indicating TAB182 could regulate the malignant progression of NSCLC. © 2023. The Author(s), under exclusive licence to Springer Nature B.V.

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  • 5.TGF-β1在放射性肺损伤中的促纤维化作用及其机制

    • 关键词:
    • 转化生长因子Β1;放射性肺损伤;放射性肺纤维化;促纤维化
    • 梁鑫鑫;敖兴坤;周圣辉;顾永清
    • 《国际放射医学核医学杂志》
    • 2022年
    • 9期
    • 期刊

    转化生长因子β1(TGF-β1)是一种重要的成纤维细胞因子,其表达水平能反映肺纤维化的严重程度。放射性肺损伤(RILI)包括早期的放射性肺炎(RP)和晚期的放射性肺纤维化(RIPF)。RP向RIPF发展的过程中伴随着TGF-β1表达水平的升高。了解及掌

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  • 6.Transcriptional inhibition of miR-486-3p by BCL6 upregulates Snail and induces epithelial-mesenchymal transition during radiation-induced pulmonary fibrosis

    • 关键词:
    • miR-485-3p; EMT; Snail; BCL6; Radiation-induced pulmonary fibrosis;BREAST-CANCER; GERMINAL CENTER; CELL-PROLIFERATION; RADIOTHERAPY; EMT;DIFFERENTIATION; DEREGULATION; INFLAMMATION; REPRESSION; APOPTOSIS
    • Yan, Ziyan;Ao, Xingkun;Liang, Xinxin;Chen, Zhongmin;Liu, Yuhao;Wang, Ping;Wang, Duo;Liu, Zheng;Liu, Xiaochang;Zhu, Jiaojiao;Zhou, Shenghui;Zhou, Pingkun;Gu, Yongqing
    • 《RESPIRATORY RESEARCH》
    • 2022年
    • 23卷
    • 1期
    • 期刊

    Background Ionizing radiation (IR) can induce pulmonary fibrosis by causing epithelial mesenchymal transition (EMT), but the exact mechanism has not been elucidated. To investigate the molecular mechanism of how radiation induces pulmonary fibrosis by altering miR-486-3p content and thus inducing EMT. Methods The changes of miR-486-3p in cells after irradiation were detected by RT-qPCR. Western blot was used to detect the changes of cellular epithelial marker protein E-cadherin, mesenchymal marker N-cadherin, Vimentin and other proteins. The target gene of miR-486-3p was predicted by bioinformatics method and the binding site was verified by dual luciferase reporter system. In vivo experiments, adeno-associated virus (AAV) was used to carry miR-486-3p mimic to lung. Radiation-induced pulmonary fibrosis (RIPF) model was constructed by 25Gy(60)Co gamma-rays. The structural changes of mouse lung were observed by HE and Masson staining. The expression of relevant proteins in mice was detected by immunohistochemistry. Results IR could decrease the miR-486-3p levels in vitro and in vivo, and that effect was closely correlated to the occurrence of RIPF. The expression of Snail, which induces EMT, was shown to be restrained by miR-486-3p. Therefore, knockdown of Snail blocked the EMT process induced by radiation or knockdown of miR-486-3p. In addition, the molecular mechanism underlying the IR-induced miRNA level reduction was explored. The increased in BCL6 could inhibit the formation of pri-miR-486-3p, thereby reducing the levels of miR-486-3p in the alveolar epithelial cells, which would otherwise promote EMT and contribute to RIPF by targeting Snail. Conclusion IR can exacerbate RIPF in mice by activating the transcription factor BCL6, which inhibits the transcription of miR-486-3p and decreases its content, which in turn increases the content of the target gene slug and triggers EMT.

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  • 7.Radiation-induced non-targeted effect of immunity provoked by mitochondrial DNA damage triggered cGAS/ AIM2 pathways

    • 关键词:
    • Non-targeted;effect;Mitochondrial;DNA;cGAS;Ionizing;radiation;Immune;response;Radiotherapy
    • Wen Zhang;Shi Chen;Hua Guan;Ping-Kun Zhou
    • 《放射医学与防护》
    • 2022年
    • 2期
    • 期刊

    Non-targeted effect is an important complement to the classical target theory of radiation biology which takesnuclear genomic DNA as the core target. The principle of radiation target theory is to assume that an organ

    ...
  • 8.TAB182维持RPA2 mRNA稳定性促进DNA同源重组修复的研究

    • 关键词:
    • TAB182;RPA2;DNA双链断裂;同源重组修复;放射敏感性
    • 李刚;赖淑婷;韩阳;白琛俊;关华;高山山;周平坤
    • 《中华放射医学与防护杂志》
    • 2022年
    • 4期
    • 期刊

    目的探讨TAB182促进同源重组(HR)修复的相关调控分子及机制。方法利用shRNA敲低人乳腺癌MCF-7细胞中的TAB182基因,TAB182敲低的MCF-7细胞为沉默组,使用shRNA阴性对照物的MCF-7细胞为TAB182阴性对照组。通过RNA测序分析,筛选与TAB182相

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  • 9.The Promising Therapeutic Approaches for Radiation-Induced Pulmonary Fibrosis: Targeting Radiation-Induced Mesenchymal Transition of Alveolar Type II Epithelial Cells.

    • 关键词:
    • alveolar type II epithelial cells; epithelial-mesenchymal transition; radiation-induced pulmonary fibrosis
    • Wang, Ping;Yan, Ziyan;Zhou, Ping-Kun;Gu, Yongqing
    • 《International journal of molecular sciences》
    • 2022年
    • 23卷
    • 23期
    • 期刊

    Radiation-induced pulmonary fibrosis (RIPF) is a common consequence of radiation for thoracic tumors, and is accompanied by gradual and irreversible organ failure. This severely reduces the survival rate of cancer patients, due to the serious side effects and lack of clinically effective drugs and methods. Radiation-induced pulmonary fibrosis is a dynamic process involving many complicated and varied mechanisms, of which alveolar type II epithelial (AT2) cells are one of the primary target cells, and the epithelial-mesenchymal transition (EMT) of AT2 cells is very relevant in the clinical search for effective targets. Therefore, this review summarizes several important signaling pathways that can induce EMT in AT2 cells, and searches for molecular targets with potential effects on RIPF among them, in order to provide effective therapeutic tools for the clinical prevention and treatment of RIPF.

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  • 10.LPAR5 confers radioresistance to cancer cells associated with EMT activation via the ERK/Snail pathway

    • 关键词:
    • LPAR5; ERK; Radioresistance; EMT; Radiotherapy;EPITHELIAL-MESENCHYMAL TRANSITION; SIGNALING PATHWAY; PROMOTESRADIORESISTANCE; LUNG-CANCER; TUMOR-CELLS; RECEPTOR; INVASION;EXPRESSION; RESISTANCE; RADIOTHERAPY
    • Sun, Xiao-Ya;Li, Hao-Zheng;Xie, Da-Fei;Gao, Shan-Shan;Huang, Xin;Guan, Hua;Bai, Chen-Jun;Zhou, Ping-Kun
    • 《JOURNAL OF TRANSLATIONAL MEDICINE》
    • 2022年
    • 20卷
    • 1期
    • 期刊

    Background: Epithelial-to-mesenchymal transition (EMT) is a critical event contributing to more aggressive phenotypes in cancer cells. EMT is frequently activated in radiation-targeted cells during the course of radiotherapy, which often endows cancers with acquired radioresistance. However, the upstream molecules driving the signaling pathways of radiation-induced EMT have not been fully delineated.Methods: In this study, RNA-seq-based transcriptome analysis was performed to identify the early responsive genes of HeLa cells to gamma-ray irradiation. EMT-associated genes were knocked down by siRNA technology or overexpressed in HeLa cells and A549 cells, and the resulting changes in phenotypes of EMT and radiosensitivity were assessed using qPCR and Western blotting analyses, migration assays, colony-forming ability and apoptosis of flow cytometer assays.Results: Through RNA-seq-based transcriptome analysis, we found that LPAR5 is downregulated in the early response of HeLa cells to gamma-ray irradiation. Radiation-induced alterations in LPAR5 expression were further revealed to be a bidirectional dynamic process in HeLa and A549 cells, i.e., the early downregulating phase at 2 similar to 4 h and the late upregulating phase at 24 h post-irradiation. Overexpression of LPAR5 prompts EMT programing and migration of cancer cells. Moreover, increased expression of LPAR5 is significantly associated with IR-induced EMT and confers radioresistance to cancer cells. Knockdown of LPAR5 suppressed IR-induced EMT by attenuating the activation of ERK signaling and downstream Snail, MMP1, and MMP9 expression.Conclusions: LPAR5 is an important upstream regulator of IR-induced EMT that modulates the ERK/Snail pathway. This study provides further insights into understanding the mechanism of radiation-induced EMT and identifies promising targets for improving the effectiveness of cancer radiation therapy.

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