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Wang FC, Peng B, Ren TT, Liu SP, Du JR, Chen ZH, Zhang TT, Gu X, Li M, Cao SL, Xu X. A 1,2,3-Triazole Derivative of Quinazoline Exhibits Antitumor Activity by Tethering RNF168 to SQSTM1/P62. J Med Chem 2022; 65:15028-15047. [DOI: 10.1021/acs.jmedchem.2c00432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Fu-Cheng Wang
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, International Cancer Center, and Marshall Laboratory of Biomedical Engineering, Shenzhen University School of Medicine, Shenzhen, Guangdong 518060, PR China
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, School of Biomedical Engineering, Health Science Center, Shenzhen University, Shenzhen, Guangdong 518060, PR China
| | - Bin Peng
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, International Cancer Center, and Marshall Laboratory of Biomedical Engineering, Shenzhen University School of Medicine, Shenzhen, Guangdong 518060, PR China
| | - Ting-Ting Ren
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Shao-Peng Liu
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Jing-Rui Du
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Zi-Hao Chen
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Ting-Ting Zhang
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Xiaoyang Gu
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 10091, PR China
| | - Mo Li
- Center for Reproductive Medicine, Department of Obstetrics and Gynecology, Peking University Third Hospital, Beijing 10091, PR China
| | - Sheng-Li Cao
- Department of Chemistry, Capital Normal University, Beijing, 100048, PR China
| | - Xingzhi Xu
- Guangdong Key Laboratory for Genome Stability & Disease Prevention, International Cancer Center, and Marshall Laboratory of Biomedical Engineering, Shenzhen University School of Medicine, Shenzhen, Guangdong 518060, PR China
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Maleki Dana P, Sadoughi F, Mirzaei H, Asemi Z, Yousefi B. DNA damage response and repair in the development and treatment of brain tumors. Eur J Pharmacol 2022; 924:174957. [DOI: 10.1016/j.ejphar.2022.174957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 04/03/2022] [Accepted: 04/11/2022] [Indexed: 11/03/2022]
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Vicar T, Gumulec J, Kolar R, Kopecna O, Pagacova E, Falkova I, Falk M. DeepFoci: Deep learning-based algorithm for fast automatic analysis of DNA double-strand break ionizing radiation-induced foci. Comput Struct Biotechnol J 2022; 19:6465-6480. [PMID: 34976305 PMCID: PMC8668444 DOI: 10.1016/j.csbj.2021.11.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/11/2021] [Accepted: 11/14/2021] [Indexed: 11/26/2022] Open
Abstract
DNA double-strand breaks (DSBs), marked by ionizing radiation-induced (repair) foci (IRIFs), are the most serious DNA lesions and are dangerous to human health. IRIF quantification based on confocal microscopy represents the most sensitive and gold-standard method in radiation biodosimetry and allows research on DSB induction and repair at the molecular and single-cell levels. In this study, we introduce DeepFoci - a deep learning-based fully automatic method for IRIF counting and morphometric analysis. DeepFoci is designed to work with 3D multichannel data (trained for 53BP1 and γH2AX) and uses U-Net for nucleus segmentation and IRIF detection, together with maximally stable extremal region-based IRIF segmentation. The proposed method was trained and tested on challenging datasets consisting of mixtures of nonirradiated and irradiated cells of different types and IRIF characteristics - permanent cell lines (NHDFs, U-87) and primary cell cultures prepared from tumors and adjacent normal tissues of head and neck cancer patients. The cells were dosed with 0.5-8 Gy γ-rays and fixed at multiple (0-24 h) postirradiation times. Under all circumstances, DeepFoci quantified the number of IRIFs with the highest accuracy among current advanced algorithms. Moreover, while the detection error of DeepFoci remained comparable to the variability between two experienced experts, the software maintained its sensitivity and fidelity across dramatically different IRIF counts per nucleus. In addition, information was extracted on IRIF 3D morphometric features and repair protein colocalization within IRIFs. This approach allowed multiparameter IRIF categorization of single- or multichannel data, thereby refining the analysis of DSB repair processes and classification of patient tumors, with the potential to identify specific cell subclones. The developed software improves IRIF quantification for various practical applications (radiotherapy monitoring, biodosimetry, etc.) and opens the door to advanced DSB focus analysis and, in turn, a better understanding of (radiation-induced) DNA damage and repair.
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Key Words
- 53BP1, P53-binding protein 1
- Biodosimetry
- CNN, convolutional neural network
- Confocal Microscopy
- Convolutional Neural Network
- DNA Damage and Repair
- DSB, DNA double-strand break
- Deep Learning
- FOV, field of view
- GUI, graphical user interface
- IRIF, ionizing radiation-induced (repair) foci
- Image Analysis
- Ionizing Radiation-Induced Foci (IRIFs)
- MSER, maximally stable extremal region (algorithm)
- Morphometry
- NHDFs, normal human dermal fibroblasts
- RAD51, DNA repair protein RAD51 homolog 1
- U-87, U-87 glioblastoma cell line
- γH2AX, histone H2AX phosphorylated at serine 139
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Affiliation(s)
- Tomas Vicar
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 3058/10, Brno, Czech Republic.,Czech Academy of Sciences, Institute of Biophysics, v.v.i, Department of Cell Biology and Radiobiology, Kralovopolska 135, Brno, Czech Republic.,Department of Pathological Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, Brno, Czech Republic
| | - Jaromir Gumulec
- Department of Pathological Physiology, Faculty of Medicine, Masaryk University, Kamenice 5, Brno, Czech Republic
| | - Radim Kolar
- Department of Biomedical Engineering, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technicka 3058/10, Brno, Czech Republic
| | - Olga Kopecna
- Czech Academy of Sciences, Institute of Biophysics, v.v.i, Department of Cell Biology and Radiobiology, Kralovopolska 135, Brno, Czech Republic
| | - Eva Pagacova
- Czech Academy of Sciences, Institute of Biophysics, v.v.i, Department of Cell Biology and Radiobiology, Kralovopolska 135, Brno, Czech Republic
| | - Iva Falkova
- Czech Academy of Sciences, Institute of Biophysics, v.v.i, Department of Cell Biology and Radiobiology, Kralovopolska 135, Brno, Czech Republic
| | - Martin Falk
- Czech Academy of Sciences, Institute of Biophysics, v.v.i, Department of Cell Biology and Radiobiology, Kralovopolska 135, Brno, Czech Republic
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Tatin X, Muggiolu G, Sauvaigo S, Breton J. Evaluation of DNA double-strand break repair capacity in human cells: Critical overview of current functional methods. MUTATION RESEARCH. REVIEWS IN MUTATION RESEARCH 2021; 788:108388. [PMID: 34893153 DOI: 10.1016/j.mrrev.2021.108388] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 06/17/2021] [Accepted: 06/23/2021] [Indexed: 02/05/2023]
Abstract
DNA double-strand breaks (DSBs) are highly deleterious lesions, responsible for mutagenesis, chromosomal translocation or cell death. DSB repair (DSBR) is therefore a critical part of the DNA damage response (DDR) to restore molecular and genomic integrity. In humans, this process is achieved through different pathways with various outcomes. The balance between DSB repair activities varies depending on cell types, tissues or individuals. Over the years, several methods have been developed to study variations in DSBR capacity. Here, we mainly focus on functional techniques, which provide dynamic information regarding global DSB repair proficiency or the activity of specific pathways. These methods rely on two kinds of approaches. Indirect techniques, such as pulse field gel electrophoresis (PFGE), the comet assay and immunofluorescence (IF), measure DSB repair capacity by quantifying the time-dependent decrease in DSB levels after exposure to a DNA-damaging agent. On the other hand, cell-free assays and reporter-based methods directly track the repair of an artificial DNA substrate. Each approach has intrinsic advantages and limitations and despite considerable efforts, there is currently no ideal method to quantify DSBR capacity. All techniques provide different information and can be regarded as complementary, but some studies report conflicting results. Parameters such as the type of biological material, the required equipment or the cost of analysis may also limit available options. Improving currently available methods measuring DSBR capacity would be a major step forward and we present direct applications in mechanistic studies, drug development, human biomonitoring and personalized medicine, where DSBR analysis may improve the identification of patients eligible for chemo- and radiotherapy.
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Affiliation(s)
- Xavier Tatin
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, SyMMES, 38000 Grenoble, France; LXRepair, 5 Avenue du Grand Sablon, 38700 La Tronche, France
| | | | - Sylvie Sauvaigo
- LXRepair, 5 Avenue du Grand Sablon, 38700 La Tronche, France
| | - Jean Breton
- Univ. Grenoble Alpes, CEA, CNRS, IRIG, SyMMES, 38000 Grenoble, France.
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Sak A, Bannik K, Groneberg M, Stuschke M. Chaetocin induced chromatin condensation: effect on DNA repair signaling and survival. Int J Radiat Biol 2021; 97:494-506. [PMID: 33428851 DOI: 10.1080/09553002.2021.1872813] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 12/07/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022]
Abstract
PURPOSE The aim of the present study was to evaluate the effect of the histone lysine-methyltransferase (HKMT) inhibitor chaetocin on chromatin structure and its effect on ionizing radiation (IR) induced DNA damage response. METHODS Concentration and time-dependent effects of chaetocin on chromatin clustering and its reversibility were analyzed by immunofluorescent assays in the non-small cell lung carcinoma (NSCLC) cell lines H460 and H1299Q4 and in human skin fibroblasts. In addition, IR induced damage response (γH2AX, 53BP1, and pATM foci formation) was studied by immunofluorescent assays. The effect on survival was determined by performing single-cell clonogenic assays. RESULTS Chaetocin significantly increased the radiation sensitivity of H460 (F test on nonlinear regression, p < .0011) and of H1299 (p = .0201). In addition, treatment with 15 nM chaetocin also decreased the total radiation doses that control 50% of the plaque monolayers (TCD50) from 17.2 ± 0.3 Gy to 7.3 ± 0.4 Gy (p < .0001) in H1299 cells and from 11.6 ± 0.1 Gy to 6.5 ± 0.3 Gy (p < .0001). Phenotypically, chaetocin led to a time and concentration-dependent clustering of the chromatin in H1299 as well as in fibroblasts, but not in H460 cells. This phenotype of chaetocin induced chromatin clustering (CICC) was reversible and depended on the expression of the HKMTs SUV39H1 and G9a. Treatment with siRNA for SUV39h1 and G9a significantly reduced the CICC phenotype. Immunofluorescent assay results showed that the CICC phenotype was enriched for the heterochromatic marker proteins H3K9me3 and HP1α. γH2AX foci formation was not affected, neither in cells with normal nor with CICC phenotype. In contrast, repair signaling with 53BP1 and pATM foci formation was significantly reduced in the CICC phenotype. CONCLUSIONS Treatment with chaetocin increased the radiation sensitivity of cells in vitro and DNA damage response, especially of 53BP1 and ATM-dependent repair by affecting chromatin structure. The obtained results support the potential use of natural HKMT inhibitors such as chaetocin or other bioactive compounds in improving radiosensitivity of cancer cells.
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Affiliation(s)
- A Sak
- Department of Radiotherapy, Universitätsklinikum Essen, Essen, Germany
| | - K Bannik
- Department of Radiotherapy, Universitätsklinikum Essen, Essen, Germany
| | - M Groneberg
- Department of Radiotherapy, Universitätsklinikum Essen, Essen, Germany
| | - M Stuschke
- Department of Radiotherapy, Universitätsklinikum Essen, Essen, Germany
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Wikiniyadhanee R, Lerksuthirat T, Stitchantrakul W, Chitphuk S, Sura T, Dejsuphong D. TRIM29 is required for efficient recruitment of 53BP1 in response to DNA double-strand breaks in vertebrate cells. FEBS Open Bio 2020; 10:2055-2071. [PMID: 33017104 PMCID: PMC7530400 DOI: 10.1002/2211-5463.12954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 07/18/2020] [Accepted: 08/14/2020] [Indexed: 12/17/2022] Open
Abstract
Tripartite motif‐containing protein 29 (TRIM29) is involved in DNA double‐strand break (DSB) repair. However, the specific roles of TRIM29 in DNA repair are not clearly understood. To investigate the involvement of TRIM29 in DNA DSB repair, we disrupted TRIM29 in DT40 cells by gene targeting with homologous recombination (HR). The roles of TRIM29 were investigated by clonogenic survival assays and immunofluorescence analyses. TRIM29 triallelic knockout (TRIM29−/−/−/+) cells were sensitive to etoposide, but resistant to camptothecin. Foci formation assays to assess DNA repair activities showed that the dissociation of etoposide‐induced phosphorylated H2A histone family member X (ɣ‐H2AX) foci was retained in TRIM29−/−/−/+ cells, and the formation of etoposide‐induced tumor suppressor p53‐binding protein 1 (53BP1) foci in TRIM29−/−/−/+ cells was slower compared with wild‐type (WT) cells. Interestingly, the kinetics of camptothecin‐induced RAD51 foci formation of TRIM29−/−/−/+ cells was higher than that of WT cells. These results indicate that TRIM29 is required for efficient recruitment of 53BP1 to facilitate the nonhomologous end‐joining (NHEJ) pathway and thereby suppress the HR pathway in response to DNA DSBs. TRIM29 regulates the choice of DNA DSB repair pathway by facilitating 53BP1 accumulation to promote NHEJ and may have potential for development into a therapeutic target to sensitize refractory cancers or as biomarker of personalized therapies.
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Affiliation(s)
- Rakkreat Wikiniyadhanee
- Section for Translational Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Tassanee Lerksuthirat
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Wasana Stitchantrakul
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Sermsiri Chitphuk
- Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Thanyachai Sura
- Department of Internal Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Donniphat Dejsuphong
- Section for Translational Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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El-Shafie S, Fahmy SA, Ziko L, Elzahed N, Shoeib T, Kakarougkas A. Encapsulation of Nedaplatin in Novel PEGylated Liposomes Increases Its Cytotoxicity and Genotoxicity against A549 and U2OS Human Cancer Cells. Pharmaceutics 2020; 12:pharmaceutics12090863. [PMID: 32927897 PMCID: PMC7559812 DOI: 10.3390/pharmaceutics12090863] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 08/24/2020] [Accepted: 08/25/2020] [Indexed: 12/28/2022] Open
Abstract
Following the discovery of cisplatin over 50 years ago, platinum-based drugs have been a widely used and effective form of cancer therapy, primarily causing cell death by inducing DNA damage and triggering apoptosis. However, the dose-limiting toxicity of these drugs has led to the development of second and third generation platinum-based drugs that maintain the cytotoxicity of cisplatin but have a more acceptable side-effect profile. In addition to the creation of new analogs, tumor delivery systems such as liposome encapsulated platinum drugs have been developed and are currently in clinical trials. In this study, we have created the first PEGylated liposomal form of nedaplatin using thin film hydration. Nedaplatin, the main focus of this study, has been exclusively used in Japan for the treatment of non-small cell lung cancer, head and neck, esophageal, bladder, ovarian and cervical cancer. Here, we investigate the cytotoxic and genotoxic effects of free and liposomal nedaplatin on the human non-small cell lung cancer cell line A549 and human osteosarcoma cell line U2OS. We use a variety of assays including ICP MS and the highly sensitive histone H2AX assay to assess drug internalization and to quantify DNA damage induction. Strikingly, we show that by encapsulating nedaplatin in PEGylated liposomes, the platinum uptake cytotoxicity and genotoxicity of nedaplatin was significantly enhanced in both cancer cell lines. Moreover, the enhanced platinum uptake as well as the cytotoxic/antiproliferative effect of liposomal nedaplatin appears to be selective to cancer cells as it was not observed on two noncancer cell lines. This is the first study to develop PEGylated liposomal nedaplatin and to demonstrate the superior cell delivery potential of this product.
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Affiliation(s)
- Salma El-Shafie
- Department of Biology, School of Sciences and Engineering, The American University in Cairo, Cairo 11835, Egypt; (S.E.-S.); (L.Z.); (N.E.)
| | - Sherif Ashraf Fahmy
- Department of Chemistry, School of Sciences and Engineering, The American University in Cairo, Cairo 11835 Egypt;
| | - Laila Ziko
- Department of Biology, School of Sciences and Engineering, The American University in Cairo, Cairo 11835, Egypt; (S.E.-S.); (L.Z.); (N.E.)
| | - Nada Elzahed
- Department of Biology, School of Sciences and Engineering, The American University in Cairo, Cairo 11835, Egypt; (S.E.-S.); (L.Z.); (N.E.)
| | - Tamer Shoeib
- Department of Chemistry, School of Sciences and Engineering, The American University in Cairo, Cairo 11835 Egypt;
- Correspondence: (T.S.); (A.K.)
| | - Andreas Kakarougkas
- Department of Biology, School of Sciences and Engineering, The American University in Cairo, Cairo 11835, Egypt; (S.E.-S.); (L.Z.); (N.E.)
- Correspondence: (T.S.); (A.K.)
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Xu SJ, Wang X, Wang TY, Lin ZZ, Hu YJ, Huang ZL, Yang XJ, Xu P. Flavonoids from Rosaroxburghii Tratt prevent reactive oxygen species-mediated DNA damage in thymus cells both combined with and without PARP-1 expression after exposure to radiation in vivo. Aging (Albany NY) 2020; 12:16368-16389. [PMID: 32862153 PMCID: PMC7485694 DOI: 10.18632/aging.103688] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 06/13/2020] [Indexed: 11/25/2022]
Abstract
This study aimed to evaluate the role of FRT in ROS/DNA regulation with or without PARP-1 in radiation-injured thymus cells. The administration of FRT to PARP-1-/- (KO) mice demonstrated that FRT significantly increased the viability of thymus cells and decreased their rate of apoptosis through PARP-1. Radiation increased the levels of ROS, γ-H2AX and 53BP1, and induced DNA double strand breaks. Compared with wild type (WT) mice, levels of ROS, γ-H2AX and 53BP1 in KO mice were much less elevated. The FRT treatment groups also showed little reduction in these indicators in KO mice compared with WT mice. The results of the KO mice study indicated that FRT reduced ROS activation through inhibition of PARP-1. Furthermore, FRT reduced the concentrations of γ-H2AX by decreasing ROS activation. However, we found that FRT did not regulate 53BP1, a marker of DNA damage, because of its elimination of ROS. Levels of apoptosis-inducing factor (AIF), exhibited no significant difference after irradiation in KO mice. To summarize, ROS suppression by PARP-1 knockout in KO mice highlights potential therapeutic target either by PARP-1 inhibition combined with radiation or by treatment with a drug therapy alone. AIF-induced apoptosis could not be activated in KO mice.
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Affiliation(s)
- Sai-Juan Xu
- Department of Pharmacy, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Xia Wang
- College of Medical Laboratory, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Tao-Yang Wang
- Henan Key Laboratory of Medical Tissue Regeneration, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Zheng-Zhan Lin
- Department of Pharmacy, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Yong-Jian Hu
- Henan Key Laboratory of Medical Tissue Regeneration, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Zhong-Lin Huang
- Henan Key Laboratory of Medical Tissue Regeneration, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Xian-Jun Yang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang 453003, Henan, China
| | - Ping Xu
- Henan Key Laboratory of Medical Tissue Regeneration, Xinxiang Medical University, Xinxiang 453003, Henan, China
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Maraldi T, Prata C, Marrazzo P, Hrelia S, Angeloni C. Natural Compounds as a Strategy to Optimize " In Vitro" Expansion of Stem Cells. Rejuvenation Res 2019; 23:93-106. [PMID: 31368407 DOI: 10.1089/rej.2019.2187] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The efficient use of stem cells for transplantation is often limited by the relatively low number of stem cells collected. The ex vivo expansion of human stem cells for clinical use is a potentially valuable approach to increase stem cell number. Currently, most of the procedures used to expand stem cells are carried out using a 21% oxygen concentration, which is about 4- to 10-fold greater than the concentration characteristic of their natural niches. Hyperoxia might cause oxidative stress with a deleterious effect on the physiology of cultured stem cells. In this review, we investigate and critically examine the available information on the ability of natural compounds to counteract hyperoxia-induced damage in different types of stem cells ex vivo. In particular, we focused on proliferation and stemness maintenance in an attempt to draw up useful indications to define new culture media with a promoting activity on cell expansion in vitro.
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Affiliation(s)
- Tullia Maraldi
- Department of Surgery, Medicine, Dentistry and Morphological Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Cecilia Prata
- Department of Pharmacy and Biotechnology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Pasquale Marrazzo
- Department for Life Quality Studies, Alma Mater Studiorum-University of Bologna, Rimini, Italy
| | - Silvana Hrelia
- Department for Life Quality Studies, Alma Mater Studiorum-University of Bologna, Rimini, Italy
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10
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Singh P, Aggarwal LM, Parry SA, Raman MJ. Radiation dosimetry and repair kinetics of DNA damage foci in mouse pachytene spermatocyte and round spermatid stages. Mutagenesis 2019; 33:231-239. [PMID: 30239864 DOI: 10.1093/mutage/gey007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 04/19/2018] [Indexed: 12/23/2022] Open
Abstract
Accurate quantification of DNA double strand breaks (DSB) in testicular germ cells is difficult because of cellular heterogeneity and the presence of endogenous γH2AX. Here, we used confocal microscopy to quantify DNA damage and repair kinetics following γ-irradiation (0.5-4 Gy) in three major mouse male germ cell stages, early and late pachytene spermatocytes and round spermatids (RSs), following a defined post irradiation time course. Dose-response curves showing linear best fit validated γH2AX focus as a rapid biodosimetric tool in these substages in response to whole body in vivo exposure. Stage specific foci yield/dose and repair kinetics demonstrated differential radiosensitivity and repair efficiency: early pachytenes (EP) repaired most rapidly and completely followed by late pachytene (LP) and RSs. Repair kinetics for all three stages followed 'exponential decay' in response to each radiation dose. In pachytenes immediate colocalisation of γH2AX and 53BP1, which participates in non-homologous end-joining repair pathway, was followed by dissociation from the major focal area of γH2AX by 4 h demonstrating ongoing DSB repair. These results confirm the differential radiosensitivity and repair kinetics of DSBs in male germ cells at different stages. Taken together, our results provide a simple and accurate method for assessing DNA damage and repair kinetics during spermatogenesis.
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Affiliation(s)
- Priti Singh
- Cytogenetics Laboratory, Department of Zoology, Centre of Advanced Study, India
| | - Lalit Mohan Aggarwal
- Department of Radiotherapy and Radiation Medicine, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India
| | - Stephen A Parry
- Cornell Statistical Consulting Unit, Cornell University, Ithaca, NY, USA
| | - Mercy J Raman
- Cytogenetics Laboratory, Department of Zoology, Centre of Advanced Study, India
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Sheppard EC, Morrish RB, Dillon MJ, Leyland R, Chahwan R. Epigenomic Modifications Mediating Antibody Maturation. Front Immunol 2018. [PMID: 29535729 PMCID: PMC5834911 DOI: 10.3389/fimmu.2018.00355] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Epigenetic modifications, such as histone modifications, DNA methylation status, and non-coding RNAs (ncRNA), all contribute to antibody maturation during somatic hypermutation (SHM) and class-switch recombination (CSR). Histone modifications alter the chromatin landscape and, together with DNA primary and tertiary structures, they help recruit Activation-Induced Cytidine Deaminase (AID) to the immunoglobulin (Ig) locus. AID is a potent DNA mutator, which catalyzes cytosine-to-uracil deamination on single-stranded DNA to create U:G mismatches. It has been shown that alternate chromatin modifications, in concert with ncRNAs and potentially DNA methylation, regulate AID recruitment and stabilize DNA repair factors. We, hereby, assess the combination of these distinct modifications and discuss how they contribute to initiating differential DNA repair pathways at the Ig locus, which ultimately leads to enhanced antibody–antigen binding affinity (SHM) or antibody isotype switching (CSR). We will also highlight how misregulation of epigenomic regulation during DNA repair can compromise antibody development and lead to a number of immunological syndromes and cancer.
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Affiliation(s)
- Emily C Sheppard
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | | | - Michael J Dillon
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
| | | | - Richard Chahwan
- Living Systems Institute, University of Exeter, Exeter, United Kingdom
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12
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Effects of Antioxidant Supplements on the Survival and Differentiation of Stem Cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:5032102. [PMID: 28770021 PMCID: PMC5523230 DOI: 10.1155/2017/5032102] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 05/31/2017] [Indexed: 12/13/2022]
Abstract
Although physiological levels of reactive oxygen species (ROS) are required to maintain the self-renewal capacity of stem cells, elevated ROS levels can induce chromosomal aberrations, mitochondrial DNA damage, and defective stem cell differentiation. Over the past decade, several studies have shown that antioxidants can not only mitigate oxidative stress and improve stem cell survival but also affect the potency and differentiation of these cells. Further beneficial effects of antioxidants include increasing genomic stability, improving the adhesion of stem cells to culture media, and enabling researchers to manipulate stem cell proliferation by using different doses of antioxidants. These findings can have several clinical implications, such as improving neurogenesis in patients with stroke and neurodegenerative diseases, as well as improving the regeneration of infarcted myocardial tissue and the banking of spermatogonial stem cells. This article reviews the cellular and molecular effects of antioxidant supplementation to cultured or transplanted stem cells and draws up recommendations for further research in this area.
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Gao S, Zhao Z, Wu R, Zeng Y, Zhang Z, Miao J, Yuan Z. Bone marrow mesenchymal stem cell transplantation improves radiation-induced heart injury through DNA damage repair in rat model. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2017; 56:63-77. [PMID: 28025714 DOI: 10.1007/s00411-016-0675-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 12/19/2016] [Indexed: 06/06/2023]
Abstract
Radiotherapy is an effective form of therapy for most thoracic malignant tumors. However, myocardial injury resulting from the high doses of radiation is a severe complication. Here we aimed to study the possibility of reducing radiation-induced myocardial injury with mesenchymal stem cell (MSC) transplantation. We used MSCs extracted from bone marrow (BMSCs) to transplant via the tail vein into a radiation-induced heart injury (RIHI) rat model. The rats were divided into six groups: a Sham group, an IRR (irradiation) group, and four IRR + BMSCs transplantation groups obtained at different time points. After irradiation, BMSC transplantation significantly enhanced the cardiac function in rats. By analyzing the expression of PPAR-α, PPAR-γ, TGF-β, IL-6, and IL-8, we found that BMSC transplantation alleviated radiation-induced myocardial fibrosis and decreased the inflammatory reaction. Furthermore, we found that expression of γ-H2AX, XRCC4, DNA ligase4, and TP53BP1, which are associated with DNA repair, was up-regulated, along with increased secretion of growth factors SDF-1, CXCR4, VEGF, and IGF in rat myocardium in the IRR + BMSCs transplantation groups compared with the IRR group. Thus, BMSC transplantation has the potential to improve RIHI via DNA repair and be a new therapeutic approach for patients with myocardial injury.
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Affiliation(s)
- Song Gao
- The Second Department of Clinical Oncology, Shengjing Hospital, China Medical University, No. 39 Huaxiang Road, Tiexi District, Shenyang, 110022, China
| | - Zhiying Zhao
- School of Computer Science and Engineering, Northeastern University, No. 3-11, Wenhua Road, Heping District, Shenyang, 110004, China
| | - Rong Wu
- The Second Department of Clinical Oncology, Shengjing Hospital, China Medical University, No. 39 Huaxiang Road, Tiexi District, Shenyang, 110022, China
| | - Yuecan Zeng
- The Second Department of Clinical Oncology, Shengjing Hospital, China Medical University, No. 39 Huaxiang Road, Tiexi District, Shenyang, 110022, China
| | - Zhenyong Zhang
- The Second Department of Clinical Oncology, Shengjing Hospital, China Medical University, No. 39 Huaxiang Road, Tiexi District, Shenyang, 110022, China
| | - Jianing Miao
- Key Laboratory of Shengjing Hospital, China Medical University, No. 7, Economic Development Zone, Benxi, Shenyang, 117004, China
| | - Zhengwei Yuan
- Key Laboratory of Health Ministry for Congenital Malformation, Shengjing Hospital, China Medical University, No. 7, Economic Development Zone, Benxi, 117004, China.
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14
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Pal J, Nanjappa P, Kumar S, Shi J, Buon L, Munshi NC, Shammas MA. Impact of RAD51C-mediated Homologous Recombination on Genomic Integrity in Barrett's Adenocarcinoma Cells. ACTA ACUST UNITED AC 2017; 6:2286-2295. [PMID: 29399538 PMCID: PMC5796564 DOI: 10.17554/j.issn.2224-3992.2017.06.687] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
BACKGROUND In normal cells, RAD51-mediated homologous recombination (HR) is a
precise DNA repair mechanism which plays a key role in the maintenance of
genomic integrity and stability. However, elevated (dysregulated) RAD51 is
implicated in genomic instability and is a potential target for treatment of
certain cancers, including Barrett’s adenocarcinoma (BAC). In this
study, we investigated genomic impact and translational significance of
moderate vs. strong suppression of RAD51 in BAC cells. METHODS BAC cells (FLO-1 and OE33) were transduced with non-targeting control
(CS) or RAD51-specific shRNAs, mediating a moderate (40–50%)
suppression or strong (80-near 100%) suppression of the gene. DNA
breaks, spontaneous or following exposure to DNA damaging agent, were
examined by comet assay and 53BP1 staining. Gene expression was monitored by
microarrays (Affymetrix). Homologous recombination (HR) and single strand
annealing (SSA) activities were measured using plasmid based assays. RESULTS We show that although moderate suppression consistenly
inhibits/reduces HR activity, the strong suppression is associated with
increase in HR activity (by ~15 – ≥ 50% in various
experiments), suggesting activation of RAD51-independent pathway. Contrary
to moderate suppression, a strong suppression of RAD51 is associated with a
significant induced DNA breaks as well as altered expression of genes
involved in detection/processing of DNA breaks and apoptosis. Stronger RAD51
suppression was also associated with mutagenic single strand annealing
mediated HR. Suppression of RAD51C inhibited RAD51-independent
(SSA-mediated) HR in BAC cells. CONCLUSION Elevated (dysregulated) RAD51 in BAC is implicated in both the repair
of DNA breaks as well as ongoing genomic rearrangements. Moderate
suppression of this gene reduces HR activity, whereas strong or near
complete suppression of this gene activates RAD51C-dependent HR involving a
mechanism known as single strand annealing (SSA). SSA-mediated HR, which is
a mutagenic HR pathway, further disrupts genomic integrity by increasing DNA
breaks in BAC cells.
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Affiliation(s)
- Jagannath Pal
- Department of Adult Oncology, Harvard (Dana Farber) Cancer Institute, Boston, MA, the United States. VA Health Care System, West Roxbury, MA, the United States. Multi-disciplinary Research Units (MRUs), Pt J.N.M. Medical College, Raipur, CG, India
| | - Purushothama Nanjappa
- Department of Adult Oncology, Harvard (Dana Farber) Cancer Institute, Boston, MA, the United States. VA Health Care System, West Roxbury, MA, the United States
| | - Subodh Kumar
- Department of Adult Oncology, Harvard (Dana Farber) Cancer Institute, Boston, MA, the United States. VA Health Care System, West Roxbury, MA, the United States
| | - Jialan Shi
- Department of Adult Oncology, Harvard (Dana Farber) Cancer Institute, Boston, MA, the United States. VA Health Care System, West Roxbury, MA, the United States. Department of Medicine, Harvard Medical School, Boston, MA, the United States
| | - Leutz Buon
- Department of Adult Oncology, Harvard (Dana Farber) Cancer Institute, Boston, MA, the United States
| | - Nikhil C Munshi
- Department of Adult Oncology, Harvard (Dana Farber) Cancer Institute, Boston, MA, the United States. VA Health Care System, West Roxbury, MA, the United States. Department of Medicine, Harvard Medical School, Boston, MA, the United States
| | - Masood A Shammas
- Department of Adult Oncology, Harvard (Dana Farber) Cancer Institute, Boston, MA, the United States. VA Health Care System, West Roxbury, MA, the United States
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15
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Mansilla SF, Bertolin AP, Bergoglio V, Pillaire MJ, González Besteiro MA, Luzzani C, Miriuka SG, Cazaux C, Hoffmann JS, Gottifredi V. Cyclin Kinase-independent role of p21 CDKN1A in the promotion of nascent DNA elongation in unstressed cells. eLife 2016; 5. [PMID: 27740454 PMCID: PMC5120883 DOI: 10.7554/elife.18020] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 10/07/2016] [Indexed: 01/01/2023] Open
Abstract
The levels of the cyclin-dependent kinase (CDK) inhibitor p21 are low in S phase and insufficient to inhibit CDKs. We show here that endogenous p21, instead of being residual, it is functional and necessary to preserve the genomic stability of unstressed cells. p21depletion slows down nascent DNA elongation, triggers permanent replication defects and promotes the instability of hard-to-replicate genomic regions, namely common fragile sites (CFS). The p21’s PCNA interacting region (PIR), and not its CDK binding domain, is needed to prevent the replication defects and the genomic instability caused by p21 depletion. The alternative polymerase kappa is accountable for such defects as they were not observed after simultaneous depletion of both p21 and polymerase kappa. Hence, in CDK-independent manner, endogenous p21 prevents a type of genomic instability which is not triggered by endogenous DNA lesions but by a dysregulation in the DNA polymerase choice during genomic DNA synthesis. DOI:http://dx.doi.org/10.7554/eLife.18020.001 Cancer develops when cells in the body mutate in ways that allow them to rapidly grow and divide. To protect cells from becoming cancerous, various molecules act like guardians to prevent cells from dividing when their DNA is damaged, or if they are short of energy. Other guardian molecules monitor the DNA copying process to ensure that the newly-made DNA is as identical as possible to the original DNA template. A protein called p21 belongs to the first group of guardian molecules: DNA damage triggers the production of p21, which prevents the cell from copying its DNA. This role relies on a section of the protein called the CDK binding domain. Cells that have already started to copy their genetic material also have low levels of p21. Mansilla et al. used human cells to investigate whether p21 is also involved in the process of copying DNA. The experiments show that the low levels of p21 act to increase the speed at which the DNA is copied. This activity helps to ensure that all of the cell’s DNA is copied within the time available, including sections of DNA that are harder to copy because they are more fragile and prone to damage. This newly identified role does not involve the CDK binding domain, but instead requires a different section of the p21 protein known as the PCNA interacting region. Mansilla et al. propose that p21 plays a dual role in protecting us from developing cancer. The PCNA interacting region is also found in other proteins that are involved in copying DNA. Therefore, a future challenge is to find out how these proteins interact with each other to ensure that cells accurately copy their DNA in a timely fashion. DOI:http://dx.doi.org/10.7554/eLife.18020.002
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Affiliation(s)
- Sabrina F Mansilla
- Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Agustina P Bertolin
- Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Valérie Bergoglio
- Centre de Recherches en Cancérologie de Toulouse, Toulouse, France.,INSERM, Universite Paul Sabatier-CNRS, Université de Toulouse, Toulouse, France.,Laboratoire d'Excellence TOUCAN, Toulouse, France.,Equipe labellisée La Ligue contre le Cancer, Toulouse, France
| | - Marie-Jeanne Pillaire
- Centre de Recherches en Cancérologie de Toulouse, Toulouse, France.,INSERM, Universite Paul Sabatier-CNRS, Université de Toulouse, Toulouse, France.,Laboratoire d'Excellence TOUCAN, Toulouse, France.,Equipe labellisée La Ligue contre le Cancer, Toulouse, France
| | - Marina A González Besteiro
- Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Carlos Luzzani
- Laboratorio de Investigaciones Aplicadas en Neurociencias, Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia, Belén de Escobar, Argentina
| | - Santiago G Miriuka
- Laboratorio de Investigaciones Aplicadas en Neurociencias, Fundación para la Lucha contra las Enfermedades Neurológicas de la Infancia, Belén de Escobar, Argentina
| | - Christophe Cazaux
- Centre de Recherches en Cancérologie de Toulouse, Toulouse, France.,INSERM, Universite Paul Sabatier-CNRS, Université de Toulouse, Toulouse, France.,Laboratoire d'Excellence TOUCAN, Toulouse, France.,Equipe labellisée La Ligue contre le Cancer, Toulouse, France
| | - Jean-Sébastien Hoffmann
- Centre de Recherches en Cancérologie de Toulouse, Toulouse, France.,INSERM, Universite Paul Sabatier-CNRS, Université de Toulouse, Toulouse, France.,Laboratoire d'Excellence TOUCAN, Toulouse, France.,Equipe labellisée La Ligue contre le Cancer, Toulouse, France
| | - Vanesa Gottifredi
- Fundación Instituto Leloir-Instituto de Investigaciones Bioquímicas de Buenos Aires, Consejo de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
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16
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Cirauqui B, Margelí M, Quiroga V, Quer A, Karachaliou N, Chaib I, Ramírez JL, Muñoz A, Pollán C, Planas I, Drozdowsky A, Rosell R. DNA repair pathways to regulate response to chemoradiotherapy in patients with locally advanced head and neck cancer. Tumour Biol 2016; 37:13435-13443. [PMID: 27465548 DOI: 10.1007/s13277-016-5149-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/11/2016] [Indexed: 11/26/2022] Open
Abstract
Platinum-based chemoradiotherapy (CRT) is a preferred standard of care for locally advanced head and neck cancer (HNC). However, survival benefit is small, with substantial toxicity and biomarkers of CRT resistance that could guide treatment selection and spare morbidity. Increased DNA repair in solid tumors may contribute to cancer cells' ability to survive in genotoxic stress environments afforded by therapy. We assessed mRNA expression levels of DNA repair-related genes BRCA1, RAP80, 53 binding protein 1 (53BP1), mediator of DNA damage checkpoint 1 (MDC1), and RNF8. We correlated our findings with response and overall survival in 72 head and neck patients treated with weekly carboplatin AUC 2 and radiotherapy. Complete response (CR) to CRT was 50 % in patients with low levels of 53BP1 compared to 6.3 % in patients with high levels (p = 0.0059). Of high BRCA1 mRNA expressors, 41.2 % had CR compared to 29.4 % of low expressors (p = 0.72). For a small group of patients with low 53BP1 and either high BRCA1 or RAP80, CRs were 66.7 and 71.4 %, respectively. A trend for better overall survival (OS) was found for patients with low 53BP1 (15 vs 8 m; p = 0.056). Our findings highlight the potential usefulness of 53BP1 mRNA as a predictive biomarker of response and overall survival in HNC patients treated with chemoradiotherapy. Those with high 53BP1 expression could derive only a meager benefit from treatment. Analysis of BRCA1 and RAP80 could further reinforce the predictive value of 53BP1. Although this was a retrospective study with small sample size, it could inform larger translational studies in HNC.
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Affiliation(s)
- B Cirauqui
- Medical Oncology, Institut Català d'Oncologia Badalona-HU Germans Trias i Pujol, Autonomous University of Barcelona, Badalona, Barcelona, Spain.
| | - M Margelí
- Medical Oncology, Institut Català d'Oncologia Badalona-HU Germans Trias i Pujol, Autonomous University of Barcelona, Badalona, Barcelona, Spain
| | - V Quiroga
- Medical Oncology, Institut Català d'Oncologia Badalona-HU Germans Trias i Pujol, Autonomous University of Barcelona, Badalona, Barcelona, Spain
| | - A Quer
- Pathological Anatomy, HU Germans Trias i Pujol, Badalona, Barcelona, Spain
| | - N Karachaliou
- Quirón Dexeus University Institute, Barcelona, Spain
| | - I Chaib
- Laboratory of Molecular Biology, Institut Català d'Oncologia Badalona, Barcelona, Spain
| | - J L Ramírez
- Laboratory of Molecular Biology, Institut Català d'Oncologia Badalona, Barcelona, Spain
| | - A Muñoz
- Pathological Anatomy, HU Germans Trias i Pujol, Badalona, Barcelona, Spain
| | - C Pollán
- Otolaryngology, HU Germans Trias i Pujol, Badalona, Barcelona, Spain
| | - I Planas
- Radiation Oncology, Institut Català d'Oncologia Badalona-HU Germans Trias i Pujol, Badalona, Barcelona, Spain
| | | | - R Rosell
- Quirón Dexeus University Institute, Barcelona, Spain
- Laboratory of Molecular Biology, Institut Català d'Oncologia Badalona, Barcelona, Spain
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17
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The FEN1 L209P mutation interferes with long-patch base excision repair and induces cellular transformation. Oncogene 2016; 36:194-207. [PMID: 27270424 PMCID: PMC5140775 DOI: 10.1038/onc.2016.188] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 04/12/2016] [Accepted: 04/12/2016] [Indexed: 12/20/2022]
Abstract
Flap endonuclease-1 (FEN1) is a multifunctional, structure-specific nuclease that has a critical role in maintaining human genome stability. FEN1 mutations have been detected in human cancer specimens and have been suggested to cause genomic instability and cancer predisposition. However, the exact relationship between FEN1 deficiency and cancer susceptibility remains unclear. In the current work, we report a novel colorectal cancer-associated FEN1 mutation, L209P. This mutant protein lacks the FEN, exonuclease (EXO) and gap endonuclease (GEN) activities of FEN1 but retains DNA-binding affinity. The L209P FEN1 variant interferes with the function of the wild-type FEN1 enzyme in a dominant-negative manner and impairs long-patch base excision repair in vitro and in vivo. Expression of L209P FEN1 sensitizes cells to DNA damage, resulting in endogenous genomic instability and cellular transformation, as well as tumor growth in a mouse xenograft model. These data indicate that human cancer-associated genetic alterations in the FEN1 gene can contribute substantially to cancer development.
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18
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Casafont I, Palanca A, Lafarga V, Mata-Garrido J, Berciano MT, Lafarga M. Dynamic Behavior of the RNA Polymerase II and the Ubiquitin Proteasome System During the Neuronal DNA Damage Response to Ionizing Radiation. Mol Neurobiol 2015; 53:6799-6808. [PMID: 26660115 DOI: 10.1007/s12035-015-9565-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 11/29/2015] [Indexed: 12/20/2022]
Abstract
Neurons are highly vulnerable to genotoxic agents. To restore genome integrity upon DNA lesions, neurons trigger a DNA damage response (DDR) that requires chromatin modifications and transcriptional silencing at DNA damage sites. To study the reorganization of the active RNA polymerase II (Pol II), which transcribes all mRNA-encoding genes, and the participation of the ubiquitin-proteasome system (UPS) in the neuronal DDR, we have used rat sensory ganglion neurons exposed to X-rays (4 Gy) ionizing radiation (IR). In control neurons, Pol II appears concentrated in numerous chromatin microfoci identified as transcription factories by the incorporation of 5'-fluorouridine into nascent RNA. Upon IR treatment, numerous IR-induced foci (IRIF), which were immunoreactive for γH2AX and 53BP1, were observed as early as 30 min post-IR; their number progressively reduced at 3 h, 1 day, and 3 days post-IR. The formation of IRIF was associated with a decrease in Pol II levels by both immunofluorescence and Western blotting. Treatment with the proteasome inhibitor bortezomib strongly increased Pol II levels in both control and irradiated neurons, suggesting that proteasome plays a proteolytic role by clearing stalled Pol II complexes at DNA damage sites, as a prelude to DNA repair. Neuronal IRIF recruited ubiquitylated proteins, including ubiquitylated histone H2A (Ub-H2A), and the catalytic proteasome 20S. Ub-H2A has been associated with transcriptional silencing at DNA damage sites. On the other hand, the participation of UPS in neuronal DDR may be essential for the ubiquitylation of Pol II and other proteasome substrates of the DNA repair machinery and their subsequent proteasome-mediated degradation.
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Affiliation(s)
- Iñigo Casafont
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Cardenal Herrera Oria s/N, Santander, 39011, Spain
| | - Ana Palanca
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Cardenal Herrera Oria s/N, Santander, 39011, Spain
| | - Vanesa Lafarga
- Laboratorio de Inestabilidad Genómica, Centro Nacional de Investigaciones Oncológicas (CNIO), Madrid, Spain
| | - Jorge Mata-Garrido
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Cardenal Herrera Oria s/N, Santander, 39011, Spain
| | - Maria T Berciano
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Cardenal Herrera Oria s/N, Santander, 39011, Spain
| | - Miguel Lafarga
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Cardenal Herrera Oria s/N, Santander, 39011, Spain.
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19
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Dokic I, Niklas M, Zimmermann F, Mairani A, Seidel P, Krunic D, Jäkel O, Debus J, Greilich S, Abdollahi A. Correlation of Particle Traversals with Clonogenic Survival Using Cell-Fluorescent Ion Track Hybrid Detector. Front Oncol 2015; 5:275. [PMID: 26697410 PMCID: PMC4671278 DOI: 10.3389/fonc.2015.00275] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/23/2015] [Indexed: 01/26/2023] Open
Abstract
Development of novel approaches linking the physical characteristics of particles with biological responses are of high relevance for the field of particle therapy. In radiobiology, the clonogenic survival of cells is considered the gold standard assay for the assessment of cellular sensitivity to ionizing radiation. Toward further development of next generation biodosimeters in particle therapy, cell-fluorescent ion track hybrid detector (Cell-FIT-HD) was recently engineered by our group and successfully employed to study physical particle track information in correlation with irradiation-induced DNA damage in cell nuclei. In this work, we investigated the feasibility of Cell-FIT-HD as a tool to study the effects of clinical beams on cellular clonogenic survival. Tumor cells were grown on the fluorescent nuclear track detector as cell culture, mimicking the standard procedures for clonogenic assay. Cell-FIT-HD was used to detect the spatial distribution of particle tracks within colony-initiating cells. The physical data were associated with radiation-induced foci as surrogates for DNA double-strand breaks, the hallmark of radiation-induced cell lethality. Long-term cell fate was monitored to determine the ability of cells to form colonies. We report the first successful detection of particle traversal within colony-initiating cells at subcellular resolution using Cell-FIT-HD.
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Affiliation(s)
- Ivana Dokic
- German Cancer Consortium, Translational Radiation Oncology, National Center for Tumor Diseases, German Cancer Research Center, Heidelberg University Medical School , Heidelberg , Germany ; Heidelberg Ion Therapy Center , Heidelberg , Germany ; Heidelberg Institute of Radiation Oncology, National Center for Radiation Research in Oncology , Heidelberg , Germany
| | - Martin Niklas
- German Cancer Consortium, Translational Radiation Oncology, National Center for Tumor Diseases, German Cancer Research Center, Heidelberg University Medical School , Heidelberg , Germany ; Heidelberg Ion Therapy Center , Heidelberg , Germany ; Heidelberg Institute of Radiation Oncology, National Center for Radiation Research in Oncology , Heidelberg , Germany
| | - Ferdinand Zimmermann
- German Cancer Consortium, Translational Radiation Oncology, National Center for Tumor Diseases, German Cancer Research Center, Heidelberg University Medical School , Heidelberg , Germany ; Heidelberg Ion Therapy Center , Heidelberg , Germany ; Heidelberg Institute of Radiation Oncology, National Center for Radiation Research in Oncology , Heidelberg , Germany
| | - Andrea Mairani
- Heidelberg Ion Therapy Center , Heidelberg , Germany ; National Center for Oncological Hadrontherapy , Pavia , Italy
| | - Philipp Seidel
- German Cancer Consortium, Translational Radiation Oncology, National Center for Tumor Diseases, German Cancer Research Center, Heidelberg University Medical School , Heidelberg , Germany ; Heidelberg Ion Therapy Center , Heidelberg , Germany ; Heidelberg Institute of Radiation Oncology, National Center for Radiation Research in Oncology , Heidelberg , Germany
| | - Damir Krunic
- Light Microscopy Facility, German Cancer Research Center , Heidelberg , Germany
| | - Oliver Jäkel
- Heidelberg Ion Therapy Center , Heidelberg , Germany ; Heidelberg Institute of Radiation Oncology, National Center for Radiation Research in Oncology , Heidelberg , Germany ; Division of Medical Physics in Radiation Oncology, German Cancer Research Center , Heidelberg , Germany
| | - Jürgen Debus
- German Cancer Consortium, Translational Radiation Oncology, National Center for Tumor Diseases, German Cancer Research Center, Heidelberg University Medical School , Heidelberg , Germany ; Heidelberg Ion Therapy Center , Heidelberg , Germany ; Heidelberg Institute of Radiation Oncology, National Center for Radiation Research in Oncology , Heidelberg , Germany
| | - Steffen Greilich
- Heidelberg Institute of Radiation Oncology, National Center for Radiation Research in Oncology , Heidelberg , Germany ; Division of Medical Physics in Radiation Oncology, German Cancer Research Center , Heidelberg , Germany
| | - Amir Abdollahi
- German Cancer Consortium, Translational Radiation Oncology, National Center for Tumor Diseases, German Cancer Research Center, Heidelberg University Medical School , Heidelberg , Germany ; Heidelberg Ion Therapy Center , Heidelberg , Germany ; Heidelberg Institute of Radiation Oncology, National Center for Radiation Research in Oncology , Heidelberg , Germany
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20
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Yu M, Liu K, Mao Z, Luo J, Gu W, Zhao W. USP11 Is a Negative Regulator to γH2AX Ubiquitylation by RNF8/RNF168. J Biol Chem 2015; 291:959-67. [PMID: 26507658 DOI: 10.1074/jbc.m114.624478] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Indexed: 11/06/2022] Open
Abstract
Ubiquitin modification at double strand breaks (DSB) sites is an essential regulator of signaling and repair. γH2AX extends from DSB sites and provides a platform for subsequent recruitment and amplification of DNA repair proteins and signaling factors. Here, we found that RNF8/RNF168 ubiquitylates γH2AX. We identified that USP11 is a unique deubiquitylation enzyme for γH2AX. USP11 deubiquitylates γH2AX both in vivo and in vitro but not the canonical (ub)-K119-H2A and (ub)-K120-H2B in vitro, and USP11 ablation enhances the levels of γH2AX ubiquitylation. We also found that USP11 interacts with γH2AX both in vivo and in vitro. We found that 53BP1 and ubiquitin-conjugated proteins are misregulated to be retained longer and stronger at DSB sites after knockdown of USP11. We further found that cells are hypersensitive to γ-irradiation after ablation of USP11. Together, our findings elucidate deeply and extensively the mechanism of RNF8/RNF168 and USP11 to maintain the proper status of ubiquitylation γH2AX to repair DSB.
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Affiliation(s)
- Miao Yu
- From the Department of Biochemistry and Molecular Biology, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function and
| | - Kun Liu
- From the Department of Biochemistry and Molecular Biology, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function and
| | - Zebin Mao
- From the Department of Biochemistry and Molecular Biology, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function and
| | - Jianyuan Luo
- the Department of Genetics, Peking University Health Science Center, Beijing, 100191, China and
| | - Wei Gu
- the Institute for Cancer Genetics, and Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York 10032
| | - Wenhui Zhao
- From the Department of Biochemistry and Molecular Biology, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function and
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21
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Dental composite components induce DNA-damage and altered nuclear morphology in gingiva fibroblasts. Dent Mater 2015; 31:1335-44. [PMID: 26382061 DOI: 10.1016/j.dental.2015.08.156] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Revised: 07/31/2015] [Accepted: 08/17/2015] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Released dental composite components can damage human gingival fibroblasts (HGFs) and their DNA. The cytotoxicity, chromatin condensation and the induction of DNA double strand breaks (DSBs) by different compounds of dental composites was investigated using an improved γ-H2AX focus assay. METHODS HGFs were incubated with the monomers: bisphenol-A-ethoxylate-dimethacrylate (Bis-DMA), bisphenol-A-glycerolate-dimethacrylate (BisGMA), ethyltriethylen glycol methacrylate (ETEGMA), glycidyl methacrylate (GMA), 1,6-hexandiol-dimethycrylate (HDDMA), trimethylolpropane ethoxylate triacrylate (TMPTA), and acrylamide (ACR). DSBs were determined by enumerating γ-H2AX and 53BP1 foci colocalized at DSBs. RESULTS A concentration-dependent induction of DSBs was found in the order: GMA>BisGMA>ACR>Bis-DMA>HDDMA>TMPTA>ETEGMA. HGFs exposure to GMA (0.3mM) and to BisGMA (0.09mM) induced the highest rate of DSB foci, i.e. 12-fold and 8-fold, respectively, relative to control (0.33 DSB foci/cell). At the highest concentrations (EC50) prominent changes in the chromatin morphology of HGF cell nuclei, i.e. compaction of nuclear chromatin and reduction of the area covered by the ovoid fibroblast nuclei, were observed. Nuclear condensation was significantly induced by GMA (1.7-fold at 0.3mM) and BisGMA (1.6-fold at 0.09mM), which correlated with the highest numbers of induced DSB foci (GMA, BisGMA, 3.9 and 2.6 foci/cell, respectively). SIGNIFICANCE The improved γ-H2AX/53BP1 focus assay revealed a concentration-dependent increase in DSBs for all tested substances. Furthermore, concentration-dependent changes in HGF cell nucleus morphology was noted, demonstrating genotoxic effects of the substances tested.
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Romero AM, Palanca A, Ruiz-Soto M, Llorca J, Marín MP, Renau-Piqueras J, Berciano MT, Lafarga M. Chronic Alcohol Exposure Decreases 53BP1 Protein Levels Leading to a Defective DNA Repair in Cultured Primary Cortical Neurons. Neurotox Res 2015; 29:69-79. [PMID: 26264240 DOI: 10.1007/s12640-015-9554-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/08/2015] [Accepted: 08/04/2015] [Indexed: 12/24/2022]
Abstract
Chronic alcohol consumption may cause neurodevelopmental and neurodegenerative disorders. Alcohol neurotoxicity is associated with the production of acetaldehyde and reactive oxygen species that induce oxidative DNA damage. However, the molecular mechanisms by which ethanol disturbs the DNA damage response (DDR), resulting in a defective DNA repair, remain unknown. Here, we have used cultured primary cortical neurons exposed to 50 or 100 mM ethanol for 7 days to analyze the ethanol-induced DDR. Ethanol exposure produced a dose-dependent generation of double strand breaks and the formation of DNA damage foci immunoreactive for the histone γH2AX, a DNA damage marker, and for the ubiquitylated H2A, which is involved in chromatin remodeling at DNA damage sites. Importantly, these DNA damage foci failed to recruit the protein 53BP1, a crucial DNA repair factor. This effect was associated with a drop in 53BP1 mRNA and protein levels and with an inhibition of global transcription. Moreover, ethanol-exposed neurons treated with ionizing radiation (2 Gy) also failed to recruit 53BP1 at DNA damage foci and exhibited a greater vulnerability to DNA lesions than irradiated control neurons. Our results support that defective DNA repair, mediated by the deficient expression and recruitment of 53BP1 to DNA damage sites, represents a novel mechanism involved in ethanol neurotoxicity. The design of therapeutic strategies that increase or stabilize 53BP1 levels might potentially promote DNA repair and partially compensate alcohol neurotoxicity.
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Affiliation(s)
- Ana M Romero
- Sección de Biología y Patología Celular, Centro de Investigación, Hospital La Fe, Valencia, Spain.,Unidad de Microscopía IIS La Fe, Valencia, Spain
| | - Ana Palanca
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Av. Cardenal Herrera Oria s/n, 39011, Santander, Spain
| | - Maria Ruiz-Soto
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Av. Cardenal Herrera Oria s/n, 39011, Santander, Spain
| | - Javier Llorca
- Division of Epidemiology and Public Health, "CIBER de Epidemiología y Salud Pública (CIBERESP)", IDIVAL, University of Cantabria, Santander, Spain
| | | | - Jaime Renau-Piqueras
- Sección de Biología y Patología Celular, Centro de Investigación, Hospital La Fe, Valencia, Spain
| | - Maria T Berciano
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Av. Cardenal Herrera Oria s/n, 39011, Santander, Spain
| | - Miguel Lafarga
- Department of Anatomy and Cell Biology and "Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)", University of Cantabria-IDIVAL, Av. Cardenal Herrera Oria s/n, 39011, Santander, Spain.
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Boucher D, Vu T, Bain AL, Tagliaro‐Jahns M, Shi W, Lane SW, Khanna KK. Ssb2/Nabp1
is dispensable for thymic maturation, male fertility, and DNA repair in mice. FASEB J 2015; 29:3326-3334. [DOI: 10.1096/fj.14-269944] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Affiliation(s)
- Didier Boucher
- Signal Transduction LaboratoryQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
| | - Therese Vu
- Translational Leukaemia ResearchQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
- University of QueenslandBrisbaneQueenslandAustralia
| | - Amanda L. Bain
- Signal Transduction LaboratoryQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
| | - Marina Tagliaro‐Jahns
- Signal Transduction LaboratoryQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
- Institut National De La Recherche AgronomiqueInstitut Jean‐Pierre BourginUnité Mixte de Recherche 1318, Équipes de Recherche Labellisées Centre National de la Recherche Scientifique 3559, Saclay Plant SciencesVersaillesFrance
| | - Wei Shi
- Signal Transduction LaboratoryQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
| | - Steven W. Lane
- Translational Leukaemia ResearchQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
| | - Kum Kum Khanna
- Signal Transduction LaboratoryQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
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24
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Ulrike K, Markus H, Thomas H, Ellen H, Barbara S, Rainer F, Distel LV. NNRTI-based antiretroviral therapy may increase risk of radiation induced side effects in HIV-1-infected patients. Radiother Oncol 2015; 116:323-30. [PMID: 26183311 DOI: 10.1016/j.radonc.2015.07.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 05/24/2015] [Accepted: 07/02/2015] [Indexed: 11/30/2022]
Abstract
PURPOSE As the incidence of cancer is rising in HIV-1-infected patients, radiotherapy is used more frequently in this patient group. Strong radiation induced side effects have been reported in single patients on antiretroviral therapy. Thus we investigated whether HIV-1 itself or antiretroviral drugs could enhance radiosensitivity in patients. METHODS AND MATERIALS Radiosensitivity after in vitro irradiation of blood lymphocytes was tested in 196 individuals (80 HIV-1-infected patients and 116 healthy controls and cancer patients) using a three color fluorescence in situ hybridization approach to analyze chromosomal aberrations (B/M). Additionally, the NNRTI efavirenz and the NRTIs tenofovir and emtricitabine were tested for radiosensitizing effects in vitro. RESULTS Lymphocytes from HIV-1-infected patients in the NNRTI + NRTI group were significantly more sensitive to ionizing radiation than in the other groups (patients without treatment or with NRTI + PI or HIV-negative controls). In vitro the triple medication efavirenz, tenofovir and emtricitabine leads to a reduced survival fraction and an increased activation of the DNA repair proteins H2AX, Nbs, Atm and 53BP1 in combination with ionizing radiation. CONCLUSIONS HIV-1 treatment with NNRTI containing therapy regimes possibly sensitizes a subgroup of patients to ionizing radiation. Individual radiosensitivity of HIV-1-infected patients on HAART including NNRTI should be tested before starting radiotherapy.
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Affiliation(s)
- Keller Ulrike
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-University of Erlangen-Nürnberg, Germany
| | - Hecht Markus
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-University of Erlangen-Nürnberg, Germany
| | - Harrer Thomas
- Department of Internal Medicine 3, University Hospital Erlangen, Friedrich-Alexander-University of Erlangen-Nürnberg, Germany
| | - Harrer Ellen
- Department of Internal Medicine 3, University Hospital Erlangen, Friedrich-Alexander-University of Erlangen-Nürnberg, Germany
| | - Schuster Barbara
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-University of Erlangen-Nürnberg, Germany
| | - Fietkau Rainer
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-University of Erlangen-Nürnberg, Germany
| | - Luitpold V Distel
- Department of Radiation Oncology, University Hospital Erlangen, Friedrich-Alexander-University of Erlangen-Nürnberg, Germany.
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25
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Brown JS, Jackson SP. Ubiquitylation, neddylation and the DNA damage response. Open Biol 2015; 5:150018. [PMID: 25833379 PMCID: PMC4422126 DOI: 10.1098/rsob.150018] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 03/09/2015] [Indexed: 12/19/2022] Open
Abstract
Failure of accurate DNA damage sensing and repair mechanisms manifests as a variety of human diseases, including neurodegenerative disorders, immunodeficiency, infertility and cancer. The accuracy and efficiency of DNA damage detection and repair, collectively termed the DNA damage response (DDR), requires the recruitment and subsequent post-translational modification (PTM) of a complex network of proteins. Ubiquitin and the ubiquitin-like protein (UBL) SUMO have established roles in regulating the cellular response to DNA double-strand breaks (DSBs). A role for other UBLs, such as NEDD8, is also now emerging. This article provides an overview of the DDR, discusses our current understanding of the process and function of PTM by ubiquitin and NEDD8, and reviews the literature surrounding the role of ubiquitylation and neddylation in DNA repair processes, focusing particularly on DNA DSB repair.
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Affiliation(s)
- Jessica S Brown
- The Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
| | - Stephen P Jackson
- The Wellcome Trust and Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, UK
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26
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Doksani Y, de Lange T. The role of double-strand break repair pathways at functional and dysfunctional telomeres. Cold Spring Harb Perspect Biol 2014; 6:a016576. [PMID: 25228584 DOI: 10.1101/cshperspect.a016576] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Telomeres have evolved to protect the ends of linear chromosomes from the myriad of threats posed by the cellular DNA damage signaling and repair pathways. Mammalian telomeres have to block nonhomologous end joining (NHEJ), thus preventing chromosome fusions; they need to control homologous recombination (HR), which could change telomere lengths; they have to avoid activating the ATM (ataxia telangiectasia mutated) and ATR (ATM- and RAD3-related) kinase pathways, which could induce cell cycle arrest; and they have to protect chromosome ends from hyperresection. Recent studies of telomeres have provided insights into the mechanisms of NHEJ and HR, how these double-strand break (DSB) repair pathways can be thwarted, and how telomeres have co-opted DNA repair factors to help in the protection of chromosome ends. These aspects of telomere biology are reviewed here with particular emphasis on recombination, the main focus of this collection.
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Affiliation(s)
- Ylli Doksani
- Laboratory for Cell Biology and Genetics, Rockefeller University, New York, New York 10065
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, Rockefeller University, New York, New York 10065
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27
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Mehta A, Haber JE. Sources of DNA double-strand breaks and models of recombinational DNA repair. Cold Spring Harb Perspect Biol 2014; 6:a016428. [PMID: 25104768 PMCID: PMC4142968 DOI: 10.1101/cshperspect.a016428] [Citation(s) in RCA: 476] [Impact Index Per Article: 47.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
DNA is subject to many endogenous and exogenous insults that impair DNA replication and proper chromosome segregation. DNA double-strand breaks (DSBs) are one of the most toxic of these lesions and must be repaired to preserve chromosomal integrity. Eukaryotes are equipped with several different, but related, repair mechanisms involving homologous recombination, including single-strand annealing, gene conversion, and break-induced replication. In this review, we highlight the chief sources of DSBs and crucial requirements for each of these repair processes, as well as the methods to identify and study intermediate steps in DSB repair by homologous recombination.
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Affiliation(s)
- Anuja Mehta
- Rosenstiel Basic Medical Sciences Research Center, MS029 Rosenstiel Center, Brandeis University, Waltham, Massachusetts 02454-9110
| | - James E Haber
- Rosenstiel Basic Medical Sciences Research Center, MS029 Rosenstiel Center, Brandeis University, Waltham, Massachusetts 02454-9110
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28
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The predictive value of 53BP1 and BRCA1 mRNA expression in advanced non-small-cell lung cancer patients treated with first-line platinum-based chemotherapy. Oncotarget 2014; 4:1572-81. [PMID: 24197907 PMCID: PMC3858546 DOI: 10.18632/oncotarget.1157] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Platinum-based chemotherapy is the standard first-line treatment for non-oncogene-addicted non-small cell lung cancers (NSCLCs) and the analysis of multiple DNA repair genes could improve current models for predicting chemosensitivity. We investigated the potential predictive role of components of the 53BP1 pathway in conjunction with BRCA1. The mRNA expression of BRCA1, MDC1, CASPASE3, UBC13, RNF8, 53BP1, PIAS4, UBC9 and MMSET was analyzed by real-time PCR in 115 advanced NSCLC patients treated with first-line platinum-based chemotherapy. Patients expressing low levels of both BRCA1 and 53BP1 obtained a median progression-free survival of 10.3 months and overall survival of 19.3 months, while among those with low BRCA1 and high 53BP1 progression-free survival was 5.9 months (P <0.0001) and overall survival was 8.2 months (P=0.001). The expression of 53BP1 refines BRCA1-based predictive modeling to identify patients most likely to benefit from platinum-based chemotherapy.
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29
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Salminen A, Kauppinen A, Hiltunen M, Kaarniranta K. Krebs cycle intermediates regulate DNA and histone methylation: epigenetic impact on the aging process. Ageing Res Rev 2014; 16:45-65. [PMID: 24910305 DOI: 10.1016/j.arr.2014.05.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 05/20/2014] [Accepted: 05/29/2014] [Indexed: 02/01/2023]
Abstract
Many aging theories have proposed that mitochondria and energy metabolism have a major role in the aging process. There are recent studies indicating that Krebs cycle intermediates can shape the epigenetic landscape of chromatin by regulating DNA and histone methylation. A growing evidence indicates that epigenetics plays an important role in the regulation of healthspan but also is involved in the aging process. 2-Oxoglutarate (α-ketoglutarate) is a key metabolite in the Krebs cycle but it is also an obligatory substrate for 2-oxoglutarate-dependent dioxygenases (2-OGDO). The 2-OGDO enzyme family includes the major enzymes of DNA and histone demethylation, i.e. Ten-Eleven Translocation (TETs) and Jumonji C domain containing (JmjC) demethylases. In addition, 2-OGDO members can regulate collagen synthesis and hypoxic responses in a non-epigenetical manner. Interestingly, succinate and fumarate, also Krebs cycle intermediates, are potent inhibitors of 2-OGDO enzymes, i.e. the balance of Krebs cycle reactions can affect the level of DNA and histone methylation and thus control gene expression. We will review the epigenetic mechanisms through which Krebs cycle intermediates control the DNA and histone methylation. We propose that age-related disturbances in the Krebs cycle function induce stochastic epigenetic changes in chromatin structures which in turn promote the aging process.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland.
| | - Anu Kauppinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland
| | - Mikko Hiltunen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Neurology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Department of Ophthalmology, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland
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30
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Silva BA, Stambaugh JR, Yokomori K, Shah JV, Berns MW. DNA damage to a single chromosome end delays anaphase onset. J Biol Chem 2014; 289:22771-22784. [PMID: 24982423 DOI: 10.1074/jbc.m113.535955] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Chromosome ends contain nucleoprotein structures known as telomeres. Damage to chromosome ends during interphase elicits a DNA damage response (DDR) resulting in cell cycle arrest. However, little is known regarding the signaling from damaged chromosome ends (designated here as "TIPs") during mitosis. In the present study, we investigated the consequences of DNA damage induced at a single TIP in mitosis. We used laser microirradiation to damage mitotic TIPs or chromosome arms (non-TIPs) in PtK2 kidney epithelial cells. We found that damage to a single TIP, but not a non-TIP, delays anaphase onset. This TIP-specific checkpoint response is accompanied by differential recruitment of DDR proteins. Although phosphorylation of H2AX and the recruitment of several repair factors, such as Ku70-Ku80, occur in a comparable manner at both TIP and non-TIP damage sites, DDR factors such as ataxia telangiectasia mutated (ATM), MDC1, WRN, and FANCD2 are specifically recruited to TIPs but not to non-TIPs. In addition, Nbs1, BRCA1, and ubiquitin accumulate at damaged TIPs more rapidly than at damaged non-TIPs. ATR and 53BP1 are not detected at either TIPs or non-TIPs in mitosis. The observed delay in anaphase onset is dependent on the activity of DDR kinases ATM and Chk1, and the spindle assembly checkpoint kinase Mps1. Cells damaged at a single TIP or non-TIP eventually exit mitosis with unrepaired lesions. Damaged TIPs are segregated into micronuclei at a significantly higher frequency than damaged non-TIPs. Together, these findings reveal a mitosis-specific DDR uniquely associated with chromosome ends.
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Affiliation(s)
- Bárbara Alcaraz Silva
- Beckman Laser Institute and Medical Clinic, Irvine, California 92612,; Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, California 92617
| | | | - Kyoko Yokomori
- Department of Biological Chemistry, School of Medicine, University of California, Irvine, California 92697-1700, and.
| | - Jagesh V Shah
- Department of Systems Biology, Harvard Medical School and Renal Division, Brigham and Women's Hospital, Boston, Massachusetts 02115.
| | - Michael W Berns
- Beckman Laser Institute and Medical Clinic, Irvine, California 92612,; Department of Developmental and Cell Biology, School of Biological Sciences, University of California, Irvine, California 92617,; Department of Biomedical Engineering, University of California, Irvine, California 92617,.
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Alili L, Diekmann J, Giesen M, Holtkötter O, Brenneisen P. A drug-induced accelerated senescence (DIAS) is a possibility to study aging in time lapse. AGE (DORDRECHT, NETHERLANDS) 2014; 36:9658. [PMID: 24833306 PMCID: PMC4082584 DOI: 10.1007/s11357-014-9658-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 04/14/2014] [Indexed: 05/28/2023]
Abstract
Currently, the oxidative stress (or free radical) theory of aging is the most popular explanation of how aging occurs at the molecular level. Accordingly, a stress-induced senescence-like phenotype of human dermal fibroblasts can be induced in vitro by the exposure of human diploid fibroblasts to subcytotoxic concentrations of hydrogen peroxide. However, several biomarkers of replicative senescence e.g. cell cycle arrest and enlarged morphology are abrogated 14 days after treatment, indicating that reactive oxygen species (ROS) rather acts as a trigger for short-term senescence (1-3 days) than being responsible for the maintenance of the senescence-like phenotype. Further, DNA-damaging factors are discussed resulting in a permanent senescent cell type. To induce long-term premature senescence and to understand the molecular alterations occurring during the aging process, we analyzed mitomycin C (MMC) as an alkylating DNA-damaging agent and ROS producer. Human dermal fibroblasts (HDF), used as model for skin aging, were exposed to non-cytotoxic concentrations of MMC and analyzed for potential markers of cellular aging, for example enlarged morphology, activity of senescence-associated-ß-galactosidase, cell cycle arrest, increased ROS production and MMP1-activity, which are well-documented for HDF in replicative senescence. Our data show that mitomycin C treatment results in a drug-induced accelerated senescence (DIAS) with long-term expression of senescence markers, demonstrating that a combination of different susceptibility factors, here ROS and DNA alkylation, are necessary to induce a permanent senescent cell type.
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Affiliation(s)
- Lirija Alili
- Institute of Biochemistry & Molecular Biology I, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany,
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32
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McCauley BS, Dang W. Histone methylation and aging: lessons learned from model systems. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:1454-62. [PMID: 24859460 DOI: 10.1016/j.bbagrm.2014.05.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 03/16/2014] [Accepted: 05/13/2014] [Indexed: 01/06/2023]
Abstract
Aging induces myriad cellular and, ultimately, physiological changes that cause a decline in an organism's functional capabilities. Although the aging process and the pathways that regulate it have been extensively studied, only in the last decade have we begun to appreciate that dynamic histone methylation may contribute to this process. In this review, we discuss recent work implicating histone methylation in aging. Loss of certain histone methyltransferases and demethylases changes lifespan in invertebrates, and alterations in histone methylation in aged organisms regulate lifespan and aging phenotypes, including oxidative stress-induced hormesis in yeast, insulin signaling in Caenorhabiditis elegans and mammals, and the senescence-associated secretory phenotype in mammals. In all cases where histone methylation has been shown to impact aging and aging phenotypes, it does so by regulating transcription, suggesting that this is a major mechanism of its action in this context. Histone methylation additionally regulates or is regulated by other cellular pathways that contribute to or combat aging. Given the numerous processes that regulate aging and histone methylation, and are in turn regulated by them, the role of histone methylation in aging is almost certainly underappreciated.
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Affiliation(s)
- Brenna S McCauley
- Huffington Center on Aging, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA.
| | - Weiwei Dang
- Huffington Center on Aging, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA.
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Palanca A, Casafont I, Berciano MT, Lafarga M. Proteasome inhibition induces DNA damage and reorganizes nuclear architecture and protein synthesis machinery in sensory ganglion neurons. Cell Mol Life Sci 2014; 71:1961-75. [PMID: 24061536 PMCID: PMC11113442 DOI: 10.1007/s00018-013-1474-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 09/02/2013] [Accepted: 09/10/2013] [Indexed: 11/24/2022]
Abstract
Bortezomib is a reversible proteasome inhibitor used as an anticancer drug. However, its clinical use is limited since it causes peripheral neurotoxicity. We have used Sprague-Dawley rats as an animal model to investigate the cellular mechanisms affected by both short-term and chronic bortezomib treatments in sensory ganglia neurons. Proteasome inhibition induces dose-dependent alterations in the architecture, positioning, shape and polarity of the neuronal nucleus. It also produces DNA damage without affecting neuronal survival, and severe disruption of the protein synthesis machinery at the central cytoplasm accompanied by decreased expression of the brain-derived neurotrophic factor. As a compensatory or adaptive survival response against proteotoxic stress caused by bortezomib treatment, sensory neurons preserve basal levels of transcriptional activity, up-regulate the expression of proteasome subunit genes, and generate a new cytoplasmic perinuclear domain for protein synthesis. We propose that proteasome activity is crucial for controlling nuclear architecture, DNA repair and the organization of the protein synthesis machinery in sensory neurons. These neurons are primary targets of bortezomib neurotoxicity, for which reason their dysfunction may contribute to the pathogenesis of the bortezomib-induced peripheral neuropathy in treated patients.
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Affiliation(s)
- Ana Palanca
- Department of Anatomy and Cell Biology, Faculty of Medicine and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), University of Cantabria-IFIMAV, Avd. Cardenal Herrera Oria s/n, 39011 Santander, Spain
| | - Iñigo Casafont
- Department of Anatomy and Cell Biology, Faculty of Medicine and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), University of Cantabria-IFIMAV, Avd. Cardenal Herrera Oria s/n, 39011 Santander, Spain
| | - María T. Berciano
- Department of Anatomy and Cell Biology, Faculty of Medicine and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), University of Cantabria-IFIMAV, Avd. Cardenal Herrera Oria s/n, 39011 Santander, Spain
| | - Miguel Lafarga
- Department of Anatomy and Cell Biology, Faculty of Medicine and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), University of Cantabria-IFIMAV, Avd. Cardenal Herrera Oria s/n, 39011 Santander, Spain
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Hennig J, McShane MP, Cordes N, Eke I. APPL proteins modulate DNA repair and radiation survival of pancreatic carcinoma cells by regulating ATM. Cell Death Dis 2014; 5:e1199. [PMID: 24763056 PMCID: PMC4001316 DOI: 10.1038/cddis.2014.167] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 03/17/2014] [Accepted: 03/18/2014] [Indexed: 11/12/2022]
Abstract
Despite intensive multimodal therapies, the overall survival rate of patients with ductal adenocarcinoma of the pancreas is still poor. The chemo- and radioresistance mechanisms of this tumor entity remain to be determined in order to develop novel treatment strategies. In cancer, endocytosis and membrane trafficking proteins are known to be utilized and they also critically regulate essential cell functions like survival and proliferation. On the basis of these data, we evaluated the role of the endosomal proteins adaptor proteins containing pleckstrin homology domain, phosphotyrosine binding domain and a leucine zipper motif (APPL)1 and 2 for the radioresistance of pancreatic carcinoma cells. Here, we show that APPL2 expression in pancreatic cancer cells is upregulated after irradiation and that depletion of APPL proteins by small interfering RNA (siRNA) significantly reduced radiation survival in parallel to impairing DNA double strand break (DSB) repair. In addition, APPL knockdown diminished radiogenic hyperphosphorylation of ataxia telangiectasia mutated (ATM). Activated ATM and APPL1 were also shown to interact after irradiation, suggesting that APPL has a more direct role in the phosphorylation of ATM. Double targeting of APPL proteins and ATM caused similar radiosensitization and concomitant DSB repair perturbation to that observed after depletion of single proteins, indicating that ATM is the central modulator of APPL-mediated effects on radiosensitivity and DNA repair. These data strongly suggest that endosomal APPL proteins contribute to the DNA damage response. Whether targeting of APPL proteins is beneficial for the survival of patients with pancreatic adenocarcinoma remains to be elucidated.
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Affiliation(s)
- J Hennig
- OncoRay—National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, 01307 Dresden, Germany
| | - M P McShane
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - N Cordes
- OncoRay—National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, 01307 Dresden, Germany
| | - I Eke
- OncoRay—National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden-Rossendorf, 01307 Dresden, Germany
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35
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Kumar V, Alt FW, Oksenych V. Reprint of "Functional overlaps between XLF and the ATM-dependent DNA double strand break response". DNA Repair (Amst) 2014; 17:52-63. [PMID: 24767946 DOI: 10.1016/j.dnarep.2014.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/14/2014] [Accepted: 01/24/2014] [Indexed: 02/08/2023]
Abstract
Developing B and T lymphocytes generate programmed DNA double strand breaks (DSBs) during the V(D)J recombination process that assembles exons that encode the antigen-binding variable regions of antibodies. In addition, mature B lymphocytes generate programmed DSBs during the immunoglobulin heavy chain (IgH) class switch recombination (CSR) process that allows expression of different antibody heavy chain constant regions that provide different effector functions. During both V(D)J recombination and CSR, DSB intermediates are sensed by the ATM-dependent DSB response (DSBR) pathway, which also contributes to their joining via classical non-homologous end-joining (C-NHEJ). The precise nature of the interplay between the DSBR and C-NHEJ pathways in the context of DSB repair via C-NHEJ remains under investigation. Recent studies have shown that the XLF C-NHEJ factor has functional redundancy with several members of the ATM-dependent DSBR pathway in C-NHEJ, highlighting unappreciated major roles for both XLF as well as the DSBR in V(D)J recombination, CSR and C-NHEJ in general. In this review, we discuss current knowledge of the mechanisms that contribute to the repair of DSBs generated during B lymphocyte development and activation with a focus on potential functionally redundant roles of XLF and ATM-dependent DSBR factors.
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Affiliation(s)
- Vipul Kumar
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02115, United States
| | - Frederick W Alt
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02115, United States.
| | - Valentyn Oksenych
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02115, United States.
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Cytolethal distending toxin (CDT) is a radiomimetic agent and induces persistent levels of DNA double-strand breaks in human fibroblasts. DNA Repair (Amst) 2014; 18:31-43. [PMID: 24680221 DOI: 10.1016/j.dnarep.2014.03.002] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Revised: 02/07/2014] [Accepted: 03/03/2014] [Indexed: 11/22/2022]
Abstract
Cytolethal distending toxin (CDT) is a unique genotoxin produced by several pathogenic bacteria. The tripartite protein toxin is internalized into mammalian cells via endocytosis followed by retrograde transport to the ER. Upon translocation into the nucleus, CDT catalyzes the formation of DNA double-strand breaks (DSBs) due to its intrinsic endonuclease activity. In the present study, we compared the DNA damage response (DDR) in human fibroblasts triggered by recombinant CDT to that of ionizing radiation (IR), a well-known DSB inducer. Furthermore, we dissected the pathways involved in the detection and repair of CDT-induced DNA lesions. qRT-PCR array-based mRNA and western blot analyses showed a partial overlap in the DDR pattern elicited by CDT and IR, with strong activation of both the ATM-Chk2 and the ATR-Chk1 axis. In line with its in vitro DNase I-like activity on plasmid DNA, neutral and alkaline Comet assay revealed predominant induction of DSBs in CDT-treated fibroblasts, whereas irradiation of cells generated higher amounts of SSBs and alkali-labile sites. Using confocal microscopy, the dynamics of the DSB surrogate marker γ-H2AX was monitored after pulse treatment with CDT or IR. In contrast to the fast induction and disappearance of γ-H2AX-foci observed in irradiated cells, the number of γ-H2AX-foci induced by CDT were formed with a delay and persisted. 53BP1 foci were also generated following CDT treatment and co-localized with γ-H2AX foci. We further demonstrated that ATM-deficient cells are very sensitive to CDT-induced DNA damage as reflected by increased cell death rates with concomitant cleavage of caspase-3 and PARP-1. Finally, we provided novel evidence that both homologous recombination (HR) and non-homologous end joining (NHEJ) protect against CDT-elicited DSBs. In conclusion, the findings suggest that CDT functions as a radiomimetic agent and, therefore, is an attractive tool for selectively inducing persistent levels of DSBs and unveiling the associated cellular responses.
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37
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Becker A, Durante M, Taucher-Scholz G, Jakob B. ATM alters the otherwise robust chromatin mobility at sites of DNA double-strand breaks (DSBs) in human cells. PLoS One 2014; 9:e92640. [PMID: 24651490 PMCID: PMC3961414 DOI: 10.1371/journal.pone.0092640] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Accepted: 02/23/2014] [Indexed: 11/18/2022] Open
Abstract
Ionizing radiation induces DNA double strand breaks (DSBs) which can lead to the formation of chromosome rearrangements through error prone repair. In mammalian cells the positional stability of chromatin contributes to the maintenance of genome integrity. DSBs exhibit only a small, submicron scale diffusive mobility, but a slight increase in the mobility of chromatin domains by the induction of DSBs might influence repair fidelity and the formation of translocations. The radiation-induced local DNA decondensation in the vicinity of DSBs is one factor potentially enhancing the mobility of DSB-containing chromatin domains. Therefore in this study we focus on the influence of different chromatin modifying proteins, known to be activated by the DNA damage response, on the mobility of DSBs. IRIF (ionizing radiation induced foci) in U2OS cells stably expressing 53BP1-GFP were used as a surrogate marker of DSBs. Low angle charged particle irradiation, known to trigger a pronounced DNA decondensation, was used for the defined induction of linear tracks of IRIF. Our results show that movement of IRIF is independent of the investigated chromatin modifying proteins like ACF1 or PARP1 and PARG. Also depletion of proteins that tether DNA strands like MRE11 and cohesin did not alter IRIF dynamics significantly. Inhibition of ATM, a key component of DNA damage response signaling, resulted in a pronounced confinement of DSB mobility, which might be attributed to a diminished radiation induced decondensation. This confinement following ATM inhibition was confirmed using X-rays, proving that this effect is not restricted to densely ionizing radiation. In conclusion, repair sites of DSBs exhibit a limited mobility on a small spatial scale that is mainly unaffected by depletion of single remodeling or DNA tethering proteins. However, it relies on functional ATM kinase which is considered to influence the chromatin structure after irradiation.
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Affiliation(s)
- Annabelle Becker
- GSI, Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - Marco Durante
- GSI, Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
- Technical University of Darmstadt, Darmstadt, Germany
| | - Gisela Taucher-Scholz
- GSI, Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
- Technical University of Darmstadt, Darmstadt, Germany
| | - Burkhard Jakob
- GSI, Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
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38
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Wang Z, Yin H, Lv L, Feng Y, Chen S, Liang J, Huang Y, Jiang X, Jiang H, Bukhari I, Wu L, Cooke HJ, Shi Q. Unrepaired DNA damage facilitates elimination of uniparental chromosomes in interspecific hybrid cells. Cell Cycle 2014; 13:1345-56. [PMID: 24608870 DOI: 10.4161/cc.28296] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Elimination of uniparental chromosomes occurs frequently in interspecific hybrid cells. For example, human chromosomes are always eliminated during clone formation when human cells are fused with mouse cells. However, the underlying mechanisms are still elusive. Here, we show that the elimination of human chromosomes in human-mouse hybrid cells is accompanied by continued cell division at the presence of DNA damage on human chromosomes. Deficiency in DNA damage repair on human chromosomes occurs after cell fusion. Furthermore, increasing the level of DNA damage on human chromosomes by irradiation accelerates human chromosome loss in hybrid cells. Our results indicate that the elimination of human chromosomes in human-mouse hybrid cells results from unrepaired DNA damage on human chromosomes. We therefore provide a novel mechanism underlying chromosome instability which may facilitate the understanding of carcinogenesis.
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Affiliation(s)
- Zheng Wang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Hao Yin
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Lei Lv
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Yingying Feng
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Shaopeng Chen
- Hefei Institutes of Physical Science, Chinese Academy of Sciences; Hefei, China
| | - Junting Liang
- Hefei Institutes of Physical Science, Chinese Academy of Sciences; Hefei, China
| | - Yun Huang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Xiaohua Jiang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Hanwei Jiang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Ihtisham Bukhari
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China
| | - Lijun Wu
- Hefei Institutes of Physical Science, Chinese Academy of Sciences; Hefei, China
| | - Howard J Cooke
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China; MRC Human Genetics Unit and Institute of Genetics and Molecular Medicine; University of Edinburgh; Western General Hospital; Edinburgh, UK
| | - Qinghua Shi
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences; University of Science and Technology of China; Hefei, China; Hefei Institutes of Physical Science, Chinese Academy of Sciences; Hefei, China
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Kumar V, Alt FW, Oksenych V. Functional overlaps between XLF and the ATM-dependent DNA double strand break response. DNA Repair (Amst) 2014; 16:11-22. [PMID: 24674624 DOI: 10.1016/j.dnarep.2014.01.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/14/2014] [Accepted: 01/24/2014] [Indexed: 11/27/2022]
Abstract
Developing B and T lymphocytes generate programmed DNA double strand breaks (DSBs) during the V(D)J recombination process that assembles exons that encode the antigen-binding variable regions of antibodies. In addition, mature B lymphocytes generate programmed DSBs during the immunoglobulin heavy chain (IgH) class switch recombination (CSR) process that allows expression of different antibody heavy chain constant regions that provide different effector functions. During both V(D)J recombination and CSR, DSB intermediates are sensed by the ATM-dependent DSB response (DSBR) pathway, which also contributes to their joining via classical non-homologous end-joining (C-NHEJ). The precise nature of the interplay between the DSBR and C-NHEJ pathways in the context of DSB repair via C-NHEJ remains under investigation. Recent studies have shown that the XLF C-NHEJ factor has functional redundancy with several members of the ATM-dependent DSBR pathway in C-NHEJ, highlighting unappreciated major roles for both XLF as well as the DSBR in V(D)J recombination, CSR and C-NHEJ in general. In this review, we discuss current knowledge of the mechanisms that contribute to the repair of DSBs generated during B lymphocyte development and activation with a focus on potential functionally redundant roles of XLF and ATM-dependent DSBR factors.
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Affiliation(s)
- Vipul Kumar
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02115, United States
| | - Frederick W Alt
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02115, United States.
| | - Valentyn Oksenych
- Howard Hughes Medical Institute, Program in Cellular and Molecular Medicine, Boston Children's Hospital, Department of Genetics, Harvard Medical School, Boston, MA 02115, United States.
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40
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Nguyen TA, Menendez D, Resnick MA, Anderson CW. Mutant TP53 posttranslational modifications: challenges and opportunities. Hum Mutat 2014; 35:738-55. [PMID: 24395704 DOI: 10.1002/humu.22506] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 01/02/2014] [Indexed: 12/13/2022]
Abstract
The wild-type (WT) human p53 (TP53) tumor suppressor can be posttranslationally modified at over 60 of its 393 residues. These modifications contribute to changes in TP53 stability and in its activity as a transcription factor in response to a wide variety of intrinsic and extrinsic stresses in part through regulation of protein-protein and protein-DNA interactions. The TP53 gene frequently is mutated in cancers, and in contrast to most other tumor suppressors, the mutations are mostly missense often resulting in the accumulation of mutant (MUT) protein, which may have novel or altered functions. Most MUT TP53s can be posttranslationally modified at the same residues as in WT TP53. Strikingly, however, codons for modified residues are rarely mutated in human tumors, suggesting that TP53 modifications are not essential for tumor suppression activity. Nevertheless, these modifications might alter MUT TP53 activity and contribute to a gain-of-function leading to increased metastasis and tumor progression. Furthermore, many of the signal transduction pathways that result in TP53 modifications are altered or disrupted in cancers. Understanding the signaling pathways that result in TP53 modification and the functions of these modifications in both WT TP53 and its many MUT forms may contribute to more effective cancer therapies.
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Affiliation(s)
- Thuy-Ai Nguyen
- Chromosome Stability Section, Laboratory of Molecular Genetics, National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina
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41
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Effects of antioxidants on the quality and genomic stability of induced pluripotent stem cells. Sci Rep 2014; 4:3779. [PMID: 24445363 PMCID: PMC3896906 DOI: 10.1038/srep03779] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 12/27/2013] [Indexed: 01/18/2023] Open
Abstract
Effects of antioxidants on the quality and genomic stability of induced pluripotent stem (iPS) cells were investigated with two human iPS cell lines (201B7 and 253G1). Cells used in this study were expanded from a single colony of each cell line with the addition of proprietary antioxidant supplement or homemade antioxidant cocktail in medium, and maintained in parallel for 2 months. The cells grew well in all culture conditions and kept “stemness”. Although antioxidants modestly decreased the levels of intracellular reactive oxygen species, there were no differences in the expression of 53BP1 and pATM, two critical molecules related with DNA damage and repair, under various culture conditions. CGH analysis showed that the events of genetic aberrations were decreased only in the 253G1 iPS cells with the addition of homemade antioxidant cocktail. Long-term culture will be necessary to confirm whether low dose antioxidants improve the quality and genomic stability of iPS cells.
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42
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Inhibition of ERN1 modifies the hypoxic regulation of the expression of TP53-related genes in U87 glioma cells. ENDOPLASMIC RETICULUM STRESS IN DISEASES 2014. [DOI: 10.2478/ersc-2014-0001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
AbstractInhibition of ERN1 (endoplasmic reticulum to nuclei 1), the major signalling pathway of endoplasmic reticulum stress, significantly decreases tumor growth. We have studied the expression of tumor protein 53 (TP53)- related genes such as TOPORS (topoisomerase I binding, arginine/serine-rich, E3 ubiquitin protein ligase), TP53BP1 (TP53 binding protein 1), TP53BP2, SESN1 (sestrin 1), NME6 (non-metastatic cells 6), and ZMAT3 (zinc finger, Matrin-type 3) in glioma cells expressing dominantnegative ERN1 under baseline and hypoxic conditions. We demonstrated that inhibition of ERN1 function in U87 glioma cells resulted in increased expression of RYBP, TP53BP2, and SESN1 genes, but decreased expression of TP53BP1, TOPORS, NME6, and ZMAT3 genes. Moreover, inhibition of ERN1 affected hypoxia-mediated changes in expression of TP53-related genes and their magnitude. Indeed, hypoxia has no effect on expression of TP53BP1 and SESN1 in control cells, while resulted in increased expression of these genes in cells with inhibited ERN1 function. Magnitude of hypoxia-mediated changes in expression levels of RYBP and TP53BP2 was gene specific and more robust in the case of TP53BP2. Hypoxiamediated decrease in expression levels of TOPORS was more prominent if ERN1 was inhibited. Present study demonstrates that fine-tuning of the expression of TP53- associated genes depends upon endoplasmic reticulum stress signaling under normal and hypoxic conditions. Inhibition of ERN1 branch of endoplasmic reticulum stress response correlates with deregulation of p53 signaling and slower tumor growth.
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43
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Mariotti LG, Pirovano G, Savage KI, Ghita M, Ottolenghi A, Prise KM, Schettino G. Use of the γ-H2AX assay to investigate DNA repair dynamics following multiple radiation exposures. PLoS One 2013; 8:e79541. [PMID: 24312182 DOI: 10.1371/journal.pone.0079541e.0079541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 09/23/2013] [Indexed: 05/25/2023] Open
Abstract
Radiation therapy is one of the most common and effective strategies used to treat cancer. The irradiation is usually performed with a fractionated scheme, where the dose required to kill tumour cells is given in several sessions, spaced by specific time intervals, to allow healthy tissue recovery. In this work, we examined the DNA repair dynamics of cells exposed to radiation delivered in fractions, by assessing the response of histone-2AX (H2AX) phosphorylation (γ-H2AX), a marker of DNA double strand breaks. γ-H2AX foci induction and disappearance were monitored following split dose irradiation experiments in which time interval between exposure and dose were varied. Experimental data have been coupled to an analytical theoretical model, in order to quantify key parameters involved in the foci induction process. Induction of γ-H2AX foci was found to be affected by the initial radiation exposure with a smaller number of foci induced by subsequent exposures. This was compared to chromatin relaxation and cell survival. The time needed for full recovery of γ-H2AX foci induction was quantified (12 hours) and the 1:1 relationship between radiation induced DNA double strand breaks and foci numbers was critically assessed in the multiple irradiation scenarios.
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Affiliation(s)
- Luca G Mariotti
- Dipartimento di Fisica, Università degli studi di Pavia, Pavia, Italy ; Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Pavia, Italy
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44
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Mariotti LG, Pirovano G, Savage KI, Ghita M, Ottolenghi A, Prise KM, Schettino G. Use of the γ-H2AX assay to investigate DNA repair dynamics following multiple radiation exposures. PLoS One 2013; 8:e79541. [PMID: 24312182 PMCID: PMC3843657 DOI: 10.1371/journal.pone.0079541] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 09/23/2013] [Indexed: 11/18/2022] Open
Abstract
Radiation therapy is one of the most common and effective strategies used to treat cancer. The irradiation is usually performed with a fractionated scheme, where the dose required to kill tumour cells is given in several sessions, spaced by specific time intervals, to allow healthy tissue recovery. In this work, we examined the DNA repair dynamics of cells exposed to radiation delivered in fractions, by assessing the response of histone-2AX (H2AX) phosphorylation (γ-H2AX), a marker of DNA double strand breaks. γ-H2AX foci induction and disappearance were monitored following split dose irradiation experiments in which time interval between exposure and dose were varied. Experimental data have been coupled to an analytical theoretical model, in order to quantify key parameters involved in the foci induction process. Induction of γ-H2AX foci was found to be affected by the initial radiation exposure with a smaller number of foci induced by subsequent exposures. This was compared to chromatin relaxation and cell survival. The time needed for full recovery of γ-H2AX foci induction was quantified (12 hours) and the 1:1 relationship between radiation induced DNA double strand breaks and foci numbers was critically assessed in the multiple irradiation scenarios.
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Affiliation(s)
- Luca G. Mariotti
- Dipartimento di Fisica, Università degli studi di Pavia, Pavia, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Pavia, Italy
| | - Giacomo Pirovano
- Dipartimento di Fisica, Università degli studi di Pavia, Pavia, Italy
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, Belfast, United Kingdom
| | - Kienan I. Savage
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, Belfast, United Kingdom
| | - Mihaela Ghita
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, Belfast, United Kingdom
| | - Andrea Ottolenghi
- Dipartimento di Fisica, Università degli studi di Pavia, Pavia, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Pavia, Pavia, Italy
| | - Kevin M. Prise
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, Belfast, United Kingdom
| | - Giuseppe Schettino
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, Belfast, United Kingdom
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45
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Dey M, Patra S, Su LY, Segall AM. Tumor cell death mediated by peptides that recognize branched intermediates of DNA replication and repair. PLoS One 2013; 8:e78751. [PMID: 24244353 PMCID: PMC3828334 DOI: 10.1371/journal.pone.0078751] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 09/20/2013] [Indexed: 12/15/2022] Open
Abstract
Effective treatments for cancer are still needed, both for cancers that do not respond well to current therapeutics and for cancers that become resistant to available treatments. Herein we investigated the effect of a structure-selective d-amino acid peptide wrwycr that binds replication fork mimics and Holliday Junction (HJs) intermediates of homologous recombination (HR) in vitro, and inhibits their resolution by HJ-processing enzymes. We predicted that treating cells with HJ-binding compounds would lead to accumulation of DNA damage. As cells repair endogenous or exogenous DNA damage, collapsed replication forks and HJ intermediates will accumulate and serve as targets for the HJ-binding peptides. Inhibiting junction resolution will lead to further accumulation of DNA breaks, eventually resulting in amplification of the damage and causing cell death. Both peptide wrwycr and the related wrwyrggrywrw entered cancer cells and reduced cell survival in a dose- and time-dependent manner. Early markers for DNA damage, γH2AX foci and 53BP1 foci, increased with dose and/or time exposure to the peptides. DNA breaks persisted at least 48 h, and both checkpoint proteins Chk1 and Chk2 were activated. The passage of the cells from S to G2/M was blocked even after 72 h. Apoptosis, however, was not induced in either HeLa or PC3 cells. Based on colony-forming assays, about 35% peptide-induced cytotoxicity was irreversible. Finally, sublethal doses of peptide wrwycr (50–100 µM) in conjunction with sublethal doses of several DNA damaging agents (etoposide, doxorubicin, and HU) reduced cell survival at least additively and sometimes synergistically. Taken together, the results suggest that the peptides merit further investigation as proof-of-principle molecules for a new class of anti-cancer therapeutics, in particular in combination with other DNA damaging therapies.
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Affiliation(s)
- Mamon Dey
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
| | - Sukanya Patra
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
| | - Leo Y. Su
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
| | - Anca M. Segall
- Department of Biology and Center for Microbial Sciences, San Diego State University, San Diego, California, United States of America
- * E-mail:
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46
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Peripheral subnuclear positioning suppresses Tcrb recombination and segregates Tcrb alleles from RAG2. Proc Natl Acad Sci U S A 2013; 110:E4628-37. [PMID: 24218622 DOI: 10.1073/pnas.1310846110] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Allelic exclusion requires that the two alleles at antigen-receptor loci attempt to recombine variable (V), diversity (D), and joining (J) gene segments [V(D)J recombination] asynchronously in nuclei of developing lymphocytes. It previously was shown that T-cell receptor β (Tcrb) alleles frequently and stochastically associate with the nuclear lamina and pericentromeric heterochromatin in CD4(-)CD8(-) thymocytes. Moreover, rearranged alleles were underrepresented at these locations. Here we used 3D immunofluorescence in situ hybridization to identify recently rearranged Tcrb alleles based on the accumulation of the DNA-repair protein 53BP1. We found that Tcrb alleles recombine asynchronously in double-negative thymocytes and that V(D)J recombination is suppressed on peripheral as compared with central Tcrb alleles. Moreover, the recombination events that did take place at the nuclear periphery preferentially occurred on Tcrb alleles that were partially dissociated from the nuclear lamina. To understand better the mechanism by which V(D)J recombination is suppressed at the nuclear periphery, we evaluated the subnuclear distribution of recombination-activating gene 2 (RAG2) protein. We found that RAG2 abundance was reduced at the nuclear periphery. Moreover, RAG2 was distributed differently from RNA polymerase II and histone H3K4 trimethylation. Our data suggest that the nuclear periphery suppresses V(D)J recombination, at least in part, by segregating Tcrb alleles from RAG proteins.
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47
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Nagy A, Hollingsworth JA, Hu B, Steinbrück A, Stark PC, Rios Valdez C, Vuyisich M, Stewart MH, Atha DH, Nelson BC, Iyer R. Functionalization-dependent induction of cellular survival pathways by CdSe quantum dots in primary normal human bronchial epithelial cells. ACS NANO 2013; 7:8397-411. [PMID: 24007210 DOI: 10.1021/nn305532k] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Quantum dots (QDs) are semiconductor nanocrystals exhibiting unique optical properties that can be exploited for many practical applications ranging from photovoltaics to biomedical imaging and drug delivery. A significant number of studies have alluded to the cytotoxic potential of these materials, implicating Cd-leaching as the causal factor. Here, we investigated the role of heavy metals in biological responses and the potential of CdSe-induced genotoxicity. Our results indicate that, while negatively charged QDs are relatively noncytotoxic compared to positively charged QDs, the same does not hold true for their genotoxic potential. Keeping QD core composition and size constant, 3 nm CdSe QD cores were functionalized with mercaptopropionic acid (MPA) or cysteamine (CYST), resulting in negatively or positively charged surfaces, respectively. CYST-QDs were found to induce significant cytotoxicity accompanied by DNA strand breakage. However, MPA-QDs, even in the absence of cytotoxicity and reactive oxygen species formation, also induced a high number of DNA strand breaks. QD-induced DNA damage was confirmed by identifying the presence of p53 binding protein 1 (53BP1) in the nuclei of exposed cells and subsequent diminishment of p53 from cytoplasmic cellular extracts. Further, high-throughput real-time PCR analyses revealed upregulation of DNA damage and response genes and several proinflammatory cytokine genes. Most importantly, transcriptome sequencing revealed upregulation of the metallothionein family of genes in cells exposed to MPA-QDs but not CYST-QDs. These data indicate that cytotoxic assays must be supplemented with genotoxic analyses to better understand cellular responses and the full impact of nanoparticle exposure when making recommendations with regard to risk assessment.
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Affiliation(s)
- Amber Nagy
- Bioscience Division, ‡Center for Integrated Nanotechnologies, Materials Physics & Applications Division, and §Chemical Diagnostics and Engineering, Los Alamos National Laboratory , Los Alamos, New Mexico 87545, United States
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48
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Zimmermann M, de Lange T. 53BP1: pro choice in DNA repair. Trends Cell Biol 2013; 24:108-17. [PMID: 24094932 DOI: 10.1016/j.tcb.2013.09.003] [Citation(s) in RCA: 275] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 09/04/2013] [Accepted: 09/05/2013] [Indexed: 12/16/2022]
Abstract
The DNA damage response factor 53BP1 functions at the intersection of two major double strand break (DSB) repair pathways--promoting nonhomologous end-joining (NHEJ) and inhibiting homology-directed repair (HDR)--and integrates cellular inputs to ensure their timely execution in the proper cellular contexts. Recent work has revealed that 53BP1 controls 5' end resection at DNA ends, mediates synapsis of DNA ends, promotes the mobility of damaged chromatin, improves DSB repair in heterochromatic regions, and contributes to lethal mis-repair of DSBs in BRCA1-deficient cells. Here we review these aspects of 53BP1 and discuss new data revealing how 53BP1 is loaded onto chromatin and uses its interacting factors Rif1 and PTIP to promote NHEJ and inhibit HDR.
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Affiliation(s)
- Michal Zimmermann
- Laboratory for Cell Biology and Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA; Central European Institute of Technology and Faculty of Science, Masaryk University, Brno, Czech Republic
| | - Titia de Lange
- Laboratory for Cell Biology and Genetics, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA.
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49
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Studying the cerebellar DNA damage response in the tissue culture dish. Mech Ageing Dev 2013; 134:496-505. [DOI: 10.1016/j.mad.2013.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/29/2013] [Accepted: 04/01/2013] [Indexed: 11/30/2022]
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50
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Lu R, Wang GG. Tudor: a versatile family of histone methylation 'readers'. Trends Biochem Sci 2013; 38:546-55. [PMID: 24035451 DOI: 10.1016/j.tibs.2013.08.002] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 08/07/2013] [Accepted: 08/08/2013] [Indexed: 12/28/2022]
Abstract
The Tudor domain comprises a family of motifs that mediate protein-protein interactions required for various DNA-templated biological processes. Emerging evidence demonstrates a versatility of the Tudor family domains by identifying their specific interactions to a wide variety of histone methylation marks. Here, we discuss novel functions of a number of Tudor-containing proteins [including Jumonji domain-containing 2A (JMJD2A), p53-binding protein 1 (53BP1), SAGA-associated factor 29 (SGF29), Spindlin1, ubiquitin-like with PHD and RING finger domains 1 (UHRF1), PHD finger protein 1 (PHF1), PHD finger protein 19 (PHF19), and SAWADEE homeodomain homolog 1 (SHH1)] in 'reading' unique methylation events on histones in order to facilitate DNA damage repair or regulate transcription. This review covers our recent understanding of the molecular bases for histone-Tudor interactions and their biological outcomes. As deregulation of Tudor-containing proteins is associated with certain human disorders, pharmacological targeting of Tudor interactions could provide new avenues for therapeutic intervention.
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Affiliation(s)
- Rui Lu
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
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