1
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Mitra D, Pande S, Chatterji A. Topology-driven spatial organization of ring polymers under confinement. Phys Rev E 2022; 106:054502. [PMID: 36559479 DOI: 10.1103/physreve.106.054502] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/12/2022] [Indexed: 11/19/2022]
Abstract
Entropic repulsion between DNA ring polymers under confinement is a key mechanism governing the spatial segregation of bacterial DNA before cell division. Here we establish that "internal" loops within a modified-ring polymer architecture enhance entropic repulsion between two overlapping polymers confined in a cylinder. Interestingly, they also induce entropy-driven spatial organization of polymer segments as seen in vivo. Here we design polymers of different architectures in our simulations by introducing a minimal number of cross-links between specific monomers along the ring-polymer contour. The cross-links are likely induced by various bridging proteins inside living cells. We investigate the segregation of two polymers with modified topologies confined in a cylinder, which initially had spatially overlapping configurations. This helps us to identify the architectures that lead to higher success rates of segregation. We also establish the mechanism that leads to localization of specific polymer segments. We use the blob model to provide a theoretical understanding of why certain architectures lead to enhanced entropic repulsive forces between the polymers. Lastly, we establish a correspondence between the organizational patterns of the chromosome of the C.crescentus bacterium and our results for a specifically designed polymer architecture. However, the principles outlined here pertaining to the organization of polymeric segments are applicable to both synthetic and biological polymers.
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2
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Hemagirri M, Sasidharan S. Biology of aging: Oxidative stress and RNA oxidation. Mol Biol Rep 2022; 49:5089-5105. [PMID: 35449319 DOI: 10.1007/s11033-022-07219-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/27/2022] [Accepted: 02/01/2022] [Indexed: 01/10/2023]
Abstract
The prevalence of aged people has increased rapidly in recent years and brings profound demographic changes worldwide. The multi-level progression of aging occurs at diverse stages of complexity, from cell to organ systems and eventually to the human as a whole. The cellular and molecular damages are usually regulated by the cells; repair or degrade mechanisms. However, these mechanisms are not entirely functional; their effectiveness decreases with age due to influence from endogenous sources like oxidative stress, which all contribute to the aging process. The hunt for novel strategies to increase the man's longevity since ancient times needs better understandings of the biology of aging, oxidative stress, and their roles in RNA oxidation. The critical goal in developing new strategies to increase the man's longevity is to compile the novel developed knowledge on human aging into a single picture, preferably able to understand the biology of aging and the contributing factors. This review discusses the biology of aging, oxidative stress, and their roles in RNA oxidation, leading to aging in humans.
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Affiliation(s)
- Manisekaran Hemagirri
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, 11800 USM, Pulau Pinang, Malaysia
| | - Sreenivasan Sasidharan
- Institute for Research in Molecular Medicine, Universiti Sains Malaysia, 11800 USM, Pulau Pinang, Malaysia.
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3
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Das R, Sakaue T, Shivashankar GV, Prost J, Hiraiwa T. How enzymatic activity is involved in chromatin organization. eLife 2022; 11:79901. [PMID: 36472500 PMCID: PMC9810329 DOI: 10.7554/elife.79901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 12/06/2022] [Indexed: 12/12/2022] Open
Abstract
Spatial organization of chromatin plays a critical role in genome regulation. Previously, various types of affinity mediators and enzymes have been attributed to regulate spatial organization of chromatin from a thermodynamics perspective. However, at the mechanistic level, enzymes act in their unique ways and perturb the chromatin. Here, we construct a polymer physics model following the mechanistic scheme of Topoisomerase-II, an enzyme resolving topological constraints of chromatin, and investigate how it affects interphase chromatin organization. Our computer simulations demonstrate Topoisomerase-II's ability to phase separate chromatin into eu- and heterochromatic regions with a characteristic wall-like organization of the euchromatic regions. We realized that the ability of the euchromatic regions to cross each other due to enzymatic activity of Topoisomerase-II induces this phase separation. This realization is based on the physical fact that partial absence of self-avoiding interaction can induce phase separation of a system into its self-avoiding and non-self-avoiding parts, which we reveal using a mean-field argument. Furthermore, motivated from recent experimental observations, we extend our model to a bidisperse setting and show that the characteristic features of the enzymatic activity-driven phase separation survive there. The existence of these robust characteristic features, even under the non-localized action of the enzyme, highlights the critical role of enzymatic activity in chromatin organization.
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Affiliation(s)
- Rakesh Das
- Mechanobiology Institute, National University of SingaporeSingaporeSingapore
| | - Takahiro Sakaue
- Department of Physics and Mathematics, Aoyama Gakuin UniversityKanagawaJapan
| | - GV Shivashankar
- ETH ZurichZurichSwitzerland,Paul Scherrer InstituteVilligenSwitzerland
| | - Jacques Prost
- Mechanobiology Institute, National University of SingaporeSingaporeSingapore,Laboratoire Physico Chimie Curie, Institut Curie, Paris Science et Lettres Research UniversityParisFrance
| | - Tetsuya Hiraiwa
- Mechanobiology Institute, National University of SingaporeSingaporeSingapore
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4
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Martinez-Garcia M, White CI, Franklin FCH, Sanchez-Moran E. The Role of Topoisomerase II in DNA Repair and Recombination in Arabidopsis thaliana. Int J Mol Sci 2021; 22:13115. [PMID: 34884922 PMCID: PMC8658145 DOI: 10.3390/ijms222313115] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 11/30/2021] [Accepted: 12/01/2021] [Indexed: 11/25/2022] Open
Abstract
DNA entanglements and supercoiling arise frequently during normal DNA metabolism. DNA topoisomerases are highly conserved enzymes that resolve the topological problems that these structures create. Topoisomerase II (TOPII) releases topological stress in DNA by removing DNA supercoils through breaking the two DNA strands, passing a DNA duplex through the break and religating the broken strands. TOPII performs key DNA metabolic roles essential for DNA replication, chromosome condensation, heterochromatin metabolism, telomere disentanglement, centromere decatenation, transmission of crossover (CO) interference, interlock resolution and chromosome segregation in several model organisms. In this study, we reveal the endogenous role of Arabidopsis thaliana TOPII in normal root growth and cell cycle, and mitotic DNA repair via homologous recombination. Additionally, we show that the protein is required for meiotic DSB repair progression, but not for CO formation. We propose that TOPII might promote mitotic HR DNA repair by relieving stress needed for HR strand invasion and D-loop formation.
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Affiliation(s)
| | - Charles I. White
- Génétique, Reproduction et Développement, Faculté de Médecine, UMR CNRS 6293—INSERM U1103—Université Clermont Auvergne, 28 Place Henri Dunant, 63001 Clermont-Ferrand, France;
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5
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Roca J, Dyson S, Segura J, Valdés A, Martínez-García B. Keeping intracellular DNA untangled: A new role for condensin? Bioessays 2021; 44:e2100187. [PMID: 34761394 DOI: 10.1002/bies.202100187] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 10/25/2021] [Accepted: 10/26/2021] [Indexed: 12/25/2022]
Abstract
The DNA-passage activity of topoisomerase II accidentally produces DNA knots and interlinks within and between chromatin fibers. Fortunately, these unwanted DNA entanglements are actively removed by some mechanism. Here we present an outline on DNA knot formation and discuss recent studies that have investigated how intracellular DNA knots are removed. First, although topoisomerase II is able to minimize DNA entanglements in vitro to below equilibrium values, it is unclear whether such capacity performs equally in vivo in chromatinized DNA. Second, DNA supercoiling could bias topoisomerase II to untangle the DNA. However, experimental evidence indicates that transcriptional supercoiling of intracellular DNA boosts knot formation. Last, cohesin and condensin could tighten DNA entanglements via DNA loop extrusion (LE) and force their dissolution by topoisomerase II. Recent observations indicate that condensin activity promotes the removal of DNA knots during interphase and mitosis. This activity might facilitate the spatial organization and dynamics of chromatin.
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Affiliation(s)
- Joaquim Roca
- Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Spain
| | - Silvia Dyson
- Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Spain
| | - Joana Segura
- Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Spain
| | - Antonio Valdés
- Julius Maximilian University of Würzburg, Würzburg, Germany
| | - Belén Martínez-García
- Molecular Biology Institute of Barcelona (IBMB), Spanish National Research Council (CSIC), Barcelona, Spain
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6
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DNA-Topology Simplification by Topoisomerases. Molecules 2021; 26:molecules26113375. [PMID: 34204901 PMCID: PMC8199745 DOI: 10.3390/molecules26113375] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/20/2021] [Accepted: 05/26/2021] [Indexed: 11/17/2022] Open
Abstract
The topological properties of DNA molecules, supercoiling, knotting, and catenation, are intimately connected with essential biological processes, such as gene expression, replication, recombination, and chromosome segregation. Non-trivial DNA topologies present challenges to the molecular machines that process and maintain genomic information, for example, by creating unwanted DNA entanglements. At the same time, topological distortion can facilitate DNA-sequence recognition through localized duplex unwinding and longer-range loop-mediated interactions between the DNA sequences. Topoisomerases are a special class of essential enzymes that homeostatically manage DNA topology through the passage of DNA strands. The activities of these enzymes are generally investigated using circular DNA as a model system, in which case it is possible to directly assay the formation and relaxation of DNA supercoils and the formation/resolution of knots and catenanes. Some topoisomerases use ATP as an energy cofactor, whereas others act in an ATP-independent manner. The free energy of ATP hydrolysis can be used to drive negative and positive supercoiling or to specifically relax DNA topologies to levels below those that are expected at thermodynamic equilibrium. The latter activity, which is known as topology simplification, is thus far exclusively associated with type-II topoisomerases and it can be understood through insight into the detailed non-equilibrium behavior of type-II enzymes. We use a non-equilibrium topological-network approach, which stands in contrast to the equilibrium models that are conventionally used in the DNA-topology field, to gain insights into the rates that govern individual transitions between topological states. We anticipate that our quantitative approach will stimulate experimental work and the theoretical/computational modeling of topoisomerases and similar enzyme systems.
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7
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Li Z, Chen X, Liu Z, Ye W, Li L, Qian L, Ding H, Li P, Aung LHH. Recent Advances: Molecular Mechanism of RNA Oxidation and Its Role in Various Diseases. Front Mol Biosci 2020; 7:184. [PMID: 32850971 PMCID: PMC7413073 DOI: 10.3389/fmolb.2020.00184] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/13/2020] [Indexed: 12/11/2022] Open
Abstract
Compared with the research on DNA damage, there are fewer studies on RNA damage, and the damage mechanism remains mostly unknown. Recent studies have shown that RNA is more vulnerable to damage than DNA when the cells are exposed to endogenous and exogenous insults. RNA injury may participate in a variety of disease occurrence and development. RNA not only has important catalytic functions and other housekeeping functions, it also plays a decisive role in the translation of genetic information and protein biosynthesis. Various kinds of stressors, such as ultraviolet, reactive oxygen species and nitrogen, can cause damage to RNA. It may involve in the development and progression of diseases. In this review, we focused on the relationship between the RNA damage and disease as well as the research progress on the mechanism of RNA damage, which is of great significance for the pathogenesis, diagnosis, and treatment of related diseases.
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Affiliation(s)
- Zhe Li
- Center for Molecular Genetics, Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.,School of Basic Medicine, Qingdao University, Qingdao, China
| | - Xiatian Chen
- Center for Molecular Genetics, Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.,School of Basic Medicine, Qingdao University, Qingdao, China
| | - Ziqian Liu
- Center for Molecular Genetics, Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.,School of Basic Medicine, Qingdao University, Qingdao, China
| | - Wei Ye
- Jiangsu Provincial Engineering Research Center for Biomedical Materials and Advanced Medical Device, Huaiyin Institute of Technology, Huaian, China
| | - Ling Li
- School of Basic Medicine, Qingdao University, Qingdao, China
| | - Lili Qian
- Center for Molecular Genetics, Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Hongyan Ding
- Jiangsu Provincial Engineering Research Center for Biomedical Materials and Advanced Medical Device, Huaiyin Institute of Technology, Huaian, China
| | - Peifeng Li
- Center for Molecular Genetics, Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China
| | - Lynn Htet Htet Aung
- Center for Molecular Genetics, Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, College of Medicine, Qingdao University, Qingdao, China.,School of Basic Medicine, Qingdao University, Qingdao, China
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8
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Ziraldo R, Hanke A, Levene SD. Kinetic pathways of topology simplification by Type-II topoisomerases in knotted supercoiled DNA. Nucleic Acids Res 2019; 47:69-84. [PMID: 30476194 PMCID: PMC6326819 DOI: 10.1093/nar/gky1174] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 11/02/2018] [Indexed: 11/13/2022] Open
Abstract
The topological state of covalently closed, double-stranded DNA is defined by the knot type $K$ and the linking-number difference $\Delta Lk$ relative to unknotted relaxed DNA. DNA topoisomerases are essential enzymes that control the topology of DNA in all cells. In particular, type-II topoisomerases change both $K$ and $\Delta Lk$ by a duplex-strand-passage mechanism and have been shown to simplify the topology of DNA to levels below thermal equilibrium at the expense of ATP hydrolysis. It remains a key question how small enzymes are able to preferentially select strand passages that result in topology simplification in much larger DNA molecules. Using numerical simulations, we consider the non-equilibrium dynamics of transitions between topological states $(K,\Delta Lk)$ in DNA induced by type-II topoisomerases. For a biological process that delivers DNA molecules in a given topological state $(K,\Delta Lk)$ at a constant rate we fully characterize the pathways of topology simplification by type-II topoisomerases in terms of stationary probability distributions and probability currents on the network of topological states $(K,\Delta Lk)$. In particular, we observe that type-II topoisomerase activity is significantly enhanced in DNA molecules that maintain a supercoiled state with constant torsional tension. This is relevant for bacterial cells in which torsional tension is maintained by enzyme-dependent homeostatic mechanisms such as DNA-gyrase activity.
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Affiliation(s)
- Riccardo Ziraldo
- Department of Bioengineering, University of Texas at Dallas, TX 75080, USA
| | - Andreas Hanke
- Department of Physics and Astronomy, University of Texas Rio Grande Valley, Brownsville, TX 78520, USA
| | - Stephen D Levene
- Department of Bioengineering, University of Texas at Dallas, TX 75080, USA.,Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.,Department of Physics, University of Texas at Dallas, Richardson, TX 75080, USA
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9
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Marko JF, De Los Rios P, Barducci A, Gruber S. DNA-segment-capture model for loop extrusion by structural maintenance of chromosome (SMC) protein complexes. Nucleic Acids Res 2019; 47:6956-6972. [PMID: 31175837 PMCID: PMC6649773 DOI: 10.1093/nar/gkz497] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 05/20/2019] [Accepted: 06/06/2019] [Indexed: 01/08/2023] Open
Abstract
Cells possess remarkable control of the folding and entanglement topology of long and flexible chromosomal DNA molecules. It is thought that structural maintenance of chromosome (SMC) protein complexes play a crucial role in this, by organizing long DNAs into series of loops. Experimental data suggest that SMC complexes are able to translocate on DNA, as well as pull out lengths of DNA via a 'loop extrusion' process. We describe a Brownian loop-capture-ratchet model for translocation and loop extrusion based on known structural, catalytic, and DNA-binding properties of the Bacillus subtilis SMC complex. Our model provides an example of a new class of molecular motor where large conformational fluctuations of the motor 'track'-in this case DNA-are involved in the basic translocation process. Quantitative analysis of our model leads to a series of predictions for the motor properties of SMC complexes, most strikingly a strong dependence of SMC translocation velocity and step size on tension in the DNA track that it is moving along, with 'stalling' occuring at subpiconewton tensions. We discuss how the same mechanism might be used by structurally related SMC complexes (Escherichia coli MukBEF and eukaryote condensin, cohesin and SMC5/6) to organize genomic DNA.
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Affiliation(s)
- John F Marko
- Department of Molecular Biosciences and Department of Physics & Astronomy, Northwestern University, Evanston, IL 60208, USA
| | - Paolo De Los Rios
- Laboratory of Statistical Biophysics, Institute of Physics, School of Basic Sciences and Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne - EPFL, 1015 Lausanne, Switzerland
| | - Alessandro Barducci
- Centre de Biochimie Structurale, INSERM, CNRS, Université de Montpellier, 34090 Montpellier, France
| | - Stephan Gruber
- Départment de Microbiologie Fondamentale, Université de Lausanne, 1015 Lausanne, Switzerland
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10
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Bergant K, Janežič M, Valjavec K, Sosič I, Pajk S, Štampar M, Žegura B, Gobec S, Filipič M, Perdih A. Structure-guided optimization of 4,6-substituted-1,3,5-triazin-2(1H)-ones as catalytic inhibitors of human DNA topoisomerase IIα. Eur J Med Chem 2019; 175:330-348. [PMID: 31096154 DOI: 10.1016/j.ejmech.2019.04.055] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 04/19/2019] [Indexed: 01/03/2023]
Abstract
Human DNA topoisomerases represent one of the key targets of modern chemotherapy. An emerging group of catalytic inhibitors of human DNA topoisomerase IIα comprises a new paradigm directed to circumvent the known limitations of topoisomerase II poisons such as cardiotoxicity and induction of secondary tumors. In our previous studies, 4,6-substituted-1,3,5-triazin-2(1H)-ones were discovered as catalytic inhibitors of topo IIα. Here, we report the results of our efforts to optimize several properties of the initial chemical series that did not exhibit cytotoxicity on cancer cell lines. Using an optimized synthetic route, a focused chemical library was designed aimed at further functionalizing substituents at the position 4 of the 1,3,5-triazin-2(1H)-one scaffold to enable additional interactions with the topo IIα ATP binding site. After virtual screening, selected 36 analogues were synthesized and experimentally evaluated for human topo IIα inhibition. The optimized series displayed improved inhibition of topo IIα over the initial series and the catalytic mode of inhibition was confirmed for the selected active compounds. The optimized series also showed cytotoxicity against HepG2 and MCF-7 cell lines and did not induce double-strand breaks, thus displaying a mechanism of action that differs from the topo II poisons on the cellular level. The new series represents a new step in the development of the 4,6-substituted-1,3,5-triazin-2(1H)-one class towards novel efficient anticancer therapies utilizing the catalytic topo IIα inhibition paradigm.
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Affiliation(s)
- Kaja Bergant
- National Institute of Chemistry, Hajdrihova 19, SI 1001, Ljubljana, Slovenia; University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, SI 1000, Ljubljana, Slovenia
| | - Matej Janežič
- Laboratory for Structural Bioinformatics, RIKEN Center for Biosystems Dynamics Research, 1-7-22 Suehiro, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Katja Valjavec
- National Institute of Chemistry, Hajdrihova 19, SI 1001, Ljubljana, Slovenia
| | - Izidor Sosič
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, SI 1000, Ljubljana, Slovenia
| | - Stane Pajk
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, SI 1000, Ljubljana, Slovenia
| | - Martina Štampar
- National Institute of Biology, Department of Genetic Toxicology and Cancer Biology, Večna pot 111, 1000, Ljubljana, Slovenia
| | - Bojana Žegura
- National Institute of Biology, Department of Genetic Toxicology and Cancer Biology, Večna pot 111, 1000, Ljubljana, Slovenia
| | - Stanislav Gobec
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva 7, SI 1000, Ljubljana, Slovenia
| | - Metka Filipič
- National Institute of Biology, Department of Genetic Toxicology and Cancer Biology, Večna pot 111, 1000, Ljubljana, Slovenia
| | - Andrej Perdih
- National Institute of Chemistry, Hajdrihova 19, SI 1001, Ljubljana, Slovenia.
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11
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Karayazi Atici Ö, Urbanska A, Gopinathan SG, Boutillon F, Goffin V, Shemanko CS. ATM Is Required for the Prolactin-Induced HSP90-Mediated Increase in Cellular Viability and Clonogenic Growth After DNA Damage. Endocrinology 2018; 159:907-930. [PMID: 29186352 DOI: 10.1210/en.2017-00652] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 11/21/2017] [Indexed: 02/06/2023]
Abstract
Prolactin (PRL) acts as a survival factor for breast cancer cells, but the PRL signaling pathway and the mechanism are unknown. Previously, we identified the master chaperone, heat shock protein 90 (HSP90) α, as a prolactin-Janus kinase 2 (JAK2)-signal transducer and activator of transcription 5 (STAT5) target gene involved in survival, and here we investigated the role of HSP90 in the mechanism of PRL-induced viability in response to DNA damage. The ataxia-telangiectasia mutated kinase (ATM) protein plays a critical role in the cellular response to double-strand DNA damage. We observed that PRL increased viability of breast cancer cells treated with doxorubicin or etoposide. The increase in cellular resistance is specific to the PRL receptor, because the PRL receptor antagonist, Δ1-9-G129R-hPRL, prevented the increase in viability. Two different HSP90 inhibitors, 17-allylamino-17-demethoxygeldanamycin and BIIB021, reduced the PRL-mediated increase in cell viability of doxorubicin-treated cells and led to a decrease in JAK2, ATM, and phosphorylated ATM protein levels. Inhibitors of JAK2 (G6) and ATM (KU55933) abolished the PRL-mediated increase in cell viability of DNA-damaged cells, supporting the involvement of each, as well as the crosstalk of ATM with the PRL pathway in the context of DNA damage. Drug synergism was detected between the ATM inhibitor (KU55933) and doxorubicin and between the HSP90 inhibitor (BIIB021) and doxorubicin. Short interfering RNA directed against ATM prevented the PRL-mediated increase in cell survival in two-dimensional cell culture, three-dimensional collagen gel cultures, and clonogenic cell survival, after doxorubicin treatment. Our results indicate that ATM contributes to the PRL-JAK2-STAT5-HSP90 pathway in mediating cellular resistance to DNA-damaging agents.
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Affiliation(s)
- Ödül Karayazi Atici
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
- Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, Alberta, Canada
| | - Anna Urbanska
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
- Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, Alberta, Canada
| | - Sesha Gopal Gopinathan
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
- Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, Alberta, Canada
| | - Florence Boutillon
- Inserm U1151, Institut Necker Enfants Malades, Team "PRL/GH Pathophysiology," Faculty of Medicine Paris Descartes, Sorbonne Paris Cité, Paris cedex 14, France
| | - Vincent Goffin
- Inserm U1151, Institut Necker Enfants Malades, Team "PRL/GH Pathophysiology," Faculty of Medicine Paris Descartes, Sorbonne Paris Cité, Paris cedex 14, France
| | - Carrie S Shemanko
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
- Arnie Charbonneau Cancer Institute, University of Calgary, Calgary, Alberta, Canada
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12
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Micheletti C, Orland H. Efficient Sampling of Knotting-Unknotting Pathways for Semiflexible Gaussian Chains. Polymers (Basel) 2017; 9:polym9060196. [PMID: 30970873 PMCID: PMC6432015 DOI: 10.3390/polym9060196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 05/17/2017] [Accepted: 05/19/2017] [Indexed: 11/16/2022] Open
Abstract
We propose a stochastic method to generate exactly the overdamped Langevin dynamics of semi-flexible Gaussian chains, conditioned to evolve between given initial and final conformations in a preassigned time. The initial and final conformations have no restrictions, and hence can be in any knotted state. Our method allows the generation of statistically independent paths in a computationally efficient manner. We show that these conditioned paths can be exactly generated by a set of local stochastic differential equations. The method is used to analyze the transition routes between various knots in crossable filamentous structures, thus mimicking topological reconnections occurring in soft matter systems or those introduced in DNA by topoisomerase enzymes. We find that the average number of crossings, writhe and unknotting number are not necessarily monotonic in time and that more complex topologies than the initial and final ones can be visited along the route.
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Affiliation(s)
- Cristian Micheletti
- International School for Advanced Studies (SISSA), Physics Area via Bonomea 265, I-34136 Trieste, Italy.
| | - Henri Orland
- Institut de Physique Théorique, CEA, CNRS, UMR3681, F-91191 Gif-sur-Yvette, France.
- Beijing Computational Science Research Center, No.10 East Xibeiwang Road, 100193 Beijing, China.
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13
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Bates D, Pettitt BM, Buck GR, Zechiedrich L. Importance of disentanglement and entanglement during DNA replication and segregation: Comment on: "Disentangling DNA molecules" by Alexander Vologodskii. Phys Life Rev 2016; 18:160-164. [PMID: 27666770 DOI: 10.1016/j.plrev.2016.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 09/08/2016] [Indexed: 10/21/2022]
Affiliation(s)
- David Bates
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - B Montgomery Pettitt
- Sealy Center for Structural Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Gregory R Buck
- Department of Mathematics, St. Anselm College, Manchester, NH, USA
| | - Lynn Zechiedrich
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA; Department of Pharmacology, Baylor College of Medicine, Houston, TX, USA.
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14
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Yan J. Mechanisms of DNA disentangling by type II topoisomerases. Phys Life Rev 2016; 18:158-159. [DOI: 10.1016/j.plrev.2016.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 09/14/2016] [Indexed: 10/21/2022]
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15
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Model of DNA topology simplification has come full (supercoiled) circle after two decades of research. Phys Life Rev 2016; 18:154-157. [DOI: 10.1016/j.plrev.2016.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 06/15/2016] [Indexed: 11/23/2022]
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16
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Chan HS, Liu Z. Thermodynamics and kinetics of TopoII action: A consensus on T-segment curvature selection? Comment on “Disentangling DNA Molecules” by Alexander Vologodskii. Phys Life Rev 2016; 18:135-138. [DOI: 10.1016/j.plrev.2016.05.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
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17
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Topology simplification: Important biological phenomenon or evolutionary relic? Phys Life Rev 2016; 18:144-146. [DOI: 10.1016/j.plrev.2016.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 07/04/2016] [Indexed: 11/22/2022]
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18
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Grosberg AY. Vingt ans après (Twenty years after): Comment on "Disentangling DNA molecules" by Alexander Vologodskii. Phys Life Rev 2016; 18:139-143. [PMID: 27432779 DOI: 10.1016/j.plrev.2016.07.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Accepted: 07/04/2016] [Indexed: 11/17/2022]
Affiliation(s)
- Alexander Y Grosberg
- Department of Physics and Center for Soft Matter Research, New York University, 4 Washington Place, New York, NY 10003, USA.
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Rybenkov VV. When Maxwellian demon meets action at a distance: Comment on "Disentangling DNA molecules" by Alexander Vologodskii. Phys Life Rev 2016; 18:150-153. [PMID: 27372001 DOI: 10.1016/j.plrev.2016.06.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 06/22/2016] [Indexed: 11/13/2022]
Affiliation(s)
- Valentin V Rybenkov
- Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, OK 73019, USA.
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