DOCSLIB.ORG

The Consequences of Rad51 Overexpression for Normal and Tumor Cells

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Consequences of Rad51 Overexpression for Normal and Tumor Cells dna repair 7 (2008) 686–693 available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/dnarepair Mini review The consequences of Rad51 overexpression for normal and tumor cells Hannah L. Klein ∗ Department of Biochemistry, New York University School of Medicine, NYU Medical Center, 550 First Avenue, New York, NY 10016, United States article info abstract Article history: The Rad51 recombinase is an essential factor for homologous recombination and the Received 11 December 2007 repair of DNA double strand breaks, binding transiently to both single stranded and double Accepted 12 December 2007 stranded DNA during the recombination reaction. The use of a homologous recombination Published on line 1 February 2008 mechanism to repair DNA damage is controlled at several levels, including the binding of Rad51 to single stranded DNA to form the Rad51 nucleofilament, which is controlled through Keywords: the action of DNA helicases that can counteract nucleofilament formation. Overexpression Rad51 protein of Rad51 in different organisms and cell types has a wide assortment of consequences, rang- Overexpression of Rad51 ing from increased homologous recombination and increased resistance to DNA damaging Genomic instability agents to disruption of the cell cycle and apoptotic cell death. Rad51 expression is increased Tumor cell drug resistance in p53-negative cells, and since p53 is often mutated in tumor cells, there is a tendency for Homologous recombination Rad51 to be overexpressed in tumor cells, leading to increased resistance to DNA damage Gene targeting and drugs used in chemotherapies. As cells with increased Rad51 levels are more resis- tant to DNA damage, there is a selection for tumor cells to have higher Rad51 levels. While increased Rad51 can provide drug resistance, it also leads to increased genomic instability and may contribute to carcinogenesis. © 2007 Elsevier B.V. All rights reserved. Contents 1. Introduction .................................................................................................................. 687 2. Fungal systems............................................................................................................... 687 2.1. Schizosaccharomyces pombe ............................................................................................ 687 2.2. Saccharomyces cerevisiae ............................................................................................... 687 3. Drosophila .................................................................................................................... 688 4. Regulation of RAD51 expression in mammalian systems.................................................................. 688 5. Rad51 overexpression in human tumors and cell lines .................................................................... 689 6. Effects of Rad51 overexpression on recombination in mammalian cells.................................................. 690 7. Conclusions .................................................................................................................. 691 Acknowledgement ........................................................................................................... 691 References .................................................................................................................... 691 ∗ Tel.: +1 212 263 5778; fax: +1 212 263 8166. E-mail address: [email protected]. 1568-7864/$ – see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.dnarep.2007.12.008 dna repair 7 (2008) 686–693 687 proportion of cells displaying the “cut” phenotype was related 1. Introduction to the level of Rhp51 overexpression. The cell morphology sug- gested that overexpression of Rhp51 induced a DNA damage DNA double strand breaks (DSBs) occur through several checkpoint prior to mitosis. This was accompanied by a dis- sources; through the action of exogenous agents such as ioniz- ruption of microtubule attachments to the chromosomes. A ing radiation, through inhibition of DNA topoisomerases, and FACS analysis showed that a large fraction of cells had a 1C from endogenous programmed events such as V(D)J recom- DNA content, indicative of a delay in entering into S phase. bination in the immunoglobulin genes and Spo11-promoted The authors suggest that DNA replication is interfered when meiotic recombination [1]. DSBs can be repaired by end join- Rhp51 is overexpressed. As overexpression of a mutant form ing pathways that do not utilize significant homology at the of Rhp51 that is most likely defective in binding to DNA based broken ends, or through homologous recombination (HR), on an identical mutation in the Saccharomyces cerevisiae Rad51 which uses homology at the broken ends to intact sequences protein [9,10] did not inhibit cell growth, interference with in the genome to repair the breaks. When HR is used for replication and cell growth requires that the overexpressed repair, in eukaryotes it is promoted by the recombinase Rad51, Rhp51 be bound to DNA rather than causing a defect by bind- which binds to 3’-tailed single strands at the end of DSBs ing to other protein factors and depleting these from their in a helical fashion and promotes pairing with homologous normal cellular compartment and function. DNA sequences as a prelude to strand invasion and repair of the DSBs [1–4]. Since eukaryotic genomes contain dis- 2.2. Saccharomyces cerevisiae persed repeated DNA, repair of DSBs through HR can occur not only through an interaction with the sister chromatid or Several studies have reported on the effects of Rad51 overex- the homolog chromosome, but also with repeats on nonho- pression in S. cerevisiae. Since the level of overexpression varies molog chromosomes (sometimes called ectopic HR). Ectopic in these studies, in some cases Rad51 overexpression has been HR can result in genomic rearrangements and instability. It more deleterious than in other cases. Rad51 interacts with follows then that mitotic HR must be regulated to ensure that the mediator proteins Rad52, Rad55, and Rad57, which over- DSB repair is not mutagenic. come the inhibitory effect of RPA binding to ssDNA in in vitro Although the regulation of mitotic HR is not fully under- reactions for Rad51 nucleofilament formation [11–13]. Overex- stood, we are now beginning to appreciate the role that Rad51 pression of Rad51 can suppress the in vivo effects of non-null expression levels play in regulating HR, as Rad51 overexpres- rad52 mutations [14–17],orrad55 and rad57 deletion muta- sion is found in human tumors, and its increase is related to tions [18]. The assays for suppression involve DNA damage p53 function. Rad51 performs a vital function during the nor- resistance and an increase in recombination rates. In no case mal cell cycle as the RAD51 knockout in chicken and mouse was any deleterious effect of Rad51 overexpression reported, cells is lethal [5–7]. However, too much Rad51 protein also although the level of overexpression ranged from twofold to has deleterious consequences. These findings emphasize that what is estimated to be at least a 10-fold increase in protein Rad51 expression and activity must be carefully regulated. In levels. Rad51 overexpression was also able to partially rescue fungal systems where Rad51 is not essential, mutations that the meiotic defects of rad52 mutants, using spore viability as reduce or destroy Rad51 activity result in increased sensitiv- a measure of successful meioses. ity to DNA damaging agents that create DSBs, a reduction S. cerevisiae has a meiotic-specific Rad51 paralog called in spontaneous mitotic HR rates, an increase in genomic Dmc1, which acts together with Hop2 to promote meiotic rearrangements and an inability to complete meiotic recom- crossing over. dmc1 and hop2 mutants are defective in meiotic bination. Thus HR is an essential feature of a normal cell crossing over and have greatly reduced spore formation and cycle, but must be held in check to prevent unwanted rear- viability. These defects can be counteracted by overexpression rangements. Increased Rad51 expression in tumor cells also of Rad51 [19]. While excess Rad51 could complement meiotic has the unwanted effect of bestowing increased resistance to mutants and promote HR under these mutant conditions, it DNA damage, rendering the cells resistant to drug therapies. did not enhance HR in wildtype cells. Here we review the effects of Rad51 overexpression in yeasts, Rad51 is a dynamic protein that forms nucleofilaments on Drosophila, and mammalian systems. ssDNA in preparation for HR, then is bound to dsDNA after homologous strand invasion to form a D-loop, the synapsis intermediate, and finally is removed from DNA to allow com- 2. Fungal systems pletion of the HR repair reaction by gap filling strand synthesis. To insure that only appropriate DNA lesions are targeted for 2.1. Schizosaccharomyces pombe HR repair during mitotic growth, cells have devised various mechanisms to prevent inappropriate Rad51 nucleofilament The Rad51 homolog, Rhp51, has been overexpressed in wild- formation. In S. cerevisiae this is achieved through the action of type S. pombe cells and results in disruption of the cell cycle [8]. the Srs2 DNA helicase, which acts as a translocase to antago- The expression level ranged from 80-fold to 700-fold over the nize and disassemble Rad51 nucleofilaments [1]. Thus it might normal level of Rhp51, using an inducible promoter. As the be anticipated that there is a fine balance between Rad51 pro- level of
Load more

Recommended publications
  • Deficiency in the DNA Repair Protein ERCC1 Triggers a Link Between Senescence and Apoptosis in Human Fibroblasts and Mouse Skin
    Lawrence Berkeley National Laboratory Recent Work Title Deficiency in the DNA repair protein ERCC1 triggers a link between senescence and apoptosis in human fibroblasts and mouse skin. Permalink https://escholarship.org/uc/item/73j1s4d1 Journal Aging cell, 19(3) ISSN 1474-9718 Authors Kim, Dong Eun Dollé, Martijn ET Vermeij, Wilbert P et al. Publication Date 2020-03-01 DOI 10.1111/acel.13072 Peer reviewed eScholarship.org Powered by the California Digital Library University of California Received: 10 June 2019 | Revised: 7 October 2019 | Accepted: 30 October 2019 DOI: 10.1111/acel.13072 ORIGINAL ARTICLE Deficiency in the DNA repair protein ERCC1 triggers a link between senescence and apoptosis in human fibroblasts and mouse skin Dong Eun Kim1 | Martijn E. T. Dollé2 | Wilbert P. Vermeij3,4 | Akos Gyenis5 | Katharina Vogel5 | Jan H. J. Hoeijmakers3,4,5 | Christopher D. Wiley1 | Albert R. Davalos1 | Paul Hasty6 | Pierre-Yves Desprez1 | Judith Campisi1,7 1Buck Institute for Research on Aging, Novato, CA, USA Abstract 2Centre for Health Protection Research, ERCC1 (excision repair cross complementing-group 1) is a mammalian endonuclease National Institute of Public Health and that incises the damaged strand of DNA during nucleotide excision repair and inter- the Environment (RIVM), Bilthoven, The −/Δ Netherlands strand cross-link repair. Ercc1 mice, carrying one null and one hypomorphic Ercc1 3Department of Molecular Genetics, allele, have been widely used to study aging due to accelerated aging phenotypes Erasmus University Medical Center, −/Δ Rotterdam, The Netherlands in numerous organs and their shortened lifespan. Ercc1 mice display combined 4Princess Máxima Center for Pediatric features of human progeroid and cancer-prone syndromes.
    [Show full text]
  • Evolutionary Origins of DNA Repair Pathways: Role of Oxygen Catastrophe in the Emergence of DNA Glycosylases
    cells Review Evolutionary Origins of DNA Repair Pathways: Role of Oxygen Catastrophe in the Emergence of DNA Glycosylases Paulina Prorok 1 , Inga R. Grin 2,3, Bakhyt T. Matkarimov 4, Alexander A. Ishchenko 5 , Jacques Laval 5, Dmitry O. Zharkov 2,3,* and Murat Saparbaev 5,* 1 Department of Biology, Technical University of Darmstadt, 64287 Darmstadt, Germany; [email protected] 2 SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; [email protected] 3 Center for Advanced Biomedical Research, Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia 4 National Laboratory Astana, Nazarbayev University, Nur-Sultan 010000, Kazakhstan; [email protected] 5 Groupe «Mechanisms of DNA Repair and Carcinogenesis», Equipe Labellisée LIGUE 2016, CNRS UMR9019, Université Paris-Saclay, Gustave Roussy Cancer Campus, F-94805 Villejuif, France; [email protected] (A.A.I.); [email protected] (J.L.) * Correspondence: [email protected] (D.O.Z.); [email protected] (M.S.); Tel.: +7-(383)-3635187 (D.O.Z.); +33-(1)-42115404 (M.S.) Abstract: It was proposed that the last universal common ancestor (LUCA) evolved under high temperatures in an oxygen-free environment, similar to those found in deep-sea vents and on volcanic slopes. Therefore, spontaneous DNA decay, such as base loss and cytosine deamination, was the Citation: Prorok, P.; Grin, I.R.; major factor affecting LUCA’s genome integrity. Cosmic radiation due to Earth’s weak magnetic field Matkarimov, B.T.; Ishchenko, A.A.; and alkylating metabolic radicals added to these threats.
    [Show full text]
  • Paul Modrich Howard Hughes Medical Institute and Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
    Mechanisms in E. coli and Human Mismatch Repair Nobel Lecture, December 8, 2015 by Paul Modrich Howard Hughes Medical Institute and Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA. he idea that mismatched base pairs occur in cells and that such lesions trig- T ger their own repair was suggested 50 years ago by Robin Holliday in the context of genetic recombination [1]. Breakage and rejoining of DNA helices was known to occur during this process [2], with precision of rejoining attributed to formation of a heteroduplex joint, a region of helix where the two strands are derived from the diferent recombining partners. Holliday pointed out that if this heteroduplex region should span a genetic diference between the two DNAs, then it will contain one or more mismatched base pairs. He invoked processing of such mismatches to explain the recombination-associated phenomenon of gene conversion [1], noting that “If there are enzymes which can repair points of damage in DNA, it would seem possible that the same enzymes could recognize the abnormality of base pairing, and by exchange reactions rectify this.” Direct evidence that mismatches provoke a repair reaction was provided by bacterial transformation experiments [3–5], and our interest in this efect was prompted by the Escherichia coli (E. coli) work done in Matt Meselson’s lab at Harvard. Using artifcially constructed heteroduplex DNAs containing multiple mismatched base pairs, Wagner and Meselson [6] demonstrated that mismatches elicit a repair reaction upon introduction into the E. coli cell. Tey also showed that closely spaced mismatches, mismatches separated by a 1000 base pairs or so, are usually repaired on the same DNA strand.
    [Show full text]
  • Predictive Value of RAD51 on the Survival and Drug Responsiveness of Ovarian Cancer Yuchen Feng1, Daoqi Wang2, Luyang Xiong3, Guohua Zhen1 and Jiahong Tan4*
    Feng et al. Cancer Cell Int (2021) 21:249 https://doi.org/10.1186/s12935-021-01953-5 Cancer Cell International PRIMARY RESEARCH Open Access Predictive value of RAD51 on the survival and drug responsiveness of ovarian cancer Yuchen Feng1, Daoqi Wang2, Luyang Xiong3, Guohua Zhen1 and Jiahong Tan4* Abstract Background: Ovarian cancer has greatly endangered and deteriorated female health conditions worldwide. Refne- ment of predictive biomarkers could enable patient stratifcation and help optimize disease management. Methods: RAD51 expression profle, target-disease associations, and ftness scores of RAD51 were analyzed in ovar- ian cancer using bioinformatic analysis. To further identify its role, gene enrichment analysis was performed, and a regulatory network was constructed. Survival analysis and drug sensitivity assay were performed to evaluate the efect of RAD51 expression on ovarian cancer prognosis. The predictive value of RAD51 was then confrmed in a validation cohort immunohistochemically. Results: Ovarian cancer expressed more RAD51 than normal ovary. RAD51 conferred ovarian cancer dependency and was associated with ovarian cancer. RAD51 had extensive target-disease associations with various diseases, including ovarian cancer. Genes that correlate with and interact with RAD51 were involved in DNA damage repair and drug responsiveness. High RAD51 expression indicated unfavorable survival outcomes and resistance to platinum, taxane, and PARP inhibitors in ovarian cancer. In the validation cohort (126 patients), high RAD51 expression indicated platinum resistance, and platinum-resistant patients expressed more RAD51. Patients with high RAD51 expression had shorter OS (HR 2.968, P < 0.0001) and poorer PFS (HR 2.838, P < 0.0001). RAD51 expression level was negatively cor- related with patients’= survival length.
    [Show full text]
  • The Bloom Syndrome Protein Limits the Lethality Associated with RAD51 Deficiency
    Published OnlineFirst March 9, 2010; DOI: 10.1158/1541-7786.MCR-09-0534 Molecular DNA Damage and Cellular Stress Responses Cancer Research The Bloom Syndrome Protein Limits the Lethality Associated with RAD51 Deficiency Kenza Lahkim Bennani-Belhaj1,2, Sébastien Rouzeau1,2, Géraldine Buhagiar-Labarchède1,2, Pauline Chabosseau1,2, Rosine Onclercq-Delic1,2, Emilie Bayart1, Fabrice Cordelières3,4, Jérôme Couturier5,6, and Mounira Amor-Guéret1,2 Abstract Little is known about the functional interaction between the Bloom's syndrome protein (BLM) and the re- combinase RAD51 within cells. Using RNA interference technology, we provide the first demonstration that RAD51 acts upstream from BLM to prevent anaphase bridge formation. RAD51 downregulation was associated with an increase in the frequency of BLM-positive anaphase bridges, but not of BLM-associated ultrafine bridges. Time-lapse live microscopy analysis of anaphase bridge cells revealed that BLM promoted cell survival in the absence of Rad51. Our results directly implicate BLM in limiting the lethality associated with RAD51 deficiency through the processing of anaphase bridges resulting from the RAD51 defect. These findings provide insight into the molecular basis of some cancers possibly associated with variants of the RAD51 gene family. Mol Cancer Res; 8(3); 385–94. ©2010 AACR. Introduction cently, SUMOylation of BLM has been shown to regulate its association with RAD51 and its function in HR-medi- Bloom's syndrome displays one of the strongest known ated repair of damaged replication forks (13). In several correlations between chromosomal instability and a high models, it has been proposed that BLM restarts replication risk of cancer at an early age.
    [Show full text]
  • Mutations in the RAD54 Recombination Gene in Primary Cancers
    Oncogene (1999) 18, 3427 ± 3430 ã 1999 Stockton Press All rights reserved 0950 ± 9232/99 $12.00 http://www.stockton-press.co.uk/onc SHORT REPORT Mutations in the RAD54 recombination gene in primary cancers Masahiro Matsuda1,4, Kiyoshi Miyagawa*,1,2, Mamoru Takahashi2,4, Toshikatsu Fukuda1,4, Tsuyoshi Kataoka4, Toshimasa Asahara4, Hiroki Inui5, Masahiro Watatani5, Masayuki Yasutomi5, Nanao Kamada3, Kiyohiko Dohi4 and Kenji Kamiya2 1Department of Molecular Pathology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Hiroshima 734, Japan; 2Department of Developmental Biology and Oncology, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Hiroshima 734, Japan; 3Department of Cancer Cytogenetics, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-2-3 Kasumi, Hiroshima 734, Japan; 42nd Department of Surgery, Hiroshima University School of Medicine, 1-2-3 Kasumi, Minami-ku, Hiroshima 734, Japan; 51st Department of Surgery, Kinki University School of Medicine, 377-2 Ohno-higashi, Osaka-sayama, Osaka 589, Japan Association of a recombinational repair protein RAD51 therefore, probable that members of the RAD52 with tumor suppressors BRCA1 and BRCA2 suggests epistasis group are altered in cancer. that defects in homologous recombination are responsible To investigate whether RAD54, a member of the for tumor formation. Also recent ®ndings that a protein RAD52 epistasis group, is mutated in human cancer, associated with the MRE11/RAD50 repair complex is we performed SSCP analysis and direct sequencing of mutated in Nijmegen breakage syndrome characterized PCR products using mRNAs from 132 unselected by increased cancer incidence and ionizing radiation primary tumors including 95 breast cancers, 13 sensitivity strongly support this idea.
    [Show full text]
  • DNA Repair with Its Consequences (E.G
    Cell Science at a Glance 515 DNA repair with its consequences (e.g. tolerance and pathways each require a number of apoptosis) as well as direct correction of proteins. By contrast, O-alkylated bases, Oliver Fleck* and Olaf Nielsen* the damage by DNA repair mechanisms, such as O6-methylguanine can be Department of Genetics, Institute of Molecular which may require activation of repaired by the action of a single protein, Biology, University of Copenhagen, Øster checkpoint pathways. There are various O6-methylguanine-DNA Farimagsgade 2A, DK-1353 Copenhagen K, Denmark forms of DNA damage, such as base methyltransferase (MGMT). MGMT *Authors for correspondence (e-mail: modifications, strand breaks, crosslinks removes the alkyl group in a suicide fl[email protected]; [email protected]) and mismatches. There are also reaction by transfer to one of its cysteine numerous DNA repair pathways. Each residues. Photolyases are able to split Journal of Cell Science 117, 515-517 repair pathway is directed to specific Published by The Company of Biologists 2004 covalent bonds of pyrimidine dimers doi:10.1242/jcs.00952 types of damage, and a given type of produced by UV radiation. They bind to damage can be targeted by several a UV lesion in a light-independent Organisms are permanently exposed to pathways. Major DNA repair pathways process, but require light (350-450 nm) endogenous and exogenous agents that are mismatch repair (MMR), nucleotide as an energy source for repair. Another damage DNA. If not repaired, such excision repair (NER), base excision NER-independent pathway that can damage can result in mutations, diseases repair (BER), homologous recombi- remove UV-induced damage, UVER, is and cell death.
    [Show full text]
  • DNA Proofreading and Repair
    DNA proofreading and repair Mechanisms to correct errors during DNA replication and to repair DNA damage over the cell's lifetime. Key points: Cells have a variety of mechanisms to prevent mutations, or permanent changes in DNA sequence. During DNA synthesis, most DNA polymerases "check their work," fixing the majority of mispaired bases in a process called proofreading. Immediately after DNA synthesis, any remaining mispaired bases can be detected and replaced in a process called mismatch repair. If DNA gets damaged, it can be repaired by various mechanisms, including chemical reversal, excision repair, and double-stranded break repair. Introduction What does DNA have to do with cancer? Cancer occurs when cells divide in an uncontrolled way, ignoring normal "stop" signals and producing a tumor. This bad behavior is caused by accumulated mutations, or permanent sequence changes in the cells' DNA. Replication errors and DNA damage are actually happening in the cells of our bodies all the time. In most cases, however, they don’t cause cancer, or even mutations. That’s because they are usually detected and fixed by DNA proofreading and repair mechanisms. Or, if the damage cannot be fixed, the cell will undergo programmed cell death (apoptosis) to avoid passing on the faulty DNA. Mutations happen, and get passed on to daughter cells, only when these mechanisms fail. Cancer, in turn, develops only when multiple mutations in division-related genes accumulate in the same cell. In this article, we’ll take a closer look at the mechanisms used by cells to correct replication errors and fix DNA damage, including: Proofreading, which corrects errors during DNA replication Mismatch repair, which fixes mispaired bases right after DNA replication DNA damage repair pathways, which detect and correct damage throughout the cell cycle Proofreading DNA polymerases are the enzymes that build DNA in cells.
    [Show full text]
  • Scaffolding Protein SPIDR/KIAA0146 Connects the Bloom Syndrome Helicase with Homologous Recombination Repair
    Scaffolding protein SPIDR/KIAA0146 connects the Bloom syndrome helicase with homologous recombination repair Li Wan1, Jinhua Han1, Ting Liu1, Shunli Dong, Feng Xie, Hongxia Chen, and Jun Huang2 Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China Edited by James E. Cleaver, University of California, San Francisco, CA, and approved February 26, 2013 (received for review December 1, 2012) The Bloom syndrome gene product, BLM, is a member of the highly of the SDSA pathway (6, 7). The ability of BLM to yield non- conserved RecQ family. An emerging concept is the BLM helicase crossover products is thought to play a critical role in the avoidance collaborates with the homologous recombination (HR) machinery to of chromosomal rearrangements during the homolog-directed re- help avoid undesirable HR events and to achieve a high degree of pair of chromosomal lesions. As a result, cells defective for BLM fidelity during the HR reaction. However, exactly how such coordina- exhibit elevated rates of sister chromatid exchange (SCE) (19–21). tion occurs in vivo is poorly understood. Here, we identified a protein Upon the occurrence of DNA damage, BLM is able to form termed SPIDR (scaffolding protein involved in DNA repair) as the link discrete foci, where it colocalizes with other DNA repair proteins between BLM and the HR machinery. SPIDR independently interacts (22, 23). However, mechanistically how BLM is recruited to sites with BLM and RAD51 and promotes the formation of a BLM/RAD51- of DNA damage and how it collaborates with other proteins to containing complex of biological importance. Consistent with its role mediate recombination repair remain largely unexplored.
    [Show full text]
  • Error-Prone DNA Repair As Cancer's Achilles' Heel
    cancers Review Alternative Non-Homologous End-Joining: Error-Prone DNA Repair as Cancer’s Achilles’ Heel Daniele Caracciolo, Caterina Riillo , Maria Teresa Di Martino , Pierosandro Tagliaferri and Pierfrancesco Tassone * Department of Experimental and Clinical Medicine, Magna Græcia University, Campus Salvatore Venuta, 88100 Catanzaro, Italy; [email protected] (D.C.); [email protected] (C.R.); [email protected] (M.T.D.M.); [email protected] (P.T.) * Correspondence: [email protected] Simple Summary: Cancer onset and progression lead to a high rate of DNA damage, due to replicative and metabolic stress. To survive in this dangerous condition, cancer cells switch the DNA repair machinery from faithful systems to error-prone pathways, strongly increasing the mutational rate that, in turn, supports the disease progression and drug resistance. Although DNA repair de-regulation boosts genomic instability, it represents, at the same time, a critical cancer vulnerability that can be exploited for synthetic lethality-based therapeutic intervention. We here discuss the role of the error-prone DNA repair, named Alternative Non-Homologous End Joining (Alt-NHEJ), as inducer of genomic instability and as a potential therapeutic target. We portray different strategies to drug Alt-NHEJ and discuss future challenges for selecting patients who could benefit from Alt-NHEJ inhibition, with the aim of precision oncology. Abstract: Error-prone DNA repair pathways promote genomic instability which leads to the onset of cancer hallmarks by progressive genetic aberrations in tumor cells. The molecular mechanisms which Citation: Caracciolo, D.; Riillo, C.; Di foster this process remain mostly undefined, and breakthrough advancements are eagerly awaited. Martino, M.T.; Tagliaferri, P.; Tassone, In this context, the alternative non-homologous end joining (Alt-NHEJ) pathway is considered P.
    [Show full text]
  • DNA Damage and Repair
    What is DNA? DNA/RNA: polynucleotide chains Phosphate Base Sugar (2’ OH=ribose, 2’H=deoxyribose) Nucleotide =sugar+phosphate+base DNA is a double helix DNA damage and repair • How is DNA damaged? • How is DNA repaired? • How does the type of damage impact repair? • Accumulated DNA damage=death (by cancer, or old age) • “No one here gets out alive” –Jim Morrison Adduct formation • Nasty chemicals(carcinogens) that adduct to DNA; often to ring Nitrogens in bases – E.g. Alkylating agents: reactive carbon containing chemicals (ethylating agents, methylating agents) Adduct formation • Not always direct exposure: sometimes carcinogen is toxic product of cellular metabolism – Cigarette smoke; benzo-a- pyrene not a big deal…but the break down product is • Groups are bulky, blocks transcription, replication; can interfere with base pairing, and introduce mutation during replication Radiation: UV light • Non-ionizing radiation (UV light from the sun) – Bases absorb energy with peak at 260nM..this is UV – Photoactivates base, causes nasty chemistry – Result is…covalent bonds between adajacent bases, almost always adjacent pyrimidines – Distorts DNA (kink), can block transcription, replication, lead to mutation T T T C Spontaneous Damage: Base loss • Some times bases just fall off (more often than you might think; 10000/genome/generation) • Bases gone, but phosphodiester backbone is still intact • Purines more sensitive than pyrimidines (acid sensitive) • Causes mutation, can lead to strand breaks Spontaneous damage: deamination 1. Converts C to U etc… 2. Altered base has different base pairing rule – e.g. U pairs with A (converts CG bp to UA) 3. Unless repaired results in transition mutation Oxidative stress • Reactive oxygen species (ROS); things that are or give rise to oxygen with an unpaired electron; a free radical • E.g hydroxyl radical H O • ROS produced by….
    [Show full text]
  • Recruitment of Mismatch Repair Proteins to the Site of DNA Damage in Human Cells
    3146 Research Article Recruitment of mismatch repair proteins to the site of DNA damage in human cells Zehui Hong, Jie Jiang, Kazunari Hashiguchi, Mikiko Hoshi, Li Lan and Akira Yasui* Department of Molecular Genetics, Institute of Development, Aging and Cancer, Tohoku University, Seiryomachi 4-1, Aobaku, Sendai 980-8575, Japan *Author for correspondence (e-mail: [email protected]) Accepted 8 July 2008 Journal of Cell Science 121, 3146-3154 Published by The Company of Biologists 2008 doi:10.1242/jcs.026393 Summary Mismatch repair (MMR) proteins contribute to genome stability the PCNA-binding domain of MSH6. MSH2 is recruited to the by excising DNA mismatches introduced by DNA polymerase. DNA damage site through interactions with either MSH3 or Although MMR proteins are also known to influence cellular MSH6, and is required for recruitment of MLH1 to the damage responses to DNA damage, how MMR proteins respond to DNA site. We found, furthermore, that MutSβ is also recruited to damage within the cell remains unknown. Here, we show that UV-irradiated sites in nucleotide-excision-repair- and PCNA- MMR proteins are recruited immediately to the sites of various dependent manners. Thus, MMR and its proteins function not types of DNA damage in human cells. MMR proteins are only in replication but also in DNA repair. recruited to single-strand breaks in a poly(ADP-ribose)- dependent manner as well as to double-strand breaks. Using Supplementary material available online at mutant cells, RNA interference and expression of fluorescence- http://jcs.biologists.org/cgi/content/full/121/19/3146/DC1
    [Show full text]