scholarly journals Supraphysiological protection from replication stress does not extend mammalian lifespan

2020 ◽  
Author(s):  
Eliene Albers ◽  
Alexandra Avram ◽  
Mauro Sbroggio ◽  
Oscar Fernandez-Capetillo ◽  
Andres J Lopez-Contreras
Keyword(s):  
Dna Damage ◽  
Transgenic Mice ◽  
Genomic Instability ◽  
Genetic Background ◽  
Replication Fork ◽  
Accelerated Aging ◽  
Replication Stress ◽  
Term Survival ◽  
Survival Studies

AbstractReplication Stress (RS) is a type of DNA damage generated at the replication fork, characterized by single-stranded DNA (ssDNA) accumulation, and which can be caused by a variety of factors. Previous studies have reported elevated RS levels in aged cells. In addition, mouse models with a deficient RS response show accelerated aging. However, the relevance of endogenous or physiological RS, compared to other sources of genomic instability, for the normal onset of aging is unknown. We have performed long term survival studies of transgenic mice with extra copies of the Chk1 and/or Rrm2 genes, which we previously showed extend the lifespan of a progeroid ATR-hypomorphic model suffering from high levels of RS. In contrast to their effect in the context of progeria, the lifespan of Chk1, Rrm2 and Chk1/Rrm2 transgenic mice was similar to WT littermates in physiological settings. Most mice studied died due to tumors -mainly lymphomas-irrespective of their genetic background. Interestingly, a slightly higher percentage of transgenic mice developed tumors compared to WT mice. Our results indicate that supraphysiological protection from RS does not extend lifespan, indicating that RS may not be a relevant source of genomic instability on the onset of “normal” aging.

scholarly journals SLX4–XPF mediates DNA damage responses to replication stress induced by DNA–protein interactions

2020 ◽  
Vol 220 (1) ◽  
Author(s):  
Riko Ishimoto ◽  
Yota Tsuzuki ◽  
Tomoki Matsumura ◽  
Seiichiro Kurashige ◽  
Kouki Enokitani ◽  
...  
Keyword(s):  
Dna Damage ◽  
Protein Interactions ◽  
Chromosomal Instability ◽  
Replication Fork ◽  
Protein Complexes ◽  
Critical Role ◽  
Replication Stress ◽  
S Phase ◽  
Damage Response

The DNA damage response (DDR) has a critical role in the maintenance of genomic integrity during chromosome replication. However, responses to replication stress evoked by tight DNA–protein complexes have not been fully elucidated. Here, we used bacterial LacI protein binding to lacO arrays to make site-specific replication fork barriers on the human chromosome. These barriers induced the accumulation of single-stranded DNA (ssDNA) and various DDR proteins at the lacO site. SLX4–XPF functioned as an upstream factor for the accumulation of DDR proteins, and consequently, ATR and FANCD2 were interdependently recruited. Moreover, LacI binding in S phase caused underreplication and abnormal mitotic segregation of the lacO arrays. Finally, we show that the SLX4–ATR axis represses the anaphase abnormality induced by LacI binding. Our results outline a long-term process by which human cells manage nucleoprotein obstacles ahead of the replication fork to prevent chromosomal instability.

Experimental Simplification of the Excimer Laser-Assisted Nonocclusive Anastomosis (ELANA) Technique

2010 ◽  
Vol 67 (3) ◽  
pp. ons-ons ◽  
Author(s):  
Tristan P.C. van Doormaal ◽  
Albert van der Zwan ◽  
Bon H. Verweij ◽  
Matthijs Biesbroek ◽  
Luca Regli ◽  
...  
Keyword(s):  
Excimer Laser ◽  
Potential Benefit ◽  
Burst Pressure ◽  
Application Time ◽  
Term Survival ◽  
New Techniques ◽  
Recipient Artery ◽  
Saphenous Veins ◽  
Survival Studies

Abstract BACKGROUND: The excimer laser-assisted nonocclusive anastomosis (ELANA) technique facilitates the construction of an end-to-side anastomosis between a donor vessel and a recipient artery without the need to temporarily occlude the recipient artery. OBJECTIVE: To test whether the surgically difficult ELANA technique can be simplified. METHODS: In 42 rabbits, with the aorta as the recipient artery and human saphenous veins as donor grafts, we made 30 conventional ELANAs with 8 microsutures, 90 ELANAs with 4 microsutures (ELANA-4s), 40 ELANAs with 2 microsutures (ELANA-2s), and 90 sutureless ELANAs (SELANAs). SELANA involved a new ring design with 2 pins. ELANA-4, ELANA-2, and SELANA were each combined with 3 different sealants (Bioglue , Tachoseal, and Tisseel ) and compared regarding application time, complications, and burst pressure. RESULTS: The conventional ELANA was constructed in a mean of 14.8 ± 2.6 minutes. All experimental anastomoses were constructed significantly faster; the ELANA-4 in a mean of 10.9 ± 1.3 minutes, the ELANA-2 in a mean of 5.4 ± 1.7 minutes, and the SELANA in a mean of 2.5 ± 1.8 minutes. All ELANA and ELANA-4 anastomoses were sufficiently strong with a burst pressure > 200 mm Hg, except for 1 insufficiently sealed ELANA-4 anastomosis. ELANA-2 was sufficiently strong only with Bioglue, showing a burst pressure < 280 mm Hg. SELANA was sufficiently strong with Bioglue or TachoSil, showing a burst pressure < 260 mm Hg. CONCLUSION: The ELANA technique can be simplified by reducing or even abandoning microsutures. Of the experimental anastomoses tested, we consider the SELANA technique combined with TachoSil of most potential benefit. Long-term survival studies will be performed in animals before we consider using any of these new techniques in patients.

scholarly journals Nutritional Preconditioning in Cancer Treatment in Relation to DNA Damage and Aging

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Winnie M.C. van den Boogaard ◽  
Marry M. van den Heuvel-Eibrink ◽  
Jan H.J. Hoeijmakers ◽  
Wilbert P. Vermeij
Keyword(s):  
Dna Damage ◽  
Cancer Treatment ◽  
Cancer Biology ◽  
Accelerated Aging ◽  
Nutritional Intervention ◽  
Annual Review ◽  
Publication Date ◽  
Short And Long Term ◽  
Resilience Mechanisms

Dietary restriction (DR) is the most successful nutritional intervention for extending life span and preserving health in numerous species. Reducing food intake triggers a protective response that shifts energy resources from growth to maintenance and resilience mechanisms. This so-called survival response has been shown to particularly increase life and health span and decrease DNA damage in DNA repair–deficient mice exhibiting accelerated aging. Accumulation of DNA damage is the main cause of aging, but also of cancer. Moreover, radiotherapies and most chemotherapies are based on damaging DNA, consistent with their ability to induce toxicity and accelerate aging. Since fasting and DR decrease DNA damage and its effects, nutritional preconditioning holds promise for improving (cancer) therapy and preventing short- and long-term side effects of anticancer treatments. This review provides an overview of the link between aging and cancer, highlights important preclinical studies applying such nutritional preconditioning, and summarizes the first clinical trials implementing nutritional preconditioning in cancer treatment. Expected final online publication date for the Annual Review of Cancer Biology, Volume 5 is March 4, 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Abstract 3031: Replication stress and DNA damage promote genomic instability in near-tetraploid colorectal cancer cells

2015 ◽  
Author(s):  
Isabel Quintanilla ◽  
Darawalee Wangsa ◽  
Markus Brown ◽  
Amaia Ercilla ◽  
Greg Klus ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Dna Damage ◽  
Cancer Cells ◽  
Genomic Instability ◽  
Replication Stress ◽  
Colorectal Cancer Cells

Oxidative DNA damage corresponds to the long term survival of human cells treated with silver nanoparticles

2013 ◽  
Vol 219 (2) ◽  
pp. 151-159 ◽  
Author(s):  
Marcin Kruszewski ◽  
Iwona Grądzka ◽  
Teresa Bartłomiejczyk ◽  
Jadwiga Chwastowska ◽  
Sylwester Sommer ◽  
...  
Keyword(s):  
Dna Damage ◽  
Silver Nanoparticles ◽  
Oxidative Dna Damage ◽  
Human Cells ◽  
Term Survival ◽  
Long Term Survival

scholarly journals P4-370: Long-term survival of human CNS stem cells and their progeny in immunodeficient, plaque-producing APP transgenic mice

2006 ◽  
Vol 2 ◽  
pp. S626-S627
Author(s):  
George A. Carlson ◽  
Calanthe Wilson ◽  
Rebecca Young ◽  
Sherry Turner ◽  
David Westaway ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transgenic Mice ◽  
Term Survival ◽  
Long Term Survival

scholarly journals CLL Progression Is Associated with Increased Clonal Diversity and Replication Stress

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 1977-1977
Author(s):  
Angelo Agathanggelou ◽  
Anna Skowronska ◽  
Nick Davies ◽  
Marwan Kwok ◽  
Samuel Clockie ◽  
...  
Keyword(s):  
Dna Damage ◽  
Disease Progression ◽  
Genomic Instability ◽  
Conflicts Of Interest ◽  
Clonal Diversity ◽  
Replication Stress ◽  
Tp53 Gene ◽  
Genetic Alterations ◽  
Paired Samples ◽  
G1 Cells

Abstract There is increasing evidence to suggest that genetic lesions accumulate during CLL progression, often involving mutations in DNA damage response genes ATM and TP53, or SF3B1. However, little is known about the mechanisms which contribute towards genomic instability and clonal diversification during CLL progression. Genomic instability is a major cause of subclonal diversification and can be driven by replication stress (RS). It has been shown that in solid tumours RS drives tumourigenesis through the following steps: presence of unreplicated DNA, accumulation of DNA damage, activation and functional loss of ATM/p53 and genomic instability. In this study we addressed whether high proliferation rates during CLL progression are associated with increased subclonal diversification and with RS. We compared samples from the indolent and progressive stages of CLL, both in individual patients and in patient cohorts. We determined clonal diversification by two complementary methods: multiplexed-FISH and next generation sequencing (NGS). We measured RS by an assay that recognizes a region of unreplicated DNA. Using multiplexed-FISH that identifies the location of multiple genetic alterations at the single cell level, we identified in 3/11 relapsed samples the occurrence of novel subclones with ATM (11q) or TP53 (17p) deletions that were not observed in the pre-treatment tumours. These findings were corroborated by targeted NGS of recurrently mutated genes in CLL which revealed novel subclones carrying ATM, TP53, NOTCH1, SF3B1 or BIRC3 mutations at the time of relapse in 9 out of 22 paired samples. Of particular interest was the acquisition of multiple mutations in the TP53 gene observed in four patients. These data demonstrate an intrinsic propensity for clonal diversification during CLL progression. Having demonstrated an association between disease progression and subclonal diversification in CLL, we next sought to identify a mechanism behind this phenomenon. RS results in under-replicated DNA which is sequestered into nuclear compartments marked by 53BP1 protein. Therefore, the appearance of 53BP1 bodies in G1-cells represents a marker of RS. We observed that 53BP1 bodies were not present in PBMCs from healthy individuals, and that 20 CLL samples from an indolent stage of disease contained a low level of this RS marker. This was in stark contrast to the elevated proportion of CLL cells with 53BP1 bodies observed in 13 progressive tumours (p<0.0001). Finally to confirm that replication stress increases during disease progression we analysed a cohort of individual patients at different stages during the evolution of their disease. Intriguingly, and consistent with our hypothesis, we found that the proportion of 53BP1 body positive cells was stable during the indolent phase of disease and only increased significantly when the tumour made the transition from indolent to the progressive stage (p=0.0009). Collectively, our data indicate that replication stress correlates with the stage of CLL progression and may provide a mechanism behind the observed subclonal diversification. Disclosures No relevant conflicts of interest to declare.

scholarly journals Lamin A/C Depletion Enhances DNA Damage-Induced Stalled Replication Fork Arrest

2013 ◽  
Vol 33 (6) ◽  
pp. 1210-1222 ◽  
Author(s):  
Mayank Singh ◽  
Clayton R. Hunt ◽  
Raj K. Pandita ◽  
Rakesh Kumar ◽  
Chin-Rang Yang ◽  
...  
Keyword(s):  
Dna Damage ◽  
Replication Fork ◽  
Dna Damage Repair ◽  
Genomic Stability ◽  
Replication Stress ◽  
Lamin A ◽  
Replicative Stress ◽  
Damage Repair ◽  
Repair Factor ◽  
Recombination Pathway

The humanLMNAgene encodes the essential nuclear envelope proteins lamin A and C (lamin A/C). Mutations inLMNAresult in altered nuclear morphology, but how this impacts the mechanisms that maintain genomic stability is unclear. Here, we report that lamin A/C-deficient cells have a normal response to ionizing radiation but are sensitive to agents that cause interstrand cross-links (ICLs) or replication stress. In response to treatment with ICL agents (cisplatin, camptothecin, and mitomycin), lamin A/C-deficient cells displayed normal γ-H2AX focus formation but a higher frequency of cells with delayed γ-H2AX removal, decreased recruitment of the FANCD2 repair factor, and a higher frequency of chromosome aberrations. Similarly, following hydroxyurea-induced replication stress, lamin A/C-deficient cells had an increased frequency of cells with delayed disappearance of γ-H2AX foci and defective repair factor recruitment (Mre11, CtIP, Rad51, RPA, and FANCD2). Replicative stress also resulted in a higher frequency of chromosomal aberrations as well as defective replication restart. Taken together, the data can be interpreted to suggest that lamin A/C has a role in the restart of stalled replication forks, a prerequisite for initiation of DNA damage repair by the homologous recombination pathway, which is intact in lamin A/C-deficient cells. We propose that lamin A/C is required for maintaining genomic stability following replication fork stalling, induced by either ICL damage or replicative stress, in order to facilitate fork regression prior to DNA damage repair.

scholarly journals Impact of Replication Stress in Human Papillomavirus Pathogenesis

2018 ◽  
Vol 93 (2) ◽  
Author(s):  
Cary A. Moody
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Human Papillomavirus ◽  
Genomic Instability ◽  
Viral Persistence ◽  
Replication Stress ◽  
Cell Cycle Checkpoints ◽  
Premalignant Lesions ◽  
Associated Lesions ◽  
Novel Approach

ABSTRACTThe inactivation of critical cell cycle checkpoints by the human papillomavirus (HPV) oncoprotein E7 results in replication stress (RS) that leads to genomic instability in premalignant lesions. Intriguingly, RS tolerance is achieved through several mechanisms, enabling HPV to exploit the cellular RS response for viral replication and to facilitate viral persistence in the presence of DNA damage. As such, inhibitors of the RS response pathway may provide a novel approach to target HPV-associated lesions and cancers.

scholarly journals BRCA1-regulated RRM2 expression protects glioblastoma cells from endogenous replication stress and promotes tumorigenicity

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Rikke D. Rasmussen ◽  
Madhavsai K. Gajjar ◽  
Lucie Tuckova ◽  
Kamilla E. Jensen ◽  
Apolinar Maya-Mendoza ◽  
...  
Keyword(s):  
Dna Damage ◽  
Genomic Instability ◽  
Ribonucleotide Reductase ◽  
Tumour Growth ◽  
Replication Stress ◽  
Protective Role ◽  
Parp Inhibition ◽  
Protective Response ◽  
Cancer Types

AbstractOncogene-evoked replication stress (RS) fuels genomic instability in diverse cancer types. Here we report that BRCA1, traditionally regarded a tumour suppressor, plays an unexpected tumour-promoting role in glioblastoma (GBM), safeguarding a protective response to supraphysiological RS levels. Higher BRCA1 positivity is associated with shorter survival of glioma patients and the abrogation of BRCA1 function in GBM enhances RS, DNA damage (DD) accumulation and impairs tumour growth. Mechanistically, we identify a novel role of BRCA1 as a transcriptional co-activator ofRRM2(catalytic subunit of ribonucleotide reductase), whereby BRCA1-mediated RRM2 expression protects GBM cells from endogenous RS, DD and apoptosis. Notably, we show that treatment with a RRM2 inhibitor triapine reproduces the BRCA1-depletion GBM-repressive phenotypes and sensitizes GBM cells to PARP inhibition. We propose that GBM cells are addicted to the RS-protective role of the BRCA1-RRM2 axis, targeting of which may represent a novel paradigm for therapeutic intervention in GBM.

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