scholarly journals WRN helicase expression in Werner syndrome cell lines

2000 ◽  
Vol 28 (2) ◽  
pp. 648-654 ◽  
Author(s):  
M. J. Moser
Keyword(s):  
Cell Lines ◽  
Werner Syndrome ◽  
Wrn Helicase

scholarly journals Werner syndrome helicase is a selective vulnerability of microsatellite instability-high tumor cells

2019 ◽  
Author(s):  
Simone Lieb ◽  
Silvia Blaha-Ostermann ◽  
Elisabeth Kamper ◽  
Katharina Ehrenhöfer-Wölfer ◽  
Andreas Schlattl ◽  
...  
Keyword(s):  
Microsatellite Instability ◽  
Tumor Cells ◽  
Cell Lines ◽  
Cancer Cell ◽  
Large Scale ◽  
Werner Syndrome ◽  
Cancer Cell Lines ◽  
Selective Vulnerability ◽  
Functional Screening ◽  
Wrn Helicase

AbstractTargeted cancer therapy is based on exploiting selective dependencies of tumor cells. By leveraging recent large-scale genomic profiling and functional screening of cancer cell lines we identified Werner syndrome helicase (WRN) as a novel specific vulnerability of microsatellite instability-high (MSI-H) cancer cells. MSI, caused by defective mismatch repair is frequently detected in human malignancies, in particular in colorectal, endometrial and gastric cancers. We demonstrate that WRN inactivation selectively impairs the viability of MSI-H but not microsatellite stable (MSS) colorectal and endometrial cancer cell lines. In MSI-H cells, WRN loss results in the emergence of chromosome breaks, chromatin bridges and micronuclei highlighting defective genome integrity. WRN variants harboring mutations abrogating the ATPase function of WRN helicase fail to rescue the viability phenotype of WRN-depleted MSI-H colorectal cells. Our study suggests that pharmacological inhibition of WRN helicase function might represent a novel opportunity to develop a targeted therapy for MSI-H cancers.

scholarly journals Werner syndrome helicase is a selective vulnerability of microsatellite instability-high tumor cells

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Simone Lieb ◽  
Silvia Blaha-Ostermann ◽  
Elisabeth Kamper ◽  
Janine Rippka ◽  
Cornelia Schwarz ◽  
...  
Keyword(s):  
Microsatellite Instability ◽  
Cancer Cells ◽  
Tumor Cells ◽  
Cell Lines ◽  
Cancer Cell ◽  
Werner Syndrome ◽  
Cancer Cell Lines ◽  
Selective Vulnerability ◽  
Functional Screening ◽  
Wrn Helicase

Targeted cancer therapy is based on exploiting selective dependencies of tumor cells. By leveraging recent functional screening data of cancer cell lines we identify Werner syndrome helicase (WRN) as a novel specific vulnerability of microsatellite instability-high (MSI-H) cancer cells. MSI, caused by defective mismatch repair (MMR), occurs frequently in colorectal, endometrial and gastric cancers. We demonstrate that WRN inactivation selectively impairs the viability of MSI-H but not microsatellite stable (MSS) colorectal and endometrial cancer cell lines. In MSI-H cells, WRN loss results in severe genome integrity defects. ATP-binding deficient variants of WRN fail to rescue the viability phenotype of WRN-depleted MSI-H cancer cells. Reconstitution and depletion studies indicate that WRN dependence is not attributable to acute loss of MMR gene function but might arise during sustained MMR-deficiency. Our study suggests that pharmacological inhibition of WRN helicase function represents an opportunity to develop a novel targeted therapy for MSI-H cancers.

scholarly journals Everolimus rescues multiple cellular defects in laminopathy-patient fibroblasts

2018 ◽  
Vol 115 (16) ◽  
pp. 4206-4211 ◽  
Author(s):  
Amanda J. DuBose ◽  
Stephen T. Lichtenstein ◽  
Noreen M. Petrash ◽  
Michael R. Erdos ◽  
Leslie B. Gordon ◽  
...  
Keyword(s):  
Cell Lines ◽  
Mtor Inhibitor ◽  
Werner Syndrome ◽  
Fibroblast Cell ◽  
Cellular Level ◽  
Delayed Senescence ◽  
Progeria Syndrome ◽  
Hutchinson Gilford Progeria Syndrome ◽  
Proliferative Ability ◽  
Fibroblast Cell Lines

LMNA encodes the A-type lamins that are part of the nuclear scaffold. Mutations in LMNA can cause a variety of disorders called laminopathies, including Hutchinson-Gilford progeria syndrome (HGPS), atypical Werner syndrome, and Emery-Dreifuss muscular dystrophy. Previous work has shown that treatment of HGPS cells with the mTOR inhibitor rapamycin or with the rapamycin analog everolimus corrects several of the phenotypes seen at the cellular level—at least in part by increasing autophagy and reducing the amount of progerin, the toxic form of lamin A that is overproduced in HGPS patients. Since other laminopathies also result in production of abnormal and potentially toxic lamin proteins, we hypothesized that everolimus would also be beneficial in those disorders. To test this, we applied everolimus to fibroblast cell lines from six laminopathy patients, each with a different mutation in LMNA. Everolimus treatment increased proliferative ability and delayed senescence in all cell lines. In several cell lines, we observed that with treatment, there is a significant improvement in nuclear blebbing, which is a cellular hallmark of HGPS and other lamin disorders. These preclinical results suggest that everolimus might have clinical benefit for multiple laminopathy syndromes.

scholarly journals Crystal Structure of the Werner’s Syndrome Helicase

2020 ◽  
Author(s):  
Joseph A. Newman ◽  
Angeline E. Gavard ◽  
Simone Lieb ◽  
Madhwesh C. Ravichandran ◽  
Katja Hauer ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structural Information ◽  
Werner Syndrome ◽  
Genome Integrity ◽  
Helicase Domain ◽  
Synthetic Lethal ◽  
Drug Molecules ◽  
Helical Hairpin ◽  
Atp Binding And Hydrolysis ◽  
Wrn Helicase

AbstractWerner syndrome helicase (WRN) plays important roles in multiple pathways of DNA repair and the maintenance of genome integrity. Recently, loss of WRN was identified as a strong synthetic lethal interaction for microsatellite instable (MSI) cancers making WRN a promising drug target. Yet, structural information for the helicase domain is lacking, which prevents structure-based design of drug molecules. In this study, we show that ATP binding and hydrolysis in the helicase domain are required for genome integrity and viability of MSI cancer cells. We then determined the crystal structure of an ADP bound form of the WRN helicase core at 2.2 Å resolution. The structure features an atypical mode of nucleotide binding with extensive contacts formed by motif VI, which in turn defines the relative positioning of the two RecA like domains. The structure features a novel additional β-hairpin in the second RecA and an unusual helical hairpin in the Zn2+ binding domain, and modelling DNA substrates based on existing RecQ DNA complexes suggests roles for these features in the binding of alternative DNA structures. We have further analysed possible interfaces formed from the interactions between the HRDC domain and the helicase core by NMR. Together, this study will facilitate the structure-based design of inhibitors against WRN helicase.

Elevated spontaneous mutation rate in SV40-transformed werner syndrome fibroblast cell lines

1985 ◽  
Vol 11 (3) ◽  
pp. 303-308 ◽  
Author(s):  
Ken-ichiro Fukuchi ◽  
Kiyoji Tanaka ◽  
Jun Nakura ◽  
Yuichi Kumahara ◽  
Tsuyoshi Uchida ◽  
...  
Keyword(s):  
Cell Lines ◽  
Mutation Rate ◽  
Werner Syndrome ◽  
Spontaneous Mutation ◽  
Fibroblast Cell ◽  
Spontaneous Mutation Rate ◽  
Fibroblast Cell Lines

scholarly journals WRN Helicase and FEN-1 Form a Complex upon Replication Arrest and Together Process Branchmigrating DNA Structures Associated with the Replication Fork

2004 ◽  
Vol 15 (2) ◽  
pp. 734-750 ◽  
Author(s):  
Sudha Sharma ◽  
Marit Otterlei ◽  
Joshua A. Sommers ◽  
Henry C. Driscoll ◽  
Grigory L. Dianov ◽  
...  
Keyword(s):  
Genomic Instability ◽  
Replication Fork ◽  
Werner Syndrome ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Premature Aging ◽  
Dependent Manner ◽  
Dna Structures ◽  
Wrn Helicase

Werner Syndrome is a premature aging disorder characterized by genomic instability, elevated recombination, and replication defects. It has been hypothesized that defective processing of certain replication fork structures by WRN may contribute to genomic instability. Fluorescence resonance energy transfer (FRET) analyses show that WRN and Flap Endonuclease-1 (FEN-1) form a complex in vivo that colocalizes in foci associated with arrested replication forks. WRN effectively stimulates FEN-1 cleavage of branch-migrating double-flap structures that are the physiological substrates of FEN-1 during replication. Biochemical analyses demonstrate that WRN helicase unwinds the chicken-foot HJ intermediate associated with a regressed replication fork and stimulates FEN-1 to cleave the unwound product in a structure-dependent manner. These results provide evidence for an interaction between WRN and FEN-1 in vivo and suggest that these proteins function together to process DNA structures associated with the replication fork.

scholarly journals The Werner Syndrome Protein Is Involved in RNA Polymerase II Transcription

1999 ◽  
Vol 10 (8) ◽  
pp. 2655-2668 ◽  
Author(s):  
Adayabalam S. Balajee ◽  
Amrita Machwe ◽  
Alfred May ◽  
Matthew D. Gray ◽  
Junko Oshima ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Cell Lines ◽  
Werner Syndrome ◽  
Molecular Defect ◽  
Rna Pol Ii ◽  
Vitro Assay ◽  
Pol Ii ◽  
Cell Extracts

Werner syndrome (WS) is a human progeroid syndrome characterized by the early onset of a large number of clinical features associated with the normal aging process. The complex molecular and cellular phenotypes of WS involve characteristic features of genomic instability and accelerated replicative senescence. The gene involved (WRN) was recently cloned, and its gene product (WRNp) was biochemically characterized as a helicase. Helicases play important roles in a variety of DNA transactions, including DNA replication, transcription, repair, and recombination. We have assessed the role of the WRN gene in transcription by analyzing the efficiency of basal transcription in WS lymphoblastoid cell lines that carry homozygous WRN mutations. Transcription was measured in permeabilized cells by [3H]UTP incorporation and in vitro by using a plasmid template containing the RNA polymerase II (RNA pol II)–dependent adenovirus major late promoter. With both of these approaches, we find that the transcription efficiency in different WS cell lines is reduced to 40–60% of the transcription in cells from normal individuals. This defect can be complemented by the addition of normal cell extracts to the chromatin of WS cells. Addition of purified wild-type WRNp but not mutated WRNp to the in vitro transcription assay markedly stimulates RNA pol II–dependent transcription carried out by nuclear extracts. A nonhelicase domain (a direct repeat of 27 amino acids) also appears to have a role in transcription enhancement, as revealed by a yeast hybrid–protein reporter assay. This is further supported by the lack of stimulation of transcription when mutant WRNp lacking this domain was added to the in vitro assay. We have thus used several approaches to show a role for WRNp in RNA pol II transcription, possibly as a transcriptional activator. A deficit in either global or regional transcription in WS cells may be a primary molecular defect responsible for the WS clinical phenotype.

scholarly journals WRN Controls Formation of Extrachromosomal Telomeric Circles and Is Required for TRF2ΔB-Mediated Telomere Shortening

2008 ◽  
Vol 28 (6) ◽  
pp. 1892-1904 ◽  
Author(s):  
Baomin Li ◽  
Sonali P. Jog ◽  
Sita Reddy ◽  
Lucio Comai
Keyword(s):  
Werner Syndrome ◽  
Premature Aging ◽  
Specific Factor ◽  
Telomere Shortening ◽  
Protective Function ◽  
Amino Terminal ◽  
Recombination Pathway ◽  
Wrn Helicase ◽  
Mutant Forms ◽  
Circle Formation

ABSTRACT Telomere dysfunction has been proposed to contribute to the pathogenesis of Werner syndrome (WS), a premature-aging disorder. The WS protein WRN binds TRF2, a telomere-specific factor that protects chromosome ends. TRF2 possesses an amino-terminal domain that plays an essential role in preventing telomere shortening, as expression of TRF2ΔB, which lacks this domain, leads to the formation of telomeric circles, telomere shortening, and cell senescence. Our data show that the TRF2ΔB-induced telomeric-loop homologous-recombination pathway requires WRN helicase. In addition, we show that WRN represses the formation of spontaneous telomeric circles, as demonstrated by the increased levels of telomeric circles observed in telomerase-positive WS fibroblasts. The mechanism of circle formation in WS cells does not involve XRCC3 function. Circle formation in WS cells is reduced by reconstitution with wild-type WRN but not mutant forms lacking either exonuclease or helicase activity, demonstrating that both enzymatic activities of WRN are required to suppress telomeric-circle formation in normal cells expressing telomerase reverse transcriptase. Thus, WRN has a key protective function at telomeres which influences telomere topology and inhibits accelerated attrition of telomeres.

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