scholarly journals Human RAD51 paralogue, SWSAP1, fosters RAD51 filament by regulating the anti-recombinase, FIGNL1 AAA+ ATPase

2018 ◽  
Author(s):  
Kenichiro Matsuzaki ◽  
Shizuka Kondo ◽  
Tatsuya Ishikawa ◽  
Akira Shinohara
Keyword(s):  
Dna Damage ◽  
Genomic Stability ◽  
Interacting Proteins ◽  
Aaa Atpase ◽  
Filament Dynamics ◽  
Differential Control ◽  
Mitosis And Meiosis ◽  
Breast Cancer Gene ◽  
Human Rad51

SummaryRAD51 assembly on single-stranded (ss)DNAs is a crucial step in the homology-dependent repair of DNA damage for genomic stability. The formation of the RAD51 filament is tightly regulated by various RAD51-interacting proteins. The familial breast cancer gene, BRCA2, as well as RAD52 and six RAD51 paralogues (SWSAP1, RAD51B, RAD51C, RAD51D, XRCC2, and XRCC3) promote RAD51 assembly on ssDNAs in humans. However, the mechanisms underlying the differential control of RAD51 filament dynamics by these factors remain largely unknown. Here, we report a role for the human RAD51 paralogue, SWSAP1, as a novel regulator of RAD51 assembly. Swsap1-deficient cells show defects in DNA damage-induced RAD51 assembly during both mitosis and meiosis. Defective RAD51 assembly in SWSAP1-depleted cells is suppressed by the depletion of FIGNL1, an AAA+ ATPase, which binds to RAD51 as well as SWSAP1. Purified FIGNL1 promotes the dissociation of RAD51 from ssDNAs. The in vitro dismantling activity of FIGNL1 does not require its ATPase but depends on RAD51-binding, suggesting a novel mechanism of RAD51 filament remodelling. Purified SWSAP1 inhibits the RAD51-dismantling activity of FIGNL1. Taken together, our data suggest that SWSAP1 protects RAD51 filaments by antagonizing the anti-recombinase, FIGNL1.

CBIO-13. THOC1 DRIVES GBM AGGRESSION THROUGH MODULATION OF R-LOOPS AND GENOMIC STABILITY

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi29-vi30
Author(s):  
Shreya Budhiraja ◽  
Shivani Baisiwala ◽  
Khizar Nandoliya ◽  
Li Chen ◽  
Crismita Dmello ◽  
...  
Keyword(s):  
Stem Cells ◽  
Dna Damage ◽  
Neural Stem Cells ◽  
Histone Deacetylase ◽  
Genomic Stability ◽  
Loop Formation ◽  
Driver Genes ◽  
A Genome

Abstract Glioblastoma (GBM) is the most aggressive and common type of adult malignant brain tumor, with a median survival of only 21 months. To identify which genes drive its highly aggressive phenotype, we performed a genome-wide CRISPR-Cas9 knockout screen. Results showed substantial enrichment of ~160 novel essential oncogenic driver genes and pathways, including a previously unstudied gene THOC1—involved in RNA processing—that showed significant elevations in expression at RNA and protein levels (p< 0.05) in GBM, as well as a significant survival benefit in patient datasets when downregulated (p< 0.05). Knocking out THOC1 resulted in cell death in multiple GBM patient-derived xenograft (PDX) lines and extended survival compared to the controls (p< 0.01) in vivo. Overexpression of THOC1 in neural stem cells resulted in transformation to a cancerous phenotype, as evidenced by sphere formation in a soft agar assay (p< 0.01) and in vivo tumor engraftment assays. Further investigation of THOC1 through immunoprecipitation in neural stem cells and multiple GBM lines showed significant interaction in GBM with histone deacetylase complex SIN3A, involved in recruiting major histone deacetylases in order to close the DNA and prevent the accumulation of R-loops, RNA:DNA hybrids that pose a threat to genomic stability. Additional investigation revealed that THOC1-knockdowns in vitro induced R-loop formation and DNA damage, while THOC1-overexpression in vitro resulted in an untenable decrease in R-loops and DNA damage, suggesting that the THOC1-SIN3A axis is elevated in GBM in order to prevent the accumulation of genotoxic R-loops. Additionally, histone deacetylase activity was shown to be elevated in THOC1-overexpression conditions and reduced in THOC1-knockdown conditions, confirming that the THOC1-SIN3A axis functions to prevent R-loop accumulation through the epigenetic regulation. In summary, our whole-genome CRISPR-Cas9 knockout screen has identified a promising therapeutic target for GBM—a disease desperately in need of therapeutic innovations.

scholarly journals Current Knowledge on Honey and Its Derivatives with Genomic Stability: A Mini Review

2017 ◽  
Vol 9 (13) ◽  
pp. 145
Author(s):  
Malisanurhidayu Yaacob ◽  
Anne Jesscy Stanis ◽  
Nor Fadilah Rajab ◽  
Suzana Shahar ◽  
Razinah Sharif
Keyword(s):  
Dna Damage ◽  
Honey Bee ◽  
Royal Jelly ◽  
Current Knowledge ◽  
Genomic Stability ◽  
Research Field ◽  
Search Term ◽  
Bee Pollen

Genome health is an important factor that plays a role in various degenerative diseases. Instability of genome is the prevalence of mutation within the genome such as changed in nucleic acid and chromosomal arrangement and also the presence of abnormal number of chromosome in cell. Therefore, several method were used to overcome this problem and one of them is by using natural product such as honey, propolis, bee pollen and royal jelly that is high in antioxidant. Those are products that derive from honey bee and had been used as food supplement to increase the quality of life. Therefore, this systematic review provides the updates on the potential of honey bee products to decrease DNA damage both in in vivo and in vitro approaches. Search term of “honey”, “propolis”, “bee pollen”, royal jelly”, “DNA damage”, “genome integrity”, and “telomere” were used for searching purpose in three databases (Scopus, Pubmed and Medline) and also Google Scholar. All the published articles were assessed using PRISMA guidelines and finally after the eligibility process, only 34 published articles were selected for this review. Based on the reports, the product from the honey bee decrease the genome related diseases by reducing the accumulation of free radical, increase the DNA repair protein expression and decrease the telomerase activity in the cell. This provides a large gap in the research field focusing on the effect of those derivatives from bees on genomic stability.

Bestimmung der DNA-Schädigung in vitro

2010 ◽  
Vol 49 (S 01) ◽  
pp. S64-S68
Author(s):  
E. Dikomey
Keyword(s):  
Dna Damage ◽  
Cell Lines ◽  
Chromosome Aberrations ◽  
Genetic Factors ◽  
Double Strand Breaks ◽  
Strand Breaks ◽  
Cell Inactivation ◽  
Repair Mechanisms ◽  
Break Repair

SummaryIonising irradiation acts primarily via induction of DNA damage, among which doublestrand breaks are the most important lesions. These lesions may lead to lethal chromosome aberrations, which are the main reason for cell inactivation. Double-strand breaks can be repaired by several different mechanisms. The regulation of these mechanisms appears be fairly different for normal and tumour cells. Among different cell lines capacity of doublestrand break repair varies by only few percents and is known to be determined mostly by genetic factors. Knowledge about doublestrand break repair mechanisms and their regulation is important for the optimal application of ionising irradiation in medicine.

A Novel Camptothecin Derivative 3j Inhibits Nsclc Proliferation Via Induction of Cell Cycle Arrest By Topo I-Mediated DNA Damage

2019 ◽  
Vol 19 (3) ◽  
pp. 365-374 ◽  
Author(s):  
Yang Liu ◽  
Jingyin Zhang ◽  
Shuyun Feng ◽  
Tingli Zhao ◽  
Zhengzheng Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Flow Cytometry ◽  
Dna Damage ◽  
Cyclin D ◽  
Dna Relaxation ◽  
Cycle Arrest ◽  
H460 Cell ◽  
H1975 Cell

Objective: The aim of this study is to investigate the inhibitory effect of camptothecin derivative 3j on Non-Small Cell Lung Cancer (NSCLCs) cells and the potential anti-tumor mechanisms. Background: Camptothecin compounds are considered as the third largest natural drugs which are widely investigated in the world and they suffered restriction because of serious toxicity, such as hemorrhagic cystitis and bone marrow suppression. Methods: Using cell proliferation assay and S180 tumor mice model, a series of 20(S)-O-substituted benzoyl 7- ethylcamptothecin compounds were screened and evaluated the antitumor activities in vitro and in vivo. Camptothecin derivative 3j was selected for further study using flow cytometry in NSCLCs cells. Cell cycle related protein cyclin A2, CDK2, cyclin D and cyclin E were detected by Western Blot. Then, computer molecular docking was used to confirm the interaction between 3j and Topo I. Also, DNA relaxation assay and alkaline comet assay were used to investigate the mechanism of 3j on DNA damage. Results: Our results demonstrated that camptothecin derivative 3j showed a greater antitumor effect in eleven 20(S)-O-substituted benzoyl 7-ethylcamptothecin compounds in vitro and in vivo. The IC50 of 3j was 1.54± 0.41 µM lower than irinotecan with an IC50 of 13.86±0.80 µM in NCI-H460 cell, which was reduced by 8 fold. In NCI-H1975 cell, the IC50 of 3j was 1.87±0.23 µM lower than irinotecan (IC50±SD, 5.35±0.38 µM), dropped by 1.8 fold. Flow cytometry analysis revealed that 3j induced significant accumulation in a dose-dependent manner. After 24h of 3j (10 µM) treatment, the percentage of NCI-H460 cell in S-phase significantly increased (to 93.54 ± 4.4%) compared with control cells (31.67 ± 3.4%). Similarly, the percentage of NCI-H1975 cell in Sphase significantly increased (to 83.99 ± 2.4%) compared with control cells (34.45 ± 3.9%) after treatment with 10µM of 3j. Moreover, increased levels of cyclin A2, CDK2, and decreased levels of cyclin D, cyclin E further confirmed that cell cycle arrest was induced by 3j. Furthermore, molecular docking studies suggested that 3j interacted with Topo I-DNA and DNA-relaxation assay simultaneously confirmed that 3j suppressed the activity of Topo I. Research on the mechanism showed that 3j exhibited anti-tumour activity via activating the DNA damage response pathway and suppressing the repair pathway in NSCLC cells. Conclusion: Novel camptothecin derivative 3j has been demonstrated as a promising antitumor agent and remains to be assessed in further studies.

scholarly journals CX-5461 Enhances the Efficacy of APR-246 via Induction of DNA Damage and Replication Stress in Triple-Negative Breast Cancer

2021 ◽  
Vol 22 (11) ◽  
pp. 5782
Author(s):  
Ashwini Makhale ◽  
Devathri Nanayakkara ◽  
Prahlad Raninga ◽  
Kum Kum Khanna ◽  
Murugan Kalimutho
Keyword(s):  
Breast Cancer ◽  
Dna Damage ◽  
Triple Negative Breast Cancer ◽  
Combination Treatment ◽  
Triple Negative ◽  
Annexin V ◽  
Replication Stress ◽  
Breast Cancer Cell Lines ◽  
Combination Strategy

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer lacking targeted therapy. Here, we evaluated the anti-cancer activity of APR-246, a P53 activator, and CX-5461, a RNA polymerase I inhibitor, in the treatment of TNBC cells. We tested the efficacy of individual and combination therapy of CX-5461 and APR-246 in vitro, using a panel of breast cancer cell lines. Using publicly available breast cancer datasets, we found that components of RNA Pol I are predominately upregulated in basal-like breast cancer, compared to other subtypes, and this upregulation is associated with poor overall and relapse-free survival. Notably, we found that the treatment of breast cancer cells lines with CX-5461 significantly hampered cell proliferation and synergistically enhanced the efficacy of APR-246. The combination treatment significantly induced apoptosis that is associated with cleaved PARP and Caspase 3 along with Annexin V positivity. Likewise, we also found that combination treatment significantly induced DNA damage and replication stress in these cells. Our data provide a novel combination strategy by utilizing APR-246 in combination CX-5461 in killing TNBC cells that can be further developed into more effective therapy in TNBC therapeutic armamentarium.

scholarly journals Identification of New Markers of Alcohol-Derived DNA Damage in Humans

Biomolecules ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 366
Author(s):  
Valeria Guidolin ◽  
Erik S. Carlson ◽  
Andrea Carrà ◽  
Peter W. Villalta ◽  
Laura A. Maertens ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Adducts ◽  
Neutral Loss ◽  
Alcohol Exposure ◽  
Dose Dependence ◽  
Accurate Mass ◽  
Constant Neutral Loss ◽  
Covalent Modifications ◽  
Underlying Mechanisms

Alcohol consumption is a risk factor for the development of several cancers, including those of the head and neck and the esophagus. The underlying mechanisms of alcohol-induced carcinogenesis remain unclear; however, at these sites, alcohol-derived acetaldehyde seems to play a major role. By reacting with DNA, acetaldehyde generates covalent modifications (adducts) that can lead to mutations. Previous studies have shown a dose dependence between levels of a major acetaldehyde-derived DNA adduct and alcohol exposure in oral-cell DNA. The goal of this study was to optimize a mass spectrometry (MS)-based DNA adductomic approach to screen for all acetaldehyde-derived DNA adducts to more comprehensively characterize the genotoxic effects of acetaldehyde in humans. A high-resolution/-accurate-mass data-dependent constant-neutral-loss-MS3 methodology was developed to profile acetaldehyde-DNA adducts in purified DNA. This resulted in the identification of 22 DNA adducts. In addition to the expected N2-ethyldeoxyguanosine (after NaBH3CN reduction), two previously unreported adducts showed prominent signals in the mass spectra. MSn fragmentation spectra and accurate mass were used to hypothesize the structure of the two new adducts, which were then identified as N6-ethyldeoxyadenosine and N4-ethyldeoxycytidine by comparison with synthesized standards. These adducts were quantified in DNA isolated from oral cells collected from volunteers exposed to alcohol, revealing a significant increase after the exposure. In addition, 17 of the adducts identified in vitro were detected in these samples confirming our ability to more comprehensively characterize the DNA damage deriving from alcohol exposures.

Protective effect of argan oil on DNA damage in vivo and in vitro

Biomarkers ◽  
2021 ◽  
pp. 1-9
Author(s):  
Habiba Bouchab ◽  
Abbas Ishaq ◽  
Riad EL Kebbaj ◽  
Boubker Nasser ◽  
Gabriele Saretzki
Keyword(s):  
Dna Damage ◽  
Protective Effect ◽  
Argan Oil
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