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British Journal of Cancer Nov 2023High-grade gliomas are primary brain cancers with unacceptably low and persistent survival rates of 10-16 months for WHO grade 4 gliomas over the last 40 years, despite...
BACKGROUND
High-grade gliomas are primary brain cancers with unacceptably low and persistent survival rates of 10-16 months for WHO grade 4 gliomas over the last 40 years, despite surgical resection and DNA-damaging chemo-radiotherapy. More recently, tumour-treating fields therapy (TTFields) has demonstrated modest survival benefit and been clinically approved in several countries. TTFields is thought to mediate anti-cancer activity by primarily disrupting mitosis. However, recent data suggest that TTFields may also attenuate DNA damage repair and replication fork dynamics, providing a potential platform for therapeutic combinations incorporating standard-of-care treatments and targeted DNA damage response inhibitors (DDRi).
METHODS
We have used patient-derived, typically resistant, glioma stem-like cells (GSCs) in combination with the previously validated preclinical Inovitro™ TTFields system together with a number of therapeutic DDRi.
RESULTS
We show that TTFields robustly activates PARP- and ATR-mediated DNA repair (including PARylation and CHK1 phosphorylation, respectively), whilst combining TTFields with PARP1 or ATR inhibitor treatment leads to significantly reduced clonogenic survival. The potency of each of these strategies is further enhanced by radiation treatment, leading to increased amounts of DNA damage with profound delay in DNA damage resolution.
CONCLUSION
To our knowledge, our findings represent the first report of TTFields applied with clinically approved or in-trial DDRi in GSC models and provides a basis for translational studies toward multimodal DDRi/TTFields-based therapeutic strategies for patients with these currently incurable tumours.
Topics: Humans; Glioma; DNA Repair; DNA Damage; Mitosis
PubMed: 37777579
DOI: 10.1038/s41416-023-02454-0 -
Molecular Genetics and Genomics : MGG Sep 2023Hematological malignancies (HM) constitute a variety of cancers originating in blood, bone marrow (BM), and lymphatic systems. During the last two decades, the incidence...
Hematological malignancies (HM) constitute a variety of cancers originating in blood, bone marrow (BM), and lymphatic systems. During the last two decades, the incidence of HM has dramatically increased worldwide. The etiology of HM is still debatable. Genetic instability is a major risk factor for HM. DDR network is a complex signal transduction cellular machinery that detects DNA damage and activates cellular repair factors, thus maintaining genomic integrity. DDR network detects a variety of DNA damage and triggers the activation of cell cycle control, DNA repair, senescence, and apoptosis. Among the DNA repairing pathways, the DNA damage response (DDR) pathway includes DNA damage signaling apparatus such as ATM and ATR genes. ATM tends to detect double-strand breaks (DSBs) while ATR detects single-strand DNA (ssDNA). The study was conducted to observe the expression deregulations of DNA damage response (DDR) pathway genes (ATM, ATR) at mRNA level in 200 blood cancer patients and 200 controls. The real-time PCR was used to analyze the expression of the target genes. The expression results showed statistically significant downregulation of ATM (p < 0.0001) and ATR (p < 0.0001) genes in blood cancer patients vs. controls. Moreover, a significant downregulation of ATM (p < 0.0001) and ATR (p < 0.0001) was obtained in chemotherapy-treated patients vs. healthy controls. The results suggest that dysregulation in ATM and ATR genes may be associated with increased blood cancer risk.
Topics: Humans; Ataxia Telangiectasia Mutated Proteins; Neoplasms; DNA Damage; DNA Repair; DNA; Hematologic Neoplasms
PubMed: 37338595
DOI: 10.1007/s00438-023-02043-z -
Environmental Pollution (Barking, Essex... Dec 2023Bacteria thriving in the mangrove ecosystem are major drivers of elemental cycles. Climate change and environmental stressors (heavy metals) influence the performance of... (Review)
Review
Bacteria thriving in the mangrove ecosystem are major drivers of elemental cycles. Climate change and environmental stressors (heavy metals) influence the performance of these microorganisms, thereby affecting the biogeochemical cycle. The present study reports the genotoxic effect of climatic and heavy metal stressors on mangrove bacteria and their adaptation strategies. Comparative analysis between two bacterial strains, Bacillus stercoris GST-03 and Pseudomonas balearica DST-02 isolated from the Bhitarkanika mangrove ecosystem, Odisha, India, showed cellular injuries in response to various stressors as evident by declined growth, elevated levels of reactive oxygen species (ROS) and resulted DNA damage. B. stercoris GST-03 showed more tolerance towards acidic pH, whereas P. balearica DST-02 showed higher tolerance towards UV exposure and heavy metals (Lead and Cadmium). The adaptation strategies of the strains revealed a significant role of GST in ROS scavenging activity and the involvement of Nucleotide excision repair or SOS response pathways. However, irreparable DNA damage was observed at pH 9 and 200 ppm Cd in B. stercoris GST-03, and at pH 4, 1000 ppm of Pb and 200 ppm of Cd in P. balearica DST-02. The current findings provide a broad overview of bacterial response and adaptability concerning future climate and environmental changes.
Topics: Bacteria; Cadmium; DNA Damage; DNA Repair; Ecosystem; Metals, Heavy; Oxidative Stress; Reactive Oxygen Species
PubMed: 37863253
DOI: 10.1016/j.envpol.2023.122722 -
Toxicology Mechanisms and Methods Nov 2023Furan is an organic chemical that can cause adverse effects on human health and is formed as a result of the thermal decomposition of many food components during...
Furan is an organic chemical that can cause adverse effects on human health and is formed as a result of the thermal decomposition of many food components during cooking, storage, and processing techniques. Studies have shown that exposure to furan causes nephrotoxicity, hepatotoxicity, immunotoxicity, and reproductive toxicity. According to our current knowledge of the literature, the genotoxic mode of action of furan is highly controversial. The genotoxic effects of furan on the male reproductive system, however, have not been studied. In this study, the TM3 Leydig cell line was treated with 750, 1500, and 3000 μM concentrations of furan for 24 h. Following the completion of the exposure period, the cytotoxicity of furan in TM3 Leydig cells was assessed using a cell viability assay and a spectrophotometric measurement of lactate dehydrogenase (LDH) enzyme levels. The double fluorescence staining method was used to demonstrate furan-induced apoptosis, and DNA damage was shown using the micronucleus, comet, and chromosomal aberration assays. The result indicated that furan administration of Leydig cells resulted in an increase in structural chromosomal aberration, comet, and micronucleus formation, reduced cell viability, increased LDH activity, and a higher incidence of apoptotic cells. These findings revealed that furan induces DNA damage in TM3 Leydig cells, causing genotoxicity and DNA damage-induced cytotoxicity.
Topics: Male; Humans; Leydig Cells; DNA Damage; Apoptosis; Chromosome Aberrations; Furans; Comet Assay; Cell Survival
PubMed: 37488932
DOI: 10.1080/15376516.2023.2240884 -
Frontiers in Endocrinology 2023In the complex and dynamic processes of replication, transcription, and translation of DNA molecules, a large number of replication errors or damage can occur which lead... (Review)
Review
In the complex and dynamic processes of replication, transcription, and translation of DNA molecules, a large number of replication errors or damage can occur which lead to obstacles in the development process of germ cells and result in a decreased reproductive rate. DNA damage repair has attracted widespread attention due to its important role in the maintenance and regulation of germ cells. This study reports on a systematic review of the role and mechanism of DNA damage repair in germline development. First, the causes, detection methods, and repair methods of DNA damage, and the mechanism of DNA damage repair are summarized. Second, a summary of the causes of abnormal DNA damage repair in germ cells is introduced along with common examples, and the relevant effects of germ cell damage. Third, we introduce the application of drugs related to DNA damage repair in the treatment of reproductive diseases and related surgical treatment of abnormal DNA damage, and summarize various applications of DNA damage repair in germ cells. Finally, a summary and discussion is given of the current deficiencies in DNA damage repair during germ cell development and future research development. The purpose of this paper is to provide researchers engaged in relevant fields with a further systematic understanding of the relevant applications of DNA damage repair in germ cells and to gain inspiration from it to provide new research ideas for related fields.
Topics: DNA Repair; DNA Damage; Reproduction; Germ Cells; Cell Differentiation
PubMed: 37529603
DOI: 10.3389/fendo.2023.1234280 -
Nature Communications Dec 2023Ubiquitin widely modifies proteins, thereby regulating most cellular functions. The complexity of ubiquitin signalling necessitates unbiased methods enabling global...
Ubiquitin widely modifies proteins, thereby regulating most cellular functions. The complexity of ubiquitin signalling necessitates unbiased methods enabling global detection of dynamic protein ubiquitylation. Here, we describe UBIMAX (UBiquitin target Identification by Mass spectrometry in Xenopus egg extracts), which enriches ubiquitin-conjugated proteins and quantifies regulation of protein ubiquitylation under precise and adaptable conditions. We benchmark UBIMAX by investigating DNA double-strand break-responsive ubiquitylation events, identifying previously known targets and revealing the actin-organizing protein Dbn1 as a major target of DNA damage-induced ubiquitylation. We find that Dbn1 is targeted for proteasomal degradation by the SCF ubiquitin ligase, in a conserved mechanism driven by ATM-mediated phosphorylation of a previously uncharacterized β-Trcp1 degron containing an SQ motif. We further show that this degron is sufficient to induce DNA damage-dependent protein degradation of a model substrate. Collectively, we demonstrate UBIMAX's ability to identify targets of stimulus-regulated ubiquitylation and reveal an SCF-mediated ubiquitylation mechanism controlled directly by the apical DNA damage response kinases.
Topics: Ubiquitin; Actins; Ubiquitination; Signal Transduction; DNA Damage
PubMed: 38097601
DOI: 10.1038/s41467-023-43873-0 -
The Journal of Biological Chemistry Nov 2023Rad18 interacts with the SMC5/6 localization factor 1 (SLF1) to recruit the SMC5/6 complex to DNA damage sites for repair. The mechanism of the specific Rad18...
Rad18 interacts with the SMC5/6 localization factor 1 (SLF1) to recruit the SMC5/6 complex to DNA damage sites for repair. The mechanism of the specific Rad18 recognition by SLF1 is unclear. Here, we present the crystal structure of the tandem BRCT repeat (tBRCT) in SLF1 (SLF1) bound with the interacting Rad18 peptide. Our structure and biochemical studies demonstrate that SLF1 interacts with two phosphoserines and adjacent residues in Rad18 for high-affinity and specificity Rad18 recognition. We found that SLF1 utilizes mechanisms common among tBRCTs as well as unique ones for Rad18 binding, the latter include interactions with an α-helical structure in Rad18 that has not been observed in other tBRCT-bound ligand proteins. Our work provides structural insights into Rad18 targeting by SLF1 and expands the understanding of BRCT-mediated complex assembly.
Topics: Protein Binding; Protein Domains; DNA Damage; Ubiquitin-Protein Ligases; Peptides; DNA Repair
PubMed: 37748650
DOI: 10.1016/j.jbc.2023.105288 -
Current Opinion in Clinical Nutrition... Jul 2024Obesity is associated with increased DNA damage, which may in turn contribute to the development of obesity-related complications. DNA damage can also affect adipocyte... (Review)
Review
PURPOSE OF REVIEW
Obesity is associated with increased DNA damage, which may in turn contribute to the development of obesity-related complications. DNA damage can also affect adipocyte biology, resulting in increased adiposity. Carefully managed weight loss programs can reverse this process. This article surveys new data that support these contentions.
RECENT FINDINGS
Whole exome sequencing analyses have identified rare variants linked to high BMI and adiposity. Two of the identified genes are linked to DNA damage and DNA repair, suggesting that DNA damage itself may play a role in the cause of obesity. It has also been recognized that obesity increases DNA damage in breast tissue of carriers of BRCA mutations and rates of tumour formation in BRCA1+ mice, indicating effect of obesity on cancer development in high-risk populations. In addition, obesity promotes cancer cell chemoresistance by decreasing fatty acid oxidation involved in cellular DNA damage response, leading to apoptotic cellular death. Obesity is also associated with a reduced capacity of oocytes to repair sperm DNA damage, leading to lower in-vitro fertilization rates in women with obesity.
SUMMARY
DNA damage and cellular responses to DNA damage can be both the result and the cause of obesity and can strongly influence the development and treatment of obesity-associated diseases.
Topics: Humans; Obesity; DNA Damage; Animals; DNA Repair; Female; Body Mass Index; Neoplasms; Male; Mice; Adiposity
PubMed: 38652557
DOI: 10.1097/MCO.0000000000001038 -
International Journal of Molecular... Feb 2024The DNA damage response (DDR) system is a complicated network of signaling pathways that detects and repairs DNA damage or induces apoptosis. Critical regulators of the... (Review)
Review
The DNA damage response (DDR) system is a complicated network of signaling pathways that detects and repairs DNA damage or induces apoptosis. Critical regulators of the DDR network include the DNA damage kinases ataxia telangiectasia mutated Rad3-related kinase (ATR) and ataxia-telangiectasia mutated (ATM). The ATR pathway coordinates processes such as replication stress response, stabilization of replication forks, cell cycle arrest, and DNA repair. ATR inhibition disrupts these functions, causing a reduction of DNA repair, accumulation of DNA damage, replication fork collapse, inappropriate mitotic entry, and mitotic catastrophe. Recent data have shown that the inhibition of ATR can lead to synthetic lethality in ATM-deficient malignancies. In addition, ATR inhibition plays a significant role in the activation of the immune system by increasing the tumor mutational burden and neoantigen load as well as by triggering the accumulation of cytosolic DNA and subsequently inducing the cGAS-STING pathway and the type I IFN response. Taken together, we review stimulating data showing that ATR kinase inhibition can alter the DDR network, the immune system, and their interplay and, therefore, potentially provide a novel strategy to improve the efficacy of antitumor therapy, using ATR inhibitors as monotherapy or in combination with genotoxic drugs and/or immunomodulators.
Topics: Humans; Ataxia Telangiectasia Mutated Proteins; DNA Repair; Neoplasms; DNA Damage; Treatment Outcome
PubMed: 38474014
DOI: 10.3390/ijms25052767 -
Nano Letters Jul 2023Therapy-induced DNA damage is the most common strategy to inhibit tumor cell proliferation, but the therapeutic efficacy is limited by DNA repair machinery. Carrier-free...
Therapy-induced DNA damage is the most common strategy to inhibit tumor cell proliferation, but the therapeutic efficacy is limited by DNA repair machinery. Carrier-free nanoproteolysis targeting chimeras (PROTACs), designed as SDNpros, have been developed to enhance photodynamic therapy (PDT) by blocking the DNA damage repair pathway through BRD4 degradation. Specifically, SDNpros are constructed through noncovalent interactions between the photosensitizer of chlorine e6 (Ce6) and PROTACs of BRD4 degrader (dBET57) via self-assembly. SDNpro has favorable dispersibility and a uniform nanosize distribution without drug excipients. Upon light irradiation, SDNpro produces abundant reactive oxygen species (ROS) to induce DNA oxidative damage. Meanwhile, the DNA repair pathway would be interrupted by the concurrent degradation of BRD4, which could intensify the oxidative DNA damage and elevate PDT efficiency. Beneficially, SDNpro suppresses tumor growth and avoids systemic side effects, providing a promising strategy to promote the clinical translation of PROTACs for tumor treatment.
Topics: Nuclear Proteins; Excipients; Cell Line, Tumor; Transcription Factors; Photosensitizing Agents; Photochemotherapy; DNA Damage; Porphyrins; Nanoparticles
PubMed: 37387510
DOI: 10.1021/acs.nanolett.3c01812