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Chemical Research in Toxicology Jul 2023Aldehydes are widespread in the environment, with multiple sources such as food and beverages, industrial effluents, cigarette smoke, and additives. The toxic effects of... (Review)
Review
Aldehydes are widespread in the environment, with multiple sources such as food and beverages, industrial effluents, cigarette smoke, and additives. The toxic effects of exposure to several aldehydes have been observed in numerous studies. At the molecular level, aldehydes damage DNA, cross-link DNA and proteins, lead to lipid peroxidation, and are associated with increased disease risk including cancer. People genetically predisposed to aldehyde sensitivity exhibit severe health outcomes. In various diseases such as Fanconi's anemia and Cockayne syndrome, loss of aldehyde-metabolizing pathways in conjunction with defects in DNA repair leads to widespread DNA damage. Importantly, aldehyde-associated mutagenicity is being explored in a growing number of studies, which could offer key insights into how they potentially contribute to tumorigenesis. Here, we review the genotoxic effects of various aldehydes, focusing particularly on the DNA adducts underlying the mutagenicity of environmentally derived aldehydes. We summarize the chemical structures of the aldehydes and their predominant DNA adducts, discuss various methodologies, and , commonly used in measuring aldehyde-associated mutagenesis, and highlight some recent studies looking at aldehyde-associated mutation signatures and spectra. We conclude the Review with a discussion on the challenges and future perspectives of investigating aldehyde-associated mutagenesis.
Topics: Humans; Aldehydes; DNA Adducts; DNA Damage; DNA Repair; Mutagens; DNA
PubMed: 37363863
DOI: 10.1021/acs.chemrestox.3c00045 -
Bioscience Reports Oct 2023Radiotherapy is utilised in the treatment of ∼50% of all human cancers, which predominantly employs photon radiation. However, particle radiotherapy elicits... (Review)
Review
Radiotherapy is utilised in the treatment of ∼50% of all human cancers, which predominantly employs photon radiation. However, particle radiotherapy elicits significant benefits over conventional photons due to more precise dose deposition and increased linear energy transfer (LET) that generates an enhanced therapeutic response. Specifically, proton beam therapy (PBT) and carbon ion radiotherapy (CIRT) are characterised by a Bragg peak, which generates a low entrance radiation dose, with the majority of the energy deposition being defined within a small region which can be specifically targeted to the tumour, followed by a low exit dose. PBT is deemed relatively low-LET whereas CIRT is more densely ionising and therefore high LET. Despite the radiotherapy type, tumour cell killing relies heavily on the introduction of DNA damage that overwhelms the repair capacity of the tumour cells. It is known that DNA damage complexity increases with LET that leads to enhanced biological effectiveness, although the specific DNA repair pathways that are activated following the different radiation sources is unclear. This knowledge is required to determine whether specific proteins and enzymes within these pathways can be targeted to further increase the efficacy of the radiation. In this review, we provide an overview of the different radiation modalities and the DNA repair pathways that are responsive to these. We also provide up-to-date knowledge of studies examining the impact of LET and DNA damage complexity on DNA repair pathway choice, followed by evidence on how enzymes within these pathways could potentially be therapeutically exploited to further increase tumour radiosensitivity, and therefore radiotherapy efficacy.
Topics: Humans; DNA Damage; Radiation, Ionizing; Neoplasms; Photons; Radiation Tolerance
PubMed: 37695845
DOI: 10.1042/BSR20222586 -
Genes Jun 2023Cells are constantly assaulted by endogenous and exogenous sources of DNA damage that threaten genome stability [...].
Cells are constantly assaulted by endogenous and exogenous sources of DNA damage that threaten genome stability [...].
Topics: Humans; DNA Repair; DNA Damage; Genomic Instability
PubMed: 37510290
DOI: 10.3390/genes14071385 -
Nature Communications Sep 2023The SUMO protease SENP6 maintains genomic stability, but mechanistic understanding of this process remains limited. We find that SENP6 deconjugates SUMO2/3 polymers on a...
The SUMO protease SENP6 maintains genomic stability, but mechanistic understanding of this process remains limited. We find that SENP6 deconjugates SUMO2/3 polymers on a group of DNA damage response proteins, including BRCA1-BARD1, 53BP1, BLM and ERCC1-XPF. SENP6 maintains these proteins in a hypo-SUMOylated state under unstressed conditions and counteracts their polySUMOylation after hydroxyurea-induced stress. Co-depletion of RNF4 leads to a further increase in SUMOylation of BRCA1, BARD1 and BLM, suggesting that SENP6 antagonizes targeting of these proteins by RNF4. Functionally, depletion of SENP6 results in uncoordinated recruitment and persistence of SUMO2/3 at UVA laser and ionizing radiation induced DNA damage sites. Additionally, SUMO2/3 and DNA damage response proteins accumulate in nuclear bodies, in a PML-independent manner driven by multivalent SUMO-SIM interactions. These data illustrate coordinated regulation of SUMOylated DNA damage response proteins by SENP6, governing their timely localization at DNA damage sites and nuclear condensation state.
Topics: Cysteine Proteases; Peptide Hydrolases; DNA Damage; Endopeptidases; Hydroxyurea
PubMed: 37735495
DOI: 10.1038/s41467-023-41623-w -
Cellular Oncology (Dordrecht) Dec 2023The transcription factor NF-E2-related factor 2 (NRF2) is a master regulator widely involved in essential cellular functions such as DNA repair. By clarifying the... (Review)
Review
PURPOSE
The transcription factor NF-E2-related factor 2 (NRF2) is a master regulator widely involved in essential cellular functions such as DNA repair. By clarifying the upstream and downstream links of NRF2 to DNA damage repair, we hope that attention will be drawn to the utilization of NRF2 as a target for cancer therapy.
METHODS
Query and summarize relevant literature on the role of NRF2 in direct repair, BER, NER, MMR, HR, and NHEJ in pubmed. Make pictures of Roles of NRF2 in DNA Damage Repair and tables of antioxidant response elements (AREs) of DNA repair genes. Analyze the mutation frequency of NFE2L2 in different types of cancer using cBioPortal online tools. By using TCGA, GTEx and GO databases, analyze the correlation between NFE2L2 mutations and DNA repair systems as well as the degree of changes in DNA repair systems as malignant tumors progress.
RESULTS
NRF2 plays roles in maintaining the integrity of the genome by repairing DNA damage, regulating the cell cycle, and acting as an antioxidant. And, it possibly plays roles in double stranded break (DSB) pathway selection following ionizing radiation (IR) damage. Whether pathways such as RNA modification, ncRNA, and protein post-translational modification affect the regulation of NRF2 on DNA repair is still to be determined. The overall mutation frequency of the NFE2L2 gene in esophageal carcinoma, lung cancer, and penile cancer is the highest. Genes (50 of 58) that are negatively correlated with clinical staging are positively correlated with NFE2L2 mutations or NFE2L2 expression levels.
CONCLUSION
NRF2 participates in a variety of DNA repair pathways and plays important roles in maintaining genome stability. NRF2 is a potential target for cancer treatment.
Topics: Humans; NF-E2-Related Factor 2; DNA Repair; DNA Damage; Mutation; Genomic Instability
PubMed: 37365451
DOI: 10.1007/s13402-023-00834-5 -
Virology Journal Nov 2023The DNA damage response (DDR) is a signaling cascade that is triggered by DNA damage, involving the halting of cell cycle progression and repair. It is a key event... (Review)
Review
The DNA damage response (DDR) is a signaling cascade that is triggered by DNA damage, involving the halting of cell cycle progression and repair. It is a key event leading to senescence, which is characterized by irreversible cell cycle arrest and the senescence-associated secretory phenotype (SASP) that includes the expression of inflammatory cytokines. Human cytomegalovirus (HCMV) is a ubiquitous pathogen that plays an important role in the senescence process. It has been established that DDR is necessary for HCMV to replicate effectively. This paper reviews the relationship between DDR, cellular senescence, and HCMV, providing new sights for virus-induced senescence (VIS).
Topics: Humans; Cytomegalovirus; Cellular Senescence; Signal Transduction; Cell Cycle Checkpoints; DNA Damage
PubMed: 37915066
DOI: 10.1186/s12985-023-02203-y -
Editorial for the 'Reciprocal Links between RNA Metabolism and DNA Damage' Special Issue: July 2023.Genes Aug 2023Two central parts of molecular biology are the control of genome integrity and genome expression [...].
Two central parts of molecular biology are the control of genome integrity and genome expression [...].
Topics: Molecular Biology; DNA Damage; RNA
PubMed: 37628622
DOI: 10.3390/genes14081570 -
Andrology Nov 2023This review surveys the causes and consequences of DNA damage in the male germ line from spermatogonial stem cells to fully differentiated spermatozoa. Within the stem... (Review)
Review
This review surveys the causes and consequences of DNA damage in the male germ line from spermatogonial stem cells to fully differentiated spermatozoa. Within the stem cell population, DNA integrity is well maintained as a result of excellent DNA surveillance and repair; however, a progressive increase in background mutation rates does occur with paternal age possibly as a result of aberrant DNA repair as well as replication error. Once a germ cell has committed to spermatogenesis, it responds to genetic damage via a range of DNA repair pathways or, if this process fails, by the induction of apoptosis. When fully-differentiated spermatozoa are stressed, they also activate a truncated intrinsic apoptotic pathway which results in the activation of nucleases in the mitochondria and cytoplasm; however, the physical architecture of these cells prevents these enzymes from translocating to the nucleus to induce DNA fragmentation. Conversely, hydrogen peroxide released from the sperm midpiece during apoptosis is able to penetrate the nucleus and induce DNA damage. The base excision repair pathway responds to such damage by cleaving oxidized bases from the DNA, leaving abasic sites that are alkali-labile and readily detected with the comet assay. As levels of oxidative stress increase and these cells enter the perimortem, topoisomerase integrated into the sperm chromatin becomes activated by SUMOylation. Such activation may initially facilitate DNA repair by reannealing double strand breaks but ultimately prepares the DNA for destruction by nucleases released from the male reproductive tract. The abasic sites and oxidized base lesions found in live spermatozoa are mutagenic and may increase the mutational load carried by the offspring, particularly in the context of assisted conception. A variety of strategies are described for managing patients expressing high levels of DNA damage in their spermatozoa, to reduce the risks such lesions might pose to offspring health.
Topics: Male; Humans; Semen; Spermatozoa; Testis; DNA Damage; DNA
PubMed: 36604857
DOI: 10.1111/andr.13375 -
International Journal of Molecular... Nov 2023Replicative DNA polymerases are blocked by nearly all types of DNA damage. The resulting DNA replication stress threatens genome stability. DNA replication stress is... (Review)
Review
Replicative DNA polymerases are blocked by nearly all types of DNA damage. The resulting DNA replication stress threatens genome stability. DNA replication stress is also caused by depletion of nucleotide pools, DNA polymerase inhibitors, and DNA sequences or structures that are difficult to replicate. Replication stress triggers complex cellular responses that include cell cycle arrest, replication fork collapse to one-ended DNA double-strand breaks, induction of DNA repair, and programmed cell death after excessive damage. Replication stress caused by specific structures (e.g., G-rich sequences that form G-quadruplexes) is localized but occurs during the S phase of every cell division. This review focuses on cellular responses to widespread stress such as that caused by random DNA damage, DNA polymerase inhibition/nucleotide pool depletion, and R-loops. Another form of global replication stress is seen in cancer cells and is termed oncogenic stress, reflecting dysregulated replication origin firing and/or replication fork progression. Replication stress responses are often dysregulated in cancer cells, and this too contributes to ongoing genome instability that can drive cancer progression. Nucleases play critical roles in replication stress responses, including MUS81, EEPD1, Metnase, CtIP, MRE11, EXO1, DNA2-BLM, SLX1-SLX4, XPF-ERCC1-SLX4, Artemis, XPG, FEN1, and TATDN2. Several of these nucleases cleave branched DNA structures at stressed replication forks to promote repair and restart of these forks. We recently defined roles for EEPD1 in restarting stressed replication forks after oxidative DNA damage, and for TATDN2 in mitigating replication stress caused by R-loop accumulation in BRCA1-defective cells. We also discuss how insights into biological responses to genome-wide replication stress can inform novel cancer treatment strategies that exploit synthetic lethal relationships among replication stress response factors.
Topics: Humans; DNA Replication; DNA Repair; DNA Damage; Endonucleases; Genomic Instability; DNA; Nucleotides
PubMed: 38069223
DOI: 10.3390/ijms242316903 -
Current Opinion in Structural Biology Aug 2023The replication machinery frequently encounters DNA damage and other structural impediments that inhibit progression of the replication fork. Replication-coupled... (Review)
Review
The replication machinery frequently encounters DNA damage and other structural impediments that inhibit progression of the replication fork. Replication-coupled processes that remove or bypass the barrier and restart stalled forks are essential for completion of replication and for maintenance of genome stability. Errors in replication-repair pathways lead to mutations and aberrant genetic rearrangements and are associated with human diseases. This review highlights recent structures of enzymes involved in three replication-repair pathways: translesion synthesis, template switching and fork reversal, and interstrand crosslink repair.
Topics: Humans; DNA Damage; DNA Repair; DNA Replication; Mutation; Genomic Instability
PubMed: 37269798
DOI: 10.1016/j.sbi.2023.102618