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Redox Biology Apr 2017Rare pleiotropic genetic disorders, Ataxia-telangiectasia (A-T), Bloom syndrome (BS) and Nijmegen breakage syndrome (NBS) are characterised by immunodeficiency, extreme... (Review)
Review
Rare pleiotropic genetic disorders, Ataxia-telangiectasia (A-T), Bloom syndrome (BS) and Nijmegen breakage syndrome (NBS) are characterised by immunodeficiency, extreme radiosensitivity, higher cancer susceptibility, premature aging, neurodegeneration and insulin resistance. Some of these functional abnormalities can be explained by aberrant DNA damage response and chromosomal instability. It has been suggested that one possible common denominator of these conditions could be chronic oxidative stress caused by endogenous ROS overproduction and impairment of mitochondrial homeostasis. Recent studies indicate new, alternative sources of oxidative stress in A-T, BS and NBS cells, including NADPH oxidase 4 (NOX4), oxidised low-density lipoprotein (ox-LDL) or Poly (ADP-ribose) polymerases (PARP). Mitochondrial abnormalities such as changes in the ultrastructure and function of mitochondria, excess mROS production as well as mitochondrial damage have also been reported in A-T, BS and NBS cells. A-T, BS and NBS cells are inextricably linked to high levels of reactive oxygen species (ROS), and thereby, chronic oxidative stress may be a major phenotypic hallmark in these diseases. Due to the presence of mitochondrial disturbances, A-T, BS and NBS may be considered mitochondrial diseases. Excess activity of antioxidant enzymes and an insufficient amount of low molecular weight antioxidants indicate new pharmacological strategies for patients suffering from the aforementioned diseases. However, at the current stage of research we are unable to ascertain if antioxidants and free radical scavengers can improve the condition or prolong the survival time of A-T, BS and NBS patients. Therefore, it is necessary to conduct experimental studies in a human model.
Topics: Ataxia Telangiectasia; Bloom Syndrome; DNA Damage; DNA Repair; Gene Expression Regulation; Humans; Lipoproteins, LDL; Mitochondria; NADPH Oxidase 4; Nijmegen Breakage Syndrome; Oxidative Stress; Poly(ADP-ribose) Polymerases; Reactive Oxygen Species; Signal Transduction
PubMed: 28063379
DOI: 10.1016/j.redox.2016.12.030 -
BioEssays : News and Reviews in... Sep 2017The functions of the Bloom syndrome helicase (BLM) and its orthologs are well characterized in mitotic DNA damage repair, but their roles within the context of meiotic... (Review)
Review
The functions of the Bloom syndrome helicase (BLM) and its orthologs are well characterized in mitotic DNA damage repair, but their roles within the context of meiotic recombination are less clear. In meiotic recombination, multiple repair pathways are used to repair meiotic DSBs, and current studies suggest that BLM may regulate the use of these pathways. Based on literature from Saccharomyces cerevisiae, Arabidopsis thaliana, Mus musculus, Drosophila melanogaster, and Caenorhabditis elegans, we present a unified model for a critical meiotic role of BLM and its orthologs. In this model, BLM and its orthologs utilize helicase activity to regulate the use of various pathways in meiotic recombination by continuously disassembling recombination intermediates. This unwinding activity provides the meiotic program with a steady pool of early recombination substrates, increasing the probability for a DSB to be processed by the appropriate pathway. As a result of BLM activity, crossovers are properly placed throughout the genome, promoting proper chromosomal disjunction at the end of meiosis. This unified model can be used to further refine the complex role of BLM and its orthologs in meiotic recombination.
Topics: Animals; Bloom Syndrome; Chromosomes; DNA Helicases; DNA Repair; Humans; Meiosis; RecQ Helicases; Recombination, Genetic
PubMed: 28792069
DOI: 10.1002/bies.201700073 -
Seminars in Hematology Apr 2017The majority of myeloid malignancies are caused by sporadic somatic events rather than cancer predisposition. Nonetheless, the identification of hereditary cancer... (Review)
Review
The majority of myeloid malignancies are caused by sporadic somatic events rather than cancer predisposition. Nonetheless, the identification of hereditary cancer predisposition syndromes is critical when caring for patients with myeloid malignancies since detection may direct decisions related to cancer treatment and surveillance. A positive genetic test result also has important implications for other family members who can use this information to undergo their own testing to determine their cancer risk. We review the demographics, genetic mechanisms of disease, diagnostic approach, malignancy risk, and management for the following five cancer predisposition syndromes associated with myeloid malignancies: Li-Fraumeni, constitutional mismatch repair deficiency, Werner, Bloom, and Nijmegen breakage.
Topics: Genetic Predisposition to Disease; Germ-Line Mutation; Hematologic Neoplasms; Humans; Leukemia, Myeloid, Acute; Myeloproliferative Disorders; Syndrome
PubMed: 28637615
DOI: 10.1053/j.seminhematol.2017.04.003 -
Danish Medical Journal Nov 2016The growing proportion of elderly people represents an increasing economic burden, not least because of age-associated diseases that pose a significant cost to the... (Review)
Review
The growing proportion of elderly people represents an increasing economic burden, not least because of age-associated diseases that pose a significant cost to the health service. Finding possible interventions to age-associated disorders therefore have wide ranging implications. A number of genetically defined accelerated aging diseases have been characterized that can aid in our understanding of aging. Interestingly, all these diseases are associated with defects in the maintenance of our genome. A subset of these disorders, Cockayne syndrome, Xeroderma pigmentosum group A and ataxia-telangiectasia, show neurological involvement reminiscent of what is seen in primary human mitochondrial diseases. Mitochondria are the power plants of the cells converting energy stored in oxygen, sugar, fat, and protein into ATP, the energetic currency of our body. Emerging evidence has linked this organelle to aging and finding mitochondrial dysfunction in accelerated aging disorders thereby strengthens the mitochondrial theory of aging. This theory states that an accumulation of damage to the mitochondria may underlie the process of aging. Indeed, it appears that some accelerated aging disorders that show neurodegeneration also have mitochondrial dysfunction. The mitochondrial alterations may be secondary to defects in nuclear DNA repair. Indeed, nuclear DNA damage may lead to increased energy consumption, alterations in mitochondrial ATP production and defects in mitochondrial recycling, a term called mitophagy. These changes may be caused by activation of poly-ADP-ribose-polymerase 1 (PARP1), an enzyme that responds to DNA damage. Upon activation PARP1 utilizes key metabolites that attenuate pathways that are normally protective for the cell. Notably, pharmacological inhibition of PARP1 or reconstitution of the metabolites rescues the changes caused by PARP1 hyperactivation and in many cases reverse the phenotypes associated with accelerated aging. This implies that modulation of PARP1 or the downstream metabolites may be a therapeutic strategy for treating accelerated aging disorders and potentially age-associated neurological decline seen in the normal population.
Topics: Aging, Premature; Animals; Ataxia Telangiectasia; Bloom Syndrome; Cockayne Syndrome; DNA Repair; Dyskeratosis Congenita; Fanconi Anemia; Humans; Mitochondria; Mitophagy; NAD; Neurodegenerative Diseases; Poly(ADP-ribose) Polymerases; Progeria; Rothmund-Thomson Syndrome; Sirtuin 1; Telomere Shortening; Werner Syndrome; Xeroderma Pigmentosum
PubMed: 27808039
DOI: No ID Found -
Journal of Translational Medicine Jul 2023Prostate cancer (PCa) is a prevalent malignant disease affecting a significant number of males globally. Elevated expression of the Bloom's syndrome protein (BLM)...
BACKGROUND
Prostate cancer (PCa) is a prevalent malignant disease affecting a significant number of males globally. Elevated expression of the Bloom's syndrome protein (BLM) helicase has emerged as a promising cancer biomarker, being associated with the onset and progression of PCa. Nevertheless, the precise molecular mechanisms governing BLM regulation in PCa remain elusive.
METHODS
The expression of BLM in human specimens was analyzed using immnohistochemistry (IHC). A 5'-biotin-labeled DNA probe containing the promoter region of BLM was synthesized to pull down BLM promoter-binding proteins. Functional studies were conducted using a range of assays, including CCK-8, EdU incorporation, clone formation, wound scratch, transwell migration, alkaline comet assay, xenograft mouse model, and H&E staining. Mechanistic studies were carried out using various techniques, including streptavidin-agarose-mediated DNA pull-down, mass spectrometry (MS), immunofluorescence (IF), dual luciferase reporter assay system, RT-qPCR, ChIP-qPCR, co-immunoprecipitation (co-IP), and western blot.
RESULTS
The results revealed significant upregulation of BLM in human PCa tissues, and its overexpression was associated with an unfavorable prognosis in PCa patients. Increased BLM expression showed significant correlations with advanced clinical stage (P = 0.022) and Gleason grade (P = 0.006). In vitro experiments demonstrated that BLM knockdown exerted inhibitory effects on cell proliferation, clone formation, invasion, and migration. Furthermore, PARP1 (poly (ADP-ribose) polymerase 1) was identified as a BLM promoter-binding protein. Further investigations revealed that the downregulation of PARP1 led to increased BLM promoter activity and expression, while the overexpression of PARP1 exerted opposite effects. Through mechanistic studies, we elucidated that the interaction between PARP1 and HSP90AB1 (heat shock protein alpha family class B) enhanced the transcriptional regulation of BLM by counteracting the inhibitory influence of PARP1 on BLM. Furthermore, the combination treatment of olaparib with ML216 demonstrated enhanced inhibitory effects on cell proliferation, clone formation, invasion, and migration. It also induced more severe DNA damage in vitro and exhibited superior inhibitory effects on the proliferation of PC3 xenograft tumors in vivo.
CONCLUSIONS
The results of this study underscore the significance of BLM overexpression as a prognostic biomarker for PCa, while also demonstrating the negative regulatory impact of PARP1 on BLM transcription. The concurrent targeting of BLM and PARP1 emerges as a promising therapeutic approach for PCa treatment, holding potential clinical significance.
Topics: Animals; Humans; Male; Mice; Cell Line, Tumor; Cell Proliferation; Disease Models, Animal; Gene Expression Regulation, Neoplastic; HSP90 Heat-Shock Proteins; Poly (ADP-Ribose) Polymerase-1; Prognosis; Prostatic Neoplasms; Up-Regulation
PubMed: 37415147
DOI: 10.1186/s12967-023-04288-z -
The Journal of Contemporary Dental... Jun 2016Oral squamous cell carcinoma is the most common malignancy of the oral cavity, which is usually preceded by a myriad of oral potentially malignant disorders (OPMDs). In... (Review)
Review
Oral squamous cell carcinoma is the most common malignancy of the oral cavity, which is usually preceded by a myriad of oral potentially malignant disorders (OPMDs). In the classification of OPMDs, inherited cancer syndromes (ICSs) were proposed as one of the categories. Inherited cancer syndromes are genetic disorders in which inherited genetic mutation in one or more genes predispose the affected individuals to the development of cancer and may also cause its early onset. Many of these syndromes are caused by mutations in tumor suppressor genes, oncogenes, and genes involved in angiogenesis. General dental practitioners frequently come across OPMDs in their day-to-day practice. It becomes of paramount importance to have knowledge about these rare but prognostically important OPMDs. With this view in mind, in this article, efforts have been made to comprehensively discuss about various ICSs that have higher potential of transformation into oral cancer. The ICSs discussed in this article are xeroderma pigmentosum (XP), ataxia telangiectasia (AT), Bloom syndrome (BS), Fanconi's anemia (FA), and Li-Fraumeni syndrome (LFS), with special emphasis on signs, symptoms, and genetic considerations.
Topics: Genetic Predisposition to Disease; Humans; Mouth Neoplasms; Neoplastic Syndromes, Hereditary
PubMed: 27484606
DOI: 10.5005/jp-journals-10024-1880 -
BioRxiv : the Preprint Server For... Jan 2023Bloom syndrome helicase (BLM) is a RecQ-family helicase implicated in a variety of cellular processes, including DNA replication, DNA repair, and telomere maintenance....
Bloom syndrome helicase (BLM) is a RecQ-family helicase implicated in a variety of cellular processes, including DNA replication, DNA repair, and telomere maintenance. Mutations in human cause Bloom syndrome (BS), an autosomal recessive disorder that leads to myriad negative health impacts including a predisposition to cancer. BS-causing mutations in often negatively impact BLM ATPase and helicase activity. While mutations that cause BS have been well characterized both and , there are other less studied mutations that exist in the human population that do not lead to BS. Two of these non-BS mutations, encoding BLM P868L and BLM G1120R, when homozygous, increase sister chromatid exchanges in human cells. To characterize these naturally occurring BLM mutant proteins , we purified the BLM catalytic core (BLM , residues 636-1298) with either the P868L or G1120R substitution. We also purified a BLM K869A K870A mutant protein, which alters a lysine-rich loop proximal to the P868 residue. We found that BLM P868L and G1120R proteins were both able to hydrolyze ATP, bind diverse DNA substrates, and unwind G-quadruplex and duplex DNA structures. Molecular dynamics simulations suggest that the P868L substitution weakens the DNA interaction with the winged-helix domain of BLM and alters the orientation of one lobe of the ATPase domain. Because BLM P868L and G1120R retain helicase function , it is likely that the increased genome instability is caused by specific impacts of the mutant proteins . Interestingly, we found that BLM K869A K870A has diminished ATPase activity, weakened binding to duplex DNA structures, and less robust helicase activity compared to wild-type BLM . Thus, the lysine-rich loop may have an important role in ATPase activity and specific binding and DNA unwinding functions in BLM.
PubMed: 36747637
DOI: 10.1101/2023.01.26.525669 -
Cytogenetic and Genome Research 2021Human RecQ helicases play diverse roles in the maintenance of genomic stability. Inactivating mutations in 3 of the 5 human RecQ helicases are responsible for the... (Review)
Review
Human RecQ helicases play diverse roles in the maintenance of genomic stability. Inactivating mutations in 3 of the 5 human RecQ helicases are responsible for the pathogenesis of Werner syndrome (WS), Bloom syndrome (BS), Rothmund-Thomson syndrome (RTS), RAPADILINO, and Baller-Gerold syndrome (BGS). WS, BS, and RTS patients are at increased risk for developing many age-associated diseases including cancer. Mutations in RecQL1 and RecQL5 have not yet been associated with any human diseases so far. In terms of disease outcome, RecQL4 deserves special attention because mutations in RecQL4 result in 3 autosomal recessive syndromes (RTS type II, RAPADILINO, and BGS). RecQL4, like other human RecQ helicases, has been demonstrated to play a crucial role in the maintenance of genomic stability through participation in diverse DNA metabolic activities. Increased incidence of osteosarcoma in RecQL4-mutated RTS patients and elevated expression of RecQL4 in sporadic cancers including osteosarcoma suggest that loss or gain of RecQL4 expression is linked with cancer susceptibility. In this review, current and future perspectives are discussed on the potential use of RecQL4 as a novel cancer therapeutic target.
Topics: Bloom Syndrome; Genetic Predisposition to Disease; Humans; Molecular Targeted Therapy; Mutation; Neoplasms; RecQ Helicases; Risk Factors; Rothmund-Thomson Syndrome; Werner Syndrome
PubMed: 34474412
DOI: 10.1159/000516568 -
American Journal of Hematology Nov 2021Germline predisposition syndromes (GPS) result from constitutional aberrations in tumor suppressive and homeostatic genes, increasing risk for neoplasia in affected...
Germline predisposition syndromes (GPS) result from constitutional aberrations in tumor suppressive and homeostatic genes, increasing risk for neoplasia in affected kindred. In this study, we present clinical and genomic data on 144 Mayo Clinic patients with GPS; 59 evaluated prospectively using an algorithm-based diagnostic approach in the setting of a dedicated GPS/ inherited bone marrow failure syndrome (IBMFS) clinic. Seventy-two (50%) patients had IBMFS (telomere biology disorders-32,Fanconi anemia-18, Diamond Blackfan Anemia - 11, congenital neutropenia-5, Schwachman-Diamond Syndrome-5 and Bloom Syndrome-1), 27 (19%) had GPS with antecedent thrombocytopenia (RUNX1-FPD-15, ANKRD26-6, ETV6-2, GATA1-1, MPL-3), 28 (19%) had GPS without antecedent thrombocytopenia (GATA2 haploinsufficiency-16, DDX41-10, CBL-1 and CEBPA-1) and 17 (12%) had general cancer predisposition syndromes (ataxia telangiectasia-7, heterozygous ATM variants-3, CHEK2-2, TP53-2, CDK2NA-1, NF1-1 and Nijmegen Breakage Syndrome-1). Homozygous and heterozygous ATM pathogenic variants were exclusively associated with lymphoproliferative disorders (LPD), while DDX41 GPS was associated with LPD and myeloid neoplasms. The use of somatic NGS-testing identified clonal evolution in GPS patients, with ASXL1, RAS pathway genes, SRSF2 and TET2 being most frequently mutated. Fifty-two (91%) of 59 prospectively identified GPS patients had a change in their management approach, including additional GPS-related screening in 42 (71%), referral for allogenic HSCT workup and screening of related donors in 16 (27%), medication initiation and selection of specific conditioning regimens in 14 (24%), and genetic counseling with specific intent of fertility preservation and preconceptual counseling in 10 (17%) patients; highlighting the importance of dedicated GPS screening, detection and management programs for patients with hematological neoplasms.
Topics: Adolescent; Adult; Aged; Anemia, Diamond-Blackfan; Child; Child, Preschool; Clonal Evolution; Congenital Bone Marrow Failure Syndromes; Fanconi Anemia; Female; Genetic Predisposition to Disease; Germ-Line Mutation; Hematologic Neoplasms; Humans; Infant; Male; Middle Aged; Young Adult
PubMed: 34390506
DOI: 10.1002/ajh.26321 -
Current Opinion in Endocrinology,... Feb 2016Pandemic obesity is the most pressing health issue of this century. The most successful treatment so far is bariatric surgery, but for various reasons, surgery cannot be... (Review)
Review
PURPOSE OF REVIEW
Pandemic obesity is the most pressing health issue of this century. The most successful treatment so far is bariatric surgery, but for various reasons, surgery cannot be applied to all patients who require treatment. Gastrointestinal hormones are likely to play a key role in the success of bariatric surgery. This article examines in detail three of these gut hormones: peptide YY, oxyntomodulin and pancreatic polypeptide, and reviews how recent developments may offer new targets for therapy.
RECENT FINDINGS
Both the free fatty acid 2 and the melanocortin 4 receptors have been discovered to regulate peptide YY and glucagon-like peptide-1 secretion, and drugs targeting these may represent new antiobesity therapies. Dual agonism of glucagon-like peptide-1 and glucagon receptors, for example with oxyntomodulin, has synergistic effects in reducing appetite and increasing energy expenditure. Plasma pancreatic polypeptide concentration correlates with visceral adiposity, and may serve as a biomarker for metabolic syndrome.
SUMMARY
Gut hormones continue to show promise on an individual basis as anti-obesity treatments, but combination therapies are needed to achieve beneficial effects comparable to bariatric surgery. Innovative pathways for stimulating native gut hormone secretion may well provide an alternative method for weight loss without necessitating the administration of gut hormone analogues via injection.
Topics: Biomarkers; Humans; Obesity; Oxyntomodulin; Pancreatic Polypeptide; Peptide YY
PubMed: 26702847
DOI: 10.1097/MED.0000000000000216