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Oxidative Medicine and Cellular... 2019Prostate cancer (PC) is a common malignant tumor and a leading cause of cancer-related death in men worldwide. In order to design new therapeutic interventions for PC,...
PURPOSE
Prostate cancer (PC) is a common malignant tumor and a leading cause of cancer-related death in men worldwide. In order to design new therapeutic interventions for PC, an understanding of the molecular events underlying PC tumorigenesis is required. Bloom syndrome protein (BLM) is a RecQ-like helicase, which helps maintain genetic stability. BLM dysfunction has been implicated in tumor development, most recently during PC tumorigenesis. However, the molecular basis for BLM-induced PC progression remains poorly characterized. In this study, we investigated whether BLM modulates the phosphorylation of an array of prooncogenic signaling pathways to promote PC progression.
METHODS
We analyzed differentially expressed proteins (DEPs) using iTRAQ technology. Site-directed knockout of BLM in PC-3 prostate cancer cells was performed using CRISPR/Cas9-mediated homologous recombination gene editing to confirm the effects of BLM on DEPs. PathScan® Antibody Array Kits were used to analyze the phosphorylation of nodal proteins in PC tissue. Immunohistochemistry and automated western blot (WES) analyses were used to validate these findings.
RESULTS
We found that silencing BLM in PC-3 cells significantly reduced their proliferative capacity. In addition, BLM downregulation significantly reduced levels of phosphorylated protein kinase B (AKT (Ser473)) and proline-rich AKT substrate of 40 kDa (PRAS40 (Thr246)), and this was accompanied by enhanced ROS (reactive oxygen species) levels. In addition, we found that AKT and PRAS40 inhibition reduced BLM, increased ROS levels, and induced PC cell apoptosis.
CONCLUSIONS
We demonstrated that BLM activates AKT and PRAS40 to promote PC cell proliferation and survival. We further propose that ROS act in concert with BLM to facilitate PC oncogenesis, potentially via further enhancing AKT signaling and downregulating PTEN expression. Importantly, inhibiting the BLM-AKT-PRAS40 axis induced PC cell apoptosis. Thus, we highlight new avenues for novel anti-PC treatments.
Topics: Adaptor Proteins, Signal Transducing; Cell Proliferation; Cell Survival; Gene Expression Regulation, Neoplastic; Humans; Male; PC-3 Cells; Prostatic Neoplasms; Proto-Oncogene Proteins c-akt; Reactive Oxygen Species; RecQ Helicases
PubMed: 31210839
DOI: 10.1155/2019/3685817 -
Current Biology : CB Jan 2017In most sexually reproducing organisms, crossover formation between homologous chromosomes is necessary for proper chromosome disjunction during meiosis I. During...
In most sexually reproducing organisms, crossover formation between homologous chromosomes is necessary for proper chromosome disjunction during meiosis I. During meiotic recombination, a subset of programmed DNA double-strand breaks (DSBs) are repaired as crossovers, with the remainder becoming noncrossovers [1]. Whether a repair intermediate is designated to become a crossover is a highly regulated decision that integrates several crossover patterning processes, both along chromosome arms (interference and the centromere effect) and between chromosomes (crossover assurance) [2]. Because the mechanisms that generate crossover patterning have remained elusive for over a century, it has been difficult to assess the relationship between crossover patterning and meiotic chromosome behavior. We show here that meiotic crossover patterning is lost in Drosophila melanogaster mutants that lack the Bloom syndrome helicase. In the absence of interference and the centromere effect, crossovers are distributed more uniformly along chromosomes. Crossovers even occur on the small chromosome 4, which normally never has meiotic crossovers [3]. Regulated distribution of crossovers between chromosome pairs is also lost, resulting in an elevated frequency of homologs that do not receive a crossover, which in turn leads to elevated nondisjunction.
Topics: Animals; DNA Helicases; Drosophila Proteins; Drosophila melanogaster; Female; Homologous Recombination; Male; Meiosis; Nondisjunction, Genetic
PubMed: 27989672
DOI: 10.1016/j.cub.2016.10.055 -
Frontiers in Immunology 2021Type I interferons (IFNs) as part of the innate immune system have an outstanding importance as antiviral defense cytokines that stimulate innate and adaptive immune... (Review)
Review
Type I interferons (IFNs) as part of the innate immune system have an outstanding importance as antiviral defense cytokines that stimulate innate and adaptive immune responses. Upon sensing of pattern recognition particles (PRPs) such as nucleic acids, IFN secretion is activated and induces the expression of interferon stimulated genes (ISGs). Uncontrolled constitutive activation of the type I IFN system can lead to autoinflammation and autoimmunity, which is observed in autoimmune disorders such as systemic lupus erythematodes and in monogenic interferonopathies. They are caused by mutations in genes which are involved in sensing or metabolism of intracellular nucleic acids and DNA repair. Many authors described mechanisms of type I IFN secretion upon increased DNA damage, including the formation of micronuclei, cytosolic chromatin fragments and destabilization of DNA binding proteins. Hereditary cutaneous DNA damage syndromes, which are caused by mutations in proteins of the DNA repair, share laboratory and clinical features also seen in autoimmune disorders and interferonopathies; hence a potential role of DNA-damage-induced type I IFN secretion seems likely. Here, we aim to summarize possible mechanisms of IFN induction in cutaneous DNA damage syndromes with defects in the DNA double-strand repair and nucleotide excision repair. We review recent publications referring to Ataxia teleangiectasia, Bloom syndrome, Rothmund-Thomson syndrome, Werner syndrome, Huriez syndrome, and Xeroderma pigmentosum. Furthermore, we aim to discuss the role of type I IFN in cancer and these syndromes.
Topics: Animals; Autoimmune Diseases; Biomarkers; Cellular Senescence; DNA Breaks, Double-Stranded; DNA Damage; DNA Repair; Diagnosis, Differential; Disease Management; Disease Susceptibility; Humans; Interferon Type I; Neoplasms; Skin; Syndrome
PubMed: 34381458
DOI: 10.3389/fimmu.2021.715723 -
Genome Integrity Nov 2010Bloom Syndrome (BS) is an autosomal recessive disorder due to mutation in Bloom helicase (referred in literature either as BLM helicase or BLM). Patients with BS are...
Bloom Syndrome (BS) is an autosomal recessive disorder due to mutation in Bloom helicase (referred in literature either as BLM helicase or BLM). Patients with BS are predisposed to almost all forms of cancer. BS patients are even today diagnosed in the clinics by hyper-recombination phenotype that is manifested by high rates of Sister Chromatid Exchange. The function of BLM as a helicase and its role during the regulation of homologous recombination (HR) is well characterized. However in the last few years the role of BLM as a DNA damage sensor has been revealed. For example, it has been demonstrated that BLM can stimulate the ATPase and chromatin remodeling activities of RAD54 in vitro. This indicates that BLM may increase the accessibility of the sensor proteins that recognize the lesion. Over the years evidence has accumulated that BLM is one of the earliest proteins that accumulates at the site of the lesion. Finally BLM also acts like a "molecular node" by integrating the upstream signals and acting as a bridge between the transducer and effector proteins (which again includes BLM itself), which in turn repair the DNA damage. Hence BLM seems to be a protein involved in multiple functions - all of which may together contribute to its reported role as a "caretaker tumor suppressor". In this review the recent literature documenting the upstream BLM functions has been elucidated and future directions indicated.
PubMed: 21050475
DOI: 10.1186/2041-9414-1-14 -
The Oncologist 2012Genetic syndromes with dermatologic findings and multisystemic involvement (e.g., visceral cancer predisposition) are underrecognized. Patients may have incomplete... (Review)
Review
Genetic syndromes with dermatologic findings and multisystemic involvement (e.g., visceral cancer predisposition) are underrecognized. Patients may have incomplete penetrance and variable expressivity; some patients may solely exhibit subtle skin signs, which create a diagnostic challenge for physicians. Interdisciplinary diagnostic knowledge is required for the early diagnosis and monitoring of patients with these syndromes. Cutaneous changes in the face-one of the most highly exposed areas-can be easily noticed by patients themselves, their families and friends, and physicians; these changes may serve as early indicators of genetic syndromes with malignancies. In this article, we present examples of genetic syndromes with malignancies for which a thorough faciocutaneous examination is helpful in establishing a diagnosis. These examples include lentiginosis-related syndromes (e.g., Peutz-Jeghers syndrome, Carney complex), photosensitivity-related syndromes (Bloom syndrome, Rothmund-Thomson syndrome), and hamartoma-related syndromes (Cowden syndrome, multiple endocrine neoplasia syndrome, tuberous sclerosis complex, Gardner syndrome, Muir-Torre syndrome). The characteristics of these faciocutaneous clues are summarized and discussed. Objective evaluation of these faciocutaneous clues in combination with other clinical information (e.g., family history, histopathological findings, combination with other concomitant faciocutaneous lesions) is emphasized to narrow the diagnosis. The list of genetic syndromes with faciocutaneous manifestations is still expanding. Increased awareness of faciocutaneous markers can alert physicians to underlying syndromes and malignancies, render earlier screening and detection of associated medical issues, and allow for genetic counseling of family members.
Topics: Adolescent; Costello Syndrome; Diagnosis, Differential; Humans; Male; Neoplastic Syndromes, Hereditary; Skin Diseases
PubMed: 22707513
DOI: 10.1634/theoncologist.2012-0033 -
PloS One 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 BLM cause Bloom syndrome (BS), an autosomal recessive disorder that leads to myriad negative health impacts including a predisposition to cancer. BS-causing mutations in BLM often negatively impact BLM ATPase and helicase activity. While BLM mutations that cause BS have been well characterized both in vitro and in vivo, there are other less studied BLM 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 in vitro, we purified the BLM catalytic core (BLMcore, residues 636-1298) with either the P868L or G1120R substitution. We also purified a BLMcore K869A K870A mutant protein, which alters a lysine-rich loop proximal to the P868 residue. We found that BLMcore 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 BLMcore P868L and G1120R retain helicase function in vitro, it is likely that the increased genome instability is caused by specific impacts of the mutant proteins in vivo. Interestingly, we found that BLMcore K869A K870A has diminished ATPase activity, weakened binding to duplex DNA structures, and less robust helicase activity compared to wild-type BLMcore. Thus, the lysine-rich loop may have an important role in ATPase activity and specific binding and DNA unwinding functions in BLM.
Topics: Humans; Bloom Syndrome; Lysine; RecQ Helicases; DNA; Mutant Proteins
PubMed: 37267408
DOI: 10.1371/journal.pone.0281524 -
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 -
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 -
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 -
Genomics, Proteomics & Bioinformatics Jun 2016DNA double-strand breaks (DSBs), which arise following exposure to a number of endogenous and exogenous agents, can be repaired by either the homologous recombination... (Review)
Review
DNA double-strand breaks (DSBs), which arise following exposure to a number of endogenous and exogenous agents, can be repaired by either the homologous recombination (HR) or non-homologous end-joining (NHEJ) pathways in eukaryotic cells. A vital step in HR repair is DNA end resection, which generates a long 3' single-stranded DNA (ssDNA) tail that can invade the homologous DNA strand. The generation of 3' ssDNA is not only essential for HR repair, but also promotes activation of the ataxia telangiectasia and Rad3-related protein (ATR). Multiple factors, including the MRN/X complex, C-terminal-binding protein interacting protein (CtIP)/Sae2, exonuclease 1 (EXO1), Bloom syndrome protein (BLM)/Sgs1, DNA2 nuclease/helicase, and several chromatin remodelers, cooperate to complete the process of end resection. Here we review the basic machinery involved in DNA end resection in eukaryotic cells.
Topics: Chromatin Assembly and Disassembly; DNA; DNA Breaks, Double-Stranded; DNA Repair; Exodeoxyribonucleases; Genomic Instability; Homologous Recombination; Humans; RecQ Helicases
PubMed: 27240470
DOI: 10.1016/j.gpb.2016.05.002