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Al-Karmalawy AA, Mousa MHA, Sharaky M, Mourad MAE, El-Dessouki AM, Hamouda AO, Alnajjar R, Ayed AA, Shaldam MA, Tawfik HO. Lead Optimization of BIBR1591 To Improve Its Telomerase Inhibitory Activity: Design and Synthesis of Novel Four Chemical Series with In Silico, In Vitro, and In Vivo Preclinical Assessments. J Med Chem 2024; 67:492-512. [PMID: 38117230 DOI: 10.1021/acs.jmedchem.3c01708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2023]
Abstract
Herein, modifications to the previously reported BIBR1591 were conducted to obtain bioisosteric candidates with improved activities. The % inhibition of the newly afforded candidates against the telomerase target was investigated. Notably, 6f achieved superior telomerase inhibition (63.14%) compared to BIBR1532 and BIBR1591 (69.64 and 51.58%, respectively). In addition, 8a and 8b showed comparable promising telomerase inhibition with 58.65 and 55.57%, respectively, which were recorded to be frontier to that of BIBR1591. 6f, 8a, and 8b were tested against five cancer cell lines related to the lung and liver subtypes. Moreover, 6f was examined on both cell cycle progression and apoptosis induction in HuH7 cancer cells. Furthermore, the in vivo antitumor activity of 6f was further assessed in female mice with solid Ehrlich carcinoma. In addition, molecular docking and molecular dynamics simulations were carried out. Collectively, 6f, 8a, and 8b could be considered potential new telomerase inhibitors to be subjected to further investigation and/or optimization.
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Affiliation(s)
- Ahmed A Al-Karmalawy
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Horus University-Egypt, New Damietta 34518, Egypt
- Pharmaceutical Chemistry Department, Faculty of Pharmacy, Ahram Canadian University, 6h of October City, Giza 12566, Egypt
| | - Mai H A Mousa
- Pharmaceutical Chemistry Department, Faculty of Pharmacy and Drug Technology, Egyptian Chinese University, Cairo 11786, Egypt
| | - Marwa Sharaky
- Cancer Biology Department, Pharmacology Unit, National Cancer Institute (NCI), Cairo University, Cairo 12613, Egypt
| | - Mai A E Mourad
- Medicinal Chemistry Department, Faculty of Pharmacy, Port-Said University, Port-Said 42511, Egypt
| | - Ahmed M El-Dessouki
- Pharmacology and Toxicology Department, Faculty of Pharmacy, Ahram Canadian University, 6th of October City, Giza 12566, Egypt
| | - Amir O Hamouda
- Department of Biochemistry, Faculty of Pharmacy, Horus University-Egypt, New Damietta 34518, Egypt
| | - Radwan Alnajjar
- Department of Chemistry, Faculty of Science, University of Benghazi, Benghazi 1308, Libya
- PharmD, Faculty of Pharmacy, Libyan International Medical University, Benghazi 1308, Libya
| | - Abdelmoneim A Ayed
- Department of Chemistry, Faculty of Science, Tanta University, Tanta 31527, Egypt
| | - Moataz A Shaldam
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Kafrelsheikh University, Kafrelsheikh 33516, Egypt
| | - Haytham O Tawfik
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Tanta University, Tanta 31527, Egypt
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Bukic E, Milasin J, Toljic B, Jadzic J, Jevtovic D, Obradovic B, Dragovic G. Association between Combination Antiretroviral Therapy and Telomere Length in People Living with Human Immunodeficiency Virus. BIOLOGY 2023; 12:1210. [PMID: 37759609 PMCID: PMC10525818 DOI: 10.3390/biology12091210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/03/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023]
Abstract
Long-term exposure to combination antiretroviral therapy (cART) may be associated with accelerated ageing. Telomere length is considered to be reliable aging biomarker. The aim of this study was to compare patients' relative telomere length (RTL) between and within different cART classes and to estimate the impact of certain HIV-related variables on RTL. The study was conducted in 176 HIV-infected male patients receiving cART, with ≤50 copies HIV RNA/mL plasma. RTL was determined from mononuclear cells by quantitative polymerase chain reaction. Standard statistical tests and unsupervised machine learning were performed. The mean RTL was 2.50 ± 1.87. There was no difference (p = 0.761) in RTL between therapeutic groups: two nucleoside reverse transcriptase inhibitors as the backbone treatment, combined with either integrase inhibitor, protease inhibitor, or non-nucleoside reverse transcriptase inhibitor (NNRTI). Machine learning results suggested duration of HIV infection, CD4+ T-cell count, and cART, including NNRTI, as potentially significant variables impacting RTL. Kendall's correlation test excluded duration of HIV infection (p = 0.220) and CD4+ T-cell count (p = 0.536) as significant. The Mann-Whitney test confirmed that cART containing NNRTI impacted RTL (p = 0.018). This was the first study to show that patients using efavirenz within cART had significantly shorter telomeres than patients using nevirapine.
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Affiliation(s)
- Ena Bukic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, University of Belgrade Faculty of Medicine, 11000 Belgrade, Serbia
| | - Jelena Milasin
- Department of Human Genetics, School of Dental Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Bosko Toljic
- Department of Human Genetics, School of Dental Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Jelena Jadzic
- Center of Bone Biology, University of Belgrade Faculty of Medicine, 11000 Belgrade, Serbia
| | - Djordje Jevtovic
- Infective and Tropical Diseases Hospital, University of Belgrade Faculty of Medicine, 11000 Belgrade, Serbia
| | - Bozana Obradovic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, University of Belgrade Faculty of Medicine, 11000 Belgrade, Serbia
| | - Gordana Dragovic
- Department of Pharmacology, Clinical Pharmacology and Toxicology, University of Belgrade Faculty of Medicine, 11000 Belgrade, Serbia
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Teng Y, Huang DQ, Li RX, Yi C, Zhan YQ. Association Between Telomere Length and Risk of Lung Cancer in an Asian Population: A Mendelian Randomization Study. World J Oncol 2023; 14:277-284. [PMID: 37560336 PMCID: PMC10409562 DOI: 10.14740/wjon1624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 07/19/2023] [Indexed: 08/11/2023] Open
Abstract
BACKGROUND Several traditional observational studies and Mendelian randomization (MR) studies have indicated an association between leukocyte telomere length (LTL) and the risk of lung cancer in the European population. However, the results in the Asian population are still unclear. The objective was to reveal the genetic causal association between LTL and the risk of lung cancer in the Asian population. METHODS We conducted a two-sample MR analysis using summary statistics. Instrumental variables (IVs) were obtained from the genome-wide association studies (GWAS) of LTL (n = 23,096) and lung cancer (n = 212,453) of Asian ancestry. We applied the random-effects inverse-variance weighted (IVW) model as the main method. As well, several other models were performed as complementary methods to assess the impact of potential MR assumption violations, including MR-Egger regression, weighted median, and weighted mode models. RESULTS We included eight single-nucleotide polymorphisms (SNPs) as IVs for LTL and found that LTL was significantly associated with the risk of lung cancer in the IVW model (odds ratio (OR): 1.60; 95% confidence interval (CI): 1.31 - 1.97; P = 5.96 × 10-6), which was in line with the results in the weighted median and weighted mode models. However, the relationship was not statistically significant in the MR-Egger regression model (OR: 1.44; 95% CI: 0.92 - 2.26; P = 0.160). Sensitivity analyses indicated the robustness of the results. CONCLUSIONS This two-sample MR study confirmed that longer telomere length significantly increased the risk of lung cancer in the Asian population, which was in accord with findings in the Western population.
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Affiliation(s)
- Yi Teng
- Department of Epidemiology, School of Public Health (Shenzhen), Sun Yat-Sen University, Shenzhen, China
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- These authors contributed equally to this work
| | - Dan Qi Huang
- Department of Epidemiology, School of Public Health (Shenzhen), Sun Yat-Sen University, Shenzhen, China
- National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- These authors contributed equally to this work
| | - Rui Xi Li
- Department of Hepatobiliary and Pancreatic Surgery, The Eighth Affiliated Hospital, Sun Yat-Sen University, China
- These authors contributed equally to this work
| | - Chao Yi
- Guangming Center for Disease Control and Prevention, Shenzhen, China
| | - Yi Qiang Zhan
- Department of Epidemiology, School of Public Health (Shenzhen), Sun Yat-Sen University, Shenzhen, China
- Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden
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Lin F, Huang J, Zhu W, Jiang T, Guo J, Xia W, Chen M, Guo L, Deng W, Lin H. Prognostic value and immune landscapes of TERT promoter methylation in triple negative breast cancer. Front Immunol 2023; 14:1218987. [PMID: 37575241 PMCID: PMC10416624 DOI: 10.3389/fimmu.2023.1218987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 07/14/2023] [Indexed: 08/15/2023] Open
Abstract
Background Treatment options for patients with triple-negative breast cancer (TNBC) remain limited to mainstay therapies owing to a lack of efficacious therapeutic targets. Accordingly, there is an urgent need to discover and identify novel molecular targets for the treatment and diagnosis of this disease. In this study, we analyzed the correlation of telomerase reverse transcriptase (TERT) methylation status with TERT expression, prognosis, and immune infiltration in TNBC and identified the role of TERT methylation in the regulation TNBC prognosis and immunotherapy. Methods Data relating to the transcriptome, clinicopathological characteristics and methylation of TNBC patients were obtained from The Cancer Genome Atlas (TCGA) database. TERT expression levels and differential methylation sites (DMSs) were detected. The correlations between TERT expression and DMSs were calculated. Kaplan-Meier curves was plotted to analyze the relationship between the survival of TNBC patients and the DMSs. The correlations of DMSs and TERT expression with several immunological characteristics of immune microenvironment (immune cell infiltration, immunomodulators, immune-related biological pathways, and immune checkpoints) were assessed. The results were validated using 40 TNBC patients from Sun Yat-sen University Cancer Center (SYSUCC). Results Six DMSs were identified. Among them, four sites (cg11625005, cg07380026, cg17166338, and cg26006951) were within the TERT promoter, in which two sites (cg07380026 and cg26006951) were significantly related to the prognosis of patients with TNBC. Further validation using 40 TNBC samples from SYSUCC showed that the high methylation of the cg26006951 CpG site was associated with poor survival prognosis (P=0.0022). TERT expression was significantly correlated with pathological N stage and clinical stage, and cg07380026 were significantly associated with pathological T and N stages in the TCGA cohort. Moreover, the methylation site cg26006951, cg07380026 and TERT expression were significantly correlated with immune cell infiltration, common immunomodulators, and the level of the immune checkpoint receptor lymphocyte activation gene 3 (LAG-3) in TNBC patients. Conclusion TERT promotertypermethylation plays an important role in TERT expression regulation and tumor microenvironment in TNBC. It is associated with overall survival and LAG-3 expression. TERT promoter hypermethylation may be a potential molecular biomarker for predicting response to the TERT inhibitors and immune checkpoint inhibitors in TNBC.
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Affiliation(s)
| | | | | | | | | | | | | | - Ling Guo
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Wuguo Deng
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Huanxin Lin
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, China
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D'Aronco G, Ferraro P, Sassano V, Dagostino C, Biancotto M, Palumbo E, Presot E, Russo A, Bianchi V, Rampazzo C. SAMHD1 restricts the deoxyguanosine triphosphate pool contributing to telomere stability in telomerase-positive cells. FASEB J 2023; 37:e22883. [PMID: 36934410 DOI: 10.1096/fj.202300122r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/26/2023] [Accepted: 03/07/2023] [Indexed: 03/20/2023]
Abstract
SAMHD1 (Sterile alpha motif and histidine/aspartic acid domain-containing protein 1) is a dNTP triphosphohydrolase crucial in the maintenance of balanced cellular dNTP pools, which support genome integrity. In SAMHD1 deficient fibroblasts isolated from Aicardi-Goutières Syndrome (AGS) patients, all four DNA precursors are increased and markedly imbalanced with the largest effect on dGTP, a key player in the modulation of telomerase processivity. Here, we present data showing that SAMHD1, by restricting the dGTP pool, contributes to telomere maintenance in hTERT-immortalized human fibroblasts from AGS patients as well as in telomerase positive cancer cell lines. Only in cells expressing telomerase, the lack of SAMHD1 causes excessive lengthening of telomeres and telomere fragility, whereas primary fibroblasts lacking both SAMHD1 and telomerase enter normally into senescence. Telomere lengthening observed in SAMHD1 deficient but telomerase proficient cells is a gradual process, in accordance with the intrinsic property of telomerase of adding only a few tens of nucleotides for each cycle. Therefore, only a prolonged exposure to high dGTP content causes telomere over-elongation. hTERT-immortalized AGS fibroblasts display also high fragility of chromosome ends, a marker of telomere replication stress. These results not only demonstrate the functional importance of dGTP cellular level but also reveal the critical role played by SAMHD1 in restraining telomerase processivity and safeguarding telomere stability.
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Affiliation(s)
| | - Paola Ferraro
- Department of Biology, University of Padova, Padova, Italy
| | | | | | | | - Elisa Palumbo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Ettore Presot
- Department of Biology, University of Padova, Padova, Italy
| | - Antonella Russo
- Department of Molecular Medicine, University of Padova, Padova, Italy
| | - Vera Bianchi
- Department of Biology, University of Padova, Padova, Italy
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Noguera JC, Velando A. Maternal testosterone affects offspring telomerase activity in a long-lived seabird. Ecol Evol 2022; 12:e9281. [PMID: 36110870 PMCID: PMC9465397 DOI: 10.1002/ece3.9281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 07/29/2022] [Accepted: 08/19/2022] [Indexed: 11/10/2022] Open
Abstract
Androgens are a group of steroid hormones that have long been proposed as a mechanism underpinning intergenerational plasticity. In birds, maternally allocated egg testosterone, one of the main androgens in vertebrates, affects a wide variety of offspring phenotypic traits but the mechanisms underlying this form of intergenerational plasticity are not yet well understood. Recent in vitro and animal model studies have shown that telomerase expression and activity are important targets of androgen signaling. The telomerase enzyme is known for its repair function on telomeres, the DNA-protein complexes at the ends of chromosomes that are involved in genomic integrity and cell aging. However, the role of maternal testosterone in influencing offspring telomerase levels in natural populations and its consequences on telomere length and potentially on offspring development is still unknown. Here, by experimentally modifying the level of egg testosterone in a natural population of yellow-legged gull (Larus michahellis), we show that chicks hatched from testosterone-treated eggs had higher average levels of telomerase and faster growth than controls during the first week of life. While testosterone-treated chicks also tended to have longer telomeres than controls at hatching this difference disappeared by day 6 of age. Overall, our results suggest that maternal testosterone may have a potential adaptive value by promoting offspring growth and presumably telomerase levels, as this enzyme plays other important physiological functions (e.g., stress resistance, cell signaling, or tissue genesis) besides telomere lengthening. Nonetheless, our knowledge of the potential adaptive function of telomerase in natural populations is scarce and so the potential pathways linking maternal hormones, offspring telomerase, and fitness should be further investigated.
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Affiliation(s)
- Jose C Noguera
- Grupo de Ecología Animal (GEA), Centro de Investigación Marina (CIM) Universidad de Vigo Vigo Spain
| | - Alberto Velando
- Grupo de Ecología Animal (GEA), Centro de Investigación Marina (CIM) Universidad de Vigo Vigo Spain
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Association of Relative Telomere Length and Risk of High Human Papillomavirus Load in Cervical Epithelial Cells. Balkan J Med Genet 2022; 24:65-70. [PMID: 36249518 PMCID: PMC9524175 DOI: 10.2478/bjmg-2021-0026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/09/2022] Open
Abstract
Importunate high-risk HPV (HR-HPV) infection is the most common trigger for the cervical carcinogenesis process. In this respect, the presence of cancer can be imputed to telomere lengthening or shortening. This paper explores the possible correlation between relative telomere length and viral load in two groups of women, namely: those with high-risk HPV infection and those who do not have this infection. Thus, samples comprising of 50 women in each group were evaluated for this research. The Amplisens HPV HCR screen-titre-FRT PCR kite was employed for quantitative analysis. Relative telomere length was quantified by real-time PCR. In each of the two HPV load groups, there was no correlation between age and telomere length. Telomere shortening was found in the cervical cell samples of women with high HPV loads, compared with women in the control group. Telomere shortening is associated with elevated HPV loads.
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Impact of superovulation and in vitro fertilization on LINE-1 copy number and telomere length in C57BL/6 J mice blastocysts. Mol Biol Rep 2022; 49:4909-4917. [PMID: 35316424 DOI: 10.1007/s11033-022-07351-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 03/09/2022] [Indexed: 12/09/2022]
Abstract
OBJECTIVE Millions of babies have been conceived by IVF, yet debate about its safety to offspring continues. We hypothesized that superovulation and in vitro fertilization (IVF) promote genomic changes, including altered telomere length (TL) and activation of the retrotransposon LINE-1 (L1), and tested this hypothesis in a mouse model. MATERIAL AND METHODS Experimental study analyzing TL and L1 copy number in C57BL/6 J mouse blastocysts in vivo produced from natural mating cycles (N), in vivo produced following superovulation (S), or in vitro produced following superovulation (IVF). We also examined the effects of prolonged culture on TL and L1 copy number in the IVF group comparing blastocysts cultured 96 h versus blastocysts cultured 120 h. TL and L1 copy number were measured by Real Time PCR. RESULTS TL in S (n = 77; Mean: 1.50 ± 1.15; p = 0.0007) and IVF (n = 82; Mean: 1.72 ± 1.44; p < 0.0001) exceeded that in N (n = 16; Mean: 0.61 ± 0.27). TL of blastocysts cultured 120 h (n = 15, Mean: 2.14 ± 1.05) was significantly longer than that of embryos cultured for 96 h (n = 67, Mean: 1.63 ± 1.50; p = 0.0414). L1 copy number of blastocysts cultured for 120 h (n = 15, Mean: 1.71 ± 1.49) exceeded that of embryos cultured for 96 h (n = 67, Mean: 0.95 ± 1.03; p = 0.0162). CONCLUSIONS Intriguingly ovarian stimulation, alone or followed by IVF, produced embryos with significantly longer telomeres compared to in vivo, natural cycle-produced embryos. The significance of this enriched telomere endowment for the health and longevity of offspring born from IVF merit future studies.
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Single-Run Catalysis and Kinetic Control of Human Telomerase Holoenzyme. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1371:109-129. [PMID: 34962637 DOI: 10.1007/5584_2021_676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Genome stability in eukaryotic cells relies on proper maintenance of telomeres at the termini of linear chromosomes. Human telomerase holoenzyme is required for maintaining telomere stability in a majority of proliferative human cells, making it essential for control of cell division and aging, stem cell maintenance, and development and survival of tumor or cancer. A dividing human cell usually contains a limited number of active telomerase holoenzymes. Recently, we discovered that a human telomerase catalytic site undergoes catalysis-dependent shut-off and an inactive site can be reactivated by cellular fractions containing human intracellular telomerase-activating factors (hiTAFs). Such ON-OFF control of human telomerase activity suggests a dynamic switch between inactive and active pools of the holoenzymes. In this review, we will link the ON-OFF control to the thermodynamic and kinetic properties of human telomerase holoenzymes, and discuss its potential contributions to the maintenance of telomere length equilibrium. This treatment suggests probabilistic fluctuations in the number of active telomerase holoenzymes as well as the number of telomeres that are extended in a limited number of cell cycles, and may be an important component of a fully quantitative model for the dynamic control of telomerase activities and telomere lengths in different types of eukaryotic cells.
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Hirsch AG, Becker D, Lamping JP, Krebber H. Unraveling the stepwise maturation of the yeast telomerase including a Cse1 and Mtr10 mediated quality control checkpoint. Sci Rep 2021; 11:22174. [PMID: 34773052 PMCID: PMC8590012 DOI: 10.1038/s41598-021-01599-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 10/29/2021] [Indexed: 01/17/2023] Open
Abstract
Telomerases elongate the ends of chromosomes required for cell immortality through their reverse transcriptase activity. By using the model organism Saccharomyces cerevisiae we defined the order in which the holoenzyme matures. First, a longer precursor of the telomerase RNA, TLC1 is transcribed and exported into the cytoplasm, where it associates with the protecting Sm-ring, the Est and the Pop proteins. This partly matured telomerase is re-imported into the nucleus via Mtr10 and a novel TLC1-import factor, the karyopherin Cse1. Remarkably, while mutations in all known transport factors result in short telomere ends, mutation in CSE1 leads to the amplification of Y′ elements in the terminal chromosome regions and thus elongated telomere ends. Cse1 does not only support TLC1 import, but also the Sm-ring stabilization on the RNA enableling Mtr10 contact and nuclear import. Thus, Sm-ring formation and import factor contact resembles a quality control step in the maturation process of the telomerase. The re-imported immature TLC1 is finally trimmed into the 1158 nucleotides long mature form via the nuclear exosome. TMG-capping of TLC1 finalizes maturation, leading to mature telomerase.
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Affiliation(s)
- Anna Greta Hirsch
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie Und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany
| | - Daniel Becker
- Philipps-Universität Marburg, Klinik für Dermatologie Und Allergologie, Baldingerstraße, 35043, Marburg, Germany
| | - Jan-Philipp Lamping
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie Und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany
| | - Heike Krebber
- Abteilung für Molekulare Genetik, Institut für Mikrobiologie Und Genetik, Göttinger Zentrum für Molekulare Biowissenschaften (GZMB), Georg-August Universität Göttingen, Göttingen, Germany.
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Sholes SL, Karimian K, Gershman A, Kelly TJ, Timp W, Greider CW. Chromosome-specific telomere lengths and the minimal functional telomere revealed by nanopore sequencing. Genome Res 2021; 32:616-628. [PMID: 34702734 PMCID: PMC8997346 DOI: 10.1101/gr.275868.121] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 10/20/2021] [Indexed: 11/26/2022]
Abstract
We developed a method to tag telomeres and measure telomere length by nanopore sequencing in the yeast S. cerevisiae. Nanopore allows long-read sequencing through the telomere, through the subtelomere, and into unique chromosomal sequence, enabling assignment of telomere length to a specific chromosome end. We observed chromosome end–specific telomere lengths that were stable over 120 cell divisions. These stable chromosome-specific telomere lengths may be explained by slow clonal variation or may represent a new biological mechanism that maintains equilibrium unique to each chromosome end. We examined the role of RIF1 and TEL1 in telomere length regulation and found that TEL1 is epistatic to RIF1 at most telomeres, consistent with the literature. However, at telomeres that lack subtelomeric Y′ sequences, tel1Δ rif1Δ double mutants had a very small, but significant, increase in telomere length compared with the tel1Δ single mutant, suggesting an influence of Y′ elements on telomere length regulation. We sequenced telomeres in a telomerase-null mutant (est2Δ) and found the minimal telomere length to be ∼75 bp. In these est2Δ mutants, there were apparent telomere recombination events at individual telomeres before the generation of survivors, and these events were significantly reduced in est2Δ rad52Δ double mutants. The rate of telomere shortening in the absence of telomerase was similar across all chromosome ends at ∼5 bp per generation. This new method gives quantitative, high-resolution telomere length measurement at each individual chromosome end and suggests possible new biological mechanisms regulating telomere length.
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Galli M, Frigerio C, Longhese MP, Clerici M. The regulation of the DNA damage response at telomeres: focus on kinases. Biochem Soc Trans 2021; 49:933-943. [PMID: 33769480 DOI: 10.1042/bst20200856] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 11/17/2022]
Abstract
The natural ends of linear chromosomes resemble those of accidental double-strand breaks (DSBs). DSBs induce a multifaceted cellular response that promotes the repair of lesions and slows down cell cycle progression. This response is not elicited at chromosome ends, which are organized in nucleoprotein structures called telomeres. Besides counteracting DSB response through specialized telomere-binding proteins, telomeres also prevent chromosome shortening. Despite of the different fate of telomeres and DSBs, many proteins involved in the DSB response also localize at telomeres and participate in telomere homeostasis. In particular, the DSB master regulators Tel1/ATM and Mec1/ATR contribute to telomere length maintenance and arrest cell cycle progression when chromosome ends shorten, thus promoting a tumor-suppressive process known as replicative senescence. During senescence, the actions of both these apical kinases and telomere-binding proteins allow checkpoint activation while bulk DNA repair activities at telomeres are still inhibited. Checkpoint-mediated cell cycle arrest also prevents further telomere erosion and deprotection that would favor chromosome rearrangements, which are known to increase cancer-associated genome instability. This review summarizes recent insights into functions and regulation of Tel1/ATM and Mec1/ATR at telomeres both in the presence and in the absence of telomerase, focusing mainly on discoveries in budding yeast.
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Affiliation(s)
- Michela Galli
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, Milano 20126, Italy
| | - Chiara Frigerio
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, Milano 20126, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, Milano 20126, Italy
| | - Michela Clerici
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Piazza della Scienza 2, Milano 20126, Italy
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Matmati S, Lambert S, Géli V, Coulon S. Telomerase Repairs Collapsed Replication Forks at Telomeres. Cell Rep 2021; 30:3312-3322.e3. [PMID: 32160539 DOI: 10.1016/j.celrep.2020.02.065] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/17/2020] [Accepted: 02/14/2020] [Indexed: 02/06/2023] Open
Abstract
Telomeres are difficult-to-replicate sites whereby replication itself may threaten telomere integrity. We investigate, in fission yeast, telomere replication dynamics in telomerase-negative cells to unmask problems associated with telomere replication. Two-dimensional gel analysis reveals that replication of telomeres is severely impaired and correlates with an accumulation of replication intermediates that arises from stalled and collapsed forks. In the absence of telomerase, Rad51, Mre11-Rad50-Nbs1 (MRN) complex, and its co-factor CtIPCtp1 become critical to maintain telomeres, indicating that homologous recombination processes these intermediates to facilitate fork restart. We further show that a catalytically dead mutant of telomerase prevents Ku recruitment to telomeres, suggesting that telomerase and Ku both compete for the binding of telomeric-free DNA ends that are likely to originate from a reversed fork. We infer that Ku removal at collapsed telomeric forks allows telomerase to repair broken telomeres, thereby shielding telomeres from homologous recombination.
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Affiliation(s)
- Samah Matmati
- Marseille Cancer Research Centre (CRCM), U1068 INSERM, UMR7258 CNRS, UM105 Aix-Marseille University, Institut Paoli-Calmettes, Ligue Nationale Contre le Cancer (équipe labellisée) Marseille, F-13009, France
| | - Sarah Lambert
- Institut Curie, PSL Research University, CNRS, UMR3348, F-91405 Orsay, France; University Paris Sud, Paris-Saclay University, CNRS, UMR3348, F-91405 Orsay, France
| | - Vincent Géli
- Marseille Cancer Research Centre (CRCM), U1068 INSERM, UMR7258 CNRS, UM105 Aix-Marseille University, Institut Paoli-Calmettes, Ligue Nationale Contre le Cancer (équipe labellisée) Marseille, F-13009, France.
| | - Stéphane Coulon
- Marseille Cancer Research Centre (CRCM), U1068 INSERM, UMR7258 CNRS, UM105 Aix-Marseille University, Institut Paoli-Calmettes, Ligue Nationale Contre le Cancer (équipe labellisée) Marseille, F-13009, France.
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14
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Akincilar SC, Chan CHT, Ng QF, Fidan K, Tergaonkar V. Non-canonical roles of canonical telomere binding proteins in cancers. Cell Mol Life Sci 2021; 78:4235-4257. [PMID: 33599797 PMCID: PMC8164586 DOI: 10.1007/s00018-021-03783-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 12/28/2020] [Accepted: 01/29/2021] [Indexed: 02/06/2023]
Abstract
Reactivation of telomerase is a major hallmark observed in 90% of all cancers. Yet paradoxically, enhanced telomerase activity does not correlate with telomere length and cancers often possess short telomeres; suggestive of supplementary non-canonical roles that telomerase might play in the development of cancer. Moreover, studies have shown that aberrant expression of shelterin proteins coupled with their release from shortening telomeres can further promote cancer by mechanisms independent of their telomeric role. While targeting telomerase activity appears to be an attractive therapeutic option, this approach has failed in clinical trials due to undesirable cytotoxic effects on stem cells. To circumvent this concern, an alternative strategy could be to target the molecules involved in the non-canonical functions of telomeric proteins. In this review, we will focus on emerging evidence that has demonstrated the non-canonical roles of telomeric proteins and their impact on tumorigenesis. Furthermore, we aim to address current knowledge gaps in telomeric protein functions and propose future research approaches that can be undertaken to achieve this.
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Affiliation(s)
- Semih Can Akincilar
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Claire Hian Tzer Chan
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Qin Feng Ng
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Kerem Fidan
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore
| | - Vinay Tergaonkar
- Division of Cancer Genetics and Therapeutics, Laboratory of NFκB Signaling, Institute of Molecular and Cell Biology (IMCB), A*STAR (Agency for Science, Technology and Research), Proteos, 61, Biopolis Drive, Singapore, 138673, Singapore.
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117593, Singapore.
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15
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Goncalves T, Zoumpoulidou G, Alvarez-Mendoza C, Mancusi C, Collopy LC, Strauss SJ, Mittnacht S, Tomita K. Selective Elimination of Osteosarcoma Cell Lines with Short Telomeres by Ataxia Telangiectasia and Rad3-Related Inhibitors. ACS Pharmacol Transl Sci 2020; 3:1253-1264. [PMID: 33344901 PMCID: PMC7737214 DOI: 10.1021/acsptsci.0c00125] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Indexed: 12/12/2022]
Abstract
![]()
To
avoid replicative senescence or telomere-induced apoptosis,
cancers employ telomere maintenance mechanisms (TMMs) involving either
the upregulation of telomerase or the acquisition of recombination-based
alternative telomere lengthening (ALT). The choice of TMM may differentially
influence cancer evolution and be exploitable in targeted therapies.
Here, we examine TMMs in a panel of 17 osteosarcoma-derived cell lines,
defining three separate groups according to TMM and the length of
telomeres maintained. Eight were ALT-positive, including the previously
uncharacterized lines, KPD and LM7. While ALT-positive lines all showed
excessive telomere length, ALT-negative cell lines fell into two groups
according to their telomere length: HOS-MNNG, OHSN, SJSA-1, HAL, 143b,
and HOS displayed subnormally short telomere length, while MG-63,
MHM, and HuO-3N1 displayed long telomeres. Hence, we further subcategorized
ALT-negative TMM into long-telomere (LT) and short-telomere (ST) maintenance groups.
Importantly, subnormally short telomeres were significantly associated
with hypersensitivity to three different therapeutics targeting the
protein kinase ataxia telangiectasia and Rad3-related (ATR) (AZD-6738/Ceralasertib,
VE-822/Berzoserib, and BAY-1895344) compared to long telomeres maintained
via ALT or telomerase. Within 24 h of ATR inhibition, cells with short
but not long telomeres displayed chromosome bridges and underwent
cell death, indicating a selective dependency on ATR for chromosome
stability. Collectively, our work provides a resource to identify
links between the mode of telomere maintenance and drug sensitivity
in osteosarcoma and indicates that telomere length predicts ATR inhibitor
sensitivity in cancer.
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Affiliation(s)
- Tomas Goncalves
- Centre for Genome Engineering and Maintenance, College of Health, Medicine and Life Sciences, Brunel University London, London UB8 3PH, United Kingdom.,Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, United Kingdom
| | - Georgia Zoumpoulidou
- Cancer Cell Signalling, UCL Cancer Institute, University College London, London WC1E 6DD, United Kingdom
| | - Carlos Alvarez-Mendoza
- Cancer Cell Signalling, UCL Cancer Institute, University College London, London WC1E 6DD, United Kingdom
| | - Caterina Mancusi
- Cancer Cell Signalling, UCL Cancer Institute, University College London, London WC1E 6DD, United Kingdom
| | - Laura C Collopy
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, United Kingdom
| | - Sandra J Strauss
- Department of Oncology, UCL Cancer Institute, University College London, London WC1E 6DD, United Kingdom.,London Sarcoma Service, University College London Hospitals Foundation Trust, London WC1E 6DD, United Kingdom
| | - Sibylle Mittnacht
- Cancer Cell Signalling, UCL Cancer Institute, University College London, London WC1E 6DD, United Kingdom
| | - Kazunori Tomita
- Centre for Genome Engineering and Maintenance, College of Health, Medicine and Life Sciences, Brunel University London, London UB8 3PH, United Kingdom.,Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, United Kingdom
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16
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Cangelosi D, Morini M, Zanardi N, Sementa AR, Muselli M, Conte M, Garaventa A, Pfeffer U, Bosco MC, Varesio L, Eva A. Hypoxia Predicts Poor Prognosis in Neuroblastoma Patients and Associates with Biological Mechanisms Involved in Telomerase Activation and Tumor Microenvironment Reprogramming. Cancers (Basel) 2020; 12:E2343. [PMID: 32825087 PMCID: PMC7563184 DOI: 10.3390/cancers12092343] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/09/2020] [Accepted: 08/17/2020] [Indexed: 12/23/2022] Open
Abstract
The biological and clinical heterogeneity of neuroblastoma (NB) demands novel biomarkers and therapeutic targets in order to drive the most appropriate treatment for each patient. Hypoxia is a condition of low-oxygen tension occurring in poorly vascularized tumor tissues. In this study, we aimed to assess the role of hypoxia in the pathogenesis of NB and at developing a new clinically relevant hypoxia-based predictor of outcome. We analyzed the gene expression profiles of 1882 untreated NB primary tumors collected at diagnosis and belonging to four existing data sets. Analyses took advantage of machine learning methods. We identified NB-hop, a seven-gene hypoxia biomarker, as a predictor of NB patient prognosis, which is able to discriminate between two populations of patients with unfavorable or favorable outcome on a molecular basis. NB-hop retained its prognostic value in a multivariate model adjusted for established risk factors and was able to additionally stratify clinically relevant groups of patients. Tumors with an unfavorable NB-hop expression showed a significant association with telomerase activation and a hypoxic, immunosuppressive, poorly differentiated, and apoptosis-resistant tumor microenvironment. NB-hop defines a new population of NB patients with hypoxic tumors and unfavorable prognosis and it represents a critical factor for the stratification and treatment of NB patients.
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Affiliation(s)
- Davide Cangelosi
- Laboratory of Molecular Biology, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy; (M.M.); (N.Z.); (L.V.); (A.E.)
| | - Martina Morini
- Laboratory of Molecular Biology, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy; (M.M.); (N.Z.); (L.V.); (A.E.)
| | - Nicolò Zanardi
- Laboratory of Molecular Biology, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy; (M.M.); (N.Z.); (L.V.); (A.E.)
| | - Angela Rita Sementa
- Laboratory of Pathology, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy;
| | - Marco Muselli
- Institute of Electronics, Computer and Telecommunication Engineering, Italian National Research Council, 16149 Genova, Italy;
| | - Massimo Conte
- Pediatric Oncology Unit, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy; (M.C.); (A.G.)
| | - Alberto Garaventa
- Pediatric Oncology Unit, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy; (M.C.); (A.G.)
| | - Ulrich Pfeffer
- Integrated Oncology Therapies Department, Molecular Pathology, IRCCS Ospedale Policlinico San Martino, 16132 Genova, Italy;
| | - Maria Carla Bosco
- Laboratory of Molecular Biology, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy; (M.M.); (N.Z.); (L.V.); (A.E.)
| | - Luigi Varesio
- Laboratory of Molecular Biology, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy; (M.M.); (N.Z.); (L.V.); (A.E.)
| | - Alessandra Eva
- Laboratory of Molecular Biology, IRCCS Istituto Giannina Gaslini, 16147 Genova, Italy; (M.M.); (N.Z.); (L.V.); (A.E.)
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17
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Reynolds BA, Oli MW, Oli MK. Eco-oncology: Applying ecological principles to understand and manage cancer. Ecol Evol 2020; 10:8538-8553. [PMID: 32884638 PMCID: PMC7452771 DOI: 10.1002/ece3.6590] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 06/15/2020] [Accepted: 06/17/2020] [Indexed: 12/25/2022] Open
Abstract
Cancer is a disease of single cells that expresses itself at the population level. The striking similarities between initiation and growth of tumors and dynamics of biological populations, and between metastasis and ecological invasion and community dynamics suggest that oncology can benefit from an ecological perspective to improve our understanding of cancer biology. Tumors can be viewed as complex, adaptive, and evolving systems as they are spatially and temporally heterogeneous, continually interacting with each other and with the microenvironment and evolving to increase the fitness of the cancer cells. We argue that an eco-evolutionary perspective is essential to understand cancer biology better. Furthermore, we suggest that ecologically informed therapeutic approaches that combine standard of care treatments with strategies aimed at decreasing the evolutionary potential and fitness of neoplastic cells, such as disrupting cell-to-cell communication and cooperation, and preventing successful colonization of distant organs by migrating cancer cells, may be effective in managing cancer as a chronic condition.
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Affiliation(s)
- Brent A. Reynolds
- Department of NeurosurgeryCollege of MedicineUniversity of FloridaGainesvilleFLUSA
| | - Monika W. Oli
- Department of Microbiology and Cell ScienceInstitute of Food and Agricultural SciencesUniversity of FloridaGainesvilleFLUSA
| | - Madan K. Oli
- Department of Wildlife Ecology and ConservationInstitute of Food and Agricultural SciencesUniversity of FloridaGainesvilleFLUSA
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18
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Insights into the structure and function of Est3 from the Hansenula polymorpha telomerase. Sci Rep 2020; 10:11109. [PMID: 32632130 PMCID: PMC7338525 DOI: 10.1038/s41598-020-68107-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 06/19/2020] [Indexed: 12/12/2022] Open
Abstract
Telomerase is a ribonucleoprotein enzyme, which maintains genome integrity in eukaryotes and ensures continuous cellular proliferation. Telomerase holoenzyme from the thermotolerant yeast Hansenula polymorpha, in addition to the catalytic subunit (TERT) and telomerase RNA (TER), contains accessory proteins Est1 and Est3, which are essential for in vivo telomerase function. Here we report the high-resolution structure of Est3 from Hansenula polymorpha (HpEst3) in solution, as well as the characterization of its functional relationships with other components of telomerase. The overall structure of HpEst3 is similar to that of Est3 from Saccharomyces cerevisiae and human TPP1. We have shown that telomerase activity in H. polymorpha relies on both Est3 and Est1 proteins in a functionally symmetrical manner. The absence of either Est3 or Est1 prevents formation of a stable ribonucleoprotein complex, weakens binding of a second protein to TER, and decreases the amount of cellular TERT, presumably due to the destabilization of telomerase RNP. NMR probing has shown no direct in vitro interactions of free Est3 either with the N-terminal domain of TERT or with DNA or RNA fragments mimicking the probable telomerase environment. Our findings corroborate the idea that telomerase possesses the evolutionarily variable functionality within the conservative structural context.
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19
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Barral A, Déjardin J. Telomeric Chromatin and TERRA. J Mol Biol 2020; 432:4244-4256. [DOI: 10.1016/j.jmb.2020.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 03/03/2020] [Accepted: 03/03/2020] [Indexed: 01/01/2023]
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20
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A pH-responsive colorimetric detection of human telomerase RNA based on a three-dimensional DNA amplifier. Anal Chim Acta 2020; 1111:67-74. [PMID: 32312398 DOI: 10.1016/j.aca.2020.03.049] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 03/21/2020] [Accepted: 03/23/2020] [Indexed: 11/22/2022]
Abstract
Human telomerase RNA (hTR), one of the essential components of telomerase, serves as a reverse template to add repeated segments of (TTAGGG)n to the 3' end of telomere DNA for maintaining the length of telomere DNA, endowing cells indefinite proliferation capability. Expression level of hTR displays a close relationship with tumor grade. Inspired by the mechanism of urease hydrolyzing urea to release ammonia and elevate the pH value of the sample solution, we developed a facile and novel pH-responsive colorimetric strategy for hTR detection by incorporating catalyzed hairpin assembly (CHA) onto the magnetic beads (MBs). The CHA process was initiated by target hTR and recycled via toehold binding and branch migration, thereby abundant urease being anchored on the surface of MBs. After separated by an external magnetic field, the assembled urease catalyzed the hydrolysis of urea to release a large amount of ammonia, which gave rise to a remarkable pH signal. Thus, quantification of hTR was achieved by measuring the solution pH via a hand-held pH meter or visualizing the solution color with the assistance of the pH indicator phenol red. The proposed sensing platform exhibits excellent performance toward hTR with a detection limit as low as 41 pM and a remarkable sequence selectivity, being able to differentiate a single mismatch in the target DNA. The pH-responsive colorimetric sensing platform contributes to introducing pH-related portable strategies into the detections of numerous universal biomarkers such as nucleic acids and proteins.
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21
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Srinivas N, Rachakonda S, Kumar R. Telomeres and Telomere Length: A General Overview. Cancers (Basel) 2020; 12:E558. [PMID: 32121056 PMCID: PMC7139734 DOI: 10.3390/cancers12030558] [Citation(s) in RCA: 131] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/24/2020] [Accepted: 02/26/2020] [Indexed: 02/06/2023] Open
Abstract
Telomeres are highly conserved tandem nucleotide repeats that include proximal double-stranded and distal single-stranded regions that in complex with shelterin proteins afford protection at chromosomal ends to maintain genomic integrity. Due to the inherent limitations of DNA replication and telomerase suppression in most somatic cells, telomeres undergo age-dependent incremental attrition. Short or dysfunctional telomeres are recognized as DNA double-stranded breaks, triggering cells to undergo replicative senescence. Telomere shortening, therefore, acts as a counting mechanism that drives replicative senescence by limiting the mitotic potential of cells. Telomere length, a complex hereditary trait, is associated with aging and age-related diseases. Epidemiological data, in general, support an association with varying magnitudes between constitutive telomere length and several disorders, including cancers. Telomere attrition is also influenced by oxidative damage and replicative stress caused by genetic, epigenetic, and environmental factors. Several single nucleotide polymorphisms at different loci, identified through genome-wide association studies, influence inter-individual variation in telomere length. In addition to genetic factors, environmental factors also influence telomere length during growth and development. Telomeres hold potential as biomarkers that reflect the genetic predisposition together with the impact of environmental conditions and as targets for anti-cancer therapies.
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Affiliation(s)
| | | | - Rajiv Kumar
- Division of Functional Genome Analysis, German Cancer Research Center, Im Neunheimer Feld 580, 69120 Heidelberg, Germany; (N.S.); (S.R.)
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22
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Holič R, Pokorná L, Griač P. Metabolism of phospholipids in the yeast
Schizosaccharomyces pombe. Yeast 2019; 37:73-92. [DOI: 10.1002/yea.3451] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/26/2019] [Accepted: 11/27/2019] [Indexed: 12/28/2022] Open
Affiliation(s)
- Roman Holič
- Centre of Biosciences, Slovak Academy of Sciences Institute of Animal Biochemistry and Genetics Dúbravská cesta 9 Bratislava Slovakia
| | - Lucia Pokorná
- Centre of Biosciences, Slovak Academy of Sciences Institute of Animal Biochemistry and Genetics Dúbravská cesta 9 Bratislava Slovakia
| | - Peter Griač
- Centre of Biosciences, Slovak Academy of Sciences Institute of Animal Biochemistry and Genetics Dúbravská cesta 9 Bratislava Slovakia
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23
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Liu Y, Fan P, Yang Y, Xu C, Huang Y, Li D, Qing Q, Sun C, Zhou H. Human papillomavirus and human telomerase RNA component gene in cervical cancer progression. Sci Rep 2019; 9:15926. [PMID: 31685833 PMCID: PMC6828729 DOI: 10.1038/s41598-019-52195-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 09/24/2019] [Indexed: 01/05/2023] Open
Abstract
This study aimed to examine hTERC gene in different grades of cervical intraepithelial neoplasia (CIN) and cervical cancer, and the association between hTERC and high risk-human papillomavirus (HR-HPV) infection. Patients who underwent cervical cancer screening at the Second Affiliated Hospital of Kunming Medical University between October 2010 and December 2011 were enrolled. All patients underwent liquid-based cytology test and hybrid capture 2 (HC2) for HPV detection. hTERC was examined using fluorescence in situ hybridization (FISH). Cervical colposcopy biopsy was performed if any of the three results was positive. HC2, FISH, and pathology were compared. A total of 1200 women underwent screening, 150 patients underwent cervical biopsy: 32 in the normal group, 38 in the CIN1 group, 66 in the CIN2/3 group, and 14 in the invasive cervical cancer group. More patients had HR-HPV infection in the CIN2/3 group and ICC group compared with the CIN1 group. hTERC increased with increasing histological dysplasia. There was significant difference in hTERC positive rate between each of the three groups. More patients with hTERC gene amplification were observed in the positive HR-HPV group than in the HR-HPV negative group. In conclusion, hTERC is a potential marker for precancerous cervical cancer lesions. hTERC might be correlated with HR-HPV infection in cervical diseases.
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Affiliation(s)
- Yang Liu
- Department of Reproductive, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650101, P.R. China
| | - Pianping Fan
- Department of Gynecology, LinFen Central Hospital of Shanxi Province, LinFen, Shanxi, 041000, P.R. China
| | - Yingying Yang
- Department of Gynecology, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650101, P.R. China
| | - Changjun Xu
- Department of Gynecology, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650101, P.R. China
| | - Yajuan Huang
- Department of Gynecology, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650101, P.R. China
| | - Daizhu Li
- Department of Gynecology, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650101, P.R. China
| | - Qing Qing
- Department of Gynecology, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650101, P.R. China
| | - Chunyi Sun
- Department of Gynecology, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650101, P.R. China.
| | - Honglin Zhou
- Department of Gynecology, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, 650101, P.R. China.
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24
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Denham J. Telomere regulation: lessons learnt from mice and men, potential opportunities in horses. Anim Genet 2019; 51:3-13. [PMID: 31637754 DOI: 10.1111/age.12870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2019] [Indexed: 11/26/2022]
Abstract
Telomeres are genetically conserved nucleoprotein complexes located at the ends of chromosomes that preserve genomic stability. In large mammals, somatic cell telomeres shorten with age, owing to the end replication problem and lack of telomere-lengthening events (e.g. telomerase and ALT activity). Therefore, telomere length reflects cellular replicative reserve and mitotic potential. Environmental insults can accelerate telomere attrition in response to cell division and DNA damage. As such, telomere shortening is considered one of the major hallmarks of ageing. Much effort has been dedicated to understanding the environmental perturbations that accelerate telomere attrition and therapeutic strategies to preserve or extend telomeres. As telomere dynamics seem to reflect cumulative cellular stress, telomere length could serve as a biomarker of animal welfare. The assessment of telomere dynamics (i.e. rate of shortening) in conjunction with telomere-regulating genes and telomerase activity in racehorses could monitor long-term animal health, yet it could also provide some unique opportunities to address particular limitations with the use of other animal models in telomere research. Considering the ongoing efforts to optimise the health and welfare of equine athletes, the purpose of this review is to discuss the potential utility of assessing telomere length in Thoroughbred racehorses. A brief review of telomere biology in large and small mammals will be provided, followed by discussion on the biological implications of telomere length and environmental (e.g. lifestyle) factors that accelerate or attenuate telomere attrition. Finally, the utility of quantifying telomere dynamics in horses will be offered with directions for future research.
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Affiliation(s)
- J Denham
- School of Health and Biomedical Sciences, Bundoora West Campus, RMIT University, Room 53, Level 4, Building 202, Bundoora, VIC, 3083, Australia
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25
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Hu Y, Bennett HW, Liu N, Moravec M, Williams JF, Azzalin CM, King MC. RNA-DNA Hybrids Support Recombination-Based Telomere Maintenance in Fission Yeast. Genetics 2019; 213:431-447. [PMID: 31405990 PMCID: PMC6781888 DOI: 10.1534/genetics.119.302606] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 08/09/2019] [Indexed: 11/18/2022] Open
Abstract
A subset of cancers rely on telomerase-independent mechanisms to maintain their chromosome ends. The predominant "alternative lengthening of telomeres" pathway appears dependent on homology-directed repair (HDR) to maintain telomeric DNA. However, the molecular changes needed for cells to productively engage in telomeric HDR are poorly understood. To gain new insights into this transition, we monitored the state of telomeres during serial culture of fission yeast (Schizosaccharomyces pombe) lacking the telomerase recruitment factor Ccq1. Rad52 is loaded onto critically short telomeres shortly after germination despite continued telomere erosion, suggesting that recruitment of recombination factors is not sufficient to maintain telomeres in the absence of telomerase function. Instead, survivor formation coincides with the derepression of telomeric repeat-containing RNA (TERRA). In this context, degradation of TERRA associated with the telomere in the form of R-loops drives a severe growth crisis, ultimately leading to a novel type of survivor with linear chromosomes and altered cytological telomere characteristics, including the loss of the shelterin component Rap1 (but not the TRF1/TRF2 ortholog, Taz1) from the telomere. We demonstrate that deletion of Rap1 is protective in this context, preventing the growth crisis that is otherwise triggered by degradation of telomeric R-loops in survivors with linear chromosomes. These findings suggest that upregulation of telomere-engaged TERRA, or altered recruitment of shelterin components, can support telomerase-independent telomere maintenance.
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Affiliation(s)
- Yan Hu
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520-8002
| | - Henrietta W Bennett
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520-8002
| | - Na Liu
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520-8002
| | - Martin Moravec
- Institute of Biochemistry (IBC), Eidgenössische Technische Hochschule Zürich (ETHZ), 8093, Switzerland
| | - Jessica F Williams
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520-8002
| | - Claus M Azzalin
- Instituto de Medicina Molecular João Lobo Antunes (iMM), Faculdade de Medicina da Universidade de Lisboa, 1649-028, Portugal
| | - Megan C King
- Department of Cell Biology, Yale School of Medicine, New Haven, Connecticut 06520-8002
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Menin L, Colombo CV, Maestrini G, Longhese MP, Clerici M. Tel1/ATM Signaling to the Checkpoint Contributes to Replicative Senescence in the Absence of Telomerase. Genetics 2019; 213:411-429. [PMID: 31391264 PMCID: PMC6781906 DOI: 10.1534/genetics.119.302391] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 07/27/2019] [Indexed: 11/18/2022] Open
Abstract
Telomeres progressively shorten at every round of DNA replication in the absence of telomerase. When they become critically short, telomeres trigger replicative senescence by activating a DNA damage response that is governed by the Mec1/ATR and Tel1/ATM protein kinases. While Mec1/ATR is known to block cell division when extended single-stranded DNA (ssDNA) accumulates at eroded telomeres, the molecular mechanism by which Tel1/ATM promotes senescence is still unclear. By characterizing a Tel1-hy184 mutant variant that compensates for the lack of Mec1 functions, we provide evidence that Tel1 promotes senescence by signaling to a Rad9-dependent checkpoint. Tel1-hy184 anticipates senescence onset in telomerase-negative cells, while the lack of Tel1 or the expression of a kinase-defective (kd) Tel1 variant delays it. Both Tel1-hy184 and Tel1-kd do not alter ssDNA generation at telomeric DNA ends. Furthermore, Rad9 and (only partially) Mec1 are responsible for the precocious senescence promoted by Tel1-hy184. This precocious senescence is mainly caused by the F1751I, D1985N, and E2133K amino acid substitutions, which are located in the FRAP-ATM-TRAPP domain of Tel1 and also increase Tel1 binding to DNA ends. Altogether, these results indicate that Tel1 induces replicative senescence by directly signaling dysfunctional telomeres to the checkpoint machinery.
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Affiliation(s)
- Luca Menin
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milano 20126, Italy
| | - Chiara Vittoria Colombo
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milano 20126, Italy
| | - Giorgia Maestrini
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milano 20126, Italy
| | - Maria Pia Longhese
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milano 20126, Italy
| | - Michela Clerici
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano-Bicocca, Milano 20126, Italy
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27
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Červenák F, Juríková K, Devillers H, Kaffe B, Khatib A, Bonnell E, Sopkovičová M, Wellinger RJ, Nosek J, Tzfati Y, Neuvéglise C, Tomáška Ľ. Identification of telomerase RNAs in species of the Yarrowia clade provides insights into the co-evolution of telomerase, telomeric repeats and telomere-binding proteins. Sci Rep 2019; 9:13365. [PMID: 31527614 PMCID: PMC6746865 DOI: 10.1038/s41598-019-49628-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 07/29/2019] [Indexed: 12/17/2022] Open
Abstract
Telomeric repeats in fungi of the subphylum Saccharomycotina exhibit great inter- and intra-species variability in length and sequence. Such variations challenged telomeric DNA-binding proteins that co-evolved to maintain their functions at telomeres. Here, we compare the extent of co-variations in telomeric repeats, encoded in the telomerase RNAs (TERs), and the repeat-binding proteins from 13 species belonging to the Yarrowia clade. We identified putative TER loci, analyzed their sequence and secondary structure conservation, and predicted functional elements. Moreover, in vivo complementation assays with mutant TERs showed the functional importance of four novel TER substructures. The TER-derived telomeric repeat unit of all species, except for one, is 10 bp long and can be represented as 5′-TTNNNNAGGG-3′, with repeat sequence variations occuring primarily outside the vertebrate telomeric motif 5′-TTAGGG-3′. All species possess a homologue of the Yarrowia lipolytica Tay1 protein, YlTay1p. In vitro, YlTay1p displays comparable DNA-binding affinity to all repeat variants, suggesting a conserved role among these species. Taken together, these results add significant insights into the co-evolution of TERs, telomeric repeats and telomere-binding proteins in yeasts.
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Affiliation(s)
- Filip Červenák
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Katarína Juríková
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Hugo Devillers
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Binyamin Kaffe
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem, 91904, Israel
| | - Areej Khatib
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem, 91904, Israel
| | - Erin Bonnell
- Department of Microbiology and Infectiology, RNA Group, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Martina Sopkovičová
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Raymund J Wellinger
- Department of Microbiology and Infectiology, RNA Group, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Jozef Nosek
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia
| | - Yehuda Tzfati
- Department of Genetics, The Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Safra Campus, Jerusalem, 91904, Israel.
| | - Cécile Neuvéglise
- Micalis Institute, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.
| | - Ľubomír Tomáška
- Departments of Genetics and Biochemistry, Comenius University in Bratislava, Faculty of Natural Sciences, Ilkovičova 6, Mlynská dolina, 84215, Bratislava, Slovakia.
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28
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Reis H, Schwebs M, Dietz S, Janzen CJ, Butter F. TelAP1 links telomere complexes with developmental expression site silencing in African trypanosomes. Nucleic Acids Res 2019; 46:2820-2833. [PMID: 29385523 PMCID: PMC5888660 DOI: 10.1093/nar/gky028] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 01/25/2018] [Indexed: 11/14/2022] Open
Abstract
During its life cycle, Trypanosoma brucei shuttles between a mammalian host and the tsetse fly vector. In the mammalian host, immune evasion of T. brucei bloodstream form (BSF) cells relies on antigenic variation, which includes monoallelic expression and periodic switching of variant surface glycoprotein (VSG) genes. The active VSG is transcribed from only 1 of the 15 subtelomeric expression sites (ESs). During differentiation from BSF to the insect-resident procyclic form (PCF), the active ES is transcriptionally silenced. We used mass spectrometry-based interactomics to determine the composition of telomere protein complexes in T. brucei BSF and PCF stages to learn more about the structure and functions of telomeres in trypanosomes. Our data suggest a different telomere complex composition in the two forms of the parasite. One of the novel telomere-associated proteins, TelAP1, forms a complex with telomeric proteins TbTRF, TbRAP1 and TbTIF2 and influences ES silencing kinetics during developmental differentiation.
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Affiliation(s)
- Helena Reis
- Department of Cell & Developmental Biology, Biocenter University of Würzburg, Würzburg 97074, Germany
| | - Marie Schwebs
- Department of Cell & Developmental Biology, Biocenter University of Würzburg, Würzburg 97074, Germany
| | - Sabrina Dietz
- Quantitative Proteomics, Institute of Molecular Biology (IMB), Mainz 55128, Germany
| | - Christian J Janzen
- Department of Cell & Developmental Biology, Biocenter University of Würzburg, Würzburg 97074, Germany
| | - Falk Butter
- Quantitative Proteomics, Institute of Molecular Biology (IMB), Mainz 55128, Germany
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29
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Armstrong CA, Moiseeva V, Collopy LC, Pearson SR, Ullah TR, Xi ST, Martin J, Subramaniam S, Marelli S, Amelina H, Tomita K. Fission yeast Ccq1 is a modulator of telomerase activity. Nucleic Acids Res 2019; 46:704-716. [PMID: 29216371 PMCID: PMC5778466 DOI: 10.1093/nar/gkx1223] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 11/27/2017] [Indexed: 01/05/2023] Open
Abstract
Shelterin, the telomeric protein complex, plays a crucial role in telomere homeostasis. In fission yeast, telomerase is recruited to chromosome ends by the shelterin component Tpz1 and its binding partner Ccq1, where telomerase binds to the 3' overhang to add telomeric repeats. Recruitment is initiated by the interaction of Ccq1 with the telomerase subunit Est1. However, how telomerase is released following elongation remains to be established. Here, we show that Ccq1 also has a role in the suppression of telomere elongation, when coupled with the Clr4 histone H3 methyl-transferase complex and the Clr3 histone deacetylase and nucleosome remodelling complex, SHREC. We have dissected the functions of Ccq1 by establishing a Ccq1-Est1 fusion system, which bypasses the telomerase recruitment step. We demonstrate that Ccq1 forms two distinct complexes for positive and negative telomerase regulation, with Est1 and Clr3 respectively. The negative form of Ccq1 promotes dissociation of Ccq1-telomerase from Tpz1, thereby restricting local telomerase activity. The Clr4 complex also has a negative regulation activity with Ccq1, independently of SHREC. Thus, we propose a model in which Ccq1-Est1 recruits telomerase to mediate telomere extension, whilst elongated telomeric DNA recruits Ccq1 with the chromatin-remodelling complexes, which in turn releases telomerase from the telomere.
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Affiliation(s)
- Christine A Armstrong
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, UK
| | - Vera Moiseeva
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, UK
| | - Laura C Collopy
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, UK
| | - Siân R Pearson
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, UK
| | - Tomalika R Ullah
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, UK.,MSc Human Molecular Genetics, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Shidong T Xi
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, UK.,Faculty of Life Sciences, University College London, London WC1E 6BT, UK
| | - Jennifer Martin
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, UK.,MSc Human Molecular Genetics, Faculty of Medicine, Imperial College London, London SW7 2AZ, UK
| | - Shaan Subramaniam
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, UK.,Faculty of Life Sciences, University College London, London WC1E 6BT, UK
| | - Sara Marelli
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, UK
| | - Hanna Amelina
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, UK
| | - Kazunori Tomita
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London WC1E 6DD, UK
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30
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Li JJ, Yan YY, Sun HM, Liu Y, Su CY, Chen HB, Zhang JY. Anti-Cancer Effects of Pristimerin and the Mechanisms: A Critical Review. Front Pharmacol 2019; 10:746. [PMID: 31354475 PMCID: PMC6640652 DOI: 10.3389/fphar.2019.00746] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 06/11/2019] [Indexed: 12/16/2022] Open
Abstract
As a quinonemethide triterpenoid extracted from species of the Celastraceae and Hippocrateaceae, pristimerin has been shown potent anti-cancer effects. Specifically, it was found that pristimerin can affect many tumor-related processes, such as apoptosis, autophagy, migration and invasion, vasculogenesis, and drug resistance. Various molecular targets or signaling pathways are also involved, such as cyclins, reactive oxygen species (ROS), microRNA, nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and PI3K/AKT/mammalian target of rapamycin (mTOR) pathways. In this review, we will focus on the research about pristimerin-induced anti-cancer activities to achieve a deeper understanding of the targets and mechanisms, which offer evidences suggesting that pristimerin can be a potent anti-cancer drug.
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Affiliation(s)
- Jia-Jun Li
- Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Yan-Yan Yan
- Institute of Respiratory and Occupational Diseases, Collaborative Innovation Center for Cancer, Medical College, Shanxi Datong University, Datong, China.,School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
| | | | - Yun Liu
- Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Chao-Yue Su
- Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Hu-Biao Chen
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
| | - Jian-Ye Zhang
- Guangdong Provincial Key Laboratory of Molecular Target & Clinical Pharmacology, School of Pharmaceutical Sciences and the Fifth Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
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31
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Petrova OA, Mantsyzov AB, Rodina EV, Efimov SV, Hackenberg C, Hakanpää J, Klochkov VV, Lebedev AA, Chugunova AA, Malyavko AN, Zatsepin TS, Mishin AV, Zvereva MI, Lamzin VS, Dontsova OA, Polshakov VI. Structure and function of the N-terminal domain of the yeast telomerase reverse transcriptase. Nucleic Acids Res 2019; 46:1525-1540. [PMID: 29294091 PMCID: PMC5814841 DOI: 10.1093/nar/gkx1275] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 12/19/2017] [Indexed: 12/19/2022] Open
Abstract
The elongation of single-stranded DNA repeats at the 3′-ends of chromosomes by telomerase is a key process in maintaining genome integrity in eukaryotes. Abnormal activation of telomerase leads to uncontrolled cell division, whereas its down-regulation is attributed to ageing and several pathologies related to early cell death. Telomerase function is based on the dynamic interactions of its catalytic subunit (TERT) with nucleic acids—telomerase RNA, telomeric DNA and the DNA/RNA heteroduplex. Here, we present the crystallographic and NMR structures of the N-terminal (TEN) domain of TERT from the thermotolerant yeast Hansenula polymorpha and demonstrate the structural conservation of the core motif in evolutionarily divergent organisms. We identify the TEN residues that are involved in interactions with the telomerase RNA and in the recognition of the ‘fork’ at the distal end of the DNA product/RNA template heteroduplex. We propose that the TEN domain assists telomerase biological function and is involved in restricting the size of the heteroduplex during telomere repeat synthesis.
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Affiliation(s)
- Olga A Petrova
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Alexey B Mantsyzov
- Centre for Magnetic Tomography and Spectroscopy, Faculty of Fundamental Medicine, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Elena V Rodina
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Sergey V Efimov
- NMR Laboratory, Institute of Physics, Kazan Federal University, 18 Kremlevskaya, Kazan 420008, Russia
| | - Claudia Hackenberg
- European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany
| | - Johanna Hakanpää
- European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany
| | - Vladimir V Klochkov
- NMR Laboratory, Institute of Physics, Kazan Federal University, 18 Kremlevskaya, Kazan 420008, Russia
| | - Andrej A Lebedev
- Research Complex at Harwell, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Didcot, UK
| | - Anastasia A Chugunova
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Alexander N Malyavko
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Timofei S Zatsepin
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Alexey V Mishin
- Laboratory for Structural Biology of GPCRs, Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Maria I Zvereva
- Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Victor S Lamzin
- European Molecular Biology Laboratory, Notkestrasse 85, 22607 Hamburg, Germany
| | - Olga A Dontsova
- A.N. Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Skolkovo Institute of Science and Technology, Moscow, Russia
| | - Vladimir I Polshakov
- Centre for Magnetic Tomography and Spectroscopy, Faculty of Fundamental Medicine, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
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32
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Nguyen THD, Collins K, Nogales E. Telomerase structures and regulation: shedding light on the chromosome end. Curr Opin Struct Biol 2019; 55:185-193. [PMID: 31202023 DOI: 10.1016/j.sbi.2019.04.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 03/28/2019] [Accepted: 04/29/2019] [Indexed: 02/06/2023]
Abstract
During genome replication, telomerase adds repeats to the ends of chromosomes to balance the loss of telomeric DNA. The regulation of telomerase activity is of medical relevance, as it has been implicated in human diseases such as cancer, as well as in aging. Until recently, structural information on this enzyme that would facilitate its clinical manipulation had been lacking due to telomerase very low abundance in cells. Recent cryo-EM structures of both the human and Tetrahymena thermophila telomerases have provided a picture of both the shared catalytic core of telomerase and its interaction with species-specific factors that play different roles in telomerase RNP assembly and function. We discuss also progress toward an understanding of telomerase RNP biogenesis and telomere recruitment from recent studies.
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Affiliation(s)
- Thi Hoang Duong Nguyen
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA; California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA 94720, USA; Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Miller Institute for Basic Research in Science, University of California, Berkeley, CA 94720, USA.
| | - Kathleen Collins
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA; California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA 94720, USA
| | - Eva Nogales
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA; California Institute for Quantitative Biology (QB3), University of California, Berkeley, CA 94720, USA; Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, CA 94720, USA
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33
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Sayed ME, Cheng A, Yadav GP, Ludlow AT, Shay JW, Wright WE, Jiang QX. Catalysis-dependent inactivation of human telomerase and its reactivation by intracellular telomerase-activating factors (iTAFs). J Biol Chem 2019; 294:11579-11596. [PMID: 31186347 DOI: 10.1074/jbc.ra118.007234] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 06/04/2019] [Indexed: 12/17/2022] Open
Abstract
Human telomerase maintains genome stability by adding telomeric repeats to the ends of linear chromosomes. Although previous studies have revealed profound insights into telomerase functions, the low cellular abundance of functional telomerase and the difficulties in quantifying its activity leave its thermodynamic and kinetic properties only partially characterized. Employing a stable cell line overexpressing both the human telomerase RNA component and the N-terminally biotinylated human telomerase reverse transcriptase and using a newly developed method to count individual extension products, we demonstrate here that human telomerase holoenzymes contain fast- and slow-acting catalytic sites. Surprisingly, both active sites became inactive after two consecutive rounds of catalysis, named single-run catalysis. The fast active sites turned off ∼40-fold quicker than the slow ones and exhibited higher affinities to DNA substrates. In a dimeric enzyme, the two active sites work in tandem, with the faster site functioning before the slower one, and in the monomeric enzyme, the active sites also perform single-run catalysis. Interestingly, inactive enzymes could be reactivated by intracellular telomerase-activating factors (iTAFs) from multiple cell types. We conclude that the single-run catalysis and the iTAF-triggered reactivation serve as an unprecedented control circuit for dynamic regulation of telomerase. They endow native telomerase holoenzymes with the ability to match their total number of active sites to the number of telomeres they extend. We propose that the exquisite kinetic control of telomerase activity may play important roles in both cell division and cell aging.
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Affiliation(s)
- Mohammed E Sayed
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390.,School of Kinesiology Integrative Molecular Genetics Lab, University of Michigan, Ann Arbor, Michigan 48109
| | - Ao Cheng
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390.,Department of Diagnostic and Biological Sciences, University of Minnesota, Minneapolis, Minnesota 55455
| | - Gaya P Yadav
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390.,Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611
| | - Andrew T Ludlow
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390.,School of Kinesiology Integrative Molecular Genetics Lab, University of Michigan, Ann Arbor, Michigan 48109
| | - Jerry W Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Woodring E Wright
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Qiu-Xing Jiang
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390 .,Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida 32611
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34
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Doğan F, Özateş NP, Bağca BG, Abbaszadeh Z, Söğütlü F, Gasımlı R, Gündüz C, Biray Avcı Ç. Investigation of the effect of telomerase inhibitor BIBR1532 on breast cancer and breast cancer stem cells. J Cell Biochem 2019; 120:1282-1293. [PMID: 30368861 DOI: 10.1002/jcb.27089] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 04/26/2018] [Indexed: 01/24/2023]
Abstract
It is emphasized that cancer stem cells (CSCs) forming the subpopulation of tumour cells are responsible for tumour growth, metastasis, and cancer drug resistance. Inadequate response to conventional therapy in breast cancer leads researchers to find new treatment methods and literature surveys that support CSC studies. A selective anticancer agent BIBR1532 inhibits the telomerase enzyme. Many of the chemotherapeutic drugs used in clinical trials have harmful effects, but the advantage of telomerase-based inhibitors is that they are less toxic to healthy tissues. The phosphoinositide 3-kinase (PI3K)/serine/threonine kinase (Akt)/mammalian target of rapamycin (mTOR) pathway is common in breast cancer, and the interaction between the mTOR pathway and human telomerase reverse transcriptase (hTERT) is essential for the survival of cancer cells. In our study, we treated MCF-7, breast cancer stem cell (BCSC) and normal breast epithelial cell MCF10A with the BIBR1532 inhibitor. The IC 50 doses for the 48th hour of BIBR1532 treatment were detected as 34.59 μM in MCF-7, 29.91 μM in BCSCs, and 29.07 μM in MCF10A. It has been observed that this agent induces apoptosis in the BCSC and MCF-7 cell lines. According to the results of cell cycle analysis, G 2 /M phase accumulation was observed in BCSC and MCF-7 cell lines. It has also been shown that BIBR1532 suppresses telomerase activity in BCSC and MCF-7. The effect of BIBR1532 on the mTOR signalling pathway has been investigated for the first time in this study. It is thought that the telomerase inhibitor may bring a new approach to the treatment and it may be useful in the treatment of CSCs.
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Affiliation(s)
- Fatma Doğan
- Department of Medical Biology, Ege University Medical School, Bornova, Turkey
| | | | - Bakiye Göker Bağca
- Department of Medical Biology, Ege University Medical School, Bornova, Turkey
| | - Zeka Abbaszadeh
- Department of Medical Biology, Ege University Medical School, Bornova, Turkey
| | - Fatma Söğütlü
- Department of Medical Biology, Ege University Medical School, Bornova, Turkey
| | - Röya Gasımlı
- Department of Medical Biology, Ege University Medical School, Bornova, Turkey
| | - Cumhur Gündüz
- Department of Medical Biology, Ege University Medical School, Bornova, Turkey
| | - Çığır Biray Avcı
- Department of Medical Biology, Ege University Medical School, Bornova, Turkey
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35
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de Groot SC, Sliedregt K, van Benthem PPG, Rivolta MN, Huisman MA. Building an Artificial Stem Cell Niche: Prerequisites for Future 3D-Formation of Inner Ear Structures-Toward 3D Inner Ear Biotechnology. Anat Rec (Hoboken) 2019; 303:408-426. [PMID: 30635991 PMCID: PMC7065153 DOI: 10.1002/ar.24067] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 06/03/2018] [Accepted: 08/23/2018] [Indexed: 01/19/2023]
Abstract
In recent years, there has been an increased interest in stem cells for the purpose of regenerative medicine to deliver a wide range of therapies to treat many diseases. However, two‐dimensional cultures of stem cells are of limited use when studying the mechanism of pathogenesis of diseases and the feasibility of a treatment. Therefore, research is focusing on the strengths of stem cells in the three‐dimensional (3D) structures mimicking organs, that is, organoids, or organ‐on‐chip, for modeling human biology and disease. As 3D technology advances, it is necessary to know which signals stem cells need to multiply and differentiate into complex structures. This holds especially true for the complex 3D structure of the inner ear. Recent work suggests that although other factors play a role, the extracellular matrix (ECM), including its topography, is crucial to mimic a stem cell niche in vitro and to drive stem cells toward the formation of the tissue of interest. Technological developments have led to the investigation of biomaterials that closely resemble the native ECM. In the fast forward moving research of organoids and organs‐on‐chip, the inner ear has hardly received attention. This review aims to provide an overview, by describing the general context in which cells, matrix and morphogens cooperate in order to build a tissue, to facilitate research in 3D inner ear technology. Anat Rec, 303:408–426, 2020. © 2019 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.
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Affiliation(s)
| | - Karen Sliedregt
- Wageningen University and Research, Wageningen, the Netherlands
| | - Peter Paul G van Benthem
- Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Leiden, the Netherlands
| | - Marcelo N Rivolta
- Centre for Stem Cell Biology, Department of Biomedical Science, University of Sheffield, Sheffield, UK
| | - Margriet A Huisman
- Hair Science Institute, Maastricht, Maastricht, the Netherlands.,Department of Otorhinolaryngology and Head & Neck Surgery, Leiden University Medical Center, Leiden, the Netherlands
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36
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Ravindranathan A, Cimini B, Diolaiti ME, Stohr BA. Preliminary development of an assay for detection of TERT expression, telomere length, and telomere elongation in single cells. PLoS One 2018; 13:e0206525. [PMID: 30517099 PMCID: PMC6281304 DOI: 10.1371/journal.pone.0206525] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 10/15/2018] [Indexed: 02/06/2023] Open
Abstract
The telomerase enzyme enables unlimited proliferation of most human cancer cells by elongating telomeres and preventing replicative senescence. Despite the critical importance of telomerase in cancer biology, challenges detecting telomerase activity and expression in individual cells have hindered the ability to study patterns of telomerase expression and function across heterogeneous cell populations. While sensitive assays to ascertain telomerase expression and function exist, these approaches have proven difficult to implement at the single cell level. Here, we validate in situ RNAscope detection of the telomerase TERT mRNA and couple this assay with our recently described TSQ1 method for in situ detection of telomere elongation. This approach enables detection of TERT expression, telomere length, and telomere elongation within individual cells of the population. Using this assay, we show that the heterogeneous telomere elongation observed across a HeLa cell population is in part driven by variable expression of the TERT gene. Furthermore, we show that the absence of detectable telomere elongation in some TERT-positive cells is the result of inhibition by the telomeric shelterin complex. This combined assay provides a new approach for understanding the integrated expression, function, and regulation of telomerase at the single cell level.
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Affiliation(s)
- Ajay Ravindranathan
- Department of Pathology, University of California, San Francisco, California, United States of America
| | - Beth Cimini
- Department of Biochemistry and Biophysics, University of California, San Francisco, California, United States of America
| | - Morgan E Diolaiti
- Department of Pathology, University of California, San Francisco, California, United States of America
| | - Bradley A Stohr
- Department of Pathology, University of California, San Francisco, California, United States of America
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37
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Nickens DG, Rogers CM, Bochman ML. The Saccharomyces cerevisiae Hrq1 and Pif1 DNA helicases synergistically modulate telomerase activity in vitro. J Biol Chem 2018; 293:14481-14496. [PMID: 30068549 DOI: 10.1074/jbc.ra118.004092] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 07/23/2018] [Indexed: 11/06/2022] Open
Abstract
Telomere length homeostasis is vital for maintaining genomic stability and is regulated by multiple factors, including telomerase activity and DNA helicases. The Saccharomyces cerevisiae Pif1 helicase was the first discovered catalytic inhibitor of telomerase, but recent experimental evidence suggests that Hrq1, the yeast homolog of the disease-linked human RecQ-like helicase 4 (RECQL4), plays a similar role via an undefined mechanism. Using yeast extracts enriched for telomerase activity and an in vitro primer extension assay, here we determined the effects of recombinant WT and inactive Hrq1 and Pif1 on total telomerase activity and telomerase processivity. We found that titrations of these helicases alone have equal-but-opposite biphasic effects on telomerase, with Hrq1 stimulating activity at high concentrations. When the helicases were combined in reactions, however, they synergistically inhibited or stimulated telomerase activity depending on which helicase was catalytically active. These results suggest that Hrq1 and Pif1 interact and that their concerted activities ensure proper telomere length homeostasis in vivo We propose a model in which Hrq1 and Pif1 cooperatively contribute to telomere length homeostasis in yeast.
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Affiliation(s)
- David G Nickens
- From the Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana 47405
| | - Cody M Rogers
- From the Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana 47405
| | - Matthew L Bochman
- From the Molecular and Cellular Biochemistry Department, Indiana University, Bloomington, Indiana 47405
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38
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Spåhr H, Chia T, Lingford JP, Siira SJ, Cohen SB, Filipovska A, Rackham O. Modular ssDNA binding and inhibition of telomerase activity by designer PPR proteins. Nat Commun 2018; 9:2212. [PMID: 29880855 PMCID: PMC5992170 DOI: 10.1038/s41467-018-04388-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/25/2018] [Indexed: 02/06/2023] Open
Abstract
DNA is typically found as a double helix, however it must be separated into single strands during all phases of DNA metabolism; including transcription, replication, recombination and repair. Although recent breakthroughs have enabled the design of modular RNA- and double-stranded DNA-binding proteins, there are currently no tools available to manipulate single-stranded DNA (ssDNA). Here we show that artificial pentatricopeptide repeat (PPR) proteins can be programmed for sequence-specific ssDNA binding. Interactions occur using the same code and specificity as for RNA binding. We solve the structures of DNA-bound and apo proteins revealing the basis for ssDNA binding and how hydrogen bond rearrangements enable the PPR structure to envelope its ssDNA target. Finally, we show that engineered PPRs can be designed to bind telomeric ssDNA and can block telomerase activity. The modular mode of ssDNA binding by PPR proteins provides tools to target ssDNA and to understand its importance in cells. Pentatricopeptide repeat proteins bind single-stranded RNA and have been used to study ssRNA biology. Here the authors co-opt these proteins to target ssDNA and demonstrate specific binding of telomere sequences, the structural basis for ssDNA wrapping, and use them as potent telomerase inhibitors.
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Affiliation(s)
- Henrik Spåhr
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, D-50931, Cologne, Germany
| | - Tiongsun Chia
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - James P Lingford
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Stefan J Siira
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Scott B Cohen
- Children's Medical Research Institute, University of Sydney, 214 Hawkesbury Road, Westmead, NSW, 2145, Australia
| | - Aleksandra Filipovska
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, 6009, Australia.,School of Molecular Sciences, The University of Western Australia, Crawley, WA, 6009, Australia
| | - Oliver Rackham
- Harry Perkins Institute of Medical Research and Centre for Medical Research, The University of Western Australia, Nedlands, WA, 6009, Australia. .,School of Molecular Sciences, The University of Western Australia, Crawley, WA, 6009, Australia.
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39
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How long does telomerase extend telomeres? Regulation of telomerase release and telomere length homeostasis. Curr Genet 2018; 64:1177-1181. [PMID: 29663033 PMCID: PMC6223848 DOI: 10.1007/s00294-018-0836-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 04/09/2018] [Accepted: 04/09/2018] [Indexed: 01/28/2023]
Abstract
Telomerase, the enzyme that replenishes telomeres, is essential for most eukaryotes to maintain their generations. Telomere length homeostasis is achieved via a balance between telomere lengthening by telomerase, and erosion over successive cell divisions. Impaired telomerase regulation leads to shortened telomeres and can cause defects in tissue maintenance. Telomeric DNA is composed of a repetitive sequence, which recruits the protective protein complex, shelterin. Shelterin, together with chromatin remodelling proteins, shapes the heterochromatic structure at the telomere and protects chromosome ends. Shelterin also provides a foothold for telomerase to be recruited and facilitates telomere extension. Such mechanisms of telomere recruitment and activation are conserved from unicellular eukaryotes to humans, with the rate of telomere extension playing an important role in determining the length maintained. Telomerase can be processive, adding multiple telomeric repeats before dissociating. However, a question remains: how does telomerase determine the number of repeats to add? In this review, I will discuss about how telomerase can monitor telomere extension using fission yeast as a model. I propose a model whereby the accumulation of the Pot1 complex on the synthesised telomere single-strand counteracts retention of telomerase via chromatin proteins and the similar system may be conserved in mammals.
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40
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Scahill CM, Digby Z, Sealy IM, White RJ, Wali N, Collins JE, Stemple DL, Busch-Nentwich EM. The age of heterozygous telomerase mutant parents influences the adult phenotype of their offspring irrespective of genotype in zebrafish. Wellcome Open Res 2018; 2:77. [PMID: 29568807 PMCID: PMC5840683 DOI: 10.12688/wellcomeopenres.12530.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2017] [Indexed: 12/03/2022] Open
Abstract
Background: Mutations in proteins involved in telomere maintenance lead to a range of human diseases, including dyskeratosis congenita, idiopathic pulmonary fibrosis and cancer. Telomerase functions to add telomeric repeats back onto the ends of chromosomes, however non-canonical roles of components of telomerase have recently been suggested. Methods: Here we use a zebrafish telomerase mutant which harbours a nonsense mutation in
tert to investigate the adult phenotypes of fish derived from heterozygous parents of different ages. Furthermore we use whole genome sequencing data to estimate average telomere lengths. Results: We show that homozygous offspring from older heterozygotes exhibit signs of body wasting at a younger age than those of younger parents, and that offspring of older heterozygous parents weigh less irrespective of genotype. We also demonstrate that
tert homozygous mutant fish have a male sex bias, and that clutches from older parents also have a male sex bias in the heterozygous and wild-type populations. Telomere length analysis reveals that the telomeres of younger heterozygous parents are shorter than those of older heterozygous parents. Conclusions: These data indicate that the phenotypes observed in offspring from older parents cannot be explained by telomere length. Instead we propose that Tert functions outside of telomere length maintenance in an age-dependent manner to influence the adult phenotypes of the next generation.
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Affiliation(s)
| | - Zsofia Digby
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK.,Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Ian M Sealy
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Richard J White
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Neha Wali
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - John E Collins
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Derek L Stemple
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK
| | - Elisabeth M Busch-Nentwich
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, UK.,Department of Medicine, University of Cambridge, Cambridge, UK
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41
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Collopy LC, Ware TL, Goncalves T, Í Kongsstovu S, Yang Q, Amelina H, Pinder C, Alenazi A, Moiseeva V, Pearson SR, Armstrong CA, Tomita K. LARP7 family proteins have conserved function in telomerase assembly. Nat Commun 2018; 9:557. [PMID: 29422501 PMCID: PMC5805788 DOI: 10.1038/s41467-017-02296-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 11/20/2017] [Indexed: 11/15/2022] Open
Abstract
Understanding the intricacies of telomerase regulation is crucial due to the potential health benefits of modifying its activity. Telomerase is composed of an RNA component and reverse transcriptase. However, additional factors required during biogenesis vary between species. Here we have identified fission yeast Lar7 as a member of the conserved LARP7 family, which includes the Tetrahymena telomerase-binding protein p65 and human LARP7. We show that Lar7 has conserved RNA-recognition motifs, which bind telomerase RNA to protect it from exosomal degradation. In addition, Lar7 is required to stabilise the association of telomerase RNA with the protective complex LSm2–8, and telomerase reverse transcriptase. Lar7 remains a component of the mature telomerase complex and is required for telomerase localisation to the telomere. Collectively, we demonstrate that Lar7 is a crucial player in fission yeast telomerase biogenesis, similarly to p65 in Tetrahymena, and highlight the LARP7 family as a conserved factor in telomere maintenance. The telomerase holoenzyme is minimally composed of the reverse transcriptase and the RNA template. Here the authors identify Lar7 as a member of the full complex that helps to stabilise it and protect telomerase RNA from degradation.
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Affiliation(s)
- Laura C Collopy
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK
| | - Tracy L Ware
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK.,Department of Biology, Salem State University, Salem, MA, 01970, USA
| | - Tomas Goncalves
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK.,Division of Biosciences, Faculty of Life Sciences, University College London, London, WC1E 6BT, UK
| | - Sunnvør Í Kongsstovu
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK.,MSc Human Molecular Genetics, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - Qian Yang
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK
| | - Hanna Amelina
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK
| | - Corinne Pinder
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK.,Division of Biosciences, Faculty of Life Sciences, University College London, London, WC1E 6BT, UK
| | - Ala Alenazi
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK.,MSc Human Molecular Genetics, Faculty of Medicine, Imperial College London, London, SW7 2AZ, UK
| | - Vera Moiseeva
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK
| | - Siân R Pearson
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK
| | - Christine A Armstrong
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK
| | - Kazunori Tomita
- Chromosome Maintenance Group, UCL Cancer Institute, University College London, London, WC1E 6DD, UK.
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Telomeres: Implications for Cancer Development. Int J Mol Sci 2018; 19:ijms19010294. [PMID: 29351238 PMCID: PMC5796239 DOI: 10.3390/ijms19010294] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 01/12/2018] [Accepted: 01/16/2018] [Indexed: 12/31/2022] Open
Abstract
Telomeres facilitate the protection of natural ends of chromosomes from constitutive exposure to the DNA damage response (DDR). This is most likely achieved by a lariat structure that hides the linear telomeric DNA through protein-protein and protein-DNA interactions. The telomere shortening associated with DNA replication in the absence of a compensatory mechanism culminates in unmasked telomeres. Then, the subsequent activation of the DDR will define the fate of cells according to the functionality of cell cycle checkpoints. Dysfunctional telomeres can suppress cancer development by engaging replicative senescence or apoptotic pathways, but they can also promote tumour initiation. Studies in telomere dynamics and karyotype analysis underpin telomere crisis as a key event driving genomic instability. Significant attainment of telomerase or alternative lengthening of telomeres (ALT)-pathway to maintain telomere length may be permissive and required for clonal evolution of genomically-unstable cells during progression to malignancy. We summarise current knowledge of the role of telomeres in the maintenance of chromosomal stability and carcinogenesis.
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43
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Maguire D, Neytchev O, Talwar D, McMillan D, Shiels PG. Telomere Homeostasis: Interplay with Magnesium. Int J Mol Sci 2018; 19:E157. [PMID: 29303978 PMCID: PMC5796106 DOI: 10.3390/ijms19010157] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 12/21/2017] [Accepted: 01/03/2018] [Indexed: 12/14/2022] Open
Abstract
Telomere biology, a key component of the hallmarks of ageing, offers insight into dysregulation of normative ageing processes that accompany age-related diseases such as cancer. Telomere homeostasis is tightly linked to cellular metabolism, and in particular with mitochondrial physiology, which is also diminished during cellular senescence and normative physiological ageing. Inherent in the biochemistry of these processes is the role of magnesium, one of the main cellular ions and an essential cofactor in all reactions that use ATP. Magnesium plays an important role in many of the processes involved in regulating telomere structure, integrity and function. This review explores the mechanisms that maintain telomere structure and function, their influence on circadian rhythms and their impact on health and age-related disease. The pervasive role of magnesium in telomere homeostasis is also highlighted.
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Affiliation(s)
- Donogh Maguire
- Emergency Medicine Department, Glasgow Royal Infirmary, Glasgow G4 0SF, UK.
- Academic Unit of Surgery, School of Medicine, University of Glasgow, Glasgow Royal Infirmary, Glasgow G4 0SF, UK.
| | - Ognian Neytchev
- Section of Epigenetics, Institute of Cancer Sciences, University of Glasgow, Glasgow G61 1QH, UK.
| | - Dinesh Talwar
- The Scottish Trace Element and Micronutrient Reference Laboratory, Department of Biochemistry, Royal Infirmary, Glasgow G31 2ER, UK.
| | - Donald McMillan
- Academic Unit of Surgery, School of Medicine, University of Glasgow, Glasgow Royal Infirmary, Glasgow G4 0SF, UK.
| | - Paul G Shiels
- Section of Epigenetics, Institute of Cancer Sciences, University of Glasgow, Glasgow G61 1QH, UK.
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44
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Wang Y, Feigon J. Structural biology of telomerase and its interaction at telomeres. Curr Opin Struct Biol 2017; 47:77-87. [PMID: 28732250 PMCID: PMC5564310 DOI: 10.1016/j.sbi.2017.06.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 06/29/2017] [Indexed: 12/21/2022]
Abstract
Telomerase is an RNP that synthesizes the 3' ends of linear chromosomes and is an important regulator of telomere length. It contains a single long non-coding telomerase RNA (TER), telomerase reverse transcriptase (TERT), and other proteins that vary among organisms. Recent progress in structural biology of telomerase includes reports of the first cryo-electron microscopy structure of telomerase, from Tetrahymena, new crystal structures of TERT domains, telomerase RNA structures and models, and identification in Tetrahymena telomerase holoenzyme of human homologues of telomere-associated proteins that have provided a more unified view of telomerase interaction at telomeres as well as insights into the role of telomerase RNA in activity and assembly.
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Affiliation(s)
- Yaqiang Wang
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095-1569, USA
| | - Juli Feigon
- Department of Chemistry and Biochemistry, University of California Los Angeles, Los Angeles, CA 90095-1569, USA.
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45
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Ibáñez-Cabellos JS, Pérez-Machado G, Seco-Cervera M, Berenguer-Pascual E, García-Giménez JL, Pallardó FV. Acute telomerase components depletion triggers oxidative stress as an early event previous to telomeric shortening. Redox Biol 2017; 14:398-408. [PMID: 29055871 PMCID: PMC5650655 DOI: 10.1016/j.redox.2017.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 10/04/2017] [Accepted: 10/05/2017] [Indexed: 01/13/2023] Open
Abstract
Loss of function of dyskerin (DKC1), NOP10 and TIN2 are responsible for different inheritance patterns of Dyskeratosis congenita (DC; ORPHA1775). They are key components of telomerase (DKC1 and NOP10) and shelterin (TIN2), and play an important role in telomere homeostasis. They participate in several fundamental cellular processes by contributing to Dyskeratosis congenita through mechanisms that are not fully understood. Presence of oxidative stress was postulated to result from telomerase ablation. However, the resulting disturbed redox status can promote telomere attrition by generating a vicious circle, which promotes cellular senescence. This fact prompted us to study if acute loss of DKC1, NOP10 and TINF2 can promote redox disequilibrium as an early event when telomere shortening has not yet taken place. We generated siRNA-mediated (DKC1, NOP10 and TINF2) cell lines by RNA interference, which was confirmed by mRNA and protein expression analyses. No telomere shortening occurred in any silenced cell line. Depletion of H/ACA ribonucleoproteins DKC1 and NOP10 diminished telomerase activity via TERC down-regulation, and produced alterations in pseudouridylation and ribosomal biogenesis. An increase in the GSSG/GSH ratio, carbonylated proteins and oxidized peroxiredoxin-6 was observed, in addition to MnSOD and TRX1 overexpression in the siRNA DC cells. Likewise, high PARylation levels and high PARP1 protein expression were detected. In contrast, the silenced TINF2 cells did not alter any evaluated oxidative stress marker. Altogether these findings lead us to conclude that loss of DKC1 and NOP10 functions induces oxidative stress in a telomere shortening independent manner. Transient silencing of DKC1 and NOP10 genes produce oxidative stress. Cells depleted of DKC1 and NOP10 are susceptible to DNA damage. Acute DKC1 and NOP10 depletion disrupts RNA maturation. Oxidative stress is an early event previous to telomere shortening.
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Affiliation(s)
- José Santiago Ibáñez-Cabellos
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Institute of Health Carlos III, Valencia, Spain; Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain; INCLIVA Biomedical Research Institute, Valencia, Spain.
| | - Giselle Pérez-Machado
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain; INCLIVA Biomedical Research Institute, Valencia, Spain.
| | - Marta Seco-Cervera
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Institute of Health Carlos III, Valencia, Spain; Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain; INCLIVA Biomedical Research Institute, Valencia, Spain.
| | - Ester Berenguer-Pascual
- Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain.
| | - José Luis García-Giménez
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Institute of Health Carlos III, Valencia, Spain; Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain; INCLIVA Biomedical Research Institute, Valencia, Spain.
| | - Federico V Pallardó
- Center for Biomedical Network Research on Rare Diseases (CIBERER), Institute of Health Carlos III, Valencia, Spain; Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia, Spain; INCLIVA Biomedical Research Institute, Valencia, Spain.
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46
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Scahill CM, Digby Z, Sealy IM, White RJ, Collins JE, Busch-Nentwich EM. The age of heterozygous telomerase mutant parents influences the adult phenotype of their offspring irrespective of genotype in zebrafish. Wellcome Open Res 2017. [DOI: 10.12688/wellcomeopenres.12530.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Background: Mutations in proteins involved in telomere maintenance lead to a range of human diseases, including dyskeratosis congenita, idiopathic pulmonary fibrosis and cancer. Telomerase functions to add telomeric repeats back onto the ends of chromosomes, however non-canonical roles of components of telomerase have recently been suggested.Methods: Here we use a zebrafish telomerase mutant which harbours a nonsense mutation intertto investigate the adult phenotypes of fish derived from heterozygous parents of different ages. Furthermore we use whole genome sequencing data to estimate average telomere lengths.Results: We show that homozygous offspring from older heterozygotes exhibit signs of body wasting at a younger age than those of younger parents, and that offspring of older heterozygous parents weigh less irrespective of genotype. We also demonstrate thatterthomozygous mutant fish have a male sex bias, and that clutches from older parents also have a male sex bias in the heterozygous and wild-type populations. Telomere length analysis reveals that the telomeres of younger heterozygous parents are shorter than those of older heterozygous parents.Conclusions: These data indicate that the phenotypes observed in offspring from older parents cannot be explained by telomere length. Instead we propose that Tert functions outside of telomere length maintenance in an age-dependent manner to influence the adult phenotypes of the next generation.
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47
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Balc'h EL, Grandin N, Demattei MV, Guyétant S, Tallet A, Pagès JC, Ouaissi M, Lecomte T, Charbonneau M. Measurement of Telomere Length in Colorectal Cancers for Improved Molecular Diagnosis. Int J Mol Sci 2017; 18:ijms18091871. [PMID: 28850092 PMCID: PMC5618520 DOI: 10.3390/ijms18091871] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/18/2017] [Accepted: 08/25/2017] [Indexed: 02/06/2023] Open
Abstract
All tumors have in common to reactivate a telomere maintenance mechanism to allow for unlimited proliferation. On the other hand, genetic instability found in some tumors can result from the loss of telomeres. Here, we measured telomere length in colorectal cancers (CRCs) using TRF (Telomere Restriction Fragment) analysis. Telomeric DNA content was also quantified as the ratio of total telomeric (TTAGGG) sequences over that of the invariable Alu sequences. In most of the 125 CRCs analyzed, there was a significant diminution in telomere length compared with that in control healthy tissue. Only 34 tumors exhibited no telomere erosion and, in some cases, a slight telomere lengthening. Telomere length did not correlate with age, gender, tumor stage, tumor localization or stage of tumor differentiation. In addition, while telomere length did not correlate with the presence of a mutation in BRAF (V-raf murine sarcoma viral oncogene homolog B), PIK3CA (phosphatidylinositol 3-kinase catalytic subunit), or MSI status, it was significantly associated with the occurrence of a mutation in KRAS. Interestingly, we found that the shorter the telomeres in healthy tissue of a patient, the larger an increase in telomere length in the tumor. Our study points to the existence of two types of CRCs based on telomere length and reveals that telomere length in healthy tissue might influence telomere maintenance mechanisms in the tumor.
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Affiliation(s)
- Eric Le Balc'h
- CHRU Hôpital de Tours Trousseau, avenue de la République, 37170 Chambray-lès-Tours, France.
| | - Nathalie Grandin
- UMR CNRS 7292, UFR Pharmacy, University of Tours, Parc Grandmont, 31 avenue Monge, 37200 Tours, France.
| | - Marie-Véronique Demattei
- UMR CNRS 7292, UFR Pharmacy, University of Tours, Parc Grandmont, 31 avenue Monge, 37200 Tours, France.
| | - Serge Guyétant
- CHRU Hôpital de Tours Trousseau, avenue de la République, 37170 Chambray-lès-Tours, France.
| | - Anne Tallet
- CHRU Hôpital de Tours Trousseau, avenue de la République, 37170 Chambray-lès-Tours, France.
| | - Jean-Christophe Pagès
- CHRU Hôpital de Tours Trousseau, avenue de la République, 37170 Chambray-lès-Tours, France.
| | - Mehdi Ouaissi
- CHRU Hôpital de Tours Trousseau, avenue de la République, 37170 Chambray-lès-Tours, France.
| | - Thierry Lecomte
- CHRU Hôpital de Tours Trousseau, avenue de la République, 37170 Chambray-lès-Tours, France.
- UMR CNRS 7292, UFR Pharmacy, University of Tours, Parc Grandmont, 31 avenue Monge, 37200 Tours, France.
| | - Michel Charbonneau
- UMR CNRS 7292, UFR Pharmacy, University of Tours, Parc Grandmont, 31 avenue Monge, 37200 Tours, France.
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de Almeida AJPO, Ribeiro TP, de Medeiros IA. Aging: Molecular Pathways and Implications on the Cardiovascular System. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:7941563. [PMID: 28874954 PMCID: PMC5569936 DOI: 10.1155/2017/7941563] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 06/27/2017] [Indexed: 02/06/2023]
Abstract
The world's population over 60 years is growing rapidly, reaching 22% of the global population in the next decades. Despite the increase in global longevity, individual healthspan needs to follow this growth. Several diseases have their prevalence increased by age, such as cardiovascular diseases, the leading cause of morbidity and mortality worldwide. Understanding the aging biology mechanisms is fundamental to the pursuit of cardiovascular health. In this way, aging is characterized by a gradual decline in physiological functions, involving the increased number in senescent cells into the body. Several pathways lead to senescence, including oxidative stress and persistent inflammation, as well as energy failure such as mitochondrial dysfunction and deregulated autophagy, being ROS, AMPK, SIRTs, mTOR, IGF-1, and p53 key regulators of the metabolic control, connecting aging to the pathways which drive towards diseases. In addition, senescence can be induced by cellular replication, which resulted from telomere shortening. Taken together, it is possible to draw a common pathway unifying aging to cardiovascular diseases, and the central point of this process, senescence, can be the target for new therapies, which may result in the healthspan matching the lifespan.
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Affiliation(s)
- Arthur José Pontes Oliveira de Almeida
- Departamento de Ciências Farmacêuticas/Centro de Ciências da Saúde, Universidade Federal da Paraíba, Cidade Universitária-Campus I, Caixa Postal 5009, 58.051-970 João Pessoa, PB, Brazil
| | - Thaís Porto Ribeiro
- Departamento de Ciências Farmacêuticas/Centro de Ciências da Saúde, Universidade Federal da Paraíba, Cidade Universitária-Campus I, Caixa Postal 5009, 58.051-970 João Pessoa, PB, Brazil
| | - Isac Almeida de Medeiros
- Departamento de Ciências Farmacêuticas/Centro de Ciências da Saúde, Universidade Federal da Paraíba, Cidade Universitária-Campus I, Caixa Postal 5009, 58.051-970 João Pessoa, PB, Brazil
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Erlendson AA, Friedman S, Freitag M. A Matter of Scale and Dimensions: Chromatin of Chromosome Landmarks in the Fungi. Microbiol Spectr 2017; 5:10.1128/microbiolspec.FUNK-0054-2017. [PMID: 28752814 PMCID: PMC5536859 DOI: 10.1128/microbiolspec.funk-0054-2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Indexed: 02/06/2023] Open
Abstract
Chromatin and chromosomes of fungi are highly diverse and dynamic, even within species. Much of what we know about histone modification enzymes, RNA interference, DNA methylation, and cell cycle control was first addressed in Saccharomyces cerevisiae, Schizosaccharomyces pombe, Aspergillus nidulans, and Neurospora crassa. Here, we examine the three landmark regions that are required for maintenance of stable chromosomes and their faithful inheritance, namely, origins of DNA replication, telomeres and centromeres. We summarize the state of recent chromatin research that explains what is required for normal function of these specialized chromosomal regions in different fungi, with an emphasis on the silencing mechanism associated with subtelomeric regions, initiated by sirtuin histone deacetylases and histone H3 lysine 27 (H3K27) methyltransferases. We explore mechanisms for the appearance of "accessory" or "conditionally dispensable" chromosomes and contrast what has been learned from studies on genome-wide chromosome conformation capture in S. cerevisiae, S. pombe, N. crassa, and Trichoderma reesei. While most of the current knowledge is based on work in a handful of genetically and biochemically tractable model organisms, we suggest where major knowledge gaps remain to be closed. Fungi will continue to serve as facile organisms to uncover the basic processes of life because they make excellent model organisms for genetics, biochemistry, cell biology, and evolutionary biology.
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Affiliation(s)
- Allyson A. Erlendson
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331
| | - Steven Friedman
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331
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