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1.
Nat Commun ; 11(1): 4766, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32958778

RESUMO

Germline telomere maintenance defects are associated with an increased incidence of inflammatory diseases in humans, yet whether and how telomere dysfunction causes inflammation are not known. Here, we show that telomere dysfunction drives pATM/c-ABL-mediated activation of the YAP1 transcription factor, up-regulating the major pro-inflammatory factor, pro-IL-18. The colonic microbiome stimulates cytosolic receptors activating caspase-1 which cleaves pro-IL-18 into mature IL-18, leading to recruitment of interferon (IFN)-γ-secreting T cells and intestinal inflammation. Correspondingly, patients with germline telomere maintenance defects exhibit DNA damage (γH2AX) signaling together with elevated YAP1 and IL-18 expression. In mice with telomere dysfunction, telomerase reactivation in the intestinal epithelium or pharmacological inhibition of ATM, YAP1, or caspase-1 as well as antibiotic treatment, dramatically reduces IL-18 and intestinal inflammation. Thus, telomere dysfunction-induced activation of the ATM-YAP1-pro-IL-18 pathway in epithelium is a key instigator of tissue inflammation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Ciclo Celular/metabolismo , Inflamação/patologia , Telômero/patologia , Proteínas Adaptadoras de Transdução de Sinal/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Antibacterianos/uso terapêutico , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Caspase 1/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/genética , Criança , Colo/metabolismo , Colo/microbiologia , Colo/patologia , Gastroenteropatias/patologia , Microbioma Gastrointestinal/efeitos dos fármacos , Microbioma Gastrointestinal/fisiologia , Humanos , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/microbiologia , Interleucina-18/genética , Interleucina-18/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Camundongos , Camundongos Mutantes , Fosforilação , Precursores de Proteínas/genética , Precursores de Proteínas/metabolismo , Transdução de Sinais , Telomerase/genética , Telomerase/metabolismo
2.
Brain Tumor Pathol ; 37(4): 154-158, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32749624

RESUMO

Telomerase reverse transcriptase promoter (TERTp) hotspot mutations are the most frequent mutations in primary glioblastomas (GBM). Previous studies have shown that the combination of TERTp and isocitrate dehydrogenase (IDH) status may serve as a useful diagnostic marker for oligodendroglioma and glioblastoma. In oligodendrogliomas, TERTp and IDH mutations, along with the 1p/19q codeletion, usually coexist and are likely to be founder mutations. However, in contrast to oligodendroglioma, the role of the TERTp status in GBM remains obscure. Here, we used Sanger sequencing, pyrosequencing, and digital PCR (dPCR) to examine the TERTp status in 15 pairs of frozen tissue samples from primary and recurrent IDH wild-type GBM, all of which were operated in a single institute. We showed that the TERTp status was stable between primary and recurrent GBM but this consistency was only detected by dPCR. The results suggest that dPCR is a powerful, highly sensitive tool to detect TERTp mutations, especially in a mixed cell population (e.g., a recurrent GBM tissue) where earlier treatment may have grossly altered the tumor microenvironment.


Assuntos
Neoplasias Encefálicas/genética , Análise Mutacional de DNA/métodos , Glioblastoma/genética , Mutação , Recidiva Local de Neoplasia/genética , Reação em Cadeia da Polimerase/métodos , Regiões Promotoras Genéticas/genética , Telomerase/genética , Humanos , Isocitrato Desidrogenase/genética , Sensibilidade e Especificidade
3.
Nat Commun ; 11(1): 3368, 2020 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-32632093

RESUMO

Blood pressure (BP) was inconsistently associated with migraine and the mechanisms of BP-lowering medications in migraine prophylaxis are unknown. Leveraging large-scale summary statistics for migraine (Ncases/Ncontrols = 59,674/316,078) and BP (N = 757,601), we find positive genetic correlations of migraine with diastolic BP (DBP, rg = 0.11, P = 3.56 × 10-06) and systolic BP (SBP, rg = 0.06, P = 0.01), but not pulse pressure (PP, rg = -0.01, P = 0.75). Cross-trait meta-analysis reveals 14 shared loci (P ≤ 5 × 10-08), nine of which replicate (P < 0.05) in the UK Biobank. Five shared loci (ITGB5, SMG6, ADRA2B, ANKDD1B, and KIAA0040) are reinforced in gene-level analysis and highlight potential mechanisms involving vascular development, endothelial function and calcium homeostasis. Mendelian randomization reveals stronger instrumental estimates of DBP (OR [95% CI] = 1.20 [1.15-1.25]/10 mmHg; P = 5.57 × 10-25) on migraine than SBP (1.05 [1.03-1.07]/10 mmHg; P = 2.60 × 10-07) and a corresponding opposite effect for PP (0.92 [0.88-0.95]/10 mmHg; P = 3.65 × 10-07). These findings support a critical role of DBP in migraine susceptibility and shared biology underlying BP and migraine.


Assuntos
Pressão Sanguínea/genética , Predisposição Genética para Doença/genética , Estudo de Associação Genômica Ampla/métodos , Metanálise como Assunto , Transtornos de Enxaqueca/genética , Polimorfismo de Nucleotídeo Único , Humanos , Hipertensão/genética , Cadeias beta de Integrinas/genética , Análise da Randomização Mendeliana/métodos , Proteínas/genética , Receptores Adrenérgicos alfa 2/genética , Fatores de Risco , Telomerase/genética
4.
Life Sci ; 257: 118055, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32634429

RESUMO

AIMS: Human adipose derived mesenchymal stem cells (hAD-MSCs) as the most promising target for cell therapy and regenerative medicine, face senescence as a major drawback resulting in their limited proliferation and differentiation potentials. To evaluate the efficacy of miR-34a silencing as an anti-senescence strategy in hAD-MSCs, in this study common hallmarks of senescence were assessed after transient inhibition of miR-34a in hAD-MSCs. MATERIALS AND METHODS: The expression levels of miR-34a in hAD-MSCs at different passages were evaluated by real-time quantitative PCR. hAD-MSCs at passage 2 and passage 7 were transfected with miR-34a inhibitor. Doubling time assay, colony forming assay, and cell cycle analysis were performed to evaluate cell proliferation rate. The activity of senescence associated ß-galactosidase (SA-ß-gal) was assessed by histochemical staining. Moreover, the senescence associated molecular alterations including that of pro-senescence (P53, P21 and P16) and anti-senescence (SIRT1, HTERT and CD44) genes were examined by quantitative RT-PCR and western blot assays. To evaluate the differentiation potentials of MSCs, following adipogenic and osteogenic induction, the expression levels of lineage specific markers were analyzed by qPCR. KEY FINDINGS: Our results showed that inhibition of miR-34a enhances the proliferation, promotes the adipogenic and osteogenic differentiation potency, reduces the senescence associated-ß gal activity, and reverses the senescence associated molecular alterations in hAD-MSCs. SIGNIFICANCE: In this study, we showed that inhibition of miR-34a reduces the cellular senescence through the activation of SIRT1. Our findings support the silencing of miR-34a as an anti-senescence approach to improve the therapeutic potentials of hAD-MSCs.


Assuntos
Diferenciação Celular/fisiologia , Senescência Celular/fisiologia , Células-Tronco Mesenquimais/citologia , MicroRNAs/genética , Sirtuína 1/genética , Adipogenia/fisiologia , Tecido Adiposo/citologia , Inativação Gênica , Humanos , Receptores de Hialuronatos/genética , Osteogênese/fisiologia , Telomerase/genética
5.
Arterioscler Thromb Vasc Biol ; 40(9): 2244-2264, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32640900

RESUMO

OBJECTIVE: Nanog is expressed in adult endothelial cells (ECs) at a low-level, however, its functional significance is not known. The goal of our study was to elucidate the role of Nanog in adult ECs using a genetically engineered mouse model system. Approach and Results: Biochemical analyses showed that Nanog is expressed in both adult human and mouse tissues. Primary ECs isolated from adult mice showed detectable levels of Nanog, Tert (telomerase reverse transcriptase), and eNos (endothelial nitric oxide synthase). Wnt3a (Wnt family member 3A) increased the expression of Nanog and hTERT (human telomerase reverse transcriptase) in ECs and increased telomerase activity in these cells. In a chromatin immunoprecipitation experiment, Nanog directly bound to the hTERT and eNOS promoter/enhancer DNA elements, thereby regulating their transcription. Administration of low-dose tamoxifen to ROSAmT/mG::Nanogfl/+::Cdh5CreERT2 mice induced deletion of a single Nanog allele, simultaneously labeling ECs with green fluorescent protein and resulting in decreased Tert and eNos levels. Histological and morphometric analyses of heart tissue sections prepared from these mice revealed cell death, microvascular rarefaction, and increased fibrosis in cardiac vessels. Accordingly, EC-specific Nanog-haploinsufficiency resulted in impaired EC homeostasis and angiogenesis. Conversely, re-expression of cDNA encoding the hTERT in Nanog-depleted ECs, in part, restored the effect of loss of Nanog. CONCLUSIONS: We showed that low-level Nanog expression is required for normal EC homeostasis and angiogenesis in adulthood.


Assuntos
Proliferação de Células , Senescência Celular , Vasos Coronários/metabolismo , Células Endoteliais/metabolismo , Endotélio Vascular/metabolismo , Proteína Homeobox Nanog/metabolismo , Animais , Apoptose , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Senescência Celular/efeitos dos fármacos , Vasos Coronários/efeitos dos fármacos , Vasos Coronários/patologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/patologia , Endotélio Vascular/efeitos dos fármacos , Endotélio Vascular/patologia , Feminino , Fibrose , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína Homeobox Nanog/deficiência , Proteína Homeobox Nanog/genética , Neovascularização Fisiológica , Óxido Nítrico Sintase Tipo III/genética , Óxido Nítrico Sintase Tipo III/metabolismo , Telomerase/genética , Telomerase/metabolismo , Ativação Transcricional , Via de Sinalização Wnt , Proteína Wnt3A/farmacologia
6.
Mutat Res ; 854-855: 503197, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32660821

RESUMO

Telomeres, specialized structures at the ends of linear chromosomes, protect chromosome ends from degradation, recombination, and mis-repair. Critically short telomere length (TL) may result in chromosome instability (CIN), causing tumor promotion and, at higher levels, cell death and tumor suppression. Homocysteine (Hcy) is a sulfur-containing amino acid involved in one-carbon metabolism. Elevated plasma Hcy is a cancer risk factor. Human SH-SY5Y neuroblastoma cells were treated with pathophysiological concentrations of Hcy (15-120 µM) for 14 and 28 days. The cytokinesis-block micronucleus cytome assay was used to determine cytostasis (nuclear division index, NDI), cell death (apoptosis and necrosis), and CIN (micronuclei, nucleoplasmic bridges, and nuclear buds in binucleated cells). Quantitative PCR was used to measure TL and the expression of hTERT, the gene encoding the catalytic subunit of telomerase for TL elongation. The results showed that Hcy induced elongation of TL and fluctuating changes in expression of hTERT. TL elongation was associated with increased CIN. Hcy decreased the NDI and increased cell death. This study shows that there is cross-talk between Hcy and TL in tumor cells and supports the concept that high Hcy inhibits cell division and promotes the death of tumor cells by abnormal elongation of TL and elevation of CIN.


Assuntos
Instabilidade Cromossômica/genética , Homocisteína/genética , Neuroblastoma/genética , Telômero/genética , Apoptose/genética , Morte Celular/genética , Divisão Celular/genética , Linhagem Celular Tumoral , Citocinese/genética , Dano ao DNA/genética , Humanos , Micronúcleos com Defeito Cromossômico , Testes para Micronúcleos/métodos , Necrose/genética , Telomerase/genética
7.
Nucleic Acids Res ; 48(13): 7239-7251, 2020 07 27.
Artigo em Inglês | MEDLINE | ID: mdl-32542379

RESUMO

Telomeres cap the ends of eukaryotic chromosomes and distinguish them from broken DNA ends to suppress DNA damage response, cell cycle arrest and genomic instability. Telomeres are elongated by telomerase to compensate for incomplete replication and nuclease degradation and to extend the proliferation potential of germ and stem cells and most cancers. However, telomeres in somatic cells gradually shorten with age, ultimately leading to cellular senescence. Hoyeraal-Hreidarsson syndrome (HHS) is characterized by accelerated telomere shortening and diverse symptoms including bone marrow failure, immunodeficiency, and neurodevelopmental defects. HHS is caused by germline mutations in telomerase subunits, factors essential for its biogenesis and recruitment to telomeres, and in the helicase RTEL1. While diverse phenotypes were associated with RTEL1 deficiency, the telomeric role of RTEL1 affected in HHS is yet unknown. Inducible ectopic expression of wild-type RTEL1 in patient fibroblasts rescued the cells, enabled telomerase-dependent telomere elongation and suppressed the abnormal cellular phenotypes, while silencing its expression resulted in gradual telomere shortening. Our observations reveal an essential role of the RTEL1 C-terminus in facilitating telomerase action at the telomeric 3' overhang. Thus, the common etiology for HHS is the compromised telomerase action, resulting in telomere shortening and reduced lifespan of telomerase positive cells.


Assuntos
DNA Helicases/metabolismo , Disceratose Congênita/genética , Retardo do Crescimento Fetal/genética , Deficiência Intelectual/genética , Microcefalia/genética , Homeostase do Telômero , Células Cultivadas , DNA Helicases/química , DNA Helicases/genética , Fibroblastos/metabolismo , Humanos , Domínios Proteicos , Telomerase/genética , Telomerase/metabolismo , Encurtamento do Telômero
8.
PLoS One ; 15(6): e0234002, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32497071

RESUMO

Human primary hepatocytes (PHs) are critical to studying liver functions, drug metabolism and toxicity. PHs isolated from livers that are unacceptable for transplantation have limited expansion and culture viability in vitro, in addition to rapidly deteriorating enzymatic functions. The unsuitability of immortalized hepato-carcinoma cell lines for this function has prompted studies to develop hepatocyte-like cells from alternative sources like ESC, iPS, and other stem cell types using differentiation protocols. This study describes a novel technique to produce expandable and functional hepatocyte-like cells from the fusion of an immortalized human umbilical cord blood derived cell line (E12 MLPC) to normal human primary hepatocytes. Multi-lineage progenitor cells (MLPC) comprise a small subset of mesenchymal-like cells isolated from human umbilical cord blood. MLPC are distinguishable from other mesenchymal-like cells by their extended expansion capacity (up to 80 cell doublings before senescence) and the ability to be differentiated into cells representative of endo-, meso- and ectodermal origins. Transfection of MLPC with the gene for telomerase reverse transcriptase (TERT) resulted in clonal cell lines that were capable of differentiation to different cellular outcomes while maintaining their functional immortality. A methodology for the development of immortalized hepatocyte-like hybrid cells by the in vitro fusion of human MLPC with normal human primary hepatocytes is reported. The resultant hybrid cells exhibited homology with hepatocytes by morphology, immunohistochemistry, urea and albumin production and gene expression. A medium that allows stable long-term expansion of hepatocyte-like fusion cells is described.


Assuntos
Fusão Celular , Hepatócitos/citologia , Células Híbridas/citologia , Células-Tronco/citologia , Diferenciação Celular , Células Cultivadas , Hepatócitos/metabolismo , Humanos , Células Híbridas/metabolismo , Células-Tronco/metabolismo , Telomerase/genética , Transfecção
9.
Proc Natl Acad Sci U S A ; 117(27): 15846-15851, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32561648

RESUMO

Combination use of BRAF V600E inhibitor dabrafenib and MEK inhibitor trametinib has become a standard treatment for human cancers harboring BRAF V600E. Its anticancer efficacies vary, however, with dramatic efficacy in some patients and drug resistance/tumor recurrence in others, which is poorly understood. Using thyroid cancer, melanoma, and colon cancer cell models, we showed that dabrafenib and trametinib induced robust apoptosis of cancer cells harboring both BRAF V600E and TERT promoter mutations but had little proapoptotic effect in cells harboring only BRAF V600E. Correspondingly, the inhibitors nearly completely abolished the growth of in vivo tumors harboring both mutations but had little effect on tumors harboring only BRAF V600E. Upon drug withdrawal, tumors harboring both mutations remained hardly measurable but tumors harboring only BRAF V600E regrew rapidly. BRAF V600E/MAP kinase pathway is known to robustly activate mutant promoter of TERT, a strong apoptosis suppressor. Thus, for survival, cancer cells harboring both mutations may have evolved to rely on BRAF V600E-promoted and high-TERT expression-mediated suppression of apoptosis. As such, inhibition of BRAF/MEK can trigger strong apoptosis-induced cell death and hence tumor abolishment. This does not happen in cells harboring only BRAF V600E as they have not developed reliance on TERT-mediated suppression of apoptosis due to the lack of mutant promoter-driven high-TERT expression. TERT promoter mutation governs BRAF-mutant cancer cells' apoptotic and hence therapeutic responses to BRAF/MEK inhibitors. Thus, the genetic duet of BRAF V600E and TERT promoter mutation represents an Achilles Heel for effective therapeutic targeting and response prediction in cancer.


Assuntos
Apoptose/efeitos dos fármacos , Mutação , Regiões Promotoras Genéticas/efeitos dos fármacos , Regiões Promotoras Genéticas/genética , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/efeitos dos fármacos , Proteínas Proto-Oncogênicas B-raf/genética , Telomerase/genética , Animais , Morte Celular , Linhagem Celular Tumoral , Neoplasias do Colo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Feminino , Humanos , Imidazóis/farmacologia , Melanoma/genética , Camundongos Nus , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Oximas/farmacologia , Piridonas/farmacologia , Pirimidinonas/farmacologia , Neoplasias da Glândula Tireoide/genética , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Mol Cell ; 79(1): 115-126.e6, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32497497

RESUMO

Extension of telomeres is a critical step in the immortalization of cancer cells. This complex reaction requires proper spatiotemporal coordination of telomerase and telomeres and remains poorly understood at the cellular level. To understand how cancer cells execute this process, we combine CRISPR genome editing and MS2 RNA tagging to image single molecules of telomerase RNA (hTR). Real-time dynamics and photoactivation experiments of hTR in Cajal bodies (CBs) reveal that hTERT controls the exit of hTR from CBs. Single-molecule tracking of hTR at telomeres shows that TPP1-mediated recruitment results in short telomere-telomerase scanning interactions, and then base pairing between hTR and telomere ssDNA promotes long interactions required for stable telomerase retention. Interestingly, POT1 OB-fold mutations that result in abnormally long telomeres in cancers act by enhancing this retention step. In summary, single-molecule imaging unveils the life cycle of telomerase RNA and provides a framework to reveal how cancer-associated mutations mechanistically drive defects in telomere homeostasis.


Assuntos
Corpos Enovelados/metabolismo , DNA de Cadeia Simples/metabolismo , RNA/metabolismo , Imagem Individual de Molécula/métodos , Telomerase/metabolismo , Homeostase do Telômero , Telômero/metabolismo , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , DNA de Cadeia Simples/genética , Edição de Genes , Células HeLa , Humanos , Mutação , RNA/genética , Telomerase/genética , Telômero/genética , Proteínas de Ligação a Telômeros/genética , Proteínas de Ligação a Telômeros/metabolismo
11.
APMIS ; 128(9): 515-522, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32580246

RESUMO

Peripheral nerve sheath tumors may occur sporadically or related to neurofibromatosis (NF). Unless the mechanisms of tumorigenesis in NF related malignant peripheral nerve sheath tumors (MPNST) are better understood, it remained unclear in sporadic cases. We aimed to investigate the genetic route for malignancy in both individuals with NF-1 and sporadic ones to open a way for targeted therapies in the future. We investigated the role of HER2 with Dual ISH DNA Probe Cocktail test, BRAF mutation (exon 15) and TERT promoter mutation frequency with Sanger sequencing method in respectively 25 sporadic neurofibromas, 25 NF-1 related neurofibromas and 25 MPNST cases from two institutes. Categorical data were analyzed and summarized as frequency and percentage. Statistical analysis was done with SPSS v.22 statistical package, and the statistical significance level was considered as 0.05. We identified TERT promoter mutation only in one sporadic MPNST (4%) and no BRAF mutation in any case. HER2 amplification is found in 10/25 (40%) MPNST cases. No mutations or gene amplification detected in neurofibromas (p < 0.001). MPNSTs are sarcomas with poor prognosis and limited treatment options. TERT promoter mutations and HER2 amplification may play a putative role in therapeutic purposes.


Assuntos
Neurofibromatose 1/genética , Neurofibrossarcoma/genética , Proteínas Proto-Oncogênicas B-raf/genética , Receptor ErbB-2/genética , Telomerase/genética , Adolescente , Adulto , Idoso , Criança , Feminino , Amplificação de Genes , Humanos , Masculino , Pessoa de Meia-Idade , Mutação , Neurofibroma/genética , Regiões Promotoras Genéticas , Adulto Jovem
12.
Cancer Sci ; 111(9): 3089-3099, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32579791

RESUMO

The telomere is the specialized nucleoprotein complex at the end of the chromosome. Its highly conserved 5'-TTAGGG-3' repeats and shelterin protein complexes form a protective loop structure to maintain the integrity and stability of linear chromosomes. Although human somatic cells gradually shorten telomeres to undergo senescence or crisis, cancer cells activate telomerase, or the recombination-based mechanism to maintain telomeres and exhibit immortality. As the most frequent non-coding mutations in cancer, gain-of-function mutations in the promoter region of the telomerase catalytic subunit, TERT, trigger telomerase activation. Promoter methylation and copy number gain are also associated with the enhanced TERT expression. Although telomerase inhibitors were pioneered from telomere-directed therapeutics, their efficacies are limited to cancer with short telomeres and some hematological malignancies. Other therapeutic approaches include a nucleoside analog incorporated to telomeres and TERT promoter-driven oncolytic adenoviruses. Tankyrase poly(ADP-ribose) polymerase, a positive regulator of telomerase, has been rediscovered as a target for Wnt-driven cancer. Meanwhile, telomeric nucleic acids form a higher-order structure called a G-quadruplex (G4). G4s are formed genome-wide and their dynamics affect various events, including replication, transcription, and translation. G4-stabilizing compounds (G4 ligands) exert anticancer effects and are in clinical investigations. Collectively, telomere biology has provided clues for deeper understanding of cancer, which expands opportunities to discover innovative anticancer drugs.


Assuntos
Antineoplásicos/farmacologia , Descoberta de Drogas , Telômero/efeitos dos fármacos , Animais , Antineoplásicos/uso terapêutico , Transformação Celular Neoplásica/genética , Quadruplex G/efeitos dos fármacos , Terapia Genética , Humanos , Ligantes , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/patologia , Terapia Viral Oncolítica , Regiões Promotoras Genéticas , RNA não Traduzido/genética , Telomerase/genética , Telomerase/metabolismo , Telômero/genética , Encurtamento do Telômero/efeitos dos fármacos
13.
Proc Natl Acad Sci U S A ; 117(26): 15066-15074, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32554492

RESUMO

Cancer incidence increases exponentially with age when human telomeres are shorter. Similarly, telomerase reverse transcriptase (tert) mutant zebrafish have premature short telomeres and anticipate cancer incidence to younger ages. However, because short telomeres constitute a road block to cell proliferation, telomere shortening is currently viewed as a tumor suppressor mechanism and should protect from cancer. This conundrum is not fully understood. In our current study, we report that telomere shortening promotes cancer in a noncell autonomous manner. Using zebrafish chimeras, we show increased incidence of invasive melanoma when wild-type (WT) tumors are generated in tert mutant zebrafish. Tissues adjacent to melanoma lesions (skin) and distant organs (intestine) in tert mutants exhibited higher levels of senescence and inflammation. In addition, we transferred second generation (G2) tert blastula cells into WT to produce embryo chimeras. Cells with very short telomeres induced increased tumor necrosis factor1-α (TNF1-α) expression and senescence in larval tissues in a noncell autonomous manner, creating an inflammatory environment. Considering that inflammation is protumorigenic, we transplanted melanoma-derived cells into G2 tert zebrafish embryos and observed that tissue environment with short telomeres leads to increased tumor development. To test if inflammation was necessary for this effect, we treated melanoma transplants with nonsteroid anti-inflammatory drugs and show that higher melanoma dissemination can be averted. Thus, apart from the cell autonomous role of short telomeres in contributing to genome instability, we propose that telomere shortening with age causes systemic chronic inflammation leading to increased tumor incidence.


Assuntos
Melanoma/metabolismo , Telômero/metabolismo , Peixe-Zebra/metabolismo , Animais , Modelos Animais de Doenças , Humanos , Melanoma/genética , Melanoma/imunologia , Telomerase/genética , Telomerase/metabolismo , Telômero/genética , Encurtamento do Telômero , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia , Peixe-Zebra/genética , Peixe-Zebra/imunologia , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
14.
Medicine (Baltimore) ; 99(23): e20551, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32502020

RESUMO

This study aimed to further understand the role of relative telomere length (RTL) in susceptibility to gastric carcinoma (GC) and investigate the association between genetic polymorphisms in the telomere length related genes and GC risk.RTL was measured using the real-time quantitative polymerase chain reaction from 1000 patients and 1100 healthy controls. Genotyping was performed using the Agena MassARRAY platform. The statistical analysis was performed using the chi-square/ Welch T tests, Mann-Whitney U test, and logistic regression analysis.The association analysis of telomere length and GC showed that the RTL in the case group was shorter than in the controls, and the shorter RTL was associated with an increased risk of GC. The association analysis between telomere length related genes polymorphisms and genetic susceptibility to GC indicated that: In the allele models and genetic models, TERT (rs10069690, rs2242652 and rs2853676) and TN1F1 (rs7708392 and rs10036748) were significantly associated with an increased risk of GC. In addition, the haplotype 'Grs10069690Crs2242652" of TERT and the haplotype 'Grs7708392Trs10036748" of TNIP1 were associated with an increased risk of GCOur results suggested that shorter RTL was associated with an increased risk of GC; The association analysis have identified that the TERT (rs10069690, rs2242652 and rs2853676) and TN1P1 (rs7708392 and rs10036748) were associated with GC risk.


Assuntos
Proteínas de Ligação a DNA/genética , Predisposição Genética para Doença , Neoplasias Gástricas/genética , Telomerase/genética , Telômero/genética , Estudos de Casos e Controles , China/epidemiologia , Feminino , Haplótipos , Humanos , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Reação em Cadeia da Polimerase em Tempo Real , Homeostase do Telômero
15.
Mol Biol (Mosk) ; 54(2): 308-312, 2020.
Artigo em Russo | MEDLINE | ID: mdl-32392201

RESUMO

A synthetic genetic chain was created-a two-promoter integrator, the activity of the output signal of which is high only with the high activity of two promoters at the input of the chain. The integrator is shown to work by the example of cancer-specific promoters of the human survivin and telomerase genes that can be used for specific transcription of target genes in tumor cells. To create the integrator, we used the well-known TET-ON 3G transactivator, regulated by doxycycline.


Assuntos
Doxiciclina/farmacologia , Regiões Promotoras Genéticas , Transativadores , Humanos , Survivina/genética , Telomerase/genética , Tetraciclina
16.
Nature ; 582(7810): 100-103, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32461694

RESUMO

Cancers develop as a result of driver mutations1,2 that lead to clonal outgrowth and the evolution of disease3,4. The discovery and functional characterization of individual driver mutations are central aims of cancer research, and have elucidated myriad phenotypes5 and therapeutic vulnerabilities6. However, the serial genetic evolution of mutant cancer genes7,8 and the allelic context in which they arise is poorly understood in both common and rare cancer genes and tumour types. Here we find that nearly one in four human tumours contains a composite mutation of a cancer-associated gene, defined as two or more nonsynonymous somatic mutations in the same gene and tumour. Composite mutations are enriched in specific genes, have an elevated rate of use of less-common hotspot mutations acquired in a chronology driven in part by oncogenic fitness, and arise in an allelic configuration that reflects context-specific selective pressures. cis-acting composite mutations are hypermorphic in some genes in which dosage effects predominate (such as TERT), whereas they lead to selection of function in other genes (such as TP53). Collectively, composite mutations are driver alterations that arise from context- and allele-specific selective pressures that are dependent in part on gene and mutation function, and which lead to complex-often neomorphic-functions of biological and therapeutic importance.


Assuntos
Carcinogênese/genética , Modelos Genéticos , Mutação , Neoplasias/genética , Oncogenes/genética , Alelos , Animais , Feminino , Genes p53/genética , Humanos , Camundongos , Seleção Genética , Telomerase/genética
17.
Artigo em Inglês | MEDLINE | ID: mdl-32404253

RESUMO

OBJECTIVE: The aim of the present study was to assess the prevalence of TERT promoter region mutations in tumor samples of patients with squamous cell carcinoma at different sites of the head and neck region and correlate it with patients' clinicopathologic data. STUDY DESIGN: Mutations in promoter region of the TERT gene were analyzed with polymerase chain reaction-based direct sequencing method using formalin-fixed, paraffin-embedded tumor samples of 189 HNSCCs. TERT promoter region mutations were assessed in terms of age, gender, location, smoking, alcohol consumption, and overall survival. RESULTS: TERT promoter region mutations were detected in the oral cavity (75%); larynx (8.4%), hypopharynx (16.6%), and oropharynx (0%). TERT promoter region mutations are associated with younger age and female gender and have a reverse relationship with smoking and alcohol consumption. CONCLUSIONS: We found statistically significant higher rates of TERT promoter region mutations in tumor samples of patients with squamous cell carcinoma in the oral cavity compared with other locations in the head and neck region.


Assuntos
Neoplasias de Cabeça e Pescoço , Carcinoma de Células Escamosas de Cabeça e Pescoço , Telomerase/genética , Feminino , Humanos , Mutação , Regiões Promotoras Genéticas
18.
Nat Commun ; 11(1): 2173, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-32358529

RESUMO

RNase P and MRP are highly conserved, multi-protein/RNA complexes with essential roles in processing ribosomal and tRNAs. Three proteins found in both complexes, Pop1, Pop6, and Pop7 are also telomerase-associated. Here, we determine how temperature sensitive POP1 and POP6 alleles affect yeast telomerase. At permissive temperatures, mutant Pop1/6 have little or no effect on cell growth, global protein levels, the abundance of Est1 and Est2 (telomerase proteins), and the processing of TLC1 (telomerase RNA). However, in pop mutants, TLC1 is more abundant, telomeres are short, and TLC1 accumulates in the cytoplasm. Although Est1/2 binding to TLC1 occurs at normal levels, Est1 (and hence Est3) binding is highly unstable. We propose that Pop-mediated stabilization of Est1 binding to TLC1 is a pre-requisite for formation and nuclear localization of the telomerase holoenzyme. Furthermore, Pop proteins affect TLC1 and the RNA subunits of RNase P/MRP in very different ways.


Assuntos
Ribonuclease P/metabolismo , Ribonucleoproteínas/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Telomerase/metabolismo , Telômero/metabolismo , Núcleo Celular/genética , Núcleo Celular/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Metilação , Ligação Proteica , RNA/metabolismo , Processamento de Terminações 3' de RNA/genética , Ribonuclease P/genética , Ribonucleoproteínas/genética , Proteínas de Saccharomyces cerevisiae/genética , Telomerase/genética , Telômero/química
19.
Brain Tumor Pathol ; 37(2): 33-40, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32227259

RESUMO

According to the 2016 World Health Organization (WHO) classification of central nervous system tumors, diffuse astrocytic and oligodendroglial tumors are differentiated by the presence of isocitrate dehydrogenase 1 or 2 (IDH1/2) mutation and the combined loss of the short arm of chromosome 1 and the long arm of chromosome 19 (1p/19q co-deletion). IDH-mutant astrocytoma often has p53 and alpha-thalassemia/mental retardation syndrome X-linked (ATRX) mutation, showing the alternative lengthening of telomeres (ALT) phenotype, while IDH-mutant and 1p/19q-co-deleted oligodendroglioma often have wild-type p53 and telomerase reverse transcriptase (TERT) promoter mutation, showing telomerase activation. This study analyzed IDH, ATRX, and TERT promoter mutations, and the correlation between them. Immortalized cells overcome the telomere-related crisis by activating telomerase or ALT. In glioma, telomerase is mainly activated by TERT promoter mutation, while ALT is usually associated with ATRX mutation. Although the mechanism of how ATRX mutation induces ALT remains unclear, ATRX loss alone is believed to be insufficient to induce ALT. Treatments targeting telomere maintenance are promising.


Assuntos
Neoplasias Encefálicas/genética , Glioma/genética , Isocitrato Desidrogenase/genética , Mutação , Telomerase/genética , Proteína Nuclear Ligada ao X/genética , Ativação Enzimática/genética , Estudos de Associação Genética , Humanos , Regiões Promotoras Genéticas , Telomerase/metabolismo
20.
Georgian Med News ; (299): 75-78, 2020 Feb.
Artigo em Russo | MEDLINE | ID: mdl-32242849

RESUMO

The clinical studies, conducted in recent years, suggest that statins increase the activity of telomerase and by that decelerate speed of telomerase shortening. Thus, on one hand, it reduces a risk of cardiovascular diseases development, decelerate aging, but on the other hand, increasing the activity of telomerase, lead to expression rising of gene hTERT, that can make prerequisites for malignancy. That's why, it's necessary to study the subject and develop reliable criteria for safety use of activators-telomerase.


Assuntos
Inibidores de Hidroximetilglutaril-CoA Redutases/efeitos adversos , Telomerase/metabolismo , Telômero/efeitos dos fármacos , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Telomerase/genética , Telômero/metabolismo , Encurtamento do Telômero/efeitos dos fármacos
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