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1.
Int J Oral Sci ; 12(1): 3, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31911577

RESUMO

High-risk human papillomaviruses (HPVs) are involved in the development of several human cancers, including oropharyngeal squamous cell carcinomas. However, many studies have demonstrated that HPV alone is not sufficient for the oncogenic transformation of normal human epithelial cells, indicating that additional cofactors are required for the oncogenic conversion of HPV-infected cells. Inasmuch as chronic inflammation is also closely associated with carcinogenesis, we investigated the effect of chronic exposure to tumor necrosis factor α (TNFα), the major proinflammatory cytokine, on oncogenesis in two immortalized oral keratinocyte cell lines, namely, HPV16-immortalized and human telomerase reverse transcriptase (hTERT)-immortalized cells. TNFα treatment led to the acquisition of malignant growth properties in HPV16-immortalized cells, such as (1) calcium resistance, (2) anchorage independence, and (3) increased cell proliferation in vivo. Moreover, TNFα increased the cancer stem cell-like population and stemness phenotype in HPV16-immortalized cells. However, such transforming effects were not observed in hTERT-immortalized cells, suggesting an HPV-specific role in TNFα-promoted oncogenesis. We also generated hTERT-immortalized cells that express HPV16 E6 and E7. Chronic TNFα exposure successfully induced the malignant growth and stemness phenotype in the E6-expressing cells but not in the control and E7-expressing cells. We further demonstrated that HPV16 E6 played a key role in TNFα-induced cancer stemness via suppression of the stemness-inhibiting microRNAs miR-203 and miR-200c. Overexpression of miR-203 and miR-200c suppressed cancer stemness in TNFα-treated HPV16-immortalized cells. Overall, our study suggests that chronic inflammation promotes cancer stemness in HPV-infected cells, thereby promoting HPV-associated oral carcinogenesis.


Assuntos
Carcinoma de Células Escamosas/genética , Papillomavirus Humano 16/metabolismo , MicroRNAs/metabolismo , Neoplasias Bucais/genética , Boca/metabolismo , Proteínas Oncogênicas Virais/metabolismo , Infecções por Papillomavirus/virologia , Telomerase/genética , Fator de Necrose Tumoral alfa/metabolismo , Carcinogênese/genética , Carcinogênese/imunologia , Carcinoma de Células Escamosas/patologia , Transformação Celular Viral/genética , Regulação da Expressão Gênica , Genes Virais , Papillomavirus Humano 16/genética , Humanos , MicroRNAs/genética , Boca/virologia , Neoplasias Bucais/patologia , Proteínas Oncogênicas Virais/genética , Papillomaviridae/genética , Telomerase/metabolismo , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia
2.
Nat Commun ; 11(1): 160, 2020 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-31919430

RESUMO

The Nuclear Pore Complex (NPC) has emerged as an important hub for processing various types of DNA damage. Here, we uncover that fusing a DNA binding domain to the NPC basket protein Nup1 reduces telomere relocalization to nuclear pores early after telomerase inactivation. This Nup1 modification also impairs the relocalization to the NPC of expanded CAG/CTG triplet repeats. Strikingly, telomerase negative cells bypass senescence when expressing this Nup1 modification by maintaining a minimal telomere length compatible with proliferation through rampant unequal exchanges between sister chromatids. We further report that a Nup1 mutant lacking 36 C-terminal residues recapitulates the phenotypes of the Nup1-LexA fusion indicating a direct role of Nup1 in the relocation of stalled forks to NPCs and restriction of error-prone recombination between repeated sequences. Our results reveal a new mode of telomere maintenance that could shed light on how 20% of cancer cells are maintained without telomerase or ALT.


Assuntos
Senescência Celular/genética , Complexo de Proteínas Formadoras de Poros Nucleares/genética , Saccharomyces cerevisiae/genética , Troca de Cromátide Irmã/genética , Telômero/genética , Cromátides/metabolismo , Dano ao DNA/genética , Reparo do DNA/genética , Poro Nuclear/metabolismo , Telomerase/metabolismo
3.
J Cancer Res Clin Oncol ; 146(2): 381-389, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31960186

RESUMO

PURPOSE: To evaluate the prevalence of two recurrent somatic mutations (-124 C>T and -146 C>T) within the promoter of the gene encoding telomerase reverse transcriptase (TERT) as well as their relationship with TERT level, telomeres length, and outcome in patients with head and neck squamous cell carcinomas (HNSCCs). METHODS: We evaluate the prevalence of TERT promoter mutations, TERT levels, and telomere length in paired cancer tissue and adjacent mucosa (AM) in a series of HNSCCs. RESULTS: Cancer tissue and AM specimens from 105 patients were analyzed. Telomere length and TERT mRNA levels were estimated using real-time polymerase chain reaction. TERT promoter mutations were assessed using Sanger sequencing. Out of 105 cases, 101 were considered suitable for the analysis. TERT promoter harbored mutations in 12 tumors (11.9%), with -124 C>T and -146 C>T accounting for 83.3% and 16.7% of the alterations, respectively. No mutations were detected in AM samples. The prevalence of TERT promoter mutations was significantly higher in oral cavity SCCs (10 out of 27 tumors; 37%), and telomere length in AM was shorter in patients with tumors carrying TERT promoter mutations than in patients with unmutated TERT promoter cancers (p = 0.023). TERT levels in tumor did not significantly differ according to the mutational status of TERT promoter. No significant association was found between TERT promoter status and overall survival. CONCLUSION: TERT promoter mutations are most likely a late event in tumor development, occurring in a context of critically short telomeres, mostly in patients with oral cavity SCC. TERT levels, but not TERT promoter mutational status impact clinical outcome.


Assuntos
Neoplasias de Cabeça e Pescoço/genética , Mutação , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Telomerase/genética , Telômero/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Feminino , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Regiões Promotoras Genéticas , Estudos Prospectivos , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/patologia , Análise de Sobrevida , Telomerase/metabolismo , Telômero/genética , Telômero/patologia
5.
Life Sci ; 241: 117061, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31794774

RESUMO

The consumption of cruciferous vegetables rich in isothiocyanates has long been associated with a reduced risk of various types of cancer. 4-(methylthio)butyl isothiocyanate also called erucin is an isothiocyanate present in appreciable quantity in the seeds of Eruca sativa Mill. plant. Although the literature has revealed its protective effects via inducing phase II enzymes and inhibiting carcinogen activating phase I enzymes, recent studies also suggest that, it inhibits the proliferation of cancer cells by altering the telomerase activity, dynamics of microtubules, expression of histone deacetylases, and other molecular pathways. With this in mind, the emphasis has been made to review the molecular targets involved in cancer prevention by 4-(methylthio)butyl isothiocyanate.


Assuntos
Anticarcinógenos/farmacologia , Antineoplásicos/farmacologia , Isotiocianatos/farmacologia , Animais , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Humanos , Telomerase/metabolismo , Tubulina (Proteína)/metabolismo , Moduladores de Tubulina/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Cell Mol Life Sci ; 77(1): 61-79, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31728577

RESUMO

Telomeres are protein-DNA complexes that protect chromosome ends from illicit ligation and resection. Telomerase is a ribonucleoprotein enzyme that synthesizes telomeric DNA to counter telomere shortening. Human telomeres are composed of complexes between telomeric DNA and a six-protein complex known as shelterin. The shelterin proteins TRF1 and TRF2 provide the binding affinity and specificity for double-stranded telomeric DNA, while the POT1-TPP1 shelterin subcomplex coats the single-stranded telomeric G-rich overhang that is characteristic of all our chromosome ends. By capping chromosome ends, shelterin protects telomeric DNA from unwanted degradation and end-to-end fusion events. Structures of the human shelterin proteins reveal a network of constitutive and context-specific interactions. The shelterin protein-DNA structures reveal the basis for both the high affinity and DNA sequence specificity of these interactions, and explain how shelterin efficiently protects chromosome ends from genome instability. Several protein-protein interactions, many provided by the shelterin component TIN2, are critical for upholding the end-protection function of shelterin. A survey of these protein-protein interfaces within shelterin reveals a series of "domain-peptide" interactions that allow for efficient binding and adaptability towards new functions. While the modular nature of shelterin has facilitated its part-by-part structural characterization, the interdependence of subunits within telomerase has made its structural solution more challenging. However, the exploitation of several homologs in combination with recent advancements in cryo-EM capabilities has led to an exponential increase in our knowledge of the structural biology underlying telomerase function. Telomerase homologs from a wide range of eukaryotes show a typical retroviral reverse transcriptase-like protein core reinforced with elements that deliver telomerase-specific functions including recruitment to telomeres and high telomere-repeat addition processivity. In addition to providing the template for reverse transcription, the RNA component of telomerase provides a scaffold for the catalytic and accessory protein subunits, defines the limits of the telomeric repeat sequence, and plays a critical role in RNP assembly, stability, and trafficking. While a high-resolution definition of the human telomerase structure is only beginning to emerge, the quick pace of technical progress forecasts imminent breakthroughs in this area. Here, we review the structural biology surrounding telomeres and telomerase to provide a molecular description of mammalian chromosome end protection and end replication.


Assuntos
Telomerase/metabolismo , Proteínas de Ligação a Telômeros/metabolismo , Telômero/metabolismo , Aminopeptidases/química , Aminopeptidases/metabolismo , Animais , Cromossomos/química , Cromossomos/metabolismo , Dipeptidil Peptidases e Tripeptidil Peptidases/química , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Humanos , Modelos Moleculares , Conformação Proteica , Serina Proteases/química , Serina Proteases/metabolismo , Telomerase/química , Telômero/química , Proteínas de Ligação a Telômeros/química
7.
Dalton Trans ; 48(40): 15247-15254, 2019 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-31577283

RESUMO

Two novel Pt(ii) complexes, [Pt(B-TFA)Cl]Cl (Pt1) and [Pt(J-TFA)Cl]Cl (Pt2) with jatrorrhizine and berberine derivatives (B-TFA and J-TFA) were first prepared as desirable luminescent agents for cellular applications and potent telomerase inhibitors, which can induce bladder T-24 tumor cell apoptosis by targeting telomerase, together with induction of mitochondrial dysfunction, telomere DNA damage and cell-cycle arrest. Importantly, T-24 tumor inhibition rate (TIR) was 50.4% for Pt2, which was higher than that of Pt1 (26.4%) and cisplatin (37.1%). Taken together, all the results indicated that jatrorrhizine and berberine derivatives Pt1 and Pt2 show low toxicity and could be novel Pt-based anti-cancer drug candidates.


Assuntos
Antineoplásicos/farmacologia , Berberina/análogos & derivados , Berberina/farmacologia , Compostos Organoplatínicos/farmacologia , Telomerase/antagonistas & inibidores , Neoplasias da Bexiga Urinária/tratamento farmacológico , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Berberina/química , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Dano ao DNA , Humanos , Mitocôndrias/efeitos dos fármacos , Compostos Organoplatínicos/química , Telomerase/metabolismo
8.
Medicine (Baltimore) ; 98(43): e17578, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31651862

RESUMO

BACKGROUND: To evaluate the methylation levels of human telomerase reverse transcriptase (hTERT) promoter three CpG island (CGIs) regions and its prognostic impact in Chinese patients with acral and mucosal melanoma. METHODS: Bioinformatics software was used to analyze hTERT gene promoter. Fresh frozen tissues were taken from 14 patients with melanoma (6 acral melanoma and 8 mucosal melanoma) and 14 pigmented nevus as control subjects (14 acral pigmented nevus). Bisulfite sequencing PCR (BSP) combined TA clone sequencing was used to assess the methylation levels of hTERT promoter CGIs regions. The relative expression level of hTERT mRNA was measured by quantitative real-time polymerase chain reaction (qRT-PCR). RESULTS: CGIs-1 (-1392--1098 bp), CGIs-2 (-945--669 bp), and CGIs-3 (-445--48 bp) were selected for our study. Our results indicated that the methylation levels of hTERT promotor CGIs regions in melanoma were greater than pigmented nevus (CGIs-1: 69.3 ±â€Š18.7% vs 46.8 ±â€Š20.4%, t = 3.048 P = .005; CGIs-2: 73.8 ±â€Š14.7% vs 55.6 ±â€Š16.0%, t = 3.120 P = .004; CGIs-3: 5.8 ±â€Š2.2% vs 2.2 ±â€Š1.3%, t = 5.164 P < .001). The relative expression level of hTERT in melanoma was greater than in pigmented nevus (50.39 ±â€Š9.16 vs 26.10 ±â€Š7.25, t = 7.778, P < .001). Linear regression analysis showed that the methylation level of CGIs-2 in melanoma was positively correlated with the relative expression level of hTERT mRNA (R = .490, F = 13.478, P = .003). Combined with the analysis of clinicopathological features, the methylation level of CGIs-2 in melanoma with lymph node metastasis was greater than in melanoma without lymph node metastasis, and the methylation level of CGIs-2 increased with TNM staging. CONCLUSION: CGIs-2 methylation level was associated with the relative expression level of hTERT mRNA, lymph node metastasis and TNM staging, suggesting that CGIs-2 hypermethylation might be used to evaluate the prognosis in Chinese patients with acral and mucosal melanoma.


Assuntos
Ilhas de CpG/genética , Metilação de DNA/genética , Melanoma/genética , Proteína 2 de Ligação a Metil-CpG/metabolismo , Telomerase/metabolismo , Idoso , Grupo com Ancestrais do Continente Asiático/genética , China , Biologia Computacional , Feminino , Humanos , Modelos Lineares , Metástase Linfática , Masculino , Melanoma/mortalidade , Melanoma/patologia , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Reação em Cadeia da Polimerase , Prognóstico , RNA Mensageiro/metabolismo
9.
Int Rev Neurobiol ; 147: 121-153, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31607352

RESUMO

Chronic fatigue syndrome (CFS) is often overlooked, has unclear etiology and no effective cure except some symptomatic treatments. Additionally, most people with CFS do not seek medical attention. Qigong exercise, an ancient Eastern body-mind-spirit practice, has been long practiced in Chinese communities and may powerfully trigger the self-healing process. Using full baseline data (n=1409), the average Hong Kong CFS respondent was found to be female, married, 42.5yo, highly educated and employed full-time, experiencing sleep disturbance (~95%), anxiety (>80%), and depressive symptoms (68%). Here, we summarized our previous studies to evaluate the potential of Qigong as a complementary and alternative therapy for CFS. Two randomized controlled trials were conducted (RCT1 n1=137, RCT2 n2=150). In both trials, extensive online questionnaires allowed individuals with CFS-like illness (i.e., symptoms match CFS, yet without clinical confirmation) to be identified. RCT1 included a 5-week intervention. The intervention in RCT2 was 8weeks. In RCT1 Qigong group had reduced fatigue (P<0.001) and depressive symptoms (P=0.002), and improved telomerase activity (P=0.029). An effective practice regimen was identified (≥3 days/week, at ≥30min/session). Methods were slightly adjusted for RCT2, which replicated RCT1 findings, and further documented improved subjective sleep quality (P=0.008) and adiponectin levels (P<0.05). A significant dose-response relationship was founded. Thus, Qigong exercise should be recognized as a possible standalone therapy and self-management skill in CFS. Strategies are needed to increase motivation for regular practice and to explore its possibility of self-management skill in brain health. Further clarity would come from studies comparing Qigong with other physical exercises.


Assuntos
Síndrome de Fadiga Crônica/terapia , Qigong , Adiponectina/sangue , Adulto , Depressão/complicações , Depressão/terapia , Terapia por Exercício , Síndrome de Fadiga Crônica/sangue , Síndrome de Fadiga Crônica/complicações , Síndrome de Fadiga Crônica/metabolismo , Feminino , Humanos , Masculino , Projetos Piloto , Transtornos do Sono-Vigília/complicações , Transtornos do Sono-Vigília/terapia , Telomerase/metabolismo , Adulto Jovem
10.
Int J Mol Sci ; 20(19)2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31623314

RESUMO

We aimed to immortalize primarily isolated human deciduous tooth-derived dental pulp cells (HDDPCs) by transfection with piggyBac (PB)-based transposon vectors carrying E7 from human papilloma virus 16 or complementary DNA (cDNA) encoding human telomerase reverse transcriptase (hTERT). HDDPCs were co-transfected with pTrans (conferring PB transposase expression) + pT-pac (conferring puromycin acetyltransferase expression) + pT-tdTomato (conferring tdTomato cDNA expression) and pT-E7 (conferring E7 expression) or pTrans + pT-pac + pT-EGFP (conferring enhanced green fluorescent protein cDNA expression) + pT-hTERT (conferring hTERT expression). After six days, these cells were selected in medium containing 5 µg/mL puromycin for one day, and then cultured in normal medium allowing cell survival. All resultant colonies were harvested and propagated as a pool. Stemness and tumorigenic properties of the established cell lines ("MT_E7" for E7 and "MT_hTERT" for hTERT) with untransfected parental cells (MT) were examined. Both lines exhibited proliferation similar to that of MT, with alkaline phosphatase activity and stemness-specific factor expression. They displayed differentiation potential into multi-lineage cells with no tumorigenic property. Overall, we successfully obtained HDDPC-derived immortalized cell lines using a PB-based transfection system. The resultant and parental cells were indistinguishable. Thus, E7 and hTERT could immortalize HDDPCs without causing cancer-associated changes or altering phenotypic properties.


Assuntos
Diferenciação Celular , Elementos de DNA Transponíveis , Polpa Dentária/citologia , Células-Tronco/citologia , Células-Tronco/metabolismo , Diferenciação Celular/genética , Linhagem Celular Transformada , Transformação Celular Neoplásica , Feminino , Vetores Genéticos/genética , Humanos , Proteínas Oncogênicas Virais/genética , Células-Tronco/patologia , Telomerase/genética , Telomerase/metabolismo , Dente Decíduo , Transfecção
11.
Int J Mol Sci ; 20(18)2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31533313

RESUMO

Tumor angiogenesis research and antiangiogenic drug development make use of cultured endothelial cells (ECs) including the human microvascular ECs among others. However, it has been reported that tumor ECs (TECs) are different from normal ECs (NECs). To functionally validate antiangiogenic drugs, cultured TECs are indispensable tools, but are not commercially available. Primary human TECs are available only in small quantities from surgical specimens and have a short life span in vitro due to their cellular senescence. We established immortalized human TECs (h-imTECs) and their normal counterparts (h-imNECs) by infection with lentivirus producing simian virus 40 large T antigen and human telomerase reverse transcriptase to overcome the replication barriers. These ECs exhibited an extended life span and retained their characteristic endothelial morphology, expression of endothelial marker, and ability of tube formation. Furthermore, h-imTECs showed their specific characteristics as TECs, such as increased proliferation and upregulation of TEC markers. Treatment with bevacizumab, an antiangiogenic drug, dramatically decreased h-imTEC survival, whereas the same treatment failed to alter immortalized NEC survival. Hence, these h-imTECs could be a valuable tool for drug screening to develop novel therapeutic agents specific to TECs or functional biological assays in tumor angiogenesis research.


Assuntos
Transformação Celular Neoplásica , Células Endoteliais/metabolismo , Células Endoteliais/patologia , Neoplasias Renais/patologia , Antígenos Transformantes de Poliomavirus/genética , Antígenos Transformantes de Poliomavirus/metabolismo , Biomarcadores , Linhagem Celular Transformada , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Expressão Ectópica do Gene , Humanos , Cariotipagem , Telomerase/genética , Telomerase/metabolismo
12.
Molecules ; 24(17)2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31480619

RESUMO

Based on the structural scaffolds of natural products, two series of flavonoid derivatives, for a total of twelve compounds, were designed and synthesized as potential human telomerase inhibitors. Using a modified TRAP-PCR assay, compound 5c exhibited the most potent inhibitory activity against human telomerase with an IC50 value of less than 50 µM. In vitro, the results demonstrated that compound 5c had potent anticancer activity against five classes of tumor cell lines. The molecular docking and molecular dynamics analyses binding to the human telomerase holoenzyme were performed to elucidate the binding mode of active compound 5c. This finding helps the rational design of more potent telomerase inhibitors based on the structural scaffolds of natural products.


Assuntos
Desenho de Drogas , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/farmacologia , Flavonoides/síntese química , Flavonoides/farmacologia , Simulação de Acoplamento Molecular , Telomerase/antagonistas & inibidores , Sítios de Ligação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Inibidores Enzimáticos/química , Flavonoides/química , Humanos , Concentração Inibidora 50 , Ligantes , Telomerase/metabolismo
13.
Mol Med Rep ; 20(4): 3701-3708, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31485647

RESUMO

Telomere length, a marker of cellular aging, decreases with age and it has been associated with aging­related diseases. Environmental factors, including diet and lifestyle factors, affect the rate of telomere shortening which can be reversed by telomerase. Telomerase activation by natural molecules has been suggested to be an anti­aging modulator that can play a role in the treatment of aging­related diseases. This study aimed to investigate the effect of natural compounds on telomerase activity in human peripheral blood mononuclear cells (PBMCs). The tested compounds included Centella asiatica extract formulation (08AGTLF), Astragalus extract formulation (Nutrient 4), TA­65 (containing Astragalus membranaceus extract), oleanolic acid (OA), maslinic acid (MA), and 3 multi­nutrient formulas (Nutrients 1, 2 and 3) at various concentrations. The mean absorbance values of telomerase activity measured following treatment with some of the above­mentioned formulations were statistically significantly higher compared to those of the untreated cells. In particular, in order of importance with respect to telomerase activation from highest to lowest, 08AGTLF, OA, Nutrient 4, TA­65, MA, Nutrient 3 and Nutrient 2, triggered statistically significant increase in telomerase activity compared to the untreated cells. 08AGTLF reached the highest levels of telomerase activity reported to date, at least to our knowledge, increasing telomerase activity by 8.8 folds compared to untreated cells, while Nutrient 4 and OA were also potent activators (4.3­fold and 5.9­fold increase, respectively). On the whole, this study indicates that the synergistic effect of nutrients and natural compounds can activate telomerase and produce more potent formulations. Human clinical studies using these formulations are required to evaluate their mode of action. This would reveal the health benefits of telomerase activation through natural molecules and would shed new light onto the treatment of aging­related diseases.


Assuntos
Senescência Celular/efeitos dos fármacos , Ativadores de Enzimas/farmacologia , Leucócitos Mononucleares/efeitos dos fármacos , Extratos Vegetais/farmacologia , Telomerase/metabolismo , Astrágalo (Planta)/química , Células Cultivadas , Descoberta de Drogas , Humanos , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/metabolismo , Ácido Oleanólico/farmacologia , Encurtamento do Telômero/efeitos dos fármacos , Triterpenos/farmacologia
14.
Genes Dev ; 33(19-20): 1381-1396, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31488579

RESUMO

Short telomere syndromes manifest as familial idiopathic pulmonary fibrosis; they are the most common premature aging disorders. We used genome-wide linkage to identify heterozygous loss of function of ZCCHC8, a zinc-knuckle containing protein, as a cause of autosomal dominant pulmonary fibrosis. ZCCHC8 associated with TR and was required for telomerase function. In ZCCHC8 knockout cells and in mutation carriers, genomically extended telomerase RNA (TR) accumulated at the expense of mature TR, consistent with a role for ZCCHC8 in mediating TR 3' end targeting to the nuclear RNA exosome. We generated Zcchc8-null mice and found that heterozygotes, similar to human mutation carriers, had TR insufficiency but an otherwise preserved transcriptome. In contrast, Zcchc8-/- mice developed progressive and fatal neurodevelopmental pathology with features of a ciliopathy. The Zcchc8-/- brain transcriptome was highly dysregulated, showing accumulation and 3' end misprocessing of other low-abundance RNAs, including those encoding cilia components as well as the intronless replication-dependent histones. Our data identify a novel cause of human short telomere syndromes-familial pulmonary fibrosis and uncover nuclear exosome targeting as an essential 3' end maturation mechanism that vertebrate TR shares with replication-dependent histones.


Assuntos
Proteínas de Transporte/genética , Fibrose Pulmonar Idiopática/genética , Mutação com Perda de Função , Proteínas Nucleares/genética , RNA/metabolismo , Telomerase/metabolismo , Animais , Encéfalo/enzimologia , Encéfalo/fisiopatologia , Linhagem Celular , Cílios/genética , Feminino , Ligação Genética , Células HCT116 , Humanos , Fibrose Pulmonar Idiopática/enzimologia , Fibrose Pulmonar Idiopática/fisiopatologia , Masculino , Camundongos , Camundongos Knockout , Transtornos do Neurodesenvolvimento/genética , Linhagem , Processamento Pós-Transcricional do RNA/genética , Encurtamento do Telômero/genética
15.
Insect Biochem Mol Biol ; 115: 103241, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31536769

RESUMO

The attrition of telomeres, the ends of eukaryote chromosomes, and activity of telomerase, the enzyme that restores telomere length, play a role in the ageing process and act as indicators of biological age. A notable feature of advanced eusocial insects is the longevity of reproductive individuals (queens and kings) compared to those from non-reproductive castes (workers and soldiers) within a given species, with a proposed link towards upregulation of telomerase activity in the somatic tissues of reproductive individuals. Given this, eusocial insects provide excellent model systems for research into ageing. We tested telomerase activity and measured telomere length in Bombus terrestris, which is a primitively eusocial insect species with several distinct features compared to advanced social insects. In somatic tissues, telomerase activity was upregulated only in the fat bodies of pre-diapause queens, and this upregulation was linked to heightened DNA synthesis. Telomere length was shorter in old queens compared to that in younger queens or workers. We speculate that (1) the upregulation of telomerase activity, together with DNA synthesis, is the essential step for intensifying metabolic activity in the fat body to build up a sufficient energy reserve prior to diapause, and that (2) the lifespan differences between B. terrestris workers and queens are related to the long diapause period of the queen. A possible relationship between telomere length regulation and TOR, FOXO, and InR as cell signaling components, was tested.


Assuntos
Abelhas/enzimologia , Corpo Adiposo/enzimologia , Telomerase/metabolismo , Animais , DNA/biossíntese , Feminino , Encurtamento do Telômero
16.
Mol Cell Biol ; 39(21)2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31383750

RESUMO

TIN2 is an important regulator of telomere length, and mutations in TINF2, the gene encoding TIN2, cause short-telomere syndromes. While the genetics underscore the importance of TIN2, the mechanism through which TIN2 regulates telomere length remains unclear. Here, we tested the effects of human TIN2 on telomerase activity. We identified a new isoform in human cells, TIN2M, that is expressed at levels similar to those of previously studied TIN2 isoforms. All three TIN2 isoforms localized to and maintained telomere integrity in vivo, and localization was not disrupted by telomere syndrome mutations. Using direct telomerase activity assays, we discovered that TIN2 stimulated telomerase processivity in vitro All of the TIN2 isoforms stimulated telomerase to similar extents. Mutations in the TPP1 TEL patch abrogated this stimulation, suggesting that TIN2 functions with TPP1/POT1 to stimulate telomerase processivity. We conclude from our data and previously published work that TIN2/TPP1/POT1 is a functional shelterin subcomplex.


Assuntos
Aminopeptidases/metabolismo , Dipeptidil Peptidases e Tripeptidil Peptidases/metabolismo , Serina Proteases/metabolismo , Telomerase/metabolismo , Proteínas de Ligação a Telômeros/metabolismo , Telômero/metabolismo , Linhagem Celular Tumoral , Células HeLa , Humanos , Ligação Proteica , Isoformas de Proteínas
17.
Biosens Bioelectron ; 142: 111543, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31376711

RESUMO

Telomerase has been regarded as a biomarker for cancer diagnosis as well as the clinical treatment and the reliable detection of intracellular telomerase activity is of great significance. By developing a telomere elongation-based DNA-catalytic amplification strategy, a novel surface-enhanced Raman scattering (SERS) method is proposed for the assay of telomerase activity. In the presence of telomerase and nucleotide mixture dNTPs, the telomerase substrate (TS) primer extended and generated a long single-strand DNA (ssDNA) containing the telomere repeat units (TTAGGG)n, which could catalyze the entropy-driven circuit reaction (EDCR). One of the products of EDCR was ingeniously used as the catalyst of catalytic hairpin assembly (CHA) occured on magnetic beads (MBs). As a result, a large amount of ROX-labeled Raman probes could be anchored on the surface of MBs and used for SERS detection. Using this strategy, the assay can detect telomerase activity from cell extracts equivalent down to single HeLa cell.


Assuntos
Técnicas Biossensoriais/métodos , DNA Catalítico/metabolismo , Análise Espectral Raman/métodos , Telomerase/metabolismo , Linhagem Celular Tumoral , Avaliação Pré-Clínica de Medicamentos , Ensaios Enzimáticos/métodos , Humanos , Técnicas de Amplificação de Ácido Nucleico/métodos , Especificidade por Substrato , Telomerase/antagonistas & inibidores , Telômero/metabolismo
18.
Clin Interv Aging ; 14: 1343-1352, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31413555

RESUMO

Purpose: This study was aimed at determining the presence of cognitive frailty and its associated factors among community-dwelling older adults from the "LRGS-Towards Useful Aging (TUA)" longitudinal study. Patients and methods: The available data related to cognitive frailty among a sub-sample of older adults aged 60 years and above (n=815) from two states in Malaysia were analysed. In the LRGS-TUA study, a comprehensive interview-based questionnaire was administered to obtain the socio-demographic information of the participants, followed by assessments to examine the cognitive function, functional status, dietary intake, lifestyle, psychosocial status and biomarkers associated with cognitive frailty. The factors associated with cognitive frailty were assessed using a bivariate logistic regression (BLR). Results: The majority of the older adults were categorized as robust (68.4%), followed by cognitively pre-frail (37.4%) and cognitively frail (2.2%). The data on the cognitively frail and pre-frail groups were combined for comparison with the robust group. A hierarchical BLR indicated that advancing age (OR=1.04, 95% CI:1.01-1.08, p<0.05) and depression (OR=1.49, 95% CI:1.34-1.65, p<0.001) scored lower on the Activity of Daily Living (ADL) scale (OR=0.98, 95% CI:0.96-0.99, p<0.05), while low social support (OR=0.98, 95% CI:0.97-0.99, p<0.05) and low niacin intake (OR=0.94, 95% CI:0.89-0.99, p<0.05) were found to be significant factors for cognitive frailty. Higher oxidative stress (MDA) and lower telomerase activity were also associated with cognitive frailty (p<0.05). Conclusion: Older age, a lower niacin intake, lack of social support, depression and lower functional status were identified as significant factors associated with cognitive frailty among older Malaysian adults. MDA and telomerase activity can be used as potential biomarkers for the identification of cognitive frailty.


Assuntos
Disfunção Cognitiva/epidemiologia , Idoso Fragilizado/estatística & dados numéricos , Fragilidade/epidemiologia , Atividades Cotidianas , Idoso , Idoso de 80 Anos ou mais , Biomarcadores , Cognição , Estudos Transversais , Dieta , Feminino , Humanos , Vida Independente , Estilo de Vida , Modelos Logísticos , Estudos Longitudinais , Malásia/epidemiologia , Masculino , Saúde Mental , Pessoa de Meia-Idade , Niacina/sangue , Estresse Oxidativo/fisiologia , Desempenho Físico Funcional , Fatores Socioeconômicos , Telomerase/metabolismo
19.
Analyst ; 144(20): 5959-5964, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31441909

RESUMO

It is of great importance to achieve facile and reliable detection of telomerase because it is an important cancer biomarker. The complex components of cell extracts and ultra-low concentration of telomerase makes it more difficult to realize a simple and sensitive visual detection of telomerase activity. Herein, a facile and sensitive visual strategy was developed for the detection of telomerase based on the telomerase-controlled in situ formation of a G-quadruplex-hemin DNAzyme. To avoid the influence of the complex components of cell extracts, a telomerase substrate (TS) was immobilized onto the surface of magnetic beads (MBs) to form a MB/TS complex. MB/TS incubated with telomerase can add several TTAGGG repeat units to the 3' terminal of TS. After magnetic separation and washing, these G-rich elongated DNA folded into numerous G-quadruplex-hemin DNAzymes under the aid of K+ and hemin, which efficiently catalysed the TMB/H2O2 reaction. Magnetic separation basically eliminated the non-specific background interference from other cell extracts and redundant hemin. Taking full advantage of the in situ formation of multiple catalysts, the telomerase activity could be sensitively evaluated by a color change of the TMB/H2O2 solution. The telomerase activity down to 1 HeLa cell per µL and 0.5 HeLa cell per µL can be measured by the naked eye and UV-vis spectroscopy, respectively. Due to the magnetic separation and enrichment, the sensitivity was obviously improved compared with the previous colorimetric assay. Meanwhile, the telomerase activity of 5 HeLa cells per µL in human serum can be visually detected. Therefore, this study provides a facile, cost-effective and robust colorimetric assay for the visual detection of telomerase activity, which holds great potential in telomerase-based cancer clinical diagnostics.


Assuntos
Técnicas Biossensoriais/métodos , DNA Catalítico/química , Ensaios Enzimáticos/métodos , Quadruplex G , Hemina/química , Neoplasias/metabolismo , Telomerase/metabolismo , Colorimetria , Humanos , Neoplasias/diagnóstico , Células Tumorais Cultivadas
20.
Respir Res ; 20(1): 196, 2019 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-31443657

RESUMO

BACKGROUND: The pathology of chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF) and most lung cancers involves the small airway epithelium (SAE), the single continuous layer of cells lining the airways ≥ 6th generations. The basal cells (BC) are the stem/progenitor cells of the SAE, responsible for the differentiation into intermediate cells and ciliated, club and mucous cells. To facilitate the study of the biology of the human SAE in health and disease, we immortalized and characterized a normal human SAE basal cell line. METHODS: Small airway basal cells were purified from brushed SAE of a healthy nonsmoker donor with a characteristic normal SAE transcriptome. The BC were immortalized by retrovirus-mediated telomerase reverse transcriptase (TERT) transduction and single cell drug selection. The resulting cell line (hSABCi-NS1.1) was characterized by RNAseq, TaqMan PCR, protein immunofluorescence, differentiation capacity on an air-liquid interface (ALI) culture, transepithelial electrical resistance (TEER), airway region-associated features and response to genetic modification with SPDEF. RESULTS: The hSABCi-NS1.1 single-clone-derived cell line continued to proliferate for > 200 doubling levels and > 70 passages, continuing to maintain basal cell features (TP63+, KRT5+). When cultured on ALI, hSABCi-NS1.1 cells consistently formed tight junctions and differentiated into ciliated, club (SCGB1A1+), mucous (MUC5AC+, MUC5B+), neuroendocrine (CHGA+), ionocyte (FOXI1+) and surfactant protein positive cells (SFTPA+, SFTPB+, SFTPD+), observations confirmed by RNAseq and TaqMan PCR. Annotation enrichment analysis showed that "cilium" and "immunity" were enriched in functions of the top-1500 up-regulated genes. RNAseq reads alignment corroborated expression of CD4, CD74 and MHC-II. Compared to the large airway cell line BCi-NS1.1, differentiated of hSABCi-NS1.1 cells on ALI were enriched with small airway epithelial genes, including surfactant protein genes, LTF and small airway development relevant transcription factors NKX2-1, GATA6, SOX9, HOPX, ID2 and ETV5. Lentivirus-mediated expression of SPDEF in hSABCi-NS1.1 cells induced secretory cell metaplasia, accompanied with characteristic COPD-associated SAE secretory cell changes, including up-regulation of MSMB, CEACAM5 and down-regulation of LTF. CONCLUSIONS: The immortalized hSABCi-NS1.1 cell line has diverse differentiation capacities and retains SAE features, which will be useful for understanding the biology of SAE, the pathogenesis of SAE-related diseases, and testing new pharmacologic agents.


Assuntos
Sistema Respiratório/citologia , Células-Tronco , Diferenciação Celular , Linhagem Celular , Proliferação de Células , Técnicas Citológicas , Impedância Elétrica , Feminino , Expressão Gênica , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Células-Tronco/metabolismo , Telomerase/metabolismo , Junções Íntimas , Transcriptoma
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