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1.
Sci Rep ; 14(1): 7364, 2024 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-38548903

RESUMO

Esophagogastric variceal bleeding (EVB) is one of the common digestive system emergencies with poor prognosis and high rate of rebleeding after treatment. To explore the effects of endoscopic therapy and drug therapy on the prognosis and rebleeding of patients with EVB, and then select better treatment methods to effectively improve the prognosis. From January 2013 to December 2022, 965 patients with EVB who were hospitalized in gastroenterology Department of the 940 Hospital of Joint Logistic Support Forces of PLA were retrospectively analyzed. Patients were divided into endoscopic treatment group (ET, n = 586) and drug treatment group (DT, n = 379). Propensity score matching (PSM) analysis was performed in both groups, and the general information, efficacy and length of hospital stay were recorded. The patients were followed up for 3 months after bleeding control to determine whether rebleeding occurred. There were 286 cases in each group after PSM. Compared with DT group, ET had higher treatment success rate (P < 0.001), lower rebleeding rate (P < 0.001), lower mortality rate within 3 months, and no significant difference in total hospital stay (P > 0.05). Compared with drug therapy, endoscopic treatment of EVB has short-term efficacy advantages, and can effectively reduce the incidence of rebleeding and mortality within 3 months.


Assuntos
Varizes Esofágicas e Gástricas , Humanos , Varizes Esofágicas e Gástricas/complicações , Varizes Esofágicas e Gástricas/terapia , Estudos Retrospectivos , Hemorragia Gastrointestinal/etiologia , Hemorragia Gastrointestinal/terapia , Endoscopia/efeitos adversos , Prognóstico , Resultado do Tratamento , Recidiva
3.
Ecotoxicol Environ Saf ; 272: 116075, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38325273

RESUMO

Although animal studies have shown the reproductive toxicity of vanadium, less is known about its effects on semen quality in humans. Among 1135 healthy men who were screened as potential semen donors, we investigated the relationships of semen quality with urinary and seminal plasma vanadium levels via inductively coupled plasma-mass spectrometry (ICP-MS). Spearman rank correlation tests and linear regression models were used to assess the correlations between average urinary and within-individual pooled seminal plasma vanadium concentrations (n = 1135). We utilized linear mixed-effects models to evaluate the associations of urinary and seminal plasma vanadium levels (n = 1135) with repeated sperm quality parameters (n = 5576). Seminal plasma vanadium concentrations were not significantly correlated with urinary vanadium concentrations (r = 0.03). After adjusting for possible confounders, we observed inverse relationships of within-individual pooled seminal plasma vanadium levels with total count, semen volume, and sperm concentration (all P values for trend < 0.05). Specifically, subjects in the highest (vs. lowest) tertile of seminal plasma vanadium concentrations had - 11.3% (-16.4%, -5.9%), - 11.1% (-19.1%, -2.4%), and - 20.9% (-29.0%, -11.8%) lower sperm volume, concentration, and total count, respectively; moreover, urinary vanadium levels appeared to be negatively associated with sperm motility. These relationships showed monotonically decreasing dose-response patterns in the restricted cubic spline analyses. Our results demonstrated a poor correlation between urinary and seminal plasma levels of vanadium, and elevated vanadium concentrations in urine and seminal plasma may be adversely related to male semen quality.


Assuntos
Análise do Sêmen , Sêmen , Animais , Masculino , Humanos , Sêmen/química , Vanádio/toxicidade , Vanádio/análise , Motilidade dos Espermatozoides , Contagem de Espermatozoides , Espermatozoides/fisiologia
4.
BMC Public Health ; 24(1): 187, 2024 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-38225595

RESUMO

BACKGROUND: Magnesium (Mg) is both an essential macro-element and a known catalyst, and it plays a vital role in various physiological activities and mechanisms in relation to chronic kidney disease (CKD). However, epidemiological evidence involving this is limited and not entirely consistent. This study aims to explore the association of serum Mg concentrations with the risk of CKD among general Chinese adults. METHODS: A total of 8,277 Chinese adults were included in the wave of 2009 from the China Health and Nutrition Survey (CHNS). The primary outcome was the risk of CKD, which was defined as the estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2. Multivariable logistic regression model was used to examine the relationship of serum Mg concentrations with the risk of CKD. RESULTS: Included were 8,277 individuals, with an overall CKD prevalence of 11.8% (n = 977). Compared with the first quartile of serum Mg, the multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for participants in the second, third, and fourth quartiles of serum Mg were 0.74 (0.58, 0.93), 0.87 (0.69, 1.11) and 1.29 (1.03, 1.61), respectively. Similar results were observed in our several sensitivity analyses. Restricted cubic spline analysis demonstrated a nonlinear (similar "J"-shaped) association between serum Mg concentrations and the risk of CKD (Pnonlinearity <0.001), with a threshold at around a serum Mg value of 2.2 mg/dL. CONCLUSIONS: Our results suggested a similar "J"-shaped association between serum Mg concentration and the risk of CKD among Chinese adults. Further large prospective studies are needed to verify these findings.


Assuntos
Magnésio , Insuficiência Renal Crônica , Adulto , Humanos , Estudos Transversais , Insuficiência Renal Crônica/epidemiologia , Taxa de Filtração Glomerular , Inquéritos Epidemiológicos , Fatores de Risco
6.
Medicine (Baltimore) ; 102(29): e34314, 2023 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-37478226

RESUMO

BACKGROUND: Coronavirus disease 2019 (COVID-19) was first detected in December 2019, and declared as a pandemic by the World Health Organization (WHO) on March 11, 2020. The current management of COVID-19 is based generally on supportive therapy and treatment to prevent respiratory failure. METHODS: PubMed, Web of Science, Embase, CNKI, and other databases were searched by computer, and relevant literature published from December 2019 to November 2022 on the influencing factors of infection in close contacts with novel coronavirus pneumonia was collected. Meta-analysis was carried out after literature screening, quality assessment, and data extraction. RESULTS: A total of 425 articles were retrieved and 11 were included. Meta-analysis showed that there were 6 risk factors, and the combined OR value and 95% CI of each influencing factor were 5.23 (3.20, 8.57) for family members, 1.63 (0.56, 4.77) for regular contact, 2.14 (0.62, 7.32) for the elderly, 0.58 (0.001569.89) for cohabitation, 1.97 (1.02, 3.82) for women and 0.75 (0.01, 54.07) for others. The Deeks' funnel diagram indicates that there is no potential publication bias among the included studies. CONCLUSION: Family members and gender differences are the risk factors of infection among close contacts, and it cannot be proved that there are differences in infection among frequent contact, advanced age, and living together.


Assuntos
COVID-19 , Feminino , Humanos , Idoso , COVID-19/epidemiologia , SARS-CoV-2 , Pandemias/prevenção & controle , Fatores de Risco
7.
Rapid Commun Mass Spectrom ; 36(12): e9302, 2022 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-35344234

RESUMO

RATIONALE: Rankinidine belongs to the humantenine-type alkaloids isolated from Gelsemium. Currently, the mechanism behind the toxicity differences of rankinidine has not been explained. In this study, our purpose was to elucidate the major in vitro metabolic pathways of rankinidine and to compare the formation of metabolites of rankinidine in human (HLMs), rat (RLMs), goat (GLMs) and pig (PLMs) liver microsomes. METHODS: This is the first study to compare the in vitro metabolism of rankinidine with high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QTOF). The MS/MS data and LC/MS peak area acquired in positive ion mode were used to analyze metabolite structures and compare metabolism. RESULTS: We identified 11 metabolites (M1-M11) in total and found five main metabolic pathways, consisting of demethylation (M1), reduction (M2), oxidation at different positions (M3-M5), oxidation and reduction (M6-M10) and demethylation and oxidation (M11). The metabolism of rankinidine has qualitative and quantitative species-specific differences in vitro. In PLMs and GLMs, the main metabolic pathway of rankinidine was oxidation. Notably, among the four species, the oxidation ability of rankinidine was highest in pigs and goats, and the demethylation and reduction abilities of rankinidine were highest in humans and rats. CONCLUSIONS: The interspecific metabolic differences of rankinidine in HLMs, PLMs, GLMs and RLMs were compared and studied for the first time using LC/QTOF. These findings will certainly support future studies of rankinidine metabolism in vivo and will contribute to elucidating the cause of species-specific differences behind Gelsemium toxicity.


Assuntos
Alcaloides , Antineoplásicos , Gelsemium , Alcaloides/metabolismo , Animais , Cromatografia Líquida de Alta Pressão/métodos , Indóis , Microssomos Hepáticos/metabolismo , Ratos , Suínos , Espectrometria de Massas em Tandem/métodos
8.
Brain Sci ; 12(2)2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-35203954

RESUMO

Gelsemine is an active principle and a major alkaloid found in Gelsemium genus of plants belonging to the Loganiaceae family. The aim of the present study was to explore whether gelsemine exerts anxiolytic effects on a mouse model of chronic-unpredictable-mild-stress (CUMS)-induced anxiety-like behaviors. NOD-like receptor protein 3 (NLRP3) inflammasome, downregulated cAMP-response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) were also evaluated as potential mechanisms. First, gelsemine reversed a CUMS-induced decrease in body-weight gain in mice. Next, gelsemine alleviated CUMS-induced anxiety-like behaviors, as evidenced by the increased distance traveled in the central zone of the open-field test, both the increased percentage of time spent and distance traveled in the light compartment, the increased number of transitions between compartments in the light/dark-transition test, and the increased percentage of entries and time spent in the open arm of the elevated plus-maze. In addition, gelsemine decreased the levels of pro-inflammatory cytokines, including interleukin (IL)-1ß and IL-6, in the hypothalamus and hippocampus of CUMS mice. Interestingly, further investigations revealed that gelsemine inhibited the CUMS-induced activation of NLRP3-inflammasome pathways and downregulated CREB and BDNF overexpression in the hypothalamus. In summary, gelsemine alleviated anxiety-like behaviors in the CUMS-induced mouse model. Gelsemine exerted its anxiolytic effects by modulating the NLRP3 and CREB/BDNF pathways.

10.
Mol Cell ; 80(3): 410-422.e6, 2020 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-33108758

RESUMO

While effective anti-cancer drugs targeting the CHK1 kinase are advancing in the clinic, drug resistance is rapidly emerging. Here, we demonstrate that CRISPR-mediated knockout of the little-known gene FAM122A/PABIR1 confers cellular resistance to CHK1 inhibitors (CHK1is) and cross-resistance to ATR inhibitors. Knockout of FAM122A results in activation of PP2A-B55α, a phosphatase that dephosphorylates the WEE1 protein and rescues WEE1 from ubiquitin-mediated degradation. The resulting increase in WEE1 protein expression reduces replication stress, activates the G2/M checkpoint, and confers cellular resistance to CHK1is. Interestingly, in tumor cells with oncogene-driven replication stress, CHK1 can directly phosphorylate FAM122A, leading to activation of the PP2A-B55α phosphatase and increased WEE1 expression. A combination of a CHK1i plus a WEE1 inhibitor can overcome CHK1i resistance of these tumor cells, thereby enhancing anti-cancer activity. The FAM122A expression level in a tumor cell can serve as a useful biomarker for predicting CHK1i sensitivity or resistance.


Assuntos
Quinase 1 do Ponto de Checagem/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Fosfoproteínas/metabolismo , Pirazinas/farmacologia , Pirazóis/farmacologia , Animais , Apoptose/efeitos dos fármacos , Pontos de Checagem do Ciclo Celular , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Quinase 1 do Ponto de Checagem/antagonistas & inibidores , Quinase 1 do Ponto de Checagem/metabolismo , Dano ao DNA/efeitos dos fármacos , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Proteínas Nucleares/metabolismo , Fosfoproteínas/fisiologia , Fosforilação , Inibidores de Proteínas Quinases/farmacologia , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Proteínas Tirosina Quinases/genética , Pirazinas/metabolismo , Pirazóis/metabolismo , Transdução de Sinais/efeitos dos fármacos
11.
Nature ; 575(7783): 523-527, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31723267

RESUMO

The protection of telomere ends by the shelterin complex prevents DNA damage signalling and promiscuous repair at chromosome ends. Evidence suggests that the 3' single-stranded telomere end can assemble into a lasso-like t-loop configuration1,2, which has been proposed to safeguard chromosome ends from being recognized as DNA double-strand breaks2. Mechanisms must also exist to transiently disassemble t-loops to allow accurate telomere replication and to permit telomerase access to the 3' end to solve the end-replication problem. However, the regulation and physiological importance of t-loops in the protection of telomere ends remains unknown. Here we identify a CDK phosphorylation site in the shelterin subunit at Ser365 of TRF2, whose dephosphorylation in S phase by the PP6R3 phosphatase provides a narrow window during which the RTEL1 helicase can transiently access and unwind t-loops to facilitate telomere replication. Re-phosphorylation of TRF2 at Ser365 outside of S phase is required to release RTEL1 from telomeres, which not only protects t-loops from promiscuous unwinding and inappropriate activation of ATM, but also counteracts replication conflicts at DNA secondary structures that arise within telomeres and across the genome. Hence, a phospho-switch in TRF2 coordinates the assembly and disassembly of t-loops during the cell cycle, which protects telomeres from replication stress and an unscheduled DNA damage response.


Assuntos
Ciclo Celular , Quinases Ciclina-Dependentes/metabolismo , Fosfosserina/metabolismo , Telômero/metabolismo , Proteína 2 de Ligação a Repetições Teloméricas/química , Proteína 2 de Ligação a Repetições Teloméricas/metabolismo , Animais , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , DNA/biossíntese , DNA/química , DNA/metabolismo , Quebras de DNA de Cadeia Dupla , Dano ao DNA , DNA Helicases/metabolismo , Reparo do DNA , Replicação do DNA , Fibroblastos , Genoma/genética , Células HEK293 , Humanos , Camundongos , Mutação , Fenótipo , Monoéster Fosfórico Hidrolases/metabolismo , Fosforilação , Antígeno Nuclear de Célula em Proliferação/metabolismo , Fase S , Complexo Shelterina , Telomerase/metabolismo , Telômero/genética , Proteínas de Ligação a Telômeros/química , Proteínas de Ligação a Telômeros/metabolismo , Proteína 2 de Ligação a Repetições Teloméricas/genética
12.
Nat Commun ; 10(1): 4252, 2019 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-31534152

RESUMO

Mitotic cells attenuate the DNA damage response (DDR) by phosphorylating 53BP1, a critical DDR mediator, to prevent its localization to damaged chromatin. Timely dephosphorylation of 53BP1 is critical for genome integrity, as premature recruitment of 53BP1 to DNA lesions impairs mitotic fidelity. Protein phosphatase 4 (PP4) dephosphorylates 53BP1 in late mitosis to allow its recruitment to DNA lesions in G1. How cells appropriately dephosphorylate 53BP1, thereby restoring DDR, is unclear. Here, we elucidate the underlying mechanism of kinetic control of 53BP1 dephosphorylation in mitosis. We demonstrate that CDK5, a kinase primarily functional in post-mitotic neurons, is active in late mitotic phases in non-neuronal cells and directly phosphorylates PP4R3ß, the PP4 regulatory subunit that recognizes 53BP1. Specific inhibition of CDK5 in mitosis abrogates PP4R3ß phosphorylation and abolishes its recognition and dephosphorylation of 53BP1, ultimately preventing the localization of 53BP1 to damaged chromatin. Our results establish CDK5 as a regulator of 53BP1 recruitment.


Assuntos
Quinase 5 Dependente de Ciclina/metabolismo , Reparo do DNA/genética , Fase G1/genética , Fosfoproteínas Fosfatases/metabolismo , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo , Linhagem Celular Tumoral , Dano ao DNA/genética , Células HEK293 , Células HeLa , Humanos , Mitose/genética , Fosforilação , Interferência de RNA , RNA Interferente Pequeno/genética , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/genética
13.
Brain Res Bull ; 149: 148-155, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31002911

RESUMO

Neonatal exposure to propofol induces persistent behavioral abnormalities in adulthood. In addition to triggering the apoptosis of neurons in the developing brain, anesthetics may contribute to the development of cognitive deficits by interfering neurogenesis. Given the importance of neural stem cell (NSC) proliferation in neurogenesis, the effect of propofol on NSC proliferation and the mechanisms underlying this effect were investigated. Hippocampal NSC proliferation from neonatal rats was examined using 5-bromo-2'-deoxyuridine incorporation assays in vitro. The [Ca2+]i was analyzed using flow cytometry. The activations of protein kinase C (PKC)-α and extracellular signal-regulated kinases 1/2 (ERK1/2) were measured by western blot. Our results showed that propofol significantly inhibited NSC proliferation in vitro. [Ca2+]i and activations of PKCα and ERK1/2 in NSCs were markedly suppressed by propofol (5, 10, 20, 40 and 80 µM). Ca2+ channel blocker verapamil, PKCα inhibitor chelerythrine and ERK1/2 kinase inhibitor PD98059 exerted their maximal effects on NSC function at concentrations of 20, 10 and 20 µM, respectively. Propofol (20 µM) could not produce further additional suppression effects when used in combination with verapamil (20 µM), chelerythrine (10 µM) or PD98059 (20 µM). In addition, phorbol-12-myristate-13-acetate (PMA, a activator of PKC) markedly attenuated the suppressive effects of propofol on ERK1/2 phosphorylation and NSC proliferation. The inhibition effects on PKCα activation, ERK1/2 phosphorylation and NSC proliferation induced by propofol were significantly improved by BayK8644 (a calcium channel agonist). These results indicate that propofol can inhibits hippocampal NSC proliferation by suppressing the Ca2+-PKCα-ERK1/2 signaling pathway.


Assuntos
Células-Tronco Neurais/efeitos dos fármacos , Propofol/farmacologia , Animais , Animais Recém-Nascidos/metabolismo , Apoptose/efeitos dos fármacos , Encéfalo/metabolismo , Cálcio/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Hipocampo/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Células-Tronco Neurais/metabolismo , Neurogênese/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Fosforilação/efeitos dos fármacos , Propofol/metabolismo , Proteína Quinase C-alfa/metabolismo , Ratos , Transdução de Sinais/efeitos dos fármacos
14.
Nature ; 543(7644): 211-216, 2017 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-28241136

RESUMO

P53-binding protein 1 (53BP1) is a multi-functional double-strand break repair protein that is essential for class switch recombination in B lymphocytes and for sensitizing BRCA1-deficient tumours to poly-ADP-ribose polymerase-1 (PARP) inhibitors. Central to all 53BP1 activities is its recruitment to double-strand breaks via the interaction of the tandem Tudor domain with dimethylated lysine 20 of histone H4 (H4K20me2). Here we identify an uncharacterized protein, Tudor interacting repair regulator (TIRR), that directly binds the tandem Tudor domain and masks its H4K20me2 binding motif. Upon DNA damage, the protein kinase ataxia-telangiectasia mutated (ATM) phosphorylates 53BP1 and recruits RAP1-interacting factor 1 (RIF1) to dissociate the 53BP1-TIRR complex. However, overexpression of TIRR impedes 53BP1 function by blocking its localization to double-strand breaks. Depletion of TIRR destabilizes 53BP1 in the nuclear-soluble fraction and alters the double-strand break-induced protein complex centring 53BP1. These findings identify TIRR as a new factor that influences double-strand break repair using a unique mechanism of masking the histone methyl-lysine binding function of 53BP1.


Assuntos
Proteínas de Transporte/metabolismo , Histonas/química , Histonas/metabolismo , Lisina/metabolismo , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/antagonistas & inibidores , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo , Animais , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Sítios de Ligação , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Feminino , Humanos , Metilação , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação , Ligação Proteica , Domínios Proteicos , Proteínas de Ligação a RNA , Proteínas de Ligação a Telômeros/metabolismo , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/química
16.
Medicine (Baltimore) ; 96(47): e8872, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29382008

RESUMO

RATIONALE: A cecal submucosal fecalith is extremely rare and is likely to be misdiagnosed as appendicitis with an incarcerated fecalith. PATIENT CONCERNS: This review presents the case of a female patient complaining of recurrent abdominal pain in the right lower quadrant, similar to the clinical symptoms of appendicitis. Physical examination revealed an abdominal tenderness in the right lower quadrant without rebound tenderness or muscular tension. An ultrasound examination found a mass located in the right lower abdomen. Computed tomography showed a high-density shadow in the cecal cavity. DIAGNOSES: A fecalith was detected in the submucosal cecal wall. The postoperative pathologic examination showed that the fecalith was located in the submucosa. INTERVENTIONS: A partial cecal excision was performed under laparoscopic surgery assisted by colonoscopy. OUTCOMES: The patient was discharged 1 week after surgery without postoperative complications. LESSONS: Fecaliths should be considered in the differential diagnosis of submucosal occupying lesions of the cecum.


Assuntos
Apendicite/diagnóstico , Doenças do Ceco/cirurgia , Colonoscopia/métodos , Impacção Fecal/cirurgia , Laparoscopia/métodos , Idoso , Diagnóstico Diferencial , Erros de Diagnóstico , Feminino , Humanos , Mucosa Intestinal/cirurgia
17.
Oncol Lett ; 11(3): 2155-2163, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26998141

RESUMO

MicroRNAs are important in cancer development and progression. In the present study, the clinical significance and function of microRNA-711 (miR-711) expression in breast cancer were investigated. The expression level of miR-711 was analyzed in breast cancer tissue samples using reverse transcription-quantitative polymerase chain reaction. Cell proliferation, colony formation, apoptosis and Transwell assays were performed in breast cancer cell lines transfected with miR-711 mimics or inhibitors, or control sequence. miR-711 was found to be upregulated in 30 formalin-fixed paraffin-embedded breast cancer tissue samples compared with paired non-cancerous breast tissues (P<0.05). Furthermore, a higher miR-711 expression was demonstrated to be associated with poor overall and disease-free survival times in 161 breast cancer patients, and miR-711 was identified as an independent prognostic factor using multivariate Cox regression analysis. In vitro, overexpression of miR-711 resulted in a significant increase in proliferation, colony formation, migration and invasion of breast cancer cells. By contrast, downregulating miR-711 inhibited cell proliferation, colony formation, migration and invasion and enhanced the rate of apoptosis of breast cancer cells. To the best of our knowledge, the present study is the first to demonstrate that miR-711 is an independent prognostic factor and serves an important oncogenic function in breast cancer, suggesting that miR-711 is a potential biomarker of prognosis and a molecular therapeutic target in breast cancer.

18.
Genes Dev ; 30(6): 687-99, 2016 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-26966246

RESUMO

We identified Mte1 (Mph1-associated telomere maintenance protein 1) as a multifunctional regulator of Saccharomyces cerevisiae Mph1, a member of the FANCM family of DNA motor proteins important for DNA replication fork repair and crossover suppression during homologous recombination. We show that Mte1 interacts with Mph1 and DNA species that resemble a DNA replication fork and the D loop formed during recombination. Biochemically, Mte1 stimulates Mph1-mediated DNA replication fork regression and branch migration in a model substrate. Consistent with this activity, genetic analysis reveals that Mte1 functions with Mph1 and the associated MHF complex in replication fork repair. Surprisingly, Mte1 antagonizes the D-loop-dissociative activity of Mph1-MHF and exerts a procrossover role in mitotic recombination. We further show that the influence of Mte1 on Mph1 activities requires its binding to Mph1 and DNA. Thus, Mte1 differentially regulates Mph1 activities to achieve distinct outcomes in recombination and replication fork repair.


Assuntos
RNA Helicases DEAD-box/metabolismo , Replicação do DNA/fisiologia , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Ligação a Telômeros/metabolismo , RNA Helicases DEAD-box/genética , Reparo do DNA/genética , Epistasia Genética , Deleção de Genes , Regulação Fúngica da Expressão Gênica , Mitose , Ligação Proteica , Multimerização Proteica , Estrutura Terciária de Proteína , Proteínas de Saccharomyces cerevisiae/genética
19.
DNA Repair (Amst) ; 32: 58-65, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25956864

RESUMO

Phosphorylation signaling networks have primarily been studied from an activation perspective, with protein phosphatases viewed as simple counter-balances that functioned passively in the wake of kinase activity. Indeed, there have been only sporadic efforts to investigate the independent role of phosphatases in DNA damage response (DDR). However, global phosphoproteomic analysis of the DDR revealed that over one-third of observed phosphorylation sites were down-regulated within minutes of DNA damage, suggesting a more robust role for phosphatases in DNA repair. Consistent with these observations, recent studies reveal that dephosphorylation of DNA repair factors during specific phases of the cell cycle may be a pre-requisite for their participation in the DDR. Here, we summarize recent literature and speculate on the emerging role of phosphatases in the DDR.


Assuntos
Reparo do DNA , DNA/metabolismo , Fosfoproteínas Fosfatases/genética , Transdução de Sinais , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , DNA/química , Quebras de DNA de Cadeia Dupla , Regulação da Expressão Gênica , Humanos , Fosfoproteínas Fosfatases/metabolismo , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Fosforilação
20.
Nat Commun ; 5: 2987, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24390579

RESUMO

The conserved MHF1-MHF2 (MHF) complex functions in the activation of the Fanconi anaemia pathway of the DNA damage response, in regulating homologous recombination, and in DNA replication fork maintenance. MHF facilitates the processing of multiple types of branched DNAs by the DNA translocase FANCM. Here we report the crystal structure of a human MHF-DNA complex that reveals the DNA-binding mode of MHF. The structure suggests that MHF prefers branched DNA over double-stranded DNA because it engages two duplex arms. Biochemical analyses verify that MHF preferentially engages DNA forks or various four-way junctions independent of the junction-site structure. Furthermore, genetic experiments provide evidence that the observed DNA-binding interface of MHF is important for cellular resistance to DNA damage. These results offer insights into how the MHF complex recognizes branched DNA and stimulates FANCM activity at such a structure to promote genome maintenance.


Assuntos
Proteínas Reguladoras de Apoptose/metabolismo , Dano ao DNA/genética , DNA Helicases/metabolismo , Reparo do DNA/genética , Proteínas de Ligação a DNA/metabolismo , DNA/metabolismo , Proteínas Nucleares/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Cristalografia por Raios X , DNA Helicases/genética , Anemia de Fanconi/genética , Anemia de Fanconi/metabolismo , Humanos , Modelos Moleculares , Estrutura Terciária de Proteína
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