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The Arabidopsis thaliana Receptor-Like Protein RLP30 contributes to immunity against the fungal pathogen Sclerotinia sclerotiorum. Here we identify the RLP30-ligand as a small cysteine-rich protein (SCP) that occurs in many fungi and oomycetes and is also recognized by the Nicotiana benthamiana RLP RE02. However, RLP30 and RE02 share little sequence similarity and respond to different parts of the native/folded protein. Moreover, some Brassicaceae other than Arabidopsis also respond to a linear SCP peptide instead of the folded protein, suggesting that SCP is an eminent immune target that led to the convergent evolution of distinct immune receptors in plants. Surprisingly, RLP30 shows a second ligand specificity for a SCP-nonhomologous protein secreted by bacterial Pseudomonads. RLP30 expression in N. tabacum results in quantitatively lower susceptibility to bacterial, fungal and oomycete pathogens, thus demonstrating that detection of immunogenic patterns by Arabidopsis RLP30 is involved in defense against pathogens from three microbial kingdoms.
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Proteínas de Arabidopsis , Arabidopsis , Oomicetos , Arabidopsis/metabolismo , Cisteína/metabolismo , Ligantes , Proteínas/metabolismo , Oomicetos/metabolismo , Bactérias/metabolismo , Receptores de Reconhecimento de Padrão/metabolismo , Doenças das Plantas/microbiologia , Imunidade Vegetal , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Regulação da Expressão Gênica de PlantasRESUMO
T cells play a critical role in the control of cancer. The development of immune checkpoint blockers (ICB) aimed at enhancing antitumor T-cell responses has revolutionized cancer treatment. However, durable clinical benefit is observed in only a subset of patients, prompting research efforts to focus on strategies that target multiple inhibitory signals within the tumor microenvironment (TME) to limit tumor evasion and improve patient outcomes. Adenosine has emerged as a potent immune suppressant within the TME, and CD73 is the major enzyme responsible for its extracellular production. CD73 can be co-opted within the TME to impair T-cell-mediated antitumor immunity and promote tumor growth. To target this pathway and block the formation of adenosine, we designed a novel, selective, and potent class of small-molecule inhibitors of CD73, including AB680 (quemliclustat), which is currently being tested in patients with cancer. AB680 effectively restored T-cell proliferation, cytokine secretion, and cytotoxicity that were dampened by the formation of immunosuppressive adenosine by CD73. Furthermore, in an allogeneic mixed lymphocyte reaction where CD73-derived adenosine had a dominant suppressive effect in the presence of PD-1 blockade, AB680 restored T-cell activation and function. Finally, in a preclinical mouse model of melanoma, AB680 inhibited CD73 in the TME and increased the antitumor activity of PD-1 blockade. Collectively, these data provide a rationale for the inhibition of CD73 with AB680 in combination with ICB, such as anti-PD-1, to improve cancer patient outcomes.
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Melanoma , Receptor de Morte Celular Programada 1 , Adenosina/metabolismo , Adenosina/farmacologia , Adenosina/uso terapêutico , Animais , Humanos , Inibidores de Checkpoint Imunológico , Melanoma/tratamento farmacológico , Camundongos , Receptor de Morte Celular Programada 1/metabolismo , Microambiente TumoralRESUMO
BACKGROUND: Long-term disability to work is a risk factor for a permanent reduction in income. Rehabilitation care can support people to return to work. In Germany, rehabilitation care to return to work is mostly provided in specialised clinics. The aim of the Rehapro-SERVE study is to reduce work disability days by facilitating rehabilitation care planning using a digital communication platform. To investigate the feasibility, we will test the implementation of the digital platform and evaluate the study procedures. The Rehapro-SERVE study is funded by the German Federal Ministry of Labour and Social Affairs (BMAS) (grant number: 661R0053K1). METHOD: The feasibility study includes a two-armed unblinded block randomised controlled study (RCT) without follow-up assessments as well as an interview study. Participants for the RCT (n = 16) are primary care patients with a minimum of 4 weeks of absence from work due to musculoskeletal, oncological or psychological conditions and at high risk of early retirement. Eligibility criteria are age 40 to 60 years; minimum of 4 weeks continuous sick leave before recruitment due to musculoskeletal, mental health or oncological conditions; and being at high risk of early retirement. Patients will be recruited from 8 primary care practices in urban and rural areas in Hesse, Germany. Following baseline assessments, patients will be randomised to either digitalised care planning (treatment) or a control group. The digitalised care planning platform will include the patients' primary care physicians, jobcentres and public health physicians to decide on a tailored return-to-work programme. The collaboration will be supported by a case administrator and, if considered beneficial, a social worker for the patient. An interview study will evaluate the acceptability of the study procedures and the intervention. DISCUSSION: The use of a digital communication platform enables stakeholders to exchange information and discuss rehabilitation care planning in a timely fashion. The results of the feasibility study will lead to the adaptation of study procedures for the main study. The results will support the design and conduct of similar studies including digital applications in primary care or across different healthcare settings. TRIAL REGISTRATION: DRKS - German Clinical Trials Register, DRKS00024207 . Registered on 22 March 2021.
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BACKGROUND: Cough is a relevant reason for encounter in primary care. For evidence-based decision making, general practitioners need setting-specific knowledge about prevalences, pre-test probabilities, and prognosis. Accordingly, we performed a systematic review of symptom-evaluating studies evaluating cough as reason for encounter in primary care. METHODS: We conducted a search in MEDLINE and EMBASE. Eligibility criteria and methodological quality were assessed independently by two reviewers. We extracted data on prevalence, aetiologies and prognosis, and estimated the variation across studies. If justifiable in terms of heterogeneity, we performed a meta-analysis. RESULTS: We identified 21 eligible studies on prevalence, 12 on aetiology, and four on prognosis. Prevalence/incidence estimates were 3.8-4.2%/12.5% (Western primary care) and 10.3-13.8%/6.3-6.5% in Africa, Asia and South America. In Western countries the underlying diagnoses for acute cough or cough of all durations were respiratory tract infections (73-91.9%), influenza (6-15.2%), asthma (3.2-15%), laryngitis/tracheitis (3.6-9%), pneumonia (4.0-4.2%), COPD (0.5-3.3%), heart failure (0.3%), and suspected malignancy (0.2-1.8%). Median time for recovery was 9 to 11 days. Complete recovery was reported by 40.2- 67% of patients after two weeks, and by 79% after four weeks. About 21.1-35% of patients re-consulted; 0-1.3% of acute cough patients were hospitalized, none died. Evidence is missing concerning subacute and chronic cough. CONCLUSION: Prevalences and incidences of cough are high and show regional variation. Acute cough, mainly caused by respiratory tract infections, is usually self-limiting (supporting a "wait-and-see" strategy). We have no setting-specific evidence to support current guideline recommendations concerning subacute or chronic cough in Western primary care. Our study presents epidemiological data under non non-pandemic conditions. It will be interesting to compare these data to future research results of the post-pandemic era.
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Tosse , Atenção Primária à Saúde , Doença Crônica , Tosse/epidemiologia , Tosse/etiologia , Humanos , Prevalência , PrognósticoRESUMO
OBJECTIVE: Due to the increasing concerns about polypharmacy, there is a growing need for clinical recommendations for drug discontinuation. This requires studies investigating the process on several levels. This paper addresses the methodological problems of drug discontinuation trials (DDTs). To that end, we offer a new typology of research aims and corresponding methodological recommendations for trials evaluating drug discontinuation. STUDY DESIGN AND SETTING: Multi-stage development process, including literature search and expert panels. RESULTS: Clinical trials are only required in cases of scientific uncertainty. We identified three situations of uncertainty associated with drug discontinuation from which we derived three study types: 1) Uncertainty regarding the effectiveness and/or safety of a drug; 2) Uncertainty regarding the procedure of discontinuing a previously taken drug; 3) Uncertainty regarding the effectiveness of complex strategies used to discontinue one or more drugs. We developed specific methodological recommendations for each study type. CONCLUSION: We offer a comprehensive definition of research aims, study designs, and methodological recommendations regarding DDTs. The typology we propose can help investigators clarify their research aims and study design. The type-specific methodological recommendation should improve the quality of future drug discontinuation trials.
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Tratamento Farmacológico , Término Precoce de Ensaios Clínicos/métodos , Humanos , Guias de Prática Clínica como Assunto , IncertezaRESUMO
INTRODUCTION: Brain bioenergetics are defective in Alzheimer's disease (AD). Preclinical studies find oxaloacetate (OAA) enhances bioenergetics, but human safety and target engagement data are lacking. METHODS: We orally administered 500 or 1000 mg OAA, twice daily for 1 month, to AD participants (n = 15 each group) and monitored safety and tolerability. To assess brain metabolism engagement, we performed fluorodeoxyglucose positron emission tomography (FDG PET) and magnetic resonance spectroscopy before and after the intervention. We also assessed pharmacokinetics and cognitive performance. RESULTS: Both doses were safe and tolerated. Compared to the lower dose, the higher dose benefited FDG PET glucose uptake across multiple brain regions (P < .05), and the higher dose increased parietal and frontoparietal glutathione (P < .05). We did not demonstrate consistent blood level changes and cognitive scores did not improve. CONCLUSIONS: 1000 mg OAA, taken twice daily for 1 month, is safe in AD patients and engages brain energy metabolism.
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Doença de Alzheimer/tratamento farmacológico , Ácido Oxaloacético/administração & dosagem , Ácido Oxaloacético/uso terapêutico , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/psicologia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Cognição/efeitos dos fármacos , Relação Dose-Resposta a Droga , Metabolismo Energético/efeitos dos fármacos , Feminino , Fluordesoxiglucose F18 , Glucose/metabolismo , Glutationa/metabolismo , Humanos , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Testes Neuropsicológicos , Ácido Oxaloacético/efeitos adversos , Tomografia por Emissão de Pósitrons , Compostos RadiofarmacêuticosRESUMO
Angiosperms possess enormous morphological variation in plant architectures and floral forms. Previous studies in Pentapetalae and monocots have demonstrated the involvement of TCP domain CYCLOIDEA/TEOSINTE BRANCHED1-like (CYC/TB1) genes in the control of floral symmetry and shoot branching. However, how TCP/CYC-like (CYL) genes originated, evolved and functionally diversified remain unclear. We conducted a comparative functional study in Ranunculales, the sister lineage to all other eudicots, between Eschscholzia californica and Cysticapnos vesicaria, two species of Papaveraceae with actinomorphic and zygomorphic flowers, respectively. Phylogenetic analysis indicates that CYL genes in Papaveraceae form two paralogous lineages, PapaCYL1 and PapaCYL2. Papaveraceae CYL genes show highly diversified expression patterns as well as functions. Enhanced branching by silencing of EscaCYL1 suggests that the role of CYC/TB1-like genes in branching control is conserved in Papaveraceae. In contrast to the arrest of stamen development in Pentapetalae, PapaCYL genes promote stamen initiation and growth. In addition, we demonstrate that CyveCYLs are involved in perianth development, specifying sepal and petal identity in Cysticapnos by regulating the B-class floral organ identity genes. Our data also suggest the involvement of CyveCYL genes in the regulation of flower symmetry in Cysticapnos. Our work provides evidence of the importance of TCP/CYC-like genes in the promotion of morphological diversity across angiosperms.
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Evolução Molecular , Flores/anatomia & histologia , Variação Genética , Papaveraceae/genética , Proteínas de Plantas/genética , Homologia de Sequência de Aminoácidos , Flores/ultraestrutura , Regulação da Expressão Gênica de Plantas , Inativação Gênica , Genes de Plantas , Tamanho do Órgão/genética , Papaveraceae/ultraestrutura , Fenótipo , Proteínas de Plantas/metabolismo , Brotos de Planta/crescimento & desenvolvimentoRESUMO
In the last ten years opioid prescription has increased considerably. It is not that cancer patients would receive more analgesics, but it rather can be traced to a rising use of opioids for non cancer chronic pain (NCCP). There is evidence that serious opioid overuse may be present. Why should NCCP patients not benefit from opioid therapy and which side effects would justify to deprive NCCP patients of these strong analgesics? Our article summarizes the current discussion on opioid use in NCCP and outlines current evidence.
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Analgésicos Opioides/efeitos adversos , Analgésicos Opioides/uso terapêutico , Dor Crônica/tratamento farmacológico , Manejo da Dor/efeitos adversos , Transtornos Relacionados ao Uso de Substâncias/etiologia , Humanos , Transtornos Relacionados ao Uso de OpioidesRESUMO
Tumor-secreted extracellular vesicles (EVs) are critical mediators of intercellular communication between tumor cells and stromal cells in local and distant microenvironments. Accordingly, EVs play an essential role in both primary tumor growth and metastatic evolution. EVs orchestrate multiple systemic pathophysiological processes, such as coagulation, vascular leakiness, and reprogramming of stromal recipient cells to support pre-metastatic niche formation and subsequent metastasis. Clinically, EVs may be biomarkers and novel therapeutic targets for cancer progression, particularly for predicting and preventing future metastatic development.
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Biomarcadores Tumorais/metabolismo , Vesículas Extracelulares/metabolismo , Neoplasias/patologia , Comunicação Celular , Exossomos , Humanos , Metástase Neoplásica , Neoplasias/metabolismo , Prognóstico , Microambiente TumoralRESUMO
BACKGROUND: Tiredness is one of the most frequent complaints in primary care. Although often self-limiting and frequently associated with psychosocial stress, patients but also their physicians are often uncertain regarding a serious cause and appropriate diagnostic work-up. We conducted a systematic review and meta-analysis of studies reporting on differential diagnosis of fatigue in primary care. METHODS: MEDLINE, EMBASE and conference abstracts were searched for primary care based studies of patients presenting with tiredness. Twenty-six studies were included. We report on anaemia, malignancy, serious organic disease, depression and the chronic fatigue syndrome (CFS) as causes of tiredness as presenting complaint. RESULTS: We found considerable heterogeneity of estimates which was reduced by limiting our analysis to high quality studies. Prevalences were as follows-anaemia: 2.8 % (CI (confidence interval) 1.6-4.8 %); malignancy: 0.6 % (CI 0.3-1.3 %); serious somatic disease: 4.3 % (CI 2.7-6.7 %); depression 18.5 % (CI 16.2-21.0 %). Pooling was not appropriate for CFS. In studies with control groups of patients without the symptom of tiredness, prevalence of somatic disease was identical to those complaining of tiredness. Depression, however, was more frequent among those with tiredness. CONCLUSIONS: Serious somatic disease is rare in patients complaining of tiredness. Since prevalence is similar in patients without tiredness, the association may not be causal. Extensive investigations are only warranted in case of specific findings from the history or clinical examination. Instead, attention should focus on depression and psychosocial problems.
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Anemia/diagnóstico , Depressão/diagnóstico , Síndrome de Fadiga Crônica/diagnóstico , Fadiga/etiologia , Neoplasias/diagnóstico , Anemia/complicações , Depressão/complicações , Diagnóstico Diferencial , Síndrome de Fadiga Crônica/complicações , Humanos , Neoplasias/complicaçõesRESUMO
The epigenetic information encoded in the genomic DNA methylation pattern is translated by methylcytosine binding proteins like MeCP2 into chromatin topology and structure and gene activity states. We have shown previously that the MeCP2 level increases during differentiation and that it causes large-scale chromatin reorganization, which is disturbed by MeCP2 Rett syndrome mutations. Phosphorylation and other posttranslational modifications of MeCP2 have been described recently to modulate its function. Here we show poly(ADP-ribosyl)ation of endogenous MeCP2 in mouse brain tissue. Consequently, we found that MeCP2 induced aggregation of pericentric heterochromatin and that its chromatin accumulation was enhanced in poly(ADP-ribose) polymerase (PARP) 1(-/-) compared with wild-type cells. We mapped the poly(ADP-ribosyl)ation domains and engineered MeCP2 mutation constructs to further analyze potential effects on DNA binding affinity and large-scale chromatin remodeling. Single or double deletion of the poly(ADP-ribosyl)ated regions and PARP inhibition increased the heterochromatin clustering ability of MeCP2. Increased chromatin clustering may reflect increased binding affinity. In agreement with this hypothesis, we found that PARP-1 deficiency significantly increased the chromatin binding affinity of MeCP2 in vivo. These data provide novel mechanistic insights into the regulation of MeCP2-mediated, higher-order chromatin architecture and suggest therapeutic opportunities to manipulate MeCP2 function.
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Cromatina/química , Proteína 2 de Ligação a Metil-CpG/metabolismo , Poli Adenosina Difosfato Ribose/metabolismo , Poli(ADP-Ribose) Polimerases/metabolismo , Processamento de Proteína Pós-Traducional , Animais , Sítios de Ligação , Encéfalo/metabolismo , Cromatina/metabolismo , Células HEK293 , Humanos , Proteína 2 de Ligação a Metil-CpG/química , Proteína 2 de Ligação a Metil-CpG/genética , Camundongos , Mutação , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/genética , Ligação Proteica , Ratos , Células Sf9 , SpodopteraRESUMO
Pancreatic ductal adenocarcinomas (PDACs) are highly metastatic with poor prognosis, mainly due to delayed detection. We hypothesized that intercellular communication is critical for metastatic progression. Here, we show that PDAC-derived exosomes induce liver pre-metastatic niche formation in naive mice and consequently increase liver metastatic burden. Uptake of PDAC-derived exosomes by Kupffer cells caused transforming growth factor ß secretion and upregulation of fibronectin production by hepatic stellate cells. This fibrotic microenvironment enhanced recruitment of bone marrow-derived macrophages. We found that macrophage migration inhibitory factor (MIF) was highly expressed in PDAC-derived exosomes, and its blockade prevented liver pre-metastatic niche formation and metastasis. Compared with patients whose pancreatic tumours did not progress, MIF was markedly higher in exosomes from stage I PDAC patients who later developed liver metastasis. These findings suggest that exosomal MIF primes the liver for metastasis and may be a prognostic marker for the development of PDAC liver metastasis.
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Carcinoma Ductal Pancreático/patologia , Exossomos/metabolismo , Neoplasias Hepáticas/patologia , Fatores Inibidores da Migração de Macrófagos/biossíntese , Neoplasias Pancreáticas/patologia , Animais , Sequência de Bases , Células da Medula Óssea/imunologia , Linhagem Celular Tumoral , Movimento Celular , Feminino , Fibronectinas/biossíntese , Regulação Neoplásica da Expressão Gênica , Células Estreladas do Fígado/patologia , Humanos , Fígado/citologia , Fígado/patologia , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/secundário , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Lesões Pré-Cancerosas/patologia , Interferência de RNA , RNA Interferente Pequeno , Análise de Sequência de RNA , Transdução de Sinais , Fator de Crescimento Transformador beta/metabolismoRESUMO
BACKGROUND: Diagnostic reasoning in primary care patients with abdominal pain is a complex challenge for GPs. To ensure evidence-based decision making for this symptom, GPs need setting-specific knowledge about the prevalence, potential risks for diseases and chance of recovery or risk of undesirable courses of disease. AIM: We conducted a systematic review of symptom-evaluating studies on prevalence, aetiology or prognosis of abdominal pain. METHODS: We included all studies evaluating the symptom 'abdominal pain' as a reason for consultation in primary care. We included all types of study designs except for qualitative studies. Studies focussed solely on children or settings other than primary care were also excluded. RESULTS: We identified 14 studies. Mean consultation prevalence is 2.8% for abdominal pain. In about one-third of patients the underlying cause of abdominal pain cannot be specified. The most common aetiologies are gastroenteritis (7.2-18.7%), irritable bowel disease (2.6-13.2%), urological cause (5.3%) and gastritis (5.2%). About 1 in 10 abdominal pain patients suffers from an acute disease like appendicitis (1.9%), diverticulitis (3.0%), biliary/pancreatic (4.0%) or neoplastic (1.0%) diseases needing immediate therapy. CONCLUSION: There is a high prevalence of patients consulting GPs for abdominal pain. The review identified a comparably high rate of acute underlying diseases in need of further investigation or therapy. At the same time, the underlying cause of the complaints often remains unexplained. Further symptom-evaluating studies are necessary, ideally using standardized methodology in order to gain sufficient evidence for developing much-needed guidelines and decision support tools.
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Dor Abdominal/epidemiologia , Dor Abdominal/etiologia , Gastroenterite/complicações , Medicina Geral/estatística & dados numéricos , Neoplasias/complicações , Doenças Biliares/complicações , Humanos , Síndrome do Intestino Irritável/complicações , Pancreatopatias/complicações , Prevalência , Prognóstico , Encaminhamento e Consulta/estatística & dados numéricos , Doenças Urológicas/complicaçõesAssuntos
Biomarcadores Tumorais/genética , DNA/metabolismo , Exossomos/genética , Neoplasias/diagnóstico , Animais , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Detecção Precoce de Câncer , Exossomos/metabolismo , Células HCT116 , Humanos , Células K562 , Camundongos , Neoplasias/metabolismoRESUMO
The Brassicaceae, including Arabidopsis thaliana and Brassica crops, is unmatched among plants in its wealth of genomic and functional molecular data and has long served as a model for understanding gene, genome, and trait evolution. However, genome information from a phylogenetic outgroup that is essential for inferring directionality of evolutionary change has been lacking. We therefore sequenced the genome of the spider flower (Tarenaya hassleriana) from the Brassicaceae sister family, the Cleomaceae. By comparative analysis of the two lineages, we show that genome evolution following ancient polyploidy and gene duplication events affect reproductively important traits. We found an ancient genome triplication in Tarenaya (Th-α) that is independent of the Brassicaceae-specific duplication (At-α) and nested Brassica (Br-α) triplication. To showcase the potential of sister lineage genome analysis, we investigated the state of floral developmental genes and show Brassica retains twice as many floral MADS (for minichromosome maintenance1, AGAMOUS, DEFICIENS and serum response factor) genes as Tarenaya that likely contribute to morphological diversity in Brassica. We also performed synteny analysis of gene families that confer self-incompatibility in Brassicaceae and found that the critical serine receptor kinase receptor gene is derived from a lineage-specific tandem duplication. The T. hassleriana genome will facilitate future research toward elucidating the evolutionary history of Brassicaceae genomes.
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Brassicaceae/genética , Evolução Molecular , Genoma de Planta/genética , Característica Quantitativa Herdável , Flores/genética , Flores/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Proteínas de Domínio MADS/genética , Proteínas de Domínio MADS/metabolismo , Anotação de Sequência Molecular , Filogenia , Mapeamento Físico do Cromossomo , Poliploidia , Reprodução/genética , Autoincompatibilidade em Angiospermas/genética , Análise de Sequência de DNA , Sintenia/genética , Fatores de TempoRESUMO
FK866 is a specific inhibitor of NAMPT and induces apoptosis of leukemic cells by depletion of intracellular NAD(+). Since up-regulation of NAMPT is associated with several cases of cancers, including leukemias, we asked whether in leukemic cells inhibition of NAMPT involves p53 pathway. We observed that FK866 induced apoptosis and reduced cell proliferation in NB-4, OCI-AML3 and MOLM-13 cell lines. In contrast, the leukemia cell lines, K-562 and Kasumi, containing nonfunctional p53 were relatively unaffected by FK866 treatment. Importantly, direct inhibition of sirtuins significantly reduced the viability of NB-4, OCI-AML3 and MOLM-13 cell lines. Activation of p53 by FK866 involved increased acetylation of p53 at lysine 382 with subsequent increase in the expression of p21 and BAX. Further, knockdown of p53 attenuated the effects of FK866 on apoptosis and cell cycle arrest, which was partly associated with decreased expression of p21 and BAX. Our results suggest the role of p53 acetylation pathway in the anti-leukemic effect of FK866.
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Acrilamidas/farmacologia , Apoptose/efeitos dos fármacos , Citocinas/antagonistas & inibidores , NAD/deficiência , Nicotinamida Fosforribosiltransferase/antagonistas & inibidores , Piperidinas/farmacologia , Proteína Supressora de Tumor p53/metabolismo , Acetilação , Linhagem Celular Tumoral , Proliferação de Células , Inibidor de Quinase Dependente de Ciclina p21/biossíntese , Técnicas de Inativação de Genes , Humanos , Leucemia Mieloide , Sirtuínas/antagonistas & inibidores , Proteína Supressora de Tumor p53/genética , Regulação para Cima/efeitos dos fármacos , Proteína X Associada a bcl-2/biossínteseRESUMO
Inactivation of p53 protein by endogenous and exogenous carcinogens is involved in the pathogenesis of different human malignancies. In cancer associated with SV-40 DNA tumor virus, p53 is considered to be non-functional mainly due to its interaction with the large T-antigen. Using the 293T cell line (HEK293 cells transformed with large T antigen) as a model, we provide evidence that p53 is one of the critical downstream targets involved in FK866-mediated killing of 293T cells. A reduced rate of apoptosis and an increased number of cells in S-phase was accompanied after knockdown of p53 in these cells. Inhibition of NAMPT by FK866, or inhibition of SIRT by nicotinamide decreased proliferation and triggered death of 293T cells involving the p53 acetylation pathway. Additionally, knockdown of p53 attenuated the effect of FK866 on cell proliferation, apoptosis, and cell cycle arrest. The data presented here shed light on two important facts: (1) that p53 in 293T cells is active in the presence of FK866, an inhibitor of NAMPT pathway; (2) the apoptosis induced by FK866 in 293T cells is associated with increased acetylation of p53 at Lys382, which is required for the functional activity of p53.
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Acrilamidas/farmacologia , Apoptose/efeitos dos fármacos , Citocinas/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Neoplasias/metabolismo , Nicotinamida Fosforribosiltransferase/antagonistas & inibidores , Piperidinas/farmacologia , Proteína Supressora de Tumor p53/agonistas , Acetilação , Ciclo Celular , Citocinas/metabolismo , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Lisina/metabolismo , Redes e Vias Metabólicas/efeitos dos fármacos , Neoplasias/enzimologia , Neoplasias/virologia , Nicotinamida Fosforribosiltransferase/metabolismo , Vírus 40 dos Símios , Sirtuína 1/antagonistas & inibidores , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
BACKGROUND AND AIMS: Eschscholzia californica (California poppy) is an emerging model plant for 'evo-devo' studies from the basal eudicot clade of Papaveraceae. California poppy has a relatively small genome, a short life cycle and, most importantly, it is amenable for transformation. However, since this transformation protocol is time consuming, virus-induced gene silencing (VIGS) was evaluated as a fast method to obtain functional data for California poppy genes. METHODS: Commercially available California poppy plants were infiltrated with Agrobacterium tumefaciens carrying the tobacco rattle virus plasmids pTRV1 and pTRV2. pTRV2 contained part of the eschscholzia Phytoene Desaturase (EcPDS) gene whose loss of function results in photobleaching of the green parts of the plant and in a lack of floral coloration. The degree and duration of these symptoms was evaluated for vegetative rosettes and plants in flower. KEY RESULTS: It is shown that VIGS is able to effectively down-regulate the EcPDS gene in eschscholzia. Various degrees of silencing were observed starting <2 weeks after infiltration with Agrobacterium tumefaciens in 92 % of the plants. Tissue with silencing symptoms also showed complete or strong reduction of EcPDS transcripts. Strong silencing resulted in almost completely white petals, fruits, shoots and leaves. Plants with a strong degree of silencing will eventually die off; however, others are able to produce EcPDS gene product even after a strong initial silencing and will recover. Silencing was found to be not always systemic, but was often restricted to certain organs or parts of organs. CONCLUSIONS: VIGS is an effective, fast and transient method to down-regulate gene expression in eschscholzia. It serves well to detect prominent phenotypes which may become obvious even if some target gene transcript remains in the plant tissue. However, subtle phenotypes will be more difficult to detect, as extremely strong silencing effects occur in <10 % of all flowers from infected plants.
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Eschscholzia/genética , Eschscholzia/metabolismo , Regulação da Expressão Gênica de Plantas/fisiologia , Inativação Gênica , Vírus de Plantas/fisiologia , Flores/virologia , Oxirredutases/genética , Oxirredutases/metabolismo , Folhas de Planta/virologiaRESUMO
Cyclin A1 is an alternative A-type cyclin that is essential for spermatogenesis, but it is also expressed in hematopoietic progenitor cells and in acute myeloid leukemia. Its functions during cell cycle progression of somatic cells are incompletely understood. Here, we have analysed the cell cycle functions of cyclin A1 in transformed and nontransformed cells. Murine embryonic fibroblasts derived from cyclin A1-deficient mice were significantly impaired in their proliferative capacity. In accordance, cyclin A1-/- cells accumulated in G1 and G2/M phase while the percentage of S phase cells decreased. Also, lectin stimulated splenic lymphocytes from cyclin A1-/- mice proliferated slower than their wild-type counterparts. Forced cyclin A1 overexpression in NIH3T3 cells and in U937 leukemic cells either by transient transfection or by retroviral infection enhanced S phase entry. Consequently, siRNA mediated silencing of cyclin A1 in highly cyclin A1 expressing ML1 leukemic cells significantly slowed S phase entry, decreased proliferation and inhibited colony formation. Taken together, these analyses demonstrate that cyclin A1 contributes to G1 to S cell cycle progression in somatic cells. Cyclin A1 overexpression enhances S phase entry consistent with an oncogenic function. Finally, cyclin A1 might be a therapeutic target since its silencing inhibited leukemia cell growth.