RESUMO
Pseudomonas aeruginosa is a major human pathogen, particularly effective at colonizing the airways of patients with cystic fibrosis. Bacteriophages are highly abundant at infection sites, but their impact on mammalian immunity remains unclear. We previously showed that Pf4, a temperate filamentous bacteriophage produced by P. aeruginosa, modifies the innate immune response to P. aeruginosa infections via TLR3 signaling, but the underlying mechanisms remained unclear. Notably, Pf4 is a single-stranded DNA and lysogenic phage, and its production does not typically result in lysis of its bacterial host. We identified previously that internalization of Pf4 by human or murine immune cells triggers maladaptive viral pattern recognition receptors and resulted in bacterial persistence based on the presence of phage RNA. We report now that Pf4 phage dampens inflammatory responses to bacterial endotoxin and that this is mediated in part via bacterial vesicles attached to phage particles. Outer membrane vesicles (OMVs) are produced by Gram-negative bacteria and play a key role in host pathogen interaction. Recently, evidence has emerged that OMVs differentially package small RNAs. In this study, we show that Pf4 are decorated with OMVs that remain affixed to Pf4 despite of purification steps. These phages are endocytosed by human cells and delivered to endosomal vesicles. We demonstrate that short RNAs within the OMVs form hairpin structures that trigger TLR3-dependent type I interferon production and antagonize production of antibacterial cytokines and chemokines. In particular, Pf4 phages inhibit CXCL5, preventing efficient neutrophil chemotaxis in response to endotoxin. Moreover, blocking IFNAR or TLR3 signaling abrogates the effect of Pf4 bound to OMVs on macrophage activation. In a murine acute pneumonia model, mice treated with Pf4 associated with OMVs show significantly less neutrophil infiltration in BAL fluid than mice treated with purified Pf4. These changes in macrophage phenotype are functionally relevant: conditioned media from cells exposed to Pf4 decorated with OMVs are significantly less effective at inducing neutrophil migration in vitro and in vivo. These results suggest that Pf4 phages alter innate immunity to bacterial endotoxin and OMVs, potentially dampening inflammation at sites of bacterial colonization or infection.
Assuntos
Bacteriófagos , Infecções por Pseudomonas , Humanos , Animais , Camundongos , Neutrófilos/metabolismo , Membrana Externa Bacteriana/metabolismo , Receptor 3 Toll-Like , Infecções por Pseudomonas/microbiologia , Endotoxinas , MamíferosRESUMO
OBJECTIVES: Striking disparities in access to radiation therapy (RT) exist, especially among racial and ethnic-minority patients. We analyzed census block group data to evaluate differences in travel distance to RT as a function of race and ethnicity, socioeconomic status, and rurality. METHODS: The Directory of Radiotherapy Centers provided the addresses of facilities containing linear accelerators for RT. We classified block groups as majority (≥ 50%) American Indian/Alaska Native (AI/AN), black, white, Asian, no single racial majority, or Hispanic regardless of race. We used the Area Deprivation Index to classify deprivation and Rural-Urban Commuting Area codes to classify rurality. Generalized linear mixed models tested associations between these factors and distance to nearest RT facility. RESULTS: Median distance to nearest RT facility was 72 miles in AI/AN-majority block groups, but 4 to 7 miles in block groups with non-AI/AN majorities. Multivariable models estimated that travel distances in AI/AN-majority block groups were 39 to 41 miles longer than in areas with non-AI/AN majorities. Travel distance was 1.3 miles longer in the more deprived areas versus less deprived areas and 16 to 32 miles longer in micropolitan, small town, and rural areas versus metropolitan areas. CONCLUSIONS: Cancer patients in block groups with AI/AN-majority populations, nonmetropolitan location, and low socioeconomic status experience substantial travel disparities in access to RT. Future research with more granular community- and individual-level data should explore the many other known barriers to access to cancer care and their relationship to the barriers posed by distance to RT care.
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Etnicidade , Humanos , Estados Unidos , Disparidades em Assistência à Saúde , Acessibilidade aos Serviços de Saúde , População RuralRESUMO
To investigate the pathogenesis of a congenital form of hepatic fibrosis, human hepatic organoids were engineered to express the most common causative mutation for Autosomal Recessive Polycystic Kidney Disease (ARPKD). Here we show that these hepatic organoids develop the key features of ARPKD liver pathology (abnormal bile ducts and fibrosis) in only 21 days. The ARPKD mutation increases collagen abundance and thick collagen fiber production in hepatic organoids, which mirrors ARPKD liver tissue pathology. Transcriptomic and other analyses indicate that the ARPKD mutation generates cholangiocytes with increased TGFß pathway activation, which are actively involved stimulating myofibroblasts to form collagen fibers. There is also an expansion of collagen-producing myofibroblasts with markedly increased PDGFRB protein expression and an activated STAT3 signaling pathway. Moreover, the transcriptome of ARPKD organoid myofibroblasts resemble those present in commonly occurring forms of liver fibrosis. PDGFRB pathway involvement was confirmed by the anti-fibrotic effect observed when ARPKD organoids were treated with PDGFRB inhibitors. Besides providing insight into the pathogenesis of congenital (and possibly acquired) forms of liver fibrosis, ARPKD organoids could also be used to test the anti-fibrotic efficacy of potential anti-fibrotic therapies.
Assuntos
Cirrose Hepática/patologia , Modelos Biológicos , Organoides/patologia , Doenças dos Ductos Biliares/genética , Doenças dos Ductos Biliares/metabolismo , Doenças dos Ductos Biliares/patologia , Colágeno/metabolismo , Células Epiteliais/patologia , Humanos , Células-Tronco Pluripotentes Induzidas/citologia , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Cirrose Hepática/tratamento farmacológico , Cirrose Hepática/genética , Cirrose Hepática/metabolismo , Mutação , Miofibroblastos/metabolismo , Miofibroblastos/patologia , Organoides/efeitos dos fármacos , Organoides/metabolismo , Rim Policístico Autossômico Recessivo/tratamento farmacológico , Rim Policístico Autossômico Recessivo/genética , Rim Policístico Autossômico Recessivo/metabolismo , Rim Policístico Autossômico Recessivo/patologia , Receptor beta de Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais , Fator de Crescimento Transformador beta/metabolismoRESUMO
Prolonged treatments for the destaining of teeth using high concentrations of hydrogen peroxide may cause secondary unwanted effects such as tooth hypersensitivity and gingival irritation. Hence, it is aimed to develop a non-peroxide-based method to oxidize iron-tannate (Fe-TA) stained hydroxyapatite (HAp) and bovine enamel (BE) samples. Constant current electrolysis (CCE) experiments were carried out on Pt working electrode in aqueous NaCl, KCl and KI solutions at discrete concentrations under continuous experiment and a non-continuous experiment. CCE shows that in the presence of iron tannate (Fe-TA) stained HAP, approximately 30 ppm of iodine was generated using 0.1M KI and nearly 40 ppm was produced with 0.2 M KI. By using a non-continuous CCE process, the lowest amount of chlorine was generated from NaCl solution, which was well within the safety limits for oral applications. Depending on the experimental conditions used, between 13 ppm and 124 ppm of chlorine was generated. CCE of Fe-TA stained on HAp using KCl reveals that at the lowest current density of 10 mA/cm2, the amount of hypochlorite generated was 20 ppm on Pt electrode having a surface area of 6 cm2. Ion chromatographic (IC) analysis revealed that non-continuous CCE of Fe-TA-BE in NaCl generated a low concentration of sodium perchlorate (0.8 ppm), whereas the continuous process generated no perchlorate, but a considerable higher quantity of chlorate for Fe-TA-BE (37 ppm) and Fe-TA-HAp (140 ppm) samples.
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Glioblastoma is a fatal disease in which most targeted therapies have clinically failed. However, pharmacological reactivation of tumour suppressors has not been thoroughly studied as yet as a glioblastoma therapeutic strategy. Tumour suppressor protein phosphatase 2A is inhibited by non-genetic mechanisms in glioblastoma, and thus, it would be potentially amendable for therapeutic reactivation. Here, we demonstrate that small molecule activators of protein phosphatase 2A, NZ-8-061 and DBK-1154, effectively cross the in vitro model of blood-brain barrier, and in vivo partition to mouse brain tissue after oral dosing. In vitro, small molecule activators of protein phosphatase 2A exhibit robust cell-killing activity against five established glioblastoma cell lines, and nine patient-derived primary glioma cell lines. Collectively, these cell lines have heterogeneous genetic background, kinase inhibitor resistance profile and stemness properties; and they represent different clinical glioblastoma subtypes. Moreover, small molecule activators of protein phosphatase 2A were found to be superior to a range of kinase inhibitors in their capacity to kill patient-derived primary glioma cells. Oral dosing of either of the small molecule activators of protein phosphatase 2A significantly reduced growth of infiltrative intracranial glioblastoma tumours. DBK-1154, with both higher degree of brain/blood distribution, and more potent in vitro activity against all tested glioblastoma cell lines, also significantly increased survival of mice bearing orthotopic glioblastoma xenografts. In summary, this report presents a proof-of-principle data for blood-brain barrier-permeable tumour suppressor reactivation therapy for glioblastoma cells of heterogenous molecular background. These results also provide the first indications that protein phosphatase 2A reactivation might be able to challenge the current paradigm in glioblastoma therapies which has been strongly focused on targeting specific genetically altered cancer drivers with highly specific inhibitors. Based on demonstrated role for protein phosphatase 2A inhibition in glioblastoma cell drug resistance, small molecule activators of protein phosphatase 2A may prove to be beneficial in future glioblastoma combination therapies.
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Glioblastoma (GBM) is a malignant brain tumor with few therapeutic options. The disease presents with a complex spectrum of genomic aberrations, but the pharmacological consequences of these aberrations are partly unknown. Here, we report an integrated pharmacogenomic analysis of 100 patient-derived GBM cell cultures from the human glioma cell culture (HGCC) cohort. Exploring 1,544 drugs, we find that GBM has two main pharmacological subgroups, marked by differential response to proteasome inhibitors and mutually exclusive aberrations in TP53 and CDKN2A/B. We confirm this trend in cell and in xenotransplantation models, and identify both Bcl-2 family inhibitors and p53 activators as potentiators of proteasome inhibitors in GBM cells. We can further predict the responses of individual cell cultures to several existing drug classes, presenting opportunities for drug repurposing and design of stratified trials. Our functionally profiled biobank provides a valuable resource for the discovery of new treatments for GBM.
Assuntos
Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Terapia de Alvo Molecular , Medicina de Precisão , Animais , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Bortezomib/farmacologia , Proliferação de Células/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p15/genética , Inibidor p16 de Quinase Dependente de Ciclina/genética , Redes Reguladoras de Genes/efeitos dos fármacos , Heterogeneidade Genética , Genoma Humano , Glioblastoma/genética , Humanos , Camundongos Endogâmicos BALB C , Mutação/genética , Inibidores de Proteassoma/farmacologia , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/metabolismoRESUMO
Glioblastoma multiforme continues to have a dismal prognosis. Even though detailed information on the genetic aberrations in cell signaling and cell-cycle checkpoint control is available, no effective targeted treatment has been developed. Despite the advanced molecular defects, glioblastoma cells may have remnants of normal growth-inhibitory pathways, such as the bone morphogenetic protein (BMP) signaling pathway. We have evaluated the growth-inhibitory effect of BMP4 across a broad spectrum of patient samples, using a panel of 40 human glioblastoma initiating cell (GIC) cultures. A wide range of responsiveness was observed. BMP4 sensitivity was positively correlated with a proneural mRNA expression profile, high SOX2 activity, and BMP4-dependent upregulation of genes associated with inhibition of the MAPK pathway, as demonstrated by gene set enrichment analysis. BMP4 response in sensitive cells was mediated by the canonical BMP receptor pathway involving SMAD1/5/9 phosphorylation and SMAD4 expression. SOX2 was consistently downregulated in BMP4-treated cells. Forced expression of SOX2 attenuated the BMP4 sensitivity including a reduced upregulation of MAPK-inhibitory genes, implying a functional relationship between SOX2 downregulation and sensitivity. The results show an extensive heterogeneity in BMP4 responsiveness among GICs and identify a BMP4-sensitive subgroup, in which SOX2 is a mediator of the response. IMPLICATIONS: Development of agonists targeting the BMP signaling pathway in glioblastoma is an attractive avenue toward a better treatment. Our study may help find biomarkers that predict the outcome of such treatment and enable stratification of patients.
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Proteína Morfogenética Óssea 4/metabolismo , Neoplasias Encefálicas/metabolismo , Glioblastoma/metabolismo , Fatores de Transcrição SOXB1/metabolismo , Proteína Morfogenética Óssea 4/farmacologia , Neoplasias Encefálicas/genética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Glioblastoma/genética , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Fatores de Transcrição SOXB1/genética , Regulação para Cima/efeitos dos fármacosRESUMO
BACKGROUND: The mortality benefits of meeting the US federal guidelines for physical activity, which includes recommendations for both aerobic and muscle-strengthening activities, have never been examined among smokers. Our aim was to investigate the association between reporting to meet the guidelines and all-cause, cancer, cardiovascular disease, and respiratory disease mortality among smokers. METHODS: We pooled data from the 1998-2009 National Health Interview Survey, which were linked to records in the National Death Index (n = 68,706). Hazard ratios (HR) were computed to estimate the effect of meeting the physical activity guidelines on mortality. RESULTS: Smokers who reported meeting the guidelines for physical activity had 29% lower risk of all-cause mortality (HR: 0.71; 95% confidence interval [CI], 0.62-0.81), 46% lower risk of mortality from cardiovascular disease (HR: 0.54; 95% CI, 0.39-0.76), and 26% lower risk of mortality from cancer (HR: 0.74; 95% CI, 0.59-0.93), compared with those who reported meeting neither the aerobic nor the muscle-strengthening recommendations of the guidelines. Meeting the aerobic recommendation of the guidelines was associated with a 42% decline in that risk (HR: 0.58; 95% CI, 0.44-0.77). CONCLUSION: Smokers who adhere to physical activity guidelines show a significant reduction in mortality.
Assuntos
Doenças Cardiovasculares/mortalidade , Exercício Físico , Fidelidade a Diretrizes/estatística & dados numéricos , Neoplasias/mortalidade , Doenças Respiratórias/mortalidade , Fumantes/estatística & dados numéricos , Fumar/efeitos adversos , Adulto , Idoso , Terapia por Exercício/métodos , Feminino , Humanos , Entrevistas como Assunto , Masculino , Pessoa de Meia-Idade , Risco , Fatores de Risco , Comportamento de Redução do Risco , Inquéritos e Questionários , Estados Unidos/epidemiologiaRESUMO
OBJECTIVES: Genetic variations in TNFAIP3 (A20) de-ubiquitinase (DUB) domain increase the risk of systemic lupus erythematosus (SLE) and rheumatoid arthritis. A20 is a negative regulator of NF-κB but the role of its DUB domain and related genetic variants remain unclear. We aimed to study the functional effects of A20 DUB-domain alterations in immune cells and understand its link to SLE pathogenesis. METHODS: CRISPR/Cas9 was used to generate human U937 monocytes with A20 DUB-inactivating C103A knock-in (KI) mutation. Whole genome RNA-sequencing was used to identify differentially expressed genes between WT and C103A KI cells. Functional studies were performed in A20 C103A U937 cells and in immune cells from A20 C103A mice and genotyped healthy individuals with A20 DUB polymorphism rs2230926. Neutrophil extracellular trap (NET) formation was addressed ex vivo in neutrophils from A20 C103A mice and SLE-patients with rs2230926. RESULTS: Genetic disruption of A20 DUB domain in human and murine myeloid cells did not give rise to enhanced NF-κB signalling. Instead, cells with C103A mutation or rs2230926 polymorphism presented an upregulated expression of PADI4, an enzyme regulating protein citrullination and NET formation, two key mechanisms in autoimmune pathology. A20 C103A cells exhibited enhanced protein citrullination and extracellular trap formation, which could be suppressed by selective PAD4 inhibition. Moreover, SLE-patients with rs2230926 showed increased NETs and increased frequency of autoantibodies to citrullinated epitopes. CONCLUSIONS: We propose that genetic alterations disrupting the A20 DUB domain mediate increased susceptibility to SLE through the upregulation of PADI4 with resultant protein citrullination and extracellular trap formation.
Assuntos
Citrulinação/genética , Endopeptidases/genética , Armadilhas Extracelulares/genética , Lúpus Eritematoso Sistêmico/genética , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/genética , Animais , Autoanticorpos/sangue , Autoanticorpos/imunologia , Epitopos/imunologia , Predisposição Genética para Doença/genética , Humanos , Lúpus Eritematoso Sistêmico/sangue , Camundongos , NF-kappa B/metabolismo , Neutrófilos/metabolismo , Polimorfismo Genético , Proteína-Arginina Desiminase do Tipo 4/metabolismo , Regulação para Cima/genéticaRESUMO
PURPOSE: Using the RE-AIM framework, the primary purpose of this qualitative study was to conduct focus groups to identify areas for future adaptation of an evidence-based cardiovascular disease (CVD) risk intervention (COACH) developed for an urban primary care setting to urban American Indian (AI)-serving settings. METHODS: This qualitative study involved conducting three focus groups with 31 urban AI patients with two or more CVD risk factors to maximize reach and efficacy of COACH. The patients had not yet participated in an adapted COACH program. RESULTS: Findings from the focus groups indicate that a culturally adapted CVD risk reduction program modeled after COACH would be acceptable among urban AI populations. Recommendations for cultural adaptation include a need for images of AI people, traditional AI exercise activities and AI foods, information on the portion sizes of traditional foods, and expanded information on tobacco use and resources. CONCLUSION: With cultural adaptations, the COACH program can be pilot-tested in urban AI-serving primary care settings to address health concerns and behaviors that affect cardiovascular health outcomes.
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Doenças Cardiovasculares/prevenção & controle , Indígenas Norte-Americanos , Comportamento de Redução do Risco , Adulto , Idoso , Doenças Cardiovasculares/etnologia , Prática Clínica Baseada em Evidências/métodos , Feminino , Grupos Focais , Humanos , Masculino , Pessoa de Meia-Idade , Desenvolvimento de Programas/métodos , Fatores de Risco , População UrbanaRESUMO
MOTIVATION: Medulloblastoma (MB) is a brain cancer predominantly arising in children. Roughly 70% of patients are cured today, but survivors often suffer from severe sequelae. MB has been extensively studied by molecular profiling, but often in small and scattered cohorts. To improve cure rates and reduce treatment side effects, accurate integration of such data to increase analytical power will be important, if not essential. RESULTS: We have integrated 23 transcription datasets, spanning 1350 MB and 291 normal brain samples. To remove batch effects, we combined the Removal of Unwanted Variation (RUV) method with a novel pipeline for determining empirical negative control genes and a panel of metrics to evaluate normalization performance. The documented approach enabled the removal of a majority of batch effects, producing a large-scale, integrative dataset of MB and cerebellar expression data. The proposed strategy will be broadly applicable for accurate integration of data and incorporation of normal reference samples for studies of various diseases. We hope that the integrated dataset will improve current research in the field of MB by allowing more large-scale gene expression analyses. AVAILABILITY AND IMPLEMENTATION: The RUV-normalized expression data is available through the Gene Expression Omnibus (GEO; https://www.ncbi.nlm.nih.gov/geo/) and can be accessed via the GSE series number GSE124814. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.
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Neoplasias Cerebelares , Meduloblastoma , Expressão Gênica , Perfilação da Expressão Gênica , HumanosRESUMO
BACKGROUND: Agriculture workers are exposed to microbial component- and particulate matter-enriched organic dust aerosols. Whereas it is clear that exposure to these aerosols can lead to lung inflammation, it is not known how inflammatory responses are resolved in some individuals while others develop chronic lung disease. Interleukin (IL)-10 is an immunomodulatory cytokine that is recognized as a potent anti-inflammatory and pro-resolving factor. The objective of this study was to determine whether there is a relationship of systemic IL-10 and proinflammatory responses and/or respiratory health effects in humans with prior agriculture exposure. METHODS: This is a cross sectional study of 625 veterans with > 2 years of farming experience. Whole blood was stimulated with or without organic dust and measured for IL-6, TNFα and IL-10. Participants underwent spirometry and respiratory symptoms were assessed by questionnaire. RESULTS: We found that baseline IL-10 concentration from the whole blood assay was inversely associated with ΔTNF-α (r = - 0.63) and ΔIL-6 (r = - 0.37) levels. Results remained highly significant in the linear regression model after adjusting for age, sex, BMI, race, education, smoking status, and white blood cell count (ΔTNF-α, p < 0.0001; ΔIL-6, p < 0.0001). We found no association between chronic cough (p = 0.18), chronic phlegm (p = 0.31) and chronic bronchitis (p = 0.06) and baseline IL-10 levels using univariate logistic regression models. However, we did find that higher FEV1/FVC was significantly associated with increased baseline IL-10 concentration. CONCLUSIONS: Collectively, these studies support a potential role for IL-10 in modulating an inflammatory response and lung function in agriculture-exposed persons.
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Agricultura/tendências , Citocinas/sangue , Poeira , Interleucina-10/sangue , Pneumopatias/sangue , Exposição Ocupacional/efeitos adversos , Idoso , Biomarcadores/sangue , Estudos de Coortes , Estudos Transversais , Feminino , Humanos , Mediadores da Inflamação/sangue , Pneumopatias/diagnóstico , Pneumopatias/epidemiologia , Masculino , Pessoa de Meia-Idade , Testes de Função Respiratória/métodosRESUMO
We describe the impact of the Adolescent Health Project on sexually transmitted infection (STI) testing in Omaha, NE, during phase 1 (media campaigns) and phase 2 (free STI testing). To assess the impact of each phase on STI testing, we examined monthly data from January 2013 to April 2017 via interrupted time series analyses. There was an immediate and statistically significant increase in testing during phase 2. Expanding and advertising free STI testing is a promising approach to increasing testing.
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Saúde do Adolescente/estatística & dados numéricos , Serviços de Saúde Comunitária/métodos , Programas de Rastreamento/estatística & dados numéricos , Infecções Sexualmente Transmissíveis/epidemiologia , Adolescente , Adulto , Feminino , Humanos , Masculino , Nebraska/epidemiologia , Infecções Sexualmente Transmissíveis/diagnóstico , Infecções Sexualmente Transmissíveis/prevenção & controle , Adulto JovemRESUMO
BACE1 is responsible for the first step in APP proteolysis, leading to toxic Aß production, and has been indicated to play a key role in the pathogenesis of Alzheimer's disease. The related isoform BACE2 is thought to be involved in processing of the pigment cell-specific melanocyte protein. To avoid potential effects on pigmentation, we investigated the feasibility for developing isoform-selective BACE1 inhibitors. Cocrystal structures of 47 compounds were analyzed and clustered according to their selectivity profiles. Selective BACE1 inhibitors were found to exhibit two distinct conformational features proximal to the flap and the S3 subpocket. Several new molecules were designed and tested to make use of this observation. The combination of a pyrimidinyl C-ring and a methylcyclohexyl element resulted in lead molecule 28, which exhibited â¼50-fold selectivity. Compared to a nonselective BACE1/2 inhibitor, 28 showed significantly less inhibition of PMEL processing in human melanocytes, indicating good functional selectivity of this inhibitor class.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Inibidores de Proteases/farmacologia , Secretases da Proteína Precursora do Amiloide/química , Peptídeos beta-Amiloides/metabolismo , Animais , Ácido Aspártico Endopeptidases/química , Encéfalo/metabolismo , Domínio Catalítico , Cães , Feminino , Humanos , Células Madin Darby de Rim Canino , Masculino , Camundongos Endogâmicos C57BL , Estrutura Molecular , Oxazóis/síntese química , Oxazóis/química , Oxazóis/farmacocinética , Oxazóis/farmacologia , Fragmentos de Peptídeos/metabolismo , Inibidores de Proteases/síntese química , Inibidores de Proteases/química , Inibidores de Proteases/farmacocinética , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/química , Ratos , Compostos de Espiro/síntese química , Compostos de Espiro/química , Compostos de Espiro/farmacocinética , Compostos de Espiro/farmacologia , Relação Estrutura-Atividade , Antígeno gp100 de Melanoma/metabolismoRESUMO
Production and secretion of pro-metastatic proteins is a feature of many tumor cells. The FAM3C interleukin-like epithelial-to-mesenchymal-transition (EMT) inducer (ILEI) has been shown to be strongly up-regulated in several cancers and to be essential for tumor formation and metastasis in epithelial cells, correlating with a significant decrease in overall survival in colon and breast cancer patients. ILEI has been seen to interact with the γ-secretase presenilin 1 subunit (PS1). However, not much is known about the mechanism-of-action or the detailed ILEI structure. We present here the crystal structures of FAM3C ILEI and show that it exists as monomers but also as covalent dimers. The observed ILEI ß-ß-α fold confirmed previous indications that the FAM3C proteins do not form classical four-helix-bundle structures as was initially predicted. This provides the first experimental evidence that the interleukin-like EMT inducers are not evolutionarily related to the interleukins. However, more surprisingly, the ILEI dimer structure was found to feature a trans-linked domain swap, converting an intramolecular disulfide to intermolecular. Interestingly, dimeric but not monomeric ILEI was subsequently found to cause a dose-dependent increase in EpRas cell invasiveness comparable with TGF-ß, indicating that the dimer might be the active ILEI species. This is in line with a parallel study showing that covalent oligomerization of ILEI is essential for EMT and tumor progression in vivo The structures and the activity data give some first insight into the relationship between dimerization and ILEI function as well as indicate an intriguing link between ILEI, the PS1-protease, TGF-ß, and the TGF-ß receptor 1.
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Citocinas/metabolismo , Modelos Moleculares , Proteínas de Neoplasias/metabolismo , Substituição de Aminoácidos , Animais , Linhagem Celular Transformada , Movimento Celular , Cristalografia por Raios X , Cisteína/química , Cistina/química , Citocinas/química , Citocinas/genética , Dimerização , Humanos , Interleucinas/química , Interleucinas/metabolismo , Camundongos , Proteínas de Neoplasias/química , Proteínas de Neoplasias/genética , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Mutação Puntual , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Estabilidade Proteica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/metabolismo , Homologia Estrutural de ProteínaRESUMO
Protease-activated receptors (PARs) are a family of G-protein-coupled receptors (GPCRs) that are irreversibly activated by proteolytic cleavage of the N terminus, which unmasks a tethered peptide ligand that binds and activates the transmembrane receptor domain, eliciting a cellular cascade in response to inflammatory signals and other stimuli. PARs are implicated in a wide range of diseases, such as cancer and inflammation. PARs have been the subject of major pharmaceutical research efforts but the discovery of small-molecule antagonists that effectively bind them has proved challenging. The only marketed drug targeting a PAR is vorapaxar, a selective antagonist of PAR1 used to prevent thrombosis. The structure of PAR1 in complex with vorapaxar has been reported previously. Despite sequence homology across the PAR isoforms, discovery of PAR2 antagonists has been less successful, although GB88 has been described as a weak antagonist. Here we report crystal structures of PAR2 in complex with two distinct antagonists and a blocking antibody. The antagonist AZ8838 binds in a fully occluded pocket near the extracellular surface. Functional and binding studies reveal that AZ8838 exhibits slow binding kinetics, which is an attractive feature for a PAR2 antagonist competing against a tethered ligand. Antagonist AZ3451 binds to a remote allosteric site outside the helical bundle. We propose that antagonist binding prevents structural rearrangements required for receptor activation and signalling. We also show that a blocking antibody antigen-binding fragment binds to the extracellular surface of PAR2, preventing access of the tethered ligand to the peptide-binding site. These structures provide a basis for the development of selective PAR2 antagonists for a range of therapeutic uses.
Assuntos
Receptor PAR-2/química , Receptor PAR-2/metabolismo , Regulação Alostérica/efeitos dos fármacos , Sítio Alostérico/efeitos dos fármacos , Anticorpos Bloqueadores/química , Anticorpos Bloqueadores/farmacologia , Benzimidazóis/química , Benzimidazóis/farmacologia , Benzodioxóis/química , Benzodioxóis/farmacologia , Álcoois Benzílicos/química , Álcoois Benzílicos/farmacologia , Cristalografia por Raios X , Humanos , Imidazóis/química , Imidazóis/farmacologia , Fragmentos Fab das Imunoglobulinas/química , Fragmentos Fab das Imunoglobulinas/farmacologia , Cinética , Ligantes , Modelos Moleculares , Receptor PAR-2/antagonistas & inibidores , Transdução de Sinais/efeitos dos fármacosRESUMO
Glioblastoma multiforme (GBM, astrocytoma grade IV) is the most common malignant primary brain tumor in adults. Addressing the shortage of effective treatment options for this cancer, we explored repurposing of existing drugs into combinations with potent activity against GBM cells. We report that the phytoalexin pterostilbene is a potentiator of two drugs with previously reported anti-GBM activity, the EGFR inhibitor gefitinib and the antidepressant sertraline. Combinations of either of these two compounds with pterostilbene suppress cell growth, viability, sphere formation and inhibit migration in tumor GBM cell (GC) cultures. The potentiating effect of pterostilbene was observed to a varying degree across a panel of 41 patient-derived GCs, and correlated in a case specific manner with the presence of missense mutation of EGFR and PIK3CA and a focal deletion of the chromosomal region 1p32. We identify pterostilbene-induced cell cycle arrest, synergistic inhibition of MAPK activity and induction of Thioredoxin interacting protein (TXNIP) as possible mechanisms behind pterostilbene's effect. Our results highlight a nontoxic stilbenoid compound as a modulator of anticancer drug response, and indicate that pterostilbene might be used to modulate two anticancer compounds in well-defined sets of GBM patients.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Estilbenos/farmacologia , Idoso , Idoso de 80 Anos ou mais , Antineoplásicos Fitogênicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/patologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Variações do Número de Cópias de DNA , Sinergismo Farmacológico , Feminino , Gefitinibe , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Mutação , Fenótipo , Inibidores de Proteínas Quinases/farmacologia , Quinazolinas/farmacologia , Estilbenos/uso terapêutico , TranscriptomaRESUMO
Glioblastomas are characterized by transcriptionally distinct subtypes, but despite possible clinical relevance, their regulation remains poorly understood. The commonly used molecular classification systems for GBM all identify a subtype with high expression of mesenchymal marker transcripts, strongly associated with invasive growth. We used a comprehensive data-driven network modeling technique (augmented sparse inverse covariance selection, aSICS) to define separate genomic, epigenetic, and transcriptional regulators of glioblastoma subtypes. Our model identified Annexin A2 (ANXA2) as a novel methylation-controlled positive regulator of the mesenchymal subtype. Subsequent evaluation in two independent cohorts established ANXA2 expression as a prognostic factor that is dependent on ANXA2 promoter methylation. ANXA2 knockdown in primary glioblastoma stem cell-like cultures suppressed known mesenchymal master regulators, and abrogated cell proliferation and invasion. Our results place ANXA2 at the apex of a regulatory cascade that determines glioblastoma mesenchymal transformation and validate aSICS as a general methodology to uncover regulators of cancer subtypes.
Assuntos
Anexina A2/metabolismo , Epigênese Genética , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Glioblastoma/metabolismo , Mesenquimoma/genética , Mesenquimoma/metabolismo , Algoritmos , Anexina A2/genética , Biomarcadores Tumorais , Linhagem Celular Tumoral , Biologia Computacional/métodos , Metilação de DNA , Bases de Dados de Ácidos Nucleicos , Transição Epitelial-Mesenquimal , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Glioblastoma/mortalidade , Glioblastoma/patologia , Humanos , Mesenquimoma/mortalidade , Mesenquimoma/patologia , Anotação de Sequência Molecular , Gradação de Tumores , Células-Tronco Neoplásicas/metabolismo , Prognóstico , Regiões Promotoras GenéticasRESUMO
Excited state proton transfer studies of six Ru polypyridyl compounds with carboxylic acid/carboxylate group(s) revealed that some were photoacids and some were photobases. The compounds [Ru(II)(btfmb)2(LL)](2+), [Ru(II)(dtb)2(LL)](2+), and [Ru(II)(bpy)2(LL)](2+), where bpy is 2,2'-bipyridine, btfmb is 4,4'-(CF3)2-bpy, and dtb is 4,4'-((CH3)3C)2-bpy, and LL is either dcb = 4,4'-(CO2H)2-bpy or mcb = 4-(CO2H),4'-(CO2Et)-2,2'-bpy, were synthesized and characterized. The compounds exhibited intense metal-to-ligand charge-transfer (MLCT) absorption bands in the visible region and room temperature photoluminescence (PL) with long τ > 100 ns excited state lifetimes. The mcb compounds had very similar ground state pKa's of 2.31 ± 0.07, and their characterization enabled accurate determination of the two pKa values for the commonly utilized dcb ligand, pKa1 = 2.1 ± 0.1 and pKa2 = 3.0 ± 0.2. Compounds with the btfmb ligand were photoacidic, and the other compounds were photobasic. Transient absorption spectra indicated that btfmb compounds displayed a [Ru(III)(btfmb(-))L2](2+)* localized excited state and a [Ru(III)(dcb(-))L2](2+)* formulation for all the other excited states. Time dependent PL spectral shifts provided the first kinetic data for excited state proton transfer in a transition metal compound. PL titrations, thermochemical cycles, and kinetic analysis (for the mcb compounds) provided self-consistent pKa* values. The ability to make a single ionizable group photobasic or photoacidic through ligand design was unprecedented and was understood based on the orientation of the lowest-lying MLCT excited state dipole relative to the ligand that contained the carboxylic acid group(s).
RESUMO
Glioblastoma (GBM) is the most frequent and malignant form of primary brain tumor. GBM is essentially incurable and its resistance to therapy is attributed to a subpopulation of cells called glioma stem cells (GSCs). To meet the present shortage of relevant GBM cell (GC) lines we developed a library of annotated and validated cell lines derived from surgical samples of GBM patients, maintained under conditions to preserve GSC characteristics. This collection, which we call the Human Glioblastoma Cell Culture (HGCC) resource, consists of a biobank of 48 GC lines and an associated database containing high-resolution molecular data. We demonstrate that the HGCC lines are tumorigenic, harbor genomic lesions characteristic of GBMs, and represent all four transcriptional subtypes. The HGCC panel provides an open resource for in vitro and in vivo modeling of a large part of GBM diversity useful to both basic and translational GBM research.