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Antiangiogenic agents attenuate tumours' growth and metastases and are therefore beneficial as an adjuvant or standalone cancer regimen. Drugs with dual antiproliferative and antiangiogenic activities can achieve anticancer efficacy and overcome acquired resistance. In this study, synthetic flavones (5a,b) with reported anticancer activity, and derivatives (4b and 6a), exhibited significant inhibition of endothelial cell tube formation (40-55%, 12 h) at 1 µM, which is comparable to sunitinib (50% inhibition at 1 µM, 48 h). Flavones (4b, 5a,b and 6a) also showed 25-37% reduction in HUVECs migration at 10 µM. In a Western blotting assay, 5a and 5b subdued VEGFR2 phosphorylation by 37% and 57%, respectively, suggesting that VEGFR2 may be their main antiangiogenic target. 5b displayed the best docking fit with VEGFR2 in an in silico study, followed by 5a, emphasizing the importance of the 7-hydroxyl group accompanied by a 4-C=S for activity. Conversely, derivatives with a 4-carbonyl moiety fitted poorly into the target's binding pocket, suggesting that their antiangiogenic activity depends on a different target. This study provides valuable insight into the Structure Activity Relationships (SAR) and modes of action of halogenated flavones with VEGFR2 and highlights their therapeutic potential as antiangiogenic/anticancer lead compounds.
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Antineoplásicos , Flavonas , Inibidores da Angiogênese/química , Inibidores da Angiogênese/farmacologia , Antineoplásicos/farmacologia , Proliferação de Células , Células Endoteliais/metabolismo , Flavonas/química , Flavonas/farmacologia , Flavonoides/farmacologia , Fosforilação , Receptor 2 de Fatores de Crescimento do Endotélio VascularRESUMO
EfeUOB/M has been characterised in Pseudomonas syringae pathovar. syringae as a novel type of ferrous-iron transporter, consisting of an inner-membrane protein (EfeUPsy) and three periplasmic proteins (EfeOPsy, EfeMPsy and EfeBPsy). The role of an iron permease and peroxidase function has been identified for the EfeU and EfeB proteins, respectively, but the role of EfeO/M remains unclear. EfeMPsy is an 'M75-only' EfeO-like protein with a C-terminal peptidase-M75 domain (EfeOII/EfeM family). Herein, we report the 1.6 Å resolution crystal structure of EfeMPsy, the first structural report for an EfeM component of P. syringae pv. syringae. The structure possesses the bi-lobate architecture found in other bacterial periplasmic substrate/solute binding proteins. Metal binding studies, using SRCD and ICP-OES, reveal a preference of EfeMPsy for copper, iron and zinc. This work provides detailed knowledge of the structural scaffold, the metal site geometry, and the divalent metal binding potential of EfeM. This work provides crucial underpinning for a more detailed understanding of the role of EfeM/EfeO proteins and the peptidase-M75 domains in EfeUOB/M iron uptake systems in bacteria.
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Ferro , Pseudomonas syringae , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Cristalografia por Raios X , Transporte de Íons , Ferro/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Peptídeo Hidrolases/metabolismo , Pseudomonas syringae/metabolismoRESUMO
The renin-angiotensin system (RAS) is a key regulator of blood pressure and hypertension. Angiotensin-converting enzyme 2 (ACE2) and angiotensin-converting enzyme I (ACE) are two main components of the RAS that play a major role in blood pressure homeostasis. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses ACE2 as a receptor to enter cells. Despite some controversies, numerous studies have reported a significant association between the use of ACE inhibitors and reduced risk of COVID-19. In our previous studies, we produced and identified peptide sequences present in whey hydrolysates exhibiting high ACE inhibitory activity. Therefore, the aim of this work is to obtain an improved understanding of the function of these natural peptides as RAS inhibitors and investigate their potential therapeutic role in the COVID-19 pandemic. The molecular interactions between peptides IPP, LIVTQ, IIAE, LVYPFP, and human ACE2 were assessed by employing a molecular docking approach. The results show that natural whey-derived peptides have a dual inhibitory action against both ACE and ACE2. This dual activity distinguishes these ACE inhibitory peptides from synthetic drugs, such as Captopril and Lisinopril which were not shown to inhibit ACE2 activity, and may represent a potential strategy in the treatment of COVID-19.
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Enzima de Conversão de Angiotensina 2/metabolismo , Tratamento Farmacológico da COVID-19 , Peptídeos/química , Peptídeos/farmacologia , Enzima de Conversão de Angiotensina 2/química , Inibidores da Enzima Conversora de Angiotensina/química , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Antivirais/química , Antivirais/farmacologia , Humanos , Simulação de Acoplamento Molecular , Peptídeos/metabolismo , Peptidil Dipeptidase A/química , Sistema Renina-Angiotensina/efeitos dos fármacos , Proteínas do Soro do Leite/químicaRESUMO
Herbarium sheets present a unique view of the world's botanical history, evolution, and biodiversity. This makes them an all-important data source for botanical research. With the increased digitization of herbaria worldwide and advances in the domain of fine-grained visual classification which can facilitate automatic identification of herbarium specimen images, there are many opportunities for supporting and expanding research in this field. However, existing datasets are either too small, or not diverse enough, in terms of represented taxa, geographic distribution, and imaging protocols. Furthermore, aggregating datasets is difficult as taxa are recognized under a multitude of names and must be aligned to a common reference. We introduce the Herbarium 2021 Half-Earth dataset: the largest and most diverse dataset of herbarium specimen images, to date, for automatic taxon recognition. We also present the results of the Herbarium 2021 Half-Earth challenge, a competition that was part of the Eighth Workshop on Fine-Grained Visual Categorization (FGVC8) and hosted by Kaggle to encourage the development of models to automatically identify taxa from herbarium sheet images.
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Chlamydia pneumoniae is a Gram-negative bacterium responsible for a number of human respiratory diseases and linked to some chronic inflammatory diseases. The major outer membrane protein (MOMP) of Chlamydia is a conserved immunologically dominant protein located in the outer membrane, which, together with its surface exposure and abundance, has led to MOMP being the main focus for vaccine and antimicrobial studies in recent decades. MOMP has a major role in the chlamydial outer membrane complex through the formation of intermolecular disulphide bonds, although the exact interactions formed are currently unknown. Here, it is proposed that due to the large number of cysteines available for disulphide bonding, interactions occur between cysteine-rich pockets as opposed to individual residues. Such pockets were identified using a MOMP homology model with a supporting low-resolution (~4 Å) crystal structure. The localisation of MOMP in the E. coli membrane was assessed using direct stochastic optical reconstruction microscopy (dSTORM), which showed a decrease in membrane clustering with cysteine-rich regions containing two mutations. These results indicate that disulphide bond formation was not disrupted by single mutants located in the cysteine-dense regions and was instead compensated by neighbouring cysteines within the pocket in support of this cysteine-rich pocket hypothesis.
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We have previously reported the synthesis of a poly(ethylene glycol)-haloperidol (PEG-haloperidol) conjugate that retained affinity for its target D2 receptor and was stable in simulated physiological conditions. We hypothesised that this polymer-drug conjugate would localise haloperidol's activity either centrally or peripherally, dependent on the location of administration, due to the polymer preventing penetration through the blood-brain barrier (BBB). Herein, we validate this hypothesis using in vitro and in vivo studies. We first demonstrate, via a [35S]GTPγS-binding assay, that drug activity is retained after conjugation to the polymer, supportive of retention of effective therapeutic ability. Specifically, the PEG-haloperidol conjugate (at 10 and 100 nM) was able to significantly inhibit dopamine-induced G-protein activation via D2 receptors, albeit with a loss of potency compared to the free haloperidol (~18-fold at 10 nM). This loss of potency was further probed and rationalised using molecular docking experiments, which indicated that conjugated haloperidol can still bind to the D2 receptors, albeit with a flipped orientation in the binding pocket within the receptor, which may explain the reduced activity. Finally, rat catalepsy studies confirmed the restricted permeation of the conjugate through the BBB in vivo. Rats treated intravenously with free haloperidol became cataleptic, whereas normal behaviour was observed in rats that received the PEG-haloperidol conjugate, suggesting that conjugation can effectively prevent unwanted central effects. Taken together these results demonstrate that conjugating small molecules to polymers is effective at prohibiting penetration of the drug through the BBB and is a valid targeting strategy for drugs to facilitate peripheral (or central) effects without inducing side effects in other compartments.
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Catalepsia , Haloperidol , Animais , Barreira Hematoencefálica , Simulação de Acoplamento Molecular , Polietilenoglicóis , RatosRESUMO
Several milk/whey derived peptides possess high in vitro angiotensin I-converting enzyme (ACE) inhibitory activity. However, in some cases, poor correlation between the in vitro ACE inhibitory activity and the in vivo antihypertensive activity has been observed. The aim of this study is to gain insight into the structure-activity relationship of peptide sequences present in whey/milk protein hydrolysates with high ACE inhibitory activity, which could lead to a better understanding and prediction of their in vivo antihypertensive activity. The potential interactions between peptides produced from whey proteins, previously reported as high ACE inhibitors such as IPP, LIVTQ, IIAE, LVYPFP, and human ACE were assessed using a molecular docking approach. The results show that peptides IIAE, LIVTQ, and LVYPFP formed strong H bonds with the amino acids Gln 259, His 331, and Thr 358 in the active site of the human ACE. Interestingly, the same residues were found to form strong hydrogen bonds with the ACE inhibitory drug Sampatrilat. Furthermore, peptides IIAE and LVYPFP interacted with the amino acid residues Gln 259 and His 331, respectively, also in common with other ACE-inhibitory drugs such as Captopril, Lisinopril and Elanapril. Additionally, IIAE interacted with the amino acid residue Asp 140 in common with Lisinopril, and LIVTQ interacted with Ala 332 in common with both Lisinopril and Elanapril. The peptides produced naturally from whey by enzymatic hydrolysis interacted with residues of the human ACE in common with potent ACE-inhibitory drugs which suggests that these natural peptides may be potent ACE inhibitors.
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Inibidores da Enzima Conversora de Angiotensina/metabolismo , Peptídeos/metabolismo , Peptidil Dipeptidase A/metabolismo , Proteínas do Soro do Leite/metabolismo , Sequência de Aminoácidos , Inibidores da Enzima Conversora de Angiotensina/química , Animais , Sítios de Ligação , Captopril/química , Captopril/metabolismo , Domínio Catalítico , Humanos , Ligação de Hidrogênio , Simulação de Acoplamento Molecular , Peptídeos/química , Peptidil Dipeptidase A/química , Coelhos , Alinhamento de Sequência , Relação Estrutura-Atividade , Proteínas do Soro do Leite/químicaRESUMO
Isorhapontigenin is a polyphenolic compound found in Chinese herbs and grapes. It is a methoxylated analogue of a stilbenoid, resveratrol, which is well-known for its various beneficial effects including anti-platelet activity. Isorhapontigenin possesses greater oral bioavailability than resveratrol and has also been identified to possess anti-cancer and anti-inflammatory properties. However, its effects on platelet function have not been reported previously. In this study, we report the effects of isorhapontigenin on the modulation of platelet function. Isorhapontigenin was found to selectively inhibit ADP-induced platelet aggregation with an IC50 of 1.85⯵M although it displayed marginal inhibition on platelet aggregation induced by other platelet agonists at 100⯵M. However, resveratrol exhibited weaker inhibition on ADP-induced platelet aggregation (IC50â¯>â¯100⯵M) but inhibited collagen induced platelet aggregation at 50⯵M and 100⯵M. Isorhapontigenin also inhibited integrin αIIbß3 mediated inside-out and outside-in signalling and dense granule secretion in ADP-induced platelet activation but interestingly, no effect was observed on α-granule secretion. Isorhapontigenin did not exert any cytotoxicity on platelets at the concentrations of up to 100⯵M. Furthermore, it did not affect haemostasis in mice at the IC50 concentration (1.85⯵M). In addition, the mechanistic studies demonstrated that isorhapontigenin increased cAMP levels and VASP phosphorylation at Ser157 and decreased Akt phosphorylation. This suggests that isorhapontigenin may interfere with cAMP and PI3K signalling pathways that are associated with the P2Y12 receptor. Molecular docking studies emphasised that isorhapontigenin has greater binding affinity to P2Y12 receptor than resveratrol. Our results demonstrate that isorhapontigenin has selective inhibitory effects on ADP-stimulated platelet activation possibly via P2Y12 receptor.
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Plaquetas/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Estilbenos/farmacologia , Difosfato de Adenosina/farmacologia , Animais , Plaquetas/metabolismo , Avaliação Pré-Clínica de Medicamentos , Feminino , Voluntários Saudáveis , Humanos , Concentração Inibidora 50 , Masculino , Camundongos , Modelos Animais , Simulação de Acoplamento Molecular , Inibidores da Agregação Plaquetária/uso terapêutico , Testes de Função Plaquetária , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/antagonistas & inibidores , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/metabolismo , Receptores Purinérgicos P2Y12/química , Receptores Purinérgicos P2Y12/metabolismo , Resveratrol/análogos & derivados , Resveratrol/farmacologia , Transdução de Sinais/efeitos dos fármacos , Estilbenos/química , Estilbenos/uso terapêutico , Trombose/tratamento farmacológicoRESUMO
PURPOSE: To describe the presence of licensed tobacco retailers (LTRs), cigarette advertisements, price-reducing promotions, and compliance with tobacco control policies in New York State from 2004 to 2015 and to discuss implications and lessons learned from 11 years of experience conducting LTR surveys. DESIGN: Annual surveys of tobacco advertising from cross-sectional, stratified random samples of LTRs in New York State from 2004 to 2015 were conducted by professional data collectors. Data for 2013 were unavailable as the survey was not fielded in that year. SETTING: New York State. PARTICIPANTS: Licensed tobacco retailers, which are stores licensed to sell tobacco in the state of New York. Between 3.6% (n = 800) and 19.7% (n = 3945) of all LTRs were sampled annually. MEASURES: The presence and number of cigarette advertisements and the presence of price-reducing promotions, required age-of-sale signage, and self-service tobacco displays were documented. ANALYSIS: We tested for significant differences between 2014 and 2015 and significant trends overall and by outlet type. We used logistic regression for binary outcomes and Poisson regression for count variables. RESULTS: The number of LTRs in New York State decreased 22.9% from 2004 (n = 25 740) to 2015 (n = 19 855). The prevalence and number of cigarette advertisements and the prevalence of cigarette price-reducing promotions decreased significantly over time. Compliance with posting required age-of-sale signs increased significantly from 2004 to 2015 and from 2014 to 2015. Compliance with the ban on self-service tobacco displays was consistently near 100%. CONCLUSION: The tobacco retail environment in New York State improved substantially from 2004 to 2015. The implications of these findings for youth and adult smoking and the associated social costs are unknown; however, decreases in pro-tobacco marketing, decreases in the number of LTRs, and improvements in compliance are likely to have positive impacts on youth and adult smoking outcomes, such as reduced initiation and increased cessation, given previous research findings.
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Publicidade/estatística & dados numéricos , Comércio/estatística & dados numéricos , Fidelidade a Diretrizes/estatística & dados numéricos , Produtos do Tabaco/economia , Produtos do Tabaco/estatística & dados numéricos , Estudos Transversais , Humanos , New York , Produtos do Tabaco/legislação & jurisprudênciaRESUMO
INTRODUCTION: Nicotine harms adolescent brain development and contributes to addiction. Some adolescents report using nicotine-free e-cigarettes, but the accuracy of their reporting is unclear. We explored adolescents' use of nicotine-free e-cigarettes and understanding of chemicals in e-cigarettes, including nicotine. METHODS: Using social media, we recruited 1589 US adolescents (aged 15-17) who reported past 30-day use of e-cigarettes in 2016. We assessed perceptions of the nicotine source in e-liquid and whether e-cigarette aerosol is just "water vapor." We explored differences among adolescents who usually used e-cigarettes with nicotine (nâ¯=â¯473) and without nicotine (nâ¯=â¯452). We used weights to calibrate our sample to the Youth Risk Behavior Survey. RESULTS: Twenty-nine percent usually used e-cigarettes without nicotine, 28% with nicotine, 39% with "both," and 5% were "not sure." Few participants (17% of non-nicotine users vs. 34% of nicotine users, pâ¯<â¯.001) understood the nicotine was derived from tobacco. Youth who thought e-cigarette aerosol was just water vapor were more likely to usually use without nicotine. Older adolescents and current tobacco users were less likely to usually use without nicotine. CONCLUSIONS: The adolescents who reported usually using e-cigarettes without nicotine had poorer knowledge of e-cigarettes. This lack of understanding could contribute to inaccurate reporting of nicotine use. Most youth thought the nicotine in e-cigarettes was artificial, potentially indicating a belief that this nicotine is "safer." The US Food & Drug Administration will require nicotine warnings on e-cigarettes in 2018; a complementary educational campaign could address youths' misperceptions about nicotine and other chemicals in e-cigarette aerosol.
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Compreensão , Nicotina/administração & dosagem , Psicologia do Adolescente , Vaping/efeitos adversos , Adolescente , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Masculino , Nicotina/efeitos adversos , Fatores de Risco , Estados Unidos , Vaping/psicologiaRESUMO
OBJECTIVE: Genetic studies in obese rodents and humans can provide novel insights into the mechanisms involved in energy homeostasis. METHODS: In this study, we genetically mapped the chromosomal region underlying the development of severe obesity in a mouse line identified as part of a dominant N-ethyl-N-nitrosourea (ENU) mutagenesis screen. We characterized the metabolic and behavioral phenotype of obese mutant mice and examined changes in hypothalamic gene expression. In humans, we examined genetic data from people with severe early onset obesity. RESULTS: We identified an obese mouse heterozygous for a missense mutation (pR108W) in orthopedia homeobox (Otp), a homeodomain containing transcription factor required for the development of neuroendocrine cell lineages in the hypothalamus, a region of the brain important in the regulation of energy homeostasis. OtpR108W/+ mice exhibit increased food intake, weight gain, and anxiety when in novel environments or singly housed, phenotypes that may be partially explained by reduced hypothalamic expression of oxytocin and arginine vasopressin. R108W affects the highly conserved homeodomain, impairs DNA binding, and alters transcriptional activity in cells. We sequenced OTP in 2548 people with severe early-onset obesity and found a rare heterozygous loss of function variant in the homeodomain (Q153R) in a patient who also had features of attention deficit disorder. CONCLUSIONS: OTP is involved in mammalian energy homeostasis and behavior and appears to be necessary for the development of hypothalamic neural circuits. Further studies will be needed to investigate the contribution of rare variants in OTP to human energy homeostasis.
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Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Sequência de Aminoácidos , Animais , Ansiedade/metabolismo , Sequência de Bases , Encéfalo/metabolismo , Mapeamento Cromossômico , Bases de Dados Genéticas , Feminino , Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento/genética , Genes Homeobox , Proteínas de Homeodomínio/fisiologia , Humanos , Hipotálamo/metabolismo , Masculino , Camundongos , Proteínas do Tecido Nervoso/fisiologia , Sistemas Neurossecretores/metabolismo , Obesidade/metabolismo , Fatores de Transcrição/genética , Transcriptoma/genéticaRESUMO
PURPOSE: Some adolescent users of e-cigarettes and other electronic vaping products (EVPs) report performing "vape tricks" (exhaling aerosol to make shapes). However, little is known about this behavior. We examined the frequency of performing and watching vape tricks and the characteristics of those most likely to perform vape tricks among a sample of adolescent EVP users. METHODS: We used social media ads to recruit a national convenience sample of U.S. adolescents (n = 1,729) to participate in an online survey in September 2016. Inclusion criteria required participants to be aged 15-17 years and to have used EVPs at least once in the past 30 days. RESULTS: The majority of EVP-using adolescents reported trying (77.8%) and watching vape tricks in person (83.7%) or online (74.0%). Risk factors for performing tricks included using advanced vaping devices, vaping every day, white race, moderate levels of seeing and sharing vaping information on social media, and believing that EVP use is more normative among peers. Likelihood of trying vape tricks decreased as beliefs about the harmfulness of EVPs increased. CONCLUSIONS: Vape tricks pose a potential threat to adolescent health if they encourage nonusers to initiate or current EVP users to use more frequently or switch to advanced devices that produce more harmful chemical emissions. Further research should examine the possible health effects of performing vape tricks, and future public health campaigns should be informed by an understanding of the appeal of this activity for adolescents.
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Comportamento do Adolescente , Sistemas Eletrônicos de Liberação de Nicotina/estatística & dados numéricos , Vaping/métodos , Adolescente , Feminino , Humanos , Internet , Masculino , Inquéritos e Questionários , Vaping/efeitos adversosRESUMO
Epidemiological studies suggest that fruits and vegetables may play a role in promoting bone growth and preventing age-related bone loss, attributable, at least in part, to phytochemicals such as flavonoids stimulating osteoblastogenesis. Through systematically screening the effect of flavonoids on the osteogenic differentiation of human mesenchymal stem cells in vitro and correlating activity with chemical structure using comparative molecular field analysis, we have successfully identified important structural features that relate to their activity, as well as reliably predicted the activity of compounds with unknown activity. Contour maps emphasized the importance of electronegativity, steric bulk, and a 2-C-3-C double bond at the flavonoid C-ring, as well as overall electropositivity and reduced steric bulk at the flavonoid B-ring. These results support a role for certain flavonoids in promoting osteogenic differentiation, thus their potential for preventing skeletal deterioration, as well as providing a foundation for the lead optimization of novel bone anabolics.
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Flavonoides/farmacologia , Osteogênese/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Flavonoides/química , Humanos , Células-Tronco Mesenquimais/efeitos dos fármacos , Estrutura Molecular , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
Flavonoids reduce cardiovascular disease risk through anti-inflammatory, anti-coagulant and anti-platelet actions. One key flavonoid inhibitory mechanism is blocking kinase activity that drives these processes. Flavonoids attenuate activities of kinases including phosphoinositide-3-kinase, Fyn, Lyn, Src, Syk, PKC, PIM1/2, ERK, JNK and PKA. X-ray crystallographic analyses of kinase-flavonoid complexes show that flavonoid ring systems and their hydroxyl substitutions are important structural features for their binding to kinases. A clearer understanding of structural interactions of flavonoids with kinases is necessary to allow construction of more potent and selective counterparts. We examined flavonoid (quercetin, apigenin and catechin) interactions with Src family kinases (Lyn, Fyn and Hck) applying the Sybyl docking algorithm and GRID. A homology model (Lyn) was used in our analyses to demonstrate that high-quality predicted kinase structures are suitable for flavonoid computational studies. Our docking results revealed potential hydrogen bond contacts between flavonoid hydroxyls and kinase catalytic site residues. Identification of plausible contacts indicated that quercetin formed the most energetically stable interactions, apigenin lacked hydroxyl groups necessary for important contacts and the non-planar structure of catechin could not support predicted hydrogen bonding patterns. GRID analysis using a hydroxyl functional group supported docking results. Based on these findings, we predicted that quercetin would inhibit activities of Src family kinases with greater potency than apigenin and catechin. We validated this prediction using in vitro kinase assays. We conclude that our study can be used as a basis to construct virtual flavonoid interaction libraries to guide drug discovery using these compounds as molecular templates.
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Flavonoides/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Quinases da Família src/antagonistas & inibidores , Trifosfato de Adenosina/metabolismo , Apigenina/química , Apigenina/farmacologia , Sítios de Ligação , Catequina/química , Catequina/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Flavonoides/química , Humanos , Simulação de Acoplamento Molecular , Domínios Proteicos , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas c-hck/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-hck/química , Proteínas Proto-Oncogênicas c-hck/metabolismo , Quercetina/química , Quercetina/farmacologia , Relação Estrutura-Atividade , Quinases da Família src/química , Quinases da Família src/metabolismoRESUMO
The formation of new blood vessels from the pre-existing vasculature (angiogenesis) is a crucial stage in cancer progression and, indeed, angiogenesis inhibitors are now used as anticancer agents, clinically. Here we have explored the potential of flavonoid derivatives as antiangiogenic agents. Specifically, we have synthesised methoxy and 4-thio derivatives of the natural flavones quercetin and luteolin, two of which (4-thio quercetin and 4-thio luteolin) had never been previously reported. Seven of these compounds showed significant (p < 0.05) antiangiogenic activity in an in vitro scratch assay. Their activity ranged from an 86% inhibition of the vascular endothelium growth factor (VEGF)-stimulated migration (observed for methoxyquercetin at 10 µM and for luteolin at 1 µM) to a 36% inhibition (for thiomethoxy quercetin at 10 µM). Western blotting studies showed that most (4 out of 7) compounds inhibited phosphorylation of the VEGF receptor-2 (VEGFR2), suggesting that the antiangiogenic activity was due to an interference with the VEGF/VEGFR2 pathway. Molecular modelling studies looking at the affinity of our compounds towards VEGFR and/or VEGF confirmed this hypothesis, and indeed the compound with the highest antiangiogenic activity (methoxyquercetin) showed the highest affinity towards VEGFR and VEGF. As reports from others have suggested that structurally similar compounds can elicit biological responses via a non-specific, promiscuous membrane perturbation, potential interactions of the active compounds with a model lipid bilayer were assessed via DSC. Luteolin and its derivatives did not perturb the model membrane even at concentrations 10 times higher than the biologically active concentration and only subtle interactions were observed for quercetin and its derivatives. Finally, cytotoxicity assessment of these flavonoid derivatives against MCF-7 breast cancer cells demonstrated also a direct anticancer activity albeit at generally higher concentrations than those required for an antiangiogenic effect (10 fold higher for the methoxy analogues). Taken together these results show promise for flavonoid derivatives as antiangiogenic agents.
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Inibidores da Angiogênese/química , Inibidores da Angiogênese/farmacologia , Neoplasias da Mama/tratamento farmacológico , Movimento Celular/efeitos dos fármacos , Luteolina/química , Neovascularização Patológica/prevenção & controle , Quercetina/química , Western Blotting , Neoplasias da Mama/irrigação sanguínea , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Feminino , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Humanos , Neovascularização Patológica/metabolismo , Fosforilação/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND AND OBJECTIVE: Currently, the US Food and Drug Administration does not regulate electronic cigarette (e-cigarette) marketing unless it is advertised as a smoking cessation aid. To date, the extent to which youth and young adults are exposed to e-cigarette television advertisements is unknown. The objective of this study was to analyze trends in youth and young adult exposure to e-cigarette television advertisements in the United States. METHODS: Nielsen data on television household audiences' exposure to e-cigarette advertising across US markets were examined by calendar quarter, year, and sponsor. RESULTS: Youth exposure to television e-cigarette advertisements, measured by target rating points, increased 256% from 2011 to 2013. Young adult exposure increased 321% over the same period. More than 76% of all youth e-cigarette advertising exposure occurred on cable networks and was driven primarily by an advertising campaign for 1 e-cigarette brand. CONCLUSIONS: E-cigarette companies currently advertise their products to a broad audience that includes 24 million youth. The dramatic increase in youth and young adult television exposure between 2011 and 2013 was driven primarily by a large advertising campaign on national cable networks. In the absence of evidence-based public health messaging, the current e-cigarette television advertising may be promoting beliefs and behaviors that pose harm to the public health. If current trends in e-cigarette television advertising continue, awareness and use of e-cigarettes are likely to increase among youth and young adults.
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Publicidade/estatística & dados numéricos , Fumar , Televisão , Adolescente , Criança , Humanos , Nebulizadores e Vaporizadores , Adulto JovemRESUMO
PURPOSE: Examine effects of exposure to two types of cessation advertisements on changes in cessation-related outcomes. DESIGN: Experimental data from a nationally representative, longitudinal sample of smokers, collected in three waves over 4 weeks. SETTING: National. Subjects. Three thousand and two adult U.S. smokers aged 18+ completed baseline and follow-up interviews at 2 and 4 weeks, from December 2010 to February 2011. INTERVENTION: Six randomly assigned conditions consisting of repeated exposure to cessation advertisements: why-to-quit advertisements featuring emotional, personal testimonies (1: WTQ-T) or graphic images (2: WTQ-G); how-to-quit advertisements (3: HTQ), a combination of both (4: WTQ-T + HTQ; 5: WTQ-G + HTQ), and no-ad condition (6: control). MEASURES: Cessation-related beliefs, attitudes, intentions, and quitting behavior. ANALYSIS: Multivariable ordinary least squares and logistic regressions testing whether exposure to antitobacco television advertisements were associated with changes in tobacco-related outcomes. RESULTS: Exposure to WTQ-T or WTQ-G advertisements, both alone and combined with HTQ advertisements, elicited positive change in beliefs, attitudes, and intentions as compared to controls. Smokers in three of four WTQ conditions were substantially more likely to have quit smoking at 4 weeks than controls (odds ratios range from 5.9 to 10.1, p < .05 or better). No effects were found for the HTQ-only condition. CONCLUSION: Exposure to WTQ advertisements markedly increases the odds that a smoker will quit in the study period, suggesting positive movement toward successful, long-term cessation. HTQ advertisements did not enhance advertising effectiveness and may not be suitable as a primary message strategy.
Assuntos
Publicidade , Conhecimentos, Atitudes e Prática em Saúde , Promoção da Saúde/métodos , Meios de Comunicação de Massa , Abandono do Hábito de Fumar , Adulto , Feminino , Humanos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Estados UnidosRESUMO
Methods for recombinant production of eukaryotic membrane proteins, yielding sufficient quantity and quality of protein for structural biology, remain a challenge. We describe here, expression and purification optimisation of the human SERCA2a cardiac isoform of Ca(2+) translocating ATPase, using Saccharomyces cerevisiae as the heterologous expression system of choice. Two different expression vectors were utilised, allowing expression of C-terminal fusion proteins with a biotinylation domain or a GFP- His8 tag. Solubilised membrane fractions containing the protein of interest were purified onto Streptavidin-Sepharose, Ni-NTA or Talon resin, depending on the fusion tag present. Biotinylated protein was detected using specific antibody directed against SERCA2 and, advantageously, GFP-His8 fusion protein was easily traced during the purification steps using in-gel fluorescence. Importantly, talon resin affinity purification proved more specific than Ni-NTA resin for the GFP-His8 tagged protein, providing better separation of oligomers present, during size exclusion chromatography. The optimised method for expression and purification of human cardiac SERCA2a reported herein, yields purified protein (> 90%) that displays a calcium-dependent thapsigargin-sensitive activity and is suitable for further biophysical, structural and physiological studies. This work provides support for the use of Saccharomyces cerevisiae as a suitable expression system for recombinant production of multi-domain eukaryotic membrane proteins.
Assuntos
Miocárdio/metabolismo , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/biossíntese , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética , Cromatografia de Afinidade/métodos , Ativação Enzimática , Humanos , Hidrólise , Proteínas Recombinantes de Fusão/isolamento & purificação , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/isolamento & purificaçãoRESUMO
Major outer membrane proteins (MOMPs) of Gram negative bacteria are one of the most intensively studied membrane proteins. MOMPs are essential for maintaining the structural integrity of bacterial outer membranes and in adaptation of parasites to their hosts. There is evidence to suggest a role for purified MOMP from Chlamydophila pneumoniae and corresponding MOMP-derived peptides in immune-modulation, leading to a reduced atherosclerotic phenotype in apoE(-/-) mice via a characteristic dampening of MHC class II activity. The work reported herein tests this hypothesis by employing a combination of homology modelling and docking to examine the detailed molecular interactions that may be responsible. A three-dimensional homology model of the C. pneumoniae MOMP was constructed based on the 14 transmembrane ß-barrel crystal structure of the fatty acid transporter from Escherichia coli, which provides a plausible transport mechanism for MOMP. Ligand docking experiments were used to provide details of the possible molecular interactions driving the binding of MOMP-derived peptides to MHC class II alleles known to be strongly associated with inflammation. The docking experiments were corroborated by predictions from conventional immuno-informatic algorithms. This work supports further the use of MOMP in C. pneumoniae as a possible vaccine target and the role of MOMP-derived peptides as vaccine candidates for immune-therapy in chronic inflammation that can result in cardiovascular events.
Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Chlamydophila pneumoniae/metabolismo , Alelos , Sequência de Aminoácidos , Animais , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/imunologia , Transporte Biológico , Infecções por Chlamydophila/imunologia , Infecções por Chlamydophila/metabolismo , Infecções por Chlamydophila/terapia , Chlamydophila pneumoniae/imunologia , Antígeno HLA-DR4/química , Antígeno HLA-DR4/genética , Antígeno HLA-DR4/imunologia , Antígenos de Histocompatibilidade Classe II/química , Antígenos de Histocompatibilidade Classe II/genética , Antígenos de Histocompatibilidade Classe II/imunologia , Imunoterapia , Camundongos , Modelos Moleculares , Simulação de Acoplamento Molecular , Dados de Sequência Molecular , Peptídeos/química , Peptídeos/imunologia , Peptídeos/metabolismo , Ligação Proteica , Conformação Proteica , Reprodutibilidade dos Testes , Alinhamento de SequênciaRESUMO
BACKGROUND: To illustrate the burden of high cigarette excise taxes on low-income smokers. METHODOLOGY/PRINCIPAL FINDINGS: Using data from the New York and national Adult Tobacco Surveys from 2010-2011, we estimated how smoking prevalence, daily cigarette consumption, and share of annual income spent on cigarettes vary by annual income (less than $30,000; $30,000-$59,999; and more than $60,000). The 2010-2011 sample includes 7,536 adults and 1,294 smokers from New York and 3,777 adults and 748 smokers nationally. Overall, smoking prevalence is lower in New York (16.1%) than nationally (22.2%) and is strongly associated with income in New York and nationally (P<.001). Smoking prevalence ranges from 12.2% to 33.7% nationally and from 10.1% to 24.3% from the highest to lowest income group. In 2010-2011, the lowest income group spent 23.6% of annual household income on cigarettes in New York (up from 11.6% in 2003-2004) and 14.2% nationally. Daily cigarette consumption is not related to income. CONCLUSIONS/SIGNIFICANCE: Although high cigarette taxes are an effective method for reducing cigarette smoking, they can impose a significant financial burden on low-income smokers.