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1.
Life Sci ; 285: 119996, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34597607

RESUMO

AIMS: Dezocine and pentazocine, widely prescribed in China for postoperative pain, were initially considered as mixed agonist/antagonist targeting µ-opioid receptors (MORs) and κ-opioid receptors (KORs). However, dezocine has been revealed to alleviate chronic neuropathic pain through MOR activation and norepinephrine reuptake inhibition (NRI). This study investigated dezocine- and pentazocine-induced antinociception and physical dependence development, compared to the typical MOR-NRI opioid tapentadol. MAIN METHODS: Calcium mobilization assay was conducted to assess the potency of the drugs while hot-plate test was performed to compare the antinociception. Physical dependence development was compared with morphine. KEY FINDINGS: Treatment with dezocine, pentazocine and tapentadol stimulated calcium mobilization in HEK293 cells stably expressed MORs but not KORs, whereas dezocine and pentazocine inhibited KOR activities. Subcutaneously injected dezocine-, tapentadol- and pentazocine-induced antinociception dose-dependently, in hot-plate test. Intrathecally injected MOR antagonist CTAP, norepinephrine depletor 6-OHDA and α2-adrenoceptor (α2-AR) antagonist yohimbine partially antagonized dezocine, pentazocine and tapentadol antinociception. Whereas specific KOR antagonist GNTI did not alter their antinociception, the putative inverse KOR agonist nor-BNI reduced dezocine and pentazocine antinociception. Moreover, combined CTAP and 6-OHDA or yohimbine blocked dezocine and tapentadol antinociception but displayed the same partial inhibition on pentazocine antinociception as CTAP alone. Furthermore, compared to morphine and pentazocine, long-term treatment with dezocine and tapentadol produced much less physical dependence-related withdrawal signs, which were restored by spinal 6-OHDA or yohimbine treatment. SIGNIFICANCE: Our findings illustrated that dezocine and tapentadol, but not pentazocine, exert remarkable antinociception in nociceptive pain with less abuse liability via dual mechanisms of MOR activation and NRI.


Assuntos
Analgésicos Opioides/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Dor Nociceptiva/tratamento farmacológico , Pentazocina/farmacologia , Receptores Opioides mu/agonistas , Tapentadol/farmacologia , Tetra-Hidronaftalenos/farmacologia , Inibidores da Captação Adrenérgica/química , Inibidores da Captação Adrenérgica/farmacologia , Analgésicos Opioides/química , Analgésicos Opioides/uso terapêutico , Animais , Compostos Bicíclicos Heterocíclicos com Pontes/química , Compostos Bicíclicos Heterocíclicos com Pontes/uso terapêutico , Agonismo de Drogas , Antagonismo de Drogas , Células HEK293 , Humanos , Camundongos , Pentazocina/química , Pentazocina/uso terapêutico , Receptores Adrenérgicos/metabolismo , Receptores Opioides kappa/agonistas , Receptores Opioides kappa/antagonistas & inibidores , Receptores Opioides mu/antagonistas & inibidores , Tapentadol/química , Tapentadol/uso terapêutico , Tetra-Hidronaftalenos/química , Tetra-Hidronaftalenos/uso terapêutico
2.
Hematology ; 26(1): 543-551, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34348586

RESUMO

Objectives: Chronic myeloid leukemia (CML) is a malignant tumor of the blood system. Gö6976, as a type of indolocarbazole and shows strong antitumor effects, but there have been no reports on the effect of Gö6976 on CML. The objectives of this research were: (1) to explore the impact of Gö6976 on CML in vitro and in vivo; and (2) to explore the drug toxicity of Gö6976 to normal cells and animals.Methods:K562 cells and CML mice were used to explore the effect of Gö6976 on CML. Peripheral blood mononuclear cells (PBMCs), CD34+ cells, and healthy mice were used to explore the drug toxicity of Gö6976.Results: Cell experiments showed that Gö6976 could inhibit the proliferation of K562 cells and enhance the inhibitory effects of imatinib at 5 µM and 10 µM, but it had little effect on CD34+ cells or PBMCs at concentrations less than 5 µM. Animal experiments showed that 2.5 mg/kg Gö6976 could effectively inhibit the development of CML in mice, and it had almost no effects on healthy mice at 2.5 mg/kg and 10 mg/kg.Discussion: Because of the direct inhibitory effect of Gö6976 on CML and its pharmacological enhancement effect on imatinib, it is foreseeable that Gö6976 could become a new type of anti-CML medicine. And the further research is needed.Conclusion: Our findings verified that Gö6976 could effectively inhibit CML in vitro and in vivo, and it is almost nontoxic to hematopoietic cells, immune cells, and healthy mice.


Assuntos
Carbazóis/farmacologia , Proliferação de Células/efeitos dos fármacos , Mesilato de Imatinib/farmacologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Animais , Carbazóis/agonistas , Agonismo de Drogas , Humanos , Mesilato de Imatinib/agonistas , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/metabolismo , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos NOD , Camundongos SCID , Ensaios Antitumorais Modelo de Xenoenxerto
3.
Biochem Pharmacol ; 180: 114150, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32682761

RESUMO

Metabolic diseases such as obesity, diabetes, and their comorbidities have converged as one of the most serious health concerns on a global scale. Selective glucagon-like peptide-1 (GLP-1) receptor (GLP-1R) agonists are one of the major therapeutics for type 2 diabetes and obesity. Polypharmacological approaches that enable modulation of multiple metabolic targets in a single drug have emerged as a potential avenue to improve therapeutic outcomes. Among numerous peptides under development are those targeting the GLP-1R and either the glucagon receptor (GCGR), glucose-dependent insulinotropic peptide receptor (GIPR) or all 3 receptors, as dual- or tri- peptide agonists. Despite many of them entering into clinical trials, current development has been based on only a limited understanding of the spectrum of potential pharmacological properties of these ligands beyond binding selectivity. In the present study, we examined the potential for agonists that target both GLP-1R and GCGR to exhibit biased agonism, comparing activity across proximal activation of Gs protein, cAMP accumulation, pERK1/2 and ß-arrestin recruitment. Three distinct dual agonists that have different relative cAMP production potency for GLP-1R versus GCGR, "peptide 15", MEDI0382 and SAR425899, and one triagonist of the GLP-1R, GCGR and GIPR were examined. We demonstrated that all novel peptides have distinct biased agonism profiles relative to either of the cognate agonists of the receptors, and to each other. This is an important feature of the pharmacology of this drug class that needs to be considered alongside selectivity, bioavailability and pharmacokinetics for rational optimization of new therapeutics.


Assuntos
Peptídeo 1 Semelhante ao Glucagon/agonistas , Oxintomodulina/farmacologia , Peptídeos/farmacologia , Receptores de Glucagon/agonistas , Sequência de Aminoácidos , Relação Dose-Resposta a Droga , Agonismo de Drogas , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Células HEK293 , Humanos , Oxintomodulina/genética , Oxintomodulina/metabolismo , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/metabolismo , Fragmentos de Peptídeos/farmacologia , Peptídeos/genética , Peptídeos/metabolismo , Ligação Proteica , Receptores de Glucagon/metabolismo
4.
Mol Pharmacol ; 97(1): 35-45, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31704718

RESUMO

Current operational models of agonism and allosterism quantify ligand actions at receptors where agonist concentration-response relationships are nonhyperbolic by introduction of a transducer slope that relates receptor occupancy to response. However, for some receptors nonhyperbolic concentration-response relationships arise from multiple endogenous agonist molecules binding to a receptor in a cooperative manner. Thus, we developed operational models of agonism in systems with cooperative agonist binding and evaluated the models by simulating data describing agonist effects. The models were validated by analyzing experimental data demonstrating the effects of agonists and allosteric modulators at receptors where agonist binding follows hyperbolic (M4 muscarinic acetylcholine receptors) or nonhyperbolic relationships (metabotropic glutamate receptor 5 and calcium-sensing receptor). For hyperbolic agonist concentration-response relationships, no differences in estimates of ligand affinity, efficacy, or cooperativity were observed when the slope was assigned to either a transducer slope or agonist binding slope. In contrast, for receptors with nonhyperbolic agonist concentration-response relationships, estimates of ligand affinity, efficacy, or cooperativity varied depending on the assignment of the slope. The extent of this variation depended on the magnitude of the slope value and agonist efficacy, and for allosteric modulators on the magnitude of cooperativity. The modified operational models described herein are well suited to analyzing agonist and modulator interactions at receptors that bind multiple orthosteric agonists in a cooperative manner. Accounting for cooperative agonist binding is essential to accurately quantify agonist and drug actions. SIGNIFICANCE STATEMENT: Some orthosteric agonists bind to multiple sites on a receptor, but current analytical methods to characterize such interactions are limited. Herein, we develop and validate operational models of agonism and allosterism for receptors with multiple orthosteric binding sites, and demonstrate that such models are essential to accurately quantify agonist and drug actions. These findings have important implications for the discovery and development of drugs targeting receptors such as the calcium-sensing receptor, which binds at least five calcium ions.


Assuntos
Sítios de Ligação/efeitos dos fármacos , Ionóforos de Cálcio/farmacologia , Agonismo de Drogas , Modelos Biológicos , Receptores de Detecção de Cálcio/agonistas , Regulação Alostérica/efeitos dos fármacos , Cálcio/metabolismo , Simulação por Computador , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Células HEK293 , Humanos , Ligantes , Receptor de Glutamato Metabotrópico 5/agonistas , Receptor de Glutamato Metabotrópico 5/química , Receptor de Glutamato Metabotrópico 5/metabolismo , Receptor Muscarínico M4/agonistas , Receptor Muscarínico M4/química , Receptor Muscarínico M4/metabolismo , Receptores de Detecção de Cálcio/química , Receptores de Detecção de Cálcio/metabolismo
5.
Mycoses ; 62(5): 428-433, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30784136

RESUMO

This study evaluated the in vitro susceptibility of Trichosporon asahii strains to diphenyl diselenide (DPDS) and ebselen (EBS) alone and in combination with amphotericin B (AMB), fluconazole (FCZ), itraconazole (ITZ) and caspofungin (CAS) using the microdilution method. EBS showed in vitro activity against T asahii strains with minimal inhibitory concentration (MIC) ranged from 0.25 to 8.0 µg/mL. For DPDS, the MIC ranged from 8.0 to 64 µg/mL. The combinations demonstrating the greatest synergism rate against fluconazole-resistant T asahii strains were the following: CAS + DPDS (96.67%), AMB + DPDS (93.33%), FCZ + DPDS (86.67%) and ITZ + DPDS (83.33%). The combinations AMB + DPDS and AMB + EBS exhibited the highest synergism rate against the fluconazole-susceptible (FS) T asahii strains (90%). Antagonism was observed in the following combinations: FCZ + EBS (80%) and FCZ + DPDS (13.33%) against the FS strains, and ITZ + EBS (20%) against the FR strains. Our findings suggest that the antimicrobial activity of DPDS and EBS against T. asahii and its use as an adjuvant therapy with antifungal agents warrant in vivo experimental investigation.


Assuntos
Antifúngicos/farmacologia , Azóis/farmacologia , Derivados de Benzeno/farmacologia , Agonismo de Drogas , Sinergismo Farmacológico , Compostos Organosselênicos/farmacologia , Trichosporon/efeitos dos fármacos , Isoindóis , Testes de Sensibilidade Microbiana
6.
Int J Neuropsychopharmacol ; 21(10): 962-977, 2018 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-30085126

RESUMO

Constitutive receptor activity/inverse agonism and functional selectivity/biased agonism are 2 concepts in contemporary pharmacology that have major implications for the use of drugs in medicine and research as well as for the processes of new drug development. Traditional receptor theory postulated that receptors in a population are quiescent unless activated by a ligand. Within this framework ligands could act as agonists with various degrees of intrinsic efficacy, or as antagonists with zero intrinsic efficacy. We now know that receptors can be active without an activating ligand and thus display "constitutive" activity. As a result, a new class of ligand was discovered that can reduce the constitutive activity of a receptor. These ligands produce the opposite effect of an agonist and are called inverse agonists. The second topic discussed is functional selectivity, also commonly referred to as biased agonism. Traditional receptor theory also posited that intrinsic efficacy is a single drug property independent of the system in which the drug acts. However, we now know that a drug, acting at a single receptor subtype, can have multiple intrinsic efficacies that differ depending on which of the multiple responses coupled to a receptor is measured. Thus, a drug can be simultaneously an agonist, an antagonist, and an inverse agonist acting at the same receptor. This means that drugs have an additional level of selectivity (signaling selectivity or "functional selectivity") beyond the traditional receptor selectivity. Both inverse agonism and functional selectivity need to be considered when drugs are used as medicines or as research tools.


Assuntos
Agonismo de Drogas , Agonismo Inverso de Drogas , Transdução de Sinais/efeitos dos fármacos , Animais , Humanos
7.
Mol Pharmacol ; 93(4): 259-265, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29326242

RESUMO

A single receptor can activate multiple signaling pathways that have distinct or even opposite effects on cell function. Biased agonists stabilize receptor conformations preferentially stimulating one of these pathways, and therefore allow a more targeted modulation of cell function and treatment of disease. Dedicated development of biased agonists has led to promising drug candidates in clinical development, such as the G protein-biased µ opioid receptor agonist oliceridine. However, leveraging the theoretical potential of biased agonism for drug discovery faces several challenges. Some of these challenges are technical, such as techniques for quantitative analysis of bias and development of suitable screening assays; others are more fundamental, such as the need to robustly identify in a very early phase which cell type harbors the cellular target of the drug candidate, which signaling pathway leads to the desired therapeutic effect, and how these pathways may be modulated in the disease to be treated. We conclude that biased agonism has potential mainly in the treatment of conditions with a well-understood pathophysiology; in contrast, it may increase effort and commercial risk under circumstances where the pathophysiology has been less well defined, as is the case with many highly innovative treatments.


Assuntos
Tomada de Decisões , Agonismo de Drogas , Descoberta de Drogas/métodos , Receptores Acoplados a Proteínas G/agonistas , Animais , Comportamento de Escolha , Descoberta de Drogas/tendências , Humanos , Receptores Acoplados a Proteínas G/metabolismo
8.
Sci Rep ; 7(1): 17935, 2017 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-29263342

RESUMO

Clinical efficacy regularly requires the combination of drugs. For an early estimation of the clinical value of (potentially many) combinations of pharmacologic compounds during discovery, the observed combination effect is typically compared to that expected under a null model. Mechanistic accuracy of that null model is not aspired to; to the contrary, combinations that deviate favorably from the model (and thereby disprove its accuracy) are prioritized. Arguably the most popular null model is the Loewe Additivity model, which conceptually maps any assay under study to a (virtual) single-step enzymatic reaction. It is easy-to-interpret and requires no other information than the concentration-response curves of the individual compounds. However, the original Loewe model cannot accommodate concentration-response curves with different maximal responses and, by consequence, combinations of an agonist with a partial or inverse agonist. We propose an extension, named Biochemically Intuitive Generalized Loewe (BIGL), that can address different maximal responses, while preserving the biochemical underpinning and interpretability of the original Loewe model. In addition, we formulate statistical tests for detecting synergy and antagonism, which allow for detecting statistically significant greater/lesser observed combined effects than expected from the null model. Finally, we demonstrate the novel method through application to several publicly available datasets.


Assuntos
Agonismo de Drogas , Antagonismo de Drogas , Quimioterapia Combinada , Modelos Teóricos , Relação Dose-Resposta a Droga , Humanos , Resultado do Tratamento
9.
J Pharmacol Exp Ther ; 363(3): 314-323, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28947487

RESUMO

An improved understanding of the endocannabinoid system has provided new avenues of drug discovery and development toward the management of pain and other behavioral maladies. Exogenous cannabinoid type 1 (CB1) receptor agonists such as Δ9-tetrahydrocannabinol are increasingly used for their medicinal actions; however, their utility is constrained by concern regarding abuse-related subjective effects. This has led to growing interest in the clinical benefit of indirectly enhancing the activity of the highly labile endocannabinoids N-arachidonoylethanolamine [AEA (or anandamide)] and/or 2-arachidonoylglycerol (2-AG) via catabolic enzyme inhibition. The present studies were conducted to determine whether such actions can lead to CB1 agonist-like subjective effects, as reflected in CB1-related discriminative stimulus effects in laboratory subjects. Squirrel monkeys (n = 8) that discriminated the CB1 full agonist AM4054 (0.01 mg/kg) from vehicle were used to study, first, the inhibitors of fatty acid amide hydrolase (FAAH) or monoacylglycerol lipase (MGL) alone or in combination [FAAH (URB597, AM4303); MGL (AM4301); FAAH/MGL (JZL195, AM4302)] and, second, the ability of the endocannabinoids AEA and 2-AG to produce CB1 agonist-like effects when administered alone or after enzyme inhibition. Results indicate that CB1-related discriminative stimulus effects were produced by combined, but not selective, inhibition of FAAH and MGL, and that these effects were nonsurmountably antagonized by low doses of rimonabant. Additionally, FAAH or MGL inhibition revealed CB1-like subjective effects produced by AEA but not by 2-AG. Taken together, the present data suggest that therapeutic effects of combined, but not selective, enhancement of AEA or 2-AG activity via enzyme inhibition may be accompanied by CB1 receptor-mediated subjective effects.


Assuntos
Amidoidrolases/antagonistas & inibidores , Aprendizagem por Discriminação/efeitos dos fármacos , Drogas em Investigação/farmacologia , Endocanabinoides/farmacologia , Inibidores Enzimáticos/farmacologia , Monoacilglicerol Lipases/antagonistas & inibidores , Receptor CB1 de Canabinoide/agonistas , Adamantano/administração & dosagem , Adamantano/efeitos adversos , Adamantano/análogos & derivados , Adamantano/farmacologia , Amidoidrolases/metabolismo , Animais , Ácidos Araquidônicos/administração & dosagem , Ácidos Araquidônicos/agonistas , Ácidos Araquidônicos/antagonistas & inibidores , Ácidos Araquidônicos/farmacologia , Comportamento Animal/efeitos dos fármacos , Antagonistas de Receptores de Canabinoides/administração & dosagem , Antagonistas de Receptores de Canabinoides/efeitos adversos , Antagonistas de Receptores de Canabinoides/farmacologia , Canabinol/administração & dosagem , Canabinol/efeitos adversos , Canabinol/análogos & derivados , Canabinol/farmacologia , Relação Dose-Resposta a Droga , Agonismo de Drogas , Antagonismo de Drogas , Drogas em Investigação/administração & dosagem , Drogas em Investigação/efeitos adversos , Endocanabinoides/administração & dosagem , Endocanabinoides/agonistas , Endocanabinoides/antagonistas & inibidores , Inibidores Enzimáticos/administração & dosagem , Inibidores Enzimáticos/efeitos adversos , Glicerídeos/administração & dosagem , Glicerídeos/agonistas , Glicerídeos/antagonistas & inibidores , Glicerídeos/farmacologia , Injeções Intramusculares , Injeções Intravenosas , Ligantes , Masculino , Monoacilglicerol Lipases/metabolismo , Proteínas do Tecido Nervoso/agonistas , Proteínas do Tecido Nervoso/antagonistas & inibidores , Proteínas do Tecido Nervoso/metabolismo , Alcamidas Poli-Insaturadas , Receptor CB1 de Canabinoide/antagonistas & inibidores , Receptor CB1 de Canabinoide/metabolismo , Saimiri
10.
Mol Pharmacol ; 92(4): 414-424, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28679508

RESUMO

An index of agonism is described that can be used to quantify agonist receptor selectivity, bias, cell-based agonism, and the effects of receptor mutation on signaling. The parameter is derived from agonist concentration-response curves and comprises the maximal response to the agonist (max) and the EC50 in the form of Δlog(max/EC50). This parameter is derived from equations describing agonists as positive allosteric facilitators of receptor-signaling protein interaction. A similar index is also derived to quantify the potentiating effects of positive allosteric modulators, which can be used to quantify in situ positive allosteric modulator activity in vivo. These indices lend themselves to statistical analysis and are system-independent in that the effects of the system processing of agonist response and differences in assay sensitivity and receptor expression are cancelled. The various applications of the Δlog(max/EC50) scale are described for each pharmacologic application.


Assuntos
Agonismo de Drogas , Mutação/fisiologia , Receptores Citoplasmáticos e Nucleares/agonistas , Receptores Citoplasmáticos e Nucleares/metabolismo , Transdução de Sinais/fisiologia , Regulação Alostérica/fisiologia , Animais , Relação Dose-Resposta a Droga , Humanos , Ligação Proteica/fisiologia , Relação Estrutura-Atividade
11.
Pharmacol Res ; 125(Pt A): 14-20, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28511989

RESUMO

Many of the effects of angiotensin II (AngII), including adrenocortical aldosterone release, are mediated by the AngII type 1 receptor (AT1R), a receptor with essential roles in cardiovascular homeostasis. AT1R belongs to the G protein-coupled receptor (GPCR) superfamily, mainly coupling to the Gq/11 type of G proteins. However, it also signals through ßarrestins, oftentimes in parallel to eliciting G protein-dependent signaling. This has spurred infinite possibilities for cardiovascular pharmacology, since various beneficial effects are purportedly exerted by AT1R via ßarrestins, unlike AT1R-induced G protein-mediated pathways that usually result in damaging cardiovascular effects, including hypertension and aldosterone elevation. Over the past decade however, a number of studies from our group and others have suggested that AT1R-induced ßarrestin signaling can also be damaging for the heart, similarly to the G protein-dependent one, with regard to aldosterone regulation. Additionally, AT1R-induced ßarrestin signaling in astrocytes from certain areas of the brain may also play a significant role in central regulation of blood pressure and hypertension pathogenesis. These findings have provided the impetus for testing available angiotensin receptor blockers (ARBs) in their efficacy towards blocking both routes (i.e. both G protein- and ßarrestin-dependent) of AT1R signaling in vitro and in vivo and also have promoted structure-activity relationship (SAR) studies for the AngII molecule in terms of ßarrestin signaling to certain cellular effects, e.g. adrenal aldosterone production. In the present review, we will recount all of these recent studies on adrenal and astrocyte AT1R-dependent ßarrestin signaling while underlining their implications for cardiovascular pathophysiology and therapy.


Assuntos
Aldosterona/metabolismo , Sistema Cardiovascular/metabolismo , Receptor Tipo 1 de Angiotensina/metabolismo , Antagonistas de Receptores de Angiotensina/farmacologia , Antagonistas de Receptores de Angiotensina/uso terapêutico , Animais , Sistema Cardiovascular/efeitos dos fármacos , Agonismo de Drogas , Antagonismo de Drogas , Humanos
12.
Artigo em Inglês | MEDLINE | ID: mdl-28392375

RESUMO

Increasing prevalence of antibiotic resistance has led research to focus on discovering new antimicrobial agents derived from the marine biome. Although ample studies have investigated sponges for their bioactive metabolites with promising prospects in drug discovery, the potentiating effects of sponge extracts on antibiotics still remains to be expounded. The present study aimed to investigate the antibacterial capacity of seven tropical sponges collected from Mauritian waters and their modulatory effect in association with three conventional antibiotics namely chloramphenicol, ampicillin and tetracycline. Disc diffusion assay was used to determine the inhibition zone diameter (IZD) of the sponge total crude extracts (CE), hexane (HF), ethyl acetate (EAF) and aqueous (AF) fractions against nine standard bacterial isolates whereas broth microdilution method was used to determine their minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs) and antibiotic potentiating activity of the most active sponge extract. MIC values of the sponge extracts ranged from 0.039 to 1.25mg/mL. Extracts from Neopetrosia exigua rich in beta-sitosterol and cholesterol displayed the widest activity spectrum against the 9 tested bacterial isolates whilst the best antibacterial profile was observed by its EAF particularly against Staphylococcus aureus and Bacillus cereus with MIC and MBC values of 0.039mg/mL and 0.078mg/mL, respectively. The greatest antibiotic potentiating effect was obtained with the EAF of N. exigua (MIC/2) and ampicillin combination against S. aureus. These findings suggest that the antibacterial properties of the tested marine sponge extracts may provide an alternative and complementary strategy to manage bacterial infections.


Assuntos
Antibacterianos/farmacologia , Organismos Aquáticos/química , Produtos Biológicos/farmacologia , Agonismo de Drogas , Descoberta de Drogas , Poríferos/química , Acetatos/química , Ampicilina/agonistas , Ampicilina/farmacologia , Animais , Antibacterianos/análise , Antibacterianos/química , Antibacterianos/isolamento & purificação , Organismos Aquáticos/crescimento & desenvolvimento , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Cloranfenicol/agonistas , Cloranfenicol/farmacologia , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Farmacorresistência Bacteriana/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Positivas/efeitos dos fármacos , Bactérias Gram-Positivas/crescimento & desenvolvimento , Oceano Índico , Maurício , Testes de Sensibilidade Microbiana , Poríferos/crescimento & desenvolvimento , Sitosteroides/análise , Sitosteroides/isolamento & purificação , Sitosteroides/farmacologia , Solventes/química , Tetraciclina/agonistas , Tetraciclina/farmacologia
13.
J Nutr Biochem ; 41: 124-136, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28092744

RESUMO

Quercetin, a bioflavonoid contained in several vegetables daily consumed, has been studied for long time for its antiinflammatory and anticancer properties. Quercetin interacts with multiple cancer-related pathways such as PI3K/AKT, Wnt/ß-catenin and STAT3. These pathways are hyperactivated in primary effusion lymphoma (PEL), an aggressive B cell lymphoma whose pathogenesis is strictly linked to the oncogenic virus Kaposis' Sarcoma-associated Herpesvirus (KSHV). In this study, we found that quercetin inhibited PI3K/AKT/mTOR and STAT3 pathways in PEL cells, and as a consequence, it down-regulated the expression of the prosurvival cellular proteins such as c-FLIP, cyclin D1 and cMyc. It also reduced the release of IL-6 and IL-10 cytokines, leading to PEL cell death. Moreover, quercetin induced a prosurvival autophagy in these cells and increased the cytotoxic effect of bortezomib, a proteasomal inhibitor, against them. Interestingly, quercetin decreased also the expression of latent and lytic KSHV proteins involved in PEL tumorigenesis and up-regulated the surface expression of HLA-DR and calreticulin, rendering the dying cells more likely detectable by the immune system. The results obtained in this study indicate that quercetin, which does not exert any cytotoxicity against normal B cells, may represent a good candidate for the treatment of this aggressive B cell lymphoma, especially in combination with autophagy inhibitors or with bortezomib.


Assuntos
Antineoplásicos Fitogênicos/metabolismo , Apoptose , Autofagia , Regulação para Baixo , Linfoma de Efusão Primária/metabolismo , Quercetina/metabolismo , Transdução de Sinais , Antineoplásicos/química , Antineoplásicos/farmacologia , Antineoplásicos Fitogênicos/efeitos adversos , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Linfócitos B/citologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Linfócitos B/metabolismo , Bortezomib/agonistas , Bortezomib/farmacologia , Linhagem Celular Tumoral , Células Cultivadas , Regulação para Baixo/efeitos dos fármacos , Agonismo de Drogas , Humanos , Interleucinas/antagonistas & inibidores , Interleucinas/metabolismo , Linfoma de Efusão Primária/tratamento farmacológico , Linfoma de Efusão Primária/imunologia , Linfoma de Efusão Primária/patologia , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/metabolismo , Fosfatidilinositol 3-Quinase/metabolismo , Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteassoma/química , Inibidores de Proteassoma/farmacologia , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Quercetina/efeitos adversos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Fator de Transcrição STAT3/antagonistas & inibidores , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/antagonistas & inibidores , Serina-Treonina Quinases TOR/metabolismo
14.
J Pharmacol Toxicol Methods ; 83: 94-106, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-27725245

RESUMO

We describe a method for estimating the affinities of ligands for active and inactive states of a G protein-coupled receptor (GPCR). Our protocol involves measuring agonist-induced signaling responses of a wild type GPCR and a constitutively active mutant of it under control conditions and after partial receptor inactivation or reduced receptor expression. Our subsequent analysis is based on the assumption that the activating mutation increases receptor isomerization into the active state without affecting the affinities of ligands for receptor states. A means of confirming this assumption is provided. Global nonlinear regression analysis yields estimates of 1) the active (Kact) and inactive (Kinact) receptor-state affinity constants, 2) the isomerization constant of the unoccupied receptor (Kq-obs), and 3) the sensitivity constant of the signaling pathway (KE-obs). The latter two parameters define the output response of the receptor, and hence, their ratio (Kq-obs/KE) is a useful measure of system bias. If the cellular system is reasonably stable and the Kq-obs and KE-obs values of the signaling pathway are known, the Kact and Kinact values of additional agonists can be estimated in subsequent experiments on cells expressing the wild type receptor. We validated our method through computer simulation, an analytical proof, and analysis of previously published data. Our approach provides 1) a more meaningful analysis of structure-activity relationships, 2) a means of validating in silico docking experiments on active and inactive receptor structures and 3) an absolute, in contrast to relative, measure of agonist bias.


Assuntos
Agonismo de Drogas , Modelos Biológicos , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/genética , Transdução de Sinais/fisiologia , Sítios de Ligação , Simulação por Computador , Relação Dose-Resposta a Droga , Humanos , Ligantes , Simulação de Acoplamento Molecular , Método de Monte Carlo , Mutação , Dinâmica não Linear , Ligação Proteica , Análise de Regressão , Transdução de Sinais/genética , Relação Estrutura-Atividade
15.
Antiviral Res ; 139: 161-170, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27889530

RESUMO

DESIGN: The HIV latent CD4+ T cell reservoir is broadly recognized as a barrier to HIV cure. Induction of HIV expression using protein kinase C (PKC) agonists is one approach under investigation for reactivation of latently infected CD4+ T cells (Beans et al., 2013; Abreu et al., 2014; Jiang et al., 2014; Jiang and Dandekar, 2015). We proposed that an increased understanding of the molecular mechanisms of action of PKC agonists was necessary to inform on biological signaling and pharmacodynamic biomarkers. RNA sequencing (RNA Seq) was applied to identify genes and pathways modulated by PKC agonists. METHODS: Human CD4+ T cells were treated ex vivo with Phorbol 12-myristate 13-acetate, prostatin or ingenol-3-angelate. At 3 h and 24 h post-treatment, cells were harvested and RNA-Seq was performed on RNA isolated from cell lysates. The genes differentially expressed across the PKC agonists were validated by quantitative RT-PCR (qPCR). A subset of genes was evaluated for their role in HIV reactivation using siRNA and CRISPR approaches in the Jurkat latency cell model. RESULTS: Treatment of primary human CD4+ T cells with PKC agonists resulted in alterations in gene expression. qPCR of RNA Seq data confirmed upregulation of 24 genes, including CD69, Egr1, Egr2, Egr3, CSF2, DUSP5, and NR4A1. Gene knockdown of Egr1 and Egr3 resulted in reduced expression and decreased HIV reactivation in response to PKC agonist treatment, indicating a potential role for Egr family members in latency reversal. CONCLUSION: Overall, our results offer new insights into the mechanism of action of PKC agonists, biomarkers of pathway engagement, and the potential role of EGR family in HIV reactivation.


Assuntos
HIV-1/fisiologia , Proteína Quinase C/metabolismo , Ativação Viral/efeitos dos fármacos , Latência Viral/efeitos dos fármacos , Biomarcadores , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/virologia , Células Cultivadas , Diterpenos/química , Diterpenos/farmacologia , Agonismo de Drogas , Proteína 1 de Resposta de Crescimento Precoce/genética , Proteína 3 de Resposta de Crescimento Precoce/genética , Expressão Gênica , Infecções por HIV/virologia , Humanos , Células Jurkat , Masculino , Forbóis/farmacologia , Análise de Sequência de RNA
16.
Nutr Cancer ; 68(6): 1010-20, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27367621

RESUMO

In this study, we examine the ability of arabinoxylan rice bran (MGN-3/Biobran) to enhance the apoptotic effect of paclitaxel (Taxol) at low concentration [2 mg/kg body weight (BW)] in animals bearing Ehrlich ascites carcinoma (EAC) cells and elucidate its mechanisms of action. On Day 8 following tumor cells inoculation, mice bearing tumors were administered MGN-3 alone (40 mg/kg BW), paclitaxel alone, or MGN-3 plus paclitaxel. On Day 30 post-tumor inoculation, we observed significant suppression of tumor volume (TV) with paclitaxel alone (59%), MGN-3 alone (77%), and MGN-3 plus paclitaxel (88%). Inhibition of tumor growth post-treatment with both agents, as compared with either treatment alone, was associated with a decrease in cell proliferation, a marked increase in the sub-G0/G1 population, an increase in DNA damage and apoptosis of tumor cells, and a significant maximization of the apoptosis index (AI)/proliferation index (PrI) ratio. Histopathological and electron microscopy examination of the combined treatment group showed an increase in the degenerative regions of the solid tumor tissue and abundant apoptotic cells. These data suggest that MGN-3 supplementation enhances tumor cell demise in the presence of a low dose of chemotherapeutic agent via apoptotic mechanism.


Assuntos
Antineoplásicos Fitogênicos/agonistas , Apoptose/efeitos dos fármacos , Carcinoma de Ehrlich/dietoterapia , Oryza/química , Paclitaxel/agonistas , Xilanos/uso terapêutico , Animais , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/farmacologia , Antineoplásicos Fitogênicos/uso terapêutico , Biomarcadores/metabolismo , Carcinoma de Ehrlich/tratamento farmacológico , Carcinoma de Ehrlich/patologia , Carcinoma de Ehrlich/ultraestrutura , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Terapia Combinada , Dano ao DNA , Suplementos Nutricionais , Agonismo de Drogas , Feminino , Camundongos , Microscopia Eletrônica de Transmissão , Paclitaxel/administração & dosagem , Paclitaxel/farmacologia , Paclitaxel/uso terapêutico , Fase de Repouso do Ciclo Celular/efeitos dos fármacos , Carga Tumoral/efeitos dos fármacos , Xilanos/metabolismo
17.
Drug Discov Today ; 21(11): 1735-1739, 2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27349169

RESUMO

The operational model of agonism offers a general equation to account for steep or flat functional curves by including a slope parameter different from 1. However, because this equation is not a Hill equation, those steep or flat experimental curves that follow the Hill model are excluded from the operational framework. This conceptual omission could have significant consequences in the estimation of affinity and efficacy - the operational model tends to overestimate agonist-receptor dissociation constants and operational efficacy parameters to accommodate the shape of theoretical curves to steep or flat experimental Hill curves. To avoid misled parameter estimates for an ample space of pharmacological data a new version of the operational model has been developed.


Assuntos
Agonismo de Drogas , Modelos Biológicos , Relação Dose-Resposta a Droga
18.
Biochem Pharmacol ; 107: 29-40, 2016 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-26920250

RESUMO

Poly (ADP-ribose) polymerases (PARPs) facilitate repairing of cancer cell DNA damage as a mean to promote cancer proliferation and metastasis. Inhibitors of PARPs which interfering DNA repair, in context of defects in other DNA repair mechanisms, can thus be potentially exploited to inhibit or even kill cancer cells. However, nondiscriminatory inhibition of PARPs, such as PARP2, may lead to undesired consequences. Here, we demonstrated the design and development of the Zj6413 as a potent and selective PARP1 catalytic inhibitor. It trapped PARP1/2 at damaged sites of DNA. As expected, the Zj6413 showed notable anti-tumor activity against breast cancer gene (BRCA) deficient triple negative breast cancers (TNBCs). Zj6413 treated breast cancers (BCs) showed an elevated level of DNA damage evidenced by the accumulation of γ-H2AX foci and DNA damaged related proteins. Zj6413 also induced G2/M arrest and cell death in the MX-1, MDA-MB-453 BC cells, exerted chemo-sensitizing effect on BRCA proficient cancer cells and potentiated Temozolomide (TMZ)'s cytotoxicity in MX-1 xenograft tumors mice. In conclusion, our study provided evidence that a new PARP inhibitor strongly inhibited the catalytic activity of PARPs, trapped them on nicked DNA and damaged the cancer cells, eventually inhibiting the growth of breast tumor cells in vitro and in vivo.


Assuntos
Desenho de Fármacos , Compostos de Organossilício/uso terapêutico , Inibidores de Poli(ADP-Ribose) Polimerases/uso terapêutico , Poli(ADP-Ribose) Polimerases/metabolismo , Quinazolinonas/uso terapêutico , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Animais , Antineoplásicos Alquilantes/efeitos adversos , Antineoplásicos Alquilantes/química , Antineoplásicos Alquilantes/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Apoptose/efeitos dos fármacos , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Dacarbazina/efeitos adversos , Dacarbazina/agonistas , Dacarbazina/análogos & derivados , Dacarbazina/uso terapêutico , Agonismo de Drogas , Feminino , Fase G2/efeitos dos fármacos , Humanos , Camundongos Nus , Compostos de Organossilício/efeitos adversos , Compostos de Organossilício/química , Compostos de Organossilício/farmacologia , Poli(ADP-Ribose) Polimerase-1 , Inibidores de Poli(ADP-Ribose) Polimerases/efeitos adversos , Inibidores de Poli(ADP-Ribose) Polimerases/química , Inibidores de Poli(ADP-Ribose) Polimerases/farmacologia , Poli(ADP-Ribose) Polimerases/química , Poli(ADP-Ribose) Polimerases/genética , Quinazolinonas/efeitos adversos , Quinazolinonas/química , Quinazolinonas/farmacologia , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Temozolomida , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
19.
Addiction ; 111(5): 767-74, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26503542

RESUMO

BACKGROUND AND AIMS: We examine the feasibility of agonist maintenance treatment for the major psychoactive drug classes: opioids, nicotine, benzodiazepines, cannabis, psychostimulants and alcohol. METHODS: Eight clinical criteria for an agonist maintenance drug were assessed for each major drug class. These related to pharmacological aspects of the drug (agonist, pharmacological stability, dose-response, non-toxic) and neurocognitive sequelae (psychiatric, cognitive, craving, salience). RESULTS: Opioids and nicotine met all eight criteria for a maintenance drug. While nicotine has not been promoted widely or used for maintenance, it has the potential to fulfil that role. Cannabis met five criteria and has potential, but long-term data on cognitive impairment are required. Benzodiazepine maintenance would appear an option for the high-dose chaotic abuser, also meeting five criteria, although clinic dosing appears the safest option. Psychostimulants (three of eight criteria) and alcohol (one of eight) appear poor propositions for maintenance, in terms of both their pharmacological and their neurocognitive characteristics. CONCLUSIONS: Drug classes have properties that distinguish them in their suitability for maintenance treatment. Some classes not yet used for maintenance (notably nicotine and cannabis) have potential to fulfil such a role. Others, however, by their inherent nature, appear unsuitable for such a treatment regimen.


Assuntos
Agonismo de Drogas , Transtornos Relacionados ao Uso de Substâncias/reabilitação , Dissuasores de Álcool/uso terapêutico , Analgésicos Opioides/uso terapêutico , Benzodiazepinas/uso terapêutico , Cannabis , Estimulantes do Sistema Nervoso Central/uso terapêutico , Etanol/uso terapêutico , Estudos de Viabilidade , Humanos , Nicotina/uso terapêutico
20.
PLoS One ; 10(4): e0126147, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25923669

RESUMO

Hypopharyngeal squamous cell carcinoma (HSCC) has the worst prognosis among head and neck cancers. Cisplatin (DDP)-based chemotherapy is an important part of multimodal treatments. However, resistance to DDP severely impairs the effectiveness of chemotherapy for HSCC. Chloroquine (CQ) has been reported to enhance the effectiveness of chemotherapy and radiotherapy in liver, pancreas, breast, prostate and colon tumors, but it is unclear whether CQ could increase the efficacy of DDP for treating HSCC. We inoculated BALB/c nude mice with a subcutaneous injection of human hypopharyngeal FaDu cells to generate our animal model. Mice were randomly divided into 4 groups and treated with vehicle control, CQ (60 mg/kg/day), DDP (5 mg/kg/6 days), or a combination of DDP and CQ. Tumor growth and survival of the mice were monitored. We found that CQ inhibited autophagy and increased DDP-induced apoptosis in the xenograft mouse model. CQ enhanced the efficacy of DDP, resulting in decreased tumor growth and prolonged survival of the mice. To test whether blocking autophagy enhanced the efficacy of DDP, FaDu cells were infected with lentiviral shRNA to Beclin-1 and inoculated into the flanks of nude mice. Inhibition of autophagy markedly enhanced the DDP-induced antitumor effect. Our study suggests that the addition of CQ to DDP-based chemotherapy could be a potential therapeutic strategy for treating HSCC, and the inhibition of autophagy may contribute to chemotherapy sensitization in HSCC.


Assuntos
Apoptose/efeitos dos fármacos , Cloroquina/farmacologia , Cisplatino/farmacologia , Neoplasias Hipofaríngeas/tratamento farmacológico , Animais , Apoptose/genética , Linhagem Celular Tumoral , Cloroquina/agonistas , Cisplatino/agonistas , Agonismo de Drogas , Feminino , Humanos , Neoplasias Hipofaríngeas/genética , Neoplasias Hipofaríngeas/metabolismo , Neoplasias Hipofaríngeas/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Ensaios Antitumorais Modelo de Xenoenxerto
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