Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 9 de 9
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Future Med Chem ; 7(9): 1097-107, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26132521

RESUMO

BACKGROUND: Antiretroviral therapy (ART) has improved lifespan and quality of life of patients infected with the HIV-1. However, ART has several potential limitations, including the development of drug resistance and suboptimal penetration to selected anatomic compartments. Improving the delivery of antiretroviral molecules could overcome several of the limitations of current ART. RESULTS & CONCLUSION: Two to ten nanometer diameter inorganic gold crystals serve as a base scaffold to combine molecules with an array of properties in its surface. We show entry into different cell types, antiviral activity of an HIV integrase inhibitor conjugated in a gold nanoparticle and penetration into the brain in vivo without toxicity. Herein, gold nanoparticles prove to be a promising tool to use in HIV therapy.


Assuntos
Fármacos Anti-HIV/química , Portadores de Fármacos/química , Ouro/química , HIV-1/fisiologia , Nanopartículas Metálicas/química , Animais , Fármacos Anti-HIV/administração & dosagem , Fármacos Anti-HIV/síntese química , Encéfalo/metabolismo , Células Endoteliais/citologia , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Feminino , Proteína do Núcleo p24 do HIV/antagonistas & inibidores , Proteína do Núcleo p24 do HIV/metabolismo , Infecções por HIV/tratamento farmacológico , Humanos , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Nanopartículas Metálicas/toxicidade , Nanopartículas Metálicas/ultraestrutura , Camundongos , Camundongos Endogâmicos BALB C , Raltegravir Potássico/administração & dosagem , Raltegravir Potássico/síntese química , Raltegravir Potássico/química , Distribuição Tecidual , Replicação Viral/efeitos dos fármacos
2.
Mol Pharm ; 12(2): 542-53, 2015 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-25536192

RESUMO

A new transplantable ovarian tumor model is presented using a novel folate receptor (FR) positive, murine ovarian cancer cell line that emulates the human disease and induces widespread intraperitoneal (i.p.) tumors in immunocompetent mice within 4-8 weeks of implantation. Tumor development was monitored using a new positron emission tomography (PET) FR-targeting reporter with PET/computerized tomography (PET/CT) and fluorescence molecular tomography (FMT) using a commercial FR-targeting reporter. Conventional structural magnetic resonance imaging (MRI) was also performed. Adult female C57BL/6 mice were injected i.p. with 6 × 10(6) MKP-L FR+ cells. Imaging was performed weekly beginning 2 weeks after tumor induction. The albumin-binding, FR-targeting ligand cm09 was radiolabeled with the positron emitter (68)Ga and used to image the tumors with a small animal PET/CT. The FR-reporter FolateRSense 680 (PerkinElmer) was used for FMT and flow cytometry. Preclinical MRI (7 T) without FR-targeting was compared with the PET and FMT molecular imaging. Tumors were visible by all three imaging modalities. PET/CT had the highest imaging sensitivity at 3-3.5 h postadministration (mean %IA/g mean > 6) and visualized tumors earlier than the other two modalities with lower kidney uptake (mean %IA/g mean < 17) than previously reported FR-targeting agents in late stage disease. FMT showed relatively low FR-targeted agent in the bladder and kidneys, but yielded the lowest anatomical image resolution. MRI produced the highest resolution images, but it was difficult to distinguish tumors from abdominal organs during early progression since a FR-targeting MRI reporter was not used. Nevertheless, there was good correlation of imaging biomarkers between the three modalities. Tumors in the mouse ovarian cancer model could be detected using FR-targeted imaging as early as 2 weeks post i.p. injection of tumor cells. An imaging protocol should combine one or more of the modalities, e.g., PET/CT or PET/MRI for optimal tumor detection and delineation from surrounding tissues.


Assuntos
Receptores de Folato com Âncoras de GPI/metabolismo , Imagem Multimodal/métodos , Neoplasias Ovarianas/diagnóstico , Animais , Linhagem Celular Tumoral , Feminino , Imageamento por Ressonância Magnética , Camundongos , Neoplasias Ovarianas/diagnóstico por imagem , Tomografia por Emissão de Pósitrons , Tomografia Computadorizada por Raios X
3.
Chem Commun (Camb) ; 50(100): 15860-3, 2014 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-25350535

RESUMO

Antimicrobial drug discovery has slowed considerably over the last few decades. One major cause for concern is the lack of innovative approaches to treat infections caused by mycobacteria such as TB. Herein we demonstrate that our Small Molecule Variable Ligand Display (SMLVD) method for nanoparticle antibiotic discovery can be expanded around a ligand feed ratio parameter space to identify gold nanoparticle conjugates that are potent inhibitors of mycobacteria growth, with our most potent inhibitor able to reduce growth by five orders of magnitude at 8 µM.


Assuntos
Ouro/química , Nanopartículas Metálicas/química , Compostos de Sulfidrila/química , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Eritrócitos/citologia , Eritrócitos/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Humanos , Nanopartículas Metálicas/toxicidade , Testes de Sensibilidade Microbiana , Mycobacterium smegmatis/efeitos dos fármacos
4.
Bioorg Med Chem Lett ; 24(16): 3786-3790, 2014 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-25047578

RESUMO

The gelatinase members of the MMP family have consistently been associated with tumor invasiveness, which make them an attractive target for molecular imaging. We report new activatable proteolytic optical imaging agents that consist of triple-helical peptide (THP) conjugates, with high specificity to the gelatinases, bearing quenched cypate dyes. With quenching efficiencies up to 51%, the amplified fluorescence signal upon cypate3-THP hydrolysis by the gelatinases (kcat/KM values of 6.4×10(3) M(-1) s(-1) to 9.1×10(3) M(-1) s(-1) for MMP-2 and MMP-9, respectively) in mice bearing human fibrosarcoma xenografted tumors was monitored with fluorescence molecular tomography. There was significant fluorescence enhancement within the tumor and this enhancement was reduced by treatment with pan-MMP inhibitor, Ilomastat. These data, combined with the gelatinase substrate specificity observed in vitro, indicated the observed fluorescence at the site of the tumor was due to gelatinase mediated hydrolysis of cypate3-THP.


Assuntos
Corantes Fluorescentes , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Neoplasias Experimentais/diagnóstico , Imagem Óptica , Peptídeos , Animais , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/farmacologia , Fluorescência , Corantes Fluorescentes/química , Humanos , Ácidos Hidroxâmicos , Indóis/farmacologia , Camundongos , Estrutura Molecular , Neoplasias Experimentais/enzimologia , Neoplasias Experimentais/metabolismo , Peptídeos/química , Relação Estrutura-Atividade
5.
Molecules ; 19(6): 8571-88, 2014 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-24959683

RESUMO

Matrix metalloproteinases (MMP) 2 and 9, the gelatinases, have consistently been associated with tumor progression. The development of gelatinase-specific probes will be critical for identifying in vivo gelatinoic activity to understand the molecular role of the gelatinases in tumor development. Recently, a self-assembling homotrimeric triple-helical peptide (THP), incorporating a sequence from type V collagen, with high substrate specificity to the gelatinases has been developed. To determine whether this THP would be suitable for imaging protease activity, 5-carboxyfluorescein (5FAM) was conjugated, resulting in 5FAM3-THP and 5FAM6-THP, which were quenched up to 50%. 5FAM6-THP hydrolysis by MMP-2 and MMP-9 displayed kcat/KM values of 1.5 × 104 and 5.4 × 103 M-1 s-1, respectively. Additionally 5FAM6-THP visualized gelatinase activity in gelatinase positive HT-1080 cells, but not in gelatinase negative MCF-7 cells. Furthermore, the fluorescence in the HT-1080 cells was greatly attenuated by the addition of a MMP-2 and MMP-9 inhibitor, SB-3CT, indicating that the observed fluorescence release was mediated by gelatinase proteolysis and not non-specific proteolysis of the THPs. These results demonstrate that THPs fully substituted with fluorophores maintain their substrate specificity to the gelatinases in human cancer cells and may be useful in in vivo molecular imaging of gelatinase activity.


Assuntos
Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Peptídeos/farmacocinética , Tomografia Óptica/métodos , Linhagem Celular Tumoral , Colágeno Tipo V/química , Fluoresceínas/química , Fluorescência , Corantes Fluorescentes/química , Humanos , Células MCF-7 , Microscopia Confocal , Microscopia de Fluorescência , Peptídeos/síntese química , Peptídeos/química
6.
J Am Chem Soc ; 136(14): 5295-300, 2014 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-24624950

RESUMO

The emergence of resistance to multiple antimicrobial agents by pathogenic bacteria has become a significant global public health threat. Multi-drug-resistant (MDR) Gram-negative bacteria have become particularly problematic, as no new classes of small-molecule antibiotics for Gram-negative bacteria have emerged in over two decades. We have developed a combinatorial screening process for identifying mixed ligand monolayer/gold nanoparticle conjugates (2.4 nm diameter) with antibiotic activity. The method previously led to the discovery of several conjugates with potent activity against the Gram-negative bacterium Escherichia coli. Here we show that these conjugates are also active against MDR E. coli and MDR Klebsiella pneumoniae. Moreover, we have shown that resistance to these nanoparticles develops significantly more slowly than to a commercial small-molecule drug. These results, combined with their relatively low toxicity to mammalian cells and biocompatibility in vivo, suggest that gold nanoparticles may be viable new candidates for the treatment of MDR Gram-negative bacterial infections.


Assuntos
Antibacterianos/farmacologia , Materiais Biocompatíveis/farmacologia , Escherichia coli/efeitos dos fármacos , Ouro/farmacologia , Klebsiella pneumoniae/efeitos dos fármacos , Nanopartículas Metálicas/química , Antibacterianos/síntese química , Antibacterianos/química , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/química , Relação Dose-Resposta a Droga , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Ouro/química , Testes de Sensibilidade Microbiana , Relação Estrutura-Atividade
8.
Chem Commun (Camb) ; 46(40): 7516-8, 2010 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-20835461

RESUMO

Here we describe the use of simple 1-pot thiol exchange reactions to generate a library of mixed ligand-coated gold nanoparticles that was screened for antibiotic activity. A library of 120 nanoparticle conjugates was assembled and antibiotic activity toward E. coli was determined and found to depend upon the combination of thiols assembled onto the nanoparticles. The most active conjugate displayed 99.9% growth inhibition at 0.5 µM.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Ouro/química , Nanopartículas Metálicas/química , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Escherichia coli/crescimento & desenvolvimento , Infecções por Escherichia coli/tratamento farmacológico , Ligantes , Compostos de Sulfidrila/química
9.
Biochemistry ; 48(20): 4285-93, 2009 May 26.
Artigo em Inglês | MEDLINE | ID: mdl-19338266

RESUMO

G protein-coupled receptor (GPCR) kinases (GRKs) were discovered by virtue of their ability to phosphorylate activated GPCRs. They constitute a branch of the AGC kinase superfamily, but their mechanism of activation is largely unknown. To initiate a study of GRK2 activation, we sought to identify sites on GRK2 remote from the active site that are involved in interactions with their substrate receptors. Using the atomic structure of GRK2 in complex with Gbetagamma as a guide, we predicted that residues on the surface of the kinase domain that face the cell membrane would interact with the intracellular loops and carboxyl-terminal tail of the GPCR. Our study focused on two regions: the kinase large lobe and an extension of the kinase domain known as the C-tail. Residues in the GRK2 large lobe whose side chains are solvent exposed and facing the membrane were targeted for mutagenesis. Residues in the C-tail of GRK2, although not ordered in the crystal structure, were also targeted because this region has been implicated in receptor binding and in the regulation of AGC kinase activity. Four substitutions out of 20, all within or adjacent to the C-tail, resulted in significant deficiencies in the ability of the enzyme to phosphorylate two different GPCRS: rhodopsin, and the beta(2)-adrenergic receptor. The mutant exhibiting the most dramatic impairment, V477D, also showed significant defects in phosphorylation of nonreceptor substrates. Interestingly, Michaelis-Menten kinetics suggested that V477D had a 12-fold lower k(cat), but no changes in K(M), suggesting a defect in acquisition or stabilization of the closed state of the kinase domain. V477D was also resistant to activation by agonist-treated beta(2)AR. Therefore, Val477 and other residues in the C-tail are expected to play a role in the activation of GRK2 by GPCRs.


Assuntos
Quinase 2 de Receptor Acoplado a Proteína G/metabolismo , Quinase 2 de Receptor Acoplado a Proteína G/fisiologia , Animais , Células COS , Membrana Celular/metabolismo , Chlorocebus aethiops , Cristalografia por Raios X/métodos , Humanos , Cinética , Modelos Moleculares , Conformação Molecular , Peptídeos/química , Fosforilação , Estrutura Terciária de Proteína , Receptores Adrenérgicos beta 2/metabolismo , Rodopsina/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...