RESUMO
We report novel polymyxin analogues with improved antibacterial in vitro potency against polymyxin resistant recent clinical isolates of Acinetobacter baumannii and Pseudomonas aeruginosa . In addition, a human renal cell in vitro assay (hRPTEC) was used to inform structure-toxicity relationships and further differentiate analogues. Replacement of the Dab-3 residue with a Dap-3 in combination with a relatively polar 6-oxo-1-phenyl-1,6-dihydropyridine-3-carbonyl side chain as a fatty acyl replacement yielded analogue 5x, which demonstrated an improved in vitro antimicrobial and renal cytotoxicity profiles relative to polymyxin B (PMB). However, in vivo PK/PD comparison of 5x and PMB in a murine neutropenic thigh model against P. aeruginosa strains with matched MICs showed that 5x was inferior to PMB in vivo, suggesting a lack of improved therapeutic index in spite of apparent in vitro advantages.
Assuntos
Infecção Hospitalar/tratamento farmacológico , Descoberta de Drogas , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Polimixinas/química , Polimixinas/farmacologia , beta-Alanina/análogos & derivados , Animais , Antibacterianos/química , Antibacterianos/farmacocinética , Antibacterianos/farmacologia , Antibacterianos/toxicidade , Cães , Feminino , Bactérias Gram-Negativas/fisiologia , Humanos , Masculino , Testes de Sensibilidade Microbiana , Polimixinas/farmacocinética , Polimixinas/toxicidade , Ratos , beta-Alanina/químicaRESUMO
Herein we describe the structure-aided design and synthesis of a series of pyridone-conjugated monobactam analogues with in vitro antibacterial activity against clinically relevant Gram-negative species including Pseudomonas aeruginosa , Klebsiella pneumoniae , and Escherichia coli . Rat pharmacokinetic studies with compound 17 demonstrate low clearance and low plasma protein binding. In addition, evidence is provided for a number of analogues suggesting that the siderophore receptors PiuA and PirA play a role in drug uptake in P. aeruginosa strain PAO1.
Assuntos
Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Monobactamas/farmacologia , Piridonas/farmacologia , Animais , Antibacterianos/química , Antibacterianos/farmacocinética , Escherichia coli/efeitos dos fármacos , Concentração Inibidora 50 , Klebsiella pneumoniae/efeitos dos fármacos , Masculino , Testes de Sensibilidade Microbiana , Estrutura Molecular , Monobactamas/química , Monobactamas/farmacocinética , Pseudomonas aeruginosa/efeitos dos fármacos , Piridonas/química , Piridonas/farmacocinética , Ratos , Ratos WistarRESUMO
Novel siderophore-linked monobactams with in vitro and in vivo anti-microbial activity against MDR Gram-negative pathogens are described.
Assuntos
Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Infecções por Bactérias Gram-Negativas/tratamento farmacológico , Monobactamas/farmacologia , Animais , Sítios de Ligação/efeitos dos fármacos , Proteínas Sanguíneas/química , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Infecções por Bactérias Gram-Negativas/microbiologia , Humanos , Camundongos , Testes de Sensibilidade Microbiana , Modelos Moleculares , Estrutura Molecular , Monobactamas/síntese química , Monobactamas/química , Ratos , Relação Estrutura-AtividadeRESUMO
We investigated the effects of the matrix metalloproteinase 13 (MMP13)-selective inhibitor, 5-(4-{4-[4-(4-fluorophenyl)-1,3-oxazol-2-yl]phenoxy}phenoxy)-5-(2-methoxyethyl) pyrimidine-2,4,6(1H,3H,5H)-trione (Cmpd-1), on the primary tumor growth and breast cancer-associated bone remodeling using xenograft and syngeneic mouse models. We used human breast cancer MDA-MB-231 cells inoculated into the mammary fat pad and left ventricle of BALB/c Nu/Nu mice, respectively, and spontaneously metastasizing 4T1.2-Luc mouse mammary cells inoculated into mammary fat pad of BALB/c mice. In a prevention setting, treatment with Cmpd-1 markedly delayed the growth of primary tumors in both models, and reduced the onset and severity of osteolytic lesions in the MDA-MB-231 intracardiac model. Intervention treatment with Cmpd-1 on established MDA-MB-231 primary tumors also significantly inhibited subsequent growth. In contrast, no effects of Cmpd-1 were observed on soft organ metastatic burden following intracardiac or mammary fat pad inoculations of MDA-MB-231 and 4T1.2-Luc cells respectively. MMP13 immunostaining of clinical primary breast tumors and experimental mice tumors revealed intra-tumoral and stromal expression in most tumors, and vasculature expression in all. MMP13 was also detected in osteoblasts in clinical samples of breast-to-bone metastases. The data suggest that MMP13-selective inhibitors, which lack musculoskeletal side effects, may have therapeutic potential both in primary breast cancer and cancer-induced bone osteolysis.
Assuntos
Neoplasias da Mama/complicações , Neoplasias da Mama/patologia , Inibidores de Metaloproteinases de Matriz , Osteólise/etiologia , Osteólise/patologia , Inibidores de Proteases/farmacologia , Animais , Neoplasias Ósseas/patologia , Neoplasias Ósseas/secundário , Neoplasias da Mama/enzimologia , Neoplasias da Mama/prevenção & controle , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Creatina Quinase/metabolismo , Modelos Animais de Doenças , Células Endoteliais/efeitos dos fármacos , Células Endoteliais/metabolismo , Feminino , Imunofluorescência , Humanos , Metaloproteinase 13 da Matriz/metabolismo , Camundongos , Osteoblastos/efeitos dos fármacos , Osteoblastos/enzimologia , Osteoblastos/patologia , Osteólise/enzimologia , Inibidores de Proteases/sangue , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
A novel series of monocarbam compounds exhibiting promising antibacterial activity against multidrug resistant Gram-negative microorganisms is reported, along with the synthesis of one such molecule MC-1 (1). Also reported are structure-activity relationships associated with the in vitro and in vivo efficacy of 1 and related analogues in addition to the hydrolytic stability of such compounds and possible implications thereof.
RESUMO
Respiratory tract bacterial strains are becoming increasingly resistant to currently marketed macrolide antibiotics. The current alternative telithromycin (1) from the newer ketolide class of macrolides addresses resistance but is hampered by serious safety concerns, hepatotoxicity in particular. We have discovered a novel series of azetidinyl ketolides that focus on mitigation of hepatotoxicity by minimizing hepatic turnover and time-dependent inactivation of CYP3A isoforms in the liver without compromising the potency and efficacy of 1.
Assuntos
Azetidinas/química , Resistência a Múltiplos Medicamentos/efeitos dos fármacos , Cetolídeos/química , Cetolídeos/farmacologia , Infecções Respiratórias/tratamento farmacológico , Animais , Bactérias/efeitos dos fármacos , Infecções Comunitárias Adquiridas/tratamento farmacológico , Suscetibilidade a Doenças , Descoberta de Drogas , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos , Humanos , Cetolídeos/efeitos adversos , Cetolídeos/síntese química , Cetolídeos/uso terapêutico , Camundongos , Testes de Sensibilidade MicrobianaRESUMO
Explorations in the pyrimidinetrione series of MMP-13 inhibitors led to the discovery of a series of spiro-fused compounds that are potent and selective inhibitors of MMP-13. While other spiro-fused motifs are hydrolytically unstable, presumably due to electronic destabilization of the pyrimidinetrione ring, the spiropyrrolidine series does not share this liability. Greater than 100-fold selectivity versus other MMP family members was achieved by incorporation of an extended aryl-heteroaryl P1'group. When dosed as the sodium salt, these compounds displayed excellent oral absorption and pharmacokinetic properties. Despite the selectivity, a representative of this series produced fibroplasia in a 14 day rat study.
Assuntos
Inibidores de Metaloproteinases de Matriz , Inibidores de Proteases/química , Pirimidinas/química , Pirrolidinas/química , Compostos de Espiro/química , Animais , Estabilidade Enzimática/efeitos dos fármacos , Metaloproteinase 13 da Matriz/metabolismo , Inibidores de Proteases/farmacologia , Pirimidinas/farmacologia , Pirrolidinas/farmacologia , Ratos , Compostos de Espiro/farmacologia , Relação Estrutura-AtividadeRESUMO
Using SAR from two related series of pyrimidinetrione-based inhibitors, compounds with potent MMP-13 inhibition and >100-fold selectivity against other MMPs have been identified. Despite high molecular weights, clogPs, and polar surface areas, the compounds are generally well absorbed and have excellent pharmacokinetic (PK) properties when dosed as sodium salts. In a rat fibrosis model, a compound from the series displayed no fibrosis at exposures many fold greater than its MMP-13 IC50.
Assuntos
Inibidores de Metaloproteinases de Matriz , Inibidores de Proteases/síntese química , Inibidores de Proteases/farmacologia , Pirimidinonas/química , Animais , Fibrose/tratamento farmacológico , Fibrose/patologia , Ácidos Hidroxâmicos/química , Concentração Inibidora 50 , Peso Molecular , Ratos , Sais/química , Sódio/química , Relação Estrutura-AtividadeRESUMO
A series of pipecolic hydroxamate inhibitors of MMP-13 and aggrecanase was discovered based on screening known inhibitors of TNF-alpha converting enzyme (TACE). Potency versus aggrecanase was optimized by modification of the benzyloxyarylsulfonamide group. Incorporation of geminal alkyl substitution at the 3-position of the piperidine ring improved metabolic stability, presumably by increasing steric hindrance around the metabolically labile hydroxamic acid. This modification also resulted in dramatic improvement of aggrecanase activity with a slight reduction in selectivity versus MMP-1. Synthesis, structure activity relationships, and strategies to reduce metabolic clearance are described.
Assuntos
Endopeptidases/efeitos dos fármacos , Ácidos Hidroxâmicos/farmacologia , Inibidores de Metaloproteinases de Matriz , Inibidores de Proteases/farmacologia , Ácidos Hidroxâmicos/química , Metaloproteinase 13 da Matriz , Inibidores de Proteases/químicaRESUMO
Through the use of computational modeling, a series of pyrimidinetrione-based inhibitors of MMP-13 was designed based on a lead inhibitor identified through file screening. Incorporation of a biaryl ether moiety at the C-5 position of the pyrimidinetrione ring resulted in a dramatic enhancement of MMP-13 potency. Protein crystallography revealed that this moiety binds in the S(1)(') pocket of the enzyme. Optimization of the C-4 substituent of the terminal aromatic ring led to incorporation of selectivity versus MMP-14 (MT-1 MMP). Structure activity relationships of the biaryl ether substituent are presented as is pharmacokinetic data for a compound that meets our in vitro potency and selectivity goals.
Assuntos
Inibidores Enzimáticos/síntese química , Inibidores de Metaloproteinases de Matriz , Pirimidinas/química , Sítios de Ligação , Colagenases/química , Cristalografia por Raios X , Inibidores Enzimáticos/farmacologia , Metaloproteinase 13 da Matriz , Relação Estrutura-AtividadeRESUMO
A series of novel MMP-13 and TNF-alpha converting enzyme inhibitors based on piperazine 2-hydroxamic acid scaffolds are described. The TACE, MMP-1 and MMP-13 activity of these inhibitors as well as the effect of substitution of the piperazine nitrogen and the P-1' benzyloxy tailpiece is discussed. Moderate in vivo activity is observed with several members of this group.