RESUMO
Acute lymphoblastic leukaemia (ALL) has a marked propensity to metastasize to the central nervous system (CNS). In contrast to brain metastases from solid tumours, metastases of ALL seldom involve the parenchyma but are isolated to the leptomeninges, which is an infrequent site for carcinomatous invasion. Although metastasis to the CNS occurs across all subtypes of ALL, a unifying mechanism for invasion has not yet been determined. Here we show that ALL cells in the circulation are unable to breach the blood-brain barrier in mice; instead, they migrate into the CNS along vessels that pass directly between vertebral or calvarial bone marrow and the subarachnoid space. The basement membrane of these bridging vessels is enriched in laminin, which is known to coordinate pathfinding of neuronal progenitor cells in the CNS. The laminin receptor α6 integrin is expressed in most cases of ALL. We found that α6 integrin-laminin interactions mediated the migration of ALL cells towards the cerebrospinal fluid in vitro. Mice with ALL xenografts were treated with either a PI3Kδ inhibitor, which decreased α6 integrin expression on ALL cells, or specific α6 integrin-neutralizing antibodies and showed significant reductions in ALL transit along bridging vessels, blast counts in the cerebrospinal fluid and CNS disease symptoms despite minimally decreased bone marrow disease burden. Our data suggest that α6 integrin expression, which is common in ALL, allows cells to use neural migratory pathways to invade the CNS.
Assuntos
Sistema Nervoso Central/patologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Animais , Anticorpos Neutralizantes/imunologia , Membrana Basal/metabolismo , Barreira Hematoencefálica/metabolismo , Medula Óssea , Movimento Celular , Sistema Nervoso Central/irrigação sanguínea , Sistema Nervoso Central/metabolismo , Líquido Cefalorraquidiano/metabolismo , Circulação Cerebrovascular , Classe I de Fosfatidilinositol 3-Quinases/antagonistas & inibidores , Progressão da Doença , Feminino , Xenoenxertos/imunologia , Xenoenxertos/patologia , Integrina alfa6/imunologia , Integrina alfa6/metabolismo , Laminina/metabolismo , Masculino , Camundongos , Camundongos SCID , Transplante de Neoplasias , Leucemia-Linfoma Linfoblástico de Células Precursoras/enzimologia , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Receptores de Laminina/antagonistas & inibidores , Receptores de Laminina/imunologia , Receptores de Laminina/metabolismo , Crânio , Espaço SubaracnóideoRESUMO
Elevated levels of mucins present in bronchiectatic airways predispose patients to bacterial infections and reduce the effectiveness of antibiotic therapies by directly inactivating antibiotics. Consequently, new antibiotics that are not inhibited by mucins are needed to treat chronic respiratory infections caused by Pseudomonas aeruginosa and Staphylococcus aureus. In these studies, we demonstrate that fosfomycin synergistically enhances the activity of tobramycin in the presence of mucin. The bactericidal killing of a novel 4:1 (wt/wt) combination of fosfomycin-tobramycin (FTI) is superior (>9 log(10) CFU/ml) relative to its individual components fosfomycin and tobramycin. Additionally, FTI has a mutation frequency resulting in an antibiotic resistance >3 log(10) lower than for fosfomycin and 4 log(10) lower than for tobramycin for P. aeruginosa. Mechanistic studies revealed that chemical adducts are not formed, suggesting that the beneficial effects of the combination are not due to molecular modification of the components. FTI displayed time-kill kinetics similar to tobramycin and killed in a concentration-dependent fashion. The bactericidal effect resulted from inhibition of protein biosynthesis rather than cell wall biosynthesis. Studies using radiolabeled antibiotics demonstrated that tobramycin uptake was energy dependent and that fosfomycin enhanced the uptake of tobramycin in P. aeruginosa in a dose-dependent manner. Lastly, mutants resistant to fosfomycin and tobramycin were auxotrophic for specific carbohydrates and amino acids, suggesting that the resistance arises from mutations in specific active transport mechanisms. Overall, these data demonstrate that fosfomycin enhances the uptake of tobramycin, resulting in increased inhibition of protein synthesis and ultimately bacterial killing.
Assuntos
Proteínas de Bactérias/genética , Proteínas de Transporte/genética , Fosfomicina/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Tobramicina/farmacologia , Proteínas de Bactérias/metabolismo , Transporte Biológico Ativo , Proteínas de Transporte/metabolismo , Sinergismo Farmacológico , Testes de Sensibilidade Microbiana , Mucinas/metabolismo , Mucinas/farmacologia , Taxa de Mutação , Biossíntese de Proteínas , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/crescimento & desenvolvimento , Tobramicina/metabolismoRESUMO
A series of PI3Kß selective inhibitors derived from a novel 4-(1H-benzo[d]imidazol-1-yl)quinoline chemotype has been rationally designed. Crucial to achieving the desired selectivity over the other class I PI3K isoforms, including the challenging δ-isoform, was the identification of a subset of substituted pyridine hinge binders. This work led to the discovery of (P)-14, a highly selective and orally bioavailable PI3Kß inhibitor displaying an excellent pharmacokinetic profile in addition to great cellular potency in various PTEN-deficient tumor cell lines. Results from a dog toxicology study revealing structure-related, off-target ocular toxicity are also briefly discussed.
RESUMO
Atropisomerism is a type of axial chirality in which enantiomers or diastereoisomers arise due to hindered rotation around a bond axis. In this manuscript, we report a case in which torsional scan studies guided the thoughtful creation of a restricted axis of rotation between two heteroaromatic systems of a phosphoinositide 3-kinase (PI3K) ß inhibitor, generating a pair of atropisomeric compounds with significantly different pharmacological and pharmacokinetic profiles. Emblematic of these differences, the metabolism of inactive ( M)-28 is primarily due to the cytosolic enzyme aldehyde oxidase, while active ( P)-28 has lower affinity for aldehyde oxidase, resulting in substantially better metabolic stability. Additionally, we report torsional scan and experimental studies used to determine the barriers of rotation of this novel PI3Kß inhibitor.
Assuntos
Desenho de Fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Inibidores de Fosfoinositídeo-3 Quinase , Trifosfato de Adenosina/metabolismo , Animais , Inibidores Enzimáticos/metabolismo , Concentração Inibidora 50 , Camundongos , Simulação de Acoplamento Molecular , Fosfatidilinositol 3-Quinases/química , Fosfatidilinositol 3-Quinases/metabolismo , Conformação Proteica , Quinazolinas/química , Quinazolinas/metabolismo , Quinazolinas/farmacologia , Estereoisomerismo , Especificidade por SubstratoRESUMO
Phosphoinositide 3-kinase (PI3K) ß signaling is required to sustain cancer cell growth in which the tumor suppressor phosphatase and tensin homolog (PTEN) has been deactivated. This manuscript describes the discovery, optimization, and in vivo evaluation of a novel series of PI3Kß/δ inhibitors in which PI3Kß potency was built in a PI3Kδ-selective template. This work led to the discovery of a highly selective PI3Kß/δ inhibitor displaying excellent pharmacokinetic profile and efficacy in a human PTEN-deficient LNCaP prostate carcinoma xenograft tumor model.
Assuntos
PTEN Fosfo-Hidrolase/genética , Inibidores de Fosfoinositídeo-3 Quinase , Neoplasias da Próstata/tratamento farmacológico , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/uso terapêutico , Animais , Linhagem Celular Tumoral , Classe Ia de Fosfatidilinositol 3-Quinase/metabolismo , Cães , Haplorrinos , Humanos , Masculino , Camundongos , Modelos Moleculares , Próstata/efeitos dos fármacos , Próstata/metabolismo , Próstata/patologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/metabolismo , Inibidores de Proteínas Quinases/farmacocinética , Inibidores de Proteínas Quinases/farmacologia , Ratos , Ratos Sprague-DawleyRESUMO
Aberrant signaling of phosphoinositide 3-kinase δ (PI3Kδ) has been implicated in numerous pathologies including hematological malignancies and rheumatoid arthritis. Described in this manuscript are the discovery, optimization, and in vivo evaluation of a novel series of pyridine-containing PI3Kδ inhibitors. This work led to the discovery of 35, a highly selective inhibitor of PI3Kδ which displays an excellent pharmacokinetic profile and is efficacious in a rodent model of rheumatoid arthritis.
RESUMO
Inhibition of phosphoinositide 3-kinase δ (PI3Kδ) is an appealing target for several hematological malignancies and inflammatory diseases. Herein, we describe the discovery and optimization of a series of propeller shaped PI3Kδ inhibitors comprising a novel triaminopyrimidine hinge binder. Combinations of electronic and structural strategies were employed to mitigate aldehyde oxidase mediated metabolism. This medicinal chemistry effort culminated in the identification of 52, a potent and highly selective inhibitor of PI3Kδ that demonstrates efficacy in a rat model of arthritis.
Assuntos
Artrite Experimental/tratamento farmacológico , Classe I de Fosfatidilinositol 3-Quinases/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Pirimidinas/química , Pirimidinas/farmacologia , Quinazolinonas/farmacologia , Animais , Artrite Experimental/induzido quimicamente , Artrite Experimental/enzimologia , Linfócitos B/citologia , Linfócitos B/efeitos dos fármacos , Linfócitos B/enzimologia , Células Cultivadas , Colágeno/toxicidade , Cristalografia por Raios X , Modelos Animais de Doenças , Feminino , Hepatócitos/efeitos dos fármacos , Hepatócitos/enzimologia , Humanos , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/enzimologia , Modelos Moleculares , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacocinética , Pirimidinas/farmacocinética , Quinazolinonas/química , Quinazolinonas/farmacocinética , Ratos , Ratos Endogâmicos Lew , Distribuição TecidualRESUMO
A fluoroquinolone prodrug, PA2808, was prepared and shown to convert to the highly active parent drug PA2789. In vitro and in vivo activation of PA2808 by alkaline phosphatase was demonstrated using disk diffusion and rat lung infection models. The water solubility of PA2808 showed a marked increase compared to PA2789 over a pH range suitable for aerosol drug delivery. A total of 48 analogues based on PA2789 were prepared and screened against a panel of Gram-positive and Gram-negative pathogens. Incorporating a cyclopropane-fused pyrrolidine (amine) at C-7 resulted in some of the most active analogues.
Assuntos
Ácidos Carboxílicos/química , Fluoroquinolonas/química , Fluoroquinolonas/farmacologia , Pró-Fármacos/química , Água/química , Animais , Antibacterianos/síntese química , Antibacterianos/química , Antibacterianos/farmacocinética , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Fluoroquinolonas/síntese química , Fluoroquinolonas/farmacocinética , Pulmão/metabolismo , Estrutura Molecular , Ácido Nalidíxico/análogos & derivados , Ácido Nalidíxico/síntese química , Ácido Nalidíxico/química , Ácido Nalidíxico/metabolismo , Ácido Nalidíxico/farmacocinética , Ácido Nalidíxico/farmacologia , Organofosfatos/síntese química , Organofosfatos/química , Organofosfatos/farmacocinética , Organofosfatos/farmacologia , Piperazinas/química , Piperazinas/metabolismo , Piperazinas/farmacocinética , Piperazinas/farmacologia , Pró-Fármacos/síntese química , Pró-Fármacos/metabolismo , Pró-Fármacos/farmacocinética , Ratos , Solubilidade , Relação Estrutura-AtividadeRESUMO
Using oral swab samples to detect West Nile virus in dead birds, we compared the Rapid Analyte Measurement Platform (RAMP) assay with VecTest and real-time reverse-transcriptase-polymerase chain reaction. The sensitivities of RAMP and VecTest for testing corvid species were 91.0% and 82.1%, respectively.
Assuntos
Doenças das Aves/diagnóstico , Aves/virologia , Kit de Reagentes para Diagnóstico , Febre do Nilo Ocidental/veterinária , Vírus do Nilo Ocidental/isolamento & purificação , Animais , Antígenos Virais/análise , Doenças das Aves/virologia , Encéfalo/virologia , Columbiformes/virologia , Galliformes/virologia , Boca/virologia , Passeriformes/virologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Sensibilidade e Especificidade , Manejo de Espécimes/métodos , Febre do Nilo Ocidental/diagnóstico , Febre do Nilo Ocidental/virologiaRESUMO
The VecTest antigen-capture assay for West Nile virus was performed on oral and tissue swabs from dead birds in New York State from April 2003 through July 2004. Results were compared with those from real-time reverse transcriptase-polymerase chain reaction of kidney or brain. Oral VecTest sensitivity is adequate for surveillance in American Crows (Corvus brachyrhynchos) (87%), Blue Jays (Cyanocitta cristata) (80%), and House Sparrows (Passer domesticus) (76%). Oral VecTest performed well for small samples of American Kestrels (Falco sparverius), Northern Cardinals (Cardinalis cardinalis), Common Grackles (Quiscalus quiscula), and House Finches (Carpodacus mexicanus). Poor sensitivity occurred in most raptors, Mourning Doves (Zenaida macroura), Fish Crows (Corvus ossifragus), and American Robins (Turdus migratorius). Specificity was excellent (98%), except for false-positive results that occurred mostly in Gray Catbirds (Dumatella carolinensis), Green Herons (Butorides virescens), and tests of blood and tissues. Feather pulp and kidney may be useful for VecTest assays in corvids.