Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 30
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
2.
Front Oncol ; 11: 673213, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34408976

RESUMO

The mechanistic target of rapamycin (mTOR) is a kinase whose activity is elevated in hematological malignancies. mTOR-complex-1 (mTORC1) phosphorylates numerous substrates to promote cell proliferation and survival. Eukaryotic initiation factor 4E (eIF4E)-binding proteins (4E-BPs) are mTORC1 substrates with an integral role in oncogenic protein translation. Current pharmacological approaches to inhibit mTORC1 activity and 4E-BP phosphorylation have drawbacks. Recently we described a series of bi-steric compounds that are potent and selective inhibitors of mTORC1, inhibiting 4E-BP phosphorylation at lower concentrations than mTOR kinase inhibitors (TOR-KIs). Here we report the activity of the mTORC1-selective bi-steric inhibitor, RMC-4627, in BCR-ABL-driven models of B-cell acute lymphoblastic leukemia (B-ALL). RMC-4627 exhibited potent and selective inhibition of 4E-BP1 phosphorylation in B-ALL cell lines without inhibiting mTOR-complex-2 (mTORC2) activity. RMC-4627 suppressed cell cycle progression, reduced survival, and enhanced dasatinib cytotoxicity. Compared to a TOR-KI compound, RMC-4627 was more potent, and its effects on cell viability were sustained after washout in vitro. Notably, a once-weekly, well tolerated dose reduced leukemic burden in a B-ALL xenograft model and enhanced the activity of dasatinib. These preclinical studies suggest that intermittent dosing of a bi-steric mTORC1-selective inhibitor has therapeutic potential as a component of leukemia regimens, and further study is warranted.

4.
Nat Chem Biol ; 17(10): 1065-1074, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34168367

RESUMO

The clinical benefits of pan-mTOR active-site inhibitors are limited by toxicity and relief of feedback inhibition of receptor expression. To address these limitations, we designed a series of compounds that selectively inhibit mTORC1 and not mTORC2. These 'bi-steric inhibitors' comprise a rapamycin-like core moiety covalently linked to an mTOR active-site inhibitor. Structural modification of these components modulated their affinities for their binding sites on mTOR and the selectivity of the bi-steric compound. mTORC1-selective compounds potently inhibited 4EBP1 phosphorylation and caused regressions of breast cancer xenografts. Inhibition of 4EBP1 phosphorylation was sufficient to block cancer cell growth and was necessary for maximal antitumor activity. At mTORC1-selective doses, these compounds do not alter glucose tolerance, nor do they relieve AKT-dependent feedback inhibition of HER3. Thus, in preclinical models, selective inhibitors of mTORC1 potently inhibit tumor growth while causing less toxicity and receptor reactivation as compared to pan-mTOR inhibitors.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Desenho de Fármacos , Alvo Mecanístico do Complexo 1 de Rapamicina/antagonistas & inibidores , Neoplasias da Mama/tratamento farmacológico , Linhagem Celular Tumoral , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina/genética , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Relação Estrutura-Atividade
5.
Front Immunol ; 11: 576310, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33133093

RESUMO

Shp1, encoded by the gene Ptpn6, is a protein tyrosine phosphatase that transduces inhibitory signals downstream of immunoreceptors in many immune cell types. Blocking Shp1 activity represents an exciting potential immunotherapeutic strategy for the treatment of cancer, as Shp1 inhibition would be predicted to unleash both innate and adaptive immunity against tumor cells. Antibodies blocking the interaction between CD47 on tumor cells and SIRPα on macrophages enhance macrophage phagocytosis, show efficacy in preclinical tumor models, and are being evaluated in the clinic. Here we found that Shp1 bound to phosphorylated peptide sequences derived from SIRPα and transduced the anti-phagocytic signal, as Shp1 loss in mouse bone marrow-derived macrophages increased phagocytosis of tumor cells in vitro. We also generated a novel mouse model to evaluate the impact of global, inducible Ptpn6 deletion on anti-tumor immunity. We found that inducible Shp1 loss drove an inflammatory disease in mice that was phenotypically similar to that seen when Ptpn6 is knocked out from birth. This indicates that acute perturbation of Shp1 in vivo could drive hyperactivation of immune cells, which could be therapeutically beneficial, though at the risk of potential toxicity. In this model, we found that Shp1 loss led to robust anti-tumor immunity against two immune-rich syngeneic tumor models that are moderately inflamed though not responsive to checkpoint inhibitors, MC38 and E0771. Shp1 loss did not promote anti-tumor activity in the non-inflamed B16F10 model. The observed activity in MC38 and E0771 tumors was likely due to effects of both innate and adaptive immune cells. Following Shp1 deletion, we observed increases in intratumoral myeloid cells in both models, which was more striking in E0771 tumors. E0771 tumors also contained an increased ratio of effector to regulatory T cells following Shp1 loss. This was not observed for MC38 tumors, though we did find increased levels of IFNγ, a cytokine produced by effector T cells, in these tumors. Overall, our preclinical data suggested that targeting Shp1 may be an attractive therapeutic strategy for boosting the immune response to cancer via a mechanism involving both innate and adaptive leukocytes.


Assuntos
Adenocarcinoma/enzimologia , Neoplasias da Mama/enzimologia , Neoplasias do Colo/enzimologia , Melanoma Experimental/enzimologia , Proteína Tirosina Fosfatase não Receptora Tipo 6/deficiência , Neoplasias Cutâneas/enzimologia , Macrófagos Associados a Tumor/enzimologia , Imunidade Adaptativa , Adenocarcinoma/imunologia , Adenocarcinoma/patologia , Adenocarcinoma/terapia , Animais , Antígenos de Diferenciação/metabolismo , Neoplasias da Mama/imunologia , Neoplasias da Mama/patologia , Neoplasias da Mama/terapia , Neoplasias do Colo/imunologia , Neoplasias do Colo/patologia , Neoplasias do Colo/terapia , Feminino , Humanos , Imunidade Inata , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/metabolismo , Melanoma Experimental/imunologia , Melanoma Experimental/patologia , Melanoma Experimental/terapia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fagocitose , Proteína Tirosina Fosfatase não Receptora Tipo 6/genética , Receptores Imunológicos/metabolismo , Transdução de Sinais , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/terapia , Células THP-1 , Carga Tumoral , Microambiente Tumoral , Macrófagos Associados a Tumor/imunologia
6.
Cancer Res ; 80(13): 2889-2902, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32350067

RESUMO

The protein tyrosine phosphatase SHP2 binds to phosphorylated signaling motifs on regulatory immunoreceptors including PD-1, but its functional role in tumor immunity is unclear. Using preclinical models, we show that RMC-4550, an allosteric inhibitor of SHP2, induces antitumor immunity, with effects equivalent to or greater than those resulting from checkpoint blockade. In the tumor microenvironment, inhibition of SHP2 modulated T-cell infiltrates similar to checkpoint blockade. In addition, RMC-4550 drove direct, selective depletion of protumorigenic M2 macrophages via attenuation of CSF1 receptor signaling and increased M1 macrophages via a mechanism independent of CD8+ T cells or IFNγ. These dramatic shifts in polarized macrophage populations in favor of antitumor immunity were not seen with checkpoint blockade. Consistent with a pleiotropic mechanism of action, RMC-4550 in combination with either checkpoint or CSF1R blockade caused additive antitumor activity with complete tumor regressions in some mice; tumors intrinsically sensitive to SHP2 inhibition or checkpoint blockade were particularly susceptible. Our preclinical findings demonstrate that SHP2 thus plays a multifaceted role in inducing immune suppression in the tumor microenvironment, through both targeted inhibition of RAS pathway-dependent tumor growth and liberation of antitumor immune responses. Furthermore, these data suggest that inhibition of SHP2 is a promising investigational therapeutic approach. SIGNIFICANCE: Inhibition of SHP2 causes direct and selective depletion of protumorigenic M2 macrophages and promotes antitumor immunity, highlighting an investigational therapeutic approach for some RAS pathway-driven cancers.


Assuntos
Neoplasias da Mama/imunologia , Imunossupressores/farmacologia , Macrófagos/imunologia , Proteína Tirosina Fosfatase não Receptora Tipo 11/antagonistas & inibidores , Microambiente Tumoral/imunologia , Regulação Alostérica , Animais , Apoptose , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Neoplasias da Mama/prevenção & controle , Proliferação de Células , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Transdução de Sinais , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
7.
Nat Cell Biol ; 20(9): 1064-1073, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30104724

RESUMO

Oncogenic alterations in the RAS/RAF/MEK/ERK pathway drive the growth of a wide spectrum of cancers. While BRAF and MEK inhibitors are efficacious against BRAFV600E-driven cancers, effective targeted therapies are lacking for most cancers driven by other pathway alterations, including non-V600E oncogenic BRAF, RAS GTPase-activating protein (GAP) NF1 (neurofibromin 1) loss and oncogenic KRAS. Here, we show that targeting the SHP2 phosphatase (encoded by PTPN11) with RMC-4550, a small-molecule allosteric inhibitor, is effective in human cancer models bearing RAS-GTP-dependent oncogenic BRAF (for example, class 3 BRAF mutants), NF1 loss or nucleotide-cycling oncogenic RAS (for example, KRASG12C). SHP2 inhibitor treatment decreases oncogenic RAS/RAF/MEK/ERK signalling and cancer growth by disrupting SOS1-mediated RAS-GTP loading. Our findings illuminate a critical function for SHP2 in promoting oncogenic RAS/MAPK pathway activation in cancers with RAS-GTP-dependent oncogenic BRAF, NF1 loss and nucleotide-cycling oncogenic KRAS. SHP2 inhibition is a promising molecular therapeutic strategy for patients with cancers bearing these oncogenic drivers.


Assuntos
Biomarcadores Tumorais/genética , Guanosina Trifosfato/metabolismo , Mutação , Neoplasias/enzimologia , Neoplasias/genética , Neurofibromina 1/genética , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Proteínas Proto-Oncogênicas B-raf/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Inibidores Enzimáticos/farmacologia , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Predisposição Genética para Doença , Células HEK293 , Humanos , Camundongos Endogâmicos BALB C , Camundongos Nus , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Fenótipo , Proteína Tirosina Fosfatase não Receptora Tipo 11/antagonistas & inibidores , Proteína Tirosina Fosfatase não Receptora Tipo 11/genética , Proteína SOS1/metabolismo , Transdução de Sinais , Carga Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto , Quinases raf/metabolismo
8.
Int J Neuropsychopharmacol ; 18(2)2014 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-25522383

RESUMO

BACKGROUND: Monoamine reuptake inhibitors exhibit unique clinical profiles that reflect distinct engagement of the central nervous system (CNS) transporters. METHODS: We used a translational strategy, including rodent pharmacokinetic/pharmacodynamic modeling and positron emission tomography (PET) imaging in humans, to establish the transporter profile of TD-9855, a novel norepinephrine and serotonin reuptake inhibitor. RESULTS: TD-9855 was a potent inhibitor of norepinephrine (NE) and serotonin 5-HT uptake in vitro with an inhibitory selectivity of 4- to 10-fold for NE at human and rat transporters. TD-9855 engaged norepinephrine transporters (NET) and serotonin transporters (SERT) in rat spinal cord, with a plasma EC50 of 11.7 ng/mL and 50.8 ng/mL, respectively, consistent with modest selectivity for NET in vivo. Accounting for species differences in protein binding, the projected human NET and SERT plasma EC50 values were 5.5 ng/mL and 23.9 ng/mL, respectively. A single-dose, open-label PET study (4-20mg TD-9855, oral) was conducted in eight healthy males using the radiotracers [(11)C]-3-amino-4- [2-[(di(methyl)amino)methyl]phenyl]sulfanylbenzonitrile for SERT and [(11)C]-(S,S)-methylreboxetine for NET. The long pharmacokinetic half-life (30-40 h) of TD-9855 allowed for sequential assessment of SERT and NET occupancy in the same subject. The plasma EC50 for NET was estimated to be 1.21 ng/mL, and at doses of greater than 4 mg the projected steady-state NET occupancy is high (>75%). After a single oral dose of 20mg, SERT occupancy was 25 (±8)% at a plasma level of 6.35 ng/mL. CONCLUSIONS: These data establish the CNS penetration and transporter profile of TD-9855 and inform the selection of potential doses for future clinical evaluation.


Assuntos
Inibidores da Captação de Neurotransmissores/farmacologia , Inibidores da Captação de Neurotransmissores/farmacocinética , Éteres Fenílicos/farmacologia , Éteres Fenílicos/farmacocinética , Piperidinas/farmacologia , Piperidinas/farmacocinética , Adulto , Compostos de Anilina , Animais , Análise Química do Sangue , Encéfalo/diagnóstico por imagem , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Meia-Vida , Humanos , Imageamento por Ressonância Magnética , Masculino , Modelos Biológicos , Morfolinas , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/metabolismo , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Ratos Sprague-Dawley , Reboxetina , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Medula Espinal/efeitos dos fármacos , Medula Espinal/metabolismo , Sulfetos
9.
PLoS One ; 8(9): e74891, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24098676

RESUMO

Multimodal analgesia is designed to optimize pain relief by coadministering drugs with distinct mechanisms of action or by combining multiple pharmacologies within a single molecule. In clinical settings, combinations of monoamine reuptake inhibitors and opioid receptor agonists have been explored and one currently available analgesic, tapentadol, functions as both a µ-opioid receptor agonist and a norepinephrine transporter inhibitor. However, it is unclear whether the combination of selective norepinephrine reuptake inhibition and µ-receptor agonism achieves an optimal antinociceptive synergy. In this study, we assessed the pharmacodynamic interactions between morphine and monoamine reuptake inhibitors that possess different affinities and selectivities for norepinephrine and serotonin transporters. Using the rat formalin model, in conjunction with measurements of ex vivo transporter occupancy, we show that neither the norepinephrine-selective inhibitor, esreboxetine, nor the serotonin-selective reuptake inhibitor, fluoxetine, produce antinociceptive synergy with morphine. Atomoxetine, a monoamine reuptake inhibitor that achieves higher levels of norepinephrine than serotonin transporter occupancy, exhibited robust antinociceptive synergy with morphine. Similarly, a fixed-dose combination of esreboxetine and fluoxetine which achieves comparable levels of transporter occupancy potentiated the antinociceptive response to morphine. By contrast, duloxetine, a monoamine reuptake inhibitor that achieves higher serotonin than norepinephrine transporter occupancy, failed to potentiate the antinociceptive response to morphine. However, when duloxetine was coadministered with the 5-HT3 receptor antagonist, ondansetron, potentiation of the antinociceptive response to morphine was revealed. These results support the notion that inhibition of both serotonin and norepinephrine transporters is required for monoamine reuptake inhibitor and opioid-mediated antinociceptive synergy; yet, excess serotonin, acting via 5-HT3 receptors, may reduce the potential for synergistic interactions. Thus, in the rat formalin model, the balance between norepinephrine and serotonin transporter inhibition influences the degree of antinociceptive synergy observed between monoamine reuptake inhibitors and morphine.


Assuntos
Analgesia/métodos , Morfina/metabolismo , Inibidores da Captação de Neurotransmissores/metabolismo , Dor Nociceptiva/tratamento farmacológico , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Animais , Cloridrato de Atomoxetina , Monoaminas Biogênicas/metabolismo , Cromatografia Líquida , Sinergismo Farmacológico , Cloridrato de Duloxetina , Fluoxetina , Formaldeído , Morfolinas , Inibidores da Captação de Neurotransmissores/farmacocinética , Ondansetron , Propilaminas , Ratos , Teste de Desempenho do Rota-Rod , Espectrometria de Massas em Tandem , Tiofenos
10.
J Am Chem Soc ; 135(41): 15526-35, 2013 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-24047255

RESUMO

Quorum sensing (QS) is a cell-to-cell communication system responsible for a variety of bacterial phenotypes including virulence and biofilm formation. QS is mediated by small molecules, autoinducers (AIs), including AI-2 that is secreted by both Gram-positive and -negative microbes. LsrR is a key transcriptional regulator that governs the varied downstream processes by perceiving AI-2 signal, but its activation via autoinducer-binding remains poorly understood. Here, we provide detailed regulatory mechanism of LsrR from the crystal structures in complexes with the native signal (phospho-AI-2, D5P) and two quorum quenching antagonists (ribose-5-phosphate, R5P; phospho-isobutyl-AI-2, D8P). Interestingly, the bound D5P and D8P molecules are not the diketone forms but rather hydrated, and the hydrated moiety forms important H-bonds with the carboxylate of D243. The D5P-binding flipped out F124 of the binding pocket, and resulted in the disruption of the dimeric interface-1 by unfolding the α7 segment. However, the same movement of F124 by the D8P'-binding did not cause the unfolding of the α7 segment. Although the LsrR-binding affinity of R5P (Kd, ∼1 mM) is much lower than that of D5P and D8P (∼2.0 and ∼0.5 µM), the α-anomeric R5P molecule fits into the binding pocket without any structural perturbation, and thus stabilizes the LsrR tetramer. The binding of D5P, not D8P and R5P, disrupted the tetrameric structure and thus is able to activate LsrR. The detailed structural and mechanistic insights from this study could be useful for facilitating design of new antivirulence and antibiofilm agents based on LsrR.


Assuntos
Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Homosserina/análogos & derivados , Lactonas/química , Lactonas/metabolismo , Percepção de Quorum , Proteínas Repressoras/química , Proteínas Repressoras/metabolismo , Sequência de Aminoácidos , Cristalização , Homosserina/química , Homosserina/metabolismo , Ligantes , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Molecular , Alinhamento de Sequência
11.
Bioorg Med Chem Lett ; 23(5): 1456-61, 2013 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-23347683

RESUMO

A series of 3-(phenoxy-phenyl-methyl)-pyrrolidine analogues were discovered to be potent and balanced norepinephrine (NE) and serotonin (5-hydroxytryptamine, 5-HT) reuptake inhibitors. Several of these compounds were identified to have suitable in vitro pharmacokinetic properties for an orally dosed and CNS-targeted drug. Compound 39b, in particular, was identified as a potent NET and SERT reuptake inhibitor (NSRI) with minimal off-target activity and demonstrated robust efficacy in the spinal nerve ligation model of pain behavior.


Assuntos
Inibidores da Captação de Neurotransmissores/farmacologia , Pirrolidinas/química , Pirrolidinas/farmacologia , Inibidores de Captação de Serotonina/farmacologia , Animais , Cristalografia por Raios X , Modelos Animais de Doenças , Humanos , Proteínas do Tecido Nervoso/efeitos dos fármacos , Proteínas do Tecido Nervoso/metabolismo , Norepinefrina/antagonistas & inibidores , Norepinefrina/química , Norepinefrina/metabolismo , Dor/tratamento farmacológico , Pirrolidinas/síntese química , Ratos , Relação Estrutura-Atividade
12.
Appl Microbiol Biotechnol ; 97(6): 2627-38, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23053069

RESUMO

Quorum sensing (QS), the process of autoinducer-mediated cell-cell signaling among bacteria, facilitates biofilm formation, virulence, and many other multicellular phenotypes. QS inhibitors are being investigated as antimicrobials because of their potential to reduce symptoms of infectious disease while slowing the emergence of resistant strains. Autoinducer-2 (AI-2) analogs have been shown to inhibit genotypic QS responses among many bacteria. We demonstrate for the first time, the ability of C1-alkyl AI-2 analog, isobutyl-DPD, to significantly inhibit the maturation of Escherichia coli biofilms grown in vitro. Using a novel microfluidic device that incorporates dynamic, real-time measurements of biofilm density, we also show that a combinatorial approach wherein isobutyl-DPD ((S)-4,5-dihydroxy-2,3-pentanedione) is used with the antibiotic gentamicin is quite effective in rendering near complete clearance of pre-existing E. coli biofilms. Similarly, another AI-2 analog, phenyl-DPD, also used in combination with near MIC levels of gentamicin, resulted in clearance of preformed Pseudomonas aeruginosa biofilms. Clearance of pre-existing biofilms has remained a significant health care challenge; these results warrant consideration of a new approach based on the combination of "quenching" QS signal transduction processes with traditional antibiotic treatment.


Assuntos
Antibacterianos/metabolismo , Biofilmes/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Escherichia coli/fisiologia , Homosserina/análogos & derivados , Lactonas/metabolismo , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/fisiologia , Biofilmes/crescimento & desenvolvimento , Escherichia coli/crescimento & desenvolvimento , Gentamicinas/metabolismo , Homosserina/metabolismo , Pseudomonas aeruginosa/crescimento & desenvolvimento
13.
Bioorg Med Chem Lett ; 22(19): 6048-52, 2012 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22959244

RESUMO

Utilization of Theravance's multivalent approach to drug discovery towards 5-HT(4) receptor agonists with a focus on identification of neutral (non-charged at physiological pH) secondary binding groups is described. Optimization of a quinolone-tropane primary binding group with a chiral 2-propanol linker to a range of neutral secondary binding group motifs, for binding affinity and functional potency at the 5-HT(4) receptor, selectivity over the 5-HT(3) receptor, oral pharmacokinetics, and in vivo efficacy in models of GI motility, afforded velusetrag (TD-5108). Velusetrag has achieved proof-of-concept in patients with chronic idiopathic constipation.


Assuntos
Compostos Azabicíclicos/farmacologia , Compostos Azabicíclicos/farmacocinética , Constipação Intestinal/tratamento farmacológico , Descoberta de Drogas , Receptores 5-HT4 de Serotonina/metabolismo , Agonistas do Receptor 5-HT4 de Serotonina/farmacologia , Agonistas do Receptor 5-HT4 de Serotonina/farmacocinética , Animais , Compostos Azabicíclicos/administração & dosagem , Compostos Azabicíclicos/uso terapêutico , Doença Crônica , Cobaias , Humanos , Estrutura Molecular , Ratos , Agonistas do Receptor 5-HT4 de Serotonina/química , Agonistas do Receptor 5-HT4 de Serotonina/uso terapêutico , Relação Estrutura-Atividade
14.
Bioorg Med Chem Lett ; 22(14): 4849-53, 2012 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-22683222

RESUMO

Further application of our multivalent approach to drug discovery directed to 5-HT(4) receptor agonists is described. Optimization of the linker and secondary binding amine in the indazole-tropane primary binding group series, for binding affinity and functional potency at the 5-HT(4) receptor, selectivity over the 5-HT(3) receptor, oral pharmacokinetics, and in vivo efficacy in models of GI motility, resulted in the identification of clinical compound TD-2749.


Assuntos
Compostos Heterocíclicos/química , Piperazinas/química , Agonistas do Receptor 5-HT4 de Serotonina/química , Administração Oral , Animais , Linhagem Celular , Descoberta de Drogas , Compostos Heterocíclicos/administração & dosagem , Compostos Heterocíclicos/farmacocinética , Humanos , Masculino , Estrutura Molecular , Especificidade de Órgãos , Piperazinas/administração & dosagem , Piperazinas/farmacocinética , Ratos , Ratos Sprague-Dawley , Agonistas do Receptor 5-HT4 de Serotonina/administração & dosagem , Agonistas do Receptor 5-HT4 de Serotonina/farmacocinética , Relação Estrutura-Atividade
15.
ACS Chem Biol ; 7(6): 1023-30, 2012 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-22433054

RESUMO

There have been intensive efforts to find small molecule antagonists for bacterial quorum sensing (QS) mediated by the "universal" QS autoinducer, AI-2. Previous work has shown that linear and branched acyl analogues of AI-2 can selectively modulate AI-2 signaling in bacteria. Additionally, LsrK-dependent phosphorylated analogues have been implicated as the active inhibitory form against AI-2 signaling. We used these observations to synthesize an expanded and diverse array of AI-2 analogues, which included aromatic as well as cyclic C-1-alkyl analogues. Species-specific analogues that disrupted AI-2 signaling in Escherichia coli and Salmonella typhimurium were identified. Similarly, analogues that disrupted QS behaviors in Pseudomonas aeruginosa were found. Moreover, we observed a strong correlation between LsrK-dependent phosphorylation of these acyl analogues and their ability to suppress QS. Significantly, we demonstrate that these analogues can selectively antagonize QS in single bacterial strains in a physiologically relevant polymicrobial culture.


Assuntos
Escherichia coli/metabolismo , Homosserina/análogos & derivados , Lactonas/química , Lactonas/metabolismo , Pseudomonas aeruginosa/metabolismo , Percepção de Quorum , Salmonella typhimurium/metabolismo , Escherichia coli/enzimologia , Proteínas de Escherichia coli/metabolismo , Homosserina/síntese química , Homosserina/química , Homosserina/metabolismo , Lactonas/síntese química , Fosfotransferases (Aceptor do Grupo Álcool)/metabolismo , Proteínas Repressoras/metabolismo , Salmonella typhimurium/enzimologia , Transdução de Sinais , beta-Galactosidase/metabolismo
16.
J Pharmacol Exp Ther ; 341(1): 137-45, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22235148

RESUMO

Translation of central nervous system occupancy and clinical effect from animal models to humans has remained elusive for many pharmacological targets. The current studies evaluate the ability of a rodent pharmacokinetic/pharmacodynamic (PK/PD) modeling approach to translate ex vivo occupancy determined in rats to that observed after positron emission tomography (PET) imaging in humans for the dual serotonin transporter (SERT) and norepinephrine transporter (NET) inhibitor duloxetine. Ex vivo transporter occupancy in rat spinal cord was evaluated after single oral doses of 0.3 to 60 mg/kg. A novel methodology, based on the initial rates of association of transporter selective radioligands to tissue homogenates, was developed and validated for the assessment of ex vivo transporter occupancy. Duloxetine exhibited selectivity for occupancy of SERT over NET in rat spinal cord with ED(50) values of 1 and 9 mg/kg, respectively. Corresponding EC(50) values for the inhibition of SERT and NET based on unbound duloxetine spinal cord concentrations were 0.5 and 8 nM. An effect compartment PK/PD modeling approach was used to analyze the relationship between the time course of duloxetine plasma concentration and SERT and NET occupancy. Duloxetine inhibited SERT and NET in rat spinal cord with a plasma EC(50) of 2.95 and 59.0 ng/ml, respectively. Similar plasma EC(50) values for the inhibition of SERT (2.29-3.7 ng/ml) have been reported from human PET studies. This study illustrates the value of translational PK/PD modeling approaches and suggests that the preclinical modeling approach used in the current study is capable of predicting plasma concentrations associated with 50% occupancy of SERT in the human central nervous system.


Assuntos
Modelos Neurológicos , Proteínas da Membrana Plasmática de Transporte de Norepinefrina/metabolismo , Proteínas da Membrana Plasmática de Transporte de Serotonina/metabolismo , Tiofenos/farmacocinética , Animais , Relação Dose-Resposta a Droga , Cloridrato de Duloxetina , Humanos , Masculino , Valor Preditivo dos Testes , Ligação Proteica/efeitos dos fármacos , Ligação Proteica/fisiologia , Ratos , Ratos Sprague-Dawley , Medula Espinal/efeitos dos fármacos , Medula Espinal/metabolismo , Tiofenos/metabolismo
17.
Neuropharmacology ; 61(1-2): 69-79, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21392515

RESUMO

There remains an urgent need for therapeutic agents that provide improved symptomatic treatment and attenuate disease progression in patients with Alzheimer's disease (AD). 5-HT(4) receptors are widely expressed in those CNS areas which receive substantial cholinergic input and are involved in cognition. The ability of 5-HT(4) receptor agonists to increase acetylcholine (ACh) release and reduce cognitive impairment in both animals and humans has been demonstrated. In addition, 5-HT(4) receptor agonist modulation of levels of the amyloid precursor protein (APP) derived peptides, soluble amyloid precursor protein (sAPPα) and amyloid beta protein (Aß) in the CNS has been reported. In this study, the preclinical properties of three structurally-distinct 5-HT(4) receptor selective agonists, PRX-03140, velusetrag and TD-8954, were studied to assess their potential for symptomatic and disease-modifying benefit in the treatment of AD. All three compounds exhibited high affinity for the rat 5-HT(4) receptor but could be discriminated on the basis of their agonist activity. In cAMP accumulation and sAPPα secretion assays using recombinant HEK293f-5-HT(4(d))-APP(695) cells, velusetrag and TD-8954 were potent, full agonists, relative to 5-HT, whereas PRX-03140 was a partial agonist (intrinsic activity 18%, relative to 5-HT). In a guinea pig colon isolated tissue preparation, TD-8954 exhibited lower intrinsic activity than velusetrag, and PRX-03140 had negligible agonist activity. In the rat Morris water maze (MWM) cognition test, velusetrag and TD-8954 (0.1 mg/kg), but not PRX-03140 (0.03-1 mg/kg), significantly reversed the scopolamine-induced spatial learning deficit via activation of 5-HT(4) receptors. Coadministration of subefficacious doses of the acetylcholinesterase inhibitor (AChEi), donepezil (0.1 mg/kg, i.p.), and either velusetrag or TD-8954 (0.01 mg/kg i.p.) resulted in reversal of the scopolamine-induced cognitive deficit. Pharmacokinetic data indicated that the CNS penetration for all three 5-HT(4) receptor agonists was relatively low. However, the pharmacodynamic-pharmacokinetic relationships in the MWM model for velusetrag and TD-8954 were consistent with their respective receptor pharmacology (binding affinity and intrinsic efficacy) and CNS penetration properties. Collectively, these findings support a potential role for potent and efficacious 5-HT(4) receptor agonists in the treatment of AD.


Assuntos
Precursor de Proteína beta-Amiloide/metabolismo , Cognição/fisiologia , Modificação Traducional de Proteínas/fisiologia , Receptores 5-HT4 de Serotonina/fisiologia , Agonistas do Receptor 5-HT4 de Serotonina/farmacologia , Animais , Cognição/efeitos dos fármacos , Relação Dose-Resposta a Droga , Cobaias , Células HEK293 , Humanos , Masculino , Ligação Proteica/fisiologia , Modificação Traducional de Proteínas/efeitos dos fármacos , Ratos , Ratos Sprague-Dawley , Agonistas do Receptor 5-HT4 de Serotonina/farmacocinética
18.
Mol Pharmacol ; 79(3): 389-99, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21139051

RESUMO

Biphenyl-2-yl-carbamic acid 1-{9-[(R)-2-hydroxy-2-(8-hydroxy-2-oxo-1,2-dihydro-quinolin-5-yl)-ethylamino]-nonyl}-piperidin-4-yl ester (THRX-198321) is a single molecule composed of a muscarinic acetylcholine receptor (mAChR) antagonist moiety, represented by the fragment MA, linked by a C9 polymethylene chain to a ß(2)-adrenoceptor (ß(2)AR) agonist moiety, represented by the fragment 8-hydroxy-5-((R)-1-hydroxy-2-methylamino-ethyl)-1H-quinolin-2-one (BA). THRX-198321 exhibited high affinity for mAChR (M(2) pK(I,App) = 10.57 ± 0.09; M(3) pK(I,App) = 10.07 ± 0.11) and ß(2)AR (pK(I,App) = 9.54 ± 0.15), with potent mAChR antagonist (M(2) pK(I,Fn) = 9.69 ± 0.23; M(3) pK(I,Fn) = 10.05 ± 0.17) and ß(2)AR agonist (pEC(50) = 9.25 ± 0.02) activities. Consistent with multivalent interactions, THRX-198321 binding affinity was >300-fold higher at mAChR and 29-fold higher at ß(2)AR relative to its monovalent fragments biphenyl carbamic acid piperidinyl ester (MA) and BA, respectively. THRX-198321 was a competitive antagonist at mAChR (M(2) pK(B) = 9.98 ± 0.13; M(3) pK(B) = 10.31 ± 0.89), whereas THRX-198321 agonist activity at ß(2)AR was competitively inhibited by propranolol. Interactions of THRX-198321 with an allosteric site on mAChR and a novel extracellular allosteric site on ß(2)AR, respectively, were detected by measuring THRX-198321-evoked changes in the dissociation rates for the orthosteric radioligands, [N-methyl-(3)H]scopolamine methyl chloride (M(2) pEC(50,diss) = 6.73 ± 0.10; M(3) pEC(50,diss) = 5.02 ± 0.14) and [4,6-propyl-(3)H]dihydroalprenolol (ß(2)AR pEC(50,diss) = 3.82 ± 0.25). The carbostyril-linker fragment (BA-L) binds to the allosteric site of mAChR (M(2) pEC(50,diss) = 5.06 ± 0.03; M(3) pEC(50,diss) = 4.15 ± 0.25), whereas the MA fragment binds to the allosteric site of ß(2)AR (pEC(50,diss) = 3.60 ± 0.18). Collectively, these observations suggest that THRX-198321 exhibits a multivalent bimodal orientation in the orthosteric and allosteric binding pockets of mAChR and ß(2)AR, a phenomenon that may be unique to this class of molecule.


Assuntos
Agonistas de Receptores Adrenérgicos beta 2/farmacologia , Carbamatos/farmacologia , Agonistas Muscarínicos/farmacologia , Quinolonas/farmacologia , Agonistas de Receptores Adrenérgicos beta 2/metabolismo , Animais , Sítios de Ligação , Ligação Competitiva , Células CHO , Carbamatos/metabolismo , Cricetinae , Cricetulus , AMP Cíclico/metabolismo , Guanosina 5'-O-(3-Tiotrifosfato)/metabolismo , Fosfatos de Inositol/metabolismo , Agonistas Muscarínicos/metabolismo , Farmacocinética , Quinolonas/metabolismo , Ensaio Radioligante
19.
J Am Chem Soc ; 132(32): 11141-50, 2010 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-20698680

RESUMO

The widespread use of antibiotics and the emergence of resistant strains call for new approaches to treat bacterial infection. Bacterial cell-cell communication or "quorum sensing" (QS) is mediated by "signatures" of small molecules that represent targets for "quenching" communication and avoiding virulent phenotypes. Only a handful of small molecules that antagonize the action of the "universal" autoinducer, AI-2, have been reported. The biological basis of antagonism, as well as the targets for these select few AI-2 antagonists, have not been clearly defined. We have developed C-1 alkyl analogs of AI-2 that quench the QS response in multiple bacterial species simultaneously. We also demonstrate the biological basis for this action. Like AI-2, the analogs are activated by the bacterial kinase, LsrK, and modulate AI-2 specific gene transcription through the transcriptional regulator, LsrR. Interestingly, addition of a single carbon to the C1-alkyl chain of the analog plays a crucial role in determining the effect of the analog on the QS response. While an ethyl modified analog is an agonist, propyl becomes an antagonist of the QS circuit. In a trispecies synthetic ecosystem comprised of E. coli, S. typhimurium, and V. harveyi we discovered both cross-species and species-specific anti-AI-2 QS activities. Our results suggest entirely new modalities for interrupting or tailoring the network of communication among bacteria.


Assuntos
Bactérias/citologia , Bactérias/efeitos dos fármacos , Homosserina/análogos & derivados , Lactonas/química , Lactonas/metabolismo , Pentanos/síntese química , Pentanos/farmacologia , Percepção de Quorum/efeitos dos fármacos , Bactérias/metabolismo , Transporte Biológico , Ecossistema , Homosserina/antagonistas & inibidores , Homosserina/química , Homosserina/metabolismo , Lactonas/antagonistas & inibidores , Modelos Moleculares , Conformação Molecular , Pentanos/química , Pentanos/metabolismo , Fosforilação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...