RESUMO
Compounds acting via the GPCR neurotensin receptor type 2 (NTS2) display analgesia in relevant preclinical models. The amide bond in nonpeptide NTS1 antagonists plays a central role in receptor recognition and molecular conformation. Using NTS2 FLIPR and binding assays, we found that it is also a key molecular structure for binding and calcium mobilization at NTS2. We found that reversed amides display a shift from agonist to antagonist activity and provided examples of the first competitive nonpeptide antagonists observed in the NTS2 FLIPR assay. These compounds will be valuable tools for determining the role of calcium signaling in vitro to NTS2 mediated analgesia.
Assuntos
Amidas/química , Sinalização do Cálcio/fisiologia , Receptores de Neurotensina/química , Amidas/farmacologia , Amidas/uso terapêutico , Bioensaio , Relação Dose-Resposta a Droga , Ligantes , Estrutura Molecular , Dor/tratamento farmacológico , Ligação Proteica/efeitos dos fármacos , Receptores de Neurotensina/antagonistas & inibidores , Receptores de Neurotensina/metabolismoRESUMO
Compounds acting via the GPCR neurotensin receptor type 2 (NTS2) display analgesic effects in relevant animal models. Using a pharmacophore model based on known NT receptor nonpeptide compounds, we screened commercial databases to identify compounds that might possess activity at NTS2 receptor sites. Modification of our screening hit to include structural features known to be recognized by NTS1 and NTS2, led to the identification of the novel NTS2 selective nonpeptide, N-{[6-chloro-4-(2,6-dimethoxyphenyl)quinazolin-2-yl]carbonyl}-l-leucine (9). This compound is a potent partial agonist in the FLIPR assay with a profile of activity similar to that of the reference NTS2 analgesic nonpeptide levocabastine (5).
Assuntos
Agonismo Parcial de Drogas , Leucina/análogos & derivados , Quinazolinas/farmacologia , Receptores de Neurotensina/agonistas , Cálcio/metabolismo , Humanos , Leucina/química , Leucina/farmacologia , Modelos Moleculares , Estrutura Molecular , Quinazolinas/química , Ensaio Radioligante , Relação Estrutura-AtividadeRESUMO
Compounds acting via the neurotensin receptor type 2 (NTS2) are known to be active in animal models of acute and chronic pain. To identify novel NTS2 selective analgesics, we searched for NTS2 selective nonpeptide compounds using a FLIPR assay and identified the title compound (NTRC-824, 5) that, to our knowledge, is the first nonpeptide that is selective for NTS2 versus NTS1 and behaves like the endogenous ligand neurotensin in the functional assay.
Assuntos
Analgésicos/farmacologia , Leucina/análogos & derivados , Dor/prevenção & controle , Receptores de Neurotensina/agonistas , Receptores de Neurotensina/antagonistas & inibidores , Sulfonamidas/farmacologia , Analgésicos/síntese química , Analgésicos/química , Animais , Ligação Competitiva , Células CHO , Cricetinae , Cricetulus , Relação Dose-Resposta a Droga , Humanos , Cinética , Leucina/síntese química , Leucina/química , Leucina/farmacologia , Modelos Químicos , Estrutura Molecular , Dor/fisiopatologia , Ratos , Receptores de Neurotensina/fisiologia , Sulfonamidas/síntese química , Sulfonamidas/químicaRESUMO
Compounds active at neurotensin receptors (NTS1 and NTS2) exert analgesic effects on different types of nociceptive modalities, including thermal, mechanical, and chemical stimuli. The NTS2 preferring peptide JMV-431 (2) and the NTS2 selective nonpeptide compound levocabastine (6) have been shown to be effective in relieving the pain associated with peripheral neuropathies. With the aim of identifying novel nonpeptide compounds selective for NTS2, we examined analogues of SR48692 (5a) using a FLIPR calcium assay in CHO cells stably expressing rat NTS2. This led to the discovery of the NTS2 selective nonpeptide compound 1-({[1-(4-fluorophenyl)-5-(2-methoxyphenyl)-1H-pyrazol-3-yl]carbonyl}amino)cyclohexane carboxylic acid (NTRC-739, 7b) starting from the nonselective compound 5a.
Assuntos
Analgésicos/química , Ácidos Cicloexanocarboxílicos/química , Pirazóis/química , Receptores de Neurotensina/agonistas , Analgésicos/síntese química , Analgésicos/farmacologia , Animais , Células CHO , Cálcio/metabolismo , Cricetulus , Ácidos Cicloexanocarboxílicos/síntese química , Ácidos Cicloexanocarboxílicos/farmacologia , Agonismo Parcial de Drogas , Pirazóis/síntese química , Pirazóis/farmacologia , Ensaio Radioligante , Ratos , Receptores de Neurotensina/antagonistas & inibidores , Relação Estrutura-AtividadeRESUMO
New dialkylimidazole based sterol 14α-demethylase inhibitors were prepared and tested as potential anti-Trypanosoma cruzi agents. Previous studies had identified compound 2 as the most potent and selective inhibitor against parasite cultures. In addition, animal studies had demonstrated that compound 2 is highly efficacious in the acute model of the disease. However, compound 2 has a high molecular weight and high hydrophobicity, issues addressed here. Systematic modifications were carried out at four positions on the scaffold and several inhibitors were identified which are highly potent (EC50 <1 nM) against T. cruzi in culture. The halogenated derivatives 36j, 36k, and 36p, display excellent activity against T. cruzi amastigotes, with reduced molecular weight and lipophilicity, and exhibit suitable physicochemical properties for an oral drug candidate.
Assuntos
Inibidores de 14-alfa Desmetilase/uso terapêutico , Doença de Chagas/tratamento farmacológico , Imidazóis/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/enzimologia , Inibidores de 14-alfa Desmetilase/administração & dosagem , Inibidores de 14-alfa Desmetilase/farmacologia , Animais , Doença de Chagas/parasitologia , Modelos MolecularesRESUMO
We report structure-activity studies of a large number of dialkyl imidazoles as inhibitors of Trypanosoma cruzi lanosterol-14alpha-demethylase (L14DM). The compounds have a simple structure compared to posaconazole, another L14DM inhibitor that is an anti-Chagas drug candidate. Several compounds display potency for killing T. cruzi amastigotes in vitro with values of EC(50) in the 0.4-10 nM range. Two compounds were selected for efficacy studies in a mouse model of acute Chagas disease. At oral doses of 20-50 mg/kg given after establishment of parasite infection, the compounds reduced parasitemia in the blood to undetectable levels, and analysis of remaining parasites by PCR revealed a lack of parasites in the majority of animals. These dialkyl imidazoles are substantially less expensive to produce than posaconazole and are appropriate for further development toward an anti-Chagas disease clinical candidate.
Assuntos
Doença de Chagas/tratamento farmacológico , Inibidores das Enzimas do Citocromo P-450 , Modelos Animais de Doenças , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/uso terapêutico , Imidazóis/farmacologia , Doença Aguda , Animais , Doença de Chagas/parasitologia , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Feminino , Imidazóis/síntese química , Imidazóis/química , Imidazóis/uso terapêutico , Camundongos , Camundongos Endogâmicos BALB C , Modelos Moleculares , Estrutura Molecular , Testes de Sensibilidade Parasitária , Esterol 14-Desmetilase , Relação Estrutura-Atividade , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/enzimologiaRESUMO
The signaling enzyme phospholipase D (PLD) and the lipid second messenger it generates, phosphatidic acid (PA), are implicated in many cell biological processes, including Ras activation, cell spreading, stress fiber formation, chemotaxis, and membrane vesicle trafficking. PLD production of PA is inhibited by the primary alcohol 1-butanol, which has thus been widely employed to identify PLD/PA-driven processes. However, 1-butanol does not always effectively reduce PA accumulation, and its use may result in PLD-independent deleterious effects. Consequently, identification of potent specific small-molecule PLD inhibitors would be an important advance for the field. We examine one such here, 5-fluoro-2-indolyl des-chlorohalopemide (FIPI), which was identified recently in an in vitro chemical screen for PLD2 inhibitors, and show that it rapidly blocks in vivo PA production with subnanomolar potency. We were surprised to find that several biological processes blocked by 1-butanol are not affected by FIPI, suggesting the need for re-evaluation of proposed roles for PLD. However, FIPI does inhibit PLD regulation of F-actin cytoskeleton reorganization, cell spreading, and chemotaxis, indicating potential utility for it as a therapeutic for autoimmunity and cancer metastasis.
Assuntos
Movimento Celular/efeitos dos fármacos , Quimiotaxia/efeitos dos fármacos , Domperidona/análogos & derivados , Fosfolipase D/antagonistas & inibidores , Animais , Células CHO , Movimento Celular/fisiologia , Quimiotaxia/fisiologia , Cricetinae , Cricetulus , Domperidona/química , Domperidona/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Células HL-60 , Humanos , Camundongos , Células NIH 3T3 , Fosfolipase D/metabolismoRESUMO
A new class of 2-oxo-tetrahydro-1,8-naphthyridine-based protein farnesyltransferase inhibitors were synthesized and found to inhibit protein farnesyltransferase from the malaria parasite with potencies in the low nanomolar range. The compounds were much less potent on mammalian protein prenyltransferases. Two of the compounds block the growth of malaria in culture with potencies in the sub-micromolar range. Some of the compounds were found to be much more metabolically stable than previously described tetrahydroquinoline-based protein farnesyltransferase inhibitors.
Assuntos
Alquil e Aril Transferases/antagonistas & inibidores , Antimaláricos/farmacologia , Inibidores Enzimáticos/farmacologia , Naftiridinas/farmacologia , Animais , Antimaláricos/farmacocinética , Desenho de Fármacos , Inibidores Enzimáticos/farmacocinética , Naftiridinas/farmacocinética , Plasmodium falciparum/efeitos dos fármacos , RatosRESUMO
Substituted tetrahydroquinolines (THQs) have been previously identified as inhibitors of mammalian protein farnesyltransferase (PFT). Previously we showed that blocking PFT in the malaria parasite led to cell death and that THQ-based inhibitors are the most potent among several structural classes of PFT inhibitors (PFTIs). We have prepared 266 THQ-based PFTIs and discovered several compounds that inhibit the malarial enzyme in the sub- to low-nanomolar range and that block the growth of the parasite (P. falciparum) in the low-nanomolar range. This body of structure-activity data can be rationalized in most cases by consideration of the X-ray structure of one of the THQs bound to mammalian PFT together with a homology structural model of the malarial enzyme. The results of this study provide the basis for selection of antimalarial PFTIs for further evaluation in preclinical drug discovery assays.