RESUMO
Plant-based therapies date back centuries. Cannabis sativa is one such plant that was used medicinally up until the early part of the 20th century. Although rich in diverse and interesting phytochemicals, cannabis was largely ignored by the modern scientific community due to its designation as a schedule 1 narcotic and restrictions on access for research purposes. There was renewed interest in the early 1990s when the endocannabinoid system (ECS) was discovered, a complex network of signaling pathways responsible for physiological homeostasis. Two key components of the ECS, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), were identified as the molecular targets of the phytocannabinoid Δ9-tetrahydrocannabinol (Δ9-THC). Restrictions on access to cannabis have eased worldwide, leading to a resurgence in interest in the therapeutic potential of cannabis. Much of the focus has been on the two major constituents, Δ9-THC and cannabidiol (CBD). Cannabis contains over 140 phytocannabinoids, although only a handful have been tested for pharmacological activity. Many of these minor cannabinoids potently modulate receptors, ionotropic channels, and enzymes associated with the ECS and show therapeutic potential individually or synergistically with other phytocannabinoids. The following review will focus on the pharmacological developments of the next generation of phytocannabinoid therapeutics.
Assuntos
Canabidiol/farmacologia , Cannabis/química , Dronabinol/farmacologia , Compostos Fitoquímicos/farmacologia , Transdução de Sinais/efeitos dos fármacos , Canabinoides/farmacologia , Dronabinol/química , Endocanabinoides , HumanosRESUMO
Previous efforts from our laboratory demonstrated that (E)-3-((3-(E)-vinylaryl)-1H-indazol-6-yl)methylene)-indolin-2-ones are potent PLK4 inhibitors with in vivo anticancer efficacy upon IP dosing. As part of a continued effort to develop selective and orally efficacious inhibitors, we examined variations on this theme wherein 'directly-linked' aromatics, pendant from the indazole core, replace the arylvinyl moiety. Herein, we describe the design and optimization of this series which was ultimately superseded by (3-aryl-1H-indazol-6-yl)spiro[cyclopropane-1,3'-indolin]-2'-ones. The latter compounds are potent and selective inhibitors of PLK4 with oral exposure in rodents and in vivo anticancer activity. Compound 13b, in particular, has a bioavailability of 22% and achieved a 96% tumor growth inhibition in an MDA-MB-468 xenograft study.
Assuntos
Antineoplásicos/farmacologia , Indóis/química , Indóis/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Administração Oral , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/farmacocinética , Área Sob a Curva , Linhagem Celular Tumoral , Desenho de Fármacos , Xenoenxertos , Humanos , Indóis/administração & dosagem , Indóis/farmacocinética , Camundongos , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/farmacocinética , RatosRESUMO
This work describes a scaffold hopping exercise that begins with known imidazo[1,2-a]pyrazines, briefly explores pyrazolo[1,5-a][1,3,5]triazines, and ultimately yields pyrazolo[1,5-a]pyrimidines as a novel class of potent TTK inhibitors. An X-ray structure of a representative compound is consistent with 1(1)/2 type inhibition and provides structural insight to aid subsequent optimization of in vitro activity and physicochemical and pharmacokinetic properties. Incorporation of polar moieties in the hydrophobic and solvent accessible regions modulates physicochemical properties while maintaining potency. Compounds with enhanced oral exposure were identified for xenograft studies. The work culminates in the identification of a potent (TTK K i = 0.1 nM), highly selective, orally bioavailable anticancer agent (CFI-402257) for IND enabling studies.
RESUMO
The acetamido and carboxamido substituted 3-(1H-indazol-3-yl)benzenesulfonamides are potent TTK inhibitors. However, they display modest ability to attenuate cancer cell growth; their physicochemical properties, and attendant pharmacokinetic parameters, are not drug-like. By eliminating the polar 3-sulfonamide group and grafting a heterocycle at the 4 position of the phenyl ring, potent inhibitors with oral exposure were obtained. An X-ray cocrystal structure and a refined binding model allowed for a structure guided approach. Systematic optimization resulted in novel TTK inhibitors, namely 3-(4-(heterocyclyl)phenyl)-1H-indazole-5-carboxamides. Compounds incorporating the 3-hydroxy-8-azabicyclo[3.2.1]octan-8-yl bicyclic system were potent (TTK IC50 < 10 nM, HCT116 GI50 < 0.1 µM), displayed low off-target activity (>500×), and microsomal stability (T(1/2) > 30 min). A subset was tested in rodent PK and mouse xenograft models of human cancer. Compound 75 (CFI-401870) recapitulated the phenotype of TTK RNAi, demonstrated in vivo tumor growth inhibition upon oral dosing, and was selected for preclinical evaluation.
Assuntos
Proteínas de Ciclo Celular/antagonistas & inibidores , Neoplasias do Colo/tratamento farmacológico , Indazóis/química , Indazóis/uso terapêutico , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/antagonistas & inibidores , Administração Oral , Animais , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Colo/efeitos dos fármacos , Colo/enzimologia , Colo/patologia , Neoplasias do Colo/enzimologia , Neoplasias do Colo/patologia , Cristalografia por Raios X , Feminino , Humanos , Indazóis/administração & dosagem , Indazóis/farmacologia , Camundongos Nus , Modelos Moleculares , Inibidores de Proteínas Quinases/administração & dosagem , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismoRESUMO
Previous publications from our laboratory have introduced novel inhibitors of Polo-like kinase 4 (PLK4), a mitotic kinase identified as a potential target for cancer therapy. The search for potent and selective PLK4 inhibitors yielded (E)-3-((1Hindazol-6-yl)methylene)indolin-2-ones, which were superseded by the bioisosteric 2-(1H-indazol-6-yl)spiro[cyclopropane-1,3'-indolin]-2'-ones, e.g., 3. The later scaffold confers improved drug-like properties and incorporates two stereogenic centers. This work reports the discovery of a novel one-pot double SN2 displacement reaction for the stereoselective installation of the desired asymmetric centers and confirms the stereochemistry of the most potent stereoisomer, e.g., 44. Subsequent work keys on the optimization of the oral exposure of nanomolar PLK4 inhibitors with potent cancer cell growth inhibitory activity. A short list of compounds with superior potency and pharmacokinetic properties in rodents and dogs was studied in mouse models of tumor growth. We conclude with the identification of compound 48 (designated CFI-400945) as a novel clinical candidate for cancer therapy.
Assuntos
Antineoplásicos/farmacologia , Indazóis/farmacologia , Indóis/farmacologia , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/análise , Administração Oral , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Disponibilidade Biológica , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cães , Relação Dose-Resposta a Droga , Descoberta de Drogas , Feminino , Células HCT116 , Humanos , Indazóis/química , Indazóis/farmacocinética , Indóis/química , Indóis/farmacocinética , Células MCF-7 , Masculino , Camundongos Nus , Camundongos SCID , Modelos Químicos , Estrutura Molecular , Neoplasias/metabolismo , Neoplasias/patologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacocinética , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Ratos , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Polo-like kinase 4 (PLK4), a unique member of the polo-like kinase family of serine-threonine kinases, is a master regulator of centriole duplication that is important for maintaining genome integrity. Overexpression of PLK4 is found in several human cancers and is linked with a predisposition to tumorigenesis. Previous efforts to identify potent and efficacious PLK4 inhibitors resulted in the discovery of (E)-3-((1H-indazol-6-yl)methylene)indolin-2-ones, which are superseded by the bioisosteric 2-(1H-indazol-6-yl)spiro[cyclopropane-1,3'-indolin]-2'-ones reported herein. Optimization of this new cyclopropane-linked series was based on a computational model of a PLK4 X-ray structure and SAR attained from the analogous alkenelinked series. The racemic cyclopropane-linked compounds showed PLK4 affinity and antiproliferative activity comparable to their alkene-linked congeners with improved hysicochemical, ADME, and pharmacokinetic properties. Positive xenograft results from the MDA-MB-468 human breast cancer xenograft model for compound 18 support the investigation of PLK4 inhibitors as anticancer therapeutics. A PLK4 X-ray co-structure with racemate 18 revealed preferential binding of the 1R,2S enantiomer to the PLK4 kinase domain.
Assuntos
Antineoplásicos/farmacologia , Indóis/farmacologia , Neoplasias/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Compostos de Espiro/farmacologia , Administração Oral , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Disponibilidade Biológica , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Desenho de Fármacos , Descoberta de Drogas , Ensaios de Seleção de Medicamentos Antitumorais , Células HCT116 , Humanos , Indóis/química , Indóis/farmacocinética , Células MCF-7 , Camundongos , Modelos Químicos , Estrutura Molecular , Neoplasias/metabolismo , Neoplasias/patologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacocinética , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Ratos , Compostos de Espiro/química , Compostos de Espiro/farmacocinética , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
In the search for new antibacterial agents, the enzyme FabI has been identified as an attractive target. Employing a structure guided approach, the previously reported ene-amide series of FabI inhibitors were expanded to include 2,3,4,5-tetrahydro-1H-pyrido[2,3-b and e][1,4]diazepines. These novel series incorporate additional H-bonding functions and can be more water soluble than their naphthyridinone progenitors; diazepine 16c is shown to be efficacious in a mouse infection model.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Azepinas/química , Azepinas/farmacologia , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/antagonistas & inibidores , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/metabolismo , Animais , Antibacterianos/uso terapêutico , Azepinas/uso terapêutico , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Infecções por Escherichia coli/tratamento farmacológico , Camundongos , Modelos Moleculares , Ligação Proteica , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/enzimologiaRESUMO
Spiropiperidine naphthyridinone inhibitors of Staphylococcus aureus and Escherichia coli FabI have been prepared. Compounds 14a and 14c were identified as having sub-nanomolar E. coli FabI activity and are among the most potent FabI inhibitors yet described. The structural model of 14a bound to E. coli FabI is shown.
Assuntos
Antibacterianos/farmacologia , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/antagonistas & inibidores , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/metabolismo , Escherichia coli/enzimologia , Naftiridinas/farmacologia , Piperidinas/farmacologia , Compostos de Espiro/farmacologia , Staphylococcus aureus/enzimologia , Antibacterianos/química , Domínio Catalítico , Enoil-(Proteína de Transporte de Acila) Redutase (NADH)/química , Modelos Moleculares , Naftiridinas/química , Piperidinas/química , Ligação Proteica , Compostos de Espiro/química , Relação Estrutura-AtividadeRESUMO
The melanocortin receptors have been implicated as potential targets for a number of important therapeutic indications, including inflammation, sexual dysfunction, and obesity. We identified compound 1, an arylpiperazine attached to the dipeptide H-d-Tic-d-p-Cl-Phe-OH, as a novel melanocortin subtype-4 receptor (MC4R) agonist through iterative directed screening of nonpeptidyl G-protein-coupled receptor biased libraries. Structure-activity relationship (SAR) studies demonstrated that substitutions at the ortho position of the aryl ring improved binding and functional potency. For example, the o-isopropyl-substituted compound 29 (K(i) = 720 nM) possessed 9-fold better binding affinity compared to the unsubstituted aryl ring (K(i) = 6600 nM). Sulfonamide 39 (K(i) = 220 nM) fills this space with a polar substituent, resulting in a further 2-fold improvement in binding affinity. The most potent compounds such as the diethylamine 44 (K(i) = 60 nM) contain a basic group at this position. Basic heterocycles such as the imidazole 50 (K(i) = 110 nM) were similarly effective. We also demonstrated good oral bioavailability for sulfonamide 39.
Assuntos
Piperazinas/síntese química , Receptor Tipo 4 de Melanocortina/agonistas , Animais , Ligação Competitiva , Disponibilidade Biológica , Linhagem Celular , AMP Cíclico/biossíntese , Humanos , Ligantes , Piperazinas/química , Piperazinas/farmacologia , Ensaio Radioligante , Ratos , Ratos Endogâmicos F344 , Receptor Tipo 4 de Melanocortina/metabolismo , Relação Estrutura-AtividadeRESUMO
Binding of methionine to methionyl-tRNA synthetase (MetRS) is known to promote conformational changes within the active site. However, the contribution of these rearrangements to enzyme catalysis is not fully understood. In this study, several methionine and methionyl adenylate analogues were diffused into crystals of the monomeric form of Escherichia coli methionyl-tRNA synthetase. The structures of the corresponding complexes were solved at resolutions below 1.9A and compared to those of the enzyme free or complexed with methionine. Residues Y15 and W253 play key roles in the strength of the binding of the amino acid and of its analogues. Indeed, full motions of these residues are required to recover the maximum in free energy of binding. Residue Y15 also controls the size of the hydrophobic pocket where the amino acid side-chain interacts. H301 appears to participate to the specific recognition of the sulphur atom of methionine. Complexes with methionyl adenylate analogues illustrate the shielding by MetRS of the region joining the methionine and adenosine moieties. Finally, the structure of MetRS complexed to a methionine analogue mimicking the tetrahedral carbon of the transition state in the aminoacylation reaction was solved. On the basis of this model, we propose that, in response to the binding of the 3'-end of tRNA, Y15 moves again in order to deshield the anhydride bond in the natural adenylate.
Assuntos
Monofosfato de Adenosina/análogos & derivados , Monofosfato de Adenosina/química , Escherichia coli/metabolismo , Metionina tRNA Ligase/química , Metionina/análogos & derivados , Metionina/química , Conformação Proteica , Monofosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Catálise , Cristalografia por Raios X , Metionina/metabolismo , Metionina tRNA Ligase/metabolismo , Dados de Sequência Molecular , Estrutura Molecular , Ligação Proteica , Alinhamento de SequênciaRESUMO
The increasing need for new antibiotics to overcome rapidly developing resistance mechanisms observed in clinical isolates of Gram-positive and Gram-negative eubacteria has placed critical emphasis on the search for new antibacterial enzyme targets and the structural and mechanistic investigation of such targets. Among these potential targets, the enzymes responsible for integrating the amino acid methionine into proteins, along with its subsequent post-translational modification and repair, have emerged as promising candidates for the development of novel antibiotics. As well, there is increasing evidence for the importance of several of these enzymes in the development of anti-cancer, anti-parasitic, and anti-atherosclerotic drugs. Within the last three years, the crystal structures of all of these enzymes have been determined, which offers an unprecedented source of structural information for inhibitor design. The development of combinatorial chemistry and high throughput screening procedures has quickly provided several potent, specific inhibitors for a number of these enzymes, particularly the peptide deformylase, methionine aminopeptidase, and methionyl-tRNA synthetase enzymes. This review critically analyzes the future potential for inhibition of enzymes in this pathway, allowing for a pragmatic view of the success of inhibitor developments and highlighting areas in which further investigations are warranted.
Assuntos
Amidoidrolases , Desenho de Fármacos , Inibidores Enzimáticos/química , Metionina/metabolismo , Aminopeptidases/antagonistas & inibidores , Animais , Bovinos , Escherichia coli/enzimologia , Humanos , Hidroximetil e Formil Transferases/antagonistas & inibidores , Metionina Sulfóxido Redutases , Metionina tRNA Ligase/antagonistas & inibidores , Metionil Aminopeptidases , Modelos Moleculares , Oxirredutases/antagonistas & inibidores , Ligação Proteica , Relação Estrutura-AtividadeRESUMO
A phosphonic acid analogue of S-adenosyl-L-homocysteine was prepared by a novel method and the epimeric mixture separated. Preliminary studies indicate that each epimer causes time-dependent inactivation of S-adenosyl-L-homocysteine hydrolase, however each presented distinct kinetic characteristics.