RESUMO
We describe a protein proximity inducing therapeutic modality called Regulated Induced Proximity Targeting Chimeras or RIPTACs: heterobifunctional small molecules that elicit a stable ternary complex between a target protein (TP) selectively expressed in tumor cells and a pan-expressed protein essential for cell survival. The resulting co-operative protein-protein interaction (PPI) abrogates the function of the essential protein, thus leading to death selectively in cells expressing the TP. This approach leverages differentially expressed intracellular proteins as novel cancer targets, with the advantage of not requiring the target to be a disease driver. In this chemical biology study, we design RIPTACs that incorporate a ligand against a model TP connected via a linker to effector ligands such as JQ1 (BRD4) or BI2536 (PLK1) or CDK inhibitors such as TMX3013 or dinaciclib. RIPTACs accumulate selectively in cells expressing the HaloTag-FKBP target, form co-operative intracellular ternary complexes, and induce an anti-proliferative response in target-expressing cells.
Assuntos
Antineoplásicos , Proteínas de Ciclo Celular , Bibliotecas de Moléculas Pequenas , Humanos , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/farmacologia , Bibliotecas de Moléculas Pequenas/síntese química , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Neoplasias/patologia , Proliferação de Células/efeitos dos fármacos , Triazóis/química , Triazóis/farmacologia , Quinase 1 Polo-Like , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Azepinas/farmacologia , Azepinas/química , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Fatores de Transcrição/metabolismo , Fatores de Transcrição/antagonistas & inibidores , Indolizinas/química , Indolizinas/farmacologia , Linhagem Celular Tumoral , Compostos Bicíclicos Heterocíclicos com Pontes/química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Ligantes , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/síntese química , Compostos Heterocíclicos com 2 Anéis/farmacologia , Compostos Heterocíclicos com 2 Anéis/química , Compostos Heterocíclicos com 2 Anéis/síntese química , Proteínas Nucleares/metabolismo , Proteínas Nucleares/antagonistas & inibidores , Proteínas que Contêm Bromodomínio , Óxidos N-Cíclicos , Compostos de PiridínioRESUMO
While specific cell signaling pathway inhibitors have yielded great success in oncology, directly triggering cancer cell death is one of the great drug discovery challenges facing biomedical research in the era of precision oncology. Attempts to eradicate cancer cells expressing unique target proteins, such as antibody-drug conjugates (ADCs), T-cell engaging therapies, and radiopharmaceuticals have been successful in the clinic, but they are limited by the number of targets given the inability to target intracellular proteins. More recently, heterobifunctional small molecules such as Proteolysis Targeting Chimera (PROTACs) have paved the way for protein proximity inducing therapeutic modalities. Here, we describe a proof-of-concept study using novel heterobifunctional small molecules called Regulated Induced Proximity Targeting Chimeras or RIPTACs, which elicit a stable ternary complex between a target protein selectively expressed in cancer tissue and a pan-expressed protein essential for cell survival. The resulting cooperative protein:protein interaction (PPI) abrogates the function of the essential protein, thus leading to cell death selectively in cells expressing the target protein. This approach not only opens new target space by leveraging differentially expressed intracellular proteins but also has the advantage of not requiring the target to be a driver of disease. Thus, RIPTACs can address non-target mechanisms of resistance given that cell killing is driven by inactivation of the essential protein. Using the HaloTag7-FKBP model system as a target protein, we describe RIPTACs that incorporate a covalent or non-covalent target ligand connected via a linker to effector ligands such as JQ1 (BRD4), BI2536 (PLK1), or multi-CDK inhibitors such as TMX3013 or dinaciclib. We show that these RIPTACs exhibit positive co-operativity, accumulate selectively in cells expressing HaloTag7-FKBP, form stable target:RIPTAC:effector trimers in cells, and induce an anti-proliferative response in target-expressing cells. We propose that RIPTACs are a novel heterobifunctional therapeutic modality to treat cancers that are known to selectively express a specific intracellular protein.
RESUMO
An unprecedented series of organometallic HCV (hepatitis C virus) NS5A (nonstructural 5A protein) replication complex inhibitors that incorporates a 1,1'-ferrocenediyl scaffold was explored. This scaffold introduces the elements of linear flexibility and non-planar topology that are unconventional for this class of inhibitors. Data from 2-D NMR spectroscopic analyses of these complexes in solution support an anti (unstacked) arrangement of the pharmacophoric groups. Several complexes demonstrate single-digit picomolar in vitro activity in an HCV genotype-1b replicon system. One complex to arise from this investigation (10a) exhibits exceptional picomolar activity against HCV genotype 1a and 1b replicons, low hepatocellular cytotoxicity, and good pharmacokinetic properties in rat.
Assuntos
Antivirais/farmacologia , Benzimidazóis/farmacologia , Compostos Ferrosos/farmacologia , Hepacivirus/efeitos dos fármacos , Metalocenos/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Replicação Viral/efeitos dos fármacos , Animais , Antivirais/síntese química , Antivirais/química , Antivirais/farmacocinética , Benzimidazóis/síntese química , Benzimidazóis/química , Benzimidazóis/farmacocinética , Linhagem Celular Tumoral , Compostos Ferrosos/síntese química , Compostos Ferrosos/química , Compostos Ferrosos/farmacocinética , Humanos , Macaca fascicularis , Masculino , Metalocenos/síntese química , Metalocenos/química , Metalocenos/farmacocinética , Microssomos Hepáticos/metabolismo , Estrutura Molecular , Ratos Sprague-Dawley , Relação Estrutura-AtividadeRESUMO
1. Due to its unique C-C and C-H bonding properties, conformational preferences and relative hydrophilicity, the cyclopropyl ring has been used as a synthetic building block in drug discovery to modulate potency and drug-like properties. During an effort to discover inhibitors of the hepatitis C virus non-structural protein 5B with improved potency and genotype-coverage profiles, the use of a pyrimidinylcyclopropylbenzamide moiety linked to a C6-substituted benzofuran or azabenzofuran core scaffold was explored in an effort to balance antiviral potency and metabolic stability. 2. In vitro metabolism studies of two compounds from this C6-substituted series revealed an NADPH-dependent bioactivation pathway leading to the formation of multiple glutathione (GSH) conjugates. Analysis of these conjugates by LC-MS and NMR demonstrated that the cyclopropyl group was the site of bioactivation. Based on the putative structures and molecular weights of the cyclopropyl-GSH conjugates, a multi-step mechanism was proposed to explain the formation of these metabolites by P450. This mechanism involves hydrogen atom abstraction to form a cyclopropyl radical, followed by a ring opening rearrangement and reaction with GSH. 3. These findings provided important information to the medicinal chemistry team which responded by replacing the cyclopropyl ring with a gem-dimethyl group. Subsequent compounds bearing this feature were shown to avert the bioactivation pathways in question.
Assuntos
Antivirais , Benzamidas , Sistema Enzimático do Citocromo P-450/metabolismo , Hepacivirus , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/farmacocinética , Antivirais/farmacologia , Benzamidas/farmacocinética , Benzamidas/farmacologia , Humanos , RatosRESUMO
The development of a series of novel 7-azabenzofurans exhibiting pan-genotype inhibition of HCV NS5B polymerase via binding to the primer grip site is presented. Many challenges, including poor oral bioavailability, high clearance, bioactivation, high human serum shift, and metabolic stability were encountered and overcome through SAR studies. This work culminated in the selection of BMS-986139 (43) as a preclinical candidate.
RESUMO
During a medicinal chemistry campaign to identify inhibitors of the hepatitis C virus nonstructural protein 5B (RNA-dependent RNA polymerase), a bicyclo[1.1.1]pentane was introduced into the chemical scaffold to improve metabolic stability. The inhibitors bearing this feature, 5-(3-(bicyclo[1.1.1]pentan-1-ylcarbamoyl)-4-fluorophenyl)-2-(4-fluorophenyl)-N-methyl-6-(3,3,3-trifluoropropyl)furo[2,3-b]pyridine-3-carboxamide (1) and 5-(3-(bicyclo[1.1.1]pentan-1-ylcarbamoyl)phenyl)-2-(4-fluorophenyl)-N-methyl-6-(3,3,3-trifluoropropyl)furo[2,3-b]pyridine-3-carboxamide (2), exhibited low turnover in incubations with liver S9 or hepatocytes (rat, human), with hydroxylation of the bicyclic moiety being the only metabolic pathway observed. In subsequent disposition studies using bile-duct-cannulated rats, the metabolite profiles of bile samples revealed, in addition to multiple products of bicyclopentane-oxidation, unexpected metabolites characterized by molecular masses that were 181 Da greater than those of 1 or 2. Further LC/MSn and NMR analysis of the isolated metabolite of 1 demonstrated the presence of a phosphocholine (POPC) moiety bound to the methine carbon of the bicyclic moiety through an ester bond. The POPC conjugate of the NS5B inhibitors was assumed to result from two sequential reactions: hydroxylation of the bicyclic methine to a tertiary alcohol and addition of POPC by CDP-choline: 1,2-diacylglycerol cholinephosphotransferase, an enzyme responsible for the final step in the biosynthesis of phosphatidylcholine. However, this pathway could not be recapitulated using CDP-choline-supplemented liver S9 or hepatocytes due to inadequate formation of the hydroxylation product in vitro. The observation of this unexpected pathway prompted concerns about the possibility that 1 and 2 might interfere with routine phospholipid synthesis. These results demonstrate the participation in xenobiotic metabolism of a process whose function is ordinarily limited to the synthesis of endogenous compounds.
RESUMO
The role of fluorine in drug design and development is expanding rapidly as we learn more about the unique properties associated with this unusual element and how to deploy it with greater sophistication. The judicious introduction of fluorine into a molecule can productively influence conformation, pKa, intrinsic potency, membrane permeability, metabolic pathways, and pharmacokinetic properties. In addition, (18)F has been established as a useful positron emitting isotope for use with in vivo imaging technology that potentially has extensive application in drug discovery and development, often limited only by convenient synthetic accessibility to labeled compounds. The wide ranging applications of fluorine in drug design are providing a strong stimulus for the development of new synthetic methodologies that allow more facile access to a wide range of fluorinated compounds. In this review, we provide an update on the effects of the strategic incorporation of fluorine in drug molecules and applications in positron emission tomography.
Assuntos
Descoberta de Drogas/métodos , Flúor/química , Flúor/farmacologia , Tomografia por Emissão de Pósitrons/métodos , Animais , Flúor/metabolismo , Flúor/farmacocinética , Radioisótopos de Flúor/química , Halogenação , Humanos , Modelos Moleculares , Conformação MolecularRESUMO
Efforts investigating spatially comparative alternates of the ethylene-bridged piperazine in BMS-791325 that would offer a maintained or improved virologic and pharmacokinetic profile have been multifaceted. One foray involved the utilization of various octahydropyrrolo[3,4-c]pyrrole propellanes. Many of the propellane analogs described in this work exhibited better than targeted potency (less than 20 nM). Additionally, improved exposure in rats was achieved through the employment of two newly invented and now readily accessible carbon bridged propellanes as compared to their heteroatom bridged analogs.
Assuntos
Antivirais/química , Antivirais/farmacocinética , Hepacivirus , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Benzazepinas/química , Indóis/química , Estrutura Molecular , RatosRESUMO
This report details the invention of a method to enable syntheses of psychotrimine (1) and the kapakahines F and B (2, 3) on a gram scale and in a minimum number of steps. Mechanistic inquiries are presented for the key enabling quaternization of indole at the C3 position by electrophilic attack of an activated aniline species. Excellent chemo-, regio-, and diastereoselectivities are observed for reactions with o-iodoaniline, an indole cation equivalent. Additionally, the scope of this reaction is broad with respect to the tryptamine and aniline components. The anti-cancer profiles of 1-3 have also been evaluated.
Assuntos
Compostos de Anilina/química , Dimerização , Indóis/química , Indóis/síntese química , Nitrogênio/química , Peptídeos Cíclicos/química , Peptídeos Cíclicos/síntese química , Linhagem Celular Tumoral , Humanos , Alcaloides Indólicos/síntese química , Alcaloides Indólicos/química , Alcaloides Indólicos/farmacologia , Indóis/farmacologia , Concentração Inibidora 50 , Oxirredução , Peptídeos Cíclicos/farmacologia , Estereoisomerismo , Especificidade por Substrato , Triptaminas/síntese química , Triptaminas/química , Triptaminas/farmacologiaRESUMO
The putative reductive activation chemistry of the diazoparaquinone antibiotics was modeled with Bu(3)Sn-H and prekinamycin dimethyl ether along with prekinamycin itself. Reaction in various combinations of aromatic solvents, with and without the nucleophile benzylmercaptan present, led to isolation of both radical-trapping arene adducts and nucleophilic capture benzyl thioether products. On the basis of these product distribution studies, the intermediacies of, first, a cyclopentenyl radical and, next, an orthoquinonemethide electrophile are postulated.
Assuntos
Anti-Infecciosos/química , Quinonas/química , Anti-Infecciosos/farmacologia , Quinonas/farmacologiaRESUMO
Treatment of the representative diazoparaquinone prekinamycin dimethyl ether with Bu3SnH/AIBN in aromatic solvents furnishes moderate-to-good yields of formal aryl adducts wherein a molecule of solvent is attached to the carbon (C(11)) previously bearing the diazo function. Substituent studies provide evidence in support of a radical aromatic substitution mechanism, in which radical addition to the diazoparaquinone function generates an intermediate C(11) vinylic radical.
Assuntos
Dano ao DNA/efeitos dos fármacos , Quinonas/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , DNA/química , Quinonas/químicaRESUMO
The syntheses of a bis indole and an indole salicylate with the required axial chirality for diazonamide A are reported. Atropselectivity in these biaryl systems is enforced by an sp(3) stereogenic center in a lactone tether in both cases. [structure: see text]