RESUMO
Overexpression of PIM 1, 2, and 3 kinases is frequently observed in many malignancies. Previously, we discovered a potent and selective pan-PIM kinase inhibitor, compound 2, currently in phase I clinical trials. In this work, we were interested in replacing the amino group on the cyclohexane ring in compound 2 with a hydroxyl group. Structure-based drug design led to cellularly potent but metabolically unstable tetra-substituted cyclohexyl diols. Efforts on the reduction of Log D by introducing polar heterocycles improved metabolic stability. Incorporating fluorine to the tetra-substituted cyclohexyl diol moiety further reduced Log D, resulting in compound 14, a cellularly potent tetra-substituted cyclohexyl diol inhibitor with moderate metabolic stability and good permeability. We also describe the development of efficient and scalable synthetic routes toward synthetically challenging tetra-substituted cyclohexyl diol compounds. In particular, intermediate 36 was identified as a versatile intermediate, enabling a large-scale synthesis of highly substituted cyclohexane derivatives.
Assuntos
Cicloexanóis/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Linhagem Celular Tumoral , Cicloexanóis/síntese química , Cicloexanóis/metabolismo , Humanos , Microssomos Hepáticos/metabolismo , Simulação de Acoplamento Molecular , Estrutura Molecular , Ligação Proteica , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas c-pim-1/metabolismo , Relação Estrutura-AtividadeRESUMO
The lipopolysaccharide biosynthesis pathway is considered an attractive drug target against the rising threat of multi-drug-resistant Gram-negative bacteria. Here, we report two novel small-molecule inhibitors (compounds 1 and 2) of the acyltransferase LpxA, the first enzyme in the lipopolysaccharide biosynthesis pathway. We show genetically that the antibacterial activities of the compounds against efflux-deficient Escherichia coli are mediated by LpxA inhibition. Consistently, the compounds inhibited the LpxA enzymatic reaction in vitro. Intriguingly, using biochemical, biophysical, and structural characterization, we reveal two distinct mechanisms of LpxA inhibition; compound 1 is a substrate-competitive inhibitor targeting apo LpxA, and compound 2 is an uncompetitive inhibitor targeting the LpxA/product complex. Compound 2 exhibited more favorable biological and physicochemical properties than compound 1 and was optimized using structural information to achieve improved antibacterial activity against wild-type E. coli. These results show that LpxA is a promising antibacterial target and imply the advantages of targeting enzyme/product complexes in drug discovery.
Assuntos
Aciltransferases/antagonistas & inibidores , Antibacterianos/farmacologia , Inibidores Enzimáticos/farmacologia , Imidazóis/farmacologia , Pirazóis/farmacologia , Aciltransferases/metabolismo , Antibacterianos/metabolismo , Cristalografia por Raios X , Inibidores Enzimáticos/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/enzimologia , Imidazóis/metabolismo , Testes de Sensibilidade Microbiana , Ligação Proteica , Pirazóis/metabolismoRESUMO
LpxD, acyl-ACP-dependent N-acyltransferase, is the third enzyme of lipid A biosynthesis in Gram-negative bacteria. A recent probe-based screen identified several compounds, including 6359-0284 (compound 1), that inhibit the enzymatic activity of Escherichia coli (E. coli) LpxD. Here, we use these inhibitors to chemically validate LpxD as an attractive antibacterial target. We first found that compound 1 was oxidized in solution to the more stable aromatized tetrahydro-pyrazolo-quinolinone compound 1o. From the Escherichia coli strain deficient in efflux, we isolated a mutant that was less susceptible to compound 1o and had an lpxD missense mutation (Gly268Cys), supporting the cellular on-target activity. Using surface plasma resonance, we showed direct binding to E. coli LpxD for compound 1o and other reported LpxD inhibitors in vitro. Furthermore, we determined eight cocrystal structures of E. coli LpxD/inhibitor complexes. These costructures pinpointed the 4'-phosphopantetheine binding site as the common ligand binding hotspot, where hydrogen bonds to Gly269 and/or Gly287 were important for inhibitor binding. In addition, the LpxD/compound 1o costructure rationalized the reduced activity of compound 1o in the LpxDGly268Cys mutant. Moreover, we obtained the LpxD structure in complex with a previously reported LpxA/LpxD dual targeting peptide inhibitor, RJPXD33, providing structural rationale for the unique dual targeting properties of this peptide. Given that the active site residues of LpxD are conserved in multidrug resistant Enterobacteriaceae, this work paves the way for future LpxD drug discovery efforts combating these Gram-negative pathogens.
Assuntos
Aciltransferases , Proteínas de Escherichia coli , Escherichia coli , Aciltransferases/antagonistas & inibidores , Aciltransferases/genética , Sítios de Ligação , Escherichia coli/enzimologia , Escherichia coli/genética , Proteínas de Escherichia coli/antagonistas & inibidores , Lipídeo A , LipopolissacarídeosRESUMO
The discovery of a highly potent and selective small molecule inhibitor 9 for in vitro target validation of MNK1/2 kinases is described. The aminopyrazine benzimidazole series was derived from an HTS hit and optimized by utilization of a docking model, conformation analysis, and binding pocket comparison against antitargets.
Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Sítios de Ligação , Células CACO-2/efeitos dos fármacos , Desenho de Fármacos , Ensaios de Triagem em Larga Escala/métodos , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/química , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Simulação de Acoplamento Molecular , Permeabilidade , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Solubilidade , Relação Estrutura-AtividadeRESUMO
The Pim proteins (1, 2 and 3) are serine/threonine kinases that have been found to be upregulated in many hematological malignancies and solid tumors. As a result of overlapping functions among the three isoforms, inhibition of all three Pim kinases has become an attractive strategy for cancer therapy. Herein we describe our efforts in identifying potent pan-PIM inhibitors that are derived from our previously reported pyridyl carboxamide scaffold as part of a medicinal chemistry strategy to address metabolic stability.
Assuntos
Amidas/farmacologia , Desenho de Fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Amidas/química , Cristalografia por Raios X , Relação Estrutura-AtividadeRESUMO
Alterations in PI3K/AKT signaling are known to be implicated with tumorigenesis. The PI3 kinases family of lipid kinases has been an attractive therapeutic target for cancer treatment. Imidazopyridine compound 1, a potent, selective, and orally available pan-PI3K inhibitor, identified by scaffold morphing of a benzothiazole hit, was further optimized in order to achieve efficacy in a PTEN-deleted A2780 ovarian cancer mouse xenograft model. With a hypothesis that a planar conformation between the core and the 6-heteroaryl ring will allow for the accommodation of larger 5'-substituents in a hydrophobic area under P-loop, SAR efforts focused on 5'-alkoxy heteroaryl rings at the 6-position of imidazopyridine and imidazopyridazine cores that have the same dihedral angle of zero degrees. 6'-Alkoxy 5'-aminopyrazines in the imidazopyridine series were identified as the most potent compounds in the A2780 cell line. Compound 14 with 1,1,1-trifluoroisopropoxy group at 6'-position demonstrated excellent potency and selectivity, good oral exposure in rats and in vivo efficacy in A2780 tumor-bearing mouse. Also, we disclose the X-ray co-crystal structure of one enantiomer of compound 14 in PI3Kα, confirming that the trifluoromethyl group fits nicely in the hydrophobic hot spot under P-loop.
Assuntos
Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Piridinas/química , Piridinas/farmacologia , Animais , Antineoplásicos/química , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Sítios de Ligação , Linhagem Celular Tumoral , Cristalografia por Raios X , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Ativação Enzimática/efeitos dos fármacos , Feminino , Meia-Vida , Xenoenxertos , Humanos , Camundongos , Simulação de Acoplamento Molecular , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Fosfatidilinositol 3-Quinases/metabolismo , Inibidores de Proteínas Quinases/farmacocinética , Inibidores de Proteínas Quinases/uso terapêutico , Estrutura Terciária de Proteína , Piridinas/farmacocinética , Piridinas/uso terapêutico , Ratos , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Pan proviral insertion site of Moloney murine leukemia (PIM) 1, 2, and 3 kinase inhibitors have recently begun to be tested in humans to assess whether pan PIM kinase inhibition may provide benefit to cancer patients. Herein, the synthesis, in vitro activity, in vivo activity in an acute myeloid leukemia xenograft model, and preclinical profile of the potent and selective pan PIM kinase inhibitor compound 8 (PIM447) are described. Starting from the reported aminopiperidyl pan PIM kinase inhibitor compound 3, a strategy to improve the microsomal stability was pursued resulting in the identification of potent aminocyclohexyl pan PIM inhibitors with high metabolic stability. From this aminocyclohexyl series, compound 8 entered the clinic in 2012 in multiple myeloma patients and is currently in several phase 1 trials of cancer patients with hematological malignancies.
Assuntos
Leucemia Mieloide Aguda/tratamento farmacológico , Ácidos Picolínicos/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Amidas/síntese química , Amidas/química , Amidas/uso terapêutico , Animais , Linhagem Celular Tumoral , Halogenação , Humanos , Leucemia Mieloide Aguda/metabolismo , Camundongos , Modelos Moleculares , Ácidos Picolínicos/síntese química , Ácidos Picolínicos/química , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-pim-1/metabolismoRESUMO
A series of structure based drug design hypotheses and focused screening efforts led to the identification of tetrahydropyrrolo-diazepenones with striking potency against ERK2 kinase. The role of fluorination in mitigating microsomal clearance was systematically explored. Ultimately, it was found that fluorination of a cyclopentanol substructure provided significant improvement in both potency and human metabolic stability.
Assuntos
Azepinas/farmacologia , Compostos Heterocíclicos com 2 Anéis/farmacologia , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Pirróis/farmacologia , Azepinas/química , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Compostos Heterocíclicos com 2 Anéis/química , Humanos , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Modelos Moleculares , Estrutura Molecular , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Pirróis/química , Relação Estrutura-AtividadeRESUMO
A series of structure based drug design hypotheses and focused screening efforts drove improvements in the potency and lipophilic efficiency of tetrahydro-pyrazolopyridine based ERK2 inhibitors. Elaboration of a fragment chemical lead established a new lipophilic aryl-Tyr interaction resulting in a substantial potency improvement. Subsequent cleavage of the lipophilic moiety led to reconfiguration of the ligand bound binding cleft. The reconfiguration established a polar contact between a newly liberated N-H and a vicinal Asp, resulting in further improvements in lipophilic efficiency and in vitro clearance.
Assuntos
Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Pirazóis/química , Piridinas/química , Relação Estrutura-Atividade , Trifosfato de Adenosina/metabolismo , Animais , Ácido Aspártico/química , Ácido Aspártico/metabolismo , Sítios de Ligação , Cristalografia por Raios X , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Humanos , Ligantes , Proteína Quinase 1 Ativada por Mitógeno/química , Modelos Moleculares , Conformação Proteica , RatosRESUMO
PURPOSE: PIM kinases have been shown to act as oncogenes in mice, with each family member being able to drive progression of hematologic cancers. Consistent with this, we found that PIMs are highly expressed in human hematologic cancers and show that each isoform has a distinct expression pattern among disease subtypes. This suggests that inhibitors of all three PIMs would be effective in treating multiple hematologic malignancies. EXPERIMENTAL DESIGN: Pan-PIM inhibitors have proven difficult to develop because PIM2 has a low Km for ATP and, thus, requires a very potent inhibitor to effectively block the kinase activity at the ATP levels in cells. We developed a potent and specific pan-PIM inhibitor, LGB321, which is active on PIM2 in the cellular context. RESULTS: LGB321 is active on PIM2-dependent multiple myeloma cell lines, where it inhibits proliferation, mTOR-C1 signaling and phosphorylation of BAD. Broad cancer cell line profiling of LGB321 demonstrates limited activity in cell lines derived from solid tumors. In contrast, significant activity in cell lines derived from diverse hematological lineages was observed, including acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), multiple myeloma and non-Hodgkin lymphoma (NHL). Furthermore, we demonstrate LGB321 activity in the KG-1 AML xenograft model, in which modulation of pharmacodynamics markers is predictive of efficacy. Finally, we demonstrate that LGB321 synergizes with cytarabine in this model. CONCLUSIONS: We have developed a potent and selective pan-PIM inhibitor with single-agent antiproliferative activity and show that it synergizes with cytarabine in an AML xenograft model. Our results strongly support the development of Pan-PIM inhibitors to treat hematologic malignancies.
Assuntos
Neoplasias Hematológicas/terapia , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas c-pim-1/genética , Proteínas Proto-Oncogênicas/genética , Animais , Linhagem Celular Tumoral , Neoplasias Hematológicas/genética , Neoplasias Hematológicas/patologia , Humanos , Camundongos , Fosforilação , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Transdução de Sinais/genética , Serina-Treonina Quinases TOR/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
PI3 kinases are a family of lipid kinases mediating numerous cell processes such as proliferation, migration and differentiation. The PI3 Kinase pathway is often de-regulated in cancer through PI3Kα overexpression, gene amplification, mutations and PTEN phosphatase deletion. PI3K inhibitors represent therefore an attractive therapeutic modality for cancer treatment. Herein we describe how the potency of a benzothiazole fragment hit was quickly improved based on structural information and how this early chemotype was further optimized through scaffold hopping. This effort led to the identification of a series of 2-acetamido-5-heteroaryl imidazopyridines showing potent in vitro activity against all class I PI3Ks and attractive pharmacokinetic properties.
Assuntos
Compostos Azo/síntese química , Inibidores de Fosfoinositídeo-3 Quinase , Piridinas/síntese química , Piridinas/farmacologia , Compostos Azo/química , Compostos Azo/farmacologia , Benzotiazóis/química , Benzotiazóis/farmacologia , Linhagem Celular Tumoral , Ativação Enzimática/efeitos dos fármacos , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Feminino , Humanos , Imidas/síntese química , Imidas/química , Imidas/farmacologia , Concentração Inibidora 50 , Modelos Moleculares , Piridinas/química , Solubilidade , Relação Estrutura-AtividadeRESUMO
Proviral insertion of Moloney virus (PIM) 1, 2, and 3 kinases are serine/threonine kinases that normally function in survival and proliferation of hematopoietic cells. As high expression of PIM1, 2, and 3 is frequently observed in many human malignancies, including multiple myeloma, non-Hodgkins lymphoma, and myeloid leukemias, there is interest in determining whether selective PIM inhibition can improve outcomes of these human cancers. Herein, we describe our efforts toward this goal. The structure guided optimization of a singleton high throughput screening hit in which the potency against all three PIM isoforms was increased >10,000-fold to yield compounds with pan PIM K is < 10 pM, nanomolar cellular potency, and in vivo activity in an acute myeloid leukemia Pim-dependent tumor model is described.
RESUMO
A series of novel 3,5-disubstituted indole derivatives as potent and selective inhibitors of all three members of the Pim kinase family is described. High throughput screen identified a pan-Pim kinase inhibitor with a promiscuous scaffold. Guided by structure-based drug design, SAR of the series afforded a highly selective indole chemotype that was further developed into a potent set of compounds against Pim-1, 2, and 3 (Pim-1 and Pim-3: IC(50)≤2nM and Pim-2: IC(50)≤100nM).
Assuntos
Descoberta de Drogas , Indóis/química , Indóis/farmacologia , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Quinases/efeitos dos fármacos , Concentração Inibidora 50 , Modelos Moleculares , Relação Estrutura-AtividadeRESUMO
[reaction: see text] A highly diastereoselective MgI(2)-mediated ring expansion of methylenecyclopropane amides to functionalized pyrrolidines has been developed using chiral aromatic sulfinimines. The 2,3,4-trisubstituted pyrrolidines were isolated in generally good to excellent yields and in excellent diastereoselectivities for aromatic and heterocyclic sulfinimines.
RESUMO
Ring expansion of secondary methylenecyclopropyl amides in the presence of MgI2 was investigated. Various isomeric five-membered unsaturated lactams were obtained, depending on the character of the substituent Q. The amide group served as a nucleophile in ring closing as well as an activator for ring opening. In the presence of a variety of aryl aldimines or aldehydes, alkylative ring expansion occurred in a single step under mild and neutral conditions leading to gamma'-amino- or -hydroxy-alkylated pyrrol-2-ones. Also, it was shown that a 4-methylpyrrol-2-one could be transformed to a gamma-hydroxy-alkylated product by the use of a direct vinylogous aldol reaction.
RESUMO
We report a novel approach to prepare five- and six-membered heterocyclic compounds via a ring expansion of monoactivated methylenecyclopropanes (MCPs) with aldimines and aldehydes in the presence of MgI(2). Monoactivated MCPs behave as homo-Michael acceptors to afford bifunctional vinylogous enolates in the presence of MgI(2). The carbonyl moiety of the monoactivated MCP dramatically influences the reaction site in the dienolate with aryl aldimines and aldehydes as well as the size of the ring. Excellent divergent selectivity to five- vs. six-membered heterocycles is observed: alpha-alkylation/5-exo-tet cyclization (Z = NPh(2)) vs. gamma-alkylation/6-exo-trig cyclization (Z = 2-oxazolidone). Analogously, the reaction of the MCP imide with alkyl aldimines demonstrates the same selectivity by varying the size of electrophile or the reaction temperature. In addition, we observe the first example of the formation of the gamma-alkylation adduct in the reaction of a vinylogous imide enolate with a carbonyl compound.