RESUMO
Mycobacterium tuberculosis is responsible for the greatest number of deaths worldwide due to a bacterial agent. We recently identified bortezomib (Velcade; compound 1) as a promising antituberculosis (anti-TB) compound. We showed that compound 1 inhibits the mycobacterial caseinolytic proteases P1 and P2 (ClpP1P2) and exhibits bactericidal activity, and we established compound 1 and ClpP1P2 as an attractive lead/target couple. However, compound 1 is a human-proteasome inhibitor currently approved for cancer therapy and, as such, exhibits significant toxicity. Selective inhibition of the bacterial protease over the human proteasome is desirable in order to maintain antibacterial activity while reducing toxicity. We made use of structural data in order to design a series of dipeptidyl-boronate derivatives of compound 1. We tested these derivatives for whole-cell ClpP1P2 and human-proteasome inhibition as well as bacterial-growth inhibition and identified compounds that were up to 100-fold-less active against the human proteasome but that retained ClpP1P2 and mycobacterial-growth inhibition as well as bactericidal potency. The lead compound, compound 58, had low micromolar ClpP1P2 and anti-M. tuberculosis activity, good aqueous solubility, no cytochrome P450 liabilities, moderate plasma protein binding, and low toxicity in two human liver cell lines, and despite high clearance in microsomes, this compound was only moderately cleared when administered intravenously or orally to mice. Higher-dose oral pharmacokinetics indicated good dose linearity. Furthermore, compound 58 was inhibitory to only 11% of a panel of 62 proteases. Our work suggests that selectivity over the human proteasome can be achieved with a drug-like template while retaining potency against ClpP1P2 and, crucially, anti-M. tuberculosis activity.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Bortezomib/farmacologia , Endopeptidase Clp/antagonistas & inibidores , Mycobacterium smegmatis/efeitos dos fármacos , Mycobacterium tuberculosis/efeitos dos fármacos , Inibidores de Proteassoma/farmacologia , Animais , Proteínas de Bactérias/genética , Bortezomib/farmacocinética , Desenho de Fármacos , Endopeptidase Clp/genética , Camundongos , Testes de Sensibilidade Microbiana , Modelos Moleculares , Mycobacterium smegmatis/genética , Serina Endopeptidases/genética , Tuberculose Pulmonar/tratamento farmacológico , Tuberculose Pulmonar/microbiologiaRESUMO
Dysregulation of translation initiation factor 4E (eIF4E) activity occurs in various cancers. Mitogen-activated protein kinase (MAPK) interacting kinases 1 and 2 (MNK1 and MNK2) play a fundamental role in activation of eIF4E. Structure-activity relationship-driven expansion of a fragment hit led to discovery of dual MNK1 and MNK2 inhibitors based on a novel pyridine-benzamide scaffold. The compounds possess promising in vitro and in vivo pharmacokinetic profiles and show potent on target inhibition of eIF4E phosphorylation in cells.
Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Linhagem Celular Tumoral , Cristalografia por Raios X , Descoberta de Drogas , Fator de Iniciação 4E em Eucariotos/antagonistas & inibidores , Humanos , Modelos Moleculares , Fosforilação , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacocinética , Relação Estrutura-AtividadeRESUMO
SMYD3 is a histone methyltransferase that regulates gene transcription, and its overexpression is associated with multiple human cancers. A novel class of tetrahydroacridine compounds which inhibit SMYD3 through a covalent mechanism of action is identified. Optimization of these irreversible inhibitors resulted in the discovery of 4-chloroquinolines, a new class of covalent warheads. Tool compound 29 exhibits high potency by inhibiting SMYD3's enzymatic activity and showing antiproliferative activity against HepG2 in 3D cell culture. Our findings suggest that covalent inhibition of SMYD3 may have an impact on SMYD3 biology by affecting expression levels, and this warrants further exploration.
RESUMO
[This corrects the article DOI: 10.1021/acsmedchemlett.9b00170.].
RESUMO
The human umbilical cord is a rich source of autologous stem and progenitor cells. Interestingly, subpopulations of these, particularly mesenchymal-like cells from both cord blood and the cord stroma, exhibited a potential to be differentiated into neuron-like cells in culture. Umbilical cord blood stem cells have demonstrated efficacy in reducing lesion sizes and enhancing behavioral recovery in animal models of ischemic and traumatic central nervous system (CNS) injury. Recent findings also suggest that neurons derived from cord stroma mesenchymal cells could alleviate movement disorders in hemiparkinsonian animal models. We review here the neurogenic potential of umbilical cord stem cells and discuss possibilities of their exploitation as an alternative to human embryonic stem cells or neural stem cells for transplantation therapy of traumatic CNS injury and neurodegenerative diseases.
Assuntos
Diferenciação Celular/fisiologia , Doenças do Sistema Nervoso Central/cirurgia , Transplante de Células-Tronco de Sangue do Cordão Umbilical/métodos , Células-Tronco , Cordão Umbilical/transplante , Animais , Sistema Nervoso Central/citologia , Doenças do Sistema Nervoso Central/patologia , Transplante de Células-Tronco de Sangue do Cordão Umbilical/tendências , Humanos , Células-Tronco/citologia , Cordão Umbilical/citologiaRESUMO
Chronic myeloid leukemia (CML) is a myeloproliferative disease caused by bcr-abl1, a constitutively active tyrosine kinase fusion gene responsible for an abnormal proliferation of leukemic stem cells (LSCs). Inhibition of BCR-ABL1 kinase activity offers long-term relief to CML patients. However, for a proportion of them, BCR-ABL1 inhibition will become ineffective at treating the disease, and CML will progress to blast crisis (BC) CML with poor prognosis. BC-CML is often associated with excessive phosphorylated eukaryotic translation initiation factor 4E (eIF4E), which renders LSCs capable of proliferating via self-renewal, oblivious to BCR-ABL1 inhibition. In vivo, eIF4E is exclusively phosphorylated on Ser209 by MNK1/2. Consequently, a selective inhibitor of MNK1/2 should reduce the level of phosphorylated eIF4E and re-sensitize LSCs to BCR-ABL1 inhibition, thus hindering the proliferation of BC LSCs. We report herein the structure-activity relationships and pharmacokinetic properties of a selective MNK1/2 inhibitor clinical candidate, ETC-206, which in combination with dasatinib prevents BC-CML LSC self-renewal in vitro and enhances dasatinib antitumor activity in vivo.
Assuntos
Crise Blástica/tratamento farmacológico , Proliferação de Células , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Animais , Crise Blástica/patologia , Feminino , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Camundongos , Camundongos SCID , Modelos Moleculares , Estrutura Molecular , Conformação Proteica , Inibidores de Proteínas Quinases/química , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Porcupine is an O-acyltransferase that regulates Wnt secretion. Inhibiting porcupine may block the Wnt pathway which is often dysregulated in various cancers. Consequently porcupine inhibitors are thought to be promising oncology therapeutics. A high throughput screen against porcupine revealed several potent hits that were confirmed to be Wnt pathway inhibitors in secondary assays. We developed a pharmacophore model and used the putative bioactive conformation of a xanthine inhibitor for scaffold hopping. The resulting maleimide scaffold was optimized to subnanomolar potency while retaining good physical druglike properties. A preclinical development candidate was selected for which extensive in vitro and in vivo profiling is reported.
Assuntos
Aciltransferases/antagonistas & inibidores , Antineoplásicos/farmacologia , Maleimidas/farmacologia , Proteínas de Membrana/antagonistas & inibidores , Piridazinas/farmacologia , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/síntese química , Antineoplásicos/farmacocinética , Linhagem Celular Tumoral , Inibidores do Citocromo P-450 CYP1A2/administração & dosagem , Inibidores do Citocromo P-450 CYP1A2/síntese química , Inibidores do Citocromo P-450 CYP1A2/farmacocinética , Inibidores do Citocromo P-450 CYP1A2/farmacologia , Inibidores do Citocromo P-450 CYP2D6/administração & dosagem , Inibidores do Citocromo P-450 CYP2D6/síntese química , Inibidores do Citocromo P-450 CYP2D6/farmacocinética , Inibidores do Citocromo P-450 CYP2D6/farmacologia , Inibidores do Citocromo P-450 CYP3A/administração & dosagem , Inibidores do Citocromo P-450 CYP3A/síntese química , Inibidores do Citocromo P-450 CYP3A/farmacocinética , Inibidores do Citocromo P-450 CYP3A/farmacologia , Feminino , Células HEK293 , Ensaios de Triagem em Larga Escala , Humanos , Maleimidas/administração & dosagem , Maleimidas/síntese química , Maleimidas/farmacocinética , Camundongos Endogâmicos BALB C , Camundongos Nus , Microssomos Hepáticos/metabolismo , Piridazinas/administração & dosagem , Piridazinas/síntese química , Piridazinas/farmacocinética , Ratos , Relação Estrutura-Atividade , Via de Sinalização Wnt , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The cis-trans peptidylprolyl isomerase Pin1 plays a critical role in regulating a subset of phosphoproteins by catalyzing conformational changes on the phosphorylated Ser/Thr-Pro motifs. The phosphorylation-directed ubiquitination is one of the major mechanisms to regulate the abundance of p27(Kip1). In this study, we demonstrate that Pin1 catalyzes the cis-trans conformational changes of p27(Kip1) and further mediates its stability through the polyubiquitination mechanism. Our results show that the phosphorylated Thr-187-Pro motif in p27(Kip1) is a key Pin1-binding site. In addition, NMR analyses show that this phosphorylated Thr-187-Pro site undergoes conformational change catalyzed by Pin1. Moreover, in Pin1 knock-out mouse embryonic fibroblasts, p27(Kip1) has a shorter lifetime and displays a higher degree of polyubiquitination than in Pin1 wild-type mouse embryonic fibroblasts, suggesting that Pin1 plays a critical role in regulating p27(Kip1) degradation. Additionally, Pin1 dramatically reduces the interaction between p27(Kip1) and Cks1, possibly via isomerizing the cis-trans conformation of p27(Kip1). Our study thus reveals a novel regulatory mechanism for p27(Kip1) stability and sheds new light on the biological function of Pin1 as a general regulator of protein stability.
Assuntos
Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptidilprolil Isomerase/metabolismo , Ubiquitinação/fisiologia , Motivos de Aminoácidos/fisiologia , Animais , Quinases relacionadas a CDC2 e CDC28/genética , Quinases relacionadas a CDC2 e CDC28/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Inibidor de Quinase Dependente de Ciclina p27/genética , Quinases Ciclina-Dependentes/genética , Quinases Ciclina-Dependentes/metabolismo , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Fibroblastos/citologia , Fibroblastos/metabolismo , Células HeLa , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos , Camundongos Knockout , Peptidilprolil Isomerase de Interação com NIMA , Peptidilprolil Isomerase/genética , Fosforilação/fisiologia , Estabilidade Proteica , Treonina/genética , Treonina/metabolismoRESUMO
The injured adult spinal cord is not conducive for neuronal regeneration and neurogenesis. Engrafted neural precursor cells (NPCs) differentiate largely into astroglia, with only a very small percentage becoming neurons (which might replace injured neurons) or oligodendroglia (which might improve injury induced demyelination of spared neurons). Several recent attempts have been made to enhanced neurogenesis or oligodendroglia differentiation of transplanted NPCs by genetic manipulation. These include exogenous expression of noggin, with the idea of antagonizing the astroglia differentiation promoting Bone Morphogenetic Proteins (BMPs). Direct attempts to enhance neurogenesis have also been made in transgenic over-expression of neurogenic basic helix-loop-helix transcription factors. These experiments resulted in some interesting observations, which we discuss here in the light of recent advances in development of cell-based engraftment therapy for spinal cord injuries.