RESUMO
Small-molecule probes can illuminate biological processes and aid in the assessment of emerging therapeutic targets by perturbing biological systems in a manner distinct from other experimental approaches. Despite the tremendous promise of chemical tools for investigating biology and disease, small-molecule probes were unavailable for most targets and pathways as recently as a decade ago. In 2005, the NIH launched the decade-long Molecular Libraries Program with the intent of innovating in and broadening access to small-molecule science. This Perspective describes how novel small-molecule probes identified through the program are enabling the exploration of biological pathways and therapeutic hypotheses not otherwise testable. These experiences illustrate how small-molecule probes can help bridge the chasm between biological research and the development of medicines but also highlight the need to innovate the science of therapeutic discovery.
Assuntos
Descoberta de Drogas , Bibliotecas de Moléculas Pequenas , Animais , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Ensaios de Triagem em Larga Escala , Humanos , National Institutes of Health (U.S.) , Estados UnidosRESUMO
The ClpB-DnaK bichaperone system reactivates aggregated cellular proteins and is essential for survival of bacteria, fungi, protozoa, and plants under stress. AAA+ ATPase ClpB is a promising target for the development of antimicrobials because a loss of its activity is detrimental for survival of many pathogens and no apparent ClpB orthologs are found in metazoans. We investigated ClpB activity in the presence of several compounds that were previously described as inhibitor leads for the human AAA+ ATPase p97, an antitumor target. We discovered that N2,N4-dibenzylquinazoline-2,4-diamine (DBeQ), the least potent among the tested p97 inhibitors, binds to ClpB with a Kdâ¼60 µM and inhibits the casein-activated, but not the basal, ATPase activity of ClpB with an IC50â¼5 µM. The remaining p97 ligands, which displayed a higher affinity toward p97, did not affect the ClpB ATPase. DBeQ also interacted with DnaK with a Kdâ¼100 µM and did not affect the DnaK ATPase but inhibited the DnaK chaperone activity in vitro. DBeQ inhibited the reactivation of aggregated proteins by the ClpB-DnaK bichaperone system in vitro with an IC50â¼5 µM and suppressed the growth of cultured Escherichia coli. The DBeQ-induced loss of E. coli proliferation was exacerbated by heat shock but was nearly eliminated in a ClpB-deficient E. coli strain, which demonstrates a significant selectivity of DBeQ toward ClpB in cells. Our results provide chemical validation of ClpB as a target for developing novel antimicrobials. We identified DBeQ as a promising lead compound for structural optimization aimed at selective targeting of ClpB and/or DnaK.
Assuntos
Reposicionamento de Medicamentos/métodos , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Escherichia coli/fisiologia , Viabilidade Microbiana , Adenosina Trifosfatases/metabolismo , Western Blotting , Endopeptidase Clp/genética , Endopeptidase Clp/metabolismo , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Polarização de Fluorescência , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Microscopia Confocal , Ressonância de Plasmônio de SuperfícieRESUMO
The suboptimal effectiveness of ß-lactam antibiotics against Mycobacterium tuberculosis has hindered the utility of this compound class for tuberculosis treatment. However, the results of treatment with a second-line regimen containing meropenem plus a ß-lactamase inhibitor were found to be encouraging in a case study of extensively drug-resistant tuberculosis (M. C. Payen, S. De Wit, C. Martin, R. Sergysels, et al., Int J Tuberc Lung Dis 16:558-560, 2012, https://doi.org/10.5588/ijtld.11.0414). We hypothesized that the innate resistance of M. tuberculosis to ß-lactams is mediated in part by noncanonical accessory proteins that are not considered the classic targets of ß-lactams and that small-molecule inhibitors of those accessory targets might sensitize M. tuberculosis to ß-lactams. In this study, we screened an NIH small-molecule library for the ability to sensitize M. tuberculosis to meropenem. We identified six hit compounds, belonging to either the N-arylindole or benzothiophene chemotype. Verification studies confirmed the synthetic lethality phenotype for three of the N-arylindoles and one benzothiophene derivative. The latter was demonstrated to be partially bioavailable via oral administration in mice. Structure-activity relationship studies of both structural classes identified analogs with potent antitubercular activity, alone or in combination with meropenem. Transcriptional profiling revealed that oxidoreductases, MmpL family proteins, and a 27-kDa benzoquinone methyltransferase could be the targets of the N-arylindole potentiator. In conclusion, our compound-compound synthetic lethality screening revealed novel small molecules that were capable of potentiating the action of meropenem, presumably via inhibition of the innate resistance conferred by ß-lactam accessory proteins. ß-Lactam compound-compound synthetic lethality may be an alternative approach for drug-resistant tuberculosis.
Assuntos
Antituberculosos/farmacologia , Mycobacterium tuberculosis/efeitos dos fármacos , Mutações Sintéticas Letais/efeitos dos fármacos , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , beta-Lactamas/farmacologia , Animais , Antibacterianos/farmacologia , Tuberculose Extensivamente Resistente a Medicamentos/tratamento farmacológico , Tuberculose Extensivamente Resistente a Medicamentos/metabolismo , Feminino , Meropeném/farmacologia , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana/métodos , Tuberculose Resistente a Múltiplos Medicamentos/metabolismo , Inibidores de beta-Lactamases/farmacologia , beta-Lactamases/metabolismoRESUMO
UNLABELLED: Among the known genetic risk factors for Parkinson disease, mutations in GBA1, the gene responsible for the lysosomal disorder Gaucher disease, are the most common. This genetic link has directed attention to the role of the lysosome in the pathogenesis of parkinsonism. To study how glucocerebrosidase impacts parkinsonism and to evaluate new therapeutics, we generated induced human pluripotent stem cells from four patients with Type 1 (non-neuronopathic) Gaucher disease, two with and two without parkinsonism, and one patient with Type 2 (acute neuronopathic) Gaucher disease, and differentiated them into macrophages and dopaminergic neurons. These cells exhibited decreased glucocerebrosidase activity and stored the glycolipid substrates glucosylceramide and glucosylsphingosine, demonstrating their similarity to patients with Gaucher disease. Dopaminergic neurons from patients with Type 2 and Type 1 Gaucher disease with parkinsonism had reduced dopamine storage and dopamine transporter reuptake. Levels of α-synuclein, a protein present as aggregates in Parkinson disease and related synucleinopathies, were selectively elevated in neurons from the patients with parkinsonism or Type 2 Gaucher disease. The cells were then treated with NCGC607, a small-molecule noninhibitory chaperone of glucocerebrosidase identified by high-throughput screening and medicinal chemistry structure optimization. This compound successfully chaperoned the mutant enzyme, restored glucocerebrosidase activity and protein levels, and reduced glycolipid storage in both iPSC-derived macrophages and dopaminergic neurons, indicating its potential for treating neuronopathic Gaucher disease. In addition, NCGC607 reduced α-synuclein levels in dopaminergic neurons from the patients with parkinsonism, suggesting that noninhibitory small-molecule chaperones of glucocerebrosidase may prove useful for the treatment of Parkinson disease. SIGNIFICANCE STATEMENT: Because GBA1 mutations are the most common genetic risk factor for Parkinson disease, dopaminergic neurons were generated from iPSC lines derived from patients with Gaucher disease with and without parkinsonism. These cells exhibit deficient enzymatic activity, reduced lysosomal glucocerebrosidase levels, and storage of glucosylceramide and glucosylsphingosine. Lines generated from the patients with parkinsonism demonstrated elevated levels of α-synuclein. To reverse the observed phenotype, the neurons were treated with a novel noninhibitory glucocerebrosidase chaperone, which successfully restored glucocerebrosidase activity and protein levels and reduced glycolipid storage. In addition, the small-molecule chaperone reduced α-synuclein levels in dopaminergic neurons, indicating that chaperoning glucocerebrosidase to the lysosome may provide a novel therapeutic strategy for both Parkinson disease and neuronopathic forms of Gaucher disease.
Assuntos
Neurônios Dopaminérgicos/metabolismo , Doença de Gaucher/patologia , Glucosilceramidas/antagonistas & inibidores , Glicolipídeos/metabolismo , Células-Tronco Pluripotentes Induzidas/efeitos dos fármacos , Transtornos Parkinsonianos/patologia , alfa-Sinucleína/metabolismo , Acetanilidas/farmacologia , Benzamidas/farmacologia , Catecolaminas/metabolismo , Diferenciação Celular/genética , Neurônios Dopaminérgicos/efeitos dos fármacos , Feminino , Glucosilceramidase , Glucosilceramidas/metabolismo , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Potenciais Pós-Sinápticos Inibidores/efeitos dos fármacos , Potenciais Pós-Sinápticos Inibidores/genética , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Masculino , Potenciais da Membrana/efeitos dos fármacos , Potenciais da Membrana/genética , Mutação/genética , Técnicas de Patch-Clamp , beta-Glucosidase/genéticaRESUMO
BACKGROUND: Uropathogenic Escherichia coli (UPEC), a leading cause of urinary tract and invasive infections worldwide, is rapidly acquiring multidrug resistance, hastening the need for selective new anti-infective agents. Here we demonstrate the molecular target of DU011, our previously discovered potent, nontoxic, small-molecule inhibitor of UPEC polysaccharide capsule biogenesis and virulence. METHODS: Real-time polymerase chain reaction analysis and a target-overexpression drug-suppressor screen were used to localize the putative inhibitor target. A thermal shift assay quantified interactions between the target protein and the inhibitor, and a novel DNase protection assay measured chemical inhibition of protein-DNA interactions. Virulence of a regulatory target mutant was assessed in a murine sepsis model. RESULTS: MprA, a MarR family transcriptional repressor, was identified as the putative target of the DU011 inhibitor. Thermal shift measurements indicated the formation of a stable DU011-MprA complex, and DU011 abrogated MprA binding to its DNA promoter site. Knockout of mprA had effects similar to that of DU011 treatment of wild-type bacteria: a loss of encapsulation and complete attenuation in a murine sepsis model, without any negative change in antibiotic resistance. CONCLUSIONS: MprA regulates UPEC polysaccharide encapsulation, is essential for UPEC virulence, and can be targeted without inducing antibiotic resistance.
Assuntos
Antibacterianos/farmacologia , Cápsulas Bacterianas/metabolismo , Descoberta de Drogas/métodos , Proteínas de Escherichia coli/antagonistas & inibidores , Técnicas de Silenciamento de Genes/métodos , Proteínas Repressoras/antagonistas & inibidores , Escherichia coli Uropatogênica/genética , Animais , Antibacterianos/química , Cápsulas Bacterianas/efeitos dos fármacos , Modelos Animais de Doenças , Farmacorresistência Bacteriana Múltipla , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Repressoras/genética , Escherichia coli Uropatogênica/efeitos dos fármacos , VirulênciaRESUMO
Optimization of the sulfonamide-based kappa opioid receptor (KOR) antagonist probe molecule ML140 through constraint of the sulfonamide nitrogen within a tetrahydroisoquinoline moiety afforded a marked increase in potency. This strategy, when combined with additional structure-activity relationship exploration, has led to a compound only six-fold less potent than norBNI, a widely utilized KOR antagonist tool compound, but significantly more synthetically accessible. The new optimized probe is suitably potent for use as an in vivo tool to investigate the therapeutic potential of KOR antagonists.
Assuntos
Benzamidas/farmacologia , Receptores Opioides kappa/antagonistas & inibidores , Relação Estrutura-Atividade , Sulfonamidas/farmacologia , Animais , Arrestinas/metabolismo , Benzamidas/química , Células CHO , Técnicas de Química Sintética , Cricetulus , Avaliação Pré-Clínica de Medicamentos/métodos , Guanosina 5'-O-(3-Tiotrifosfato)/metabolismo , Humanos , Naltrexona/análogos & derivados , Naltrexona/química , Antagonistas de Entorpecentes/química , Antagonistas de Entorpecentes/farmacologia , Receptores Opioides kappa/genética , Sulfonamidas/química , Tetra-Hidroisoquinolinas/química , beta-ArrestinasRESUMO
ATP hydrolysis fuels the ability of helicases and related proteins to translocate on nucleic acids and separate base pairs. As a consequence, nucleic acid binding stimulates the rate at which a helicase catalyzes ATP hydrolysis. In this study, we searched a library of small molecule helicase inhibitors for compounds that stimulate ATP hydrolysis catalyzed by the hepatitis C virus (HCV) NS3 helicase, which is an important antiviral drug target. Two compounds were found that stimulate HCV helicase-catalyzed ATP hydrolysis, both of which are amide derivatives synthesized from the main component of the yellow dye primuline. Both compounds possess a terminal pyridine moiety, which was critical for stimulation. Analogs lacking a terminal pyridine inhibited HCV helicase catalyzed ATP hydrolysis. Unlike other HCV helicase inhibitors, the stimulatory compounds differentiate between helicases isolated from various HCV genotypes and related viruses. The compounds only stimulated ATP hydrolysis catalyzed by NS3 purified from HCV genotype 1b. They inhibited helicases from other HCV genotypes (e.g. 1a and 2a) or related flaviviruses (e.g. Dengue virus). The stimulatory compounds interacted with HCV helicase in the absence of ATP with dissociation constants of about 2 µM. Molecular modeling and site-directed mutagenesis studies suggest that the stimulatory compounds bind in the HCV helicase RNA-binding cleft near key residues Arg-393, Glu-493, and Ser-231.
Assuntos
Trifosfato de Adenosina/química , Hepacivirus/enzimologia , Modelos Moleculares , RNA Helicases/química , RNA Viral , Tiazóis/química , Proteínas Virais/química , Trifosfato de Adenosina/metabolismo , Hepacivirus/genética , Hidrólise , Mutagênese Sítio-Dirigida , RNA Helicases/genética , RNA Helicases/metabolismo , Proteínas Virais/genética , Proteínas Virais/metabolismoRESUMO
Typical assays used to discover and analyze small molecules that inhibit the hepatitis C virus (HCV) NS3 helicase yield few hits and are often confounded by compound interference. Oligonucleotide binding assays are examined here as an alternative. After comparing fluorescence polarization (FP), homogeneous time-resolved fluorescence (HTRF®; Cisbio) and AlphaScreen® (Perkin Elmer) assays, an FP-based assay was chosen to screen Sigma's Library of Pharmacologically Active Compounds (LOPAC) for compounds that inhibit NS3-DNA complex formation. Four LOPAC compounds inhibited the FP-based assay: aurintricarboxylic acid (ATA) (IC50=1.4 µM), suramin sodium salt (IC50=3.6 µM), NF 023 hydrate (IC50=6.2 µM) and tyrphostin AG 538 (IC50=3.6 µM). All but AG 538 inhibited helicase-catalyzed strand separation, and all but NF 023 inhibited replication of subgenomic HCV replicons. A counterscreen using Escherichia coli single-stranded DNA binding protein (SSB) revealed that none of the new HCV helicase inhibitors were specific for NS3h. However, when the SSB-based assay was used to analyze derivatives of another non-specific helicase inhibitor, the main component of the dye primuline, it revealed that some primuline derivatives (e.g. PubChem CID50930730) are up to 30-fold more specific for HCV NS3h than similarly potent HCV helicase inhibitors.
Assuntos
Inibidores Enzimáticos/farmacologia , Hepacivirus/enzimologia , Ensaios de Triagem em Larga Escala , RNA Helicases/antagonistas & inibidores , Proteínas não Estruturais Virais/antagonistas & inibidores , DNA/metabolismo , Proteínas de Ligação a DNA/metabolismo , Ensaios Enzimáticos , Proteínas de Escherichia coli/metabolismo , Polarização de Fluorescência , RNA Helicases/metabolismo , Bibliotecas de Moléculas Pequenas , Proteínas não Estruturais Virais/metabolismoRESUMO
A specific small-molecule inhibitor of p97 would provide an important tool to investigate diverse functions of this essential ATPase associated with diverse cellular activities (AAA) ATPase and to evaluate its potential to be a therapeutic target in human disease. We carried out a high-throughput screen to identify inhibitors of p97 ATPase activity. Dual-reporter cell lines that simultaneously express p97-dependent and p97-independent proteasome substrates were used to stratify inhibitors that emerged from the screen. N2,N4-dibenzylquinazoline-2,4-diamine (DBeQ) was identified as a selective, potent, reversible, and ATP-competitive p97 inhibitor. DBeQ blocks multiple processes that have been shown by RNAi to depend on p97, including degradation of ubiquitin fusion degradation and endoplasmic reticulum-associated degradation pathway reporters, as well as autophagosome maturation. DBeQ also potently inhibits cancer cell growth and is more rapid than a proteasome inhibitor at mobilizing the executioner caspases-3 and -7. Our results provide a rationale for targeting p97 in cancer therapy.
Assuntos
Adenosina Trifosfatases/antagonistas & inibidores , Adenosina Trifosfatases/metabolismo , Autofagia/efeitos dos fármacos , Retículo Endoplasmático/enzimologia , Inibidores Enzimáticos/farmacologia , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/metabolismo , Quinazolinas/farmacologia , Ubiquitina/metabolismo , Adenosina Trifosfatases/genética , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Caspase 3/genética , Caspase 3/metabolismo , Caspase 7/genética , Caspase 7/metabolismo , Linhagem Celular , Retículo Endoplasmático/genética , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Camundongos , Neoplasias/tratamento farmacológico , Neoplasias/enzimologia , Proteínas Nucleares/genética , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Quinazolinas/síntese química , Quinazolinas/química , Ubiquitina/genéticaRESUMO
The discovery and application of a new branching pathway synthesis strategy that rapidly produces skeletally diverse scaffolds is described. Two different scaffold types, one a bicyclic iodo-vinylidene tertiary amine/tertiary alcohol and the other, a spirocyclic 3-furanone, are each obtained using a two-step sequence featuring a common first step. Both scaffold types lead to intermediates that can be orthogonally diversified using the same final components. One of the scaffold types was obtained in sufficiently high yield that it was immediately used to produce a 97-compound library.
Assuntos
Alcinos/química , Compostos Bicíclicos Heterocíclicos com Pontes/química , Propanóis/química , Compostos de Espiro/química , Estrutura Molecular , EstereoisomerismoRESUMO
PURPOSE: 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), one of the most prevalent and procarcinogenic compounds in tobacco, is bioactivated by respiratory cytochrome P450 (CYP) 2A13, forming DNA adducts and initiating lung cancer. CYP2A13 inhibition offers a novel strategy for chemoprevention of tobacco-associated lung cancer. METHODS: Twenty-four analogs of a 4-benzylmorpholine scaffold identified by high throughput screening were evaluated for binding and inhibition of both functional human CYP2A enzymes, CYP2A13 and the 94%-identical hepatic CYP2A6, whose inhibition is undesirable. Thus, selectivity is a major challenge in compound design. RESULTS: A key feature resulting in CYP2A13-selective binding and inhibition was substitution at the benzyl ortho position, with three analogs being >25-fold selective for CYP2A13 over CYP2A6. CONCLUSIONS: Two such analogs were negative for genetic and hERG toxicities and metabolically stable in human lung microsomes, but displayed rapid metabolism in human liver and in mouse and rat lung and liver microsomes, likely due to CYP2B-mediated degradation. A specialized knockout mouse mimicking the human lung demonstrates compound persistence in lung and provides an appropriate test model. Compound delivered by inhalation may be effective in the lung but rapidly cleared otherwise, limiting systemic exposure.
Assuntos
Anticarcinógenos/farmacologia , Hidrocarboneto de Aril Hidroxilases/antagonistas & inibidores , Neoplasias Pulmonares/etiologia , Neoplasias Pulmonares/prevenção & controle , Pulmão/enzimologia , Morfolinas/farmacologia , Fumar/efeitos adversos , Animais , Anticarcinógenos/química , Hidrocarboneto de Aril Hidroxilases/metabolismo , Carcinógenos/metabolismo , Quimioprevenção , Citocromo P-450 CYP2A6 , Humanos , Fígado/efeitos dos fármacos , Fígado/enzimologia , Pulmão/efeitos dos fármacos , Neoplasias Pulmonares/metabolismo , Masculino , Camundongos , Microssomos/efeitos dos fármacos , Microssomos/enzimologia , Microssomos/metabolismo , Morfolinas/química , Nitrosaminas/efeitos adversos , Nitrosaminas/metabolismo , Ratos , Fumar/metabolismo , Nicotiana/metabolismoRESUMO
Substituted pyrimidine inhibitors of the Clk and Dyrk kinases have been developed, exploring structure-activity relationships around four different chemotypes. The most potent compounds have low-nanomolar inhibitory activity against Clk1, Clk2, Clk4, Dyrk1A and Dyrk1B. Kinome scans with 442 kinases using agents representing three of the chemotypes show these inhibitors to be highly selective for the Clk and Dyrk families. Further off-target pharmacological evaluation with ML315, the most selective agent, supports this conclusion.
Assuntos
Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/antagonistas & inibidores , Pirimidinas/química , Pirimidinas/farmacologia , Fosforilação , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Tirosina Quinases/metabolismo , Relação Estrutura-Atividade , Especificidade por Substrato , Quinases DyrkRESUMO
The SR-like splicing factor SFRS10 (Htra2-beta1) is well known to influence various alternatively spliced exons without being an essential splicing factor. We have shown earlier that SFRS10 binds SMN1/SMN2 RNA and restores full-length (FL)-SMN2 mRNA levels in vitro. As SMN1 is absent in patients with spinal muscular atrophy (SMA), the level of FL-SMN2 determines the disease severity. Correct splicing of SMN2 can be facilitated by histone deacetylase inhibitors (HDACis) via upregulation of SFRS10. As HDACis are already used in SMA clinical trials, it is crucial to identify the spectrum of alternatively spliced transcripts modulated by SFRS10, because elevated SFRS10 levels may influence or misregulate also other biological processes. To address this issue, we generated a conditional Sfrs10 allele in mice using the Cre/loxP system. The ubiquitous homozygous deletion of Sfrs10, however, resulted in early embryonic lethality around E7.5, indicating an essential role of Sfrs10 during mouse embryogenesis. Deletion of Sfrs10 with recombinant Cre in murine embryonic fibroblasts (MEFs) derived from Sfrs10(fl/fl) embryos increased the low levels of SmnDelta7 3-4-fold, without affecting FL-Smn levels. The weak influence of Sfrs10 on Smn splicing was further proven by a Hb9-Cre driven motor neuron-specific deletion of Sfrs10 in mice, which developed normally without revealing any SMA phenotype. To assess the role of Sfrs10 on FL-SMN2 splicing, we established MEFs from Smn(-/-);SMN2(tg/tg);Sfrs10(fl/fl) embryos. Surprisingly, deletion of Sfrs10 by recombinant Cre showed no impact on SMN2 splicing but increased SMN levels. Our findings highlight the complexity by which alternatively spliced exons are regulated in vivo.
Assuntos
Processamento Alternativo/genética , Perda do Embrião/genética , Éxons/genética , Proteínas de Ligação a RNA/metabolismo , Proteína 1 de Sobrevivência do Neurônio Motor/metabolismo , Animais , Células Cultivadas , Primers do DNA/genética , Fibroblastos/metabolismo , Deleção de Genes , Genótipo , Imuno-Histoquímica , Integrases , Camundongos , Camundongos Transgênicos , Proteínas Nucleares , Proteínas de Ligação a RNA/genética , Fatores de Processamento de Serina-Arginina , Transdução GenéticaRESUMO
Pancreatic cancer is a devastating disease with a dismal prognosis and poor treatment outcomes. Searching for new agents for pancreatic cancer treatment is of great significance. We previously identified a novel activity of compound C150 to inhibit pancreatic cancer epithelial-to-mesenchymal transition (EMT). Here, we further revealed its mechanism of action. C150 induced ER stress in pancreatic cancer cells and subsequently increased proteasome activity by enhancing proteasome assembly, which subsequently enhanced the degradation of critical EMT transcription factors (EMT-TFs). In addition, as cellular responses to ER stress, autophagy was elevated, and general protein synthesis was inhibited in pancreatic cancer cells. Besides EMT inhibition, the C150-induced ER stress resulted in G2/M cell cycle arrest, which halted cell proliferation and led to cellular senescence. In an orthotopic syngeneic mouse model, an oral dose of C150 at 150 mg/kg 3× weekly significantly increased survival of mice bearing pancreatic tumors, and reduced tumor growth and ascites occurrence. These results suggested that compound C150 holds promises in comprehensively inhibiting pancreatic cancer progression.
RESUMO
Cancers are frequently addicted to oncogenic missense mutant p53 (mutp53). DNAJA1, a member of heat shock protein 40 (HSP40), also known as J-domain proteins (JDPs), plays a crucial role in the stabilization and oncogenic activity of misfolded or conformational mutp53 by binding to and preventing mutp53 from proteasomal degradation. However, strategies to deplete mutp53 are not well-established, and no HSP40/JDPs inhibitors are clinically available. To identify compounds that bind to DNAJA1 and induce mutp53 degradation, we performed an in silico docking study of ~10 million of compounds from the ZINC database for the J-domain of DNAJA1. A compound 7-3 was identified, and its analogue A11 effectively reduced the levels of DNAJA1 and conformational mutp53 with minimal effects on the levels of wild-type p53 and DNA-contact mutp53. A11 suppressed migration and filopodia formation in a manner dependent on DNAJA1 and conformational mutp53. A mutant DNAJA1 with alanine mutations at predicted amino acids (tyrosine 7, lysine 44, and glutamine 47) failed to bind to A11. Cells expressing the mutant DNAJA1 became insensitive to A11-mediated depletion of DNAJA1 and mutp53 as well as A11-mediated inhibition of cell migration. Thus, A11 is the first HSP40/JDP inhibitor that has not been previously characterized for depleting DNAJA1 and subsequently conformational mutp53, leading to inhibition of cancer cell migration. A11 can be exploited for a novel treatment against cancers expressing conformational mutp53.
RESUMO
The perinucleolar compartment (PNC) is a dynamic subnuclear body found at the periphery of the nucleolus. The PNC is enriched with RNA transcripts and RNA-binding proteins, reflecting different states of genome organization. PNC prevalence positively correlates with cancer progression and metastatic capacity, making it a useful marker for metastatic cancer progression. A high-throughput, high-content assay was developed to identify novel small molecules that selectively reduce PNC prevalence in cancer cells. We identified and further optimized a pyrrolopyrimidine series able to reduce PNC prevalence in PC3M cancer cells at submicromolar concentrations without affecting cell viability. Structure-activity relationship exploration of the structural elements necessary for activity resulted in the discovery of several potent compounds. Analysis of in vitro drug-like properties led to the discovery of the bioavailable analogue, metarrestin, which has shown potent antimetastatic activity with improved survival in rodent models and is currently being evaluated in a first-in-human phase 1 clinical trial.
Assuntos
Núcleo Celular , Neoplasias , Biomarcadores/metabolismo , Nucléolo Celular/metabolismo , Nucléolo Celular/patologia , Núcleo Celular/metabolismo , Humanos , Neoplasias/metabolismo , Pirimidinas , PirróisRESUMO
Pancreatic cancer cell epithelial-to-mesenchymal transition (EMT) is an important contributor to cell invasion and tumor progression. Therefore, targeting EMT may be beneficial for pancreatic cancer treatment. The aim of the present study was to report on the inhibitory effect of the novel compound C150 on the EMT of pancreatic cancer cells. C150 inhibited cell proliferation in multiple pancreatic cancer cells with IC50 values of 1-2.5 µM, while in an non-cancerous pancreatic epithelial cell line hTERT-HPNE the IC50 value was >12.5 µM. C150 significantly inhibited pancreatic cancer cell migration and invasion, as demonstrated by 3-dimensional cell invasion, wound healing and Boyden chamber Transwell migration-invasion assays. Moreover, C150 treatment decreased MMP-2 gene expression in PANC-1 cells and reduced MMP-2 activity in gelatin zymography assay. In an orthotopic mouse model of pancreatic cancer, C150 significantly reduced tumor growth at the dose of 15 mg/kg by intraperitoneal injection three times per week. Furthermore, C150 enhanced protein degradation of Snail, an important EMT-promoting transcription factor, and decreased the expression of the mesenchymal marker N-cadherin, while it increased the expression of the epithelial markers zonula occludens-1 and claudin-1. The findings of the present study suggested that C150 is a novel EMT inhibitor that may be promising for inhibiting pancreatic cancer growth and metastasis.
RESUMO
As ß-lactams are reconsidered for the treatment of tuberculosis (TB), their targets are assumed to be peptidoglycan transpeptidases, as verified by adduct formation and kinetic inhibition of Mycobacterium tuberculosis (Mtb) transpeptidases by carbapenems active against replicating Mtb. Here, we investigated the targets of recently described cephalosporins that are selectively active against non-replicating (NR) Mtb. NR-active cephalosporins failed to inhibit recombinant Mtb transpeptidases. Accordingly, we used alkyne analogs of NR-active cephalosporins to pull down potential targets through unbiased activity-based protein profiling and identified over 30 protein binders. None was a transpeptidase. Several of the target candidates are plausibly related to Mtb's survival in an NR state. However, biochemical tests and studies of loss of function mutants did not identify a unique target that accounts for the bactericidal activity of these beta-lactams against NR Mtb. Instead, NR-active cephalosporins appear to kill Mtb by collective action on multiple targets. These results highlight the ability of these ß-lactams to target diverse classes of proteins.
RESUMO
A sequential three-component synthesis of functionalized benzisothiazoline-3-acetic acid 1,1-dioxides utilizing a domino Heck-aza-Michael pathway is reported. This one-pot procedure rapidly assembles functionalized benzylsulfonamides, which undergo a palladium-catalyzed, domino, Heck-aza-Michael transformation in an experimentally straightforward manner. This attractive protocol has been utilized to synthesize three combinatorial sublibraries (I-III) comprising a total of 95 compounds in high purities (> or =95% for 75 compounds), yield and quantities.
Assuntos
Acetatos/síntese química , Técnicas de Química Combinatória/métodos , Óxidos/síntese química , Bibliotecas de Moléculas Pequenas/síntese química , Tiazóis/química , Acetatos/química , Técnicas de Química Combinatória/economia , Óxidos/química , Bibliotecas de Moléculas Pequenas/química , Tiazóis/síntese químicaRESUMO
p97 is an ATPase that works in concert with histone deacetylase 6 (HDAC6), to facilitate the degradation of misfolded proteins by autophagosomes. p97 has also been implicated in DNA repair and maintaining genomic stability. In this study, we determined the effect of combined inhibition of p97 and HDAC6 activities in mantle cell lymphoma (MCL) cells. We report that treatment with p97 inhibitors induces dose-dependent apoptosis in MCL cells. The p97 inhibitor CB-5083 induces ER stress markers GRP78 and CHOP and results in the accumulation of polyubiquitylated proteins. Co-treatment with CB-5083 and the HDAC6 inhibitor ACY-1215 result in marked downregulation of CDK4, Cyclin D1, and BRCA1 levels without inhibiting autophagic flux. Consequently, treatment with CB-5083 accentuates DNA damage in response to treatment with ACY-1215 resulting in enhanced accumulation of H2AX-γ and synergistic apoptosis. Furthermore, ATM loss severely impairs phosphorylation of 53BP1 following co-treatment with CB-5083 and ACY-1215 in response to gamma irradiation. Finally, co-treatment CB-5083 and ACY-1215 results in reduced tumor volumes and improves survival in Z138C and Jeko-1 xenografts in NSG mice. These observations suggest that combined inhibition of p97 and HDAC6 abrogates resolution of proteotoxic stress and impairs DNA repair mechanisms in MCL cells.