RESUMO
Human ribonucleotide reductase (hRR) is crucial for DNA replication and maintenance of a balanced dNTP pool, and is an established cancer target. Nucleoside analogs such as gemcitabine diphosphate and clofarabine nucleotides target the large subunit (hRRM1) of hRR. These drugs have a poor therapeutic index due to toxicity caused by additional effects, including DNA chain termination. The discovery of nonnucleoside, reversible, small-molecule inhibitors with greater specificity against hRRM1 is a key step in the development of more effective treatments for cancer. Here, we report the identification and characterization of a unique nonnucleoside small-molecule hRR inhibitor, naphthyl salicylic acyl hydrazone (NSAH), using virtual screening, binding affinity, inhibition, and cell toxicity assays. NSAH binds to hRRM1 with an apparent dissociation constant of 37 µM, and steady-state kinetics reveal a competitive mode of inhibition. A 2.66-Å resolution crystal structure of NSAH in complex with hRRM1 demonstrates that NSAH functions by binding at the catalytic site (C-site) where it makes both common and unique contacts with the enzyme compared with NDP substrates. Importantly, the IC50 for NSAH is within twofold of gemcitabine for growth inhibition of multiple cancer cell lines, while demonstrating little cytotoxicity against normal mobilized peripheral blood progenitor cells. NSAH depresses dGTP and dATP levels in the dNTP pool causing S-phase arrest, providing evidence for RR inhibition in cells. This report of a nonnucleoside reversible inhibitor binding at the catalytic site of hRRM1 provides a starting point for the design of a unique class of hRR inhibitors.
Assuntos
Hidrazonas/farmacologia , Naftalenos/farmacologia , Ribonucleotídeo Redutases/antagonistas & inibidores , Salicilatos/farmacologia , Domínio Catalítico , Ciclo Celular/efeitos dos fármacos , Cristalografia por Raios X , Nucleotídeos de Desoxiadenina/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Humanos , Hidrazonas/química , Naftalenos/química , Ribonucleosídeo Difosfato Redutase , Ribonucleotídeo Redutases/química , Ribonucleotídeo Redutases/metabolismo , Salicilatos/química , Proteínas Supressoras de Tumor/antagonistas & inibidores , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/metabolismoRESUMO
Usher syndrome type III (USH3), characterized by progressive deafness, variable balance disorder and blindness, is caused by destabilizing mutations in the gene encoding the clarin-1 (CLRN1) protein. Here we report a new strategy to mitigate hearing loss associated with a common USH3 mutation CLRN1(N48K) that involves cell-based high-throughput screening of small molecules capable of stabilizing CLRN1(N48K), followed by a secondary screening to eliminate general proteasome inhibitors, and finally an iterative process to optimize structure-activity relationships. This resulted in the identification of BioFocus 844 (BF844). To test the efficacy of BF844, we developed a mouse model that mimicked the progressive hearing loss associated with USH3. BF844 effectively attenuated progressive hearing loss and prevented deafness in this model. Because the CLRN1(N48K) mutation causes both hearing and vision loss, BF844 could in principle prevent both sensory deficiencies in patients with USH3. Moreover, the strategy described here could help identify drugs for other protein-destabilizing monogenic disorders.
Assuntos
Modelos Animais de Doenças , Proteínas de Membrana/antagonistas & inibidores , Pirazóis/farmacologia , Piridazinas/farmacologia , Bibliotecas de Moléculas Pequenas/química , Bibliotecas de Moléculas Pequenas/uso terapêutico , Síndromes de Usher/tratamento farmacológico , Animais , Ensaios de Triagem em Larga Escala , Humanos , Proteínas de Membrana/deficiência , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Estrutura Molecular , Pirazóis/síntese química , Pirazóis/química , Pirazóis/uso terapêutico , Piridazinas/síntese química , Piridazinas/química , Piridazinas/uso terapêutico , Bibliotecas de Moléculas Pequenas/síntese química , Bibliotecas de Moléculas Pequenas/farmacologia , Relação Estrutura-Atividade , Síndromes de Usher/genéticaRESUMO
Vertebrate vision is initiated by photoisomerization of the visual pigment chromophore 11-cis-retinal and is maintained by continuous regeneration of this retinoid through a series of reactions termed the retinoid cycle. However, toxic side reaction products, especially those involving reactive aldehyde groups of the photoisomerized product, all-trans-retinal, can cause severe retinal pathology. Here we lowered peak concentrations of free all-trans-retinal with primary amine-containing Food and Drug Administration (FDA)-approved drugs that did not inhibit chromophore regeneration in mouse models of retinal degeneration. Schiff base adducts between all-trans-retinal and these amines were identified by MS. Adducts were observed in mouse eyes only when an experimental drug protected the retina from degeneration in both short-term and long-term treatment experiments. This study demonstrates a molecular basis of all-trans-retinal-induced retinal pathology and identifies an assemblage of FDA-approved compounds with protective effects against this pathology in a mouse model that shows features of Stargardt's disease and age-related retinal degeneration.
Assuntos
Aminas/uso terapêutico , Degeneração Retiniana/prevenção & controle , Aminas/farmacologia , Animais , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Degeneração Macular/tratamento farmacológico , Camundongos , Degeneração Retiniana/tratamento farmacológico , Retinaldeído/uso terapêutico , Bases de Schiff/análise , Estados Unidos , United States Food and Drug AdministrationRESUMO
Academic discovery in biomedicine is a growing enterprise with tens of billions of dollars in research funding available to universities and hospitals. Protecting and optimizing the resultant intellectual property is required in order for the discoveries to have an impact on society. To achieve that, institutions must create a multidisciplinary, collaborative system of review and support, and utilize connections to industry partners. In this study, we outline the efforts of Case Western Reserve University, coordinated through its Clinical and Translational Science Collaborative (CTSC), to promote entrepreneurial culture, and achieve goals of product development and startup formation for biomedical and population health discoveries arising from the academic ecosystem in Cleveland. The CTSC Office of Translation and Innovation, with the university's Technology Transfer Office (TTO), helps identify and derisk promising IP while building interdisciplinary project teams to optimize the assets through key preclinical derisking steps. The benefits of coordinating funding across multiple programs, assuring dedicated project management to oversee optimizing the IP, and ensuring training to help improve proposals and encourage an entrepreneurial culture, are discussed in the context of a case study of therapeutic assets, the Council to Advance Human Health. This case study highlights best practices in academic innovation.
RESUMO
Small-molecule antivirulence agents represent a promising alternative or adjuvant to antibiotics. These compounds disarm pathogens of disease-causing toxins without killing them, thereby diminishing survival pressure to develop resistance. Here we show that the small-molecule antivirulence agents F12 and F19 block staphylococcal transcription factor AgrA from binding to its promoter. Consequently, toxin expression is inhibited, thus preventing host cell damage by Gram-positive pathogens. Broad spectrum efficacy against Gram-positive pathogens is due to the existence of AgrA homologs in many Gram-positive bacteria. F12 is more efficacious in vitro and F19 works better in vivo. In a murine MRSA bacteremia/sepsis model, F19 treatment alone resulted in 100% survival while untreated animals had 70% mortality. Furthermore, F19 enhances antibiotic efficacy in vivo. Notably, in a murine MRSA wound infection model, combination of F19 with antibiotics resulted in bacterial load reduction. Thus, F19 could be used alone or in combination with antibiotics to prevent and treat infections of Gram-positive pathogens.
Assuntos
Antibacterianos/farmacologia , Proteínas de Bactérias/antagonistas & inibidores , Bactérias Gram-Positivas/efeitos dos fármacos , Infecções Estafilocócicas/tratamento farmacológico , Transativadores/antagonistas & inibidores , Fatores de Virulência/antagonistas & inibidores , Animais , Antibacterianos/administração & dosagem , Modelos Animais de Doenças , Sinergismo Farmacológico , Camundongos , Sepse/tratamento farmacológico , Análise de Sobrevida , Resultado do Tratamento , Virulência/efeitos dos fármacos , Infecção dos Ferimentos/tratamento farmacológicoRESUMO
Rhodopsin homeostasis is tightly coupled to rod photoreceptor cell survival and vision. Mutations resulting in the misfolding of rhodopsin can lead to autosomal dominant retinitis pigmentosa (adRP), a progressive retinal degeneration that currently is untreatable. Using a cell-based high-throughput screen (HTS) to identify small molecules that can stabilize the P23H-opsin mutant, which causes most cases of adRP, we identified a novel pharmacological chaperone of rod photoreceptor opsin, YC-001. As a non-retinoid molecule, YC-001 demonstrates micromolar potency and efficacy greater than 9-cis-retinal with lower cytotoxicity. YC-001 binds to bovine rod opsin with an EC50 similar to 9-cis-retinal. The chaperone activity of YC-001 is evidenced by its ability to rescue the transport of multiple rod opsin mutants in mammalian cells. YC-001 is also an inverse agonist that non-competitively antagonizes rod opsin signaling. Significantly, a single dose of YC-001 protects Abca4 -/- Rdh8 -/- mice from bright light-induced retinal degeneration, suggesting its broad therapeutic potential.
Assuntos
Fármacos Neuroprotetores/farmacologia , Dobramento de Proteína/efeitos dos fármacos , Degeneração Retiniana/tratamento farmacológico , Células Fotorreceptoras Retinianas Bastonetes/efeitos dos fármacos , Rodopsina/metabolismo , Tiofenos/farmacologia , Transportadores de Cassetes de Ligação de ATP/genética , Oxirredutases do Álcool/genética , Animais , Linhagem Celular Tumoral , Modelos Animais de Doenças , Diterpenos , Feminino , Células HEK293 , Ensaios de Triagem em Larga Escala , Humanos , Luz/efeitos adversos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mutação , Células NIH 3T3 , Fármacos Neuroprotetores/uso terapêutico , Transporte Proteico/efeitos dos fármacos , Transporte Proteico/genética , Degeneração Retiniana/etiologia , Degeneração Retiniana/patologia , Células Fotorreceptoras Retinianas Bastonetes/metabolismo , Células Fotorreceptoras Retinianas Bastonetes/patologia , Células Fotorreceptoras Retinianas Bastonetes/efeitos da radiação , Retinaldeído/farmacologia , Retinaldeído/uso terapêutico , Rodopsina/agonistas , Rodopsina/antagonistas & inibidores , Rodopsina/genética , Tiofenos/uso terapêutico , Resultado do TratamentoRESUMO
The Amgen's Data Access Analysis Prediction Tools (ADAAPT) system is a desktop decision support tool developed to provide flexible access and analysis of chemical and biological data. The system is platform independent, adaptable, easily deployed, and scalable. It consists of four main modules: access, analysis, prediction, and tools. The access module contains numerous user interfaces designed to retrieve data easily. The analysis module provides standard computational tools to perform property calculation, QSAR/QSPR, and statistical analyses. The prediction module contains in-house models to calculate a drug-likeness score and absorption index. Finally, the tools module provides a wide array of features that are of general interest to our scientists.
Assuntos
Sistemas Computacionais , Técnicas de Apoio para a Decisão , Desenho de Fármacos , Interpretação Estatística de Dados , Bases de Dados Factuais , Relação Quantitativa Estrutura-Atividade , SoftwareRESUMO
The multistep syntheses of several bicyclic triamines are described, all of which have an imbedded 1,5,9-triazacyclododecane ring. In 1,5,9-triazabicyclo[7.3.3]pentadecanes 12, 13, 15, and 16, two nitrogens are bridged by three carbons. The monoprotonated forms of these triamines are highly stabilized by a hydrogen-bonded network involving the bridge and both bridgehead nitrogens, producing a difference of more than 8 pK(a) units in acidities of their monoprotonated and diprotonated forms. The one- and zero-carbon bridges in 1,5,9-triazabicyclo[9.1.1]tridecane (23) and 7-methyl-1,5,9-triazabicyclo[5.5.0]dodecane (39) do not enhance the stabilities of their monoprotonated forms. X-ray crystal structures and computational studies of 12.HI and 16.HI reveal similar, but somewhat weaker, hydrogen-bonded networks, relative to 15.HI. The activation free energies for conformational inversion of 13.HI (14.4 +/- 0.2 kcal/mol), 16.HI (15.0 +/- 0.1 kcal/mol) and 16 (8.8 +/- 0.3 kcal/mol) were measured by variable-temperature (1)H and (13)C NMR spectroscopy. These experimental barriers give an estimate of 6.2 kcal/mol for the strength of the bifurcated hydrogen bond between the bridge nitrogen and cavity proton in 16.HI. Computational studies support the hypothesis that N-inversion occurs in an open conformation, leading to an estimate of 10.32 kcal/mol for the enthalpy of the bifurcated hydrogen bond in 16.HI in the gas phase.