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Eleven-nineteen leukemia (ENL) is an epigenetic reader protein that drives oncogenic transcriptional programs in acute myeloid leukemia (AML). AML is one of the deadliest hematopoietic malignancies, with an overall 5-year survival rate of 27%. The epigenetic reader activity of ENL is mediated by its YEATS domain that binds to acetyl and crotonyl marks on histone tails and colocalizes with promoters of actively transcribed genes that are essential for leukemia. Prior to the discovery of TDI-11055, existing inhibitors of ENL YEATS showed in vitro potency, but had not shown efficacy in in vivo animal models. During the course of the medicinal chemistry campaign described here, we identified ENL YEATS inhibitor TDI-11055 that has an improved pharmacokinetic profile and is appropriate for in vivo evaluation of the ENL YEATS inhibition mechanism in AML.
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Stimulator of interferon genes (STING) agonists are promising candidates for vaccine adjuvants and antitumor immune stimulants. The most potent natural agonist of STING, 2',3'-cyclic GMP-AMP (2',3'-cGAMP), is subject to nuclease-mediated inherent metabolic instability, thereby placing limits on its clinical efficacy. Here, we report on a new class of chemically synthesized sugar-modified analogs of 2',3'-cGAMP containing arabinose and xylose sugar derivatives that bind mouse and human STING alleles with high affinity. The co-crystal structures demonstrate that such analogs act as 2',3'-cGAMP mimetics that induce the "closed" conformation of human STING. These analogs show significant resistance to hydrolysis mediated by ENPP1 and increased stability in human serum, while retaining similar potency as 2',3'-cGAMP at inducing IFN-ß secretion from human THP1 cells. The arabinose- and xylose-modified 2',3'-cGAMP analogs open a new strategy for overcoming the inherent nuclease-mediated vulnerability of natural ribose cyclic nucleotides, with the additional benefit of high translational potential as cancer therapeutics and vaccine adjuvants.
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Arabinose , Xilose , Humanos , Animais , Camundongos , Arabinose/farmacologia , Adjuvantes de Vacinas , Nucleotídeos Cíclicos/metabolismoRESUMO
OBJECTIVE: Thioesterase superfamily member 1 (Them1) is a long chain acyl-CoA thioesterase comprising two N-terminal HotDog fold enzymatic domains linked to a C-terminal lipid-sensing steroidogenic acute regulatory transfer-related (START) domain, which allosterically modulates enzymatic activity. Them1 is highly expressed in thermogenic adipose tissue, where it functions to suppress energy expenditure by limiting rates of fatty acid oxidation, and is induced markedly in liver in response to high fat feeding, where it suppresses fatty acid oxidation and promotes glucose production. Them1-/- mice are protected against non-alcoholic fatty liver disease (NAFLD), suggesting Them1 as a therapeutic target. METHODS: A high-throughput small molecule screen was performed to identify promising inhibitors targeting the fatty acyl-CoA thioesterase activity of purified recombinant Them1.Counter screening was used to determine specificity for Them1 relative to other acyl-CoA thioesterase isoforms. Inhibitor binding and enzyme inhibition were quantified by biophysical and biochemical approaches, respectively. Following structure-based optimization, lead compounds were tested in cell culture. RESULTS: Two lead allosteric inhibitors were identified that selectively inhibited Them1 by binding the START domain. In mouse brown adipocytes, these inhibitors promoted fatty acid oxidation, as evidenced by increased oxygen consumption rates. In mouse hepatocytes, they promoted fatty acid oxidation, but also reduced glucose production. CONCLUSION: Them1 inhibitors could prove attractive for the pharmacologic management of NAFLD.
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Hepatopatia Gordurosa não Alcoólica , Camundongos , Animais , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Ensaios de Triagem em Larga Escala , Glucose/metabolismo , Ácidos Graxos/metabolismoRESUMO
DnaK is the bacterial homolog of Hsp70, an ATP-dependent chaperone that helps cofactor proteins to catalyze nascent protein folding and salvage misfolded proteins. In the pathogen Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), DnaK and its cofactors are proposed antimycobacterial targets, yet few small-molecule inhibitors or probes exist for these families of proteins. Here, we describe the repurposing of a drug called telaprevir that is able to allosterically inhibit the ATPase activity of DnaK and to prevent chaperone function by mimicking peptide substrates. In mycobacterial cells, telaprevir disrupts DnaK- and cofactor-mediated cellular proteostasis, resulting in enhanced efficacy of aminoglycoside antibiotics and reduced resistance to the frontline TB drug rifampin. Hence, this work contributes to a small but growing collection of protein chaperone inhibitors, and it demonstrates that these molecules disrupt bacterial mechanisms of survival in the presence of different antibiotic classes.
Assuntos
Proteínas de Escherichia coli , Mycobacterium tuberculosis , Tuberculose , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Proteínas de Escherichia coli/metabolismo , Proteínas de Choque Térmico HSP70/metabolismo , Humanos , Chaperonas Moleculares/metabolismo , Mycobacterium tuberculosis/metabolismo , Dobramento de ProteínaRESUMO
Sensing and response to environmental cues, such as pH and chloride (Cl-), is critical in enabling Mycobacterium tuberculosis (Mtb) colonization of its host. Utilizing a fluorescent reporter Mtb strain in a chemical screen, we have identified compounds that dysregulate Mtb response to high Cl- levels, with a subset of the hits also inhibiting Mtb growth in host macrophages. Structure-activity relationship studies on the hit compound "C6," or 2-(4-((2-(ethylthio)pyrimidin-5-yl)methyl)piperazin-1-yl)benzo[d]oxazole, demonstrated a correlation between compound perturbation of Mtb Cl- response and inhibition of bacterial growth in macrophages. C6 accumulated in both bacterial and host cells, and inhibited Mtb growth in cholesterol media, but not in rich media. Subsequent examination of the Cl- response of Mtb revealed an intriguing link with bacterial growth in cholesterol, with increased transcription of several Cl--responsive genes in the simultaneous presence of cholesterol and high external Cl- concentration, versus transcript levels observed during exposure to high external Cl- concentration alone. Strikingly, oral administration of C6 was able to inhibit Mtb growth in vivo in a C3HeB/FeJ murine infection model. Our work illustrates how Mtb response to environmental cues can intersect with its metabolism and be exploited in antitubercular drug discovery.
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Antituberculosos/farmacologia , Desenvolvimento de Medicamentos , Mycobacterium tuberculosis/efeitos dos fármacos , Animais , Antituberculosos/química , Cloretos/metabolismo , Colesterol/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Macrófagos/microbiologia , Camundongos , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/crescimento & desenvolvimento , Relação Estrutura-AtividadeRESUMO
To repurpose therapeutics for fibrolamellar carcinoma (FLC), we developed and validated patient-derived xenografts (PDX) from surgical resections. Most agents used clinically and inhibitors of oncogenes overexpressed in FLC showed little efficacy on PDX. A high-throughput functional drug screen found primary and metastatic FLC were vulnerable to clinically available inhibitors of TOPO1 and HDAC and to napabucasin. Napabucasin's efficacy was mediated through reactive oxygen species and inhibition of translation initiation, and specific inhibition of eIF4A was effective. The sensitivity of each PDX line inversely correlated with expression of the antiapoptotic protein Bcl-xL, and inhibition of Bcl-xL synergized with other drugs. Screening directly on cells dissociated from patient resections validated these results. This demonstrates that a direct functional screen on patient tumors provides therapeutically informative data within a clinically useful time frame. Identifying these novel therapeutic targets and combination therapies is an urgent need, as effective therapeutics for FLC are currently unavailable. SIGNIFICANCE: Therapeutics informed by genomics have not yielded effective therapies for FLC. A functional screen identified TOPO1, HDAC inhibitors, and napabucasin as efficacious and synergistic with inhibition of Bcl-xL. Validation on cells dissociated directly from patient tumors demonstrates the ability for functional precision medicine in a solid tumor.This article is highlighted in the In This Issue feature, p. 2355.
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Carcinoma Hepatocelular/tratamento farmacológico , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/tratamento farmacológico , Ensaios Antitumorais Modelo de Xenoenxerto , Compostos de Anilina/uso terapêutico , Animais , Antineoplásicos/uso terapêutico , Benzofuranos/uso terapêutico , Carcinoma Hepatocelular/genética , Feminino , Humanos , Neoplasias Hepáticas/genética , Masculino , Camundongos , Naftoquinonas/uso terapêutico , Sulfonamidas/uso terapêuticoRESUMO
The MUSASHI (MSI) family of RNA binding proteins (MSI1 and MSI2) contribute to a wide spectrum of cancers including acute myeloid leukemia. We find that the small molecule Ro 08-2750 (Ro) binds directly and selectively to MSI2 and competes for its RNA binding in biochemical assays. Ro treatment in mouse and human myeloid leukemia cells results in an increase in differentiation and apoptosis, inhibition of known MSI-targets, and a shared global gene expression signature similar to shRNA depletion of MSI2. Ro demonstrates in vivo inhibition of c-MYC and reduces disease burden in a murine AML leukemia model. Thus, we identify a small molecule that targets MSI's oncogenic activity. Our study provides a framework for targeting RNA binding proteins in cancer.
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Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Leucemia Experimental/tratamento farmacológico , Leucemia Mieloide Aguda/tratamento farmacológico , Pteridinas/farmacologia , Proteínas de Ligação a RNA/antagonistas & inibidores , Animais , Apoptose/efeitos dos fármacos , Flavinas , Perfilação da Expressão Gênica , Humanos , Leucemia Experimental/sangue , Leucemia Mieloide Aguda/sangue , Masculino , Camundongos , Cultura Primária de Células , Proteínas Proto-Oncogênicas c-myc/metabolismo , Pteridinas/uso terapêutico , RNA/metabolismo , Motivo de Reconhecimento de RNA/efeitos dos fármacos , RNA Interferente Pequeno/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Transcriptoma/efeitos dos fármacos , Células Tumorais CultivadasRESUMO
The cyclic GMP-AMP synthase (cGAS)-cGAMP-STING pathway plays a key role in innate immunity, with cGAS sensing both pathogenic and mislocalized DNA in the cytoplasm. Human cGAS (h-cGAS) constitutes an important drug target for control of antiinflammatory responses that can contribute to the onset of autoimmune diseases. Recent studies have established that the positively charged N-terminal segment of cGAS contributes to enhancement of cGAS enzymatic activity as a result of DNA-induced liquid-phase condensation. We have identified an additional cGASCD-DNA interface (labeled site-C; CD, catalytic domain) in the crystal structure of a human SRY.cGASCD-DNA complex, with mutations along this basic site-C cGAS interface disrupting liquid-phase condensation, as monitored by cGAMP formation, gel shift, spin-down, and turbidity assays, as well as time-lapse imaging of liquid droplet formation. We expand on an earlier ladder model of cGAS dimers bound to a pair of parallel-aligned DNAs to propose a multivalent interaction-mediated cluster model to account for DNA-mediated condensation involving both the N-terminal domain of cGAS and the site-C cGAS-DNA interface. We also report the crystal structure of the h-cGASCD-DNA complex containing a triple mutant that disrupts the site-C interface, with this complex serving as a future platform for guiding cGAS inhibitor development at the DNA-bound h-cGAS level. Finally, we solved the structure of RU.521 bound in two alternate alignments to apo h-cGASCD, thereby occupying more of the catalytic pocket and providing insights into further optimization of active-site-binding inhibitors.
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Domínio Catalítico/fisiologia , DNA/metabolismo , Nucleotidiltransferases/metabolismo , Sequência de Aminoácidos , Humanos , Imunidade Inata/fisiologia , Proteínas de Membrana/metabolismo , Nucleotídeos Cíclicos/metabolismo , Alinhamento de Sequência , Transdução de Sinais/fisiologiaRESUMO
Cyclic GMP-AMP synthase (cGAS) is the primary sensor for aberrant intracellular dsDNA producing the cyclic dinucleotide cGAMP, a second messenger initiating cytokine production in subsets of myeloid lineage cell types. Therefore, inhibition of the enzyme cGAS may act anti-inflammatory. Here we report the discovery of human-cGAS-specific small-molecule inhibitors by high-throughput screening and the targeted medicinal chemistry optimization for two molecular scaffolds. Lead compounds from one scaffold co-crystallize with human cGAS and occupy the ATP- and GTP-binding active site. The specificity and potency of these drug candidates is further documented in human myeloid cells including primary macrophages. These novel cGAS inhibitors with cell-based activity will serve as probes into cGAS-dependent innate immune pathways and warrant future pharmacological studies for treatment of cGAS-dependent inflammatory diseases.
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Descoberta de Drogas/métodos , Inibidores Enzimáticos/farmacologia , Nucleotidiltransferases/antagonistas & inibidores , Doenças Autoimunes/tratamento farmacológico , Doenças Autoimunes/imunologia , Doenças Autoimunes/patologia , Células Cultivadas , Cristalografia por Raios X , DNA/imunologia , DNA/metabolismo , Inibidores Enzimáticos/química , Inibidores Enzimáticos/uso terapêutico , Ensaios de Triagem em Larga Escala/métodos , Humanos , Imunidade Inata/efeitos dos fármacos , Interferons/imunologia , Interferons/metabolismo , Macrófagos , Modelos Moleculares , Nucleotídeos Cíclicos/imunologia , Nucleotídeos Cíclicos/metabolismo , Nucleotidiltransferases/imunologia , Nucleotidiltransferases/isolamento & purificação , Nucleotidiltransferases/metabolismo , Cultura Primária de Células , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismoRESUMO
Disorders of bone healing and remodeling are indications with an unmet need for effective pharmacological modulators. We used a high-throughput screen to identify activators of the bone marker alkaline phosphatase (ALP), and discovered 6,8-dimethyl-3-(4-phenyl-1H-imidazol-5-yl)quinolin-2(1H)-one (DIPQUO). DIPQUO markedly promotes osteoblast differentiation, including expression of Runx2, Osterix, and Osteocalcin. Treatment of human mesenchymal stem cells with DIPQUO results in osteogenic differentiation including a significant increase in calcium matrix deposition. DIPQUO stimulates ossification of emerging vertebral primordia in developing zebrafish larvae, and increases caudal fin osteogenic differentiation during adult zebrafish fin regeneration. The stimulatory effect of DIPQUO on osteoblast differentiation and maturation was shown to be dependent on the p38 MAPK pathway. Inhibition of p38 MAPK signaling or specific knockdown of the p38-ß isoform attenuates DIPQUO induction of ALP, suggesting that DIPQUO mediates osteogenesis through activation of p38-ß, and is a promising lead candidate for development of bone therapeutics.
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Diferenciação Celular/fisiologia , Proteína Quinase 11 Ativada por Mitógeno/metabolismo , Osteoblastos/metabolismo , Fosfatase Alcalina/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Subunidade alfa 1 de Fator de Ligação ao Core , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Camundongos , Proteína Quinase 11 Ativada por Mitógeno/fisiologia , Osteoblastos/fisiologia , Osteogênese , Células RAW 264.7 , Transdução de Sinais/efeitos dos fármacos , Peixe-Zebra , Proteínas Quinases p38 Ativadas por MitógenoRESUMO
Female Aedes aegypti mosquitoes bite humans to obtain blood to develop their eggs. Remarkably, their strong attraction to humans is suppressed for days after the blood meal by an unknown mechanism. We investigated a role for neuropeptide Y (NPY)-related signaling in long-term behavioral suppression and discovered that drugs targeting human NPY receptors modulate mosquito host-seeking. In a screen of all 49 predicted Ae. aegypti peptide receptors, we identified NPY-like receptor 7 (NPYLR7) as the sole target of these drugs. To obtain small-molecule agonists selective for NPYLR7, we performed a high-throughput cell-based assay of 265,211 compounds and isolated six highly selective NPYLR7 agonists that inhibit mosquito attraction to humans. NPYLR7 CRISPR-Cas9 null mutants are defective in behavioral suppression and resistant to these drugs. Finally, we show that these drugs can inhibit biting and blood-feeding on a live host, suggesting a novel approach to control infectious disease transmission by controlling mosquito behavior. VIDEO ABSTRACT.
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Comportamento de Busca por Hospedeiro/efeitos dos fármacos , Mosquitos Vetores/efeitos dos fármacos , Receptores de Neuropeptídeo Y/agonistas , Aedes/metabolismo , Animais , Comportamento Alimentar/efeitos dos fármacos , Feminino , Células HEK293 , Humanos , Mordeduras e Picadas de Insetos , Receptores de Neuropeptídeo Y/metabolismo , Bibliotecas de Moléculas Pequenas/análiseRESUMO
The previously published version of this Article contained errors in Fig. 6. In panel h the units of the x axis were incorrectly given as mM and should have been given as µM. Also, the IC50s for RU.365, RU.332 and RU.521 within panel h were incorrectly given as mM and should have been given as µM. These errors have been corrected in both the PDF and HTML versions of the Article.
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Cyclic GMP-AMP synthase is essential for innate immunity against infection and cellular damage, serving as a sensor of DNA from pathogens or mislocalized self-DNA. Upon binding double-stranded DNA, cyclic GMP-AMP synthase synthesizes a cyclic dinucleotide that initiates an inflammatory cellular response. Mouse studies that recapitulate causative mutations in the autoimmune disease Aicardi-Goutières syndrome demonstrate that ablating the cyclic GMP-AMP synthase gene abolishes the deleterious phenotype. Here, we report the discovery of a class of cyclic GMP-AMP synthase inhibitors identified by a high-throughput screen. These compounds possess defined structure-activity relationships and we present crystal structures of cyclic GMP-AMP synthase, double-stranded DNA, and inhibitors within the enzymatic active site. We find that a chemically improved member, RU.521, is active and selective in cellular assays of cyclic GMP-AMP synthase-mediated signaling and reduces constitutive expression of interferon in macrophages from a mouse model of Aicardi-Goutières syndrome. RU.521 will be useful toward understanding the biological roles of cyclic GMP-AMP synthase and can serve as a molecular scaffold for development of future autoimmune therapies.Upon DNA binding cyclic GMP-AMP synthase (cGAS) produces a cyclic dinucleotide, which leads to the upregulation of inflammatory genes. Here the authors develop small molecule cGAS inhibitors, functionally characterize them and present the inhibitor and DNA bound cGAS crystal structures, which will facilitate drug development.
Assuntos
Doenças Autoimunes/imunologia , Autoimunidade/efeitos dos fármacos , Benzofuranos/farmacologia , Inibidores Enzimáticos/farmacologia , Macrófagos/efeitos dos fármacos , Animais , Doenças Autoimunes do Sistema Nervoso/imunologia , Autoimunidade/imunologia , DNA/metabolismo , Ensaios de Triagem em Larga Escala , Imunidade Inata/imunologia , Inflamação , Macrófagos/imunologia , Espectrometria de Massas , Camundongos , Malformações do Sistema Nervoso/imunologia , Nucleotidiltransferases/antagonistas & inibidores , Nucleotidiltransferases/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas , Relação Estrutura-AtividadeRESUMO
We have developed a new high-content cytotoxicity assay using live cells, called "ImageTOX." We used a high-throughput fluorescence microscope system, image segmentation software, and the combination of Hoechst 33342 and SYTO 17 to simultaneously score the relative size and the intensity of the nuclei, the nuclear membrane permeability, and the cell number in a 384-well microplate format. We then performed a screen of 12,668 diverse compounds and compared the results to a standard cytotoxicity assay. The ImageTOX assay identified similar sets of compounds to the standard cytotoxicity assay, while identifying more compounds having adverse effects on cell structure, earlier in treatment time. The ImageTOX assay uses inexpensive commercially available reagents and facilitates the use of live cells in toxicity screens. Furthermore, we show that we can measure the kinetic profile of compound toxicity in a high-content, high-throughput format, following the same set of cells over an extended period of time.
RESUMO
The prototypical second messenger cAMP regulates a wide variety of physiological processes. It can simultaneously mediate diverse functions by acting locally in independently regulated microdomains. In mammalian cells, two types of adenylyl cyclase generate cAMP: G-protein-regulated transmembrane adenylyl cyclases and bicarbonate-, calcium- and ATP-regulated soluble adenylyl cyclase (sAC). Because each type of cyclase regulates distinct microdomains, methods to distinguish between them are needed to understand cAMP signaling. We developed a mass-spectrometry-based adenylyl cyclase assay, which we used to identify a new sAC-specific inhibitor, LRE1. LRE1 bound to the bicarbonate activator binding site and inhibited sAC via a unique allosteric mechanism. LRE1 prevented sAC-dependent processes in cellular and physiological systems, and it will facilitate exploration of the therapeutic potential of sAC inhibition.
Assuntos
Inibidores de Adenilil Ciclases/farmacologia , Adenilil Ciclases/metabolismo , Pirimidinas/farmacologia , Tiofenos/farmacologia , Inibidores de Adenilil Ciclases/química , Adenilil Ciclases/química , Regulação Alostérica/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Modelos Moleculares , Estrutura Molecular , Pirimidinas/química , Solubilidade , Relação Estrutura-Atividade , Tiofenos/químicaRESUMO
The signaling molecule cAMP regulates functions ranging from bacterial transcription to mammalian memory. In mammals, cAMP is synthesized by nine transmembrane adenylyl cyclases (ACs) and one soluble AC (sAC). Despite similarities in their catalytic domains, these ACs differ in regulation. Transmembrane ACs respond to G proteins, whereas sAC is uniquely activated by bicarbonate. Via bicarbonate regulation, sAC acts as a physiological sensor for pH/bicarbonate/CO2, and it has been implicated as a therapeutic target, e.g. for diabetes, glaucoma, and a male contraceptive. Here we identify the bisphenols bithionol and hexachlorophene as potent, sAC-specific inhibitors. Inhibition appears mostly non-competitive with the substrate ATP, indicating that they act via an allosteric site. To analyze the interaction details, we solved a crystal structure of an sAC·bithionol complex. The structure reveals that the compounds are selective for sAC because they bind to the sAC-specific, allosteric binding site for the physiological activator bicarbonate. Structural comparison of the bithionol complex with apo-sAC and other sAC·ligand complexes along with mutagenesis experiments reveals an allosteric mechanism of inhibition; the compound induces rearrangements of substrate binding residues and of Arg(176), a trigger between the active site and allosteric site. Our results thus provide 1) novel insights into the communication between allosteric regulatory and active sites, 2) a novel mechanism for sAC inhibition, and 3) pharmacological compounds targeting this allosteric site and utilizing this mode of inhibition. These studies provide support for the future development of sAC-modulating drugs.
Assuntos
Trifosfato de Adenosina/química , Adenilil Ciclases/química , Bicarbonatos/química , Bitionol/química , Regulação Alostérica , Domínio Catalítico , Cristalografia por Raios X , HumanosRESUMO
Suppression of RAD52 causes synthetic lethality in BRCA-deficient cells. Yet pharmacological inhibition of RAD52, which binds single-strand DNA (ssDNA) and lacks enzymatic activity, has not been demonstrated. Here, we identify the small molecule 6-hydroxy-DL-dopa (6-OH-dopa) as a major allosteric inhibitor of the RAD52 ssDNA binding domain. For example, we find that multiple small molecules bind to and completely transform RAD52 undecamer rings into dimers, which abolishes the ssDNA binding channel observed in crystal structures. 6-OH-Dopa also disrupts RAD52 heptamer and undecamer ring superstructures, and suppresses RAD52 recruitment and recombination activity in cells with negligible effects on other double-strand break repair pathways. Importantly, we show that 6-OH-dopa selectively inhibits the proliferation of BRCA-deficient cancer cells, including those obtained from leukemia patients. Taken together, these data demonstrate small-molecule disruption of RAD52 rings as a promising mechanism for precision medicine in BRCA-deficient cancers.
Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Proteína Rad52 de Recombinação e Reparo de DNA/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas/química , Regulação Alostérica , Apoptose/efeitos dos fármacos , Proteína BRCA1/deficiência , Proteína BRCA2/deficiência , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , DNA de Cadeia Simples/química , DNA de Cadeia Simples/metabolismo , Di-Hidroxifenilalanina/análogos & derivados , Di-Hidroxifenilalanina/química , Di-Hidroxifenilalanina/metabolismo , Di-Hidroxifenilalanina/toxicidade , Ensaio de Desvio de Mobilidade Eletroforética , Humanos , Concentração Inibidora 50 , Microscopia de Fluorescência , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Ligação Proteica , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Proteína Rad52 de Recombinação e Reparo de DNA/genética , Proteína Rad52 de Recombinação e Reparo de DNA/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Bibliotecas de Moléculas Pequenas/metabolismo , Bibliotecas de Moléculas Pequenas/toxicidadeRESUMO
Farnesyl pyrophosphate synthase (FPPS) is an established target for the treatment of bone diseases, but also shows promise as an anticancer and anti-infective drug target. Currently available anti-FPPS drugs are active-site-directed bisphosphonate inhibitors, the peculiar pharmacological profile of which is inadequate for therapeutic indications beyond bone diseases. The recent discovery of an allosteric binding site has paved the way toward the development of novel non-bisphosphonate FPPS inhibitors with broader therapeutic potential, notably as immunomodulators in oncology. Herein we report the discovery, by an integrated lead finding approach, of two new chemical classes of allosteric FPPS inhibitors that belong to the salicylic acid and quinoline chemotypes. We present their synthesis, biochemical and cellular activities, structure-activity relationships, and provide X-ray structures of several representative FPPS complexes. These novel allosteric FPPS inhibitors are devoid of any affinity for bone mineral and could serve as leads to evaluate their potential in none-bone diseases.
Assuntos
Descoberta de Drogas , Inibidores Enzimáticos/farmacologia , Geraniltranstransferase/antagonistas & inibidores , Quinolinas/farmacologia , Ácido Salicílico/farmacologia , Regulação Alostérica/efeitos dos fármacos , Sítio Alostérico/efeitos dos fármacos , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Geraniltranstransferase/metabolismo , Humanos , Estrutura Molecular , Quinolinas/síntese química , Quinolinas/química , Ácido Salicílico/síntese química , Ácido Salicílico/química , Relação Estrutura-AtividadeRESUMO
Most cancer therapies involve a component of treatment that inflicts DNA damage in tumor cells, such as double-strand breaks (DSBs), which are considered the most serious threat to genomic integrity. Complex systems have evolved to repair these lesions, and successful DSB repair is essential for tumor cell survival after exposure to ionizing radiation (IR) and other DNA-damaging agents. As such, inhibition of DNA repair is a potentially efficacious strategy for chemo- and radiosensitization. Homologous recombination (HR) and nonhomologous end-joining (NHEJ) represent the two major pathways by which DSBs are repaired in mammalian cells. Here, we report the design and execution of a high-throughput, cell-based small molecule screen for novel DSB repair inhibitors. We miniaturized our recently developed dual NHEJ and HR reporter system into a 384-well plate-based format and interrogated a diverse library of 20,000 compounds for molecules that selectively modulate NHEJ and HR repair in tumor cells. We identified a collection of novel hits that potently inhibit DSB repair, and we have validated their functional activity in a comprehensive panel of orthogonal secondary assays. A selection of these inhibitors was found to radiosensitize cancer cell lines in vitro, which suggests that they may be useful as novel chemo- and radio sensitizers. Surprisingly, we identified several FDA-approved drugs, including the calcium channel blocker mibefradil dihydrochloride, that demonstrated activity as DSB repair inhibitors and radiosensitizers. These findings suggest the possibility for repurposing them as tumor cell radiosensitizers in the future. Accordingly, we recently initiated a phase I clinical trial testing mibefradil as a glioma radiosensitizer.
Assuntos
Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Ensaios de Triagem em Larga Escala/métodos , Radiossensibilizantes/farmacologia , Linhagem Celular Tumoral , Proteínas de Fluorescência Verde/metabolismo , Recombinação Homóloga/efeitos dos fármacos , Humanos , Projetos Piloto , Reprodutibilidade dos Testes , Bibliotecas de Moléculas Pequenas/farmacologiaRESUMO
Has the impact of irreproducibility on the discovery and development of drugs, as with global warming, metaphorically speaking, crept up on us as we slept? Or is the problem more an issue of heightened awareness? We currently find ourselves in a time when the impact of irreproducibility can easily be amplified by the combinatorial effect of our increasing reliance on advanced technologies and unrealistic expectations of how scientific truths unfold. How and why we got here is a topic that has been written on extensively (1-3) and is probably as complex as any other problem, given the dependence of science today on so many external forces. Through a series of questions, we asked members of our editorial board their opinions on scientific irreproducibility. They chose to answer the same questions from different levels, indicating the depth of the problem and perhaps where they each believe change for the better needs to begin. My thanks to the participants.