RESUMO
Nephronophthisis (NPHP), Joubert (JBTS), and Meckel-Gruber (MKS) syndromes are autosomal-recessive ciliopathies presenting with cystic kidneys, retinal degeneration, and cerebellar/neural tube malformation. Whether defects in kidney, retinal, or neural disease primarily involve ciliary, Hedgehog, or cell polarity pathways remains unclear. Using high-confidence proteomics, we identified 850 interactors copurifying with nine NPHP/JBTS/MKS proteins and discovered three connected modules: "NPHP1-4-8" functioning at the apical surface, "NPHP5-6" at centrosomes, and "MKS" linked to Hedgehog signaling. Assays for ciliogenesis and epithelial morphogenesis in 3D renal cultures link renal cystic disease to apical organization defects, whereas ciliary and Hedgehog pathway defects lead to retinal or neural deficits. Using 38 interactors as candidates, linkage and sequencing analysis of 250 patients identified ATXN10 and TCTN2 as new NPHP-JBTS genes, and our Tctn2 mouse knockout shows neural tube and Hedgehog signaling defects. Our study further illustrates the power of linking proteomic networks and human genetics to uncover critical disease pathways.
Assuntos
Doenças Renais Císticas/genética , Proteínas de Membrana/genética , Transdução de Sinais , Animais , Ataxina-10 , Centrossomo/metabolismo , Cílios/metabolismo , Transtornos da Motilidade Ciliar/genética , Encefalocele/genética , Proteínas Hedgehog/metabolismo , Humanos , Doenças Renais Císticas/metabolismo , Camundongos , Células NIH 3T3 , Proteínas do Tecido Nervoso/genética , Doenças Renais Policísticas/genética , Retinose Pigmentar , Peixe-ZebraRESUMO
Intact protein mass spectrometry (MS) coupled with liquid chromatography was applied to characterize the pharmacokinetics and stability profiles of therapeutic proteins. However, limitations from chromatography, including throughput and carryover, result in challenges with handling large sample numbers. Here, we combined intact protein MS with multiple front-end separations, including affinity capture, SampleStream, and high-field asymmetric waveform ion mobility spectrometry (FAIMS), to perform high-throughput and specific mass measurements of a multivalent antibody with one antigen-binding fragment (Fab) fused to an immunoglobulin G1 (IgG1) antibody. Generic affinity capture ensures the retention of both intact species 1Fab-IgG1 and the tentative degradation product IgG1. Subsequently, the analytes were directly loaded into SampleStream, where each injection occurs within â¼30 s. By separating ions prior to MS detection, FAIMS further offered improvement in signal-overnoise by â¼30% for denatured protein MS via employing compensation voltages that were optimized for different antibody species. When enhanced FAIMS transmission of 1Fab-IgG1 was employed, a qualified assay was established for spiked-in serum samples between 0.1 and 25 µg/mL, resulting in â¼10% accuracy bias and precision coefficient of variation. Selective FAIMS transmission of IgG1 as the degradation surrogate product enabled more sensitive detection of clipped species for intact 1Fab-IgG1 at 5 µg/mL in serum, generating an assay to measure 1Fab-IgG1 truncation between 2.5 and 50% with accuracy and precision below 20% bias and coefficient of variation. Our results revealed that the SampleStream-FAIMS-MS platform affords high throughput, selectivity, and sensitivity for characterizing therapeutic antibodies from complex biomatrices qualitatively and quantitatively.
Assuntos
Imunoglobulina G , Espectrometria de Mobilidade Iônica , Espectrometria de Mobilidade Iônica/métodos , Espectrometria de Massas/métodos , Cromatografia Líquida , Íons/químicaRESUMO
TREM2 is an Alzheimer's disease (AD) risk gene expressed in microglia. To study the role of Trem2 in a mouse model of ß-amyloidosis, we compared PS2APP transgenic mice versus PS2APP mice lacking Trem2 (PS2APP;Trem2ko) at ages ranging from 4 to 22 months. Microgliosis was impaired in PS2APP;Trem2ko mice, with Trem2-deficient microglia showing compromised expression of proliferation/Wnt-related genes and marked accumulation of ApoE. Plaque abundance was elevated in PS2APP;Trem2ko females at 6-7 months; but by 12 or 19-22 months of age, it was notably diminished in female and male PS2APP;Trem2ko mice, respectively. Across all ages, plaque morphology was more diffuse in PS2APP;Trem2ko brains, and the Aß42:Aß40 ratio was elevated. The amount of soluble, fibrillar Aß oligomers also increased in PS2APP;Trem2ko hippocampi. Associated with these changes, axonal dystrophy was exacerbated from 6 to 7 months onward in PS2APP;Trem2ko mice, notwithstanding the reduced plaque load at later ages. PS2APP;Trem2ko mice also exhibited more dendritic spine loss around plaque and more neurofilament light chain in CSF. Thus, aggravated neuritic dystrophy is a more consistent outcome of Trem2 deficiency than amyloid plaque load, suggesting that the microglial packing of Aß into dense plaque is an important neuroprotective activity.SIGNIFICANCE STATEMENT Genetic studies indicate that TREM2 gene mutations confer increased Alzheimer's disease (AD) risk. We studied the effects of Trem2 deletion in the PS2APP mouse AD model, in which overproduction of Aß peptide leads to amyloid plaque formation and associated neuritic dystrophy. Interestingly, neuritic dystrophies were intensified in the brains of Trem2-deficient mice, despite these mice displaying reduced plaque accumulation at later ages (12-22 months). Microglial clustering around plaques was impaired, plaques were more diffuse, and the Aß42:Aß40 ratio and amount of soluble, fibrillar Aß oligomers were elevated in Trem2-deficient brains. These results suggest that the Trem2-dependent compaction of Aß into dense plaques is a protective microglial activity, limiting the exposure of neurons to toxic Aß species.
Assuntos
Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Axônios/patologia , Espinhas Dendríticas/patologia , Glicoproteínas de Membrana/genética , Fragmentos de Peptídeos/metabolismo , Placa Amiloide/genética , Receptores Imunológicos/genética , Fator Trefoil-1/metabolismo , Animais , Feminino , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/patologia , Neuritos/patologia , Proteínas de Neurofilamentos/líquido cefalorraquidiano , Placa Amiloide/patologiaRESUMO
Fusion of biologic therapeutics to hyaluronic acid binding proteins, such as the link domain (LD) of Tumor necrosis factor (TNF)-Stimulated Gene-6 (TSG-6), is expected to increase vitreous residence time following intravitreal injection and provide for long-acting delivery. The toxicity of a single intravitreal dose of free TSG-6-LD and fusion proteins of TSG-6-LD and a nonbinding rabbit antibody fragment (RabFab) were assessed in New Zealand White rabbits. Animals administered free TSG-6-LD exhibited extensive lens opacities and variable retinal vascular attenuation, correlated with microscopic findings of lens and retinal degeneration. Similar but less severe findings were present in animals dosed with the RabFab-TSG-6-LD fusion proteins. In-life ocular inflammation was noted in all animals from 7-days postdose and was associated with high anti-RabFab antibody titers in animals administered fusion proteins. Inflammation and retinal degeneration were multifocally associated with evidence of retinal detachment, and hypertrophy and migration of vimentin, glial fibrillary acidic protein, and glutamine synthetase positive Müller cells to the outer nuclear layer. Further assessment of alternative hyaluronic acid binding protein fusions should consider the potential for retinal degeneration and enhanced immune responses early in development.
Assuntos
Retina , Degeneração Retiniana , Animais , Proteína Glial Fibrilar Ácida , Injeções Intravítreas , Coelhos , Degeneração Retiniana/induzido quimicamenteRESUMO
The membrane of the primary cilium is a highly specialized compartment that organizes proteins to achieve spatially ordered signaling. Disrupting ciliary organization leads to diseases called ciliopathies, with phenotypes ranging from retinal degeneration and cystic kidneys to neural tube defects. How proteins are selectively transported to and organized in the primary cilium remains unclear. Using a proteomic approach, we identified the ARL3 effector UNC119 as a binding partner of the myristoylated ciliopathy protein nephrocystin-3 (NPHP3). We mapped UNC119 binding to the N-terminal 200 residues of NPHP3 and found the interaction requires myristoylation. Creating directed mutants predicted from a structural model of the UNC119-myristate complex, we identified highly conserved phenylalanines within a hydrophobic ß sandwich to be essential for myristate binding. Furthermore, we found that binding of ARL3-GTP serves to release myristoylated cargo from UNC119. Finally, we showed that ARL3, UNC119b (but not UNC119a), and the ARL3 GAP Retinitis Pigmentosa 2 (RP2) are required for NPHP3 ciliary targeting and that targeting requires UNC119b myristoyl-binding activity. Our results uncover a selective, membrane targeting GTPase cycle that delivers myristoylated proteins to the ciliary membrane and suggest that other myristoylated proteins may be similarly targeted to specialized membrane domains.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Caenorhabditis elegans , Cílios/metabolismo , GTP Fosfo-Hidrolases/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Cinesinas , Proteínas Monoméricas de Ligação ao GTP , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Sequência de Aminoácidos , Animais , Caenorhabditis elegans/enzimologia , Caenorhabditis elegans/genética , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/química , Proteínas de Caenorhabditis elegans/metabolismo , Linhagem Celular , Cílios/enzimologia , GTP Fosfo-Hidrolases/genética , Técnicas de Silenciamento de Genes , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Cinesinas/genética , Cinesinas/metabolismo , Proteínas Monoméricas de Ligação ao GTP/genética , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Mutação , Fenótipo , Ligação Proteica , Estrutura Terciária de Proteína , Transporte Proteico , Alinhamento de Sequência , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismoRESUMO
Metabolic reprogramming in tumors represents a potential therapeutic target. Herein we used shRNA depletion and a novel lactate dehydrogenase (LDHA) inhibitor, GNE-140, to probe the role of LDHA in tumor growth in vitro and in vivo. In MIA PaCa-2 human pancreatic cells, LDHA inhibition rapidly affected global metabolism, although cell death only occurred after 2 d of continuous LDHA inhibition. Pancreatic cell lines that utilize oxidative phosphorylation (OXPHOS) rather than glycolysis were inherently resistant to GNE-140, but could be resensitized to GNE-140 with the OXPHOS inhibitor phenformin. Acquired resistance to GNE-140 was driven by activation of the AMPK-mTOR-S6K signaling pathway, which led to increased OXPHOS, and inhibitors targeting this pathway could prevent resistance. Thus, combining an LDHA inhibitor with compounds targeting the mitochondrial or AMPK-S6K signaling axis may not only broaden the clinical utility of LDHA inhibitors beyond glycolytically dependent tumors but also reduce the emergence of resistance to LDHA inhibition.
Assuntos
Plasticidade Celular/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , L-Lactato Desidrogenase/antagonistas & inibidores , Piridonas/farmacologia , Tiofenos/farmacologia , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/química , Humanos , L-Lactato Desidrogenase/metabolismo , Modelos Moleculares , Estrutura Molecular , Piridonas/química , Relação Estrutura-Atividade , Tiofenos/químicaRESUMO
Somatic mutation of isocitrate dehydrogenase 1 (IDH1) is now recognized as the most common initiating event for secondary glioblastoma, a brain tumor type arising with high frequency in the frontal lobe. A puzzling feature of IDH1 mutation is the selective manifestation of glioma as the only neoplasm frequently associated with early postzygotic occurrence of this genomic alteration. We report here that IDH1(R132H) exhibits a growth-inhibitory effect that is abrogated in the presence of glutamate dehydrogenase 2 (GLUD2), a hominoid-specific enzyme purportedly optimized to facilitate glutamate turnover in human forebrain. Using murine glioma progenitor cells, we demonstrate that IDH1(R132H) exerts a growth-inhibitory effect that is paralleled by deficiency in metabolic flux from glucose and glutamine to lipids. Examining human gliomas, we find that glutamate dehydrogenase 1 (GLUD1) and GLUD2 are overexpressed in IDH1-mutant tumors and that orthotopic growth of an IDH1-mutant glioma line is inhibited by knockdown of GLUD1/2. Strikingly, introduction of GLUD2 into murine glioma progenitor cells reverses deleterious effects of IDH1 mutation on metabolic flux and tumor growth. Further, we report that glutamate, a substrate of GLUD2 and a neurotransmitter abundant in mammalian neocortex, can support growth of glioma progenitor cells irrespective of IDH1 mutation status. These findings suggest that specialization of human neocortex for high glutamate neurotransmitter flux creates a metabolic niche conducive to growth of IDH1 mutant tumors.
Assuntos
Neoplasias Encefálicas/enzimologia , Neoplasias Encefálicas/genética , Glioma/enzimologia , Glioma/genética , Glutamato Desidrogenase/genética , Glutamato Desidrogenase/metabolismo , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Substituição de Aminoácidos , Animais , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Feminino , Técnicas de Silenciamento de Genes , Genes p53 , Glioma/patologia , Glutamato Desidrogenase/antagonistas & inibidores , Ácido Glutâmico/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos NOD , Camundongos Nus , Camundongos SCID , Células-Tronco Neoplásicas/enzimologia , Células-Tronco Neoplásicas/patologia , Receptores de Glutamato/genética , Receptores de Glutamato/metabolismoRESUMO
Joubert syndrome (JS) is characterized by a distinctive cerebellar structural defect, namely the << molar tooth sign >>. JS is genetically heterogeneous, involving 20 genes identified to date, which are all required for cilia biogenesis and/or function. In a consanguineous family with JS associated with optic nerve coloboma, kidney hypoplasia, and polydactyly, combined exome sequencing and mapping identified a homozygous splice-site mutation in PDE6D, encoding a prenyl-binding protein. We found that pde6d depletion in zebrafish leads to renal and retinal developmental anomalies and wild-type but not mutant PDE6D is able to rescue this phenotype. Proteomic analysis identified INPP5E, whose mutations also lead to JS or mental retardation, obesity, congenital retinal dystrophy, and micropenis syndromes, as novel prenyl-dependent cargo of PDE6D. Mutant PDE6D shows reduced binding to INPP5E, which fails to localize to primary cilia in patient fibroblasts and tissues. Furthermore, mutant PDE6D is unable to bind to GTP-bound ARL3, which acts as a cargo-release factor for PDE6D-bound INPP5E. Altogether, these results indicate that PDE6D is required for INPP5E ciliary targeting and suggest a broader role for PDE6D in targeting other prenylated proteins to the cilia. This study identifies PDE6D as a novel JS disease gene and provides the first evidence of prenyl-binding-dependent trafficking in ciliopathies.
Assuntos
Doenças Cerebelares/genética , Doenças Cerebelares/metabolismo , Cílios/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/genética , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/metabolismo , Anormalidades do Olho/genética , Anormalidades do Olho/metabolismo , Doenças Renais Císticas/genética , Doenças Renais Císticas/metabolismo , Monoéster Fosfórico Hidrolases/genética , Monoéster Fosfórico Hidrolases/metabolismo , Retina/anormalidades , Fatores de Ribosilação do ADP/metabolismo , Anormalidades Múltiplas , Animais , Cerebelo/anormalidades , Exoma , Feminino , Predisposição Genética para Doença , Homozigoto , Humanos , Masculino , Modelos Moleculares , Linhagem , Prenilação de Proteína , Proteômica , Retina/metabolismo , Análise de Sequência de DNA , Peixe-Zebra/anormalidades , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismoRESUMO
BACKGROUND AND PURPOSE: RO7502175 is an afucosylated antibody designed to eliminate C-C motif chemokine receptor 8 (CCR8)+ Treg cells in the tumour microenvironment through enhanced antibody-dependent cellular cytotoxicity (ADCC). EXPERIMENTAL APPROACH: We report findings from preclinical studies characterizing pharmacology, pharmacokinetics (PK)/pharmacodynamics (PD) and safety profile of RO7502175 and discuss the translational PK/PD approach used to inform first-in-human (FiH) dosing strategy and clinical development in solid tumour indications. KEY RESULTS: RO7502175 demonstrated selective ADCC against human CCR8+ Treg cells from dissociated tumours in vitro. In cynomolgus monkeys, RO7502175 exhibited a biphasic concentration-time profile consistent with immunoglobulin G1 (IgG1) antibodies, reduced CCR8+ Treg cells in the blood, induced minimal and transient cytokine secretion, and was well tolerated with a no-observed-adverse-effect level (NOAEL) of 100 mg·kg-1. Moreover, RO7502175 caused minimal cytokine release from peripheral blood mononuclear cells (PBMCs) in vitro. A quantitative model was developed to capture surrogate anti-murine CCR8 antibody PK/PD and tumour dynamics in mice and RO7502175 PK/PD in cynomolgus monkeys. Subsequently, the model was used to project RO7502175 human PK and receptor occupancy (RO) in patients. Because traditional approaches resulted in a low FiH dose for this molecule, even with its superior preclinical safety profile, an integrated approach based on the totality of preclinical data and modelling insights was used for starting dose selection. CONCLUSION AND IMPLICATIONS: This work demonstrates a translational research strategy for collecting and utilizing relevant nonclinical data, developing a mechanistic PK/PD model and using a comprehensive approach to inform clinical study design for RO7502175.
Assuntos
Macaca fascicularis , Receptores CCR8 , Linfócitos T Reguladores , Animais , Humanos , Linfócitos T Reguladores/efeitos dos fármacos , Linfócitos T Reguladores/imunologia , Receptores CCR8/antagonistas & inibidores , Receptores CCR8/imunologia , Camundongos , Feminino , Masculino , Pesquisa Translacional Biomédica , Anticorpos Monoclonais/farmacocinética , Anticorpos Monoclonais/farmacologia , Anticorpos Monoclonais/administração & dosagem , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Relação Dose-Resposta a Droga , Citotoxicidade Celular Dependente de Anticorpos/efeitos dos fármacosRESUMO
FLT3L-Fc is a half-life extended, effectorless Fc-fusion of the native human FLT3-ligand. In cynomolgus monkeys, treatment with FLT3L-Fc leads to a complex pharmacokinetic/pharmacodynamic (PK/PD) relationship, with observed nonlinear PK and expansion of different immune cell types across different dose levels. A minimal physiologically based PK/PD model with expansion-enhanced target-mediated drug disposition (TMDD) was developed to integrate the molecule's mechanism of action, as well as the complex preclinical and clinical PK/PD data, to support the preclinical-to-clinical translation of FLT3L-Fc. In addition to the preclinical PK data of FLT3L-Fc in cynomolgus monkeys, clinical PK and PD data from other FLT3-agonist molecules (GS-3583 and CDX-301) were used to inform the model and project the expansion profiles of conventional DC1s (cDC1s) and total DCs in peripheral blood. This work constitutes an essential part of our model-informed drug development (MIDD) strategy for clinical development of FLT3L-Fc by projecting PK/PD in healthy volunteers, determining the first-in-human (FIH) dose, and informing the efficacious dose in clinical settings. Model-generated results were incorporated in regulatory filings to support the rationale for the FIH dose selection.
RESUMO
Inhibiting MerTK on macrophages is a promising therapeutic strategy for augmenting anti-tumor immunity. However, blocking MerTK on retinal pigment epithelial cells (RPEs) results in retinal toxicity. Bispecific antibodies (bsAbs) containing an anti-MerTK therapeutic and anti-PD-L1 targeting arm were developed to reduce drug binding to MerTK on RPEs, since PD-L1 is overexpressed on macrophages but not RPEs. In this study, we present a modeling framework using in vitro receptor occupancy (RO) and pharmacokinetics (PK) data to predict efficacy, toxicity, and therapeutic index (TI) of anti-MerTK bsAbs. We first used simulations and in vitro RO data of anti-MerTK monospecific antibody (msAb) to estimate the required MerTK RO for in vivo efficacy and toxicity. Using these estimated RO thresholds, we employed our model to predict the efficacious and toxic doses for anti-MerTK bsAbs with varying affinities for MerTK. Our model predicted the highest TI for the anti-MerTK/PD-L1 bsAb with an attenuated MerTK binding arm, which was consistent with in vivo efficacy and toxicity observations. Subsequently, we used the model, in combination with sensitivity analysis and parameter scans, to suggest an optimal molecular design of anti-MerTK bsAb with the highest predicted TI in humans. Our prediction revealed that this optimized anti-MerTK bsAb should contain a MerTK therapeutic arm with relatively low affinity, along with a high affinity targeting arm that can bind to a low abundance target with slow turnover rate. Overall, these results demonstrated that our modeling framework can guide the rational design of bsAbs.
Assuntos
Anticorpos Biespecíficos , Humanos , Antígeno B7-H1 , c-Mer Tirosina QuinaseRESUMO
Certain plant extracts (PEs) contain bioactive compounds that have antioxidant and lifespan-extending activities on organisms. These PEs play different roles in cellular processes, such as enhancing stress resistance and modulating longevity-defined signaling pathways that contribute to longevity. Here, we report the discovery of PEs that extended chronological life span (CLS) in budding yeast from a screen of 222 PEs. We identified two PEs, the leaf extracts of Manihot esculenta and Wodyetia bifurcata that extended CLS in a dose-dependent manner. The CLS-extending PEs also conferred oxidative stress tolerance, suggesting that these PEs might extend yeast CLS through the upregulation of stress response pathways.
Assuntos
Extratos Vegetais/farmacologia , Plantas/química , Saccharomyces cerevisiae/fisiologia , Clima Tropical , Resposta ao Choque Térmico/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Compostos Fitoquímicos/análise , Saccharomyces cerevisiae/efeitos dos fármacosRESUMO
This study compared the chronological life span and survival of Saccharomyces cerevisiae aged in a microplate or bottle, under different aeration and calorie restriction conditions. Our data shows that limited aeration in the microplate-aged culture contributed to slower outgrowth but extended yeast CLS compared to the bottle-aged culture.
Assuntos
Técnicas Microbiológicas/métodos , Saccharomyces cerevisiae/crescimento & desenvolvimento , Restrição Calórica , Viabilidade Microbiana , Técnicas Microbiológicas/instrumentaçãoRESUMO
The enzyme glutaminase (GLS1) is currently in clinical trials for oncology, yet there are no clear diagnostic criteria to identify responders. The evaluation of 25 basal breast lines expressing GLS1, predominantly through its splice isoform GAC, demonstrated that only GLS1-dependent basal B lines required it for maintaining de novo glutathione synthesis in addition to mitochondrial bioenergetics. Drug sensitivity profiling of 407 tumor lines with GLS1 and gamma-glutamylcysteine synthetase (GCS) inhibitors revealed a high degree of co-dependency on both enzymes across indications, suggesting that redox balance is a key function of GLS1 in tumors. To leverage these findings, we derived a pan-cancer metabolic signature predictive of GLS1/GCS co-dependency and validated it in vivo using four lung patient-derived xenograft models, revealing the additional requirement for expression of GAC above a threshold (log2RPKM + 1 ≥ 4.5, where RPKM is reads per kilobase per million mapped reads). Analysis of the pan-TCGA dataset with our signature identified multiple indications, including mesenchymal tumors, as putative responders to GLS1 inhibitors.
Assuntos
Neoplasias da Mama , Glutamato-Cisteína Ligase , Glutaminase , Neoplasias Pulmonares , Células-Tronco Mesenquimais , Metaboloma , Animais , Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Ácido Cítrico/metabolismo , Bases de Dados Genéticas , Feminino , Glutamato-Cisteína Ligase/antagonistas & inibidores , Glutamato-Cisteína Ligase/metabolismo , Glutaminase/antagonistas & inibidores , Glutaminase/metabolismo , Glutationa/metabolismo , Células HEK293 , Humanos , Isoenzimas/metabolismo , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/patologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Camundongos SCID , Ensaio Tumoral de Célula-Tronco , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The Nrf1 transcription factor belongs to the CNC subfamily of basic leucine zipper proteins. Knockout of Nrf1 is lethal in mouse embryos, but nothing is known about the cell types that absolutely require its function during development. We show by chimera analysis that Nrf1 is essential for the hepatocyte lineage. Mouse embryonic stem cells lacking Nrf1 developed normally and contributed to most tissues in adult chimeras where Nrf1 is normally expressed. Nrf1-deficient cells contributed to fetal, but not adult, liver cells. Loss of Nrf1 function resulted in liver cell apoptosis in late-gestation chimeric fetuses. Fetal livers from mutant embryos exhibited increased oxidative stress and impaired expression of antioxidant genes, and primary cultures of nrf1(-/-) fetal hepatocytes were sensitive to tert-butyl hydroperoxide-induced cell death, suggesting that impaired antioxidant defense may be responsible for the apoptosis observed in the livers of chimeric mice. In addition, cells deficient in Nrf1 were sensitized to the cytotoxic effects of tumor necrosis factor (TNF). Our results provide in vivo evidence demonstrating an essential role of Nrf1 in the survival of hepatocytes during development. Our results also suggest that Nrf1 may promote cell survival by maintaining redox balance and protecting embryonic hepatocytes from TNF-mediated apoptosis during development.
Assuntos
Apoptose , Proteínas de Ligação a DNA/fisiologia , Fígado/citologia , Oxirredução , Transativadores/fisiologia , Animais , Antioxidantes/metabolismo , Caspase 3 , Caspases/metabolismo , Morte Celular , Divisão Celular , Linhagem da Célula , Sobrevivência Celular , Células Cultivadas , Proteínas de Ligação a DNA/metabolismo , Relação Dose-Resposta a Droga , Embrião de Mamíferos/citologia , Fibroblastos/metabolismo , Glutationa/metabolismo , Hepatócitos/citologia , Hepatócitos/metabolismo , Óperon Lac , Camundongos , Camundongos Endogâmicos C57BL , Modelos Genéticos , Fator 1 Nuclear Respiratório , Fatores Nucleares Respiratórios , Estresse Oxidativo , Isoformas de Proteínas , Espécies Reativas de Oxigênio , Proteínas Recombinantes de Fusão/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Células-Tronco/citologia , Distribuição Tecidual , Transativadores/metabolismo , Fator de Necrose Tumoral alfa/metabolismoRESUMO
Nicotinamide adenine dinucleotide (NAD) is a cofactor involved in a wide range of cellular metabolic processes and is a key metabolite required for tumor growth. NAMPT, nicotinamide phosphoribosyltransferase, which converts nicotinamide (NAM) to nicotinamide mononucleotide (NMN), the immediate precursor of NAD, is an attractive therapeutic target as inhibition of NAMPT reduces cellular NAD levels and inhibits tumor growth in vivo. However, there is limited understanding of the metabolic response to NAD depletion across cancer cell lines and whether all cell lines respond in a uniform manner. To explore this we selected two non-small cell lung carcinoma cell lines that are sensitive to the NAMPT inhibitor GNE-617 (A549, NCI-H1334), one that shows intermediate sensitivity (NCI-H441), and one that is insensitive (LC-KJ). Even though NAD was reduced in all cell lines there was surprising heterogeneity in their metabolic response. Both sensitive cell lines reduced glycolysis and levels of di- and tri-nucleotides and modestly increased oxidative phosphorylation, but they differed in their ability to combat oxidative stress. H1334 cells activated the stress kinase AMPK, whereas A549 cells were unable to activate AMPK as they contain a mutation in LKB1, which prevents activation of AMPK. However, A549 cells increased utilization of the Pentose Phosphate pathway (PPP) and had lower reactive oxygen species (ROS) levels than H1334 cells, indicating that A549 cells are better able to modulate an increase in oxidative stress. Inherent resistance of LC-KJ cells is associated with higher baseline levels of NADPH and a delayed reduction of NAD upon NAMPT inhibition. Our data reveals that cell lines show heterogeneous response to NAD depletion and that the underlying molecular and genetic framework in cells can influence the metabolic response to NAMPT inhibition.
Assuntos
NAD/metabolismo , Transporte Biológico/efeitos dos fármacos , Linhagem Celular Tumoral , Inibidores Enzimáticos/farmacologia , Glutamina/metabolismo , Humanos , Nicotinamida Fosforribosiltransferase/antagonistas & inibidores , Estresse Oxidativo/efeitos dos fármacos , Fosforilação/efeitos dos fármacosRESUMO
Interferons-alpha (IFN-α) are the expressed gene products comprising thirteen type I interferons with protein pairwise sequence similarities in the 77-96% range. Three other widely expressed human type I interferons, IFN-ß, IFN-κ and IFN-ω have sequences 29-33%, 29-32% and 56-60% similar to the IFN-αs, respectively. Type I interferons act on immune cells by producing subtly different immune-modulatory effects upon binding to the extracellular domains of a heterodimeric cell-surface receptor composed of IFNAR1 and IFNAR2, most notably anti-viral effects. IFN-α has been used to treat infection by hepatitis-virus type C (HCV) and a correlation between hyperactivity of IFN-α-induced signaling and systemic lupus erythematosis (SLE), or lupus, has been noted. Anti-IFN-α antibodies including rontalizumab have been under clinical study for the treatment of lupus. To better understand the rontalizumab mechanism of action and specificity, we determined the X-ray crystal structure of the Fab fragment of rontalizumab bound to human IFN-α2 at 3Å resolution and find substantial overlap of the antibody and IFNA2 epitopes on IFN-α2.
Assuntos
Anticorpos Monoclonais Humanizados/química , Anticorpos Monoclonais Humanizados/farmacologia , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/farmacologia , Interferon-alfa/antagonistas & inibidores , Interferon-alfa/química , Anticorpos Monoclonais Humanizados/imunologia , Anticorpos Neutralizantes/imunologia , Especificidade de Anticorpos , Sítios de Ligação , Cristalografia por Raios X , Humanos , Fragmentos Fab das Imunoglobulinas/química , Fragmentos Fab das Imunoglobulinas/imunologia , Interferon-alfa/imunologia , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Lúpus Eritematoso Sistêmico/imunologia , Modelos Moleculares , Estrutura Secundária de Proteína , Receptor de Interferon alfa e beta/química , Receptor de Interferon alfa e beta/imunologia , Relação Estrutura-AtividadeRESUMO
Inhibiting NAD biosynthesis by blocking the function of nicotinamide phosphoribosyl transferase (NAMPT) is an attractive therapeutic strategy for targeting tumor metabolism. However, the development of drug resistance commonly limits the efficacy of cancer therapeutics. This study identifies mutations in NAMPT that confer resistance to a novel NAMPT inhibitor, GNE-618, in cell culture and in vivo, thus demonstrating that the cytotoxicity of GNE-618 is on target. We determine the crystal structures of six NAMPT mutants in the apo form and in complex with various inhibitors and use cellular, biochemical and structural data to elucidate two resistance mechanisms. One is the surprising finding of allosteric modulation by mutation of residue Ser165, resulting in unwinding of an α-helix that binds the NAMPT substrate 5-phosphoribosyl-1-pyrophosphate (PRPP). The other mechanism is orthosteric blocking of inhibitor binding by mutations of Gly217. Furthermore, by evaluating a panel of diverse small molecule inhibitors, we unravel inhibitor structure activity relationships on the mutant enzymes. These results provide valuable insights into the design of next generation NAMPT inhibitors that offer improved therapeutic potential by evading certain mechanisms of resistance.
Assuntos
Antineoplásicos/farmacologia , Citocinas/antagonistas & inibidores , Citocinas/química , Resistencia a Medicamentos Antineoplásicos , Inibidores Enzimáticos/farmacologia , Nicotinamida Fosforribosiltransferase/antagonistas & inibidores , Nicotinamida Fosforribosiltransferase/química , Domínio Catalítico , Linhagem Celular Tumoral , Citocinas/genética , Humanos , Modelos Moleculares , Mutação , Nicotinamida Fosforribosiltransferase/genéticaRESUMO
Nicotinamide adenine dinucleotide (NAD) is a critical metabolite that is required for a range of cellular reactions. A key enzyme in the NAD salvage pathway is nicotinamide phosphoribosyl transferase (NAMPT), and here, we describe GNE-618, an NAMPT inhibitor that depletes NAD and induces cell death in vitro and in vivo. While cells proficient for nicotinic acid phosphoribosyl transferase (NAPRT1) can be protected from NAMPT inhibition as they convert nicotinic acid (NA) to NAD independent of the salvage pathway, this protection only occurs if NA is added before NAD depletion. We also demonstrate that tumor cells are unable to generate NAD by de novo synthesis as they lack expression of key enzymes in this pathway, thus providing a mechanistic rationale for the reliance of tumor cells on the NAD salvage pathway. Identifying tumors that are sensitive to NAMPT inhibition is one potential way to enhance the therapeutic effectiveness of an NAMPT inhibitor, and here, we show that NAMPT, but not NAPRT1, mRNA and protein levels inversely correlate with sensitivity to GNE-618 across a panel of 53 non-small cell lung carcinoma cell lines. Finally, we demonstrate that GNE-618 reduced tumor growth in a patient-derived model, which is thought to more closely represent heterogeneous primary patient tumors. Thus, we show that dependence of tumor cells on the NAD salvage pathway renders them sensitive to GNE-618 in vitro and in vivo, and our data support further evaluation of the use of NAMPT mRNA and protein levels as predictors of overall sensitivity.
Assuntos
Antineoplásicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Neoplasias Pulmonares/metabolismo , NAD/metabolismo , Pentosiltransferases/antagonistas & inibidores , Pirazóis/farmacologia , Sulfonas/farmacologia , Animais , Antineoplásicos/uso terapêutico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Xenoenxertos , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Camundongos Nus , Pentosiltransferases/genética , Pirazóis/uso terapêutico , Sulfonas/uso terapêuticoRESUMO
Chemokines play an important role in the immune system by regulating cell trafficking in homeostasis and inflammation. In this study, we report the identification and characterization of a novel cytokine-like protein, DMC (dendritic cell and monocyte chemokine-like protein), which attracts dendritic cells and monocytes. The key to the identification of this putative new chemokine was the application of threading techniques to its uncharacterized sequence. Based on our studies, DMC is predicted to have an IL-8-like chemokine fold and to be structurally and functionally related to CXCL8 and CXCL14. Consistent with our predictions, DMC induces migration of monocytes and immature dendritic cells. Expression studies show that DMC is constitutively expressed in lung, suggesting a potential role for DMC in recruiting monocytes and dendritic cells from blood into lung parenchyma.