RESUMO
BACKGROUND: Wnt signaling plays key roles in cellular and physiological processes, including cell proliferation, differentiation and migration during development and tissue homeostasis in adults. This pathway can be defined as Wnt/ß-catenin-dependent or ß-catenin-independent or "non-canonical", both signaling are involved in neurite and synapse development/maintenance. Porcupine (PORCN), an acylase that o-acylates Wnt ligands, a major modification in secretion and interaction with its receptors. We use Wnt-C59, a specific PORCN inhibitor, to block the secretion of endogenous Wnts in embryonic hippocampal neurons (DIV 4). Under these conditions, the activity of exogenous Wnt ligands on the complexity of the dendritic tree and axonal polarity were evaluated METHODS: Cultured primary embryonic hippocampal neurons obtained from Sprague-Dawley rat fetuses (E18), were cultured until day in vitro (DIV) 4 (according to Banker´s protocol) and treated with Wnt-C59 for 24 h, Wnt ligands were added to the cultures on DIV 3 for 24 h. Dendritic arbors and neurites were analysis by fluorescence microscopy. Transfection with Lipofectamine 2000 on DIV 2 of plasmid expressing eGFP and KIF5-Cherry was carried out to evaluate neuronal polarity. Immunostaining was performed with MAP1B and Tau protein. Immunoblot analysis was carried out with Wnt3a, ß-catenin and GSK-3ß (p-Ser9). Quantitative analysis of dendrite morphology was carried out with ImageJ (NIH) software with Neuron J Plugin. RESULTS: We report, here, that Wnt-C59 treatment changed the morphology of the dendritic arbors and neurites of embryonic hippocampal neurons, with decreases ß-catenin and Wnt3a and an apparent increase in GSK-3ß (p-Ser9) levels. No effect was observed on axonal polarity. In sister cultures, addition of exogenous Wnt3a, 5a and 7a ligands rescued the changes in neuronal morphology. Wnt3a restored the length of neurites to near that of the control, but Wnt7a increased the neurite length beyond that of the control. Wnt5a also restored the length of neurites relative to Wnt concentrations. CONCLUSIONS: Results indicated that Wnt ligands, added exogenously, restored dendritic arbor complexity in embryonic hippocampal neurons, previously treated with a high affinity specific Porcupine inhibitor. We proposed that PORCN is an emerging molecular target of interest in the search for preclinical options to study and treat Wnt-related diseases. Video Abstract.
Assuntos
Glicogênio Sintase Quinase 3 beta/genética , Neurônios/metabolismo , Proteína Wnt3A/genética , beta Catenina/genética , Animais , Axônios/metabolismo , Benzenoacetamidas/farmacologia , Diferenciação Celular/efeitos dos fármacos , Movimento Celular/efeitos dos fármacos , Polaridade Celular/genética , Proliferação de Células/efeitos dos fármacos , Feto , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Hipocampo/crescimento & desenvolvimento , Ligantes , Neuritos/efeitos dos fármacos , Neuritos/metabolismo , Neurônios/efeitos dos fármacos , Proteínas Proto-Oncogênicas/genética , Piridinas/farmacologia , Ratos , Proteínas Wnt/genética , Proteína Wnt-5a/genéticaRESUMO
Many types of cancers have a well-established dependence on glutamine metabolism to support survival and growth, a process linked to glutaminase 1 (GLS) isoforms. Conversely, GLS2 variants often have tumor-suppressing activity. Triple-negative (TN) breast cancer (testing negative for estrogen, progesterone, and Her2 receptors) has elevated GLS protein levels and reportedly depends on exogenous glutamine and GLS activity for survival. Despite having high GLS levels, we verified that several breast cancer cells (including TN cells) express endogenous GLS2, defying its role as a bona fide tumor suppressor. Moreover, ectopic GLS2 expression rescued cell proliferation, TCA anaplerosis, redox balance, and mitochondrial function after GLS inhibition by the small molecule currently in clinical trials CB-839 or GLS knockdown of GLS-dependent cell lines. In several cell lines, GLS2 knockdown decreased cell proliferation and glutamine-linked metabolic phenotypes. Strikingly, long-term treatment of TN cells with another GLS-exclusive inhibitor bis-2'-(5-phenylacetamide-1,3,4-thiadiazol-2-yl)ethyl sulfide (BPTES) selected for a drug-resistant population with increased endogenous GLS2 and restored proliferative capacity. GLS2 was linked to enhanced in vitro cell migration and invasion, mesenchymal markers (through the ERK-ZEB1-vimentin axis under certain conditions) and in vivo lung metastasis. Of concern, GLS2 amplification or overexpression is linked to an overall, disease-free and distant metastasis-free worse survival prognosis in breast cancer. Altogether, these data establish an unforeseen role of GLS2 in sustaining tumor proliferation and underlying metastasis in breast cancer and provide an initial framework for exploring GLS2 as a novel therapeutic target.
Assuntos
Neoplasias da Mama/patologia , Carcinogênese/patologia , Glutaminase/metabolismo , Neoplasias Pulmonares/secundário , Adulto , Idoso , Idoso de 80 Anos ou mais , Benzenoacetamidas/farmacologia , Benzenoacetamidas/uso terapêutico , Mama/patologia , Mama/cirurgia , Neoplasias da Mama/mortalidade , Neoplasias da Mama/terapia , Linhagem Celular Tumoral , Intervalo Livre de Doença , Feminino , Técnicas de Silenciamento de Genes , Glutaminase/antagonistas & inibidores , Humanos , Pessoa de Meia-Idade , Prognóstico , Sulfetos/farmacologia , Sulfetos/uso terapêutico , Tiadiazóis/farmacologia , Tiadiazóis/uso terapêuticoRESUMO
Triple-negative breast cancers (TNBCs) lack progesterone and estrogen receptors and do not have amplified human epidermal growth factor receptor 2, the main therapeutic targets for managing breast cancer. TNBCs have an altered metabolism, including an increased Warburg effect and glutamine dependence, making the glutaminase inhibitor CB-839 therapeutically promising for this tumor type. Accordingly, CB-839 is currently in phase I/II clinical trials. However, not all TNBCs respond to CB-839 treatment, and the tumor resistance mechanism is not yet fully understood. Here we classified cell lines as CB-839-sensitive or -resistant according to their growth responses to CB-839. Compared with sensitive cells, resistant cells were less glutaminolytic and, upon CB-839 treatment, exhibited a smaller decrease in ATP content and less mitochondrial fragmentation, an indicator of poor mitochondrial health. Transcriptional analyses revealed that the expression levels of genes linked to lipid metabolism were altered between sensitive and resistant cells and between breast cancer tissues (available from The Cancer Genome Atlas project) with low versus high glutaminase (GLS) gene expression. Of note, CB-839-resistant TNBC cells had increased carnitine palmitoyltransferase 2 (CPT2) protein and CPT1 activity levels. In agreement, CB-839-resistant TNBC cells mobilized more fatty acids into mitochondria for oxidation, which responded to AMP-activated protein kinase and acetyl-CoA carboxylase signaling. Moreover, chemical inhibition of both glutaminase and CPT1 decreased cell proliferation and migration of CB-839-resistant cells compared with single inhibition of each enzyme. We propose that dual targeting of glutaminase and CPT1 activities may have therapeutic relevance for managing CB-839-resistant tumors.
Assuntos
Benzenoacetamidas/farmacologia , Carnitina O-Palmitoiltransferase/antagonistas & inibidores , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Glutaminase/antagonistas & inibidores , Glutamina/metabolismo , Tiadiazóis/farmacologia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Feminino , Humanos , Oxirredução , Neoplasias de Mama Triplo Negativas/enzimologia , Neoplasias de Mama Triplo Negativas/patologia , Células Tumorais CultivadasRESUMO
The main κ opioid receptors (κORs) subtypes already described (κ1ORs and κ2ORs) are expressed in brain regions involved in aversive memory consolidation, including the dorsal hippocampus (DH). However, the role of DH κORs in consolidation of aversive memories with varied intensity and specificity is still uncertain. The present study aimed to investigate this question using pharmacological agents in rats subjected to a weak, moderate or strong contextual aversive conditioning (CAC) protocol. Antagonizing DH κORs with nor-binaltorphimine (nor-BNI), immediately after, but not 6â¯h later, a moderate CAC leads to intensified freezing behavior in the re-exposure to the paired context. Thus, indicating that DH κORs have an inhibitory role in the consolidation of an aversive memory. Increased DH κORs expression 1â¯h and 3â¯h after the moderate CAC was also observed. This up-regulation was absent in animals only exposed to the shock or to the context, indicating that this phenomenon requires a shock-context pairing to occur. Intra-DH nor-BNI infusion induced no changes following a weak CAC, but it was able to potentiate the expression of freezing behavior in novel and unpaired context after a strong CAC, indicating that DH κORs also modulate the consolidation of a more intense and generalized memory. Moreover, infusing the κ2ORs agonist GR 89696, but not the κ1ORs agonist U-69593, into the DH reduced the conditioned freezing expression. Nor-BNI pretreatment in a sub-effective dose prevented the κ2ORs agonist effects. Altogether, the present findings provide convergent evidence that κORs activation negatively modulates contextual aversive memory consolidation in rat dorsal hippocampus.
Assuntos
Aprendizagem da Esquiva/fisiologia , Hipocampo/metabolismo , Consolidação da Memória/fisiologia , Receptores Opioides kappa/metabolismo , Analgésicos Opioides/farmacologia , Animais , Associação , Aprendizagem da Esquiva/efeitos dos fármacos , Benzenoacetamidas/farmacologia , Condicionamento Psicológico/efeitos dos fármacos , Condicionamento Psicológico/fisiologia , Eletrochoque , Reação de Congelamento Cataléptica/efeitos dos fármacos , Reação de Congelamento Cataléptica/fisiologia , Hipocampo/efeitos dos fármacos , Masculino , Consolidação da Memória/efeitos dos fármacos , Naltrexona/análogos & derivados , Naltrexona/farmacologia , Antagonistas de Entorpecentes/farmacologia , Piperazinas/farmacologia , Psicotrópicos/farmacologia , Pirrolidinas/farmacologia , Distribuição Aleatória , Ratos Wistar , Receptores Opioides kappa/agonistas , Receptores Opioides kappa/antagonistas & inibidoresRESUMO
Acute myeloid leukemia (AML) is a blood cancer that is poorly responsive to conventional cytotoxic chemotherapy and a diagnosis of AML is usually fatal. More effective and better-tolerated therapies for AML are desperately needed. Activating mutations in FMS-like tyrosine kinase 3 (FLT3) are one of the most frequently observed genetic defects in AML. FLT3 inhibitors have shown impressive anti-leukemic activity in clinical trials; however, sustained remissions using these inhibitors as monotherapy have not been achieved. Our previous studies have implicated impaired glutamine metabolism in response to FLT3 inhibitors as a dominant factor causing AML cell death. In this study, we have employed metabolic flux analysis to examine the effects of FLT3 inhibition on glutamine utilization in FLT3-mutated AML cells using stable isotope tracers. We found that the FLT3 inhibitor AC220 inhibited glutamine flux into the antioxidant factor glutathione profoundly due to defective glutamine import. We also found that the glutaminase inhibitor CB-839 similarly impaired glutathione production by effectively blocking flux of glutamine into glutamate. Moreover, the combination of AC220 with CB-839 synergized to deplete glutathione, induce mitochondrial reactive oxygen species, and cause loss of viability through apoptotic cell death. In vivo, glutaminase inhibition with CB-839 facilitated leukemic cell elimination by AC220 and improved survival significantly in a patient-derived xenograft AML mouse model. Therefore, targeting glutaminase in combination with FLT3 may represent an effective therapeutic strategy for improving treatment of FLT3-mutated AML.
Assuntos
Benzenoacetamidas/farmacologia , Benzotiazóis/farmacologia , Glutaminase , Leucemia Mieloide Aguda , Compostos de Fenilureia/farmacologia , Tiadiazóis/farmacologia , Tirosina Quinase 3 Semelhante a fms , Animais , Linhagem Celular Tumoral , Feminino , Ácido Glutâmico/genética , Ácido Glutâmico/metabolismo , Glutaminase/antagonistas & inibidores , Glutaminase/genética , Glutaminase/metabolismo , Glutamina/genética , Glutamina/metabolismo , Humanos , Leucemia Mieloide Aguda/tratamento farmacológico , Leucemia Mieloide Aguda/enzimologia , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patologia , Camundongos , Camundongos Endogâmicos NOD , Camundongos Transgênicos , Ensaios Antitumorais Modelo de Xenoenxerto , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Tirosina Quinase 3 Semelhante a fms/genética , Tirosina Quinase 3 Semelhante a fms/metabolismoRESUMO
A1899 is a potent and selective inhibitor of the two-pore domain potassium (K2P) channel TASK-1. It was previously reported that A1899 acts as an open-channel blocker and binds to residues of the P1 and P2 regions, the M2 and M4 segments, and the halothane response element. The recently described crystal structures of K2P channels together with the newly identified side fenestrations indicate that residues relevant for TASK-1 inhibition are not purely facing the central cavity as initially proposed. Accordingly, the TASK-1 binding site and the mechanism of inhibition might need a re-evaluation. We have used TASK-1 homology models based on recently crystallized K2P channels and molecular dynamics simulation to demonstrate that the highly potent TASK-1 blocker A1899 requires binding to residues located in the side fenestrations. Unexpectedly, most of the previously described residues that interfere with TASK-1 blockade by A1899 project their side chains toward the fenestration lumina, underlining the relevance of these structures for drug binding in K2P channels. Despite its hydrophobicity, A1899 does not seem to use the fenestrations to gain access to the central cavity from the lipid bilayer. In contrast, binding of A1899 to residues of the side fenestrations might provide a physical "anchor", reflecting an energetically favorable binding mode that after pore occlusion stabilizes the closed state of the channels.
Assuntos
Benzamidas/farmacologia , Benzenoacetamidas/farmacologia , Simulação de Dinâmica Molecular , Proteínas do Tecido Nervoso/antagonistas & inibidores , Canais de Potássio de Domínios Poros em Tandem/antagonistas & inibidores , Animais , Benzamidas/química , Benzenoacetamidas/química , Sítios de Ligação , Humanos , Interações Hidrofóbicas e Hidrofílicas , Proteínas do Tecido Nervoso/química , Proteínas do Tecido Nervoso/metabolismo , Canais de Potássio de Domínios Poros em Tandem/química , Canais de Potássio de Domínios Poros em Tandem/metabolismoRESUMO
The effects after the acute activation of the kappa opioid receptor (KOR) can be distinguished from the effect after repeated administration of KOR agonist. Here, we report the effect of repeated administration of U69593 during abstinence after amphetamine-induced locomotor sensitization. Rats were injected once daily with amphetamine for five consecutive days. From day 6 to 9, rats that developed locomotor sensitization, received once daily injection of U69593 or vehicle. On day 10, all rats were injected with a challenging dose of amphetamine and locomotor activity was measured to assess the expression of sensitization. Microdialysis studies were carried out to assess dopamine extracellular levels in NAc. Rats that develop and express horizontal locomotor sensitization to amphetamine show increased dopamine release in the NAc induced by high K(+). The repeated treatment with U69593 reverses the sensitized depolarization-stimulated dopamine release in the NAc, but not the expression of locomotor sensitization induced by amphetamine. Thus, repeated activation of KORs during early amphetamine withdrawal dissociates the behavioral responses and the neurochemical responses that accompany the expression of sensitization to amphetamine.
Assuntos
Anfetaminas/administração & dosagem , Benzenoacetamidas/farmacologia , Dopamina/metabolismo , Locomoção/efeitos dos fármacos , Núcleo Accumbens/efeitos dos fármacos , Potássio/metabolismo , Pirrolidinas/farmacologia , Receptores Opioides kappa/agonistas , Animais , Masculino , Microdiálise , Núcleo Accumbens/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
Acute activation of κ-opioid receptors (KOR) decreases dopamine (DA) extracellular levels in both the medial prefrontal cortex (mPFC) and the nucleus accumbens (NAc). Also, the acute activation of KOR prevents alterations in behavior and neurochemistry occurring after repeated use of psychostimulants. Opposing to the acute effects, repeated administration of the KOR agonist, U-6593, potentiates both high-potassium and amphetamine induced DA release in the NAc, suggesting that repeated activation of KOR sensitizes mesolimbic dopaminergic neurotransmission. This study investigated the effect of repeated treatment with U-69593 on basal and stimulated DA and serotonin (5HT) extracellular levels in the rat mPFC. Rats were injected once daily with U-69593 (0.16-0.32 mg/kg) or vehicle for 4 days. One day after the last injection, microdialysis experiments assessing DA and 5HT extracellular levels in mPFC were conduced. The repeated treatment with U-69593 significantly augmented potassium-stimulated DA extracellular levels, without affecting potassium-stimulated 5HT extracellular levels, suggesting an increase in DA releasability.
Assuntos
Benzenoacetamidas/farmacologia , Dopamina/metabolismo , Potássio/farmacologia , Córtex Pré-Frontal/efeitos dos fármacos , Córtex Pré-Frontal/metabolismo , Pirrolidinas/farmacologia , Receptores Opioides kappa/agonistas , Analgésicos/farmacologia , Animais , Esquema de Medicação , Masculino , Potássio/metabolismo , Ratos , Ratos Sprague-DawleyRESUMO
Pulmonary fibrosis is characterized by chronic inflammation and excessive collagen deposition. Neutrophils are thought to be involved in the pathogenesis of lung fibrosis. We hypothesized that CXCR2-mediated neutrophil recruitment is essential for the cascade of events leading to bleomycin-induced pulmonary fibrosis. CXCL1/KC was detected as early as 6 hours after bleomycin instillation and returned to basal levels after Day 8. Neutrophils were detected in bronchoalveolar lavage and interstitium from 12 hours and peaked at Day 8 after instillation. Treatment with the CXCR2 receptor antagonist, DF2162, reduced airway neutrophil transmigration but led to an increase of neutrophils in lung parenchyma. There was a significant reduction in IL-13, IL-10, CCL5/RANTES, and active transforming growth factor (TGF)-beta(1) levels, but not on IFN-gamma and total TGF-beta(1,) and enhanced granulocyte macrophage-colony-stimulating factor production in DF2162-treated animals. Notably, treatment with the CXCR2 antagonist led to an improvement of the lung pathology and reduced collagen deposition. Using a therapeutic schedule, DF2162 administered from Days 8 to 16 after bleomycin reduced pulmonary fibrosis and levels of active TGF-beta(1) and IL-13. DF2162 treatment reduced bleomycin-induced expression of von Willebrand Factor, a marker of angiogenesis, in the lung. In vitro, DF2162 reduced the angiogenic activity of IL-8 on human umbilical vein endothelial cells. In conclusion, we show that CXCR2 plays an important role in mediating fibrosis after bleomycin instillation. The compound blocks angiogenesis and the production of pro-angiogenic cytokines, and decreases IL-8-induced endothelial cell activation. An effect on neutrophils does not appear to account for the major effects of the blockade of CXCR2 in the system.
Assuntos
Pneumonia/complicações , Pneumonia/metabolismo , Fibrose Pulmonar/complicações , Fibrose Pulmonar/metabolismo , Receptores de Interleucina-8B/metabolismo , Animais , Benzenoacetamidas/administração & dosagem , Benzenoacetamidas/farmacologia , Bleomicina , Líquido da Lavagem Broncoalveolar , Movimento Celular/efeitos dos fármacos , Quimiocinas/biossíntese , Relação Dose-Resposta a Droga , Humanos , Cinética , Masculino , Mesilatos/administração & dosagem , Mesilatos/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Neovascularização Patológica/metabolismo , Neutrófilos/citologia , Neutrófilos/efeitos dos fármacos , Pneumonia/induzido quimicamente , Pneumonia/patologia , Fibrose Pulmonar/induzido quimicamente , Fibrose Pulmonar/patologia , Receptores de Interleucina-8B/antagonistas & inibidores , Fatores de TempoRESUMO
OBJECTIVE: The chemokine receptors CXCR1 and CXCR2 play a role in mediating neutrophil recruitment and neutrophil-dependent injury in several models of inflammation. We undertook this study to investigate the role of these receptors in mediating neutrophil adhesion, subsequent migration, and neutrophil-dependent hypernociception in a murine model of monarticular antigen-induced arthritis (AIA). METHODS: AIA was induced by administration of antigen into the knee joint of previously immunized mice. Intravital microscopy studies were performed to assess leukocyte rolling and adhesion. Mechanical hypernociception was investigated using an electronic pressure meter. Neutrophil accumulation in the tissue was measured by counting neutrophils in the synovial cavity and assaying myeloperoxidase activity. Levels of tumor necrosis factor alpha (TNFalpha) and the chemokines CXCL1 and CXCL2 were quantified by enzyme-linked immunosorbent assay. Histologic analysis was performed to evaluate the severity of arthritis and leukocyte infiltration. RESULTS: Antigen challenge in immunized mice induced production of TNFalpha, CXCL1, and CXCL2 and also resulted in neutrophil recruitment, leukocyte rolling and adhesion, and hypernociception. Treatment with reparixin or DF2162 (allosteric inhibitors of CXCR1/CXCR2) decreased neutrophil recruitment, an effect that was associated with marked inhibition of neutrophil adhesion. Drug treatment also inhibited TNFalpha production, hypernociception, and the overall severity of the disease in the tissue. CONCLUSION: Blockade of CXCR1/CXCR2 receptors inhibits neutrophil recruitment by inhibiting the adhesion of neutrophils to synovial microvessels. As a consequence, there is decreased local cytokine production and reduced hypernociception, as well as ameloriation of overall disease in the tissue. These studies suggest a potential therapeutic role for the modulation of CXCR1/CXCR2 receptor signaling in the treatment of arthritis.