RESUMO
Activation of the Ras signaling pathway promotes the growth of malignant human glioblastoma multiforme (GBM). Mutations in Ras are rare in GBM, elevated levels of activated Ras are prevalently observed in GBM. However, the potential mechanism of how Ras is activated in GBM remains unclear. In this study, we screened a new interacted protein of Ras, PHLDA1. Our findings confirmed that PHLDA1 acted as an oncogene and promoted glioma progression and recurrence. We demonstrated that PHLDA1 was upregulated in GBM tissues and cells. PHLDA1 overexpression promoted cell proliferation and tumor growth. In terms of mechanism, PHLDA1 promoted cell proliferation by regulating Ras/Raf/Mek/Erk signaling pathway. Moreover, Src promotes GTPase activity of Ras via tyrosine 32 phosphorylation. PHLDA1 and Src competed for binding with Ras, inhibiting Ras phosphorylation by Src and rescuing Ras activity. This study may provide a new idea of the molecular mechanism underlying glioma progression and a novel potential therapeutic target for comprehensive glioblastoma treatment.
Assuntos
Glioblastoma , Proliferação de Células , GTP Fosfo-Hidrolases , Glioblastoma/patologia , Humanos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Fatores de Transcrição , TirosinaRESUMO
During transformation, myelodysplastic syndromes (MDS) are characterized by reducing apoptosis of bone marrow (BM) precursors. Mouse models of high risk (HR)-MDS and acute myelogenous leukemia (AML) post-MDS using mutant NRAS and overexpression of human BCL-2, known to be poor prognostic indicators of the human diseases, were created. We have reported the efficacy of the BCL-2 inhibitor, ABT-737, on the AML post-MDS model; here, we report that this BCL-2 inhibitor also significantly extended survival of the HR-MDS mouse model, with reductions of BM blasts and lineage negative/Sca1+/KIT+ (LSK) cells. Secondary transplants showed increased survival in treated compared to untreated mice. Unlike the AML model, BCL-2 expression and RAS activity decreased following treatment and the RAS:BCL-2 complex remained in the plasma membrane. Exon-specific gene expression profiling (GEP) of HR-MDS mice showed 1952 differentially regulated genes upon treatment, including genes important for the regulation of stem cells, differentiation, proliferation, oxidative phosphorylation, mitochondrial function, and apoptosis; relevant in human disease. Spliceosome genes, found to be abnormal in MDS patients and downregulated in our HR-MDS model, such as Rsrc1 and Wbp4, were upregulated by the treatment, as were genes involved in epigenetic regulation, such as DNMT3A and B, upregulated upon disease progression and downregulated upon treatment.
Assuntos
Compostos de Bifenilo/administração & dosagem , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Síndromes Mielodisplásicas/tratamento farmacológico , Síndromes Mielodisplásicas/metabolismo , Nitrofenóis/administração & dosagem , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Transdução de Sinais/efeitos dos fármacos , Células-Tronco/metabolismo , Sulfonamidas/administração & dosagem , Animais , Apoptose/efeitos dos fármacos , Medula Óssea/metabolismo , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Perfilação da Expressão Gênica/métodos , Estimativa de Kaplan-Meier , Camundongos , Camundongos Transgênicos , Proteínas Monoméricas de Ligação ao GTP/genética , Síndromes Mielodisplásicas/mortalidade , Piperazinas/administração & dosagem , Proteínas Proto-Oncogênicas c-bcl-2/genética , Células-Tronco/efeitos dos fármacos , Transcriptoma/efeitos dos fármacosRESUMO
Phospholipase D (PLD), a major source of lipid second messengers (phosphatidic acid, diglycerides) in many cell types, is tightly regulated by protein kinases, but only a few of them have been identified. We show here that protein kinase B (AKT) is a novel major signaling effector of PLD activity induced by the formylpeptide f-Met-Leu-Phe (fMLP) in human neutrophil-like HL-60 cells (dHL-60 cells). AKT inhibition with the selective antagonist AKTib1/2 almost completely prevented fMLP-mediated activity of PLD, its upstream effector ERK1/2, but not p38 MAPK. Immunoprecipitation studies show that phosphorylated AKT, ERK, and PLD2 form a complex induced by fMLP, which can be prevented by AKTib1/2. In cell-free systems, AKT1 stimulated PLD activity via activation of ERK. AKT1 actually phosphorylated ERK2 as a substrate (K(m) 1 µm). Blocking AKT activation with AKTib1/2 also prevented fMLP- but not phorbol 12-myristate 13-acetate-mediated NADPH oxidase activation (respiratory burst, RB) of dHL-60 cells. Impaired RB was associated with defective membrane translocation of NADPH oxidase components p67(phox) and p47(phox), ERK, AKT1, AKT2, but not AKT3. Depletion of AKT1 or AKT2 with antisense oligonucleotides further indicates a partial contribution of both isoforms in fMLP-induced activation of ERK, PLD, and RB, with a predominant role of AKT1. Thus, formylpeptides induce sequential activation of AKT, ERK1/2, and PLD, which represents a novel signaling pathway. A major primarily role of this AKT signaling pathway also emerges in membrane recruitment of NOX2 components p47(phox), p67(phox), and ERK, which may contribute to assembly and activation of the RB motor system, NADPH oxidase.
Assuntos
Células HL-60 , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , N-Formilmetionina Leucil-Fenilalanina/farmacologia , Fosfolipase D/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Explosão Respiratória/fisiologia , Ativação Enzimática , Células HL-60/efeitos dos fármacos , Células HL-60/fisiologia , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , MAP Quinase Quinase Quinases/metabolismo , NADPH Oxidases/metabolismo , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Transdução de Sinais/efeitos dos fármacosRESUMO
Previous reports from this laboratory and others demonstrated NO-mediated biphasic modulation of NADPH oxidase and attenuation of neutrophil reactive oxygen species generation, whereas recently we reported augmentation in DCF fluorescence following NO treatment. These discrepancies seem to be due to utilization of different probes/methods to assess effect of NO on reactive oxygen and nitrogen species (ROS/RNS, reactive species) generation. This study aims to look into this and evaluate NO-mediated enzymatic reactive species formation by using multiple probes, human neutrophils/HL60 cells and various interventions. Addition of NO donor, SNP or SNAP (100 nM-1 mM) to PMNs suspension, exhibited a concentration- and time-dependent augmentation in DCF fluorescence, but reduced DHE fluorescence. Collective generation of reactive species was confirmed by enhanced DMPO-nitrone adduct, dityrosine and rhodamine-123 and quenching of scopoletin. NO also enhanced bacterial killing, without altering phagocytosis. Addition of NO to HL-60 cells lacking functional NADPH oxidase enhanced reactive species formation, indicating importance of other enzyme(s) too. NO-dependent ROS/RNS generation was substantially reduced by NADPH oxidase inhibitor (DPI), MPO inhibitor (ABAH), or NOS inhibitor (7-NI). However, 7-NI reduced MPO activity, warranting reappraisal of those reports, which implied NOS in reactive species formation. The results obtained demonstrated NO-mediated reactive species augmentation in human PMNs. Furthermore, superoxide scavenging by NO seems to be the key process in the decrease of DHE fluorescence and suggest usefulness of DCF as the most appropriate probe to measure the NO-mediated modulation of reactive oxygen species in particular in various pathological situations.
Assuntos
Citometria de Fluxo/métodos , Neutrófilos/efeitos dos fármacos , Óxido Nítrico/farmacologia , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Quimioterapia Combinada , Fluoresceínas/química , Fluorescência , Células HL-60 , Humanos , Neutrófilos/metabolismo , Doadores de Óxido Nítrico/farmacologia , Nitroprussiato/farmacologia , Fagocitose/efeitos dos fármacos , S-Nitroso-N-Acetilpenicilamina/farmacologiaRESUMO
High availability of NO, oxidative stress and neutrophil extracellular trap (NETs) contents are often noticed at the site of inflammation/infection. Studies from this lab and others have reported NO mediated free radical generation from neutrophils; role of NO in NETs formation however remains undefined so far. The present study was therefore undertaken to explore the effect of NO donors on NET release from human neutrophils (PMNs), using confocal/scanning microscopy, measuring the extracellular DNA content and NET-bound elastase activity. Addition of NO donors (SNAP and SNP) to adhered PMNs led to a time and concentration dependent NETs release, which was blocked by N-acetyl cysteine, suggesting involvement of free radicals in NETs formation. Free radical formation by NO donors was assessed by using DCF-DA, DMPO-nitrone antibody and by p47 phox migration to the neutrophils membrane. NO mediated formation of free radicals and NETs was significantly reduced by the pretreatment of neutrophils with diphenyleneiodonium (DPI), a NADPH-oxidase inhibitor and 4-aminobenzoic acid hydrazide (ABAH), a myeloperoxidase inhibitor, suggesting role of enzymatic free radical generation by NO donors. We thus demonstrate that NO by augmenting free radical formation in human neutrophils mediates NETs release.
Assuntos
Espaço Extracelular/efeitos dos fármacos , Radicais Livres/metabolismo , Neutrófilos/efeitos dos fármacos , Doadores de Óxido Nítrico/farmacologia , Nitroprussiato/farmacologia , S-Nitroso-N-Acetilpenicilamina/farmacologia , Relação Dose-Resposta a Droga , Espaço Extracelular/metabolismo , Humanos , Neutrófilos/metabolismo , Relação Estrutura-Atividade , Fatores de TempoRESUMO
The development of genetic engineering in the 1970s marked a new frontier in genome-editing technology. Gene-editing technologies have provided a plethora of benefits to the life sciences. The clustered regularly interspaced short palindromic repeats/CRISPR associated protein 9 (CRISPR/ Cas9) system is a versatile technology that provides the ability to add or remove DNA in the genome in a sequence-specific manner. Serious efforts are underway to improve the efficiency of CRISPR/Cas9 targeting and thus reduce off-target effects. Currently, various applications of CRISPR/Cas9 are used in cancer biology and oncology to perform robust site-specific gene editing, thereby becoming more useful for biological and clinical applications. Many variants and applications of CRISPR/Cas9 are being rapidly developed. Experimental approaches that are based on CRISPR technology have created a very promising tool that is inexpensive and simple for developing effective cancer therapeutics. This review discusses diverse applications of CRISPR-based gene-editing tools in oncology and potential future cancer therapies.
RESUMO
We have previously shown that a specific promyelocytic leukemia-retinoic acid receptor alpha (PML-RARA) DNA vaccine combined with all-trans retinoic acid (ATRA) increases the number of long term survivors with enhanced immune responses in a mouse model of acute promyelocytic leukemia (APL). This study reports the efficacy of a non-specific DNA vaccine, pVAX14Flipper (pVAX14), in both APL and high risk myelodysplastic syndrome (HR-MDS) models. PVAX14 is comprised of novel immunogenic DNA sequences inserted into the pVAX1 therapeutic plasmid. APL mice treated with pVAX14 combined with ATRA had increased survival comparable to that obtained with a specific PML-RARA vaccine. Moreover, the survival advantage correlated with decreased PML-RARA transcript levels and increase in anti-RARA antibody production. In HR-MDS mice, pVAX14 significantly improved survival and reduced biomarkers of leukemic transformation such as phosphorylated mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) 1. In both preclinical models, pVAX14 vaccine significantly increased interferon gamma (IFNγ) production, memory T-cells (memT), reduced the number of colony forming units (CFU) and increased expression of the adapter molecule signalling to NF-κB, MyD88. These results demonstrate the adjuvant properties of pVAX14 providing thus new approaches to improve clinical outcome in two different models of myeloid malignancies, which may have potential for a broader applicability in other cancers.
Assuntos
Adjuvantes Imunológicos/farmacologia , Vacinas Anticâncer/farmacologia , Leucemia Promielocítica Aguda/tratamento farmacológico , Síndromes Mielodisplásicas/tratamento farmacológico , Neoplasias Experimentais/tratamento farmacológico , Tretinoína/farmacologia , Vacinas de DNA/farmacologia , Animais , Anticorpos/sangue , Sequência de Bases , Vacinas Anticâncer/imunologia , Regulação Neoplásica da Expressão Gênica , Genes ras , Memória Imunológica/efeitos dos fármacos , Interferon gama/imunologia , Interferon gama/metabolismo , Leucemia Promielocítica Aguda/genética , Leucemia Promielocítica Aguda/imunologia , Leucemia Promielocítica Aguda/metabolismo , Leucemia Promielocítica Aguda/patologia , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Linfócitos do Interstício Tumoral/imunologia , Linfócitos do Interstício Tumoral/metabolismo , Camundongos Transgênicos , Dados de Sequência Molecular , Síndromes Mielodisplásicas/genética , Síndromes Mielodisplásicas/imunologia , Síndromes Mielodisplásicas/metabolismo , Síndromes Mielodisplásicas/patologia , Neoplasias Experimentais/genética , Neoplasias Experimentais/imunologia , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Receptores do Ácido Retinoico/genética , Receptores do Ácido Retinoico/metabolismo , Receptor alfa de Ácido Retinoico , Transdução de Sinais/efeitos dos fármacos , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Linfócitos T/metabolismo , Fatores de Tempo , Carga Tumoral/efeitos dos fármacos , Vacinação , Vacinas de DNA/imunologiaRESUMO
In the present study, the role of ROS and RNS in activation of inflammatory response and associated molecular events during apoptosis of polymorphonuclear leucocytes (PMNs) in patients from an outbreak of argemone oil (AO) poisoning leading to epidemic dropsy in Lucknow, India was undertaken. It was observed that generation of superoxide radical, nitrite formation and phagocytosis (103-429%) were significantly increased in PMNs of dropsy patients. Furthermore, activities of superoxide dismutase and glutathione peroxidase (GPx) (47-79%) were found to be increased while that of catalase and glutathione reductase (GR) (56-57%) were decreased. Lipid and protein oxidation, nitrotyrosine formation and 8-hydroxydeoxyguanosine (8-OHdG) excretion were significantly enhanced with concomitant depletion of GSH levels (67%) in dropsy patients. In addition, significant elevation of IL-6, IL-8 and TNF-alpha (68-406%) in plasma was observed. Apoptosis was enhanced (1.5 folds) with increased (2.0-3.6 folds) caspases 3, 8 and 9 activities along with DNA fragmentation (119%). The results suggest that generation of ROS and RNS along with enhancement of secretion of inflammatory mediators leading to DNA damage followed by apoptosis may have an effect on immune system, which in turn may be responsible for histopathological changes in target organs of dropsy patients.
Assuntos
Apoptose , Mediadores da Inflamação/metabolismo , Neutrófilos/efeitos dos fármacos , Óleos de Plantas/intoxicação , Catalase/metabolismo , Dano ao DNA , Edema/induzido quimicamente , Edema/metabolismo , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Glutationa Redutase/metabolismo , Humanos , Interleucina-6/sangue , Interleucina-8/sangue , Peroxidação de Lipídeos , Neutrófilos/imunologia , Neutrófilos/metabolismo , Carbonilação Proteica , Espécies Reativas de Nitrogênio/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo , Fator de Necrose Tumoral alfa/sangueRESUMO
The present study investigated the effect of various ion (H+ and K+) channel modulators on nitric oxide (NO) donors (SNP and SNAP) induced free radical generation and on neutrophil membrane potential. Free radical generation was assessed by DCDHF-DA, using flow cytometry, while membrane potential was measured by a fluorescent dye, DiO-C5-(3). Neutrophil suspension in high potassium containing medium or following addition of NO donors (SNP, SNAP) to the neutrophil suspension led to free radical generation and membrane depolarization. DPI (a dual inhibitor of NADPH-oxidase and NOS), ABAH (MPO inhibitor) and BAPTA-AM (calcium chelator) significantly reduced 80 mM KCl or NO mediated free radical generation. Modulators of large (NS1619), intermediate (Chlorzoxazone) and small conductance (Apamin, chlorzoxazone) calcium activated K+ channels (TBA), voltage activated K+ channels (Kv) (4AP, 8Br-cGMP), ATP sensitive K+ channels (K(ATP)) (Glybenclamide, pinacidil), Na+,K+-ATPase (Ouabain) and Na+/H+ exchanger (NHE, Amiloride) altered NO-induced neutrophil free radical generation response and membrane polarity. The results obtained thus suggest an association between rat neutrophil membrane depolarization and NO-dependent free radical generation.