RESUMEN
Type I interferons (IFNs) induce expression of multiple genes that control innate immune responses to invoke both antiviral and antineoplastic activities. Transcription of these interferon-stimulated genes (ISGs) occurs upon activation of the canonical Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathways. Phosphorylation and acetylation are both events crucial to tightly regulate expression of ISGs. Here, using mouse embryonic fibroblasts and an array of biochemical methods including immunoblotting and kinase assays, we show that sirtuin 2 (SIRT2), a member of the NAD-dependent protein deacetylase family, is involved in type I IFN signaling. We found that SIRT2 deacetylates cyclin-dependent kinase 9 (CDK9) in a type I IFN-dependent manner and that the CDK9 deacetylation is essential for STAT1 phosphorylation at Ser-727. We also found that SIRT2 is subsequently required for the transcription of ISGs and for IFN-driven antiproliferative responses in both normal and malignant cells. These findings establish the existence of a previously unreported signaling pathway whose function is essential for the control of JAK-STAT signaling and the regulation of IFN responses. Our findings suggest that targeting sirtuin activities may offer an avenue in the development of therapies for managing immune-related diseases and cancer.
Asunto(s)
Quinasa 9 Dependiente de la Ciclina/metabolismo , Interferón Tipo I/metabolismo , Factor de Transcripción STAT1/metabolismo , Transducción de Señal , Sirtuina 2/metabolismo , Acetilación , Animales , Quinasa 9 Dependiente de la Ciclina/genética , Humanos , Interferón Tipo I/genética , Ratones , Ratones Noqueados , Fosforilación , Factor de Transcripción STAT1/genética , Sirtuina 2/genética , Transcripción Genética , Células U937RESUMEN
The precise signaling mechanisms by which type II IFN receptors control expression of unique genes to induce biological responses remain to be established. We provide evidence that Sin1, a known element of the mammalian target of rapamycin complex 2 (mTORC2), is required for IFNγ-induced phosphorylation and activation of AKT and that such activation mediates downstream regulation of mTORC1 and its effectors. These events play important roles in the assembly of the eukaryotic translation initiation factor 4F (eIF4F) and mRNA translation of IFN-stimulated genes. Interestingly, IFNγ-induced tyrosine phosphorylation of STAT1 is reduced in cells with targeted disruption of Sin1, leading to decreased transcription of several IFNγ-inducible genes in an mTORC2-independent manner. Additionally, our studies establish that Sin1 is essential for generation of type II IFN-dependent antiviral effects and antiproliferative responses in normal and malignant hematopoiesis. Together, our findings establish an important role for Sin1 in both transcription and translation of IFN-stimulated genes and type II IFN-mediated biological responses, involving both mTORC2-dependent and -independent functions.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/inmunología , Proteínas Portadoras/inmunología , Interferón gamma/inmunología , Animales , Línea Celular , Humanos , Inmunidad Innata , Ratones , Fosforilación , Proteínas Proto-Oncogénicas c-akt/química , Proteínas Proto-Oncogénicas c-akt/inmunología , Factor de Transcripción STAT1/química , Factor de Transcripción STAT1/inmunología , Transducción de SeñalRESUMEN
Mitogen-activated protein kinase interacting protein kinases (Mnks) play important roles in the development and progression of acute myeloid leukemia (AML) by regulating eukaryotic translation initiation factor 4E (eIF4E) activation. Inhibiting Mnk1/2-induced phosphorylation of eIF4E may represent a unique approach for the treatment of AML. We provide evidence for antileukemic effects of merestinib, an orally bioavailable multikinase inhibitor with suppressive effects on Mnk activity. Our studies show that merestinib effectively blocks eIF4E phosphorylation in AML cells and suppresses primitive leukemic progenitors from AML patients in vitro and in an AML xenograft model in vivo. Our findings provide evidence for potent preclinical antileukemic properties of merestinib and support its clinical development for the treatment of patients with AML.
Asunto(s)
Adenosina Trifosfatasas/antagonistas & inhibidores , Proteínas de Transporte de Catión/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Leucemia Mieloide Aguda/tratamiento farmacológico , Proteínas de Neoplasias/antagonistas & inhibidores , Adenosina Trifosfatasas/metabolismo , Animales , Proteínas de Transporte de Catión/metabolismo , Línea Celular Tumoral , ATPasas Transportadoras de Cobre , Factor 4E Eucariótico de Iniciación/metabolismo , Humanos , Leucemia Mieloide Aguda/enzimología , Ratones , Proteínas de Neoplasias/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
We provide evidence for a unique pathway engaged by the type II IFN receptor, involving mTORC2/AKT-mediated downstream regulation of mTORC1 and effectors. These events are required for formation of the eukaryotic translation initiation factor 4F complex (eIF4F) and initiation of mRNA translation of type II interferon-stimulated genes. Our studies establish that Rictor is essential for the generation of type II IFN-dependent antiviral and antiproliferative responses and that it controls the generation of type II IFN-suppressive effects on normal and malignant hematopoiesis. Together, our findings establish a central role for mTORC2 in IFNγ signaling and type II IFN responses.
Asunto(s)
Proteínas Portadoras/metabolismo , Factor 4F Eucariótico de Iniciación/metabolismo , Interferón gamma/metabolismo , Complejos Multiproteicos/metabolismo , Receptores de Interferón/metabolismo , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Animales , Antivirales/química , Antivirales/metabolismo , Quimiocina CXCL10/metabolismo , Fibroblastos/metabolismo , Regulación de la Expresión Génica , Hematopoyesis , Células Madre Hematopoyéticas/citología , Humanos , Subunidad gamma del Factor 3 de Genes Estimulados por el Interferón/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina , Diana Mecanicista del Complejo 2 de la Rapamicina , Ratones , Ratones Noqueados , Fosforilación , Polirribosomas/metabolismo , Biosíntesis de Proteínas , Proteína Asociada al mTOR Insensible a la Rapamicina , Células U937RESUMEN
Dysregulation of mRNA translation leads to aberrant activation of cellular pathways that promote expansion and survival of leukemic clones. A key element of the initiation translation complex is eIF4E (eukaryotic translation initiation factor 4E). The mitogen-activated protein kinase (MAPK) and mammalian target of rapamycin (mTOR) pathways play important roles in the regulation of eIF4E expression and downstream functional outcomes. Mitogen-activated protein kinase interacting protein kinases (Mnks) control translation by phosphorylation of eIF4E, whereas the mTOR kinase phosphorylates/de-activates the eIF4E inhibitor, 4E-BP1, to release translational repression. Both pathways are often abnormally activated in leukemia cells and promote cell survival events by controlling expression of oncogenic proteins. Targeting these pathways may provide approaches to avoid aberrant proliferation and neoplastic transformation.
Asunto(s)
Factor 4E Eucariótico de Iniciación/metabolismo , Leucemia Mieloide Aguda/metabolismo , Proteínas de Neoplasias/metabolismo , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Animales , Factor 4E Eucariótico de Iniciación/genética , Humanos , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/patología , Ratones , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/genética , Inhibidores de Proteínas Quinasas/farmacología , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Serina-Treonina Quinasas TOR/genéticaRESUMEN
BACKGROUND: Genome-wide gene expression profiling allows for identification of genes involved in the defense response of the host against pathogens. As presented here, transcriptomic analysis and bioinformatics tools were applied in order to identify genes expressed in the mammary gland parenchyma of cows naturally infected with coagulase-positive and coagulase-negative Staphylococci. RESULTS: In cows infected with coagulase-positive Staphylococci, being in 1st or 2nd lactation, 1700 differentially expressed genes (DEGs) were identified. However, examination of the 3rd or 4th lactations revealed 2200 DEGs. Gene ontology functional classification showed the molecular functions of the DEGs overrepresented the activity of cytokines, chemokines, and their receptors. In cows infected with coagulase-negative Staphylococci, in the 1st or 2nd lactations 418 DEGs, while in the 3rd or 4th lactations, 1200 DEGs were identified that involved in molecular functions such as protein, calcium ion and lipid binding, chemokine activity, and protein homodimerization. Gene network analysis showed DEGs associated with inflammation, cell migration, and immune response to infection, development of cells and tissues, and humoral responses to infections caused by both types of Staphylococci. CONCLUSION: A coagulase-positive Staphylococci infection caused a markedly stronger host response than that of coagulase-negative, resulting in vastly increased DEGs. A significant increase in the expression of the FOS, TNF, and genes encoding the major histocompatibility complex proteins (MHC) was observed. It suggests these genes play a key role in the synchronization of the immune response of the cow's parenchyma against mastitis-causing bacteria. Moreover, the following genes that belong to several physiological pathways (KEGG pathways) were selected for further studies as candidate genes of mammary gland immune response for use in Marker Assisted Selection (MAS): chemokine signaling pathway (CCL2, CXCL5, HCK, CCR1), cell adhesion molecules (CAMs) pathway (BOLA-DQA2, BOLA-DQA1, F11R, ITGAL, CD86), antigen processing and presentation pathway (CD8A, PDIA3, LGMN, IFI30, HSPA1A), and NOD-like receptor signaling pathway (TNF, IL8, IL18, NFKBIA).
Asunto(s)
Glándulas Mamarias Animales/metabolismo , Mastitis Bovina/microbiología , Tejido Parenquimatoso/microbiología , Infecciones Estafilocócicas/genética , Animales , Bovinos , Coagulasa/metabolismo , Bases de Datos Genéticas , Femenino , Perfilación de la Expresión Génica/veterinaria , Mastitis Bovina/genética , Familia de Multigenes , Tejido Parenquimatoso/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa , Staphylococcus/enzimologíaRESUMEN
BACKGROUND: Mastitis is still considered to be the most economically important infectious disease in dairy cattle breeding. The immune response in mammary gland tissues could help in developing support strategies to combat this disease. The role of neutrophils and macrophages in the innate response of mammary gland is well known. However, the immune response in mammary gland tissues, including levels of antimicrobial peptide transcripts, has not been well recognized. Moreover, most studies are conducted in vitro, on cell cultures, or on artificially infected animals, with analysis being done within a several dozen hours after infection.The aim of the study was to examine the in vivo transcript levels of beta-defensin and cathelicidins genes in cow mammary gland secretory tissue (parenchyma) with the chronic, recurrent and incurable mammary gland inflammation induced by coagulase-positive or coagulase-negative Staphyloccoci vs. bacteria-free tissue. RESULTS: The mRNA of DEFB1, BNBD4, BNBD5, BNBD10 and LAP genes, but not of TAP gene, were detected in all investigated samples regardless of the animals' age and microbiological status of the mammary gland, but at different levels. The expression of most of the beta-defensin genes was shown to be much higher in tissues derived from udders infected with bacteria (CoPS or CoNS) than from bacteria-free udders, regardless of parity. Cathelicidins (CATH4, CATH5 and CATH6) showed expression patterns contrasting those of ß-defensins, with the highest expression in tissues derived from bacteria-free udders. CONCLUSION: Increased expression of genes encoding ß-defensins in the infected udder confirms their crucial role in the defense of the cow mammary gland against mastitis. On the other hand, the elevated cathelicidin transcripts in non-infected tissues indicate their role in the maintenance of healthy mammary tissues. The expression levels of investigated genes are likely to depend on the duration of the infection and type of bacteria.
Asunto(s)
Catelicidinas/metabolismo , Coagulasa/metabolismo , Regulación de la Expresión Génica/inmunología , Glándulas Mamarias Animales/metabolismo , Staphylococcus/enzimología , beta-Defensinas/metabolismo , Animales , Catelicidinas/genética , Bovinos , Coagulasa/genética , Femenino , Mastitis Bovina/metabolismo , Mastitis Bovina/microbiología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/veterinaria , beta-Defensinas/genéticaRESUMEN
This study examined liver transcriptomic profiles of cattle distinctly different in meat and milk production capacity. It was performed on bulls of two different genetic backgrounds: Herefords (H), a meat breed, and Holstein-Friesians (HF), a dairy breed. Using bovine long oligo-microarrays and qPCR, we identified 128 genes that are differentially expressed between the two breeds. In H bulls, we observed up-regulation of genes involved in fatty acid biosynthesis and lipid metabolism (CD36, CAT, HSD3B1, FABP1, ACAA1) and involved in insulin signaling (INSR, INSIG2, NR4A1) and down-regulation of genes involved in somatotropic axis signaling (IGF1, GHR, IGFBP3) as compared to HF. Transcriptome profiling of these two breeds allowed us to pinpoint the transcriptional differences between Holstein and Hereford bulls at hepatic level associated with changes in metabolism and postnatal growth.
Asunto(s)
Bovinos/genética , Hígado/metabolismo , Transcriptoma , Animales , Bovinos/crecimiento & desarrollo , Bovinos/metabolismo , Perfilación de la Expresión Génica , Masculino , ARN Mensajero/metabolismoRESUMEN
Interferons (IFNs) are cytokines with potent antineoplastic and antiviral properties. IFNα has significant clinical activity in the treatment of myeloproliferative neoplasms (MPN), but the precise mechanisms by which it acts are not well understood. Here, we demonstrate that chromatin assembly factor 1 subunit B (CHAF1B), an Unc-51-like kinase 1 (ULK1)-interactive protein in the nuclear compartment of malignant cells, is overexpressed in patients with MPN. Remarkably, targeted silencing of CHAF1B enhances transcription of IFNα-stimulated genes and promotes IFNα-dependent antineoplastic responses in primary MPN progenitor cells. Taken together, our findings indicate that CHAF1B is a promising newly identified therapeutic target in MPN and that CHAF1B inhibition in combination with IFNα therapy might offer a novel strategy for treating patients with MPN. Significance: Our findings raise the potential for clinical development of drugs targeting CHAF1B to enhance IFN antitumor responses in the treatment of patients with MPN and should have important clinical translational implications for the treatment of MPN and possibly in other malignancies.
Asunto(s)
Neoplasias de la Médula Ósea , Trastornos Mieloproliferativos , Neoplasias , Humanos , Trastornos Mieloproliferativos/tratamiento farmacológico , Interferón-alfa/farmacología , Factor 1 de Ensamblaje de la Cromatina/genéticaRESUMEN
Cathelicidins are small, cationic, antimicrobial peptides found in humans and other species, including farm animals (cattle, horses, pigs, sheep, goats, chickens, rabbits and in some species of fish). These proteolytically activated peptides are part of the innate immune system of many vertebrates. These peptides show a broad spectrum of antimicrobial activity against bacteria, enveloped viruses and fungi. Apart from exerting direct antimicrobial effects, cathelicidins can also trigger specific defense responses in the host. Their roles in various pathophysiological conditions have been studied in mice and humans, but there are limited information about their expression sites and activities in livestock. The aim of the present review is to summarize current information about these antimicrobial peptides in farm animals, highlighting peptide expression sites, activities, and future applications for human and veterinary medicine.
Asunto(s)
Catelicidinas/metabolismo , Secuencia de Aminoácidos , Animales , Catelicidinas/química , Catelicidinas/genética , Catelicidinas/farmacología , Variación Genética , Humanos , Datos de Secuencia MolecularRESUMEN
Interferons (IFNs) are key initiators and effectors of the immune response against malignant cells and also directly inhibit tumor growth. IFNα is highly effective in the treatment of myeloproliferative neoplasms (MPNs), but the mechanisms of action are unclear and it remains unknown why some patients respond to IFNα and others do not. Here, we identify and characterize a pathway involving PKCδ-dependent phosphorylation of ULK1 on serine residues 341 and 495, required for subsequent activation of p38 MAPK. We show that this pathway is essential for IFN-suppressive effects on primary malignant erythroid precursors from MPN patients, and that increased levels of ULK1 and p38 MAPK correlate with clinical response to IFNα therapy in these patients. We also demonstrate that IFNα treatment induces cleavage/activation of the ULK1-interacting ROCK1/2 proteins in vitro and in vivo, triggering a negative feedback loop that suppresses IFN responses. Overexpression of ROCK1/2 is seen in MPN patients and their genetic or pharmacological inhibition enhances IFN-anti-neoplastic responses in malignant erythroid precursors from MPN patients. These findings suggest the clinical potential of pharmacological inhibition of ROCK1/2 in combination with IFN-therapy for the treatment of MPNs.
Asunto(s)
Trastornos Mieloproliferativos , Neoplasias , Antivirales/uso terapéutico , Retroalimentación , Humanos , Interferón-alfa/farmacología , Interferón-alfa/uso terapéutico , Trastornos Mieloproliferativos/tratamiento farmacológico , Trastornos Mieloproliferativos/genética , Trastornos Mieloproliferativos/metabolismo , Neoplasias/tratamiento farmacológico , Transducción de Señal , Quinasas Asociadas a rho/metabolismoRESUMEN
The MAPK-interacting kinases 1 and 2 (MNK1/2) have generated increasing interest as therapeutic targets for acute myeloid leukemia (AML). We evaluated the therapeutic potential of the highly-selective MNK1/2 inhibitor Tomivosertib on AML cells. Tomivosertib was highly effective at blocking eIF4E phosphorylation on serine 209 in AML cells. Such inhibitory effects correlated with dose-dependent suppression of cellular viability and leukemic progenitor colony formation. Moreover, combination of Tomivosertib and Venetoclax resulted in synergistic anti-leukemic responses in AML cell lines. Mass spectrometry studies identified novel putative MNK1/2 interactors, while in parallel studies we demonstrated that MNK2 - RAPTOR - mTOR complexes are not disrupted by Tomivosertib. Overall, these findings demonstrate that Tomivosertib exhibits potent anti-leukemic properties on AML cells and support the development of clinical translational efforts involving the use of this drug, alone or in combination with other therapies for the treatment of AML.
RESUMEN
We provide evidence that a member of the human Schlafen (SLFN) family of proteins, SLFN5, is overexpressed in human pancreatic ductal adenocarcinoma (PDAC). Targeted deletion of SLFN5 results in decreased PDAC cell proliferation and suppresses PDAC tumorigenesis in in vivo PDAC models. Importantly, high expression levels of SLFN5 correlate with worse outcomes in PDAC patients, implicating SLFN5 in the pathophysiology of PDAC that leads to poor outcomes. Our studies establish novel regulatory effects of SLFN5 on cell cycle progression through binding/blocking of the transcriptional repressor E2F7, promoting transcription of key genes that stimulate S phase progression. Together, our studies suggest an essential role for SLFN5 in PDAC and support the potential for developing new therapeutic approaches for the treatment of pancreatic cancer through SLFN5 targeting.
Asunto(s)
Neoplasias Pancreáticas , Carcinogénesis , Línea Celular Tumoral , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias PancreáticasRESUMEN
Mnk kinases (Mnk1 and 2) are downstream effectors of Map kinase pathways and regulate phosphorylation of eukaryotic initiation factor 4E. Engagement of the Mnk pathway is critical in acute myeloid leukemia (AML) leukemogenesis and Mnk inhibitors have potent antileukemic properties in vitro and in vivo, suggesting that targeting Mnk kinases may provide a novel approach for treating AML. Here, we report the development and application of a mutation-based induced-fit in silico screen to identify novel Mnk inhibitors. The Mnk1 structure was modeled by temporarily mutating an amino acid that obstructs the ATP-binding site in the Mnk1 crystal structure while carrying out docking simulations of known inhibitors. The hit compounds display activity in Mnk biochemical and cellular assays, including acute myeloid leukemia progenitors. This approach will enable further rational structure-based drug design of new Mnk inhibitors and potentially novel ways of therapeutically targeting this kinase.
Asunto(s)
Descubrimiento de Drogas , Péptidos y Proteínas de Señalización Intracelular/antagonistas & inhibidores , Simulación del Acoplamiento Molecular , Proteínas de Neoplasias/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/química , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Leucemia Mieloide Aguda/tratamiento farmacológico , Leucemia Mieloide Aguda/enzimología , Proteínas de Neoplasias/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismoRESUMEN
Medulloblastoma is a highly malignant pediatric brain tumor associated with poor outcome. Developing treatments that target the cancer stem cell (CSC) population in medulloblastoma are important to prevent tumor relapse and induce long-lasting clinical responses. We utilized medulloblastoma neurospheres that display CSC characteristics and found activation of the PI3K/AKT pathway in sphere-forming cells. Of all class IA PI3Ks, only the PI3Kα isoform was required for sphere formation by medulloblastoma cells. Knockdown of p110α, but not p110ß or p110δ, significantly disrupted cancer stem cell frequencies as determined by extreme limiting dilution analysis (ELDA), indicating an essential role for the PI3Kα catalytic isoform in medulloblastoma CSCs. Importantly, pharmacologic inhibition of the MAPK-interacting kinase (MNK) enhanced the antineoplastic effects of targeted PI3Kα inhibition in medulloblastoma. This indicates that MNK signaling promotes survival in medulloblastoma, suggesting dual PI3Kα and MNK inhibition may provide a novel approach to target and eliminate medulloblastoma CSCs. We also observed a significant reduction in tumor formation in subcutaneous and intracranial mouse xenograft models, which further suggests that this combinatorial approach may represent an efficient therapeutic strategy for medulloblastoma. IMPLICATIONS: These findings raise the possibility of a unique therapeutic approach for medulloblastoma, involving MNK targeting to sensitize medulloblastoma CSCs to PI3Kα inhibition.
Asunto(s)
Antineoplásicos/farmacología , Neoplasias Cerebelosas/tratamiento farmacológico , Fosfatidilinositol 3-Quinasa Clase I/antagonistas & inhibidores , ATPasas Transportadoras de Cobre/antagonistas & inhibidores , Meduloblastoma/tratamiento farmacológico , Animales , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Neoplasias Cerebelosas/metabolismo , Femenino , Humanos , Meduloblastoma/metabolismo , Ratones , Ratones Desnudos , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/metabolismo , Transducción de Señal/efectos de los fármacos , Ensayos Antitumor por Modelo de Xenoinjerto/métodosRESUMEN
MAPK interacting kinase (MNK), a downstream effector of mitogen-activated protein kinase (MAPK) pathways, activates eukaryotic translation initiation factor 4E (eIF4E) and plays a key role in the mRNA translation of mitogenic and antiapoptotic genes in acute myeloid leukemia (AML) cells. We examined the antileukemic properties of a novel MNK inhibitor, SEL201. Our studies provide evidence that SEL201 suppresses eIF4E phosphorylation on Ser209 in AML cell lines and in primary patient-derived AML cells. Such effects lead to growth inhibitory effects and leukemic cell apoptosis, as well as suppression of leukemic progenitor colony formation. Combination of SEL201 with 5'-azacytidine or rapamycin results in synergistic inhibition of AML cell growth. Collectively, these results suggest that SEL201 has significant antileukemic activity and further underscore the relevance of the MNK pathway in leukemogenesis.
RESUMEN
It is well established that activation of the transcription factor signal transducer and activator of transcription 1 (STAT1) is required for the interferon-γ (IFN-γ)-mediated antiviral response. Here, we found that IFN-γ receptor stimulation also activated Unc-51-like kinase 1 (ULK1), an initiator of Beclin-1-mediated autophagy. Furthermore, the interaction between ULK1 and the mitogen-activated protein kinase kinase kinase MLK3 (mixed lineage kinase 3) was necessary for MLK3 phosphorylation and downstream activation of the kinase ERK5. This autophagy-independent activity of ULK1 promoted the transcription of key antiviral IFN-stimulated genes (ISGs) and was essential for IFN-γ-dependent antiviral effects. These findings define a previously unknown IFN-γ pathway that appears to be a key element of the antiviral response.
Asunto(s)
Homólogo de la Proteína 1 Relacionada con la Autofagia/metabolismo , Interferón gamma/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Quinasas Quinasa Quinasa PAM/metabolismo , Proteína Quinasa 7 Activada por Mitógenos/metabolismo , Animales , Autofagia , Beclina-1/metabolismo , Línea Celular Tumoral , Fosfatidilinositol 3-Quinasas Clase III/metabolismo , Citocinas/metabolismo , Perfilación de la Expresión Génica , Humanos , Inmunidad Innata , Ratones , Familia de Multigenes , Fosforilación , Unión Proteica , Receptores de Interferón/metabolismo , Proteínas Recombinantes/metabolismo , Transducción de Señal , Transcripción Genética , Células U937 , Virosis/metabolismo , Receptor de Interferón gamma , Proteina Quinasa Quinasa Quinasa 11 Activada por MitógenoRESUMEN
The human serine/threonine kinase ULK1 is the human homolog of the Caenorhabditis elegans Unc-51 kinase and of the Saccharomyces cerevisiae autophagy-related protein kinase Atg1. As Unc-51 and Atg1, ULK1 regulates both axon growth and autophagy, respectively, in mammalian cells. However, a novel immunoregulatory role of ULK1 has been recently described. This kinase was shown to be required for regulation of both type I interferon (IFN) production and induction of type I IFN signaling. Optimal regulation of IFN production is crucial for generation of effective IFN-immune responses, and defects in such networks can be detrimental for the host leading to uncontrolled pathogen infection, tumor growth, or autoimmune diseases. Thus, ULK1 plays a central role in IFN-dependent immunity. Here we review the diverse roles of ULK1, with special focus on its importance to type I IFN signaling, and highlight important future study questions.
Asunto(s)
Homólogo de la Proteína 1 Relacionada con la Autofagia/inmunología , Autofagia/inmunología , Interferón Tipo I/inmunología , Péptidos y Proteínas de Señalización Intracelular/inmunología , Transducción de Señal/inmunología , Animales , Enfermedades Autoinmunes/inmunología , Proteínas Relacionadas con la Autofagia/inmunología , Caenorhabditis elegans/inmunología , Proteínas de Caenorhabditis elegans/inmunología , Humanos , Infecciones/inmunología , Neoplasias/inmunología , Proteínas Quinasas/inmunología , Proteínas Serina-Treonina Quinasas/inmunología , Saccharomyces cerevisiae/inmunología , Proteínas de Saccharomyces cerevisiae/inmunologíaRESUMEN
Arsenic trioxide (As2O3) exhibits potent antineoplastic effects and is used extensively in clinical oncology for the treatment of a subset of patients with acute myeloid leukemia (AML). Although As2O3 is known to regulate activation of several signaling cascades, the key events, accounting for its antileukemic properties, remain to be defined. We provide evidence that arsenic can directly bind to cysteine 299 in AMPKα and inhibit its activity. This inhibition of AMPK by arsenic is required in part for its cytotoxic effects on primitive leukemic progenitors from patients with AML, while concomitant treatment with an AMPK activator antagonizes in vivo the arsenic-induced antileukemic effects in a xenograft AML mouse model. A consequence of AMPK inhibition is activation of the mTOR pathway as a negative regulatory feedback loop. However, when AMPK expression is lost, arsenic-dependent activation of the kinase RSK downstream of MAPK activity compensates the generation of regulatory feedback signals through phosphorylation of downstream mTOR targets. Thus, therapeutic regimens with As2O3 will need to include inhibitors of both the mTOR and RSK pathways in combination to prevent engagement of negative feedback loops and maximize antineoplastic responses.
Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Antineoplásicos/farmacología , Arsenicales/farmacología , Leucemia Mieloide Aguda/tratamiento farmacológico , Óxidos/farmacología , Animales , Trióxido de Arsénico , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Humanos , Leucemia Mieloide Aguda/metabolismo , Ratones , Proteínas Quinasas S6 Ribosómicas 90-kDa/metabolismo , Transducción de Señal/efectos de los fármacos , Serina-Treonina Quinasas TOR/metabolismo , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
We provide evidence that the Unc-51-like kinase 1 (ULK1) is activated during engagement of the type I interferon (IFN) receptor (IFNR). Our studies demonstrate that the function of ULK1 is required for gene transcription mediated via IFN-stimulated response elements (ISRE) and IFNγ activation site (GAS) elements and controls expression of key IFN-stimulated genes (ISGs). We identify ULK1 as an upstream regulator of p38α mitogen-activated protein kinase (MAPK) and establish that the regulatory effects of ULK1 on ISG expression are mediated possibly by engagement of the p38 MAPK pathway. Importantly, we demonstrate that ULK1 is essential for antiproliferative responses and type I IFN-induced antineoplastic effects against malignant erythroid precursors from patients with myeloproliferative neoplasms. Together, these data reveal a role for ULK1 as a key mediator of type I IFNR-generated signals that control gene transcription and induction of antineoplastic responses.