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1.
Mol Cell ; 77(6): 1322-1339.e11, 2020 03 19.
Artículo en Inglés | MEDLINE | ID: mdl-32006464

RESUMEN

Deregulated expression of MYC induces a dependence on the NUAK1 kinase, but the molecular mechanisms underlying this dependence have not been fully clarified. Here, we show that NUAK1 is a predominantly nuclear protein that associates with a network of nuclear protein phosphatase 1 (PP1) interactors and that PNUTS, a nuclear regulatory subunit of PP1, is phosphorylated by NUAK1. Both NUAK1 and PNUTS associate with the splicing machinery. Inhibition of NUAK1 abolishes chromatin association of PNUTS, reduces spliceosome activity, and suppresses nascent RNA synthesis. Activation of MYC does not bypass the requirement for NUAK1 for spliceosome activity but significantly attenuates transcription inhibition. Consequently, NUAK1 inhibition in MYC-transformed cells induces global accumulation of RNAPII both at the pause site and at the first exon-intron boundary but does not increase mRNA synthesis. We suggest that NUAK1 inhibition in the presence of deregulated MYC traps non-productive RNAPII because of the absence of correctly assembled spliceosomes.


Asunto(s)
Núcleo Celular/metabolismo , Cromatina/metabolismo , Proteínas Quinasas/metabolismo , Proteína Fosfatasa 1/antagonistas & inhibidores , Proteínas Proto-Oncogénicas c-myc/metabolismo , Proteínas Represoras/metabolismo , Empalmosomas/metabolismo , Transcripción Genética , Animales , Núcleo Celular/genética , Cromatina/genética , Regulación de la Expresión Génica , Células HeLa , Humanos , Ratones , Células 3T3 NIH , Fosforilación , Proteínas Quinasas/genética , Proteína Fosfatasa 1/genética , Proteína Fosfatasa 1/metabolismo , Proteínas Proto-Oncogénicas c-myc/genética , ARN Polimerasa II/genética , ARN Polimerasa II/metabolismo , Empalme del ARN , Proteínas Represoras/genética , Empalmosomas/genética
3.
Z Rheumatol ; 83(1): 54-67, 2024 Feb.
Artículo en Alemán | MEDLINE | ID: mdl-38019334

RESUMEN

The ability to visualize the nerves of the lower extremities differs from that of the upper extremities in sonography because the soft tissue cover is significantly larger in some cases. Landmarks are also defined for the lower extremities, which enable precise visualization of the nerves. Nerves and muscles are to be understood as a functional unit. In addition to the clarification of nerve compression syndromes, polyneuropathies and nerve tumors, sonography is also used to visualize muscle atrophy.


Asunto(s)
Síndromes de Compresión Nerviosa , Polineuropatías , Humanos , Ultrasonografía , Extremidad Inferior/diagnóstico por imagen
4.
J Biol Chem ; 291(21): 11252-67, 2016 05 20.
Artículo en Inglés | MEDLINE | ID: mdl-27030009

RESUMEN

The spindle assembly checkpoint (SAC) is an essential safeguarding mechanism devised to ensure equal chromosome distribution in daughter cells upon mitosis. The proteins Bub3 and BubR1 are key components of the mitotic checkpoint complex, an essential part of the molecular machinery on which the SAC relies. In the present work we have performed a detailed functional and biochemical characterization of the interaction between human Bub3 and BubR1 in cells and in vitro Our results demonstrate that genetic knockdown of Bub3 abrogates the SAC, promotes apoptosis, and inhibits the proliferation of human cancer cells. We also show that the integrity of the human mitotic checkpoint complex depends on the specific recognition between BubR1 and Bub3, for which the BubR1 Gle2 binding sequence motif is essential. This 1:1 binding event is high affinity, enthalpy-driven and with slow dissociation kinetics. The affinity, kinetics, and thermodynamic parameters of the interaction are differentially modulated by small regions in the N and C termini of the Gle2 binding domain sequence, suggesting the existence of "hotspots" for this protein-protein interaction. Furthermore, we show that specific disruption of endogenous BubR1·Bub3 complexes in human cancer cells phenocopies the effects observed in gene targeting experiments. Our work enhances the current understanding of key members of the SAC and paves the road for the pursuit of novel targeted cancer therapies based on SAC inhibition.


Asunto(s)
Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Puntos de Control de la Fase M del Ciclo Celular/fisiología , Proteínas Serina-Treonina Quinasas/química , Proteínas Serina-Treonina Quinasas/metabolismo , Huso Acromático/metabolismo , Apoptosis , Proteínas de Ciclo Celular/genética , Línea Celular , Línea Celular Tumoral , Proliferación Celular , Técnicas de Silenciamiento del Gen , Células HeLa , Humanos , Cinética , Puntos de Control de la Fase M del Ciclo Celular/genética , Células MCF-7 , Modelos Moleculares , Proteínas de Unión a Poli-ADP-Ribosa , Dominios y Motivos de Interacción de Proteínas , Proteínas Serina-Treonina Quinasas/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Huso Acromático/genética , Termodinámica
5.
Exp Cell Res ; 323(1): 131-143, 2014 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-24480576

RESUMEN

Cancer cells in poorly vascularized tumor regions need to adapt to an unfavorable metabolic microenvironment. As distance from supplying blood vessels increases, oxygen and nutrient concentrations decrease and cancer cells react by stopping cell cycle progression and becoming dormant. As cytostatic drugs mainly target proliferating cells, cancer cell dormancy is considered as a major resistance mechanism to this class of anti-cancer drugs. Therefore, substances that target cancer cells in poorly vascularized tumor regions have the potential to enhance cytostatic-based chemotherapy of solid tumors. With three-dimensional growth conditions, multicellular tumor spheroids (MCTS) reproduce several parameters of the tumor microenvironment, including oxygen and nutrient gradients as well as the development of dormant tumor regions. We here report the setup of a 3D cell culture compatible high-content screening system and the identification of nine substances from two commercially available drug libraries that specifically target cells in inner MCTS core regions, while cells in outer MCTS regions or in 2D cell culture remain unaffected. We elucidated the mode of action of the identified compounds as inhibitors of the respiratory chain and show that induction of cell death in inner MCTS core regions critically depends on extracellular glucose concentrations. Finally, combinational treatment with cytostatics showed increased induction of cell death in MCTS. The data presented here shows for the first time a high-content based screening setup on 3D tumor spheroids for the identification of substances that specifically induce cell death in inner tumor spheroid core regions. This validates the approach to use 3D cell culture screening systems to identify substances that would not be detectable by 2D based screening in otherwise similar culture conditions.


Asunto(s)
Antineoplásicos/aislamiento & purificación , Inhibidores Enzimáticos/aislamiento & purificación , Esferoides Celulares/efectos de los fármacos , Antineoplásicos/farmacología , Técnicas de Cultivo de Célula , Puntos de Control del Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales/métodos , Transporte de Electrón/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Femenino , Glucosa/metabolismo , Humanos , Estaurosporina/farmacología , Células Tumorales Cultivadas , Microambiente Tumoral/fisiología
6.
J Immunother Cancer ; 11(11)2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37963637

RESUMEN

BACKGROUND: The metabolism of tryptophan to kynurenines (KYN) by indoleamine-2,3-dioxygenase or tryptophan-2,3-dioxygenase is a key pathway of constitutive and adaptive tumor immune resistance. The immunosuppressive effects of KYN in the tumor microenvironment are predominantly mediated by the aryl hydrocarbon receptor (AhR), a cytosolic transcription factor that broadly suppresses immune cell function. Inhibition of AhR thus offers an antitumor therapy opportunity via restoration of immune system functions. METHODS: The expression of AhR was evaluated in tissue microarrays of head and neck squamous cell carcinoma (HNSCC), non-small cell lung cancer (NSCLC) and colorectal cancer (CRC). A structure class of inhibitors that block AhR activation by exogenous and endogenous ligands was identified, and further optimized, using a cellular screening cascade. The antagonistic properties of the selected AhR inhibitor candidate BAY 2416964 were determined using transactivation assays. Nuclear translocation, target engagement and the effect of BAY 2416964 on agonist-induced AhR activation were assessed in human and mouse cancer cells. The immunostimulatory properties on gene and cytokine expression were examined in human immune cell subsets. The in vivo efficacy of BAY 2416964 was tested in the syngeneic ovalbumin-expressing B16F10 melanoma model in mice. Coculture of human H1299 NSCLC cells, primary peripheral blood mononuclear cells and fibroblasts mimicking the human stromal-tumor microenvironment was used to assess the effects of AhR inhibition on human immune cells. Furthermore, tumor spheroids cocultured with tumor antigen-specific MART-1 T cells were used to study the antigen-specific cytotoxic T cell responses. The data were analyzed statistically using linear models. RESULTS: AhR expression was observed in tumor cells and tumor-infiltrating immune cells in HNSCC, NSCLC and CRC. BAY 2416964 potently and selectively inhibited AhR activation induced by either exogenous or endogenous AhR ligands. In vitro, BAY 2416964 restored immune cell function in human and mouse cells, and furthermore enhanced antigen-specific cytotoxic T cell responses and killing of tumor spheroids. In vivo, oral application with BAY 2416964 was well tolerated, induced a proinflammatory tumor microenvironment, and demonstrated antitumor efficacy in a syngeneic cancer model in mice. CONCLUSIONS: These findings identify AhR inhibition as a novel therapeutic approach to overcome immune resistance in various types of cancers.


Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas , Dioxigenasas , Neoplasias de Cabeza y Cuello , Neoplasias Pulmonares , Humanos , Ratones , Animales , Triptófano , Receptores de Hidrocarburo de Aril/genética , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Leucocitos Mononucleares/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Quinurenina/metabolismo , Inmunoterapia , Factores Inmunológicos , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Microambiente Tumoral
7.
J Med Chem ; 63(2): 601-612, 2020 01 23.
Artículo en Inglés | MEDLINE | ID: mdl-31859507

RESUMEN

The serine/threonine kinase TBK1 (TANK-binding kinase 1) and its homologue IKKε are noncanonical members of the inhibitor of the nuclear factor κB (IκB) kinase family. These kinases play important roles in multiple cellular pathways and, in particular, in inflammation. Herein, we describe our investigations on a family of benzimidazoles and the identification of the potent and highly selective TBK1/IKKε inhibitor BAY-985. BAY-985 inhibits the cellular phosphorylation of interferon regulatory factor 3 and displays antiproliferative efficacy in the melanoma cell line SK-MEL-2 but showed only weak antitumor activity in the SK-MEL-2 human melanoma xenograft model.


Asunto(s)
Quinasa I-kappa B/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Bencimidazoles/síntesis química , Bencimidazoles/farmacología , Sitios de Unión , Cristalografía por Rayos X , Descubrimiento de Drogas , Ensayos Analíticos de Alto Rendimiento , Humanos , Modelos Moleculares , Fosforilación , Relación Estructura-Actividad , Especificidad por Sustrato
8.
J Med Chem ; 62(2): 928-940, 2019 01 24.
Artículo en Inglés | MEDLINE | ID: mdl-30563338

RESUMEN

The availability of a chemical probe to study the role of a specific domain of a protein in a concentration- and time-dependent manner is of high value. Herein, we report the identification of a highly potent and selective ERK5 inhibitor BAY-885 by high-throughput screening and subsequent structure-based optimization. ERK5 is a key integrator of cellular signal transduction, and it has been shown to play a role in various cellular processes such as proliferation, differentiation, apoptosis, and cell survival. We could demonstrate that inhibition of ERK5 kinase and transcriptional activity with a small molecule did not translate into antiproliferative activity in different relevant cell models, which is in contrast to the results obtained by RNAi technology.


Asunto(s)
Proteína Quinasa 7 Activada por Mitógenos/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/química , Piridinas/química , Pirimidinas/química , Apoptosis/efectos de los fármacos , Sitios de Unión , Diferenciación Celular/efectos de los fármacos , Línea Celular , Proliferación Celular/efectos de los fármacos , Cristalografía por Rayos X , Evaluación Preclínica de Medicamentos , Semivida , Humanos , Proteína Quinasa 7 Activada por Mitógenos/metabolismo , Simulación del Acoplamiento Molecular , Inhibidores de Proteínas Quinasas/metabolismo , Inhibidores de Proteínas Quinasas/farmacología , Estructura Terciaria de Proteína , Piridinas/metabolismo , Piridinas/farmacología , Pirimidinas/metabolismo , Pirimidinas/farmacología , Transducción de Señal/efectos de los fármacos , Relación Estructura-Actividad , Transcripción Genética/efectos de los fármacos
9.
Fertil Steril ; 99(3): 927-935.e6, 2013 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-23260859

RESUMEN

OBJECTIVE: To develop a predictive mouse model for uterine fibroids. DESIGN: Human fibroid cells xenografted to immunodeficient mice. SETTING: University and industrial research center. ANIMAL(S): Immunodeficient scid/beige mice. INTERVENTION(S): Subcutaneous and intrauterine injection of fibroid-derived cells, SV40 transformation of primary cells by lentiviral transduction, proliferation determined by immunohistochemistry, FISH. MAIN OUTCOME MEASURE(S): Characterization of primary and immortalized cells by Western blot and soft agar assay, determination of in vivo tumorigenicity, comparative histology and immunohistochemistry, fluorescence in situ hybridization. RESULT(S): Tumorigenicity of primary myoma cells disappears upon in vitro culture. Transformation and immortalization does not restore or conserve the in vivo growth potential of cultured cells. Injection of primary cells into myometrium of mice leads to xenografts with a leiomyoma-like histology. CONCLUSION(S): Primary myoma cells are suited to generate fibroid-like xenografts for studying pathogenesis without genetic modifications. In contrast, in vitro culture abolishes transplantability, and neither transformation nor immortalization is sufficient to restore tumorigenic capacity.


Asunto(s)
Modelos Animales de Enfermedad , Leiomioma/patología , Ratones SCID , Neoplasias Uterinas/patología , Adenocarcinoma/patología , Animales , Línea Celular Transformada , Línea Celular Tumoral , Femenino , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Leiomioma/fisiopatología , Neoplasias Pulmonares/patología , Ratones , Cultivo Primario de Células , Neoplasias Uterinas/fisiopatología , Ensayos Antitumor por Modelo de Xenoinjerto
10.
PLoS One ; 7(5): e36125, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22563479

RESUMEN

Silencing of genes by hypermethylation contributes to cancer progression and has been shown to occur with increased frequency at specific genomic loci. However, the precise mechanisms underlying the establishment and maintenance of aberrant methylation marks are still elusive. The de novo DNA methyltransferase 3B (DNMT3B) has been suggested to play an important role in the generation of cancer-specific methylation patterns. Previous studies have shown that a reduction of DNMT3B protein levels induces antiproliferative effects in cancer cells that were attributed to the demethylation and reactivation of tumor suppressor genes. However, methylation changes have not been analyzed in detail yet. Using RNA interference we reduced DNMT3B protein levels in colon cancer cell lines. Our results confirm that depletion of DNMT3B specifically reduced the proliferation rate of DNMT3B-overexpressing colon cancer cell lines. However, genome-scale DNA methylation profiling failed to reveal methylation changes at putative DNMT3B target genes, even in the complete absence of DNMT3B. These results show that DNMT3B is dispensable for the maintenance of aberrant DNA methylation patterns in human colon cancer cells and they have important implications for the development of targeted DNA methyltransferase inhibitors as epigenetic cancer drugs.


Asunto(s)
Proliferación Celular , ADN (Citosina-5-)-Metiltransferasas/genética , Metilación de ADN , Interferencia de ARN , Células CACO-2 , Línea Celular , Línea Celular Tumoral , Supervivencia Celular/genética , Neoplasias del Colon/genética , Neoplasias del Colon/metabolismo , Neoplasias del Colon/patología , ADN (Citosina-5-)-Metiltransferasas/metabolismo , Regulación Enzimológica de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Células HCT116 , Células HT29 , Humanos , Immunoblotting , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , ADN Metiltransferasa 3B
11.
Nat Commun ; 2: 395, 2011 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-21772266

RESUMEN

High attrition rates of novel anti-cancer drugs highlight the need for improved models to predict toxicity. Although polo-like kinase 1 (Plk1) inhibitors are attractive candidates for drug development, the role of Plk1 in primary cells remains widely unexplored. Therefore, we evaluated the utility of an RNA interference-based model to assess responses to an inducible knockdown (iKD) of Plk1 in adult mice. Here we show that Plk1 silencing can be achieved in several organs, although adverse events are rare. We compared responses in Plk1-iKD mice with those in primary cells kept under controlled culture conditions. In contrast to the addiction of many cancer cell lines to the non-oncogene Plk1, the primary cells' proliferation, spindle assembly and apoptosis exhibit only a low dependency on Plk1. Responses to Plk1-depletion, both in cultured primary cells and in our iKD-mouse model, correspond well and thus provide the basis for using validated iKD mice in predicting responses to therapeutic interventions.


Asunto(s)
Antineoplásicos/toxicidad , Proteínas de Ciclo Celular/antagonistas & inhibidores , Neoplasias/tratamiento farmacológico , Proteínas Serina-Treonina Quinasas/antagonistas & inhibidores , Proteínas Proto-Oncogénicas/antagonistas & inhibidores , Interferencia de ARN/efectos de los fármacos , Pruebas de Toxicidad/métodos , Animales , Apoptosis/genética , Northern Blotting , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Células Cultivadas , Cartilla de ADN/genética , Evaluación Preclínica de Medicamentos , Citometría de Flujo , Técnica del Anticuerpo Fluorescente , Dosificación de Gen/genética , Técnicas de Silenciamiento del Gen , Ingeniería Genética/métodos , Humanos , Ratones , Ratones Transgénicos , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Proto-Oncogénicas/genética , Proteínas Proto-Oncogénicas/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transfección , Quinasa Tipo Polo 1
13.
J Biol Chem ; 277(33): 29817-24, 2002 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-12021264

RESUMEN

Apoptotic cell death is of central importance in the pathogenesis of viral infections. Activation of a cascade of cysteine proteases, i.e. caspases, plays a key role in the effector phase of virus-induced apoptosis. However, little is known about pathways leading to the activation of initiator caspases in virus-infected host cells. Recently, we have shown that Sendai virus (SeV) infection triggers apoptotic cell death by activation of the effector caspase-3 and initiator caspase-8. We now investigated mechanisms leading to the activation of another initiator caspase, caspase-9. Unexpectedly we found that caspase-9 cleavage is not dependent on the presence of active caspases-3 or -8. Furthermore, the presence of caspase-9 in mouse embryonic fibroblast (MEF) cells was a prerequisite for Sendai virus-induced apoptotic cell death. Caspase-9 activation occurred without the release of cytochrome c from mitochondria and was not dependent on the presence of Apaf-1 or reactive oxygen intermediates. Our results therefore suggest an alternative mechanism for caspase-9 activation in virally infected cells beside the well characterized pathways via death receptors or mitochondrial cytochrome c release.


Asunto(s)
Caspasas/metabolismo , Proteínas/metabolismo , Virus Sendai/fisiología , Animales , Factor Apoptótico 1 Activador de Proteasas , Caspasa 8 , Caspasa 9 , Activación Enzimática , Humanos , Hidrólisis , Ratones , Especies Reactivas de Oxígeno , Células Tumorales Cultivadas
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