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1.
J Proteome Res ; 14(9): 3996-4004, 2015 Sep 04.
Artículo en Inglés | MEDLINE | ID: mdl-26214752

RESUMEN

Under various pathological conditions, such as inflammation, ischemia and in solid tumors, physiological parameters (local oxygen tension or extracellular pH) show distinct tissue abnormalities (hypoxia and acidosis). For tumors, the prevailing microenvironment exerts a strong influence on the phenotype with respect to proliferation, invasion, and metastasis formation and therefore influences prognosis. In this study, we investigate the impact of extracellular metabolic acidosis (pH 7.4 versus 6.6) on the proteome patterns of a prostate cancer-derived tumor cell type (AT-1) using isobaric labeling and LC-MS/MS analysis. In total, 2710 proteins were identified and quantified across four biological replicates, of which seven were significantly affected with changes >50% and used for validation. Glucose transporter 1 and farnesyl pyrophosphatase were found to be down-regulated after 48 h of acidic treatment, and metallothionein 2A was reduced after 24 h and returned to control values after 48 h. After 24 and 48 h at pH 6.6, glutathione S transferase A3 and NAD(P)H dehydrogenase 1, cellular retinoic acid-binding protein 2, and Na-bicarbonate transporter 3 levels were found to be increased. The changes in protein levels were confirmed by transcriptome and functional analyses. In addition to the experimental in-depth investigation of proteins with changes >50%, functional profiling (statistical enrichment analysis) including proteins with changes >20% revealed that acidosis upregulates GSH metabolic processes, citric acid cycle, and respiratory electron transport. Metabolism of lipids and cholesterol biosynthesis were downregulated. Our data comprise the first comprehensive report on acidosis-induced changes in proteome patterns of a tumor cell line.


Asunto(s)
Acidosis , Modelos Biológicos , Neoplasias de la Próstata/metabolismo , Proteoma/análisis , Proteoma/efectos de los fármacos , Animales , Caspasa 3/metabolismo , Línea Celular Tumoral , Cromatografía Liquida , Glucosa/metabolismo , Glutatión Transferasa/metabolismo , Concentración de Iones de Hidrógeno , Masculino , ARN Mensajero/metabolismo , Ratas , Espectrometría de Masas en Tándem
2.
Adv Exp Med Biol ; 789: 221-228, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23852498

RESUMEN

Cells in solid tumors generate an extracellular acidosis due to the Warburg effect and tissue hypoxia. Acidosis can affect the functional behavior of tumor cells, causing, e.g., multidrug resistance. In this process ERK1/2 and p38 mitogen-activated protein kinases (MAPK) seem to play a key role. However, the underlying mechanism of MAPK activation by extracellular acidosis remains unclear. Experiments were performed in three tumor and three normal tissue cell lines in which the cells were exposed to an extracellular pH of 6.6 for 3 h. Intracellular pH (pHi), protein expression and activation, acidosis-induced transactivation, and reactive oxygen species (ROS) formation were measured. Extracellular acidosis resulted in a rapid and sustained decrease of pHi leading to a reversal of the extra-/intracellular pH gradient. Extracellular acidosis led to p38 phosphorylation in all cell types and to ERK1/2 phosphorylation in three of six cell lines. Furthermore, p38 phosphorylation was also observed during sole intracellular lactacidosis at normal pHe. Acidosis-enhanced formation of ROS, probably originating from mitochondria, seems to trigger MAPK phosphorylation. Finally, acidosis increased phosphorylation of the transcription factor CREB and resulted in increased transcriptional activity. Thus, an acidic tumor microenvironment can induce a longer-lasting p38 CREB-mediated change in the transcriptional program.


Asunto(s)
Acidosis/metabolismo , Neoplasias/metabolismo , Transducción de Señal/fisiología , Microambiente Tumoral/fisiología , Animales , Células CHO , Línea Celular , Línea Celular Tumoral , Cricetulus , Perros , Humanos , Concentración de Iones de Hidrógeno , Sistema de Señalización de MAP Quinasas , Células de Riñón Canino Madin Darby , Fosforilación , Especies Reactivas de Oxígeno/metabolismo , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismo
3.
Nat Commun ; 12(1): 5096, 2021 08 19.
Artículo en Inglés | MEDLINE | ID: mdl-34413294

RESUMEN

Nearly all mass gathering events worldwide were banned at the beginning of the COVID-19 pandemic, as they were suspected of presenting a considerable risk for the transmission of SARS-CoV-2. We investigated the risk of transmitting SARS-CoV-2 by droplets and aerosols during an experimental indoor mass gathering event under three different hygiene practices, and used the data in a simulation study to estimate the resulting burden of disease under conditions of controlled epidemics. Our results show that the mean number of measured direct contacts per visitor was nine persons and this can be reduced substantially by appropriate hygiene practices. A comparison of two versions of ventilation with different air exchange rates and different airflows found that the system which performed worst allowed a ten-fold increase in the number of individuals exposed to infectious aerosols. The overall burden of infections resulting from indoor mass gatherings depends largely on the quality of the ventilation system and the hygiene practices. Presuming an effective ventilation system, indoor mass gathering events with suitable hygiene practices have a very small, if any, effect on epidemic spread.


Asunto(s)
Contaminación del Aire Interior/prevención & control , COVID-19/transmisión , Higiene/normas , SARS-CoV-2/patogenicidad , Ventilación/métodos , Aerosoles , COVID-19/diagnóstico , COVID-19/virología , Simulación por Computador , Transmisión de Enfermedad Infecciosa/prevención & control , Humanos , SARS-CoV-2/genética , SARS-CoV-2/aislamiento & purificación
4.
PLoS One ; 6(7): e22445, 2011.
Artículo en Inglés | MEDLINE | ID: mdl-21818325

RESUMEN

Tumor micromilieu often shows pronounced acidosis forcing cells to adapt their phenotype towards enhanced tumorigenesis induced by altered cellular signalling and transcriptional regulation. In the presents study mechanisms and potential consequences of the crosstalk between extra- and intracellular pH (pH(e), pH(i)) and mitogen-activated-protein-kinases (ERK1/2, p38) was analyzed. Data were obtained mainly in AT1 R-3327 prostate carcinoma cells, but the principle importance was confirmed in 5 other cell types. Extracellular acidosis leads to a rapid and sustained decrease of pH(i) in parallel to p38 phosphorylation in all cell types and to ERK1/2 phosphorylation in 3 of 6 cell types. Furthermore, p38 phosphorylation was elicited by sole intracellular lactacidosis at normal pH(e). Inhibition of ERK1/2 phosphorylation during acidosis led to necrotic cell death. No evidence for the involvement of the kinases c-SRC, PKC, PKA, PI3K or EGFR nor changes in cell volume in acidosis-induced MAPK activation was obtained. However, our data reveal that acidosis enhances the formation of reactive oxygen species (ROS), probably originating from mitochondria, which subsequently trigger MAPK phosphorylation. Scavenging of ROS prevented acidosis-induced MAPK phosphorylation whereas addition of H(2)O(2) enhanced it. Finally, acidosis increased phosphorylation of the transcription factor CREB via p38, leading to increased transcriptional activity of a CRE-reporter even 24 h after switching the cells back to a normal environmental milieu. Thus, an acidic tumor microenvironment can induce a longer lasting p38-CREB-medited change in the transcriptional program, which may maintain the altered phenotype even when the cells leave the tumor environment.


Asunto(s)
Ácidos/metabolismo , Sistema de Señalización de MAP Quinasas , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Neoplasias/enzimología , Neoplasias/patología , Especies Reactivas de Oxígeno/metabolismo , Microambiente Tumoral , Animales , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Perros , Activación Enzimática/efectos de los fármacos , Espacio Extracelular/efectos de los fármacos , Espacio Extracelular/metabolismo , Humanos , Concentración de Iones de Hidrógeno/efectos de los fármacos , Espacio Intracelular/efectos de los fármacos , Espacio Intracelular/metabolismo , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Modelos Biológicos , Fosforilación/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Tirosina Quinasas/metabolismo , Ratas , ATPasa Intercambiadora de Sodio-Potasio/metabolismo , Microambiente Tumoral/efectos de los fármacos
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