Referencia

Cancer Res 2009; 69: (19). October 1, 2009

Autores

Laia Caja, Patricia Sancho, Esther Bertran, Daniel Iglesias-Serret, Joan Gil, Isabel Fabregat

Resumen

La sobre-activación de la vía MEK/ERK induce resistencia a los efectos pro-apoptóticos del TGF-beta en células tumorales hepáticas, ya que impide la inducción de la expresión de NOX4, una NADPH oxidasa generadora de especies reactivas de oxígeno que juega un papel esencial en el mecanismo mitocondrial de muerte celular mediado por TGF-beta. La inhibición farmacológica, o por medio de siRNAs, de la vía MEK/ERK sensibiliza a las células tumorales hepáticas a los efectos supresores del TGF-beta.

Descripción

Transforming growth factor-beta (TGF-ß) induces apoptosis in hepatocytes, being considered a liver tumor suppressor. However, many human hepatocellular carcinoma (HCC) cells escape from its pro-apoptotic effects, gaining response to this cytokine in terms of malignancy. We have recently reported that the apoptosis induced by TGF-ß in hepatocytes requires up-regulation of the NADPH oxidase NOX4, which mediates reactive oxygen species (ROS) production. TGF-ß-induced NOX4 expression is inhibited by anti-apoptotic signals, such as the phosphatydilinositol-3-phosphate kinase or the MAPK/ERK pathways. The aim of the present work was to analyze whether resistance to TGF-ß-induced apoptosis in HCC cells is related to impairment of NOX4 up-regulation due to overactivation of survival signals. Results indicate that inhibition of the MEK/ERK pathway in HepG2 cells, which are refractory to the pro-apoptotic effects of TGF-ß, sensitizes them to cell death through a mitochondrial-dependent mechanism, coincident with increased levels of BIM and BMF, decreased levels of BCL-XL and MCL1, and BAX/BAK activation. Regulation of BMF, BCL-XL and MCL1 occurs at the mRNA level, whereas BIM regulation occurs post-transcriptionally. ROS production and glutathione depletion are only observed in cells treated with TGF-ß and PD98059, which correlates with NOX4 up-regulation. Targeting knock-down of NOX4 impairs ROS increase and all the mitochondrial-dependent apoptotic features, by a mechanism that is upstream from the regulation of BIM, BMF, BCL-XL and MCL1 levels. In conclusion, overactivation of the MEK/ERK pathway in liver tumor cells confers resistance to TGF-ß-induced cell death through impairing NOX4 up-regulation, which is required for an efficient mitochondrial-dependent apoptosis.

Imagen artículo Noviembre

(Autores del artículo de izquierda a derecha: Joan Gil, Laia Caja, Patricia Sancho, Esther Bertran, Daniel Iglesias-Serret, Isabel Fabregat) Patricia Sancho es investigadora postdoctoral del programa Sara Borrell del Instituto de Salud Carlos III (Ministerio de Ciencia e Innovación), en el grupo de Isabel Fabregat en el Instituto de Investigació Biomèdica de Bellvitge (IDIBELL), Hospitalet, Barcelona.

Descárgate este artículo aquí

¿Acabas de publicar un artículo interesante?

Manda la referencia a través de nuestro formulario.  Límite de edad 32 años. Los artículos seleccionados serán destacados como artículos del mes y participarán en el Premio al mejor artículo de jóvenes de la SEBBM, que se entregará en el congreso de la SEBBM (inscripción y alojamiento gratuitos).

Otros "Artículos del mes"

p73 regulates ependymal planar cell polarity by modulating actin and microtubule cytoskeleton

01-03-2019

Planar cell polarity (PCP) and intercellular junctional complexes establish tissue structure and coordinated behaviors across epithelial sheets. In multiciliated ependymal cells, rotational and translational PCP coordinate cilia beating and direct...

Leer más

β‐RA reduces DMQ/CoQ ratio and rescues the encephalopathic phenotype in Coq9R239X mice

01-02-2019

Coenzyme Q (CoQ) deficiency has been associated with primary defects in the CoQ biosynthetic pathway or to secondary events. In some cases, the exogenous CoQ supplementation has limited efficacy. In...

Leer más

Small molecule inhibits α-synuclein aggregation, disrupts amyloid fibrils, and prevents degeneration of dopaminergic neurons

02-01-2019

Parkinson's disease (PD) is characterized by a progressive loss of dopaminergic neurons, a process that current therapeutic approaches cannot prevent. In PD, the typical pathological hallmark is the accumulation of...

Leer más

Dynamic acetylation of cytosolic phosphoenolpyruvate carboxykinase toggles enzyme activity between gluconeogenic and anaplerotic reactions

01-12-2018

Cytosolic phosphoenolpyruvate carboxykinase (PCK1) is considered a gluconeogenic enzyme; however, its metabolic functions and regulatory mechanisms beyond gluconeogenesis are poorly understood. Here, we describe that dynamic acetylation of PCK1 interconverts...

Leer más

The Helicase PIF1 Facilitates Resection overSequences Prone to Forming G4 Structures

02-11-2018

DNA breaks are complex lesions that can be repaired either by non-homologous end joining (NHEJ) or by homologous recombination (HR). The decision between these two routes of DNA repair is...

Leer más

Preventing loss of mechanosensation by the nuclear membranes of alveolar cells reduces lung injury in mice during mechanical ventilation

01-10-2018

The nuclear membrane acts as a mechanosensor that drives cellular responses following changes in the extracellular environment. Mechanically ventilated lungs are exposed to an abnormally high mechanical load that may...

Leer más

Oxidative stress is tightly regulated by cytochrome c phosphorylation and respirasome factors in mitochondria

03-09-2018

Respiratory cytochrome c has been found to be phosphorylated at tyrosine 97 in the postischemic brain upon neuroprotective insulin treatment, but how such posttranslational modification affects mitochondrial metabolism is unclear...

Leer más

STAT3 labels a subpopulation of reactive astrocytes required for brain metastasis

01-08-2018

The brain microenvironment imposes a particularly intense selective pressure on metastasis-initiating cells, but successful metastases bypass this control through mechanisms that are poorly understood. Reactive astrocytes are key components of...

Leer más

A broad atlas of somatic hypermutation allows prediction of activation-induced deaminase targets

02-07-2018

Activation-induced deaminase (AID) initiates antibody diversification in germinal center (GC) B cells through the deamination of cytosines on immunoglobulin genes. AID can also target other regions in the genome, triggering...

Leer más

Deciphering the Dynamic Transcriptional and Post-transcriptional Networks of Macrophages in the Healthy Heart and after Myocardial Injury

01-06-2018

Our group is interested in the behavior and transcriptional regulation of macrophages in the context of complex disease environments. We have generated a whole transcriptome dataset (mRNA, miRNA, and lincRNA)...

Leer más

Socios Protectores