RESUMEN
Breast cancer is a prevalent neoplastic disease among women worldwide which treatments still present several side effects and resistance. Considering that cancer cells present derangements in their energetic homeostasis, and that peroxisome proliferator-activated receptor- gamma coactivator 1 (PGC-1) is crucial for cellular metabolism and redox signaling, the main objective of this study was to investigate whether there is a relationship between PGC-1 expression, the proliferation of breast cancer cells and the mechanisms involved. We initially assessed PGC-1ß expression in complementary DNA (cDNA) from breast tumor of patients bearing luminal A, luminal B, and HER2-overexpressed and triple negative tumors. Our data showed that PGC-1ß expression is increased in patients bearing HER2-overexpressing tumors as compared to others subtypes. Using quantitative PCR and immunoblotting, we showed that breast cancer cells with HER2-amplification (SKBR-3) have greater expression of PGC-1ß as compared to a non-tumorous breast cell (MCF-10A) and higher proliferation rate. PGC-1ß expression was knocked down with short interfering RNA in HER2-overexpressing cells, and cells decreased proliferation. In these PGC-1ß-inhibited cells, we found increased citrate synthase activity and no marked changes in mitochondrial respiration. Glycolytic pathway was decreased, characterized by lower intracellular lactate levels. In addition, after PGC-1ß knockdown, SKBR-3 cells showed increased reactive oxygen species production, no changes in antioxidant activity, and decreased expression of ERRα, a modulator of metabolism. In conclusion, we show an association of HER2-overexpression and PGC-1ß. PGC-1ß knockdown impairs HER2-overexpressing cells proliferation acting on ERRα signaling, metabolism, and redox balance.
Asunto(s)
Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Proteínas Portadoras/metabolismo , Regulación Neoplásica de la Expresión Génica , Genes erbB-2 , Redes y Vías Metabólicas , Oxidación-Reducción , Anciano , Neoplasias de la Mama/patología , Línea Celular Tumoral , Proliferación Celular , Supervivencia Celular/genética , Femenino , Técnicas de Silenciamiento del Gen , Silenciador del Gen , Humanos , Persona de Mediana Edad , Clasificación del Tumor , Estadificación de Neoplasias , ARN Interferente Pequeño/genética , Proteínas de Unión al ARN , Especies Reactivas de Oxígeno , Receptores de Estrógenos/genética , Receptores de Estrógenos/metabolismo , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/metabolismo , Neoplasias de la Mama Triple Negativas/patología , Carga Tumoral , Receptor Relacionado con Estrógeno ERRalfaRESUMEN
Septic encephalopathy represents the most frequently observed form of encephalopathy in intensive care units. Interactions between the immune and nervous systems have been observed in experimental sepsis. Therefore, the aim of the current study was to characterize the effect of different severities of sepsis on encephalopathy and the inflammatory profile of the spleen. We hypothesized that different grades of sepsis severity would lead to variations in encephalopathy and activation of spleen cells. We induced sepsis of different severities in Balb/c mice by cecal ligature and puncture (CLP). Six and 12 h after CLP induction, behavioral impairment was assessed by the SmithKline/Harwell/Imperial College/Royal Hospital/Phenotype Assessment (SHIRPA) test. The animals were then killed, and the plasma, spleen, and hippocampus were removed. Levels of the encephalopathy marker S100ß were measured in plasma. Spleens were weighed and then a characterization of splenic lymphocytes was performed by flow cytometry (cytotoxic T lymphocyte, T helper lymphocytes, B lymphocytes, T regulatory cells, and Th17 cells). Cytokine levels in the spleen and hippocampus were determined by enzyme-linked immunosorbent assay (ELISA), and cytokine levels in plasma were performed with MilliPlex® technology. Our results showed that behavioral impairment as measured by the SHIRPA test and elevation in plasma S100ß levels were significant in moderate and severe CLP groups compared to those in the sham control group. Regarding immunological alterations, we were unable to observe changes in the weights of the spleen and the profile of lymphocytes 6 h after CLP. However, several cytokines, including IL-6, IL-10, and IL-1ß, were increased in spleen and plasma. In conclusion, we observed variations in encephalopathy as measured by plasma S100ß, which were mediated by the severity of sepsis; however, we did not observe a different activation of spleen cells 6 h post-CLP, despite evidence of inflammation. Taken together, our data indicate that the severity of sepsis impacts the brain in absence of a change in the spleen lymphocyte profile.
