Silencing suppressor of cytokine signaling 3 induces apoptosis and activates the p-STAT3/NF-κ B pathway in hypoxic cultivated H9c2 cells

Suppressor of cytokine signaling 3 (SOCS3) plays a significant role in the process of myocardial adaptation to chronic hypoxia. SOCS3 finely regulates cell signaling cross-talk that occurs between NF-κB and STAT3 during the compensatory protective response. However, the role and mechanism of SOCS3 in hypoxic cardiomyocytes are not fully understood. In the study, we investigated the effect of SOCS3 on the p65 and STAT3 signaling pathways and further examined the potential molecular mechanism involved in regulating apoptosis. Our data showed that SOCS3 silencing could upregulate Ac-p65, p-p65, and p-STAT3 expression in nuclear extracts of H9c2 cells that received hypoxic treatment for 24, 48, and 72 h. SOCS3 silencing also remarkably increased the DNA-binding activity of the p65 motif in hypoxic cultivated H9c2 cells. We also found that SOCS3 knockdown increased cleaved-caspase-3, Bax, and PUMA expression and decreased cleaved PARP and Bcl-2 in expression in hypoxic H9c2 cells. Silencing of SOCS3 caused an increase in LDH leakage from injured cardiomyocytes and reduced cell viability under conditions of hypoxic stress. Furthermore, SOCS3 silencing enhanced the apoptosis of H9c2 cells at 72 h of hypoxia. These findings suggest that knockdown of SOCS3 leads to excessive activation of the NF-κB pathway, which, in turn, might promote apoptosis under conditions of chronic hypoxia. (AU)

Silencing suppressor of cytokine signaling 3 induces apoptosis and activates the p-STAT3/NF-κ B pathway in hypoxic cultivated H9c2 cells

Suppressor of cytokine signaling 3 (SOCS3) plays a significant role in the process of myocardial adaptation to chronic hypoxia. SOCS3 finely regulates cell signaling cross-talk that occurs between NF-κB and STAT3 during the compensatory protective response. However, the role and mechanism of SOCS3 in hypoxic cardiomyocytes are not fully understood. In the study, we investigated the effect of SOCS3 on the p65 and STAT3 signaling pathways and further examined the potential molecular mechanism involved in regulating apoptosis. Our data showed that SOCS3 silencing could upregulate Ac-p65, p-p65, and p-STAT3 expression in nuclear extracts of H9c2 cells that received hypoxic treatment for 24, 48, and 72 h. SOCS3 silencing also remarkably increased the DNA-binding activity of the p65 motif in hypoxic cultivated H9c2 cells. We also found that SOCS3 knockdown increased cleaved-caspase-3, Bax, and PUMA expression and decreased cleaved PARP and Bcl-2 in expression in hypoxic H9c2 cells. Silencing of SOCS3 caused an increase in LDH leakage from injured cardiomyocytes and reduced cell viability under conditions of hypoxic stress. Furthermore, SOCS3 silencing enhanced the apoptosis of H9c2 cells at 72 h of hypoxia. These findings suggest that knockdown of SOCS3 leads to excessive activation of the NF-κB pathway, which, in turn, might promote apoptosis under conditions of chronic hypoxia. (AU)

AKAP12 promotes cancer stem cell-like phenotypes and activates STAT3 in colorectal cancer

Background Cancer stem cells (CSCs) have unique biological characteristics, including tumorigenicity, immortality, and chemoresistance. Colorectal CSCs have been identified and isolated from colorectal cancers by various methods. AKAP12, a scaffolding protein, is considered to act as a potential suppressor in colorectal cancer, but its role in CSCs remains unknown. In this study, we investigated the function of AKAP12 in Colorectal CSCs. Methods Herein, Colorectal CSCs were enriched by cell culture with a serum-free medium. CSC-associated characteristics were evaluated by Flow cytometry assay and qPCR. AKAP12 gene expression was regulated by lentiviral transfection assay. The tumorigenicity of AKAP12 in vivo by constructing a tumor xenograft model. The related pathways were explored by qPCR and Western blot. Results The depletion of AKAP12 reduced colony formation, sphere formation, and expression of stem cell markers in colorectal cancer cells, while its knockdown decreased the volume and weight of tumor xenografts in vivo. AKAP12 expression levels also affected the expression of stemness markers associated with STAT3, potentially via regulating the expression of protein kinase C. Conclusion This study suggests Colorectal CSCs overexpress AKAP12 and maintain stem cell characteristics through the AKAP12/PKC/STAT3 pathway. AKAP12 may be an important therapeutic target for blocking the development of colorectal cancer in the field of cancer stem cells (AU)

STAT3 inhibitor BBI608 reduces patient-specific primary cell viability of cervical and endometrial cancer at a clinical-relevant concentration

Aberrant activation of STAT3 signal pathway promotes tumor progression in many solid tumor types, including cervical cancer and endometrial cancer. BBI608, the STAT3 inhibitor had been reported in previous studies for restraining cancer stem cells. However, whether BBI608 is available for inhibiting the proliferation of cervical cancer or endometrial cancer remains poorly understood. This study investigated the anti-tumor effect and molecular mechanism of BBI608 on the patient-specific primary cells (PSPC) generated from cervical and endometrial cancer in vitro. Methods PSPCs were obtained from four patients via biopsy. The cell viability was analyzed by the CCK8 assay. The PSPCs were treated with various concentrations of BBI608 or/and paclitaxel; and then, western blot was applied to investigate the expression of phosphorylated STAT3 (pSTAT3). Results The PSPCs cell viability was reduced after treated with BBI608 at a lower concentration. Western blot results showed a reduction trend of pSTAT3 after PSPCs treated with BBI608. Our results demonstrated that BBI608 at the certain concentrations worked well in reducing the cell viability of PSPC from the patients who suffered from cervical cancer and endometrial cancer. Conclusions In this study, the patient-specific primary cell (PSPC) was used as the pre-clinical model for investigating the efficiency of BBI608 in reducing cancer cells viability. BBI608, at a clinical-relevant concentration, had valid efficiency in PSPCs from the patients. The dose of drugs treatment and the measured results were more valuable for further guiding clinical trials (AU)

Tropisetron Ameliorated Cyclophosphamide-Induced Hemorrhagic Cystitis via Restraining TLR-4/NF-kB and JAK1/STAT3 Signaling Pathways

Objective: The main pathological changes of hemorrhagic cystitis (HC) are bladder inflammation, bladder epithelial damage and mast cell infiltration. Tropisetron has been corroborate to conduct a protective role in HC, but its specific etiology remains unclear. The objective of this research was to estimate the mechanism of action of Tropisetron in haemorrhagic cystitis tissue. Methods: Cyclophosphamide (CTX) was utilized to induce the construction of HC rat model, and rats were handled with different doses of Tropisetron. The impact of Tropisetron on the expression of inflammatory factors and oxidative stress factors in the rats with cystitis were measured by western blot, as well as the related proteins of toll-like receptor 4/nuclear transcription factor-κB (TLR-4/NF-κB) and januskinase 1/signal transducer and activator of transcription 3 (JAK1/STAT3) pathways. Results: CTX-induced cystitis in rats was accompanied by notable pathological tissue damage and increased bladder wet weight ratio, elevated mast cell numbers and collagen fibrosis compared to controls. Tropisetron ameliorated CTX-induced injury in a concentration-dependent manner. Futhermore, CTX induced oxidative stress and inflammatory damage, while Tropisetron can alleviate these injuries. Besides, Tropisetron ameliorated CTX-induced cystitis by restraining TLR-4/NF-κB and JAK1/STAT3 signalling pathways. Conclusions: Taken together, Tropisetron ameliorates cyclophosphamide-induced haemorrhagic cystitis via modulating TLR-4/NF-κB and JAK1/STAT3 signalling pathways. These findings carry important implication for the study of the molecular mechanisms of pharmacological treatment of hemorrhagic cystitis (AU)

Deoxyelephantopin alleviates lipopolysaccharide-induced septic lung injury through inhibiting NF-kB/STAT3 axis

Sepsis induces multiple organ dysfunction syndromes, such as acute kidney, liver, or lung injury. Septic lung injury is associated with excessive apoptosis and inflammatory responses in hepatocytes. Deoxyelephantopin is a sesquiterpene lactone found in Elephantopus scaberL, and has immunomodulatory, antibacterial, anti-inflammatory, and antifungal properties. The role of deoxyelephantopin in sepsis-associated lung injury was investigated. First, human bronchial epithelial cells (BEAS-2B) and human pulmonary artery endothelial cells (HPAEC) were treated with lipopolysaccharide to induce cytotoxicity. Treatment with lipopolysac-charide reduced cell viability of BEAS-2B and HPAEC, and promoted cell apoptosis through down-regulation of poly (ADP-ribose) polymerase (PARP) and B-cell lymphoma 2 (Bcl-2), and up-regulation of cleaved PARP and B-cell lymphoma-associated X protein (Bax). Second, lipo-polysaccharide-treated BEAS-2B and HPAEC were incubated with increasing concentrations of deoxyelephantopin, that is, 1, 5, or 10 μM. Deoxyelephantopin enhanced cell viability and reduced cell apoptosis of lipopolysaccharide-treated BEAS-2B and HPAEC. Third, deoxyele-phantopin attenuated lipopolysaccharide-induced decrease of superoxide dismutase and glutathione, and increase of malondialdehyde and myeloperoxidase in BEAS-2B and HPAEC. Moreover, deoxyelephantopin also weakened lipopolysaccharide-induced increase of tumor necrosis factor-α, interleukin (IL)-1β, and IL-6. Finally, deoxyelephantopin decreased pro-tein expression of p-p65 and p-signal transducer and activator of transcription 3 (STAT3) in lipopolysaccharide-treated BEAS-2B and HPAEC. In conclusion, deoxyelephantopin exhibited anti-oxidative and anti-inflammatory effects against lipopolysaccharide-treated BEAS-2B and HPAEC through inactivation of nuclear factor kappa B/STAT3 signaling (AU)

Taxifolin ameliorates sepsis-induced lung capillary leak through inhibiting the JAK/STAT3 pathway

Background As a systemic inflammatory reaction, sepsis is associated with various organ dysfunctions. The capillary leakage and the imbalance between T helper 17 and regulatory T (Th17/Treg) cells are associated with sepsis-induced lung injury. Taxifolin (TXL) has been found to play a vital role in regulating this diverse disease. However, the detailed functioning and mechanism of TXL in regulating sepsis-induced lung capillary leak remain elusive.Methods Balb/c mice were used to establish sepsis-induced lung injury model through administration of lipopolysaccharide (LPS). The structure of lung tissues was observed by using hematoxylin & eosin staining. Protein level and total cells in bronchoalveolar lavage fluid (BALF) were measured by bicinchoninic acid (BCA) protein assay kit and hematimetry assay, respectively. Quantitative real-time reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay were employed to detect the level of inflammatory cytokines. The content of Th17 and Treg cells were measured by flow cytometry analysis. Western blot assay was used to determine the protein level of retinoid-related orphan receptor-γt (RORγt), Forkhead box P3 (Foxp3), Janus kinase 2 (JAK2), phospho(p)-JAK2, signal transducer and activator of transcription 3 (STAT3), and phospho(p)-STAT3.Results Taxifolin effectively prolonged the survival period of sepsis mice and alleviated LPS-induced lung injury in a dose-dependent manner. Moreover, TXL reduced LPS-induced increase in protein levels and T cell content in BALF, and effectively restored the wet:dry ratio of lung tissue and tissue permeability. Treating with TXL notably inhibited the production of pro-inflammatory cytokines induced by sepsis and influenced the balance between Th17 and Treg cells. Furthermore, TXL treatment suppressed the activation of JAK/STAT3 signaling pathway in a dose-dependent manner (AU)

Aberrantly low STAT3 and STAT5 responses are associated with poor outcome and an inflammatory gene expression signature in pediatric acute myeloid leukemia

The relapse rate for children with acute myeloid leukemia is nearly 40% despite aggressive chemotherapy and often stem cell transplant. We sought to understand how environment-induced signaling responses are associated with clinical response to treatment. We previously reported that patients whose AML cells showed low G-CSF-induced STAT3 activation had inferior event-free survival compared to patients with stronger STAT3 responses. Here, we expanded the paradigm to evaluate multiple signaling parameters induced by a more physiological stimulus. We measured STAT3, STAT5 and ERK1/2 responses to G-CSF and to stromal cell-conditioned medium for 113 patients enrolled on COG trials AAML03P1 and AAML0531. Low inducible STAT3 activity was independently associated with inferior event-free survival in multivariate analyses. For inducible STAT5 activity, those with the lowest and highest responses had inferior event-free survival, compared to patients with intermediate STAT5 responses. Using existing RNA-sequencing data, we compared gene expression profiles for patients with low inducible STAT3/5 activation with those for patients with higher inducible STAT3/5 signaling. Genes encoding hematopoietic factors and mitochondrial respiratory chain subunits were overexpressed in the low STAT3/5 response groups, implicating inflammatory and metabolic pathways as potential mechanisms of chemotherapy resistance. We validated the prognostic relevance of individual genes from the low STAT3/5 response signature in a large independent cohort of pediatric AML patients. These findings provide novel insights into interactions between AML cells and the microenvironment that are associated with treatment failure and could be targeted for therapeutic interventions (AU)

Propofol inhibited gastric cancer proliferation via the hsa-miR-328-3p/STAT3 pathway

Purpose The aim of the present study was to elucidate the functional role of hsa-miR-328-3p/STAT3 pathway in the effects of propofol on gastric cancer proliferation. Methods Bioinformatics was used to analyze the molecular expression differences of hsa-miR-328-3p/STAT3 axis in stomach adenocarcinoma (n = 435) and normal samples (n = 41) from TCGA database. The expression of the above molecules in gastric cancer cells SGC-7901 and normal gastric mucosal cells GES-1 was verified via qPCR. The dual-luciferase assay was carried out to confirm the interaction between hsa-miR-328-3p and STAT3. Subsequently, the cell proliferation and the expression of the above molecules in SGC-7901 and GES-1 cells were evaluated after 10 μM propofol treatment. Finally, we analyzed whether propofol still inhibited the proliferation of gastric cancer by suppressing STAT3 pathway after hsa-miR-328-3p down-regulation. Results Compared with normal samples, the expression of hsa-miR-328-3p was significantly down-regulated in stomach adenocarcinoma samples, while the expression of STAT3 and downstream target genes (MMP2, CCND1 and COX2) was up-regulated. The results were consistent with those in GES-1 and SGC-7901 cell lines. Meanwhile, we found that hsa-miR-328-3p can bind to the 3′-UTR of the potential target gene STAT3. Furthermore, propofol significantly inhibited the proliferation of gastric cancer cell line SGC-7901, where hsa-miR-328-3p was up-regulated and the expression of STAT3 and downstream proliferation-related target genes were down-regulated. However, the growth inhibition of propofol on SGC-7901 cell was significantly reversed after the inhibition of hsa-miR-328-3p. Conclusions To sum up, propofol suppressed the STAT3 pathway via up-regulating hsa-miR-328-3p to inhibit gastric cancer proliferation (AU)

Análisis de la expresión nuclear de pSer727-STAT3 como factor pronóstico en pacientes con carcinoma renal de células claras / Analysis of the nuclear expression of pSer727-STAT3 as a prognostic factor in patients with clear cell renal carcinoma

INTRODUCCIÓN: Actualmente no existe ningún marcador pronóstico para el carcinoma renal de células claras (CRCC). La proteína STAT3 (Signal Transducer and Activator of Transcription 3) está implicada en la carcinogénesis del CRCC. Su activación se produce mediante fosforilación del residuo serina 727, translocándose al núcleo donde participa en la carcinogénesis y progresión tumoral. El objetivo primario del estudio fue evaluar la supervivencia cáncer-específica en una serie de 166 pacientes afectos de CRCC, y su posterior correlación con la expresión de pSer727-STAT3 como marcador pronóstico de CRCC. MATERIAL Y MÉTODOS: Realizamos un estudio retrospectivo en 166 pacientes con CRCC intervenidos mediante nefrectomía parcial o radical entre 2000 y 2010. Se construyó un microarray de tejido tumoral y se analizó la expresión inmunohistoquímica de pSer727-STAT3. La variable principal del estudio fue la supervivencia cáncer-específica. RESULTADOS: El grupo de riesgo según la UICC fue en 78 pacientes (47%) bajo, en 52 (31,3%) intermedio y en 36 (21,7%) alto; 11 pacientes (6,7%) debutaron con enfermedad metastásica. Durante un seguimiento medio de 97,2 meses (1-208), 37 pacientes (22,3%) desarrollaron recurrencia local y/o a distancia. La mortalidad cáncer-específica fue del 28,3% y la mortalidad global del 67,5%. La expresión media de pSer727-STAT3 fue de 92,9 (IC 95%:84,6-101,1) sin observarse relación con grupos de riesgo u otros factores pronósticos. En un análisis de regresión logística de Cox, pSer727-STAT3 no se comportó como un predictor independiente de mortalidad cáncer-específica. Sin embargo, en pacientes de alto riesgo y metastásicos, la supervivencia cáncer-específica fue significativamente mayor cuando la expresión de pSer727-STAT3 fue inferior a 110, HR: 5,4 (IC 96%:1,8-16,4) y HR: 2,3 (IC 95%: 1,1-4,6) respectivamente, p > 0,001. CONCLUSIONES: pSer727-STAT3 no es un marcador de supervivencia en los pacientes con CRCC. Sin embargo, en pacientes de alto riesgo, es un marcador de supervivencia cáncer-específica, incluso en pacientes metastásicos que reciben tratamiento con antiangiogénicos

INTRODUCTION: Currently, clear cell renal carcinoma (CCRCC) has no prognostic markers. STAT3 protein (Signal Transducer and Activator of Transcription 3) is involved in the carcinogenesis of CCRCC. Its activation is produced by phosphorylation of the serine 727 residue, translocating to the nucleus where it is involved in carcinogenesis and tumor progression. The primary objective of the study was to evaluate cancer-specific survival rates in a series of 166 patients with CCRCC, and its subsequent correlation with the expression of pSer727-STAT3 as a prognostic marker of CCRCC. MATERIAL AND METHODS: We conducted a retrospective study on 166 patients with CCRCC undergoing partial or radical nephrectomy between 2000 and 2010. A tumor tissue microarray was constructed for immunohistochemical analysis of pSer727-STAT3 expression. The main variable of the study was cancer-specific survival. RESULTS: Patients were classified according to the UICC risk groups as follows: low in 78 patients (47%), intermediate in 52 (31.3%) and high 36 (21.7%); 11 patients (6.7%) were diagnosed with metastatic disease. During a mean follow-up of 97.2 months (1-208), 37 patients (22.3%) developed local and/or distant recurrence. Cancer-specific and overall mortality rates were 28.3% and 67.5%, respectively. The mean expression of pSer727-STAT3 was 92.9 (95% CI: 84.6-101.1) without showing any relationship with risk groups or other prognostic factors. In a Cox logistic regression analysis, pSer727-STAT3 did not behave as an independent predictor of cancer-specific mortality. However, in high-risk and metastatic patients, cancer-specific survival was significantly higher when the expression of pSer727-STAT3 was lower than 110, HR: 5.4 (96% CI: 1.8-16.4) and HR: 2.3 (95% CI: 1.1-4.6) respectively, P<.001. CONCLUSIONS: pSer727-STAT3 is not a survival marker in patients with CCRCC. However, it is a cancer-specific survival marker in high-risk patients, even in metastatic patients undergoing treatment with antiangiogenic agents

Phenotyping and long-term follow up of patients with hyper IgE syndrome

Introduction and objectives: Long-term follow up of patients with hyper IgE syndrome (HIES), as a primary immunodeficiency disorder, has been poorly investigated. This study describes common clinical and immunological features of patients with HIES in the last 10 years in Shiraz University of Medical Sciences, Shiraz, Iran. Methods and patients: In this cross-sectional study, the symptoms and medical records of 18 patients, who were diagnosed with HIES, were observed. Genetic and immunologic study was also performed. Results: Eighteen patients with the mean age of 13 years old were investigated. Ten patients were detected to have mutations in DOCK8 gene and autosomal recessive HIES (AR-HIES); and four patients were found with STAT3 mutation and autosomal dominant HIES (AD-HIES). So, 14 patients with known genetic results were considered for further data analysis. Food allergy, eczema, viral and skin infections were the major complications of AR-HIES patients. The major clinical complications of AD-HIES patients were pneumonia, skin infections and eczema. Food allergy and viral infection were significantly higher in DOCK8 deficient patients. The most common causes of hospitalization in both AR-HIES and AD-HIES patients were pneumonia, skin infections and sepsis. The most common cause of death was found to be sepsis. Conclusions; AD-HIES and AR-HIES cannot be differentiated only based on the clinical presentations. Genetic features are also necessary for better diagnosis. This study, summarizing the clinical, immunological and genetic information of the patients with AD-HIES and AR-HIES, may open a way for better diagnosis and management of HIES

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Valor de la proteína STAT3 como factor pronóstico en el carcinoma renal de célula clara. Revisión sistemática / The role of STAT3 protein as a prognostic factor in the clear cell renal carcinoma. Systematic review

Contexto y objetivo: En los últimos años se han producido avances significativos en el conocimiento de la carcinogénesis renal. Hoy en día los tumores renales se clasifican en función de su perfil genético, y además se han desarrollado tratamientos específicos basados en la identificación de dianas terapéuticas. Sin embargo, todavía no se han identificado marcadores pronósticos. El objetivo de esta revisión es analizar la literatura que ha evaluado la expresión de la proteína STAT3 como marcador molecular en el carcinoma renal de célula clara (ccRCC). Adquisición de evidencia: En enero de 2018 se realizó una búsqueda sistemática de la literatura en Pubmed, Cochrane Library y Sciencedirect de las publicaciones realizadas desde 1990. Los términos de búsqueda fueron renal cell carcinoma and STAT3 or STAT-3 and prognostic factor. Se siguieron los principios de la declaración PRISMA y la estrategia de selección PICO, seleccionándose los artículos originales con series de pacientes diagnosticados de ccRCC localizado o metastásico, donde se analiza la actividad de STAT3 como marcador pronóstico. Se identificaron 132 publicaciones de las que finalmente se han revisado 10 por cumplir los criterios de inclusión. Síntesis de evidencia: La activación (fosforilación) de STAT3 (pSTAT3) en el residuo Ser727 es importante en el desarrollo y progresión de ccRCC. La expresión de pSTAT3 parece ser un marcador pronóstico y predictor de resistencia a algunos tratamientos en pacientes con enfermedad diseminada. Existe poca evidencia de su utilidad como un marcador pronóstico en pacientes con enfermedad localizada. Conclusiones: La expresión de pSTAT3(Ser727) en el núcleo de las células del ccRCC puede ser un marcador pronóstico y de respuesta al tratamiento en pacientes con ccRCC. La evidencia científica actual es limitada y son necesarios más estudios que demuestren su utilidad

Context and objective: There have been significant advances in the knowledge of renal carcinogenesis in the last years. Nowadays, renal tumours are classified according to their genetic profile and specific treatments based on the identification of therapeutic targets have also been developed. However, no prognostic markers have yet been identified. The aim of this review is to analyze literature that has evaluated the expression of the STAT3 protein as a molecular marker in clear cell renal carcinoma (ccRCC). Evidence acquisition: In January 2018 a systematic review was conducted in Pubmed, Cochrane library and Sciencedirect databases, from papers published from 1990. Search terms were "renal cell carcinoma" and "STAT3" or "STAT-3" and prognostic factor. Following the principles of the PRISMA declaration and the PICO selection strategy, original articles with series of patients diagnosed with localized or metastatic ccRCC, and where the activity of STAT3 is analyzed as a prognostic marker, were selected. A total of 132 publications were identified, of which 10 were finally revised, for they met the inclusion criteria. Evidence synthesis: STAT3 activation (phosphorylation) through Ser727 is important during ccRCC development and progression. PSTAT3 expression seems to be a prognostic marker and an antiangiogenic-resistance marker in metastatic patients. There is little evidence as prognostic marker in patients with localized disease. Conclusions: STAT3 (Ser 727) expression in the nucleus of the ccRCC cells can be a prognostic marker and an antiangiogenic-resistance marker. Current scientific evidence is limited and more studies are needed to demonstrate its usefulness

Leptin drives fat distribution during diet-induced obesity in mice

Objective Desensitization of leptin receptors is a process that specifically occurs in some tissues. We have hypothesized that during the development of obesity tissue lipids would increase gradually in particular organs depending on leptin responsiveness. Our aim was to establish a relationship between leptin resistance and lipid deposition by using a model of diet-induced obesity (DIO) and we have characterized, in mice undergoing a dietary treatment with a high-fat (HF) diet, the evolution of lipid content and leptin responsiveness in white adipose tissue and liver. Methods Four-week-old male C57BL/6J mice were divided into two groups and assigned either to a low-fat or to a high-fat diet. Dietary treatment lasted 8, 20 or 32 weeks. The last day animals received 1mg/kg leptin and then tissues were weighed and processed for Western-blotting and lipid determination. Results We observed an initial increase of the relative weight of adipose pads that was blunted after 32-week HF. In contrast, liver size exhibited an initial decrease followed by a progressive increase, which was coincident with the increase of hepatic triglycerides and with the impairment of leptin receptor signalling. Conclusion Our data show that leptin resistance within white adipose tissue does not deal with an increase of the size of adipose pads and suggest that consequences of leptin resistance, in terms of fat accumulation, are tissue-dependent (AU)

Objetivo La desensibilización de los receptores de la leptina es un proceso que ocurre de forma específica en algunos tejidos. Comprobamos la hipótesis de si durante el desarrollo de la obesidad, aumentarían los lípidos en tejido de forma progresiva en órganos concretos y en función de la capacidad de respuesta a la leptina. Nuestro objetivo fue establecer una relación entre la resistencia a la leptina y la deposición de lípidos mediante el uso de un modelo de obesidad inducida por dieta (OID) y caracterizamos, en ratones sometidos a un tratamiento dietético con una dieta elevada en grasas (DEG), la evolución del contenido lipídico y la capacidad de respuesta a la leptina en tejido adiposo blanco y en el hígado. Métodos Ratones C57BL/6J machos de cuatro semanas de edad fueron divididos en dos grupos y asignados a una dieta de bajo o de elevado contenido en grasas. El tratamiento dietético duró 8, 20 o 32 semanas. El último día, los animales recibieron 1mg / kg de leptina y luego se pesaron y se procesaron los tejidos para transferencia de tipo Western y la determinación de lípidos. Resultados Se observó un aumento inicial en el peso relativo del tejido adiposo, que se redujo después de 32 semanas con DEG. Por otro lado, el tamaño del hígado mostró una descenso inicial, seguido de un aumento progresivo que coincidió con un aumento de los triglicéridos hepáticos y un deterioro en la señalización del receptor de la leptina. Conclusión Nuestros datos muestran que la resistencia a la leptina en el tejido adiposo blanco no aborda un aumento de tamaño del tejido adiposo y sugiere que las consecuencias de la resistencia a la leptina, en términos de acumulación de grasa, dependen del tejido (AU)

Tissue microarray-based study of patients with lymph node-positive breast cancer shows tyrosine phosphorylation of signal transducer and activator of transcription 3 (tyrosine705-STAT3) is a marker of good prognosis

BACKGROUND: Although lymph node-positive breast cancers are associated with poorer prognosis, individual patients may have different clinical outcomes. Signal transducer and activator of transcription 3 (STAT3) is a point of convergence for numerous oncogenic signalling pathways. The goal of this study was to determine the prognostic value of phosphorylated (tyrosine705)-STAT3 in node-positive breast cancer patients. METHODS: Immunohistochemical analysis of Phospho- STAT3 was performed on a tissue microarray of breast cancer specimens. The expression pattern of Phospho-STAT3 was correlated with survival outcome, and clinical and pathological parameters. RESULTS: Out of 125 interpretable tumours, positive Phospho- STAT3 nuclear expression was seen in 35 (28%) of tumours. There was no significant relationship between Phospho-STAT3 expression and clinical-pathological parameters including age, hormonal receptor status, grade and tumour size. Interestingly positive tumours had a significantly improved disease-free survival at 5 years (p=0.035). Additionally, positive Phospho-STAT3 nuclear expression was correlated with significantly improved survival at both 5 years (p=0.023) and 10 years (p=0.026). Finally, in multivariate analyses Phospho-STAT3 was found to be an independent prognostic marker of overall survival in node-positive breast cancer patients. CONCLUSION: These findings support the role of Phospho- STAT3 as an important independent prognostic marker in node-positive breast cancer patients (AU)

JAK/STAT signal pathway activation promotes progression and survival of human oesophageal squamous cell carcinoma

OBJECTIVE: Inappropriate activation of JAK/STAT pathway occurs with high frequency in human cancers and is associated with cancer cell survival and proliferation. However, its role in oesophageal squamous cell carcinoma (ESCC) is unknown. METHODS: By immunohistochemistry, we analysed the expression of two components of this pathway, phosphorylated JAK-1 (pJAK-1) and phosphorylated STAT-3 (pSTAT-3), in 100 ESCC tumours and paired non-neoplastic oesophageal epithelia. Kaplan-Meier survival and Cox regression analyses were performed to evaluate the prognosis of patients. RESULTS: We found that pJAK-1 and pSTAT-3 expression was not detectable in normal oesophageal squamous cells. Primary ESCC with pJAK-1-positive and pSTAT-3-positive expression was detected in the cancer cell nests of 78 and 72 cases, respectively. In addition, the Pearson's correlation coefficient between pJAK-1 and pSTAT-3 expression was 0.806 (p<0.001). Moreover, pJAK-1 and pSTAT-3 expression was correlated with N stage (lymph node metastasis, both p=0.01), pTNM stage (p=0.008 and 0.009, respectively) and metastatic status (both p=0.01). Furthermore, pJAK-1 and pSTAT-3 expression was associated with shorter overall survival (both p<0.001) and shorter disease-free survival (p=0.005 and 0.006, respectively). By multivariate analysis, TNM clinical classification (T, p<0.001; N, p=0.002; M, p=0.02), pJAK-1 (p=0.002) and pSTAT-3 (p=0.003) were independent prognosis predictors of ESCC. CONCLUSION: These results provide convincing evidence for the first time that the JAK/STAT pathway may participate in the progress of ESCC (AU)