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Sample records for boosts stat3 activation

  1. The combination of IL-21 and IFN-alpha boosts STAT3 activation, cytotoxicity and experimental tumor therapy

    DEFF Research Database (Denmark)

    Eriksen, Karsten W; Søndergaard, Henrik; Woetmann, Anders;

    2008-01-01

    such as IFN-alpha and IL-2 have multiple and severe side effects. Accordingly, they are generally used at sub-optimal doses, which limit their clinical efficacy. Here we hypothesized that a combination of IFN-alpha and IL-21, a novel cytokine of the IL-2 family with anti-cancer effects, will increase the anti......-cancer efficacy at sub-optimal cytokine doses. We show that the combined stimulation of target-cells with IFN-alpha and IL-21 triggers an increased STAT3 activation whereas the activation of other STATs including STAT1/2 is unaffected. In parallel, the combined stimulation with IFN-alpha and IL-21 triggers...... a selective increase in MHC class I expression and NK- and CD8(+) T-cell-mediated cytotoxicity. In an experimental in vivo model of renal carcinoma, the combined treatment of IFN-alpha and IL-21 also produces a significant anti-cancer effect as judged by an inhibition of tumor growth and an increased survival...

  2. Eriocalyxin B Inhibits STAT3 Signaling by Covalently Targeting STAT3 and Blocking Phosphorylation and Activation of STAT3.

    Directory of Open Access Journals (Sweden)

    Xiaokui Yu

    Full Text Available Activated STAT3 plays an important role in oncogenesis by stimulating cell proliferation and resisting apoptosis. STAT3 therefore is an attractive target for cancer therapy. We have screened a traditional Chinese herb medicine compound library and found Eriocalyxin B (EB, a diterpenoid from Isodon eriocalyx, as a specific inhibitor of STAT3. EB selectively inhibited constitutive as well as IL-6-induced phosphorylation of STAT3 and induced apoptosis of STAT3-dependent tumor cells. EB did not affect the upstream protein tyrosine kinases or the phosphatase (PTPase of STAT3, but rather interacted directly with STAT3. The effects of EB could be abolished by DTT or GSH, suggesting a thiol-mediated covalent linkage between EB and STAT3. Site mutagenesis of cysteine in and near the SH2 domain of STAT3 identified Cys712 to be the critical amino acid for the EB-induced inactivation of STAT3. Furthermore, LC/MS/MS analyses demonstrated that an α, β-unsaturated carbonyl of EB covalently interacted with the Cys712 of STAT3. Computational modeling analyses also supported a direct interaction between EB and the Cys712 of STAT3. These data strongly suggest that EB directly targets STAT3 through a covalent linkage to inhibit the phosphorylation and activation of STAT3 and induces apoptosis of STAT3-dependent tumor cells.

  3. STAT3 Activities and Energy Metabolism: Dangerous Liaisons

    Energy Technology Data Exchange (ETDEWEB)

    Camporeale, Annalisa, E-mail: annalisa.camporeale@unito.it [Molecular Biotechnology Center and Department of Molecular Biotechnology and Life Sciences, University of Turin, Via Nizza 52, Turin 10126 (Italy); Demaria, Marco [Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945 (United States); Monteleone, Emanuele [Molecular Biotechnology Center and Department of Molecular Biotechnology and Life Sciences, University of Turin, Via Nizza 52, Turin 10126 (Italy); Giorgi, Carlotta [Department of Experimental and Diagnostic Medicine, Section of General Pathology, Laboratory for Technologies of Advances Therapies (LTTA), University of Ferrara, Via Fossato di Mortara 70, Ferrara 44121 (Italy); Wieckowski, Mariusz R. [Nencki Institute of Experimental Biology, Department of Biochemistry, Pasteur Str. 3, Warsaw 02-093 (Poland); Pinton, Paolo [Department of Experimental and Diagnostic Medicine, Section of General Pathology, Laboratory for Technologies of Advances Therapies (LTTA), University of Ferrara, Via Fossato di Mortara 70, Ferrara 44121 (Italy); Poli, Valeria, E-mail: annalisa.camporeale@unito.it [Molecular Biotechnology Center and Department of Molecular Biotechnology and Life Sciences, University of Turin, Via Nizza 52, Turin 10126 (Italy)

    2014-07-31

    STAT3 mediates cytokine and growth factor receptor signalling, becoming transcriptionally active upon tyrosine 705 phosphorylation (Y-P). Constitutively Y-P STAT3 is observed in many tumors that become addicted to its activity, and STAT3 transcriptional activation is required for tumor transformation downstream of several oncogenes. We have recently demonstrated that constitutively active STAT3 drives a metabolic switch towards aerobic glycolysis through the transcriptional induction of Hif-1α and the down-regulation of mitochondrial activity, in both MEF cells expressing constitutively active STAT3 (Stat3{sup C/C}) and STAT3-addicted tumor cells. This novel metabolic function is likely involved in mediating pre-oncogenic features in the primary Stat3{sup C/C} MEFs such as resistance to apoptosis and senescence and rapid proliferation. Moreover, it strongly contributes to the ability of primary Stat3{sup C/C} MEFs to undergo malignant transformation upon spontaneous immortalization, a feature that may explain the well known causative link between STAT3 constitutive activity and tumor transformation under chronic inflammatory conditions. Taken together with the recently uncovered role of STAT3 in regulating energy metabolism from within the mitochondrion when phosphorylated on Ser 727, these data place STAT3 at the center of a hub regulating energy metabolism under different conditions, in most cases promoting cell survival, proliferation and malignant transformation even though with distinct mechanisms.

  4. STAT3 activation in monocytes accelerates liver cancer progression

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    Wu Wen-Yong

    2011-12-01

    Full Text Available Abstract Background Signal transducer and activator of transcription 3 (STAT3 is an important transcription factor ubiquitously expressed in different cell types. STAT3 plays an essential role in cell survival, proliferation, and differentiation. Aberrantly hyper-activated STAT3 signaling in cancer cells and in the tumor microenvironment has been detected in a wide variety of human cancers and is considered an important factor for cancer initiation, development, and progression. However, the role of STAT3 activation in monocytes in the development of HCC has not been well understood. Methods Immunohistochemical analysis of phosphorylated STAT3 was performed on tissue microarray from HCC patients. Using a co-culture system in vivo, HCC cell growth was determined by the MTT assay. In vivo experiments were conducted with mice given diethylinitrosamine (DEN, which induces HCC was used to investigate the role of STAT3 expression in monocytes on tumor growth. Real-time PCR was used to determine the expression of cell proliferation and cell arrest associated genes in the tumor and nontumor tissue from liver. Results Phosphorylated STAT3 was found in human hepatocellular carcinoma tissue samples and was expressed in tumor cells and also in monocytes. Phosphorylated STAT3 expression in monocyte was significantly correlated to advanced clinical stage of HCC and a poor prognosis. Using a co-culture system in vivo, monocytes promoted HCC cell growth via the IL-6/STAT3 signaling pathway. The STAT3 inhibitor, NSC 74859, significantly suppressed tumor growth in vivo in mice with diethylinitrosamine (DEN-induced HCC. In this animal model, blockade of STAT3 with NSC 74859 induced tumor cell apoptosis, while inhibiting both tumor cells and monocytes proliferation. Furthermore, NSC 74859 treatment suppressed cancer associated inflammation in DEN-induce HCC. Conclusion Our data suggest constitutively activated STAT3 monocytes promote liver tumorigenesis in clinical

  5. STAT3 activation in monocytes accelerates liver cancer progression

    International Nuclear Information System (INIS)

    Signal transducer and activator of transcription 3 (STAT3) is an important transcription factor ubiquitously expressed in different cell types. STAT3 plays an essential role in cell survival, proliferation, and differentiation. Aberrantly hyper-activated STAT3 signaling in cancer cells and in the tumor microenvironment has been detected in a wide variety of human cancers and is considered an important factor for cancer initiation, development, and progression. However, the role of STAT3 activation in monocytes in the development of HCC has not been well understood. Immunohistochemical analysis of phosphorylated STAT3 was performed on tissue microarray from HCC patients. Using a co-culture system in vivo, HCC cell growth was determined by the MTT assay. In vivo experiments were conducted with mice given diethylinitrosamine (DEN), which induces HCC was used to investigate the role of STAT3 expression in monocytes on tumor growth. Real-time PCR was used to determine the expression of cell proliferation and cell arrest associated genes in the tumor and nontumor tissue from liver. Phosphorylated STAT3 was found in human hepatocellular carcinoma tissue samples and was expressed in tumor cells and also in monocytes. Phosphorylated STAT3 expression in monocyte was significantly correlated to advanced clinical stage of HCC and a poor prognosis. Using a co-culture system in vivo, monocytes promoted HCC cell growth via the IL-6/STAT3 signaling pathway. The STAT3 inhibitor, NSC 74859, significantly suppressed tumor growth in vivo in mice with diethylinitrosamine (DEN)-induced HCC. In this animal model, blockade of STAT3 with NSC 74859 induced tumor cell apoptosis, while inhibiting both tumor cells and monocytes proliferation. Furthermore, NSC 74859 treatment suppressed cancer associated inflammation in DEN-induce HCC. Our data suggest constitutively activated STAT3 monocytes promote liver tumorigenesis in clinical patients and animal experiments. Thus, STAT3 in tumor

  6. Targeting STAT3 in Ovarian Cancers: Reciprocal Activation of NF-kB by STAT3 Inhibition

    OpenAIRE

    Zhang, Yixi

    2016-01-01

    The transcription factor STAT3 normally modulates cell proliferation with a rapid and transient downstream effect. However, in tumor cells, inappropriately activated STAT3 alters the gene expression profile and renders tumor cells unresponsive to cell death signals. In this study, we examine the biological and biochemical effects of some STAT3 inhibitors on ovarian and cervical cancer cells. Furthermore, we study the reciprocal relationship between STAT3 and NF-kB—another prosurvival transcr...

  7. Activation of Hepatic STAT3 Maintains Pulmonary Defense during Endotoxemia.

    Science.gov (United States)

    Hilliard, Kristie L; Allen, Eri; Traber, Katrina E; Kim, Yuri; Wasserman, Gregory A; Jones, Matthew R; Mizgerd, Joseph P; Quinton, Lee J

    2015-10-01

    Pneumonia and infection-induced sepsis are worldwide public health concerns. Both pathologies elicit systemic inflammation and induce a robust acute-phase response (APR). Although APR activation is well regarded as a hallmark of infection, the direct contributions of liver activation to pulmonary defense during sepsis remain unclear. By targeting STAT3-dependent acute-phase changes in the liver, we evaluated the role of liver STAT3 activity in promoting host defense in the context of sepsis and pneumonia. We employed a two-hit endotoxemia/pneumonia model, whereby administration of 18 h of intraperitoneal lipopolysaccharide (LPS; 5 mg/kg of body weight) was followed by intratracheal Escherichia coli (10(6) CFU) in wild-type mice or those lacking hepatocyte STAT3 (hepSTAT3(-/-)). Pneumonia alone (without endotoxemia) was effectively controlled in the absence of liver STAT3. Following endotoxemia and pneumonia, however, hepSTAT3(-/-) mice, with significantly reduced levels of circulating and airspace acute-phase proteins, exhibited significantly elevated lung and blood bacterial burdens and mortality. These data suggested that STAT3-dependent liver responses are necessary to promote host defense. While neither recruited airspace neutrophils nor lung injury was altered in endotoxemic hepSTAT3(-/-) mice, alveolar macrophage reactive oxygen species generation was significantly decreased. Additionally, bronchoalveolar lavage fluid from this group of hepSTAT3(-/-) mice allowed greater bacterial growth ex vivo. These results suggest that hepatic STAT3 activation promotes both cellular and humoral lung defenses. Taken together, induction of liver STAT3-dependent gene expression programs is essential to countering the deleterious consequences of sepsis on pneumonia susceptibility. PMID:26216424

  8. Inhibition of STAT3 reduces astrocytoma cell invasion and constitutive activation of STAT3 predicts poor prognosis in human astrocytoma.

    Directory of Open Access Journals (Sweden)

    Qinchuan Liang

    Full Text Available Astrocytoma cells characteristically possess high invasion potentials. Recent studies have revealed that knockdown of signal transducers and activators of transcription 3 (STAT3 expression by RNAi induces apoptosis in astrocytoma cell. Nevertheless, the distinct roles of STAT3 in astrocytoma's invasion and recurrence have not been elucidated. In this study, we silenced STAT3 using Small interfering RNAs in two human glioblastoma multiforme (GBM cell lines (U251 and U87, and investigated the effect on GBM cell adhesion and invasion. Our results demonstrate that disruption of STAT3 inhibits GBM cell's adhesion and invasion. Knockdown of STAT3 significantly increased E-cadherin but decreased N-cadherin, vascular endothelial growth factor, matrix metalloproteinase 2 and matrix metalloproteinase 9. Additionally, expression of pSTAT3(Tyr705 correlates with astrocytoma WHO classification, Karnofsky performance status scale score, tumor recurrence and survival. Furthermore, pSTAT3(Tyr705 is a significant prognostic factor in astrocytoma. In conclusion, STAT3 may affect astrocytoma invasion, expression of pSTAT3(Tyr705 is a significant prognostic factor in tumor recurrence and overall survival in astrocytoma patients. Therefore, STAT3 may provide a potential target for molecular therapy in human astrocytoma, and pSTAT3(Tyr705could be an important biomarker for astrocytoma prognosis.

  9. STAT3 Activation in Glioblastoma: Biochemical and Therapeutic Implications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jennifer E.; Patel, Mira; Ruzevick, Jacob; Jackson, Christopher M.; Lim, Michael, E-mail: mlim3@jhmi.edu [Department of Neurosurgery, The Johns Hopkins University School of Medicine, 600 N. Wolfe St., Phipps Building Rm 123, Baltimore, MD 21287 (United States)

    2014-02-10

    Signal transducer and activator of transcription 3 (STAT3) is a potent regulator of gliomagenesis through its induction of angiogenesis, host immunosuppression, and tumor invasion. Gain of function mutations result in constitutive activation of STAT3 in glioma cells, making STAT3 an attractive target for inhibition in cancer therapy. Nevertheless, some studies show that STAT3 also participates in terminal differentiation and apoptosis of various cell lines and in glioma with phosphatase and tensin homolog (PTEN)-deficient genetic backgrounds. In light of these findings, the utility of STAT3 as a prognostic indicator and as a target of drug therapies will be contingent on a more nuanced understanding of its pro- and anti-tumorigenic effects.

  10. Inhibition of STAT3 Reduces Astrocytoma Cell Invasion and Constitutive Activation of STAT3 Predicts Poor Prognosis in Human Astrocytoma

    OpenAIRE

    Qinchuan Liang; Chenkai Ma; Yang Zhao; Guodong Gao; Jie Ma

    2013-01-01

    Astrocytoma cells characteristically possess high invasion potentials. Recent studies have revealed that knockdown of signal transducers and activators of transcription 3 (STAT3) expression by RNAi induces apoptosis in astrocytoma cell. Nevertheless, the distinct roles of STAT3 in astrocytoma's invasion and recurrence have not been elucidated. In this study, we silenced STAT3 using Small interfering RNAs in two human glioblastoma multiforme (GBM) cell lines (U251 and U87), and investigated th...

  11. Activation of Hepatic STAT3 Maintains Pulmonary Defense during Endotoxemia

    OpenAIRE

    Hilliard, Kristie L.; Allen, Eri; Traber, Katrina E.; Kim, Yuri; Wasserman, Gregory A.; Jones, Matthew R.; Mizgerd, Joseph P.; Quinton, Lee J.

    2015-01-01

    Pneumonia and infection-induced sepsis are worldwide public health concerns. Both pathologies elicit systemic inflammation and induce a robust acute-phase response (APR). Although APR activation is well regarded as a hallmark of infection, the direct contributions of liver activation to pulmonary defense during sepsis remain unclear. By targeting STAT3-dependent acute-phase changes in the liver, we evaluated the role of liver STAT3 activity in promoting host defense in the context of sepsis a...

  12. Activation of oligodendroglial Stat3 is required for efficient remyelination

    Science.gov (United States)

    Steelman, Andrew J.; Zhou, Yun; Koit, Hisami; Kim, SunJa; Payne, H. Ross; Lu, Q. Richard; Li, Jianrong

    2016-01-01

    Multiple sclerosis is the most prevalent demyelinating disease of the central nervous system (CNS) and is histologically characterized by perivascular demyelination as well as neurodegeneration. While the degree of axonal damage is correlated with clinical disability, it is believed that remyelination can protect axons from degeneration and slow disease progression. Therefore, understanding the intricacies associated with myelination and remyelination may lead to therapeutics that can enhance the remyelination process and slow axon degeneration and loss of function. Ciliary neurotrophic factor (CNTF) family cytokines such as leukemia inhibitory factor (LIF) and interleukin11(IL-11) are known to promote oligodendrocyte maturation and remyelination in experimental models of demyelination. Because CNTF family member binding to the gp 130 receptor results in activation of the JAK2/Stat3 pathway we investigated the necessity of oligodendroglial Stat3 in transducing the signal required for myelination and remyelination. We found that Stat3 activation in the CNS coincides with myelination during development. Stimulation of oligodendrocyte precursor cells (OPCs) with CNTF or LIF promoted OPC survival and final differentiation, which was completely abolished by pharmacologic blockade of Stat3 activation with JAK2 inhibitor. Similarly, genetic ablation of Stat3 in oligodendrocyte lineage cells prevented CNTF-induced OPC differentiation in culture. In vivo, while oligodendroglial Stat3 signaling appears to be dispensable for developmental CNS myelination, it is required for oligodendrocyte regeneration and efficient remyelination after toxin-induced focal demyelination in the adult brain. Our data suggest a critical function for oligodendroglial Stat3 signaling in myelin repair. PMID:27060559

  13. Activating STAT3 Alpha for Promoting Healing of Neurons

    Science.gov (United States)

    Conway, Greg

    2008-01-01

    A method of promoting healing of injured or diseased neurons involves pharmacological activation of the STAT3 alpha protein. Usually, injured or diseased neurons heal incompletely or not at all for two reasons: (1) they are susceptible to apoptosis (cell death); and (2) they fail to engage in axogenesis that is, they fail to re-extend their axons to their original targets (e.g., muscles or other neurons) because of insufficiency of compounds, denoted neurotrophic factors, needed to stimulate such extension. The present method (see figure) of treatment takes advantage of prior research findings to the effect that the STAT3 alpha protein has anti-apoptotic and pro-axogenic properties.

  14. Cyclin-dependent kinase 5 modulates STAT3 and androgen receptor activation through phosphorylation of Ser⁷²⁷ on STAT3 in prostate cancer cells.

    Science.gov (United States)

    Hsu, Fu-Ning; Chen, Mei-Chih; Lin, Kuan-Chia; Peng, Yu-Ting; Li, Pei-Chi; Lin, Eugene; Chiang, Ming-Ching; Hsieh, Jer-Tsong; Lin, Ho

    2013-10-15

    Cyclin-dependent kinase 5 (Cdk5) is known to regulate prostate cancer metastasis. Our previous results indicated that Cdk5 activates androgen receptor (AR) and supports prostate cancer growth. We also found that STAT3 is a target of Cdk5 in promoting thyroid cancer cell growth, whereas STAT3 may play a role as a regulator to AR activation under cytokine control. In this study, we investigated the regulation of Cdk5 and its activator p35 on STAT3/AR signaling in prostate cancer cells. Our results show that Cdk5 biochemically interacts with STAT3 and that this interaction depends on Cdk5 activation in prostate cancer cells. The phosphorylation of STAT3 at Ser⁷²⁷ (p-Ser⁷²⁷-STAT3) is regulated by Cdk5 in cells and xenograft tumors. The mutant of STAT3 S727A reduces its interaction with Cdk5. We further show that the nuclear distribution of p-Ser⁷²⁷-STAT3 and the expression of STAT3-regulated genes (junB, c-fos, c-myc, and survivin) are regulated by Cdk5 activation. STAT3 mutant does not further decrease cell proliferation upon Cdk5 inhibition, which implies that the role of STAT3 regulated by Cdk5 correlates to cell proliferation control. Interestingly, Cdk5 may regulate the interaction between STAT3 and AR through phosphorylation of Ser⁷²⁷-STAT3 and therefore upregulate AR protein stability and transactivation. Correspondingly, clinical evidence shows that the level of p-Ser⁷²⁷-STAT3 is significantly correlated with Gleason score and the levels of upstream regulators (Cdk5 and p35) as well as downstream protein (AR). In conclusion, this study demonstrates that Cdk5 regulates STAT3 activation through Ser⁷²⁷ phosphorylation and further promotes AR activation by protein-protein interaction in prostate cancer cells.

  15. Persistent STAT3 Activation in Colon Cancer Is Associated with Enhanced Cell Proliferation and Tumor Growth

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    Florian M. Corvinus

    2005-06-01

    Full Text Available Colorectal carcinoma (CRC is a major cause of morbidity and mortality in Western countries. It has so far been molecularly defined mainly by alterations of the Wnt pathway. We show here for the first time that aberrant activities of the signal transducer and activator of transcription STAT3 actively contribute to this malignancy and, thus, are a potential therapeutic target for CRC. Constitutive STAT3 activity was found to be abundant in dedifferentiated cancer cells and infiltrating lymphocytes of CRC samples, but not in non-neoplastic colon epithelium. Cell lines derived from malignant colorectal tumors lost persistent STAT3 activity in culture. However, implantation of colon carcinoma cells into nude mice resulted in restoration of STAT3 activity, suggesting a role of an extracellular stimulus within the tumor microenvironment as a trigger for STAT activation. STAT3 activity in CRC cells triggered through interleukin-6 or through a constitutively active STAT3 mutant promoted cancer cell multiplication, whereas STAT3 inhibition through a dominant-negative variant impaired IL-6-driven proliferation. Blockade of STAT3 activation in CRCderived xenograft tumors slowed down their development, arguing for a contribution of STAT3 to colorectal tumor growth.

  16. Early activation of STAT3 regulates reactive astrogliosis induced by diverse forms of neurotoxicity.

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    James P O'Callaghan

    Full Text Available Astrogliosis, a cellular response characterized by astrocytic hypertrophy and accumulation of GFAP, is a hallmark of all types of central nervous system (CNS injuries. Potential signaling mechanisms driving the conversion of astrocytes into "reactive" phenotypes differ with respect to the injury models employed and can be complicated by factors such as disruption of the blood-brain barrier (BBB. As denervation tools, neurotoxicants have the advantage of selective targeting of brain regions and cell types, often with sparing of the BBB. Previously, we found that neuroinflammation and activation of the JAK2-STAT3 pathway in astrocytes precedes up regulation of GFAP in the MPTP mouse model of dopaminergic neurotoxicity. Here we show that multiple mechanistically distinct mouse models of neurotoxicity (MPTP, AMP, METH, MDA, MDMA, KA, TMT engender the same neuroinflammatory and STAT3 activation responses in specific regions of the brain targeted by each neurotoxicant. The STAT3 effects seen for TMT in the mouse could be generalized to the rat, demonstrating cross-species validity for STAT3 activation. Pharmacological antagonists of the neurotoxic effects blocked neuroinflammatory responses, pSTAT3tyr705 and GFAP induction, indicating that damage to neuronal targets instigated astrogliosis. Selective deletion of STAT3 from astrocytes in STAT3 conditional knockout mice markedly attenuated MPTP-induced astrogliosis. Monitoring STAT3 translocation in GFAP-positive cells indicated that effects of MPTP, METH and KA on pSTAT3tyr705 were localized to astrocytes. These findings strongly implicate the STAT3 pathway in astrocytes as a broadly triggered signaling pathway for astrogliosis. We also observed, however, that the acute neuroinflammatory response to the known inflammogen, LPS, can activate STAT3 in CNS tissue without inducing classical signs of astrogliosis. Thus, acute phase neuroinflammatory responses and neurotoxicity-induced astrogliosis both

  17. STAT3 can be activated through paracrine signaling in breast epithelial cells

    International Nuclear Information System (INIS)

    Many cancers, including breast cancer, have been identified with increased levels of phosphorylated or the active form of Signal Transducers and Activators of Transcription 3 (STAT3) protein. However, whether the tumor microenvironment plays a role in this activation is still poorly understood. Conditioned media, which contains soluble factors from MDA-MB-231 and MDA-MB-468 breast cancer cells and breast cancer associated fibroblasts, was added to MCF-10A breast epithelial and MDA-MB-453 breast cancer cells. The stimulation of phosphorylated STAT3 (p-STAT3) levels by conditioned media was assayed by Western blot in the presence or absence of neutralized IL-6 antibody, or a JAK/STAT3 inhibitor, JSI-124. The stimulation of cell proliferation in MCF-10A cells by conditioned media in the presence or absence of JSI-124 was subjected to MTT analysis. IL-6, IL-10, and VEGF levels were determined by ELISA analysis. Our results demonstrated that conditioned media from cell lines with constitutively active STAT3 are sufficient to induce p-STAT3 levels in various recipients that do not possess elevated p-STAT3 levels. This signaling occurs through the JAK/STAT3 pathway, leading to STAT3 phosphorylation as early as 30 minutes and is persistent for at least 24 hours. ELISA analysis confirmed a correlation between elevated levels of IL-6 production and p-STAT3. Neutralization of the IL-6 ligand or gp130 was sufficient to block increased levels of p-STAT3 (Y705) in treated cells. Furthermore, soluble factors within the MDA-MB-231 conditioned media were also sufficient to stimulate an increase in IL-6 production from MCF-10A cells. These results demonstrate STAT3 phosphorylation in breast epithelial cells can be stimulated by paracrine signaling through soluble factors from both breast cancer cells and breast cancer associated fibroblasts with elevated STAT3 phosphorylation. The induction of STAT3 phosphorylation is through the IL-6/JAK pathway and appears to be associated with

  18. STAT3 can be activated through paracrine signaling in breast epithelial cells

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    Sasser A Kate

    2008-10-01

    Full Text Available Abstract Background Many cancers, including breast cancer, have been identified with increased levels of phosphorylated or the active form of Signal Transducers and Activators of Transcription 3 (STAT3 protein. However, whether the tumor microenvironment plays a role in this activation is still poorly understood. Methods Conditioned media, which contains soluble factors from MDA-MB-231 and MDA-MB-468 breast cancer cells and breast cancer associated fibroblasts, was added to MCF-10A breast epithelial and MDA-MB-453 breast cancer cells. The stimulation of phosphorylated STAT3 (p-STAT3 levels by conditioned media was assayed by Western blot in the presence or absence of neutralized IL-6 antibody, or a JAK/STAT3 inhibitor, JSI-124. The stimulation of cell proliferation in MCF-10A cells by conditioned media in the presence or absence of JSI-124 was subjected to MTT analysis. IL-6, IL-10, and VEGF levels were determined by ELISA analysis. Results Our results demonstrated that conditioned media from cell lines with constitutively active STAT3 are sufficient to induce p-STAT3 levels in various recipients that do not possess elevated p-STAT3 levels. This signaling occurs through the JAK/STAT3 pathway, leading to STAT3 phosphorylation as early as 30 minutes and is persistent for at least 24 hours. ELISA analysis confirmed a correlation between elevated levels of IL-6 production and p-STAT3. Neutralization of the IL-6 ligand or gp130 was sufficient to block increased levels of p-STAT3 (Y705 in treated cells. Furthermore, soluble factors within the MDA-MB-231 conditioned media were also sufficient to stimulate an increase in IL-6 production from MCF-10A cells. Conclusion These results demonstrate STAT3 phosphorylation in breast epithelial cells can be stimulated by paracrine signaling through soluble factors from both breast cancer cells and breast cancer associated fibroblasts with elevated STAT3 phosphorylation. The induction of STAT3 phosphorylation is

  19. APE1/Ref-1 regulates STAT3 transcriptional activity and APE1/Ref-1-STAT3 dual-targeting effectively inhibits pancreatic cancer cell survival.

    Science.gov (United States)

    Cardoso, Angelo A; Jiang, Yanlin; Luo, Meihua; Reed, April M; Shahda, Safi; He, Ying; Maitra, Anirban; Kelley, Mark R; Fishel, Melissa L

    2012-01-01

    Pancreatic cancer is a largely incurable disease, and increasing evidence supports strategies targeting multiple molecular mediators of critical functions of pancreatic ductal adenocarcinoma cells. Intracellular redox state modulates the activity of various signal transduction pathways and biological processes, including cell survival, drug resistance and responsiveness to microenvironmental factors. Recently, it has been shown that the transcription factor STAT3 is under redox control, but the mechanisms involved in its regulation are unknown. Here, we demonstrate for the first time that STAT3 DNA binding and transcriptional activity is directly regulated by the redox function of the APE1/Ref-1 endonuclease, using overexpression and redox-specific mutational strategies, and gene knockdown. Also, pharmacological blockade of APE1/Ref-1 by the redox-selective inhibitor E3330 abrogates STAT3 DNA binding. Since APE1/Ref-1 also exerts redox control on other cancer-associated transcription factors, we assessed the impact of dual-targeting of STAT3 signaling and APE1/Ref-1 redox on pancreatic cancer cell functions. We observed that disruption of APE1/Ref-1 redox activity synergizes with STAT3 blockade to potently inhibit the proliferation and viability of human PDAC cells. Mechanistically, we show that STAT3-APE1/Ref-1 dual targeting promotes marked tumor cell apoptosis, with engagement of caspase-3 signaling, which are significantly increased in comparison to the effects triggered by single target blockade. Also, we show that STAT3-APE1/Ref-1 dual blockade results in significant inhibition of tumor cell migration. Overall, this work demonstrates that the transcriptional activity of STAT3 is directly regulated by the redox function of APE1/Ref-1, and that concurrent blockade of STAT3 and APE1/Ref-1 redox synergize effectively inhibit critical PDAC cell functions.

  20. Constitutive STAT3-activation in Sezary syndrome: tyrphostin AG490 inhibits STAT3-activation, interleukin-2 receptor expression and growth of leukemic Sezary cells

    DEFF Research Database (Denmark)

    Eriksen, K W; Kaltoft, K; Mikkelsen, G;

    2001-01-01

    Interleukin-2 (IL-2) is a growth factor which upon binding to high-affinity receptors (IL-2Ralphabetagamma) triggers mitogenesis in T cells. IL-2Ralpha expression is restricted to T cells which have recently encountered antigen, and in healthy individuals the majority (>95%) of peripheral T cells...... constitutive STAT3 activation in SS tumor cells. Moreover, our findings suggest that STAT3 activation might play an important role in the constitutive IL-2Ralpha expression, survival, and growth of malignant SS cells....

  1. INHIBITION OF IL-6-INDUCED STAT3 ACTIVATION IN MYELOMA CELLS BY PROTEIN KINASE A

    Institute of Scientific and Technical Information of China (English)

    宋伦; 黎燕; 沈倍奋

    2001-01-01

    To investigate the regulation effect of protein kinase A on IL-6-induced STAT3 activation in myeloma cells. Methods: Two human myeloma cell lines-Sko-007 and U266 were pretreated with Forskolin, a protein kinase A antagonist, and then stimulated by IL-6. The activation state of STAT3 in these two cells were examined by electrophoretic mobility shift assay (EMSA). Results: Although PKA pathway itself doesn't participate in IL-6 signal transduction in Sko-007 and U266 cells, activation of protein kinase A can inhibit IL-6-induced STAT3 activation in these two cell lines. Conclusion: There exists an inhibitory effect of protein kinase A on STAT3 activation in human myeloma cells treated by IL-6.

  2. JAB1 regulates unphosphorylated STAT3 DNA-binding activity through protein–protein interaction in human colon cancer cells

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    Nishimoto, Arata, E-mail: anishimo@yamaguchi-u.ac.jp [Department of Surgery and Clinical Science, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi 755-8505 (Japan); Kugimiya, Naruji; Hosoyama, Toru; Enoki, Tadahiko [Department of Surgery and Clinical Science, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi 755-8505 (Japan); Li, Tao-Sheng [Department of Stem Cell Biology, Nagasaki University Graduate School of Biomedical Sciences, 1-12-4 Sakamoto, Nagasaki 852-8523 (Japan); Hamano, Kimikazu [Department of Surgery and Clinical Science, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi 755-8505 (Japan)

    2013-08-30

    Highlights: •JAB1 interacted with unphosphorylated STAT3 in the nucleus. •JAB1 knockdown tended to increase nuclear STAT3 expression. •JAB1 knockdown significantly decreased unphosphorylated STAT3 DNA-binding activity. •JAB1 knockdown significantly decreased MDR1, NANOG, and VEGF expressions. •Nuclear JAB1, but not nuclear STAT3, correlated with STAT3 DNA-binding activity. -- Abstract: Recent studies have revealed that unphosphorylated STAT3 forms a dimer, translocates to the nucleus, binds to the STAT3 binding site, and activates the transcription of STAT3 target genes, thereby playing an important role in oncogenesis in addition to phosphorylated STAT3. Among signaling steps of unphosphorylated STAT3, nuclear translocation and target DNA-binding are the critical steps for its activation. Therefore, elucidating the regulatory mechanism of these signaling steps of unphosphorylated STAT3 is a potential step in the discovery of a novel cancer drug. However, the mechanism of unphosphorylated STAT3 binding to the promoter of target genes remains unclear. In this study, we focused on Jun activation domain-binding protein 1 (JAB1) as a candidate protein that regulates unphosphorylated STAT3 DNA-binding activity. Initially, we observed that both unphosphorylated STAT3 and JAB1 existed in the nucleus of human colon cancer cell line COLO205 at the basal state (no cytokine stimulation). On the other hand, phosphorylated STAT3 did not exist in the nucleus of COLO205 cells at the basal state. Immunoprecipitation using nuclear extract of COLO205 cells revealed that JAB1 interacted with unphosphorylated STAT3. To investigate the effect of JAB1 on unphosphorylated STAT3 activity, RNAi studies were performed. Although JAB1 knockdown tended to increase nuclear STAT3 expression, it significantly decreased unphosphorylated STAT3 DNA-binding activity. Subsequently, JAB1 knockdown significantly decreased the expression levels of MDR1, NANOG, and VEGF, which are STAT3 target

  3. Convergent mutations and kinase fusions lead to oncogenic STAT3 activation in anaplastic large cell lymphoma.

    Science.gov (United States)

    Crescenzo, Ramona; Abate, Francesco; Lasorsa, Elena; Tabbo', Fabrizio; Gaudiano, Marcello; Chiesa, Nicoletta; Di Giacomo, Filomena; Spaccarotella, Elisa; Barbarossa, Luigi; Ercole, Elisabetta; Todaro, Maria; Boi, Michela; Acquaviva, Andrea; Ficarra, Elisa; Novero, Domenico; Rinaldi, Andrea; Tousseyn, Thomas; Rosenwald, Andreas; Kenner, Lukas; Cerroni, Lorenzo; Tzankov, Alexander; Ponzoni, Maurilio; Paulli, Marco; Weisenburger, Dennis; Chan, Wing C; Iqbal, Javeed; Piris, Miguel A; Zamo', Alberto; Ciardullo, Carmela; Rossi, Davide; Gaidano, Gianluca; Pileri, Stefano; Tiacci, Enrico; Falini, Brunangelo; Shultz, Leonard D; Mevellec, Laurence; Vialard, Jorge E; Piva, Roberto; Bertoni, Francesco; Rabadan, Raul; Inghirami, Giorgio

    2015-04-13

    A systematic characterization of the genetic alterations driving ALCLs has not been performed. By integrating massive sequencing strategies, we provide a comprehensive characterization of driver genetic alterations (somatic point mutations, copy number alterations, and gene fusions) in ALK(-) ALCLs. We identified activating mutations of JAK1 and/or STAT3 genes in ∼20% of 88 [corrected] ALK(-) ALCLs and demonstrated that 38% of systemic ALK(-) ALCLs displayed double lesions. Recurrent chimeras combining a transcription factor (NFkB2 or NCOR2) with a tyrosine kinase (ROS1 or TYK2) were also discovered in WT JAK1/STAT3 ALK(-) ALCL. All these aberrations lead to the constitutive activation of the JAK/STAT3 pathway, which was proved oncogenic. Consistently, JAK/STAT3 pathway inhibition impaired cell growth in vitro and in vivo. PMID:25873174

  4. Lung Adenocarcinomas and Lung Cancer Cell Lines Show Association of MMP-1 Expression With STAT3 Activation

    Directory of Open Access Journals (Sweden)

    Alexander Schütz

    2015-04-01

    Full Text Available Signal transducer and activator of transcription 3 (STAT3 is constitutively activated in the majority of lung cancer. This study aims at defining connections between STAT3 function and the malignant properties of non–small cell lung carcinoma (NSCLC cells. To address possible mechanisms by which STAT3 influences invasiveness, the expression of matrix metalloproteinase-1 (MMP-1 was analyzed and correlated with the STAT3 activity status. Studies on both surgical biopsies and on lung cancer cell lines revealed a coincidence of STAT3 activation and strong expression of MMP-1. MMP-1 and tyrosine-phosphorylated activated STAT3 were found co-localized in cancer tissues, most pronounced in tumor fronts, and in particular in adenocarcinomas. STAT3 activity was constitutive, although to different degrees, in the lung cancer cell lines investigated. Three cell lines (BEN, KNS62, and A549 were identified in which STAT3 activitation was inducible by Interleukin-6 (IL-6. In A549 cells, STAT3 activity enhanced the level of MMP-1 mRNA and stimulated transcription from the MMP-1 promoter in IL-6–stimulated A549 cells. STAT3 specificity of this effect was confirmed by STAT3 knockdown through RNA interference. Our results link aberrant activity of STAT3 in lung cancer cells to malignant tumor progression through up-regulation of expression of invasiveness-associated MMPs.

  5. IL-6 Inhibition Reduces STAT3 Activation and Enhances the Antitumor Effect of Carboplatin

    Science.gov (United States)

    Wang, Zhi-Yong; Zhang, Jun-Ai; Wu, Xian-Jin; Liang, Yan-Fang; Lu, Yuan-Bin; Gao, Yu-Chi; Dai, You-Chao; Yu, Shi-Yan; Jia, Yan; Fu, Xiao-Xia; Rao, Xiaoquan; Xu, Jun-Fa

    2016-01-01

    Recent studies suggest that tumor-associated macrophage-produced IL-6 is an important mediator within the tumor microenvironment that promotes tumor growth. The activation of IL-6/STAT3 axis has been associated with chemoresistance and poor prognosis of a variety of cancers including colorectal carcinoma and thus serves as a potential immunotherapeutic target for cancer treatment. However, it is not fully understood whether anticytokine therapy could reverse chemosensitivity and enhance the suppressive effect of chemotherapy on tumor growth. In this study, we aimed to investigate the effect of IL-6 inhibition therapy on the antitumor effect of carboplatin. Enhanced expression of IL-6 and activation of STAT3 were observed in human colorectal carcinoma samples compared to normal colorectal tissue, with higher levels of IL-6/STAT3 in low grade carcinomas. Treatment of carboplatin (CBP) dose-dependently increased IL-6 production and STAT3 activation in human colorectal LoVo cells. Blockade of IL-6 with neutralizing antibody enhanced chemosensitivity of LoVo cells to carboplatin as evidenced by increased cell apoptosis. IL-6 blockade abolished carboplatin-induced STAT3 activation. IL-6 blockade and carboplatin synergistically reduced cyclin D1 expression and enhanced caspase-3 activity in LoVo cells. Our results suggest that inhibition of IL-6 may enhance chemosensitivity of colon cancers with overactive STAT3 to platinum agents. PMID:27006530

  6. IL-6 Inhibition Reduces STAT3 Activation and Enhances the Antitumor Effect of Carboplatin

    Directory of Open Access Journals (Sweden)

    Zhi-Yong Wang

    2016-01-01

    Full Text Available Recent studies suggest that tumor-associated macrophage-produced IL-6 is an important mediator within the tumor microenvironment that promotes tumor growth. The activation of IL-6/STAT3 axis has been associated with chemoresistance and poor prognosis of a variety of cancers including colorectal carcinoma and thus serves as a potential immunotherapeutic target for cancer treatment. However, it is not fully understood whether anticytokine therapy could reverse chemosensitivity and enhance the suppressive effect of chemotherapy on tumor growth. In this study, we aimed to investigate the effect of IL-6 inhibition therapy on the antitumor effect of carboplatin. Enhanced expression of IL-6 and activation of STAT3 were observed in human colorectal carcinoma samples compared to normal colorectal tissue, with higher levels of IL-6/STAT3 in low grade carcinomas. Treatment of carboplatin (CBP dose-dependently increased IL-6 production and STAT3 activation in human colorectal LoVo cells. Blockade of IL-6 with neutralizing antibody enhanced chemosensitivity of LoVo cells to carboplatin as evidenced by increased cell apoptosis. IL-6 blockade abolished carboplatin-induced STAT3 activation. IL-6 blockade and carboplatin synergistically reduced cyclin D1 expression and enhanced caspase-3 activity in LoVo cells. Our results suggest that inhibition of IL-6 may enhance chemosensitivity of colon cancers with overactive STAT3 to platinum agents.

  7. Monocytes induce STAT3 activation in human mesenchymal stem cells to promote osteoblast formation.

    Directory of Open Access Journals (Sweden)

    Vicky Nicolaidou

    Full Text Available A major therapeutic challenge is how to replace bone once it is lost. Bone loss is a characteristic of chronic inflammatory and degenerative diseases such as rheumatoid arthritis and osteoporosis. Cells and cytokines of the immune system are known to regulate bone turnover by controlling the differentiation and activity of osteoclasts, the bone resorbing cells. However, less is known about the regulation of osteoblasts (OB, the bone forming cells. This study aimed to investigate whether immune cells also regulate OB differentiation. Using in vitro cell cultures of human bone marrow-derived mesenchymal stem cells (MSC, it was shown that monocytes/macrophages potently induced MSC differentiation into OBs. This was evident by increased alkaline phosphatase (ALP after 7 days and the formation of mineralised bone nodules at 21 days. This monocyte-induced osteogenic effect was mediated by cell contact with MSCs leading to the production of soluble factor(s by the monocytes. As a consequence of these interactions we observed a rapid activation of STAT3 in the MSCs. Gene profiling of STAT3 constitutively active (STAT3C infected MSCs using Illumina whole human genome arrays showed that Runx2 and ALP were up-regulated whilst DKK1 was down-regulated in response to STAT3 signalling. STAT3C also led to the up-regulation of the oncostatin M (OSM and LIF receptors. In the co-cultures, OSM that was produced by monocytes activated STAT3 in MSCs, and neutralising antibodies to OSM reduced ALP by 50%. These data indicate that OSM, in conjunction with other mediators, can drive MSC differentiation into OB. This study establishes a role for monocyte/macrophages as critical regulators of osteogenic differentiation via OSM production and the induction of STAT3 signalling in MSCs. Inducing the local activation of STAT3 in bone cells may be a valuable tool to increase bone formation in osteoporosis and arthritis, and in localised bone remodelling during fracture repair.

  8. Activation of intestinal epithelial Stat3 orchestrates tissue defense during gastrointestinal infection.

    Directory of Open Access Journals (Sweden)

    Nadine Wittkopf

    Full Text Available Gastrointestinal infections with EHEC and EPEC are responsible for outbreaks of diarrheal diseases and represent a global health problem. Innate first-line-defense mechanisms such as production of mucus and antimicrobial peptides by intestinal epithelial cells are of utmost importance for host control of gastrointestinal infections. For the first time, we directly demonstrate a critical role for Stat3 activation in intestinal epithelial cells upon infection of mice with Citrobacter rodentium - a murine pathogen that mimics human infections with attaching and effacing Escherichia coli. C. rodentium induced transcription of IL-6 and IL-22 in gut samples of mice and was associated with activation of the transcription factor Stat3 in intestinal epithelial cells. C. rodentium infection induced expression of several antimicrobial peptides such as RegIIIγ and Pla2g2a in the intestine which was critically dependent on Stat3 activation. Consequently, mice with specific deletion of Stat3 in intestinal epithelial cells showed increased susceptibility to C. rodentium infection as indicated by high bacterial load, severe gut inflammation, pronounced intestinal epithelial cell death and dissemination of bacteria to distant organs. Together, our data implicate an essential role for Stat3 activation in intestinal epithelial cells during C. rodentium infection. Stat3 concerts the host response to bacterial infection by controlling bacterial growth and suppression of apoptosis to maintain intestinal epithelial barrier function.

  9. Constitutive Activation of STAT-3 and Neoplasm Invasion and Metastasis%STAT-3持续活化与肿瘤侵袭、转移

    Institute of Scientific and Technical Information of China (English)

    邹黎黎; 韩莉; 柳长柏

    2012-01-01

    The disorder of JAK-STAT(janus tyrosine kinase-signal transducer and activator of transcription) is one of the leading causes for the occurrence of tumors. Recent studies showed that STAT-3, an important transcription factor of JAK-STAT signal transduction pathway, can promote the rapid induction of genes by directly transducing signals from the receptor into the nucleus, and to play a pivotal role in mediating the biological response for this ligands. However, STAT-3 appears to have a dark side as well. STAT-3 can sus-tainablely activate in the tumor cells, and serve as a new target for tumor therapy as a protooncogene. Thus, it is helpful to gain a better understanding of the role of STAT-3 in tumorigenesis with the overview of the relationship between the constitutive activation of STAT-3 and the neoplasm invasion, metastasis, and cancer stem cells.%JAK-STAT(janus tyrosine kinase-signal transducer and activator of transcription)细胞信号转导途径的紊乱,是肿瘤发生最重要的原因之一.近年来的研究发现,STAT-3作为JAK-STAT信号转导途径中一个重要的调节分子,能够通过将信号直接转导入细胞核而快速激活下游基因,从而保证相应配体顺利完成信号转导过程.然而,STAT-3也有其“黑暗”的一面,其往往在恶性肿瘤细胞中表现为持续活化,作为一种原癌基因,成为肿瘤治疗的新靶标.因而,对近年来有关STAT-3的持续活化与恶性肿瘤细胞的侵袭、转移过程及肿瘤干细胞的关系作一概述,有助于深入了解STAT-3在肿瘤发生发展机制中发挥的作用.

  10. Novel STAT3 phosphorylation inhibitors exhibit potent growth suppressive activity in pancreatic and breast cancer cells

    Science.gov (United States)

    Lin, Li; Hutzen, Brian; Zuo, Mingxin; Ball, Sarah; Deangelis, Stephanie; Foust, Elizabeth; Pandit, Bulbul; Ihnat, Michael A.; Shenoy, Satyendra S.; Kulp, Samuel; Li, Pui-Kai; Li, Chenglong; Fuchs, James; Lin, Jiayuh

    2010-01-01

    The constitutive activation of Signal Transducer and Activator of Transcription 3 (STAT3) is frequently detected in most types of human cancer where it plays important roles in survival, drug-resistance, angiogenesis, and other functions. Targeting constitutive STAT3 signaling is thus an attractive therapeutic approach for these cancers. We have recently developed novel small molecule STAT3 inhibitors known as FLLL31 and FLLL32, which are derived from curcumin (the primary bioactive compound of turmeric). These compounds are designed to bind selectively to Janus Kinase 2 (JAK2) and the STAT3 SH2 domain, which serves crucial roles in STAT3 dimerization and signal transduction. Here we show that FLLL31 and FLLL32 are effective inhibitors of STAT3 phosphorylation, DNA binding activity, and transactivation in vitro, leading to the impediment of multiple oncogenic processes and the induction of apoptosis in pancreatic and breast cancer cell lines. FLLL31 and FLLL32 also inhibit colony formation in soft agar, cell invasion, and exhibit synergy with the anti-cancer drug doxorubicin against breast cancer cells. In addition, we show that FLLL32 can inhibit the induction of STAT3 phosphorylation by Interferon-α (IFNα) and Interleukin-6 (IL-6) in breast cancer cells. We also demonstrate that administration of FLLL32 can inhibit tumor growth and vascularity in chicken embryo xenografts as well as substantially reduce tumor volumes in mouse xenografts. Our findings highlight the potential of these new compounds and their efficacy in targeting pancreatic and breast cancers that exhibit constitutive STAT3 signaling. PMID:20215512

  11. Cutting edge: TCR stimulation by antibody and bacterial superantigen induces Stat3 activation in human T cells

    DEFF Research Database (Denmark)

    Gerwien, J; Nielsen, M; Labuda, T;

    1999-01-01

    -specific human CD4+ T cell lines. In contrast, IL-2 induces a rapid and transient tyrosine and serine phosphorylation of Stat3. Compared with IL-2, CD3 ligation induces a delayed Stat3 binding to oligonucleotide probes from the ICAM-1 and IL-2R alpha promoter. CD3-mediated activation of Stat3 is almost...

  12. Two naturally occurring terpenes, dehydrocostuslactone and costunolide, decrease intracellular GSH content and inhibit STAT3 activation.

    Directory of Open Access Journals (Sweden)

    Elena Butturini

    Full Text Available The main purpose of the present study is to envisage the molecular mechanism of inhibitory action of dehydrocostuslactone (DCE and costunolide (CS, two naturally occurring sesquiterpene lactones, towards the activation of signal transducer and activator of transcription 3 (STAT3. We report that, in human THP-1 cell line, they inhibit IL-6-elicited tyrosine phosphorylation of STAT3 and its DNA binding activity with EC(50 of 10 µM with concomitant down-regulation of the phosphorylation of the tyrosine Janus kinases JAK1, JAK2 and Tyk2. Furthermore, these compounds that contain an α-β-unsaturated carbonyl moiety and function as potent Michael reaction acceptor, induce a rapid drop in intracellular glutathione (GSH concentration by direct interaction with it, thereby triggering S-glutathionylation of STAT3. Dehydrocostunolide (HCS, the reduced form of CS lacking only the α-β-unsaturated carbonyl group, fails to exert any inhibitory action. Finally, the glutathione ethylene ester (GEE, the cell permeable GSH form, reverts the inhibitory action of DCE and CS on STAT3 tyrosine phosphorylation. We conclude that these two sesquiterpene lactones are able to induce redox-dependent post-translational modification of cysteine residues of STAT3 protein in order to regulate its function.

  13. AG490 inhibits NFATc1 expression and STAT3 activation during RANKL induced osteoclastogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chang-hong; Zhao, Jin-xia; Sun, Lin; Yao, Zhong-qiang; Deng, Xiao-li; Liu, Rui; Liu, Xiang-yuan, E-mail: liu-xiangyuan@263.net

    2013-06-14

    Highlights: •AG490 inhibits RANKL-induced osteoclastogenesis in RAW264.7 cells. •AG490 affects cell proliferation and cell cycle distribution. •AG490 reduces NFATc1 expression during RANKL-induced osteoclastogenesis. •AG490 disrupts the activation of RANKL-mediated JAK2/STAT3 signaling pathway. •STAT3 depletion partly mimics the effect of AG490 on RANKL-induced osteoclastogenesis. -- Abstract: Commonly, JAK/STAT relays cytokine signals for cell activation and proliferation, and recent studies have shown that the elevated expression of JAK/STAT is associated with the immune rejection of allografts and the inflammatory processes of autoimmune disease. However, the role which JAK2/STAT3 signaling plays in the receptor activator of nuclear factor-κB ligand (RANKL)-mediated osteoclastogenesis is unknown. In this study, we investigated the effects of AG490, specific JAK2 inhibitor, on osteoclast differentiation in vitro. AG490 significantly inhibited osteoclastogenesis in murine osteoclast precursor cell line RAW264.7 induced by RANKL. AG490 suppressed cell proliferation and delayed the G1 to S cell cycle transition. Furthermore, AG490 also suppressed the expression of nuclear factor of activated T cells (NFAT) c1 but not c-Fos in RAW264.7. Subsequently, we investigated various intracellular signaling components associated with osteoclastogenesis. AG490 had no effects on RANKL-induced activation of Akt, ERK1/2. Interestingly, AG490 partly inhibited RANKL-induced phosphorylation of Ser{sup 727} in STAT3. Additionally, down-regulation of STAT3 using siRNA resulted in suppression of TRAP, RANK and NFATc1 expression. In conclusion, we demonstrated that AG490 inhibited RANKL-induced osteoclastogenesis by suppressing NFATc1 production and cell proliferation via the STAT3 pathway. These results suggest that inhibition of JAK2 may be useful for the treatment of bone diseases characterized by excessive osteoclastogenesis.

  14. AG490 inhibits NFATc1 expression and STAT3 activation during RANKL induced osteoclastogenesis

    International Nuclear Information System (INIS)

    Highlights: •AG490 inhibits RANKL-induced osteoclastogenesis in RAW264.7 cells. •AG490 affects cell proliferation and cell cycle distribution. •AG490 reduces NFATc1 expression during RANKL-induced osteoclastogenesis. •AG490 disrupts the activation of RANKL-mediated JAK2/STAT3 signaling pathway. •STAT3 depletion partly mimics the effect of AG490 on RANKL-induced osteoclastogenesis. -- Abstract: Commonly, JAK/STAT relays cytokine signals for cell activation and proliferation, and recent studies have shown that the elevated expression of JAK/STAT is associated with the immune rejection of allografts and the inflammatory processes of autoimmune disease. However, the role which JAK2/STAT3 signaling plays in the receptor activator of nuclear factor-κB ligand (RANKL)-mediated osteoclastogenesis is unknown. In this study, we investigated the effects of AG490, specific JAK2 inhibitor, on osteoclast differentiation in vitro. AG490 significantly inhibited osteoclastogenesis in murine osteoclast precursor cell line RAW264.7 induced by RANKL. AG490 suppressed cell proliferation and delayed the G1 to S cell cycle transition. Furthermore, AG490 also suppressed the expression of nuclear factor of activated T cells (NFAT) c1 but not c-Fos in RAW264.7. Subsequently, we investigated various intracellular signaling components associated with osteoclastogenesis. AG490 had no effects on RANKL-induced activation of Akt, ERK1/2. Interestingly, AG490 partly inhibited RANKL-induced phosphorylation of Ser727 in STAT3. Additionally, down-regulation of STAT3 using siRNA resulted in suppression of TRAP, RANK and NFATc1 expression. In conclusion, we demonstrated that AG490 inhibited RANKL-induced osteoclastogenesis by suppressing NFATc1 production and cell proliferation via the STAT3 pathway. These results suggest that inhibition of JAK2 may be useful for the treatment of bone diseases characterized by excessive osteoclastogenesis

  15. Jak2-Independent Activation of Stat3 by Intracellular Angiotensin II in Human Mesangial Cells

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    Rekha Singh

    2011-01-01

    Full Text Available Ang II is shown to mediate the stimulatory effect of high glucose on TGF-b1 and extracellular matrix proteins in glomerular mesangial cells. Also inhibition of Ang II formation in cell media (extracellular and lysates (intracellular blocks high-glucose effects on TGF-b1 and matrix more effectively compared to inhibition of extracellular Ang II alone. To investigate whether intracellular Ang II can stimulate TGF-b1 and matrix independent of extracellular Ang II, cultured human mesangial cells were transfected with Ang II to increase intracellular Ang II levels and its effects on TGF-b1 and matrix proteins were determined. Prior to transfection, cells were treated with candesartan to block extracellular Ang II-induced responses via cell membrane AT1 receptors. Transfection of cells with Ang II resulted in increased levels of intracellular Ang II which was accompanied by increased production of TGF-b1, collagen IV, fibronectin, and cell proliferation as well. On further examination, intracellular Ang II was found to activate Stat3 transcription factor including increased Stat3 protein expression, tyrosine 705 phosphorylation, and DNA-binding activity. Treatment with AG-490, an inhibitor of Jak2, did not block intracellular Ang II-induced Stat3 phosphorylation at tyrosine 705 residue indicating a Jak2-independent mechanism used by intracellular Ang II for Stat3 phosphorylation. In contrast, extracellular Ang II-induced tyrosine 705 phosphorylation of Stat3 was inhibited by AG-490 confirming the presence of a Jak2-dependent pathway. These findings suggest that intracellular Ang II increases TGF-b1 and matrix in human mesangial cells and also activates Stat3 transcription factor without involvement of the extracellular Ang II signaling pathway.

  16. STAT3 activation and infiltration of eosinophil granulocytes in mycosis fungoides

    DEFF Research Database (Denmark)

    Fredholm, Simon; Gjerdrum, Lise Mette R; Willerslev-Olsen, Andreas;

    2014-01-01

    Eosinophil granulocytes have been implicated in anticancer immunity but recent data indicate that eosinophils can also promote cancer. Herein, we studied eosinophils in skin lesions from 43 patients with mycosis fungoides (MF). The presence of eosinophils correlated with disease stage: 78......% of patients with advanced disease displayed eosinophil infiltration, whereas this was only seen in 11% of patients with patches (p...) in malignant T-cells also stained positively for eosinophils, whereas this was only observed in 28% of pY-STAT3-negative patients (peosinophilic activation and trafficking factors: High-mobility group BOX-1 protein (HMGB1) and interleukin 5 (IL5). STAT3 si...

  17. A novel activating role of SRC and STAT3 on HGF transcription in human breast cancer cells

    Directory of Open Access Journals (Sweden)

    Elliott Bruce E

    2007-10-01

    Full Text Available Abstract We have previously determined that the HGF promoter can be transactivated by a combination of activated Src and wild-type Stat3 in the mouse breast cell lines HC11 and SP1. To determine if this pathway is of relevance for the human disease, a series of human breast and other human cells lines were examined, and the status of key proteins in these cells determined. All of the human breast cell lines exhibited strong transactivation by a combination of activated Src and Stat3. This activation was dependent on a Stat3 recognition element present at nt-95. The exception was the ErbB2 over-expressing cell line SK-BR-3 where Stat3 alone could transactivate HGF though Src augmented this effect. Increased phosphorylation of Stat3 tyrosine 705 was also observed in this line. Analysis of three ovarian cell lines revealed that Src/Stat3 expression was not able to activate the HGF promoter in two of these lines (SKOV3 and IOSE-80PC. Src/Stat3 expression did activate HGF transcription in OVCAR3 cells, but this effect was not mediated by the Stat3 site at nt-95. Stat3 phosphorylation at tyrosine 705 was observed in IOSE-80PC cells, but was insufficient to allow for activation of the HGF promoter. Human kidney (HEK293 and cervical carcinoma (HeLa cells were also not Src/Stat3 permissive, despite high levels of Stat3 phospho-Y705. These results suggest that human breast cells are a uniquely permissive environment for HGF transactivation by Src/Stat3 which may allow for the inappropriate activation of HGF transcription during the early stages of breast transformation. This could lead to paracrine or autocrine activation of the Met receptor in breast carcinoma cells.

  18. Identification of a novel Stat3 recruitment and activation motif within the granulocyte colony-stimulating factor receptor.

    Science.gov (United States)

    Chakraborty, A; Dyer, K F; Cascio, M; Mietzner, T A; Tweardy, D J

    1999-01-01

    Stat3 is essential for early embryonic development and for myeloid differentiation induced by the cytokines granulocyte colony-stimulating factor (G-CSF) and interleukin-6 (IL-6). Two isoforms of Stat3 have been identified, (p92) and beta (p83), which have distinct transcriptional and biological functions. Activation of both Stat3 and Stat3beta requires the distal cytoplasmic domain of the G-CSFR, which contains four Tyr at positions 704, 729, 744, and 764. The studies reported here were undertaken to determine which, if any, of these tyrosine residues participated in Stat3/beta recruitment and activation. We showed that Stat3 and Stat3beta were affinity purified using phosphopeptides containing Y704 and Y744 but not by nonphosphorylated peptide analogues or by phosphopeptides containing Y729 and Y764. Complementary results were obtained in studies examining the ability of these peptides to destabilize and inhibit DNA binding of activated Stat3. Both Y704 and Y744 contributed to optimal activation of Stat3/beta in M1 murine myeloid leukemia cells containing wild-type and Y-to-F mutant G-CSFR constructs. Carboxy-terminal to Y704 at the +3 position is Gln; YXXQ represents a consensus Stat3 recruitment and activation motif. Y744 is followed at the +3 position by Cys (C); YXXC, represents a novel motif implicated in the recruitment and activation of Stat3. Modeling of the SH2 domain of Stat3 based on homologous SH2 domains of known structure revealed polar residues whose side chains contact the +3 position. This substitution may confer specificity for the Y704- and Y744-based ligands by allowing H-bond formation between the binding surface and the Gln or Cys found at the respective +3 position.

  19. JAK Kinase Inhibition Abrogates STAT3 Activation and Head and Neck Squamous Cell Carcinoma Tumor Growth

    Directory of Open Access Journals (Sweden)

    Malabika Sen

    2015-03-01

    Full Text Available Aberrant activation of the Janus kinase (JAK/signal transducer and activator of transcription (STAT 3 has been implicated in cell proliferation and survival of many cancers including head and neck squamous cell carcinoma (HNSCC. AZD1480, an orally active pharmacologic inhibitor of JAK1/JAK2, has been tested in several cancer models. In the present study, the in vitro and in vivo effects of AZD1480 were evaluated in HNSCC preclinical models to test the potential use of JAK kinase inhibition for HNSCC therapy. AZD1480 treatment decreased HNSCC proliferation in HNSCC cell lines with half maximal effective concentration (EC50 values ranging from 0.9 to 4 μM in conjunction with reduction of pSTAT3Tyr705 expression. In vivo antitumor efficacy of AZD1480 was demonstrated in patient-derived xenograft (PDX models derived from two independent HNSCC tumors. Oral administration of AZD1480 reduced tumor growth in conjunction with decreased pSTAT3Tyr705 expression that was observed in both PDX models. These findings suggest that the JAK1/2 inhibitors abrogate STAT3 signaling and may be effective in HNSCC treatment approaches.

  20. Folic acid mediates activation of the pro-oncogene STAT3 via the Folate Receptor alpha.

    Science.gov (United States)

    Hansen, Mariann F; Greibe, Eva; Skovbjerg, Signe; Rohde, Sarah; Kristensen, Anders C M; Jensen, Trine R; Stentoft, Charlotte; Kjær, Karina H; Kronborg, Camilla S; Martensen, Pia M

    2015-07-01

    The signal transducer and activator of transcription 3 (STAT3) is a well-described pro-oncogene found constitutively activated in several cancer types. Folates are B vitamins that, when taken up by cells through the Reduced Folate Carrier (RFC), are essential for normal cell growth and replication. Many cancer cells overexpress a glycophosphatidylinositol (GPI)-anchored Folate Receptor α (FRα). The function of FRα in cancer cells is still poorly described, and it has been suggested that transport of folate is not its primary function in these cells. We show here that folic acid and folinic acid can activate STAT3 through FRα in a Janus Kinase (JAK)-dependent manner, and we demonstrate that gp130 functions as a transducing receptor for this signalling. Moreover, folic acid can promote dose dependent cell proliferation in FRα-positive HeLa cells, but not in FRα-negative HEK293 cells. After folic acid treatment of HeLa cells, up-regulation of the STAT3 responsive genes Cyclin A2 and Vascular Endothelial Growth Factor (VEGF) were verified by qRT-PCR. The identification of this FRα-STAT3 signal transduction pathway activated by folic and folinic acid contributes to the understanding of the involvement of folic acid in preventing neural tube defects as well as in tumour growth. Previously, the role of folates in these diseases has been attributed to their roles as one-carbon unit donors following endocytosis into the cell. Our finding that folic acid can activate STAT3 via FRα adds complexity to the established roles of B9 vitamins in cancer and neural tube defects.

  1. Gain-of-function STAT1 mutations impair STAT3 activity in patients with chronic mucocutaneous candidiasis (CMC).

    Science.gov (United States)

    Zheng, Jie; van de Veerdonk, Frank L; Crossland, Katherine L; Smeekens, Sanne P; Chan, Chun M; Al Shehri, Tariq; Abinun, Mario; Gennery, Andrew R; Mann, Jelena; Lendrem, Dennis W; Netea, Mihai G; Rowan, Andrew D; Lilic, Desa

    2015-10-01

    Signal transducer and activator of transcription 3 (STAT3) triggered production of Th-17 cytokines mediates protective immunity against fungi. Mutations affecting the STAT3/interleukin 17 (IL-17) pathway cause selective susceptibility to fungal (Candida) infections, a hallmark of chronic mucocutaneous candidiasis (CMC). In patients with autosomal dominant CMC, we and others previously reported defective Th17 responses and underlying gain-of-function (GOF) STAT1 mutations, but how this affects STAT3 function leading to decreased IL-17 is unclear. We also assessed how GOF-STAT1 mutations affect STAT3 activation, DNA binding, gene expression, cytokine production, and epigenetic modifications. We excluded impaired STAT3 phosphorylation, nuclear translocation, and sequestration of STAT3 into STAT1/STAT3 heterodimers and confirm significantly reduced transcription of STAT3-inducible genes (RORC/IL-17/IL-22/IL-10/c-Fos/SOCS3/c-Myc) as likely underlying mechanism. STAT binding to the high affinity sis-inducible element was intact but binding to an endogenous STAT3 DNA target was impaired. Reduced STAT3-dependent gene transcription was reversed by inhibiting STAT1 activation with fludarabine or enhancing histone, but not STAT1 or STAT3 acetylation with histone deacetylase (HDAC) inhibitors trichostatin A or ITF2357. Silencing HDAC1, HDAC2, and HDAC3 indicated a role for HDAC1 and 2. Reduced STAT3-dependent gene transcription underlies low Th-17 responses in GOF-STAT1 CMC, which can be reversed by inhibiting acetylation, offering novel targets for future therapies.

  2. Drug-repositioning screening identified piperlongumine as a direct STAT3 inhibitor with potent activity against breast cancer.

    Science.gov (United States)

    Bharadwaj, U; Eckols, T K; Kolosov, M; Kasembeli, M M; Adam, A; Torres, D; Zhang, X; Dobrolecki, L E; Wei, W; Lewis, M T; Dave, B; Chang, J C; Landis, M D; Creighton, C J; Mancini, M A; Tweardy, D J

    2015-03-12

    Signal transducer and activator of transcription (STAT) 3 regulates many cardinal features of cancer including cancer cell growth, apoptosis resistance, DNA damage response, metastasis, immune escape, tumor angiogenesis, the Warburg effect and oncogene addiction and has been validated as a drug target for cancer therapy. Several strategies have been used to identify agents that target Stat3 in breast cancer but none has yet entered into clinical use. We used a high-throughput fluorescence microscopy search strategy to identify compounds in a drug-repositioning library (Prestwick library) that block ligand-induced nuclear translocation of Stat3 and identified piperlongumine (PL), a natural product isolated from the fruit of the pepper Piper longum. PL inhibited Stat3 nuclear translocation, inhibited ligand-induced and constitutive Stat3 phosphorylation, and modulated expression of multiple Stat3-regulated genes. Surface plasmon resonance assay revealed that PL directly inhibited binding of Stat3 to its phosphotyrosyl peptide ligand. Phosphoprotein antibody array analysis revealed that PL does not modulate kinases known to activate Stat3 such as Janus kinases, Src kinase family members or receptor tyrosine kinases. PL inhibited anchorage-independent and anchorage-dependent growth of multiple breast cancer cell lines having increased pStat3 or total Stat3, and induced apoptosis. PL also inhibited mammosphere formation by tumor cells from patient-derived xenografts. PL's antitumorigenic function was causally linked to its Stat3-inhibitory effect. PL was non-toxic in mice up to a dose of 30 mg/kg/day for 14 days and caused regression of breast cancer cell line xenografts in nude mice. Thus, PL represents a promising new agent for rapid entry into the clinic for use in treating breast cancer, as well as other cancers in which Stat3 has a role. PMID:24681959

  3. IL-6/STAT3 signaling pathway is activated in plasma cell mastitis.

    Science.gov (United States)

    Liu, Yang; Zhang, Jian; Zhou, Yu-Hui; Jiang, Yi-Na; Zhang, Wei; Tang, Xiao-Jiang; Ren, Yu; Han, Shui-Ping; Liu, Pei-Jun; Xu, Jing; He, Jian-Jun

    2015-01-01

    Plasma cell mastitis (PCM), a particular type of mastitis, mainly occurs in females at nonpregnant and nonlactating stages. The infiltration of abundant plasma cells and lymphocytes is the hallmark of the disease. The incidence rate of PCM increased gradually and its pathogenesis remained unclear. In this study, we investigated the expression of IL-6/STAT3 signaling pathway, which is vital not only for the differentiation of plasma cells but also for survival of plasma cells and T lymphocytes, in 30 PCM cases, 10 acute mastitis cases and 10 normal breast tissues by immunohistochemical analysis. IL-6 level was significantly higher in PCM patients than in acute mastitis patients or normal group. The positive rate of IL-6 and p-STAT3 staining in PCM samples was 93.3% (28/30) and 70% (21/30), respectively, and there was a significant positive association between IL-6 and p-STAT3 staining (r=0.408, P=0.025). In PCM group, the rate of nipple retraction was 40% (12/30). Significantly higher IL-6 expression was found in PCM patients with nipple retraction than in other PCM patients. However, no significant difference in IL-6 or p-STAT3 staining was detected between PCM patients experiencing recurrence and other PCM patients. In addition, Bcl-2 level was higher in PCM patients than in acute mastitis patients or normal group, but there was no difference in Bcl-2 immunostaining between PCM patients experiencing recurrence and other PCM patients. These indicate that IL-6/STAT3 signaling is activated in PCM and may play an important role in the pathogenesis of PCM.

  4. STAT3 pathway regulates lung-derived brain metastasis initiating cell capacity through miR-21 activation.

    Science.gov (United States)

    Singh, Mohini; Garg, Neha; Venugopal, Chitra; Hallett, Robin; Tokar, Tomas; McFarlane, Nicole; Mahendram, Sujeivan; Bakhshinyan, David; Manoranjan, Branavan; Vora, Parvez; Qazi, Maleeha; Arpin, Carolynn C; Page, Brent; Haftchenary, Sina; Rosa, David A; Lai, Ping-Shan; Gómez-Biagi, Rodolfo F; Ali, Ahmed M; Lewis, Andrew; Geletu, Mulu; Murty, Naresh K; Hassell, John A; Jurisica, Igor; Gunning, Patrick T; Singh, Sheila K

    2015-09-29

    Brain metastases (BM) represent the most common tumor to affect the adult central nervous system. Despite the increasing incidence of BM, likely due to consistently improving treatment of primary cancers, BM remain severely understudied. In this study, we utilized patient-derived stem cell lines from lung-to-brain metastases to examine the regulatory role of STAT3 in brain metastasis initiating cells (BMICs). Annotation of our previously described BMIC regulatory genes with protein-protein interaction network mapping identified STAT3 as a novel protein interactor. STAT3 knockdown showed a reduction in BMIC self-renewal and migration, and decreased tumor size in vivo. Screening of BMIC lines with a library of STAT3 inhibitors identified one inhibitor to significantly reduce tumor formation. Meta-analysis identified the oncomir microRNA-21 (miR-21) as a target of STAT3 activity. Inhibition of miR-21 displayed similar reductions in BMIC self-renewal and migration as STAT3 knockdown. Knockdown of STAT3 also reduced expression of known downstream targets of miR-21. Our studies have thus identified STAT3 and miR-21 as cooperative regulators of stemness, migration and tumor initiation in lung-derived BM. Therefore, STAT3 represents a potential therapeutic target in the treatment of lung-to-brain metastases. PMID:26314961

  5. Malignant T cells exhibit CD45 resistant Stat3 activation and proliferation in cutaneous

    DEFF Research Database (Denmark)

    Krejsgaard, Thorbjørn Frej; Helvad, Rikke; Ralfkiaer, Elisabeth;

    2010-01-01

    CD45 is a protein tyrosine phosphatase, which is well-known for regulating antigen receptor signalling in T and B cells via its effect on Src kinases. It has recently been shown that CD45 can also dephosphorylate Janus kinases (Jaks) and thereby regulate Signal transducer and activator of transcr......-mediated inhibition of proliferation. In conclusion, our data suggest that CD45 dysregulation might play a role in the aberrant proliferation and Jak3/Stat3 activation in CTCL....

  6. Constitutive STAT3 activation in intestinal T cells from patients with Crohn's disease

    DEFF Research Database (Denmark)

    Lovato, Paola; Brender, Christine; Agnholt, Jørgen;

    2003-01-01

    Via cytoplasmic signal transduction pathways, cytokines induce a variety of biological responses and modulate the outcome of inflammatory diseases and malignancies. Crohn's disease is a chronic inflammatory bowel disease of unknown etiology. Perturbation of the intestinal cytokine homeostasis...... is believed to play a pivotal role, but the pathogenesis of Crohn's disease is not fully understood. Here, we study intestinal T cells from Crohn's disease and healthy volunteers. We show that STAT3 and STAT4 are constitutively activated in Crohn's patients but not in healthy volunteers. The activation...... is specific, because other STAT proteins are not constitutively activated. Furthermore, the STAT3 regulated protein, SOCS3, is also constitutively expressed in Crohn's patients but not in healthy volunteers. Taken together, these data provide evidence of abnormal STAT/SOCS signaling in Crohn's disease...

  7. Gain-of-function STAT1 mutations impair STAT3 activity in patients with chronic mucocutaneous candidiasis (CMC)

    NARCIS (Netherlands)

    Zheng, J.; Veerdonk, F.L. van de; Crossland, K.L.; Smeekens, S.P.; Chan, C.M.; Shehri, T. Al; Abinun, M.; Gennery, A.R.; Mann, J.; Lendrem, D.W.; Netea, M.G.; Rowan, A.D.; Lilic, D.

    2015-01-01

    Signal transducer and activator of transcription 3 (STAT3) triggered production of Th-17 cytokines mediates protective immunity against fungi. Mutations affecting the STAT3/interleukin 17 (IL-17) pathway cause selective susceptibility to fungal (Candida) infections, a hallmark of chronic mucocutaneo

  8. Multilevel dysregulation of STAT3 activation in anaplastic lymphoma kinase-positive T/null-cell lymphoma

    DEFF Research Database (Denmark)

    Zhang, Qian; Raghunath, Puthryaveett N; Xue, Liquan;

    2002-01-01

    Accumulating evidence indicates that expression of anaplastic lymphoma kinase (ALK), typically due to t(2;5) translocation, defines a distinct type of T/null-cell lymphoma (TCL). The resulting nucleophosmin (NPM) /ALK chimeric kinase is constitutively active and oncogenic. Downstream effector...... molecules triggered by NPM/ALK remain, however, largely unidentified. Here we report that NPM/ALK induces continuous activation of STAT3. STAT3 displayed tyrosine phosphorylation and DNA binding in all (four of four) ALK+ TCL cell lines tested. The activation of STAT3 was selective because none of the other...... known STATs was consistently tyrosine phosphorylated in these cell lines. In addition, malignant cells in tissue sections from all (10 of 10) ALK+ TCL patients expressed tyrosine-phosphorylated STAT3. Transfection of BaF3 cells with NPM/ALK resulted in tyrosine phosphorylation of STAT3. Furthermore...

  9. Avicin D: a protein reactive plant isoprenoid dephosphorylates Stat 3 by regulating both kinase and phosphatase activities.

    Directory of Open Access Journals (Sweden)

    Valsala Haridas

    Full Text Available Avicins, a class of electrophilic triterpenoids with pro-apoptotic, anti-inflammatory and antioxidant properties, have been shown to induce redox-dependant post-translational modification of cysteine residues to regulate protein function. Based on (a the cross-talk that occurs between redox and phosphorylation processes, and (b the role of Stat3 in the process of apoptosis and carcinogenesis, we chose to study the effects of avicins on the processes of phosphorylation/dephosphorylation in Stat3. Avicins dephosphorylate Stat3 in a variety of human tumor cell lines, leading to a decrease in the transcriptional activity of Stat3. The expression of Stat3-regulated proteins such as c-myc, cyclin D1, Bcl2, survivin and VEGF were reduced in response to avicin treatment. Underlying avicin-induced dephosphorylation of Stat3 was dephosphorylation of JAKs, as well as activation of protein phosphatase-1. Downregulation of both Stat3 activity and expression of Stat 3-controlled pro-survival proteins, contributes to the induction of apoptosis in avicin treated tumor cells. Based on the role of Stat3 in inflammation and wounding, and the in vivo inhibition of VEGF by avicins in a mouse skin carcinogenesis model, it is likely that avicin-induced inhibition of Stat3 activity results in the suppression of the pro-inflammatory and pro-oxidant stromal environment of tumors. Activation of PP-1, which also acts as a cellular economizer, combined with the redox regulation by avicins, can aid in redirecting metabolism from growth promoting anabolic to energy sparing pathways.

  10. ERK1/2 contributes negative regulation to STAT3 activity in HSS-transfected HepG2 cells

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    Signal transducer and activator of transcription 3 (STAT3) is a recently characterized transcription factor which is essential to liver regeneration. We have previously reported that hepatic stimulator substance (HSS), a novel growthpromoting substance, phosphorylated the epidermal growth factor (EGF) receptors and activated downstream RasMAP kinase (extracellular signal-regulated kinases, ERK1/2) cascade. However, whether HSS signal is related to STAT3pathway remains unclear. The present study is aiming to explore the regulatory effect of activation of ERK1/2 evoked by HSS on STAT3 phosphorylation and STAT3 signaling. Human hepatoma cell line HepG2 was stably transfected with HSS cDNA and HSS expression was measured by Northern blot. The results showed that the transfection of HSS into HepG2 resulted in remarkable increase in cellular proliferation as compared with the non-transfected cells, and it was further proved that the cellular proliferation in the HSS-transfected cells was related to ERK1/2 activation. Treatment of the cells with 50 μM of PD98059, an ERK1/2 specific upstream inhibitor, resulted in ERK1/2 inactivation completely.Inhibition of ERK1/2 allowed the tyrosine of STAT3 to be phosphorylated in a dose-dependent manner to PD98059.Furthermore, transient transfection of STAT3 mutant (STAT3S727A) into HSS-bearing cells could remarkably reverse the inhibitory effect of ERK1/2 on STAT3 phosphorylation. Based upon these results, it is concluded that ERK1/2negatively modulates STAT3 phosphorylation and this function is dependent on residual serine-727 (S727) of STAT3.

  11. In vivo activation of STAT3 in cutaneous T-cell lymphoma. Evidence for an antiapoptotic function of STAT3

    DEFF Research Database (Denmark)

    Sommer, V H; Clemmensen, O J; Nielsen, O;

    2004-01-01

    A characteristic feature of neoplastic transformation is a perpetual activation of oncogenic proteins. Here, we studied signal transducers and activators of transcription (STAT) in patients with mycosis fungoides (MF)/cutaneous T-cell lymphoma (CTCL). Malignant lymphocytes in dermal infiltrates...

  12. Berberine suppresses tumorigenicity and growth of nasopharyngeal carcinoma cells by inhibiting STAT3 activation induced by tumor associated fibroblasts

    International Nuclear Information System (INIS)

    Cortidis rhizoma (Huanglian) and its major therapeutic component, berberine, have drawn extensive attention in recent years for their anti-cancer properties. Growth inhibitory effects of berberine on multiple types of human cancer cells have been reported. Berberine inhibits invasion, induces cell cycle arrest and apoptosis in human cancer cells. The anti-inflammatory property of berberine, involving inhibition of Signal Transducer and Activator of Transcription 3 (STAT3) activation, has also been documented. In this study, we have examined the effects of berberine on tumorigenicity and growth of nasopharyngeal carcinoma (NPC) cells and their relationship to STAT3 signaling using both in vivo and in vitro models. Berberine effectively inhibited the tumorigenicity and growth of an EBV-positive NPC cell line (C666-1) in athymic nude mice. Inhibition of tumorigenic growth of NPC cells in vivo was correlated with effective inhibition of STAT3 activation in NPC cells inside the tumor xenografts grown in nude mice. In vitro, berberine inhibited both constitutive and IL-6-induced STAT3 activation in NPC cells. Inhibition of STAT3 activation by berberine induced growth inhibition and apoptotic response in NPC cells. Tumor-associated fibroblasts were found to secret IL-6 and the conditioned medium harvested from the fibroblasts also induced STAT3 activation in NPC cells. Furthermore, STAT3 activation by conditioned medium of tumor-associated fibroblasts could be blocked by berberine or antibodies against IL-6 and IL-6R. Our observation that berberine effectively inhibited activation of STAT3 induced by tumor-associated fibroblasts suggests a role of berberine in modulating the effects of tumor stroma on the growth of NPC cells. The effective inhibition of STAT3 activation in NPC cells by berberine supports its potential use in the treatment of NPC

  13. STAT3 Activity and Function in Cancer: Modulation by STAT5 and miR-146b

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Sarah R.; Xiang, Michael; Frank, David A., E-mail: david_frank@dfci.harvard.edu [Department of Medical Oncology, Dana-Farber Cancer Institute, and Departments of Medicine, Brigham and Women' s Hospital and Harvard Medical School, 450 Brookline Avenue, Boston, MA 02215 (United States)

    2014-04-23

    The transcription factor STAT3 regulates genes that control critical cellular processes such as proliferation, survival, pluripotency, and motility. Thus, under physiological conditions, the transcriptional function of STAT3 is tightly regulated as one part of a complex signaling matrix. When these processes are subverted through mutation or epigenetic events, STAT3 becomes highly active and drives elevated expression of genes underlying these phenotypes, leading to malignant cellular behavior. However, even in the presence of activated STAT3, other cellular modulators can have a major impact on the biological properties of a cancer cell, which is reflected in the clinical behavior of a tumor. Recent evidence has suggested that two such key modulators are the activation status of other STAT family members, particularly STAT5, and the expression of STAT3-regulated genes that are part of negative feedback circuits, including microRNAs such as miR-146b. With attention to these newly emerging areas, we will gain greater insight into the consequence of STAT3 activation in the biology of human cancers. In addition, understanding these subtleties of STAT3 signaling in cancer pathogenesis will allow the development of more rational molecular approaches to cancer therapy.

  14. Brevilin A, a novel natural product, inhibits janus kinase activity and blocks STAT3 signaling in cancer cells.

    Directory of Open Access Journals (Sweden)

    Xing Chen

    Full Text Available Signal abnormalities in human cells usually cause unexpected consequences for individual health. We focus on these kinds of events involved in JAK-STAT signal pathways, especially the ones triggered by aberrant activated STAT3, an oncoprotein which participates in essential processes of cell survival, growth and proliferation in many types of tumors, as well as immune diseases. By establishing a STAT3 signal based high-throughput drug screening system in human lung cancer A549 cells, we have screened a library from natural products which contained purified compounds from medicinal herbs. One compound, named Brevilin A, exhibited both strong STAT3 signal inhibition and STAT3 signal dependent cell growth inhibition. Further investigations revealed that Brevilin A not only inhibits STAT3 signaling but also STAT1 signaling for cytokines induced phosphorylation of STAT3 and STAT1 as well as the expression of their target genes. In addition, we found Brevilin A could attenuate the JAKs activity by blocking the JAKs tyrosine kinase domain JH1. The levels of cytokine induced phosphorylation of STATs and other substrates were dramatically reduced by treatment of Brevilin A. The roles of Brevilin A targeting on JAKs activity indicate that Brevilin A may not only be used as a STAT3 inhibitor but also a compound blocking other JAK-STAT hyperactivation. Thus, these findings provided a strong impetus for the development of selective JAK-STAT inhibitors and therapeutic drugs in order to improve survival of patients with hyperactivated JAKs and STATs.

  15. Activation of the GP130-STAT3 axis and its potential implications in nonalcoholic fatty liver disease.

    Science.gov (United States)

    Min, Hae-Ki; Mirshahi, Faridoddin; Verdianelli, Aurora; Pacana, Tommy; Patel, Vaishali; Park, Chun-Geon; Choi, Aejin; Lee, Jeong-Hoon; Park, Chung-Berm; Ren, Shunlin; Sanyal, Arun J

    2015-05-01

    The status of the GP130-STAT3 signaling pathway in humans with nonalcoholic fatty liver disease (NAFLD) and its relevance to disease pathogenesis are unknown. The expression of the gp130-STAT3 axis and gp130 cytokine receptors were studied in subjects with varying phenotypes of NAFLD including nonalcoholic steatohepatitis (NASH) and compared with lean and weight-matched controls without NAFLD. Gp130 and its downstream signaling element (Tyk2 and STAT3) expression were inhibited in obese controls whereas they were increased in NAFLD. IL-6 levels were increased in NASH and correlated with gp130 expression (P < 0.01). Palmitate inhibited gp130-STAT3 expression and signaling. IL-6 and palmitate inhibited hepatic insulin signaling via STAT3-dependent and independent mechanisms, respectively. STAT3 overexpression reversed palmitate-induced lipotoxicity by increasing autophagy (ATG7) and decreasing endoplasmic reticulum stress. These data demonstrate that the STAT3 pathway is activated in NAFLD and can worsen insulin resistance while protecting against other lipotoxic mechanisms of disease pathogenesis. PMID:25747354

  16. Eudesmane-type sesquiterpenoids from Salvia plebeia inhibit IL-6-induced STAT3 activation.

    Science.gov (United States)

    Jang, Hyun-Jae; Oh, Hyun-Mee; Hwang, Joo Tae; Kim, Mi-Hwa; Lee, Soyoung; Jung, Kyungsook; Kim, Young-Ho; Lee, Seung Woong; Rho, Mun-Chual

    2016-10-01

    Seven eudesmane-type sesquiterpenoid lactones and the known plebeiolide C were isolated from an ethanol-soluble extract of the aerial parts of Salvia plebeia R. Br. Their structures were determined via NMR and MS, and their absolute configurations were elucidated using ECD, and X-ray crystallographic analysis, as well as the modified Mosher ester method. All isolates were evaluated for their inhibitory effects on IL6-induced STAT3 promoter activation in stably transfected Hep3B cells. Of these isolates, eudebeiolide D exhibited an inhibitory effect with the IC50 value of 1.1 μM. PMID:27506573

  17. Leptin differentially regulate STAT3 activation in ob/ob mouse adipose mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Zhou Zhou

    2012-12-01

    Full Text Available Abstract Background Leptin-deficient ob/ob mice exhibit adipocyte hypertrophy and hyperplasia as well as elevated adipose tissue and systemic inflammation. Multipotent stem cells isolated from adult adipose tissue can differentiate into adipocytes ex vivo and thereby contribute toward increased adipocyte cell numbers, obesity, and inflamm ation. Currently, information is lacking regarding regulation of adipose stem cell numbers as well as leptin-induced inflammation and its signaling pathway in ob/ob mice. Methods Using leptin deficient ob/ob mice, we investigated whether leptin injection into ob/ob mice increases adipose stem cell numbers and adipose tissue inflammatory marker MCP-1 mRNA and secretion levels. We also determined leptin mediated signaling pathways in the adipose stem cells. Results We report here that adipose stem cell number is significantly increased following leptin injection in ob/ob mice and with treatment of isolated stem cells with leptin in vitro. Leptin also up-regulated MCP-1 secretion in a dose- and time-dependent manner. We further showed that increased MCP-1 mRNA levels were due to increased phosphorylation of Signal Transducer and Activator of Transcription 3 (STAT3 Ser727 but not STAT3 Tyr705 phosphorylation, suggesting differential regulation of MCP-1 gene expression under basal and leptin-stimulated conditions in adipose stem cells. Conclusions Taken together, these studies demonstrate that leptin increases adipose stem cell number and differentially activates STAT3 protein resulting in up-regulation of MCP-1 gene expression. Further studies of mechanisms mediating adipose stem cell hyperplasia and leptin signaling in obesity are warranted and may help identify novel anti-obesity target strategies.

  18. Predominant Activation of JAK/STAT3 Pathway by Interleukin-6 Is Implicated in Hepatocarcinogenesis12

    Science.gov (United States)

    Jung, In Hye; Choi, Jeffrey Hyun-Kyu; Chung, Yong-Yoon; Lim, Ga-Lam; Park, Young-Nyun; Park, Seung Woo

    2015-01-01

    Chronic inflammation is an important process leading to tumorigenesis. Therefore, targeting and controlling inflammation can be a promising cancer therapy. Inflammation is often caused by a variety of inflammatory cytokine such as the interleukin (IL)-6, a pleiotrophic cytokine known to be involved in the tumorigenesis. In this study, an in vivo hepatic tumorigenesis model of zebrafish was generated to demonstrate a direct consequence of the human IL6 expression causing hepatocarcinogenesis. To do this, an elevated expression of the hIL6 gene was established to specifically target the zebrafish hepatocytes by transgenesis. Interestingly, the elevated hIL6 expression caused the chronic inflammation which results in a massive infiltration of inflammatory cells. This eventually resulted in the generation of various dysplastic lesions such as clear cell, small cell, and large cell changes, and also eosinophilic and basophilic foci of hepatocellular alteration. Hepatocellular carcinoma was then developed in the transgenic zebrafish. Molecular characterization revealed upregulation of the downstream components involved in the IL6-mediated signaling pathways, especially PI3K/Akt and JAK/STAT3 pathways. Further investigation indicated that PI3K was the most reactive to the infiltrated inflammatory cells and dysplasia with large cell change, whereas STAT3 was heavily activated in the region with dysplastic foci, suggesting that the JAK/STAT3 pathway was mainly implicated in the hepatic tumorigenesis in the current model. Our present study provides an in vivo evidence of the relationship between chronic inflammation and tumorigenesis and reinforces the pivotal role of IL6 in the inflammation-associated hepatocarcinogenesis. PMID:26297436

  19. DRUG-REPOSITIONING SCREENING IDENTIFIED PIPERLONGUMINE AS A DIRECT STAT3 INHIBITOR WITH POTENT ACTIVITY AGAINST BREAST CANCER

    OpenAIRE

    Bharadwaj, Uddalak; Eckols, T. Kris; Kolosov, Mikhail; Kasembeli, Moses M.; Adam, Abel; Torres, David; Zhang, Xiaomei; Lacey E Dobrolecki; Wei, Wei; Lewis, Michael T; Dave, Bhuvanesh; Chang, Jenny C.; Landis, Melissa D.; Creighton, Chad J.; Mancini, Michael A.

    2014-01-01

    Signal transducer and activator of transcription (STAT) 3 regulates many cardinal features of cancer including cancer cell growth, apoptosis resistance, DNA damage response, metastasis, immune escape, tumor angiogenesis, the Warburg effect, and oncogene addiction and has been validated as a drug target for cancer therapy. Several strategies have been employed to identify agents that target Stat3 in breast cancer but none has yet entered into clinical use. We used a high-throughput fluorescenc...

  20. Novel STAT3 phosphorylation inhibitors exhibit potent growth-suppressive activity in pancreatic and breast cancer cells.

    Science.gov (United States)

    Lin, Li; Hutzen, Brian; Zuo, Mingxin; Ball, Sarah; Deangelis, Stephanie; Foust, Elizabeth; Pandit, Bulbul; Ihnat, Michael A; Shenoy, Satyendra S; Kulp, Samuel; Li, Pui-Kai; Li, Chenglong; Fuchs, James; Lin, Jiayuh

    2010-03-15

    The constitutive activation of signal transducer and activator of transcription 3 (STAT3) is frequently detected in most types of human cancer where it plays important roles in survival, drug resistance, angiogenesis, and other functions. Targeting constitutive STAT3 signaling is thus an attractive therapeutic approach for these cancers. We have recently developed novel small-molecule STAT3 inhibitors, known as FLLL31 and FLLL32, which are derived from curcumin (the primary bioactive compound of turmeric). These compounds are designed to bind selectively to Janus kinase 2 and the STAT3 Src homology-2 domain, which serve crucial roles in STAT3 dimerization and signal transduction. Here we show that FLLL31 and FLLL32 are effective inhibitors of STAT3 phosphorylation, DNA-binding activity, and transactivation in vitro, leading to the impediment of multiple oncogenic processes and the induction of apoptosis in pancreatic and breast cancer cell lines. FLLL31 and FLLL32 also inhibit colony formation in soft agar and cell invasion and exhibit synergy with the anticancer drug doxorubicin against breast cancer cells. In addition, we show that FLLL32 can inhibit the induction of STAT3 phosphorylation by IFNalpha and interleukin-6 in breast cancer cells. We also show that administration of FLLL32 can inhibit tumor growth and vascularity in chicken embryo xenografts as well as substantially reduce tumor volumes in mouse xenografts. Our findings highlight the potential of these new compounds and their efficacy in targeting pancreatic and breast cancers that exhibit constitutive STAT3 signaling. PMID:20215512

  1. Immunohistochemical expression of the oncogenic molecules active Stat3 and survivin in benign and malignant salivary gland tumors

    Science.gov (United States)

    Nikitakis, Nikolaos G.; Scheper, Mark A.; Papanicolaou, Vasileios S.; Sklavounou, Alexandra; Sauk, John J.

    2009-01-01

    Objective Signal transducer and activator of transcription 3 (Stat3) and survivin have been shown to exert oncogenic effects in various human neoplasms. The purpose of this study was to evaluate the expression of the tyrosine phosphorylated (active) Stat3 and survivin in various benign and malignant salivary gland tumors (SGTs). Study design Eighty-six SGTs (65 malignant and 21 benign tumors of various histopathologic subtypes) were immunohistochemically stained with anti-survivin or anti-phosphorylated tyrosine-705 (p-tyr) Stat3 antibodies. Immunohistochemical reactivity was graded in a semi-quantitative manner; a combined score of immunohistochemical positivity (0–6) was calculated for each tumor by adding the individual scores for percentage of tumor cells (0–3) and intensity of staining (0–3). Results Survivin was immunohistochemically detected in all studied benign and malignant SGTs; p-tyr Stat3 was also detected in the majority (91%) of SGTs. The average combined scores for survivin and p-tyr Stat3 immunohistochemical expression in the studied malignant SGTs was 4.40 and 3.35, respectively; the corresponding combined scores for survivin and p-tyr Stat3 in the studied benign SGTs were 4.37 and 3.22, respectively. No statistically significant differences (p>0.05) in p-tyr Stat3 or survivin expression were detected between the benign and malignant groups, or among the various examined histopathological subtypes of SGTs. In contrast, normal salivary gland elements in the vicinity of the studied tumors revealed only weak and focal survivin or p-tyr Stat3 immunoreactivity, mainly localized to ductal and mucous cells. Conclusions Our data indicate an almost universal expression of activated Stat3 and survivin in benign and malignant SGTs. Considering the well-established proliferative and anti-apoptotic properties of these molecules and their functional interrelationship, selective targeting techniques against Stat3 and/or survivin may represent promising

  2. Novel CD47: SIRPα dependent mechanism for the activation of STAT3 in antigen-presenting cell.

    Directory of Open Access Journals (Sweden)

    Natan Toledano

    Full Text Available Cell surface CD47 interacts with its receptor, signal-regulatory-protein α (SIRPα that is expressed predominantly on macrophages, to inhibit phagocytosis of normal, healthy cells. This "don't eat me" signal is mediated through tyrosine phosphorylation of SIRPα at the cytoplasmic ITIM motifs and the recruitment of the phosphatase, SHP-1. We previously revealed a novel mechanism for the activation of the STAT3 pathway and the regulation of human APC maturation and function that is based on cell:cell interaction. In this study, we present evidence supporting the notion that CD47:SIRPα serves as a cell surface receptor: ligand pair involved in this contact-dependent STAT3 activation and regulation of APC maturation. We show that upon co-culturing APC with various primary and tumor cell lines STAT3 phosphorylation and IL-10 expression are induced, and such regulation could be suppressed by specific CD47 siRNAs and shRNAs. Significantly, >50% reduction in CD47 expression abolished the contact-dependent inhibition of T cell activation. Furthermore, co-immunoprecipitation experiments revealed a physical association between SIRPα and STAT3. Thus, we suggest that in addition to signaling through the ITIM-SHP-1 complex that transmit an anti-phagocytotic, CD47:SIRPα also triggers STAT3 signaling that is linked to an immature APC phenotype and peripheral tolerance under steady state and pathological conditions.

  3. Stat3 activation of NF-κB p100 processing involves CBP/p300-mediated acetylation

    OpenAIRE

    Nadiminty, Nagalakshmi; Lou, Wei; Lee, Soo Ok; Lin, Xin; Trump, Donald L.; Gao, Allen C.

    2006-01-01

    Activation of the noncanonical NF-κB signaling pathway involved in the proteolytic processing of NF-κB p100 to p52 is tightly regulated, and overproduction of p52 leads to lymphocyte hyperplasia and transformation. We have demonstrated that active but not latent Stat3, expressed in many types of human cancers involved in cell proliferation and survival, induces p100 processing to p52 by activation of IKKα and subsequent phosphorylation of p100. The Stat3-mediated p100 processing to p52 requir...

  4. Relationship of STAT3 activity with chemosensitivity to cisplatin in prostate cancer cell lines%前列腺癌细胞系中STAT3活性与顺铂敏感性之间的关系

    Institute of Scientific and Technical Information of China (English)

    韩慧; 李春燕; 刘希; 储黎; 许青

    2012-01-01

    目的 研究前列腺癌细胞系中STAT3活性与顺铂敏感性之间的关系.方法 通过免疫细胞化学和蛋白质印迹法(Western blotting)检测3种常见前列腺癌细胞系LNCaP、PC3、DU145基础STAT3的活性;选取激素非依赖性细胞系PC3、DU145,分别加入2 ng/ml、20 ng/ml、200 ng/ml、2μg/ml、20 μg/ml顺铂检测细胞增殖抑制情况,蛋白质印迹法检测低浓度顺铂作用DU145后STAT3的活性变化.结果 激素非依赖性前列腺癌细胞系PC3、DU145中STAT3的活性较激素依赖性细胞系LNCaP中的高,且STAT3活性较低的PC3细胞较DU145细胞对顺铂更敏感,低浓度顺铂长时间作用DU145后可引起STAT3活性上调.结论 STAT3可能参与调节前列腺癌细胞对顺铂的敏感性.%Objective To investigate the relationship between STAT3 activity and sensitivity to cisplatin in prostate cancer cell lines. Methods STAT3 activity was examined by immunocytochemistry and Western blotting analysis in three prostate cancer cell lines: LNCaP, PC3 and DU145. Androgen-independent cell lines PC3 and DU145 were selected to examine the inhibitory effect of various concentrations of cisplatin (2 ng/ml, 20 ng/ml, 200 ng/ml, 2 pg/ml and 20 fxg/ml). STAT3 activity of DU145 cell line was re-examined by Western blotting analysis after treatment with low concentration of cisplatin. Results The STAT3 activity of androgen-independent cell lines PC3 and DU145 was higher than that of androgen-dependent cell line LNCaP. The sensitivity of DU145 cells to cisplatin was lower than that of PC3 cells with lower STAT3 activity. Treatment with low concentration of cisplatin for a long period caused STAT3 activation in DU145. Conclusion Our results suggest that STAT3 may play a role in regulating the sensitivity of prostate cancer cells to cisplatin.

  5. STAT3 activation is associated with cerebrospinal fluid interleukin-10 (IL-10) in primary central nervous system diffuse large B cell lymphoma.

    Science.gov (United States)

    Mizowaki, Takashi; Sasayama, Takashi; Tanaka, Kazuhiro; Mizukawa, Katsu; Takata, Kumi; Nakamizo, Satoshi; Tanaka, Hirotomo; Nagashima, Hiroaki; Nishihara, Masamitsu; Hirose, Takanori; Itoh, Tomoo; Kohmura, Eiji

    2015-09-01

    Signal transducers and activators of transcription 3 (STAT3) are activated by various cytokines and oncogenes; however, the activity and pathogenesis of STAT3 in diffuse large B cell lymphoma of the central nervous system have not been thoroughly elucidated. We investigated the phosphorylation levels of STAT3 in 40 specimens of primary central nervous system diffuse large B-cell lymphoma (PCNS DLBCL) and analyzed the association between phsopho-STAT3 (pSTAT3) expression and cerebrospinal fluid (CSF) concentration of interleukin-10 (IL-10) or IL-6. Immunohistochemistry and Western blot analysis revealed that most of the specimens in PCNS DLBCL expressed pSTST3 protein, and a strong phosphorylation levels of STAT3 was statistically associated with high CSF IL-10 levels, but not with CSF IL-6 levels. Next, we demonstrated that recombinant IL-10 and CSF containing IL-10 induced the phosphorylation of STAT3 in PCNS DLBCL cells. Furthermore, molecular subtype classified by Hans' algorithm was correlated with pSTAT3 expression levels and CSF IL-10 levels. These results suggest that the STAT3 activity is correlated with CSF IL-10 level, which is a useful marker for STAT3 activity in PCNS DLBCLs.

  6. Active Stat3 is required for survival of human squamous cell carcinoma cells in serum-free conditions

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    DiGiovanni John

    2006-04-01

    Full Text Available Abstract Background Squamous cell carcinoma (SCC of the skin is the most aggressive form of non-melanoma skin cancer (NMSC, and is the single most commonly diagnosed cancer in the U.S., with over one million new cases reported each year. Recent studies have revealed an oncogenic role of activated signal transducer and activator of transcription 3 (Stat3 in many human tumors, especially in those of epithelial origin, including skin SCC. Stat3 is a mediator of numerous growth factor and cytokine signaling pathways, all of which activate it through phosphorylation of tyrosine 705. Results To further address the role of Stat3 in skin SCC tumorigenesis, we have analyzed a panel of human skin-derived cell lines ranging from normal human epidermal keratinocytes (NHEK, to non-tumorigenic transformed skin cells (HaCaT, to highly tumorigenic cells (SRB1-m7 and SRB12-p9 and observed a positive correlation between Stat3 phosphorylation and SCC malignancy. We next determined the role of Stat3 activity in cell proliferation and viability under serum-free culture conditions. This was accomplished by suppressing Stat3 activity in the SRB12-p9 cells through stable expression of a dominant negative acting form of Stat3β, which contains a tyrosine 705 to phenylalanine mutation (S3DN. The S3DN cells behaved similar to parental SRB12-p9 cells when cultured in optimal growth conditions, in the presence of 10% fetal calf serum. However, unlike the SRB12-p9 cells, S3DN cells underwent apoptotic cell death when cultured in serum-free medium (SFM. This was evidenced by multiple criteria, including accumulation of sub-G1 particles, induced PARP cleavage, and acquisition of the characteristic morphological changes associated with apoptosis. Conclusion This study provides direct evidence for a role for Stat3 in maintaining cell survival in the conditions of exogenous growth factor deprivation produced by culture in SFM. We also propose that delivery of the S3DN gene or

  7. Activating mutations of STAT5B and STAT3 in lymphomas derived from ??-T or NK cells.

    OpenAIRE

    Lack, Nathan A.; Şen, Emel; Kucuk, Can; Jiang, Bei; Hu, Xiaozhou; Zhang, Wenyan; Chan, John K. C.; Xiao, Wenming; Alkan, Can; Williams, John C.; Avery, Kendra N.; Kavak, Pinar; Scuto, Anna; Gaulard, Philippe; Staudt, Lou; Iqbal, Javeed; Zhang, Weiwei; Cornish, Adam; Gong, Qiang; Yang, Qunpei; Sun, Hong; d'Amore, Francesco; Leppa, Sirpa; Liu, Weiping; Fu, Kai; de Leval, Laurence; McKeithan, Timothy; Chan, Wing C.

    2015-01-01

    Lymphomas arising from NK or gamma delta-T cells are very aggressive diseases and little is known regarding their pathogenesis. Here we report frequent activating mutations of STAT3 and STAT5B in NK/T-cell lymphomas (n - 51), gamma delta-T-cell lymphomas (n - 43) and their cell lines (n = 9) through next generation and/or Sanger sequencing. STAT5B N642H is particularly frequent in all forms of gamma delta-T-cell lymphomas. STAT3 and STAT5B mutations are associated with increased phosphorylate...

  8. SC-2001 Overcomes STAT3-mediated Sorafenib Resistance through RFX-1/SHP-1 Activation in Hepatocellular Carcinoma

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    Jung-Chen Su

    2014-07-01

    Full Text Available Hepatocellular carcinoma is the fifth most common solid cancer worldwide. Sorafenib, a small multikinase inhibitor, is the only approved therapy for advanced HCC. The clinical benefit of sorafenib is offset by the acquisition of sorafenib resistance. Understanding of the molecular mechanism of STAT3 overexpression in sorafenib resistance is critical if the clinical benefits of this drug are to be improved. In this study, we explored our hypothesis that loss of RFX-1/SHP-1 and further increase of p-STAT3 as a result of sorafenib treatment induces sorafenib resistance as a cytoprotective response effect, thereby, limiting sorafenib sensitivity and efficiency. We found that knockdown of RFX-1 protected HCC cells against sorafenib-induced cell apoptosis and SHP-1 activity was required for the process. SC-2001, a molecule with similar structure to obatoclax, synergistically suppressed tumor growth when used in combination with sorafenib in vitro and overcame sorafenib resistance through up-regulating RFX-1 and SHP-1 resulting in tumor suppression and mediation of dephosphorylation of STAT3. In addition, sustained sorafenib treatment in HCC led to increased p-STAT3 which was a key mediator of sorafenib sensitivity. The combination of SC-2001 and sorafenib strongly inhibited tumor growth in both wild-type and sorafenib-resistant HCC cell bearing xenograft models. These results demonstrate that inactivation of RFX/SHP-1 induced by sustained sorafenib treatment confers sorafenib resistance to HCC through p-STAT3 up-regulation. These effects can be overcome by SC-2001 through RFX-1/SHP-1 dependent p-STAT3 suppression. In conclusion, the use of SC-2001 in combination with sorafenib may constitute a new strategy for HCC therapy.

  9. STAT3 activation in skeletal muscle links muscle wasting and the acute phase response in cancer cachexia.

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    Andrea Bonetto

    Full Text Available BACKGROUND: Cachexia, or weight loss despite adequate nutrition, significantly impairs quality of life and response to therapy in cancer patients. In cancer patients, skeletal muscle wasting, weight loss and mortality are all positively associated with increased serum cytokines, particularly Interleukin-6 (IL-6, and the presence of the acute phase response. Acute phase proteins, including fibrinogen and serum amyloid A (SAA are synthesized by hepatocytes in response to IL-6 as part of the innate immune response. To gain insight into the relationships among these observations, we studied mice with moderate and severe Colon-26 (C26-carcinoma cachexia. METHODOLOGY/PRINCIPAL FINDINGS: Moderate and severe C26 cachexia was associated with high serum IL-6 and IL-6 family cytokines and highly similar patterns of skeletal muscle gene expression. The top canonical pathways up-regulated in both were the complement/coagulation cascade, proteasome, MAPK signaling, and the IL-6 and STAT3 pathways. Cachexia was associated with increased muscle pY705-STAT3 and increased STAT3 localization in myonuclei. STAT3 target genes, including SOCS3 mRNA and acute phase response proteins, were highly induced in cachectic muscle. IL-6 treatment and STAT3 activation both also induced fibrinogen in cultured C2C12 myotubes. Quantitation of muscle versus liver fibrinogen and SAA protein levels indicates that muscle contributes a large fraction of serum acute phase proteins in cancer. CONCLUSIONS/SIGNIFICANCE: These results suggest that the STAT3 transcriptome is a major mechanism for wasting in cancer. Through IL-6/STAT3 activation, skeletal muscle is induced to synthesize acute phase proteins, thus establishing a molecular link between the observations of high IL-6, increased acute phase response proteins and muscle wasting in cancer. These results suggest a mechanism by which STAT3 might causally influence muscle wasting by altering the profile of genes expressed and

  10. Plumbagin, Vitamin K3 Analogue, Suppresses STAT3 Activation Pathway through Induction of Protein Tyrosine Phosphatase, SHP-1: Potential Role in Chemosensitization

    OpenAIRE

    Sandur, Santosh K.; Pandey, Manoj K.; Sung, Bokyung; Aggarwal, Bharat B.

    2010-01-01

    The activation of STAT3 has been linked with carcinogenesis through survival, proliferation, and angiogenesis of tumor cells. Agents that can suppress STAT3 activation have potential not only for prevention but also for treatment of cancer. In the present report, we investigated whether plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone), an analogue of Vitamin K and isolated from chitrak (Plumbago zeylanica), an Ayurvedic medicinal plant, can modulate the STAT3 pathway. We found that plumbagin...

  11. Proinflammatory Cytokines Induce Endocrine Differentiation in Pancreatic Ductal Cells via STAT3-Dependent NGN3 Activation

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    Ivan Achel Valdez

    2016-04-01

    Full Text Available A major goal of diabetes research is to develop strategies that replenish pancreatic insulin-producing beta cells. One emerging strategy is to harness pancreatic plasticity—the ability of pancreatic cells to undergo cellular interconversions—a phenomenon implicated in physiological stress and pancreatic injury. Here, we investigate the effects of inflammatory cytokine stress on the differentiation potential of ductal cells in a human cell line, in mouse ductal cells by pancreatic intraductal injection, and during the progression of autoimmune diabetes in the non-obese diabetic (NOD mouse model. We find that inflammatory cytokine insults stimulate epithelial-to-mesenchymal transition (EMT as well as the endocrine program in human pancreatic ductal cells via STAT3-dependent NGN3 activation. Furthermore, we show that inflammatory cytokines activate ductal-to-endocrine cell reprogramming in vivo independent of hyperglycemic stress. Together, our findings provide evidence that inflammatory cytokines direct ductal-to-endocrine cell differentiation, with implications for beta cell regeneration.

  12. ZIP4 Regulates Pancreatic Cancer Cell Growth by Activating IL-6/STAT3 Pathway via Zinc Finger Transcription Factor CREB

    Science.gov (United States)

    Zhang, Yuqing; Bharadwaj, Uddalak; Logsdon, Craig D.; Chen, Changyi; Yao, Qizhi; Li, Min

    2010-01-01

    Purpose Recent studies indicate a strong correlation of zinc transporter ZIP4 and pancreatic cancer progression; however, the underlying mechanisms are unclear. We have recently found that ZIP4 is overexpressed in pancreatic cancer. In this study, we investigated the signaling pathway through which ZIP4 regulates pancreatic cancer growth. Experimental Design The expression of cyclin D1, IL-6, and STAT3 in pancreatic cancer xenografts and cells were examined by real time PCR, Bio-Plex cytokine assay, and Western blot, respectively. The activity of CREB is examined by a promoter activity assay. Results Cyclin D1 was significantly increased in the ZIP4 overexpressing MIA PaCa-2 cells (MIA-ZIP4)-injected orthotopic xenografts and was downregulated in the ZIP4 silenced ASPC-1 (ASPC-shZIP4) group. The phosphorylation of signal transducer and activator of transcription 3 (STAT3), an upstream activator of cyclin D1, was increased in MIA-ZIP4 cells, and decreased in ASPC-shZIP4 cells. IL-6, a known upstream activator for STAT3, was also found to be significantly increased in the MIA-ZIP4 cells and xenografts, and decreased in the ASPC-shZIP4 group. Overexpression of ZIP4 led to a 75% increase of IL-6 promoter activity, and caused increased phosphorylation of cAMP response element binding protein (CREB). Conclusions Our study suggest that ZIP4 overexpression causes increased IL-6 transcription via CREB, which in turn activates STAT3, and leads to increased cyclin D1 expression, resulting in increased cell proliferation and tumor progression in pancreatic cancer. These results elucidated a novel pathway in ZIP4-mediated pancreatic cancer growth, and suggest new therapeutic targets including ZIP4, IL-6, and STAT3 in pancreatic cancer treatment. PMID:20160059

  13. Highly pathogenic avian influenza H5N1 virus delays apoptotic responses via activation of STAT3.

    Science.gov (United States)

    Hui, Kenrie P Y; Li, Hung Sing; Cheung, Man Chun; Chan, Renee W Y; Yuen, Kit M; Mok, Chris K P; Nicholls, John M; Peiris, J S Malik; Chan, Michael C W

    2016-01-01

    Highly pathogenic avian influenza (HPAI) H5N1 virus continues to pose pandemic threat, but there is a lack of understanding of its pathogenesis. We compared the apoptotic responses triggered by HPAI H5N1 and low pathogenic H1N1 viruses using physiologically relevant respiratory epithelial cells. We demonstrated that H5N1 viruses delayed apoptosis in primary human bronchial and alveolar epithelial cells (AECs) compared to H1N1 virus. Both caspase-8 and -9 were activated by H5N1 and H1N1 viruses in AECs, while H5N1 differentially up-regulated TRAIL. H5N1-induced apoptosis was reduced by TRAIL receptor silencing. More importantly, STAT3 knock-down increased apoptosis by H5N1 infection suggesting that H5N1 virus delays apoptosis through activation of STAT3. Taken together, we demonstrate that STAT3 is involved in H5N1-delayed apoptosis compared to H1N1. Since delay in apoptosis prolongs the duration of virus replication and production of pro-inflammatory cytokines and TRAIL from H5N1-infected cells, which contribute to orchestrate cytokine storm and tissue damage, our results suggest that STAT3 may play a previously unsuspected role in H5N1 pathogenesis. PMID:27344974

  14. Highly pathogenic avian influenza H5N1 virus delays apoptotic responses via activation of STAT3

    Science.gov (United States)

    Hui, Kenrie P. Y.; Li, Hung Sing; Cheung, Man Chun; Chan, Renee W. Y.; Yuen, Kit M.; Mok, Chris K. P.; Nicholls, John M.; Peiris, J. S. Malik; Chan, Michael C. W.

    2016-01-01

    Highly pathogenic avian influenza (HPAI) H5N1 virus continues to pose pandemic threat, but there is a lack of understanding of its pathogenesis. We compared the apoptotic responses triggered by HPAI H5N1 and low pathogenic H1N1 viruses using physiologically relevant respiratory epithelial cells. We demonstrated that H5N1 viruses delayed apoptosis in primary human bronchial and alveolar epithelial cells (AECs) compared to H1N1 virus. Both caspase-8 and -9 were activated by H5N1 and H1N1 viruses in AECs, while H5N1 differentially up-regulated TRAIL. H5N1-induced apoptosis was reduced by TRAIL receptor silencing. More importantly, STAT3 knock-down increased apoptosis by H5N1 infection suggesting that H5N1 virus delays apoptosis through activation of STAT3. Taken together, we demonstrate that STAT3 is involved in H5N1-delayed apoptosis compared to H1N1. Since delay in apoptosis prolongs the duration of virus replication and production of pro-inflammatory cytokines and TRAIL from H5N1-infected cells, which contribute to orchestrate cytokine storm and tissue damage, our results suggest that STAT3 may play a previously unsuspected role in H5N1 pathogenesis. PMID:27344974

  15. STAT3 and STAT6 Signaling Pathways Synergize to Promote Cathepsin Secretion from Macrophages via IRE1α Activation.

    Science.gov (United States)

    Yan, Dongyao; Wang, Hao-Wei; Bowman, Robert L; Joyce, Johanna A

    2016-09-13

    Tumor-associated macrophages play critical roles during tumor progression by promoting angiogenesis, cancer cell proliferation, invasion, and metastasis. Cysteine cathepsin proteases, produced by macrophages and cancer cells, modulate these processes, but it remains unclear how these typically lysosomal enzymes are regulated and secreted within the tumor microenvironment. Here, we identify a STAT3 and STAT6 synergy that potently upregulates cathepsin secretion by macrophages via engagement of an unfolded protein response (UPR) pathway. Whole-genome expression analyses revealed that the TH2 cytokine interleukin (IL)-4 synergizes with IL-6 or IL-10 to activate UPR via STAT6 and STAT3. Pharmacological inhibition of the UPR sensor IRE1α blocks cathepsin secretion and blunts macrophage-mediated cancer cell invasion. Similarly, genetic deletion of STAT3 and STAT6 signaling components impairs tumor development and invasion in vivo. Together, these findings demonstrate that cytokine-activated STAT3 and STAT6 cooperate in macrophages to promote a secretory phenotype that enhances tumor progression in a cathepsin-dependent manner. PMID:27626662

  16. Interleukin-6 induces S100A9 expression in colonic epithelial cells through STAT3 activation in experimental ulcerative colitis.

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    Min Jeoung Lee

    Full Text Available BACKGROUND: Intestinal epithelium is essential for maintaining normal intestinal homeostasis; its breakdown leads to chronic inflammatory pathologies, such as inflammatory bowel diseases (IBDs. Although high concentrations of S100A9 protein and interleukin-6 (IL-6 are found in patients with IBD, the expression mechanism of S100A9 in colonic epithelial cells (CECs remains elusive. We investigated the role of IL-6 in S100A9 expression in CECs using a colitis model. METHODS: IL-6 and S100A9 expression, signal transducer and activator of transcription 3 (STAT3 phosphorylation, and infiltration of immune cells were analyzed in mice with dextran sulfate sodium (DSS-induced colitis. The effects of soluble gp130-Fc protein (sgp130Fc and S100A9 small interfering (si RNA (si-S100A9 on DSS-induced colitis were evaluated. The molecular mechanism of S100A9 expression was investigated in an IL-6-treated Caco-2 cell line using chromatin immunoprecipitation assays. RESULTS: IL-6 concentrations increased significantly in the colon tissues of DSS-treated mice. sgp130Fc or si-S100A9 administration to DSS-treated mice reduced granulocyte infiltration in CECs and induced the down-regulation of S100A9 and colitis disease activity. Treatment with STAT3 inhibitors upon IL-6 stimulation in the Caco-2 cell line demonstrated that IL-6 mediated S100A9 expression through STAT3 activation. Moreover, we found that phospho-STAT3 binds directly to the S100A9 promoter. S100A9 may recruit immune cells into inflamed colon tissues. CONCLUSIONS: Elevated S100A9 expression in CECs mediated by an IL-6/STAT3 signaling cascade may play an important role in the development of colitis.

  17. IL-17 induces AKT-dependent IL-6/JAK2/STAT3 activation and tumor progression in hepatocellular carcinoma

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    Gu Fang-Ming

    2011-12-01

    Full Text Available Abstract Background The Th17 subset and IL-17 have been found in increased frequencies within certain tumors. However, their relevance in cancer biology remains controversial. This study aimed to clarify the biological action of IL-17 on hepatocellular carcinoma (HCC. Methods Effects and underlying molecular mechanisms of IL-17 on human HCC were explored in vitro using exogenous IL-17 stimulation and in nude mice by implanting IL-17 overexpressed HCC cells. The clinical significance of IL-17 was investigated in tissue microarrays containing HCC tissues from 323 patients following hepatectomy using immunohistochemistry. Results Although exogenous IL-17 showed no direct effect on the growth rate of HCC cells in vitro, PCR and ELISA showed that IL-17 selectively augmented the secretion of diverse proinvasive factors and transwell showed a direct promotion of invasion of HCC cells by IL-17. Furthermore, transfection of IL-17 into HCC cells significantly promoted neoangiogenesis, neutrophil recruitment and tumor growth in vivo. Using siRNA mediated knockdown of AKT and STAT3, we suggested that the effects of IL-17 were operated through activation of the AKT signaling in HCC, which resulted in IL-6 production. Then, IL-6 in turn activated JAK2/STAT3 signaling and subsequently up-regulated its downstream targets IL-8, MMP2, and VEGF. Supporting these findings, in human HCC tissues, immunostaining indicated that IL-17 expression was significantly and positively associated with STAT3 phosphorylation, neutrophil infiltration and increased tumor vascularity. The clinical significance of IL-17 was authenticated by revealing that the combination of intratumoral IL-17+ cells and phospho-STAT3 served as a better prognosticator for postoperative tumor recurrence than either marker alone. Conclusions IL-17 mediated tumor-promoting role involves a direct effect on HCC cells through IL-6/JAK2/STAT3 induction by activating the AKT pathway.

  18. APPL1-mediated activation of STAT3 contributes to inhibitory effect of adiponectin on hepatic gluconeogenesis.

    Science.gov (United States)

    Ding, Youming; Zhang, Deling; Wang, Bin; Zhang, Yemin; Wang, Lei; Chen, Xiaoyan; Li, Mingxin; Tang, Zhao; Wang, Changhua

    2016-09-15

    Adiponectin has been shown to suppress hepatic gluconeogenesis. However, the signaling pathways underlying its action remain ill-defined. The purpose of this study was to examine the potential role of APPL1 in mediating anti-gluconeogenic ability of adiponectin. Primary hepatocytes were isolated from male C57BL/6 mice. Western blot and RT-PCR were performed to detect protein expression and mRNA level, respectively. The protein-protein association was determined by immunoprecipitation and GST pull-down assay. We found that APPL1 protein levels were negatively associated with expressions of proteins and mRNAs of gluconeogenesis enzymes under stimulation with adiponectin. In addition, adiponectin-stimulated STAT3 phosphorylation and acetylation were positively regulated by APPL1 and negative regulated by SirT1. Pharmacological and genetic inhibition of STAT3 mitigated impact of adiponectin on hepatic gluconeogenesis. Furthermore, adiponectin administration facilitated the binding of APPL1 to SirT1 and suppressed the association of SirT1 with STAT3. Taken together, our study showed that APPL1-SirT1-STAT3 pathway mediated adiponectin signaling in primary hepatocytes. This new finding provides a novel mechanism by which adiponectin suppresses hepatic gluconeogenesis. PMID:27246173

  19. Signal transducers and activators of transcription 3 (STAT3) inhibits transcription of the inducible nitric oxide synthase gene by interacting with nuclear factor kappaB.

    Science.gov (United States)

    Yu, Zhiyuan; Zhang, Wenzheng; Kone, Bruce C

    2002-01-01

    Prolific generation of NO by inducible nitric oxide synthase (iNOS) can cause unintended injury to host cells during glomerulonephritis and other inflammatory diseases. While much is known about the mechanisms of iNOS induction, few transcriptional repressors have been found. We explored the role of signal transducers and activators of transcription 3 (STAT3) proteins in interleukin (IL)-1beta- and lipopolysaccharide (LPS)+interferon (IFN)-gamma-mediated iNOS induction in murine mesangial cells. Both stimuli induced rapid phosphorylation of STAT3 and sequence-specific STAT3 DNA-binding activity. Supershift assays with a STAT3 element probe demonstrated that nuclear factor kappaB (NF-kappaB) p65 and p50 complexed with STAT3 in the DNA-protein complex. The direct interaction of STAT3 and NF-kappaB p65 was verified in vivo by co-immunoprecipitation and in vitro by pull-down assays with glutathione S-transferase-NF-kappaB p65 fusion protein and in vitro -translated STAT3alpha. Overexpression of STAT3 dramatically inhibited IL-1beta- or LPS+IFN-gamma-mediated induction of iNOS promoter-luciferase constructs that contained the wild-type iNOS promoter or ones harbouring mutated STAT-binding elements. In tests of indirect inhibitory effects of STAT3, overexpression of STAT3 dramatically inhibited the activity of an NF-kappaB-dependent promoter devoid of STAT-binding elements without affecting NF-kappaB DNA-binding activity. Thus STAT3, via direct interactions with NF-kappaB p65, serves as a dominant-negative inhibitor of NF-kappaB activity to suppress indirectly cytokine induction of the iNOS promoter in mesangial cells. These results provide a new model for the termination of NO production by activated iNOS following exposure to pro-inflammatory stimuli. PMID:12057007

  20. Activation of STAT3 signaling in human stomach adenocarcinoma drug-resistant cell line and its relationship with expression of vascular endothelial growth factor

    Institute of Scientific and Technical Information of China (English)

    Li-Fen Yu; Ying Cheng; Min-Min Qiao; Yong-Ping Zhang; Yun-Lin Wu

    2005-01-01

    AIM: To investigate the difference in activation of STAT3signaling between two human stomach adenocarcinoma cell lines: 5-fluorouracil resistant cell line and its parental cell line, and to evaluate its relationship with the expression of vascular endothelial growth factor (VEGF).METHODS: Western blot and electrophoretic mobility shift assay (EMSA) were used to detect the expression of phospho-STAT3 protein and constitutive activation of STAT3in two human stomach adenocarcinoma cell lines, 5-fluorouracil resistant cell line SGC7901/R and its parental cell line SGC7901, respectively. The mRNA expression of VEGF was analysed by semi-quantitative RT-PCR. The expressive intensity of VEGF protein was measured by immunocytochemistry.RESULTS: The expressions of phospho-STAT3 protein and constitutive activation of ST AT3 between two human stomach adenocarcinoma cell lines were different.Compared with the parental cell line SGC7901, the STAT3-DNA binding activity and the expressive intensity of phospho-STAT3 protein were lower in the drug-resistant cell line SGC7901/R. The expression levels of VEGF mRNA and its encoded protein were also decreased in drugresistant cell line.CONCLUSION: Over-expression of VEGF may be correlated with elevated STAT3 activation in parental cell line. Lower VEGF expression may be correlated with decreased STAT3activation in resistant cell line, which may have resulted from negative feedback regulation of STAT signaling.

  1. Activation of the interleukin-6/Janus kinase/STAT3 pathway in pleomorphic adenoma of the parotid gland

    DEFF Research Database (Denmark)

    Andreasen, Simon; Therkildsen, Marianne Hamilton; Grauslund, Morten;

    2015-01-01

    The interleukin-6 (IL-6)/Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) pathway is of crucial importance in promoting tumorigenesis in several malignant tumors but may also be active in benign tumors, e.g., of pleomorphic adenoma (PA). In this study we characterize...... reverse transcription-polymerase chain reaction (RT-PCR). Using immunohistochemistry, IL-6, JAK1, JAK2 and STAT3 were detected significantly more frequently in PA cells than in cells from normal salivary gland tissue. Using RT-PCR cyclin D1, fibroblast growth factor 2, and p21 were found...... to be overexpressed while matrix metallopeptidase 9 was detected at low levels in PA compared to normal salivary gland. ISH showed significant overexpression of miR-181b in PA, while miR-21 was undetectable in PA and normal tissue. Overexpression of the pathway components and its mRNA and miRNA products provide...

  2. Berberine suppresses tumorigenicity and growth of nasopharyngeal carcinoma cells by inhibiting STAT3 activation induced by tumor associated fibroblasts

    OpenAIRE

    Tsang, Chi Man; Cheung, Yuk Chun; Lui, Vivian Wai-Yan; Yip, Yim Ling; Zhang, Guitao; Lin, Victor Weitao; Cheung, Kenneth Chat-Pan; Feng, Yibin; Tsao, Sai Wah

    2013-01-01

    BACKGROUND: Cortidis rhizoma (Huanglian) and its major therapeutic component, berberine, have drawn extensive attention in recent years for their anti-cancer properties. Growth inhibitory effects of berberine on multiple types of human cancer cells have been reported. Berberine inhibits invasion, induces cell cycle arrest and apoptosis in human cancer cells. The anti-inflammatory property of berberine, involving inhibition of Signal Transducer and Activator of Transcription 3 (STAT3) activati...

  3. Crosstalk between signaling pathways of adrenoreceptors and signal transducers and activators of transcription 3 (STAT3) in heart

    Institute of Scientific and Technical Information of China (English)

    Kai-zheng GONG; Hui ZHANG; Jian-hai DU; You-yi ZHANG

    2007-01-01

    Recently, there have been important advancements in our understanding of the signaling mechanisms of adrenoreceptors (AR) and signal transducers and activators of transcription 3 (STAT3). While their crucial roles in the pathological processes of the heart are well established, accumulating evidence suggests there is a complex pattern of crosstalk between these 2 signaling pathways. Moreover, the potential for crosstalk occurs at multiple levels in each signaling cascade and involves receptor transactivation, G proteins, small GTPases, cyclic adenosine 3',5'-monophosphate/protein kinase A, protein kinase C, scaffold/adaptor proteins, protein tyrosine kinases, and mitogen-activated protein kinases. In addition, post-translational modification (eg acetylation) of STAT3 may provide a link betweenSTAT3 and AR signaling. In particular, crosstalk between these 2 systems in the heart would appear to be dependent upon the species/tissue studied, develop-mental stage, and eliciting stimulus. This at least partly accounts for the epigenetic effects on biological function that is mediated by the 2 signaling pathways. Elucidation of these mechanisms will provide new targets in the development of novel clinical strategies for heart disorders.

  4. LGR5 expression is controled by IKKα in basal cell carcinoma through activating STAT3 signaling pathway

    Science.gov (United States)

    Xiao, Deshen; Lai, Weiwei; Pan, Yu; Jiang, Yiqun; Chen, Ling; Mao, Chao; Zhou, Jian; Xi, Sichuan; Cao, Ya; Liu, Shuang; Tao, Yongguang

    2016-01-01

    Basal cell carcinomas (BCC) of the skin are the most common of human cancers. The noncanonical NF-κB pathway is dependent on IKKα. However, the role of IKKα in BCC has not been elucidated. We show here that IKKα is expressed in the nucleus in BCC and non-malignant diseases. Nuclear IKKα could directly bind to the promoters of inflammation factors and LGR5, a stem cell marker, in turn, upregulating LGR5 expression through activation of STAT3 signaling pathway during cancer progression. Activation of STAT3 signaling pathway contributes LGR5 expression in dependent of IKKα after the interplay between STAT3 and IKKα. Meanwhile knockdown of IKKα inhibits tumor growth and transition of epithelial stage to mescheme stage. Taken together, we demonstrate that IKKα functions as a bone fide chromatin regulator in BCC, whose promoted expression contributes to oncogenic transformation via promoting expression stemness- and inflammatory- related genes. Our finding reveals a novel viewpoint for how IKKα may involve in BCCs tumor progression in the inflammatory microenvironment. PMID:27049829

  5. Phosphorylated heat shock protein 27 promotes lipid clearance in hepatic cells through interacting with STAT3 and activating autophagy.

    Science.gov (United States)

    Shen, Lei; Qi, Zhilin; Zhu, Yanyan; Song, Xiaomeng; Xuan, Chunxia; Ben, Peiling; Lan, Lei; Luo, Lan; Yin, Zhimin

    2016-08-01

    Nonalcoholic fatty liver disease (NAFLD) has become the major liver disease worldwide. Recently, several studies have identified that the activation of autophagy attenuates hepatic steatosis. Heat shock protein 27 (Hsp27) is involved in autophagy in response to various stimuli. In this study, we demonstrate that phosphorylated Hsp27 stimulates autophagy and lipid droplet clearance and interacts with STAT3. In vivo study showed that high fat diet (HFD) feeding increased Hsp25 (mouse orthology of Hsp27) phosphorylation and autophagy in mouse livers. Inhibition of Hsp25 phosphorylation exacerbated HFD-induced hepatic steatosis in mice. In vitro study showed that palmitate-induced lipid overload in hepatic cells was enhanced by Hsp27 knockdown, KRIBB3 treatment and Hsp27-3A (non-phosphorylatable) overexpression but was prevented by Hsp27-WT (wild type) and Hsp27-3D (phosphomimetic) overexpression. Mechanism analysis demonstrated that palmitate could induce Hsp27 phosphorylation which promoted palmitate-induced autophagy. Phosphorylated Hsp27 interacted with STAT3 in response to palmitate treatment, and disrupted the STAT3/PKR complexes, facilitated PKR-dependent eIF2α phosphorylation, and thus stimulated autophagy. To conclude, our study provides a novel mechanism by which the phosphorylated Hsp27 promotes hepatic lipid clearance and suggests a new insight for therapy of steatotic diseases such as nonalcoholic fatty liver disease (NAFLD). PMID:27185187

  6. RKIP phosphorylation and STAT3 activation is inhibited by oxaliplatin and camptothecin and are associated with poor prognosis in stage II colon cancer patients

    International Nuclear Information System (INIS)

    A major obstacle in treating colorectal cancer (CRC) is the acquired resistance to chemotherapeutic agents. An important protein in the regulation of cancer cell death and clinical outcome is Raf kinase inhibitor protein (RKIP). In contrast, activated signal transducer and activator of transcription 3 (STAT3) is a protein that promotes tumor cell survival by inhibiting apoptosis and has an important role in cancer progression in many of cancer types. The aim of this study was to evaluate the regulation of RKIP and STAT3 after treatment with clinically relevant chemotherapeutic agents (camptothecin (CPT) and oxaliplatin (OXP)) and the cytokine interleukin-6 (IL-6) in HCT116 colon cancer cells as well as evaluate the association between RKIP and STAT3 with clinical outcome of Stage II colon cancer patients. HCT-116 colon cancer cells were treated with CPT, OXP, and IL-6 separately or in combination in a time and dose-dependent manner and examined for phosphorylated and non-phosphorylated RKIP and STAT3 via Western blot analysis. STAT3 transcriptional activity was measured via a luciferase reporter assay in HCT116 cells treated with CPT, IL-6 or transfected with JAK 1, 2 separately or in combination. We extended these observations and determined STAT3 and RKIP/ pRKIP in tumor microarrays (TMA) in stage II colon cancer patients. We demonstrate IL-6-mediated activation of STAT3 occurs in conjunction with the phosphorylation of RKIP in vitro in human colon cancer cells. OXP and CPT block IL-6 mediated STAT3 activation and RKIP phosphorylation via the inhibition of the interaction of STAT3 with gp130. We determined that STAT3 and nuclear pRKIP are significantly associated with poor patient prognosis in stage II colon cancer patients. In the analysis of tumor samples from stage II colon cancer patients and the human colon carcinoma cell line HCT116, pRKIP and STAT3, 2 proteins potentially involved in the resistance to conventional treatments were detected. The

  7. Novel thiosemicarbazones regulate the signal transducer and activator of transcription 3 (STAT3) pathway: inhibition of constitutive and interleukin 6-induced activation by iron depletion.

    Science.gov (United States)

    Lui, Goldie Y L; Kovacevic, Zaklina; V Menezes, Sharleen; Kalinowski, Danuta S; Merlot, Angelica M; Sahni, Sumit; Richardson, Des R

    2015-01-01

    Pharmacologic manipulation of metal pools in tumor cells is a promising strategy for cancer treatment. Here, we reveal how the iron-binding ligands desferrioxamine (DFO), di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT), and di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) inhibit constitutive and interleukin 6-induced activation of signal transducer and activator of transcription 3 (STAT3) signaling, which promotes proliferation, survival, and metastasis of cancer cells. We demonstrate that DFO, Dp44mT, and DpC significantly decrease constitutive phosphorylation of the STAT3 transcription factor at Tyr705 in the pancreatic cancer cell lines PANC-1 and MIAPaCa-2 as well as the prostate cancer cell line DU145. These compounds also significantly decrease the dimerized STAT3 levels, the binding of nuclear STAT3 to its target DNA, and the expression of downstream targets of STAT3, including cyclin D1, c-myc, and Bcl-2. Examination of upstream mediators of STAT3 in response to these ligands has revealed that Dp44mT and DpC could significantly decrease activation of the nonreceptor tyrosine kinase Src and activation of cAbl in DU145 and MIAPaCa-2 cells. In contrast to the effects of Dp44mT, DpC, or DFO on inhibiting STAT3 activation, the negative control compound di-2-pyridylketone 2-methyl-3-thiosemicarbazone, or the DFO:Fe complex, which cannot bind cellular iron, had no effect. This demonstrates the role of iron-binding in the activity observed. Immunohistochemical staining of PANC-1 tumor xenografts showed a marked decrease in STAT3 in the tumors of mice treated with Dp44mT or DpC compared with the vehicle. Collectively, these studies demonstrate suppression of STAT3 activity by iron depletion in vitro and in vivo, and reveal insights into regulation of the critical oncogenic STAT3 pathway. PMID:25561562

  8. A STAT3-mediated metabolic switch is involved in tumour transformation and STAT3 addiction

    NARCIS (Netherlands)

    Demaria, Marco; Giorgi, Carlotta; Lebiedzinska, Magdalena; Esposito, Giovanna; D'Angeli, Luca; Bartoli, Antonietta; Gough, Daniel J; Turkson, James; Levy, David E; Watson, Christine J; Wieckowski, Mariusz R; Provero, Paolo; Pinton, Paolo; Poli, Valeria

    2010-01-01

    The pro-oncogenic transcription factor STAT3 is constitutively activated in a wide variety of tumours that often become addicted to its activity, but no unifying view of a core function determining this widespread STAT3-dependence has yet emerged. We show here that constitutively active STAT3 acts a

  9. Vorinostat Enhances Cytotoxicity of SN-38 and Temozolomide in Ewing Sarcoma Cells and Activates STAT3/AKT/MAPK Pathways.

    Directory of Open Access Journals (Sweden)

    Valerie B Sampson

    Full Text Available Histone deacetylase inhibitors (HDACi have been evaluated in patients with Ewing sarcoma (EWS but demonstrated limited activity. To better understand the potential for HDACi in EWS, we evaluated the combination of the HDACi vorinostat, with DNA damaging agents SN-38 (the active metabolite of irinotecan and topoisomerase 1 inhibitor plus the alkylating agent temozolomide (ST. Drugs were evaluated in sequential and simultaneous combinations in two EWS cell lines. Results demonstrate that cell viability, DNA damage and reactive oxygen species (ROS production are dependent on the sequence of drug administration. Enhanced cytotoxicity is exhibited in vitro in EWS cell lines treated with ST administered before vorinostat, which was modestly higher than concomitant treatment and superior to vorinostat administered before ST. Drug combinations downregulate cyclin D1 to induce G0/G1 arrest and promote apoptosis by cleavage of caspase-3 and PARP. When ST is administered before or concomitantly with vorinostat there is activation of STAT3, MAPK and the p53 pathway. In contrast, when vorinostat is administered before ST, there is DNA repair, increased AKT phosphorylation and reduced H2B acetylation. Inhibition of AKT using the small molecule inhibitor MK-2206 did not restore H2B acetylation. Combining ST with the dual ALK and IGF-1R inhibitor, AZD3463 simultaneously inhibited STAT3 and AKT to enhance the cytotoxic effects of ST and further reduce cell growth suggesting that STAT3 and AKT activation were in part mediated by ALK and IGF-1R signaling. In summary, potent antiproliferative and proapoptotic activity were demonstrated for ST induced DNA damage before or simultaneous with HDAC inhibition and cell death was mediated through the p53 pathway. These observations may aid in designing new protocols for treating pediatric patients with high-risk EWS.

  10. Sphingosine-1-phosphate enhances satellite cell activation in dystrophic muscles through a S1PR2/STAT3 signaling pathway.

    Directory of Open Access Journals (Sweden)

    Kenneth C Loh

    Full Text Available Sphingosine-1-phosphate (S1P activates a widely expressed family of G protein-coupled receptors, serves as a muscle trophic factor and activates muscle stem cells called satellite cells (SCs through unknown mechanisms. Here we show that muscle injury induces dynamic changes in S1P signaling and metabolism in vivo. These changes include early and profound induction of the gene encoding the S1P biosynthetic enzyme SphK1, followed by induction of the catabolic enzyme sphingosine phosphate lyase (SPL 3 days later. These changes correlate with a transient increase in circulating S1P levels after muscle injury. We show a specific requirement for SphK1 to support efficient muscle regeneration and SC proliferation and differentiation. Mdx mice, which serve as a model for muscular dystrophy (MD, were found to be S1P-deficient and exhibited muscle SPL upregulation, suggesting that S1P catabolism is enhanced in dystrophic muscle. Pharmacological SPL inhibition increased muscle S1P levels, improved mdx muscle regeneration and enhanced SC proliferation via S1P receptor 2 (S1PR2-dependent inhibition of Rac1, thereby activating Signal Transducer and Activator of Transcription 3 (STAT3, a central player in inflammatory signaling. STAT3 activation resulted in p21 and p27 downregulation in a S1PR2-dependent fashion in myoblasts. Our findings suggest that S1P promotes SC progression through the cell cycle by repression of cell cycle inhibitors via S1PR2/STAT3-dependent signaling and that SPL inhibition may provide a therapeutic strategy for MD.

  11. IL-10-Mediated Tristetraprolin Induction is part of a feedback loop that controls Macrophage STAT3 activation and cytokine production1

    OpenAIRE

    Gaba, Anthony; Grivennikov, Sergei I; Do, Mahn Vu; Stumpo, Deborah J.; Blackshear, Perry J.; Karin, Michael

    2012-01-01

    In activated macrophages, the anti-inflammatory cytokine IL-10 inhibits expression of molecules that propagate inflammation in a manner that depends on transcription factor STAT3. Expression of IL-10 is regulated post-transcriptionally by the RNA-binding protein tristetraprolin (TTP), which destabilizes IL-10 mRNA in activated macrophages. Using LPS-activated bone marrow-derived murine macrophages, we demonstrate that TTP is a negative regulator of the IL-10/STAT3 anti-inflammatory response. ...

  12. Stat3 inhibition in neural lineage cells.

    Science.gov (United States)

    Chiba, Tomohiro; Mack, Laura; Delis, Natalia; Brill, Boris; Groner, Bernd

    2012-06-01

    Abstract Deregulation of signal transducer and activator of transcription 3 (Stat3) is attracting attentions in neurological disorders of elderly populations, e.g., Stat3 is inactivated in hippocampal neurons of Alzheimer's disease (AD) brains, whereas it is often constitutively activated in glioblastoma multiforme (GBM), correlating with poor prognosis. Stat3-inhibiting drugs have been intensively developed for chemotherapy based on the fact that GBM, in many cases, are "addicted" to Stat3 activation. Stat3 inhibitors, however, potentially have unfavorable side effects on postmitotic neurons, normal permanent residents in the central nervous system. It is, therefore, of great importance to address detailed cellular responses of neural lineage cells including normal neurons, astrocytes, and neuronal/glial cancer cell lines to several classes of Stat3 inhibitors focusing on their effective concentrations. Here, we picked up five human and mouse cancer cell lines (Neuro-2a and SH-SY5Y neuroblastoma cell lines and Tu-9648, U-87MG, and U-373MG glioblastoma cell lines) and treated with various Stat3 inhibitors. Among them, Stattic, FLLL31, and resveratrol potently suppressed P-Stat3 and cell viability in all the tested cell lines. Stat3 knockdown or expression of dominant-negative Stat3 further sensitized cells to the inhibitors. Expression of familial AD-related mutant amyloid precursor protein sensitized neuronal cells, not glial cells, to Stat3 inhibitors by reducing P-Stat3 levels. Primary neurons and astrocytes also responded to Stat3 inhibitors with similar sensitivities to those observed in cancer cell lines. Thus, Stat3 inhibitors should be carefully targeted to GBM cells to avoid potential neurotoxicity leading to AD-like neuropsychiatric dysfunctions. PMID:25436682

  13. Constitutive activation of a slowly migrating isoform of Stat3 in mycosis fungoides: tyrphostin AG490 inhibits Stat3 activation and growth of mycosis fungoides tumor cell lines

    DEFF Research Database (Denmark)

    Nielsen, M; Kaltoft, K; Nordahl, M;

    1997-01-01

    Mycosis fungoides (MF) is a low-grade cutaneous T cell lymphoma of unknown etiology. In this report, the Jak/Stat (Janus kinase/signal transducer and activator of transcription) signaling pathway was investigated in tumor cell lines established from skin biopsy specimens from a patient with MF...

  14. Cancer-associated fibroblasts promote endometrial cancer growth via activation of interleukin-6/STAT-3/c-Myc pathway.

    Science.gov (United States)

    Subramaniam, Kavita S; Omar, Intan Sofia; Kwong, Soke Chee; Mohamed, Zahurin; Woo, Yin Ling; Mat Adenan, Noor Azmi; Chung, Ivy

    2016-01-01

    Cancer-associated fibroblasts (CAFs) secrete various pro-tumorigenic cytokines, yet the role of these cytokines in the progression of endometrial cancer remains unclear. We found that CAFs isolated from human endometrial cancer (EC) tissues secreted high levels of interleukin-6 (IL-6), which promotes EC cell proliferation in vitro. Neutralizing IL-6 in CAF-conditioned media reduced (47% inhibition) while IL-6 recombinant protein increased cell proliferation (~2.4 fold) of both EC cell lines and primary cultures. IL-6 receptors (IL-6R and gp130) were expressed only in EC epithelial cells but not in CAF, indicating a one-way paracrine signaling. In the presence of CAF-conditioned media, Janus kinase/signal transducers and activators of transcription (JAK/STAT3) pathway was activated in EC cells. Treatment with JAK and STAT3 specific inhibitors, AD412 and STATTIC, respectively, significantly abrogated CAF-mediated cell proliferation, indicating the role of IL-6 activation in EC cell proliferation. We further showed that one of STAT-3 target genes, c-Myc, was highly induced in EC cells after exposure to CAF-conditioned medium at both mRNA (>105-fold vs. control) and protein level (>2-fold vs. control). EC cell proliferation was dependent on c-Myc expression, as RNAi-mediated c-Myc down-regulation led to a significant 46% reduction in cell viability when compared with scrambled control. Interestingly, CAF-conditioned media failed to promote proliferation in EC cells with reduced c-Myc expression, suggesting that CAF-mediated cell proliferation was also dependent on c-Myc expression. Subcutaneous tumor xenograft model showed that EC cells grew at least 1.4 times larger when co-injected with CAF, when compared to those injected with EC cells alone. Mice injected with EC cells with down-regulated c-Myc expression, however, showed at least 2.5 times smaller tumor compared to those in control group. Notably, there was no increase of tumor size when co-injected with CAFs

  15. Active Components with Inhibitory Activities on IFN-γ/STAT1 and IL-6/STAT3 Signaling Pathways from Caulis Trachelospermi

    OpenAIRE

    Xiao-Ting Liu; Zhe-Xing Wang; Yu Yang; Lin Wang; Ruo-Feng Sun; Yi-Min Zhao; Neng-Jiang Yu

    2014-01-01

    Initial investigation for new active herbal extract with inhibiting activity on JAK/STAT signaling pathway revealed that the extract of Caulis Trachelospermi, which was separated by 80% alcohol extraction and subsequent HP-20 macroporous resin column chromatography, was founded to strongly inhibit IFN-γ-induced STAT1-responsive luciferase activity (IFN-γ/STAT1) with IC50 value of 2.43 μg/mL as well as inhibiting IL-6-induced STAT3-responsive luciferase activity (IL-6/STAT3) with IC50 value of...

  16. Increased DNA binding activity of NF-κB, STAT-3, SMAD3 and AP-1 in acutely damaged liver

    Institute of Scientific and Technical Information of China (English)

    Adriana Salazar-Montes; Luis Ruiz-Corro; Ana SandovaI-Rodriguez; Alberto Lopez-Reyes; Juan Armendariz-Borunda

    2006-01-01

    AIM: To investigate the role of genes and kinetics of specific transcription factors in liver regeneration, and to analyze the gene expression and the activity of some molecules crucially involved in hepatic regeneration.METHODS: USING gel-shift assay and RT-PCR,transcription factors, such as NF-κB, STAT-3, SMAD3and AP-1, and gene expression of inducible nitric oxide synthase (iNOS), hepatocyte growth factor (HGF) and c-met were analyzed in an animal model of chemically induced hepatectomy.RESULTS: Gene expression of HGF and its receptor c-met peaked at 3 h and 24 h after acute CCl4 intoxication. iNOS expression was only observed from 6 to 48 h.Transcriptional factor NF-κB had an early activation at 30min after acute liver damage. STAT-3 peaked 3 h postintoxication, while AP-1 displayed a peak of activation at 48 h. SMAD3 showed a high activity at all analyzed times.CONCLUSION: TNF-α and IL-6 play a central role in hepatic regeneration. These two molecules are responsible for triggering the cascade of events and switch-on of genes involved in cell proliferation, such as growth factors, kinases and cyclins which are direct participants of cell proliferation.

  17. Antiproliferative effect of gold(I compound auranofin through inhibition of STAT3 and telomerase activity in MDA-MB 231 human breast cancer cells

    Directory of Open Access Journals (Sweden)

    Nam-Hoon Kim

    2013-01-01

    Full Text Available Signal transducer and activator of transcription 3 (STAT3 andtelomerase are considered attractive targets for anticancertherapy. The in vitro anticancer activity of the gold(I compoundauranofin was investigated using MDA-MB 231 human breastcancer cells, in which STAT3 is constitutively active. In cellculture, auranofin inhibited growth in a dose-dependent manner,and N-acetyl-L-cysteine (NAC, a scavenger of reactive oxygenspecies (ROS, markedly blocked the effect of auranofin.Incorporation of 5-bromo-2’-deoxyuridine into DNA andanchorage-independent cell growth on soft agar were decreasedby auranofin treatment. STAT3 phosphorylation and telomeraseactivity were also attenuated in cells exposed to auranofin, butNAC pretreatment restored STAT3 phosphorylation andtelomerase activity in these cells. These findings indicate thatauranofin exerts in vitro antitumor effects in MDA-MB 231 cellsand its activity involves inhibition of STAT3 and telomerase.Thus, auranofin shows potential as a novel anticancer drug thattargets STAT3 and telomerase. [BMB Reports 2013; 46(1: 59-64

  18. NOX1 is responsible for cell death through STAT3 activation in hyperoxia and is associated with the pathogenesis of Acute Respiratory Distress Syndrome

    OpenAIRE

    Carnesecchi, Stephanie; Dunand-Sauthier, Isabelle; Zanetti, Filippo; Singovski, Grigory; Deffert, Christine; Donati, Yves; Cagarelli, Thomas; Pache, Jean-Claude; Krause, Karl-Heinz; Reith, Walter; Barazzone-Argiroffo, Constance

    2014-01-01

    Reactive oxygen species (ROS) contribute to alveolar cell death in Acute Respiratory Distress Syndrome (ARDS) and we previously demonstrated that NOX1-derived ROS contributed to hyperoxia-induced alveolar cell death in mice. The study investigates whether NOX1 expression is modulated in epithelial cells concomitantly to cell death and associated to STAT3 signaling in the exudative phase of ARDS. In addition, the role of STAT3 activation in NOX1-dependent epithelial cell death was confirmed by...

  19. Interferon-γ suppresses intestinal epithelial aquaporin-1 expression via Janus kinase and STAT3 activation.

    Directory of Open Access Journals (Sweden)

    Michael S Dicay

    Full Text Available Inflammatory bowel diseases are associated with dysregulated electrolyte and water transport and resultant diarrhea. Aquaporins are transmembrane proteins that function as water channels in intestinal epithelial cells. We investigated the effect of the inflammatory cytokine, interferon-γ, which is a major player in inflammatory bowel diseases, on aquaporin-1 expression in a mouse colonic epithelial cell line, CMT93. CMT93 monolayers were exposed to 10 ng/mL interferon-γ and aquaporin-1 mRNA and protein expressions were measured by real-time PCR and western blot, respectively. In other experiments, CMT93 cells were pretreated with inhibitors or were transfected with siRNA to block the effects of Janus kinases, STATs 1 and 3, or interferon regulatory factor 2, prior to treatment with interferon-γ. Interferon-γ decreased aquaporin-1 expression in mouse intestinal epithelial cells in a manner that did not depend on the classical STAT1/JAK2/IRF-1 pathway, but rather, on an alternate Janus kinase (likely JAK1 as well as on STAT3. The pro-inflammatory cytokine, interferon-γ may contribute to diarrhea associated with intestinal inflammation in part through regulation of the epithelial aquaporin-1 water channel via a non-classical JAK/STAT receptor signalling pathway.

  20. 乳腺癌中肿瘤相关巨噬细胞STAT3激活与多种细胞因子及预后因素有关%STAT3 activation of tumor-associated macrophages is associated with cytokines of tumor microenvironment and prognostic factors in breast cancer

    Institute of Scientific and Technical Information of China (English)

    Zhengkui Sun; Shengchun Liu; Zhenxiang Yao

    2009-01-01

    Objective: The aim of this study was to investigate the correlation of STAT3 activation of tumor-associated macrophages (TAMs) and local cytokines (IL-β, TNF-α, TGF-β and IL-12) and prognostic factors in breast cancer. Methods: TAMs in 50 primary breast cancers and macrophages in 15 normal breasts were examined by immunohistochemistry. And STAT3 DNA-binding activity of TAMs in 33/50 primary breast cancers was measured by transcription factor DNA-binding ELISA. In addition, the concentrations of IL-β, TNF-α, TGF-β and IL-12 were measured in the 33 primary breast cancers extracts by ELISA. The correlation between STAT3 activity of TAMs and concentrations of IL-β, TNF-α, TGF-β and IL-12 were analyzed. The correlation between STAT3 activity of TAMs and conventional clinicopathologic parameters were also evaluated. Results: The macrophages density showed a significant increase in primary breast cancers compared to normal breasts. STAT3 DNA-binding activity of TAMs in breast cancer was significantly higher than that of monocytes/macrophages from peripheral blood of the patients. Furthermore, STAT3 activity of TAMs was correlated significantly with the levels of IL-β, TNF-α, TGF-β in breast cancer tissues. But an inverse association was observed between STAT3 activity of TAMs andIL-12. In addition, STAT3 activity of TAMs was higher in high histological type than in low histological type, and STAT3 activity of TAMs was higher in CerBb-2 positive than CerBb-2 negative. Conclusion: STAT3 activation of TAMs may be associate with increasing of IL-β, TNF-αand TGF-β and decreasing of IL-12 in breast cancer. STAT3 activation of TAMs may also be correlated with histological grade and CerBb-2 status of breast cancer.

  1. Identification of canonical tyrosine-dependent and non-canonical tyrosine-independent STAT3 activation sites in the intracellular domain of the interleukin 23 receptor.

    Science.gov (United States)

    Floss, Doreen M; Mrotzek, Simone; Klöcker, Tobias; Schröder, Jutta; Grötzinger, Joachim; Rose-John, Stefan; Scheller, Jürgen

    2013-07-01

    Signaling of interleukin 23 (IL-23) via the IL-23 receptor (IL-23R) and the shared IL-12 receptor β1 (IL-12Rβ1) controls innate and adaptive immune responses and is involved in the differentiation and expansion of IL-17-producing CD4(+) T helper (TH17) cells. Activation of signal transducer and activator of transcription 3 (STAT3) appears to be the major signaling pathway of IL-23, and STAT binding sites were predicted in the IL-23R but not in the IL-12Rβ1 chain. Using site-directed mutagenesis and deletion variants of the murine and human IL-23R, we showed that the predicted STAT binding sites (pYXXQ; including Tyr-504 and Tyr-626 in murine IL-23R and Tyr-484 and Tyr-611 in human IL-23R) mediated STAT3 activation. Furthermore, we identified two uncommon STAT3 binding/activation sites within the murine IL-23R. First, the murine IL-23R carried the Y(542)PNFQ sequence, which acts as an unusual Src homology 2 (SH2) domain-binding protein activation site of STAT3. Second, we identified a non-canonical, phosphotyrosine-independent STAT3 activation motif within the IL-23R. A third predicted site, Tyr-416 in murine and Tyr-397 in human IL-23R, is involved in the activation of PI3K/Akt and the MAPK pathway leading to STAT3-independent proliferation of Ba/F3 cells upon stimulation with IL-23. In contrast to IL-6-induced short term STAT3 phosphorylation, cellular activation by IL-23 resulted in a slower but long term STAT3 phosphorylation, indicating that the IL-23R might not be a major target of negative feedback inhibition by suppressor of cytokine signaling (SOCS) proteins. In summary, we characterized IL-23-dependent signal transduction with a focus on STAT3 phosphorylation and identified canonical tyrosine-dependent and non-canonical tyrosine-independent STAT3 activation sites in the IL-23R.

  2. FoxM1 Drives a Feed-forward STAT3-activation Signaling Loop that Promotes the Self-renewal and Tumorigenicity of Glioblastoma Stem-like Cells

    Science.gov (United States)

    Gong, Ai-hua; Wei, Ping; Zhang, Sicong; Yao, Jun; Yuan, Ying; Zhou, Ai-dong; Lang, Frederick F.; Heimberger, Amy B.; Rao, Ganesh; Huang, Suyun

    2015-01-01

    The growth factor PDGF controls the development of glioblastoma (GBM) but its contribution to the function of GBM stem-like cells (GSC) has been little studied. Here we report that the transcription factor FoxM1 promotes PDGFA-STAT3 signaling to drive GSC self-renewal and tumorigenicity. In GBM we found a positive correlation between expression of FoxM1 and PDGF-A. In GSC and mouse neural stem cells, FoxM1 bound to the PDGF-A promoter to upregulate PDGF-A expression, acting to maintain the stem-like qualities of GSC in part through this mechanism. Analysis of the human cancer genomic database TCGA revealed that GBM express higher levels of STAT3, a PDGF-A effector signaling molecule, as compared with normal brain. FoxM1 regulated STAT3 transcription through interactions with the β-catenin/TCF4 complex. FoxM1 deficiency inhibited PDGF-A and STAT3 expression in neural stem cells and GSC, abolishing their stem-like and tumorigenic properties. Further mechanistic investigations defined a FoxM1-PDGFA-STAT3 feed-forward pathway that was sufficient to confer stem-like properties to glioma cells. Collectively, our findings showed how FoxM1 activates expression of PDGF-A and STAT3 in a pathway required to maintain the self-renewal and tumorigenicity of glioma stem-like cells. PMID:25832656

  3. Active components with inhibitory activities on IFN-γ/STAT1 and IL-6/STAT3 signaling pathways from Caulis Trachelospermi.

    Science.gov (United States)

    Liu, Xiao-Ting; Wang, Zhe-Xing; Yang, Yu; Wang, Lin; Sun, Ruo-Feng; Zhao, Yi-Min; Yu, Neng-Jiang

    2014-01-01

    Initial investigation for new active herbal extract with inhibiting activity on JAK/STAT signaling pathway revealed that the extract of Caulis Trachelospermi, which was separated by 80% alcohol extraction and subsequent HP-20 macroporous resin column chromatography, was founded to strongly inhibit IFN-γ-induced STAT1-responsive luciferase activity (IFN-γ/STAT1) with IC50 value of 2.43 μg/mL as well as inhibiting IL-6-induced STAT3-responsive luciferase activity (IL-6/STAT3) with IC50 value of 1.38 μg/mL. Subsequent study on its active components led to the isolation and identification of two new dibenzylbutyrolactone lignans named 4-demethyltraxillaside (1) and nortrachelogenin 4-O-β-D-glucopyranoside (2), together with six known compounds. The lignan compounds 1-4 together with other lignan compounds isolated in previous study were tested the activities on IFN-γ/STAT1 and IL-6/STAT3 pathways. The following result showed that the main components trachelogenin and arctigenin had corresponding activities on IFN-γ/STAT1 pathway with IC50 values of 3.14 μM and 9.46 μM as well as trachelogenin, arctigenin and matairesinol strongly inhibiting IL-6/STAT3 pathway with IC50 values of 3.63 μM, 6.47 μM and 2.92 μM, respectively. PMID:25100250

  4. Active Components with Inhibitory Activities on IFN-γ/STAT1 and IL-6/STAT3 Signaling Pathways from Caulis Trachelospermi

    Directory of Open Access Journals (Sweden)

    Xiao-Ting Liu

    2014-08-01

    Full Text Available Initial investigation for new active herbal extract with inhibiting activity on JAK/STAT signaling pathway revealed that the extract of Caulis Trachelospermi, which was separated by 80% alcohol extraction and subsequent HP-20 macroporous resin column chromatography, was founded to strongly inhibit IFN-γ-induced STAT1-responsive luciferase activity (IFN-γ/STAT1 with IC50 value of 2.43 μg/mL as well as inhibiting IL-6-induced STAT3-responsive luciferase activity (IL-6/STAT3 with IC50 value of 1.38 μg/mL. Subsequent study on its active components led to the isolation and identification of two new dibenzylbutyrolactone lignans named 4-demethyltraxillaside (1 and nortrachelogenin 4-O-β-d-glucopyranoside (2, together with six known compounds. The lignan compounds 1–4 together with other lignan compounds isolated in previous study were tested the activities on IFN-γ/STAT1 and IL-6/STAT3 pathways. The following result showed that the main components trachelogenin and arctigenin had corresponding activities on IFN-γ/STAT1 pathway with IC50 values of 3.14 μM and 9.46 μM as well as trachelogenin, arctigenin and matairesinol strongly inhibiting IL-6/STAT3 pathway with IC50 values of 3.63 μM, 6.47 μM and 2.92 μM, respectively.

  5. Monoclonal Antibodies Specific for STAT3β Reveal Its Contribution to Constitutive STAT3 Phosphorylation in Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bharadwaj, Uddalak; Kasembeli, Moses M.; Eckols, T. Kris; Kolosov, Mikhail; Lang, Paul [Section of Infectious Disease, Department of Medicine, Baylor College of Medicine, Houston, TX 77030 (United States); Christensen, Kurt [Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX 77030 (United States); Edwards, Dean P. [Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX 77030 (United States); Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030 (United States); Tweardy, David J., E-mail: dtweardy@bcm.edu [Section of Infectious Disease, Department of Medicine, Baylor College of Medicine, Houston, TX 77030 (United States); Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX 77030 (United States); Department of Biochemistry & Molecular Biology, BCM 286, Room N-1319, Baylor College of Medicine, Houston, TX 77030 (United States)

    2014-09-29

    Since its discovery in mice and humans 19 years ago, the contribution of alternatively spliced Stat3, Stat3β, to the overall functions of Stat3 has been controversial. Tyrosine-phosphorylated (p) Stat3β homodimers are more stable, bind DNA more avidly, are less susceptible to dephosphorylation, and exhibit distinct intracellular dynamics, most notably markedly prolonged nuclear retention, compared to pStat3α homodimers. Overexpression of one or the other isoform in cell lines demonstrated that Stat3β acted as a dominant-negative of Stat3α in transformation assays; however, studies with mouse strains deficient in one or the other isoform indicated distinct contributions of Stat3 isoforms to inflammation. Current immunological reagents cannot differentiate Stat3β proteins derived from alternative splicing vs. proteolytic cleavage of Stat3α. We developed monoclonal antibodies that recognize the 7 C-terminal amino acids unique to Stat3β (CT7) and do not cross-react with Stat3α. Immunoblotting studies revealed that levels of Stat3β protein, but not Stat3α, in breast cancer cell lines positively correlated with overall pStat3 levels, suggesting that Stat3β may contribute to constitutive Stat3 activation in this tumor system. The ability to unambiguously discriminate splice alternative Stat3β from proteolytic Stat3β and Stat3α will provide new insights into the contribution of Stat3β vs. Stat3α to oncogenesis, as well as other biological and pathological processes.

  6. Monoclonal Antibodies Specific for STAT3β Reveal Its Contribution to Constitutive STAT3 Phosphorylation in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Uddalak Bharadwaj

    2014-09-01

    Full Text Available Since its discovery in mice and humans 19 years ago, the contribution of alternatively spliced Stat3, Stat3β, to the overall functions of Stat3 has been controversial. Tyrosine-phosphorylated (p Stat3β homodimers are more stable, bind DNA more avidly, are less susceptible to dephosphorylation, and exhibit distinct intracellular dynamics, most notably markedly prolonged nuclear retention, compared to pStat3α homodimers. Overexpression of one or the other isoform in cell lines demonstrated that Stat3β acted as a dominant-negative of Stat3α in transformation assays; however, studies with mouse strains deficient in one or the other isoform indicated distinct contributions of Stat3 isoforms to inflammation. Current immunological reagents cannot differentiate Stat3β proteins derived from alternative splicing vs. proteolytic cleavage of Stat3α. We developed monoclonal antibodies that recognize the 7 C-terminal amino acids unique to Stat3β (CT7 and do not cross-react with Stat3α. Immunoblotting studies revealed that levels of Stat3β protein, but not Stat3α, in breast cancer cell lines positively correlated with overall pStat3 levels, suggesting that Stat3β may contribute to constitutive Stat3 activation in this tumor system. The ability to unambiguously discriminate splice alternative Stat3β from proteolytic Stat3β and Stat3α will provide new insights into the contribution of Stat3β vs. Stat3α to oncogenesis, as well as other biological and pathological processes.

  7. HIV-1-infected and immune-activated macrophages induce astrocytic differentiation of human cortical neural progenitor cells via the STAT3 pathway.

    Directory of Open Access Journals (Sweden)

    Hui Peng

    Full Text Available Diminished adult neurogenesis is considered a potential mechanism in the pathogenesis of HIV-1-associated dementia (HAD. In HAD, HIV-1-infected and immune-activated brain mononuclear phagocytes (MP; perivascular macrophages and microglia drive central nervous system (CNS inflammation and may alter normal neurogenesis. We previously demonstrated HIV-1-infected and lipopolysaccharide (LPS activated monocyte-derived macrophages (MDM inhibit human neural progenitor cell (NPC neurogenesis, while enhancing astrogliogenesis through the secretion of the inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α, in vitro and in vivo. Here we further test the hypothesis that HIV-1-infected/activated MDM promote NPC astrogliogenesis via activation of the transcription factor signal transducer and activator of transcription 3 (STAT3, a critical factor for astrogliogenesis. Our results show that LPS-activated MDM-conditioned medium (LPS-MCM and HIV-infected/LPS-activated MDM-conditioned medium (LPS+HIV-MCM induced Janus kinase 1 (Jak1 and STAT3 activation. Induction of the Jak-STAT3 activation correlated with increased glia fibrillary acidic protein (GFAP expression, demonstrating an induction of astrogliogenesis. Moreover, STAT3-targeting siRNA (siSTAT3 decreased MCM-induced STAT3 activation and NPC astrogliogenesis. Furthermore, inflammatory cytokines (including IL-6, IL-1β and TNF-α produced by LPS-activated and/or HIV-1-infected MDM may contribute to MCM-induced STAT3 activation and astrocytic differentiation. These observations were confirmed in severe combined immunodeficient (SCID mice with HIV-1 encephalitis (HIVE. In HIVE mice, siRNA control (without target sequence, sicon pre-transfected NPCs injected with HIV-1-infected MDM showed more astrocytic differentiation and less neuronal differentiation of NPCs as compared to NPC injection alone. siSTAT3 abrogated HIV-1-infected MDM-induced astrogliogenesis of injected NPCs. Collectively, these

  8. The novel curcumin analog FLLL32 decreases STAT3 DNA binding activity and expression, and induces apoptosis in osteosarcoma cell lines

    International Nuclear Information System (INIS)

    Curcumin is a naturally occurring phenolic compound shown to have a wide variety of antitumor activities; however, it does not attain sufficient blood levels to do so when ingested. Using structure-based design, a novel compound, FLLL32, was generated from curcumin. FLLL32 possesses superior biochemical properties and more specifically targets STAT3, a transcription factor important in tumor cell survival, proliferation, metastasis, and chemotherapy resistance. In our previous work, we found that several canine and human osteosarcoma (OSA) cell lines, but not normal osteoblasts, exhibit constitutive phosphorylation of STAT3. Compared to curcumin, we hypothesized that FLLL32 would be more efficient at inhibiting STAT3 function in OSA cells and that this would result in enhanced downregulation of STAT3 transcriptional targets and subsequent death of OSA cells. Human and canine OSA cells were treated with vehicle, curcumin, or FLLL32 and the effects on proliferation (CyQUANT®), apoptosis (SensoLyte® Homogeneous AMC Caspase- 3/7 Assay kit, western blotting), STAT3 DNA binding (EMSA), and vascular endothelial growth factor (VEGF), survivin, and matrix metalloproteinase-2 (MMP2) expression (RT-PCR, western blotting) were measured. STAT3 expression was measured by RT-PCR, qRT- PCR, and western blotting. Our data showed that FLLL32 decreased STAT3 DNA binding by EMSA. FLLL32 promoted loss of cell proliferation at lower concentrations than curcumin leading to caspase-3- dependent apoptosis, as evidenced by PARP cleavage and increased caspase 3/7 activity; this could be inhibited by treatment with the pan-caspase inhibitor Z-VAD-FMK. Treatment of OSA cells with FLLL32 decreased expression of survivin, VEGF, and MMP2 at both mRNA and protein levels with concurrent decreases in phosphorylated and total STAT3; this loss of total STAT3 occurred, in part, via the ubiquitin-proteasome pathway. These data demonstrate that the novel curcumin analog FLLL32 has biologic activity

  9. Stat3 and G-CSF-induced myeloid differentiation.

    Science.gov (United States)

    Chakraborty, A; Tweardy, D J

    1998-08-01

    Granulocyte colony-stimulating factor (G-CSF) is the cytokine critical for directing neutrophilic granulocyte differentiation. Early G-CSF signaling events in myeloid cells involves activation of STATs, proteins that serve the dual function of signal transduction and activation of transcription, especially the activation of Stat3. A dominant-negative mutant construct of Stat3 inhibited G-CSF-mediated neutrophilic differentiation indicating that Stat3 is a essential component for driving the G-CSF-mediated differentiation program in myeloid cells. Three isoforms of Stat3 have been identified, alpha(p92), beta(p83) and gamma(p72) each derived from a single gene. Stat3alpha is the predominant isoform expressed in most cells. Stat3beta is derived from Stat3alpha by alternative RNA splicing. Stat3gamma is derived from Stat3alpha by limited proteolysis. Mapping of Stat3alpha and Stat3beta activation in M1 murine myeloid leukemia cells revealed that their optimal activation required G-CSFR constructs containing both Y704 and Y744. These amino acid residues has previously been demonstrated to be essential for G-CSF-induced differentiation in this cells. Phosphopeptide affinity and phosphopeptide inhibition studies indicate that Stat3alpha and Stat3beta are recruited to the G-CSF receptor complex through their interaction with the receptor at phosphotyrosines Y704 and Y744. Y744 is followed at the +3 position by Cys (C). This sequence YXXC, represents a novel motif implicated in the recruitment and activation of Stat3alpha, Stat3beta and Stat3gamma by the hG-CSFR. Structurally, Stat3alpha, Stat3beta and Stat3gamma differ from each other in their C-terminal transactivation domain. In the beta isoform, the Stat3alpha transactivation domain is replaced by 7 amino acid residues which enable Stat3beta to interact with c-Jun. In the gamma isoform, the Stat3alpha transactivation domain is removed by limited proteolysis creating a dominant negative isoform. In immature human

  10. Inhibition of the STAT3 signaling pathway is involved in the antitumor activity of cepharanthine in SaOS2 cells

    Institute of Scientific and Technical Information of China (English)

    Zan CHEN; Chen HUANG; Yan-ling YANG; Yi DING; Han-qiang; OU-YANG; You-yi ZHANG; Ming XU

    2012-01-01

    To investigate the molecular mechanisms underlying the antitumor activity of cepharanthine (CEP),an alkaloid extracted from Stephania cepharantha Hayata.Methods:Human osteosarcoma cell line SaOS2 was used.MTT assay,Hoechst 33342 nuclear staining,flow cytometry,Western blotting and nude mouse xenografts of SaOS2 cells were applied to examine the antitumor activity of CEP in vitro and in vivo.The expression levels of STAT3 and its downstream signaling molecules were measured with Western blotting and immunochemistry analysis.The activity of STAT3 was detected based on the phosphorylation level of STAT3,luciferase gene reporter assay and translocation of STAT3 to the nucleus.Results:Treatment of SaOS2 cells with CEP (2.5-20 μmol/L) inhibited the cell growth in a concentration- and time-dependent manner.CEP (10 μmol/L) caused cell cycle arrest at G1 phase and induced apoptosis of SaOS2 cells.CEP (10 and 15 μmol/L) significantly decreased the expression of STAT3 in SaOS2 cells.Furthermore,CEP (5 and 10 μmol/L) significantly inhibited the expression of target genes of STAT3,including the anti-apoptotic gene Bcl-xL and the cell cycle regulators c-Myc and cyclin D1.In nude mouse xenografts of SaOS2 cells,CEP (20 mg·kg-1-d-1,ip for 19 d) significantly reduced the volume and weight of the tumor.Conclusion:Our findings suggest that inhibition of STAT3 signaling pathway is involved in the anti-tumor activity of CEP.

  11. Inhibition of STAT3 signaling and induction of SHP1 mediate antiangiogenic and antitumor activities of ergosterol peroxide in U266 multiple myeloma cells

    International Nuclear Information System (INIS)

    Ergosterol peroxide (EP) derived from edible mushroom has been shown to exert anti-tumor activity in several cancer cells. In the present study, anti-angiogenic activity of EP was investigated with the underlying molecular mechanisms in human multiple myeloma U266 cells. Despite weak cytotoxicity against U266 cells, EP suppressed phosphorylation, DNA binding activity and nuclear translocalization of signal transducer and activator of transcription 3 (STAT3) in U266 cells at nontoxic concentrations. Also, EP inhibited phosphorylation of the upstream kinases Janus kinase 2 (JAK2) and Src in a time-dependent manner. Furthermore, EP increased the expression of protein tyrosine phosphatase SHP-1 at protein and mRNA levels, and conversely silencing of the SHP-1 gene clearly blocked EP-mediated STAT3 inactivation. In addition, EP significantly decreased vascular endothelial growth factor (VEGF), one of STAT3 target genes at cellular and protein levels as well as disrupted in vitro tube formation assay. Moreover, EP significantly suppressed the growth of U266 cells inoculated in female BALB/c athymic nude mice and immunohistochemistry revealed that EP effectively reduced the expression of STAT3 and CD34 in tumor sections compared to untreated control. These findings suggest that EP can exert antitumor activity in multiple myeloma U266 cells partly with antiangiogenic activity targeting JAK2/STAT3 signaling pathway as a potent cancer preventive agent for treatment of multiple myeloma cells

  12. Photodynamic therapy activated STAT3 associated pathways: Targeting intrinsic apoptotic pathways to increase PDT efficacy in human squamous carcinoma cells.

    Science.gov (United States)

    Qiao, Li; Xu, Chengshan; Li, Qiang; Mei, Zhusong; Li, Xinji; Cai, Hong; Liu, Wei

    2016-06-01

    5-Aminolaevulinic acid-based photodynamic therapy (ALA-PDT) has been used for part of squamous cell carcinoma (premalignant conditions or in situ cutaneous SCC-Bowen disease). However, mechanism of ALA-PDT is not fully understood yet on the cell apoptosis pathway. The aim of this study was to further investigate the effect and mechanism of 5-ALA-PDT on human squamous carcinoma A431cells. Apoptosis and cell viability after PDT were evaluated using Annexin V-FITC apoptosis detection kit and MTT assay. The mRNA and protein levels were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. Our data showed that 5-ALA-PDT significantly inhibited cell proliferation (p<0.05), but there was no significant difference when the photosensitizer reached to 4.8mM. The inhibition in cell proliferation after 5-ALA-PDT treatment was correlated to more cells being arrested in the G0/G1 phase of the cell cycle (p<0.01). Immunocytochemical observations using anti-active caspase-3 antibodies showed active caspase-3 was translocated from cytoplasm to nuclear during apoptosis. STAT3 and its downstream gene Bax and BCL-2 were changed after 5-ALA-PDT treatment for the mRNA and protein expression. Our studies confirmed that 5-ALA-PDT might be an effective treatment for human squamous carcinoma by inhibiting the tumor cell A431growth and for the first time demonstrated that the expression of STAT3 was significantly reduced at 24h after 5-ALA-PDT treatment. PMID:26607555

  13. Inhibition of ALK enzymatic activity in T-cell lymphoma cells induces apoptosis and suppresses proliferation and STAT3 phosphorylation independently of Jak3

    DEFF Research Database (Denmark)

    Marzec, Michal; Kasprzycka, Monika; Ptasznik, Andrzej;

    2005-01-01

    Aberrant expression of the ALK tyrosine kinase as a chimeric protein with nucleophosmin (NPM) and other partners plays a key role in malignant cell transformation of T-lymphocytes and other cells. Here we report that two small-molecule, structurally related, quinazoline-type compounds, WHI-131...... and WHI-154, directly inhibit enzymatic activity of NPM/ALK as demonstrated by in vitro kinase assays using a synthetic tyrosine-rich oligopeptide and the kinase itself as the substrates. The inhibition of NPM/ALK activity resulted in malignant T cells in suppression of their growth, induction...... of apoptosis and inhibition of tyrosine phosphorylation of STAT3, the key effector of the NPM/ALK-induced oncogenesis. We also show that the STAT3 tyrosine phosphorylation is mediated in the malignant T cells by NPM/ALK independently of Jak3 kinase as evidenced by the presence of STAT3 phosphorylation...

  14. M-HIFU Inhibits Tumor Growth, Suppresses STAT3 Activity and Enhances Tumor Specific Immunity in a Transplant Tumor Model of Prostate Cancer

    OpenAIRE

    Xiaoyi Huang; Fang Yuan; Meihua Liang; Hui-Wen Lo; Shinohara, Mari L.; Cary Robertson; Pei Zhong

    2012-01-01

    OBJECTIVE: In this study, we explored the use of mechanical high intensity focused ultrasound (M-HIFU) as a neo-adjuvant therapy prior to surgical resection of the primary tumor. We also investigated the role of signal transducer and activator of transcription 3 (STAT3) in M-HIFU elicited anti-tumor immune response using a transplant tumor model of prostate cancer. METHODS: RM-9, a mouse prostate cancer cell line with constitutively activated STAT3, was inoculated subcutaneously in C57BL/6J m...

  15. A novel missense (M206K STAT3 mutation in diffuse large B cell lymphoma deregulates STAT3 signaling.

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    Guangzhen Hu

    Full Text Available Persistent STAT3 activation has been found in activated B-cell like diffuse large B cell tumors (DLBCL. To investigate whether genetic mutations play a role in aberrant STAT3 signaling in DLBCL, we bi-directionally sequenced all 24 exons of the STAT3 gene in DLBCL tumors (n = 40. We identified 2 novel point mutations in 2 separate (2/40; 5% patients at exon 7 and 24. Point mutation 2552G>A was a silent mutation in the stop codon. Another heterozygous mutation 857T>A encoded a methionine substitution by lysine at codon 206 (M206K in the coiled-coil domain of STAT3. We performed site directed mutagenesis to mutate wild type (WT STAT3α and STAT3β at codon 206 and constructed stable cell lines by lentiviral transfection of STAT3α(WT, STAT3α(M206K, STAT3β(WT and STAT3β(M206K plasmids. The mutation was found to increase STAT3 phosphorylation in STAT3α mutant cell lines with no effect on the STAT3β mutant cell line. Transcriptional activation was also increased in the STAT3α mutant cells compared with STAT3α WT cells as detected by a luciferase reporter assay. Moreover, STAT3α(M206K mutant cells were resistant to JAK2 pathway inhibition compared to STAT3α WT cells. These results indicate that missense mutations in STAT3 increase signaling through the JAK/STAT pathway. JAK2 inhibitors may be useful in the patient with this STAT3 mutation as well as those with pathway activation by other mechanisms.

  16. Modulatory role of phospholipase D in the activation of signal transducer and activator of transcription (STAT-3 by thyroid oncogenic kinase RET/PTC

    Directory of Open Access Journals (Sweden)

    Kim Dong Wook

    2008-05-01

    Full Text Available Abstract Background RET/PTC (rearranged in transformation/papillary thyroid carcinomas gene rearrangements are the most frequent genetic alterations identified in papillary thyroid carcinoma. Although it has been established that RET/PTC kinase plays a crucial role in intracellular signaling pathways that regulate cellular transformation, growth, and proliferation in thyroid epithelial cells, the upstream signaling that leads to the activation of RET/PTC is largely unknown. Based on the observation of high levels of PLD expression in human papillary thyroid cancer tissues, we investigated whether PLD plays a role in the regulating the RET/PTC-induced STAT3 activation. Methods Cancer tissue samples were obtained from papillary thyroid cancer patients (n = 6. The expression level of PLD was examined using immunohistochemistry and western blotting. Direct interaction between RET/PTC and PLD was analyzed by co-immunoprecipitation assay. PLD activity was assessed by measuring the formation of [3H]phosphatidylbutanol, the product of PLD-mediated transphosphatidylation, in the presence of n-butanol. The transcriptional activity of STAT3 was assessed by m67 luciferase reporter assay. Results In human papillary thyroid cancer, the expression levels of PLD2 protein were higher than those in the corresponding paired normal tissues. PLD and RET/PTC could be co-immunoprecipitated from cells where each protein was over-expressed. In addition, the activation of PLD by pervanadate triggered phosphorylation of tyrosine 705 residue on STAT-3, and its phosphorylation was dramatically higher in TPC-1 cells (from papillary carcinoma that have an endogenous RET/PTC1 than in ARO cells (from anaplastic carcinoma without alteration of total STAT-3 expression. Moreover, the RET/PTC-mediated transcriptional activation of STAT-3 was synergistically increased by over-expression of PLD, whereas the PLD activity as a lipid hydrolyzing enzyme was not affected by RET

  17. Peroxiredoxin 5 Protects TGF-β Induced Fibrosis by Inhibiting Stat3 Activation in Rat Kidney Interstitial Fibroblast Cells.

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    Hoon-In Choi

    Full Text Available Renal fibrosis is a common final pathway of end-stage kidney disease which is induced by aberrant accumulation of myofibroblasts. This process is triggered by reactive oxygen species (ROS and proinflammatory cytokines generated by various source of injured kidney cells. Peroxiredoxin 5 (Prdx5 is a thiol-dependent peroxidase that reduces oxidative stress by catalyzing intramolecular disulfide bonds. Along with its antioxidant effects, expression level of Prdx5 also was involved in inflammatory regulation by immune stimuli. However, the physiological effects and the underlying mechanisms of Prdx5 in renal fibrosis have not been fully characterized. Sprague-Dawley rats were subjected to unilateral ureteral obstruction (UUO for 1 or 7 days. For the in vitro model, NRK49F cells, a rat kidney interstitial fibroblast cell lines, were treated with transforming growth factor β (TGF-β for 0, 1, 3, or 5 days. To access the involvement of its peroxidase activity in TGF-β induced renal fibrosis, wild type Prdx5 (WT and double mutant Prdx5 (DM, converted two active site cysteines at Cys 48 and Cys 152 residue to serine, were transiently expressed in NRK49F cells. The protein expression of Prdx5 was reduced in UUO kidneys. Upregulation of fibrotic markers, such as fibronectin and alpha-smooth muscle actin (α-SMA, declined at 5 days in time point of higher Prdx5 expression in TGF-β treated NRK49F cells. The overexpression of wild type Prdx5 by transient transfection in NRK49F cells attenuated the TGF-β induced upregulation of fibronectin and α-SMA. On the other hand, the transient transfection of double mutant Prdx5 did not prevent the activation of fibrotic markers. Overexpression of Prdx5 also suppressed the TGF-β induced upregulation of Stat3 phosphorylation, while phosphorylation of Smad 2/3 was unchanged. In conclusion, Prdx5 protects TGF-β induced fibrosis in NRK49F cells by modulating Stat3 activation in a peroxidase activity dependent manner.

  18. pSTAT1, pSTAT3, and T-bet as markers of disease activity in chronic inflammatory demyelinating polyradiculoneuropathy.

    Science.gov (United States)

    Madia, Francesca; Frisullo, Giovanni; Nociti, Viviana; Conte, Amelia; Luigetti, Marco; Del Grande, Alessandra; Patanella, Agata Katia; Iorio, Raffaele; Tonali, Pietro Attilio; Batocchi, Anna Paola; Sabatelli, Mario

    2009-06-01

    Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is considered an auto-immune disorder. We evaluated expression of pSTAT1, T-bet, and pSTAT3 in circulating T-cells, B-cells, and monocytes and spontaneous production of interleukin-17 (IL17), interferon-gamma (IFN gamma), and interleukin-10 (IL10) by peripheral blood mononuclear cells (PBMCs) from 14 active CIDP patients compared with 6 patients with long-lasting remission and 20 controls. Active disease patients showed higher pSTAT1, T-bet, and pSTAT3 in CD4(+) T-cells than controls (p CIDP patients than controls (p = 0.0011, p = 0.0041, p = 0.0413, respectively) and remission patients (p = 0.0073, p = 0.0274, p = 0.0251, respectively). Moreover in CD8(+) T-cells, pSTAT3 expression was higher in active CIDP patients than in remission patients (p = 0.0345) and in controls (p = 0.0023). IL17 and IFN gamma production were significantly higher in active CIDP patients than in controls (p CIDP patients (p = 0.0073). IL10 levels were higher in active phase patients than in controls (p = 0.0334). Our data suggest that pSTAT1, T-bet, and pSTAT3 can be considered putative markers of disease activity and potential targets for specific therapies.

  19. MDM2 facilitates adipocyte differentiation through CRTC-mediated activation of STAT3.

    Science.gov (United States)

    Hallenborg, P; Siersbæk, M; Barrio-Hernandez, I; Nielsen, R; Kristiansen, K; Mandrup, S; Grøntved, L; Blagoev, B

    2016-06-30

    The ubiquitin ligase MDM2 is best known for balancing the activity of the tumor suppressor p53. We have previously shown that MDM2 is vital for adipocyte conversion through controlling Cebpd expression in a p53-independent manner. Here, we show that the proadipogenic effect of MDM2 relies on activation of the STAT family of transcription factors. Their activation was required for the cAMP-mediated induction of target genes. Interestingly, rather than influencing all cAMP-stimulated genes, inhibition of the kinases directly responsible for STAT activation, namely JAKs, or ablation of MDM2, each resulted in abolished induction of a subset of cAMP-stimulated genes, with Cebpd being among the most affected. Moreover, STATs were able to interact with the transcriptional cofactors CRTC2 and CRTC3, hitherto only reported to associate with the cAMP-responsive transcription factor CREB. Last but not least, the binding of CRTC2 to a transcriptional enhancer that interacts with the Cebpd promoter was dramatically decreased upon JAK inhibition. Our data reveal the existence of an unusual functional interplay between STATs and CREB at the onset of adipogenesis through shared CRTC cofactors.

  20. Stable expression of constitutively-activated STAT3 in benign prostatic epithelial cells changes their phenotype to that resembling malignant cells

    Directory of Open Access Journals (Sweden)

    Barton Arnold B

    2005-01-01

    Full Text Available Abstract Background Signal transducers and activators of transcription (STATs are involved in growth regulation of cells. They are usually activated by phosphorylation at specific tyrosine residues. In neoplastic cells, constitutive activation of STATs accompanies growth dysregulation and resistance to apoptosis through changes in gene expression, such as enhanced anti-apoptotic gene expression or reduced pro-apoptotic gene expression. Activated STAT3 is thought to play an important role in prostate cancer (PCA progression. Because we are interested in how persistently-activated STAT3 changes the cellular phenotype to a malignant one in prostate cancer, we used expression vectors containing a gene for constitutively-activated STAT3, called S3c, into NRP-152 rat and BPH-1 human benign prostatic epithelial cells. Results We observed that prostatic cell lines stably expressing S3c required STAT3 expression for survival, because they became sensitive to antisense oligonucleotide for STAT3. However, S3c-transfected cells were not sensitive to the effects of JAK inhibitors, meaning that STAT3 was constitutively-activated in these transfected cell lines. NRP-152 prostatic epithelial cells lost the requirement for exogenous growth factors. Furthermore, we observed that NRP-152 expressing S3c had enhanced mRNA levels of retinoic acid receptor (RAR-α, reduced mRNA levels of RAR-β and -γ, while BPH-1 cells transfected with S3c became insensitive to the effects of androgen, and also to the effects of a testosterone antagonist. Both S3c-transfected cell lines grew in soft agar after stable transfection with S3c, however neither S3c-transfected cell line was tumorigenic in severe-combined immunodeficient mice. Conclusions We conclude, based on our findings, that persistently-activated STAT3 is an important molecular marker of prostate cancer, which develops in formerly benign prostate cells and changes their phenotype to one more closely resembling

  1. Autocrine IL-10 activation of the STAT3 pathway is required for pathological macrophage differentiation in polycystic kidney disease

    Science.gov (United States)

    Peda, Jacqueline D.; Salah, Sally M.; Wallace, Darren P.; Fields, Patrick E.; Grantham, Connor J.; Fields, Timothy A.

    2016-01-01

    ABSTRACT Polycystic kidney disease (PKD) is characterized by slow expansion of fluid-filled cysts derived from tubules within the kidney. Cystic expansion results in injury to surrounding parenchyma and leads to inflammation, scarring and ultimately loss of renal function. Macrophages are a key element in this process, promoting cyst epithelial cell proliferation, cyst expansion and disease progression. Previously, we have shown that the microenvironment established by cystic epithelial cells can ‘program’ macrophages, inducing M2-like macrophage polarization that is characterized by expression of markers that include Arg1 and Il10. Here, we functionally characterize these macrophages, demonstrating that their differentiation enhances their ability to promote cyst cell proliferation. This observation indicates a model of reciprocal pathological interactions between cysts and the innate immune system: cyst epithelial cells promote macrophage polarization to a phenotype that, in turn, is especially efficient in promoting cyst cell proliferation and cyst growth. To better understand the genesis of this macrophage phenotype, we examined the role of IL-10, a regulatory cytokine shown to be important for macrophage-stimulated tissue repair in other settings. Herein, we show that the acquisition of the pathological macrophage phenotype requires IL-10 secretion by the macrophages. Further, we demonstrate a requirement for IL-10-dependent autocrine activation of the STAT3 pathway. These data suggest that the IL-10 pathway in macrophages plays an essential role in the pathological relationship between cysts and the innate immune system in PKD, and thus could be a potential therapeutic target. PMID:27491076

  2. SOCS3 Expression Correlates with Severity of Inflammation, Expression of Proinflammatory Cytokines, and Activation of STAT3 and p38 MAPK in LPS-Induced Inflammation In Vivo

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    João Antônio Chaves de Souza

    2013-01-01

    Full Text Available SOCS3 is an inducible endogenous negative regulator of JAK/STAT pathway, which is relevant in inflammatory conditions. We used a model of LPS-induced periodontal disease in rats to correlate SOCS3 expression with the inflammatory status. In vitro we used a murine macrophage cell line to assess the physical interaction between SOCS3 and STAT3 by coimmunoprecipitation. 30 ug of LPS from Escherichia coli were injected in the gingival tissues on the palatal aspect of first molars of the animals 3x/week for up to 4 weeks. Control animals were injected with the vehicle (PBS. The rats were sacrificed at 7, 15, and 30 days. Inflammation and gene expression were assessed by stereometric analysis, immunohistochemistry, RT-qPCR, and western blot. LPS injections increased inflammation, paralleled by an upregulation of SOCS3, of the proinflammatory cytokines IL-1β, IL-6, and TNF-α and increased phosphorylation of STAT3 and p38 MAPK. SOCS3 expression accompanied the severity of inflammation and the expression of proinflammatory cytokines, as well as the activation status of STAT3 and p38 MAPK. LPS stimulation in a macrophage cell line in vitro induced transient STAT3 activation, which was inversely correlated with a dynamic physical interaction with SOCS3, suggesting that this may be a mechanism for SOCS3 regulatory function.

  3. Activating transcription factor 4 mediates a multidrug resistance phenotype of esophageal squamous cell carcinoma cells through transactivation of STAT3 expression.

    Science.gov (United States)

    Zhu, Hongwu; Chen, Xiong; Chen, Bin; Chen, Bei; Fan, Jianyong; Song, Weibing; Xie, Ziying; Jiang, Dan; Li, Qiuqiong; Zhou, Meihua; Sun, Dayong; Zhao, Yagang

    2014-11-01

    Multidrug resistance (MDR) is a major challenge to the clinical treatment of esophageal cancer. The stress response gene activating transcription factor 4 (ATF4) is involved in homeostasis and cellular protection. However, relatively little is known about the expression and function of ATF4 in esophageal squamous cell carcinoma (ESCC) MDR. In this study, we investigate the potential role and mechanisms of ATF4 in ESCC MDR. We demonstrated that overexpression of ATF4 promotes the MDR phenotype in ESCC cells, while depletion of ATF4 in the MDR ESCC cell line induces drug re-sensitization. We also demonstrated that ATF4 transactivates STAT3 expression by directly binding to the signal transducers and activators of transcription 3 (STAT3) promoter, resulting in MDR in ESCC cells. Significantly, inhibition of STAT3 by small interfering RNA (siRNA) or a selective inhibitor (JSI-124) reintroduces therapeutic sensitivity. In addition, increased Bcl-2, survivin, and MRP1 expression levels were observed in ATF4-overexpressing cells. In conclusion, ATF4 may promote MDR in ESCC cells through the up-regulation of STAT3 expression, and thus is an attractive therapeutic target to combat therapeutic resistance in ESCC.

  4. STAT3 interacts directly with Hsp90.

    Science.gov (United States)

    Prinsloo, Earl; Kramer, Adam H; Edkins, Adrienne L; Blatch, Gregory L

    2012-03-01

    Heat shock protein 90 (Hsp90) functionally modulates signal transduction. The signal transducer and activator of transcription 3 (STAT3) mediates interleukin-6 family cytokine signaling. Aberrant activation and mutation of STAT3 is associated with oncogenesis and immune disorders, respectively. Hsp90 and STAT3 have previously been shown to colocalize and coimmunoprecipitate in common complexes. Surface plasmon resonance spectroscopy revealed a direct, high affinity specific interaction between recombinant Hsp90β and STAT3β in the presence and absence of adenosine triphosphate (ATP) in molar excess. Furthermore, comparative analysis using a phosphomimetic mutation at tyrosine 705 showed that the direct interaction appeared to favor neither unactivated nor activated STAT3. Destabilizing mutation of STAT3 at arginine residues 414/417 to alanine in the DNA-binding domain, previously shown to disrupt nuclear translocation in vivo, reduced interaction with a STAT3 DNA binding site oligonucleotide and Hsp90β in vitro, indicating that STAT3 requires a functional DNA-binding domain for full direct interaction with Hsp90. Site-directed mutagenesis of a mammalian STAT3-EGFP-N1 fusion construct at RR414/417 and subsequent transfection into human MCF7 epithelial breast cancer cells showed no impaired nuclear translocation when observed by confocal laser scanning microscopy. However, costaining for Hsp90α/β isoforms and colocalization analysis revealed a defined decrease in pixel-on-pixel colocalization compared with the wild-type confirming the requirement of the DNA-binding domain for high-affinity interaction. PMID:22271514

  5. leptin-induced growth stimulation of breast cancer cells involves recruitment of histone acetyltransferases and mediator complex to CYCLIN D1 promoter via activation of Stat3.

    Science.gov (United States)

    Saxena, Neeraj K; Vertino, Paula M; Anania, Frank A; Sharma, Dipali

    2007-05-01

    Numerous epidemiological studies documented that obesity is a risk factor for breast cancer development in postmenopausal women. Leptin, the key player in the regulation of energy balance and body weight control also acts as a growth factor on certain organs in both normal and disease state. In this study, we analyzed the role of leptin and the molecular mechanism(s) underlying its action in breast cancer cells that express both short and long isoforms of leptin receptor. Leptin increased MCF7 cell population in the S-phase of the cell cycle along with a robust increase in CYCLIN D1 expression. Also, leptin induced Stat3-phosphorylation-dependent proliferation of MCF7 cells as blocking Stat3 phosphorylation with a specific inhibitor, AG490, abolished leptin-induced proliferation. Using deletion constructs of CYCLIN D1 promoter and chromatin immunoprecipitation assay, we show that leptin induced increase in CYCLIN D1 promoter activity is mediated through binding of activated Stat3 at the Stat binding sites and changes in histone acetylation and methylation. We also show specific involvement of coactivator molecules, histone acetyltransferase SRC1, and mediator complex in leptin-mediated regulation of CYCLIN D1 promoter. Importantly, silencing of SRC1 and Med1 abolished the leptin induced increase in CYCLIN D1 expression and MCF7 cell proliferation. Intriguingly, recruitment of both SRC1 and Med1 was dependent on phosphorylated Stat3 as AG490 treatment inhibited leptin-induced recruitment of these coactivators to CYCLIN D1 promoter. Our data suggest that CYCLIN D1 may be a target gene for leptin mediated growth stimulation of breast cancer cells and molecular mechanisms involve activated Stat3-mediated recruitment of distinct coactivator complexes.

  6. Resistin and interleukin-6 exhibit racially-disparate expression in breast cancer patients, display molecular association and promote growth and aggressiveness of tumor cells through STAT3 activation.

    Science.gov (United States)

    Deshmukh, Sachin K; Srivastava, Sanjeev K; Bhardwaj, Arun; Singh, Ajay P; Tyagi, Nikhil; Marimuthu, Saravanakumar; Dyess, Donna L; Dal Zotto, Valeria; Carter, James E; Singh, Seema

    2015-05-10

    African-American (AA) women with breast cancer (BC) are diagnosed with more aggressive disease, have higher risk of recurrence and poorer prognosis as compared to Caucasian American (CA) women. Therefore, it is imperative to define the factors associated with such disparities to reduce the unequal burden of cancer. Emerging data suggest that inherent differences exist in the tumor microenvironment of AA and CA BC patients, however, its molecular bases and functional impact have remained poorly understood. Here, we conducted cytokine profiling in serum samples from AA and CA BC patients and identified resistin and IL-6 to be the most differentially-expressed cytokines with relative greater expression in AA patients. Resistin and IL-6 exhibited positive correlation in serum levels and treatment of BC cells with resistin led to enhanced production of IL-6. Moreover, resistin also enhanced the expression and phosphorylation of STAT3, and treatment of BC cells with IL-6-neutralizing antibody prior to resistin stimulation abolished STAT3 phosphorylation. In addition, resistin promoted growth and aggressiveness of BC cells, and these effects were mediated through STAT3 activation. Together, these findings suggest a crucial role of resistin, IL-6 and STAT3 in BC racial disparity.

  7. Entinostat up-regulates the CAMP gene encoding LL-37 via activation of STAT3 and HIF-1α transcription factors.

    Science.gov (United States)

    Miraglia, Erica; Nylén, Frank; Johansson, Katarina; Arnér, Elias; Cebula, Marcus; Farmand, Susan; Ottosson, Håkan; Strömberg, Roger; Gudmundsson, Gudmundur H; Agerberth, Birgitta; Bergman, Peter

    2016-01-01

    Bacterial resistance against classical antibiotics is a growing problem and the development of new antibiotics is limited. Thus, novel alternatives to antibiotics are warranted. Antimicrobial peptides (AMPs) are effector molecules of innate immunity that can be induced by several compounds, including vitamin D and phenyl-butyrate (PBA). Utilizing a luciferase based assay, we recently discovered that the histone deacetylase inhibitor Entinostat is a potent inducer of the CAMP gene encoding the human cathelicidin LL-37. Here we investigate a mechanism for the induction and also find that Entinostat up-regulates human β-defensin 1. Analysis of the CAMP promoter sequence revealed binding sites for the transcription factors STAT3 and HIF-1α. By using short hairpin RNA and selective inhibitors, we found that both transcription factors are involved in Entinostat-induced expression of LL-37. However, only HIF-1α was found to be recruited to the CAMP promoter, suggesting that Entinostat activates STAT3, which promotes transcription of CAMP by increasing the expression of HIF-1α. Finally, we provide in vivo relevance to our findings by showing that Entinostat-elicited LL-37 expression was impaired in macrophages from a patient with a STAT3-mutation. Combined, our findings support a role for STAT3 and HIF-1α in the regulation of LL-37 expression. PMID:27633343

  8. The role of STAT3 in autophagy.

    Science.gov (United States)

    You, Liangkun; Wang, Zhanggui; Li, Hongsen; Shou, Jiawei; Jing, Zhao; Xie, Jiansheng; Sui, Xinbing; Pan, Hongming; Han, Weidong

    2015-01-01

    Autophagy is an evolutionarily conserved process in eukaryotes that eliminates harmful components and maintains cellular homeostasis in response to a series of extracellular insults. However, these insults may trigger the downstream signaling of another prominent stress responsive pathway, the STAT3 signaling pathway, which has been implicated in multiple aspects of the autophagic process. Recent reports further indicate that different subcellular localization patterns of STAT3 affect autophagy in various ways. For example, nuclear STAT3 fine-tunes autophagy via the transcriptional regulation of several autophagy-related genes such as BCL2 family members, BECN1, PIK3C3, CTSB, CTSL, PIK3R1, HIF1A, BNIP3, and microRNAs with targets of autophagy modulators. Cytoplasmic STAT3 constitutively inhibits autophagy by sequestering EIF2AK2 as well as by interacting with other autophagy-related signaling molecules such as FOXO1 and FOXO3. Additionally, the mitochondrial translocation of STAT3 suppresses autophagy induced by oxidative stress and may effectively preserve mitochondria from being degraded by mitophagy. Understanding the role of STAT3 signaling in the regulation of autophagy may provide insight into the classic autophagy model and also into cancer therapy, especially for the emerging targeted therapy, because a series of targeted agents execute antitumor activities via blocking STAT3 signaling, which inevitably affects the autophagy pathway. Here, we review several of the representative studies and the current understanding in this particular field.

  9. NTRK2 activation cooperates with PTEN deficiency in T-ALL through activation of both the PI3K–AKT and JAK–STAT3 pathways

    Science.gov (United States)

    Yuzugullu, Haluk; Von, Thanh; Thorpe, Lauren M; Walker, Sarah R; Roberts, Thomas M; Frank, David A; Zhao, Jean J

    2016-01-01

    Loss of PTEN, a negative regulator of the phosphoinositide 3-kinase signaling pathway, is a frequent event in T-cell acute lymphoblastic leukemia, suggesting the importance of phosphoinositide 3-kinase activity in this disease. Indeed, hyperactivation of the phosphoinositide 3-kinase pathway is associated with the disease aggressiveness, poor prognosis and resistance to current therapies. To identify a molecular pathway capable of cooperating with PTEN deficiency to drive oncogenic transformation of leukocytes, we performed an unbiased transformation screen with a library of tyrosine kinases. We found that activation of NTRK2 is able to confer a full growth phenotype of Ba/F3 cells in an IL3-independent manner in the PTEN-null setting. NTRK2 activation cooperates with PTEN deficiency through engaging both phosphoinositide3-kinase/AKT and JAK/STAT3 pathway activation in leukocytes. Notably, pharmacological inhibition demonstrated that p110α and p110δ are the major isoforms mediating the phosphoinositide 3-kinase/AKT signaling driven by NTRK2 activation in PTEN-deficient leukemia cells. Furthermore, combined inhibition of phosphoinositide 3-kinase and STAT3 significantly suppressed proliferation of PTEN-mutant T-cell acute lymphoblastic leukemia both in culture and in mouse xenografts. Together, our data suggest that a unique conjunction of PTEN deficiency and NTRK2 activation in T-cell acute lymphoblastic leukemia, and combined pharmacologic inhibition of phosphoinositide 3-kinase and STAT3 signaling may serve as an effective and durable therapeutic strategy for T-cell acute lymphoblastic leukemia. PMID:27672444

  10. MEK kinase 1 is essential for Bcr-Abl-induced STAT3 and self-renewal activity in embryonic stem cells.

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    Nakamura, Yukinori; Yujiri, Toshiaki; Nawata, Ryouhei; Tagami, Kozo; Tanizawa, Yukio

    2005-11-17

    BCR-ABL oncogene, the molecular hallmark of chronic myelogenous leukemia, arises in a primitive hematopoietic stem cell that has the capacity for both differentiation and self-renewal. Its product, Bcr-Abl protein, has been shown to activate signal transducers and activators of transcription 3 (STAT3) and to promote self-renewal in embryonic stem (ES) cells, even in the absence of leukemia inhibitory factor (LIF). MEK kinase 1 (MEKK1) is a 196-kDa mitogen-activated protein kinase (MAPK) kinase kinase involved in Bcr-Abl signal transduction. To investigate the role of MEKK1 in Bcr-Abl-induced transformation of stem cells, p210 Bcr-Abl was stably transfected into wild-type (WT(p210)) and MEKK1-/- (MEKK1-/-(p210)) ES cells. Bcr-Abl enhanced MEKK1 expression in ES transfectants, as it does in other Bcr-Abl-transformed cells. In the absence of LIF, WT(p210) cells showed constitutive STAT3 activation and formed rounded, compact colonies having strong alkaline phosphatase activity, a characteristic phenotype of undifferentiated ES cells. MEKK1-/-(p210) cells, by contrast, showed less STAT3 activity than WT(p210) cells and formed large, flattened colonies having weak alkaline phosphatase activity, a phenotype of differentiated ES cells. These results indicate that MEKK1 plays a key role in Bcr-Abl-induced STAT3 activation and in ES cells' capacity for LIF-independent self-renewal, and may thus be involved in Bcr-Abl-mediated leukemogenesis in stem cells. PMID:16044153

  11. Stat3 mediates expression of autotaxin in breast cancer.

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    Janeen Azare

    Full Text Available We determined that signal transducer and activator of transcription 3 (Stat3 is tyrosine phosphorylated in 37% of primary breast tumors and 63% of paired metastatic axillary lymph nodes. Examination of the distribution of tyrosine phosphorylated (pStat3 in primary tumors revealed heterogenous expression within the tumor with the highest levels found in cells on the edge of tumors with relatively lower levels in the central portion of tumors. In order to determine Stat3 target genes that may be involved in migration and metastasis, we identified those genes that were differentially expressed in primary breast cancer samples as a function of pStat3 levels. In addition to known Stat3 transcriptional targets (Twist, Snail, Tenascin-C and IL-8, we identified ENPP2 as a novel Stat3 regulated gene, which encodes autotaxin (ATX, a secreted lysophospholipase which mediates mammary tumorigenesis and cancer cell migration. A positive correlation between nuclear pStat3 and ATX was determined by immunohistochemical analysis of primary breast cancer samples and matched axillary lymph nodes and in several breast cancer derived cell lines. Inhibition of pStat3 or reducing Stat3 expression led to a decrease in ATX levels and cell migration. An association between Stat3 and the ATX promoter, which contains a number of putative Stat3 binding sites, was determined by chromatin immunoprecipitation. These observations suggest that activated Stat3 may regulate the migration of breast cancer cells through the regulation of ATX.

  12. M-HIFU inhibits tumor growth, suppresses STAT3 activity and enhances tumor specific immunity in a transplant tumor model of prostate cancer.

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    Xiaoyi Huang

    Full Text Available OBJECTIVE: In this study, we explored the use of mechanical high intensity focused ultrasound (M-HIFU as a neo-adjuvant therapy prior to surgical resection of the primary tumor. We also investigated the role of signal transducer and activator of transcription 3 (STAT3 in M-HIFU elicited anti-tumor immune response using a transplant tumor model of prostate cancer. METHODS: RM-9, a mouse prostate cancer cell line with constitutively activated STAT3, was inoculated subcutaneously in C57BL/6J mice. The tumor-bearing mice (with a maximum tumor diameter of 5∼6 mm were treated by M-HIFU or sham exposure two days before surgical resection of the primary tumor. Following recovery, if no tumor recurrence was observed in 30 days, tumor rechallenge was performed. The growth of the rechallenged tumor, survival rate and anti-tumor immune response of the animal were evaluated. RESULTS: No tumor recurrence and distant metastasis were observed in both treatment groups employing M-HIFU + surgery and surgery alone. However, compared to surgery alone, M-HIFU combined with surgery were found to significantly inhibit the growth of rechallenged tumors, down-regulate intra-tumoral STAT3 activities, increase cytotoxic T cells in spleens and tumor draining lymph nodes (TDLNs, and improve the host survival. Furthermore, M-HIFU combined with surgery was found to significantly decrease the level of immunosuppression with concomitantly increased number and activities of dendritic cells, compared to surgery alone. CONCLUSION: Our results demonstrate that M-HIFU can inhibit STAT3 activities, and when combined synergistically with surgery, may provide a novel and promising strategy for the treatment of prostate cancers.

  13. Salinomycin Promotes Anoikis and Decreases the CD44+/CD24- Stem-Like Population via Inhibition of STAT3 Activation in MDA-MB-231 Cells.

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    Hyunsook An

    Full Text Available Triple-negative breast cancer (TNBC is an aggressive tumor subtype with an enriched CD44+/CD24- stem-like population. Salinomycin is an antibiotic that has been shown to target cancer stem cells (CSC; however, the mechanisms of action involved have not been well characterized. The objective of the present study was to investigate the effect of salinomycin on cell death, migration, and invasion, as well as CSC-like properties in MDA-MB-231 breast cancer cells. Salinomycin significantly induced anoikis-sensitivity, accompanied by caspase-3 and caspase-8 activation and PARP cleavage, during anchorage-independent growth. Salinomycin treatment also caused a marked suppression of cell migration and invasion with concomitant downregulation of MMP-9 and MMP-2 mRNA levels. Notably, salinomycin inhibited the formation of mammospheres and effectively reduced the CD44+/CD24- stem-like population during anchorage-independent growth. These observations were associated with the inhibition of STAT3 phosphorylation (Tyr705. Furthermore, interleukin-6 (IL-6-induced STAT3 activation was strongly suppressed by salinomycin challenge. These findings support the notion that salinomycin may be potentially efficacious for targeting breast cancer stem-like cells through the inhibition of STAT3 activation.

  14. Particulate Matter Facilitates C6 Glioma Cells Activation and the Release of Inflammatory Factors Through MAPK and JAK2/STAT3 Pathways.

    Science.gov (United States)

    Li, Ting; Zhao, Jianya; Ge, Jianbin; Yang, Jianbin; Song, Xinjian; Wang, Cheng; Mao, Jiamin; Zhang, Yan; Zou, Ye; Liu, Yanmei; Chen, Gang

    2016-08-01

    It has been widely accepted that astrocytes, play a role in regulating almost every physiological system. In the present study, we investigated the role of particulate matter (PM) in regulating activation of astrocytes. The glial cell strain C6 was cloned from a rat glioma which was induced by N-nitrosomethylurea. The C6 cells were plated at a density of 5 × 10(6) cells/10 cm diameter dish and incubated with different concentrations (0, 12, 25, 50, 100, 200, and 400 μg/mL) of PM for 24 h and different time (0, 1, 3, 6, 8,12, and 24 h) with 100 μg/mL at 37 °C. The study revealed that PM stimulated the expression of inducible nitric oxide synthase (iNOS) as well as the production of IL-1β in a dose- and time-dependent manner. Furthermore, activation of JAK2/STAT3 and p38/JNK/ERK MAPKs was found in astrocytes following PM treatment. Blockage of JAK and p38/JNK/ERK MAPKs with their specific inhibitors, AG490, SB202190, SP600125 and U0126 significantly reduced PM-induced iNOS expression and IL-1β production. In addition, it was demonstrated that inhibition of p38, JNK and JAK prevented STAT3 tyrosine phosphorylation induced by PM, while blocking ERK did not. MAPKs (p38 and JNK) could regulate tyrosine STAT3 phosphorylation, which suggested that the JAK2/STAT3 pathway might be the downstream of p38/JNK MAPK pathways. PMID:27068033

  15. Prognostic significance of STAT3 and phosphorylated STAT3 in human soft tissue tumors - a clinicopathological analysis

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    Nair Asha S

    2011-05-01

    Full Text Available Abstract Background Signal transducer and activator of transcription 3 (STAT3 is a key signaling molecule and a central cytoplasmic transcription factor, implicated in the regulation of growth. Its aberrant activation has been demonstrated to correlate with many types of human malignancy. However, whether constitutive STAT3 signaling plays a key role in the survival and growth of soft-tissue tumors is still unclear and hence needs to be elucidated further. In our study we examined the expression levels of STAT3 and pSTAT3 in different grades of soft tissue tumors and correlated with its clinicopathological characteristics. Methods Expression levels of STAT3 and pSTAT3 in soft tissue tumors were studied using Immunohistochemistry, Western blotting and Reverse transcriptase- PCR and correlated with its clinicopathological characteristics using Chi squared or Fisher's exact test and by logistic regression analysis. Statistical analysis was done using Intercooled Stata software (Intercooled Stata 8.2 version. Results Of the 82 soft tissue tumor samples, fifty four (65.8% showed immunoreactivity for STAT3 and twenty eight (34.1% for pSTAT3. Expression of STAT3 and pSTAT3 was significantly associated with tumor grade (P Conclusion These findings suggest that constitutive activation of STAT3 is an important factor related to carcinogenesis of human soft tissue tumors and is significantly associated with its clinicopathological parameters which may possibly have potential diagnostic implications.

  16. Anti-fibrotic actions of interleukin-10 against hypertrophic scarring by activation of PI3K/AKT and STAT3 signaling pathways in scar-forming fibroblasts.

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    Jihong Shi

    Full Text Available BACKGROUND: The hypertrophic scar (HS is a serious fibrotic skin condition and a major clinical problem. Interleukin-10 (IL-10 has been identified as a prospective scar-improving compound based on preclinical trials. Our previous work showed that IL-10 has anti-fibrotic effects in transforming growth factor (TGF-β1-stimulated fibroblasts, as well as potential therapeutic benefits for the prevention and reduction of scar formation. However, relatively little is known about the mechanisms underlying IL-10-mediated anti-fibrotic and scar-improvement actions. OBJECTIVE: To explore the expression of the IL-10 receptor in human HS tissue and primary HS fibroblasts (HSFs, and the molecular mechanisms contributing to the anti-fibrotic and scar-improvement capabilities of IL-10. METHODS: Expression of the IL-10 receptor was assessed in HS tissue and HSFs by immunohistochemistry, immunofluorescence microscopy, and polymerase chain reaction analysis. Primary HSFs were treated with IL-10, a specific phosphatidylinositol 3 kinase (PI3K inhibitor (LY294002 or a function-blocking antibody against the IL-10 receptor (IL-10RB. Next, Western blot analysis was used to evaluate changes in the phosphorylation status of AKT and signal transducers and activators of transcription (STAT 3, as well as the expression levels of fibrosis-related proteins. RESULTS: HS tissue and primary HSFs were characterized by expression of the IL-10 receptor and by high expression of fibrotic markers relative to normal controls. Primary HSFs expressed the IL-10 receptor, while IL-10 induced AKT and STAT3 phosphorylation in these cells. In addition, LY294002 blocked AKT and STAT phosphorylation, and also up-regulated expression levels of type I and type III collagen (Col 1 and Col 3 and alpha-smooth muscle actin (α-SMA in IL-10-treated cells. Similarly, IL-10RB reduced STAT3/AKT phosphorylation and blocked the IL-10-mediated mitigation of fibrosis in HSFs. CONCLUSION: IL-10 apparently

  17. Role of STAT3 in Cancer Metastasis and Translational Advances

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    Mohammad Zahid Kamran

    2013-01-01

    Full Text Available Signal transducer and activator of transcription 3 (STAT3 is a latent cytoplasmic transcription factor, originally discovered as a transducer of signal from cell surface receptors to the nucleus. It is activated by tyrosine phosphorylation at position 705 leading to its dimerization, nuclear translocation, DNA binding, and activation of gene transcription. Under normal physiological conditions, STAT3 activation is tightly regulated. However, compelling evidence suggests that STAT3 is constitutively activated in many cancers and plays a pivotal role in tumor growth and metastasis. It regulates cellular proliferation, invasion, migration, and angiogenesis that are critical for cancer metastasis. In this paper, we first describe the mechanism of STAT3 regulation followed by how STAT3 is involved in cancer metastasis, then we summarize the various small molecule inhibitors that inhibit STAT3 signaling.

  18. Role of STAT3 in Cancer Metastasis and Translational Advances

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    Patil, Prachi; Gude, Rajiv P.

    2013-01-01

    Signal transducer and activator of transcription 3 (STAT3) is a latent cytoplasmic transcription factor, originally discovered as a transducer of signal from cell surface receptors to the nucleus. It is activated by tyrosine phosphorylation at position 705 leading to its dimerization, nuclear translocation, DNA binding, and activation of gene transcription. Under normal physiological conditions, STAT3 activation is tightly regulated. However, compelling evidence suggests that STAT3 is constitutively activated in many cancers and plays a pivotal role in tumor growth and metastasis. It regulates cellular proliferation, invasion, migration, and angiogenesis that are critical for cancer metastasis. In this paper, we first describe the mechanism of STAT3 regulation followed by how STAT3 is involved in cancer metastasis, then we summarize the various small molecule inhibitors that inhibit STAT3 signaling. PMID:24199193

  19. Toxoplasma gondii Rhoptry Kinase ROP16 Activates STAT3 and STAT6 Resulting in Cytokine Inhibition and Arginase-1-Dependent Growth Control

    OpenAIRE

    Butcher, Barbara A.; Fox, Barbara A.; Rommereim, Leah M.; Sung Guk Kim; Maurer, Kirk J.; Felix Yarovinsky; Herbert, De'Broski R.; Bzik, David J.; Eric Y Denkers

    2011-01-01

    The ROP16 kinase of Toxoplasma gondii is injected into the host cell cytosol where it activates signal transducer and activator of transcription (STAT)-3 and STAT6. Here, we generated a ROP16 deletion mutant on a Type I parasite strain background, as well as a control complementation mutant with restored ROP16 expression. We investigated the biological role of the ROP16 molecule during T. gondii infection. Infection of mouse bone marrow-derived macrophages with rop16-deleted (ΔROP16) parasite...

  20. Role of STAT3 in inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    Ken Sugimoto

    2008-01-01

    Signal transducers and activators of transcription 3(STAT3)play an important role in various autoimmune disorders including inflammatory bowel disease(IBD).Recent studies have revealed that STAT3 activation plays distinctly difierent roles between innate immune responses and acquired immune responses in colitis.STAT3-mediated activation of acquired immune re-sponses plays a pathogenic role in colitis by enhancing the survival of pathogenic T cells.In contrast,STAT3-mediated activation of innate responses contributes to the suppression of colitis.This review will summarize the current understanding of the roles of STAT3 in IBD and the potential of targeting STAT3 for the treatment of BD,emphasizing recent observations.(C)2008 The WJG Press.All rights reserved.

  1. Stat3 isoforms, alpha and beta, demonstrate distinct intracellular dynamics with prolonged nuclear retention of Stat3beta mapping to its unique C-terminal end.

    Science.gov (United States)

    Huang, Ying; Qiu, Jihui; Dong, Shuo; Redell, Michele S; Poli, Valeria; Mancini, Michael A; Tweardy, David J

    2007-11-30

    Two isoforms of Stat3 (signal transducer and activator of transcription 3) are expressed in cells, alpha (p92) and beta (p83), both derived from a single gene by alternative mRNA splicing. The 55-residue C-terminal transactivation domain of Stat3alpha is deleted in Stat3beta and replaced by seven unique C-terminal residues (CT7) whose function remains uncertain. We subcloned the open reading frames of Stat3alpha and Stat3beta into the C terminus of green fluorescent protein (GFP). Fluorescent microscopic analysis of HEK293T cells transiently transfected with GFP-Stat3alpha or GFP-Stat3beta revealed similar kinetics and cytokine concentration dependence of nuclear accumulation; these findings were confirmed by high throughput microscope analysis of murine embryonic fibroblasts that lacked endogenous Stat3 but stably expressed either GFP-Stat3alpha or GFP-Stat3beta. However, although time to half-maximal cytoplasmic reaccumulation after cytokine withdrawal was 15 min for GFP-Stat3alpha, it was >180 min for GFP-Stat3beta. Furthermore, although the intranuclear mobility of GFP-Stat3alpha was rapid and increased with cytokine stimulation, the intranuclear mobility of GFP-Stat3beta in unstimulated cells was slower than that of GFP-Stat3alpha in unstimulated cells and was slowed further following cytokine stimulation. Deletion of the unique CT7 domain from Stat3beta eliminated prolonged nuclear retention but did not alter its intranuclear mobility. Thus, Stat3alpha and Stat3beta have distinct intracellular dynamics, with Stat3beta exhibiting prolonged nuclear retention and reduced intranuclear mobility especially following ligand stimulation. Prolonged nuclear retention, but not reduced intranuclear mobility, mapped to the CT7 domain of Stat3beta.

  2. Protein kinase CK2 inhibition down modulates the NF-κB and STAT3 survival pathways, enhances the cellular proteotoxic stress and synergistically boosts the cytotoxic effect of bortezomib on multiple myeloma and mantle cell lymphoma cells.

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    Sabrina Manni

    Full Text Available CK2 is a pivotal pro-survival protein kinase in multiple myeloma that may likely impinge on bortezomib-regulated cellular pathways. In the present study, we investigated CK2 expression in multiple myeloma and mantle cell lymphoma, two bortezomib-responsive B cell tumors, as well as its involvement in bortezomib-induced cytotoxicity and signaling cascades potentially mediating bortezomib resistance. In both tumors, CK2 expression correlated with that of its activated targets NF-κB and STAT3 transcription factors. Bortezomib-induced proliferation arrest and apoptosis were significantly amplified by the simultaneous inhibition of CK2 with two inhibitors (CX-4945 and K27 in multiple myeloma and mantle cell lymphoma cell lines, in a model of multiple myeloma bone marrow microenvironment and in cells isolated from patients. CK2 inhibition empowered bortezomib-triggered mitochondrial-dependent cell death. Phosphorylation of NF-κB p65 on Ser529 (a CK2 target site and rise of the levels of the endoplasmic reticulum stress kinase/endoribonuclease Ire1α were markedly reduced upon CK2 inhibition, as were STAT3 phospho Ser727 levels. On the contrary, CK2 inhibition increased phospho Ser51 eIF2α levels and enhanced the bortezomib-dependent accumulation of poly-ubiquitylated proteins and of the proteotoxic stress-associated chaperone Hsp70. Our data suggest that CK2 over expression in multiple myeloma and mantle cell lymphoma cells might sustain survival signaling cascades and can antagonize bortezomib-induced apoptosis at different levels. CK2 inhibitors could be useful in bortezomib-based combination therapies.

  3. Crif1 is a novel transcriptional coactivator of STAT3.

    Science.gov (United States)

    Kwon, Min-chul; Koo, Bon-Kyoung; Moon, Jin-Sook; Kim, Yoon-Young; Park, Ki Cheol; Kim, Nam-Shik; Kwon, Mi Yi; Kong, Myung-Phil; Yoon, Ki-Jun; Im, Sun-Kyoung; Ghim, Jaewang; Han, Yong-Mahn; Jang, Sung Key; Shong, Minho; Kong, Young-Yun

    2008-02-20

    Signal transducer and activator of transcription 3 (STAT3) is a transcriptional factor that performs a broad spectrum of biological functions in response to various stimuli. However, no specific coactivator that regulates the transcriptional activity of STAT3 has been identified. Here we report that CR6-interacting factor 1 (Crif1) is a specific transcriptional coactivator of STAT3, but not of STAT1 or STAT5a. Crif1 interacts with STAT3 and positively regulates its transcriptional activity. Crif1-/- embryos were lethal around embryonic day 6.5, and manifested developmental arrest accompanied with defective proliferation and massive apoptosis. The expression of STAT3 target genes was markedly reduced in a Crif1-/- blastocyst culture and in Oncostatin M-stimulated Crif1-deficient MEFs. Importantly, the key activities of constitutively active STAT3-C, such as transcription, DNA binding, and cellular transformation, were abolished in the Crif1-null MEFs, suggesting the essential role of Crif1 in the transcriptional activity of STAT3. Our results reveal that Crif1 is a novel and essential transcriptional coactivator of STAT3 that modulates its DNA binding ability, and shed light on the regulation of oncogenic STAT3.

  4. Hydrodynamic Gene Delivery of Interleukin-22 Protects the Mouse Liver from Concanavalin A-, Carbon Tetrachloride-, and Fas Ligand-Induced Injury via Activation of STAT3

    Institute of Scientific and Technical Information of China (English)

    HongnaPan; FengHong; SvetlanaRadaeva; BinGao

    2004-01-01

    Interleukin-22 (IL-22) is a recently identified T cell-derived cytokine whose biological significance remains obscure. Previously, we have shown that IL-22 plays a protective role in T cell-mediated hepatitis induced by Concanavalin A (Con A), acting as a survival factor for hepatocytes. In the present paper, we demonstrate that hydrodynamic gene delivery of IL-22 cDNA driven either by a liver-specific albumin promoter or a human cytomegalovirus (CMV) promoter results in IL-22 protein expression, STAT3 activation, and expression of several anti-apoptotic proteins, including Bcl-xL, Bcl-2, and Mcl-1 in the liver. Immunohistochemical analysis reveals that IL-22 protein expression is mainly detected in the cytoplasm of hepatocytes. Overexpression of IL-22 by hydrodynamic gene delivery significantly protects against liver injury, necrosis, and apoptosis induced by administration of Con A, carbon tetrachloride (CCl4), or the Fas agonist Jo-2 mAb. Western blot analyses show that overexpression of IL-22 significantly enhances activation of STAT3 and expression of Bcl-xL, Bcl-2, and Mcl-1 proteins in liver injury induced by Con A. In conclusion, hydrodynamic gene delivery of IL-22 protects against liver injury induced by a variety of toxins, suggesting the therapeutic potential of IL-22 in treating human liver disease. Cellular & Molecular Immunology. 2004;1(1):43-49.

  5. Hydrodynamic Gene Delivery of Interleukin-22 Protects the Mouse Liver from Concanavalin A-, Carbon Tetrachloride-, and Fas Ligand-Induced Injury via Activation of STAT3

    Institute of Scientific and Technical Information of China (English)

    Hongna Pan; Feng Hong; Svetlana Radaeva; Bin Gao

    2004-01-01

    Interleukin-22 (IL-22) is a recently identified T cell-derived cytokine whose biological significance remains obscure. Previously, we have shown that IL-22 plays a protective role in T cell-mediated hepatitis induced by Concanavalin A (Con A), acting as a survival factor for hepatocytes. In the present paper, we demonstrate that hydrodynamic gene delivery of IL-22 cDNA driven either by a liver-specific albumin promoter or a human cytomegalovirus (CMV) promoter results in IL-22 protein expression, STAT3 activation, and expression of several anti-apoptotic proteins, including Bcl-xL, Bcl-2, and Mcl-1 in the liver. Immunohistochemical analysis reveals that IL-22 protein expression is mainly detected in the cytoplasm of hepatocytes. Overexpression of IL-22 by hydrodynamic gene delivery significantly protects against liver injury, necrosis, and apoptosis induced by administration of Con A, carbon tetrachloride (CCl4), or the Fas agonist Jo-2 mAb. Western blot analyses show that overexpression of IL-22 significantly enhances activation of STAT3 and expression of Bcl-xL, Bcl-2,and Mcl-1 proteins in liver injury induced by Con A. In conclusion, hydrodynamic gene delivery of IL-22 protects against liver injury induced by a variety of toxins, suggesting the therapeutic potential of IL-22 in treating human liver disease. Cellular & Molecular Immunology. 2004;1(1):43-49.

  6. Non-CSCs nourish CSCs through interleukin-17E-mediated activation of NF-κB and JAK/STAT3 signaling in human hepatocellular carcinoma.

    Science.gov (United States)

    Luo, Yongli; Yang, Zhi; Su, Li; Shan, Juanjuan; Xu, Huailong; Xu, Yanmin; Liu, Limei; Zhu, Wei; Chen, Xuejiao; Liu, Chungang; Chen, Jun; Yao, Chao; Cheng, Feifei; Zhang, Chengcheng; Ma, Qinghua; Shen, Junjie; Qian, Cheng

    2016-06-01

    Within the cancer stem cell (CSC) niche, non-CSCs play an indispensable role in facilitating a microenvironment capable of maintaining CSC properties. Non-CSCs contribute to not only the structure and topology of the tumor microenvironment but also the maintenance of the dynamic state of CSCs. Interleukin-17E (IL-17E/IL-25) is important in allergic inflammation and protection against parasitic infection. Moreover, it has also been demonstrated that IL-17E takes part in different cancers recently. Here, for the first time we demonstrate that discrepant expression of IL-17E and the IL-17 receptor B (IL-17RB) exists in Nanog positive (Nanog(Pos)) CSCs and Nanog negative (Nanog(Neg)) non-CSCs in hepatocellular carcinoma (HCC). Moreover, we further demonstrate that IL-17E binding to IL-17RB activates NF-κB and JAK/Stat3 pathways to promote proliferation and sustain self-renewal of CSCs in HCC. Meanwhile, the beneficial effect of IL-17E on Nanog(Pos) CSCs could be blocked by specific inhibitors of JAK and NF-κB signaling. All the findings indicated that non-CSC-derived secreted IL-17E binds IL-17RB on CSCs to signal via JAK/Stat3 and NF-κB pathways to mediate crosstalk between CSCs and non-CSCs. Therefore, IL-17E/IL-17RB signaling represents a potential therapeutic target for treatment of HCC. PMID:27000993

  7. Nifuroxazide inhibits survival of multiple myeloma cells by directly inhibiting STAT3

    OpenAIRE

    Nelson, Erik A.; Walker, Sarah R.; Kepich, Alicia; Gashin, Laurie B.; Hideshima, Teru; Ikeda, Hiroshi; Chauhan, Dharminder; Anderson, Kenneth C.; Frank, David A.

    2008-01-01

    Constitutive activation of the transcription factor STAT3 contributes to the pathogenesis of many cancers, including multiple myeloma (MM). Since STAT3 is dispensable in most normal tissue, targeted inhibition of STAT3 is an attractive therapy for patients with these cancers. To identify STAT3 inhibitors, we developed a transcriptionally based assay and screened a library of compounds known to be safe in humans. We found the drug nifuroxazide to be an effective inhibitor of STAT3 function. Ni...

  8. Protective Function of STAT3 in CVB3-Induced Myocarditis

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    Diana Lindner

    2012-01-01

    Full Text Available The transcription factor signal transducer and activator of transcription 3 (STAT3 is an important mediator of the inflammatory process. We investigated the role of STAT3 in viral myocarditis and its possible role in the development to dilated cardiomyopathy. We used STAT3-deficent mice with a cardiomyocyte-restricted knockout and induced a viral myocarditis using Coxsackievirus B3 (CVB3 which induced a severe inflammation during the acute phase of the viral myocarditis. A complete virus clearance and an attenuated inflammation were examined in both groups WT and STAT3 KO mice 4 weeks after infection, but the cardiac function in STAT3 KO mice was significantly decreased in contrast to the infected WT mice. Interestingly, an increased expression of collagen I was detected in STAT3 KO mice compared to WT mice 4 weeks after CVB3 infection. Furthermore, the matrix degradation was reduced in STAT3 KO mice which might be an explanation for the observed matrix deposition. Consequently, we here demonstrate the protective function of STAT3 in CVB3-induced myocarditis. Since the cardiomyocyte-restricted knockout leads to an increased fibrosis, it can be assumed that STAT3 signalling in cardiomyocytes protects the heart against increased fibrosis through paracrine effects.

  9. Inhibition of constitutively activated Stat3 correlates with altered Bcl-2/Bax expression and induction of apoptosis in mycosis fungoides tumor cells

    DEFF Research Database (Denmark)

    Nielsen, M; Kaestel, C G; Eriksen, K W;

    1999-01-01

    in malignant transformation. In a previous study, we found constitutively tyrosine phosphorylated Stat3 in mycosis fungoides tumor cells. Here, we show that the Jak kinase inhibitor, Ag490, inhibits the constitutive binding of Stat3 to an oligonucleotide representing the Stat-binding sequence from the ICAM...

  10. A mix of S and ΔS variants of STAT3 enable survival of activated B-cell-like diffuse large B-cell lymphoma cells in culture

    Science.gov (United States)

    Zheng, M; Turton, K B; Zhu, F; Li, Y; Grindle, K M; Annis, D S; Lu, L; Drennan, A C; Tweardy, D J; Bharadwaj, U; Mosher, D F; Rui, L

    2016-01-01

    Activated B-cell-like diffuse large B-cell lymphoma (ABC DLBCL) is characterized by increased expression and activator of signal transducer and activator of transcription 3 (STAT3). ABC DLBCL cells require STAT3 for growth in culture. In ABC DLBCL cells, eosinophils and perhaps all cells, four variant STAT3 mRNAs (Sα, ΔSα, Sβ and ΔSβ) are present as a result of two alternative splicing events, one that results in the inclusion of a 55-residue C-terminal transactivation domain (α) or a truncated C-terminal domain with 7 unique residues (β) and a second that includes (S) or excludes (ΔS) the codon for Ser-701 in the linker between the SH2 and C-terminal domains. A substantial literature indicates that both α and β variants are required for optimal STAT3 function, but nothing is known about functions of ΔS variants. We used a knockdown/re-expression strategy to explore whether survival of ABC DLBCL cells requires that the four variants be in an appropriate ratio. No single variant rescued survival as well as STAT3Sα-C, Sα with activating mutations (A661C and N663C) in the SH2 domain. Better rescue was achieved when all four variants were re-expressed or Sα and ΔSα or Sβ and ΔSβ were re-expressed in pairs. Rescue correlated with expression of STAT3-sensitive genes NFKBIA and NFKBIZ. We consider a variety of explanations why a mix of S and ΔS variants of STAT3 should enable survival of ABC DLBCL cells. PMID:26727576

  11. STAT3: An Anti-Invasive Factor in Colorectal Cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Jong, Petrus Rudolf de [Department of Medicine, University of California, San Diego, 9500 Gilman Dr. MC 0663, La Jolla, CA 92093 (United States); Mo, Ji-Hun [Department of Otorhinolaryngology, Dankook University College of Medicine, 16-5 Anseo-dong, Cheonan, Chungcheongnam-do 330-715 (Korea, Republic of); Harris, Alexandra R.; Lee, Jongdae, E-mail: j142lee@ucsd.edu; Raz, Eyal [Department of Medicine, University of California, San Diego, 9500 Gilman Dr. MC 0663, La Jolla, CA 92093 (United States)

    2014-07-03

    Signal Transducer and Activator of Transcription 3 (STAT3) is activated in a majority of cancers, and promotes tumorigenesis and even metastasis through transcriptional activation of its target genes. Recently, we discovered that STAT3 suppresses epithelial-to-mesenchymal transition (EMT) and thus metastasis in a mouse model of colorectal cancer (CRC), while it did not affect the overall tumor burden. Furthermore, we found that STAT3 in intestinal epithelial cells (IEC) suppresses EMT by regulating stability of an EMT inducer, SNAI-1 (Snail-1). Here, STAT3 functions as an adaptor rather than a transcription factor in the post-translational modification of SNAI-1. In this review, we discuss the unexpected and contradictory role of STAT3 in metastasis of CRC and its clinical implications.

  12. STAT3: An Anti-Invasive Factor in Colorectal Cancer?

    Directory of Open Access Journals (Sweden)

    Petrus Rudolf de Jong

    2014-07-01

    Full Text Available Signal Transducer and Activator of Transcription 3 (STAT3 is activated in a majority of cancers, and promotes tumorigenesis and even metastasis through transcriptional activation of its target genes. Recently, we discovered that STAT3 suppresses epithelial-to-mesenchymal transition (EMT and thus metastasis in a mouse model of colorectal cancer (CRC, while it did not affect the overall tumor burden. Furthermore, we found that STAT3 in intestinal epithelial cells (IEC suppresses EMT by regulating stability of an EMT inducer, SNAI-1 (Snail-1. Here, STAT3 functions as an adaptor rather than a transcription factor in the post-translational modification of SNAI-1. In this review, we discuss the unexpected and contradictory role of STAT3 in metastasis of CRC and its clinical implications.

  13. Phosphorylated STAT3 physically interacts with NPM and transcriptionally enhances its expression in cancer.

    Science.gov (United States)

    Ren, Z; Aerts, J L; Pen, J J; Heirman, C; Breckpot, K; De Grève, J

    2015-03-26

    The signal transducer and activator of transcription 3 (STAT3) can be activated by the tyrosine kinase domain of the chimeric protein nucleophosmin/anaplastic lymphoma kinase (NPM/ALK), and has a pivotal role in mediating NPM/ALK-related malignant cell transformation. Although the role of STAT3 and wild-type NPM in oncogenesis has been extensively investigated, the relationship between both molecules in cancer remains poorly understood. In the present study, we first demonstrate that STAT3 phosphorylation at tyrosine 705 is accompanied by a concomitant increase in the expression level of NPM. Nuclear co-translocation of phosphorylated STAT3 with NPM can be triggered by interferon-alpha (IFN-α) stimulation of Jurkat cells and phosphorylated STAT3 co-localizes with NPM in cancer cells showing constitutive STAT3 activation. We further demonstrate that STAT3 phosphorylation can transcriptionally mediate NPM upregulation in IFN-α-stimulated Jurkat cells and is responsible for maintaining its expression in cancer cells showing constitutive STAT3 activation. Inhibition of STAT3 phosphorylation or knockdown of NPM expression abrogates their simultaneous transnuclear movements. Finally, we found evidence for a physical interaction between NPM and STAT3 in conditions of STAT3 activation. In conclusion, NPM is a downstream effector of the STAT3 signaling, and can facilitate the nuclear entry of phosphorylated STAT3. These observations might open novel opportunities for targeting the STAT3 pathway in cancer.

  14. Genetic Interactions of STAT3 and Anticancer Drug Development

    International Nuclear Information System (INIS)

    Signal transducer and activator of transcription 3 (STAT3) plays critical roles in tumorigenesis and malignant evolution and has been intensively studied as a therapeutic target for cancer. A number of STAT3 inhibitors have been evaluated for their antitumor activity in vitro and in vivo in experimental tumor models and several approved therapeutic agents have been reported to function as STAT3 inhibitors. Nevertheless, most STAT3 inhibitors have yet to be translated to clinical evaluation for cancer treatment, presumably because of pharmacokinetic, efficacy, and safety issues. In fact, a major cause of failure of anticancer drug development is lack of efficacy. Genetic interactions among various cancer-related pathways often provide redundant input from parallel and/or cooperative pathways that drives and maintains survival environments for cancer cells, leading to low efficacy of single-target agents. Exploiting genetic interactions of STAT3 with other cancer-related pathways may provide molecular insight into mechanisms of cancer resistance to pathway-targeted therapies and strategies for development of more effective anticancer agents and treatment regimens. This review focuses on functional regulation of STAT3 activity; possible interactions of the STAT3, RAS, epidermal growth factor receptor, and reduction-oxidation pathways; and molecular mechanisms that modulate therapeutic efficacies of STAT3 inhibitors

  15. Genetic Interactions of STAT3 and Anticancer Drug Development

    Directory of Open Access Journals (Sweden)

    Bingliang Fang

    2014-03-01

    Full Text Available Signal transducer and activator of transcription 3 (STAT3 plays critical roles in tumorigenesis and malignant evolution and has been intensively studied as a therapeutic target for cancer. A number of STAT3 inhibitors have been evaluated for their antitumor activity in vitro and in vivo in experimental tumor models and several approved therapeutic agents have been reported to function as STAT3 inhibitors. Nevertheless, most STAT3 inhibitors have yet to be translated to clinical evaluation for cancer treatment, presumably because of pharmacokinetic, efficacy, and safety issues. In fact, a major cause of failure of anticancer drug development is lack of efficacy. Genetic interactions among various cancer-related pathways often provide redundant input from parallel and/or cooperative pathways that drives and maintains survival environments for cancer cells, leading to low efficacy of single-target agents. Exploiting genetic interactions of STAT3 with other cancer-related pathways may provide molecular insight into mechanisms of cancer resistance to pathway-targeted therapies and strategies for development of more effective anticancer agents and treatment regimens. This review focuses on functional regulation of STAT3 activity; possible interactions of the STAT3, RAS, epidermal growth factor receptor, and reduction-oxidation pathways; and molecular mechanisms that modulate therapeutic efficacies of STAT3 inhibitors.

  16. Genetic Interactions of STAT3 and Anticancer Drug Development

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Bingliang [Department of Thoracic and Cardiovascular Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 (United States)

    2014-03-06

    Signal transducer and activator of transcription 3 (STAT3) plays critical roles in tumorigenesis and malignant evolution and has been intensively studied as a therapeutic target for cancer. A number of STAT3 inhibitors have been evaluated for their antitumor activity in vitro and in vivo in experimental tumor models and several approved therapeutic agents have been reported to function as STAT3 inhibitors. Nevertheless, most STAT3 inhibitors have yet to be translated to clinical evaluation for cancer treatment, presumably because of pharmacokinetic, efficacy, and safety issues. In fact, a major cause of failure of anticancer drug development is lack of efficacy. Genetic interactions among various cancer-related pathways often provide redundant input from parallel and/or cooperative pathways that drives and maintains survival environments for cancer cells, leading to low efficacy of single-target agents. Exploiting genetic interactions of STAT3 with other cancer-related pathways may provide molecular insight into mechanisms of cancer resistance to pathway-targeted therapies and strategies for development of more effective anticancer agents and treatment regimens. This review focuses on functional regulation of STAT3 activity; possible interactions of the STAT3, RAS, epidermal growth factor receptor, and reduction-oxidation pathways; and molecular mechanisms that modulate therapeutic efficacies of STAT3 inhibitors.

  17. Mutations in the signal transducer and activator of transcription 3 (STAT3) and diagnostic guidelines for the Hyper-IgE Syndrome

    Science.gov (United States)

    Woellner, Cristina; Gertz, E. Michael; Schäffer, Alejandro A.; Lagos, Macarena; Perro, Mario; Glocker, Erik-Oliver; Pietrogrande, Maria C.; Cossu, Fausto; Franco, José L.; Matamoros, Nuria; Pietrucha, Barbara; Heropolitańska-Pliszka, Edyta; Yeganeh, Mehdi; Moin, Mostafa; Español, Teresa; Ehl, Stephan; Gennery, Andrew R.; Abinun, Mario; Bręborowicz, Anna; Niehues, Tim; Kilic, Sara Sebnem; Junker, Anne; Turvey, Stuart E.; Plebani, Alessandro; Sánchez, Berta; Garty, Ben-Zion; Pignata, Claudio; Cancrini, Caterina; Litzman, Jiri; Sanal, Özden; Baumann, Ulrich; Bacchetta, Rosa; Hsu, Amy P.; Davis, Joie N.; Hammarström, Lennart; Davies, E. Graham; Eren, Efrem; Arkwright, Peter D.; Moilanen, Jukka S.; Viemann, Dorothee; Khan, Sujoy; Maródi, László; Cant, Andrew J.; Freeman, Alexandra F.; Puck, Jennifer M.; Holland, Steven M.; Grimbacher, Bodo

    2010-01-01

    Background The hyper-IgE syndrome (HIES) is a primary immunodeficiency characterized by infections of the lung and skin, elevated serum IgE, and involvement of the soft and tissues. Recently, HIES has been associated with heterozygous dominant-negative mutations in STAT3 and severe reductions of Th17 cells. Objective To determine whether there is a correlation between the genotype and phenotype of HIES patients and to establish diagnostic criteria to distinguish between STAT3 mutated and STAT3 wild-type patients. Methods We collected clinical data, determined Th17 cell numbers, and sequenced STAT3 100 patients with a strong clinical suspicion of HIES and serum IgE >1000 IU/mL. explored diagnostic criteria by using a machine-learning approach to identify which features best predict a STAT3 mutation. Results In 64 patients we identified 31 different STAT3 mutations, 18 of which are novel. These included mutations at splice sites and outside the previously implicated DNA-binding and SH2 domains. A combination of five clinical features predicted STAT3 mutations with 85% accuracy. Th17 cells were profoundly reduced in patients harboring STAT3 mutations, while 10 out of 13 patients without mutations had low (1000 IU/mL plus a weighted score of clinical features >30 based on recurrent pneumonia, newborn rash, pathologic bone fractures, characteristic face, and high palate. Probable: Above plus lack of Th17 cells or a family history for definitive HIES. Definitive: Above plus a dominant-negative heterozygous mutation in STAT3. PMID:20159255

  18. Plumbagin Promotes the Generation of Astrocytes from Rat Spinal Cord Neural Progenitors Via Activation of the Transcription Factor Stat3

    OpenAIRE

    Luo, Yongquan; Mughal, Mohamed; Ouyang, Xin; Jiang, Haiyang; Luo, Tae-Gen Son Weiming; Yu, Qian-sheng; Greig, Nigel H.; Mattson, Mark P

    2010-01-01

    Plumbagin (5-hydroxy-2-methyl-1,4 naphthoquinone) is a naturally occurring low molecular weight lipophilic phytochemical derived from roots of plants of the Plumbago genus. Plumbagin has been reported to have several clinically relevant biological activities in non-neural cells including antiatherosclerotic, anticoagulant, anticarcinogenic, antitumor and bactericidal effects. In a recent screen of a panel of botanical pesticides we identified plumbagin as having neuroprotective activity. In t...

  19. Suppression by Δ9-tetrahydrocannabinol of the primary immunoglobulin M response by human peripheral blood B cells is associated with impaired STAT3 activation

    International Nuclear Information System (INIS)

    This study was undertaken to gain insights into the mechanism for Δ9-tetrahydrocannabinol (Δ9-THC)-mediated suppression of primary immunoglobulin M (IgM) responses in humans. An in vitro activation model, which employs cell surface-expressed CD40 ligand (CD40L) and recombinant cytokines (interleukin (IL)-2, -6, and -10), was used to differentiate human peripheral blood (HPB) naïve B cells into IgM secreting cells. Pretreatment with Δ9-THC significantly decreased the number of IgM secreting cells as determined by ELISPOT. The attenuation of IgM secretion by Δ9-THC involved, at least in part, the impairment of plasma cell differentiation as evidenced by suppression of immunoglobulin joining chain (IgJ) mRNA expression. The analysis at each of two different stages critically involved in plasma cell differentiation indicates that Δ9-THC impaired both the primary activation stage and proliferation of B cells. Interestingly, Δ9-THC selectively suppressed the surface expression of CD80, but not other measured B-cell activation markers (CD69, CD86, and ICAM1). Furthermore, pretreatment with Δ9-THC was accompanied by a robust decrease of STAT3 phosphorylation, whereas the phosphorylation of the p65 NFκB subunit was not affected. Collectively, these data provide new insights into the mechanisms for impaired B cell function by Δ9-THC

  20. STAT3, p-STAT3 and HIF-1α are associated with vasculogenic mimicry and impact on survival in gastric adenocarcinoma

    OpenAIRE

    Song, Yan-Yan; SUN, LI-DAN; LIU, MIN-LI; LIU, ZHONG-LIANG; Chen, Fei; ZHANG, YING-ZHE; Zheng, Yan; Zhang, Jian-Ping

    2014-01-01

    Vasculogenic mimicry (VM) formation is important for invasion and metastasis of tumor cells in gastric adenocarcinoma (GAC). The present study aimed to investigate the association between signal transducer and activator of transcription-3 (STAT3), phosphor-STAT3 (p-STAT3), hypoxia-inducible factor-1α (HIF-1α) and VM formation in GAC, and discuss their clinical significance and correlation with the prognosis of patients with GAC. The expression levels of STAT3, p-STAT3, HIF-1α and VM were asse...

  1. Activation of mitochondrial STAT-3 and reduced mitochondria damage during hypothermia treatment for post-cardiac arrest myocardial dysfunction.

    Science.gov (United States)

    Huang, Chien-Hua; Tsai, Min-Shan; Chiang, Chih-Yen; Su, Yu-Jen; Wang, Tzung-Dau; Chang, Wei-Tien; Chen, Huei-Wen; Chen, Wen-Jone

    2015-11-01

    While therapeutic hypothermia improves the outcomes of individuals in cardiac arrest, the hemodynamic responses and mechanisms which underlie hypothermia-induced cardioprotection are not fully understood. Therefore, we investigated the mechanism by which induced hypothermia preserves cardiac function and protects against mitochondrial damage following cardiac arrest. Cardiac arrest was induced in adult male Wistar rats by asphyxiation for 8.5 min. Following resuscitation, the animals were randomly assigned to a hypothermia (32 °C) or normothermia (37 °C) group. Monitoring results showed that cardiac output at the fourth hour after resuscitation was significantly better in rats treated with hypothermia when compared to rats treated with normothermia (P mitochondrial permeability transition pores occurred less frequently in the hypothermic group. While complex I/III activity in the electron transport reaction was damaged after cardiac arrest and resuscitation, the degree of injury was ameliorated by hypothermia treatment (P mitochondrial integrity and electron transport activity.

  2. Low-level bisphenol A increases production of glial fibrillary acidic protein in differentiating astrocyte progenitor cells through excessive STAT3 and Smad1 activation

    International Nuclear Information System (INIS)

    The effects of bisphenol A (BPA) on the differentiation of serum-free mouse embryo (SFME) cells, the astrocyte progenitor cells in the central nervous system, were examined. SFME cells were exposed to 10 ng/ml leukemia inhibitory factor (LIF) and 10 ng/ml bone morphogenetic protein 2 (BMP2) to increase glial fibrillary acidic protein (GFAP) expression and induce cell differentiation. Various concentrations of BPA (0.1 pg/ml-1 μg/ml) were then added to determine their effects on the cell differentiation. SFME cells were effectively differentiated by LIF and BMP2 in completely serum-free cultures. Cell proliferation following cell differentiation was not significantly affected by low-level BPA. However, GFAP expression was significantly increased in SFME cells in the presence of 1-100 pg/ml BPA. These increases were due to excessive activation of signal transducer and activator of transcription 3 (STAT3) and mothers against decapentaplegic homolog 1 (Smad1) by the low-level BPA

  3. Apolipoprotein A-I inhibits LPS-induced atherosclerosis in ApoE-/-mice possibly via activated STAT3-mediated upregulation of tristetraprolin

    Institute of Scientific and Technical Information of China (English)

    Kai YIN; Shi-lin TANG; Xiao-hua YU; Guang-hui TU; Rong-fang HE; Jin-feng LI; Di XIE

    2013-01-01

    Aim:To investigate the effects of the major component of high-density lipoprotein apolipoprotein A-I (apoA-I) on the development of atherosclerosis in LPS-challenged ApoE-/-mice and the underlying mechanisms.Methods:Male ApoE-KO mice were daily injected with LPS (25 μg,sc) or PBS for 4 weeks.The LPS-challenged mice were intravenously injected with rAAV-apoA-I-GFP or rAAV-GFP.After the animals were killed,blood,livers and aortas were collected for biochemical and histological analyses.For ex vivo experiments,the abdominal cavity macrophages were harvested from each treatment group of mice,and cultured with autologous serum,then treated with LPS.Results:Chronic administration of LPS in ApoE-/-mice significantly increased the expression of inflammatory cytokines (TNF-α,IL-1β,IL-6,and MCP-1),increased infiltration of inflammatory cells,and enhanced the development of atherosclerosis.In LPS-challenged mice injected with rAAV-apoA-I-GFP,viral particles and human apoA-I were detected in the livers,total plasma human apoA-I levels were grammatically increased; HDL-cholesterol level was significantly increased,TG and TC were slightly increased.Furthermore,overexpression of apoA-l significantly suppressed the expression of proinflammatory cytokines,reduced the infiltration of inflammatory cells,and decreased the extent of atherosclerotic lesions.Moreover,overexpression of apoA-I significantly increased the expression of the cytokine mRNA-destabilizing protein tristetraprolin (TTP),and phosphorylation of JAK2 and STAT3 in aortas.In ex vivo mouse macrophages,the serum from mice overexpressing apoA-I significantly increased the expression of TTP,accompanied by accelerated decay of mRNAs of the inflammatory cytokines.Conclusion:ApoA-I potently suppresses LPS-induced atherosclerosis by inhibiting the inflammatory response possibly via activation of STAT3 and upregulation of TTP.

  4. Chronic Inhibition of STAT3/STAT5 in Treatment-Resistant Human Breast Cancer Cell Subtypes: Convergence on the ROS/SUMO Pathway and Its Effects on xCT Expression and System xc- Activity.

    Science.gov (United States)

    Linher-Melville, Katja; Nashed, Mina G; Ungard, Robert G; Haftchenary, Sina; Rosa, David A; Gunning, Patrick T; Singh, Gurmit

    2016-01-01

    Pharmacologically targeting activated STAT3 and/or STAT5 has been an active area of cancer research. The cystine/glutamate antiporter, system xc-, contributes to redox balance and export of intracellularly produced glutamate in response to up-regulated glutaminolysis in cancer cells. We have previously shown that blocking STAT3/5 using the small molecule inhibitor, SH-4-54, which targets the SH2 domains of both proteins, increases xCT expression, thereby increasing system xc- activity in human breast cancer cells. The current investigation demonstrates that chronic SH-4-54 administration, followed by clonal selection of treatment-resistant MDA-MB-231 and T47D breast cancer cells, elicits distinct subtype-dependent effects. xCT mRNA and protein levels, glutamate release, and cystine uptake are decreased relative to untreated passage-matched controls in triple-negative MDA-MB-231 cells, with the inverse occurring in estrogen-responsive T47D cells. This "ying-yang" effect is linked with a shifted balance between the phosphorylation status of STAT3 and STAT5, intracellular ROS levels, and STAT5 SUMOylation/de-SUMOylation. STAT5 emerged as a definitive negative regulator of xCT at the transcriptional level, while STAT3 activation is coupled with increased system xc- activity. We propose that careful classification of a patient's breast cancer subtype is central to effectively targeting STAT3/5 as a therapeutic means of treating breast cancer, particularly given that xCT is emerging as an important biomarker of aggressive cancers.

  5. Mitochondrial localized STAT3 is involved in NGF induced neurite outgrowth.

    Directory of Open Access Journals (Sweden)

    Lihan Zhou

    Full Text Available BACKGROUND: Signal transducer and activator of transcription 3 (STAT3 plays critical roles in neural development and is increasingly recognized as a major mediator of injury response in the nervous system. Cytokines and growth factors are known to phosphorylate STAT3 at tyrosine(705 with or without the concomitant phosphorylation at serine(727, resulting in the nuclear localization of STAT3 and subsequent transcriptional activation of genes. Recent evidence suggests that STAT3 may control cell function via alternative mechanisms independent of its transcriptional activity. Currently, the involvement of STAT3 mono-phosphorylated at residue serine(727 (P-Ser-STAT3 in neurite outgrowth and the underlying mechanism is largely unknown. PRINCIPAL FINDINGS: In this study, we investigated the role of nerve growth factor (NGF induced P-Ser-STAT3 in mediating neurite outgrowth. NGF induced the phosphorylation of residue serine(727 but not tyrosine(705 of STAT3 in PC12 and primary cortical neuronal cells. In PC12 cells, serine but not tyrosine dominant negative mutant of STAT3 was found to impair NGF induced neurite outgrowth. Unexpectedly, NGF induced P-Ser-STAT3 was localized to the mitochondria but not in the nucleus. Mitochondrial STAT3 was further found to be intimately involved in NGF induced neurite outgrowth and the production of reactive oxygen species (ROS. CONCLUSION: Taken together, the findings herein demonstrated a hitherto unrecognized novel transcription independent mechanism whereby the mitochondria localized P-Ser-STAT3 is involved in NGF induced neurite outgrowth.

  6. Differences in antiproliferative effect of STAT3 inhibition in HCC cells with versus without HBV expression

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Yun; Zhou, Lin; Xie, Haiyang; Wang, Weilin [Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Qingchun Road 79, Hangzhou, Zhejiang 310003 (China); Key Laboratory of Combined Multi-organ Transplantation of Ministry of Public Health, Qingchun Road 79, Hangzhou, Zhejiang 310003 (China); Zheng, Shusen, E-mail: shusenzheng@zju.edu.cn [Division of Hepatobiliary and Pancreatic Surgery, Department of Surgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Qingchun Road 79, Hangzhou, Zhejiang 310003 (China); Key Laboratory of Combined Multi-organ Transplantation of Ministry of Public Health, Qingchun Road 79, Hangzhou, Zhejiang 310003 (China)

    2015-06-05

    Chronic infection with hepatitis B virus (HBV) plays an important role in the etiology of hepatocellular carcinoma (HCC). Signal transducer and activator of transcription 3 (STAT3) inactivation could inhibit the tumor growth of HCC. In this study, differential antiproliferative effect of STAT3 inhibition was observed with HBV-related HCC cells being more resistant than non-HBV-related HCC cells. Resistance of HBV-related HCC cells to STAT3 inhibition was positively correlated to the expression of HBV. Enhanced ERK activation after STAT3 blockade was detected in HBV-related HCC cells but not in non-HBV-related HCC cells. Combined ERK and STAT3 inhibition eliminates the discrepancy between the two types of HCC cells. Moderate reduced HBV expression was found after STAT3 inhibition. These findings disclose a discrepancy in cellular response to STAT3 inhibition between non-HBV-related and HBV-related HCC cells and underscore the complexity of antiproliferative effect of STAT3 inactivation in HBV-related HCC cells. - Highlights: • HBV endows HCC cells with resistance to STAT3 inactivation on proliferation. • Abnormal ERK activation after STAT3 inhibition in HBV-related HCC cells. • Combined ERK and STAT3 inhibition eliminates the discrepancy. • STAT3 inhibition moderately reduces HBV expression.

  7. ENMD-1198, a novel tubulin-binding agent reduces HIF-1alpha and STAT3 activity in human hepatocellular carcinoma(HCC cells, and inhibits growth and vascularization in vivo

    Directory of Open Access Journals (Sweden)

    Schlitt Hans J

    2008-07-01

    Full Text Available Abstract Background Hepatocellular carcinoma (HCC represents a highly vascularized tumor entity and the process of angiogenesis is essential for the growth of HCC. Importantly, the pro-angiogenic transcription factors HIF-1α and STAT3 have been implicated in HCC progression, thus representing interesting targets for molecular targeted therapy. We hypothesized that therapeutic inhibition of HIF-1α could be achieved by using a novel tubulin-binding agent (ENMD-1198. ENMD-1198 is an analog of 2-methoxyestradiol (2ME2 with antiproliferative and antiangiogenic activity. Methods The human HCC cell lines HUH-7 and HepG2 were used for experiments. Effects of ENMD-1198 on constitutive and inducible (hypoxia, growth factors activation of signaling cascades, including HIF-1α and STAT3, were investigated by Western blotting. Changes in VEGF expression were determined by real-time PCR. Effects of ENMD-1198 on cancer cell migration and invasion were evaluated in in vitro-assays. The growth-inhibitory effects of ENMD-1198 (200 mg/kg/day were determined in a subcutaneous tumor model (HUH-7. Results ENMD-1198 inhibited the phosphorylation of MAPK/Erk, PI-3K/Akt and FAK. Moreover, activation of HIF-1α and STAT3 was dramatically reduced by ENMD-1198, which resulted in lower VEGF mRNA expression (P In vivo, treatment with ENMD-1198 led to a significant reduction in tumor growth, tumor vascularization, and numbers of proliferating tumor cells (P Conclusion The novel microtubule destabilizing agent ENMD-1198 is suitable for inhibiting HIF-1α and STAT3 in human HCC cells and leads to reduced tumor growth and vascularization in vivo. Hence, inhibition of HIF-1α and STAT3 could prove valuable for therapy of hepatocellular carcinoma.

  8. Integrative proteomics and transcriptomics revealed that activation of the IL-6R/JAK2/STAT3/MMP9 signaling pathway is correlated with invasion of pituitary null cell adenomas.

    Science.gov (United States)

    Feng, Jie; Yu, Sheng-Yuan; Li, Chu-Zhong; Li, Zhen-Ye; Zhang, Ya-Zhuo

    2016-11-15

    Non-functioning pituitary adenomas (NFPAs) are a highly heterogeneous group, but few studies have explored the invasion mechanism of specific subtypes of NFPAs. The objective of this study was to investigate the differential molecular expression patterns and the critical biological signaling pathways involved in the invasion of pituitary null cell adenomas (PNCAs) through integrative proteomics and transcriptomics. A total of 1160 genes and 283 proteins were found to be differentially expressed in invasive and non-invasive PNCAs. The differentially expressed molecules related to invasion were enriched in 15 canonical signaling pathways, 15 clusters of diseases or biological functions and 5 upstream molecules. Among them, the majority of the differentially expressed molecules were found to be involved in transport of molecule, migration of cells and cell movement. Notably, IL-6 was a significantly activated upstream regulator, and the IL6R/JAK2/STAT3 cascade was found to play a critical role in acute phase response signaling, which was the most significant canonical signaling pathway. Furthermore, we validated the overexpression of IL-6R, JAK2, STAT3, p-STAT3 and MMP9 in invasive PNCAs. Our data suggest that overactivation of the IL-6R/JAK2/STAT3/MMP9 pathway is critical for the invasion of PNCAs. PMID:27465831

  9. Toxoplasma gondii rhoptry kinase ROP16 activates STAT3 and STAT6 resulting in cytokine inhibition and arginase-1-dependent growth control.

    Science.gov (United States)

    Butcher, Barbara A; Fox, Barbara A; Rommereim, Leah M; Kim, Sung Guk; Maurer, Kirk J; Yarovinsky, Felix; Herbert, De'Broski R; Bzik, David J; Denkers, Eric Y

    2011-09-01

    The ROP16 kinase of Toxoplasma gondii is injected into the host cell cytosol where it activates signal transducer and activator of transcription (STAT)-3 and STAT6. Here, we generated a ROP16 deletion mutant on a Type I parasite strain background, as well as a control complementation mutant with restored ROP16 expression. We investigated the biological role of the ROP16 molecule during T. gondii infection. Infection of mouse bone marrow-derived macrophages with rop16-deleted (ΔROP16) parasites resulted in increased amounts of IL-12p40 production relative to the ROP16-positive RH parental strain. High level IL-12p40 production in ΔROP16 infection was dependent on the host cell adaptor molecule MyD88, but surprisingly was independent of any previously recognized T. gondii triggered pathway linking to MyD88 (TLR2, TLR4, TLR9, TLR11, IL-1ß and IL-18). In addition, ROP16 was found to mediate the suppressive effects of Toxoplasma on LPS-induced cytokine synthesis in macrophages and on IFN-γ-induced nitric oxide production by astrocytes and microglial cells. Furthermore, ROP16 triggered synthesis of host cell arginase-1 in a STAT6-dependent manner. In fibroblasts and macrophages, failure to induce arginase-1 by ΔROP16 tachyzoites resulted in resistance to starvation conditions of limiting arginine, an essential amino acid for replication and virulence of this parasite. ΔROP16 tachyzoites that failed to induce host cell arginase-1 displayed increased replication and dissemination during in vivo infection. We conclude that encounter between Toxoplasma ROP16 and the host cell STAT signaling cascade has pleiotropic downstream effects that act in multiple and complex ways to direct the course of infection. PMID:21931552

  10. Toxoplasma gondii rhoptry kinase ROP16 activates STAT3 and STAT6 resulting in cytokine inhibition and arginase-1-dependent growth control.

    Directory of Open Access Journals (Sweden)

    Barbara A Butcher

    2011-09-01

    Full Text Available The ROP16 kinase of Toxoplasma gondii is injected into the host cell cytosol where it activates signal transducer and activator of transcription (STAT-3 and STAT6. Here, we generated a ROP16 deletion mutant on a Type I parasite strain background, as well as a control complementation mutant with restored ROP16 expression. We investigated the biological role of the ROP16 molecule during T. gondii infection. Infection of mouse bone marrow-derived macrophages with rop16-deleted (ΔROP16 parasites resulted in increased amounts of IL-12p40 production relative to the ROP16-positive RH parental strain. High level IL-12p40 production in ΔROP16 infection was dependent on the host cell adaptor molecule MyD88, but surprisingly was independent of any previously recognized T. gondii triggered pathway linking to MyD88 (TLR2, TLR4, TLR9, TLR11, IL-1ß and IL-18. In addition, ROP16 was found to mediate the suppressive effects of Toxoplasma on LPS-induced cytokine synthesis in macrophages and on IFN-γ-induced nitric oxide production by astrocytes and microglial cells. Furthermore, ROP16 triggered synthesis of host cell arginase-1 in a STAT6-dependent manner. In fibroblasts and macrophages, failure to induce arginase-1 by ΔROP16 tachyzoites resulted in resistance to starvation conditions of limiting arginine, an essential amino acid for replication and virulence of this parasite. ΔROP16 tachyzoites that failed to induce host cell arginase-1 displayed increased replication and dissemination during in vivo infection. We conclude that encounter between Toxoplasma ROP16 and the host cell STAT signaling cascade has pleiotropic downstream effects that act in multiple and complex ways to direct the course of infection.

  11. STAT3 as a target for inducing apoptosis in solid and hematological tumors

    Institute of Scientific and Technical Information of China (English)

    Khandaker Al Zaid Siddiquee; James Turkson

    2008-01-01

    Studies in the past few years have provided compelling evidence for the critical role of aberrant Signal Transducer and Activator of Transcription 3 (STAT3) in malignant transformation and tumorigenesis. Thus, it is now generally accepted that STAT3 is one of the critical players in human cancer formation and represents a valid target for novel anticancer drug design. This review focuses on aberrant STAT3 and its role in promoting tumor cell survival and supporting the malignant phenotype. A brief evaluation of the current strategies targeting STAT3 for the development of novel anticancer agents against human tumors harboring constitutively active STAT3 will also be presented.

  12. Cross-talk between KLF4 and STAT3 regulates axon regeneration

    Science.gov (United States)

    Qin, Song; Zou, Yuhua; Zhang, Chun-Li

    2013-10-01

    Cytokine-induced activation of signal transducer and activator of transcription 3 (STAT3) promotes the regrowth of damaged axons in the adult central nervous system (CNS). Here we show that KLF4 physically interacts with STAT3 upon cytokine-induced phosphorylation of tyrosine 705 (Y705) on STAT3. This interaction suppresses STAT3-dependent gene expression by blocking its DNA-binding activity. The deletion of KLF4 in vivo induces axon regeneration of adult retinal ganglion cells (RGCs) via Janus kinase (JAK)-STAT3 signalling. This regeneration can be greatly enhanced by exogenous cytokine treatment, or removal of an endogenous JAK-STAT3 pathway inhibitor called suppressor of cytokine signalling 3 (SOCS3). These findings reveal an unexpected cross-talk between KLF4 and activated STAT3 in the regulation of axon regeneration that might have therapeutic implications in promoting repair of injured adult CNS.

  13. Identification and characterization of cis elements in the STAT3 gene regulating STAT3 alpha and STAT3 beta messenger RNA splicing.

    Science.gov (United States)

    Shao, H; Quintero, A J; Tweardy, D J

    2001-12-15

    Signal transducer and activator of transcription 3 (STAT3) is an oncogene and a critical regulator of multiple cell-fate decisions, including myeloid cell differentiation. Two isoforms of STAT3 have been identified: alpha (p92) and beta (p83). These differ structurally in their C-terminal transactivation domains, resulting in distinct functional activities. The cis genetic elements that regulate the ratio of alpha to beta messenger RNA (mRNA) are unknown. In this study, cloning, sequencing, and splicing analysis of the human and murine STAT3 genes revealed a highly conserved 5' donor site for generation of both alpha and beta mRNA and distinct branch-point sequences, polypyrimidine tracts, and 3' acceptor sites (ASs) for each. The beta 3' AS was found to be located 50 nucleotides downstream of the alpha 3' AS in exon 23. Two additional cryptic 3' ASs (delta and epsilon) were also identified. Thus, we identified for the first time the cis regulatory sequences responsible for generation of STAT3 alpha and STAT3 beta mRNA.

  14. STAT3 inhibition induces apoptosis in cancer cells independent of STAT1 or STAT2

    Directory of Open Access Journals (Sweden)

    Beverly E Barton

    2013-02-01

    Full Text Available Signal transducers and activators of transcription (STATs were originally discovered as mediators of signal transduction. Persistent aberrant activation of STAT3 is part of the malignant phenotype of hormone-refractory prostate cancer and pancreatic cancer; this is thought to be mediated by homodimers of phosphorylated STAT3, which translocate to the nucleus.  One consequence of persistently-activated STAT3 in malignant cells is that they depend upon it for survival.   STAT3 is observed to heterodimerize with STAT1 and STAT2; however the contributions of STAT3:STAT1  and STAT3:STAT2 heterodimers to the survival of malignant cells have not been investigated in detail. Previously we reported that single-stranded oligonucleotides containing consensus STAT3 binding sequences (13410 and 13411 were more effective for inducing apoptosis in prostate cancer cells than antisense STAT3 oligonucleotides. Control oligonucleotides (scrambled sequences had no effect. STAT3-inhibiting oligonucleotide 13410, but not scrambled-sequence oligonucleotides, induced apoptosis in pancreatic cancer cells as well.  Here we report that 13410 and derivative olignucleotides induced apoptosis in STAT1-null and STAT2-null fibrosarcoma cell lines U3A and U6A, as well as in the parental fibrosarcoma cell line 2fTGH. The cell lines expressed constitutively-activated STAT3 and depended on its activity for survival.  Forty-eight hr after transfection of 13410 or related oligonucleotides, significant apoptosis was observed in 2fTGH, U3A and U6A cells. Scrambled-sequence oligonucleotides had no effect on survival.  These data indicate that neither STAT1 nor STAT2 play significant roles in the maintenance of these cells, and by extension that STAT3:STAT1 and STAT3:STAT2 heterodimers regulate a different set of genes from STAT3:STAT3 homodimers.   

  15. IGFBP2 potentiates nuclear EGFR-STAT3 signaling.

    Science.gov (United States)

    Chua, C Y; Liu, Y; Granberg, K J; Hu, L; Haapasalo, H; Annala, M J; Cogdell, D E; Verploegen, M; Moore, L M; Fuller, G N; Nykter, M; Cavenee, W K; Zhang, W

    2016-02-11

    Insulin-like growth factor binding protein 2 (IGFBP2) is a pleiotropic oncogenic protein that has both extracellular and intracellular functions. Despite a clear causal role in cancer development, the tumor-promoting mechanisms of IGFBP2 are poorly understood. The contributions of intracellular IGFBP2 to tumor development and progression are also unclear. Here we present evidence that both exogenous IGFBP2 treatment and cellular IGFBP2 overexpression lead to aberrant activation of epidermal growth factor receptor (EGFR), which subsequently activates signal transducer and activator of transcription factor 3 (STAT3) signaling. Furthermore, we demonstrate that IGFBP2 augments the nuclear accumulation of EGFR to potentiate STAT3 transactivation activities, via activation of the nuclear EGFR signaling pathway. Nuclear IGFBP2 directly influences the invasive and migratory capacities of human glioblastoma cells, providing a direct link between intracellular (and particularly nuclear) IGFBP2 and cancer hallmarks. These activities are also consistent with the strong association between IGFBP2 and STAT3-activated genes derived from The Cancer Genome Atlas database for human glioma. A high level of all three proteins (IGFBP2, EGFR and STAT3) was strongly correlated with poorer survival in an independent patient data set. These results identify a novel tumor-promoting function for IGFBP2 of activating EGFR/STAT3 signaling and facilitating EGFR accumulation in the nucleus, thereby deregulating EGFR signaling by two distinct mechanisms. As targeting EGFR in glioma has been relatively unsuccessful, this study suggests that IGFBP2 may be a novel therapeutic target.

  16. Cannabinoid receptor CB1 regulates STAT3 activity and its expression dictates the responsiveness to SR141716 treatment in human glioma patients' cells.

    Science.gov (United States)

    Ciaglia, Elena; Torelli, Giovanni; Pisanti, Simona; Picardi, Paola; D'Alessandro, Alba; Laezza, Chiara; Malfitano, Anna Maria; Fiore, Donatella; Pagano Zottola, Antonio Christian; Proto, Maria Chiara; Catapano, Giuseppe; Gazzerro, Patrizia; Bifulco, Maurizio

    2015-06-20

    Herein we show that a majority of human brain tumor samples and cell lines over-expressed cannabinoid receptor CB1 as compared to normal human astrocytes (NHA), while uniformly expressed low levels of CB2. This finding prompted us to investigate the therapeutic exploitation of CB1 inactivation by SR141716 treatment, with regard to its direct and indirect cell-mediated effects against gliomas. Functional studies, using U251MG glioma cells and primary tumor cell lines derived from glioma patients expressing different levels of CB1, highlighted SR141716 efficacy in inducing apoptosis via G1 phase stasis and block of TGF-β1 secretion through a mechanism that involves STAT3 inhibition. According to the multivariate role of STAT3 in the immune escape too, interestingly SR141716 lead also to the functional and selective expression of MICA/B on the surface of responsive malignant glioma cells, but not on NHA. This makes SR141716 treated-glioma cells potent targets for allogeneic NK cell-mediated recognition through a NKG2D restricted mechanism, thus priming them for NK cell antitumor reactivity. These results indicate that CB1 and STAT3 participate in a new oncogenic network in the complex biology of glioma and their expression levels in patients dictate the efficacy of the CB1 antagonist SR141716 in multimodal glioma destruction.

  17. IGFBP2 potentiates nuclear EGFR-STAT3 signaling

    Science.gov (United States)

    Chua, Corrine Yingxuan; Liu, Yuexin; Granberg, Kirsi J.; Hu, Limei; Haapasalo, Hannu; Annala, Matti J.; Cogdell, David E.; Verploegen, Maartje; Moore, Lynette M.; Fuller, Gregory N.; Nykter, Matti; Cavenee, Webster K.; Zhang, Wei

    2015-01-01

    Insulin-like growth factor binding protein 2 (IGFBP2) is a pleiotropic oncogenic protein that has both extracellular and intracellular functions. Despite a clear causal role in cancer development, the tumor-promoting mechanisms of IGFBP2 are poorly understood. The contributions of intracellular IGFBP2 to tumor development and progression are also unclear. Here we present evidence that both exogenous IGFBP2 treatment and cellular IGFBP2 overexpression lead to aberrant activation of EGFR, which subsequently activates STAT3 signaling. Furthermore, we demonstrate that IGFBP2 augments the nuclear accumulation of EGFR to potentiate STAT3 transactivation activities, via activation of the nuclear EGFR signaling pathway. Nuclear IGFBP2 directly influences the invasive and migratory capacities of human glioblastoma cells, providing a direct link between intracellular (and particularly nuclear) IGFBP2 and cancer hallmarks. These activities are also consistent with the strong association between IGFBP2 and STAT3-activated genes derived from the TCGA database for human glioma. A high level of all 3 proteins (IGFBP2, EGFR and STAT3) was strongly correlated with poorer survival in an independent patient dataset. These results identify a novel tumor-promoting function for IGFBP2 of activating EGFR/STAT3 signaling and facilitating EGFR accumulation in the nucleus, thereby deregulating EGFR signaling by 2 distinct mechanisms. As targeting EGFR in glioma has been relatively unsuccessful, this study suggests that IGFBP2 may be a novel therapeutic target. PMID:25893308

  18. Suppression of autophagy augments the radiosensitizing effects of STAT3 inhibition on human glioma cells

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Xiaopeng; Du, Jie; Hua, Song; Zhang, Haowen; Gu, Cheng; Wang, Jie; Yang, Lei; Huang, Jianfeng; Yu, Jiahua, E-mail: yujiahua@suda.edu.cn; Liu, Fenju, E-mail: fangsh@suda.edu.cn

    2015-01-15

    Radiotherapy is an essential component of the standard therapy for newly diagnosed glioblastoma. To increase the radiosensitivity of glioma cells is a feasible solution to improve the therapeutic effects. It has been suggested that inhibition of signal transducer and activator of transcription 3 (STAT3) can radiosensitize glioma cells, probably via the activation of mitochondrial apoptotic pathway. In this study, human malignant glioma cells, U251 and A172, were treated with an STAT3 inhibitor, WP1066, or a short hairpin RNA plasmid targeting STAT3 to suppress the activation of STAT3 signaling. The radiosensitizing effects of STAT3 inhibition were confirmed in glioma cells. Intriguingly, combination of ionizing radiation exposure and STAT3 inhibition triggered a pronounced increase of autophagy flux. To explore the role of autophagy, glioma cells were treated with 3-methyladenine or siRNA for autophagy-related gene 5, and it was demonstrated that inhibition of autophagy further strengthened the radiosensitizing effects of STAT3 inhibition. Accordingly, more apoptotic cells were induced by the dual inhibition of autophagy and STAT3 signaling. In conclusion, our data revealed a protective role of autophagy in the radiosensitizing effects of STAT3 inhibition, and inhibition of both autophagy and STAT3 might be a potential therapeutic strategy to increase the radiosensitivity of glioma cells. - Highlights: • Inactivation of STAT3 signaling radiosensitizes malignant glioma cells. • STAT3 inhibition triggers a significant increase of autophagy flux induced by ionizing radiation in glioma cells. • Suppression of autophagy further strengthens the radiosensitizing effects of STAT3 inhibition in glioma cells. • Dual inhibition of autophagy and STAT3 induce massive apoptotic cells upon exposure to ionizing radiation.

  19. Loss of STAT3 in Lymphoma Relaxes NK Cell-Mediated Tumor Surveillance

    Directory of Open Access Journals (Sweden)

    Eva Maria Putz

    2014-01-01

    Full Text Available The transcription factors and proto-oncogenes STAT3 and STAT5 are highly activated in hematological malignancies and represent promising therapeutic targets. Whereas the importance of STAT5 as tumor promoter is beyond doubt, the role of STAT3 in hematological cancers is less well understood. Both, enforced as well as attenuated expression of STAT3 were reported in hematopoietic malignancies. Recent evidence implicates STAT3 as key player for tumor immune surveillance as it both mediates the production of and response to inflammatory cytokines. Here we investigated the effects of STAT3 deletion in a BCR/ABL-induced lymphoma model, which is tightly controlled by natural killer (NK cells in vivo. Upon STAT3 deletion tumor growth is significantly enhanced when compared to STAT3-expressing controls. The increased tumor size upon loss of STAT3 was accompanied by reduced NK cell infiltration and decreased levels of the cytokine IFN-γ and the chemokine RANTES. Upon transplantation into NK cell-deficient mice differences in lymphoma size were abolished indicating that STAT3 expression in the tumor cells controls NK cell-dependent tumor surveillance. Our findings indicate that STAT3 inhibition in lymphoma patients will impair NK cell-mediated tumor surveillance, which needs to be taken into account when testing STAT3 inhibitors in preclinical or clinical trials.

  20. Loss of STAT3 in Lymphoma Relaxes NK Cell-Mediated Tumor Surveillance

    Energy Technology Data Exchange (ETDEWEB)

    Putz, Eva Maria [Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Veterinaerplatz 1, Vienna 1210 (Austria); Hoelzl, Maria Agnes [Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna (MUV), Waehringer Strasse 13A, Vienna 1090 (Austria); Baeck, Julia [Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Veterinaerplatz 1, Vienna 1210 (Austria); Bago-Horvath, Zsuzsanna [Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Veterinaerplatz 1, Vienna 1210 (Austria); Clinical Institute of Pathology, Medical University of Vienna (MUV), Waehringer Gürtel 18-20, Vienna 1090 (Austria); Schuster, Christian [Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna (MUV), Waehringer Strasse 13A, Vienna 1090 (Austria); Reichholf, Brian [Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Veterinaerplatz 1, Vienna 1210 (Austria); Kern, Daniela; Aberger, Fritz [Department of Molecular Biology, University of Salzburg, Hellbrunnerstrasse 34, Salzburg 5020 (Austria); Sexl, Veronika; Hoelbl-Kovacic, Andrea, E-mail: andrea.hoelbl@vetmeduni.ac.at [Institute of Pharmacology and Toxicology, University of Veterinary Medicine, Veterinaerplatz 1, Vienna 1210 (Austria)

    2014-01-27

    The transcription factors and proto-oncogenes STAT3 and STAT5 are highly activated in hematological malignancies and represent promising therapeutic targets. Whereas the importance of STAT5 as tumor promoter is beyond doubt, the role of STAT3 in hematological cancers is less well understood. Both, enforced as well as attenuated expression of STAT3 were reported in hematopoietic malignancies. Recent evidence implicates STAT3 as key player for tumor immune surveillance as it both mediates the production of and response to inflammatory cytokines. Here we investigated the effects of STAT3 deletion in a BCR/ABL-induced lymphoma model, which is tightly controlled by natural killer (NK) cells in vivo. Upon STAT3 deletion tumor growth is significantly enhanced when compared to STAT3-expressing controls. The increased tumor size upon loss of STAT3 was accompanied by reduced NK cell infiltration and decreased levels of the cytokine IFN-γ and the chemokine RANTES. Upon transplantation into NK cell-deficient mice differences in lymphoma size were abolished indicating that STAT3 expression in the tumor cells controls NK cell-dependent tumor surveillance. Our findings indicate that STAT3 inhibition in lymphoma patients will impair NK cell-mediated tumor surveillance, which needs to be taken into account when testing STAT3 inhibitors in preclinical or clinical trials.

  1. Signal transducer and activator of transcription-3 (STAT-3) and psoriasis%信号传导与转录激活因子-3与银屑病

    Institute of Scientific and Technical Information of China (English)

    彭友华; 李建军

    2010-01-01

    信号传导与转录激活因子-3是一种重要的核转录因子,能被白介素-6、表皮生长因子等细胞因子和生长因子激活,参与细胞增殖、存活、转化、迁移等过程.在银屑病皮损中,角质形成细胞中的信号传导与转录激活因子-3几乎都呈激活状态,它能通过调节银屑病相关发病基因和细胞因子的表达,参与角质形成细胞的增殖、分化和存活以及皮损中血管发生,是银屑病发病中重要的信号传导与转录激活因子.%As an important nuclear transcription factor, STAT-3 can be activated by numerous cytokines and growth factors such as interleukin (IL)-6, epidermal growth factor (EGF), and so on. STAT-3 participates in cell proliferation, survival, transformation, migration and other biological processes. In psoriatic lesions, almost all STAT-3 is activated in keratinocytes and it takes part in cell proliferation, differentiation and survival of keratinocytes as well as angiogenesis by regulating the expression of psoriasis-related genes and cytokines. STAT-3 is an important signal transduction factor and activator of transcription in the pathogenesis of psoriasis.

  2. Mitochondrial Localized Stat3 Promotes Breast Cancer Growth via Phosphorylation of Serine 727*

    Science.gov (United States)

    Zhang, Qifang; Raje, Vidisha; Yakovlev, Vasily A.; Yacoub, Adly; Szczepanek, Karol; Meier, Jeremy; Derecka, Marta; Chen, Qun; Hu, Ying; Sisler, Jennifer; Hamed, Hossein; Lesnefsky, Edward J.; Valerie, Kristoffer; Dent, Paul; Larner, Andrew C.

    2013-01-01

    Signal transducer and activator of transcription 3 (Stat3) is a key mediator in the development of many cancers. For 20 years, it has been assumed that Stat3 mediates its biological activities as a nuclear localized transcription factor activated by many cytokines. However, recent studies from this laboratory and others indicate that Stat3 has an independent function in the mitochondria (mitoStat3) where it controls the activity of the electron transport chain (ETC) and mediates Ras-induced transformation of mouse embryo fibroblasts. The actions of mitoStat3 in controlling respiration and Ras transformation are mediated by the phosphorylation state of serine 727. To address the role of mitoStat3 in the pathogenesis of cells that are transformed, we used 4T1 breast cancer cells, which form tumors that metastasize in immunocompetent mice. Substitution of Ser-727 for an alanine or aspartate in Stat3 that has a mitochondrial localization sequence, MLS-Stat3, has profound effects on tumor growth, complex I activity of the ETC, and accumulation of reactive oxygen species (ROS). Cells expressing MLS-Stat3(S727A) display slower tumor growth, decreased complex I activity of the ETC, and increased ROS accumulation under hypoxia compared with cells expressing MLS-Stat3. In contrast, cells expressing MLS-Stat3(S727D) show enhanced tumor growth and complex I activity and decreased production of ROS. These results highlight the importance of serine 727 of mitoStat3 in breast cancer and suggest a novel role for mitoStat3 in regulation of ROS concentrations through its action on the ETC. PMID:24019511

  3. Modulation of STAT3 folding and function by TRiC/CCT chaperonin.

    Directory of Open Access Journals (Sweden)

    Moses Kasembeli

    2014-04-01

    Full Text Available Signal transducer and activator of transcription 3 (Stat3 transduces signals of many peptide hormones from the cell surface to the nucleus and functions as an oncoprotein in many types of cancers, yet little is known about how it achieves its native folded state within the cell. Here we show that Stat3 is a novel substrate of the ring-shaped hetero-oligomeric eukaryotic chaperonin, TRiC/CCT, which contributes to its biosynthesis and activity in vitro and in vivo. TRiC binding to Stat3 was mediated, at least in part, by TRiC subunit CCT3. Stat3 binding to TRiC mapped predominantly to the β-strand rich, DNA-binding domain of Stat3. Notably, enhancing Stat3 binding to TRiC by engineering an additional TRiC-binding domain from the von Hippel-Lindau protein (vTBD, at the N-terminus of Stat3, further increased its affinity for TRiC as well as its function, as determined by Stat3's ability to bind to its phosphotyrosyl-peptide ligand, an interaction critical for Stat3 activation. Thus, Stat3 levels and function are regulated by TRiC and can be modulated by manipulating its interaction with TRiC.

  4. STAT3 Regulates Proliferation and Immunogenicity of the Ewing Family of Tumors In Vitro

    Directory of Open Access Journals (Sweden)

    Sam Behjati

    2012-01-01

    Full Text Available The Ewing sarcoma family of tumors (ESFT represents an aggressive spectrum of malignant tumour types with common defining histological and cytogenetic features. To evaluate the functional activation of signal transducer and activator of transcription 3 (STAT3 in ESFT, we evaluated its activation in primary tissue sections and observed the functional consequences of its inhibition in ESFT cell lines. STAT3 was activated (tyrosine 705-phosphorylated in 18 out of 31 primary tumours (58%, either diffusely (35% or focally (23%. STAT3 was constitutively activated in 3 out of 3 ESFT cell lines tested, and its specific chemical inhibition resulted in complete loss of cell viability. STAT3 inhibition in ESFT cell lines was associated with several consistent changes in chemokine profile suggesting a role of STAT3 in ESFT in both cell survival and modification of the cellular immune environment. Together these data support the investigation of STAT3 inhibitors for the Ewing family of tumors.

  5. Nifuroxazide inhibits survival of multiple myeloma cells by directly inhibiting STAT3.

    Science.gov (United States)

    Nelson, Erik A; Walker, Sarah R; Kepich, Alicia; Gashin, Laurie B; Hideshima, Teru; Ikeda, Hiroshi; Chauhan, Dharminder; Anderson, Kenneth C; Frank, David A

    2008-12-15

    Constitutive activation of the transcription factor STAT3 contributes to the pathogenesis of many cancers, including multiple myeloma (MM). Since STAT3 is dispensable in most normal tissue, targeted inhibition of STAT3 is an attractive therapy for patients with these cancers. To identify STAT3 inhibitors, we developed a transcriptionally based assay and screened a library of compounds known to be safe in humans. We found the drug nifuroxazide to be an effective inhibitor of STAT3 function. Nifuroxazide inhibits the constitutive phosphorylation of STAT3 in MM cells by reducing Jak kinase autophosphorylation, and leads to down-regulation of the STAT3 target gene Mcl-1. Nifuroxazide causes a decrease in viability of primary myeloma cells and myeloma cell lines containing STAT3 activation, but not normal peripheral blood mononuclear cells. Although bone marrow stromal cells provide survival signals to myeloma cells, nifuroxazide can overcome this survival advantage. Reflecting the interaction of STAT3 with other cellular pathways, nifuroxazide shows enhanced cytotoxicity when combined with either the histone deacetylase inhibitor depsipeptide or the MEK inhibitor UO126. Therefore, using a mechanistic-based screen, we identified the clinically relevant drug nifuroxazide as a potent inhibitor of STAT signaling that shows cytotoxicity against myeloma cells that depend on STAT3 for survival. PMID:18824601

  6. Transcription Factor STAT3 as a Novel Molecular Target for Cancer Prevention

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Ailian; Yang, Zhengduo [Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 (United States); Shen, Yicheng [College of Natural Sciences, The University of Texas at Austin, Austin, TX 78712 (United States); Zhou, Jia [Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555 (United States); Shen, Qiang, E-mail: qshen@mdanderson.org [Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030 (United States)

    2014-04-16

    Signal Transducers and Activators of Transcription (STATs) are a family of transcription factors that regulate cell proliferation, differentiation, apoptosis, immune and inflammatory responses, and angiogenesis. Cumulative evidence has established that STAT3 has a critical role in the development of multiple cancer types. Because it is constitutively activated during disease progression and metastasis in a variety of cancers, STAT3 has promise as a drug target for cancer therapeutics. Recently, STAT3 was found to have an important role in maintaining cancer stem cells in vitro and in mouse tumor models, suggesting STAT3 is integrally involved in tumor initiation, progression and maintenance. STAT3 has been traditionally considered as nontargetable or undruggable, and the lag in developing effective STAT3 inhibitors contributes to the current lack of FDA-approved STAT3 inhibitors. Recent advances in cancer biology and drug discovery efforts have shed light on targeting STAT3 globally and/or specifically for cancer therapy. In this review, we summarize current literature and discuss the potential importance of STAT3 as a novel target for cancer prevention and of STAT3 inhibitors as effective chemopreventive agents.

  7. Δ9-Tetrahydrocannabinol-mediated epigenetic modifications elicit myeloid-derived suppressor cell activation via STAT3/S100A8.

    Science.gov (United States)

    Sido, Jessica Margaret; Yang, Xiaoming; Nagarkatti, Prakash S; Nagarkatti, Mitzi

    2015-04-01

    MDSCs are potent immunosuppressive cells that are induced during inflammatory responses, as well as by cancers, to evade the anti-tumor immunity. We recently demonstrated that marijuana cannabinoids are potent inducers of MDSCs. In the current study, we investigated the epigenetic mechanisms through which THC, an exogenous cannabinoid, induces MDSCs and compared such MDSCs with the naïve MDSCs found in BM of BL6 (WT) mice. Administration of THC into WT mice caused increased methylation at the promoter region of DNMT3a and DNMT3b in THC-induced MDSCs, which correlated with reduced expression of DNMT3a and DNMT3b. Furthermore, promoter region methylation was decreased at Arg1 and STAT3 in THC-induced MDSCs, and consequently, such MDSCs expressed higher levels of Arg1 and STAT3. In addition, THC-induced MDSCs secreted elevated levels of S100A8, a calcium-binding protein associated with accumulation of MDSCs in cancer models. Neutralization of S100A8 by use of anti-S100A8 (8H150) in vivo reduced the ability of THC to trigger MDSCs. Interestingly, the elevated S100A8 expression also promoted the suppressive function of MDSCs. Together, the current study demonstrates that THC mediates epigenetic changes to promote MDSC differentiation and function and that S100A8 plays a critical role in this process. PMID:25713087

  8. Stat3 induces oncogenic Skp2 expression in human cervical carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hanhui [Shanghai Medical College of Fudan University, Shanghai 200032 (China); Zhao, Wenrong [Department of Gynecology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai 200011 (China); Yang, Dan, E-mail: yangdandr@gmail.com [Department of Gynecology, Shanghai First Maternity and Infant Hospital, Tongji University, Shanghai 200040 (China)

    2012-02-03

    Highlights: Black-Right-Pointing-Pointer Upregulation of Skp2 by IL-6 or Stat3 activation. Black-Right-Pointing-Pointer Stat3 activates Skp2 expression through bound to its promoter region. Black-Right-Pointing-Pointer Stat3 activates Skp2 expression through recruitment of P300. Black-Right-Pointing-Pointer Stat3 activation decreases the P27 stability. -- Abstract: Dysregulated Skp2 function promotes cell proliferation, which is consistent with observations of Skp2 over-expression in many types of human cancers, including cervical carcinoma (CC). However, the molecular mechanisms underlying elevated Skp2 expression have not been fully explored. Interleukin-6 (IL-6) induced Stat3 activation is viewed as crucial for multiple tumor growth and metastasis. Here, we demonstrate that Skp2 is a direct transcriptional target of Stat3 in the human cervical carcinoma cells. Our data show that IL-6 administration or transfection of a constitutively activated Stat3 in HeLa cells activates Skp2 mRNA transcription. Using luciferase reporter and ChIP assays, we show that Stat3 binds to the promoter region of Skp2 and promotes its activity through recruiting P300. As a result of the increase of Skp2 expression, endogenous p27 protein levels are markedly decreased. Thus, our results suggest a previously unknown Stat3-Skp2 molecular network controlling cervical carcinoma development.

  9. Role of STAT3 in in vitro transformation triggered by TRK oncogenes.

    Directory of Open Access Journals (Sweden)

    Claudia Miranda

    Full Text Available TRK oncoproteins are chimeric versions of the NTRK1/NGF receptor and display constitutive tyrosine kinase activity leading to transformation of NIH3T3 cells and neuronal differentiation of PC12 cells. Signal Transducer and Activator of Transcription (STAT 3 is activated in response to cytokines and growth factors and it has been recently identified as a novel signal transducer for TrkA, mediating the functions of NGF in nervous system. In this paper we have investigated STAT3 involvement in signalling induced by TRK oncogenes. We showed that TRK oncogenes trigger STAT3 phosphorylation both on Y705 and S727 residues and STAT3 transcriptional activity. MAPK pathway was involved in the induction of STAT3 phosphorylation. Interestingly, we have shown reduced STAT3 protein level in NIH3T3 transformed foci expressing TRK oncogenes. Overall, we have unveiled a dual role for STAT3 in TRK oncogenes-induced NIH3T3 transformation: i decreased STAT3 protein levels, driven by TRK oncoproteins activity, are associated to morphological transformation; ii residual STAT3 transcriptional activity is required for cell growth.

  10. Binding modes of peptidomimetics designed to inhibit STAT3.

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    Ankur Dhanik

    Full Text Available STAT3 is a transcription factor that has been found to be constitutively activated in a number of human cancers. Dimerization of STAT3 via its SH2 domain and the subsequent translocation of the dimer to the nucleus leads to transcription of anti-apoptotic genes. Prevention of the dimerization is thus an attractive strategy for inhibiting the activity of STAT3. Phosphotyrosine-based peptidomimetic inhibitors, which mimic pTyr-Xaa-Yaa-Gln motif and have strong to weak binding affinities, have been previously investigated. It is well-known that structures of protein-inhibitor complexes are important for understanding the binding interactions and designing stronger inhibitors. Experimental structures of inhibitors bound to the SH2 domain of STAT3 are, however, unavailable. In this paper we describe a computational study that combined molecular docking and molecular dynamics to model structures of 12 peptidomimetic inhibitors bound to the SH2 domain of STAT3. A detailed analysis of the modeled structures was performed to evaluate the characteristics of the binding interactions. We also estimated the binding affinities of the inhibitors by combining MMPB/GBSA-based energies and entropic cost of binding. The estimated affinities correlate strongly with the experimentally obtained affinities. Modeling results show binding modes that are consistent with limited previous modeling studies on binding interactions involving the SH2 domain and phosphotyrosine(pTyr-based inhibitors. We also discovered a stable novel binding mode that involves deformation of two loops of the SH2 domain that subsequently bury the C-terminal end of one of the stronger inhibitors. The novel binding mode could prove useful for developing more potent inhibitors aimed at preventing dimerization of cancer target protein STAT3.

  11. Silymarin suppresses the PGE2 -induced cell migration through inhibition of EP2 activation; G protein-dependent PKA-CREB and G protein-independent Src-STAT3 signal pathways.

    Science.gov (United States)

    Woo, Seon Min; Min, Kyoung-Jin; Chae, In Gyeong; Chun, Kyung-Soo; Kwon, Taeg Kyu

    2015-03-01

    Silymarin has been known as a chemopreventive agent, and possesses multiple anti-cancer activities including induction of apoptosis, inhibition of proliferation and growth, and blockade of migration and invasion. However, whether silymarin could inhibit prostaglandin (PG) E2 -induced renal cell carcinoma (RCC) migration and what are the underlying mechanisms are not well elucidated. Here, we found that silymarin markedly inhibited PGE2 -stimulated migration. PGE2 induced G protein-dependent CREB phosphorylation via protein kinase A (PKA) signaling, and PKA inhibitor (H89) inhibited PGE2 -mediated migration. Silymarin reduced PGE2 -induced CREB phosphorylation and CRE-promoter activity. PGE2 also activated G protien-independent signaling pathways (Src and STAT3) and silymarin reduced PGE2 -induced phosphorylation of Src and STAT3. Inhibitor of Src (Saracatinib) markedly reduced PGE2 -mediated migration. We found that EP2, a PGE2 receptor, is involved in PGE2 -mediated cell migration. Down regulation of EP2 by EP2 siRNA and EP2 antagonist (AH6809) reduced PGE2 -inudced migration. In contrast, EP2 agonist (Butaprost) increased cell migration and silymarin effectively reduced butaprost-mediated cell migration. Moreover, PGE2 increased EP2 expression through activation of positive feedback mechanism, and PGE2 -induced EP2 expression, as well as basal EP2 levels, were reduced in silymarin-treated cells. Taken together, our study demonstrates that silymarin inhibited PGE2 -induced cell migration through inhibition of EP2 signaling pathways (G protein dependent PKA-CREB and G protein-independent Src-STAT3).

  12. STAT3-Decoy ODN Inhibits Cytokine Autocrine of Murine Tumor Cells

    Institute of Scientific and Technical Information of China (English)

    Xi Liu; Jiayi Li; Jian Zhang

    2007-01-01

    Tumor cells usually secrete soluble factors to improve their proliferation via autocrine network or to escape from immune surveillance by inhibiting antitumor immunity, among these factors IL-10 and IL-6 play more important roles. Since both cytokines' signal transductions are mediated through the STAT3 pathway, STAT3 becomes an attractive target for tumor therapy. In present study, STAT3 of murine tumor cell lines B16 and MCA-38 was constitutively activated. After treatment with STAT3-decoy ODN, the proliferation of these tumor cells was inhibited and the transcription of IL-10 or IL-6 in tumor cells was down-regulated. These results suggested that STAT3 is a good target candidate, and STAT3-decoy ODN may possibly be used as a strategy for breaking both tumor autocrine network and tumor immunotolerance.

  13. IL-6/STAT3 axis initiated CAFs via up-regulating TIMP-1 which was attenuated by acetylation of STAT3 induced by PCAF in HCC microenvironment.

    Science.gov (United States)

    Zheng, Xin; Xu, Meng; Yao, Bowen; Wang, Cong; Jia, Yuli; Liu, Qingguang

    2016-09-01

    Aberrant tumor microenvironment is involved closely in tumor initiation and progression, in which cancer associated fibroblasts (CAFs) play a pivotal role. Both IL-6/STAT3 signaling and TIMP-1 have been found to modulate the crosstalk between tumor cells and CAFs in tumor microenvironment, however, the underlying mechanism remains unclear. Here, we showed that IL-6/STAT3 signaling was activated aberrantly in HCC tissues and correlated with poor post-surgical outcome. The in vitro experiments confirmed that activation of IL-6/STAT3 pathway enhanced TIMP-1 expression directly via phosphorylated STATs (p-STAT3)-binding with TIMP-1 promoter in Huh7 cells. Furthermore, activation of IL-6/STAT3 pathway in HCC cells was shown to induce the transformation from normal liver fibroblasts (LFs) to CAFs via up-regulating TIMP-1 expression. Co-culture with CAFs promoted the growth of Huh7 cells both in vitro and in vivo. Finally, by co-Immunoprecipitation and immunoblotting assessments, PCAF, a well-known acetyltransferase, was revealed to acetylate cytoplasmic STAT3 protein directly and regulate TIMP-1 expression negatively in Huh7 cells. In summary, this investigation indicated that there was a positive IL-6/TIMP-1 feedback loop controlling the crosstalk between HCC cells and its neighbouring fibroblasts. The data here also identified that PCAF repressed TIMP-1 expression via acetylation of STAT3. In conclusion, this investigation demonstrated that CAFs promoted HCC growth via IL-6/STAT3/AKT pathway and TIMP-1 over-expression driven by IL-6/STAT3 pathway in HCC cells brought in more CAFs through activating LFs. Finally, PCAF could block this positive feedback by acetylating STAT3 in HCC cells.

  14. Clinical Implications of Phosphorylated STAT3 Expression in de novo Diffuse Large B-cell Lymphoma

    DEFF Research Database (Denmark)

    Ok, Chi Y; Chen, Jiayu; Xu-Monette, Ziju;

    2014-01-01

    PURPOSE: Activated signal transducer and activator of transcription 3 (STAT3) regulates tumor growth, invasion, cell proliferation, angiogenesis, immune response, and survival. Data regarding expression of phosphorylated (activated) STAT3 in diffuse large B-cell lymphoma (DLBCL) and the impact of...

  15. Inhibition of STAT3 reverses alkylator resistance through modulation of the AKT and β-catenin signaling pathways.

    Science.gov (United States)

    Wang, Yongzhi; Chen, Lingchao; Bao, Zhaoshi; Li, Shouwei; You, Gan; Yan, Wei; Shi, Zhendong; Liu, Yanwei; Yang, Pei; Zhang, Wei; Han, Lei; Kang, Chunsheng; Jiang, Tao

    2011-11-01

    Activation of signal transducer and activator of transcription 3 (STAT3) is associated with poor clinical outcome of glioblastoma (GBM). However, the role of STAT3 in resistance to alkylator-based chemotherapy remains unknown. Here, we retrospectively analyzed the phosphorylated STAT3 (p-STAT3) profile of 68 GBM patients receiving alkylator therapy, identifying p-STAT3 as an independent unfavorable prognostic factor for progression-free and overall survival. Additionally, elevated p-STAT3 expression correlated with resistance to alkylator therapy. In vitro analysis revealed that U251 and U87 human glioma cells were refractory to treatment with the common alkylating agent temozolomide (TMZ), with only a modest impact on AKT and β-catenin activation in the context of high p-STAT3. Inhibition of STAT3 in these cells significantly enhanced the effect of TMZ. Inhibition of STAT3 dramatically decreased the IC50 of TMZ, increasing TMZ-induced apoptosis while up-regulating expression of Bcl-2 and down-regulating expression of Bax. Furthermore, inhibition of STAT3 increased TMZ-induced G₀-G₁ arrest and decreased Cyclin D1 expression compared to TMZ alone. Together, these results indicate that inhibition of STAT3 sensitizes glioma cells to TMZ, at least in part, by blocking the p-AKT and β-catenin pathways. These findings strongly support the hypothesis that STAT3 inhibition significantly improves the clinical efficacy of alkylating agents.

  16. Unveiling the Association of STAT3 and HO-1 in Prostate Cancer: Role beyond Heme Degradation

    Directory of Open Access Journals (Sweden)

    Belen Elguero

    2012-11-01

    Full Text Available Activation of the androgen receptor (AR is a key step in the development of prostate cancer (PCa. Several mechanisms have been identified in AR activation, among them signal transducer and activator of transcription 3 (STAT3 signaling. Disruption of STAT3 activity has been associated to cancer progression. Recent studies suggest that heme oxygenase 1 (HO-1 may play a key role in PCa that may be independent of its catalytic function. We sought to explore whether HO-1 operates on AR transcriptional activity through the STAT3 axis. Our results display that HO-1 induction in PCa cells represses AR activation by decreasing the prostate-specific antigen (PSA promoter activity and mRNA levels. Strikingly, this is the first report to show by chromatin immunoprecipitation analysis that HO-1 associates to gene promoters, revealing a novel function for HO-1 in the nucleus. Furthermore, HO-1 and STAT3 directly interact as determined by co-immunoprecipitation studies. Forced expression of HO-1 increases STAT3 cytoplasmic retention. When PCa cells were transfected with a constitutively active STAT3 mutant, PSA and STAT3 downstream target genes were abrogated under hemin treatment. Additionally, a significant decrease in pSTAT3 protein levels was detected in the nuclear fraction of these cells. Confocal microscopy images exhibit a decreased rate of AR/STAT3 nuclear co-localization under hemin treatment. In vivo studies confirmed that STAT3 nuclear delimitation was significantly decreased in PC3 tumors overexpressing HO-1 grown as xenografts in nude mice. These results provide a novel function for HO-1 down-modulating AR transcriptional activity in PCa, interfering with STAT3 signaling, evidencing its role beyond heme degradation.

  17. STAT3和胃癌的研究进展

    Institute of Scientific and Technical Information of China (English)

    张荣贵

    2011-01-01

    @@ 人类STAT3基因定位于第17号染色体(q21.31),STAT3蛋白是信号转导子与转录激活子家族(signal transducers and activators of transcription ,STATs)的重要成员.近年来,STAT3与胃癌(gastric cancer,GC)关系引起人们的广泛关注,现就其研究进展作一综述. 一、STAT3概述

  18. STAT3 Regulates ABCA3 Expression and Influences Lamellar Body Formation in Alveolar Type II Cells

    OpenAIRE

    Matsuzaki, Yohei; Besnard, Valérie; Clark, Jean C.; Xu, Yan; Wert, Susan E.; Ikegami, Machiko; Whitsett, Jeffrey A.

    2007-01-01

    ATP-Binding Cassette A3 (ABCA3) is a lamellar body associated lipid transport protein required for normal synthesis and storage of pulmonary surfactant in type II cells in the alveoli. In this study, we demonstrate that STAT3, activated by IL-6, regulates ABCA3 expression in vivo and in vitro. ABCA3 mRNA and immunostaining were decreased in adult mouse lungs in which STAT3 was deleted from the respiratory epithelium (Stat3Δ/Δ mice). Consistent with the role of STAT3, intratracheal IL-6 induce...

  19. Paeoniflorin inhibits human glioma cells via STAT3 degradation by the ubiquitin–proteasome pathway

    Science.gov (United States)

    Nie, Xiao-hu; Ou-yang, Jia; Xing, Ying; Li, Dan-yan; Dong, Xing-yu; Liu, Ru-en; Xu, Ru-xiang

    2015-01-01

    We investigated the underlying mechanism for the potent proapoptotic effect of paeoniflorin (PF) on human glioma cells in vitro, focusing on signal transducer and activator of transcription 3 (STAT3) signaling. Significant time- and dose-dependent apoptosis and inhibition of proliferation were observed in PF-treated U87 and U251 glioma cells. Expression of STAT3, its active form phosphorylated STAT3 (p-STAT3), and several downstream molecules, including HIAP, Bcl-2, cyclin D1, and Survivin, were significantly downregulated upon PF treatment. Overexpression of STAT3 induced resistance to PF, suggesting that STAT3 was a critical target of PF. Interestingly, rapid downregulation of STAT3 was consistent with its accelerated degradation, but not with its dephosphorylation or transcriptional modulation. Using specific inhibitors, we demonstrated that the prodegradation effect of PF on STAT3 was mainly through the ubiquitin–proteasome pathway rather than via lysosomal degradation. These findings indicated that PF-induced growth suppression and apoptosis in human glioma cells through the proteasome-dependent degradation of STAT3. PMID:26508835

  20. STAT3 and metabolism : how many ways to use a single molecule?

    NARCIS (Netherlands)

    Demaria, Marco; Camporeale, Annalisa; Poli, Valeria

    2014-01-01

    The transcription factor Signal Transducer and Activator of Transcription (STAT)3 has been considered as a potential anticancer target since its first description as an oncogene in 1999, recently leading to STAT3 inhibitors been brought to clinical trial for the treatment of solid tumors. However, t

  1. Knockdown of STAT3 expression by RNAi induces apoptosis in astrocytoma cells

    Directory of Open Access Journals (Sweden)

    Kruger Mathew M

    2003-09-01

    Full Text Available Abstract Background Astrocytomas are the most common type of primary central nervous system tumors. They are frequently associated with genetic mutations that deregulate cell cycle and render these tumors resistant to apoptosis. STAT3, signal transducer and activator of transcription 3, participates in several human cancers by inducing cell proliferation and inhibiting apoptosis and is frequently activated in astrocytomas. Methods RNA interference was used to knockdown STAT3 expression in human astrocytes and astrocytoma cell lines. The effect of STAT3 knockdown on apoptosis, cell proliferation, and gene expression was then assessed by standard methods. Results We have found that STAT3 is constitutively activated in several human astrocytoma cell lines. Knockdown of STAT3 expression by siRNA induces morphologic and biochemical changes consistent with apoptosis in several astrocytoma cell lines, but not in primary human astrocytes. Moreover, STAT3 is required for the expression of the antiapoptotic genes survivin and Bcl-xL in the A172 glioblastoma cell line. Conclusion These results show that STAT3 is required for the survival of some astrocytomas. These studies suggest STAT3 siRNA could be a useful therapeutic agent for the treatment of astrocytomas.

  2. Inhibition of STAT3 expression by siRNA suppresses growth and induces apoptosis in laryngeal cancer cells

    Institute of Scientific and Technical Information of China (English)

    Li-fang GAO; De-qi XU; Lian-ji WEN; Xing-yi ZHANG; Yue-ting SHAO; Xue-jian ZHAO

    2005-01-01

    Aim: To determine the inhibitory effect of the synthetic STAT3 siRNA on the expression of STAT3 gene in human laryngeal cancer cell lines Hep2 and to investigate the effect of STAT3 siRNA on growth and apoptosis in Hep2 cells. Methods:A pair of DNA templates coding siRNA against STAT3-mRNA was synthesized to reconstruct plasmid of pSilencerl.0-U6 siRNA-STAT3. Hep2 cells were transfected with RPMI-1640 media (untreated), plasmid (empty), and STAT3 siRNA,respectively. Northern blot and Western blot analysis of STAT3 and pTyr-STAT3 expression in Hep2 cells and Western blot analysis of Bcl-2 expression in the Hep2 cell was performed 72 h after transfection. MTT, flow cytometry, and AO/EB assay were used for determination of cells proliferation and apoptosis in Hep2 cells. Results: pTyr-STAT3 was markedly expressed in untreated Hep2 cells and the vector-treated Hep2 cells, whereas pTyr-STAT3 expression was significantly reduced in STAT3 siRNA-transfected Hep2 cells, indicating that STAT3 siRNA inhibited the activity of STAT3. Transfection of Hep2 cells with STAT3 siRNA significantly inhibited STAT3 expression at both mRNA and protein level in Hep2 cells and the inhibition was characterized by time-dependent transfection. Treatment of Hep2 cells with STAT3 siRNA resulted in dose-dependent growth inhibition of Hep2, this significantly increased apoptotic cell rate, and decreased Bcl-2 expression level in Hep2 cells. STAT3 siRNA had an effect on induction of either early or late stage apoptosis. Conclusion: This study demonstrates that STAT3 siRNA effectively inhibits STAT3 gene expression in Hep2 cells leading to growth suppression and induction of apoptosis in Hep2 cells. The use of siRNA technique may provide a novel therapeutic approach to treat laryngeal cancer and other malignant tumors expressing constitutively activated STAT3.

  3. Plasmid-based Stat3 siRNA delivered by hydroxyapatite nanoparticles suppresses mouse prostate tumour growth in vivo

    Institute of Scientific and Technical Information of China (English)

    Zuo-Wen Liang; Ling Zhang; Bao-Xue Yang; Bao-Feng Guo; Yang Li; Xiao-Jie Li; Xin Li; Li-Ting Zhao; Ii-Fang Gao; Hao Yu; Xue-Jian Zhao

    2011-01-01

    DNA vector-based Stat3-specific RNA interference (si-Stat3) blocks Stat3 signalling and inhibits prostate tumour growth. However, the antitumour activity depends on the efficient delivery of si-Stat3. The effects on the growth of mouse prostate cancer cells of si-Stat3 delivered by hydroxyapatite were determined in this study. RM-1 tumour blocks were transplanted into C57BL/6 mice. CaCl2-modif ied hydroxyapatite carrying si-Stat3 plasmids were injected into tumours, and tumour growth and histology were determined. The expression levels of Stat3, pTyr-Stat3, Bcl-2, Bax, Caspase3, VEGF and cyclin Dl were measured by western blot analysis. Amounts of apoptosis in cancer cells were analysed with immunohistochemistry and the terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) assay. The results showed that hydroxyapatite-delivered si-Stat3 significantly suppressed tumour growth up to 74% (P<0.01). Stat3 expression was dramatically downregulated in the tumours. The immunohistochemistry and TUNEL results showed that si-Stet3-induced apoptosis (up to 42%, P<0.01). The Stat3 downstream genes Bcl-2, VEGFand cyclin Dl were also strongly downregulated in the tumour tissues that also displayed significant increases in Bax expression and Caspase3 activity. These results suggest that hydroxyapatite can be used for the in vivo delivery of plasmid-based siRNAs into tumours.

  4. Stat3 signaling regulates embryonic stem cell fate in a dose-dependent manner

    Directory of Open Access Journals (Sweden)

    Chih-I Tai

    2014-09-01

    Full Text Available Stat3 is essential for mouse embryonic stem cell (mESC self-renewal mediated by LIF/gp130 receptor signaling. Current understanding of Stat3-mediated ESC self-renewal mechanisms is very limited, and has heretofore been dominated by the view that Stat3 signaling functions in a binary “on/off” manner. Here, in contrast to this binary viewpoint, we demonstrate a contextual, rheostat-like mechanism for Stat3's function in mESCs. Activation and expression levels determine whether Stat3 functions in a self-renewal or a differentiation role in mESCs. We also show that Stat3 induces rapid differentiation of mESCs toward the trophectoderm (TE lineage when its activation level exceeds certain thresholds. Stat3 induces this differentiation phenotype via induction of Tfap2c and its downstream target Cdx2. Our findings provide a novel concept in the realm of Stat3, self-renewal signaling, and pluripotent stem cell biology. Ultimately, this finding may facilitate the development of conditions for the establishment of authentic non-rodent ESCs.

  5. The Multifaceted Roles of STAT3 Signaling in the Progression of Prostate Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, Jennifer L.; Thaper, Daksh; Zoubeidi, Amina, E-mail: azoubeidi@prostatecentre.com [The Vancouver Prostate Centre, Department of Urologic Sciences, University of British Columbia, 2660 Oak Street, Vancouver British Columbia, V6H 3Z6 (Canada)

    2014-04-09

    The signal transducer and activator of transcription (STAT)3 governs essential functions of epithelial and hematopoietic cells that are often dysregulated in cancer. While the role for STAT3 in promoting the progression of many solid and hematopoietic malignancies is well established, this review will focus on the importance of STAT3 in prostate cancer progression to the incurable metastatic castration-resistant prostate cancer (mCRPC). Indeed, STAT3 integrates different signaling pathways involved in the reactivation of androgen receptor pathway, stem like cells and the epithelial to mesenchymal transition that drive progression to mCRPC. As equally important, STAT3 regulates interactions between tumor cells and the microenvironment as well as immune cell activation. This makes it a major factor in facilitating prostate cancer escape from detection of the immune response, promoting an immunosuppressive environment that allows growth and metastasis. Based on the multifaceted nature of STAT3 signaling in the progression to mCRPC, the promise of STAT3 as a therapeutic target to prevent prostate cancer progression and the variety of STAT3 inhibitors used in cancer therapies is discussed.

  6. The dark and the bright side of Stat3: proto-oncogene and tumor-suppressor.

    Science.gov (United States)

    Ecker, Andrea; Simma, Olivia; Hoelbl, Andrea; Kenner, Lukas; Beug, Hartmut; Moriggl, Richard; Sexl, Veronika

    2009-01-01

    Stat transcription factors have been implicated in tumorigenesis in mice and men. Stat3 and Stat5 are considered powerful proto-oncogenes, whereas Stat1 has been demonstrated to suppress tumor formation. We demonstrate here for the first time that a constitutive active version of Stat3alpha (Stat3alphaC) may also suppress transformation. Mouse embryonic fibroblasts (MEFs) deficient for p53 can be transformed with either c-myc or with rasV12 alone. Interestingly, transformation by c-myc is efficiently suppressed by co-expression of Stat3alphaC, but Stat3alphaC does not interfere with transformation by the rasV12-oncogene. In contrast, transplantation of bone marrow cells expressing Stat3alphaC induces the formation of a highly aggressive T cell leukemia in mice. The leukemic cells invaded multiple organs including lung, heart, salivary glands, liver and kidney. Interestingly, transplanted mice developed a similar leukemia when the bone marrow cells were transduced with Stat3beta, which is also constitutively active when expressed at significant levels. Our experiments demonstrate that Stat3 has both - tumor suppressing and tumor promoting properties.

  7. Interferon alpha antagonizes STAT3 and SOCS3 signaling triggered by hepatitis C virus.

    Science.gov (United States)

    Zhao, Lan-Juan; He, Sheng-Fei; Wang, Wen; Ren, Hao; Qi, Zhong-Tian

    2016-04-01

    We aimed to investigate regulation of signal transducer and activator of transcription 3 (STAT3) and suppressor of cytokine signaling 3 (SOCS3) by interferon alpha (IFN-α) and to analyze the relationship between STAT3 and SOCS3 during hepatitis C virus (HCV) infection. Changes in STAT3 and SOCS3 were analyzed at both mRNA and protein levels in human hepatoma cells infected with HCV (J6/JFH1). At 72h of HCV infection, STAT3 expression was decreased with sustained phosphorylation, and IFN-α increased such decrease and phosphorylation. HCV increased SOCS3 expression, while IFN-α impaired such increase, indicating different regulation of STAT3 and SOCS3 by IFN-α. IFN-α-induced expression and phosphorylation of upstream kinases of the JAK/STAT pathway, Tyk2 and Jak1, were suppressed by HCV. Moreover, knockdown of STAT3 by RNA interference led to decreases in HCV RNA replication and viral protein expression, without affecting either the expression of Tyk2 and Jak1 or the SOCS3 induction in response to IFN-α. These results show that IFN-α antagonizes STAT3 and SOCS3 signaling triggered by HCV and that STAT3 regulation correlates inversely with SOCS3 induction by IFN-α, which may be important in better understanding the complex interplay between IFN-α and signal molecules during HCV infection. PMID:26945996

  8. Structure of the mouse Stat 3/5 locus: evolution from Drosophila to zebrafish to mouse.

    Science.gov (United States)

    Miyoshi, K; Cui, Y; Riedlinger, G; Robinson, P; Lehoczky, J; Zon, L; Oka, T; Dewar, K; Hennighausen, L

    2001-01-15

    Signal transducers and activators of transcription (Stat) are transcription factors that can be activated by many cytokines. While Drosophila contains only one Stat (d-Stat), mammals contain seven, with STATs 3, 5a, and 5b being the closest functional relatives. To understand the evolutionary relationship between d-Stat and vertebrate STATs 3 and 5, we isolated, sequenced, and analyzed the zebrafish Stat3 (z-Stat3) gene and a 500-kb region spanning mouse chromosome 11, 60.5 cM containing three Stat genes (m-Stats). Within this region we identified the genes encoding m-Stats 3, 5a, and 5b, Cnp1, Hcrt/Orexin, Ptrf, GCN5, mDj11, and four new genes. The 5' ends of the m-Stat5a and m-Stat5b genes are juxtaposed to each other, and the 3' ends of the m-Stat3 and Stat5a genes face each other. While the m-Stat5a and m-Stat3 genes have one promoter each, which are active in many tissues, the m-Stat5b gene acquired two distinct promoters. The distal promoter is expressed ubiquitously, and transcription from the proximal promoter is restricted to liver, muscle, and mammary tissue. Through a comparison of exon-intron boundaries from the m-Stat3, m-Stat5a, and m-Stat5b, z-Stat3, and d-Stat genes, we deduced their evolutionary relationship. We propose that the Stat3 and Stat5 lineages are derived from the duplication of a common primordial gene and that d-Stat is a part of the Stat5 lineage. PMID:11161808

  9. Conditional overexpression of Stat3alpha in differentiating myeloid cells results in neutrophil expansion and induces a distinct, antiapoptotic and pro-oncogenic gene expression pattern.

    Science.gov (United States)

    Redell, Michele S; Tsimelzon, Anna; Hilsenbeck, Susan G; Tweardy, David J

    2007-10-01

    Normal neutrophil development requires G-CSF signaling, which includes activation of Stat3. Studies of G-CSF-mediated Stat3 signaling in cell culture and transgenic mice have yielded conflicting data regarding the role of Stat3 in myelopoiesis. The specific functions of Stat3 remain unclear, in part, because two isoforms, Stat3alpha and Stat3beta, are expressed in myeloid cells. To understand the contribution of each Stat3 isoform to myelopoiesis, we conditionally overexpressed Stat3alpha or Stat3beta in the murine myeloid cell line 32Dcl3 (32D) and examined the consequences of overexpression on cell survival and differentiation. 32D cells induced to overexpress Stat3alpha, but not Stat3beta, generated a markedly higher number of neutrophils in response to G-CSF. This effect was a result of decreased apoptosis but not of increased proliferation. Comparison of gene expression profiles of G-CSF-stimulated, Stat3alpha-overexpressing 32D cells with those of cells with normal Stat3alpha expression revealed novel Stat3 gene targets, which may contribute to neutrophil expansion and improved survival, most notably Slc28a2, a purine nucleoside transporter, which is critical for maintenance of intracellular nucleotide levels and prevention of apoptosis, and Gpr65, an acid-sensing, G protein-coupled receptor with pro-oncogenic and antiapoptotic functions. PMID:17634277

  10. The consequences of selective inhibition of signal transducer and activator of transcription 3 (STAT3) tyrosine705 phosphorylation by phosphopeptide mimetic prodrugs targeting the Src homology 2 (SH2) domain.

    Science.gov (United States)

    McMurray, John S; Mandal, Pijus K; Liao, Warren S; Klostergaard, Jim; Robertson, Fredika M

    2012-10-01

    Herein we review our progress on the development of phosphopeptide-based prodrugs targeting the SH2 domain of STAT3 to prevent recruitment to cytokine and growth factor receptors, activation, nuclear translocation and transcription of genes involved in cancer. We developed high affinity phosphopeptides (K I = 46-200 nM). Corresponding prodrugs inhibited constitutive and IL-6 induced Tyr705 phosphorylation at 0.5-1 μM in a variety of human cancer cell lines. They were not cytotoxic at 5 μM in vitro but they inhibited tumor growth in a human xenograft breast cancer model in mice, accompanied by reduced VEGF expression and angiogenesis. PMID:24058783

  11. 非小细胞肺癌中p-STAT3与Ki67的表达及意义%The expression and significance of phosphorylated signal transducer and activator of transcription 3 and Ki67 in non-small cell lung cancer

    Institute of Scientific and Technical Information of China (English)

    刘培杰

    2010-01-01

    Objective To study the expressions of phosphorylated signal transducer and activator of transcription 3(p-STAT3)and Ki67 in non-small cell lung cancer and their significance in tumor development and progression. Methods The expression of p-STAT3 and Ki67 were detected in 67 lung carcinoma tissues and 41 normal lung tissues by immun histochemical method. Results The positive rate of p-STAT3 in non-small cell lung cancer (67.16%,45/67) was significantly higher than that in normal lung tissue(17.07%,7/41). The positive rate of Ki67 in non-small cell lung cancer (76.12%,51/67) was significantly higher than that in normal lung tissue(7.31%,3/41).The expression of p-STAT3 and Ki67 were associated with clinical stages, lymph node transferation and histological grades(P<0.05). The expression of p-STAT3 and Ki67 were not associated with ages, sex, tumor location or size.The expression of p-STAT3 was positively correlated with Ki67 expression. Conclusions Abnormal activation of p-STAT3, can lead to excessive proliferation of tumor cells and Ki67 is a favorable indicator of proliferation of lung tumor cells, and the combined detection of p-STAT3 and Ki67 may be valuable for diagnosis and treatment of non-small cell lung cancer.%目的 研究磷酸化信号转导与转录活化因子3(p-STAT3)和 Ki67在非小细胞肺癌(NSCLC)发生、发展中的作用及相互关系.方法 采用免疫组织化学S-P法检测67例非小细胞肺癌组织和41例正常肺组织中p-STAT3与Ki67的表达.结果 非小细胞肺癌组织中p-STAT3的阳性表达率(67.16%,45/67)显著高于正常肺组织(17.07%,7/41),Ki67在非小细胞肺癌组织中的表达(76.12%,51/67)高于正常肺组织(7.31%,3/41).p-STAT3和 Ki67的表达与临床分期、有无淋巴转移和分化程度相关(P均<0.05),与患者年龄、性别、肿瘤位置及大小无关.p-STAT3的表达与Ki67表达呈正相关.结论 p-STAT3的异常活化可促进恶性肿瘤细胞的过度增殖,Ki67较好的反应了肺癌

  12. 雌激素活化GPER介导的IL-6/STAT3通路促进乳腺癌细胞SKBR-3增殖作用%Estrogen activates GPER mediated IL-6/STAT3 signaling pathway to enhance proliferation in breast cancer SKBR-3 cells

    Institute of Scientific and Technical Information of China (English)

    王健; 徐杰; 安雪青; 吕健东

    2015-01-01

    目的 探讨雌激素活化膜性雌激素受体(G-protein coupled estrogen receptor,GPER)所介导的IL-6/STAT3炎症信号通路对乳腺癌SKBR-3细胞增殖能力的影响.方法 用17-β雌二醇(E2)、GPER特异性激动剂(G1)、GPER特异性拮抗剂(G15)、IL-6中和抗体(Anti-IL-6)及STAT3特异性抑制剂JSI-124(cucurbitacin I)药物处理SKBR-3细胞后,分别得到对照组、E2处理组、G1处理组、E2+G15处理组、G1+G15处理组、E2+ Anti-IL-6处理组、G1+Anti-IL-6处理组、E2+ JSI-124处理组与G1+JSI-124处理组,用ELISA检测细胞培养液上清中IL-6的分泌量,CCK-8法检测细胞增殖能力的变化,Westernblot检测细胞中p-STAT3STAT3的蛋白表达水平.结果 E2和G1显著促进SKBR-3细胞上清中IL-6的分泌量,G15可显著阻断其分泌(P<0.05).E2及G1药物处理细胞后增殖能力较对照组显著增强,相对细胞数分别为对照组的(1.68±0.13)倍与(1.74±0.21)倍,其促增殖作用被G15及IL-6中和抗体(Anti-IL-6)显著抑制(P<0.05).E2及G1在不同时间点(1、3、6、12 h)均可显著促进细胞中p-STAT3的蛋白表达量,分别于12 h和3h达到表达峰值,其蛋白相对表达量分别为对照组的(2.54±0.23)倍和(3.12±0.24)倍.G15、Anti-IL-6及JSI-124显著阻断以上变化(P<0.05).JSI-124亦可明显抑制E2及G1所引起的促增殖效应(P<0.05).结论 雌激素活化膜性雌激素受体GPER促进乳腺癌SKBR-3细胞自分泌IL-6从而激活细胞中下游STAT3炎症信号通路,同时,GPER/IL-6/STAT3信号通路也介导了雌激素对细胞的增殖作用.

  13. STAT3: A Novel Molecular Mediator of Resistance to Chemoradiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Spitzner, Melanie, E-mail: melanie.spitzner@med.uni-goettingen.de [Department of General, Visceral and Pediatric Surgery, University Medicine Göttingen, Robert-Koch-Str. 40, Göttingen 37075 (Germany); Ebner, Reinhard [Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892 (United States); Wolff, Hendrik A. [Department of Radiotherapy and Radiooncology, University Medicine Göttingen, Robert-Koch-Str. 40, Göttingen 37075 (Germany); Ghadimi, B. Michael [Department of General, Visceral and Pediatric Surgery, University Medicine Göttingen, Robert-Koch-Str. 40, Göttingen 37075 (Germany); Wienands, Jürgen [Department of Cellular and Molecular Immunology, University Medicine Göttingen, Humboldtallee 34, Göttingen 37073 (Germany); Grade, Marian, E-mail: melanie.spitzner@med.uni-goettingen.de [Department of General, Visceral and Pediatric Surgery, University Medicine Göttingen, Robert-Koch-Str. 40, Göttingen 37075 (Germany)

    2014-09-29

    Chemoradiotherapy (CRT) represents a standard treatment for many human cancers, frequently combined with radical surgical resection. However, a considerable percentage of primary cancers are at least partially resistant to CRT, which represents a substantial clinical problem, because it exposes cancer patients to the potential side effects of both irradiation and chemotherapy. It is therefore exceedingly important to determine the molecular characteristics underlying CRT-resistance and to identify novel molecular targets that can be manipulated to re-sensitize resistant tumors to CRT. In this review, we highlight much of the recent evidence suggesting that the signal transducer and activator of transcription 3 (STAT3) plays a prominent role in mediating CRT-resistance, and we outline why inhibition of STAT3 holds great promise for future multimodal treatment concepts in oncology.

  14. The Role of STAT3 in Thyroid Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Sosonkina, Nadiya; Starenki, Dmytro; Park, Jong-In, E-mail: jipark@mcw.edu [Department of Biochemistry, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226 (United States)

    2014-03-06

    Thyroid cancer is the most common endocrine malignancy and its global incidence rates are rapidly increasing. Although the mortality of thyroid cancer is relatively low, its rate of recurrence or persistence is relatively high, contributing to incurability and morbidity of the disease. Thyroid cancer is mainly treated by surgery and radioiodine remnant ablation, which is effective only for non-metastasized primary tumors. Therefore, better understanding of the molecular targets available in this tumor is necessary. Similarly to many other tumor types, oncogenic molecular alterations in thyroid epithelium include aberrant signal transduction of the mitogen-activated protein kinase, phosphatidylinositol 3-kinase/AKT (also known as protein kinase B), NF-κB, and WNT/β-catenin pathways. However, the role of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT3) pathway, a well-known mediator of tumorigenesis in different tumor types, is relatively less understood in thyroid cancer. Intriguingly, recent studies have demonstrated that, in thyroid cancer, the JAK/STAT3 pathway may function in the context of tumor suppression rather than promoting tumorigenesis. In this review, we provide an update of STAT3 function in thyroid cancer and discuss some of the evidences that support this hypothesis.

  15. The Role of STAT3 in Thyroid Cancer

    International Nuclear Information System (INIS)

    Thyroid cancer is the most common endocrine malignancy and its global incidence rates are rapidly increasing. Although the mortality of thyroid cancer is relatively low, its rate of recurrence or persistence is relatively high, contributing to incurability and morbidity of the disease. Thyroid cancer is mainly treated by surgery and radioiodine remnant ablation, which is effective only for non-metastasized primary tumors. Therefore, better understanding of the molecular targets available in this tumor is necessary. Similarly to many other tumor types, oncogenic molecular alterations in thyroid epithelium include aberrant signal transduction of the mitogen-activated protein kinase, phosphatidylinositol 3-kinase/AKT (also known as protein kinase B), NF-κB, and WNT/β-catenin pathways. However, the role of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT3) pathway, a well-known mediator of tumorigenesis in different tumor types, is relatively less understood in thyroid cancer. Intriguingly, recent studies have demonstrated that, in thyroid cancer, the JAK/STAT3 pathway may function in the context of tumor suppression rather than promoting tumorigenesis. In this review, we provide an update of STAT3 function in thyroid cancer and discuss some of the evidences that support this hypothesis

  16. CRITICAL ROLE OF STAT3 IN IL-6-MEDIATED DRUG RESISTANCE IN HUMAN NEUROBLASTOMA

    OpenAIRE

    Ara, Tasnim; Nakata, Rie; Sheard, Michael A.; Shimada, Hiroyuki; Buettner, Ralf; Groshen, Susan G.; Ji, Lingyun; Yu, Hua; Jove, Richard; Seeger, Robert C.; DeClerck, Yves A

    2013-01-01

    Drug resistance is a major cause of treatment failure in cancer. Here we have evaluated the role of STAT3 in environment-mediated drug resistance (EMDR) in human neuroblastoma. We determined that STAT3 was not constitutively active in most neuroblastoma cell lines but was rapidly activated upon treatment with interleukin-6 (IL-6) alone and in combination with the soluble IL-6 receptor (sIL-6R). Treatment of neuroblastoma cells with IL-6 protected them from drug-induced apoptosis in a STAT3-de...

  17. EFFECT OF STAT3 SPECIFIC SHRNA EXPRESSION VECTOR ON PROLIFERATION AND APOPTOSIS OF HUMAN PANCREATIC CANCER CELLS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To construct signal transduction and activators of transcription 3 (STAT3) short hairpin RNA (shRNA) expression vector and to investigate its inhibitory effects on STAT3 expression, cell proliferation and apoptosis of human pancreatic cancer. Methods Three pairs of hairpin-like oligonucleotide sequences specific for human STAT3 gene were designed and synthesized. The annealed oligonucleotide fragments were subcloned into pRNAT-U6.1/Neo plasmid. The STAT3 shRNA expressing vectors were confirmed by PCR and DNA sequencing. STAT3 mRNA and protein expression were examined by using reverse transcription polymerase chain reaction (RT-PCR) and Western blot, respectively. MTT assay and flow cytometry were performed to detect the state of cell proliferation and cell apoptosis, respectively. Results PCR and DNA sequencing showed that the oligonucleotide fragments were correctly inserted into pRNAT-U6.1/Neo plasmid. STAT3 expression and cell proliferation in the transfected cells was inhibited significantly by three STAT3 shRNA expressing vectors (P<0.05). ConclusionSTAT3 shRNA expression vector can effectively inhibit the expression of STAT3. Silencing of STAT3 with RNAi can significantly inhibit the proliferation and promotes the apoptosis of pancreatic cancer cells and may provide a novel therapeutic target for treating pancreatic cancer.

  18. Down-regulation of STAT3 expression by vector-based small interfering RNA inhibits pancreatic cancer growth

    Institute of Scientific and Technical Information of China (English)

    Chen Huang; Guang Yang; Tao Jiang; Jun Cao; Ke-Jian Huang; Zheng-Jun Qiu

    2011-01-01

    AIM: To evaluate the effect of RNA interference (RNAi) mediated silence of signal transduction and activation of transcription (STAT)3 on the growth of human pancreatic cancer cells both in vitro and in vivo . METHODS: STAT3 specific shRNA was used to silence the expression of STAT3 in pancreatic cancer cell line SW1990. The anti-growth effects of RNAi against STAT3 were studied in vitro and in experimental cancer xenografts in nude mice. The potential pathways involved in STAT3 signaling were detected using reverse transcription polymerase chain reaction and western blotting. RESULTS: The expression of the STAT3 was inhibited using RNAi in SW1990 cells. RNAi against STAT3 inhibited cell proliferation, induced cell apoptosis and significantly reduced the levels of CyclinD1 and Bcl-xL when compared with parental and control vector-transfected cells. In vivo experiments showed that RNAi against STAT3 inhibited the tumorigenicity of SW1990 cells and significantly suppressed tumor growth when it was directly injected into tumors. CONCLUSION: STAT3 signaling pathway plays an important role in the progression of pancreatic cancer, and silence of STAT3 gene using RNAi technique may be a novel therapeutic option for treatment of pancreatic cancer.

  19. Insertional Mutagenesis Identifies a STAT3/Arid1b/β-catenin Pathway Driving Neurofibroma Initiation

    Directory of Open Access Journals (Sweden)

    Jianqiang Wu

    2016-03-01

    Full Text Available To identify genes and signaling pathways that initiate Neurofibromatosis type 1 (NF1 neurofibromas, we used unbiased insertional mutagenesis screening, mouse models, and molecular analyses. We mapped an Nf1-Stat3-Arid1b/β-catenin pathway that becomes active in the context of Nf1 loss. Genetic deletion of Stat3 in Schwann cell progenitors (SCPs and Schwann cells (SCs prevents neurofibroma formation, decreasing SCP self-renewal and β-catenin activity. β-catenin expression rescues effects of Stat3 loss in SCPs. Importantly, P-STAT3 and β-catenin expression correlate in human neurofibromas. Mechanistically, P-Stat3 represses Gsk3β and the SWI/SNF gene Arid1b to increase β-catenin. Knockdown of Arid1b or Gsk3β in Stat3fl/fl;Nf1fl/fl;DhhCre SCPs rescues neurofibroma formation after in vivo transplantation. Stat3 represses Arid1b through histone modification in a Brg1-dependent manner, indicating that epigenetic modification plays a role in early tumorigenesis. Our data map a neural tumorigenesis pathway and support testing JAK/STAT and Wnt/β-catenin pathway inhibitors in neurofibroma therapeutic trials.

  20. Insertional Mutagenesis Identifies a STAT3/Arid1b/β-catenin Pathway Driving Neurofibroma Initiation.

    Science.gov (United States)

    Wu, Jianqiang; Keng, Vincent W; Patmore, Deanna M; Kendall, Jed J; Patel, Ami V; Jousma, Edwin; Jessen, Walter J; Choi, Kwangmin; Tschida, Barbara R; Silverstein, Kevin A T; Fan, Danhua; Schwartz, Eric B; Fuchs, James R; Zou, Yuanshu; Kim, Mi-Ok; Dombi, Eva; Levy, David E; Huang, Gang; Cancelas, Jose A; Stemmer-Rachamimov, Anat O; Spinner, Robert J; Largaespada, David A; Ratner, Nancy

    2016-03-01

    To identify genes and signaling pathways that initiate Neurofibromatosis type 1 (NF1) neurofibromas, we used unbiased insertional mutagenesis screening, mouse models, and molecular analyses. We mapped an Nf1-Stat3-Arid1b/β-catenin pathway that becomes active in the context of Nf1 loss. Genetic deletion of Stat3 in Schwann cell progenitors (SCPs) and Schwann cells (SCs) prevents neurofibroma formation, decreasing SCP self-renewal and β-catenin activity. β-catenin expression rescues effects of Stat3 loss in SCPs. Importantly, P-STAT3 and β-catenin expression correlate in human neurofibromas. Mechanistically, P-Stat3 represses Gsk3β and the SWI/SNF gene Arid1b to increase β-catenin. Knockdown of Arid1b or Gsk3β in Stat3(fl/fl);Nf1(fl/fl);DhhCre SCPs rescues neurofibroma formation after in vivo transplantation. Stat3 represses Arid1b through histone modification in a Brg1-dependent manner, indicating that epigenetic modification plays a role in early tumorigenesis. Our data map a neural tumorigenesis pathway and support testing JAK/STAT and Wnt/β-catenin pathway inhibitors in neurofibroma therapeutic trials. PMID:26904939

  1. STAT3 signaling controls satellite cell expansion and skeletal muscle repair

    Science.gov (United States)

    Tierney, Matthew Timothy; Aydogdu, Tufan; Sala, David; Malecova, Barbora; Gatto, Sole; Puri, Pier Lorenzo; Latella, Lucia; Sacco, Alessandra

    2015-01-01

    The progression of disease- and age-dependent skeletal muscle wasting results in part from a decline in the number and function of satellite cells, the direct cellular contributors to muscle repair1–10. However, little is known about the molecular effectors underlying satellite cell impairment and depletion. Elevated levels of inflammatory cytokines, including interleukin-6 (IL-6), are associated with both age-related and muscle-wasting conditions11–13. The levels of STAT3, a downstream effector of IL-6, are also elevated with muscle wasting14,15, and STAT3 has been implicated in the regulation of self-renewal and stem cell fate in several tissues16–19. Here we show that IL-6–activated Stat3 signaling regulates satellite cell behavior, promoting myogenic lineage progression through myogenic differentiation 1 (Myod1) regulation. Conditional ablation of Stat3 in Pax7-expressing satellite cells resulted in their increased expansion during regeneration, but compromised myogenic differentiation prevented the contribution of these cells to regenerating myofibers. In contrast, transient Stat3 inhibition promoted satellite cell expansion and enhanced tissue repair in both aged and dystrophic muscle. The effects of STAT3 inhibition were conserved in human myoblasts. The results of this study indicate that pharmacological manipulation of STAT3 activity can be used to counteract the functional exhaustion of satellite cells, thereby maintaining the endogenous regenerative response and ameliorating muscle-wasting diseases. PMID:25194572

  2. Role of STAT3 in transformation and drug resistance in CML

    Directory of Open Access Journals (Sweden)

    Rajesh R Nair

    2012-04-01

    Full Text Available Chronic Myeloid Leukemia (CML is initially driven by the bcr-abl fusion oncoprotein. The identification of bcr-abl led to the discovery and rapid translation into the clinic of bcr-abl kinase inhibitors. Although, bcr-abl inhibitors are efficacious, experimental evidence indicates that targeting bcr-abl is not sufficient for elimination of minimal residual disease found within the bone marrow (BM. Experimental evidence indicates that the failure to eliminate the leukemic stem cell contributes to persistent minimal residual disease. Thus curative strategies will likely need to focus on strategies where bcr-abl inhibitors are given in combination with agents that specifically target the leukemic stem cell or the leukemic stem cell niche. One potential target to be exploited is the JAK/STAT3 pathway. Recently using STAT3 conditional knock-out mice it was shown that STAT3 is critical for initiating the disease. Interestingly, in the absence of treatment, STAT3 was not shown to be required for maintenance of the disease, suggesting that STAT3 is required only in the tumor initiating stem cell population (Hoelbl et al., 2010. In the context of the BM microenvironment, STAT3 is activated in a bcr-abl independent manner by the cytokine milieu. Activation of JAK/STAT3 was shown to contribute to cell survival even in the event of complete inhibition of bcr-abl activity within the BM compartment. Taken together, these studies suggest that JAK/STAT3 is an attractive therapeutic target for developing strategies for targeting the JAK-STAT3 pathway in combination with bcr-abl kinase inhibitors and may represent a viable strategy for eliminating or reducing minimal residual disease located in the bone marrow in CML.

  3. Dancing rhinos in stilettos: The amazing saga of the genomic and nongenomic actions of STAT3 in the heart.

    Science.gov (United States)

    Zouein, Fouad A; Kurdi, Mazen; Booz, George W

    2013-07-01

    A substantial body of evidence has shown that signal transducer and activator of transcription 3 (STAT3) has an important role in the heart in protecting the myocardium from ischemia and oxidative stress. These actions are attributed to STAT3 functioning as a transcription factor in upregulating cardioprotective genes. Loss of STAT3 has been implicated as well in the pathogenesis of heart failure and, in that context and in addition to the loss of a cardioprotective gene program, nuclear STAT3 has been identified as a transcriptional repressor important for the normal functioning of the ubiquitin-proteasome system for protein degradation. The later finding establishes a genomic role for STAT3 in controlling cellular homeostasis in cardiac myocytes independent of stress. Surprisingly, although a well-studied area, very few downstream gene targets of STAT3 in the heart have been definitively identified. In addition, STAT3 is now known to induce gene expression by noncanonical means that are not well characterized in the heart. On the other hand, recent evidence has shown that STAT3 has important nongenomic actions in cardiac myocytes that affect microtubule stability, mitochondrial respiration, and autophagy. These extranuclear actions of STAT3 involve protein-protein interactions that are incompletely understood, as is their regulation in both the healthy and injured heart. Moreover, how the diverse genomic and nongenomic actions of STAT3 crosstalk with each other is unchartered territory. Here we present an overview of what is and is not known about both the genomic and nongenomic actions of STAT3 in the heart from a structure-function perspective that focuses on the impact of posttranslational modifications and oxidative stress in regulating the actions and interactions of STAT3. Even though we have learnt a great deal about the role played by STAT3 in the heart, much more awaits to be discovered. PMID:24069556

  4. Pivotal importance of STAT3 in protecting the heart from acute and chronic stress: new advancement and unresolved issues

    Directory of Open Access Journals (Sweden)

    Foaud A. Zouein

    2015-11-01

    Full Text Available The transcription factor Signal Transducer and Activator of Transcription 3 (STAT3 has been implicated in protecting the heart from acute ischemic injury under both basal conditions and as a crucial component of pre- and post-conditioning protocols. A number of anti-oxidant and antiapoptotic genes are upregulated by STAT3 via canonical means involving phosphorylation on Y705 and S727, although other incompletely defined posttranslational modifications are involved. In addition, STAT3 is now known to be present in cardiac mitochondria and to exert actions that regulate the electron transport chain, reactive oxygen species (ROS production, and mitochondrial permeability transition pore (mPTP opening. These non-canonical actions of STAT3 are enhanced by S727 phosphorylation. The molecular basis for the mitochondrial actions of STAT3 are poorly understood, but STAT3 is known to interact with a critical subunit of complex I and to regulate complex I function. Dysfunctional complex I has been implicated in ischemic injury, heart failure, and the aging process. Evidence also indicates that STAT3 is protective to the heart under chronic stress conditions, including hypertension, pregnancy, and advanced age. Paradoxically, the accumulation of unphosphorylated STAT3 (U-STAT3 in the nucleus has been suggested to drive pathological cardiac hypertrophy and inflammation via noncanonical gene expression, perhaps involving a distinct acetylation profile. U-STAT3 may also regulate chromatin stability. Our understanding of how the noncanonical genomic and mitochondrial actions of STAT3 in the heart are regulated and coordinated with the canonical actions of STAT3 is rudimentary. Here we present an overview of what is currently known about the pleotropic actions of STAT3 in the heart in order to highlight controversies and unresolved issues.

  5. Stat3 Programs Th17-Specific Regulatory T Cells to Control GN

    Science.gov (United States)

    Kluger, Malte A.; Luig, Michael; Wegscheid, Claudia; Goerke, Boeren; Paust, Hans-Joachim; Brix, Silke R.; Yan, Isabell; Mittrücker, Hans-Willi; Hagl, Beate; Renner, Ellen D.; Tiegs, Gisa; Wiech, Thorsten; Stahl, Rolf A.K.; Panzer, Ulf

    2014-01-01

    A pathogenic role for Th17 cells in inflammatory renal disease is well established. The mechanisms underlying their counter-regulation are, however, largely unknown. Recently, Th17 lineage-specific regulatory T cells (Treg17) that depend on activation of the transcription factor Stat3 were identified. We studied the function of Treg17 in the nephrotoxic nephritis (NTN) model of crescentic GN. The absence of Treg17 cells in Foxp3Cre×Stat3fl/fl mice resulted in the aggravation of NTN and skewing of renal and systemic immune responses toward Th17. Detailed analysis of Stat3-deficient Tregs revealed that the survival, activation, proliferation, and suppressive function of these cells remained intact. However, Tregs from Foxp3Cre×Stat3fl/fl mice lacked surface expression of the chemokine receptor CCR6, which resulted in impaired renal trafficking. Furthermore, aggravation of NTN was reversible in the absence of Th17 responses, as shown in CD4Cre×Stat3fl/fl mice lacking both Treg17 and Th17 cells, suggesting that Th17 cells are indeed the major target of Treg17 cells. Notably, immunohistochemistry revealed CCR6-bearing Treg17 cells in kidney biopsy specimens of patients with GN. CCR6 expression on human Treg17 cells also appears dependent on STAT3, as shown by analysis of Tregs from patients with dominant-negative STAT3 mutations. Our data indicate the presence and involvement of Stat3/STAT3-dependent Treg17 cells that specifically target Th17 cells in murine and human crescentic GN, and suggest the kidney-specific action of these Treg17 cells is regulated by CCR6-directed migration into areas of Th17 inflammation. PMID:24511136

  6. Role of unphosphorylated transcription factor STAT3 in late cerebral ischemia after subarachnoid hemorrhage

    DEFF Research Database (Denmark)

    Samraj, Ajoy K; Müller, Anne H; Grell, Anne-Sofie;

    2014-01-01

    Molecular mechanisms behind increased cerebral vasospasm and local inflammation in late cerebral ischemia after subarachnoid hemorrhage (SAH) are poorly elucidated. Using system biology tools and experimental SAH models, we have identified signal transducer and activator of transcription 3 (STAT3...

  7. STAT3 modulation to enhance motor neuron differentiation in human neural stem cells.

    Directory of Open Access Journals (Sweden)

    Rajalaxmi Natarajan

    Full Text Available Spinal cord injury or amyotrophic lateral sclerosis damages spinal motor neurons and forms a glial scar, which prevents neural regeneration. Signal transducer and activator of transcription 3 (STAT3 plays a critical role in astrogliogenesis and scar formation, and thus a fine modulation of STAT3 signaling may help to control the excessive gliogenic environment and enhance neural repair. The objective of this study was to determine the effect of STAT3 inhibition on human neural stem cells (hNSCs. In vitro hNSCs primed with fibroblast growth factor 2 (FGF2 exhibited a lower level of phosphorylated STAT3 than cells primed by epidermal growth factor (EGF, which correlated with a higher number of motor neurons differentiated from FGF2-primed hNSCs. Treatment with STAT3 inhibitors, Stattic and Niclosamide, enhanced motor neuron differentiation only in FGF2-primed hNSCs, as shown by increased homeobox gene Hb9 mRNA levels as well as HB9+ and microtubule-associated protein 2 (MAP2+ co-labeled cells. The increased motor neuron differentiation was accompanied by a decrease in the number of glial fibrillary acidic protein (GFAP-positive astrocytes. Interestingly, Stattic and Niclosamide did not affect the level of STAT3 phosphorylation; rather, they perturbed the nuclear translocation of phosphorylated STAT3. In summary, we demonstrate that FGF2 is required for motor neuron differentiation from hNSCs and that inhibition of STAT3 further increases motor neuron differentiation at the expense of astrogliogenesis. Our study thus suggests a potential benefit of targeting the STAT3 pathway for neurotrauma or neurodegenerative diseases.

  8. MicroRNA-124 suppresses growth of human hepatocellular carcinoma by targeting STAT3

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yanxin [Department of Neurobiology, Neuroscience Research Institute, Peking University Health Science Center, Beijing 100191 (China); Biomedical Research Institute, Shenzhen-PKU-HKUST Medical Center, Guangdong Province, Shenzhen 518036 (China); Yue, Xupeng [Biomedical Research Institute, Shenzhen-PKU-HKUST Medical Center, Guangdong Province, Shenzhen 518036 (China); Cui, Yuanyuan [Department of Neurobiology, Neuroscience Research Institute, Peking University Health Science Center, Beijing 100191 (China); Zhang, Jufeng, E-mail: jfzhang111@163.com [Biomedical Research Institute, Shenzhen-PKU-HKUST Medical Center, Guangdong Province, Shenzhen 518036 (China); Wang, KeWei, E-mail: wangkw@bjmu.edu.cn [Department of Neurobiology, Neuroscience Research Institute, Peking University Health Science Center, Beijing 100191 (China); Biomedical Research Institute, Shenzhen-PKU-HKUST Medical Center, Guangdong Province, Shenzhen 518036 (China); Department of Molecular and Cellular Pharmacology, State Key Laboratory of Natural and Biomimetic Drugs, Peking University School of Pharmaceutical Sciences, Beijing 100191 (China)

    2013-11-29

    Highlights: •miR-124 is down-regulated in hepatocellular carcinoma HepG2 cells. •Over-expression of miR-124 suppresses proliferation and induces apoptosis in HepG2 cells. •miR-124 inhibits xenograft tumor growth in nude mice implanted with HepG2 cells by reducing STAT3 expression. •STATs function as a novel target of miR-124 in HCC HepG2 cells. -- Abstract: The aberrant expression of microRNAs is associated with development and progression of cancers. Down-regulation of miR-124 has been demonstrated in the hepatocellular carcinoma (HCC), but the underlying mechanism by which miR-124 suppresses tumorigenesis in HCC remains elusive. In this study, we found that miR-124 suppresses the tumor growth of HCC through targeting the signal transducers and activators of transcription 3 (STAT3). Overexpression of miR-124 suppressed proliferation and induced apoptosis in HepG-2 cells. Luciferase assay confirmed that miR-124 binding to the 3′-UTR region of STAT3 inhibited the expression of STAT3 and phosphorylated STAT3 proteins in HepG-2 cells. Knockdown of STAT3 by siRNA in HepG-2 cells mimicked the effect induced by miR-124. Overexpression of STAT3 in miR-124-transfected HepG-2 cells effectively rescued the inhibition of cell proliferation caused by miR-124. Furthermore, miR-124 suppressed xenograft tumor growth in nude mice implanted with HepG-2 cells by reducing STAT3 expression. Taken together, our findings show that miR-124 functions as tumor suppressor in HCC by targeting STAT3, and miR-124 may therefore serve as a biomarker for diagnosis and therapeutics in HCC.

  9. Regulation of Natural Killer Cell Function by STAT3

    Directory of Open Access Journals (Sweden)

    Nicholas eCacalano

    2016-04-01

    Full Text Available Natural killer (NK cells, key members of a distinct hempatopoietic lineage, innate lymphoid cells (ILCs, are critical effectors that mediate cytotoxicity toward tumor and virally-infected cells but also regulate inflammation, antigen presentation and the adaptive immune response. It has been shown that NK cells can regulate the development and activation of many other components of the immune response such as dendritic cells, which in turn, modulate the function of NK cells in multiple synergistic feed back loops driven by cell-cell contact and the secretion of cytokines and chemokines that control effector function and migration of cells to sites of immune activation. The Signal Transducer and Activator of Transcription (STAT-3 is involved in driving almost all of the pathways that control NK cytolytic activity as well as the reciprocal regulatory interactions between NK cells and other components of the immune system. In the context of tumor immunology, NK cells are a first line of defense that eliminates pre-cancerous and transformed cells early in the process of carcinogenesis, through a mechanism of immune surveillance. Even after tumors become established, NK cells are critical components of anti-cancer immunity: dysfunctional NK cells are often found in the peripheral blood of cancer patients and the lack of NK cells in the tumor microenvironment often correlates with poor prognosis. The pathways and soluble factors activated in tumor-associated NK cells, cancer cells, and regulatory myeloid cells which determine the outcome of cancer immunity are all critically regulated by STAT3. Using the tumor microenvironment as a paradigm, we present here an overview of the research that has revealed fundamental mechanisms through which STAT3 regulates all aspects of natural killer cell biology, including NK development, activation, target cell killing, and fine tuning of the innate and adaptive immune responses.

  10. Sorafenib inhibits growth and metastasis of hepatocellular carcinoma by blocking STAT3

    Institute of Scientific and Technical Information of China (English)

    Fang-Ming Gu; Quan-Lin Li; Qiang Gao; Jia-Hao Jiang; Xiao-Yong Huang; Jin-Feng Pan; Jia Fan; Jian Zhou

    2011-01-01

    AIM: To investigate the inhibitory role and the underlying mechanisms of sorafenib on signal transducer and activator of transcription 3 (STAT3) activity in hepatocellular carcinoma (HCC). METHODS: Human and rat HCC cell lines were treated with sorafenib. Proliferation and STAT3 dephosphorylation were assessed. Potential molecular mechanisms of STAT3 pathway inhibition by sorafenib were evaluated. In vivo antitumor action and STAT3 inhibition were investigated in an immunocompetent orthotopic rat HCC model. RESULTS: Sorafenib decreased STAT3 phosphorylation at the tyrosine and serine residues (Y705 and S727), but did not affect Janus kinase 2 (JAK2) and phospha-tase shatterproof 2 (SHP2), which is associated with growth inhibition in HCC cells. Dephosphorylation of S727 was associated with attenuated extracellular signal-regulated kinase (ERK) phosphorylation, similar to the effects of a mitogen-activated protein kinase (MEK) inhibitor U0126, suggesting that sorafenib induced S727 dephosphorylation by inhibiting MEK/ERK signaling. Meanwhile, sorafenib could also inhibit Akt phosphorylation, and both the phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 and Akt knockdown resulted in Y705 dephosphorylation, indicating that Y705 dephosphorylation by sorafenib was mediated by inhibiting the PI3K/Akt pathway. Finally, in the rat HCC model, sorafenib significantly inhibited STAT3 activity, reducing tumor growth and metastasis. CONCLUSION: Sorafenib inhibits growth and metastasis of HCC in part by blocking the MEK/ERK/STAT3 and PI3K/Akt/STAT3 signaling pathways, but independent of JAK2 and SHP2 activation.

  11. Effect of combination of STAT3 RNAi and 60Co γ-irradiation on U251 cell proliferation

    International Nuclear Information System (INIS)

    Objective: To construct signal transduction and activators of transcription 3 (STAT3) small interference RNA (siRNA) expression vector and to study its effect on STAT3 expression and U251 cell line proliferation. Methods: STAT3 specific 19 bp oligonucleotides were designed and synthesized. These oligonucleotides were annealed to form the double strand DNA fragments and these fragments were cloned into Psilence2.1-U6-H1 vector. The recombinant of STAT3-siRNA expressing construction was confirmed by Hind III and BamH I double digestion and sequencing. The STAT3-siRNA was transfected into U251 cell. The inhibitory effect of STAT3-siRNA construction was tested by Western blot. Cellular proliferation activities were measured by tetrazolium bromide (MTT) colorimetry. Cloning efficiency and MTF were used to confirm the radiation dose. Results: STAT3-siRNA expression vector was successfully constructed, and it could effectively down-regulate the protein levels of STAT3 in transfected U251 cell line; and the radiation dose was confirmed to 2 Gy. U251 cells transfected with STAT3-siRNA expression vector showed lower cellular proliferation compared with non-transfected U251 cells (P60Co γ-irradiation showed lower cellular proliferation compared with non-irradiated U251 cells (P60Co γ irradiation can enhance the inhibitory efficiency. (authors)

  12. Nuclear translocation of phosphorylated STAT3 regulates VEGF-A-induced lymphatic endothelial cell migration and tube formation

    Energy Technology Data Exchange (ETDEWEB)

    Okazaki, Hideki; Tokumaru, Sho; Hanakawa, Yasushi; Shiraishi, Ken; Shirakata, Yuji; Dai, Xiuju; Yang, Lijun; Tohyama, Mikiko; Hashimoto, Koji [Department of Dermatology, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295 (Japan); Sayama, Koji, E-mail: sayama@m.ehime-u.ac.jp [Department of Dermatology, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295 (Japan)

    2011-09-02

    Highlights: {yields} VEGF-A enhanced lymphatic endothelial cell migration and increased tube formation. {yields} VEGF-A treated lymphatic endothelial cell showed activation of STAT3. {yields} Dominant-negative STAT3 inhibited VEGF-A-induced lymphatic endothelial cell migration and tube formation. -- Abstract: Vascular endothelial growth factor (VEGF) is an endothelial cell-specific growth factor that regulates endothelial functions, and signal transducers and activators of transcription (STATs) are known to be important during VEGF receptor signaling. The aim of this study was to determine whether STAT3 regulates VEGF-induced lymphatic endothelial cell (LEC) migration and tube formation. VEGF-A (33 ng/ml) enhanced LEC migration by 2-fold and increased tube length by 25% compared with the control, as analyzed using a Boyden chamber and Matrigel assay, respectively. Western blot analysis and immunostaining revealed that VEGF-A induced the nuclear translocation of phosphorylated STAT3 in LECs, and this translocation was blocked by the transfection of LECs with an adenovirus vector expressing a dominant-negative mutant of STAT3 (Ax-STAT3F). Transfection with Ax-STAT3F also almost completely inhibited VEGF-A-induced LEC migration and tube formation. These results indicate that STAT3 is essential for VEGF-A-induced LEC migration and tube formation and that STAT3 regulates LEC functions.

  13. Oncovirus Kaposi sarcoma herpesvirus (KSHV) represses tumor suppressor PDLIM2 to persistently activate nuclear factor κB (NF-κB) and STAT3 transcription factors for tumorigenesis and tumor maintenance.

    Science.gov (United States)

    Sun, Fan; Xiao, Yadong; Qu, Zhaoxia

    2015-03-20

    Kaposi sarcoma herpesvirus (KSHV) is the most common cause of malignancies among AIDS patients. However, how KSHV induces tumorigenesis remains largely unknown. Here, we demonstrate that one important mechanism underlying the tumorigenesis of KSHV is through transcriptional repression of the tumor suppressor gene PDZ-LIM domain-containing protein 2 (PDLIM2). PDLIM2 expression is repressed in KSHV-transformed human umbilical vascular endothelial cells as well as in KSHV-associated cancer cell lines and primary tumors. Importantly, PDLIM2 repression is essential for KSHV-induced persistent activation of nuclear factor κB (NF-κB) and signal transducer and activator of transcription 3 (STAT3) and subsequent tumorigenesis and tumor maintenance. Our mechanistic studies indicate that PDLIM2 repression by KSHV involves DNA methylation. Notably, the epigenetic repression of PDLIM2 can be reversed by 5-aza-2-deoxycytidine and vitamin D to suppress KSHV-associated cancer cell growth. These studies not only improve our understanding of KSHV pathogenesis but also provide immediate therapeutic strategies for KSHV-mediated cancers, particularly those associated with AIDS.

  14. Ablation of STAT3 in the B Cell Compartment Restricts Gammaherpesvirus Latency In Vivo

    Science.gov (United States)

    Reddy, Sandeep Steven; Foreman, Hui-Chen Chang; Sioux, Thubten Ozula; Park, Gee Ho; Poli, Valeria; Reich, Nancy C.

    2016-01-01

    ABSTRACT A challenging property of gammaherpesviruses is their ability to establish lifelong persistence. The establishment of latency in B cells is thought to involve active virus engagement of host signaling pathways. Pathogenic effects of these viruses during latency or following reactivation can be devastating to the host. Many cancers, including those associated with members of the gammaherpesvirus family, Kaposi’s sarcoma-associated herpesvirus and Epstein-Barr virus, express elevated levels of active host signal transducer and activator of transcription-3 (STAT3). STAT3 is activated by tyrosine phosphorylation in response to many cytokines and can orchestrate effector responses that include proliferation, inflammation, metastasis, and developmental programming. However, the contribution of STAT3 to gammaherpesvirus pathogenesis remains to be completely understood. This is the first study to have identified STAT3 as a critical host determinant of the ability of gammaherpesvirus to establish long-term latency in an animal model of disease. Following an acute infection, murine gammaherpesvirus 68 (MHV68) established latency in resident B cells, but establishment of latency was dramatically reduced in animals with a B cell-specific STAT3 deletion. The lack of STAT3 in B cells did not impair germinal center responses for immunoglobulin (Ig) class switching in the spleen and did not reduce either total or virus-specific IgG titers. Although ablation of STAT3 in B cells did not have a global effect on these assays of B cell function, it had long-term consequences for the viral load of the host, since virus latency was reduced at 6 to 8 weeks postinfection. Our findings establish host STAT3 as a mediator of gammaherpesvirus persistence. PMID:27486189

  15. Heat Shock Protein 72 Antagonizes STAT3 Signaling to Inhibit Fibroblast Accumulation in Renal Fibrogenesis.

    Science.gov (United States)

    Zhou, Yi; Cao, Shirong; Li, Huiyan; Peng, Xuan; Wang, Yating; Fan, Jinjin; Wang, Yihan; Zhuang, Shougang; Yu, Xueqing; Mao, Haiping

    2016-04-01

    Heat shock protein 72 (HSP72) has been shown to attenuate unilateral ureteral obstruction-induced kidney fibrosis. It remains unknown whether HSP72 has direct effects on fibroblast proliferation in the renal fibrotic evolution. Herein, we first confirmed that increased HSP72 expression occurred in fibrotic human kidneys. Using three different animal models of kidney fibrosis, pharmacological down-regulation or genetic deletion of endogenous HSP72 expression exacerbated STAT3 phosphorylation, fibroblast proliferation, and tubulointerstitial fibrosis. In contrast, treatment with geranylgeranyl acetone, a specific inducer of HSP72, reduced phosphorylated STAT3 and protected animals from kidney fibrosis. In cultured renal interstitial fibroblasts, overexpression of HSP72 blocked transforming growth factor (TGF)-β1-induced cell activation and proliferation, as evidenced by inhibiting expression of α-smooth muscle actin, fibronectin, and collagen I/III, as well as by reducing cell numbers and DNA synthesis. Mechanical studies showed that overexpressed HSP72 attenuated TGF-β-induced phosphorylation and nuclear translocation of STAT3 and its downstream protein expression. However, siRNA knockdown of HSP72 increased TGF-β-induced STAT3 activity and fibroblast proliferation. Ectopic expression of a constitutively active STAT3 conferred resistance to HSP72 inhibition of fibroblast proliferation. Thus, HSP72 blocks fibroblast activation and proliferation in renal fibrosis via targeting the STAT3 pathway and may serve as a novel therapeutic agent for chronic kidney disease regardless of the etiology. PMID:26851345

  16. EXPRESSIONS OF STAT3 AND MMP-2 IN CERVICAL CANCER%宫颈癌组织STAT3和MMP-2表达及意义

    Institute of Scientific and Technical Information of China (English)

    李晓蕾; 王霞; 周军红; 赵爱琳

    2011-01-01

    目的 探讨信号转导和转录激活因子3(STAT3)与基质金属蛋白酶-2(MMP-2)在宫颈癌组织表达及意义.方法 采用免疫组织化学SP法分别检测16例正常组织、50例宫颈上皮内瘤变(CIN)、50例宫颈癌组织中STAT3与MMP-2的表达水平.结果 正常宫颈、CIN及宫颈癌组织中STAT3、MMP-2表达水平逐渐增高,各组间差异均有统计学意义(x2=6.417~27.097,P<0.05).STAT3异常表达与宫颈癌的病理分级和临床分期及淋巴结转移有关(x2=4.778~13.651,P<0.05);MMP-2的异常表达与临床分期及淋巴结转移有关(x2=9.039、5.003,P<0.05),而与病理分级无关;两者与病人年龄、肿瘤大小及肿瘤类型均无相关性.宫颈癌组织STAT3与MMP-2的表达呈正相关(r=0.398,P<0.05).结论 宫颈癌组织STAT3与MMP-2表达密切相关,两者表达水平可能与宫颈癌浸润转移有关,STAT3可能通过调控其下游靶基因MMP-2的表达影响宫颈癌的浸润转移.%Objective To investigate the expressions of signal transduction and activators of transcription-3 (STAT3)and matrix metalloproteinase-2 (MMP-2) in cervical cancer and their significance. Methods Immunohistochemical technique was used to detect expressions of STAT3 and MMP-2 in samples of 16 normal cervical tissue, 50 cervical intraepithelial neoplasia (CIN)and 50 cervical cancer. Results The expressions of STAT3 and MMP-2 gradually increased in the order of normal cervical tissue, CIN, and cervical cancer, the differences between the three groups being statistically significant (x2 = 6.417-27.097, P<0.05). The expression of STAT3 was related to clinical stage and pathological grade and lymph node metastasis (x2 = 4.778-13.651,P<0.05) ; and that of MMP-2 was related to clinical stage and lymph node metastasis (x2 = 9.039,5. 003; P<0.05),while no relation to pathological grade. STAT3 and MMP-2 were positively correlated (r=0.398,P<0.05), but these two items were no correlation with patient's age

  17. Interleukin-2 induces tyrosine phosphorylation and nuclear translocation of stat3 in human T lymphocytes

    DEFF Research Database (Denmark)

    Nielsen, M; Svejgaard, A; Skov, S;

    1994-01-01

    stimulation through the IL-2R induced tyrosine phosphorylation and subsequent nuclear translocation of stat3, a newly identified member of the signal transducers and activators of transcription (STAT) family of proteins. In contrast, stat1 proteins were not tyrosine phosphorylated after IL-2 ligation, whereas...... an apparent molecular mass of 84 kDa and was not recognized by stat3 or stat1 mAb or antisera. Since IL-2 induced nuclear translocation of the 84 kDa protein and stat3 followed identical kinetics, p84 is a candidate for a new, yet undefined, member of the STAT family. Taken together, we report that...... IL-2 induces tyrosine phosphorylation and subsequent nuclear translocation of stat3 and an as yet undefined 84-kDa protein in antigen-specific human T cell lines....

  18. Preliminary mechanistic research on STAT3 and ErbB2 RNAi as targets for radiation sensitization in astrocytoma cell

    International Nuclear Information System (INIS)

    Constitutively activated STAT3 and ErbB2 are involved in pathogenesis of many tumors including astrocytoma. The effects of plasmid vector mediated STAT3 and ErbB2 RNAi on growth of U251 astrocytoma cell line were examined. Increased apoptosis and decreased proliferation were induced by STAT3 and ErbB2 RNAi in U251 cell. STAT3 and ErbB2 RNAi showed synergetic effect. Combination of RNAi and irradiation showed synergetic effect. However, STAT3 and ErbB2 RNAi showed no obvious effects on NA cell. At the same time, an U251 xenograft model was used to determine the in vivo effect of combined therapy of RNAi and irradiation. The result suggested that both STAT3 RNAi and ErbB2 RNAi could inhibit the tumor growth. The effect was more pronounced when the two genes were both down regulated. Comparing STAT3 RNAi or ErbB2 RNAi alone respectively, STAT3 RNAi plus 2 Gy radiotherapy or ErbB2 RNAi plus 2 Gy radiotherapy further inhibited the tumor growth. Among the different treatment, combining STAT3 and ErbB2 RNAi with 2 Gy radiotherapy lead to the most significant inhibition of tumor growth. (author)

  19. Stat3 Expression and Its Correlation with Proliferation and Apoptosis/Autophagy in Gliomas

    Directory of Open Access Journals (Sweden)

    Valentina Caldera

    2008-01-01

    Full Text Available Signal transducer and activator of transcription-3 (Stat3 was studied along with several steps of the PI3/Akt pathway in a series of 64 gliomas that included both malignant and low-grade tumors, using quantitative immunohistochemistry, Western blotting, and molecular biology techniques. The goal of the study was to investigate whether activated Stat3 (phospho-Stat3 levels correlated with cell proliferation, apoptosis, and autophagy. Stat3 and activated Akt (phospho-Akt expression increased with malignancy grade, but did not correlate with proliferation and survival within the category of glioblastomas. A correlation of Stat3 with Akt was found, indicating a regulation of the former by the PI3/Akt pathway, which, in turn, was in relation with EGFR amplification. Stat3 and Akt did not show any correlation with apoptosis, whereas they showed an inverse correlation with Beclin 1, a stimulator of autophagy, which was rarely positive in glioblastomas. Autophagy seems then to be inactivated in malignant gliomas.

  20. Analysis list: Stat3 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Stat3 Blood,Digestive tract,Neural + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u.../mm9/target/Stat3.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Stat3.5.tsv http://dbarchive.b...iosciencedbc.jp/kyushu-u/mm9/target/Stat3.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Stat3.Blood.tsv,http://dba...rchive.biosciencedbc.jp/kyushu-u/mm9/colo/Stat3.Digestive_tract.tsv,http://dba...rchive.biosciencedbc.jp/kyushu-u/mm9/colo/Stat3.Neural.tsv http://dbarchive.biosciencedbc.jp

  1. Sip-jeon-dea-bo-tang, a traditional herbal medicine, ameliorates cisplatin-induced anorexia via the activation of JAK1/STAT3-mediated leptin and IL-6 production in the fat tissue of mice.

    Science.gov (United States)

    Woo, Sang-Mi; Choi, Youn Kyung; Kim, Ah-Jeong; Yun, Yee Jin; Shin, Yong Cheol; Cho, Sung-Gook; Ko, Seong Gyu

    2016-04-01

    Despite its therapeutic advantages, chemotherapy can also cause adverse effects, including anorexia and loss of appetite. Although numerous patients with cancer have been reported to suffer from anorexia during or following chemotherapy, treatment options for anorexia remain to be determined. In Asian countries, traditional medicines are widely used to treat problems with appetite; sip-jeon-dea-bo-tang (SJDBT) is one of those medicines used for the treatment of anorexia. The present study demonstrated that SJDBT ameliorated cisplatin-induced anorexia. In a mouse model of chemotherapy-induced anorexia, oral administration of SJDBT prevented the cisplatin-induced reduction of food intake, inhibiting weight loss. The results of multiplex assays showed that SJDBT only altered the levels of interleukin (IL)-6 and leptin in the serum and fat tissue. In addition, SJDBT maintained the serum leptin level and increased the serum IL-6 level, whereas cisplatin reduced the levels of both serum leptin and IL‑6. Furthermore, SJDBT was revealed to increase the levels of leptin and IL-6 in the fat tissue by activating the JAK1/STAT3 signaling pathway. In conclusion, the present results revealed that SJDBT ameliorated cisplatin-induced anorexia, suggesting its usefulness in the prevention of anorexia during chemotherapy. PMID:26936678

  2. (-)-Epigallocatechin-3-gallate inhibits VEGF expression induced by IL-6 via Stat3 in gastric cancer

    Institute of Scientific and Technical Information of China (English)

    Bao-He Zhu; Hua-Yun Chen; Wen-Hua Zhan; Cheng-You Wang; Shi-Rong Cai; Zhao Wang; Chang-Hua Zhang; Yu-Long He

    2011-01-01

    AIM: To demonstrate that (-)-Epigallocatechin-3-gallate (EGCG) inhibits vascular endothelial growth factor (VEGF) expression and angiogenesis induced by interleukin-6 (IL-6) via suppressing signal transducer and activator of transcription 3 (Stat3) activity in gastric cancer.METHODS: Human gastric cancer (AGS) cells were treated with IL-6 (50 ng/mL) and EGCG at different concentrations. VEGF, total Stat3 and activated Stat3 protein levels in the cell lyses were examined by Western blotting, VEGF protein level in the conditioned medium was measured by enzyme-linked immunosorbent assay, and the level of VEGF mRNA was evaluated by reverse transcription polymerase chain reaction (RTPCR).Stat3 nuclear translocation was determined by Western blotting with nuclear extract, and Stat3-DNA binding activity was examined with Chromatin immunoprecipitation (ChIP) assay. IL-6 induced endothelial cell proliferation was measured with 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazoliumbromide assay, in vitro angiogenesis was determined with endothelial cell tube formation assay in Matrigel, and IL-6-induced angiogenesis in vitro was measured with Matrigel plug assay.RESULTS: There was a basal expression and secretion of VEGF in AGS cells. After stimulation with IL-6, VEGF expression was apparently up-regulated and a 2.4-fold increase was observed. VEGF secretion in the conditioned medium was also increased by 2.8 folds. When treated with EGCG, VEGF expression and secretion were dose-dependently decreased. IL-6 also increased VEGF mRNA expression by 3.1 folds. EGCG treatment suppressed VEGF mRNA expression in a dose-dependent manner. EGCG dose-dependently inhibited Stat3 activation induced by IL-6, but did not change the total Stat3 expression. When treated with EGCG or AG490,VEGF expressions were reduced to the level or an even lower level in the tumor cells not stimulated with IL-6. However, PD98059 and LY294002 did not change VEGF expression induced by IL-6. EGCG inhibited

  3. STAT-3 contributes to pulmonary fibrosis through epithelial injury and fibroblast-myofibroblast differentiation.

    Science.gov (United States)

    Pedroza, Mesias; Le, Thuy T; Lewis, Katherine; Karmouty-Quintana, Harry; To, Sarah; George, Anuh T; Blackburn, Michael R; Tweardy, David J; Agarwal, Sandeep K

    2016-01-01

    Lung fibrosis is the hallmark of the interstitial lung diseases. Alveolar epithelial cell (AEC) injury is a key step that contributes to a profibrotic microenvironment. Fibroblasts and myofibroblasts subsequently accumulate and deposit excessive extracellular matrix. In addition to TGF-β, the IL-6 family of cytokines, which signal through STAT-3, may also contribute to lung fibrosis. In the current manuscript, the extent to which STAT-3 inhibition decreases lung fibrosis is investigated. Phosphorylated STAT-3 was elevated in lung biopsies from patients with idiopathic pulmonary fibrosis and bleomycin (BLM)-induced fibrotic murine lungs. C-188-9, a small molecule STAT-3 inhibitor, decreased pulmonary fibrosis in the intraperitoneal BLM model as assessed by arterial oxygen saturation (control, 84.4 ± 1.3%; C-188-9, 94.4 ± 0.8%), histology (Ashcroft score: untreated, 5.4 ± 0.25; C-188-9, 3.3 ± 0.14), and attenuated fibrotic markers such as diminished α-smooth muscle actin, reduced collagen deposition. In addition, C-188-9 decreased the expression of epithelial injury markers, including hypoxia-inducible factor-1α (HIF-1α) and plasminogen activator inhibitor-1 (PAI-1). In vitro studies show that inhibition of STAT-3 decreased IL-6- and TGF-β-induced expression of multiple genes, including HIF-1α and PAI-1, in AECs. Furthermore, C-188-9 decreased fibroblast-to-myofibroblast differentiation. Finally, TGF-β stimulation of lung fibroblasts resulted in SMAD2/SMAD3-dependent phosphorylation of STAT-3. These findings demonstrate that STAT-3 contributes to the development of lung fibrosis and suggest that STAT-3 may be a therapeutic target in pulmonary fibrosis.

  4. STAT3RNA干扰对脑胶质瘤U251细胞活性氧含量及DNA损伤的影响%Effects of signal transducer and activator of transcription 3 RNAi on content of reactive oxygen species and DNA damage in glioma cell

    Institute of Scientific and Technical Information of China (English)

    高玲; 李峰生; 董波; 刘丽卉; 刘青杰; 陈肖华; 毛秉智

    2011-01-01

    Objective To investigate the effects of signal transducer and activator of transcription 3 (STAT3) RNAi on the content of reactive oxygen species (ROS) and the DNA damage in glioma cells.Methods Glioma cells of the line U251 cells were cultured and transfected with STAT3 RNAi plasmid (pSilencer2.1-STAT3,STAT3 group) and pSilencer2.1-GFP (GFP control group) respectively.Part of the U251 cells were irradiated with γ-rays of 60Co as positive control group of smear phenomenon.The levels of ROS and malondialdehyde (MDA) in the cells were detected 24,48,and 72 h later by flow cytometry and fluorescence chamoluminescence analyzer,respectively.The DNA damage in the transfected U251 cells was examined by using single cell gel electrophoresis assay,and the cell cycle distribution was examined using FACS PI staining 12,24,and 36 h later.Results At 24 h after the transfection,the ROS level of the siSTAT3-transfected ceils was 8.91 times that of the control group (F = 89.296,P < 0.05),and returned to the normal level 48 h later.There were not significant differences in the MDA level of the cells 24,48,and 72 h later between the siSTAT3 group and siGFP group.Compared with the 8 Gy irradiation positive group with obvious smear phenomenon,smear phenomenon was shown in part of the ceils in the siSTAT3 group 6 h later,became less 12 h later,and disappeared completely 24 h later.Compared with the control group,lag of S stage rate was 17.22% and the lag of G2/M stage rate was 6.4% 12 h later in the siSTAT-transfected group,and the G0/G1 stage lag rate was 18.44% 24 h later,and the lag of S stage rate was 17.99% 36 h later.Conclusions Inhibition of STAT3 results in the change of oxidoreduction status in glioma cells,as well as damage and reparation of DNA.%目的 探讨STAT3 RNA干扰(RNAi)对脑胶质瘤U251细胞活性氧含量及DNA损伤的影响.方法 利用构建好的STAT3 RNAi载体(pSilencer2.1-STAT3,STAT3组)和pSileneer2.1-GFP(RNAi对照组)分别转染U251

  5. Macrophages promote benzopyrene-induced tumor transformation of human bronchial epithelial cells by activation of NF-κB and STAT3 signaling in a bionic airway chip culture and in animal models.

    Science.gov (United States)

    Li, Encheng; Xu, Zhiyun; Zhao, Hui; Sun, Zhao; Wang, Lei; Guo, Zhe; Zhao, Yang; Gao, Zhancheng; Wang, Qi

    2015-04-20

    We investigated the role of macrophages in promoting benzopyrene (BaP)-induced malignant transformation of human bronchial epithelial cells using a BaP-induced tumor transformation model with a bionic airway chip in vitro and in animal models. The bionic airway chip culture data showed that macrophages promoted BaP-induced malignant transformation of human bronchial epithelial cells, which was mediated by nuclear factor (NF)-κB and STAT3 pathways to induce cell proliferation, colony formation in chip culture, and tumorigenicity in nude mice. Blockage of interleukin (IL)-6 or tumor necrosis factor (TNF)-α signaling or inhibition of NF-κB, STAT3, or cyclinD1 expression abrogated the effect of macrophages on malignant transformation in the bionic airway chip culture. In vivo, macrophages promoted lung tumorigenesis in a carcinogen-induced animal model. Similarly, blockage of NF-κB, STAT3, or cyclinD1 using siRNA transfection decreased the carcinogen-induced tumorigenesis in rats. We demonstrated that macrophages are critical in promoting lung tumorigenesis and that the macrophage-initiated TNF-α/NF-κB/cyclinD1 and IL-6/STAT3/cyclinD1 pathways are primarily responsible for promoting lung tumorigenesis.

  6. IL-6/STAT3/TFF3 signaling regulates human biliary epithelial cell migration and wound healing in vitro.

    Science.gov (United States)

    Jiang, Gui-xing; Zhong, Xiang-yu; Cui, Yun-fu; Liu, Wei; Tai, Sheng; Wang, Zhi-dong; Shi, Yu-guang; Zhao, Shi-yong; Li, Chun-long

    2010-12-01

    Interleukin-6 (IL-6), through activation of the signal transducer and activator of transcription 3 (STAT3) and trefoil factor family 3 (TFF3), has been implicated in the promotion of mouse biliary epithelial cell (BEC) proliferation and migration. However, it is still unclear whether the IL-6/STAT3/TFF3 signaling had similar effects on human BECs. Here, we showed that exposure of human BECs to recombinant IL-6 resulted in STAT3 phosphorylation and increased the expression of TFF3 at both mRNA and protein levels. Moreover, inhibition of STAT3 using RNA interference significantly abrogated IL-6-induced TFF3 expression. In an in-vitro wound healing model, IL-6 facilitated human BEC migration. This promotion of cell migration by IL-6 was blocked when STAT3 was knocked down. Interestingly, the addition of exogenous TFF3 could rescue the cell migration defects caused by STAT3 silencing. In conclusion, our data indicate that STAT3 plays a critical role in IL-6-induced TFF3 expression in human BECs and the IL-6/STAT3/TFF3 signaling is involved in human BEC migration and wound healing.

  7. STAT3 Signaling in B Cells Is Critical for Germinal Center Maintenance and Contributes to the Pathogenesis of Murine Models of Lupus.

    Science.gov (United States)

    Ding, Chuanlin; Chen, Xingguo; Dascani, Paul; Hu, Xiaoling; Bolli, Roberto; Zhang, Huang-Ge; Mcleish, Kenneth R; Yan, Jun

    2016-06-01

    Ab maturation as well as memory B and plasma cell differentiation occur primarily in the germinal centers (GCs). Systemic lupus erythematosus (SLE) may develop as a result of enhanced GC activity. Previous studies have shown that the dysregulated STAT3 pathway is linked to lupus pathogenesis. However, the exact role of STAT3 in regulating SLE disease progression has not been fully understood. In this study, we demonstrated that STAT3 signaling in B cells is essential for GC formation and maintenance as well as Ab response. Increased cell apoptosis and downregulated Bcl-xL and Mcl-1 antiapoptotic gene expression were found in STAT3-deficient GC B cells. The follicular helper T cell response positively correlated with GC B cells and was significantly decreased in immunized B cell STAT3-deficient mice. STAT3 deficiency also led to the defect of plasma cell differentiation. Furthermore, STAT3 deficiency in autoreactive B cells resulted in decreased autoantibody production. Results obtained from B cell STAT3-deficient B6.MRL/lpr mice suggest that STAT3 signaling significantly contributes to SLE pathogenesis by regulation of GC reactivity, autoantibody production, and kidney pathology. Our findings provide new insights into the role of STAT3 signaling in the maintenance of GC formation and GC B cell differentiation and identify STAT3 as a novel target for treatment of SLE. PMID:27183592

  8. BIS-mediated STAT3 stabilization regulates glioblastoma stem cell-like phenotypes

    Science.gov (United States)

    Im, Chang-Nim; Yun, Hye Hyeon; Song, Byunghoo; Youn, Dong-Ye; Cui, Mei Nu; Kim, Hong Sug; Park, Gyeong Sin; Lee, Jeong-Hwa

    2016-01-01

    Glioblastoma stem cells (GSCs) are a subpopulation of highly tumorigenic and stem-like cells that are responsible for resistance to conventional therapy. Bcl-2-intreacting cell death suppressor (BIS; also known as BAG3) is an anti-apoptotic protein that is highly expressed in human cancers with various origins, including glioblastoma. In the present study, to investigate the role of BIS in GSC subpopulation, we examined the expression profile of BIS in A172 and U87-MG glioblastoma cell lines under specific in vitro culture conditions that enrich GSC-like cells in spheres. Both BIS mRNA and protein levels significantly increased under the sphere-forming condition as compared with standard culture conditions. BIS depletion resulted in notable decreases in sphere-forming activity and was accompanied with decreases in SOX-2 expression. The expression of STAT3, a master regulator of stemness, also decreased following BIS depletion concomitant with decreases in the nuclear levels of active phosphorylated STAT3, while ectopic STAT3 overexpression resulted in recovery of sphere-forming activity in BIS-knockdown glioblastoma cells. Additionally, immunoprecipitation and confocal microscopy revealed that BIS physically interacts with STAT3. Furthermore, BIS depletion increased STAT3 ubiquitination, suggesting that BIS is necessary for STAT3 stabilization in GSC-like cells. BIS depletion also affected epithelial-to-mesenchymal transition-related genes as evidenced by decrease in SNAIL and MMP-2 expression and increase in E-cadherin expression in GSC-like cells. Our findings suggest that high levels of BIS expression might confer stem-cell-like properties on cancer cells through STAT3 stabilization, indicating that BIS is a potential target in cancer therapy. PMID:27145367

  9. Cardamonin induces apoptosis by suppressing STAT3 signaling pathway in glioblastoma stem cells.

    Science.gov (United States)

    Wu, Ning; Liu, Jia; Zhao, Xiangzhong; Yan, Zhiyong; Jiang, Bo; Wang, Lijun; Cao, Shousong; Shi, Dayong; Lin, Xiukun

    2015-12-01

    Glioblastoma stem cells (GSCs) are the initiating cells in glioblastoma multiforme (GBM) and contribute to the resistance of GBM to chemotherapy and radiation. In the present study, we investigated the effects of cardamonin (3,4,2,4-tetrahydroxychalcone) on the self-renewal and apoptosis of GSCs, and if its action is associated with signal transducer and activator of transcription 3 (STAT3) pathway. CD133(+) GSCs, a kind of GSCs line, was established from human glioblastoma tissues. Cardamonin inhibited the proliferation and induced apoptosis in CD133+ GSCs. The proapoptotic effects of temozolomide (TMZ) were further enhanced by cardamonin in CD133+ GSCs and U87 cells in vitro. For in vivo study, injection of 5 × 10(5) cells of CD133+ GSCs subcutaneously (s.c.) into nude mice, 100 % of large tumors were developed within 8 weeks in all mice; in contrast, only one out of five mice developed a small tumor when 5 × 10(5) cells of CD133(-) GMBs cells were injected. Cardamonin also inhibited STAT3 activation by luciferase assay and suppressed the expression of the downstream genes of STAT3, such as Bcl-XL, Bcl-2, Mcl-1, survivin, and VEGF. Furthermore, cardamonin locked nuclear translocation and dimerization of STAT3 in CD133(+) GSCs. Docking analysis confirmed that cardamonin molecule was successfully docked into the active sites of STAT3 with a highly favorable binding energy of -10.78 kcal/mol. The study provides evidence that cardamonin is a novel inhibitor of STAT3 and has the potential to be developed as a new anticancer agent targeting GSCs. This study also reveals that targeting STAT3 signal pathway is an important strategy for the treatment of human GBM. PMID:26150336

  10. STAT3 blockade enhances the efficacy of conventional chemotherapeutic agents by eradicating head neck stemloid cancer cell.

    Science.gov (United States)

    Bu, Lin-Lin; Zhao, Zhi-Li; Liu, Jian-Feng; Ma, Si-Rui; Huang, Cong-Fa; Liu, Bing; Zhang, Wen-Feng; Sun, Zhi-Jun

    2015-12-01

    Signaling transducer and activator 3 (STAT3) and cancer stem cells (CSCs) have garnered huge attention as a therapeutic focus, based on evidence that they may represent an etiologic root of tumor initiation and radio-chemoresistance. Here, we investigated the high phosphorylation status of STAT3 (p-STAT3) and its correlation with self-renewal markers in head neck squamous cell carcinoma (HNSCC). Over-expression of p-STAT3 was found to have increased in post chemotherapy HNSCC tissue. We showed that blockade of p-STAT3 eliminated both bulk tumor and side population (SP) cells with characteristics of CSCs in vitro. Inhibition of p-STAT3 using small molecule S3I-201 significantly delayed tumorigenesis of spontaneous HNSCC in mice. Combining blockade of p-STAT3 with cytotoxic drugs cisplatin, docetaxel, 5-fluorouracil (TPF) enhanced the antitumor effect in vitro and in vivo with decreased tumor sphere formation and SP cells. Taken together, our results advocate blockade of p-STAT3 in combination with conventional chemotherapeutic drugs enhance efficacy by improving CSCs eradication in HNSCC. PMID:26556875

  11. Knockdown of STAT3 by iRNA Inhibiting Migration and Invasion of Epithelial Ovarian Cancer Cells

    Institute of Scientific and Technical Information of China (English)

    LI Qin-hua; ZHU Ji-hong; LIU Lei; YUE Ying

    2012-01-01

    Signal transducer and activator of transcription 3(STAT3) is a dual functional transcription factor with the functions of signal transduction and transcription regulation.It is reported that the expression of STAT3 in ovarian cancer is significantly higher and STAT3 can facilitate ovarian cancer growth and metastasis.To clarify the definite effect and molecular mechanism of STAT3 involved in ovarian cancer growth and metastasis,STAT3 expression was significantly downregulated by transfeeting ovarian cancer model SK-OV-3 cells with the plasmid vector which express specific RNAi that targets human STAT3.The downregulated STAT3 not only decreased the invasion and migration but also inhibited the proliferation of SK-OV-3 cells.Western blot assay shows that the expression of vascular endothelial growth factor(VEGF) and that of Survivin were reduced in the cells with the plasma vector expressing specific RNAi that targets human STATY These results demonstrate that STAT3 involved in the invasion and migration of SK-OV-3 regulates the expression of VEGF and Survivin.In addition,VEGF and Survivin could play an important role in ovarian cancer growth and metastasis.

  12. IL10-driven STAT3 signalling in senescent macrophages promotes pathological eye angiogenesis.

    Science.gov (United States)

    Nakamura, Rei; Sene, Abdoulaye; Santeford, Andrea; Gdoura, Abdelaziz; Kubota, Shunsuke; Zapata, Nicole; Apte, Rajendra S

    2015-01-01

    Macrophage dysfunction plays a pivotal role during neovascular proliferation in diseases of ageing including cancers, atherosclerosis and blinding eye disease. In the eye, choroidal neovascularization (CNV) causes blindness in patients with age-related macular degeneration (AMD). Here we report that increased IL10, not IL4 or IL13, in senescent eyes activates STAT3 signalling that induces the alternative activation of macrophages and vascular proliferation. Targeted inhibition of both IL10 receptor-mediated signalling and STAT3 activation in macrophages reverses the ageing phenotype. In addition, adoptive transfer of STAT3-deficient macrophages into eyes of old mice significantly reduces the amount of CNV. Systemic and CD163(+) eye macrophages obtained from AMD patients also demonstrate STAT3 activation. Our studies demonstrate that impaired SOCS3 feedback leads to permissive IL10/STAT3 signalling that promotes alternative macrophage activation and pathological neovascularization. These findings have significant implications for our understanding of the pathobiology of age-associated diseases and may guide targeted immunotherapy. PMID:26260587

  13. STAT3 mutations correlated with hyper-IgE syndrome lead to blockage of IL-6/STAT3 signalling pathway

    Indian Academy of Sciences (India)

    Jianxin He; Jie Shi; Ximing Xu; Wenhua Zhang; Yuxin Wang; Xing Chen; Yuping Du; Ning Zhu; Jing Zhang; Qin Wang; Jinbo Yang

    2012-06-01

    Of all the causes identified for the disease hyper-immunoglobulinemia E syndrome (HIES), a homozygous mutation in tyrosine kinase2 (TYK2) and heterozygous mutations in STAT3 are implicated the defects in Jak/STAT signalling pathway in the pathogenesis of HIES. Mutations of STAT3 have been frequently clinically identified in autosomal-dominant (AD) HIES patients’ cells, and therefore, the genotype of STAT3 has been associated with the phenotype of HIES. Here, we conducted studies on the functional loss of the seven specific STAT3 mutations correlated with ADHIES. Using STAT3-null human colon carcinoma cell line A4 cells, we generated seven mutants of STAT3 bearing single mutations clinically identified in AD-HIES patients’ cells and studied the functional loss of these mutants in IL-6-Jak/STAT3 signalling pathway. Our results show that five STAT3 mutants bearing mutations in the DNA-binding domain maintain the phosphorylation of Tyr705 and the ability of dimerization while the other two with mutations in SH2 domain are devoid of the phosphorylation of Try705 and abrogate the dimerization in response to IL-6. The phosphorylation of Ser727 in these mutants shows diversity in response to IL-6. These mutations eventually converge on the abnormalities of the IL-6/Gp130/Jak2-mediated STAT3 transactivation on target genes, indicative of the dysregulation of JAK/STAT signalling present in HIES.

  14. Inhibition of mammalian target of rapamycin protects against reperfusion injury in diabetic heart through STAT3 signaling.

    Science.gov (United States)

    Das, Anindita; Salloum, Fadi N; Filippone, Scott M; Durrant, David E; Rokosh, Gregg; Bolli, Roberto; Kukreja, Rakesh C

    2015-05-01

    Diabetic patients suffer augmented severity of myocardial infarction. Excessive activation of the mammalian target of rapamycin (mTOR) and decreased activation of STAT3 are implicated in diabetic complications. Considering the potent cardioprotective effect of mTOR inhibitor, rapamycin, we hypothesized that reperfusion therapy with rapamycin would reduce infarct size in the diabetic hearts through STAT3 signaling. Hearts from adult male db/db or wild type (WT) C57 mice were isolated and subjected to 30 min of normothermic global ischemia and 60 min of reperfusion in Langendorff mode. Rapamycin (100 nM) was infused at the onset of reperfusion. Myocardial infarct size (IS) was significantly reduced in rapamycin-treated mice (13.3 ± 2.4 %) compared to DMSO vehicle control (35.9 ± 0.9 %) or WT mice (27.7 ± 1.1 %). Rapamycin treatment restored phosphorylation of STAT3 and enhanced AKT phosphorylation (target of mTORC2), but significantly reduced ribosomal protein S6 phosphorylation (target of mTORC1) in the diabetic heart. To determine the cause and effect relationship of STAT3 in cardioprotection, inducible cardiac-specific STAT3-deficient (MCM TG:STAT3(flox/flox)) and WT mice (MCM TG:STAT3(flox/flox)) were made diabetic by feeding high fat diet (HFD). Rapamycin given at reperfusion reduced IS in WT mice but not in STAT3-deficient mice following I/R. Moreover, cardiomyocytes isolated from HFD-fed WT mice showed resistance against necrosis (trypan blue staining) and apoptosis (TUNEL assay) when treated with rapamycin during reoxygenation following simulated ischemia. Such protection was absent in cardiomyocytes from HFD-fed STAT3-deficient mice. STAT3 signaling plays critical role in reducing IS and attenuates cardiomyocyte death following reperfusion therapy with rapamycin in diabetic heart.

  15. Vaccinia virus induces rapid necrosis in keratinocytes by a STAT3-dependent mechanism.

    Directory of Open Access Journals (Sweden)

    Yong He

    Full Text Available Humans with a dominant negative mutation in STAT3 are susceptible to severe skin infections, suggesting an essential role for STAT3 signaling in defense against cutaneous pathogens.To focus on innate antiviral defenses in keratinocytes, we used a standard model of cutaneous infection of severe combined immunodeficient mice with the current smallpox vaccine, ACAM-2000. In parallel, early events post-infection with the smallpox vaccine ACAM-2000 were investigated in cultured keratinocytes of human and mouse origin.Mice treated topically with a STAT3 inhibitor (Stattic developed larger vaccinia lesions with higher virus titers and died more rapidly than untreated controls. Cultured human and murine keratinocytes infected with ACAM-2000 underwent rapid necrosis, but when treated with Stattic or with inhibitors of RIP1 kinase or caspase-1, they survived longer, produced higher titers of virus, and showed reduced activation of type I interferon responses and inflammatory cytokines release. Treatment with inhibitors of RIP1 kinase and STAT3, but not caspase-1, also reduced the inflammatory response of keratinocytes to TLR ligands. Vaccinia growth properties in Vero cells, which are known to be defective in some antiviral responses, were unaffected by inhibition of RIP1K, caspase-1, or STAT3.Our findings indicate that keratinocytes suppress the replication and spread of vaccinia virus by undergoing rapid programmed cell death, in a process requiring STAT3. These data offer a new framework for understanding susceptibility to skin infection in patients with STAT3 mutations. Interventions which promote prompt necroptosis/pyroptosis of infected keratinocytes may reduce risks associated with vaccination with live vaccinia virus.

  16. Silencing of the transcription factor STAT3 sensitizes lung cancer cells to DNA damaging drugs, but not to TNFα- and NK cytotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Kulesza, Dorota W. [Laboratory of Transcription Regulation, Department of Cell Biology, The Nencki Institute of Experimental Biology, Warsaw (Poland); Postgraduate School of Molecular Medicine, Warsaw Medical University, Warsaw (Poland); Carré, Thibault; Chouaib, Salem [Unité INSERM U753, Institut de Cancérologie Gustave Roussy, Villejuif Cedex (France); Kaminska, Bozena, E-mail: bozenakk@nencki.gov.pl [Laboratory of Transcription Regulation, Department of Cell Biology, The Nencki Institute of Experimental Biology, Warsaw (Poland)

    2013-02-15

    Transcription factor STAT3 (Signal Transducers and Activators of Transcription 3) is persistently active in human tumors and may contribute to tumor progression. Inhibition of STAT3 expression/activity could be a good strategy to modulate tumor cell survival and responses to cancer chemotherapeutics or immune cytotoxicity. We silenced STAT3 expression in human A549 lung cancer cells to elucidate its role in cell survival and resistance to chemotherapeutics, TNFα and natural killer (NK)-mediated cytotoxicity. We demonstrate that STAT3 is not essential for basal survival and proliferation of A549 cancer cells. Stable silencing of STAT3 expression sensitized A549 cells to DNA damaging chemotherapeutics doxorubicin and cisplatin in a p53-independent manner. Sensitization to DNA damage-inducing chemotherapeutics could be due to down-regulation of the Bcl-xL expression in STAT3 depleted cells. In contrast, knockdown of STAT3 in cancer cells did not modulate responses to TNFα and NK-mediated cytotoxicity. We found that STAT3 depletion increased the NFκB activity likely providing the compensatory, pro-survival signal. The treatment with TNFα, but not doxorubicin, enhanced this effect. We conclude that STAT3 is not crucial for the control of basal cell proliferation and survival of lung carcinoma cells but modulates susceptibility to DNA damaging chemotherapeutics by regulation of intrinsic pro-survival pathways. - Highlights: ► STAT3 silencing is negligent for basal lung cancer cell viability and proliferation. ► STAT3 depletion sensitizes lung cancer cells to DNA damaging chemotherapeutics. ► STAT3 depletion has no effect on susceptibility to extrinsic apoptosis inducers. ► Increased pro-survival NFκB activity may compensate for STAT3 depletion.

  17. Macrophages promote benzopyrene-induced tumor transformation of human bronchial epithelial cells by activation of NF-κB and STAT3 signaling in a bionic airway chip culture and in animal models

    OpenAIRE

    Li, Encheng; Xu, Zhiyun; Zhao, Hui; Sun, Zhao; Wang, Lei; Guo, Zhe; Zhao, Yang; GAO, ZHANCHENG; Wang, Qi

    2015-01-01

    We investigated the role of macrophages in promoting benzopyrene (BaP)-induced malignant transformation of human bronchial epithelial cells using a BaP-induced tumor transformation model with a bionic airway chip in vitro and in animal models. The bionic airway chip culture data showed that macrophages promoted BaP-induced malignant transformation of human bronchial epithelial cells, which was mediated by nuclear factor (NF)-κB and STAT3 pathways to induce cell proliferation, colony formation...

  18. Implication of STAT3 signaling in human colonic cancer cells during intestinal trefoil factor 3 (TFF3) -- and vascular endothelial growth factor-mediated cellular invasion and tumor growth.

    Science.gov (United States)

    Rivat, Christine; Christine, Rivat; Rodrigues, Sylvie; Sylvie, Rodrigues; Bruyneel, Erik; Erik, Bruyneel; Piétu, Geneviève; Geneviève, Piétu; Robert, Amélie; Amélie, Robert; Redeuilh, Gérard; Gérard, Redeuilh; Bracke, Marc; Marc, Bracke; Gespach, Christian; Christian, Gespach; Attoub, Samir; Samir, Attoub

    2005-01-01

    Signal transducer and activator of transcription (STAT) 3 is overexpressed or activated in most types of human tumors and has been classified as an oncogene. In the present study, we investigated the contribution of the STAT3s to the proinvasive activity of trefoil factors (TFF) and vascular endothelial growth factor (VEGF) in human colorectal cancer cells HCT8/S11 expressing VEGF receptors. Both intestinal trefoil peptide (TFF3) and VEGF, but not pS2 (TFF1), activate STAT3 signaling through Tyr(705) phosphorylation of both STAT3alpha and STAT3beta isoforms. Blockade of STAT3 signaling by STAT3beta, depletion of the STAT3alpha/beta isoforms by RNA interference, and pharmacologic inhibition of STAT3alpha/beta phosphorylation by cucurbitacin or STAT3 inhibitory peptide abrogates TFF- and VEGF-induced cellular invasion and reduces the growth of HCT8/S11 tumor xenografts in athymic mice. Differential gene expression analysis using DNA microarrays revealed that overexpression of STAT3beta down-regulates the VEGF receptors Flt-1, neuropilins 1 and 2, and the inhibitor of DNA binding/differentiation (Id-2) gene product involved in the neoplastic transformation. Taken together, our data suggest that TFF3 and the essential tumor angiogenesis regulator VEGF(165) exert potent proinvasive activity through STAT3 signaling in human colorectal cancer cells. We also validate new therapeutic strategies targeting STAT3 signaling by pharmacologic inhibitors and RNA interference for the treatment of colorectal cancer patients.

  19. Expression analysis of Stat3 in human lung carcinoma

    Institute of Scientific and Technical Information of China (English)

    WANG Hong; HAN Yi-ping

    2002-01-01

    Objective: To analyze the relationship of Stat3 expression with clinical stages, tissue types, p53and proliferation cell nuclear antigen (PCNA) in human lung carcinoma, and to evaluate the role of Stat3 in the pathogenesis of lung carcinoma. Methods: Immunohistochemical method were used to detected Stat3,p53 and PCNA in different tissues of patients (n= 42) with lung carcinoma who accepted neither radiotherapy nor chemotherapy. Results: The positive rate of Stat3 was 81.0% in lung carcinoma and its expression level was related to the tissue type but not to T, N or the clinical stage. The expression level of Stat3 in non-small cell lung carcinoma (NSCLC) was higher than that in small cell lung carcinoma (SCLC). A positive correlation of the expression of Stat3 with that of p53 and PCNA was identified. Conclusion: The expression level of Stat3 is abnormal in lung carcinoma. Stat3 may be involved in the regulation of p53 gene in lung carcinoma cell, it may accelerate the proliferation of lung carcinoma cells and play an important role in the pathogenesis of lung carcinoma.

  20. Saw Palmetto Extract Inhibits Metastasis and Antiangiogenesis through STAT3 Signal Pathway in Glioma Cell

    Directory of Open Access Journals (Sweden)

    Hong Ding

    2015-01-01

    Full Text Available Signal transducer and activator of transcription factor 3 (STAT3 plays an important role in the proliferation and angiogenesis in human glioma. Previous research indicated that saw palmetto extract markedly inhibited the proliferation of human glioma cells through STAT3 signal pathway. But its effect on tumor metastasis and antiangiogenesis is not clear. This study is to further clear the impact of saw palmetto extract on glioma cell metastasis, antiangiogenesis, and its mechanism. TUNEL assay indicated that the apoptotic cells in the saw palmetto treated group are higher than that in the control group (p<0.05. The apoptosis related protein is detected and the results revealed that saw palmetto extract inhibits the proliferation of human glioma. Meanwhile pSTAT3 is lower in the experimental group and CD34 is also inhibited in the saw palmetto treated group. This means that saw palmetto extract could inhibit the angiogenesis in glioma. We found that saw palmetto extract was an important phytotherapeutic drug against the human glioma through STAT3 signal pathway. Saw palmetto extract may be useful as an adjunctive therapeutic agent for treatment of individuals with glioma and other types of cancer in which STAT3 signaling is activated.

  1. A novel small molecule STAT3 inhibitor, LY5, inhibits cell viability, colony formation, and migration of colon and liver cancer cells

    Science.gov (United States)

    Yu, Wenying; Jou, David; Wang, Yina; Ma, Haiyan; Xiao, Hui; Qin, Hua; Zhang, Cuntai; Lü, Jiagao; Li, Sheng; Li, Chenglong; Lin, Jiayuh; Lin, Li

    2016-01-01

    Signal Transducer and Activator of Transcription 3 (STAT3) is persistently activated in human liver and colon cancer cells and is required for cancer cell viability, survival and migration. Therefore, inhibition of STAT3 signaling may be a viable therapeutic approach for these two cancers. We recently designed a non-peptide small molecule STAT3 inhibitor, LY5, using in silico site-directed Fragment-based drug design (FBDD). The inhibitory effect on STAT3 phosphorylation, cell viability, migration and colony forming ability by LY5 were examined in human liver and colon cancer cells. We demonstrated that LY5 inhibited constitutive Interleukin-6 (IL-6)-induced STAT3 phosphorylation, STAT3 nuclear translocation, decreased STAT3 downstream targeted gene expression and induced apoptosis in liver and colon cancer cells. LY5 had little effect on STAT1 phosphorylation mediated by IFN-γ. Inhibition of persistent STAT3 phosphorylation by LY5 also inhibited colony formation, cell migration, and decreased the viability of liver cancer and colon cancer cells. Furthermore, LY5 inhibited STAT3 phosphorylation and suppressed colon tumor growth in a mouse model in vivo. Our results suggest that LY5 is a potent STAT3 inhibitor and may be a potential drug candidate for liver and colon cancer therapy. PMID:26883202

  2. RANKL downregulates cell surface CXCR6 expression through JAK2/STAT3 signaling pathway during osteoclastogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Li, Changhong; Zhao, Jinxia; Sun, Lin; Yao, Zhongqiang; Liu, Rui [Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing 100191 (China); Huang, Jiansheng [Department of Pediatrics, Washington University School of Medicine, St. Louis, MO (United States); Liu, Xiangyuan, E-mail: liu-xiangyuan@263.net [Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing 100191 (China)

    2012-12-14

    Highlights: Black-Right-Pointing-Pointer CXCR6 is down-regulated during RANKL-induced osteoclastogenesis in RAW264.7 cells. Black-Right-Pointing-Pointer CXCR6 reduction was nearly reversed by inhibition of JAK2/STAT3 signaling pathway. Black-Right-Pointing-Pointer CXCL16 alone does not positively regulate osteoclastogenesis. -- Abstract: The receptor activator of nuclear factor-{kappa}B ligand (RANKL), as a member of the tumor necrosis factor (TNF) family, plays an essential role in osteoclast differentiation and function. Chemokines and their receptors have recently been shown to play critical roles in osteoclastogenesis, however, whether CXCL16-CXCR6 plays role in RANKL-mediated osteoclastogenesis is unknown. In this study, we first reported that RANKL decreased CXCR6 in a dose-dependent manner, which may be through deactivation of Akt and STAT3 signaling induced by CXCL16. Interestingly, RANKL-mediated CXCR6 reduction may be associated to the activation of STAT3 by phosphorylation. When STAT3 activation was blocked by JAK2/STAT3 inhibitor AG490, RANKL failed to shut down CXCR6 expression during osteoclastogenesis. However, CXCL16 alone did not augment RANKL-mediated osteoclast differentiation and did not alter RANKL-receptor RANK mRNA expression. These results demonstrate that reduction of CXCL16-CXCR6 is critical in RANKL-mediated osteoclastogenesis, which is mainly through the activation of JAK2/STAT3 signaling. CXCL16-CXCR6 axis may become a novel target for the therapeutic intervention of bone resorbing diseases such as rheumatoid arthritis and osteoporosis.

  3. Ceramide Induces Human Hepcidin Gene Transcription through JAK/STAT3 Pathway.

    Directory of Open Access Journals (Sweden)

    Sizhao Lu

    Full Text Available Changes in lipid metabolism and iron content are observed in the livers of patients with fatty liver disease. The expression of hepcidin, an iron-regulatory and acute phase protein synthesized by the liver, is also modulated. The potential interaction of lipid and iron metabolism is largely unknown. We investigated the role of lipid intermediate, ceramide in the regulation of human hepcidin gene, HAMP. Human hepatoma HepG2 cells were treated with cell-permeable ceramide analogs. Ceramide induced significant up-regulation of HAMP mRNA expression in HepG2 cells. The effect of ceramide on HAMP expression was mediated through transcriptional mechanisms because it was completely blocked with actinomycin D treatment. Reporter assays also confirmed the activation of 0.6 kb HAMP promoter by ceramide. HepG2 cells treated with ceramide displayed increased phosphorylation of STAT3, JNK, and NF-κB proteins. However, ceramide induced the binding of STAT3, but not NF-κB or c-Jun, to HAMP promoter, as shown by the chromatin immunoprecipitation assays. The mutation of STAT3 response element within 0.6 kb HAMP promoter region significantly inhibited the stimulatory effect of ceramide on HAMP promoter activity. Similarly, the inhibition of STAT3 with a pan-JAK kinase inhibitor and STAT3 siRNA pool also diminished the induction of both HAMP promoter activity and mRNA expression by ceramide. In conclusion, we have shown a direct role for ceramide in the activation of hepatic HAMP transcription via STAT3. Our findings suggest a crosstalk between lipid and iron metabolism in the liver, which may contribute to the pathogenesis of obesity-related fatty liver disease.

  4. Ceramide Induces Human Hepcidin Gene Transcription through JAK/STAT3 Pathway.

    Science.gov (United States)

    Lu, Sizhao; Natarajan, Sathish Kumar; Mott, Justin L; Kharbanda, Kusum K; Harrison-Findik, Duygu Dee

    2016-01-01

    Changes in lipid metabolism and iron content are observed in the livers of patients with fatty liver disease. The expression of hepcidin, an iron-regulatory and acute phase protein synthesized by the liver, is also modulated. The potential interaction of lipid and iron metabolism is largely unknown. We investigated the role of lipid intermediate, ceramide in the regulation of human hepcidin gene, HAMP. Human hepatoma HepG2 cells were treated with cell-permeable ceramide analogs. Ceramide induced significant up-regulation of HAMP mRNA expression in HepG2 cells. The effect of ceramide on HAMP expression was mediated through transcriptional mechanisms because it was completely blocked with actinomycin D treatment. Reporter assays also confirmed the activation of 0.6 kb HAMP promoter by ceramide. HepG2 cells treated with ceramide displayed increased phosphorylation of STAT3, JNK, and NF-κB proteins. However, ceramide induced the binding of STAT3, but not NF-κB or c-Jun, to HAMP promoter, as shown by the chromatin immunoprecipitation assays. The mutation of STAT3 response element within 0.6 kb HAMP promoter region significantly inhibited the stimulatory effect of ceramide on HAMP promoter activity. Similarly, the inhibition of STAT3 with a pan-JAK kinase inhibitor and STAT3 siRNA pool also diminished the induction of both HAMP promoter activity and mRNA expression by ceramide. In conclusion, we have shown a direct role for ceramide in the activation of hepatic HAMP transcription via STAT3. Our findings suggest a crosstalk between lipid and iron metabolism in the liver, which may contribute to the pathogenesis of obesity-related fatty liver disease. PMID:26807955

  5. STAT3、CEA在人肺腺癌细胞A594中的相关性研究%Correlation of STAT3, CEA in lung adenocarcinoma cell A549

    Institute of Scientific and Technical Information of China (English)

    Debin Sun; Xiu Lan; Hongcheng Wang

    2012-01-01

    Objective: The purpose of this study was to analyze the relationship between signal transducer and activator of transcription 3 (STAT3) and carcinoembryonic antigen (CEA) in lung adenocarcinoma cell A549, and to explore the value of STAT3 on early diagnosis of lung adenocarcinoma. Methods: The expression of CEA, STAT3 mRNA and it's protein in human lung adenocarcinoma cell A549 and normal human lung cells MRC-5 were tested by immunohistochemistry staining (PV) and quantitative real time fluorescent PCR. The correlation between STAT3 and CEA in human lung adenocarcinoma cell A549 was analyzed. Results: The protein and mRNA levels of STAT3, CEA in lung adenocarcinoma cell A549 were apparently higher than those in normal human lung cells MRC-5. The levels of STAT3 mRNA and it's protein were positively correlated with CEA in lung adenocarcinoma cell A549. Conclusion: STAT3 have the same value in diagnosis of lung adenocarcinoma.

  6. STAT3 interrupts ATR-Chk1 signaling to allow oncovirus-mediated cell proliferation.

    Science.gov (United States)

    Koganti, Siva; Hui-Yuen, Joyce; McAllister, Shane; Gardner, Benjamin; Grasser, Friedrich; Palendira, Umaimainthan; Tangye, Stuart G; Freeman, Alexandra F; Bhaduri-McIntosh, Sumita

    2014-04-01

    DNA damage response (DDR) is a signaling network that senses DNA damage and activates response pathways to coordinate cell-cycle progression and DNA repair. Thus, DDR is critical for maintenance of genome stability, and presents a powerful defense against tumorigenesis. Therefore, to drive cell-proliferation and transformation, viral and cellular oncogenes need to circumvent DDR-induced cell-cycle checkpoints. Unlike in hereditary cancers, mechanisms that attenuate DDR and disrupt cell-cycle checkpoints in sporadic cancers are not well understood. Using Epstein-Barr virus (EBV) as a source of oncogenes, we have previously shown that EBV-driven cell proliferation requires the cellular transcription factor STAT3. EBV infection is rapidly followed by activation and increased expression of STAT3, which mediates relaxation of the intra-S phase cell-cycle checkpoint; this facilitates viral oncogene-driven cell proliferation. We now show that replication stress-associated DNA damage, which results from EBV infection, is detected by DDR. However, signaling downstream of ATR is impaired by STAT3, leading to relaxation of the intra-S phase checkpoint. We find that STAT3 interrupts ATR-to-Chk1 signaling by promoting loss of Claspin, a protein that assists ATR to phosphorylate Chk1. This loss of Claspin which ultimately facilitates cell proliferation is mediated by caspase 7, a protein that typically promotes cell death. Our findings demonstrate how STAT3, which is constitutively active in many human cancers, suppresses DDR, fundamental to tumorigenesis. This newly recognized role for STAT3 in attenuation of DDR, discovered in the context of EBV infection, is of broad interest as the biology of cell proliferation is central to both health and disease.

  7. GDNF facilitates differentiation of the adult dentate gyrus-derived neural precursor cells into astrocytes via STAT3

    International Nuclear Information System (INIS)

    Highlights: •GDNF has no effect on ADP proliferation and apoptosis. •GDNF increases ADP differentiation into astrocyte. •A specific inhibitor of STAT3 decreases the astrogliogenic effect of GDNF. •STAT3 knockdown by lentiviral shRNA vector also decreases the astrogliogenic effect of GDNF. •GDNF increases the phosphorylation of STAT3. -- Abstract: While the pro-neurogenic actions of antidepressants in the adult hippocampal dentate gyrus (DG) are thought to be one of the mechanisms through which antidepressants exert their therapeutic actions, antidepressants do not increase proliferation of neural precursor cells derived from the adult DG. Because previous studies showed that antidepressants increase the expression and secretion of glial cell line-derived neurotrophic factor (GDNF) in C6 glioma cells derived from rat astrocytes and GDNF increases neurogenesis in adult DG in vivo, we investigated the effects of GDNF on the proliferation, differentiation and apoptosis of cultured neural precursor cells derived from the adult DG. Data showed that GDNF facilitated the differentiation of neural precursor cells into astrocytes but had no effect on their proliferation or apoptosis. Moreover, GDNF increased the phosphorylation of STAT3, and both a specific inhibitor of STAT3 and lentiviral shRNA for STAT3 decreased their differentiation into astrocytes. Taken together, our findings suggest that GDNF facilitates astrogliogenesis from neural precursor cells in adult DG through activating STAT3 and that this action might indirectly affect neurogenesis

  8. GDNF facilitates differentiation of the adult dentate gyrus-derived neural precursor cells into astrocytes via STAT3

    Energy Technology Data Exchange (ETDEWEB)

    Boku, Shuken, E-mail: shuboku@med.hokudai.ac.jp [Department of Psychiatry, Hokkaido University Graduate School of Medicine, Sapporo (Japan); Nakagawa, Shin [Department of Psychiatry, Hokkaido University Graduate School of Medicine, Sapporo (Japan); Takamura, Naoki [Pharmaceutical Laboratories, Dainippon Sumitomo Pharma Co. Ltd., Osaka (Japan); Kato, Akiko [Department of Psychiatry, Hokkaido University Graduate School of Medicine, Sapporo (Japan); Takebayashi, Minoru [Department of Psychiatry, National Hospital Organization Kure Medical Center, Kure (Japan); Hisaoka-Nakashima, Kazue [Department of Pharmacology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima (Japan); Omiya, Yuki; Inoue, Takeshi; Kusumi, Ichiro [Department of Psychiatry, Hokkaido University Graduate School of Medicine, Sapporo (Japan)

    2013-05-17

    Highlights: •GDNF has no effect on ADP proliferation and apoptosis. •GDNF increases ADP differentiation into astrocyte. •A specific inhibitor of STAT3 decreases the astrogliogenic effect of GDNF. •STAT3 knockdown by lentiviral shRNA vector also decreases the astrogliogenic effect of GDNF. •GDNF increases the phosphorylation of STAT3. -- Abstract: While the pro-neurogenic actions of antidepressants in the adult hippocampal dentate gyrus (DG) are thought to be one of the mechanisms through which antidepressants exert their therapeutic actions, antidepressants do not increase proliferation of neural precursor cells derived from the adult DG. Because previous studies showed that antidepressants increase the expression and secretion of glial cell line-derived neurotrophic factor (GDNF) in C6 glioma cells derived from rat astrocytes and GDNF increases neurogenesis in adult DG in vivo, we investigated the effects of GDNF on the proliferation, differentiation and apoptosis of cultured neural precursor cells derived from the adult DG. Data showed that GDNF facilitated the differentiation of neural precursor cells into astrocytes but had no effect on their proliferation or apoptosis. Moreover, GDNF increased the phosphorylation of STAT3, and both a specific inhibitor of STAT3 and lentiviral shRNA for STAT3 decreased their differentiation into astrocytes. Taken together, our findings suggest that GDNF facilitates astrogliogenesis from neural precursor cells in adult DG through activating STAT3 and that this action might indirectly affect neurogenesis.

  9. Negative Regulation of STAT3 Protein-mediated Cellular Respiration by SIRT1 Protein

    DEFF Research Database (Denmark)

    Bernier, Michel; Paul, Rajib K; Martin-Montalvo, Alejandro;

    2011-01-01

    those of wild-type controls. Comparison of profiles of phospho-antibody array data indicated that the deletion of SirT1 was accompanied by constitutive activation of the pro-inflammatory NF-¿B pathway, which is key for STAT3 induction and increased cellular respiration in Sirt1-KO cells. Thus, SIRT1...... cells exhibited higher mitochondrial respiration as compared with wild-type MEFs. Two independent approaches, including ectopic expression of SIRT1 and siRNA-mediated knockdown of STAT3, led to reduction in intracellular ATP levels and increased lactate production in Sirt1-KO cells that were approaching...

  10. STAT3 and SOCS3 expression patterns during murine placenta development

    Directory of Open Access Journals (Sweden)

    S. San Martin

    2013-06-01

    Full Text Available Signal transducers and activators of transcription 3 (Stat3 has been identified as an important signal transducer in the invasive phenotype of the trophoblasts cells in in vitro studies. However, the in situ distribution and patterns of expression of this molecule in trophoblast cells during the development of the placenta are still under-elucidated. Mice uteri of gestational ages between 7 and 14 days of pregnancy (dop were fixed in methacarn and processed with immunoperoxidase techniques for detection of Stat3 and its phosphorylation at serine (p-ser727 residues, as well as the suppressor of cytokine signaling 3 (Socs3 expression. Stat3 was observed at 7 through 9 dop in both the antimesometrial and mesometrial deciduas, while continued immunoreactivity between 10 and 13 dop was seen only in the mesometrial decidua. In the placenta, Stat3 was detected in the cytotrophoblast cells of labyrinth and giant trophoblast cells between 10 and 14 dop. Immunoreactivity for Stat3 was also seen in trophoblast cells surrounding the maternal blood vessels. On days 10 and 11 of pregnancy, p-ser727 was detectable in the mesometrial decidua and in giant trophoblasts, while during 12-14 dop in the spongiotrophoblast region. In addition, Socs3 was immunodetected in maternal and placental tissues, principally in the giant trophoblast cells during the whole period of the study. The present in situ study shows the distribution of Stat3, its serine activation and Socs3 in different maternal and fetal compartments during murine placental development, thus further supporting the idea that they play a role during physiological placentation in mice. 

  11. Piperlongumine Blocks JAK2-STAT3 to Inhibit Collagen-Induced Platelet Reactivity Independent of Reactive Oxygen Species†

    OpenAIRE

    Hengjie Yuan; Houck, Katie L.; Ye Tian; Uddalak Bharadwaj; Ken Hull; Zhou Zhou; Mingzhao Zhu; Xiaoping Wu; David J Tweardy; Daniel Romo; Xiaoyun Fu; Yanjun Zhang; Jianning Zhang; Jing-fei Dong

    2015-01-01

    Background Piperlongumine (PL) is a compound isolated from the piper longum plant. It possesses anti-cancer activities through blocking the transcription factor STAT3 and by inducing reactive oxygen species (ROS) in cancer, but not normal cells. It also inhibits platelet aggregation induced by collagen, but the underlying mechanism is not known. Objective We conducted in vitro experiments to test the hypothesis that PL regulates a non-transcriptional activity of STAT3 to specifically reduce t...

  12. STAT3 upregulates miR-92a to inhibit RECK expression and to promote invasiveness of lung cancer cells

    OpenAIRE

    Lin, H-Y; Chiang, C-H; Hung, W-C

    2013-01-01

    Background: Signal transducer and activator of transcription 3 (STAT3) activation is frequently found in human lung cancer and is associated with increased metastasis and reduced survival. How STAT3 enhances invasiveness is unclear. Methods: The expression of microRNAs and target genes was measured by real-time RT–PCR. Protein level was studied by western blotting. Luciferase reporter assay was used to confirm the direct targeting of microRNAs. Gelatin zymography was used to study matrix meta...

  13. The Akt1/IL-6/STAT3 pathway regulates growth of lung tumor initiating cells.

    Science.gov (United States)

    Malanga, Donatella; De Marco, Carmela; Guerriero, Ilaria; Colelli, Fabiana; Rinaldo, Nicola; Scrima, Marianna; Mirante, Teresa; De Vitis, Claudia; Zoppoli, Pietro; Ceccarelli, Michele; Riccardi, Miriam; Ravo, Maria; Weisz, Alessandro; Federico, Antonella; Franco, Renato; Rocco, Gaetano; Mancini, Rita; Rizzuto, Antonia; Gulletta, Elio; Ciliberto, Gennaro; Viglietto, Giuseppe

    2015-12-15

    Here we report that the PI3K/Akt1/IL-6/STAT3 signalling pathway regulates generation and stem cell-like properties of Non-Small Cell Lung Cancer (NSCLC) tumor initiating cells (TICs). Mutant Akt1, mutant PIK3CA or PTEN loss enhances formation of lung cancer spheroids (LCS), self-renewal, expression of stemness markers and tumorigenic potential of human immortalized bronchial cells (BEAS-2B) whereas Akt inhibition suppresses these activities in established (NCI-H460) and primary NSCLC cells. Matched microarray analysis of Akt1-interfered cells and LCSs identified IL-6 as a critical target of Akt signalling in NSCLC TICs. Accordingly, suppression of Akt in NSCLC cells decreases IL-6 levels, phosphorylation of IkK and IkB, NF-kB transcriptional activity, phosphorylation and transcriptional activity of STAT3 whereas active Akt1 up-regulates them. Exposure of LCSs isolated from NSCLC cells to blocking anti-IL-6 mAbs, shRNA to IL-6 receptor or to STAT3 markedly reduces the capability to generate LCSs, to self-renew and to form tumors, whereas administration of IL-6 to Akt-interfered cells restores the capability to generate LCSs. Finally, immunohistochemical studies in NSCLC patients demonstrated a positive correlative trend between activated Akt, IL-6 expression and STAT3 phosphorylation (n = 94; p cells in NSCLC.

  14. Expression profiling in transgenic FVB/N embryonic stem cells overexpressing STAT3

    Directory of Open Access Journals (Sweden)

    Yokota Takashi

    2008-05-01

    Full Text Available Abstract Background The transcription factor STAT3 is a downstream target of the LIF signalling cascade. LIF signalling or activation is sufficient to maintain embryonic stem (ES cells in an undifferentiated and pluripotent state. To further investigate the importance of STAT3 in the establishment of ES cells we have in a first step derived stable pluripotent embryonic stem cells from transgenic FVB mice expressing a conditional tamoxifen dependent STAT3-MER fusion protein. In a second step, STAT3-MER overexpressing cells were used to identify STAT3 pathway-related genes by expression profiling in order to identify new key-players involved in maintenance of pluripotency in ES cells. Results Transgenic STAT3-MER blastocysts yielded pluripotent germline-competent ES cells at a high frequency in the absence of LIF when established in tamoxifen-containing medium. Expression profiling of tamoxifen-induced transgenic FVB ES cell lines revealed a set of 26 genes that were markedly up- or down-regulated when compared with wild type cells. The expression of four of the up-regulated genes (Hexokinase II, Lefty2, Pramel7, PP1rs15B was shown to be restricted to the inner cell mass (ICM of the blastocysts. These differentially expressed genes represent potential candidates for the maintenance of pluripotency of ES cells. We finally overexpressed two candidate genes, Pem/Rhox5 and Pramel7, in ES cells and demonstrated that their overexpression is sufficient for the maintenance of expression of ES cell markers as well as of the typical morphology of pluripotent ES cells in absence of LIF. Conclusion Overexpression of STAT3-MER in the inner cell mass of blastocyst facilitates the establishment of ES cells and induces the upregulation of potential candidate genes involved in the maintenance of pluripotency. Two of them, Pem/Rhox5 and Pramel7, when overexpressed in ES cells are able to maintain the embryonic stem cells in a pluripotent state in a LIF independent

  15. Dietary cocoa inhibits colitis associated cancer: a crucial involvement of the IL-6/STAT3 pathway.

    Science.gov (United States)

    Saadatdoust, Zeinab; Pandurangan, Ashok Kumar; Ananda Sadagopan, Suresh Kumar; Mohd Esa, Norhaizan; Ismail, Amin; Mustafa, Mohd Rais

    2015-12-01

    Patients with inflammatory bowel disease (IBD) are at increased risk for developing ulcerative colitis-associated colorectal cancer (CRC). The interleukin-6 (IL-6)/signal transducer and activator of transcription (STAT)-3 signaling regulates survival and proliferation of intestinal epithelial cells and play an important role in the pathogenesis of IBD and CRC. Cocoa is enriched with polyphenols that known to possess antioxidant, anti-inflammatory and antitumor activities. Here, we explored the antitumor effects and mechanisms of cocoa diet on colitis-associated cancer (CAC) using the azoxymethane/dextran sulfate sodium model, with a particular focus on whether cocoa exerts its anticancer effect through the IL-6/STAT3 pathway. We found that cocoa significantly decreased the tumor incidence and size in CAC-induced mice. In addition to inhibiting proliferation of tumor epithelial cells, cocoa suppressed colonic IL-6 expression and subsequently activation of STAT3. Thus, our findings demonstrated that cocoa diet suppresses CAC tumorigenesis, and its antitumor effect is partly mediated by limiting IL-6/STAT3 activation. In addition, cocoa induces apoptosis by increased the expressions of Bax and caspase 3 and decreased Bcl-xl. Thus, we conclude that cocoa may be a potential agent in the prevention and treatment of CAC. PMID:26355019

  16. STAT3 signaling pathway is necessary for cell survival and tumorsphere forming capacity in ALDH+/CD133+ stem cell-like human colon cancer cells

    International Nuclear Information System (INIS)

    Highlights: ► The phosphorylated or activated form of STAT3 was expressed in colon cancer stem-like cells. ► STAT3 inhibitor, FLLL32 inhibits P-STAT3 and STAT3 target genes in colon cancer stem-like cells. ► Inhibition of STAT3 resulted in decreased cell viability and reduced numbers of tumorspheres. ► STAT3 is required for survival and tumorsphere forming capacity in colon cancer stem-like cells. ► Targeting STAT3 in cancer stem-like cells may offer a novel treatment approach for colon cancer. -- Abstract: Persistent activation of Signal Transducers and Activators of Transcription 3 (STAT3) is frequently detected in colon cancer. Increasing evidence suggests the existence of a small population of colon cancer stem or cancer-initiating cells may be responsible for tumor initiation, metastasis, and resistance to chemotherapy and radiation. Whether STAT3 plays a role in colon cancer-initiating cells and the effect of STAT3 inhibition is still unknown. Flow cytometry was used to isolate colon cancer stem-like cells from three independent human colon cancer cell lines characterized by both aldehyde dehydrogenase (ALDH)-positive and CD133-positive subpopulation (ALDH+/CD133+). The effects of STAT3 inhibition in colon cancer stem-like cells were examined. The phosphorylated or activated form of STAT3 was expressed in colon cancer stem-like cells and was reduced by a STAT3-selective small molecular inhibitor, FLLL32. FLLL32 also inhibited the expression of potential STAT3 downstream target genes in colon cancer stem-like cells including survivin, Bcl-XL, as well as Notch-1, -3, and -4, which may be involved in stem cell function. Furthermore, FLLL32 inhibited cell viability and tumorsphere formation as well as induced cleaved caspase-3 in colon cancer stem-like cells. FLLL32 is more potent than curcumin as evidenced with lower IC50 in colon cancer stem-like cells. In summary, our results indicate that STAT3 is a novel therapeutic target in colon cancer stem

  17. STAT3 signaling pathway is necessary for cell survival and tumorsphere forming capacity in ALDH{sup +}/CD133{sup +} stem cell-like human colon cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Li, E-mail: lin.796@osu.edu [Center for Childhood Cancer, The Research Institute at Nationwide Children' s Hospital, Department of Pediatrics, Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43205 (United States); Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030 (China); Fuchs, James; Li, Chenglong [Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, OH 43210 (United States); Olson, Veronica [Center for Childhood Cancer, The Research Institute at Nationwide Children' s Hospital, Department of Pediatrics, Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43205 (United States); Bekaii-Saab, Tanios [Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43210 (United States); Lin, Jiayuh, E-mail: lin.674@osu.edu [Center for Childhood Cancer, The Research Institute at Nationwide Children' s Hospital, Department of Pediatrics, Internal Medicine, College of Medicine, The Ohio State University, Columbus, OH 43205 (United States)

    2011-12-16

    Highlights: Black-Right-Pointing-Pointer The phosphorylated or activated form of STAT3 was expressed in colon cancer stem-like cells. Black-Right-Pointing-Pointer STAT3 inhibitor, FLLL32 inhibits P-STAT3 and STAT3 target genes in colon cancer stem-like cells. Black-Right-Pointing-Pointer Inhibition of STAT3 resulted in decreased cell viability and reduced numbers of tumorspheres. Black-Right-Pointing-Pointer STAT3 is required for survival and tumorsphere forming capacity in colon cancer stem-like cells. Black-Right-Pointing-Pointer Targeting STAT3 in cancer stem-like cells may offer a novel treatment approach for colon cancer. -- Abstract: Persistent activation of Signal Transducers and Activators of Transcription 3 (STAT3) is frequently detected in colon cancer. Increasing evidence suggests the existence of a small population of colon cancer stem or cancer-initiating cells may be responsible for tumor initiation, metastasis, and resistance to chemotherapy and radiation. Whether STAT3 plays a role in colon cancer-initiating cells and the effect of STAT3 inhibition is still unknown. Flow cytometry was used to isolate colon cancer stem-like cells from three independent human colon cancer cell lines characterized by both aldehyde dehydrogenase (ALDH)-positive and CD133-positive subpopulation (ALDH{sup +}/CD133{sup +}). The effects of STAT3 inhibition in colon cancer stem-like cells were examined. The phosphorylated or activated form of STAT3 was expressed in colon cancer stem-like cells and was reduced by a STAT3-selective small molecular inhibitor, FLLL32. FLLL32 also inhibited the expression of potential STAT3 downstream target genes in colon cancer stem-like cells including survivin, Bcl-XL, as well as Notch-1, -3, and -4, which may be involved in stem cell function. Furthermore, FLLL32 inhibited cell viability and tumorsphere formation as well as induced cleaved caspase-3 in colon cancer stem-like cells. FLLL32 is more potent than curcumin as evidenced with lower

  18. Hedyotis diffusa Willd inhibits colorectal cancer growth in vivo via inhibition of STAT3 signaling pathway.

    Science.gov (United States)

    Cai, Qiaoyan; Lin, Jiumao; Wei, Lihui; Zhang, Ling; Wang, Lili; Zhan, Youzhi; Zeng, Jianwei; Xu, Wei; Shen, Aling; Hong, Zhenfeng; Peng, Jun

    2012-01-01

    Signal Transducer and Activator of Transcription 3 (STAT3), a common oncogenic mediator, is constitutively activated in many types of human cancers; therefore it is a major focus in the development of novel anti-cancer agents. Hedyotis diffusa Willd has been used as a major component in several Chinese medicine formulas for the clinical treatment of colorectal cancer (CRC). However, the precise mechanism of its anti-tumor activity remains largely unclear. Using a CRC mouse xenograft model, in the present study we evaluated the effect of the ethanol extract of Hedyotis diffusa Willd (EEHDW) on tumor growth in vivo and investigated the underlying molecular mechanisms. We found that EEHDW reduced tumor volume and tumor weight, but had no effect on body weight gain in CRC mice, demonstrating that EEHDW can inhibit CRC growth in vivo without apparent adverse effect. In addition, EEHDW treatment suppressed STAT3 phosphorylation in tumor tissues, which in turn resulted in the promotion of cancer cell apoptosis and inhibition of proliferation. Moreover, EEHDW treatment altered the expression pattern of several important target genes of the STAT3 signaling pathway, i.e., decreased expression of Cyclin D1, CDK4 and Bcl-2 as well as up-regulated p21 and Bax. These results suggest that suppression of the STAT3 pathway might be one of the mechanisms by which EEHDW treats colorectal cancer. PMID:22754353

  19. Ratios of Four STAT3 Splice Variants in Human Eosinophils and Diffuse Large B Cell Lymphoma Cells.

    Directory of Open Access Journals (Sweden)

    Keren B Turton

    Full Text Available Signal transducer and activator of transcription 3 (STAT3 is a key mediator of leukocyte differentiation and proliferation. The 3' end of STAT3 transcripts is subject to two alternative splicing events. One results in either full-length STAT3α or in STAT3β, which lacks part of the C-terminal transactivation domain. The other is at a tandem donor (5' splice site and results in the codon for Ser-701 being included (S or excluded (ΔS. Despite the proximity of Ser-701 to the site of activating phosphorylation at Tyr-705, ΔS/S splicing has barely been studied. Sequencing of cDNA from purified eosinophils revealed the presence of four transcripts (S-α, ΔS-α, S-β, and ΔS-β rather than the three reported in publically available databases from which ΔS-β is missing. To gain insight into regulation of the two alternative splicing events, we developed a quantitative(q PCR protocol to compare transcript ratios in eosinophils in which STAT3 is upregulated by cytokines, activated B cell diffuse large B cell Lymphoma (DLBCL cells in which STAT3 is dysregulated, and in germinal center B cell-like DLBCL cells in which it is not. With the exception of one line of activated B cell DLCBL cells, the four variants were found in roughly the same ratios despite differences in total levels of STAT3 transcripts. S-α was the most abundant, followed by S-β. ΔS-α and ΔS-β together comprised 15.6 ± 4.0 % (mean ± SD, n = 21 of the total. The percentage of STAT3β variants that were ΔS was 1.5-fold greater than of STAT3α variants that were ΔS. Inspection of Illumina's "BodyMap" RNA-Seq database revealed that the ΔS variant accounts for 10-26 % of STAT3 transcripts across 16 human tissues, with less variation than three other genes with the identical tandem donor splice site sequence. Thus, it seems likely that all cells contain the S-α, ΔS-α, S-β, and ΔS-β variants of STAT3.

  20. Ratios of Four STAT3 Splice Variants in Human Eosinophils and Diffuse Large B Cell Lymphoma Cells.

    Science.gov (United States)

    Turton, Keren B; Annis, Douglas S; Rui, Lixin; Esnault, Stephane; Mosher, Deane F

    2015-01-01

    Signal transducer and activator of transcription 3 (STAT3) is a key mediator of leukocyte differentiation and proliferation. The 3' end of STAT3 transcripts is subject to two alternative splicing events. One results in either full-length STAT3α or in STAT3β, which lacks part of the C-terminal transactivation domain. The other is at a tandem donor (5') splice site and results in the codon for Ser-701 being included (S) or excluded (ΔS). Despite the proximity of Ser-701 to the site of activating phosphorylation at Tyr-705, ΔS/S splicing has barely been studied. Sequencing of cDNA from purified eosinophils revealed the presence of four transcripts (S-α, ΔS-α, S-β, and ΔS-β) rather than the three reported in publically available databases from which ΔS-β is missing. To gain insight into regulation of the two alternative splicing events, we developed a quantitative(q) PCR protocol to compare transcript ratios in eosinophils in which STAT3 is upregulated by cytokines, activated B cell diffuse large B cell Lymphoma (DLBCL) cells in which STAT3 is dysregulated, and in germinal center B cell-like DLBCL cells in which it is not. With the exception of one line of activated B cell DLCBL cells, the four variants were found in roughly the same ratios despite differences in total levels of STAT3 transcripts. S-α was the most abundant, followed by S-β. ΔS-α and ΔS-β together comprised 15.6 ± 4.0 % (mean ± SD, n = 21) of the total. The percentage of STAT3β variants that were ΔS was 1.5-fold greater than of STAT3α variants that were ΔS. Inspection of Illumina's "BodyMap" RNA-Seq database revealed that the ΔS variant accounts for 10-26 % of STAT3 transcripts across 16 human tissues, with less variation than three other genes with the identical tandem donor splice site sequence. Thus, it seems likely that all cells contain the S-α, ΔS-α, S-β, and ΔS-β variants of STAT3.

  1. Study on the effect of STAT3 in promotion of proliferation of breast cancer cells with bisphenol A%STAT3在双酚A促乳腺癌细胞增殖中的作用研究

    Institute of Scientific and Technical Information of China (English)

    张巍; 谭岩; 方艳秋

    2013-01-01

    目的:探讨STAT3在双酚A促乳腺癌MCF-7细胞增殖中的作用,为研究双酚A诱导乳腺癌的确切机制提供依据.方法:采用Western blot检测双酚A处理乳腺癌MCF-7细胞24h和48 h后STAT3的表达情况,采用MTT法检测RNA干扰技术抑制STAT3后双酚A对乳腺癌细胞增殖的影响.结果:Western blot结果表明,STAT3在1μM双酚A作用48 h后其诱导表达最明显(P<0.05);通过对照研究筛选出有效的干扰片段,能显著抑制STAT3基因的表达,当干扰片段抑制了STAT3基因表达后,双酚A未能抑制STAT3的MCF-7细胞发生增殖效应(P>0.05).结论:在双酚A诱导乳腺癌细胞的增殖作用中,STAT3的活化和活化后的信号传导是非常重要的一个环节.%Objective:To explore the effect of STAT3 in promotion of proliferation of breast cancer cells with bisphenol A,and research the exact machanism of breast cancer induced by bisphenol A.Methods:Western blot was used to detect the expressions of STAT3 at 24 and 48 hours after treating breast cancer MCF-7 cells with bisphenol A,MTT method was used to detect the effect of bisphenol A on proliferation of breast cells after suppressing STAT3 with RNA interfering technique.Results:The results of Western blot showed that the inducing effect of STAT3 after treated with 1 μM bisphenol A for 48 hours was the most obvious (P < 0.05) ; a case-control study was performed to screen out effective interfering fragments,which suppressed the expression of STAT3 gene significantly,when interfering fragments suppressed expression of STAT3 gene,bisphenol A didnt suppress the proliferative effect of STAT3 on breast cancer MCF-7 cells (P >0.05).Conclusion:The activation of STAT3 and signal transduction after activation is a very important link in proliferative effect of breast cancer cells induced by bisphenol A.

  2. The prognostic significance of STAT3 in invasive breast cancer: analysis of protein and mRNA expressions in large cohorts.

    Science.gov (United States)

    Aleskandarany, Mohammed A; Agarwal, Devika; Negm, Ola H; Ball, Graham; Elmouna, Ahmed; Ashankyty, Ibraheem; Nuglozeh, Edem; Fazaludeen, Mohammad F; Diez-Rodriguez, Maria; Nolan, Christopher C; Tighe, Patrick J; Green, Andrew R; Ellis, Ian O; Rakha, Emad A

    2016-02-01

    Signal transducer and activator of transcription (STAT) transcription factors family are involved in diverse cellular biological functions. Reports regarding the prognostic impact of STAT3 expression in breast cancer (BC) are variable whether being a factor of poor or good prognosis. Immunohistochemical expression of phospho-STAT3 (pSTAT3) was studied in large series of invasive BC (n = 1270). pSTAT3 and STAT3 were quantified using reverse phase protein array (RPPA) on proteins extracted from macro-dissected FFPE tissues (n = 49 cases). STAT3 gene expression in the METABRIC cohort was also investigated. STAT3 gene expression prognostic impact was externally validated using the online BC gene expression data (n = 26 datasets, 4.177 patients). pSTAT3 was expressed in the nuclei and cytoplasm of invasive BC cells. Nuclear pSTAT3 overexpression was positively associated with smaller tumour size, lower grade, good NPI, negative lymphovascular invasion (LVI), ER+, PgR+, p53-, HER2-, and low Ki67LI and an improved breast cancer-specific survival (BCSS), independently of other factors. On RPPA, the mean pSTAT3 and STAT3 expressions were higher in ER+, PgR+, and smaller size tumours. Higher STAT3 transcripts in the METABRIC cohort were observed in cases with favourable prognostic criteria and as well as improved BCSS within the whole cohort, ER+ cohort with and without hormonal therapy, and ER- cohort including those who did not receive adjuvant chemotherapy. Pooled STAT3 gene expression data in the external validation cohort showed an association with improved patients' outcome (P < 0.001, HR = 0.84, 95 % CI 0.79-0.90). Results of this study suggest nuclear localisation of pSTAT3 as favourable prognostic marker in invasive BC, results re-enforced by analysis of STAT3 gene expression data. This good prognostic advantage was maintained in patients who received and who did not receive adjuvant therapy. Therefore, STAT3 could have context-dependent molecular roles of in BC

  3. New role of JAK2/STAT3 signaling in endothelial cell oxidative stress injury and protective effect of melatonin.

    Directory of Open Access Journals (Sweden)

    Weixun Duan

    Full Text Available Previous studies have shown that the JAK2/STAT3 signaling pathway plays a regulatory role in cellular oxidative stress injury (OSI. In this study, we explored the role of the JAK2/STAT3 signaling pathway in hydrogen peroxide (H2O2-induced OSI and the protective effect of melatonin against (H2O2-induced injury in human umbilical vein endothelial cells (HUVECs. AG490 (a specific inhibitor of the JAK2/STAT3 signaling pathway and JAK2 siRNA were used to manipulate JAK2/STAT3 activity, and the results showed that AG490 and JAK2 siRNA inhibited OSI and the levels of p-JAK2 and p-STAT3. HUVECs were then subjected to H2O2 in the absence or presence of melatonin, the main secretory product of the pineal gland. Melatonin conferred a protective effect against H2O2, which was evidenced by improvements in cell viability, adhesive ability and migratory ability, decreases in the apoptotic index and reactive oxygen species (ROS production and several biochemical parameters in HUVECs. Immunofluorescence and Western blotting showed that H2O2 treatment increased the levels of p-JAK2, p-STAT3, Cytochrome c, Bax and Caspase3 and decreased the levels of Bcl2, whereas melatonin treatment partially reversed these effects. We, for the first time, demonstrate that the inhibition of the JAK2/STAT3 signaling pathway results in a protective effect against endothelial OSI. The protective effects of melatonin against OSI, at least partially, depend upon JAK2/STAT3 inhibition.

  4. SPARC expression induces cell cycle arrest via STAT3 signaling pathway in medulloblastoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Chetty, Chandramu [Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, One Illini Drive, Peoria, IL-61605 (United States); Dontula, Ranadheer [Section of Hematology/Oncology, Department of Medicine, University of Illinois College of Medicine at Chicago, 840 South Wood Street, Suite 820-E, Chicago, IL-60612 (United States); Ganji, Purnachandra Nagaraju [Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, One Illini Drive, Peoria, IL-61605 (United States); Gujrati, Meena [Department of Pathology, University of Illinois College of Medicine at Peoria, One Illini Drive, Peoria, IL-61605 (United States); Lakka, Sajani S., E-mail: slakka@uic.edu [Section of Hematology/Oncology, Department of Medicine, University of Illinois College of Medicine at Chicago, 840 South Wood Street, Suite 820-E, Chicago, IL-60612 (United States)

    2012-01-13

    Highlights: Black-Right-Pointing-Pointer Ectopic expression of SPARC impaired cell proliferation in medulloblastoma cells. Black-Right-Pointing-Pointer SPARC expression induces STAT3 mediated cell cycle arrest in medulloblastoma cells. Black-Right-Pointing-Pointer SPARC expression significantly inhibited pre-established tumor growth in nude-mice. -- Abstract: Dynamic cell interaction with ECM components has profound influence in cancer progression. SPARC is a component of the ECM, impairs the proliferation of different cell types and modulates tumor cell aggressive features. We previously reported that SPARC expression significantly impairs medulloblastoma tumor growth in vivo. In this study, we demonstrate that expression of SPARC inhibits medulloblastoma cell proliferation. MTT assay indicated a dose-dependent reduction in tumor cell proliferation in adenoviral mediated expression of SPARC full length cDNA (Ad-DsRed-SP) in D425 and UW228 cells. Flow cytometric analysis showed that Ad-DsRed-SP-infected cells accumulate in the G2/M phase of cell cycle. Further, immunoblot and immunoprecipitation analyses revealed that SPARC induced G2/M cell cycle arrest was mediated through inhibition of the Cyclin-B-regulated signaling pathway involving p21 and Cdc2 expression. Additionally, expression of SPARC decreased STAT3 phosphorylation at Tyr-705; constitutively active STAT3 expression reversed SPARC induced G2/M arrest. Ad-DsRed-SP significantly inhibited the pre-established orthotopic tumor growth and tumor volume in nude-mice. Immunohistochemical analysis of tumor sections from mice treated with Ad-DsRed-SP showed decreased immunoreactivity for pSTAT3 and increased immunoreactivity for p21 compared to tumor section from mice treated with mock and Ad-DsRed. Taken together our studies further reveal that STAT3 plays a key role in SPARC induced G2/M arrest in medulloblastoma cells. These new findings provide a molecular basis for the mechanistic understanding of the

  5. Dissecting functions of the N-terminal domain and GAS-site recognition in STAT3 nuclear trafficking.

    Science.gov (United States)

    Martincuks, Antons; Fahrenkamp, Dirk; Haan, Serge; Herrmann, Andreas; Küster, Andrea; Müller-Newen, Gerhard

    2016-08-01

    Signal transducer and activator of transcription 3 (STAT3) is a ubiquitous transcription factor involved in many biological processes, including hematopoiesis, inflammation and cancer progression. Cytokine-induced gene transcription greatly depends on tyrosine phosphorylation of STAT3 on a single tyrosine residue with subsequent nuclear accumulation and specific DNA sequence (GAS) recognition. In this study, we analyzed the roles of the conserved STAT3 N-terminal domain (NTD) and GAS-element binding ability of STAT3 in nucleocytoplasmic trafficking. Our results demonstrate the nonessential role of GAS-element recognition for both cytokine-induced and basal nuclear import of STAT3. Substitution of five key amino acids within the DNA-binding domain rendered STAT3 unable to bind to GAS-elements while still maintaining the ability for nuclear localization. In turn, deletion of the NTD markedly decreased nuclear accumulation upon IL-6 treatment resulting in a prolonged accumulation of phosphorylated dimers in the cytoplasm, at the same time preserving specific DNA recognition ability of the truncation mutant. Observed defect in nuclear localization could not be explained by flawed importin-α binding, since both wild-type and NTD deletion mutant of STAT3 could precipitate both full-length and autoinhibitory domain (∆IBB) deletion mutants of importin-α5, as well as ∆IBB-α3 and ∆IBB-α7 isoforms independently of IL-6 stimulation. Despite its inability to translocate to the nucleus upon IL-6 stimulation, the NTD lacking mutant still showed nuclear accumulation in resting cells similar to wild-type upon inhibition of nuclear export by leptomycin B. At the same time, blocking the nuclear export pathway could not rescue cytoplasmic trapping of phosphorylated STAT3 molecules without NTD. Moreover, STAT3 mutant with dysfunctional SH2 domain (R609Q) also localized in the nucleus of unstimulated cells after nuclear export blocking, while upon cytokine treatment the

  6. NF-κB/STAT3/PI3K signaling crosstalk in iMycEμ B lymphoma

    Directory of Open Access Journals (Sweden)

    Kim Joong-Su

    2010-04-01

    Full Text Available Abstract Background Myc is a well known driver of lymphomagenesis, and Myc-activating chromosomal translocation is the recognized hallmark of Burkitt lymphoma, an aggressive form of non-Hodgkin's lymphoma. We developed a model that mimics this translocation event by inserting a mouse Myc cDNA gene into the immunoglobulin heavy chain locus, just upstream of the intronic Eμ enhancer. These mice, designated iMycEμ, readily develop B-cell lymphoma. To study the mechanism of Myc-induced lymphoma, we analyzed signaling pathways in lymphoblastic B-cell lymphomas (LBLs from iMycEμ mice, and an LBL-derived cell line, iMycEμ-1. Results Nuclear factor-κB (NF-κB and signal transducer and activator of transcription 3 (STAT3 were constitutively activated in iMycEμ mice, not only in LBLs but also in the splenic B-lymphocytes of young animals months before tumors developed. Moreover, inhibition of either transcription factor in iMycEμ-1 cells suppressed growth and caused apoptosis, and the abrogation of NF-κB activity reduced DNA binding by both STAT3 and Myc, as well as Myc expression. Inhibition of STAT3 signaling eliminated the activity of both NF-κB and Myc, and resulted in a corresponding decrease in the level of Myc. Thus, in iMycEμ-1 cells NF-κB and STAT3 are co-dependent and can both regulate Myc. Consistent with this, NF-κB and phosphorylated STAT3 were physically associated with one another. In addition, LBLs and iMycEμ-1 cells also showed constitutive AKT phosphorylation. Blocking AKT activation by inhibiting PI3K reduced iMycEμ-1 cell proliferation and caused apoptosis, via downregulation of NF-κB and STAT3 activity and a reduction of Myc levels. Co-treatment with NF-κB, STAT3 or/and PI3K inhibitors led to additive inhibition of iMycEμ-1 cell proliferation, suggesting that these signaling pathways converge. Conclusions Our findings support the notion that constitutive activation of NF-κB and STAT3 depends on upstream signaling

  7. STAT3在新型肠道病毒71型(EV71)感染和复制中的作用初步研究%Effects of STAT3 on enterovirus 71 (EV71) infection and replication

    Institute of Scientific and Technical Information of China (English)

    王艳; 卞良; 刘晴晴; 熊鹰; 李泽阳; 龙健儿

    2015-01-01

    目的 研究STAT3 (signal transducer and activator of transcription 3)对新型肠道病毒71型(enterovirus 71,EV71)感染及复制的影响.方法 观察EV71感染横纹肌肉瘤细胞后STAT3的动态表达;利用慢病毒载体下调或过表达STAT3技术,观察细胞在改变STAT3表达后,对EV71感染细胞后病毒VP1表达、形成蚀斑和病毒滴度的影响,研究STAT3对EV71感染和复制的影响.结果 EV71感染可明显下调细胞STAT3-Tyr705磷酸化(p-STAT3)水平.在STAT3表达稳定下调的细胞中,p-STAT3水平也下调,这有利于EV71病毒感染和复制.而过表达STAT3的细胞内,p-STAT3水平也上调,对EV71感染和复制的效应与上述STAT3下调的结果相反.免疫共聚焦和蚀斑分析发现高表达p-STAT3的细胞不易被EV71感染.结论 EV71感染可明显下调p-STAT3水平,并促进病毒的复制.STAT3影响EV71的感染和复制,可能主要通过STAT3的磷酸化水平影响细胞对病毒的易感性.

  8. BCL3 exerts an oncogenic function by regulating STAT3 in human cervical cancer

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    Zhao H

    2016-10-01

    Full Text Available Hu Zhao,1 Wuliang Wang,1 Qinghe Zhao,1 Guiming Hu,2 Kehong Deng,1 Yuling Liu1 1Department of Gynecology and Obstetrics, 2Department of Pathology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, People’s Republic of China Abstract: Aberrant expression of oncogenes and/or tumor suppressors play a fundamental effect on the pathogenesis and tumorigenicity of cervical cancer (CC. B-cell CLL/lymphoma 3 (BCL3 was previously found to be a putative proto-oncogene in human cancers and regulated signal transducer and activator of transcription 3 (STAT3, a critical oncogene, in CC cell line. However, its expression status, clinical significance and biological functions in CC remain largely unclear. The expressions of BCL3 and STAT3 in CC specimens were determined by immunohistochemistry. MTT, colony formation assays and flow cytometry analysis were carried out to test proliferation and cell cycle of CC cells. Here, the levels of BCL3 were overexpressed in CC compared to adjacent cervical tissues. Furthermore, high levels of BCL3 protein were confirmed by immunoblotting in CC cells as compared with normal cervical epithelial cells. The positive expression of BCL3 was correlated with adverse prognostic features and reduced survival rate. In addition, BCL3 regulated STAT3 abundance in CC cells. STAT3 was found to be upregulated and positively correlated with BCL3 expression in CC specimens. BCL3 overexpression resulted in prominent increased proliferation and cell cycle progression in Hela cells. By contrast, inhibition of BCL3 in CaSki cells remarkably suppressed proliferative ability and cell cycle progression. In vivo studies showed that knockdown of BCL3 inhibited tumor growth of CC in mice xenograft model. Notably, we confirmed that STAT3 mediated the oncogenic roles of BCL3 in CC. In conclusion, we suggest that BCL3 serves as an oncogene in CC by modulating proliferation and cell cycle progression, and its oncogenic effect is

  9. Inhibitory effect of a tyrosine-fructose Maillard reaction product, 2,4-bis(p-hydroxyphenyl-2-butenal on amyloid-β generation and inflammatory reactions via inhibition of NF-κB and STAT3 activation in cultured astrocytes and microglial BV-2 cells

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    Choi Im Seup

    2011-10-01

    Full Text Available Abstract Background Amyloidogenesis is linked to neuroinflammation. The tyrosine-fructose Maillard reaction product, 2,4-bis(p-hydroxyphenyl-2-butenal, possesses anti-inflammatory properties in cultured macrophages, and in an arthritis animal model. Because astrocytes and microglia are responsible for amyloidogenesis and inflammatory reactions in the brain, we investigated the anti-inflammatory and anti-amyloidogenic effects of 2,4-bis(p-hydroxyphenyl-2-butenal in lipopolysaccharide (LPS-stimulated astrocytes and microglial BV-2 cells. Methods Cultured astrocytes and microglial BV-2 cells were treated with LPS (1 μg/ml for 24 h, in the presence (1, 2, 5 μM or absence of 2,4-bis(p-hydroxyphenyl-2-butenal, and harvested. We performed molecular biological analyses to determine the levels of inflammatory and amyloid-related proteins and molecules, cytokines, Aβ, and secretases activity. Nuclear factor-kappa B (NF-κB DNA binding activity was determined using gel mobility shift assays. Results We found that 2,4-bis(p-hydroxyphenyl-2-butenal (1, 2, 5 μM suppresses the expression of inducible nitric oxide synthase (iNOS and cyclooxygenase-2 (COX-2 as well as the production of nitric oxide (NO, reactive oxygen species (ROS, tumor necrosis factor-α (TNF-α, and interleukin-1β (IL-1β in LPS (1 μg/ml-stimulated astrocytes and microglial BV-2 cells. Further, 2,4-bis(p-hydroxyphenyl-2-butenal inhibited the transcriptional and DNA binding activity of NF-κB--a transcription factor that regulates genes involved in neuroinflammation and amyloidogenesis via inhibition of IκB degradation as well as nuclear translocation of p50 and p65. Consistent with the inhibitory effect on inflammatory reactions, 2,4-bis(p-hydroxyphenyl-2-butenal inhibited LPS-elevated Aβ42 levels through attenuation of β- and γ-secretase activities. Moreover, studies using signal transducer and activator of transcription 3 (STAT3 siRNA and a pharmacological inhibitor showed that 2

  10. Piperlongumine Blocks JAK2-STAT3 to Inhibit Collagen-Induced Platelet Reactivity Independent of Reactive Oxygen Species†

    Science.gov (United States)

    Yuan, Hengjie; Houck, Katie L.; Tian, Ye; Bharadwaj, Uddalak; Hull, Ken; Zhou, Zhou; Zhou, Mingzhao; Wu, Xiaoping; Tweardy, David J.; Romo, Daniel; Fu, Xiaoyun; Zhang, Yanjun; Zhang, Jianning; Dong, Jing-fei

    2015-01-01

    Background Piperlongumine (PL) is a compound isolated from the piper longum plant. It possesses anti-cancer activities through blocking the transcription factor STAT3 and by inducing reactive oxygen species (ROS) in cancer, but not normal cells. It also inhibits platelet aggregation induced by collagen, but the underlying mechanism is not known. Objective We conducted in vitro experiments to test the hypothesis that PL regulates a non-transcriptional activity of STAT3 to specifically reduce the reactivity of human platelets to collagen. Results PL dose-dependently blocked collagen-induced platelet aggregation, calcium influx, CD62p expression and thrombus formation on collagen with a maximal inhibition at 100 μM. It reduced platelet microvesiculation induced by collagen. PL blocked the activation of JAK2 and STAT3 in collagen-stimulated platelets. This inhibitory effect was significantly reduced in platelets pretreated with a STAT3 inhibitor. Although PL induced ROS production in platelets; quenching ROS using excessive reducing agents: 20 μM GSH and 0.5 mM L-Cysteine, did not block the inhibitory effects. The NADPH oxidase inhibitor Apocynin also had no effect. Conclusions PL inhibited collagen-induced platelet reactivity by targeting the JAK2-STAT3 pathway. We also provide experimental evidence that PL and collagen induce different oxidants that have differential effects on platelets. Studying these differential effects may uncover new mechanisms of regulating platelet functions by oxidants in redox signals. PMID:26645674

  11. Piperlongumine Blocks JAK2-STAT3 to Inhibit Collagen-Induced Platelet Reactivity Independent of Reactive Oxygen Species.

    Directory of Open Access Journals (Sweden)

    Hengjie Yuan

    Full Text Available Piperlongumine (PL is a compound isolated from the piper longum plant. It possesses anti-cancer activities through blocking the transcription factor STAT3 and by inducing reactive oxygen species (ROS in cancer, but not normal cells. It also inhibits platelet aggregation induced by collagen, but the underlying mechanism is not known.We conducted in vitro experiments to test the hypothesis that PL regulates a non-transcriptional activity of STAT3 to specifically reduce the reactivity of human platelets to collagen.PL dose-dependently blocked collagen-induced platelet aggregation, calcium influx, CD62p expression and thrombus formation on collagen with a maximal inhibition at 100 μM. It reduced platelet microvesiculation induced by collagen. PL blocked the activation of JAK2 and STAT3 in collagen-stimulated platelets. This inhibitory effect was significantly reduced in platelets pretreated with a STAT3 inhibitor. Although PL induced ROS production in platelets; quenching ROS using excessive reducing agents: 20 μM GSH and 0.5 mM L-Cysteine, did not block the inhibitory effects. The NADPH oxidase inhibitor Apocynin also had no effect.PL inhibited collagen-induced platelet reactivity by targeting the JAK2-STAT3 pathway. We also provide experimental evidence that PL and collagen induce different oxidants that have differential effects on platelets. Studying these differential effects may uncover new mechanisms of regulating platelet functions by oxidants in redox signals.

  12. Hes1 promotes the IL-22-mediated antimicrobial response by enhancing STAT3-dependent transcription in human intestinal epithelial cells

    International Nuclear Information System (INIS)

    Highlights: •Hes1 enhances IL-22-STAT3 signaling in human intestinal epithelial cells. •Hes1 enhances REG family gene induction by IL-22-STAT3 signaling. •Protein level of Hes1 restricts the response to IL-22. •Present regulation of a cytokine signal represents a new mode of Hes1 function. -- Abstract: Notch signaling plays an essential role in the proliferation and differentiation of intestinal epithelial cells (IECs). We have previously shown that Notch signaling is up-regulated in the inflamed mucosa of ulcerative colitis (UC) and thereby plays an indispensable role in tissue regeneration. Here we show that in addition to Notch signaling, STAT3 signaling is highly activated in the inflamed mucosa of UC. Forced expression of the Notch target gene Hes1 dramatically enhanced the IL-22-mediated STAT3-dependent transcription in human IECs. This enhancement of STAT3-dependent transcription was achieved by the extended phosphorylation of STAT3 by Hes1. Microarray analysis revealed that Hes1-mediated enhancement of IL-22-STAT3 signaling significantly increased the induction of genes encoding antimicrobial peptides, such as REG1A, REG3A and REG3G, in human IECs. Conversely, the reduction of Hes1 protein levels with a γ-secretase inhibitor significantly down-regulated the induction of those genes in IECs, resulting in a markedly poor response to IL-22. Our present findings identify a new role for the molecular function of Hes1 in which the protein can interact with cytokine signals and regulate the immune response of IECs

  13. Hes1 promotes the IL-22-mediated antimicrobial response by enhancing STAT3-dependent transcription in human intestinal epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Murano, Tatsuro [Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Okamoto, Ryuichi, E-mail: rokamoto.gast@tmd.ac.jp [Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Department of Advanced GI Therapeutics, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Ito, Go; Nakata, Toru; Hibiya, Shuji; Shimizu, Hiromichi; Fujii, Satoru; Kano, Yoshihito; Mizutani, Tomohiro; Yui, Shiro; Akiyama-Morio, Junko; Nemoto, Yasuhiro [Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Tsuchiya, Kiichiro; Nakamura, Tetsuya [Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Department of Advanced GI Therapeutics, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan); Watanabe, Mamoru [Department of Gastroenterology and Hepatology, Graduate School, Tokyo Medical and Dental University, Tokyo (Japan)

    2014-01-17

    Highlights: •Hes1 enhances IL-22-STAT3 signaling in human intestinal epithelial cells. •Hes1 enhances REG family gene induction by IL-22-STAT3 signaling. •Protein level of Hes1 restricts the response to IL-22. •Present regulation of a cytokine signal represents a new mode of Hes1 function. -- Abstract: Notch signaling plays an essential role in the proliferation and differentiation of intestinal epithelial cells (IECs). We have previously shown that Notch signaling is up-regulated in the inflamed mucosa of ulcerative colitis (UC) and thereby plays an indispensable role in tissue regeneration. Here we show that in addition to Notch signaling, STAT3 signaling is highly activated in the inflamed mucosa of UC. Forced expression of the Notch target gene Hes1 dramatically enhanced the IL-22-mediated STAT3-dependent transcription in human IECs. This enhancement of STAT3-dependent transcription was achieved by the extended phosphorylation of STAT3 by Hes1. Microarray analysis revealed that Hes1-mediated enhancement of IL-22-STAT3 signaling significantly increased the induction of genes encoding antimicrobial peptides, such as REG1A, REG3A and REG3G, in human IECs. Conversely, the reduction of Hes1 protein levels with a γ-secretase inhibitor significantly down-regulated the induction of those genes in IECs, resulting in a markedly poor response to IL-22. Our present findings identify a new role for the molecular function of Hes1 in which the protein can interact with cytokine signals and regulate the immune response of IECs.

  14. STAT3 is a key transcriptional regulator of cancer stem cell marker CD133 in HCC

    Science.gov (United States)

    Ghoshal, Sarani; Fuchs, Bryan C.

    2016-01-01

    Cancer stem cell (CSC) marker CD133 was found to be upregulated in many cancers including hepatocellular carcinoma (HCC). However, the molecular mechanism of CD133 regulation in the liver tumor microenvironment has remained elusive. In this study Won and colleagues report that interleukin-6 (IL-6) mediated signal transducer and activator of transcription factor 3 (STAT3) signaling and hypoxia enhance the expression of CD133 and promote the progression of HCC. PMID:27275460

  15. STAT3 as a chemoprevention target in carcinogen-induced head and neck squamous cell carcinoma.

    OpenAIRE

    Peyser, ND; Wang, L.; Zeng, Y.; Acquafondata, M.; Freilino, ML; Li, H.; M. Sen; Gooding, WE; Satake, M; Wang, Z.; Johnson; Grandis, JR

    2016-01-01

    Head and neck squamous cell carcinoma (HNSCC) is a frequently fatal disease due in large part to a high rate of second primary tumor (SPT) formation. The 4-nitroquinoline 1-oxide (4-NQO) mouse model of oral carcinogenesis provides a robust system in which to study chemopreventive agents in the context of chemically-induced HNSCC tumors. Signal transducer and activator of transcription 3 (STAT3) is a potent oncogene that is hyperactivated by tyrosine phosphorylation early in HNSCC carcinogenes...

  16. Cyclosporine A sensitizes human non-small cell lung cancer cells to gefitinib through inhibition of STAT3.

    Science.gov (United States)

    Shou, Jiawei; You, Liangkun; Yao, Junlin; Xie, Jiansheng; Jing, Jing; Jing, Zhao; Jiang, Liming; Sui, Xinbing; Pan, Hongming; Han, Weidong

    2016-08-28

    The epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) have dramatically prolonged the overall survival of non-small cell lung cancer (NSCLC) patients with EGFR-activating mutation, but the presence of primary or acquired resistance eventually leads to therapeutic failure. Thus, how to improve the efficacy and reverse the resistance to EGFR-TKIs remains a significant challenge. In this study, we found that CsA significantly augmented the anti-cancer effect of gefitinib in EGFR-TKI-sensitive and -resistant NSCLC cells. Mechanistically, CsA promoted gefitinib-induced apoptosis through inhibition of the STAT3 pathway. Similar with the function of CsA, siRNAs against STAT3 also enhanced gefitinib-induced apoptosis in multiple lung cancer cells. Xenograft studies further demonstrated that CsA promoted the anti-cancer activity of gefitinib on lung cancer cells through inhibition of STAT3. Moreover, NSCLC patients with high levels of phosphorylated STAT3 (Y705) showed a significantly poorer therapeutic response to EGFR-TKIs. This study provides preclinical evidence that the combination of CsA or a STAT3 inhibitor with EGFR-TKIs is a promising approach to improve the efficacy of EGFR-TKIs for the treatment of patients with advanced NSCLC. PMID:27264264

  17. Dynamic Balance of pSTAT1 and pSTAT3 in C57BL/6 Mice Infected with Lethal or Nonlethal Plasmodium yoelii

    Institute of Scientific and Technical Information of China (English)

    Xibao Shi; Li Qin; Guangjie Liu; Siting Zhao; Nanzheng Peng; Xiaoping Chen

    2008-01-01

    Signal transducer and activator of transcription(STAT)proteins play an important role in cytokine signaling pathways and regulation of immune responses.The balance of the phosphorylated(activated)STAT1(pSTAT1) and STAT3 (pSTAT3)has been documented in cancer immunology.In this study,we investigated the dynamic balance of pSTAT1 and pSTAT3 in C57BL/6 mice infected with either a nonlethal(py17XNL)or lethal(ey17XL) strain of Plasmodium yoelii.Both pylNL and ey17XL infections induced a maximum activation of STAT1 and STAT3 On the first day after parasite inoculation.Additionally,the py17XNL infection induced a pSTAT1- dominant response in mice during the early stage of infection,with the resolution of parasitemia.In contrast, Py17XL infection induced a pSTAT3-dominant response during the early phase of infection,with the death of the animals.Our results indicated that maximum activation of STAT1 and STAT3 occurred much earlier than the peak levels of cytokines induced by Plasmodium yoelii infection based on previous reports and that infection with Py17XNL-and py17XL induced different dynamic patterns of pSTAT1 and pSTAT3 balance.

  18. MPT0B098, a Microtubule Inhibitor, Suppresses JAK2/STAT3 Signaling Pathway through Modulation of SOCS3 Stability in Oral Squamous Cell Carcinoma.

    Science.gov (United States)

    Peng, Hsuan-Yu; Cheng, Yun-Ching; Hsu, Yuan-Ming; Wu, Guan-Hsun; Kuo, Ching-Chuan; Liou, Jing-Ping; Chang, Jang-Yang; Jin, Shiow-Lian Catherine; Shiah, Shine-Gwo

    2016-01-01

    Microtubule inhibitors have been shown to inhibit Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) signal transduction pathway in various cancer cells. However, little is known of the mechanism by which the microtubule inhibitors inhibit STAT3 activity. In the present study, we examined the effect of a novel small-molecule microtubule inhibitor, MPT0B098, on STAT3 signaling in oral squamous cell carcinoma (OSCC). Treatment of various OSCC cells with MPT0B098 induced growth inhibition, cell cycle arrest and apoptosis, as well as increased the protein level of SOCS3. The accumulation of SOCS3 protein enhanced its binding to JAK2 and TYK2 which facilitated the ubiquitination and degradation of JAK2 and TYK2, resulting in a loss of STAT3 activity. The inhibition of STAT3 activity led to sensitization of OSCC cells to MPT0B098 cytotoxicity, indicating that STAT3 is a key mediator of drug resistance in oral carcinogenesis. Moreover, the combination of MPT0B098 with the clinical drug cisplatin or 5-FU significantly augmented growth inhibition and apoptosis in OSCC cells. Taken together, our results provide a novel mechanism for the action of MPT0B098 in which the JAK2/STAT3 signaling pathway is suppressed through the modulation of SOCS3 protein level. The findings also provide a promising combinational therapy of MPT0B098 for OSCC. PMID:27367272

  19. MPT0B098, a Microtubule Inhibitor, Suppresses JAK2/STAT3 Signaling Pathway through Modulation of SOCS3 Stability in Oral Squamous Cell Carcinoma.

    Directory of Open Access Journals (Sweden)

    Hsuan-Yu Peng

    Full Text Available Microtubule inhibitors have been shown to inhibit Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3 signal transduction pathway in various cancer cells. However, little is known of the mechanism by which the microtubule inhibitors inhibit STAT3 activity. In the present study, we examined the effect of a novel small-molecule microtubule inhibitor, MPT0B098, on STAT3 signaling in oral squamous cell carcinoma (OSCC. Treatment of various OSCC cells with MPT0B098 induced growth inhibition, cell cycle arrest and apoptosis, as well as increased the protein level of SOCS3. The accumulation of SOCS3 protein enhanced its binding to JAK2 and TYK2 which facilitated the ubiquitination and degradation of JAK2 and TYK2, resulting in a loss of STAT3 activity. The inhibition of STAT3 activity led to sensitization of OSCC cells to MPT0B098 cytotoxicity, indicating that STAT3 is a key mediator of drug resistance in oral carcinogenesis. Moreover, the combination of MPT0B098 with the clinical drug cisplatin or 5-FU significantly augmented growth inhibition and apoptosis in OSCC cells. Taken together, our results provide a novel mechanism for the action of MPT0B098 in which the JAK2/STAT3 signaling pathway is suppressed through the modulation of SOCS3 protein level. The findings also provide a promising combinational therapy of MPT0B098 for OSCC.

  20. Different associations of CD45 isoforms with STAT3, PKC and ERK regulate IL-6-induced proliferation in myeloma.

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    Xu Zheng

    Full Text Available In response to interleukin 6 (IL-6 stimulation, both CD45RO and CD45RB, but not CD45RA, translocate to lipid rafts. However, the significance of this distinct translocation and the downstream signals in CD45 isoforms-participated IL-6 signal are not well understood. Using sucrose fractionation, we found that phosphorylated signal transducer and activator of transcription (STAT3 and STAT1 were mainly localized in lipid rafts in response to IL-6 stimulation, despite both STAT3 and STAT1 localizing in raft and non-raft fractions in the presence or absence of IL-6. On the other hand, extracellular signal-regulated kinase (ERK, and phosphorylated ERK were localized in non-raft fractions regardless of the existence of IL-6. The rafts inhibitor significantly impeded the phosphorylation of STAT3 and STAT1 and nuclear translocation, but had little effect on (and only postponing the phosphorylation of ERK. This data suggests that lipid raft-dependent STAT3 and STAT1 pathways are dominant pathways of IL-6 signal in myeloma cells. Interestingly, the phosphorylation level of STAT3 but not STAT1 in CD45+ cells was significantly higher compared to that of CD45- cells, while the phosphorylation level of ERK in CD45+ myeloma cells was relatively low. Furthermore, exogenously expressed CD45RO/RB significantly enhanced STAT3, protein kinase C (PKC and downstream NF-κB activation; however, CD45RA/RB inhibited IL-6-induced ERK phosphorylation. CD45 also enhanced the nuclear localization of STAT3 but not that of STAT1. In response to IL-6 stimulation, CD45RO moved into raft compartments and formed a complex with STAT3 and PKC in raft fraction, while CD45RA remained outside of lipid rafts and formed a complex with ERK in non-raft fraction. This data suggests a different role of CD45 isoforms in IL-6-induced signaling, indicating that while CD45RA/RB seems inhibit the rafts-unrelated ERK pathway, CD45RO/RB may actually work to enhance the rafts-related STAT3 and PKC

  1. STAT3 or USF2 contributes to HIF target gene specificity.

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    Matthew R Pawlus

    Full Text Available The HIF1- and HIF2-mediated transcriptional responses play critical roles in solid tumor progression. Despite significant similarities, including their binding to promoters of both HIF1 and HIF2 target genes, HIF1 and HIF2 proteins activate unique subsets of target genes under hypoxia. The mechanism for HIF target gene specificity has remained unclear. Using siRNA or inhibitor, we previously reported that STAT3 or USF2 is specifically required for activation of endogenous HIF1 or HIF2 target genes. In this study, using reporter gene assays and chromatin immuno-precipitation, we find that STAT3 or USF2 exhibits specific binding to the promoters of HIF1 or HIF2 target genes respectively even when over-expressed. Functionally, HIF1α interacts with STAT3 to activate HIF1 target gene promoters in a HIF1α HLH/PAS and N-TAD dependent manner while HIF2α interacts with USF2 to activate HIF2 target gene promoters in a HIF2α N-TAD dependent manner. Physically, HIF1α HLH and PAS domains are required for its interaction with STAT3 while both N- and C-TADs of HIF2α are involved in physical interaction with USF2. Importantly, addition of functional USF2 binding sites into a HIF1 target gene promoter increases the basal activity of the promoter as well as its response to HIF2+USF2 activation while replacing HIF binding site with HBS from a HIF2 target gene does not change the specificity of the reporter gene. Importantly, RNA Pol II on HIF1 or HIF2 target genes is primarily associated with HIF1α or HIF2α in a STAT3 or USF2 dependent manner. Thus, we demonstrate here for the first time that HIF target gene specificity is achieved by HIF transcription partners that are required for HIF target gene activation, exhibit specific binding to the promoters of HIF1 or HIF2 target genes and selectively interact with HIF1α or HIF2α protein.

  2. Oncogenic Ras-Induced Morphologic Change Is through MEK/ERK Signaling Pathway to Downregulate Stat3 at a Posttranslational Level in NIH3T3 Cells

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    Hsuan-Heng Yeh

    2008-01-01

    Full Text Available Ras is a key regulator of the MAP kinase-signaling cascade and may cause morphologic change of Ras-transformed cells. Signal transducer and activator of transcription 3 (Stat3 can be activated by cytokine stimulation. In this study, we unravel that Ha-rasV12 overexpression can downregulate the expression of Stat3 protein at a posttranslational level in NIH3T3 cells. Furthermore, we demonstrate that Stat3 expression downregulated by Ha-rasV12 overexpression is through proteosome degradation and not through a mTOR/p70S6K-related signaling pathway. The suppression of Stat3 accompanied by the morphologic change induced by Ha-rasV12 was through mitogen extracellular kinase (MEK/extracellular-regulated kinase (ERK signaling pathway. Microtubule disruption is involved in Ha-rasV12-induced morphologic change, which could be reversed by overexpression of Stat3. Taken together, we are the first to demonstrate that Stat3 protein plays a critical role in Ha-rasV12-induced morphologic change. Oncogenic Ras-triggered morphologic change is through the activation of MEK/ERK to posttranslationally downregulate Stat3 expression. Our finding may shed light on developing novel therapeutic strategies against Ras-related tumorigenesis.

  3. Screening of invasion and metastasis related genes regulated by Stat3 in pancreatic cancer SW1990 cell%STAT3调控胰腺癌侵袭转移相关基因的筛选

    Institute of Scientific and Technical Information of China (English)

    李海东; 裘正军; 黄陈; 江弢; 曹俊

    2012-01-01

    Objective To screen the genes related with signal transducers and activators of transcription 3 (STAT3) regulating pancreatic cancer invasion and metastasis by gene chips. Methods Human pancreatic cancer cell line SW1990 stably expressing low level of Stat3 was established by lentivirus transfection,while cells transfected with mock plasmid and cells without transfection served as control groups.The differences of invasion and metastasis related genes expression among the three groups were screened by gene chips.STAT3 mRNA and protein expression was measured by real-time PCR and Western blot.Three differentially expressed genes (MMP-7,IL-1β and IgTα7) were verified.Results The expression level of STAT3 mRNA was 0.391 ± 0.037 after pancreatic cancer SW1990 cell trarsfected with STAT3 targeted lentivirus,which was significantly lower than those in mock plasmid group (1.002 ± 0.015) and nontransfected group ( 1.206 ± 0.042,P < 0.05 ) ; the expression level of STAT3 protein was 182.38 ± 65.32,which was significantly lower than those in mock plasmid group (223.40 ±58.40) and non-transfected group (212.33 ±53.69).Eight invasion and metastasis related genes of SW1990 lowly expressing Stat3 were upregulated,while 3 genes were down-regulated.By verification,the mRNA level of MMP-7 and IL-1β were lower than in control group transfected with mook plassmid(0.287 ± 0.115 vs 1.010 ± 0.124,t =19.45,P =0.000;0.490 ± 0.10 vs 1.002 ± 0.002,t =13.83,P =0.000),but the mRNA level of IgTα7 was not decreased (1.173 ±0.280 vs 0.998 ±0.003,t =4.236,P =0.094).Meanwhile,the protein level of MMP-7 was significantly down-regulated when Stat3 was knocked down.Conclusions Stat3 causes changes of expressions of many invasion and metastasis-related genes of SW1990,and MMP-7 may be the main target gene regulated by Stat3.%目的 应用基因芯片筛选信号转导与转录激活因子3(STAT3)调控胰腺癌侵袭转移的相关基因.方法 以慢病毒感染获得稳定STAT3

  4. The Role of p-STAT3 as a Prognostic and Clinicopathological Marker in Colorectal Cancer: A Systematic Review and Meta-Analysis

    Science.gov (United States)

    Chu, Qi; Gan, Yong; Ren, Hui; Zhang, Liyan; Wang, Liwei; Li, Xiaoxiu; Wang, Wei

    2016-01-01

    Objective High expression of phosphorylated signal transducer and activator of transcription 3 (p-STAT3) has been detected in a variety of human tumors. However, the association of positive p-STAT3 expression with clinicopathological parameters and the prognosis of colorectal cancer patients remain controversial. To identify the relationship between p-STAT3 expression and clinicopathological parameters and prognosis in patients with colorectal cancer, a systematic review and meta-analysis were performed. Methods We performed a comprehensive literature search from PubMed, EMBASE, and SinoMed through 27 March, 2016. Hazard ratios (HRs) with 95% confidence intervals (CI) were combined to evaluate the association between p-STAT3 expression and overall survival of colorectal cancer patients. Odds ratios (ORs) with 95% CI were combined to evaluate the association between p-STAT3 expression and clinicopathological parameters in patients with colorectal cancer. Results Seventeen studies including a total of 2,346 colorectal cancer patients were included in this meta-analysis. The combined HR was 1.43 (95% CI: 1.23–1.67, P < 0.001), which suggested a positive relationship between p-STAT3 overexpression and poorer overall survival of colorectal cancer patients. In addition, the results indicated that positive p-STAT3 expression was significantly associated with the presence of lymph node metastasis (OR: 2.43, 95% CI: 1.18–5.01, P = 0.02) but was not associated with TNM stage, tumor differentiation or gender. Conclusion The meta-analysis results suggest that p-STAT3 overexpression is unfavorable for the prognosis of colorectal cancer patients, and p-STAT3 overexpression is associated with the presence of lymph node metastasis among colorectal cancer patients. PMID:27504822

  5. Hedyotis diffusa Willd. extract suppresses proliferation and induces apoptosis via IL-6-inducible STAT3 pathway inactivation in human colorectal cancer cells

    OpenAIRE

    LIN, JIUMAO; LI, QIONGYU; Chen, Hongwei; Lin, Hui; LAI, ZIJUN; Peng, Jun

    2015-01-01

    Recent studies have indicated that the inflammatory microenvironment plays a significant role in colorectal cancer (CRC). The interleukin-6/signal transducer and activator of transcription 3 (IL-6/STAT3) signaling pathway mediates the proliferative and anti-apoptotic activities required for oncogenesis under inflammatory conditions; thus, suppressing tumor growth by targeting the IL-6/STAT3 pathway is a promising therapeutic strategy for CRC. Our previous study reported that the ethanol extra...

  6. Connective tissue growth factor reacts as an IL-6/STAT3-regulated hepatic negative acute phase protein

    Institute of Scientific and Technical Information of China (English)

    Olav A Gressner; Ieva Peredniene; Axel M Gressner

    2011-01-01

    AIM: To investigate the mechanisms involved in a possible modulator role of interleukin (IL)-6 signalling on CYR61-CTGF-NOV (CCN) 2/connective tissue growth factor (CTGF) expression in hepatocytes (PC) and to look for a relation between serum concentrations of these two parameters in patients with acute inflammation.METHODS: Expression of CCN2/CTGF, p-STAT3, p-Smad 3/1 and p-Smad2 was examined in primary freshly isolated rat or cryo-preserved human PC exposed to various stimuli by Western blotting, electrophoretic mobility shift assay (EMSA), reporter-gene-assays and reversetranscriptase polymerase chain reaction.RESULTS: IL-6 strongly down-regulated CCN2/CTGF protein and mRNA expression in PC, enhanceable by extracellular presence of the soluble IL-6 receptor gp80,and supported by an inverse relation between IL-6 and CCN2/CTGF concentrations in patients' sera. The inhibition of TGFβ1 driven CCN2/CTGF expression by IL-6 did not involve a modulation of Smad2 (and Smad1/3)signalling. However, the STAT3 SH2 domain binding peptide, a selective inhibitor of STAT3 DNA binding activity, counteracted the inhibitory effect of IL-6 on CCN2/CTGF expression much more pronounced than pyrrolidine-dithiocarbamate, an inhibitor primarily of STAT3 phosphorylation. An EMSA confirmed STAT3 binding to the proposed proximal STAT binding site in the CCN2 /CTGF promoter.CONCLUSION: CCN2/CTGF is identified as a hepatocellular negative acute phase protein which is downregulated by IL-6 via the STAT3 pathway through interaction on the DNA binding level.

  7. Cryptotanshinone suppresses the proliferation and induces the apoptosis of pancreatic cancer cells via the STAT3 signaling pathway.

    Science.gov (United States)

    Ge, Yuqing; Yang, Bo; Chen, Zhe; Cheng, Rubin

    2015-11-01

    Pancreatic cancer remains a challenging disease worldwide. Cryptotanshinone (CPT) is one of the active constituents of Salvia miltiorrhiza Bunge and exhibits significant antitumor activities in several human cancer cells. However, the efficacy and molecular mechanism of CPT in pancreatic cancer remains to be elucidated. In the present study, the effect of CPT on the proliferation, apoptosis and cell cycle of human pancreatic cancer cell BxPC‑3 cells was evaluated. The results demonstrated that CPT inhibited proliferation of the BxPC‑3 cells in a concentration‑dependent manner, and significantly induced cell apoptosis and cell cycle arrest. The protein levels of cleaved caspase‑3, caspase‑9 and poly ADP ribose polymerase were upregulated, while the levels of c‑myc, survivin and cyclin D1 were downregulated following treatment with CPT. In addition, CPT decreased the activities of signal transducer and activator of transcription 3 (STAT3) and several upstream regulatory signaling pathways after 24 h. However, CPT only inhibited the phosphorylation of STAT3 Tyr705 within 30 min, without marked effects on the phosphorylation of the other proteins. These results suggested that the inhibition of STAT3 activity by CPT was directly and independent of the upstream regulators in human pancreatic cancer. The present study demonstrated that CPT exerts anticancer effects by inducing apoptosis and cell cycle arrest via inhibition of the STAT3 signaling pathway in human BxPC-3 cells.

  8. Euglycemia restoration by central leptin in type 1 diabetes requires STAT3 signaling but not fast-acting neurotransmitter release

    Science.gov (United States)

    Central leptin action is sufficient to restore euglycemia in insulinopenic type 1 diabetes (T1D); however, the underlying mechanism remains poorly understood. To examine the role of intracellular signal transducer and activator of transcription 3 (STAT3) pathways, we used LepRs/s mice with disrupted...

  9. STAT3 and the Hyper-IgE syndrome

    DEFF Research Database (Denmark)

    Mogensen, Trine H

    2013-01-01

    During recent years a number of primary immunodeficiencies resulting from impaired function of JAK-STAT molecules have been described. One of these is the Hyper-IgE syndrome (HIES) characterized by elevated IgE levels, eczema, recurrent staphylococcal skin and pulmonary infections and pleiotropic...... multiple cytokine and growth factor receptors and thus regulates antimicrobial responses and cell survival, impaired STAT3 function results in immunodeficiency and in some cases tumorigenesis. However, as the immunological and molecular basis of HIES is being unraveled, important biological and...

  10. Crispene E, a cis-clerodane diterpene inhibits STAT3 dimerization in breast cancer cells.

    Science.gov (United States)

    Mantaj, Julia; Rahman, S M Abdur; Bokshi, Bishwajit; Hasan, Choudhury M; Jackson, Paul J M; Parsons, Richard B; Rahman, Khondaker M

    2015-04-01

    Crispene E, a new clerodane-type diterpene, inhibited STAT3 dimerization in a cell-free fluorescent polarisation assay and was found to have significant toxicity against STAT3-dependent MDA-MB 231 breast cancer cell line and selectively inhibited the expression of STAT3 and STAT3 target genes cyclin D1, Fascin and bcl-2. Molecular docking studies suggest the molecule inhibits STAT3 by interacting with its SH2 domain. The compound has been isolated from Tinospora crispa and characterized using standard spectroscopic techniques. PMID:25721973

  11. GRIM-19及其靶基因产物STAT3在人乳腺癌组织中的表达%Expression of GRIM-19 and its target gene product STAT3 in human breast cancer

    Institute of Scientific and Technical Information of China (English)

    任敏; 汪英; 刘骁蕾; 王本忠

    2013-01-01

    Objective To evaluate gene associated with retinoid-interferon-induced mortality-19 (GRIM-19) expression levels and the correlation with its target gene product signal transducers and activator of transcription 3 (STAT3)in human breast cancer tissues and normal gland tissues,and to analyze their roles in the tumorigenesis of breast cancer.Methods The expression of GRIM-19 and STAT3 protein and mRNA in 40 cases of breast cancer tissues and 40 cases of normal gland tissues was detected by immunohistochemistry and Western blot.The correlation of the expression of GRIM-19 and STAT3 to various clinicopathologic characteristics of breast cancer were analyzed statistically.The mRNA expression and gene mutation of GRIM-19 in breast cancer cell line MCF-7 and 25 specimens of breast cancer and normal gland tissue were detected by reverse transcription-polymerase chain reaction(RT-PCR)and sequencing.Results The protein and mRNA expression of GRIM-19 was obviously lower in breast cancer than in normal gland tissues (P < 0.05) while the protein and mRNA expression of STAT3 was obviously higher in breast cancer than in normal gland tissues(P <0.05).The expression of GRIM-19 and STAT3 was negatively correlated with each other(x2 =8.25,P <0.01).Breast cancer samples exhibited low level of GRIM-19 and moderate to high level of STAT3 expression.In contrast,the normal gland tissue was characterized by high level of GRIP-19 and low level of STAT3 expression.The protein expression of GRIM-19 was correlated with the histological grading and clinical stage of breast cancer(P < 0.05).STAT3 was not correlated with clinicopathologic characteristics of breast cancer (P > 0.05).No mutation of GRIM-19 gene was detected in breast cancer tissues,normal gland tissues or MCF-7 breastcancer cells.Conclusions The low expression of GRIM-19 and the high expression of STAT3 co-exist in breast cancer.Downregulation of GRIM-19 was closely correlated with increased histological grade

  12. Sphingosylphosphorylcholine promotes the differentiation of resident Sca-1 positive cardiac stem cells to cardiomyocytes through lipid raft/JNK/STAT3 and β-catenin signaling pathways.

    Science.gov (United States)

    Li, Wenjing; Liu, Honghong; Liu, Pingping; Yin, Deling; Zhang, Shangli; Zhao, Jing

    2016-07-01

    Resident cardiac Sca-1-positive (+) stem cells may differentiate into cardiomyocytes to improve the function of damaged hearts. However, little is known about the inducers and molecular mechanisms underlying the myogenic conversion of Sca-1(+) stem cells. Here we report that sphingosylphosphorylcholine (SPC), a naturally occurring bioactive lipid, induces the myogenic conversion of Sca-1(+) stem cells, as evidenced by the increased expression of cardiac transcription factors (Nkx2.5 and GATA4), structural proteins (cardiac Troponin T), transcriptional enhancer (Mef2c) and GATA4 nucleus translocation. First, SPC activated JNK and STAT3, and the JNK inhibitor SP600125 or STAT3 inhibitor stattic impaired the SPC-induced expression of cardiac transcription factors and GATA4 nucleus translocation, which suggests that JNK and STAT3 participated in SPC-promoted cardiac differentiation. Moreover, STAT3 activation was inhibited by SP600125, whereas JNK was inhibited by β-cyclodextrin as a lipid raft breaker, which indicates a lipid raft/JNK/STAT3 pathway involved in SPC-induced myogenic transition. β-Catenin, degraded by activated GSK3β, was inhibited by SPC. Furthermore, GSK3β inhibitors weakened but the β-catenin inhibitor promoted SPC-induced differentiation. We found no crosstalk between the lipid raft/JNK/STAT3 and β-catenin pathway. Our study describes a lipid, SPC, as an endogenic inducer of myogenic conversion in Sca-1(+) stem cells with low toxicity and high efficiency for uptake.

  13. EGCG attenuates autoimmune arthritis by inhibition of STAT3 and HIF-1α with Th17/Treg control.

    Directory of Open Access Journals (Sweden)

    Eun-Ji Yang

    Full Text Available Epigallocatechin-3-gallate (EGCG is a green tea polyphenol exerting potent anti-oxidant and anti-inflammatory effects by inhibiting signaling and gene expression. The objective of the study was to evaluate the effect of EGCG on interleukin (IL-1 receptor antagonist knockout (IL-1RaKO autoimmune arthritis models. IL-1RaKO arthritis models were injected intraperitoneally with EGCG three times per week after the first immunization. EGCG decreased the arthritis index and showed protective effects against joint destruction in the IL-1RaKO arthritis models. The expression of pro-inflammatory cytokines, oxidative stress proteins, and p-STAT3 (Y705 and p-STAT3 (S727, mTOR and HIF-1α were significantly lower in mice treated with EGCG. EGCG reduced osteoclast markers in vivo and in vitro along with anti-osteoclastic activity was observed in EGCG-treated IL-1RaKO mice. The proportion of Foxp3(+ Treg cells increased in the spleens of mice treated with EGCG, whereas the proportion of Th17 cells reduced. In vitro, p-STAT3 (Y705 and p-STAT3 (S727, HIF1α and glycolytic pathway molecules were decreased by EGCG. EGCG suppressed the activation of mTOR and subsequently HIF-1α, which is considered as a metabolic check point of Th17/Treg differentiation supporting the therapeutic potential of EGCG in autoimmune arthritis.

  14. CCR5 Blockade Suppresses Melanoma Development Through Inhibition of IL-6-Stat3 Pathway via Upregulation of SOCS3.

    Science.gov (United States)

    Tang, Qiu; Jiang, Jun; Liu, Jian

    2015-12-01

    In order to understand how tumor cells can escape immune surveillance mechanisms and thus develop antitumor therapies, it is critically important to investigate the mechanisms by which the immune system interacts with the tumor microenvironment. In our current study, we found that chemokine receptor 5 (CCR5) neutralization resulted in reduced melanoma tumor size, decreased percentage of CD11b+ Gr-1(+) myeloid-derived suppressor cells (MDSCs), and increased proportion of cluster of differentiation (CD)3+ T cells in tumor tissues. Suppressive activity of MDSCs on CD4+ T cells and CD8+ T cell proliferation is significantly inhibited by anti-CCR5 antibody. CCR5 blockade also suppresses interleukin (IL)-6 induction, which in turn deactivates signal transducer and activator of transcription 3 (Stat3) in tumors. Furthermore, the suppressed B16 tumor growth induced by CCR5 blockade is abolished with additional administration of recombinant IL-6. CCR5 blockade also induces suppressor of cytokine signaling 3 (SOCS3) upregulations, and anti-CCR5 antibody fails to suppress expression of phospho-Stat3 (p-Stat3), matrix metallopeptidase 9 (MMP9), and IL-6 in cells transfected with SOCS3 short-interfering RNA (SiRNA). All these data suggest that CCR5 blockade suppresses melanoma development through inhibition of IL-6-Stat3 pathway via upregulation of SOCS3.

  15. Arctigenin promotes apoptosis in ovarian cancer cells via the iNOS/NO/STAT3/survivin signalling.

    Science.gov (United States)

    Huang, Ke; Li, Li-an; Meng, Yuan-guang; You, Yan-qin; Fu, Xiao-yu; Song, Lei

    2014-12-01

    Arctigenin is a biologically active lignan extracted from the seeds of Arctium lappa and shows anticancer activity against a variety of human cancers. The aim of this study was to determine the effects of arctigenin on ovarian cancer cell proliferation and survival and associated molecular mechanisms. Human ovarian cancer OVCAR3 and SKOV3 cells were treated with arctigenin, and cell proliferation and apoptosis were assessed. Western blot analysis was used to examine signal transducer and activator of transcription-3 (STAT3) phosphorylation and survivin and inducible nitric oxide synthase (iNOS) expression. The involvement of STAT3/survivin/iNOS/NO signalling in arctigenin action was checked. Arctigenin treatment resulted in a significant and dose-dependent inhibition of cell proliferation. Arctigenin-treated cells showed a 4-6 times increase in the percentage of apoptosis, compared with control cells. Pre-treatment with Ac-DEVD-CHO, a specific inhibitor of caspase-3, counteracted the induction of apoptosis by arctigenin. Arctigenin treatment significantly inhibited STAT3 phosphorylation and survivin and iNOS expression. Arctigenin-induced apoptosis was impaired by pre-transfection with survivin-expressing plasmid or addition of chemical nitric oxide (NO) donors. Additionally, exogenous NO prevented the suppression of STAT3 phosphorylation and survivin expression by arctigenin. Arctigenin treatment inhibits the proliferation and induces caspase-3-dependent apoptosis of ovarian cancer cells. Suppression of iNOS/NO/STAT3/survivin signalling is causally linked to the anticancer activity of arctigenin. Therefore, arctigenin may be applicable to anticancer therapy for ovarian cancer. PMID:24842412

  16. Study of STAT3 G-quadruplex folding patterns by CD spectroscopy and molecular modeling

    Institute of Scientific and Technical Information of China (English)

    Sen Lin; Ming Xu; Gu Yuan

    2012-01-01

    The G-quadruplexes formed from G-rich strands in the telomere and oncogene-promoter regions are regarded as new promising targets in the cancer therapy.A G-quadruplex in the downstream flanking region of the signal transducer and activator of transcription 3 (STAT3) gene was explored.Its folding patterns were proposed to be 3∶2∶2 and 3∶3∶1 loop isomers by the mutation analysis by CD spectroscopy.The structures were constructed and refined by molecular modeling method.

  17. Stat3 promotes invasion of esophageal squamous cell carcinoma through up-regulation of MMP2.

    Science.gov (United States)

    Xuan, Xaioyan; Li, Shanshan; Lou, Xi; Zheng, Xianzhao; Li, Yunyun; Wang, Feng; Gao, Yuan; Zhang, Hongyan; He, Hongliu; Zeng, Qingru

    2015-05-01

    Stat3 alters the expression of its downstream genes and is associated with tumor invasion and metastasis in several human cancers. Its role in esophageal squamous cell carcinoma (ESCC) has not been well characterized. We examined the tumor sections of 100 cases of ESCC by immunohistochemistry and observed significant overexpression of Stat3 in the cytoplasm of 89% of ESCC cells and of phosphorylated Stat3 (p-Stat3) in the nuclei of 71% of ESCC when compare with normal esophageal mucosa (72%, p = 0.02; and 31%, p = 0.001). Overexpression of Stat3 and p-Stat3 positively correlated with that of matrix metalloproteinase-2 (MMP2), a known regulator for cell migration, in 65% of ESCC while only 26% shown in benign esophageal mucosa. To further investigate the association of Stat3 with tumor metastasis in vitro, invasion of EC-1 cells (a human ESCC cell line) were investigated with Boyden chambers. The results showed that transfection of Stat3 not only promoted invasion of EC-1 cells but also significantly induced MMP2 expression in a dose-dependent manner. In contrast, suppressing expression of endogenous Stat3 mRNA and protein by Stat3 siRNA significantly reduced EC-1 cell invasion and MMP2 expression. A high-affinity Stat3-binding element was localized to the positions of 648-641 bp (TTCTCGAA) in the MMP2 promoter with electrophoretic mobility shift assay. Our results suggest that Stat3, p-Stat3, and MMP2 were overexpressed in ESCC and associated with invasion of ESCC; and Stat3 up-regulated expression of MMP2 in ESCC through directly binding to the MMP2 promoter.

  18. Th22 cells control colon tumorigenesis through STAT3 and Polycomb Repression complex 2 signaling.

    Science.gov (United States)

    Sun, Danfeng; Lin, Yanwei; Hong, Jie; Chen, Haoyan; Nagarsheth, Nisha; Peng, Dongjun; Wei, Shuang; Huang, Emina; Fang, Jingyuan; Kryczek, Ilona; Zou, Weiping

    2016-08-01

    Th22 cells traffic to and retain in the colon cancer microenvironment, and target core stem cell genes and promote colon cancer stemness via STAT3 and H3K79me2 signaling pathway and contribute to colon carcinogenesis. However, whether Th22 cells affect colon cancer cell proliferation and apoptosis remains unknown. We studied the interaction between Th22 cells and colon cancer cells in the colon cancer microenvironment. Colon cancer proliferation was examined by flow cytometry analysis and H(3) thymidine incorporation. Cell cycle related genes were quantified by real-time PCR and Western blotting. We transfected colon cancer cells with lentiviral vector encoding specific gene shRNAs and used chromatin immunoprecipitation (ChIP) assay to determine the genetic signaling involved in interleukin (IL)-22-mediated colon cancer cell proliferation. We showed that Th22 cells released IL-22 and stimulated colon cancer proliferation. Mechanistically, IL-22 activated STAT3, and subsequently STAT3 bound to the promoter areas of the Polycomb Repression complex 2 (PRC2) components SUZ12 and EED, and stimulated the expression of PRC2. Consequently, the activated PRC2 catalyzed the promoters of the cell cycle check-point genes p16 and p21, and inhibited their expression through H3K27me3-mediated histone methylation, and ultimately caused colon cancer cell proliferation. Bioinformatics analysis revealed that the levels of IL-22 expression positively correlated with the levels of genes controlling cancer proliferation and cell cycling in colon cancer. In addition to controlling colon cancer stemness, Th22 cells support colon carcinogenesis via affecting colon cancer cell proliferation through a distinct histone modification. PMID:27622053

  19. STAT3-silenced human dendritic cells have an enhanced ability to prime IFNγ production by both αβ and γδ T lymphocytes.

    Science.gov (United States)

    Sanseverino, Isabella; Purificato, Cristina; Varano, Barbara; Conti, Lucia; Gessani, Sandra; Gauzzi, M Cristina

    2014-07-01

    Dendritic cells (DC) are an attractive target for therapeutic manipulation of the immune system to enhance insufficient immune responses, such those occurring in cancer, or to dampen dangerous responses in allergic and autoimmune diseases. Main goal of this study was to manipulate human monocyte-derived DC (MDDC) function by silencing STAT3, since this transcription factor plays a key role as a negative regulator of immune surveillance, and is strongly involved in inflammation. STAT3 silencing did not affect the immunophenotype of both immature and toll-like receptor (TLR) ligand-matured DC. However, an altered cytokine secretion profile, characterized by lower IL10 and higher IL12 and TNFα levels, was observed in silenced DC with respect to control cells upon TLR triggering. Accordingly, STAT3 silenced MDDC promoted a higher IFNγ production by CD4(+) naïve T cells. Furthermore, STAT3 silencing in MDDC favored the activation of γδ T lymphocytes, an immune cell population with important antitumor effector activities. This effect was at least in part mediated by the increased IL12 production by silenced cells. STAT3 silencing also increased the levels of CCL4, a CCR5-binding chemokine known to be involved in T helper 1 (Th1) cell recruitment. Altogether these results strengthen the role of STAT3 as a critical check point of the suppression of Th1 responses, unraveling its potential to dampen DC capability to both induce and recruit different IFNγ producing T lymphocyte subsets. PMID:24674241

  20. The lipopolysaccharide-binding protein is a secretory class 1 acute-phase protein whose gene is transcriptionally activated by APRF/STAT/3 and other cytokine-inducible nuclear proteins.

    OpenAIRE

    Schumann, R.R.; Kirschning, C.J.; Unbehaun, A; Aberle, H P; Knope, H P; Lamping, N; Ulevitch, R J; Herrmann, F.

    1996-01-01

    Acute-phase reactants (APRs) are proteins synthesized in the liver following induction by interleukin-1 (IL-1), IL-6, and glucocorticoids, involving transcriptional gene activation. Lipopolysaccharide-binding protein (LBP) is a recently identified hepatic secretory protein potentially involved in the pathogenesis of sepsis, capable of binding the bacterial cell wall product endotoxin and directing it to its cellular receptor, CD14. In order to examine the transcriptional induction mechanisms ...

  1. Inhibition of Jak-STAT3 pathway enhances bufalin-induced apoptosis in colon cancer SW620 cells

    Directory of Open Access Journals (Sweden)

    Zhu Zhitu

    2012-10-01

    Full Text Available Abstract Background The purpose of the research is to investigate the roles of Jak-STAT3 signaling pathway in bufalin-induced apoptosis in colon cancer SW620 cells. Methods The inhibitory effects of bufalin on cell proliferation were determined by MTT (Methyl thiazolyltetrazolium assay. The morphological changes of cells were measured by Wright-Giemsa staining. The cell cycle arrest and apoptosis were tested by flow cytometry analysis. Western Blot was used to determine the protein expression of the apoptosis inhibitors livin and caspase-3, the apoptosis-related proteins Bax and Bcl-2, as well as the key protein kinases in the Jak-stat3 signaling pathway, stat3 and p-stat3. Results (1 Bufalin inhibited the proliferation of SW620 cells. IC50 at 24 h, 48 h and 72 h were 76.72 ± 6.21 nmol/L, 34.05 ± 4.21 nmol/L and 16.7 ± 6.37 nmol/L. (2 Bufalin induced SW620 cell cycle arrest and apoptosis, indicated by the appearance of apoptotic bodies; (3 The results from flow cytometry demonstrated that there was cell cycle G2/M phase arrest in 20 nmol/L bufalin treatment group (36.29 ± 2.11% vs 18.39 ± 1.74%, P Conclusions Bufalin not only inhibited the growth of colon cancer SW620 cells, but also induced apoptosis of SW620 cells. Activation of caspase-3, up-regulation of Bax, down-regulation of livin and Bcl-2, as well as inhibition of Jak-stat3 signaling pathway might be the important mechanisms for the bufalin-induced apoptosis.

  2. miR-125b suppresses the proliferation and migration of osteosarcoma cells through down-regulation of STAT3

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Li-hong; Li, Hui; Li, Jin-ping; Zhong, Hui; Zhang, Han-chon; Chen, Jia [Department of Orthopedics, The Second Xiangya Hospital of Central South University, Changsha 410010 (China); Xiao, Tao, E-mail: xiaotaoxyl@163.com [Department of Orthopedics, The Second Xiangya Hospital of Central South University, Changsha 410010 (China)

    2011-12-09

    Highlights: Black-Right-Pointing-Pointer miR-125b is frequently down-regulated in osteosarcoma samples and human osteosarcoma cell lines. Black-Right-Pointing-Pointer Ectopic restoration of miR-125b suppresses cell proliferation and migration in vitro. Black-Right-Pointing-Pointer STAT3 is the direct and functional downstream target of miR-125b. Black-Right-Pointing-Pointer STAT3 can bind to the promoter region of miR-125b and serves as a transactivator. -- Abstract: There is accumulating evidence that microRNAs are involved in multiple processes in development and tumor progression. Abnormally expressed miR-125b was found to play a fundamental role in several types of cancer; however, whether miR-125b participates in regulating the initiation and progress of osteosarcoma still remains unclear. Here we demonstrate that miR-125b is frequently down-regulated in osteosarcoma samples and human osteosarcoma cell lines. The ectopic restoration of miR-125b expression in human osteosarcoma cells suppresses proliferation and migration in vitro and inhibits tumor formation in vivo. We further identified signal transducer and activator of transcription 3 (STAT3) as the direct and functional downstream target of miR-125b. Interestingly, we discovered that the expression of miR-125b is regulated by STAT3 at the level of transcription. STAT3 binds to the promoter region of miR-125b in vitro and serves as a transactivator. Taken together, our findings point to an important role in the molecular etiology of osteosarcoma and suggest that miR-125b is a potential target in the treatment of osteosarcoma.

  3. The effect of STAT3 inhibition on status epilepticus and subsequent spontaneous seizures in the pilocarpine model of acquired epilepsy.

    Science.gov (United States)

    Grabenstatter, H L; Del Angel, Y Cruz; Carlsen, J; Wempe, M F; White, A M; Cogswell, M; Russek, S J; Brooks-Kayal, A R

    2014-02-01

    Pilocarpine-induced status epilepticus (SE), which results in temporal lobe epilepsy (TLE) in rodents, activates the JAK/STAT pathway. In the current study, we evaluate whether brief exposure to a selective inhibitor of the JAK/STAT pathway (WP1066) early after the onset of SE affects the severity of SE or reduces later spontaneous seizure frequency via inhibition of STAT3-regulated gene transcription. Rats that received systemic WP1066 or vehicle at the onset of SE were continuously video-EEG monitored during SE and for one month to assess seizure frequency over time. Protein and/or mRNA levels for pSTAT3, and STAT3-regulated genes including: ICER, Gabra1, c-myc, mcl-1, cyclin D1, and bcl-xl were evaluated in WP1066 and vehicle-treated rats during stages of epileptogenesis to determine the acute effects of WP1066 administration on SE and chronic epilepsy. WP1066 (two 50mg/kg doses) administered within the first hour after onset of SE results in transient inhibition of pSTAT3 and long-term reduction in spontaneous seizure frequency. WP1066 alters the severity of chronic epilepsy without affecting SE or cell death. Early WP1066 administration reduces known downstream targets of STAT3 transcription 24h after SE including cyclin D1 and mcl-1 levels, known for their roles in cell-cycle progression and cell survival, respectively. These findings uncover a potential effect of the JAK/STAT pathway after brain injury that is physiologically important and may provide a new therapeutic target that can be harnessed for the prevention of epilepsy development and/or progression. PMID:24051278

  4. STAT-3 和 MGMT 在人胶质瘤中的表达及意义%Expression and significance of STAT-3 and MGMT in human gllomas

    Institute of Scientific and Technical Information of China (English)

    张龙洲; 王茂德

    2012-01-01

    目的:探讨STAT3和MGMT在人胶质瘤中的表达及其与肿瘤发生和病理分级之间的关系.方法:用免疫组化法检测并比较80例不同病理级别胶质瘤和15例正常脑组织中STAT3和MGMT的表达情况,并对二者表达做相关性分析.结果:STAT3和MGMT在正常脑组织中均未检测到阳性表达,在瘤组织中的表达均随肿瘤病理级别的升高而增高,相关性分析显示二者的表达存在正相关.结论:STAT3在胶质瘤的发生发展中起重要作用,其高表达可能与参与诱导MGMT的高表达有关.%Objective:To explore the expression of STAT —3 and MGMT in human gliomas and its relationship with tumorigenesis and the degrees of malignancy. Methods: Immunohistochemical SP method was employed to study the expression of STAT -3 and MGMT in 80 cases of glioma and 15 cases of normal cerebral tissue used as control group, the relationship of STAT - 3 and MGMT expression was analyzed. Results: Both the expression of STAT - 3 and MGMT increased as the malignant grade increased, at the same time the expression of STAT3 was positively related to that of MGMT. Conclusion: STAT3 may play a vital role in the progression of glioma through induction of MGMT.

  5. STAT3 upregulation in pituitary somatotroph adenomas induces growth hormone hypersecretion

    OpenAIRE

    Zhou, Cuiqi; Jiao, Yonghui; Wang, Renzhi; Ren, Song-Guang; Wawrowsky, Kolja; Melmed, Shlomo

    2015-01-01

    Pituitary somatotroph adenomas result in dysregulated growth hormone (GH) hypersecretion and acromegaly; however, regulatory mechanisms that promote GH hypersecretion remain elusive. Here, we provide evidence that STAT3 directly induces somatotroph tumor cell GH. Evaluation of pituitary tumors revealed that STAT3 expression was enhanced in human GH-secreting adenomas compared with that in nonsecreting pituitary tumors. Moreover, STAT3 and GH expression were concordant in a somatotroph adenoma...

  6. NF-κB and STAT3-key players in liver inflammation and cancer

    Institute of Scientific and Technical Information of China (English)

    Guobin He; Michael Karin

    2011-01-01

    Hepatocellular carcinoma(HCC),the major form of primary liver cancer,is one of the most deadly human cancers.The pathogenesis of HCC is frequently linked with continuous hepatocyte death,inflammatory cell infiltration and compensatory liver regeneration.Understanding the molecular signaling pathways driving or mediating these processes during liver tumorigenesis is important for the identification of novel therapeutic targets for this dreadful disease.The classical IKKβ-dependent NF-κB signaling pathway has been shown to promote hepatocyte survival in both developing and adult livers.In addition,it also plays a crucial role in liver inflammatory responses by controlling the expression of an array of growth factors and cytokines.One of these cytokines is IL-6,which is best known for its role in the liver acute phase response.IL-6 exerts many of its functions via activation of STAT3,a transcription factor found to be important for HCC development.This review will focus on recent studies on the roles of NF-κB and STAT3 in liver cancer.Interactions between the two pathways and their potential as therapeutic targets will also be discussed.

  7. Acteoside-mediates chemoprevention of experimental liver carcinogenesis through STAT-3 regulated oxidative stress and apoptosis.

    Science.gov (United States)

    Peerzada, Kaiser J; Faridi, Aamir H; Sharma, Love; Bhardwaj, Subhash C; Satti, Naresh K; Shashi, Bhushan; Tasduq, Sheikh A

    2016-07-01

    In the absence of an effective therapy against Hepatocellular Carcinoma (HCC), chemoprevention remains an important strategy to circumvent morbidity and mortality. Here, we examined chemopreventive potential of Acteoside (ACT), a plant derived phenylethanoid glycoside against an environmental and dietary carcinogen, diethylnitrosamine (DEN)-induced rat hepatocarcinogenesis. ACT treatment (0.1 and 0.3% supplemented with diet) started 2 weeks before DEN challenge and continued for 18 weeks thereafter, showed a remarkable chemopreventive activity. ACT treatment resulted in reduced HCC nodules. Histopathology showed progressive tissue damage, necrosis (5 weeks), hepatocytic injury (10 weeks), anisonucleosis with presence of prominent nucleoli, sinusidal dilations, and lymphomono nuclear inflammation (18 weeks). Biochemical analysis showed hepatocytic injury (raised ALT, p reactive oxygen species (ROS) levels and prevented mitochondrial membrane potential (MMP) loss. Immunoblotting showed ACT treatment reversed DEN-induced NF-κB, Bax, Cytochrome C, Bcl-2, and Stat-3 levels. We conclude that chemoprotective effect of ACT is mediated by STAT-3 dependent regulation of oxidative stress and apoptosis and ACT has potential to be developed as a chemopreventive agent. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 782-798, 2016. PMID:26990576

  8. CS-04STAT3 INVOLVEMENT IN AN EMT-LIKE PROCESS IN GLIOBLASTOMA BRAIN TUMOR INITIATING CELLS

    OpenAIRE

    Chesnelong, Charles; Luchman, Artee; Gregory Cairncross, J.; Weiss, Samuel

    2014-01-01

    Glioblastoma Multiforme (GBM) is the most aggressive subtype of brain tumour with a median survival of 15 months. Currently, GBM is managed by a combination of maximal safe resection followed by radiation and chemotherapy. However, GBM invariably recurs, highlighting the need to better delineate the basis of recurrent disease and develop novel more effective and targeted therapies. The Signal Transducer and Activator of Transcription 3 (STAT3) is abnormally active in GBM. A growing body of ev...

  9. Disruption of STAT3 signalling promotes KRAS-induced lung tumorigenesis

    Science.gov (United States)

    Grabner, Beatrice; Schramek, Daniel; Mueller, Kristina M.; Moll, Herwig P.; Svinka, Jasmin; Hoffmann, Thomas; Bauer, Eva; Blaas, Leander; Hruschka, Natascha; Zboray, Katalin; Stiedl, Patricia; Nivarthi, Harini; Bogner, Edith; Gruber, Wolfgang; Mohr, Thomas; Zwick, Ralf Harun; Kenner, Lukas; Poli, Valeria; Aberger, Fritz; Stoiber, Dagmar; Egger, Gerda; Esterbauer, Harald; Zuber, Johannes; Moriggl, Richard; Eferl, Robert; Győrffy, Balázs; Penninger, Josef M.; Popper, Helmut; Casanova, Emilio

    2015-01-01

    STAT3 is considered to play an oncogenic role in several malignancies including lung cancer; consequently, targeting STAT3 is currently proposed as therapeutic intervention. Here we demonstrate that STAT3 plays an unexpected tumour-suppressive role in KRAS mutant lung adenocarcinoma (AC). Indeed, lung tissue-specific inactivation of Stat3 in mice results in increased KrasG12D-driven AC initiation and malignant progression leading to markedly reduced survival. Knockdown of STAT3 in xenografted human AC cells increases tumour growth. Clinically, low STAT3 expression levels correlate with poor survival and advanced malignancy in human lung AC patients with smoking history, which are prone to KRAS mutations. Consistently, KRAS mutant lung tumours exhibit reduced STAT3 levels. Mechanistically, we demonstrate that STAT3 controls NF-κB-induced IL-8 expression by sequestering NF-κB within the cytoplasm, thereby inhibiting IL-8-mediated myeloid tumour infiltration and tumour vascularization and hence tumour progression. These results elucidate a novel STAT3–NF-κB–IL-8 axis in KRAS mutant AC with therapeutic and prognostic relevance. PMID:25734337

  10. Resveratrol induces cell cycle arrest and apoptosis in malignant NK cells via JAK2/STAT3 pathway inhibition.

    Directory of Open Access Journals (Sweden)

    Ly Quoc Trung

    Full Text Available Natural killer (NK cell malignancies, particularly aggressive NK cell leukaemias and lymphomas, have poor prognoses. Although recent regimens with L-asparaginase substantially improved outcomes, novel therapeutic approaches are still needed to enhance clinical response. Resveratrol, a naturally occurring polyphenol, has been extensively studied for its anti-inflammatory, cardioprotective and anti-cancer activities. In this study, we investigated the potential anti-tumour activities of resveratrol against the NK cell lines KHYG-1, NKL, NK-92 and NK-YS. Resveratrol induced robust G0/G1 cell cycle arrest, significantly suppressed cell proliferation and induced apoptosis in a dose- and time-dependent manner for all four cell lines. In addition, resveratrol suppressed constitutively active STAT3 in all the cell lines and inhibited JAK2 phosphorylation but had no effect on other upstream mediators of STAT3 activation, such as PTEN, TYK2, and JAK1. Resveratrol also induced downregulation of the anti-apoptotic proteins MCL1 and survivin, two downstream effectors of the STAT3 pathway. Finally, resveratrol induced synergistic effect on the apoptotic and antiproliferative activities of L-asparaginase against KHYG-1, NKL and NK-92 cells. These results suggest that resveratrol may have therapeutic potential against NK cell malignancies. Furthermore, our finding that resveratrol is a bonafide JAK2 inhibitor extends its potential benefits to other diseases with dysregulated JAK2 signaling.

  11. Chikusetsusaponin IVa Butyl Ester (CS-IVa-Be), a Novel IL6R Antagonist, Inhibits IL6/STAT3 Signaling Pathway and Induces Cancer Cell Apoptosis.

    Science.gov (United States)

    Yang, Jie; Qian, Shihui; Cai, Xueting; Lu, Wuguang; Hu, Chunping; Sun, Xiaoyan; Yang, Yang; Yu, Qiang; Gao, S Paul; Cao, Peng

    2016-06-01

    The activation of IL6/STAT3 signaling is associated with the pathogenesis of many cancers. Agents that suppress IL6/STAT3 signaling have cancer-therapeutic potential. In this study, we found that chikusetsusaponin IVa butyl ester (CS-IVa-Be), a triterpenoid saponin extracted from Acanthopanas gracilistylus W.W.Smith, induced cancer cell apoptosis. CS-IVa-Be inhibited constitutive and IL6-induced STAT3 activation, repressed STAT3 DNA-binding activity, STAT3 nuclear translocation, IL6-induced STAT3 luciferase reporter activity, IL6-induced STAT3-regulated antiapoptosis gene expression in MDA-MB-231 cells, and IL6-induced TF-1 cell proliferation. Surprisingly, CS-IVa-Be inhibited IL6 family cytokines rather than other cytokines induced STAT3 activation. Further studies indicated that CS-IVa-Be is an antagonist of IL6 receptor via directly binding to the IL6Rα with a Kd of 663 ± 74 nmol/L and the GP130 (IL6Rβ) with a Kd of 1,660 ± 243 nmol/L, interfering with the binding of IL6 to IL6R (IL6Rα and GP130) in vitro and in cancer cells. The inhibitory effect of CS-IVa-Be on the IL6-IL6Rα-GP130 interaction was relatively specific as CS-IVa-Be showed higher affinity to IL6Rα than to LIFR (Kd: 4,910 ± 1,240 nmol/L) and LeptinR (Kd: 4,990 ± 915 nmol/L). We next demonstrated that CS-IVa-Be not only directly induced cancer cell apoptosis but also sensitized MDA-MB-231 cells to TRAIL-induced apoptosis via upregulating DR5. Our findings suggest that CS-IVa-Be as a novel IL6R antagonist inhibits IL6/STAT3 signaling pathway and sensitizes the MDA-MB-231 cells to TRAIL-induced cell death. Mol Cancer Ther; 15(6); 1190-200. ©2016 AACR.

  12. STAT3 Regulates Proliferation and Survival of CD8+ T Cells: Enhances Effector Responses to HSV-1 Infection, and Inhibits IL-10+ Regulatory CD8+ T Cells in Autoimmune Uveitis

    Directory of Open Access Journals (Sweden)

    Cheng-Rong Yu

    2013-01-01

    Full Text Available STAT3 regulates CD4+ T cell survival and differentiation. However, its effects on CD8+ T cells are not well understood. Here, we show that in comparison to WT CD8+ T cells, STAT3-deficient CD8+ T cells exhibit a preactivated memory-like phenotype, produce more IL-2, proliferate faster, and are more sensitive to activation-induced cell death (AICD. The enhanced proliferation and sensitivity to AICD correlated with downregulation of class-O forkhead transcription factors (FoxO1, FoxO3A, , , Bcl-2, OX-40, and upregulation of FasL, Bax, and Bad. We examined whether STAT3-deficient CD8+ T cells can mount effective response during herpes simplex virus (HSV-1 infection and experimental autoimmune uveitis (EAU. Compared to WT mice, HSV-1-infected STAT3-deficient mice (STAT3KO produced less IFN- and virus-specific KLRG-1+ CD8+ T cells. STAT3KO mice are also resistant to EAU and produced less IL-17-producing Tc17 cells. Resistance of STAT3KO to EAU correlated with marked expansion of IL-10-producing regulatory CD8+ T cells (CD8-Treg implicated in recovery from autoimmune encephalomyelitis. Thus, increases of IL-6-induced STAT3 activation observed during inflammation may inhibit expansion of CD8-Tregs, thereby impeding recovery from uveitis. These results suggest that STAT3 is a potential therapeutic target for upregulating CD8+ T cell-mediated responses to viruses and suggest the successful therapeutic targeting of STAT3 as treatment for uveitis, derived, in part, from promoting CD8-Treg expansion.

  13. STAT3-dependent TXNDC17 expression mediates Taxol resistance through inducing autophagy in human colorectal cancer cells.

    Science.gov (United States)

    Zhang, Zhongde; Wang, Aihua; Li, Hui; Zhi, Hui; Lu, Feng

    2016-06-10

    Taxol (paclitaxel) is one of the taxane class of anticancer drugs as a first-line chemotherapeutic agent against many cancers including colorectal cancer, breast cancer, non-small cell lung cancer, ovarian cancer and so on. It is verified to induce cytotoxicity in a concentration and time-dependent manner. Numerous novel formulations of Taxol have been remanufactured for better therapeutic effect. Though Taxol works as a common anticancer drug for a long time in clinical practice, drug resistance is a major limitation of its long-term administration. In-depth research on drug resistance is still in progress and researchers have made some achievements, however, the mechanism or key molecule related to Taxol resistance in colorectal cancer still remains to be explored. In the present study, we observed that the high expression of TXNDC17 (thioredoxin domain containing 17) was associated with Taxol resistance in colorectal cancer cells. And TXNDC17 mediated Taxol resistance was related with increased basal autophagy level. Taxol exposure induced high levels of phospho-STAT3 (Tyr 705) and TXNDC17; and increase of basal autophagy in colorectal cancer cells. TXNDC17 overexpression cells obtained Taxol resistance and a high level of autophagy, and it is not surprising that stable downregulation of TXNDC17 accordingly reversed these phenomena. Interestingly, STAT3 could similarly work as TXNDC17 in spite of slighter effect compared to TXNDC17. And it has been proved that phospho-STAT3 (Tyr 705) possesses transcriptional regulation activity through forming dimmers. Many research revealed that transcription factor STAT3 affected more than 1000 gene products, and TXNDC17 is predicted to be a target gene of STAT3 at UCSC database. For the first time, we found STAT3 could bind promoter region of TXNDC17 (-623 bp to -58 bp relative to the transcription start site (TSS)) for regulating its expression. These results suggest the possibility that TXNDC17 could play an important role

  14. Progress in the study of relationship between STAT3 and tumor immune escape%STAT3与肿瘤免疫逃逸的研究进展

    Institute of Scientific and Technical Information of China (English)

    祝宝让; 杨武威

    2013-01-01

    Signal transducer and activator of transcription 3 is a dual function of protein in the cytoplasm, which is constitutively activated at a very high frequency in human cancer, on phosphorylation of STAT3 monomers by tyrosine kinases, the monomers dimerized, translocate to the nucleus, and bind to specific promoter sequences, thereby inducing expression of multiple genes associated with cellular proliferation and survival, which is a point of convergence for many oncogenic pathways, play a crucial role in tumor initiation and progression. In recent study, STAT3 has emerged as a critical mediator of tumor immune evasion at multiple levels, provide a target for cancer immunotherapy.%信号转导子与转录激活子3(STAT3)是一种存在于细胞质内的双功能蛋白,可以被多种酪氨酸激酶激活,激活后发生磷酸化,形成二聚体转入细胞核内,调节细胞生长、分化、凋亡相关基因的表达,是多条致癌通路的汇集点,在大多数肿瘤细胞内呈持续性激活,在肿瘤的发生、发展、转移中起了重要作用。近几年的研究表明,STAT3能在很多环节参与调节肿瘤的免疫逃逸,可能是肿瘤免疫治疗的一个重要靶点。

  15. HiJAK’d Signaling; the STAT3 Paradox in Senescence and Cancer Progression

    Energy Technology Data Exchange (ETDEWEB)

    Junk, Damian J.; Bryson, Benjamin L.; Jackson, Mark W., E-mail: mark.w.jackson@case.edu [Department of Pathology, Case Western Reserve University, Case Comprehensive Cancer Center, 2103 Cornell Road, WRB 3-134, Cleveland, OH 44106 (United States)

    2014-03-26

    Clinical and epidemiological data have associated chronic inflammation with cancer progression. Most tumors show evidence of infiltrating immune and inflammatory cells, and chronic inflammatory disorders are known to increase the overall risk of cancer development. While immune cells are often observed in early hyperplastic lesions in vivo, there remains debate over whether these immune cells and the cytokines they produce in the developing hyperplastic microenvironment act to inhibit or facilitate tumor development. The interleukin-6 (IL-6) family of cytokines, which includes IL-6 and oncostatin M (OSM), among others (LIF, CT-1, CNTF, and CLC), are secreted by immune cells, stromal cells, and epithelial cells, and regulate diverse biological processes. Each of the IL-6 family cytokines signals through a distinct receptor complex, yet each receptor complex uses a shared gp130 subunit, which is critical for signal transduction following cytokine binding. Activation of gp130 results in the activation of Signal Transducer and Activator of Transcription 3 (STAT3), and the Mitogen-Activated Protein Kinase (MAPK) and Phosphatidylinositol 3-Kinase (PI3K) signaling cascades. Tumor suppressive signaling can often be observed in normal cells following prolonged STAT3 activation. However, there is mounting evidence that the IL-6 family cytokines can contribute to later stages of tumor progression in many ways. Here we will review how the microenvironmental IL-6 family cytokine OSM influences each stage of the transformation process. We discuss the intrinsic adaptations a developing cancer cell must make in order to tolerate and circumvent OSM-mediated growth suppression, as well as the OSM effectors that are hijacked during tumor expansion and metastasis. We propose that combining current therapies with new ones that suppress the signals generated from the tumor microenvironment will significantly impact an oncologist’s ability to treat cancer.

  16. STAT3 induces transcription of the DNA methyltransferase 1 gene (DNMT1) in malignant T lymphocytes

    DEFF Research Database (Denmark)

    Zhang, Qian; Wang, Hong Y; Woetmann, Anders;

    2006-01-01

    programmed cell death. In turn, inhibition of DNMT1 by a small molecule inhibitor, 5-aza-2-deoxy-cytidine, and 2 DNMT1 antisense DNA oligonucleotides inhibits the phosphorylation of STAT3. These data indicate that STAT3 may in part transform cells by fostering epigenetic silencing of tumor-suppressor genes...

  17. Inhibition of STAT3, FAK and Src mediated signaling reduces cancer stem cell load, tumorigenic potential and metastasis in breast cancer.

    Science.gov (United States)

    Thakur, Ravi; Trivedi, Rachana; Rastogi, Namrata; Singh, Manisha; Mishra, Durga Prasad

    2015-01-01

    Cancer stem cells (CSCs) are responsible for aggressive tumor growth, metastasis and therapy resistance. In this study, we evaluated the effects of Shikonin (Shk) on breast cancer and found its anti-CSC potential. Shk treatment decreased the expression of various epithelial to mesenchymal transition (EMT) and CSC associated markers. Kinase profiling array and western blot analysis indicated that Shk inhibits STAT3, FAK and Src activation. Inhibition of these signaling proteins using standard inhibitors revealed that STAT3 inhibition affected CSCs properties more significantly than FAK or Src inhibition. We observed a significant decrease in cell migration upon FAK and Src inhibition and decrease in invasion upon inhibition of STAT3, FAK and Src. Combined inhibition of STAT3 with Src or FAK reduced the mammosphere formation, migration and invasion more significantly than the individual inhibitions. These observations indicated that the anti-breast cancer properties of Shk are due to its potential to inhibit multiple signaling proteins. Shk also reduced the activation and expression of STAT3, FAK and Src in vivo and reduced tumorigenicity, growth and metastasis of 4T1 cells. Collectively, this study underscores the translational relevance of using a single inhibitor (Shk) for compromising multiple tumor-associated signaling pathways to check cancer metastasis and stem cell load. PMID:25973915

  18. 人胰腺癌细胞STAT3下游耐药相关基因的初步筛选%Preliminary screening of drug resistance-related genes downstream of STAT3 in human pancreatic cancer cell

    Institute of Scientific and Technical Information of China (English)

    杨豪俊; 黄陈; 裘正军; 江弢; 曹俊

    2011-01-01

    目的 利用小分子干扰RNA( siRNA)和基因芯片技术初步筛选人胰腺癌细胞信号转导及转入激活因子3( STAT3)下游耐药相关基因,为探索STAT3调控耐药机制提供依据.方法 利用基因芯片技术比较人胰腺癌细胞SW1990与siRNA沉默STAT3后SW1990细胞中基因表达的差异,初步筛选STAT3下游耐药相关基因.结果 按差异显著性标准从47 000条基因(代表38 500个明晰的基因)中筛选出具有表达差异的基因共有982条(2.55%),其中上调表达2倍的基因有592条,下调表达2倍的基因有390条.与耐药相关基因有:显著上调的拓扑异构酶AⅡα( TOPOⅡα)、肿瘤坏死因子凋亡诱导相关配体(TRAIL);显著下调的富半胱氨酸61( CYR61),Ras肿瘤基因家族成员(RAP1 A),bcl-2相关抗凋亡基因(BAG1),囊性纤维化跨膜转导调节因子(CFTR).结论 胰腺癌耐药是一个多基因、多通路相互作用的结果.应用siRNA技术沉默STAT3基因后,有6条耐药相关基因发生改变.为进一步研究STAT3与胰腺癌耐药的关系提供新的线索,也为胰腺癌的治疗提供新的思路.%Objective To preliminarily screen out the drug resistance-related genes downstream of signal transducer and activator of transcription 3 ( STAT3 ) in human pancreatic cancer cell by small interfering RNA ( siRNA) and gene chip technique, with the purpose of providing a basis for studying the mechanism of STAT3-associated drug resistance. Methods The differentially expressed genes between the human pancreatic SW1990 cells of wild-type STAT3 gene and STAT3 gene silenced by siRNA were compared after using gene chip technique to preliminarily screen out the drug resistance-related genes downstream of STAT3. Results Nine hundred and eighty-two (2. 55% ) differentially expressed genes were screened from the 47000 genes represented on the microarray according to the criterion of significant difference, of which, 592 genes were up-regulated by 2-fold and 390 genes

  19. GREB1 functions as a growth promoter and is modulated by IL6/STAT3 in breast cancer.

    Directory of Open Access Journals (Sweden)

    Mingli Liu

    Full Text Available BACKGROUND: Growth Regulation by Estrogen in Breast cancer (GREB1 was an estrogen receptor (ER target gene, and GREB1 expression inversely correlated with HER2 status, possibly as a surrogate marker for ER status and a predictor for tamoxifen resistance in breast cancer patients. In the present study, we examine the function and regulation of GREB1 in breast cancer, with the goal to develop GREB1 as a biomarker in breast cancer with de novo and acquired tamoxifen resistance. METHODS: We overexpressed GREB1 using adenovirus containing the full length GREB1 cDNA (Ad-GREB1 in breast cancer cell lines. The soft agar assay was used as a measure of anchorage independent growth. The effects of GREB1 on cell proliferation in MCF-7 cells transduced with Ad-GREB1 were also measured by the me olic activity using AlamarBlue assay. We tested whether there was interaction between STAT3 and ER, which could repress GREB1 expression by immunoprecipitation assay. The effects of IL-6/JAK/STAT3 cascade activation on estrogen-induced GREB1 promoter activity were determined by luciferase assay and those on gene expression were measured by real time reverse transcription polymerase chain reaction (qRT-PCR. RESULTS: We found that the ability of breast cancer cells to grow in soft agar is enhanced following GREB1 transfection. In MCF-7 cells transduced with Ad-GREB1 or transfected with siRNA GREB1, the metabolic activity was increased or completely abolished, suggesting that GREB1 may function as a growth promoter in breast cancer. E2 treatment increased GREB1 promoter luciferase activity. IL-6 inhibited E2-induced GREB1 transcription activity and GREB1 mRNA expression. Constitutively expressing active STAT3 construct (STAT3-C dramatically decreased GREB1 transcription. CONCLUSIONS: These data indicate that overexpression of GREB1 promotes cell proliferation and increases the clonogenic ability in breast cancer cells. Moreover, Il6/STAT3 modulates estrogen-induced GREB1

  20. TLR4 signaling promotes a COX-2/PGE2/STAT3 positive feedback loop in hepatocellular carcinoma (HCC) cells

    Science.gov (United States)

    Lin, Ang; Wang, Guan; Zhao, Huajun; Zhang, Yuyi; Han, Qiuju; Zhang, Cai; Tian, Zhigang; Zhang, Jian

    2016-01-01

    ABSTRACT Toll-like receptors (TLRs) can be expressed by tumor cells, and each TLR exhibits different biological functions. Evidences showed the activation of some certain TLRs could promote tumor progression. One of which TLR4 has been found to promote hepatocellular carcinoma (HCC) cells proliferation, but the detailed mechanism is still unknown. In the present study, we verified that TLR4 was functionally expressed on HCC cells, and TLR4 agonist lipopolysaccharide (LPS) could stimulate the proliferation and clone formation of HCC cells. Most importantly, we found a COX-2/PGE2/STAT3 positive feedback loop exists in HCC cells, which could be provoked by TLR4 activation. Consistently, the expression of TLR4, COX-2 and p-STAT3Y705 was positively correlated with each other in liver tumor tissues from patients with primary HCC. Further investigation demonstrated this loop played a dominant role in TLR4-induced HCC cell proliferation and multidrug resistance (MDR) to chemotherapy. Inhibition of TLR4 or COX-2/PGE2/STAT3 loop would attenuate LPS-induced inflammation and proliferation of HCC cells, and enhance the sensitivity of HCC cells to chemotherapeutics in vitro. By using a primary HCC model, we observed COX-2/PGE2/STAT3 loop was significantly blocked in TLR4−/− mice compared to wild type mice, and there was no obvious tumorgenesis sign in TLR4−/− mice. Therefore, these findings provided the precise molecular mechanism of TLR4 signaling pathway involved in HCC progress, and suggested that TLR4 may be a promising target for HCC treatment. PMID:27057441

  1. Dietary iron enhances colonic inflammation and IL-6/IL-11-Stat3 signaling promoting colonic tumor development in mice.

    Directory of Open Access Journals (Sweden)

    Anita C G Chua

    Full Text Available Chronic intestinal inflammation and high dietary iron are associated with colorectal cancer development. The role of Stat3 activation in iron-induced colonic inflammation and tumorigenesis was investigated in a mouse model of inflammation-associated colorectal cancer. Mice, fed either an iron-supplemented or control diet, were treated with azoxymethane and dextran sodium sulfate (DSS. Intestinal inflammation and tumor development were assessed by endoscopy and histology, gene expression by real-time PCR, Stat3 phosphorylation by immunoblot, cytokines by ELISA and apoptosis by TUNEL assay. Colonic inflammation was more severe in mice fed an iron-supplemented compared with a control diet one week post-DSS treatment, with enhanced colonic IL-6 and IL-11 release and Stat3 phosphorylation. Both IL-6 and ferritin, the iron storage protein, co-localized with macrophages suggesting iron may act directly on IL-6 producing-macrophages. Iron increased DSS-induced colonic epithelial cell proliferation and apoptosis consistent with enhanced mucosal damage. DSS-treated mice developed anemia that was not alleviated by dietary iron supplementation. Six weeks post-DSS treatment, iron-supplemented mice developed more and larger colonic tumors compared with control mice. Intratumoral IL-6 and IL-11 expression increased in DSS-treated mice and IL-6, and possibly IL-11, were enhanced by dietary iron. Gene expression of iron importers, divalent metal transporter 1 and transferrin receptor 1, increased and iron exporter, ferroportin, decreased in colonic tumors suggesting increased iron uptake. Dietary iron and colonic inflammation synergistically activated colonic IL-6/IL-11-Stat3 signaling promoting tumorigenesis. Oral iron therapy may be detrimental in inflammatory bowel disease since it may exacerbate colonic inflammation and increase colorectal cancer risk.

  2. Interleukin-6-induced STAT3 transactivation and Ser(727) phosphorylation involves Vav, Rac-1 and the kinase SEK-1/MKK-4 as signal transduction components

    NARCIS (Netherlands)

    Schuringa, JJ; Jonk, LJC; Dokter, WHA; Vellenga, E; Kruijer, W

    2000-01-01

    In the present study, signal transducer and activator of transcription 3 (STAT3) Ser(727) phosphorylation and transactivation was investigated in relation to activation of mitogen-activated protein (MAP) kinase family members including extracellular-signal-regulated protein kinase (ERK)-1, c-Jun N-t

  3. Luteolin decreases invasiveness, deactivates STAT3 signaling, and reverses interleukin-6 induced epithelial–mesenchymal transition and matrix metalloproteinase secretion of pancreatic cancer cells

    Directory of Open Access Journals (Sweden)

    Huang XC

    2015-10-01

    Full Text Available Xince Huang,1 Shengjie Dai,1 Juji Dai,1 Yuwu Xiao,1 Yongyu Bai,1 Bicheng Chen,1,2 Mengtao Zhou1 1Department of Surgery, The First Affiliated Hospital, Wenzhou Medical University, Wenzhou, Zhejiang Province, People’s Republic of China; 2Zhejiang Provincial Top Key Discipline in Surgery, Wenzhou Key Laboratory of Surgery, Wenzhou, Zhejiang Province, People’s Republic of China Abstract: Luteolin, a flavone, has been shown to exhibit anticancer properties. Here, we investigated whether luteolin affects epithelial–mesenchymal transition (EMT and invasiveness of pancreatic cancer cell lines and their underlying mechanism. Pancreatic cancer cell lines PANC-1 and SW1990 were used in our study, and their EMT characters, matrix metalloproteinase (MMP expression level, invasiveness, and signal transducer and activator of transcription 3 (STAT3 activity were determined after luteolin treatment. We also treated pancreatic cancer cells with interleukin-6 (IL-6 to see whether IL-6-induced activation of STAT3, EMT, and MMP secretion was affected by luteolin. We found that luteolin inhibits EMT and MMP2, MMP7, and MMP9 expression in a dose-dependent manner, similar to STAT3 signaling. Through Transwell assay, we found that invasiveness of pancreatic cancer cells was inhibited by luteolin. EMT characters and MMP secretion increase with STAT3 activity after IL-6 treatment and these effects, caused by IL-6, were inhibited by luteolin. We concluded that luteolin inhibits invasiveness of pancreatic cancer cells, and we speculated that luteolin inhibits EMT and MMP secretion likely through deactivation of STAT3 signaling. Luteolin has potential antitumor effects and merits further investigation. Keywords: epithelial–mesenchymal transition, matrix metalloproteinase, luteolin, STAT3

  4. Effects of mTOR-STAT3 on the migra=tion and invasion abilities of hepatoma cell and mTOR-STAT3 expression in liver cancer

    Institute of Scientific and Technical Information of China (English)

    Xia Pu; Qing-Xi Guo; Han-An Long; Cheng-Wan Yang

    2014-01-01

    Objective:To investigate the effects of mTOR-STAT3 pathway on the invasion and migration of hepatoma cell.Methods:mTOR andSTAT3 expresssion in the hepatocellular carcinoma cell lineHepG2 and normal liver cell lineL02 were detected by reverse transcriptionPCR(RT-PCR) and western blotting.The migration and invasion abilities of cells and expression ofSTAT3 were detected by scratch adhesion test and transwell migration assays, after siRNA transfection blocking mTOR expression ofHepG2 cells.Results:TheHepG2 cells expression is higher compared with normal cellsL02 expression.Western blotting assay showed the mTOR expression was blocked, whileSTAT3 expression was also decreased, after the siRNA transfection ofHepG2 cells.The migration(scratch adhesion test) and invasion(transwell assays) abilitiesofHepG2 cells which the mTOR expression was blocked by siRNA interference were significantly decreased (P<0.05).Conclusion: mTORSTAT3 expression in hepatoma cellsHepG2 was significantly higher than that in normal liver cells. mTOR blocking can reduce the expression ofSTAT3, which is also closely related to the invasion and metastasis of liver cancer cells.

  5. Gingko biloba extract (Ginaton) ameliorates dextran sulfate sodium (DSS)-induced acute experimental colitis in mice via reducing IL-6/STAT3 and IL-23/IL-17.

    Science.gov (United States)

    Sun, Yan; Lin, Lian-Jie; Lin, Yan; Sang, Li-Xuan; Jiang, Min; Zheng, Chang-Qing

    2015-01-01

    This study explored the underlying mechanism of Gingko biloba extract (Ginaton) on dextran sulfate sodium (DSS)-induced acute experimental colitis in mice. 40 male C57BL/6 mice were randomly divided into four groups: normal control group, Ginaton group, Ginaton treatment group, and DSS group. After 7 days administration, mice were sacrificed and colons were collected for H-E staining, immunohistochemistry, real-time PCR and Western blot. By observing clinical disease activity and histological damage, we assessed the effect of Ginaton on DSS-induced acute experimental colitis in mice and observed the effect of Ginaton on normal mice. We also explored the specific mechanism of Ginaton on DSS-induced acute experimental colitis in mice through examining the expression of inflammatory related mediators (gp130, STAT3, p-STAT3, ROR-γt) and cytokines (IL-6, IL-17, IL-23). Ginaton-treated DSS mice showed significant improvement over untreated DSS mice. Specifically, Ginaton improved clinical disease activity (DAI score, weight closs, colon shortening, and bloody stool) and histological damage, and reduced the expression of inflammatory-related mediators (p-STAT3, gp130, ROR-γt) and cytokines (IL-6, IL-17, IL-23). In addition, clinical disease activity, histological damage, the expression of inflammatory related mediators (STAT3, p-STAT3, gp130, ROR-t) and cytokines (IL-6, IL-17, IL-23) in mice of Ginaton group were similar to normal control group. In conclusion, Ginaton ameliorates DSS-induced acute experimental colitis in mice by reducing IL-17 production, which is at least partly involved in inhibiting IL-6/STAT3 signaling pathway and IL-23/IL-17 axis. Moreover, Ginaton itself does not cause inflammatory change in normal mice. These results support that Ginaton can be as a potential clinical treatment for ulcerative colitis (UC).

  6. Herbal Extract SH003 Suppresses Tumor Growth and Metastasis of MDA-MB-231 Breast Cancer Cells by Inhibiting STAT3-IL-6 Signaling

    Directory of Open Access Journals (Sweden)

    Youn Kyung Choi

    2014-01-01

    Full Text Available Cancer inflammation promotes cancer progression, resulting in a high risk of cancer. Here, we demonstrate that our new herbal extract, SH003, suppresses both tumor growth and metastasis of MDA-MB-231 breast cancer cells via inhibiting STAT3-IL-6 signaling path. Our new herbal formula, SH003, mixed extract from Astragalus membranaceus, Angelica gigas, and Trichosanthes kirilowii Maximowicz, suppressed MDA-MB-231 tumor growth and lung metastasis in vivo and reduced the viability and metastatic abilities of MDA-MB-231 cells in vitro. Furthermore, SH003 inhibited STAT3 activation, which resulted in a reduction of IL-6 production. Therefore, we conclude that SH003 suppresses highly metastatic breast cancer growth and metastasis by inhibiting STAT3-IL-6 signaling path.

  7. Molecular Cross-Talk between the NFκB and STAT3 Signaling Pathways in Head and Neck Squamous Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Cristiane H. Squarize

    2006-09-01

    Full Text Available The development of head and neck squamous cell carcinoma (HNSCC involves the accumulation of genetic and epigenetic alterations in tumor-suppressor proteins, together with the persistent activation of growth-promoting signaling pathways. The activation of epidermal growth factor receptor (EGFR is a frequent event in HNSCC. However, EGFR-independent mechanisms also contribute to the activation of key intracellular signaling routes, including signal transducer and activator of transcription-3 (STAT3, nuclear factor κB (NFκB, and Akt. Indeed, the autocrine activation of the gp130 cytokine receptor in HNSCC cells by tumor-released cytokines, such as IL-6, can result in the EGFR-independent activation of STAT3. In this study, we explored the nature of the molecular mechanism underlying enhanced IL-6 secretion in HNSCC cells. We found that HNSCC cells display an increased activity of the IL-6 promoter, which is dependent on the presence of an intact NFκB site. Furthermore, NFκB inhibition downregulated IL-6 gene and protein expression, and decreased the release of multiple cytokines. Interestingly, interfering with NFκB function also prevented the autocrine/paracrine activation of STAT3 in HNSCC cells. These findings demonstrate a cross-talk between the NFκB and the STAT3 signaling systems, and support the emerging notion that HNSCC results from the aberrant activity of a signaling network.

  8. Inlfuence of Compound Shougong Powder on JAK2-STAT3 Signaling Pathway in Mice with Lewis Lung Cancer

    Institute of Scientific and Technical Information of China (English)

    SHEN Di; LI Chong-hui

    2014-01-01

    Objective:To observe the inlfuence of Compound Shougong Powder on JAK2-STAT3 signaling pathway in mice with Lewis lung cancer. Methods: Fifty C57BL/6J mice were inoculated with Lewis lung cancer cell line according to the conventional method, 40 mice bearing cancer successfully were selected 6 d later and randomly divided into 5groups, namely negative control group, cis-platinum group, high-dose Compound Shougong Powder group, middle-dose Compound Shougong Powder group and low-dose Compound Shougong Powder group, 8 mice in each group. Negative control group was drenched with normal saline (NS). Compound Shougong Powder groups were drenched with Compound Shougong Powder, 4 mg/kg for high-dose group, 2 mg/kg for middle-dose group, 1 mg/kg for low-dose group, once per day for 14 d; cis-platinum group was orally administrated 4 mg/kg/w, intraperitoneal injection of 0.1 mL for each, once per week for 2 weeks. Mice's responses to the treatment, activity levels, mental states and so on during the treatment were observed, tumor inhibition rate was calculated, pathomorphological changes of tumor tissues were observed under light microscope after HE staining, and the expression levels of JAK2 and STAT3 proteins were detected by Western Blot. Results: After drug administration, smooth, glossy body hair and good spirit were observed in cisplatin group and high-dose Compound Shougong Powder group; glossier body hair and less activity level in middle- and low- dose Compound Shougong Powder group, and great toxic and side effects, reduced activity level and weary spirit in negative control group. The tumor inhibition rate of cisplatin group, high-, middle- and low-dose Compound Shougong Powder group and negative control group was 57.69%, 53.53%, 48.40%, 38.46% and 38.46%, respectively. The expression levels of JAK2 and STAT3 proteins in drug groups showed decreases to different degrees, and the decreases of JAK2 were more signiifcant. Conclusion: Compound Shougong Powder can

  9. The Influence of Compound Shougong Powder on JAK2-STAT3 Signaling Pathway in Mice with Lewis Lung Cancer

    Directory of Open Access Journals (Sweden)

    SHEN Di

    2014-12-01

    Full Text Available Objective: To observe the influence of Compound Shougong Powder on JAK2-STAT3 signaling pathway in mice with Lewis lung cancer. Methods: Fifty C57BL/6J mice were inoculated with Lewis lung cancer cell line according to the conventional method, 40 mice bearing cancer successfully were selected 6 d later and randomly divided into 5groups, namely negative control group, cis-platinum group, high-dose Compound Shougong Powder group, middle-dose Compound Shougong Powder group and low-dose Compound Shougong Powder group, 8 mice in each group. Negative control group was drenched with normal saline (NS. Compound Shougong Powder groups were drenched with Compound Shougong Powder, 4 mg/kg for high-dose group, 2 mg/kg for middle-dose group, 1 mg/kg for low-dose group, once per day for 14 d; cis-platinum group was orally administrated 4 mg/kg/w, intraperitoneal injection of 0.1 mL for each, once per week for 2 weeks. Mice’s responses to the treatment, activity levels, mental states and so on during the treatment were observed, tumor inhibition rate was calculated, pathomorphological changes of tumor tissues were observed under light microscope after HE staining, and the expression levels of JAK2 and STAT3 proteins were detected by Western Blot. Results: After drug administration, smooth, glossy body hair and good spirit were observed in cisplatin group and high-dose Compound Shougong Powder group; glossier body hair and less activity level in middle- and low- dose Compound Shougong Powder group, and great toxic and side effects, reduced activity level and weary spirit in negative control group. The tumor inhibition rate of cisplatin group, high-, middle- and low-dose Compound Shougong Powder group and negative control group was 57.69%, 53.53%, 48.40%, 38.46% and 38.46%, respectively. The expression levels of JAK2 and STAT3 proteins in drug groups showed decreases to different degrees, and the decreases of JAK2 were more significant. Conclusion: Compound

  10. Structure and boosting activity of a starch-degrading lytic polysaccharide monooxygenase

    DEFF Research Database (Denmark)

    Lo Leggio, Leila; Simmons, Thomas J.; Poulsen, Jens-Christian Navarro;

    2015-01-01

    the activity, spectroscopy and three-dimensional structure of a starch-active LPMO, a representative of the new CAZy AA13 family. We demonstrate that these enzymes generate aldonic acid-terminated malto-oligosaccharides from retrograded starch and boost significantly the conversion of this recalcitrant...... substrate to maltose by β-amylase. The detailed structure of the enzyme's active site yields insights into the mechanism of action of this important class of enzymes....

  11. PLGA nanoparticles codeliver paclitaxel and Stat3 siRNA to overcome cellular resistance in lung cancer cells

    Directory of Open Access Journals (Sweden)

    Su WP

    2012-08-01

    Full Text Available Wen-Pin Su,1,2 Fong-Yu Cheng,3 Dar-Bin Shieh,3–6 Chen-Sheng Yeh,5–7 Wu-Chou Su1,2,81Graduate Institute of Clinical Medicine, College of Medicine, National Cheng Kung University; 2Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University; 3Institute of Oral Medicine, College of Medicine, National Cheng Kung University; 4Department of Stomatology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University; 5Advanced Optoelectronic Technology Center; 6Center for Frontier Materials and Micro/Nano Science and Technology, and 7Department of Chemistry, National Cheng Kung University; 8Cancer Center, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.Abstract: Background: Effective cancer chemotherapy remains an important issue in cancer treatment, and signal transducer and activator of transcription-3 (Stat3 activation leads to cellular resistance of anticancer agents. Polymers are ideal vectors to carry both chemotherapeutics and small interfering ribonucleic acid (siRNA to enhance antitumor efficacy. In this paper, poly(lactic-co-glycolic acid (PLGA nanoparticles loaded with paclitaxel and Stat3 siRNA were successfully synthesized, and their applications in cancer cells were investigated.Methods: Firstly, paclitaxel was enclosed by PLGA nanoparticles through solvent evaporation. They were then coated with cationic polyethylenimine polymer (PLGA-PEI-TAX, enabling it to carry Stat3 siRNA on its surface through electrostatic interactions (PLGA-PEI-TAX-S3SI. The size, zeta potential, deliver efficacy, and release profile of the PLGA nanocomplexes were characterized in vitro. The cellular uptake, intracellular nanoparticle trajectory, and subsequent cellular events were evaluated after treatment with various PLGA nanocomplexes in human lung cancer A549 cells and A549-derived paclitaxel

  12. Curcumin ameliorates neuropathic pain by down-regulating spinal IL-1β via suppressing astroglial NALP1 inflammasome and JAK2-STAT3 signalling

    Science.gov (United States)

    Liu, Shenbin; Li, Qian; Zhang, Meng-Ting; Mao-Ying, Qi-Liang; Hu, Lang-Yue; Wu, Gen-Cheng; Mi, Wen-Li; Wang, Yan-Qing

    2016-01-01

    Curcumin has been shown to possess strong anti-inflammatory activity in many diseases. It has been demonstrated that the janus kinase 2 (JAK2)-signal transducer and activator of transcription 3 (STAT3) cascade and the NAcht leucine-rich-repeat protein 1 (NALP1) inflammasome are important for the synthesis of Pro-Interleukin (IL)-1β and the processing of the inactive protein to its mature form, which plays an active role in the pathogenesis of neuropathic pain. The present study showed that repeated intraperitoneal injection of curcumin ameliorated SNI-induced mechanical and cold allodynia in a dose-dependent manner and inhibited the elevation of spinal mature IL-1β protein levels. Additionally, repeated curcumin treatment significantly inhibited the aggregation of the NALP1 inflammasome and the activation of the JAK2-STAT3 cascade in spinal astrocytes. Furthermore, the genetic down-regulation of NALP1 inflammasome activation by NALP1 siRNA and the pharmacological inhibition of the JAK2-STAT3 cascade by AG490 markedly inhibited IL-1β maturation and Pro-IL-1β synthesis, respectively, and reduced SNI-induced pain hypersensitivity. Our results suggest that curcumin attenuated neuropathic pain and down-regulated the production of spinal mature IL-1β by inhibiting the aggregation of NALP1 inflammasome and the activation of the JAK2-STAT3 cascade in astrocytes. PMID:27381056

  13. Activation of the reward system boosts innate and adaptive immunity.

    Science.gov (United States)

    Ben-Shaanan, Tamar L; Azulay-Debby, Hilla; Dubovik, Tania; Starosvetsky, Elina; Korin, Ben; Schiller, Maya; Green, Nathaniel L; Admon, Yasmin; Hakim, Fahed; Shen-Orr, Shai S; Rolls, Asya

    2016-08-01

    Positive expectations contribute to the clinical benefits of the placebo effect. Such positive expectations are mediated by the brain's reward system; however, it remains unknown whether and how reward system activation affects the body's physiology and, specifically, immunity. Here we show that activation of the ventral tegmental area (VTA), a key component of the reward system, strengthens immunological host defense. We used 'designer receptors exclusively activated by designer drugs' (DREADDs) to directly activate dopaminergic neurons in the mouse VTA and characterized the subsequent immune response after exposure to bacteria (Escherichia coli), using time-of-flight mass cytometry (CyTOF) and functional assays. We found an increase in innate and adaptive immune responses that were manifested by enhanced antibacterial activity of monocytes and macrophages, reduced in vivo bacterial load and a heightened T cell response in the mouse model of delayed-type hypersensitivity. By chemically ablating the sympathetic nervous system (SNS), we showed that the reward system's effects on immunity are, at least partly, mediated by the SNS. Thus, our findings establish a causal relationship between the activity of the VTA and the immune response to bacterial infection. PMID:27376577

  14. Region 752-761 of STAT3 is critical for SRC-1 recruitment and Ser727 phosphorylation.

    Science.gov (United States)

    Zhao, Hong; Nakajima, Ryota; Kunimoto, Hiroyuki; Sasaki, Takanori; Kojima, Hirotada; Nakajima, Koichi

    2004-12-10

    STAT3 regulates many target genes in response to cytokines and growth factors. To study the mechanisms of STAT3-dependent transcription, we established several cell lines in which HepG2-STAT3-knockdown cells were reconstituted with a variety of STAT3 mutants. Using these cell lines, we found that truncated STAT3(1-750), but not STAT3(1-761), could not recruit SRC-1/NcoA-1 and was not phosphorylated on Ser727. Furthermore, mutation of STAT3 L755 and F757 to alanines caused the loss of STAT3-dependent SRC-1 recruitment, leaving Ser727 phosphorylation intact. Consistent with this, the STAT3-L755A/F757A mutant showed no increase in acetylated histone H3 at Lys14 and a decreased level of RNA polymerase II recruited to the target gene promoter, although p300 recruitment and histone H4 acetylation were intact. This mutant also lost responsiveness to co-expressed SRC-1. Thus, the conserved STAT3 region from 752 to 761, called STAT3 CR2, plays critical roles in STAT3-dependent transcription by recruiting SRC-1 and allowing Ser727 phosphorylation. PMID:15530426

  15. INVESTIGATION OF LATENT NUCLEAR LOCALIZATION SEQUENCE(NLS) OF STAT3

    Institute of Scientific and Technical Information of China (English)

    杨镇珲; 李惠; 叶中德; 冯健男; 沈倍奋

    2004-01-01

    Objective: To investigate the latent nuclear localization sequence (NLS) OF STAT3. Methods: Clustal X (1.81) was used to alignment the DNA binding domain of the STAT family. According to structure characters, corresponding expression plasmids were constructed via oligonucleotides designed with gene tool software. Through in vitro transfection, images were observed with laser confocal microscopy. Results: homology positions of arginine and lysine were found in DNA binding domain of the stat family. The wild type-STAT3 proteins primarily localized in the cytoplasm and translocated into the nucleus after interleukin-6 stimulation. However, the truncated mutant of DSTAT3-GFP protein was exclusively expressed in the cytoplasm. Conclusion: The potential NLS in the DNA binding domain of STAT3 is exposed to nuclear importing receptor when cells are stinulated by cytokine, which promotes the translocation of STAT3 into nuclear.

  16. Negative emotions boost user activity at BBC forum

    Science.gov (United States)

    Chmiel, Anna; Sobkowicz, Pawel; Sienkiewicz, Julian; Paltoglou, Georgios; Buckley, Kevan; Thelwall, Mike; Hołyst, Janusz A.

    2011-08-01

    We present an empirical study of user activity in online BBC discussion forums, measured by the number of posts written by individual debaters and the average sentiment of these posts. Nearly 2.5 million posts from over 18 thousand users were investigated. Scale-free distributions were observed for activity in individual discussion threads as well as for overall activity. The number of unique users in a thread normalized by the thread length decays with thread length, suggesting that thread life is sustained by mutual discussions rather than by independent comments. Automatic sentiment analysis shows that most posts contain negative emotions and the most active users in individual threads express predominantly negative sentiments. It follows that the average emotion of longer threads is more negative and that threads can be sustained by negative comments. An agent-based computer simulation model has been used to reproduce several essential characteristics of the analyzed system. The model stresses the role of discussions between users, especially emotionally laden quarrels between supporters of opposite opinions, and represents many observed statistics of the forum.

  17. The new therapy strategy of glioma--STAT3 RNAi combined with traditional radiotherapy

    International Nuclear Information System (INIS)

    STAT3 is an important inhibitor of apoptosis gene discovered in recent years, with a bifunction of inhibiting apoptosis and getting involved in cell cycle control. A lot of basic and clinical researches have found the relation between STAT3 gene and sensitivity to chemotherapy and radiotherapy. Researches have been focused on knocking down its expression to inhibit the growth of tumor and improve the sensitivity to radiotherapy and chemotherapy, especialy by RNAi approach. (authors)

  18. Transcutaneous iontophoretic delivery of STAT3 siRNA using layer-by-layer chitosan coated gold nanoparticles to treat melanoma.

    Science.gov (United States)

    Labala, Suman; Jose, Anup; Venuganti, Venkata Vamsi Krishna

    2016-10-01

    Overexpression of signal transducer and activator of transcription 3 (STAT3) protein prevents apoptosis and enhances proliferation of melanocytes. The aim of this study was to investigate the feasibility of using layer-by-layer assembled gold nanoparticles (LbL-AuNP) as a carrier for iontophoretic delivery of STAT3 siRNA to treat melanoma. Chitosan coated AuNP (AuNP-CS) were prepared by direct reduction of HAuCl4 in the presence of chitosan. The AuNP-CS were then sequentially layered with siRNA and chitosan to form AuNP-CS/siRNA/CS. STAT3 siRNA replaced with scrambled siRNA or sodium alginate were used as controls. The average particle size and zeta-potential of the prepared LbL-AuNP were 150±10nm (PDI: 0.41±0.06) and 35±6mV, respectively. In vitro studies in B16F10 murine melanoma cells showed that AuNP-CS/siRNA/CS inhibited the cell growth by 49.0±0.6% and 66.0±0.2% at 0.25nM and 0.5nM STAT3 siRNA concentration, respectively. Fluorescence microscopy and flow cytometry studies showed a time dependent cell uptake of the LbL-AuNP up to 120min. Clathrin mediated endocytosis was found to be the predominant cell uptake mechanism for LbL-AuNP. STAT3 siRNA loaded LbL-AuNP reduced the STAT3 protein expression by 47.3% in B16F10 cells. Similarly, apoptosis assay showed 29% and 44% of early and late apoptotic events, respectively after treatment with STAT3 siRNA loaded LbL-AuNP. Confocal microscope and skin cryosections showed that application of 0.47mA/cm(2) of anodal iontophoresis enhanced the skin penetration of LbL-AuNP to reach viable epidermis. In conclusion, layer-by-layer chitosan coated AuNP can be developed as a carrier for iontophoretic delivery of STAT3 siRNA to treat melanoma. PMID:27318964

  19. Human Cytomegalovirus Immediate-Early 1 Protein Rewires Upstream STAT3 to Downstream STAT1 Signaling Switching an IL6-Type to an IFNγ-Like Response.

    Directory of Open Access Journals (Sweden)

    Thomas Harwardt

    2016-07-01

    Full Text Available The human cytomegalovirus (hCMV major immediate-early 1 protein (IE1 is best known for activating transcription to facilitate viral replication. Here we present transcriptome data indicating that IE1 is as significant a repressor as it is an activator of host gene expression. Human cells induced to express IE1 exhibit global repression of IL6- and oncostatin M-responsive STAT3 target genes. This repression is followed by STAT1 phosphorylation and activation of STAT1 target genes normally induced by IFNγ. The observed repression and subsequent activation are both mediated through the same region (amino acids 410 to 445 in the C-terminal domain of IE1, and this region serves as a binding site for STAT3. Depletion of STAT3 phenocopies the STAT1-dependent IFNγ-like response to IE1. In contrast, depletion of the IL6 receptor (IL6ST or the STAT kinase JAK1 prevents this response. Accordingly, treatment with IL6 leads to prolonged STAT1 instead of STAT3 activation in wild-type IE1 expressing cells, but not in cells expressing a mutant protein (IE1dl410-420 deficient for STAT3 binding. A very similar STAT1-directed response to IL6 is also present in cells infected with a wild-type or revertant hCMV, but not an IE1dl410-420 mutant virus, and this response results in restricted viral replication. We conclude that IE1 is sufficient and necessary to rewire upstream IL6-type to downstream IFNγ-like signaling, two pathways linked to opposing actions, resulting in repressed STAT3- and activated STAT1-responsive genes. These findings relate transcriptional repressor and activator functions of IE1 and suggest unexpected outcomes relevant to viral pathogenesis in response to cytokines or growth factors that signal through the IL6ST-JAK1-STAT3 axis in hCMV-infected cells. Our results also reveal that IE1, a protein considered to be a key activator of the hCMV productive cycle, has an unanticipated role in tempering viral replication.

  20. Hedyotis diffusa Willd Inhibits Colorectal Cancer Growth in Vivo via Inhibition of STAT3 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Jun Peng

    2012-05-01

    Full Text Available Signal Transducer and Activator of Transcription 3 (STAT3, a common oncogenic mediator, is constitutively activated in many types of human cancers; therefore it is a major focus in the development of novel anti-cancer agents. Hedyotis diffusa Willd has been used as a major component in several Chinese medicine formulas for the clinical treatment of colorectal cancer (CRC. However, the precise mechanism of its anti-tumor activity remains largely unclear. Using a CRC mouse xenograft model, in the present study we evaluated the effect of the ethanol extract of Hedyotis diffusa Willd (EEHDW on tumor growth in vivo and investigated the underlying molecular mechanisms. We found that EEHDW reduced tumor volume and tumor weight, but had no effect on body weight gain in CRC mice, demonstrating that EEHDW can inhibit CRC growth in vivo without apparent adverse effect. In addition, EEHDW treatment suppressed STAT3 phosphorylation in tumor tissues, which in turn resulted in the promotion of cancer cell apoptosis and inhibition of proliferation. Moreover, EEHDW treatment altered the expression pattern of several important target genes of the STAT3 signaling pathway, i.e., decreased expression of Cyclin D1, CDK4 and Bcl-2 as well as up-regulated p21 and Bax. These results suggest that suppression of the STAT3 pathway might be one of the mechanisms by which EEHDW treats colorectal cancer.

  1. Inhibition of Stat3 by peptide aptamer rS3-PA enhances growth suppressive effects of irinotecan on colorectal cancer cells.

    Science.gov (United States)

    Weber, Axel; Borghouts, Corina; Delis, Natalia; Mack, Laura; Brill, Boris; Bernard, Anne-Charlotte; Coqueret, Olivier; Groner, Bernd

    2012-06-01

    Abstract Cytotoxic agents, alone or in combination, are being used in the treatment of colorectal cancer. Despite progress in the therapeutic regimes, this common malignancy is still the cause of considerable morbidity and mortality, and further improvements are required. Cancer cells often exhibit intrinsic resistance against chemotherapeutic agents or they develop resistance over the time of treatment. Several mechanisms have been made responsible, e.g., drugs may fail to reach tumor cells or drugs may fail to elicit cytotoxicity. The molecular characterization of drug resistance in cancer cells may lead to strategies to overcome it and enhance the sensitivity to chemotherapy. Irinotecan is one of the main treatments of colorectal cancer; it is converted into its active metabolite SN38 and acts as a topoisomerase I inhibitor. Inhibition of this enzyme prevents DNA relegation following uncoiling. Irinotecan has been used as a chemotherapeutic agent either as a single agent or in combination with 5-fluorouracil and targeted therapies directed against the epidermal growth factor receptor, such as cetuximab. The transcription factor signal transducer and activator of transcription 3 (Stat3) is a member of the signal transducer and activator of transcription protein family. Its persistent activation is found in tumor cells and has been associated with drug and radiation resistance. The treatment of colorectal cancer cells with irinotecan leads to senescence or apoptosis following DNA double-strand break induction. This process is impaired by the activation of Stat3. We have derived a Stat3 specific peptide aptamer [recombinant Stat3 inhibitory peptide aptamer (rS3-PA)] that recognizes the dimerization domain of Stat3 and effectively inhibits its function. The delivery of rS3-PA into colon cancer cells and the resulting inhibition of Stat3 strongly enhanced the cytotoxic action of SN38. These data show that the targeted inhibition of Stat3 decreases drug resistance and

  2. Mouse Skeletal Muscle Fiber-Type-Specific Macroautophagy and Muscle Wasting Are Regulated by a Fyn/STAT3/Vps34 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Eijiro Yamada

    2012-05-01

    Full Text Available Skeletal muscle atrophy induced by aging (sarcopenia, inactivity, and prolonged fasting states (starvation is predominantly restricted to glycolytic type II muscle fibers and typical spares oxidative type I fibers. However, the mechanisms accounting for muscle fiber-type specificity of atrophy have remained enigmatic. In the current study, although the Fyn tyrosine kinase activated the mTORC1 signaling complex, it also induced marked atrophy of glycolytic fibers with relatively less effect on oxidative muscle fibers. This was due to inhibition of macroautophagy via an mTORC1-independent but STAT3-dependent reduction in Vps34 protein levels and decreased Vps34/p150/Beclin1/Atg14 complex 1. Physiologically, in the fed state endogenous Fyn kinase activity was increased in glycolytic but not oxidative skeletal muscle. In parallel, Y705-STAT3 phosphorylation increased with decreased Vps34 protein levels. Moreover, fed/starved regulation of Y705-STAT3 phosphorylation and Vps34 protein levels was prevented in skeletal muscle of Fyn null mice. These data demonstrate a Fyn/STAT3/Vps34 pathway that is responsible for fiber-type-specific regulation of macroautophagy and skeletal muscle atrophy.

  3. The effect of STAT3 Inhibition on status epilepticus and subsequent spontaneous seizures in the Pilocarpine Model of Acquired Epilepsy

    OpenAIRE

    Grabenstatter, H. L.; Angel, Y. Cruz Del; Carlsen, J.; Wempe, M. F.; White, A. M.; Cogswell, M.; Russek, S. J.; BROOKS-KAYAL, A. R.

    2013-01-01

    Pilocarpine-induced status epilepticus (SE), which results in temporal lobe epilepsy (TLE) in rodents, activates the JAK/STAT pathway. In the current study, we evaluate whether brief exposure to a selective inhibitor of the JAK/STAT pathway (WP1066) early after the onset of SE effects the severity of SE or reduces later spontaneous seizure frequency via inhibition of STAT3-regulated gene transcription. Rats that received systemic WP1066 or vehicle at the onset of SE were continuously video-EE...

  4. Isoproterenol regulates CD44 expression in gastric cancer cells through STAT3/MicroRNA373 cascade.

    Science.gov (United States)

    Wei, Bo; Sun, Xiaoyan; Geng, Zhijun; Shi, Ming; Chen, Zhida; Chen, Lin; Wang, Yongan; Fu, Xiaobing

    2016-10-01

    Gastric cancer is a heterogeneous disease, and stem cells are thought to be the cell of origin contributed to this malignancy. However, studies with breast and intestinal cancer models show non-stem cancer cells can change their surface phenotype and convert into tumor-initiating cells induced by the signals emanating from surrounding tumor microenvironment. Here, we show that CD44 was expressed at different levels in gastric metastases compared with primary tumors, and also negatively correlated with the expression of miR-373. By using a panel of human gastric cancer cell lines and analysis of archived data from The Cancer Genomics Altas (TCGA) database, we verified the inverse correlation between CD44 and miR-373. Furthermore, the stress-associated hormone, isoproterenol, could increase the expression levels of "stem"-related proteins, such as CD44, Nanog, and Rex-1, and induce chemoresistance in gastric cancer cells. Transfection with miR-373, however, reversed not only the effect of isoproterenol on phenotypic conversion but also its effect on drug sensitivity. Isoproterenol triggered downstream target STAT3 mainly through β2-adrenergic receptors (β2-ARs). Activated STAT3 functioned as a miR-373 suppressor by binding to its promoter, which forms a positive feedback circuit to maintain CD44 activity and direct the phenotypic conversion from CD44(low) to CD44(hi) expression. Our data suggest an important role of β2-AR/STAT3/miR-373 signaling on the transformation of gastric cancer cells. This study also suggests a potential therapeutic or preventive treatment for gastric cancer patients who are especially prone to psychosocial stress. PMID:27512943

  5. EC-70124, a Novel Glycosylated Indolocarbazole Multikinase Inhibitor, Reverts Tumorigenic and Stem Cell Properties in Prostate Cancer by Inhibiting STAT3 and NF-κB.

    Science.gov (United States)

    Civenni, Gianluca; Longoni, Nicole; Costales, Paula; Dallavalle, Cecilia; García Inclán, Cristina; Albino, Domenico; Nuñez, Luz Elena; Morís, Francisco; Carbone, Giuseppina M; Catapano, Carlo V

    2016-05-01

    Cancer stem cells (CSC) contribute to disease progression and treatment failure in prostate cancer because of their intrinsic resistance to current therapies. The transcription factors NF-κB and STAT3 are frequently activated in advanced prostate cancer and sustain expansion of prostate CSCs. EC-70124 is a novel chimeric indolocarbazole compound generated by metabolic engineering of the biosynthetic pathways of glycosylated indolocarbazoles, such as staurosporine and rebeccamycin. In vitro kinome analyses revealed that EC-70124 acted as a multikinase inhibitor with potent activity against IKKβ and JAK2. In this study, we show that EC-70124 blocked concomitantly NF-κB and STAT3 in prostate cancer cells and particularly prostate CSCs, which exhibited overactivation of these transcription factors. Phosphorylation of IkB and STAT3 (Tyr705), the immediate targets of IKKβ and JAK2, respectively, was rapidly inhibited in vitro by EC-70124 at concentrations that were well below plasma levels in mice. Furthermore, the drug blocked activation of NF-κB and STAT3 reporters and suppressed transcription of their target genes. Treatment with EC-70124 impaired proliferation and colony formation in vitro and delayed development of prostate tumor xenografts. Notably, EC-70124 had profound effects on the prostate CSC subpopulation both in vitro and in vivo Thus, EC-70124 is a potent inhibitor of the NF-κB and STAT3 signaling pathways and blocked tumor growth and maintenance of prostate CSCs. EC-70124 may provide the basis for developing new therapeutic strategies that combine agents directed to the CSC component and the bulk tumor cell population for treatment of advanced prostate cancer. Mol Cancer Ther; 15(5); 806-18. ©2016 AACR. PMID:26826115

  6. Interleukin-32α inactivates JAK2/STAT3 signaling and reverses interleukin-6-induced epithelial-mesenchymal transition, invasion, and metastasis in pancreatic cancer cells.

    Science.gov (United States)

    Chen, Jingfeng; Wang, Silu; Su, Jiadong; Chu, Guanyu; You, Heyi; Chen, Zongjing; Sun, Hongwei; Chen, Bicheng; Zhou, Mengtao

    2016-01-01

    Interleukin (IL)-32 is a newly discovered cytokine that has multifaceted roles in inflammatory bowel disease, cancer, and autoimmune diseases and participates in cell apoptosis, cancer cell growth inhibition, accentuation of inflammation, and angiogenesis. Here, we investigated the potential effects of IL-32α on epithelial-mesenchymal transition, metastasis, and invasion, and the JAK2/STAT3 signaling pathway in pancreatic cancer cells. The human pancreatic cancer cell lines PANC-1 and SW1990 were used. Epithelial-mesenchymal transition-related markers, including E-cadherin, N-cadherin, Vimentin, Snail, and Zeb1, as well as extracellular matrix metalloproteinases (MMPs), including MMP2, MMP7, and MMP9, were detected by immunofluorescence, Western blotting, and real-time polymerase chain reaction. The activation of JAK2/STAT3 signaling proteins was detected by Western blotting. Wound healing assays, real-time polymerase chain reaction, and Western blotting were performed to assess cell migration and invasion. The effects of IL-32α on the IL-6-induced activation of JAK2/STAT3 were also evaluated. In vitro, we found that IL-32α inhibits the expressions of the related markers N-cadherin, Vimentin, Snail, and Zeb1, as well as JAK2/STAT3 proteins, in a dose-dependent manner in pancreatic cancer cell lines. Furthermore, E-cadherin expression was increased significantly after IL-32α treatment. IL-32α downregulated the expression of MMPs, including MMP2, MMP7, and MMP9, and decreased wound healing in pancreatic cancer cells. These consistent changes were also found in IL-6-induced pancreatic cancer cells following IL-32α treatment. This study showed that reversion of epithelial-mesenchymal transition, inhibition of invasiveness and metastasis, and activation of the JAK2/STAT3 signaling pathway could be achieved through the application of exogenous IL-32α. PMID:27471397

  7. Induction of murine macrophage M2 polarization by cigarette smoke extract via the JAK2/STAT3 pathway.

    Directory of Open Access Journals (Sweden)

    Fengjiao Yuan

    Full Text Available Cigarette smoking is a major pathogenic factor in lung cancer. Macrophages play an important role in host defense and adaptive immunity. These cells display diverse phenotypes for performing different functions. M2 type macrophages usually exhibit immunosuppressive and tumor-promoting characteristics. Although macrophage polarization toward the M2 phenotype has been observed in the lungs of cigarette smokers, the molecular basis of the process remains unclear. In this study, we evaluated the possible mechanisms for the polarization of mouse macrophages that are induced by cigarette smoking (CS or cigarette smoke extract (CSE. The results showed that exposure to CSE suppressed the production of reactive oxygen species (ROS and nitric oxide (NO and down-regulated the phagocytic ability of Ana-1 cells. The CD163 expressions on the surface of macrophages from different sources were significantly increased in in vivo and in vitro studies. The M1 macrophage cytokines TNF-α, IL-12p40 and enzyme iNOS decreased in the culture supernatant, and their mRNA levels decreased depending on the time and concentration of CSE. In contrast, the M2 phenotype macrophage cytokines IL-10, IL-6, TGF-β1 and TGF-β2 were up-regulated. Moreover, phosphorylation of JAK2 and STAT3 was observed after the Ana-1 cells were treated with CSE. In addition, pretreating the Ana-1 cells with the STAT3 phosphorylation inhibitor WP1066 inhibited the CSE-induced CD163 expression, increased the mRNA level of IL-10 and significantly decreased the mRNA level of IL-12. In conclusion, we demonstrated that the M2 polarization of macrophages induced by CS could be mediated through JAK2/STAT3 pathway activation.

  8. Sorafenib Enhances Radiation-Induced Apoptosis in Hepatocellular Carcinoma by Inhibiting STAT3

    International Nuclear Information System (INIS)

    Purpose: Hepatocellular carcinoma (HCC) is one of the most common and lethal human malignancies. Lack of efficient therapy for advanced HCC is a pressing problem worldwide. This study aimed to determine the efficacy and mechanism of combined sorafenib and radiation therapy treatment for HCC. Methods and Materials: HCC cell lines (PLC5, Huh-7, Sk-Hep1, and Hep3B) were treated with sorafenib, radiation, or both, and apoptosis and signal transduction were analyzed. Results: All 4 HCC cell lines showed resistance to radiation-induced apoptosis; however, this resistance could be reversed in the presence of sorafenib. Inhibition of phospho-STAT3 was found in cells treated with sorafenib or sorafenib plus radiation and subsequently reduced the expression levels of STAT3-related proteins, Mcl-1, cyclin D1, and survivin. Silencing STAT3 by RNA interference overcame apoptotic resistance to radiation in HCC cells, and the ectopic expression of STAT3 in HCC cells abolished the radiosensitizing effect of sorafenib. Moreover, sorafenib plus radiation significantly suppressed PLC5 xenograft tumor growth. Conclusions: These results indicate that sorafenib sensitizes resistant HCC cells to radiation-induced apoptosis via downregulating phosphorylation of STAT3 in vitro and in vivo

  9. Prediction and experimental validation of novel STAT3 target genes in human cancer cells.

    Directory of Open Access Journals (Sweden)

    Young Min Oh

    Full Text Available The comprehensive identification of functional transcription factor binding sites (TFBSs is an important step in understanding complex transcriptional regulatory networks. This study presents a motif-based comparative approach, STAT-Finder, for identifying functional DNA binding sites of STAT3 transcription factor. STAT-Finder combines STAT-Scanner, which was designed to predict functional STAT TFBSs with improved sensitivity, and a motif-based alignment to minimize false positive prediction rates. Using two reference sets containing promoter sequences of known STAT3 target genes, STAT-Finder identified functional STAT3 TFBSs with enhanced prediction efficiency and sensitivity relative to other conventional TFBS prediction tools. In addition, STAT-Finder identified novel STAT3 target genes among a group of genes that are over-expressed in human cancer cells. The binding of STAT3 to the predicted TFBSs was also experimentally confirmed through chromatin immunoprecipitation. Our proposed method provides a systematic approach to the prediction of functional TFBSs that can be applied to other TFs.

  10. Oncogenic kinase NPM/ALK induces through STAT3 expression of immunosuppressive protein CD274 (PD-L1, B7-H1).

    Science.gov (United States)

    Marzec, Michal; Zhang, Qian; Goradia, Ami; Raghunath, Puthiyaveettil N; Liu, Xiaobin; Paessler, Michele; Wang, Hong Yi; Wysocka, Maria; Cheng, Mangeng; Ruggeri, Bruce A; Wasik, Mariusz A

    2008-12-30

    The mechanisms of malignant cell transformation caused by the oncogenic, chimeric nucleophosmin (NPM)/anaplastic lymphoma kinase (ALK) remain only partially understood, with most of the previous studies focusing mainly on the impact of NPM/ALK on cell survival and proliferation. Here we report that the NPM/ALK-carrying T cell lymphoma (ALK+TCL) cells strongly express the immunosuppressive cell-surface protein CD274 (PD-L1, B7-H1), as determined on the mRNA and protein level. The CD274 expression is strictly dependent on the expression and enzymatic activity of NPM/ALK, as demonstrated by inhibition of the NPM/ALK function in ALK+TCL cells by the small molecule ALK inhibitor CEP-14083 and by documenting CD274 expression in IL-3-depleted BaF3 cells transfected with the wild-type NPM/ALK, but not the kinase-inactive NPM/ALK K210R mutant or empty vector alone. NPM/ALK induces CD274 expression by activating its key signal transmitter, transcription factor STAT3. STAT3 binds to the CD274 gene promoter in vitro and in vivo, as shown in the gel electromobility shift and chromatin immunoprecipitation assays, and is required for the PD-L1 gene expression, as demonstrated by siRNA-mediated STAT3 depletion. These findings identify an additional cell-transforming property of NPM/ALK and describe a direct link between an oncoprotein and an immunosuppressive cell-surface protein. These results also provide an additional rationale to therapeutically target NPM/ALK and STAT3 in ALK+TCL. Finally, they suggest that future immunotherapeutic protocols for this type of lymphoma may need to include the inhibition of NPM/ALK and STAT3 to achieve optimal clinical efficacy.

  11. Targeting colorectal cancer via its microenvironment by inhibiting IGF-1 Receptor-insulin receptor substrate and STAT3 signaling

    Science.gov (United States)

    Sanchez-Lopez, Elsa; Flashner-Abramson, Efrat; Shalapour, Shabnam; Zhong, Zhenyu; Taniguchi, Koji; Levitzki, Alexander; Karin, Michael

    2015-01-01

    The tumor microenvironment (TME) exerts critical pro-tumorigenic effects through cytokines and growth factors that support cancer cell proliferation, survival, motility and invasion. Insulin-like growth factor-1 (IGF-1) and Signal transducer and activator of transcription 3 (STAT3) stimulate colorectal cancer (CRC) development and progression via cell autonomous and microenvironmental effects. Using a unique inhibitor, NT157, which targets both IGF-1 receptor (IGF-1R) and STAT3, we show that these pathways regulate many TME functions associated with sporadic colonic tumorigenesis in CPC-APC mice, in which cancer development is driven by loss of the Apc tumor suppressor gene. NT157 causes a substantial reduction in tumor burden by affecting cancer cells, cancer-associated fibroblasts (CAF) and myeloid cells. Decreased cancer cell proliferation and increased apoptosis were accompanied by inhibition of CAF activation and decreased inflammation. Furthermore, NT157 inhibited expression of pro-tumorigenic cytokines, chemokines and growth factors, including IL-6, IL-11 and IL-23 as well as CCL2, CCL5, CXCL7, CXCL5, ICAM1 and TGFβ; decreased cancer cell migratory activity and reduced their proliferation in the liver. NT157 represents a new class of anti-cancer drugs that affect both the malignant cell and its supportive microenvironment. PMID:26364612

  12. The expression and significance of IL -6/STAT3 signaling pathway on the hypothalamus -pituitary-adrenal axis in the early stage of sepsis rats%IL -6/STAT3信号通路在脓毒症早期大鼠下丘脑-垂体-肾上腺轴中的表达及意义

    Institute of Scientific and Technical Information of China (English)

    王晓丹; 聂文龙; 张玉想

    2015-01-01

    Objective To explore the inner link between interleukin -6 ( IL -6 )/signal transducer and activator of transcription 3 ( STAT3 ) signaling pathway and hypothalamus -pituitary -adrenal axis ( HPAA) excessive activation in the early stage of sepsis rats .Methods Twenty -four adult male Wistar rats were randomly divided into Control group ( n=8 ) , sham-operated group ( n=8) and CLP group (n=8).The septic rat models were challenged by CLP , executed after 6 hours, the hypothalamus, pituitary and adrenal gland was isolated .Expression levels of CRH, IL-6, STAT3 and SOCS3 mRNA in hypothalamus , POMC, IL-6, STAT3 and SOCS3 mRNA in pituitary and IL -6, STAT3 and SOCS3 mRNA in adrenal gland were quantified by real -time quantitative PCR ( RT -PCR).Results Compared to Control group and Sham group: CRH, IL -6, STAT3 and SOCS3 mRNA expression levels were up -regulated significantly (P<0.01) in the hypothalamus tissues of CLP group;POMC, IL-6, STAT3 and SOCS3 mRNA expression levels were up -regulated significantly (P<0.01) in the pituitary tissues of CLP group; IL-6, STAT3 and SOCS3 mRNA expression levels were up-regulated significantly (P<0.01) in adrenal gland tissues of CLP group .Expression levels of all purpose gene were not different in Control group and Sham group .Conclusion IL -6/STAT3 signaling pathway has a close relationship with HPAA excessive activation in the early stage of sepsis rats.IL-6/STAT3 signaling pathway may be regarded as a novel therapeutic target for HPAA excessive activation of the sepsis .%目的:探讨大鼠脓毒症早期出现的HPA轴过度激活与IL-6/STAT3信号通路的内在联系。方法24只健康雄性Wistar大鼠,随机分为正常对照组( Control组)、假手术组( Sham组)、模型组(CLP组)三组。采用盲肠结扎穿孔(CLP)法建立脓毒症模型,术后6 h处死,分离出下丘脑、垂体、肾上腺组织。 RT-PCR检测下丘脑组织CRH、IL-6、STAT3、SOCS3 mRNA水平,垂体

  13. Concerted Suppression of STAT3 and GSK3β Is Involved in Growth Inhibition of Non-Small Cell Lung Cancer by Xanthatin

    OpenAIRE

    Li Tao; Fangtian Fan; Yuping Liu; Weidong Li; Lei Zhang; Junshan Ruan; Cunsi Shen; Xiaobo Sheng; Zhijie Zhu; Aiyun Wang; Wenxing Chen; Shile Huang; Yin Lu

    2013-01-01

    Xanthatin, a sesquiterpene lactone purified from Xanthium strumarium L., possesses prominent anticancer activity. We found that disruption of GSK3β activity was essential for xanthatin to exert its anticancer properties in non-small cell lung cancer (NSCLC), concurrent with preferable suppression of constitutive activation of STAT3. Interestingly, inactivation of the two signals are two mutually exclusive events in xanthatin-induced cell death. Moreover, we surprisingly found that exposure of...

  14. Hedyotis diffusa Willd Inhibits Colorectal Cancer Growth in Vivo via Inhibition of STAT3 Signaling Pathway

    OpenAIRE

    Jun Peng; Wei Xu; Aling Shen; Zhenfeng Hong; Jianwei Zeng; Youzhi Zhan; Ling Zhang; Lili Wang; Lihui Wei; Jiumao Lin; Qiaoyan Cai

    2012-01-01

    Signal Transducer and Activator of Transcription 3 (STAT3), a common oncogenic mediator, is constitutively activated in many types of human cancers; therefore it is a major focus in the development of novel anti-cancer agents. Hedyotis diffusa Willd has been used as a major component in several Chinese medicine formulas for the clinical treatment of colorectal cancer (CRC). However, the precise mechanism of its anti-tumor activity remains largely unclear. Using a CRC mous...

  15. Piperlongumine inhibits gastric cancer cells via suppression of the JAK1,2/STAT3 signaling pathway.

    Science.gov (United States)

    Song, Baoji; Zhan, Hongjie; Bian, Quan; Gu, Junping

    2016-05-01

    Piperlongumine (PL), a major active component of long peppers, has been reported to possess anti‑cancer properties; however, its effect on gastric cancer (GC) has remained to be demonstrated. The present study assessed the effects of PL on the MKN45 and AGS GC cell lines and explored the underlying mechanisms. An MTT assay revealed that PL suppressed the proliferation of GC cells, while flow cytometric analysis showed that PL inhibited cell cycle progression. Furthermore, Transwell assays revealed the inhibitory effects of PL on the invasion and migration of GC cells. In addition, PL reduced the phosphorylation of Janus kinase (JAK)1, JAK2 and signal transducer and activator of transcription (STAT)3 in a concentration‑dependent manner, as indicated by western blot analysis, and decreased the expression of STAT3‑dependent tumor‑associated genes in GC cells, as revealed by PCR analysis. In conclusion, the present study was the first, to the best of our knowledge, to reveal the efficacy of PL against GC. The consumption of long peppers is therefore recommended for the prevention and treatment of GC, and PL may be a promising candidate drug for treating GC. PMID:27053336

  16. STAT3,pSTAT3与TFF3在甲状腺乳头状癌中的临床意义%Clinical significance of STAT3, pSTAT3 and TFF3 in human papillary thyroid carcinoma

    Institute of Scientific and Technical Information of China (English)

    张晨蕾; 李燕萍; 吴靖芳; 万佳鑫; 陈亚敏; 张文静; 薛刚

    2016-01-01

    目的 探讨甲状腺乳头状癌(Papillary Thyroid Carcinomas,PTC) STAT3及其磷酸化水平与三叶因子3(Trefoil Factor 3,TFF3)表达及相关性.方法 采用免疫组织化学检测31例组织芯片中PTC及癌旁组织STAT3、pSTAT3和TFF3阳性率与平均光密度(AOD)值;Western Blot检测6例PTC和癌旁手术标本中相应蛋白的含量,并进行相关分析.结果 (1)免疫组化:TFF3蛋白在PTC中均高表达(P<0.001),TFF3阳性率与AOD值在直径>2 cm组、淋巴结转移组和临床Ⅲ~Ⅳ病例明显高于直径≤2 cm组、无淋巴结转移组和Ⅰ~Ⅱ期者(x2=12.120,P=0.001,x2=7.517,P=0.043,x2=10.490, P=0.003;AOD值:t=2.810, P=0.0064, t=2.234, P=0.039, t=2.926, P=0.0058);PTC中STAT3阳性率和AOD值与临床资料无关.pSTAT3为胞核阳性,阳性率和AOD值在PTC组织低于癌旁组织,直径>2 cm组、淋巴结转移组和临床Ⅲ~Ⅳ病例明显低于直径≤2 cm组、无淋巴结转移组和Ⅰ~Ⅱ期者(x2=4.963, P=0.046,x2=4.882, P=0.033;AOD值:t=2.195, P=0.041, t=2.790, P=0.0068, t=2.018, P=0.042);TFF3与STAT3呈正相关,与pSTAT3呈负相关(P<0.01). (2) Westem Blot: TFF3和STAT3蛋白在PTC的表达高于癌旁组织(t=2.841,P=0.008,t=2.925,P=0.007),但pSTAT3却明显低于癌旁组织(t=2.713,P=0.009).结论 甲状腺乳头状癌TFF3和STAT3高表达、pSTAT3低表达对PTC不良预后的预测有指导意义.

  17. IGFBP2 potentiates nuclear EGFR-STAT3 signaling

    OpenAIRE

    Chua, Corrine Yingxuan; Liu, Yuexin; Granberg, Kirsi J.; Hu, Limei; Haapasalo, Hannu; Annala, Matti J.; Cogdell, David E.; Verploegen, Maartje; Moore, Lynette M.; Fuller, Gregory N.; Nykter, Matti; Cavenee, Webster K.; Zhang, Wei

    2015-01-01

    Insulin-like growth factor binding protein 2 (IGFBP2) is a pleiotropic oncogenic protein that has both extracellular and intracellular functions. Despite a clear causal role in cancer development, the tumor-promoting mechanisms of IGFBP2 are poorly understood. The contributions of intracellular IGFBP2 to tumor development and progression are also unclear. Here we present evidence that both exogenous IGFBP2 treatment and cellular IGFBP2 overexpression lead to aberrant activation of EGFR, which...

  18. Mycoplasma pneumoniae modulates STAT3-STAT6/EGFR-FOXA2 signaling to induce overexpression of airway mucins.

    Science.gov (United States)

    Hao, Yonghua; Kuang, Zhizhou; Jing, Jia; Miao, Jinfeng; Mei, Li Yu; Lee, Ryan J; Kim, Susie; Choe, Shawn; Krause, Duncan C; Lau, Gee W

    2014-12-01

    Aberrant mucin secretion and accumulation in the airway lumen are clinical hallmarks associated with various lung diseases such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis. Mycoplasma pneumoniae, long appreciated as one of the triggers of acute exacerbations of chronic pulmonary diseases, has recently been reported to promote excessive mucus secretion. However, the mechanism of mucin overproduction induced by M. pneumoniae remains unclear. This study aimed to determine the mechanism by which M. pneumoniae induces mucus hypersecretion by using M. pneumoniae infection of mouse lungs, human primary bronchial epithelial (NHBE) cells cultured at the air-liquid interface, and the conventionally cultured airway epithelial NCI-H292 cell line. We demonstrated that M. pneumoniae induced the expression of mucins MUC5AC and MUC5B by activating the STAT6-STAT3 and epidermal growth factor receptor (EGFR) signal pathways, which in turn downregulated FOXA2, a transcriptional repressor of mucin biosynthesis. The upstream stimuli of these pathways, including interleukin-4 (IL-4), IL-6, and IL-13, increased dramatically upon exposure to M. pneumoniae. Inhibition of the STAT6, STAT3, and EGFR signaling pathways significantly restored the expression of FOXA2 and attenuated the expression of airway mucins MUC5AC and MUC5B. Collectively, these studies demonstrated that M. pneumoniae induces airway mucus hypersecretion by modulating the STAT/EGFR-FOXA2 signaling pathways. PMID:25287927

  19. Chidamide, a novel histone deacetylase inhibitor, inhibits the viability of MDS and AML cells by suppressing JAK2/STAT3 signaling

    Science.gov (United States)

    Zhao, Sida; Guo, Juan; Zhao, Youshan; Fei, Chengming; Zheng, Qingqing; Li, Xiao; Chang, Chunkang

    2016-01-01

    Many studies have indicated that histone deacetylase (HDAC) activity is always increased in a lot of human tumors, and inhibition of HDAC activity is a promising new strategy in the treatment of cancers. Chidamide, a novel HDAC inhibitor of the benzamide class, is currently under clinical trials. In this study, we aimed to investigate the antitumor activity of Chidamide on myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) cell lines and explore the possible mechanism. Chidamide exhibited efficient anti-proliferative activity on MDS and AML cells in a time- and dose-dependent manner, accompanied by cell cycle arrest at G0/G1 phase and cell apoptosis. Importantly, Chidamide possessed potent HDAC inhibition property, as evaluated by HDAC activity analysis and acetylation of histone H3 and H4. Moreover, Chidamide significantly increased the expression of Suppressors of cytokine signaling 3 (SOCS3), reduced the expression of Janus activated kinases 2 (JAK2) and Signal transducer and activator of transcription 3 (STAT3), and inhibited STAT3 downstream genes, including c-Myc, Bcl-xL, and Mcl-1, which are involved in cell cycle progression and anti-apoptosis. Therefore, we demonstrate that Chidamide exhibits potent inhibitory effect on cell viability of MDS and AML cells, and the possible mechanism may lie in the downregulation of JAK2/STAT3 signaling through SOCS3 upregulation. Our data provide rationale for clinical investigations of Chidamide in MDS and AML. PMID:27508038

  20. IL-6 Trans-signaling-STAT3 Pathway Mediates ECM and Cellular Proliferation in Fibroblasts from Hypertrophic Scar

    OpenAIRE

    Ray, Sutapa; Ju, Xiaoxi; Sun, Hong; Finnerty, Celeste C.; Herndon, David N; Allan R Brasier

    2013-01-01

    The molecular mechanisms behind the pathogenesis of post-burn hypertrophic scar (HS) remain unclear. Here, we investigate the role of interleukin-6 (IL-6) trans-signaling-STAT3 pathway in HS fibroblasts (HSF) derived from burned-induced HS skin. HSF showed increased Tyr 705 STAT3 phosphorylation over normal fibroblast (NF) after IL-6•IL-6Rα stimulation by immunoassays. The endogenous STAT3 target gene, SOCS3, was upregulated in HSF and showed increased STAT3 binding on its promoter relative t...

  1. IL-6 Trans-signaling-STAT3 Pathway Mediates ECM and Cellular Proliferation in Fibroblasts from Hypertrophic Scar

    Science.gov (United States)

    Ray, Sutapa; Ju, Xiaoxi; Sun, Hong; Finnerty, Celeste C; Herndon, David N; Brasier, Allan R

    2012-01-01

    The molecular mechanisms behind the pathogenesis of post-burn hypertrophic scar (HS) remain unclear. Here, we investigate the role of interleukin-6 (IL-6) trans-signaling-STAT3 pathway in HS fibroblasts (HSF) derived from burned-induced HS skin. HSF showed increased Tyr 705 STAT3 phosphorylation over normal fibroblast (NF) after IL-6•IL-6Rα stimulation by immunoassays. The endogenous STAT3 target gene, SOCS3, was upregulated in HSF and showed increased STAT3 binding on its promoter relative to NF in Chromatin Immunoprecipitation assay. We observed that the cell surface signaling transducer glycoprotein 130 is upregulated in HSF using Q-RT-PCR and flow cytometry. The production of excessive extracellular matrix (ECM), including the expression of alpha2 (1) procollagen (Col1A2) and fibronectin 1 (FN) were seen in HSFs. A STAT3 peptide inhibitor abrogated FN and Col1A2 gene expression in HSF indicating involvement of STAT3 in ECM production. The cellular proliferation markers Cyclin D1, Bcl-Xl and c-Myc were also upregulated in HSF and knockdown of STAT3 by siRNA attenuated c-Myc expression indicating the essential role of STAT3 in fibroblast proliferation. Taken together, our results suggest that the IL-6-trans-signaling-STAT3 pathway may play an integral role in HS pathogenesis and disruption of this pathway could be a potential therapeutic strategy for the treatment of burn-induced HS. PMID:23303450

  2. Concerted suppression of STAT3 and GSK3β is involved in growth inhibition of non-small cell lung cancer by Xanthatin.

    Directory of Open Access Journals (Sweden)

    Li Tao

    Full Text Available Xanthatin, a sesquiterpene lactone purified from Xanthium strumarium L., possesses prominent anticancer activity. We found that disruption of GSK3β activity was essential for xanthatin to exert its anticancer properties in non-small cell lung cancer (NSCLC, concurrent with preferable suppression of constitutive activation of STAT3. Interestingly, inactivation of the two signals are two mutually exclusive events in xanthatin-induced cell death. Moreover, we surprisingly found that exposure of xanthatin failed to trigger the presumable side effect of canonical Wnt/β-Catenin followed by GSK3β inactivation. We further observed that the downregulation of STAT3 was required for xanthatin to fine-tune the risk. Thus, the discovery of xanthatin, which has ability to simultaneously orchestrate two independent signaling cascades, may have important implications for screening promising drugs in cancer therapies.

  3. Concerted suppression of STAT3 and GSK3β is involved in growth inhibition of non-small cell lung cancer by Xanthatin.

    Science.gov (United States)

    Tao, Li; Fan, Fangtian; Liu, Yuping; Li, Weidong; Zhang, Lei; Ruan, Junshan; Shen, Cunsi; Sheng, Xiaobo; Zhu, Zhijie; Wang, Aiyun; Chen, Wenxing; Huang, Shile; Lu, Yin

    2013-01-01

    Xanthatin, a sesquiterpene lactone purified from Xanthium strumarium L., possesses prominent anticancer activity. We found that disruption of GSK3β activity was essential for xanthatin to exert its anticancer properties in non-small cell lung cancer (NSCLC), concurrent with preferable suppression of constitutive activation of STAT3. Interestingly, inactivation of the two signals are two mutually exclusive events in xanthatin-induced cell death. Moreover, we surprisingly found that exposure of xanthatin failed to trigger the presumable side effect of canonical Wnt/β-Catenin followed by GSK3β inactivation. We further observed that the downregulation of STAT3 was required for xanthatin to fine-tune the risk. Thus, the discovery of xanthatin, which has ability to simultaneously orchestrate two independent signaling cascades, may have important implications for screening promising drugs in cancer therapies. PMID:24312384

  4. Study on the correlation between EGFR-STAT3 signal pathwayand laryngeal papilloma%上皮生长因子受体-信号转导与转录激活因子3信号转导通路与喉乳头状瘤的相关性研究

    Institute of Scientific and Technical Information of China (English)

    王新华; 孙敬武

    2009-01-01

    Objective:To explore the relationship between the expression of EGFR and STAT3 in human la-ryngeal papilloma and its biological behavior. Method: Reverse transcription polymerasechain reaction(RT-PCR), immunohistochemical staining and Western blot were used to evaluate the mRNA and protein expression of EGFR and STAT3(p-STAT3) in 42 laryngeal papilloma tissues and 15 samples of normal laryngeal tissue, and the rela-tionship between the protein expression of them and clinicpathological parameters was also analysized. Result: The mRNA expression levels of EGFR and STAT3 in laryngeal papilloma tissue were significantly higher than that in normal laryngeal tissue(P<0.05,P<0.01). Protein positive expression of EGFR and p-STAT3 were also detected in a significantly greater proportion of laryngeal papilloma than normal laryngeal tissue by immunohistochemistry and western blot(P<0.01,P<0.05). There was relationship between EGFR and p-STAT3 overexpression in la-ryngeal papilloma(P<0.05). The expression p-STAT3 was correlated with the recurrence and canceration of la-ryngeal papilloma(P<0.05). Conclusion: The EGFR-STAT3 signal transduction pathway may be involved in the pathogenesis of laryngeal papilloma,, and the persistent activation of STAT3 gene plays an important role in the recurrence and canceration of laryngeal papilloma.%目的:探讨喉乳头状瘤中上皮生长因子受体(EGFR)和信号转导与转录激活因子3(STAT3) 的表达与其生物学行为的关系.方法:采用RT-PCR、免疫组织化学方法和Western blot,检测42例喉乳头状瘤和15例正常喉黏膜组织中EGFR和STAT3、磷酸化-STAT3(p-STAT3)的mRNA和蛋白质表达情况, 同时将蛋白质表达水平与喉乳头状瘤的临床病理参数进行相关性分析.结果:EGFR与STAT3的mRNA在喉乳头状瘤组织表达水平显著高于正常喉组织(P<0.05,P<0.01).免疫组织化学及Western blot方法也证实喉乳头状瘤组织中EGFR与STAT3 (p-STAT3)的蛋白质表达水

  5. STAT1, STAT3 and p38MAPK are involved in the apoptotic effect induced by a chimeric cyclic interferon-{alpha}2b peptide

    Energy Technology Data Exchange (ETDEWEB)

    Blank, Viviana C.; Pena, Clara [Institute of Biochemistry and Biophysics (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Junin 956-C1113AAD Buenos Aires (Argentina); Roguin, Leonor P., E-mail: rvroguin@qb.ffyb.uba.ar [Institute of Biochemistry and Biophysics (UBA-CONICET), School of Pharmacy and Biochemistry, University of Buenos Aires, Junin 956-C1113AAD Buenos Aires (Argentina)

    2010-02-15

    In the search of mimetic peptides of the interferon-{alpha}2b molecule (IFN-{alpha}2b), we have previously designed and synthesized a chimeric cyclic peptide of the IFN-{alpha}2b that inhibits WISH cell proliferation by inducing an apoptotic response. Here, we first studied the ability of this peptide to activate intracellular signaling pathways and then evaluated the participation of some signals in the induction of apoptosis. Stimulation of WISH cells with the cyclic peptide showed tyrosine phosphorylation of Jak1 and Tyk2 kinases, tyrosine and serine phosphorylation of STAT1 and STAT3 transcription factors and activation of p38 MAPK pathway, although phosphorylation levels or kinetics were in some conditions different to those obtained under IFN-{alpha}2b stimulus. JNK and p44/42 pathways were not activated by the peptide in WISH cells. We also showed that STAT1 and STAT3 downregulation by RNA interference decreased the antiproliferative activity and the amount of apoptotic cells induced by the peptide. Pharmacological inhibition of p38 MAPK also reduced the peptide growth inhibitory activity and the apoptotic effect. Thus, we demonstrated that the cyclic peptide regulates WISH cell proliferation through the activation of Jak/STAT signaling pathway. In addition, our results indicate that p38 MAPK may also be involved in cell growth regulation. This study suggests that STAT1, STAT3 and p38 MAPK would be mediating the antitumor and apoptotic response triggered by the cyclic peptide in WISH cells.

  6. Skin microbiome imbalance in patients with STAT1/STAT3 defects impairs innate host defense responses

    NARCIS (Netherlands)

    Smeekens, S.P.; Huttenhower, C.; Riza, A.L.; Veerdonk, F.L. van de; Zeeuwen, P.L.J.M.; Schalkwijk, J.; Meer, J.W.M. van der; Xavier, R.J.; Netea, M.G.; Gevers, D.

    2014-01-01

    BACKGROUND: Chronic mucocutaneous candidiasis (CMC) and hyper-IgE syndrome (HIES) are primary immunodeficiencies mainly caused by mutations in STAT1 and STAT3, respectively. CMC and HIES patients have an increased risk for skin and mucosal infections with fungal pathogens and Staphylococcus aureus.

  7. Identification of a novel STAT3 mutation in a patient with hyper-IgE syndrome

    DEFF Research Database (Denmark)

    Mogensen, Trine H; Jakobsen, Marianne; Larsen, Carsten S

    2013-01-01

    Here we describe a patient with hyper-IgE syndrome presenting with recurrent staphylococcal abscesses, pneumonia, and chronic mucocutaneous candidiasis, and report the identification of a novel STAT3 mutation at amino acid position 621, which has not previously been described. In addition, we...

  8. Correlation between endometriosis combined with infertility and STAT3 gene polymorphisms

    Institute of Scientific and Technical Information of China (English)

    Juan Hu; Feng Ye

    2016-01-01

    Objective:To investigate the correlation between STAT3 gene polymorphisms and endometriosis complicated with infertility.Methods: A total of 35 patients with endometriosis complicated with infertility and 35 cases of healthy volunteer from October 2014 to October 2015 in our hospital were selected as research objects. STAT3 gene polymorphisms of all objects were detected by PCR-RFLP method.Results: Polymorphic sites of STAT3 gene rs2293152 were expressed as three genotypes, namely, CC, GC, and GG. There were 18 cases, 10 cases and 7 cases of type CC, GC and GG in the observation group, accounted for 51.43%, 28.57% and 20.00%, respectively. There were 29 cases, 3 cases and 3 cases of type CC, GC and GG in the control group, accounted for 82.86%, 8.57% and 8.57%. There was a statistically difference` between the two groups. The frequency of C and G allele in the observation group and the control group were 65.71%, 34.29% and 87.14%, 12.86%, respectively. There were statistically significant differences between two groups. In addition, compared with the CC genotype, genotype G might increase the risk of the disease.Conclusions:The susceptibility of endometriosis complicated with infertility may be associated with STAT3 gene polymorphism and women who carried the G allele may have an increased the risk of the disease.

  9. Common STAT3 variants are not associated with obesity or insulin resistance in female twins

    NARCIS (Netherlands)

    Jamshidi, Yalda; Kyriakou, Theodosios; Gooljar, Sakina B.; Collins, Laura J.; Lane, Carl A.; Snieder, Harold; Wang, Xiaoling; Spector, Tim D.; O'Dell, Sandra D.

    2007-01-01

    JAMSHIDI, YALDA, THEODOSIOS KYRIAKOU, SAKINA B. GOOLJAR, LAURA J. COLLINS, CARL A. LANE, HAROLD SNIEDER, XIAOLING WANG, TIM D. SPECTOR, AND SANDRA D. O'DELL. Common STAT3 variants are not associated with obesity or insulin resistance in female twins. Obesity. 2007; 15:1634-1639. In animal models, ST

  10. STAT3, a Key Parameter of Cytokine-driven Tissue Protection During Sterile Inflammation – the Case of Experimental Acetaminophen (Paracetamol-induced Liver Damage

    Directory of Open Access Journals (Sweden)

    Heiko eMühl

    2016-05-01

    Full Text Available Acetaminophen (APAP, N-acetyl-p-aminophenol, or paracetamol overdosing is a prevalent cause of acute liver injury. While clinical disease is initiated by overt parenchymal hepatocyte necrosis in response to the analgetic, course of intoxication is substantially influenced by associated activation of innate immunity. This process is supposed to be set in motion by release of danger associated molecular patterns (DAMPs from dying hepatocytes and is accompanied by an inflammatory cytokine response. Murine models of APAP-induced liver injury emphasize the complex role that DAMPs and cytokines play in promoting either hepatic pathogenesis or resolution and recovery from intoxication. Whereas the function of key inflammatory cytokines is controversially discussed, a subclass of specific cytokines capable of efficiently activating the hepatocyte signal transducer and activator of transcription (STAT-3 pathway stands out as being consistently protective in murine models of APAP intoxication. Those include foremost interleukin (IL-6, IL-11, IL-13, and IL-22. Above all, activation of STAT3 under the influence of these cytokines has the capability to drive hepatocyte compensatory proliferation, a key principle of the regenerating liver. Herein, the role of these specific cytokines during experimental APAP-induced liver injury is highlighted and discussed in a broader perspective. In hard-to-treat or at-risk patients standard therapy may fail and APAP intoxication can proceed towards a fatal condition. Focused administration of recombinant STAT3-activating cytokines may evolve as novel therapeutic approach under those ill-fated conditions.

  11. The Inflammatory Transcription Factors NFκB, STAT1 and STAT3 Drive Age-Associated Transcriptional Changes in the Human Kidney.

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    Zach K O'Brown

    2015-12-01

    Full Text Available Human kidney function declines with age, accompanied by stereotyped changes in gene expression and histopathology, but the mechanisms underlying these changes are largely unknown. To identify potential regulators of kidney aging, we compared age-associated transcriptional changes in the human kidney with genome-wide maps of transcription factor occupancy from ChIP-seq datasets in human cells. The strongest candidates were the inflammation-associated transcription factors NFκB, STAT1 and STAT3, the activities of which increase with age in epithelial compartments of the renal cortex. Stimulation of renal tubular epithelial cells with the inflammatory cytokines IL-6 (a STAT3 activator, IFNγ (a STAT1 activator, or TNFα (an NFκB activator recapitulated age-associated gene expression changes. We show that common DNA variants in RELA and NFKB1, the two genes encoding subunits of the NFκB transcription factor, associate with kidney function and chronic kidney disease in gene association studies, providing the first evidence that genetic variation in NFκB contributes to renal aging phenotypes. Our results suggest that NFκB, STAT1 and STAT3 underlie transcriptional changes and chronic inflammation in the aging human kidney.

  12. Elevated STAT3 Signaling-Mediated Upregulation of MMP-2/9 Confers Enhanced Invasion Ability in Multidrug-Resistant Breast Cancer Cells

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    Fei Zhang

    2015-10-01

    Full Text Available The development of multidrug resistance greatly impedes effective cancer therapy. Recent advances in cancer research have demonstrated that acquisition of multidrug resistance by cancer cells is usually accompanied by enhanced cell invasiveness. Several lines of evidence indicated that cross activation of other signaling pathways during development of drug resistance may increase invasive potential of multidrug-resistant (MDR cancer cells. However, the accurate mechanism of this process is largely undefined. In this study, to better understand the associated molecular pathways responsible for cancer progression induced by drug resistance, a MDR human breast cancer cell line SK-BR-3/EPR with P-glycoprotein overexpression was established using stepwise long-term exposure to increasing concentration of epirubicin. The SK-BR-3/EPR cell line exhibited decreased cell proliferative activity, but enhanced cell invasive capacity. We showed that the expression of metastasis-related matrix metalloproteinase (MMP-2/9 was elevated in SK-BR-3/EPR cells. Moreover, SK-BR-3/EPR cells showed elevated activation of STAT3. Activation of STAT3 signaling is responsible for enhanced invasiveness of SK-BR-3/EPR cells through upregulation of MMP-2/9. STAT3 is a well-known oncogene and is frequently implicated in tumorigenesis and chemotherapeutic resistance. Our findings augment insight into the mechanism underlying the functional association between MDR and cancer invasiveness.

  13. The Inflammatory Transcription Factors NFκB, STAT1 and STAT3 Drive Age-Associated Transcriptional Changes in the Human Kidney.

    Science.gov (United States)

    O'Brown, Zach K; Van Nostrand, Eric L; Higgins, John P; Kim, Stuart K

    2015-12-01

    Human kidney function declines with age, accompanied by stereotyped changes in gene expression and histopathology, but the mechanisms underlying these changes are largely unknown. To identify potential regulators of kidney aging, we compared age-associated transcriptional changes in the human kidney with genome-wide maps of transcription factor occupancy from ChIP-seq datasets in human cells. The strongest candidates were the inflammation-associated transcription factors NFκB, STAT1 and STAT3, the activities of which increase with age in epithelial compartments of the renal cortex. Stimulation of renal tubular epithelial cells with the inflammatory cytokines IL-6 (a STAT3 activator), IFNγ (a STAT1 activator), or TNFα (an NFκB activator) recapitulated age-associated gene expression changes. We show that common DNA variants in RELA and NFKB1, the two genes encoding subunits of the NFκB transcription factor, associate with kidney function and chronic kidney disease in gene association studies, providing the first evidence that genetic variation in NFκB contributes to renal aging phenotypes. Our results suggest that NFκB, STAT1 and STAT3 underlie transcriptional changes and chronic inflammation in the aging human kidney.

  14. Roles of STAT3/SOCS3 Pathway in Regulating the Visual Function and Ubiquitin-Proteasome-dependent Degradation of Rhodopsin during Retinal Inflammation*

    OpenAIRE

    Ozawa, Yoko; Nakao, Keiko; Kurihara, Toshihide; Shimazaki, Takuya; Shimmura, Shigeto; Ishida, Susumu; Yoshimura, Akihiko; Tsubota, Kazuo; Okano, Hideyuki

    2008-01-01

    Inflammatory cytokines cause tissue dysfunction. We previously reported that retinal inflammation down-regulates rhodopsin expression and impairs visual function by an unknown mechanism. Here, we demonstrate that rhodopsin levels were preserved by suppressor of cytokine signaling 3 (SOCS3), a negative feedback regulator of STAT3 activation. SOCS3 was expressed mainly in photoreceptor cells in the retina. In the SOCS3-deficient retinas, rhodopsin protein levels dropped sooner, and the reductio...

  15. Inhibition of STAT3, FAK and Src mediated signaling reduces cancer stem cell load, tumorigenic potential and metastasis in breast cancer

    OpenAIRE

    Thakur, Ravi; Trivedi, Rachana; Rastogi, Namrata; Singh, Manisha; Mishra, Durga Prasad

    2015-01-01

    Cancer stem cells (CSCs) are responsible for aggressive tumor growth, metastasis and therapy resistance. In this study, we evaluated the effects of Shikonin (Shk) on breast cancer and found its anti-CSC potential. Shk treatment decreased the expression of various epithelial to mesenchymal transition (EMT) and CSC associated markers. Kinase profiling array and western blot analysis indicated that Shk inhibits STAT3, FAK and Src activation. Inhibition of these signaling proteins using standard ...

  16. Oncostatin-M Differentially Regulates Mesenchymal and Proneural Signature Genes in Gliomas via STAT3 Signaling

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    Kumar Natesh

    2015-02-01

    Full Text Available Glioblastoma (GBM, the most malignant of the brain tumors is classified on the basis of molecular signature genes using TCGA data into four subtypes- classical, mesenchymal, proneural and neural. The mesenchymal phenotype is associated with greater aggressiveness and low survival in contrast to GBMs enriched with proneural genes. The proinflammatory cytokines secreted in the microenvironment of gliomas play a key role in tumor progression. The study focused on the role of Oncostatin-M (OSM, an IL-6 family cytokine in inducing mesenchymal properties in GBM. Analysis of TCGA and REMBRANDT data revealed that expression of OSMR but not IL-6R or LIFR is upregulated in GBM and has negative correlation with survival. Amongst the GBM subtypes, OSMR level was in the order of mesenchymal > classical > neural > proneural. TCGA data and RT-PCR analysis in primary cultures of low and high grade gliomas showed a positive correlation between OSMR and mesenchymal signature genes-YKL40/CHI3L1, fibronectin and vimentin and a negative correlation with proneural signature genes-DLL3, Olig2 and BCAN. OSM enhanced transcript and protein level of fibronectin and YKL-40 and reduced the expression of Olig2 and DLL3 in GBM cells. OSM-regulated mesenchymal phenotype was associated with enhanced MMP-9 activity, increased cell migration and invasion. Importantly, OSM induced mesenchymal markers and reduced proneural genes even in primary cultures of grade-III glioma cells. We conclude that OSM-mediated signaling contributes to aggressive nature associated with mesenchymal features via STAT3 signaling in glioma cells. The data suggest that OSMR can be explored as potential target for therapeutic intervention.

  17. Diet-derived polyphenols inhibit angiogenesis by modulating the interleukin-6/STAT3 pathway

    Energy Technology Data Exchange (ETDEWEB)

    Lamy, Sylvie; Akla, Naoufal; Ouanouki, Amira; Lord-Dufour, Simon; Beliveau, Richard, E-mail: oncomol@nobel.si.uqam.ca

    2012-08-01

    Several epidemiological studies have indicated that abundant consumption of foods from plant origin is associated with a reduced risk of developing several types of cancers. This chemopreventive effect is related to the high content of these foods in phytochemicals, such as polyphenols, that interfere with several processes involved in cancer progression including tumor cell growth, survival and angiogenesis. In addition to the low intake of plant-based foods, increased body mass and physical inactivity have recently emerged as other important lifestyle factors influencing cancer risk, leading to the generation of low-grade chronic inflammatory conditions which are a key process involved in tumor progression. The objectives of the current study are to investigate the inhibitory effects of these polyphenols on angiogenesis triggered by an inflammatory cytokine (IL-6) and to determine the mechanisms underlying this action. We found that, among the tested polyphenols, apigenin and luteolin were the most potent angiogenesis inhibitors through their inhibitory effect on the inflammatory cytokine IL-6/STAT3 pathway. These effects resulted in modulation of the activation of extracellular signal-regulated kinase-1/2 signaling triggered by IL-6, as well as in a marked reduction in the proliferation, migration and morphogenic differentiation of endothelial cells. Interestingly, these polyphenols also modulated the expression of IL-6 signal transducing receptor (IL-6R{alpha}) and the secretion of the extracellular matrix degrading enzyme MMP-2 as well as the expression of suppressor of cytokine signaling (SOCS3) protein. Overall, these results may provide important new information on the role of diet in cancer prevention.

  18. STAT3 Silencing Inhibits Migration of Murine Breast Cancer Cells in vitro%STAT3基因沉默降低小鼠乳腺癌细胞的体外迁移能力

    Institute of Scientific and Technical Information of China (English)

    徐良; 顾玉超; 时瀚; 宓文义; 于文功

    2010-01-01

    信号转导子与转录活化子3(STAT3)是一个具有信号转导和转录调控双重功能的转录因子,有文献报道STAT3在乳腺癌中的表达显著升高,并能促进乳腺癌的转移.为了深入探索STAT3在肿瘤发生发展中的作用和影响乳腺癌转移的分子机制,采用RNA干扰技术在小鼠乳腺癌细胞株4T1中沉默STAT3的表达.MTT实验结果显示STAT3沉默对4T1细胞的增殖能力没有影响;细胞迁移实验结果表明STAT3表达被沉默后4T1细胞的迁移能力明显被抑制;定量PCR结果显示,STAT3基因沉默后4T1细胞中VEGF和IL-6的mRNA水平下降,E-cadherin表达上升,mosin表达下降;信号通路检测显示STAT3基因表达沉默后MAPK的活化明显降低.研究表明STAT3在小鼠乳腺癌细胞的迁移过程中发挥重要作用,为以STAT3基因为靶向的治疗提供了一定的实验依据.

  19. Jak1/STAT3 pathway mediates the inhibition of lipoxin A4 on TNF-α-induced DNA synthesis of glomerular mesangial cells in rats

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Objective: To examine whether lipoxin A4 (LXA4) has an inhibitory effect on tumor necrosis factor-α(TNF-α)-induced DNA synthesis of glomerular mesangial cells of rat, and explore the molecular mechanisms of LXA4 action. Methods: Glomerular mesangial cells of rat were cultured and preincubated with LXA4 at different concentrations, and then treated with TNF-α( 10 ng/ml). DNA synthesis was assessed by the incorporation of [3H]-thymidine in mesangial cells. Expression of cyclin E protein was determined by Western blotting analysis. Activities of signal transducers and activators of transcription-3 (STAT3) were analyzed by electrophoretic mobility shift assay (EMSA). Results: TNF-α-stimulated DNA synthesis of mesangial cells, upregulation of cyclin E protein and STAT3 activities were inhibited by LXA4 in a dose-dependent manner. Conclusion: TNF-α-induced DNA synthesis of mesangial cells can be inhibited by TXA4probably through the mechanism of Jak1/STAT3 pathway-dependent signal transduction.

  20. High nuclear expression of STAT3 is associated with unfavorable prognosis in diffuse large B-cell lymphoma

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    Zhu J

    2011-08-01

    Full Text Available Abstract Background The purpose of the study was to investigate the expression and prognostic value of STAT3 in diffuse large B-cell lymphoma (DLBCL. Methods Seventy-four DLBCL patients from 2001 to 2007 were reviewed in the study. The STAT3 expression in their tumor tissues was examined using the immunohistochemistry (IHC method, and evaluated for its association with clinicopathological parameters. Results Strong nuclear staining of STAT3 and phosphorylated-STAT3tyr705 (P-STAT3 were observed in 19 cases (25.7% and 24 cases (32.4%, respectively, and the expression levels were highly consistent between them (P = 0.001. The high nuclear expression of STAT3 was more frequent in the non-germinal center B cell-like (non-GCB DLBCL than that in the GCB subtype, but not reaching significance (P P = 0.005. Multivariate Cox regression analysis showed that the STAT3 expression was an independent prognostic factor for DLBCL patients regardless of CHOP or R-CHOP regimen used as the first-line therapy. Conclusion STAT3 is more frequently expressed in non-GCB DLBCL than that in GCB subtype, and its strong nuclear expression is correlated with poor OS in DLBCL.

  1. Hepatic Stellate Cell Coculture Enables Sorafenib Resistance in Huh7 Cells through HGF/c-Met/Akt and Jak2/Stat3 Pathways

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    Weibo Chen

    2014-01-01

    Full Text Available Purpose. Tumor microenvironment confers drug resistance to kinase inhibitors by increasing RKT ligand levels that result in the activation of cell-survival signaling including PI3K and MAPK signals. We assessed whether HSC-LX2 coculture conferred sorafenib resistance in Huh7 and revealed the mechanism underlying the drug resistance. Experimental Design. The effect of LX2 on sorafenib resistance was determined by coculture system with Huh7 cells. The rescue function of LX2 supernatants was assessed by MTT assay and fluorescence microscopy. The underlying mechanism was tested by administration of pathway inhibitors and manifested by Western blotting. Results. LX2 coculture significantly induced sorafenib resistance in Huh7 by activating p-Akt that led to reactivation of p-ERK. LX2 secreted HGF into the culture medium that triggered drug resistance, and exogenous HGF could also induce sorafenib resistance. The inhibition of p-Akt blocked sorafenib resistance caused by LX2 coculture. Increased phosphorylation of Jak2 and Stat3 was also detected in LX2 cocultured Huh7 cells. The Jak inhibitor tofacitinib reversed sorafenib resistance by blocking Jak2 and Stat3 activation. The combined administration of sorafenib and p-Stat3 inhibitor S3I-201 augmented induced apoptosis even in the presence of sorafenib resistance. Conclusions. HSC-LX2 coculture induced sorafenib resistance in Huh7 through multiple pathways: HGF/c-Met/Akt pathway and Jak2/Stat3 pathway. A combined administration of sorafenib and S3I-201 was able to augment sorafenib-induced apoptosis even in the presence of LX2 coculture.

  2. Study on intracellular calcium concentration and calcium current of osteoblast in Stat3 knockout mice%Stat3基因敲除小鼠成骨细胞内钙和钙通道电流变化特性的研究

    Institute of Scientific and Technical Information of China (English)

    李磊; 王俊成; 刘颖新; 任晖; 李春龙

    2015-01-01

    目的:研究Stat3基因敲除小鼠成骨细胞内钙和钙通道电流的变化特性。方法应用PCR技术对Stat3基因敲除小鼠进行鉴定;采用二次酶消化法分离、培养小鼠的原代成骨细胞;通过激光扫描共聚焦技术测定细胞内游离钙离子浓度([Ca2+]i);应用全细胞膜片钳技术记录成骨细胞膜钙通道电流( ICa)的变化。结果共聚焦结果显示Stat3基因敲除小鼠与正常小鼠相比,细胞内[ Ca2+] i 明显升高(P<0.01)。膜片钳结果显示,刺激电压为+10mV时,Stat3基因敲除组ICa为(-443.03±49.03)pA,与正常组[(-325.19±38.40)pA]相比,明显增加(P<0.01)。结论 Stat3基因敲除小鼠成骨细胞伴有明显的[ Ca2+] i的异常,其机制可能与细胞膜上钙通道活性改变有关。%Objective To investigate the character of intracellar calcium concentration ( [ Ca2+] ) i and calcium current ( ICa) of osteoblast in Stat3 knockout mice.Methods PCR was used to identify Stat3 knockout mice.The first generation of osteoblast was isolated and purified from the mice by sequential enzyme digestion. [ Ca2+] i was detected by laser scanning confocal microscopy, and the changes of ICa were recorded by whole-cell patch-clamp technique.Results Confocal experiments showed that [ Ca2+] i was markedly increased in Stat3 knockout mice, compared with that in control mice (P<0.01).Patch-clamp studies displayed that at +10mV, the ICa was (-443.03 ±49.03) pA and ( -325.19 ±38.40) pA in Stat3 knockout mice group and control group, respectively.ICa was obvious difference between two groups (P <0.01).Conclusions [Ca2+]i of osteoblast is abnormal in Stat3 knockout mice, and the mechanisms are associated with the changes of electrophysiological activity of calcium channel.

  3. Hydrogen sulfide postconditioning protects isolated rat hearts against ischemia and reperfusion injury mediated by the JAK2/STAT3 survival pathway

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    Heng-Fei Luan

    2012-10-01

    Full Text Available The JAK2/STAT3 signal pathway is an important component of survivor activating factor enhancement (SAFE pathway. The objective of the present study was to determine whether the JAK2/STAT3 signaling pathway participates in hydrogen sulfide (H2S postconditioning, protecting isolated rat hearts from ischemic-reperfusion injury. Male Sprague-Dawley rats (230-270 g were divided into 6 groups (N = 14 per group: time-matched perfusion (Sham group, ischemia/reperfusion (I/R group, NaHS postconditioning group, NaHS with AG-490 group, AG-490 (5 µM group, and dimethyl sulfoxide (DMSO; <0.2% group. Langendorff-perfused rat hearts, with the exception of the Sham group, were subjected to 30 min of ischemia followed by 90 min of reperfusion after 20 min of equilibrium. Heart rate, left ventricular developed pressure (LVDP, left ventricular end-diastolic pressure (LVEDP, and the maximum rate of increase or decrease of left ventricular pressure (± dp/dt max were recorded. Infarct size was determined using triphenyltetrazolium chloride (TTC staining. Myocardial TUNEL staining was used as the in situ cell death detection method and the percentage of TUNEL-positive nuclei to all nuclei counted was used as the apoptotic index. The expression of STAT3, bcl-2 and bax was determined by Western blotting. After reperfusion, compared to the I/R group, H2S significantly improved functional recovery and decreased infarct size (23.3 ± 3.8 vs 41.2 ± 4.7%, P < 0.05 and apoptotic index (22.1 ± 3.6 vs 43.0 ± 4.8%, P < 0.05. However, H2S-mediated protection was abolished by AG-490, the JAK2 inhibitor. In conclusion, H2S postconditioning effectively protects isolated I/R rat hearts via activation of the JAK2/STAT3 signaling pathway.

  4. α-Solanine inhibits vascular endothelial growth factor expression by down-regulating the ERK1/2-HIF-1α and STAT3 signaling pathways.

    Science.gov (United States)

    Wen, Zhengde; Huang, Chaohao; Xu, Yaya; Xiao, Yuwu; Tang, Lili; Dai, Juji; Sun, Hongwei; Chen, Bicheng; Zhou, Mengtao

    2016-01-15

    In tumors, vascular endothelial growth factor (VEGF) contributes to angiogenesis, vascular permeability, and tumorigenesis. In our previous study, we found that α-solanine, which is widespread in solanaceae, has a strong anti-cancer effect under normoxia. However, it is unknown whether α-solanine has a similar effect under hypoxia. We used cobalt chloride (CoCl2) to mimic hypoxia in vitro. HIF-1α, which is almost undetectable under normoxia, was significantly increased. Simultaneously, another regulator of VEGF, STAT3, was also significantly activated by CoCl2. We utilized α-solanine in co-culture with CoCl2. α-solanine decreased the expression of VEGF and loss of E-cadherin. α-solanine also suppressed the activation of phospho-ERK1/2 (p-ERK1/2), HIF-1α, and STAT3 signaling. The results provide new evidence that α-solanine has a strong anti-cancer effect via the ERK1/2-HIF-1α and STAT3 signaling pathways and suggest that it may be a potential new drug.

  5. Hydrazinocurcumin Encapsuled nanoparticles "re-educate" tumor-associated macrophages and exhibit anti-tumor effects on breast cancer following STAT3 suppression.

    Directory of Open Access Journals (Sweden)

    Xiwen Zhang

    Full Text Available Tumor-associated macrophages (TAMs are essential cellular components within tumor microenvironment (TME. TAMs are educated by TME to transform to M2 polarized population, showing a M2-like phenotype, IL-10(high, IL-12(low, TGF-β(high. STAT3 signaling triggers crosstalk between tumor cells and TAMs, and is crucial for the regulation of malignant progression. In our study, legumain-targeting liposomal nanoparticles (NPs encapsulating HC were employed to suppress STAT3 activity and "re-educate" TAMs, and to investigate the effects of suppression of tumor progression in vivo. The results showed that TAMs treated by HC encapsuled NPs could switch to M1-like phenotype, IL-10(low, IL-12(high, TGF-β(low, and the "re-educated" macrophages (M1-like macrophages considerably demonstrated opposite effect of M2-like macrophages, especially the induction of 4T1 cells migration and invasion in vitro, and suppression of tumor growth, angiogenesis and metastasis in vivo. These data indicated that inhibition of STAT3 activity of TAMs by HC-NPs was able to reverse their phenotype and could regulate their crosstalk between tumor cells and TAMs in order to suppress tumor progression.

  6. 寻常型银屑病皮损中Stat3和Survivin的表达及相关性分析%The expression of Stat3 and Survivin in the lesions of psoriasis vulgaris and their correlation

    Institute of Scientific and Technical Information of China (English)

    冯世军; 高顺强; 李华蕊; 马敬; 李萍

    2012-01-01

    Objective To investigate the expression of Stat3 and Survivin in the lesions of psoriasis vulgaris and their correlation. Methods The expressions of Stat3 and Survivin in 52 patients with psoriasis vulgaris were detected by immunohistochemistry, and the correlation between Stat3 and Survivin expression was analyzed. Results The expressions of Stat3 and Survivin were significantly up-regulated, as compared with those in control group( P < 0. 05 ). The expression of Stat3 was positively correlated with that of Survivin in patients with psoriasis vulgaris ( P < 0. 01 ). Conclusion The Stat3 and Survivin are over-expressed in psoriasis vulgaris. Survivin can promote the proliferation of keratinocyte in the lesions of psoriasis vulgaris by up-regulating the expression of Survivin, which may play an important role in the pathogenesis and development of psoriasis vulgaris.%目的 探讨信号传导及转录活化因子3( Stat3)及生存素(Survivin)在寻常型银屑病皮损中的表达及其相关性.方法 通过免疫组化方法研究52例寻常型银屑病皮损中Stat3及Survivin表达的情况,并探讨Stat3和Survivin表达的相关性.结果 寻常型银屑病皮损中Stat3的表达和凋亡抑制蛋白Survivin的表达与正常对照组相比均明显上调(P<0.05).银屑病患者Stat3表达和Survivin表达呈正相关(P<0.01).结论 寻常型银屑病皮损中存在Stat3和Survivin的高表达,Stat3可能通过上调Survivin的表达,促进银屑病皮损处角质形成细胞的增殖,在寻常型银屑病的发生发展中起重要作用.

  7. STAT3 signaling controls satellite cell expansion and skeletal muscle repair

    OpenAIRE

    Tierney, Matthew Timothy; Aydogdu, Tufan; Sala, David; Malecova, Barbora; Gatto, Sole; Puri, Pier Lorenzo; Latella, Lucia; Sacco, Alessandra

    2014-01-01

    The progression of disease- and age-dependent skeletal muscle wasting results in part from a decline in the number and function of satellite cells, the direct cellular contributors to muscle repair1–10. However, little is known about the molecular effectors underlying satellite cell impairment and depletion. Elevated levels of inflammatory cytokines, including interleukin-6 (IL-6), are associated with both age-related and muscle-wasting conditions11–13. The levels of STAT3, a downstream effec...

  8. Role of STAT3 in regulatory T lymphocyte plasticity during acute graft-vs.-host-disease

    OpenAIRE

    Fujino, Masayuki; Li, Xiao-Kang

    2013-01-01

    Regulatory T (Treg) lymphocytes are important mediators of the allogeneic immune response, although the mechanisms by which they are control