278 results on '"STAT3 Transcription Factor drug effects"'
Search Results
202. Signal transducer and activator of transcription 3 is a major kinase-independent target of sorafenib in hepatocellular carcinoma.
- Author
-
Tai WT, Cheng AL, Shiau CW, Huang HP, Huang JW, Chen PJ, and Chen KF
- Subjects
- Animals, Apoptosis drug effects, Carcinoma, Hepatocellular enzymology, Cell Line, Tumor, Down-Regulation, Humans, Liver Neoplasms enzymology, Mice, Mice, Nude, Niacinamide analogs & derivatives, Phenylurea Compounds, Protein Tyrosine Phosphatase, Non-Receptor Type 6 drug effects, Protein Tyrosine Phosphatase, Non-Receptor Type 6 metabolism, Proto-Oncogene Proteins c-raf metabolism, STAT3 Transcription Factor metabolism, Signal Transduction drug effects, Sorafenib, Benzenesulfonates pharmacology, Carcinoma, Hepatocellular drug therapy, Liver Neoplasms drug therapy, Protein Kinase Inhibitors pharmacology, Pyridines pharmacology, STAT3 Transcription Factor drug effects
- Abstract
Background & Aims: Recently, we reported that sorafenib sensitizes hepatocellular carcinoma (HCC) cells to TRAIL through the inhibition of signal transducer and activator of transcription 3 (STAT3). Here, we report that sorafenib inhibits HCC via a kinase-independent mechanism: SHP-1 dependent STAT3 inactivation., Methods: SC-1 is a sorafenib derivative that closely resembles sorafenib structurally but with no kinase inhibition activity. HCC cell lines (PLC5, Huh-7, Hep3B, and Sk-Hep1) were treated with sorafenib or SC-1 and apoptosis and signal transduction were analyzed. In vivo efficacy was determined in nude mice with Huh-7 xenografts., Results: SC-1 showed similar effects to sorafenib on growth inhibition and apoptosis in all tested HCC cell lines. SC-1 down-regulated phosphorylation of phospho-STAT3 (p-STAT3) at tyrosine 705 in all tested HCC cells. Expression of STAT3-driven genes, including Cyclin D1 and Survivin, was also repressed by SC-1. Luciferase reporter assay confirmed the inhibition of transcriptional activity of STAT3 in both sorafenib-treated and SC-1-treated cells. Ectopic expression of STAT3 in PLC5 cells abolished apoptosis in SC-1-treated cells. Sorafenib and SC-1 up-regulated SHP-1 activity. Knockdown of SHP-1, but not SHP-2 or PTP-1B, by small interference RNA reduced apoptosis induced by SC-1. Finally, SC-1 reduced Huh-7 tumor growth significantly in vivo, which was associated with down-regulation of p-STAT3 and up-regulation of SHP-1 activity., Conclusions: STAT3 is a major kinase-independent target of sorafenib in HCC., (Copyright © 2011 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
203. Influence of Janus kinase inhibition on interleukin 6-mediated induction of acute-phase serum amyloid A in rheumatoid synovium.
- Author
-
Migita K, Koga T, Komori A, Torigoshi T, Maeda Y, Izumi Y, Sato J, Jiuchi Y, Miyashita T, Yamasaki S, Kawakami A, Nakamura M, Motokawa S, and Ishibashi H
- Subjects
- Arthritis, Rheumatoid pathology, Cells, Cultured, Enzyme Inhibitors pharmacology, Humans, Janus Kinase 2 antagonists & inhibitors, Janus Kinase 2 drug effects, Janus Kinase 3 antagonists & inhibitors, Janus Kinase 3 drug effects, Janus Kinases drug effects, Piperidines, Pyrimidines pharmacology, Pyrroles pharmacology, RNA, Messenger metabolism, STAT3 Transcription Factor antagonists & inhibitors, STAT3 Transcription Factor drug effects, Signal Transduction drug effects, Synovial Membrane pathology, Acute-Phase Reaction metabolism, Arthritis, Rheumatoid metabolism, Interleukin-6 pharmacology, Janus Kinases antagonists & inhibitors, Serum Amyloid A Protein metabolism, Synovial Membrane drug effects, Synovial Membrane metabolism
- Abstract
Objective: Inhibition of intracellular signal transduction is considered to be a therapeutic target for chronic inflammation. The new Janus kinase (JAK)3 inhibitor CP690,550 has shown efficacy in the treatment of rheumatoid arthritis (RA). We investigated the influence of JAK/STAT inhibition using CP690,550 on the induction of acute-phase serum amyloid A (SAA), which is triggered by interleukin 6 (IL-6) stimulation in rheumatoid fibroblast-like synoviocytes (RA-FLS)., Methods: IL-6-stimulated gene expression of the acute-phase serum amyloid A genes (A-SAA; encoded by SAA1+SAA2) and SAA4 was analyzed by reverse transcriptase-polymerase chain reaction. The intracellular signaling pathway mediating the effects of CP690,550 on IL-6-stimulated JAK/STAT activation was assessed by measuring the phosphorylation levels using Western blots., Results: IL-6 trans-signaling induced A-SAA messenger RNA (mRNA) expression in RA-FLS. By contrast IL-6 stimulation did not affect SAA4 mRNA expression, which is expressed constitutively in RA-FLS. IL-6 stimulation elicited rapid phosphorylation of JAK2 and STAT3, which was blunted by CP690,550. CP690,550 abrogated IL-6-mediated A-SAA mRNA expression in RA-FLS. Similarly, CP690,550 inhibited IL-6-mediated A-SAA mRNA expression in human hepatocytes., Conclusion: Our data indicated that CP690,550 blocked IL-6-induced JAK2/STAT3 activation, as well as the induction of A-SAA. Inhibition of IL-6-mediated proinflammatory signaling pathways by CP690,550 may represent a new antiinflammatory therapeutic strategy for RA and AA amyloidosis.
- Published
- 2011
- Full Text
- View/download PDF
204. The gold compound auranofin induces apoptosis of human multiple myeloma cells through both down-regulation of STAT3 and inhibition of NF-κB activity.
- Author
-
Nakaya A, Sagawa M, Muto A, Uchida H, Ikeda Y, and Kizaki M
- Subjects
- Blotting, Western, Cell Cycle drug effects, Cell Line, Tumor, Down-Regulation, Enzyme-Linked Immunosorbent Assay, Gene Expression drug effects, Humans, Myeloid Cell Leukemia Sequence 1 Protein, NF-kappa B drug effects, NF-kappa B metabolism, Proto-Oncogene Proteins c-bcl-2 drug effects, Proto-Oncogene Proteins c-bcl-2 metabolism, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Transfection, Antineoplastic Agents pharmacology, Apoptosis drug effects, Auranofin pharmacology, Multiple Myeloma metabolism, Signal Transduction drug effects
- Abstract
Constitutive activation of NF-κB and STAT3 plays an important role in the cellular proliferation and survival of multiple myeloma cells. We first found that auranofin (AF), a coordinated gold compound, induced a significant level of cell cycle arrest at G1 phase and subsequent apoptosis of myeloma cells. Further, AF inhibited constitutive and IL-6-induced activation of JAK2 and phosphorylation of STAT3 followed by the decreased expression of Mcl-1. AF down-regulated the activation of NF-κB, and the combination of AF and a specific NF-κB inhibitor resulted in a marked decrease of Mcl-1 expression. These results suggest that AF inhibits both IL-6 induced-JAK/STAT pathway and NF-κB activation in myeloma cells., (Copyright © 2010 Elsevier Ltd. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
205. Bisphosphonates inhibit phosphorylation of signal transducer and activator of transcription 3 and expression of suppressor of cytokine signaling 3: implications for their effects on innate immune function and osteoclastogenesis.
- Author
-
Reuben JS, Dinh L, Lee J, Stateson J, Kamara H, Xiang L, and Opperman LA
- Subjects
- Animals, Cell Differentiation drug effects, Cell Survival drug effects, Cells, Cultured, Clodronic Acid pharmacology, Dose-Response Relationship, Drug, Ibandronic Acid, Immunity, Innate drug effects, Macrophages metabolism, Mice, Osteoclasts cytology, Osteoclasts drug effects, STAT3 Transcription Factor metabolism, Suppressor of Cytokine Signaling 3 Protein, Suppressor of Cytokine Signaling Proteins metabolism, Bone Density Conservation Agents pharmacology, Diphosphonates pharmacology, Macrophages drug effects, STAT3 Transcription Factor drug effects, Suppressor of Cytokine Signaling Proteins drug effects
- Abstract
Objective: This study tested the effects of bisphosphonates (BPs) on the suppressor of cytokine signaling 3 (SOCS3) protein in macrophages. SOCS3 has been shown to regulate cell differentiation and survival; however, its potential role in mediating the effects of BPs has not been explored., Study Design: The cell viability of murine RAW 267.4 macrophages was assessed after culturing with control medium or media containing increasing concentrations of 2 BPs (ibandronate or clodronate) for 24, 48, and 72 hours. The phosphorylation status of signal transducer and activator of transcription 3 (STAT3) and the expression of SOCS3 protein levels were determined by Western blot analysis., Results: In control cultures, STAT3 phosphorylation and STAT3 and SOCS3 protein levels increased within 5 minutes after the addition of fresh medium. This increase was inhibited in cultures treated with both BPs. Macrophage cell viability also decreased after BP treatment., Conclusions: These data demonstrate that, in addition to their effects on macrophage viability, BPs can decrease STAT3 and SOCS3 expression, which are important modulators of immune responses and bone homeostasis., (Copyright © 2011 Mosby, Inc. All rights reserved.)
- Published
- 2011
- Full Text
- View/download PDF
206. Effects of S/B remedy containing Scutellaria baicalensis and Bupleurum scorzonerifolfium on hepatic interleukin-6 related signal transducer and activator of transcription 3 activation in mice through cell-cell interaction.
- Author
-
Lee CY, Wang JY, Chen TC, Jiang JK, Peng CH, Kuo CD, Chang WC, Chiu JH, and Wu CW
- Subjects
- Animals, Base Sequence, Blotting, Western, DNA Primers, Liver metabolism, Mice, Mice, Inbred C57BL, Reverse Transcriptase Polymerase Chain Reaction, STAT3 Transcription Factor metabolism, Bupleurum chemistry, Liver drug effects, Plant Extracts pharmacology, STAT3 Transcription Factor drug effects, Scutellaria baicalensis chemistry
- Abstract
Signal transducer and activator of transcription 3 (STAT3) plays an important role in regulating interleukin 6 (IL-6) related growth control of the liver. Our previous study demonstrated that a mixture containing Scutellaria baicalensis and Bupleurum scorzonerifolfium (S/B remedy) modulated the growth of hepatocytes during liver regeneration after 2/3 partial hepatectomy. The aim of this study was to investigate whether S/B remedy induced mouse hepatic STAT3 activation directly in hepatocytes or indirectly via non-parenchymal cell-hepatocyte interaction. Direct S/B remedy effects were studied using primarily isolated hepatocytes; while C57BL/6J mice were used to study indirect effects of S/B remedy using gadolinium chloride to deplete Kupffer cells' function. The results showed that S/B remedy and its active constituents did not directly activate growth-related signaling in primarily isolated hepatocytes. However, S/B remedy induced STAT3 and subsequently suppressor of cytokine signaling (SOCS3) activation in mouse liver and increased serum IL-6 level in a dose-dependent manner, which could be partially blocked by pretreatment with gadolinium chloride. Oligonucloetide microarray analysis from S/B remedy-treated peripheral blood leukocytes demonstrated an up-regulation of IL-6 gene expression. We conclude that S/B remedy did not directly induce STAT3 activation in vitro, but induced hepatic IL-6 related STAT3 activation through non-parenchymal cell-hepatocyte interaction in vivo. The results provide important information on the molecular mechanisms of S/B remedy for treatment of human liver diseases.
- Published
- 2011
- Full Text
- View/download PDF
207. Safety and efficacy of INCB018424, a JAK1 and JAK2 inhibitor, in myelofibrosis.
- Author
-
Verstovsek S, Kantarjian H, Mesa RA, Pardanani AD, Cortes-Franco J, Thomas DA, Estrov Z, Fridman JS, Bradley EC, Erickson-Viitanen S, Vaddi K, Levy R, and Tefferi A
- Subjects
- Adult, Aged, Aged, 80 and over, Anemia drug therapy, Anemia etiology, Biomarkers blood, Cytokines blood, Dose-Response Relationship, Drug, Female, Hepatomegaly drug therapy, Hepatomegaly etiology, Humans, Janus Kinase 2 genetics, Male, Middle Aged, Mutation, Nitriles, Primary Myelofibrosis blood, Primary Myelofibrosis complications, Primary Myelofibrosis genetics, Pyrimidines, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Spleen drug effects, Spleen pathology, Janus Kinase 1 antagonists & inhibitors, Janus Kinase 2 antagonists & inhibitors, Primary Myelofibrosis drug therapy, Pyrazoles administration & dosage, Pyrazoles adverse effects
- Abstract
Background: Myelofibrosis is a Philadelphia chromosome–negative myeloproliferative neoplasm associated with cytopenias, splenomegaly, poor quality of life, and shortened survival. About half of patients with myelofibrosis carry a gain-of-function mutation in the Janus kinase 2 gene (JAK2 V617F) that contributes to the pathophysiology of the disease. INCB018424 is a potent and selective Janus kinase 1 (JAK1) and JAK2 inhibitor., Methods: We conducted a phase 1−2 trial of INCB018424 in patients with JAK2 V617F−positive or JAK2 V617F−negative primary myelofibrosis, post–essential thrombocythemia myelofibrosis, or post–polycythemia vera myelofibrosis., Results: A total of 153 patients received INCB018424 for a median duration of more than 14.7 months. The initial dose-escalation phase established 25 mg twice daily or 100 mg once daily as maximum tolerated doses, on the basis of reversible thrombocytopenia. A dose-dependent suppression of phosphorylated signal transducer and activator of transcription 3 (STAT3), a marker of JAK signaling, was demonstrated in patients with wild-type JAK2 and in patients with the JAK2 V617F mutation. We studied additional doses and established that a 15-mg twice-daily starting dose, followed by individualized dose titration, was the most effective and safest dosing regimen. At this dose, 17 of 33 patients (52%) had a rapid objective response (≥50% reduction of splenomegaly) lasting for 12 months or more, and this therapy was associated with grade 3 or grade 4 adverse events (mainly myelosuppression) in less than 10% of patients. Patients with debilitating symptoms, including weight loss, fatigue, night sweats, and pruritus, had rapid improvement. Clinical benefits were associated with a marked diminution of levels of circulating inflammatory cytokines that are commonly elevated in myelofibrosis., Conclusions: INCB018424 was associated with marked and durable clinical benefits in patients with myelofibrosis for whom no approved therapies existed. (Funded by Incyte; ClinicalTrials.gov number, NCT00509899.), Competing Interests: No other potential conflict of interest relevant to this article was reported.
- Published
- 2010
- Full Text
- View/download PDF
208. Cucurbitacin B induces apoptosis and S phase cell cycle arrest in BEL-7402 human hepatocellular carcinoma cells and is effective via oral administration.
- Author
-
Chan KT, Meng FY, Li Q, Ho CY, Lam TS, To Y, Lee WH, Li M, Chu KH, and Toh M
- Subjects
- Administration, Oral, Animals, Antineoplastic Agents pharmacology, Blotting, Western, Carcinoma, Hepatocellular drug therapy, Cell Division drug effects, Cell Line, Tumor, Flow Cytometry, Humans, Liver Neoplasms drug therapy, Mice, Mice, Nude, Proto-Oncogene Proteins c-raf metabolism, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Transplantation, Heterologous, Antineoplastic Agents therapeutic use, Apoptosis drug effects, Carcinoma, Hepatocellular pathology, Cell Cycle drug effects, Liver Neoplasms pathology, S Phase drug effects, Triterpenes pharmacology, Triterpenes therapeutic use
- Abstract
Cucurbitacin B is an anti-cancer drug candidate and its efficacy has been demonstrated in hepatocellular carcinoma (HCC). To explore its mechanism against HCC, BEL-7402 cells were treated with cucurbitacin B in vitro. Treatment with cucurbitacin B induced S phase arrest and apoptosis. The growth inhibition effect was associated with cyclin D1 and cdc-2 down regulations. Western blotting analysis of cell signaling molecules indicated that cucurbitacin B inhibited c-Raf activation without affecting STAT3 phosphorylation. Moreover, in vivo study demonstrated that cucurbitacin B is effective against BEL-7402 xenograft when administrated orally., (Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
209. Activation of the JAK-STAT pathway by olanzapine is necessary for desensitization of serotonin2A receptor-stimulated phospholipase C signaling in rat frontal cortex but not serotonin2A receptor-stimulated hormone release.
- Author
-
Singh RK, Jia C, Garcia F, Carrasco GA, Battaglia G, and Muma NA
- Subjects
- Adrenocorticotropic Hormone blood, Animals, Blotting, Western, Corticosterone blood, Enzyme Inhibitors pharmacology, Janus Kinase 2 antagonists & inhibitors, Male, Olanzapine, Paraventricular Hypothalamic Nucleus drug effects, Paraventricular Hypothalamic Nucleus metabolism, Phosphorylation, Prefrontal Cortex enzymology, RGS Proteins biosynthesis, RNA, Messenger biosynthesis, RNA, Messenger genetics, Rats, Rats, Sprague-Dawley, Reverse Transcriptase Polymerase Chain Reaction, STAT3 Transcription Factor antagonists & inhibitors, Tyrphostins pharmacology, Antipsychotic Agents pharmacology, Benzodiazepines pharmacology, Hormones metabolism, Janus Kinase 2 drug effects, Prefrontal Cortex drug effects, Receptor, Serotonin, 5-HT2A drug effects, STAT3 Transcription Factor drug effects, Selective Serotonin Reuptake Inhibitors pharmacology, Signal Transduction drug effects, Type C Phospholipases physiology
- Abstract
Chronic treatment with olanzapine causes desensitization of serotonin 2A receptor signaling. The purpose of the current study was to further understand the mechanisms underlying this desensitization response of serotonin 2A receptor signaling in vivo. We report that desensitization of serotonin 2A receptor stimulated-phospholipase C activity in rat frontal cortex induced by olanzapine is dependent on the activation of the JAK-STAT pathway. Olanzapine treatment for 7 days significantly increased the levels of the regulator of G protein signaling (RGS7) protein, RGS7 mRNA levels, and activation of JAK2 in rat frontal cortex. Pre-treatment with a JAK2 inhibitor AG490, significantly attenuated the olanzapine-induced reductions in serotonin 2A receptor-stimulated phospholipase C activity and prevented the olanzapine-induced increases in RGS7 mRNA and protein levels. In contrast, inhibition of the JAK-STAT pathway with AG490 did not reverse the olanzapine-induced desensitization of the serotonin 2A receptor pathway in the hypothalamic paraventricular nucleus mediating increases in plasma hormone levels. AG490 dose-dependently inhibited serotonin 2A receptor-stimulated oxytocin and corticosterone release. These results suggest that the olanzapine-induced increase in RGS7 expression is mediated by the activation of JAK-STAT and is necessary for olanzapine-induced desensitization of serotonin 2A receptor-stimulated phospholipase C activity in the frontal cortex but not serotonin 2A receptor-stimulated hormone release.
- Published
- 2010
- Full Text
- View/download PDF
210. Naphtho[1,2-b]furan-4,5-dione disrupts Janus kinase-2 and induces apoptosis in breast cancer MDA-MB-231 cells.
- Author
-
Lin KL, Su JC, Chien CM, Tseng CH, Chen YL, Chang LS, and Lin SR
- Subjects
- Breast Neoplasms enzymology, Cell Line, Tumor, Female, Humans, Inhibitor of Apoptosis Proteins drug effects, Inhibitor of Apoptosis Proteins metabolism, Phosphatidylinositol 3-Kinases drug effects, Phosphatidylinositol 3-Kinases metabolism, Phosphorylation drug effects, Protein Kinase Inhibitors toxicity, Proto-Oncogene Proteins c-akt drug effects, Proto-Oncogene Proteins c-akt metabolism, Proto-Oncogene Proteins c-bcl-2 drug effects, Proto-Oncogene Proteins c-bcl-2 metabolism, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, src-Family Kinases drug effects, src-Family Kinases metabolism, Antineoplastic Agents toxicity, Apoptosis drug effects, Breast Neoplasms metabolism, Janus Kinase 2 metabolism, Naphthoquinones toxicity
- Abstract
Naphtho[1,2-b]furan-4,5-dione (NFD), prepared from 2-hydroxy-1,4-naphthoquinone and chloroacetaldehyde in an efficient one-pot reaction, exhibits an anti-carcinogenic effect. NFD-induced apoptosis in MDA-MB-231 cells, as indicated by the accumulation of sub-G1 population, externalization of phosphatidylserine, loss of mitochondrial membrane potential (DeltaPsim) with subsequent release of cytochrome c, and activation of both capase-9 and caspase-3. This correlated with up-regulation in Bax and Bad, and down-regulation of various anti-apoptotic proteins, including Bcl-2, Bcl-X(L), Mcl-1, and survivin in NFD-treated cells. In the analysis of signal transduction pathway, NFD suppressed the phosphorylation of JAK2 in MDA-MB-231 cells without altering the expression of JAK2 protein. Activation of STAT3, Src, and PI3K/Akt were also inhibited by NFD. Moreover, the JAK2 inhibitor AG490 blocked JAK2, STAT3, Src, PI3K, and Akt activation, whereas both Src inhibitor PP2 and PI3K inhibitor wortmannin did not affect JAK2 activation. This suggests that STAT3, Src, and PI3K/Akt are downstream molecules of the JAK2 signaling pathway. AG490 treatment also mimics the cytotoxic effects of NFD. Taken together, these results indicate that NFD disrupts JAK2 pathway and induces apoptosis in MDA-MB-231 cells., (Copyright 2010 Elsevier Ltd. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
211. Arecoline induces HA22T/VGH hepatoma cells to undergo anoikis - involvement of STAT3 and RhoA activation.
- Author
-
Cheng HL, Su SJ, Huang LW, Hsieh BS, Hu YC, Hung TC, and Chang KL
- Subjects
- Animals, Blotting, Western, Carcinoma, Hepatocellular pathology, Cell Adhesion drug effects, Cell Line, Tumor, Cell Separation, DNA Fragmentation drug effects, Flow Cytometry, Fluorescent Antibody Technique, Humans, In Situ Nick-End Labeling, Liver Neoplasms pathology, Rats, Rats, Sprague-Dawley, Reverse Transcriptase Polymerase Chain Reaction, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Signal Transduction drug effects, Signal Transduction physiology, rhoA GTP-Binding Protein drug effects, rhoA GTP-Binding Protein metabolism, Anoikis drug effects, Antineoplastic Agents pharmacology, Arecoline pharmacology, Carcinoma, Hepatocellular metabolism, Enzyme Activation drug effects, Liver Neoplasms metabolism
- Abstract
Background: Our previous study showed that, in basal cell carcinoma cells, arecoline reduces levels of the tumor cell survival factor interleukin-6 (IL-6), increases levels of tumor suppressor factor p53, and elicits cell cycle arrest, followed by apoptosis. In preliminarily studies, we observed that arecoline induces detachment of the human-derived hepatoma cell line HA22T/VGH from the extracellular matrix. In the present study, we explored the fate of the detached HA22T/VGH cells and investigated the underlying mechanism., Methods: HA22T/VGH cells or primary cultured rat hepatocytes were treated with arecoline, then changes in morphology, viability, apoptosis, and the expression of surface beta1-integrin, apoptosis-related proteins, and IL-6 were examined. Furthermore, activation of the signal transducer and activator of transcription 3 (STAT3) pathway and the RhoA/Rock signaling pathway, including p190RhoGAP and Src homology-2 domain-containing phosphatase SHP2, was examined., Results: A low concentration of arecoline (
- Published
- 2010
- Full Text
- View/download PDF
212. A novel small-molecule disrupts Stat3 SH2 domain-phosphotyrosine interactions and Stat3-dependent tumor processes.
- Author
-
Zhang X, Yue P, Fletcher S, Zhao W, Gunning PT, and Turkson J
- Subjects
- Aminosalicylic Acids pharmacology, Animals, Breast Neoplasms physiopathology, Cell Line, Cell Line, Tumor, Cell Transformation, Neoplastic drug effects, Cell Transformation, Neoplastic metabolism, DNA, Neoplasm drug effects, DNA, Neoplasm metabolism, ErbB Receptors drug effects, ErbB Receptors physiology, Female, Fluorescence Polarization Immunoassay, Gene Expression Regulation, Neoplastic physiology, Humans, Mice, Mice, Nude, Pancreatic Neoplasms physiopathology, STAT3 Transcription Factor antagonists & inhibitors, STAT3 Transcription Factor genetics, STAT3 Transcription Factor metabolism, STAT3 Transcription Factor physiology, Surface Plasmon Resonance, Transcriptional Activation drug effects, Transcriptional Activation physiology, src Homology Domains physiology, Benzenesulfonates pharmacology, Gene Expression Regulation, Neoplastic drug effects, STAT3 Transcription Factor drug effects, src Homology Domains drug effects
- Abstract
The molecular modeling of the phosphotyrosine (pTyr)-SH2 domain interaction in the Stat3:Stat3 dimerization, combined with in silico structural analysis of the Stat3 dimerization disruptor, S3I-201, has furnished a diverse set of analogs. We present evidence from in vitro biochemical and biophysical studies that the structural analog, S3I-201.1066 directly interacts with Stat3 or the SH2 domain, with an affinity (K(D)) of 2.74microM, and disrupts the binding of Stat3 to the cognate pTyr-peptide, GpYLPQTV-NH(2), with an IC(50) of 23microM. Moreover, S3I-201.1066 selectively blocks the association of Stat3 with the epidermal growth factor receptor (EGFR), and inhibits Stat3 tyrosine phosphorylation and nuclear translocation in EGF-stimulated mouse fibroblasts. In cancer cells that harbor aberrant Stat3 activity, S3I-201.1066 inhibits constitutive Stat3 DNA-binding and transcriptional activities. By contrast, S3I-201.1066 has no effect on Src activation or the EGFR-mediated activation of the Erk1/2(MAPK) pathway. S3I-201.1066 selectively suppresses the viability, survival, and malignant transformation of the human breast and pancreatic cancer lines and the v-Src-transformed mouse fibroblasts harboring persistently active Stat3. Treatment with S3I-201.1066 of malignant cells harboring aberrantly active Stat3 down-regulated the expression of c-Myc, Bcl-xL, Survivin, the matrix metalloproteinase 9, and VEGF. The in vivo administration of S3I-201.1066-induced significant antitumor response in mouse models of human breast cancer, which correlates with the inhibition of constitutively active Stat3 and the suppression of known Stat3-regulated genes. Our studies identify a novel small-molecule that binds with a high affinity to Stat3, blocks Stat3 activation and function, and thereby induces antitumor response in human breast tumor xenografts harboring persistently active Stat3., (2010 Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
213. Paracrine factors from human placental multipotent mesenchymal stromal cells protect endothelium from oxidative injury via STAT3 and manganese superoxide dismutase activation.
- Author
-
Liu SH, Huang JP, Lee RK, Huang MC, Wu YH, Chen CY, and Chen CP
- Subjects
- Apoptosis drug effects, Apoptosis physiology, Cell Survival drug effects, Culture Media, Conditioned pharmacology, Endothelial Cells drug effects, Female, Humans, Interleukin-6 metabolism, Oxidative Stress drug effects, Oxidative Stress physiology, Paracrine Communication physiology, Placenta metabolism, Pregnancy, STAT3 Transcription Factor drug effects, Superoxide Dismutase drug effects, Endothelial Cells metabolism, Mesenchymal Stem Cells metabolism, Multipotent Stem Cells metabolism, Placenta cytology, STAT3 Transcription Factor physiology, Superoxide Dismutase metabolism
- Abstract
Reactive oxygen species may cause oxidative damage in the placenta, yet some mechanisms must exist to reduce or prevent such damage. We investigated whether oxidative injury to placental endothelial cells is inhibited by activation of antioxidant enzymes by paracrine factors secreted by human placental multipotent mesenchymal stromal cells (hPMSC). hPMSC-conditioned medium and umbilical endothelial cells were assayed for cytokines and cytokine receptor expression by immunoassay and real-time PCR. Endothelial cell survival was evaluated by MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt] assay and caspase 3 activity assay. tert-Butyl hydroperoxide was used to induce oxidative injury in endothelial cells, with fluorescent microscopy and flow cytometry used to detect intracellular peroxides and cell apoptosis. Western blot, real-time PCR, STAT3 DNA-binding activity assay, and STAT3 siRNA were used to assess endothelial cell antioxidant enzymes. hPMSC-conditioned medium supported endothelial cell survival and reduced endothelial cell intracellular peroxides and apoptosis. hPMSCs expressed the transcripts of the interleukin (IL) 6 cytokine family, including IL6 and leukemia-inhibitory factor. hPMSC-conditioned medium activated STAT3 expression in endothelial cells, which was inhibited by neutralizing antibody to interleukin 6 signal transducer (IL6ST) but not to IL6 or leukemia-inhibitory factor. STAT3 siRNA or manganese superoxide dismutase (SOD2) siRNA transfected into endothelial cells inhibited the antiapoptotic effect of conditioned medium. SOD2 was significantly upregulated in endothelial cells by conditioned medium via STAT3 activation that, in turn, was inhibited by IL6ST-neutralizing antibody or STAT3 siRNA. Paracrine factors secreted by hPMSCs support endothelial cell survival. STAT3 activation and SOD2 production protect against oxidative stress-induced endothelial cell damage.
- Published
- 2010
- Full Text
- View/download PDF
214. Safe and targeted anticancer efficacy of a novel class of antioxidant-conjugated difluorodiarylidenyl piperidones: differential cytotoxicity in healthy and cancer cells.
- Author
-
Selvendiran K, Ahmed S, Dayton A, Kuppusamy ML, Tazi M, Bratasz A, Tong L, Rivera BK, Kálai T, Hideg K, and Kuppusamy P
- Subjects
- Apoptosis drug effects, Blotting, Western, Cell Line, Tumor, Cell Survival drug effects, Electron Spin Resonance Spectroscopy, Humans, Reactive Oxygen Species metabolism, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Antineoplastic Agents pharmacology, Antioxidants pharmacology, Cell Proliferation drug effects, Piperidones pharmacology, Signal Transduction drug effects
- Abstract
The development of smart anticancer drugs that can selectively kill cancer cells while sparing the surrounding healthy tissues/cells is of paramount importance for safe and effective cancer therapy. We report a novel class of bifunctional compounds based on diarylidenyl piperidone (DAP) conjugated to an N-hydroxypyrroline (NOH; a nitroxide precursor) group. We hypothesized that the DAP would have cytotoxic (anticancer) activity, whereas the NOH moiety would function as a tissue-specific modulator (antioxidant) of cytotoxicity. The study used four DAPs, namely H-4073 and H-4318 without NOH and HO-3867 and HO-4200 with NOH substitution. The goal of the study was to evaluate the proof-of-concept anticancer-versus-antioxidant efficacy of the DAPs using a number of cancerous (breast, colon, head and neck, liver, lung, ovarian, and prostate cancer) and noncancerous (smooth muscle, aortic endothelial, and ovarian surface epithelial) human cell lines. Cytotoxicity was determined using an MTT-based cell viability assay. All four compounds induced significant loss of cell viability in cancer cells, whereas HO-3867 and HO-4200 showed significantly less cytotoxicity in noncancerous cells. EPR measurements showed a metabolic conversion of the N-hydroxylamine function to nitroxide with significantly higher levels of the metabolite and superoxide radical-scavenging (antioxidant) activity in noncancerous cells compared to cancer cells. Western blot analysis showed that the DAP-induced growth arrest and apoptosis in cancer cells were mediated by inhibition of STAT3 phosphorylation at the Tyr705 and Ser727 residues and induction of apoptotic markers of cleaved caspase-3 and PARP. The results suggest that the antioxidant-conjugated DAPs will be useful as safe and effective anticancer agents for cancer therapy., ((c) 2010 Elsevier Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
215. Sorafenib downregulates ERK/Akt and STAT3 survival pathways and induces apoptosis in a human neuroblastoma cell line.
- Author
-
Chai H, Luo AZ, Weerasinghe P, and Brown RE
- Subjects
- Antineoplastic Agents pharmacology, Blotting, Western, Cell Line, Tumor, Cell Survival drug effects, Down-Regulation drug effects, Extracellular Signal-Regulated MAP Kinases drug effects, Extracellular Signal-Regulated MAP Kinases metabolism, Humans, In Situ Nick-End Labeling, Niacinamide analogs & derivatives, Oncogene Protein v-akt drug effects, Oncogene Protein v-akt metabolism, Phenylurea Compounds, Phosphorylation drug effects, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Sorafenib, Apoptosis drug effects, Benzenesulfonates pharmacology, Neuroblastoma metabolism, Pyridines pharmacology, Signal Transduction drug effects
- Abstract
Neuroblastoma is a common solid tumor in children and its tumorigenicity is enhanced by the expression of survival pathways such as Akt and signal transducer and activator of transcription 3 (STAT3). Sorafenib is a multikinase inhibitor that also inhibits STAT3 signaling and induces apoptosis. In this study, we will examine the efficacy of sorafenib on a human neuroblastoma cell line (SK-N-AS) and also investigate its possible mechanisms. After cells reached 50-60% confluence, they were treated with various concentrations of sorafenib (0, 0.1, 1, 5, 10 and 20 microM) for different periods of time. The cell viability and apoptosis were determined by MTS colorimetric assay and TUNEL, respectively. Phosphorylation of Akt1/2/3 (p-Akt1/2/3), extracellular signal-regulated kinase 1/2 (p-ERK1/2), STAT3 (p-STAT3), and AMP-activated protein kinase alpha subunit (p-AMPKalpha) were determined with Western blot. The results indicate that as early as 2 hours post-treatment, cell viability was significantly decreased at 10 microM concentration. In 24 hours or longer treatment groups, sorafenib at 5 microM and above significantly decreased cell viability. TUNEL assay showed a significant increased of apoptosis in 5 and 20 microM treatment groups 24 hours after treatment. Western blots showed a decrease of p-ERK1/2, p-Akt1/2/3, p-STAT3, and p-AMPKalpha expression levels in various sorafenib treatment groups. Our results indicate that sorafenib significantly decreased cell viability and increased apoptosis in human neuroblastoma cell line in association with down-regulation of p-ERK1/2, p-Akt, p-STAT3 survival pathways. These data suggested potential clinical application of sorafenib in the treatment of neuroblastoma.
- Published
- 2010
216. Dexamethasone treatment inhibits VEGF production via suppression of STAT3 in a head and neck cancer cell line.
- Author
-
Shim SH, Hah JH, Hwang SY, Heo DS, and Sung MW
- Subjects
- Blotting, Western, Cell Line, Tumor, Enzyme-Linked Immunosorbent Assay, Gene Expression drug effects, Gene Expression genetics, Gene Expression Regulation, Neoplastic drug effects, Gene Expression Regulation, Neoplastic genetics, Head and Neck Neoplasms genetics, Humans, RNA, Small Interfering, STAT3 Transcription Factor genetics, STAT3 Transcription Factor metabolism, Signal Transduction drug effects, Signal Transduction physiology, Transfection, Vascular Endothelial Growth Factor A biosynthesis, Vascular Endothelial Growth Factor A genetics, Dexamethasone pharmacology, Glucocorticoids pharmacology, Head and Neck Neoplasms metabolism, STAT3 Transcription Factor drug effects, Vascular Endothelial Growth Factor A drug effects
- Abstract
Glucocorticoids (GCs) modulate the synthesis of many pro-inflammatory cytokines and influence multiple transduction pathways. GCs negatively or positively influence the transcription factors of their target genes. All of these transcription signals are closely connected to cancer survival or death. We investigated the action of dexamethasone (DEX) on head and neck cancer cell lines. When SNU-1041 and SNU-1076 were treated with DEX, the cell lines showed different patterns of responses. DEX inhibition of cell growth depended on concentration in SNU-1041, but not in SNU-1076. Furthermore, DEX suppressed vascular endothelial growth factor (VEGF) secretion from SNU-1041, but not from SNU-1076. We explored the mechanism that explains these distinct differences. After DEX treatment, the differences of NF-kappaB (p65), glucocorticoid receptor and p-AKT were not observed between the cell lines. However, phospho-signal transducer and activator of transcription 3 (STAT3) decreased in SNU-1041 only. Moreover, STAT3 inhibition using si-RNA suppressed VEGF secretion. When STAT3 was overexpressed after DEX treatment, the level of VEGF in the culture media was restored. Taken together, we suggest that p-STAT3 can be a mediating factor which regulates VEGF secretion in the DEX treatment. Because the relationship between the three molecules DEX, STAT3 and VEGF is scarcely known, our findings clarified one of the signaling pathways of DEX, which is often used in clinical conditions.
- Published
- 2010
- Full Text
- View/download PDF
217. Sulforaphane inhibits constitutive and interleukin-6-induced activation of signal transducer and activator of transcription 3 in prostate cancer cells.
- Author
-
Hahm ER and Singh SV
- Subjects
- Animals, Apoptosis drug effects, Brassicaceae chemistry, Cell Line, Tumor, DNA Fragmentation drug effects, Enzyme Activation drug effects, Gene Expression drug effects, Gene Expression Regulation drug effects, Humans, Immunoblotting, Male, Mice, Microscopy, Fluorescence, Phosphorylation drug effects, Phytotherapy, Plant Extracts pharmacology, RNA Interference, Reverse Transcriptase Polymerase Chain Reaction, STAT3 Transcription Factor metabolism, Signal Transduction drug effects, Antineoplastic Agents pharmacology, Interleukin-6 metabolism, Isothiocyanates pharmacology, Prostatic Neoplasms metabolism, STAT3 Transcription Factor drug effects
- Abstract
D,L-sulforaphane (SFN), a synthetic analogue of broccoli-derived L-isomer, inhibits viability of human prostate cancer cells and prevents development of prostate cancer and distant site metastasis in a transgenic mouse model. However, the mechanism underlying the anticancer effect of SFN is not fully understood. We now show that SFN inhibits constitutive and interleukin-6 (IL-6)-inducible activation of signal transducer and activator of transcription 3 (STAT3), which is an oncogenic transcription factor activated in many human malignancies, including prostate cancer. Growth-suppressive concentrations of SFN (20 and 40 micromol/L) decreased constitutive (DU145 cells) and IL-6-induced (DU145 and LNCaP cells) phosphorylation of STAT3 (Tyr(705)) as well as its upstream regulator Janus-activated kinase 2 (Tyr(1007/1008)). Exposure of DU145 and LNCaP cells to SFN resulted in suppression of (a) IL-6-induced transcriptional activity of STAT3 as judged by luciferase reporter assay and (b) nuclear translocation of phospho-STAT3 as revealed by immunofluorescence microscopy. Levels of many STAT3-regulated gene products, including Bcl-2, cyclin D1, and survivin, were also reduced in SFN-treated cells. The IL-6-mediated activation of STAT3 conferred partial but marked protection against SFN-induced apoptosis as evidenced by cytoplasmic histone-associated DNA fragmentation and cleavage of poly(ADP-ribose) polymerase and procaspase-3. Furthermore, knockdown of STAT3 protein using small interfering RNA resulted in a modest yet statistically significant increase in SFN-induced apoptotic DNA fragmentation in DU145 cells. Suppression of STAT3 activation was also observed in cells treated with naturally occurring analogues of SFN. In conclusion, the present study indicates that inhibition of STAT3 partially contributes to the proapoptotic effect of SFN., ((c) 2010 AACR.)
- Published
- 2010
- Full Text
- View/download PDF
218. Deguelin suppresses cell proliferation via the inhibition of survivin expression and STAT3 phosphorylation in HTLV-1-transformed T cells.
- Author
-
Ito S, Oyake T, Murai K, and Ishida Y
- Subjects
- Apoptosis drug effects, Blotting, Western, Cell Line, Cell Transformation, Viral drug effects, Down-Regulation, Humans, Inhibitor of Apoptosis Proteins, Microtubule-Associated Proteins biosynthesis, Phosphorylation, Reverse Transcriptase Polymerase Chain Reaction, Rotenone pharmacology, STAT3 Transcription Factor metabolism, Signal Transduction drug effects, Survivin, T-Lymphocytes drug effects, T-Lymphocytes virology, Antineoplastic Agents pharmacology, Cell Proliferation drug effects, HTLV-I Infections drug therapy, Microtubule-Associated Proteins drug effects, Rotenone analogs & derivatives, STAT3 Transcription Factor drug effects
- Abstract
Adult T-cell leukemia (ATL) is an aggressive malignancy of peripheral T cells infected with human T-cell leukemia virus type 1 (HTLV-1). The prognosis of aggressive ATL patients remains poor because of its resistance to conventional chemotherapy. We examined the effect of deguelin, a naturally occurring rotenoid, on HTLV-1-transformed T-cell lines, KUT-1 and MT-2 cells. We found that deguelin suppressed cell proliferation and induced cell death in these cells. Immunoblot analysis showed the inhibition of survivin expression and signal transducers, and activators of transcription (STAT) 3 phosphorylation of both cells. We also observed the cleavage of caspase-3 and poly(ADP-ribose) polymerase (PARP) in deguelin-treated cells, indicating that deguelin induces caspase-dependent apoptosis in these cells. Furthermore, proteasome inhibitor MG132 prevented the down-regulation of survivin expression and STAT3 dephosphorylation by deguelin, suggesting that the action mechanism of deguelin involves the degradation of survivin and phosphorylated STAT3 through the ubiquitin/proteasome pathway. Our data indicate that deguelin presents a potent anti-proliferative effect in part via the down-regulation of survivin expression and STAT3 phosphorylation in HTLV-1-transformed cells. Deguelin merits further investigation as a potential chemotherapeutic agent for ATL., (Copyright (c) 2009 Elsevier Ltd. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
219. Pulmonary changes induced by trans,trans-2,4-decadienal, a component of cooking oil fumes.
- Author
-
Wang CK, Chang LW, Chang H, Yang CH, Tsai MH, Tsai HT, and Lin P
- Subjects
- Aldehydes administration & dosage, Animals, Bronchioles pathology, Bronchoalveolar Lavage Fluid, Dietary Fats, Unsaturated administration & dosage, Dietary Fats, Unsaturated adverse effects, Hyperplasia chemically induced, Instillation, Drug, Macrophages, Alveolar pathology, Male, Mice, Mice, Inbred ICR, Oxidative Stress, STAT3 Transcription Factor drug effects, Volatile Organic Compounds, Air Pollutants adverse effects, Aldehydes adverse effects, Bronchioles drug effects, Macrophages, Alveolar drug effects, Respiratory Mucosa drug effects
- Abstract
Cooking oil fumes (COF) are known to be associated with respiratory diseases and risk of lung cancer. Involvement of trans,trans-2,4-decadienal (tt-DDE), a major component in COF, is suspected. Male CD-1(R) (ICR) mice were intratracheally instilled with either 8 or 24 mg.kg(-1) tt-DDE weekly for 8 weeks. Total numbers and types of cells in bronchoalveolar lavage fluid (BALF), as well as pathological changes, and inflammatory gene modulations in the lung tissues were assessed. We demonstrated that the number of alveolar macrophages in the BALF was significantly increased in tt-DDE-exposed animals. Histologically, there was a dose-correlated increase in epithelial hyperplasia and granulomatous nodules at the bronchioloalveolar junctions (BAJ). Although both Clara and alveolar type II cells were present in the BAJ lesion, only Clara cells were actively proliferative. However, only alveolar type II cells were found in the BAJ granulomatous nodules. Enhanced accumulation of phosphorylated signal transducer and activator of transcription 3 (pSTAT3), a known pro-carcinogenic factor, was also detected in many alveolar type II cells at the BAJ lesions. As both BAJ hyperplasia and enhanced pSTAT3 accumulation are known risk factors associated with increased lung adenocarcinoma development, these findings suggest that tt-DDE may pose a risk in lung carcinogenesis.
- Published
- 2010
- Full Text
- View/download PDF
220. Leukemia inhibitory factor promotes Hsp90 association with STAT3 in mouse embryonic stem cells.
- Author
-
Setati MM, Prinsloo E, Longshaw VM, Murray PA, Edgar DH, and Blatch GL
- Subjects
- Animals, Blotting, Western, Cells, Cultured, Down-Regulation, Fluorescent Antibody Technique, HSP90 Heat-Shock Proteins drug effects, Homeodomain Proteins metabolism, Mice, Nanog Homeobox Protein, STAT3 Transcription Factor drug effects, Signal Transduction, Embryonic Stem Cells metabolism, HSP90 Heat-Shock Proteins metabolism, Leukemia Inhibitory Factor pharmacology, Models, Biological, STAT3 Transcription Factor metabolism
- Abstract
Self-renewal of in vitro cultured mouse embryonic stem (mES) cells is dependent on the presence of leukemia inhibitory factor (LIF). LIF induces overexpression and tyrosine phosphorylation of STAT3 (signal transducer and activator of transcription 3) and its subsequent nuclear translocation. The molecular chaperone heat shock protein 90 (Hsp90) is involved in the activation and maturation of a wide variety of substrate proteins. We investigated the effect of LIF withdrawal on the protein expression levels of STAT3 and Hsp90 and on the interactions between STAT3 and Hsp90. Taken together the data presented here suggest that LIF promotes the interaction of Hsp90 with STAT3 during self-renewal, indicating a potentially pivotal role for Hsp90 in the LIF-based maintenance of self-renewal of mouse embryonic stem cells.
- Published
- 2010
- Full Text
- View/download PDF
221. Cholinergic agonists regulate JAK2/STAT3 signaling to suppress endothelial cell activation.
- Author
-
Chatterjee PK, Al-Abed Y, Sherry B, and Metz CN
- Subjects
- Benzylidene Compounds pharmacology, Blotting, Western, Cells, Cultured, Chemokine CCL2 drug effects, Chemokine CCL2 metabolism, Endothelial Cells drug effects, Humans, Intercellular Adhesion Molecule-1 drug effects, Intercellular Adhesion Molecule-1 metabolism, Interleukin-6 metabolism, Janus Kinase 2 drug effects, Nicotine pharmacology, Phosphorylation drug effects, Pyridines pharmacology, STAT3 Transcription Factor drug effects, Signal Transduction drug effects, Suppressor of Cytokine Signaling 3 Protein, Suppressor of Cytokine Signaling Proteins drug effects, Suppressor of Cytokine Signaling Proteins metabolism, Endothelial Cells metabolism, Janus Kinase 2 metabolism, Nicotinic Agonists pharmacology, STAT3 Transcription Factor metabolism, Signal Transduction physiology
- Abstract
The cholinergic anti-inflammatory pathway is a physiological mechanism that inhibits cytokine production and minimizes tissue injury during inflammation. Previous investigations revealed that cholinergic stimulation (via cholinergic agonists and vagus nerve stimulation) suppresses endothelial cell activation and leukocyte recruitment. The purpose of this study was to investigate the mechanisms by which cholinergic agonists (e.g., nicotine and GTS-21) regulate endothelial cell activation. Specifically, we examined the effects of cholinergic agonists on IL-6-mediated endothelial cell activation through the JAK2/STAT3 signaling pathway. Treatment of macrovascular human umbilical vein endothelial cells (HUVECs) and microvascular endothelial cells (MVECs) with the cholinergic agonists nicotine and GTS-21 significantly reduced IL-6-mediated monocyte chemoattractant protein-1 (MCP-1) production and ICAM-1 expression which are regulated through the JAK2/STAT3 pathway. We found that treatment of endothelial cells with cholinergic agonists significantly reduced STAT3 activation by phosphorylation and DNA binding. The inhibition of STAT3 phosphorylation was reversed by sodium orthovanadate, an inhibitor of tyrosine phosphatases, as well as by NSC-87877 suggesting a SHP1/2-dependent mechanism. Further investigations showed that cholinergic agonists reduced the phosphorylation of JAK2, an upstream component of the JAK2/STAT3 pathway. Finally, we observed that nicotine and GTS-21 treatment decreased levels of SOCS3 (suppressor of cytokine signaling; a regulator of the inflammatory activity of IL-6) in activated endothelial cells. These data demonstrate that cholinergic agonists suppress IL-6-mediated endothelial cell activation through the JAK2/STAT3 pathway. Our results have significant implications for better understanding the therapeutic potential of cholinergic agonists for treating IL-6 mediated inflammatory conditions.
- Published
- 2009
- Full Text
- View/download PDF
222. IFN-beta inhibits human Th17 cell differentiation.
- Author
-
Ramgolam VS, Sha Y, Jin J, Zhang X, and Markovic-Plese S
- Subjects
- CD4-Positive T-Lymphocytes drug effects, CD4-Positive T-Lymphocytes immunology, Cell Differentiation immunology, Cells, Cultured, Dendritic Cells immunology, Down-Regulation drug effects, Down-Regulation immunology, Humans, Interferon beta-1a, Interleukin-10 agonists, Interleukin-10 immunology, Interleukin-10 metabolism, Interleukin-12 Subunit p35 agonists, Interleukin-12 Subunit p35 immunology, Interleukin-12 Subunit p35 metabolism, Interleukin-1beta antagonists & inhibitors, Interleukin-1beta immunology, Interleukin-1beta metabolism, Interleukin-23 Subunit p19 antagonists & inhibitors, Interleukin-23 Subunit p19 immunology, Interleukin-23 Subunit p19 metabolism, Nuclear Receptor Subfamily 1, Group F, Member 3, Phosphorylation drug effects, Phosphorylation immunology, Receptors, CCR6 antagonists & inhibitors, Receptors, CCR6 immunology, Receptors, CCR6 metabolism, Receptors, Interleukin antagonists & inhibitors, Receptors, Interleukin immunology, Receptors, Interleukin metabolism, Receptors, Retinoic Acid immunology, Receptors, Retinoic Acid metabolism, Receptors, Thyroid Hormone immunology, Receptors, Thyroid Hormone metabolism, STAT1 Transcription Factor drug effects, STAT1 Transcription Factor immunology, STAT1 Transcription Factor metabolism, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor immunology, STAT3 Transcription Factor metabolism, T-Lymphocytes, Helper-Inducer immunology, Up-Regulation drug effects, Up-Regulation immunology, Cell Differentiation drug effects, Dendritic Cells drug effects, Interferon-beta pharmacology, Interleukin-17 immunology, Multiple Sclerosis immunology, T-Lymphocytes, Helper-Inducer drug effects
- Abstract
IFN-beta-1a has been used over the past 15 years as a primary therapy for relapsing-remitting multiple sclerosis (MS). However, the immunomodulatory mechanisms that provide a therapeutic effect against this CNS inflammatory disease are not yet completely elucidated. The effect of IFN-beta-1a on Th17 cells, which play a critical role in the development of the autoimmune response, has not been extensively studied in humans. We have investigated the effect of IFN-beta-1a on dendritic cells (DCs) and naive CD4(+)CD45RA(+) T cells derived from untreated MS patients and healthy controls in the context of Th17 cell differentiation. We report that IFN-beta-1a treatment down-regulated the expression of IL-1beta and IL-23p19 in DCs, whereas it induced the gene expression of IL-12p35 and IL-27p28. We propose that IFN-beta-1a-mediated up-regulation of the suppressor of cytokine signaling 3 expression, induced via STAT3 phosphorylation, mediates IL-1beta and IL-23 down-regulation, while IFN-beta-1a-induced STAT1 phosphorylation induces IL-27p28 expression. CD4(+)CD45RA(+) naive T cells cocultured with supernatants from IFN-beta-1a-treated DCs exhibited decreased gene expression of the Th17 cell markers retinoic acid-related orphan nuclear hormone receptor c (RORc), IL-17A, and IL-23R. A direct IFN-beta-1a treatment of CD45RA(+) T cells cultured in Th17-polarizing conditions also down-regulated RORc, IL-17A, and IL-23R, but up-regulated IL-10 gene expression. Studies of the mechanisms involved in the Th17 cell differentiation suggest that IFN-beta-1a inhibits IL-17 and induces IL-10 secretion via activated STAT1 and STAT3, respectively. IFN-beta's suppression of Th17 cell differentiation may represent its most relevant mechanism of selective suppression of the autoimmune response in MS.
- Published
- 2009
- Full Text
- View/download PDF
223. Green tea catechins inhibit angiogenesis through suppression of STAT3 activation.
- Author
-
Leong H, Mathur PS, and Greene GL
- Subjects
- Breast Neoplasms genetics, Cell Line, Tumor, Cell Movement drug effects, Endothelial Cells drug effects, Endothelial Cells metabolism, Enzyme Activation, Enzyme-Linked Immunosorbent Assay, Female, Gene Expression drug effects, Gene Expression Regulation, Humans, Immunohistochemistry, Immunoprecipitation, Interferon-gamma drug effects, Interferon-gamma metabolism, Matrix Metalloproteinase 9 biosynthesis, Matrix Metalloproteinase 9 drug effects, Neovascularization, Pathologic genetics, Reverse Transcriptase Polymerase Chain Reaction, STAT3 Transcription Factor metabolism, Transfection, Vascular Endothelial Growth Factor A biosynthesis, Vascular Endothelial Growth Factor A drug effects, Breast Neoplasms metabolism, Catechin analogs & derivatives, Catechin pharmacology, Neovascularization, Pathologic metabolism, STAT3 Transcription Factor drug effects, Tea chemistry
- Abstract
Previous studies indicate that green tea extract may inhibit breast cancer progression by blocking angiogenesis, although the molecular mechanisms are not well defined. We demonstrate that administration of Polyphenon E (Poly E), a standardized green tea extract, inhibited MDA-MB231 breast cancer and human dermal microvascular endothelial (HMVEC) cell migration and the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinase 9 (MMP9). In addition, Poly E inhibited VEGF-induced neovascularization in vivo. We also demonstrate that Poly E blocked signal transducers and activators of transcription (STAT) signaling by suppressing interferon-gamma (IFN-gamma)-induced gene transcription via IFN-gamma-activating sequence (GAS) elements and downstream STAT3 activation by inhibiting STAT1 and STAT3 dimerization in MDA-MB231 cells. Transient expression of constitutively active STAT3 significantly reduced the inhibitory effect of Poly E on cell migration and VEGF and MMP9 expression. Taken together, these observations indicate that green tea extract inhibits angiogenesis partly through the disruption of STAT3-mediated transcription of genes, including VEGF.
- Published
- 2009
- Full Text
- View/download PDF
224. All-trans retinoic acid suppresses Stat3 signaling during skin carcinogenesis.
- Author
-
Syed Z, Cheepala SB, Gill JN, Stein J, Nathan C, Digiovanni J, Batra V, Adegboyega P, Kleiner HE, and Clifford JL
- Subjects
- Animals, Blotting, Western, Carcinoma, Squamous Cell chemically induced, Cell Transformation, Neoplastic drug effects, Cell Transformation, Neoplastic metabolism, Extracellular Signal-Regulated MAP Kinases metabolism, Female, Immunohistochemistry, MAP Kinase Kinase Kinases metabolism, Mice, Mice, Inbred SENCAR, Mice, Transgenic, Skin Neoplasms chemically induced, raf Kinases metabolism, Antineoplastic Agents pharmacology, Carcinogens toxicity, Carcinoma, Squamous Cell metabolism, STAT3 Transcription Factor drug effects, Signal Transduction drug effects, Skin Neoplasms metabolism, Tetradecanoylphorbol Acetate toxicity, Tretinoin pharmacology
- Abstract
Squamous cell carcinoma (SCC) of the skin is the most clinically aggressive form of nonmelanoma skin cancer. We have determined the effects of all-trans retinoic acid (ATRA), a naturally occurring chemopreventive retinoid, on signal transducer and activator of transcription 3 (Stat3) signaling during the development of skin SCC. Stat3 is a transcription factor that plays a critical role in cell proliferation and survival, and it is constitutively active in several malignant cell types. We have previously shown that Stat3 is required for the initiation, promotion, and progression of skin SCC. ATRA is a highly efficient suppressor of tumor formation in the two-stage mouse skin carcinogenesis model and we have shown that this effect correlates with the suppression of the B-Raf/Mek/Erk signaling pathway. In this study, we have determined the pattern of Stat3 phosphorylation throughout the course of the two-stage protocol, both in the presence and absence of ATRA. We have used both SENCAR mice and K5.Stat3C transgenic mice, which express the Stat3C protein, a constitutively active form of Stat3, in the skin. Using Western blotting and immunohistochemical staining with phosphospecific antibodies, we show that coadministration of ATRA suppressed the 12-O-tetradecanoylphorbol-13-acetate-induced phosphorylation of Stat3 in both models, but was only able to suppress tumor formation in the SENCAR mice. Surprisingly, ATRA actually enhanced tumor formation in 12-O-tetradecanoylphorbol-13-acetate-treated K5.Stat3C mice. We hypothesize that ATRA blocks tumor formation, at least in part, by targeting events upstream of Stat3, such as the B-Raf/Mek/Erk pathway, and that in the K5.Stat3C mice, in which Stat3 activity is constitutive, it cannot suppress tumor formation.
- Published
- 2009
- Full Text
- View/download PDF
225. CD40 and OX40 ligand are differentially regulated on asthmatic airway smooth muscle.
- Author
-
Krimmer DI, Loseli M, Hughes JM, Oliver BG, Moir LM, Hunt NH, Black JL, and Burgess JK
- Subjects
- Adult, Aged, Asthma metabolism, CD40 Antigens agonists, CD40 Antigens immunology, Drug Synergism, Enzyme Inhibitors pharmacology, Extracellular Signal-Regulated MAP Kinases drug effects, Extracellular Signal-Regulated MAP Kinases immunology, Extracellular Signal-Regulated MAP Kinases metabolism, Humans, MAP Kinase Kinase 4 drug effects, MAP Kinase Kinase 4 immunology, MAP Kinase Kinase 4 metabolism, Middle Aged, Myocytes, Smooth Muscle immunology, NF-kappa B drug effects, NF-kappa B immunology, NF-kappa B metabolism, OX40 Ligand antagonists & inhibitors, OX40 Ligand immunology, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor immunology, STAT3 Transcription Factor metabolism, Signal Transduction drug effects, Signal Transduction immunology, Asthma immunology, CD40 Antigens metabolism, Interferon-gamma pharmacology, Myocytes, Smooth Muscle drug effects, OX40 Ligand metabolism, Tumor Necrosis Factor-alpha pharmacology
- Abstract
Background: CD40 and OX40 Ligand (OX40L) are cell-surface molecules expressed on airway smooth muscle (ASM) that can enhance inflammatory cell activation and survival. The aim of this study was to examine the effect of tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) on ASM CD40 and OX40L expression., Methods: CD40 and OX40L expression on human ASM cells from asthmatic and nonasthmatic donors following stimulation with TNF-alpha and/or IFN-gamma was measured using cell-surface enzyme-linked immunosorbent assay (ELISA) and flow cytometry. Involvement of signalling pathway was investigated with pharmacological inhibitors. Soluble TNF receptor levels were quantified by ELISA., Results: Interferon-gamma and TNF-alpha synergistically increased CD40 expression to a greater extent on asthmatic than on nonasthmatic ASM. In contrast, IFN-gamma reduced TNF-alpha-induced OX40L expression to a similar extent in both cell types. TNF-alpha and IFN-gamma induced CD40 via nuclear factor-kappaB (NF-kappaB) and signal transducer and activator of transcription-3 in both cell types and modulated OX40L via NF-kappaB and c-Jun N terminal kinase in nonasthmatic cells. Similar effects on the induction of OX40L in asthmatic cells were seen with NF-kappaB, but these were not statistically significant. The reduced OX40L expression with TNF-alpha and IFN-gamma involved extracellular regulated kinase 1/2 activation., Conclusion: Asthmatic ASM may modulate airway inflammation locally by increasing CD40 and OX40L expression in response to cytokines. IFN-gamma may regulate ASM pro-inflammatory actions by differentially modulating ASM CD40 and OX40L expression.
- Published
- 2009
- Full Text
- View/download PDF
226. Melanocortin potentiates leptin-induced STAT3 signaling via MAPK pathway.
- Author
-
Zhang Y, Wu X, He Y, Kastin AJ, Hsuchou H, Rosenblum CI, and Pan W
- Subjects
- Animals, Cell Line, Cerebral Arteries drug effects, Cyclic AMP metabolism, Enzyme Inhibitors pharmacology, Feeding Behavior drug effects, Feeding Behavior physiology, Gene Expression Regulation drug effects, Gene Expression Regulation genetics, Humans, Leptin pharmacology, MAP Kinase Signaling System drug effects, Melanocortins pharmacology, Mice, Mice, Inbred C57BL, Microcirculation drug effects, Microcirculation physiology, Receptor Cross-Talk drug effects, Receptor Cross-Talk physiology, Receptor, Melanocortin, Type 3 agonists, Receptor, Melanocortin, Type 3 genetics, Receptor, Melanocortin, Type 3 metabolism, Receptor, Melanocortin, Type 4 agonists, Receptor, Melanocortin, Type 4 genetics, Receptor, Melanocortin, Type 4 metabolism, Receptors, G-Protein-Coupled drug effects, Receptors, G-Protein-Coupled metabolism, Receptors, Leptin drug effects, Receptors, Leptin genetics, STAT3 Transcription Factor drug effects, Signal Transduction drug effects, Signal Transduction physiology, alpha-MSH metabolism, alpha-MSH pharmacology, Cerebral Arteries metabolism, Leptin metabolism, MAP Kinase Signaling System physiology, Melanocortins metabolism, Receptors, Leptin metabolism, STAT3 Transcription Factor metabolism
- Abstract
The co-existence of receptors for leptin and melanocortin in cerebral microvessels suggests possible interactions between leptin and alpha-melanocyte stimulating hormone (MSH) signaling. In this study, we showed that ObRb and melanocortin receptor MC3R and MC4R were present in enriched cerebral microvessels. To test the interactions between ObRb and MC3R or MC4R-mediated cellular signaling, we over-expressed these plasmids in RBE4 cerebral microvascular endothelial cells and HEK293 cells in culture. Activation of signal transducers and activators of transcription-3 (STAT3) in response to leptin was determined by western blotting and luciferase reporter assays. Production of cAMP downstream to melanocortin receptors was determined with a chemiluminescent ELISA kit. alphaMSH, which increased intracellular cAMP, also potentiated leptin-induced STAT3 activation. This potentiation was abolished by a specific MEK inhibitor, indicating the involvement of the mitogen-activated kinase pathway. Reversely, the effect of leptin on alphaMSH-induced cAMP production was minimal. Thus, melanocortin specifically potentiated STAT3 signaling downstream to ObRb by cross-talk with mitogen-activated kinase. The cooperation of ObRb and G protein-coupled receptors in cellular signaling may have considerable biological implications not restricted to feeding and obesity.
- Published
- 2009
- Full Text
- View/download PDF
227. Mechanisms of interleukin-1beta-induced GDNF release from rat glioma cells.
- Author
-
Tanabe K, Nishimura K, Dohi S, and Kozawa O
- Subjects
- Animals, Astrocytes drug effects, Blotting, Western, Cell Line, Tumor, Enzyme Inhibitors pharmacology, Enzyme-Linked Immunosorbent Assay, Glial Cell Line-Derived Neurotrophic Factor drug effects, I-kappa B Proteins drug effects, I-kappa B Proteins metabolism, Interleukin-1beta pharmacology, Mitogen-Activated Protein Kinase 3 drug effects, Mitogen-Activated Protein Kinase 3 metabolism, NF-kappa B drug effects, NF-kappa B metabolism, Rats, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Signal Transduction drug effects, p38 Mitogen-Activated Protein Kinases drug effects, p38 Mitogen-Activated Protein Kinases metabolism, Astrocytes metabolism, Glial Cell Line-Derived Neurotrophic Factor metabolism, Glioma metabolism, Interleukin-1beta metabolism, Signal Transduction physiology
- Abstract
Glial cell line-derived neurotrophic factor (GDNF) is highly expressed both in neurons and astrocytes in injured tissues. Astrocytes support neurons by releasing neurotrophic factors including GDNF. It has been reported that various agents including cytokines such as interleukin (IL)-1beta induce GDNF mRNA expression and the release in astrocytes. However, the mechanism behind the GDNF synthesis and release remains unclear. Herein, we investigated the mechanisms of the IL-1beta-induced GDNF release from rat C6 glioma cells. IL-1beta time dependently stimulated GDNF release from C6 cells. IL-1beta induced the phosphorylation of inhibitor kappa B (IkappaB), p38 mitogen-activated protein (MAP) kinase, p44/p42 MAP kinase, stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) and signal transducer and activator of transcription (STAT) 3. The IL-1beta-stimulated levels of GDNF were suppressed by wedelolactone, an inhibitor of IkappaB kinase, SB203580, an inhibitor of p38 MAP kinase, PD98059, an inhibitor of MAP kinase kinase 1/2 or Janus family of tyrosine kinase (JAK) inhibitor I, an inhibitor of upstream kinase of STAT3. On the contrary, SP600125, an inhibitor of SAPK/JNK, failed to reduce the IL-1beta-effect. These results strongly suggest that IL-1beta stimulates GDNF release through the pathways of IkappaB-nuclear factor kappa B, p38 MAP kinase, p44/p42 MAP kinase and JAK-STAT3, but not through the SAPK/JNK pathway in glioma cells.
- Published
- 2009
- Full Text
- View/download PDF
228. The oncogenic effects of constitutive Stat3 signaling in salivary gland cancer cells are mediated by survivin and modulated by the NSAID sulindac.
- Author
-
Nikitakis NG, Scheper MA, Papanikolaou VS, and Sauk JJ
- Subjects
- Adenocarcinoma drug therapy, Anti-Inflammatory Agents, Non-Steroidal pharmacology, Apoptosis drug effects, Apoptosis physiology, Cell Line, Tumor, Cell Proliferation drug effects, Gene Expression Regulation, Neoplastic drug effects, Gene Expression Regulation, Neoplastic physiology, Humans, Inhibitor of Apoptosis Proteins, Microtubule-Associated Proteins drug effects, Microtubule-Associated Proteins genetics, RNA, Messenger analysis, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor genetics, Salivary Gland Neoplasms drug therapy, Signal Transduction drug effects, Signal Transduction physiology, Sulindac pharmacology, Survivin, Adenocarcinoma metabolism, Antineoplastic Agents pharmacology, Cyclooxygenase Inhibitors pharmacology, Microtubule-Associated Proteins metabolism, STAT3 Transcription Factor metabolism, Salivary Gland Neoplasms metabolism
- Abstract
Objective: Constitutive activation of the signal transducer and activator of transcription 3 (Stat3) has been detected in various human cancers and has been linked to tumor development and progression. Oncogenic Stat3 signaling results in induction of specific target genes, among which survivin is implicated in the proliferation and survival of cancer cells. Targeting of Stat3 constitutive expression by the nonsteroidal antiinflammatory drug (NSAID) sulindac has been demonstrated to exert antineoplastic effects in oral squamous cell carcinoma cells in vitro and in vivo., Study Design: The expression and functional role of Stat3 and survivin was evaluated in 2 salivary gland adenocarcinoma cell lines (HSY and HSG). In addition, the effects of the NSAID sulindac and other cyclooxygenase (COX) inhibitors on Stat3 and survivin expression and on cell proliferation and apoptosis of HSY and HSG cells were analyzed., Results: Messenger RNA and protein expression of Stat3 and survivin was detected in HSY and HSG cell lines. Treatment of these cells with siRNA against Stat3 or survivin inhibited cell proliferation and induced apoptosis. Moreover, Stat3 siRNA treatment down-regulated the protein and mRNA expression of survivin, and survivin forced expression partially reversed the antineoplastic effects of Stat3 siRNA treatment. Treatment of HSY and HSG cells with the NSAID sulindac, but not other COX inhibitors, induced significant decreases in cell proliferation and increases in apoptosis, accompanied by down-regulation of Stat3 and survivin expression. In contrast, survivin forced expression or transfection with constitutively active Stat3 attenuated the effects of sulindac on cell growth and apoptosis., Conclusions: Taken together, these data support the importance of the constitutive Stat3 signaling for growth and survival of salivary gland cancer cells through the induction of survivin. Inhibition of the oncogenic Stat3-survivin pathway in these cells can be achieved by selective targeting techniques or treatment with the NSAID sulindac and holds promise for the treatment of salivary gland cancer.
- Published
- 2009
- Full Text
- View/download PDF
229. Radiation-induced HIF-1alpha cell survival pathway is inhibited by soy isoflavones in prostate cancer cells.
- Author
-
Singh-Gupta V, Zhang H, Banerjee S, Kong D, Raffoul JJ, Sarkar FH, and Hillman GG
- Subjects
- Blotting, Western, Cell Line, Tumor, DNA-(Apurinic or Apyrimidinic Site) Lyase drug effects, DNA-(Apurinic or Apyrimidinic Site) Lyase radiation effects, Electrophoretic Mobility Shift Assay, Fluorescent Antibody Technique, Humans, Hypoxia-Inducible Factor 1, alpha Subunit metabolism, Male, NF-kappa B drug effects, NF-kappa B radiation effects, Phosphorylation drug effects, Phosphorylation radiation effects, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor radiation effects, Glycine max chemistry, Vascular Endothelial Growth Factor A drug effects, src-Family Kinases drug effects, src-Family Kinases radiation effects, Hypoxia-Inducible Factor 1, alpha Subunit drug effects, Hypoxia-Inducible Factor 1, alpha Subunit radiation effects, Isoflavones pharmacology, Prostatic Neoplasms metabolism, Signal Transduction drug effects, Signal Transduction radiation effects
- Abstract
We previously showed that treatment of prostate cancer cells with soy isoflavones and radiation resulted in greater cell killing in vitro, and caused downregulation of NF-kappaB and APE1/Ref-1. APE1/Ref-1 functions as a redox activator of transcription factors, including NF-kappaB and HIF-1alpha. These molecules are upregulated by radiation and implicated in radioresistance of cancer cells. We extended our studies to investigate the role of HIF-1alpha survival pathway and its upstream Src and STAT3 molecules in isoflavones and radiation interaction. Radiation induced phosphorylation of Src and STAT3 leading to induction of HIF-1alpha. Genistein, daidzein or a mixture of soy isoflavones did not activate this pathway. These data were observed both in PC-3 (AR-) and C4-2B (AR+) androgen-independent cell lines. Pretreatment with isoflavones inhibited Src/STAT3/HIF-1alpha activation by radiation and nuclear translocation of HIF-1alpha. These findings correlated with decreased expression of APE1/Ref-1 and DNA binding activity of HIF-1alpha and NF-kappaB. In APE1/Ref-1 cDNA transfected cells, radiation caused a greater increase in HIF-1alpha and NF-kappaB activities but this effect was inhibited by pretreatment with soy prior to radiation. Transfection experiments indicate that APE1/Ref-1 inhibition by isoflavones impairs the radiation-induced transcription activity of NF-kappaB and HIF-1alpha. This mechanism could result in the inhibition of genes essential for tumor growth and angiogenesis, as demonstrated by inhibition of VEGF production and HUVECs tube formation. Our novel findings suggest that the increased responsiveness to radiation mediated by soy isoflavones could be due to pleiotropic effects of isoflavones blocking cell survival pathways induced by radiation including Src/STAT3/HIF-1alpha, APE1/Ref-1 and NF-kappaB.
- Published
- 2009
- Full Text
- View/download PDF
230. Hepatocyte growth factor induces delayed STAT3 phosphorylation through interleukin-6 expression.
- Author
-
Lee BS, Park M, Cha HY, and Lee JH
- Subjects
- Animals, Culture Media, Conditioned pharmacology, Enzyme Inhibitors pharmacology, Fibroblasts drug effects, Fibroblasts metabolism, Hepatocyte Growth Factor pharmacology, Hepatocytes drug effects, Hepatocytes metabolism, Interleukin-6 genetics, Mice, NIH 3T3 Cells, Phosphoinositide-3 Kinase Inhibitors, Phosphorylation drug effects, Protein Synthesis Inhibitors pharmacology, RNA, Messenger drug effects, RNA, Messenger metabolism, STAT3 Transcription Factor drug effects, Signal Transduction drug effects, Hepatocyte Growth Factor metabolism, Interleukin-6 metabolism, Phosphatidylinositol 3-Kinases metabolism, STAT3 Transcription Factor metabolism, Signal Transduction physiology
- Abstract
Met receptor tyrosine kinase mediates pleiotropic cellular responses following its activation by hepatocyte growth factor or scatter factor (HGF/SF). STAT3 was reported to be one of direct downstream molecules in HGF/SF-Met signaling. In the present study, however, we observed that Tyr705 of STAT3 was phosphorylated from 2 h or 6 h in NIH3T3 and Chang liver cells, respectively, after HGF/SF treatment. Blocking of the phosphorylation by cycloheximide or actinomycin D and the rapid STAT3 phosphorylation with the conditioned medium from HGF/SF-treated NIH3T3 cells suggested that a newly synthesized secretory protein was responsible for the delayed STAT3 phosphorylation. Among the known mediators to induce STAT3 phosphorylation, interleukin-6 (IL-6) mRNA and protein were induced by HGF/SF, and the released IL-6 was accumulated in the conditioned medium after HGF/SF treatment. Furthermore, the neutralizing IL-6 antibody abolished the STAT3 phosphorylation. Treatment with LY294002, a PI3 kinase inhibitor, but not with other signal inhibitors, resulted in the loss of delayed STAT3 phosphorylation by HGF/SF, showing the involvement of PI3 kinase pathway. Collectively, these results demonstrate that HGF/SF-Met signal cascade stimulates IL-6 production via PI3 kinase pathway, leading to STAT3 phosphorylation as a secondary effect.
- Published
- 2009
- Full Text
- View/download PDF
231. Growth inhibition and regression of lung tumors by silibinin: modulation of angiogenesis by macrophage-associated cytokines and nuclear factor-kappaB and signal transducers and activators of transcription 3.
- Author
-
Tyagi A, Singh RP, Ramasamy K, Raina K, Redente EF, Dwyer-Nield LD, Radcliffe RA, Malkinson AM, and Agarwal R
- Subjects
- Adenocarcinoma immunology, Adenocarcinoma metabolism, Animals, Apoptosis drug effects, Cell Proliferation drug effects, Cytokines drug effects, Cytokines immunology, Enzyme-Linked Immunosorbent Assay, Immunoblotting, Immunohistochemistry, In Situ Nick-End Labeling, Lung Neoplasms immunology, Lung Neoplasms metabolism, Macrophages drug effects, Macrophages immunology, Male, Mice, Microvessels drug effects, NF-kappa B drug effects, NF-kappa B immunology, Neovascularization, Pathologic immunology, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor immunology, Signal Transduction drug effects, Silybin, Silymarin pharmacology, Adenocarcinoma drug therapy, Angiogenesis Inhibitors pharmacology, Lung Neoplasms drug therapy, Neovascularization, Pathologic drug therapy
- Abstract
The latency period for lung tumor progression offers a window of opportunity for therapeutic intervention. Herein, we studied the effect of oral silibinin (742 mg/kg body weight, 5 d/wk for 10 weeks) on the growth and progression of established lung adenocarcinomas in A/J mice. Silibinin strongly decreased both tumor number and tumor size, an antitumor effect that correlates with reduced antiangiogenic activity. Silibinin reduced microvessel size (50%, P < 0.01) with no change in the number of tumor microvessels and reduced (by 30%, P < 0.05) the formation of nestin-positive microvessels in tumors. Analysis of several proteins involved in new blood vessel formation showed that silibinin decreased the tumor expression of interleukin-13 (47%) and tumor necrosis factor-alpha (47%), and increased tissue inhibitor of metalloproteinase-1 (2-fold) and tissue inhibitor of metalloproteinase-2 (7-fold) expression, without significant changes in vascular endothelial growth factor levels. Hypoxia- inducible factor-1 alpha expression and nuclear localization were also decreased by silibinin treatment. Cytokines secreted by tumor cells and tumor-associated macrophages regulate angiogenesis by activating nuclear factor-kappaB (NF-kappaB) and signal transducers and activators of transcription (STAT). Silibinin decreased the phosphorylation of p65NF-kappaB (ser276, 38%; P < 0.01) and STAT-3 (ser727, 16%; P < 0.01) in tumor cells and decreased the lung macrophage population. Angiopoietin-2 (Ang-2) and Ang-receptor tyrosine kinase (Tie-2) expression were increased by silibinin. Therapeutic efficacy of silibinin in lung tumor growth inhibition and regression by antiangiogenic mechanisms seem to be mediated by decreased tumor-associated macrophages and cytokines, inhibition of hypoxia-inducible factor-1 alpha, NF-kappaB, and STAT-3 activation, and up-regulation of the angiogenic inhibitors, Ang-2 and Tie-2.
- Published
- 2009
- Full Text
- View/download PDF
232. Central leptin regulates total ceramide content and sterol regulatory element binding protein-1C proteolytic maturation in rat white adipose tissue.
- Author
-
Bonzón-Kulichenko E, Schwudke D, Gallardo N, Moltó E, Fernández-Agulló T, Shevchenko A, and Andrés A
- Subjects
- Adipose Tissue drug effects, Animals, Body Weight, Cholesterol Esters metabolism, Energy Intake, Injections, Intraventricular, Leptin administration & dosage, Lipids physiology, Male, Phosphorylation, Rats, Rats, Wistar, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Sterol Regulatory Element Binding Protein 1 drug effects, Adipose Tissue metabolism, Ceramides metabolism, Leptin pharmacology, Sterol Regulatory Element Binding Protein 1 metabolism
- Abstract
Obesity and type 2 diabetes are associated with insulin and leptin resistance, and increased ceramide contents in target tissues. Because the adipose tissue has become a central focus in these diseases, and leptin-induced increases in insulin sensitivity may be related to effects of leptin on lipid metabolism, we investigated herein whether central leptin was able to regulate total ceramide levels and the expression of enzymes involved in ceramide metabolism in rat white adipose tissue (WAT). After 7 d central leptin treatment, the total content of ceramides was analyzed by quantitative shotgun lipidomics mass spectrometry. The effects of leptin on the expression of several enzymes of the sphingolipid metabolism, sterol regulatory element binding protein (SREBP)-1c, and insulin-induced gene 1 (INSIG-1) in this tissue were studied. Total ceramide levels were also determined after surgical WAT denervation. Central leptin infusion significantly decreased both total ceramide content and the long-chain fatty acid ceramide species in WAT. Concomitant with these results, leptin decreased the mRNA levels of enzymes involved in de novo ceramide synthesis (SPT-1, LASS2, LASS4) and ceramide production from sphingomyelin (SMPD-1/2). The mRNA levels of enzymes of ceramide degradation (Asah1/2) and utilization (sphingomyelin synthase, ceramide kinase, glycosyl-ceramide synthase, GM3 synthase) were also down-regulated. Ceramide-lowering effects of central leptin were prevented by local autonomic nervous system denervation of WAT. Finally, central leptin treatment markedly increased INSIG-1 mRNA expression and impaired SREBP-1c activation in epididymal WAT. These observations indicate that in vivo central leptin, acting through the autonomic nervous system, regulates total ceramide levels and SREBP-1c proteolytic maturation in WAT, probably contributing to improve the overall insulin sensitivity.
- Published
- 2009
- Full Text
- View/download PDF
233. The current STATe of biomarkers to predict the response to anti-angiogenic therapies.
- Author
-
Tran PT and Felsher DW
- Subjects
- Antibodies, Monoclonal therapeutic use, Antibodies, Monoclonal, Humanized, Antineoplastic Agents therapeutic use, Bevacizumab, Cell Division drug effects, Humans, Neoplasms pathology, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor physiology, Vascular Endothelial Growth Factor Receptor-2 drug effects, Angiogenesis Inhibitors therapeutic use, Neoplasms blood supply, Neoplasms drug therapy, Neovascularization, Pathologic prevention & control, Vascular Endothelial Growth Factor Receptor-2 physiology
- Published
- 2008
- Full Text
- View/download PDF
234. Imatinib mesylate inhibits CD4+ CD25+ regulatory T cell activity and enhances active immunotherapy against BCR-ABL- tumors.
- Author
-
Larmonier N, Janikashvili N, LaCasse CJ, Larmonier CB, Cantrell J, Situ E, Lundeen T, Bonnotte B, and Katsanis E
- Subjects
- Animals, Benzamides, Blotting, Western, Cancer Vaccines immunology, Cancer Vaccines therapeutic use, Cell Line, Tumor, Cell Proliferation drug effects, Combined Modality Therapy, Enzyme-Linked Immunosorbent Assay, Female, Flow Cytometry, Forkhead Transcription Factors biosynthesis, Forkhead Transcription Factors drug effects, Imatinib Mesylate, Immunohistochemistry, Leukemia, Myelogenous, Chronic, BCR-ABL Positive immunology, Mice, Mice, Inbred BALB C, Phosphorylation drug effects, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, STAT5 Transcription Factor drug effects, STAT5 Transcription Factor metabolism, T-Lymphocytes, Regulatory immunology, Antineoplastic Agents administration & dosage, Dendritic Cells transplantation, Immunotherapy, Active methods, Leukemia, Myelogenous, Chronic, BCR-ABL Positive therapy, Piperazines administration & dosage, Pyrimidines administration & dosage, T-Lymphocytes, Regulatory drug effects
- Abstract
Imatinib mesylate (Gleevec, STI571), a selective inhibitor of a restricted number of tyrosine kinases, has been effectively used for the treatment of Philadelphia chromosome-positive leukemias and gastrointestinal stromal tumors. Imatinib may also directly influence immune cells. Suppressive as well as stimulating effects of this drug on CD4(+) and CD8(+) T lymphocytes or dendritic cells have been reported. In the current study, we have investigated the influence of imatinib mesylate on CD4(+)CD25(+)FoxP3(+) regulatory T cells (Treg), a critical population of lymphocytes that contributes to peripheral tolerance. Used at concentrations achieved clinically, imatinib impaired Treg immunosuppressive function and FoxP3 expression but not production of IL-10 and TGF-beta in vitro. Imatinib significantly reduced the activation of the transcription factors STAT3 and STAT5 in Treg. Analysis of Treg TCR-induced signaling cascade indicated that imatinib inhibited phosphorylation of ZAP70 and LAT. Substantiating these observations, imatinib treatment of mice decreased Treg frequency and impaired their immunosuppressive function in vivo. Furthermore, imatinib mesylate significantly enhanced antitumor immune responses to dendritic cell-based immunization against an imatinib-resistant BCR-ABL negative lymphoma. The clinical applications of imatinib mesylate might thus be expanded with its use as a potent immunomodulatory agent targeting Treg in cancer immunotherapy.
- Published
- 2008
- Full Text
- View/download PDF
235. Avicin D selectively induces apoptosis and downregulates p-STAT-3, bcl-2, and survivin in cutaneous T-cell lymphoma cells.
- Author
-
Zhang C, Li B, Gaikwad AS, Haridas V, Xu Z, Gutterman JU, and Duvic M
- Subjects
- Aged, CD4-Positive T-Lymphocytes drug effects, CD4-Positive T-Lymphocytes metabolism, CD4-Positive T-Lymphocytes pathology, Case-Control Studies, Caspase 3 metabolism, Caspase Inhibitors, Cell Line, Tumor, Dose-Response Relationship, Drug, Down-Regulation drug effects, Enzyme Inhibitors pharmacology, Female, Humans, Inhibitor of Apoptosis Proteins, Lymphoma, T-Cell, Cutaneous pathology, Microtubule-Associated Proteins drug effects, Microtubule-Associated Proteins genetics, Middle Aged, Neoplasm Proteins drug effects, Neoplasm Proteins genetics, Proto-Oncogene Proteins c-bcl-2 drug effects, Proto-Oncogene Proteins c-bcl-2 genetics, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor genetics, Sezary Syndrome metabolism, Sezary Syndrome pathology, Skin Neoplasms pathology, Survivin, Time Factors, bcl-2-Associated X Protein genetics, bcl-2-Associated X Protein metabolism, Antineoplastic Agents, Phytogenic pharmacology, Apoptosis drug effects, Lymphoma, T-Cell, Cutaneous metabolism, Microtubule-Associated Proteins metabolism, Neoplasm Proteins metabolism, Proto-Oncogene Proteins c-bcl-2 metabolism, STAT3 Transcription Factor metabolism, Saponins pharmacology, Skin Neoplasms metabolism
- Abstract
Avicin D, a natural triterpenoid saponin, inhibits cell growth and induces apoptosis in transformed tumor cell lines in vitro and mouse skin carcinogenesis models in vivo. To investigate the anti-tumor effects of avicin D in cutaneous T-cell lymphomas (CTCL), we compared three CTCL cell lines and Sézary cells from three Sézary syndrome (SS) patients with normal CD4+ and activated CD4+ T cells from three healthy donors. Avicin D at 0.5-5 mug ml(-1) induced apoptosis in a time- and dose-dependent manner in three cell lines: MJ (-0.2 to 13% and 0.6-37%), Hut78 (2-39% and 3-53%), and HH (13-83% and 44-89%) at 24 and 48 hours, respectively. Avicin D at 0.5-5 microg ml(-1) for 48 hours caused more apoptosis in patients' Sézary cells than in healthy donors' CD4+ T cells and activated CD4+ T cells. The general caspase inhibitor Z-VAD-FMK and caspase-3 inhibitor Z-DEVD-FMK decreased avicin D-induced apoptosis in CTCL cells. Caspase-3 was activated and poly (ADP-ribose) polymerase was cleaved after avicin D treatment. Avicin D did not change the expression of signal transducer and activator of transcription-3 (STAT-3) but decreased phospho-signal transducer and activator of transcription-3 (p-STAT-3) protein levels in all three cell lines and two patients' Sézary cells. Avicin D also decreased expression of the inhibitor of apoptosis protein survivin, the anti-apoptotic protein bcl-2, but not the pro-apoptotic protein bax in these CTCL cells. In summary, avicin D selectively induced apoptosis, inhibited STAT-3 activation, and decreased apoptosis inhibitors (bcl-2 and survivin) in CTCL cell lines and SS patients' Sézary cells. Our findings underlie the therapeutic potential of avicin D in patients with SS.
- Published
- 2008
- Full Text
- View/download PDF
236. Effect of Jak2 kinase inhibition on Stat1 and Stat3 activation and apoptosis of tubular epithelial cells induced by ATP depletion/recovery.
- Author
-
Wang J, Ouyang C, Chen X, Fu B, Lu Y, and Hong Q
- Subjects
- Blotting, Western, Cells, Cultured, Enzyme Inhibitors pharmacology, Epithelial Cells drug effects, Epithelial Cells metabolism, Humans, Kidney Tubules, Proximal pathology, STAT1 Transcription Factor drug effects, STAT3 Transcription Factor drug effects, Tyrphostins pharmacology, Adenosine Triphosphate metabolism, Apoptosis drug effects, Epithelial Cells pathology, Janus Kinase 2 antagonists & inhibitors, Kidney Tubules, Proximal metabolism, STAT1 Transcription Factor metabolism, STAT3 Transcription Factor metabolism
- Abstract
Background: Apoptosis is involved in acute renal failure (ARF). Its exact mechanism still remains to be explored. The Jak-Stat pathway participates in inflammation, apoptosis and tumorigenesis. In an in vitro model of renal ischemia/reperfusion injury (IRI), we investigated the role of Jak2 kinase inhibition on signal transducer and activator of transcription 1 (Stat1) and Stat3 activations as well as apoptosis of human proximal tubular epithelial cells (HKCs) induced by adenosine triphosphate (ATP) depletion/recovery., Methods: ATP depletion of HKCs is induced by antimycin A., Results: The Jak2-specific inhibitor AG490 decreased Stat1 and Stat3 phosphorylations and promoted HKC apoptosis induced by ATP depletion/recovery., Conclusions: Our results have demonstrated that Jak2 inhibition participated in the ATP depletion-induced apoptosis of HKCs, which might be a potential target for prevention and treatment of ARF.
- Published
- 2008
237. IL-21 induces in vivo immune activation of NK cells and CD8(+) T cells in patients with metastatic melanoma and renal cell carcinoma.
- Author
-
Frederiksen KS, Lundsgaard D, Freeman JA, Hughes SD, Holm TL, Skrumsager BK, Petri A, Hansen LT, McArthur GA, Davis ID, and Skak K
- Subjects
- CD8-Positive T-Lymphocytes drug effects, CD8-Positive T-Lymphocytes immunology, Carcinoma, Renal Cell immunology, Dose-Response Relationship, Drug, Flow Cytometry, Gene Expression drug effects, Humans, Interleukins adverse effects, Kidney Neoplasms immunology, Killer Cells, Natural drug effects, Killer Cells, Natural immunology, Maximum Tolerated Dose, Melanoma immunology, Oligonucleotide Array Sequence Analysis, Phosphorylation, Recombinant Proteins administration & dosage, Reverse Transcriptase Polymerase Chain Reaction, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Skin Neoplasms immunology, T-Lymphocyte Subsets drug effects, T-Lymphocyte Subsets immunology, Carcinoma, Renal Cell drug therapy, Interleukins administration & dosage, Kidney Neoplasms drug therapy, Melanoma drug therapy, Skin Neoplasms drug therapy
- Abstract
Purpose: Human interleukin-21 (IL-21) is a class I cytokine previously reported in clinical studies on immune responsive cancers. Here we report the effects of systemic IL-21 therapy on the immune system in two phase 1 trials with this novel cytokine., Experimental Design: Recombinant IL-21 was administered by intravenous bolus injection at dose levels from 1 to 100 microg/kg using two planned treatment regimens: thrice weekly for 6 weeks (3/week); or once daily for five consecutive days followed by nine dose-free days (5 + 9). The following biomarkers were studied in peripheral blood mononuclear cells (PBMC) during treatment: phosphorylation of STAT3, alterations in the composition of leukocyte subsets, ex vivo cytotoxicity, expression of effector molecules in enriched CD8(+) T cells and CD56(+) NK cells by quantitative RT-PCR, and gene array profiling of CD8(+) T cells., Results: Effects of IL-21 were observed at all dose levels. In the 5 + 9 regimen IL-21 induced a dose dependent decrease in circulating NK cells and T cells followed by a return to baseline in resting periods. In both CD8(+) T cells and CD56(+) NK cells we found up-regulation of perforin and granzyme B mRNA. In addition, full transcriptome analysis of CD8(+) T cells displayed changes in several transcripts associated with increased cell cycle progression, cellular motility, and immune activation. Finally, cytotoxicity assays showed that IL-21 enhanced the ability of NK cells to kill sensitive targets ex vivo., Conclusions: IL-21 was biologically active at all dose levels administered with evidence of in vivo NK cell and CD8(+) T cell activation.
- Published
- 2008
- Full Text
- View/download PDF
238. Regulation of cytokine signaling components in developing rat retina correlates with transient inhibition of rod differentiation by CNTF.
- Author
-
Hertle D, Schleichert M, Steup A, Kirsch M, and Hofmann HD
- Subjects
- Animals, Ciliary Neurotrophic Factor pharmacology, Ciliary Neurotrophic Factor Receptor alpha Subunit drug effects, Down-Regulation drug effects, Leukemia Inhibitory Factor pharmacology, Rats, Rats, Sprague-Dawley, Receptors, OSM-LIF drug effects, Receptors, OSM-LIF metabolism, Retina cytology, Retina metabolism, Retinal Rod Photoreceptor Cells drug effects, Retinal Rod Photoreceptor Cells metabolism, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Signal Transduction drug effects, Cell Differentiation drug effects, Ciliary Neurotrophic Factor physiology, Ciliary Neurotrophic Factor Receptor alpha Subunit biosynthesis, Leukemia Inhibitory Factor metabolism, Retina growth & development, Retinal Rod Photoreceptor Cells cytology
- Abstract
Ciliary neurotrophic factor (CNTF) is known to inhibit the differentiation of rod photoreceptors from postmitotic precursor cells. During early postnatal development, photoreceptor precursors lose their responsiveness to CNTF. The underlying events causing this change in responsiveness are unknown. Moreover, whether rods express CNTF receptor alpha, a prerequisite for a direct response to the factor, is controversial. Since morphological studies have previously produced conflicting results, we have analyzed the expression of cytokine receptor components and potential ligands in the rat photoreceptor layer by real-time reverse transcription with the polymerase chain reaction after laser microdissection and by immunoblotting. Cytokine effects on rods were studied in explant cultures from newborn rat retina. CNTF receptor alpha (CNTFR alpha) and leukemia inhibitory factor receptor ss (LIFRss) were expressed in immature photoreceptors. Expression of the CNTF-specific alpha-subunit (but not of LIFRss) was downregulated specifically in the photoreceptor layer in parallel with the appearance of opsin-positive rods. The decrease of CNTFR alpha levels in explant cultures was closely correlated with the loss of precursor cell responsiveness to CNTF. Increasing the CNTF concentration in the culture medium led to prolonged CNTFR alpha expression and, concomitantly, to persistent inhibition of rod differentiation. Application of CNTF and LIF in vitro induced phosphorylation of STAT3. Inducibility of STAT3 activation by CNTF decreased with photoreceptor maturation, whereas the LIF effect persisted. Our results thus indicate that CNTF acts directly on photoreceptor precursors inhibiting their differentiation via activation of the JAK/STAT3 signal transduction pathway, and that this effect is temporally limited because of the downregulation of CNTFR alpha.
- Published
- 2008
- Full Text
- View/download PDF
239. Ethyl pyruvate has an anti-inflammatory effect by inhibiting ROS-dependent STAT signaling in activated microglia.
- Author
-
Kim HS, Cho IH, Kim JE, Shin YJ, Jeon JH, Kim Y, Yang YM, Lee KH, Lee JW, Lee WJ, Ye SK, and Chung MH
- Subjects
- Animals, Cell Line, Cyclooxygenase 2 biosynthesis, Cyclooxygenase 2 drug effects, Fluorescent Antibody Technique, Gene Expression drug effects, Male, Mice, Mice, Inbred C57BL, Microglia metabolism, Protein Transport drug effects, Reverse Transcriptase Polymerase Chain Reaction, STAT1 Transcription Factor drug effects, STAT3 Transcription Factor drug effects, Transcription, Genetic drug effects, Anti-Inflammatory Agents pharmacology, Microglia drug effects, Pyruvates pharmacology, Reactive Oxygen Species metabolism, STAT Transcription Factors drug effects, Signal Transduction drug effects
- Abstract
Ethyl pyruvate (EP) has been demonstrated to have an anti-inflammatory function. However, the molecular mechanisms underlying the anti-inflammatory action of EP are largely unknown. We here show that EP exerts its anti-inflammatory effect by inhibiting ROS-dependent STAT signaling through its antioxidant activity, like vitamin C or N-acetyl-L-cysteine. The inhibition of STAT1 and STAT3 by EP prevented their translocation to the nucleus and consequently inhibited expression of iNOS and COX-2 by inhibiting STAT1- and STAT3-mediated transcriptional activity, followed by changes in chromatin conformation via deacetylation of histones H3 and H4 in both gene promoters. EP also suppressed transcripts of other STAT-responsive inflammatory genes such as IL-1beta, IL-6, TNF-alpha, and MCP-1. We further found that the mechanism of inhibition of STAT1 and STAT3 by EP is due to inhibition of JAK2 through Rac1 inactivation and SOCS1 induction. These findings offer new therapeutic possibilities for EP based on a better understanding of the mechanism underlying the action of EP.
- Published
- 2008
- Full Text
- View/download PDF
240. Augmentation of radiation response by panitumumab in models of upper aerodigestive tract cancer.
- Author
-
Kruser TJ, Armstrong EA, Ghia AJ, Huang S, Wheeler DL, Radinsky R, Freeman DJ, and Harari PM
- Subjects
- Animals, Apoptosis drug effects, Carcinoma, Non-Small-Cell Lung drug therapy, Carcinoma, Squamous Cell drug therapy, Cell Line, Tumor, Combined Modality Therapy methods, DNA Damage drug effects, Drug Screening Assays, Antitumor methods, ErbB Receptors metabolism, Humans, Lung Neoplasms drug therapy, Mice, Mice, Nude, Mitogen-Activated Protein Kinases drug effects, Mouth Floor, Mouth Neoplasms drug therapy, Panitumumab, Phosphorylation drug effects, Proliferating Cell Nuclear Antigen metabolism, Radiation Tolerance drug effects, STAT3 Transcription Factor drug effects, Signal Transduction drug effects, Transplantation, Heterologous, Antibodies, Monoclonal pharmacology, Antineoplastic Agents pharmacology, Carcinoma, Non-Small-Cell Lung radiotherapy, Carcinoma, Squamous Cell radiotherapy, Lung Neoplasms radiotherapy, Mouth Neoplasms radiotherapy
- Abstract
Purpose: To examine the interaction between panitumumab, a fully human anti-epidermal growth factor receptor monoclonal antibody, and radiation in head-and-neck squamous cell carcinoma and non-small-cell lung cancer cell lines and xenografts., Methods and Materials: The head-and-neck squamous cell carcinoma lines UM-SCC1 and SCC-1483, as well as the non-small-cell lung cancer line H226, were studied. Tumor xenografts in athymic nude mice were used to assess the in vivo activity of panitumumab alone and combined with radiation. In vitro assays were performed to assess the effect of panitumumab on radiation-induced cell signaling, apoptosis, and DNA damage., Results: Panitumumab increased the radiosensitivity as measured by the clonogenic survival assay. Radiation-induced epidermal growth factor receptor phosphorylation and downstream signaling through mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) was inhibited by panitumumab. Panitumumab augmented radiation-induced DNA damage by 1.2-1.6-fold in each of the cell lines studied as assessed by residual gamma-H(2)AX foci after radiation. Radiation-induced apoptosis was increased 1.4-1.9-fold by panitumumab, as evidenced by Annexin V-fluorescein isothiocyanate staining and flow cytometry. In vivo, the combination therapy of panitumumab and radiation was superior to panitumumab or radiation alone in the H226 xenografts (p = 0.01) and showed a similar trend in the SCC-1483 xenografts (p = 0.08). In vivo, immunohistochemistry demonstrated the ability of panitumumab to augment the antiproliferative and antiangiogenic effects of radiation., Conclusion: These studies have identified a favorable interaction in the combination of radiation and panitumumab in upper aerodigestive tract tumor models, both in vitro and in vivo. These data suggest that clinical investigations examining the combination of radiation and panitumumab in the treatment of epithelial tumors warrant additional pursuit.
- Published
- 2008
- Full Text
- View/download PDF
241. T40214/PEI complex: a potent therapeutics for prostate cancer that targets STAT3 signaling.
- Author
-
Weerasinghe P, Li Y, Guan Y, Zhang R, Tweardy DJ, and Jing N
- Subjects
- Adenocarcinoma pathology, Animals, Apoptosis drug effects, Cell Line, Tumor, Cell Proliferation drug effects, Humans, Male, Membrane Potential, Mitochondrial drug effects, Mice, Mice, Nude, Neovascularization, Pathologic drug therapy, Oligodeoxyribonucleotides pharmacology, Polyethyleneimine, Prostatic Neoplasms pathology, STAT3 Transcription Factor drug effects, Xenograft Model Antitumor Assays, Adenocarcinoma drug therapy, Adenocarcinoma metabolism, Oligodeoxyribonucleotides therapeutic use, Prostatic Neoplasms drug therapy, Prostatic Neoplasms metabolism, STAT3 Transcription Factor metabolism, Signal Transduction drug effects
- Abstract
Background: Prostate cancer (PC) is the most common cancer among men in American and the second leading cause of cancer death. The treatment options employed for patients with advanced and metastatic PC are limited. As a critical mediator of oncogenic signaling, STAT3 is active in 82% of patients with PC. STAT3 has become a very important molecular target for PC therapy since it upregulates the oncogenes encoding apoptosis inhibitors, cell cycle regulators, and inducers of angiogenesis. However, no anti-tumor drug whose primary mode of action is to target STAT3 has yet reached the clinic. To this end, we have laid the initial groundwork to develop the STAT3-inhibiting G-quartet oligodeoxynucleotide (GQ-ODN), T40214, for treatment of PCs., Methods: We employed in vitro and in vivo assays, including Western blots, EMSA, cell cycle analysis, TUNEL and xenograft models, to determine the drug efficacy and mechanism of T40214/PEI complex., Results: The results demonstrated that (i) T40214 significantly inhibited STAT3 activation and induced apoptosis in both androgen-dependent and androgen-independent PC cells; (ii) T40214 delivered by ployethylenimine (PEI) significantly suppressed prostate tumor growth in tumor-bearing nude mice due to that T40214 inhibited STAT3 activation and then greatly promoted apoptosis, reduced angiogenesis and cell proliferation in prostate tumors., Conclusion: Our studies suggested that STAT3 is a critical oncogenic signal, which strongly influences the progression of PCs and that T40214/PEI complex is a promising candidate for treatment of patients with prostate tumors and represents a novel strategy for PC therapy., ((c) 2008 Wiley-Liss, Inc.)
- Published
- 2008
- Full Text
- View/download PDF
242. Acute alcohol intake induces SOCS1 and SOCS3 and inhibits cytokine-induced STAT1 and STAT3 signaling in human monocytes.
- Author
-
Norkina O, Dolganiuc A, Catalano D, Kodys K, Mandrekar P, Syed A, Efros M, and Szabo G
- Subjects
- Case-Control Studies, Central Nervous System Depressants pharmacology, Chemokine CCL2 metabolism, DNA metabolism, Dose-Response Relationship, Drug, Down-Regulation drug effects, Female, Humans, Intercellular Adhesion Molecule-1 metabolism, Interferon-alpha pharmacology, Interferon-gamma pharmacology, Interleukin-6 pharmacology, Male, Monocytes cytology, Monocytes drug effects, RNA, Messenger metabolism, STAT1 Transcription Factor drug effects, STAT3 Transcription Factor drug effects, Suppressor of Cytokine Signaling 1 Protein, Suppressor of Cytokine Signaling 3 Protein, Suppressor of Cytokine Signaling Proteins drug effects, Ethanol pharmacology, Monocytes metabolism, STAT1 Transcription Factor metabolism, STAT3 Transcription Factor metabolism, Signal Transduction drug effects, Suppressor of Cytokine Signaling Proteins metabolism
- Abstract
Background: Acute alcohol consumption is associated with induction of immuno-inhibitory cytokines and down-regulation of pro-inflammatory responses to various pathogens. We previously reported that alcohol activates janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling leading to IL-10 induction. The JAK-STAT pathway also activates its own negative regulators, suppressors of cytokine signaling (SOCS) 1 and SOCS3. SOCS proteins are inducible inhibitors that negatively regulate STAT3/STAT1 signaling pathways induced by cytokines, IL-6 or IFNs. Here we aimed to explore the effect of acute alcohol on induction of SOCS1/SOCS3 and regulation of STAT3/STAT1 pathways induced by IL-6 or IFNs in human monocytes., Methods: Blood samples from normal volunteers were collected before and 24 hours after consumption of 2 ml vodka/kg body weight. For in vitro experiments human monocytes were pretreated with ethanol (EtOH) followed by stimulation with cytokines; proteins were analyzed by Western blot, nuclear protein binding to DNA by EMSA, and RNA by real time PCR., Results: Acute in vivo or in vitro alcohol treatment increased both SOCS1 and SOCS3 RNA expression in monocytes. Alcohol treatment resulted in increased STAT3 and STAT1 DNA binding capacity. Activation of both STAT1 and STAT3 has been shown to induce SOCS1/3. We hypothesized that induction of SOCS proteins by alcohol in turn may lead to modulation of cytokine signaling through STAT1 and STAT3. Indeed, we observed significant down-regulation of IL-6-, IFNalpha- and IFNgamma-induced STAT1 DNA binding as well as inhibition of IL-6- and IFNgamma-induced STAT3 when alcohol was added to monocytes 3 hours prior to the cytokine stimulation. Consistent with inhibition of IL-6-induced STAT3 DNA binding in alcohol-pretreated cells, the levels of IL-6-dependent genes, MCP-1 and ICAM-1, was reduced after IL-6 stimulation. Similar to EtOH alone, combined EtOH+IL-6 simulation resulted in increased expression of both SOCS3 and SOCS1 genes., Conclusion: While acute alcohol treatment alone activates STAT1/3 signaling pathways and induces SOCS3 and SOCS1 levels in monocytes, alcohol also leads to down-regulation of IL-6-, IFNalpha-, and IFNgamma-induced signaling via STAT1/STAT3 pathways, likely through excessive SOCS activation.
- Published
- 2008
- Full Text
- View/download PDF
243. Nox5 mediates PDGF-induced proliferation in human aortic smooth muscle cells.
- Author
-
Jay DB, Papaharalambus CA, Seidel-Rogol B, Dikalova AE, Lassègue B, and Griendling KK
- Subjects
- Aorta drug effects, Blotting, Western, Cell Proliferation drug effects, Cells, Cultured, Enzyme Inhibitors pharmacology, Humans, Janus Kinase 2 drug effects, Janus Kinase 2 metabolism, Membrane Proteins drug effects, Myocytes, Smooth Muscle drug effects, NADPH Oxidase 5, NADPH Oxidases drug effects, Phosphorylation, Platelet-Derived Growth Factor drug effects, Protein Isoforms metabolism, Reactive Oxygen Species metabolism, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Transfection, Aorta metabolism, Membrane Proteins metabolism, Muscle, Smooth, Vascular metabolism, Myocytes, Smooth Muscle metabolism, NADPH Oxidases metabolism, Platelet-Derived Growth Factor metabolism
- Abstract
The proliferation of vascular smooth muscle cells is important in the pathogenesis of many vascular diseases. Reactive oxygen species (ROS) produced by NADPH oxidases in smooth muscle cells have been shown to participate in signaling cascades regulating proliferation induced by platelet-derived growth factor (PDGF), a powerful smooth muscle mitogen. We sought to determine the role of Nox5 in the regulation of PDGF-stimulated human aortic smooth muscle cell (HASMC) proliferation. Cultured HASMC were found to express four isoforms of Nox5. When HASMC stimulated with PDGF were pretreated with N-acetyl cysteine (NAC), proliferation was significantly reduced. Proliferation induced by PDGF was also heavily dependent on JAK/STAT activation, as the JAK inhibitor, AG490, was able to completely abolish PDGF-stimulated HASMC growth. Specific knockdown of Nox5 with a siRNA strategy reduced PDGF-induced HASMC ROS production and proliferation. Additionally, siRNA to Nox5 inhibited PDGF-stimulated JAK2 and STAT3 phosphorylation. ROS produced by Nox5 play an important role in PDGF-induced JAK/STAT activation and HASMC proliferation.
- Published
- 2008
- Full Text
- View/download PDF
244. STAT3 activation in photoreceptors by leukemia inhibitory factor is associated with protection from light damage.
- Author
-
Ueki Y, Wang J, Chollangi S, and Ash JD
- Subjects
- Animals, Cell Death drug effects, Cell Death physiology, Cell Nucleus drug effects, Cell Nucleus metabolism, Cytokine Receptor gp130 drug effects, Cytokine Receptor gp130 metabolism, Cytoprotection drug effects, Dose-Response Relationship, Drug, Extracellular Signal-Regulated MAP Kinases drug effects, Extracellular Signal-Regulated MAP Kinases metabolism, Leukemia Inhibitory Factor pharmacology, Male, Mice, Mice, Inbred BALB C, Neuroglia drug effects, Neuroglia metabolism, Neuroprotective Agents metabolism, Neuroprotective Agents pharmacology, Oxidative Stress drug effects, Oxidative Stress physiology, Photoreceptor Cells drug effects, STAT3 Transcription Factor drug effects, Signal Transduction drug effects, Signal Transduction physiology, Time Factors, Transcriptional Activation drug effects, Transcriptional Activation physiology, Cytoprotection physiology, Leukemia Inhibitory Factor metabolism, Light adverse effects, Photoreceptor Cells metabolism, Photoreceptor Cells radiation effects, STAT3 Transcription Factor metabolism
- Abstract
Members of the interleukin-6 cytokine family, including leukemia inhibitory factor (LIF), signal through gp130. The neuroprotective role of gp130 activation has been widely demonstrated in both CNS and PNS, but the mechanism by which this is accomplished is not well established. We investigated temporal and cell-specific activation of signaling pathways induced by LIF in the mature mouse retina. Intravitreal injection of LIF preserved photoreceptor function and prevented photoreceptor cell death from light-induced oxidative damage in a dose-dependent manner (2 days post-injection). A therapeutic dose of LIF induced rapid and sustained activation of signal transducer and activator of transcription (STAT) 3. Activated STAT3 was localized to all the retinal neurons and glial cells, including photoreceptors. Activation of extracellular signal-regulated kinase 1 and 2 was robust but transient in Müller glial cells, and undetectable at the time of light exposure. Akt was not activated by LIF. We also show that at the time of neuroprotection, STAT3 but not extracellular signal-regulated kinase 1 and 2 or the Akt pathways was active in LIF-treated retinas, and activated STAT3 was clearly localized in transcriptionally active areas of photoreceptor nuclei. Our data suggest that photoreceptor protection in response to LIF can be directly mediated by activation of STAT3 in photoreceptors.
- Published
- 2008
- Full Text
- View/download PDF
245. Müller glia factors induce survival and neuritogenesis of peripheral and central neurons.
- Author
-
de Melo Reis RA, Cabral-da-Silva Me, de Mello FG, and Taylor JS
- Subjects
- Animals, Antibodies, Blocking pharmacology, Blotting, Western, Brain-Derived Neurotrophic Factor antagonists & inhibitors, Cell Count, Cell Survival drug effects, Central Nervous System drug effects, Ciliary Neurotrophic Factor antagonists & inhibitors, Colforsin pharmacology, Culture Media, Conditioned chemistry, Extracellular Signal-Regulated MAP Kinases drug effects, Humans, Mice, Nerve Growth Factors antagonists & inhibitors, Nerve Growth Factors pharmacology, Neuroglia metabolism, Oncogene Protein v-akt drug effects, Peripheral Nerves drug effects, Rats, STAT3 Transcription Factor drug effects, Superior Cervical Ganglion cytology, Superior Cervical Ganglion drug effects, Sympathetic Nervous System cytology, Sympathetic Nervous System drug effects, Central Nervous System cytology, Culture Media, Conditioned pharmacology, Neurites drug effects, Neuroglia physiology, Neurons drug effects, Peripheral Nerves cytology
- Abstract
We have examined the trophic effects of conditioned media obtained from purified murine Müller glia cells on chick purified sympathetic or dorsal root ganglia (DRG) neurons and on Retinal Ganglion Cells (RGC) from postnatal mice. Purified murine Müller glia cultures stained positively for vimentin, GFAP or S-100, but were negative for neuronal markers. Murine Müller glial conditioned medium (MMG) was concentrated and at 1:1 dilution supported 100% survival of chick or rat sympathetic neurons after 48 h compared to <5% in controls. Partial purification of the MMG using centriprep concentrators showed that trophic activity is from molecules above 10 kDa. MMG stimulated AKT, ERK and pStat3 in sympathetic neurons. Sympathetic or DRG neuronal survival induced by MMG was blocked by anti-human NGF, but not by anti-human CNTF (sympathetic) or by anti-BDNF (DRGs) neutralizing antibodies. MMG also induced neurite outgrowth in P4 mice retinal explants and on isolated RGC. RGCs plated on top of Müller glia cells had a much better survival rate (>80%, 96 h) compared to laminin+poly-L-lysine substrates. In conclusion, we show that purified mice Müller glia cultures secrete NGF that support peripheral neuronal survival and other unidentified trophic molecules that induce RGC survival and neuritogenesis.
- Published
- 2008
- Full Text
- View/download PDF
246. Enhancement of Bovine oocyte maturation by leptin is accompanied by an upregulation in mRNA expression of leptin receptor isoforms in cumulus cells.
- Author
-
van Tol HT, van Eerdenburg FJ, Colenbrander B, and Roelen BA
- Subjects
- Animals, Cattle, Cells, Cultured, Cumulus Cells cytology, Cumulus Cells metabolism, Dose-Response Relationship, Drug, Gene Expression Regulation, Developmental drug effects, Gene Expression Regulation, Developmental genetics, Meiosis drug effects, Meiosis genetics, Mitogen-Activated Protein Kinase 1 drug effects, Mitogen-Activated Protein Kinase 1 metabolism, Mitogen-Activated Protein Kinase 3 drug effects, Mitogen-Activated Protein Kinase 3 metabolism, Oocytes metabolism, Phosphorylation drug effects, Protein Isoforms drug effects, Protein Isoforms genetics, RNA, Messenger drug effects, Receptors, Leptin drug effects, Reverse Transcriptase Polymerase Chain Reaction methods, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Structure-Activity Relationship, Up-Regulation drug effects, Up-Regulation genetics, Cumulus Cells drug effects, Leptin pharmacology, Oocytes drug effects, Oocytes growth & development, RNA, Messenger genetics, Receptors, Leptin genetics
- Abstract
In this study, the mechanisms of supposed leptin action on oocyte maturation were examined. Expression of leptin mRNA, as determined with RT-PCR, was present in oocytes but not in cumulus cells. The long isoform of the leptin receptor (ObR-L) was expressed exclusively in cumulus cells after 7 and 23 hr of maturation. In oocytes the expression of the short receptor isoform (ObR-S) and all the receptor isoforms combined (ObR-T) did not change during maturation, as determined by quantitative RT-PCR, but in cumulus cells there was a significant increase in ObR-S transcripts after 7 hr of maturation. To determine if leptin plays a role in resumption of meiosis, oocytes meiotically arrested by the connection of the cumulus to a piece of granulosa layer were exposed to leptin. After 23 hr of culture, the proportion of oocytes that had resumed meiosis did not differ from the control. Exposure of COCs to leptin (1,000 ng/ml) resulted after 17 hr of maturation in a smaller proportion of oocytes that was still in metaphase-I stage (M-I) compared to the control group. Fertilization of oocytes after maturation in the presence of leptin resulted in a larger proportion of embryos that had developed to the 8-cell stage on Day 5 compared to the control group and in more blastocysts on Day 8 of culture. It is concluded that leptin enhances meiotic maturation of bovine oocytes, and that this effect is cumulus cell-mediated., (Copyright 2007 Wiley-Liss, Inc.)
- Published
- 2008
- Full Text
- View/download PDF
247. Prevention of hypovolemic circulatory collapse by IL-6 activated Stat3.
- Author
-
Alten JA, Moran A, Tsimelzon AI, Mastrangelo MA, Hilsenbeck SG, Poli V, and Tweardy DJ
- Subjects
- Animals, Apoptosis drug effects, Disease Models, Animal, Hypovolemia, Myocytes, Cardiac pathology, Rats, Signal Transduction drug effects, Interleukin-6 therapeutic use, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Shock prevention & control
- Abstract
Half of trauma deaths are attributable to hypovolemic circulatory collapse (HCC). We established a model of HCC in rats involving minor trauma plus severe hemorrhagic shock (HS). HCC in this model was accompanied by a 50% reduction in peak acceleration of aortic blood flow and cardiomyocyte apoptosis. HCC and apoptosis increased with increasing duration of hypotension. Apoptosis required resuscitation, which provided an opportunity to intervene therapeutically. Administration of IL-6 completely reversed HCC, prevented cardiac dysfunction and cardiomyocyte apoptosis, reduced mortality 5-fold and activated intracardiac signal transducer and activator of transcription (STAT) 3. Pre-treatment of rats with a selective inhibitor of Stat3, T40214, reduced the IL-6-mediated increase in cardiac Stat3 activity, blocked successful resuscitation by IL-6 and reversed IL-6-mediated protection from cardiac apoptosis. The hearts of mice deficient in the naturally occurring dominant negative isoform of Stat3, Stat3beta, were completely resistant to HS-induced apoptosis. Microarray analysis of hearts focusing on apoptosis related genes revealed that expression of 29% of apoptosis related genes was altered in HS vs. sham rats. IL-6 treatment normalized the expression of these genes, while T40214 pretreatment prevented IL-6-mediated normalization. Thus, cardiac dysfunction, cardiomyocyte apoptosis and induction of apoptosis pathway genes are important components of HCC; IL-6 administration prevented HCC by blocking cardiomyocyte apoptosis and induction of apoptosis pathway genes via Stat3 and warrants further study as a resuscitation adjuvant for prevention of HCC and death in trauma patients.
- Published
- 2008
- Full Text
- View/download PDF
248. Role of STAT3 in CD4+CD25+FOXP3+ regulatory lymphocyte generation: implications in graft-versus-host disease and antitumor immunity.
- Author
-
Pallandre JR, Brillard E, Créhange G, Radlovic A, Remy-Martin JP, Saas P, Rohrlich PS, Pivot X, Ling X, Tiberghien P, and Borg C
- Subjects
- Animals, CD28 Antigens immunology, CD3 Complex immunology, CD4-Positive T-Lymphocytes immunology, Cell Line, Tumor, Disease Models, Animal, Forkhead Transcription Factors antagonists & inhibitors, Forkhead Transcription Factors genetics, Gene Expression Profiling, Gene Expression Regulation, Neoplastic immunology, Male, Mice, Mice, Inbred BALB C, Mice, Inbred C57BL, Neoplasm Transplantation, Phenotype, Phosphorylation, RNA, Messenger drug effects, RNA, Messenger genetics, RNA, Small Interfering pharmacology, Reverse Transcriptase Polymerase Chain Reaction, STAT3 Transcription Factor drug effects, STAT3 Transcription Factor metabolism, Signal Transduction drug effects, Signal Transduction immunology, T-Lymphocytes, Regulatory transplantation, Forkhead Transcription Factors biosynthesis, Graft vs Host Disease immunology, Immunotherapy, Adoptive methods, Neoplasms immunology, STAT3 Transcription Factor physiology, T-Lymphocytes, Regulatory immunology
- Abstract
Immunological tolerance is maintained by specialized subsets of T cells including CD4(+)CD25(+)FOXP3(+) regulatory cells (Treg). Previous studies established that Treg thymic differentiation or peripheral conversion depend on CD28 and Lck signaling. Moreover, foxp3 gene transfer in murine CD4(+)CD25(-) T lymphocytes results in the acquisition of suppressive functions. However, molecular pathways leading to FOXP3 expression remain to be described. In this study, we investigated the molecular events driving FOXP3 expression. We demonstrated that CD28 activation in CD4(+)CD25(-) T lymphocytes leads to STAT3 Tyr(705) phosphorylation in an Lck-dependent manner. STAT3 neutralization during naive peripheral CD4(+)CD25(-) T cell conversion into Treg through costimulation with TCR/CD28 and TGF-beta1, decreased FOXP3 expression, prevented the acquisition of suppressive functions and restored the ability of the converted lymphocytes to produce IL-2 and IFN-gamma. Furthermore, we observed that STAT3 ablation using small interfering RNA strategies inhibited FOXP3 expression and suppressive functions among naturally differentiated CD4(+)CD25(+) T lymphocytes, suggesting a direct role of STAT3 in Treg phenotype and function maintenance. CD4(+)CD25(+) T lymphocytes transduced with specific STAT3 small interfering RNA were devoid of suppressive functions and failed to control the occurrence of acute graft-vs-host disease. Finally, STAT3 inhibition in CD4(+) lymphocytes enhanced the anti-tumor immunity conferred by a lymphocyte adoptive transfer. In summary, our findings determine that STAT3 is critical in the molecular pathway required for FOXP3 expression. STAT3 modulation should be taken into account when assessing how regulatory T cells contribute to inflammatory diseases and tumor immunosurveillance.
- Published
- 2007
- Full Text
- View/download PDF
249. Retrograde activation of STAT3 by leukemia inhibitory factor in sympathetic neurons.
- Author
-
O'Brien JJ and Nathanson NM
- Subjects
- Active Transport, Cell Nucleus drug effects, Animals, Cell Nucleus metabolism, Cells, Cultured, Leukemia Inhibitory Factor pharmacology, Mice, Mice, Inbred C57BL, Neurites drug effects, Neurites metabolism, Neurons drug effects, STAT3 Transcription Factor drug effects, Signal Transduction drug effects, Superior Cervical Ganglion cytology, Leukemia Inhibitory Factor physiology, Neurons metabolism, STAT3 Transcription Factor metabolism, Signal Transduction physiology
- Abstract
Leukemia inhibitory factor (LIF) is a member of the interleukin-6 family of cytokines and signals through the glycoprotein 130 and LIF receptor beta subunits. Binding of cytokines to these subunits activates multiple signaling cascades, including the Janus kinase (Jak)/signal transducers and activators of transcription (STAT) pathway. We used compartmentalized cultures of sympathetic neurons and immunocytochemical analyses of STAT3 to examine the mechanisms involved in retrograde signaling of LIF from distal neurites (DN) to cell bodies. Addition of LIF to the DN of these neurons triggers the activation and nuclear translocation of STAT3. Inhibition of Jak activity in the cell bodies prevented LIF-induced retrograde activation of STAT3, while block of Jak activity in the DN had no effect on the appearance of activated STAT3 in the nucleus. These results show that the transport of activated Jak is not the main mechanism mediating retrograde signaling. Although there is an increase in phosphorylated STAT3 in the neurites after distal stimulation, the transport of activated STAT3 is not necessary for retrograde signaling. Our results are consistent with a signaling endosome model for retrograde signaling, in which the LIF/glycoprotein 130/LIF receptor/Jak complex is internalized and transported to activate STAT3 in the cell body.
- Published
- 2007
- Full Text
- View/download PDF
250. Cardioplegia and diazoxide modulate STAT3 activation and DNA binding.
- Author
-
Hsieh YJ, Wakiyama H, Levitsky S, and McCully JD
- Subjects
- Animals, Apoptosis physiology, Binding Sites, Blotting, Western, Cardioplegic Solutions, Disease Models, Animal, Electrophoresis, Female, Ischemic Preconditioning, Myocardial methods, Male, Mitochondria, Heart drug effects, Myocardial Reperfusion Injury prevention & control, Phosphorylation, Random Allocation, STAT3 Transcription Factor drug effects, Sensitivity and Specificity, Swine, Tyrosine metabolism, Apoptosis drug effects, DNA metabolism, Diazoxide pharmacology, Heart Arrest, Induced, STAT3 Transcription Factor metabolism
- Abstract
Background: Previously, we have shown that magnesium supplemented potassium (DSA) cardioplegia and DSA containing diazoxide (DSA+DZX) significantly decrease apoptosis after ischemia. The mechanism for this enhanced cardioprotection was unknown, but we believed that alterations in signal transducers and activators of transcription (STATs) may play a role. To investigate this hypothesis, we examined the effects of DSA and DSA+DZX cardioplegia on STAT1/3 phosphorylation and DNA binding in the in situ blood perfused pig heart model., Methods: Pigs (32 to 42 kg) undergoing total cardiopulmonary bypass underwent left anterior descending coronary artery occlusion for 30 minutes. The aorta was crossclamped and DSA (n = 6) or DSA+DZX (n = 6) cardioplegia was administered, followed by 30 minutes of global ischemia and 120 minutes of reperfusion. Control hearts (n = 3) received cardiopulmonary bypass and sham reperfusion only. Tissue samples from regional and global ischemia zones were harvested and used for Western blot and electrophoretic mobility shift assay., Results: Regional and global ischemia significantly increase proapoptotic STAT1 tyrosine phosphorylation. This increase is significantly greater in the regional as compared with the global ischemia zone. Tyrosine phosphorylation of antiapoptotic STAT3 is increased in the global ischemic zone but is significantly decreased in the regional ischemic zone and is associated with increased apoptosis. The DSA+DZX significantly increases tyrosine phosphorylation of antiapoptotic STAT3 and DNA binding in the regional ischemia zone and significantly decreases apoptosis., Conclusions: The addition of diazoxide to DSA cardioplegia significantly decreases apoptosis by significantly increasing tyrosine phosphorylation of STAT3 and its DNA binding and represents an additional modality for enhancing myocardial protection.
- Published
- 2007
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.