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Xiong A, Yang Z, Shen Y, Zhou J, Shen Q. Transcription Factor STAT3 as a Novel Molecular Target for Cancer Prevention. Cancers (Basel) 2014; 6:926-57. [PMID: 24743778 PMCID: PMC4074810 DOI: 10.3390/cancers6020926] [Citation(s) in RCA: 213] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 03/11/2014] [Accepted: 03/18/2014] [Indexed: 12/11/2022] Open
Abstract
Signal Transducers and Activators of Transcription (STATs) are a family of transcription factors that regulate cell proliferation, differentiation, apoptosis, immune and inflammatory responses, and angiogenesis. Cumulative evidence has established that STAT3 has a critical role in the development of multiple cancer types. Because it is constitutively activated during disease progression and metastasis in a variety of cancers, STAT3 has promise as a drug target for cancer therapeutics. Recently, STAT3 was found to have an important role in maintaining cancer stem cells in vitro and in mouse tumor models, suggesting STAT3 is integrally involved in tumor initiation, progression and maintenance. STAT3 has been traditionally considered as nontargetable or undruggable, and the lag in developing effective STAT3 inhibitors contributes to the current lack of FDA-approved STAT3 inhibitors. Recent advances in cancer biology and drug discovery efforts have shed light on targeting STAT3 globally and/or specifically for cancer therapy. In this review, we summarize current literature and discuss the potential importance of STAT3 as a novel target for cancer prevention and of STAT3 inhibitors as effective chemopreventive agents.
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Affiliation(s)
- Ailian Xiong
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Zhengduo Yang
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Yicheng Shen
- College of Natural Sciences, The University of Texas at Austin, Austin, TX 78712, USA.
| | - Jia Zhou
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA.
| | - Qiang Shen
- Department of Clinical Cancer Prevention, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
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The Multifaceted Roles of STAT3 Signaling in the Progression of Prostate Cancer. Cancers (Basel) 2014; 6:829-59. [PMID: 24722453 PMCID: PMC4074806 DOI: 10.3390/cancers6020829] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 03/11/2014] [Accepted: 03/17/2014] [Indexed: 01/09/2023] Open
Abstract
The signal transducer and activator of transcription (STAT)3 governs essential functions of epithelial and hematopoietic cells that are often dysregulated in cancer. While the role for STAT3 in promoting the progression of many solid and hematopoietic malignancies is well established, this review will focus on the importance of STAT3 in prostate cancer progression to the incurable metastatic castration-resistant prostate cancer (mCRPC). Indeed, STAT3 integrates different signaling pathways involved in the reactivation of androgen receptor pathway, stem like cells and the epithelial to mesenchymal transition that drive progression to mCRPC. As equally important, STAT3 regulates interactions between tumor cells and the microenvironment as well as immune cell activation. This makes it a major factor in facilitating prostate cancer escape from detection of the immune response, promoting an immunosuppressive environment that allows growth and metastasis. Based on the multifaceted nature of STAT3 signaling in the progression to mCRPC, the promise of STAT3 as a therapeutic target to prevent prostate cancer progression and the variety of STAT3 inhibitors used in cancer therapies is discussed.
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Smith IJ, Godinez GL, Singh BK, McCaughey KM, Alcantara RR, Gururaja T, Ho MS, Nguyen HN, Friera AM, White KA, McLaughlin JR, Hansen D, Romero JM, Baltgalvis KA, Claypool MD, Li W, Lang W, Yam GC, Gelman MS, Ding R, Yung SL, Creger DP, Chen Y, Singh R, Smuder AJ, Wiggs MP, Kwon OS, Sollanek KJ, Powers SK, Masuda ES, Taylor VC, Payan DG, Kinoshita T, Kinsella TM. Inhibition of Janus kinase signaling during controlled mechanical ventilation prevents ventilation-induced diaphragm dysfunction. FASEB J 2014; 28:2790-803. [PMID: 24671708 PMCID: PMC4062832 DOI: 10.1096/fj.13-244210] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Controlled mechanical ventilation (CMV) is associated with the development of diaphragm atrophy and contractile dysfunction, and respiratory muscle weakness is thought to contribute significantly to delayed weaning of patients. Therefore, therapeutic strategies for preventing these processes may have clinical benefit. The aim of the current study was to investigate the role of the Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) signaling pathway in CMV-mediated diaphragm wasting and weakness in rats. CMV-induced diaphragm atrophy and contractile dysfunction coincided with marked increases in STAT3 phosphorylation on both tyrosine 705 (Tyr705) and serine 727 (Ser727). STAT3 activation was accompanied by its translocation into mitochondria within diaphragm muscle and mitochondrial dysfunction. Inhibition of JAK signaling during CMV prevented phosphorylation of both target sites on STAT3, eliminated the accumulation of phosphorylated STAT3 within the mitochondria, and reversed the pathologic alterations in mitochondrial function, reduced oxidative stress in the diaphragm, and maintained normal diaphragm contractility. In addition, JAK inhibition during CMV blunted the activation of key proteolytic pathways in the diaphragm, as well as diaphragm atrophy. These findings implicate JAK/STAT3 signaling in the development of diaphragm muscle atrophy and dysfunction during CMV and suggest that the delayed extubation times associated with CMV can be prevented by inhibition of Janus kinase signaling.-Smith, I. J., Godinez, G. L., Singh, B. K., McCaughey, K. M., Alcantara, R. R., Gururaja, T., Ho, M. S., Nguyen, H. N., Friera, A. M., White, K. A., McLaughlin, J. R., Hansen, D., Romero, J. M., Baltgalvis, K. A., Claypool, M. D., Li, W., Lang, W., Yam, G. C., Gelman, M. S., Ding, R., Yung, S. L., Creger, D. P., Chen, Y., Singh, R., Smuder, A. J., Wiggs, M. P., Kwon, O.-S., Sollanek, K. J., Powers, S. K., Masuda, E. S., Taylor, V. C., Payan, D. G., Kinoshita, T., Kinsella, T. M. Inhibition of Janus kinase signaling during controlled mechanical ventilation prevents ventilation-induced diaphragm dysfunction.
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Affiliation(s)
- Ira J Smith
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | | | - Baljit K Singh
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | | | | | | | - Melissa S Ho
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Henry N Nguyen
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | | | - Kathy A White
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | | | - Derek Hansen
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Jason M Romero
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | | | - Mark D Claypool
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Wei Li
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Wayne Lang
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - George C Yam
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Marina S Gelman
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Rongxian Ding
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Stephanie L Yung
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Daniel P Creger
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Yan Chen
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Rajinder Singh
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Ashley J Smuder
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Michael P Wiggs
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Oh-Sung Kwon
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Kurt J Sollanek
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Scott K Powers
- Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
| | - Esteban S Masuda
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Vanessa C Taylor
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Donald G Payan
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Taisei Kinoshita
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
| | - Todd M Kinsella
- Rigel Pharmaceuticals, South San Francisco, California, USA; and
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Genetic Interactions of STAT3 and Anticancer Drug Development. Cancers (Basel) 2014; 6:494-525. [PMID: 24662938 PMCID: PMC3980611 DOI: 10.3390/cancers6010494] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 02/18/2014] [Accepted: 02/20/2014] [Indexed: 12/18/2022] Open
Abstract
Signal transducer and activator of transcription 3 (STAT3) plays critical roles in tumorigenesis and malignant evolution and has been intensively studied as a therapeutic target for cancer. A number of STAT3 inhibitors have been evaluated for their antitumor activity in vitro and in vivo in experimental tumor models and several approved therapeutic agents have been reported to function as STAT3 inhibitors. Nevertheless, most STAT3 inhibitors have yet to be translated to clinical evaluation for cancer treatment, presumably because of pharmacokinetic, efficacy, and safety issues. In fact, a major cause of failure of anticancer drug development is lack of efficacy. Genetic interactions among various cancer-related pathways often provide redundant input from parallel and/or cooperative pathways that drives and maintains survival environments for cancer cells, leading to low efficacy of single-target agents. Exploiting genetic interactions of STAT3 with other cancer-related pathways may provide molecular insight into mechanisms of cancer resistance to pathway-targeted therapies and strategies for development of more effective anticancer agents and treatment regimens. This review focuses on functional regulation of STAT3 activity; possible interactions of the STAT3, RAS, epidermal growth factor receptor, and reduction-oxidation pathways; and molecular mechanisms that modulate therapeutic efficacies of STAT3 inhibitors.
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Geletu M, Guy S, Arulanandam R, Feracci H, Raptis L. Engaged for survival: From cadherin ligation to STAT3 activation. JAKSTAT 2013; 2:e27363. [PMID: 24470979 DOI: 10.4161/jkst.27363] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 11/26/2013] [Accepted: 11/27/2013] [Indexed: 12/15/2022] Open
Abstract
In normal tissues or tumors, cells have extensive opportunities for adhesion to their neighbors. This state is mimicked by dense cell cultures. In this review, we integrate some recent findings on a key signal transducer, STAT3 (signal transducer and activator of transcription-3), whose activity is dramatically increased following cadherin-mediated cell to cell adhesion. Cadherin engagement, favored in dense cell cultures, causes a dramatic increase in total Rac/Cdc42 protein levels through inhibition of proteasomal degradation, which is followed by activation of IL-6 and STAT3. The cadherin/Rac/IL-6/STAT3 axis offers a potent survival signal that is a prerequisite for neoplastic transformation, as well as normal tissue function.
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Affiliation(s)
- Mulu Geletu
- Department of Pathology; Queen's University; Kingston, ON Canada
| | - Stephanie Guy
- Department of Pathology; Queen's University; Kingston, ON Canada
| | | | - Hélène Feracci
- Université Bordeaux 1; Centre de Recherche Paul Pascal; CNRS UPR 8641; Pessac, France
| | - Leda Raptis
- Department of Pathology; Queen's University; Kingston, ON Canada ; Department of Biomedical and Molecular Sciences; Queen's University; Kingston, ON Canada
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Yamamoto K, Uda A, Mukai A, Yamashita K, Kume M, Makimoto H, Bito T, Nishigori C, Hirano T, Hirai M. Everolimus-induced human keratinocytes toxicity is mediated by STAT3 inhibition. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2013; 32:83. [PMID: 24423131 PMCID: PMC3874739 DOI: 10.1186/1756-9966-32-83] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 10/21/2013] [Indexed: 11/21/2022]
Abstract
Background Mammalian target of rapamycin (mTOR) inhibitors are associated with dermatological adverse events. The chief aim of this study was to examine the relation between the signal transducer and activator of transcription 3 (STAT3) protein and the dermatological adverse events associated with the mTOR inhibitor everolimus. Methods We evaluated the effects of STAT3 activity and related signal transduction activities on everolimus-induced cell growth inhibition in the human keratinocyte HaCaT cell line via a WST-8 assay, and on signal transduction mechanisms involved in everolimus treatments via a western blot analysis. Apoptosis was evaluated using an imaging cytometric assay. Results The cell growth inhibitory effects of everolimus were enhanced by stattic or STA-21, which are selective inhibitors of STAT3, treatment in HaCaT cells, although such effects were not observed in Caki-1 and HepG2 cells. Phosphorylation at tyrosine 705 of STAT3 was decreased by treatment with everolimus in a dose-dependent manner in HaCaT cells; in contrast, phosphorylation at serine 727 was not decreased by everolimus, but slightly increased. Furthermore, we found that pretreatment of p38 MAPK inhibitor and transfection with constitutively active form of STAT3 in HaCaT cells resisted the cytostatic activity of everolimus. Conclusions These findings suggest that STAT3 activity may be a biomarker of everolimus-induced dermatological toxicity.
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Role of STAT3 in cancer metastasis and translational advances. BIOMED RESEARCH INTERNATIONAL 2013; 2013:421821. [PMID: 24199193 PMCID: PMC3807846 DOI: 10.1155/2013/421821] [Citation(s) in RCA: 283] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 08/25/2013] [Accepted: 08/26/2013] [Indexed: 12/11/2022]
Abstract
Signal transducer and activator of transcription 3 (STAT3) is a latent cytoplasmic transcription factor, originally discovered as a transducer of signal from cell surface receptors to the nucleus. It is activated by tyrosine phosphorylation at position 705 leading to its dimerization, nuclear translocation, DNA binding, and activation of gene transcription. Under normal physiological conditions, STAT3 activation is tightly regulated. However, compelling evidence suggests that STAT3 is constitutively activated in many cancers and plays a pivotal role in tumor growth and metastasis. It regulates cellular proliferation, invasion, migration, and angiogenesis that are critical for cancer metastasis. In this paper, we first describe the mechanism of STAT3 regulation followed by how STAT3 is involved in cancer metastasis, then we summarize the various small molecule inhibitors that inhibit STAT3 signaling.
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Kaposi's sarcoma-associated herpesvirus kaposin B induces unique monophosphorylation of STAT3 at serine 727 and MK2-mediated inactivation of the STAT3 transcriptional repressor TRIM28. J Virol 2013; 87:8779-91. [PMID: 23740979 DOI: 10.1128/jvi.02976-12] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the etiologic agent of primary effusion lymphoma (PEL), multicentric Castleman's disease (MCD), and the inflammation-driven neoplasm Kaposi's sarcoma (KS). A triad of processes, including abnormal proliferation of endothelial cells, aberrant angiogenesis, and chronic inflammation, characterize KS lesions. STAT3 is a key transcription factor governing these processes, and deregulation of STAT3 activity is linked to a wide range of cancers, including PEL and KS. Using primary human endothelial cells (ECs), I demonstrate that KSHV infection modulated STAT3 activation in two ways: (i) KSHV induced uncoupling of canonical tyrosine (Y) and serine (S) phosphorylation events while (ii) concomitantly inducing the phosphorylation and inactivation of TRIM28 (also known as KAP-1 or TIF-1β), a newly identified negative regulator of STAT3 activity. KSHV infection of primary ECs induced chronic STAT3 activation characterized by a shift from the canonical dual P-STAT3 Y705 S727 form to a mono P-STAT3 S727 form. Expression of the latent protein kaposin B promoted the unique phosphorylation of STAT3 at S727, in the absence of Y705, activated the host kinase mitogen-activated protein kinase-activated protein (MAPKAP) kinase 2 (MK2), and stimulated increased expression of STAT3-dependent genes, including CCL5, in ECs. TRIM28-mediated repression of STAT3 is relieved by phosphorylation of S473, and in vitro kinase assays identified TRIM28 S473 as a bona fide target of MK2. Together, these data suggest that kaposin B significantly contributes to the chronic inflammatory environment that is a hallmark of KS by unique activation of the proto-oncogene STAT3, coupled with MK2-mediated inactivation of the STAT3 transcriptional repressor TRIM28.
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Ara T, Nakata R, Sheard MA, Shimada H, Buettner R, Groshen SG, Ji L, Yu H, Jove R, Seeger RC, DeClerck YA. Critical role of STAT3 in IL-6-mediated drug resistance in human neuroblastoma. Cancer Res 2013; 73:3852-64. [PMID: 23633489 DOI: 10.1158/0008-5472.can-12-2353] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Drug resistance is a major cause of treatment failure in cancer. Here, we have evaluated the role of STAT3 in environment-mediated drug resistance (EMDR) in human neuroblastoma. We determined that STAT3 was not constitutively active in most neuroblastoma cell lines but was rapidly activated upon treatment with interleukin (IL)-6 alone and in combination with the soluble IL-6 receptor (sIL-6R). Treatment of neuroblastoma cells with IL-6 protected them from drug-induced apoptosis in a STAT3-dependent manner because the protective effect of IL-6 was abrogated in the presence of a STAT3 inhibitor and upon STAT3 knockdown. STAT3 was necessary for the upregulation of several survival factors such as survivin (BIRC5) and Bcl-xL (BCL2L1) when cells were exposed to IL-6. Importantly, IL-6-mediated STAT3 activation was enhanced by sIL-6R produced by human monocytes, pointing to an important function of monocytes in promoting IL-6-mediated EMDR. Our data also point to the presence of reciprocal activation of STAT3 between tumor cells and bone marrow stromal cells including not only monocytes but also regulatory T cells (Treg) and nonmyeloid stromal cells. Thus, the data identify an IL-6/sIL-6R/STAT3 interactive pathway between neuroblastoma cells and their microenvironment that contributes to drug resistance.
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Affiliation(s)
- Tasnim Ara
- Division of Hematology-Oncology, Department of Pediatrics, Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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Martínez Flores K, Uribe Marín B, Souza Arroyo V, Bucio Ortiz L, López Reyes A, Gómez-Quiroz L, Rojas del Castillo E, Gutiérrez Ruiz M. Hepatocytes display a compensatory survival response against cadmium toxicity by a mechanism mediated by EGFR and Src. Toxicol In Vitro 2013; 27:1031-42. [DOI: 10.1016/j.tiv.2013.01.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 01/03/2013] [Accepted: 01/04/2013] [Indexed: 12/30/2022]
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Park YH, Lee YM, Kim DS, Park J, Suk K, Kim JK, Han HS. Hypothermia enhances induction of protective protein metallothionein under ischemia. J Neuroinflammation 2013; 10:21. [PMID: 23374901 PMCID: PMC3607999 DOI: 10.1186/1742-2094-10-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 01/23/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Hypothermic protection against ischemic stroke has been reported by many studies. Hypothermia is supposed to mitigate the effects of deleterious genes and proteins and promote the activity of protective genes and proteins in the ischemic brain. Metallothionein (MT)-1/2 is thought to be a crucial factor for metal homeostasis, immune function, and apoptosis. This protein was found to exert protective effects in models of brain injury as well. In the present study, we investigated the effect of hypothermia on MT expression and the underlying mechanisms. METHODS Cultured bEnd.3 brain endothelial cells were exposed to oxygen glucose deprivation and reperfusion (OGD+R). Reverse transcription PCR and western blot analyses were performed to measure the expression of MT, transcription factors, and methylation regulating factors. Transcription factor binding assays were also performed. Methylation profiles of the promoter area were obtained with pyrosequencing. RESULTS Hypothermia protected bEnd.3 cells from OGD+R. When the cells were exposed to OGD+R, MT expression was induced. Hypothermia augmented MT levels. While OGD+R-induced MT expression was mainly associated with metal regulatory transcription factor 1 (MTF-1), MT expression promoted by hypothermia was primarily mediated by the signal transducer and activator of transcription 3 (STAT3). Significantly increased STAT3 phosphorylation at Ser727 was observed with hypothermia, and JSI-124, a STAT-3 inhibitor, suppressed MT expression. The DNA demethylating drug 5-aza-2'-deoxycytidine (5-Aza) enhanced MT expression. Some of the CpG sites in the promoter MT=> it should be "the CpG sites in the MT promoter" showed different methylation profiles and some methylation regulating factors had different expressional profiles in the presence of OGD+R and hypothermia. CONCLUSIONS We demonstrated that hypothermia is a potent inducer of MT gene transcription in brain endothelial cells, and enhanced MT expression might contribute to protection against ischemia. MT gene expression is induced by hypothermia mainly through the STAT3 pathway. DNA methylation may contribute to MT gene regulation under ischemic or hypothermic conditions.
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Affiliation(s)
- Youn Hee Park
- Department of Physiology, Kyungpook National University School of Medicine, 101 Dongin 2 Ga, Jung Gu, Daegu 700-422, Korea
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Katz E, Sims AH, Sproul D, Caldwell H, Dixon MJ, Meehan RR, Harrison DJ. Targeting of Rac GTPases blocks the spread of intact human breast cancer. Oncotarget 2013; 3:608-19. [PMID: 22689141 PMCID: PMC3442288 DOI: 10.18632/oncotarget.520] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
High expression of Rac small GTPases in invasive breast ductal carcinoma is associated with poor prognosis, but its therapeutic value in human cancers is not clear. The aim of the current study was to determine the response of human primary breast cancers to Rac-based drug treatments ex vivo. Three-dimensional organotypic cultures were used to assess candidate therapeutic avenues in invasive breast cancers. Uniquely, in these primary cultures, the tumour is not disaggregated, with both epithelial and mesenchymal components maintained within a three-dimensional matrix of type I collagen. EHT 1864, a small molecule inhibitor of Rac GTPases, prevents spread of breast cancers in this setting, and also reduces proliferation at the invading edge. Rac1+ epithelial cells in breast tumours also contain high levels of the phosphorylated form of the transcription factor STAT3. The small molecule Stattic inhibits activation of STAT3 and induces effects similar to those seen with EHT 1864. Pan-Rac inhibition of proliferation precedes down-regulation of STAT3 activity, defining it as the last step in Rac activation during human breast cancer invasion. Our data highlights the potential use of Rac and STAT3 inhibition in treatment of invasive human breast cancer and the benefit of studying novel cancer treatments using three-dimensional primary tumour tissue explant cultures.
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Affiliation(s)
- Elad Katz
- Breakthrough Breast Cancer Research Unit, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom.
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Hepatitis C virus activates Bcl-2 and MMP-2 expression through multiple cellular signaling pathways. J Virol 2012; 86:12531-43. [PMID: 22951829 DOI: 10.1128/jvi.01136-12] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hepatitis C virus (HCV) infection is associated with numerous liver diseases and causes serious global health problems, but the mechanisms underlying the pathogenesis of HCV infections remain largely unknown. In this study, we demonstrate that signal transducer and activator of transcription 3 (STAT3), matrix metalloproteinase-2 (MMP-2), and B-cell lymphoma 2 (Bcl-2) are significantly stimulated in HCV-infected patients. We further show that HCV activates STAT3, MMP-2, Bcl-2, extracellular regulated protein kinase (ERK), and c-Jun N-terminal kinase (JNK) in infected Huh7.5.1 cells. Functional screening of HCV proteins revealed that nonstructural protein 4B (NS4B) is responsible for the activation of MMP-2 and Bcl-2 by stimulating STAT3 through repression of the suppressor of cytokine signaling 3 (SOCS3). Our results also demonstrate that multiple signaling cascades, including several members of the protein kinase C (PKC) family, JNK, ERK, and STAT3, play critical roles in the activation of MMP-2 and Bcl-2 mediated by NS4B. Further studies revealed that the C-terminal domain (CTD) of NS4B is sufficient for the activation of STAT3, JNK, ERK, MMP-2, and Bcl-2. We also show that amino acids 227 to 250 of NS4B are essential for regulation of STAT3, JNK, ERK, MMP-2, and Bcl-2, and among them, three residues (237L, 239S, and 245L) are crucial for this regulation. Thus, we reveal a novel mechanism underlying HCV pathogenesis in which multiple intracellular signaling cascades are cooperatively involved in the activation of two important cellular factors, MMP-2 and Bcl-2, in response to HCV infection.
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Liu J, Chen B, Lu Y, Guan Y, Chen F. JNK-dependent Stat3 phosphorylation contributes to Akt activation in response to arsenic exposure. Toxicol Sci 2012; 129:363-71. [PMID: 22696236 DOI: 10.1093/toxsci/kfs199] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Environmental exposure to arsenic, especially the trivalent inorganic form (As(3+)), has been linked to human cancers in addition to a number of other diseases including skin lesions, cardiovascular disorders, neuropathy, and internal organ injury. In the present study, we describe a novel signaling axis of the c-Jun NH2 kinase (JNK) and signal transducer and activator of transcription 3 (Stat3) and its involvement in As(3+)-induced Akt activation in human bronchial epithelial cells. As(3+) activates JNK and induces phosphorylation of the Stat3 at serine 727 (S727) in a dose- and time-dependent manner, which occurred concomitantly with Akt activation. Disruption of the JNK signaling pathway by treatment with the JNK inhibitor SP600125, siRNA knockdown of JNK, or genetic deficiency of the JNK1 or JNK2 gene abrogated As(3+)-induced S727 phosphorylation of Stat3, Akt activation, and the consequent release of vascular endothelial growth factor (VEGF) and migration of the cells. Similarly, pretreatment of the cells with Stat3 inhibitor or Stat3 siRNA prevented Akt activation and VEGF release from the cells in response to As(3+) treatment. Taken together, these data revealed a new signaling mechanism that might be pivotal in As(3+)-induced malignant transformation of the cells by linking the key stress signaling pathway, JNK, to the activation of Stat3 and the carcinogenic kinase, Akt.
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Affiliation(s)
- Jia Liu
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, Michigan 48201, USA
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Orally bioavailable small-molecule inhibitor of transcription factor Stat3 regresses human breast and lung cancer xenografts. Proc Natl Acad Sci U S A 2012; 109:9623-8. [PMID: 22623533 DOI: 10.1073/pnas.1121606109] [Citation(s) in RCA: 272] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Computer-aided lead optimization derives a unique, orally bioavailable inhibitor of the signal transducer and activator of transcription (Stat)3 Src homology 2 domain. BP-1-102 binds Stat3 with an affinity (K(D)) of 504 nM, blocks Stat3-phospho-tyrosine (pTyr) peptide interactions and Stat3 activation at 4-6.8 μM, and selectively inhibits growth, survival, migration, and invasion of Stat3-dependent tumor cells. BP-1-102-mediated inhibition of aberrantly active Stat3 in tumor cells suppresses the expression of c-Myc, Cyclin D1, Bcl-xL, Survivin, VEGF, and Krüppel-like factor 8, which is identified as a Stat3 target gene that promotes Stat3-mediated breast tumor cell migration and invasion. Treatment of breast cancer cells with BP-1-102 further blocks Stat3-NF-κB cross-talk, the release of granulocyte colony-stimulating factor, soluble intercellular adhesion molecule 1, macrophage migration-inhibitory factor/glycosylation-inhibiting factor, interleukin 1 receptor antagonist, and serine protease inhibitor protein 1, and the phosphorylation of focal adhesion kinase and paxillin, while enhancing E-cadherin expression. Intravenous or oral gavage delivery of BP-1-102 furnishes micromolar or microgram levels in tumor tissues and inhibits growth of human breast and lung tumor xenografts.
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RNA interference-mediated silencing of NANOG reduces cell proliferation and induces G0/G1 cell cycle arrest in breast cancer cells. Cancer Lett 2012; 321:80-8. [PMID: 22381696 DOI: 10.1016/j.canlet.2012.02.021] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 02/03/2012] [Accepted: 02/20/2012] [Indexed: 01/04/2023]
Abstract
Since the processes of normal embryogenesis and neoplasia share many of similar pathways, tumor development has been interpreted as an abnormal form of organogenesis. NANOG is a homeodomain-containing transcription factor that functions to maintain self-renewal and proliferation of embryonic stem cells (ESCs). Aberrant expression of NANOG has been observed in many types of human malignancies. However, its potential implication in tumorigenesis has not been fully clarified. In this study, we have employed small interference RNA (RNAi) technology to silence endogenous NANOG expression in breast cancer cells and successfully selected three independent clones with stably inhibited NANOG expression of MCF-7 cells. Functional analysis revealed that down-regulation of NANOG reduced cell proliferation, colony formation and migration ability of MCF-7 cells. Consistently, proliferation of breast cancer MDA-MB-231 cells was also significantly inhibited after the knockdown of NANOG expression. Interestingly, we found that the expression levels of cyclinD1 and c-myc were markedly down-regulated and the cell cycle were blocked at the G0/G1 phases after the knockdown of NANOG, while the expression of cyclinE and signal transducers and activators of transcription3 (STAT3) remained unaffected. In addition, the expression of NANOG and cyclinD1 can be rescued after the transfection of pcDNA3.1 (-)-NANOG expression vector into the three clones. Finally, our chromatin immunoprecipitation (ChIP) experiment showed that NANOG protein can bind to the promoter region of cyclinD1 and regulate cells cycle. Taken together, our findings may not only establish a molecular basis for the role of NANOG in modulating cell cycle progression of breast cancer cells but also suggest a potential target for the treatment of at least some subtypes of breast cancer.
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Reipschläger S, Kubatzky K, Taromi S, Burger M, Orth J, Aktories K, Schmidt G. Toxin-induced RhoA activity mediates CCL1-triggered signal transducers and activators of transcription protein signaling. J Biol Chem 2012; 287:11183-94. [PMID: 22311973 DOI: 10.1074/jbc.m111.313395] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
RhoA is reportedly involved in signal transducers and activators of transcription (STAT)-dependent transcription. However, the pathway connecting the GTPase and STAT signaling has not been characterized. Here, we made use of bacterial toxins, which directly activate Rho GTPases to analyze this pathway. Cytotoxic necrotizing factors (CNFs) are produced by pathogenic Escherichia coli strains and by Yersinia pseudotuberculosis. They activate small GTPases of the Rho family by deamidation of a glutamine, which is crucial for GTP hydrolysis. We show that RhoA activation leads to phosphorylation and activation of STAT3 and identify signal proteins involved in this pathway. RhoA-dependent STAT3 stimulation requires ROCK and Jun kinase activation as well as AP1-induced protein synthesis. The secretion of one or more factors activates the JAK-STAT pathway in an auto/paracrine manner. We identify CCL1/I-309 as an essential cytokine, which is produced and secreted upon RhoA activation and which is able to activate STAT3-dependent signaling pathways.
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Affiliation(s)
- Simone Reipschläger
- Institute for Experimental and Clinical Pharmacology and Toxicology, Albert-Ludwigs-University of Freiburg, Albert-Str. 25, 79104 Freiburg, Germany
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69
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Zhang Y. A novel bayesian graphical model for genome-wide multi-SNP association mapping. Genet Epidemiol 2011; 36:36-47. [PMID: 22127647 DOI: 10.1002/gepi.20661] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 09/20/2011] [Accepted: 10/05/2011] [Indexed: 11/10/2022]
Abstract
Most disease association mapping algorithms are based on hypothesis testing procedures that test one variant at a time. Those methods lose power when the disease mutations are jointly tagged by multiple variants, or when gene-gene interaction exist. Nearby variants are also correlated, for which procedures ignoring the dependence between variants will inevitably produce redundant results. With a large number of variants genotyped in current genome-wide disease association studies, simultaneous multivariant association mapping algorithms are strongly desired. We present a novel Bayesian method for automatic detection of multivariant joint association in genome-wide case-control studies. Our method has improved power and specificity over existing tools. We fit a joint probabilistic model to the entire data and identify disease variants simultaneously. The method dynamically accounts for the strong linkage disequilibrium (LD) between variants. As a result, only the primary disease variants will be identified, with all secondary associations due to LD effects filtered out. Our method better pinpoints the disease variants with improved resolution. The method is also computationally efficient for genome-wide studies. When applied to a real data set of inflammatory bowel disease (IBD) containing 401,473 variants in 4,720 individuals, our method detected all previously reported IBD loci in the same data, and recovered two missed loci. We further detected two novel interchromosome interactions. The first is between STAT3 and PARD6G, and the second is between DLG5 and an intergenic region at 5p14. We further validated the two interactions in an independent study.
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Affiliation(s)
- Yu Zhang
- Department of Statistics, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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Raptis L, Arulanandam R, Geletu M, Turkson J. The R(h)oads to Stat3: Stat3 activation by the Rho GTPases. Exp Cell Res 2011; 317:1787-95. [PMID: 21619876 DOI: 10.1016/j.yexcr.2011.05.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 05/09/2011] [Accepted: 05/10/2011] [Indexed: 02/09/2023]
Abstract
The signal transducer and activator of transcription-3 (Stat3) is a member of the STAT family of cytoplasmic transcription factors. Overactivation of Stat3 is detected with high frequency in human cancer and is considered a molecular abnormality that supports the tumor phenotype. Despite concerted investigative efforts, the molecular mechanisms leading to the aberrant Stat3 activation and Stat3-mediated transformation and tumorigenesis are still not clearly defined. Recent evidence reveals a crosstalk close relationship between Stat3 signaling and members of the Rho family of small GTPases, including Rac1, Cdc42 and RhoA. Specifically, Rac1, acting in a complex with the MgcRacGAP (male germ cell RacGAP), promotes tyrosine phosphorylation of Stat3 by the IL6-receptor family/Jak kinase complex, as well as its translocation to the nucleus. Studies have further revealed that the mutational activation of Rac1 and Cdc42 results in Stat3 activation, which occurs in part through the upregulation of IL6 family cytokines that in turn stimulates Stat3 through the Jak kinases. Interestingly, evidence also shows that the engagement of cadherins, cell to cell adhesion molecules, specifically induces a striking increase in Rac1 and Cdc42 protein levels and activity, which in turn results in Stat3 activation. In this review we integrate recent findings clarifying the role of the Rho family GTPases in Stat3 activation in the context of malignant progression.
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Affiliation(s)
- Leda Raptis
- Department of Microbiology and Immunology and Pathology, Queen's University, Kingston, Ontario, Canada.
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71
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Song L, Rawal B, Nemeth JA, Haura EB. JAK1 activates STAT3 activity in non-small-cell lung cancer cells and IL-6 neutralizing antibodies can suppress JAK1-STAT3 signaling. Mol Cancer Ther 2011; 10:481-94. [PMID: 21216930 DOI: 10.1158/1535-7163.mct-10-0502] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Members of the signal transducer and activator of transcription (STAT) family of transcription factors are potential targets for the treatment and prevention of cancers including non-small-cell lung cancer. STAT proteins can be phosphorylated and activated by diverse upstream kinases including cytokine receptors and tyrosine kinases. We examined STAT protein activation in lung cancer cell lines including those with activating mutations in the EGFR and examined upstream kinases responsible for STAT3 phosphorylation and activation using small molecules, antibodies, and RNA interference. We found more pronounced STAT3 activation in cells with activating EGFR mutations, yet inhibition of EGFR activity had no effect on STAT3 activation. Inhibition of JAK1 with small molecules or RNA interference resulted in loss of STAT3 tyrosine phosphorylation and inhibition of cell growth. An interleukin-6 neutralizing antibody, siltuximab (CNTO 328) could inhibit STAT3 tyrosine phosphorylation in a cell-dependent manner. Siltuximab could completely inhibit STAT3 tyrosine phosphorylation in H1650 cells, and this resulted in inhibition of lung cancer cell growth in vivo. Combined EGFR inhibition with erlotinib and siltuximab resulted in dual inhibition of both tyrosine and serine STAT3 phosphorylation, more pronounced inhibition of STAT3 transcriptional activity, and translated into combined effects on lung cancer growth in a mouse model. Our results suggest that JAK1 is responsible for STAT3 activation in lung cancer cells and that indirect attacks on JAK1-STAT3 using an IL-6 neutralizing antibody with or without EGFR inhibition can inhibit lung cancer growth in lung cancer subsets.
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Affiliation(s)
- Lanxi Song
- Thoracic Oncology and Experimental Therapeutics Programs H. Lee Moffitt Cancer Center and Research Institute MRC3 East, Room 3056F, 12902 Magnolia Drive Tampa, Florida 33612-9497, USA
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Zhao W, Jaganathan S, Turkson J. A cell-permeable Stat3 SH2 domain mimetic inhibits Stat3 activation and induces antitumor cell effects in vitro. J Biol Chem 2010; 285:35855-65. [PMID: 20807764 DOI: 10.1074/jbc.m110.154088] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Given the role of constitutively active Signal Transducer and Activator of Transcription (Stat) 3 in human tumors, Stat3 inhibitors would be useful as novel therapeutics and as tools for probing Stat3-mediated tumor processes. We herein report that a 28-mer peptide, SPI, derived from the Stat3 SH2 domain, replicates Stat3 biochemical properties. Studies show SPI and Stat3 (or Stat3 SH2 domain) bind with similar affinities to known Stat3-binding phosphotyrosine (pY) peptide motifs, including those of the epidermal growth factor receptor (EGFR) and the high-affinity, IL-6R/gp130-derived pY-peptide, GpYLPQTV-NH(2). Consequently, SPI functions as a potent and selective inhibitor of Stat3 SH2 domain:pTyr interactions and disrupts the binding of Stat3 to the IL-6R/gp130 peptide, GpYLPQTV-NH(2). Fluorescence imaging and immunofluorescence staining/laser-scanning confocal microscopy show SPI is cell membrane-permeable, associates with the cytoplasmic tail of EGFR in NIH3T3/hEGFR, and is present in the cytoplasm, but strongly localized at the plasma membrane and in the nucleus in malignant cells harboring persistently active Stat3. Moreover, SPI specifically blocks constitutive Stat3 phosphorylation, DNA binding activity, and transcriptional function in malignant cells, with little or no effect on the induction of Stat1, Stat5, and Erk1/2(MAPK) pathways, or on general pTyr profile at the concentrations that inhibit Stat3 activity. Significantly, treatment with SPI of human breast, pancreatic, prostate, and non-small cell lung cancer cells harboring constitutively active Stat3 induced extensive morphology changes, associated with viability loss and apoptosis. Our study identifies SPI as a novel molecular probe for interrogating Stat3 signaling and that functions as a selective inhibitor of Stat3 activation with antitumor cell effects.
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Affiliation(s)
- Wei Zhao
- Burnett School of Biomedical Sciences, University of Central Florida College of Medicine, Orlando, Florida 32827, USA
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73
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Yeh HH, Giri R, Chang TY, Chou CY, Su WC, Liu HS. Ha-ras oncogene-induced Stat3 phosphorylation enhances oncogenicity of the cell. DNA Cell Biol 2010; 28:131-9. [PMID: 19182994 DOI: 10.1089/dna.2008.0762] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The ras oncogene needs a second factor to induce transformation and tumorigenicity of the cell. In this study, we show that mouse fibroblast 7-4-Stat3C cells overexpressing both Ha-ras(val12) oncogene and active-form Stat3 (Stat3C) showed higher colony formation in soft agar and xenograft tumor growth in BALB/c mice. Further studies show that both serine-727 and tyrosine-705 of Stat3 were phosphorylated while Ha-ras was overexpressed. Interleukin-6 (IL-6)-induced phosphorylation of tyrosine-705 and serine-727, as well as DNA-binding and transcriptional activity of Stat3 were further enhanced by Ha-ras overexpression. In addition, overexpression of Stat3C in 7-4-Stat3C cells prevented the cells from morphological change and apoptosis triggered by the Ha-ras oncogene under serum-depleted conditions. We demonstrate that Ha-ras and Stat3 acting together synergistically induce Stat3 phosphorylation at serine-727 phosphorylation and cyclin D1 expression and further enhance transformation and tumorigenicity of the cell. Ha-ras-induced Stat3 phosphorylation at serine-727 plays a pivotal role in transcriptional activation of cyclin D1 and suppression of cell apoptosis. The effect of Ha-ras on Stat3 phosphorylation at serine-727 was also detected in human bladder (T24) and lung (H460) cancer cells. Stat3 phosphorylation at serine-727 is important in Ras-related tumorigenesis.
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Affiliation(s)
- Hsuan-Heng Yeh
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China
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74
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Wallerstedt E, Smith U, Andersson CX. Protein kinase C-delta is involved in the inflammatory effect of IL-6 in mouse adipose cells. Diabetologia 2010; 53:946-54. [PMID: 20151299 DOI: 10.1007/s00125-010-1668-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Accepted: 12/17/2009] [Indexed: 01/01/2023]
Abstract
AIMS/HYPOTHESIS The aim of the study was to address the role of protein kinase C-delta (PKCdelta) on phosphorylation of signal transducer and activator of transcription 3 (STAT3) and activation of inflammatory genes in response to IL-6 in adipose cells. METHODS Differentiated mouse 3T3-L1 adipocytes preincubated with the PKCdelta inhibitor rottlerin and mouse embryonic fibroblasts (MEFs) lacking PKCdelta were incubated with IL-6 and/or insulin. RNA was extracted and the gene expression was analysed by real-time PCR, while the proteins from total, nuclear and cytoplasmic lysates were analysed by immunoblotting. RESULTS Inhibition of PKCdelta by rottlerin significantly reduced both Ser-727 and Tyr-705 phosphorylation of STAT3. Consequently, nuclear translocation of STAT3 and the IL-6-induced gene transcription and protein release of the inflammatory molecule serum amyloid A 3 (SAA3) were reduced. Similarly, the IL-6-regulated gene transcription of Il-6 (also known as Il6) to Hp and the feedback inhibitor of IL-6, Socs3, were also attenuated by rottlerin. Furthermore, PKCdelta was found to translocate to the nucleus following IL-6 treatment and this was also reduced by rottlerin. In agreement with the effect of rottlerin, Pkcdelta (also known as Prkcd) ( -/- ) MEFs also displayed a markedly reduced ability of IL-6 to activate the transcription of Saa3, Hp, Socs3 and Il6 genes compared with wild-type MEFs. These results correlated with a reduced nuclear translocation and phosphorylation of STAT3. CONCLUSIONS/INTERPRETATION These results show that PKCdelta plays a key role in the inflammatory effect of IL-6 in adipose cells and may be a suitable target for novel anti-inflammatory agents.
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Affiliation(s)
- E Wallerstedt
- The Lundberg Laboratory for Diabetes Research, Center of Excellence for Cardiovascular and Metabolic Research, Department of Molecular and Clinical Medicine/Diabetes, The Sahlgrenska Academy at University of Gothenburg, Blå Stråket 5, SE-413 45, Gothenburg, Sweden
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75
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Abstract
Src is a non-receptor cytoplasmic tyrosine kinase which becomes activated following the stimulation of plasma membrane receptors including receptor tyrosine kinases and integrins, and is an indispensable player of multiple physiological homeostatic pathways. Once activated, Src is the starting point for several biochemical cascades that thereby propagate signals generated extracellularly along intracellular interconnected transduction pathways. Src transmits signals promoting cell survival and mitogenesis and, in addition, exerts a profound effect on the reorganization of the cytoskeleton and the adhesion systems that underpin cell migration and invasion. Because increased activity of Src is a frequent occurrence in many types of human cancer, and because there is evidence of a prominent role of Src in invasion and in other tumor progression-related events such as epithelial-mesenchymal transition (EMT) and development of metastasis, inhibitors targeting Src are being viewed as promising drugs for cancer therapy.
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Affiliation(s)
- Marcello Guarino
- Department of Pathology, Hospital of Vimercate, Vimercate, MB, Italy.
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76
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Zhang X, Yue P, Fletcher S, Zhao W, Gunning PT, Turkson J. A novel small-molecule disrupts Stat3 SH2 domain-phosphotyrosine interactions and Stat3-dependent tumor processes. Biochem Pharmacol 2010; 79:1398-409. [PMID: 20067773 DOI: 10.1016/j.bcp.2010.01.001] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2009] [Revised: 12/10/2009] [Accepted: 01/04/2010] [Indexed: 10/20/2022]
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.
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Affiliation(s)
- Xiaolei Zhang
- University of Central Florida College of Medicine, Orlando, 32827, USA
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78
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Yubero S, Ramudo L, Manso MA, De Dios I. Mechanisms of dexamethasone-mediated chemokine down-regulation in mild and severe acute pancreatitis. Biochim Biophys Acta Mol Basis Dis 2009; 1792:1205-11. [PMID: 19818401 DOI: 10.1016/j.bbadis.2009.10.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2009] [Revised: 09/28/2009] [Accepted: 10/01/2009] [Indexed: 01/27/2023]
Abstract
This study aimed to investigate the role of therapeutic dexamethasone (Dex) treatment on the mechanisms underlying chemokine expression during mild and severe acute pancreatitis (AP) experimentally induced in rats. Regardless of the AP severity, Dex (1 mg/kg), administered 1 h after AP, reduced the acinar cell activation of extracellular signal-regulated kinase (ERK) and c-Jun-NH(2)-terminal kinase (JNK) but failed to reduce p38-mitogen-activated protein kinase (MAPK) in severe AP. In both AP models, Dex inhibited the activation of nuclear factor-kappaB (NF-kappaB) and signal transducers and activators of transcription (STAT) factors. All of this resulted in pancreatic down-regulation of the chemokines monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant (CINC). Lower plasma chemokine levels as well as decreased amylasemia, hematocrit and plasma interleukin-1beta (Il-1beta) levels were found either in mild or severe AP treated with Dex. Pancreatic neutrophil infiltration was attenuated by Dex in mild but not in severe AP. In conclusion, by targeting MAPKs, NF-kappaB and STAT3 pathways, Dex treatment down-regulated the chemokine expression in different cell sources during mild and severe AP, resulting in decreased severity of the disease.
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Affiliation(s)
- S Yubero
- Department of Physiology and Pharmacology, University of Salamanca, 37007 Salamanca, Spain
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79
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Broom OJ, Widjaya B, Troelsen J, Olsen J, Nielsen OH. Mitogen activated protein kinases: a role in inflammatory bowel disease? Clin Exp Immunol 2009; 158:272-80. [PMID: 19793335 DOI: 10.1111/j.1365-2249.2009.04033.x] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Since their discovery more than 15 years ago, the mitogen activated protein kinases (MAPK) have been implicated in an ever-increasingly diverse array of pathways, including inflammatory signalling cascades. Inflammatory bowel diseases (IBD), such as ulcerative colitis and Crohn's disease, are characterized by the perpetual production of inflammatory mediators. Research into the transduction pathway behind this over-production has highlighted the potential mediating role for the MAPKs and their related signalling components. This review highlights some of the research into the role for the MAPKs and their related signalling proteins in influencing the progression of IBD.
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Affiliation(s)
- O J Broom
- Department of Gastroenterology, Medical Section, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
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80
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Doki N, Kawashima T, Nomura Y, Tsuchiya A, Oneyama C, Akagi T, Nojima Y, Kitamura T. Constitutive phosphorylation of a Rac GAP MgcRacGAP is implicated in v-Src-induced transformation of NIH3T3 cells. Cancer Sci 2009; 100:1675-9. [PMID: 19555392 PMCID: PMC11158231 DOI: 10.1111/j.1349-7006.2009.01235.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 05/16/2009] [Accepted: 05/20/2009] [Indexed: 11/28/2022] Open
Abstract
MgcRacGAP plays critical roles in cell division through regulating Rho family small GTPases. As we previously reported, phosphorylation of MgcRacGAP on serine 387 (S387) is induced by Aurora B kinase at the midbody during cytokinesis, which is a critical step of cytokinesis. Phosphorylation of S387-MgcRacGAP converts it from RacGAP to RhoGAP, leading to completion of cytokinesis. Here we show that MgcRacGAP is prominently phosphorylated on S387 even in the interphase of v-Src-transformed NIH3T3 cells in the cytoplasm, but not in the interphase of parental NIH3T3 or H-RasV12-transformed NIH3T3 cells. Interestingly, levels of phosphorylation on S387 (pS387) correlated with soft agar colony-forming abilities of v-Src-transformed NIH3T3 cells. Expression of a phosphorylation-mimic mutant MgcRacGAP-S387D enhanced colony formation of v-Src-transformed NIH3T3 cells. Surprisingly, a Rac1 inhibitor but not kinase inhibitors including Aurora B kinase inhibitor specifically inhibited phosphorylation of S387-MgcRacGAP in v-Src-transformed NIH3T3 cells, suggesting the v-Src-induced pathological positive feedback mechanisms towards Rac1 activation using pS387-MgcRacGAP. These results indicated the difference in the mechanisms between v-Src- and H-RasV12-induced transformation, and should shed some light on pathological roles of disordered phosphorylation of MgcRacGAP at S387 in v-Src-induced cell transformation.
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Affiliation(s)
- Noriko Doki
- Division of Cellular Therapy, The Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo, Japan
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81
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Kroeger KM, Sullivan BM, Locksley RM. IL-18 and IL-33 elicit Th2 cytokines from basophils via a MyD88- and p38alpha-dependent pathway. J Leukoc Biol 2009; 86:769-78. [PMID: 19451398 DOI: 10.1189/jlb.0708452] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
IL-4 and IL-13 are instrumental in the development and progression of allergy and atopic disease. Basophils represent a key source of these cytokines and produce IL-4 and IL-13 when stimulated with IL-18, a member of the IL-1 family of cytokines. Comparative analyses of the effects of caspase-1-dependent IL-1 family cytokines on basophil IL-4 and IL-13 production have not been performed, and the signaling pathway proteins required for FcepsilonRI-independent Th2 cytokine production from basophils remain incompletely defined. Using mouse bone marrow-derived cultured basophils, we found that IL-4 and IL-13 are produced in response to IL-18 or IL-33 stimulation. IL-18- or IL-33-mediated Th2 cytokine production is dependent on MyD88 and p38alpha signaling proteins. In addition, basophil survival increased in the presence of IL-18 or IL-33 as a result of increased Akt activation. Studies in vivo confirmed the potency of IL-18 and IL-33 in activating cytokine release from mouse basophils.
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Affiliation(s)
- Kelly M Kroeger
- Howard Hughes Medical Institute, Departments of Medicine and Microbiology/Immunology, University of California San Francisco, San Francisco, California, USA
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82
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Choi HJ, Lee JH, Park SY, Cho JH, Han JS. STAT3 is involved in phosphatidic acid-induced Bcl-2 expression in HeLa cells. Exp Mol Med 2009; 41:94-101. [PMID: 19287190 DOI: 10.3858/emm.2009.41.2.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Phosphatidic acid (PA), the product of a PLD-mediated reaction, is a lipid second messenger that participates in various intracellular signaling events and is known to regulate a growing list of signaling proteins. We found that Bcl-2 was upregulated by PA treatment in HeLa cells. However, how PA upregulates Bcl-2 expression has not yet been studied. In this study, we tried to discover the mechanisms of Bcl-2 up-regulation by PA treatment in HeLa cells. Treatment with PA resulted in significantly increased expression of Bcl-2 in HeLa cells. Moreover, PA-induced Bcl-2 expression was blocked by mepacrine, an inhibitor of PLA2, but not by propranolol, an inhibitor of PA phospholyhydrolase (PAP). Treatment of 1,2-dipalmitoryl-sn-glycero-3- phosphate (DPPA) also increased Bcl-2 expression. These results indicate that Bcl-2 expression is mediated by lysophosphatidic acid (LPA), not by arachidonic acid (AA). Thereafter, we used MEK1/2 inhibitor, PD98059 to investigate the relationship between ERK1/2 MAPK and PA-induced Bcl-2 expression. PA-induced Bcl-2 expression was decreased when ERK1/2 was inhibited by PD98059. The transcription factor such as STAT3 which is controlled by ERK1/2 MAPK was increased along with Bcl-2 expression when the cells were treated with PA. Furthermore, STAT3 siRNA treatments inhibited PA-induced Bcl-2 expression, suggesting that STAT3 (Ser727) is involved in PA-induced Bcl-2 expression. Taken together, these findings indicate that PA acts as an important mediator for increasing Bcl-2 expression through STAT3 (Ser727) activation via the ERK1/2 MAPK pathway.
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Affiliation(s)
- Hye-Jin Choi
- Department of Biochemistry and Molecular Biology, College of Medicine, Hanyang University, Seoul 133-791, Korea
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83
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Garcia de Aquino S, Manzolli Leite FR, Stach-Machado DR, Francisco da Silva JA, Spolidorio LC, Rossa C. Signaling pathways associated with the expression of inflammatory mediators activated during the course of two models of experimental periodontitis. Life Sci 2009; 84:745-54. [PMID: 19285515 DOI: 10.1016/j.lfs.2009.03.001] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2008] [Revised: 02/19/2009] [Accepted: 03/01/2009] [Indexed: 10/21/2022]
Abstract
AIMS Evaluate the signaling pathways associated with inflammatory mediators activated in two models of experimental periodontitis. MAIN METHODS Two models were used: lipopolysaccharide (LPS) injections and ligature placement. Wistar rats were used and 30 microg LPS from Escherichia coli was injected twice a week into the palatal aspect of the upper molars. Ligatures were placed around lower first molars. A control group received injections of PBS on the palatal gingivae whereas no ligatures were placed on the lower molars. Samples were collected 5, 15 and 30 days and processed for analysis by Western blotting and stereometry. KEY FINDINGS The ligature model was associated with rapid and transient activation of extracellular-regulated kinases (ERK) and p38 mitogen-activated protein kinase (MAPK) as well as of nuclear factor kappa B (NF-kappaB). Activation of these signaling pathways on the LPS model was delayed but sustained throughout the 30-day experimental period. Inflammatory changes induced by both models were similar; however there was a significant reduction on inflammation degree on the ligature model, which paralleled the decrease observed on the activation of the signaling pathways. Activation of signal transducer and activator of transcription (STAT)-3 by phosphorylation of Tyrosine residues and of STAT-5 was observed only on the ligature model. SIGNIFICANCE Regulation of gene expression results from the activation of signaling pathways initiated by receptor-ligand binding of external antigens and also of cytokines produced by the host immune system. Understanding the signaling pathways relevant for a given condition may provide information useful for novel therapeutic approaches.
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Affiliation(s)
- Sabrina Garcia de Aquino
- Department of Diagnosis and Surgery, School of Dentistry at Araraquara, State University of Sao Paulo, Rua Humaita, 1680-Centro, Araraquara, SP 14801-903, Brazil
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84
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Ramnath RD, Sun J, Bhatia M. Involvement of SRC family kinases in substance P-induced chemokine production in mouse pancreatic acinar cells and its significance in acute pancreatitis. J Pharmacol Exp Ther 2009; 329:418-28. [PMID: 19211920 DOI: 10.1124/jpet.108.148684] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Substance P is known to play a key role in the pathogenesis of acute pancreatitis. Src family kinases (SFKs) are known to be involved in cytokine signaling. However, the involvement of SFKs in substance P-induced chemokine production and its role in acute pancreatitis have not been investigated yet. To that end, we have used primary preparations of mouse pancreatic acinar cells as our model to show that substance P/neurokinin 1 receptor (NK1R) induced activation of SFKs. SFKs mediated the activation of mitogen-activated protein kinases [extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase (JNK)], transcription factors [signal transducer and activator of transcription (STAT) 3, nuclear factor (NF) kappaB, activator protein-1 (AP-1)], and production of chemokines in pancreatic acinar cells. We further tested the significance of the SFK signaling pathway in acute pancreatitis. Our results show, for the first time, that treatment of mice with the potent and selective SFK inhibitor PP2 [4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo [3,4-D] pyrimidine], but not its negative inhibitor PP3 (4-amino-7-phenylpyrazol [3,4-D] pyrimidine), reduced the severity of pancreatitis. This was proven by significant attenuation of hyperamylasemia, pancreatic myeloperoxidase activity, chemokines, and water content. Histological evidence of diminished pancreatic injury also confirmed the protective effect of the inhibition of SFKs. Moreover, treatment with the substance P receptor antagonist CP96345 [(2S,3S)-cis-2-(diphenylmethyl)-N-((2-methoxyphenyl)-methyl)-1-azabicyclo(2.2.2.)-octan-3-amine] attenuated acute pancreatitis-induced activation of SFKs, ERK, JNK, STAT3, NFkappaB, and AP-1. The proposed signaling pathway through which substance P mediates acute pancreatitis is through substance P/NK1R-SFKs-(ERK, JNK)-(STAT3, NFkappaB, AP-1) chemokines. In light of our study, we propose that drugs targeting the substance P-mediated signaling pathways could prove beneficial in improving treatment efficacy in acute pancreatitis.
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85
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Kim MJ, Byun JY, Yun CH, Park IC, Lee KH, Lee SJ. c-Src-p38 mitogen-activated protein kinase signaling is required for Akt activation in response to ionizing radiation. Mol Cancer Res 2009; 6:1872-80. [PMID: 19074832 DOI: 10.1158/1541-7786.mcr-08-0084] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Akt and mitogen-activated protein kinase (MAPK) pathways have been implicated in tumor cell survival and contribute to radiation resistance. However, the molecular basis for link between MAPK and Akt in cell survival response to radiation is unclear. Here, we show that c-Src-Rac1-p38 MAPK pathway signals Akt activation and cell survival in response to radiation. Ionizing radiation triggered Thr(308) and Ser(473) phosphorylation of Akt. Exposure of cells to radiation also induced p38 MAPK and c-Jun NH(2)-terminal kinase activations. Inhibition of c-Jun NH(2)-terminal kinase suppressed radiation-induced cell death, whereas inhibition of p38 MAPK effectively increased sensitivity to radiation. Interestingly, inhibition of p38 MAPK completely attenuated radiation-induced Ser(473) phosphorylation of Akt but did not affect Thr(308) phosphorylation. Conversely, overexpression of p38 MAPK enhanced Ser(473) phosphorylation of Akt in response to radiation. In addition, inhibition of p38 MAPK failed to alter phosphoinositide 3-kinase and phosphoinositide-dependent protein kinase activities. Ectopic expression of RacN17, dominant-negative form of Rac1, inhibited p38 MAPK activation and Ser(473) phosphorylation of Akt. Following exposure to radiation, c-Src was selectively activated among Src family tyrosine kinases. Inhibition of c-Src attenuated Rac1 and p38 MAPK activations and Ser(473) phosphorylation of Akt. Our results support the notion that the c-Src-Rac1-p38 MAPK pathway is required for activation of Akt in response to radiation and plays a cytoprotective role against radiation in human cancer cells.
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Affiliation(s)
- Min-Jung Kim
- Laboratory of Molecular Biochemistry, Department of Chemistry, Hanyang University, 17 Haengdang-Dong, Seongdong-Gu, Seoul, Korea
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86
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Yu MY, Ho MK, Liu AM, Wong YH. Mutations on the Switch III region and the alpha3 helix of Galpha16 differentially affect receptor coupling and regulation of downstream effectors. J Mol Signal 2008; 3:17. [PMID: 19025606 PMCID: PMC2613389 DOI: 10.1186/1750-2187-3-17] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Accepted: 11/22/2008] [Indexed: 12/18/2022] Open
Abstract
Background Gα16 can activate phospholipase Cβ (PLCβ) directly like Gαq. It also couples to tetratricopeptide repeat 1 (TPR1) which is linked to Ras activation. It is unknown whether PLCβ and TPR1 interact with the same regions on Gα16. Previous studies on Gαq have defined two minimal clusters of amino acids that are essential for the coupling to PLCβ. Cognate residues in Gα16 might also be essential for interacting with PLCβ, and possibly contribute to TPR1 interaction and other signaling events. Results Alanine mutations were introduced to the two amino acid clusters (246–248 and 259–260) in the switch III region and α3 helix of Gα16. Regulations of PLCβ and STAT3 were partially weakened by each cluster mutant. A mutant harboring mutations at both clusters generally produced stronger suppressions. Activation of Jun N-terminal kinase (JNK) by Gα16 was completely abolished by mutating either clusters. Contrastingly, phosphorylations of extracellular signal-regulated kinase (ERK) and nuclear factor κB (NF-κB) were not significantly affected by these mutations. The interactions between the mutants and PLCβ2 and TPR1 were also reduced in co-immunoprecipitation assays. Coupling between G16 and different categories of receptors was impaired by the mutations, with the effect of switch III mutations being more pronounced than those in the α3 helix. Mutations of both clusters almost completely abolished the receptor coupling and prevent receptor-induced Gβγ release. Conclusion The integrity of the switch III region and α3 helix of Gα16 is critical for the activation of PLCβ, STAT3, and JNK but not ERK or NF-κB. Binding of Gα16 to PLCβ2 or TPR1 was reduced by the mutations of either cluster. The same region could also differentially affect the effectiveness of receptor coupling to G16. The studied region was shown to bear multiple functionally important roles of G16.
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Affiliation(s)
- May Ym Yu
- Department of Biochemistry, Molecular Neuroscience Center and Biotechnology Research Institute, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, PR China.
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87
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Zhang H, Feng W, Liao W, Ma X, Han Q, Zhang Y. The gp130/STAT3 signaling pathway mediates beta-adrenergic receptor-induced atrial natriuretic factor expression in cardiomyocytes. FEBS J 2008; 275:3590-7. [PMID: 18537819 DOI: 10.1111/j.1742-4658.2008.06504.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
beta-Adrenergic receptor (beta-AR)-induced cardiac remodeling is closely linked with the re-expression of the atrial natriuretic factor (ANF) gene. However, the exact molecular mechanism of this response remains elusive. Here, we demonstrate that the beta-AR agonist isoproterenol potently evokes the tyrosine phosphorylation of STAT3 and increases its transcriptional activity in an extracellularly regulated kinase 1/2 and glycoprotein (gp)130 signaling-dependent manner in rat cardiomyocytes. Interestingly, both specific silencing of signal transducers and activators of transcription 3 (STAT3) expression by lentivirus-mediated RNA interference and antagonism of gp130 signaling lead to significant inhibition of isoproterenol-stimulated ANF expression. Together, these results indicate that gp130/STAT3 signaling has an essential role in ANF expression by beta-AR stimulation.
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Affiliation(s)
- Hui Zhang
- Institute of Vascular Medicine, Peking University Third Hospital and Key Laboratory of Molecular Cardiovascular Sciences, Ministry of Education, Beijing, China
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88
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Abstract
Maintaining T cell homeostasis is critical for normal immune response. Three sequential signals activate T cells, with signal 3 delivered by multiple cytokines that regulate cell proliferation, differentiation, and survival/death. Cytokines binding to their receptors engages two key molecular families, namely, Janus tyrosine kinases (Jaks) and signal transducers and activators of transcription (Stats). Among Stats, Stat3 is involved in the generation of T helper 17 (Th17) cells, regulation of dendritic cells, and acute inflammatory response. These aspects of Stat3 function are important for transplantation. We discuss Stat3's role in innate and adaptive immunity as well as its potential for therapeutic intervention.
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89
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Miyazaki T, Bub JD, Iwamoto Y. c-Jun NH(2)-terminal kinase mediates leptin-stimulated androgen-independent prostate cancer cell proliferation via signal transducer and activator of transcription 3 and Akt. Biochim Biophys Acta Mol Basis Dis 2008; 1782:593-604. [PMID: 18718531 DOI: 10.1016/j.bbadis.2008.07.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 07/06/2008] [Accepted: 07/24/2008] [Indexed: 02/04/2023]
Abstract
Obesity is associated with advanced prostate cancer. Here we demonstrate that in mouse prostate cancer TRAMP-C1 cells epididymal fat extracts from high-fat diet-fed obese mice stimulate androgen-independent cell growth more significantly than those from low-fat diet-fed lean mice or genetically obese leptin-deficient ob/ob mice in correlation with leptin concentrations. This result suggests that obesity promotes androgen-independent prostate cancer cell growth via adipose leptin. We have reported that added leptin stimulates androgen-independent prostate cancer cell proliferation through c-Jun NH(2)-terminal kinase (JNK). As with JNK, signal transducer and activator of transcription 3 (STAT3) and Akt are implicated in androgen-independent prostate cancer. In this study, we identify novel interaction of these three molecules in leptin-stimulated androgen-independent cell proliferation. Leptin activates JNK, STAT3 and Akt in a biphasic manner with a similar time-course. Pharmacological JNK inhibition suppresses leptin-stimulated DNA binding activity, as well as Ser-727 phosphorylation, of STAT3. Since JNK upregulates STAT3 activity via Ser-727 phosphorylation, JNK mediates leptin-stimulated STAT3 activation through Ser-727 phosphorylation. Moreover, JNK inhibition impairs leptin-stimulated Ser-473 phosphorylation of Akt that is required for its activation. Thus, JNK is involved in leptin-stimulated Akt activation. These findings together indicate that JNK mediates leptin-stimulated androgen-independent prostate cancer cell proliferation via STAT3 and Akt.
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Affiliation(s)
- Toshiaki Miyazaki
- Department of Surgical Research, Beckman Research Institute of the City of Hope, Duarte, CA 91010-3000, USA
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90
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Mountzios G, Fouret P, Soria JC. Mechanisms of Disease: signal transduction in lung carcinogenesis -- a comparison of smokers and never-smokers. ACTA ACUST UNITED AC 2008; 5:610-8. [PMID: 18628738 DOI: 10.1038/ncponc1181] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Accepted: 01/31/2008] [Indexed: 01/19/2023]
Abstract
Although smoking has been established as the most important cause of lung cancer, approximately 10% of patients with this malignancy have no history of smoking. The pathogenesis of tobacco-related lung carcinogenesis is becoming well characterized, but the molecular mechanisms of neoplastic transformation in never-smokers have not yet been adequately elucidated. Nevertheless, numerous recent studies have revealed a distinct biological process of malignant transformation with unique epidemiological and clinicopathological characteristics in never-smokers. The molecular pathways involved in the differential pattern of lung oncogenesis according to smoking status, however, remain fairly obscure. Researchers have studied several molecular pathways implicated in lung carcinogenesis in smokers and never-smokers, examining these processes at the genomic, epigenetic and proteomic level. The differential protein expression according to smoking status in critical signal transduction pathways has attracted scientific interest because of the possibilities of therapeutic intervention. In this Review we describe the best-characterized signaling pathways implicated in the transduction of proliferative signals and discuss the activity of these pathways in smokers and never-smokers.
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Affiliation(s)
- Giannis Mountzios
- Department of Clinical Therapeutics, University of Athens Medical School, University Hospital Alexandra, Athens, Greece.
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91
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Han C, Bowen WC, Michalopoulos GK, Wu T. Alpha-1 adrenergic receptor transactivates signal transducer and activator of transcription-3 (Stat3) through activation of Src and epidermal growth factor receptor (EGFR) in hepatocytes. J Cell Physiol 2008; 216:486-97. [PMID: 18314882 DOI: 10.1002/jcp.21420] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hepatocytes express adrenergic receptors (ARs) that modulate several functions, including liver regeneration, hepatocyte proliferation, glycogenolysis, gluconeogenesis, synthesis of urea and fatty acid metabolism. Adrenergic hepatic function in adults is mainly under the control of alpha(1)-ARs; however, the mechanism through which they influence diverse processes remains incompletely understood. This study describes a novel alpha(1)-AR-mediated transactivation of signal transducer and activator of transcription-3 (Stat3) in primary and transformed hepatocytes. Treatment of primary rat hepatocytes with the alpha(1)-AR agonist, phenylephrine (PE), induced a rapid phosphorylation of Stat3. PE also increased Stat3 phosphorylation, DNA binding and transcription activity in transformed human hepatocellular carcinoma cells (Hep3B). The PE-induced Stat3 phosphorylation, DNA binding and reporter activity were completely blocked by the selective alpha(1)-AR antagonist, prazosin. In addition, transfection of Hep3B cells with human alpha(1B)-AR expression vector also enhanced Stat3 phosphorylation and reporter activity. Moreover, overexpression of RGS2, a protein inhibitor of G(q/11) signaling, blocked PE-induced Stat3 phosphorylation and reporter activity. The observations that PE induced the formation of c-Src-Stat3 binding complex and phosphorylation of epidermal growth factor receptor (EGFR) and that inhibiting Src and EGFR prevented PE-induced Stat3 activation indicate the involvement of Src and EGFR. Taken together, these observations demonstrate a novel alpha(1)-AR-mediated Stat3 activation that involves G(q/11), Src, and EGFR in hepatic cells.
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Affiliation(s)
- Chang Han
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA
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92
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Pincheira R, Castro AF, Ozes ON, Idumalla PS, Donner DB. Type 1 TNF Receptor Forms a Complex with and Uses Jak2 and c-Src to Selectively Engage Signaling Pathways That Regulate Transcription Factor Activity. THE JOURNAL OF IMMUNOLOGY 2008; 181:1288-98. [DOI: 10.4049/jimmunol.181.2.1288] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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93
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v-Src oncogene product increases sphingosine kinase 1 expression through mRNA stabilization: alteration of AU-rich element-binding proteins. Oncogene 2008; 27:6023-33. [PMID: 18574469 DOI: 10.1038/onc.2008.198] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Sphingosine kinase 1 (SPHK1) is overexpressed in solid tumors and leukemia. However, the mechanism of SPHK1 overexpression by oncogenes has not been defined. We found that v-Src-transformed NIH3T3 cells showed a high SPHK1 mRNA, SPHK1 protein and SPHK enzyme activity. siRNA of SPHK1 inhibited the growth of v-Src-NIH3T3, suggesting the involvement of SPHK1 in v-Src-induced oncogenesis. v-Src-NIH3T3 showed activations of protein kinase C-alpha, signal transducers and activators of transcription 3 and c-Jun NH(2)-terminal kinase. Their inhibition suppressed SPHK1 expression in v-Src-NIH3T3, whereas their overexpression increased SPHK1 mRNA in NIH3T3. Unexpectedly, the nuclear run-on assay and the promoter analysis using 5'-promoter region of mouse SPHK1 did not show any significant difference between mock- and v-Src-NIH3T3. Furthermore, the half-life of SPHK1 mRNA in mock-NIH3T3 was nearly 15 min, whereas that of v-Src-NIH3T3 was much longer. Examination of two AU-rich region-binding proteins, AUF1 and HuR, that regulate mRNA decay reciprocally, showed decreased total AUF1 protein associated with increased tyrosine-phosphorylated form and increased serine-phosphorylated HuR protein in v-Src-NIH3T3. Modulation of AUF1 and HuR by their overexpression or siRNA revealed that SPHK1 mRNA in v-Src- and mock-NIH3T3 was regulated reciprocally by these factors. Our results showed, for the first time, a novel mechanism of v-Src-induced SPHK1 overexpression.
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94
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Bourguignon LYW, Peyrollier K, Xia W, Gilad E. Hyaluronan-CD44 interaction activates stem cell marker Nanog, Stat-3-mediated MDR1 gene expression, and ankyrin-regulated multidrug efflux in breast and ovarian tumor cells. J Biol Chem 2008; 283:17635-51. [PMID: 18441325 PMCID: PMC2427357 DOI: 10.1074/jbc.m800109200] [Citation(s) in RCA: 330] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Revised: 04/24/2008] [Indexed: 01/06/2023] Open
Abstract
Hyaluronan (HA) is a major glycosaminoglycan in the extracellular matrix whose expression is tightly linked to multidrug resistance and tumor progression. In this study we investigated HA-induced interaction between CD44 (a HA receptor) and Nanog (an embryonic stem cell transcription factor) in both human breast tumor cells (MCF-7 cells) and human ovarian tumor cells (SK-OV-3.ipl cells). Using a specific primer pair to amplify Nanog by reverse transcriptase-PCR, we detected the expression of Nanog transcript in both tumor cell lines. In addition, our results reveal that HA binding to these tumor cells promotes Nanog protein association with CD44 followed by Nanog activation and the expression of pluripotent stem cell regulators (e.g. Rex1 and Sox2). Nanog also forms a complex with the "signal transducer and activator of transcription protein 3" (Stat-3) in the nucleus leading to Stat-3-specific transcriptional activation and multidrug transporter, MDR1 (P-glycoprotein) gene expression. Furthermore, we observed that HA-CD44 interaction induces ankyrin (a cytoskeletal protein) binding to MDR1 resulting in the efflux of chemotherapeutic drugs (e.g. doxorubicin and paclitaxel (Taxol)) and chemoresistance in these tumor cells. Overexpression of Nanog by transfecting tumor cells with Nanog cDNA stimulates Stat-3 transcriptional activation, MDR1 overexpression, and multidrug resistance. Down regulation of Nanog signaling or ankyrin function (by transfecting tumor cells with Nanog small interfering RNA or ankyrin repeat domain cDNA) not only blocks HA/CD44-mediated tumor cell behaviors but also enhances chemosensitivity. Taken together, these findings suggest that targeting HA/CD44-mediated Nanog-Stat-3 signaling pathways and ankyrin/cytoskeleton function may represent a novel approach to overcome chemotherapy resistance in some breast and ovarian tumor cells displaying stem cell marker properties during tumor progression.
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Affiliation(s)
- Lilly Y W Bourguignon
- Department of Medicine, University of California, San Francisco, and Endocrine Unit, Veterans Affairs Medical Center, San Francisco, California 94121, USA.
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95
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STAT3 as a target for inducing apoptosis in solid and hematological tumors. Cell Res 2008; 18:254-67. [PMID: 18227858 DOI: 10.1038/cr.2008.18] [Citation(s) in RCA: 387] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Studies in the past few years have provided compelling evidence for the critical role of aberrant Signal Transducer and Activator of Transcription 3 (STAT3) in malignant transformation and tumorigenesis. Thus, it is now generally accepted that STAT3 is one of the critical players in human cancer formation and represents a valid target for novel anticancer drug design. This review focuses on aberrant STAT3 and its role in promoting tumor cell survival and supporting the malignant phenotype. A brief evaluation of the current strategies targeting STAT3 for the development of novel anticancer agents against human tumors harboring constitutively active STAT3 will also be presented.
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96
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Siddiquee KAZ, Gunning PT, Glenn M, Katt WP, Zhang S, Schroeck C, Sebti SM, Jove R, Hamilton AD, Turkson J, Turkson J. An oxazole-based small-molecule Stat3 inhibitor modulates Stat3 stability and processing and induces antitumor cell effects. ACS Chem Biol 2007; 2:787-98. [PMID: 18154266 DOI: 10.1021/cb7001973] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Stat3 is hyperactivated in many human tumors and represents a valid target for anticancer drug design. We present a novel small-molecule Stat3 inhibitor, S3I-M2001, and describe the dynamics of intracellular processing of activated Stat3 within the context of the biochemical and biological effects of the Stat3 inhibitor. S3I-M2001 is an oxazole-based peptidomimetic of the Stat3 Src homology (SH) 2 domain-binding phosphotyrosine peptide that selectively disrupts active Stat3:Stat3 dimers. Consequently, hyperactivated Stat3, which hitherto occurs as "dotlike" structures of nuclear bodies, undergoes an early aggregation into nonfunctional perinuclear aggresomes and a late-phase proteasome-mediated degradation in malignant cells treated with S3I-M2001. Thus, S3I-M2001 inhibited Stat3-dependent transcriptional regulation of tumor survival genes, such as Bcl-xL. Furthermore, Stat3-dependent malignant transformation, survival, and migration and invasion of mouse and human cancer cells harboring persistently activated Stat3 were inhibited by S3I-M2001. Finally, S3I-M2001 inhibited growth of human breast tumor xenografts. The study identifies a novel Stat3 inhibitor, S3I-M2001, with antitumor cell effects mediated in part through a biphasic loss of functional Stat3. The study represents the first on intracellular Stat3 stability and processing following inhibition by a small molecule that has significant antitumor activity.
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Affiliation(s)
- Khandaker A. Z. Siddiquee
- BioMolecular Science
Center and
- Department of Molecular Biology and Microbiology, University of Central Florida College of Medicine, Orlando, Florida 32826
| | | | - Matthew Glenn
- Department of Chemistry, Yale University, New Haven, Connecticut 06520
| | - William P. Katt
- Department of Chemistry, Yale University, New Haven, Connecticut 06520
| | | | | | - Said M. Sebti
- Drug Discovery Programs, H. Lee Moffitt Cancer Center and Research Institute and Departments of
- Interdisciplinary Oncology
- Biochemistry and Molecular Biology, University of South Florida College of Medicine, Tampa, Florida 33612
| | - Richard Jove
- Developmental Cancer Therapeutics Program, City of Hope Comprehensive Cancer Center, City of Hope, Duarte, California 91010
- Division of Molecular Medicine, Beckman Research Institute, City of Hope, Duarte, California 91010
| | | | - James Turkson
- BioMolecular Science
Center and
- Department of Molecular Biology and Microbiology, University of Central Florida College of Medicine, Orlando, Florida 32826
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97
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Nakagawa J, Nishitai G, Inageda K, Matsuoka M. Phosphorylation of Stats at Ser727 in renal proximal tubular epithelial cells exposed to cadmium. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2007; 24:252-259. [PMID: 21783819 DOI: 10.1016/j.etap.2007.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2007] [Revised: 06/02/2007] [Accepted: 06/10/2007] [Indexed: 05/31/2023]
Abstract
The effects of cadmium exposure on serine phosphorylation of signal transducers and activators of transcription (Stats) and an upstream kinase were examined in renal proximal tubular cells. In porcine LLC-PK1 cells treated with cadmium, Stat1 and Stat3 proteins were phosphorylated at Ser727 without changing total Stat protein levels. While phosphorylated forms of the members of mitogen-activated protein kinases (MAPKs) increased in response to cadmium exposure, treatment with a p38 inhibitor, SB203580 reduced Ser727 phosphorylation of Stat1 and Stat3 markedly in LLC-PK1 cells. The expression of human matrix metalloproteinase-3 (MMP-3), a Stats-inducible gene, was found to be up-regulated in human HK-2 cells exposed to cadmium, and suppressed by preincubation with SB203580. These results suggest that cadmium might induce the phosphorylation of Stat1 and Stat3 at Ser727 via the p38 pathway at least in part, and modulate gene expression in these proximal tubular cells.
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Affiliation(s)
- Junko Nakagawa
- Department of Hygiene and Public Health I, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan
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98
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Horie K, Ohashi M, Satoh Y, Sairenji T. The role of p38 mitogen-activated protein kinase in regulating interleukin-10 gene expression in Burkitt's lymphoma cell lines. Microbiol Immunol 2007; 51:149-61. [PMID: 17237610 DOI: 10.1111/j.1348-0421.2007.tb03885.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In malignant B lymphoma cells interleukin-10 (IL-10) expression is frequently upregulated. This effect is thought to support to the malignant transformation of these cells and to be a potential target for pharmacotherapy. To define better the mechanism for upregulation of the IL-10 gene, we tested the association between IL-10 and p38 mitogen-activated protein kinase (MAPK) in several Epstein-Barr virus (EBV) infected and non-infected Burkitt's lymphoma (BL) cell lines. The all BL cell lines expressed IL-10 and IL-10 receptor mRNAs, and produced IL-10. p38 MAPK was constitutively phosphorylated in the cytoplasm of the BL cell lines. We further analyzed molecular effects of p38 MAPK on IL-10 expression in Akata cells. Exogenous IL-10 lead rapidly to phosphorylation of Jak1 and Tyk2 as transducers of signals of IL-10, and promoted growth of Akata cells in a dose-dependent manner. The phosphorylation of cytoplasmic p38 MAPK in Akata cells was reduced by the serine/threonine kinase inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H7). A specific inhibitor of p38 MAPK, SB203580, blocked simultaneously STAT3 DNA-binding activity, and IL-10 mRNA expression, IL-10 production, and then the cell growth was inhibited. These results indicate that the p38 MAPK pathway is functionally linked to IL-10 gene expression and supports the view that the constitutive activation of cytoplasmic p38 MAPK in BL cells is a step in the upregulation of IL-10 gene expression and lymphomagenesis.
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Affiliation(s)
- Kazutaka Horie
- Division of Biosignaling, Department of Biomedical Sciences, School of Life Science, Faculty of Medicine, Tottori University, Japan
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Norkina O, Dolganiuc A, Shapiro T, Kodys K, Mandrekar P, Szabo G. Acute alcohol activates STAT3, AP-1, and Sp-1 transcription factors via the family of Src kinases to promote IL-10 production in human monocytes. J Leukoc Biol 2007; 82:752-62. [PMID: 17575268 DOI: 10.1189/jlb.0207099] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Alcohol consumption is associated with an imbalance in pro- and anti-inflammatory cytokines and immunosuppression, partially as a result of enhanced IL-10 production. The mechanisms of IL-10 induction by alcohol remain poorly understood. We identified that increased IL-10 production in human monocytes after acute in vivo alcohol consumption or in vitro alcohol treatment was associated with increased STAT3 activation. Alcohol alone induced and in combination with LPS augmented STAT3 phosphorylation at tyrosine 705 (tyr705) and serine 727 (ser727) residues and increased STAT3 binding to DNA. Upstream, alcohol activated the Src kinases, as indicated by an increase in phosphorylated and a decrease in nonphosphorylated Src proteins. STAT3 activation by Src kinases occurred directly at the tyr705 residue and indirectly at the ser727 residue via JNK MAPKs. Using specific Src (PP2), JNK1/2 (SB600125), or p38 (SB203580) inhibitors, we determined that alcohol treatment alone induced and together with LPS, augmented the DNA-binding capacity of the specificity protein-1 (Sp-1) and AP-1 transcription factors involved in IL-10 production via Src-mediated activation of p38 MAPK and JNK, respectively. Our data suggest that acute alcohol activates Src/STAT3 and Src/MAPK/STAT3, AP-1, and Sp-1 pathways as important mechanisms for IL-10-mediated immunomodulation after acute alcohol use.
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Affiliation(s)
- Oxana Norkina
- University of Massachusetts Medical School, Department of Medicine, LRB 215, 364 Plantation Street, Worcester, MA 01605, USA
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Zaheer S, Wu Y, Bassett J, Yang B, Zaheer A. Glia Maturation Factor Regulation of STAT Expression: A Novel Mechanism in Experimental Autoimmune Encephalomyelitis. Neurochem Res 2007; 32:2123-31. [PMID: 17551829 DOI: 10.1007/s11064-007-9383-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2007] [Accepted: 05/09/2007] [Indexed: 10/23/2022]
Abstract
Inflammatory cytokines are implemented in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. We previously demonstrated that glia maturation factor (GMF), a brain protein, isolated, sequenced and cloned in our laboratory, induce expression of proinflammatory cytokine/chemokine in the central nervous system (CNS). We found GMF-deficient (knockout) mice relatively resistant to EAE development after immunization with encephalitogenic MOG peptide 35-55. Consistent with these findings, the expression of proinflammatory cytokines in CNS of mice with EAE differed profoundly between wild type and GMF-knockout mice. In the present study we examined the expressions of six murine signal transducers and activators of transcription (STATs) genes, which are known to regulate the cytokine-dependent signal transduction pathways in autoimmune inflammation. The expressions of STATs genes were evaluated in the brains and spinal cords of wild type and GMF-knockout mice at the peak of EAE by quantitative real-time RT-PCR. Compared to GMF-knockout mice, the expressions of STAT1, STAT2, STAT3, STAT4, STAT5, and STAT6 genes were significantly (P < 0.001) upregulated in the wild type mice exhibiting EAE symptoms. The results are consistent with the diminished development of EAE in the GMF-knockout mice. A significant suppression of STATs expression in GMF-knockout mice suggests GMF as an upstream effector of JAK/STAT signaling.
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Affiliation(s)
- Smita Zaheer
- Veterans Affairs Medical Center, Iowa City, IA, USA.
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