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Shurin GV, Vats K, Kruglov O, Bunimovich YL, Shurin MR. Tumor-Induced T Cell Polarization by Schwann Cells. Cells 2022; 11:3541. [PMID: 36428970 PMCID: PMC9688729 DOI: 10.3390/cells11223541] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/03/2022] [Accepted: 11/05/2022] [Indexed: 11/12/2022] Open
Abstract
Nerve-cancer crosstalk resulting in either tumor neurogenesis or intratumoral neurodegeneration is critically controlled by Schwann cells, the principal glial cells of the peripheral nervous system. Though the direct stimulating effect of Schwann cells on malignant cell proliferation, motility, epithelial-mesenchymal transition, and the formation of metastases have been intensively investigated, the ability of Schwann cells to affect the effector and regulatory immune cells in the tumor environment is significantly less studied. Here, we demonstrated that tumor cells could stimulate Schwann cells to produce high levels of prostaglandin E, which could be blocked by COX-2 inhibitors. This effect was mediated by tumor-derived TGF-β as neutralization of this cytokine in the tumor-conditioned medium completely blocked the inducible prostaglandin E production by Schwann cells. Similar protective effects were also induced by the Schwann cell pretreatment with TGF-βR1/ALK4/5/7 and MAPK/ERK kinase inhibitors of the canonical and non-canonical TGF-β signaling pathways, respectively. Furthermore, prostaglandin E derived from tumor-activated Schwann cells blocked the proliferation of CD3/CD28-activated T cells and upregulated the expression of CD73 and PD-1 on both CD4+ and CD8+ T cells, suggesting T cell polarization to the exhausted phenotype. This new pathway of tumor-induced T cell inhibition via the activation of neuroglial cells represents new evidence of the importance of nerve-cancer crosstalk in controlling tumor development and progression. A better understanding of the tumor-neuro-immune axis supports the development of efficient targets for harnessing this axis and improving the efficacy of cancer therapy.
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Affiliation(s)
- Galina V. Shurin
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA 15261, USA
| | - Kavita Vats
- Department of Dermatology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - Oleg Kruglov
- Department of Dermatology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - Yuri L. Bunimovich
- Department of Dermatology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - Michael R. Shurin
- Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, PA 15261, USA
- Department of Immunology, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
- Clinical Immunopathology UPMC, CLB, Room 4024, 3477 Euler Way, Pittsburgh, PA 15213, USA
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Ogazon del Toro A, Jimenez L, Serrano Rubi M, Castillo A, Hinojosa L, Martinez Rendon J, Cereijido M, Ponce A. Prostaglandin E2 Enhances Gap Junctional Intercellular Communication in Clonal Epithelial Cells. Int J Mol Sci 2021; 22:5813. [PMID: 34071686 PMCID: PMC8198183 DOI: 10.3390/ijms22115813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/30/2021] [Accepted: 03/30/2021] [Indexed: 12/12/2022] Open
Abstract
Prostaglandins are a group of lipids that produce diverse physiological and pathological effects. Among them, prostaglandin E2 (PGE2) stands out for the wide variety of functions in which it participates. To date, there is little information about the influence of PGE2 on gap junctional intercellular communication (GJIC) in any type of tissue, including epithelia. In this work, we set out to determine whether PGE2 influences GJIC in epithelial cells (MDCK cells). To this end, we performed dye (Lucifer yellow) transfer assays to compare GJIC of MDCK cells treated with PGE2 and untreated cells. Our results indicated that (1) PGE2 induces a statistically significant increase in GJIC from 100 nM and from 15 min after its addition to the medium, (2) such effect does not require the synthesis of new mRNA or proteins subunits but rather trafficking of subunits already synthesized, and (3) such effect is mediated by the E2 receptor, which, in turn, triggers a signaling pathway that includes activation of adenylyl cyclase and protein kinase A (PKA). These results widen the knowledge regarding modulation of gap junctional intercellular communication by prostaglandins.
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Affiliation(s)
| | | | | | | | | | | | | | - Arturo Ponce
- Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN, CDMX, México C.P. 07360, Mexico; (A.O.d.T.); (L.J.); (M.S.R.); (A.C.); (L.H.); (J.M.R.); (M.C.)
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3
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Zaiss AK, Zuber J, Chu C, Machado HB, Jiao J, Catapang AB, Ishikawa TO, Gil JS, Lowe SW, Herschman HR. Reversible suppression of cyclooxygenase 2 (COX-2) expression in vivo by inducible RNA interference. PLoS One 2014; 9:e101263. [PMID: 24988319 PMCID: PMC4079684 DOI: 10.1371/journal.pone.0101263] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 06/04/2014] [Indexed: 12/11/2022] Open
Abstract
Prostaglandin-endoperoxide synthase 2 (PTGS2), also known as cyclooxygenase 2 (COX-2), plays a critical role in many normal physiological functions and modulates a variety of pathological conditions. The ability to turn endogenous COX-2 on and off in a reversible fashion, at specific times and in specific cell types, would be a powerful tool in determining its role in many contexts. To achieve this goal, we took advantage of a recently developed RNA interference system in mice. An shRNA targeting the Cox2 mRNA 3′untranslated region was inserted into a microRNA expression cassette, under the control of a tetracycline response element (TRE) promoter. Transgenic mice containing the COX-2-shRNA were crossed with mice encoding a CAG promoter-driven reverse tetracycline transactivator, which activates the TRE promoter in the presence of tetracycline/doxycycline. To facilitate testing the system, we generated a knockin reporter mouse in which the firefly luciferase gene replaces the Cox2 coding region. Cox2 promoter activation in cultured cells from triple transgenic mice containing the luciferase allele, the shRNA and the transactivator transgene resulted in robust luciferase and COX-2 expression that was reversibly down-regulated by doxycycline administration. In vivo, using a skin inflammation-model, both luciferase and COX-2 expression were inhibited over 80% in mice that received doxycycline in their diet, leading to a significant reduction of infiltrating leukocytes. In summary, using inducible RNA interference to target COX-2 expression, we demonstrate potent, reversible Cox2 gene silencing in vivo. This system should provide a valuable tool to analyze cell type-specific roles for COX-2.
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Affiliation(s)
- Anne K. Zaiss
- Department of Medical and Molecular Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Johannes Zuber
- Cold Spring Harbor Laboratory and Howard Hughes Medical Institute, New York, New York, United States of America
| | - Chun Chu
- Department of Medical and Molecular Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Hidevaldo B. Machado
- Department of Medical and Molecular Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jing Jiao
- Department of Medical and Molecular Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Arthur B. Catapang
- Department of Medical and Molecular Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Tomo-o Ishikawa
- Department of Medical and Molecular Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Jose S. Gil
- Department of Medical and Molecular Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
| | - Scott W. Lowe
- Cold Spring Harbor Laboratory and Howard Hughes Medical Institute, New York, New York, United States of America
| | - Harvey R. Herschman
- Department of Medical and Molecular Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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4
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Eilati E, Hales K, Zhuge Y, Fricano KA, Yu R, van Breemen RB, Hales DB. Flaxseed enriched diet-mediated reduction in ovarian cancer severity is correlated to the reduction of prostaglandin E(2) in laying hen ovaries. Prostaglandins Leukot Essent Fatty Acids 2013; 89:179-87. [PMID: 23978451 PMCID: PMC3811136 DOI: 10.1016/j.plefa.2013.08.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 07/31/2013] [Accepted: 08/02/2013] [Indexed: 12/31/2022]
Abstract
Prevention of ovarian cancer is the best approach for reducing the impact of this deadly disease. The laying hen is a robust model of spontaneous ovarian cancer that recapitulates the human disease. Dietary intervention with flaxseed, the richest vegetable source of omega-3 fatty acids (OM-3FAs) and phytoestrogen lignans, demonstrate the potential for effective prevention and amelioration of ovarian cancer by targeting inflammatory prostaglandin pathways. Prostaglandin E2 (PGE2) is the most pro-inflammatory ecoisanoid and one of the downstream products of two isoforms of cyclooxygenase (COX) enzymes: COX-1 and COX-2. Our objective was to investigate the effect of flaxseed supplementation for one year on ovarian cancer and correlate its effects to expression of COX enzymes and concentrations of prostaglandins. White Leghorn hens were fed 10% flaxseed-enriched or standard diet for one year. The severity of ovarian cancer was determined by gross pathology and histology. COX-1 and COX-2 localization and protein and mRNA expression and PGE2 and PGE3 concentrations in ovaries were measured by IHC, western blot, quantitative real-time PCR and LC-MS-MS, respectively. The results demonstrated a significant reduction in late stage ovarian tumors in the flaxseed-fed hens compared with the control diet-fed hens. In correlation with decreased ovarian cancer severity, concentrations of PGE2 and expression of COX-2 were diminished in ovaries of flaxseed-fed hens. PGE3 concentrations were below the level of detection. The results demonstrated that in normal ovaries, COX-1 was localized to the granulosa cell layer surrounding the follicles and ovarian surface epithelium (OSE) whereas COX-2 protein was localized to the granulosa cell layer in the follicle. Extensive COX-1 and COX-2 protein expression was found throughout the ovarian carcinoma. Our findings suggest that the flaxseed-mediated reduction in the severity of ovarian cancer in hens is correlated to the reduction in PGE2 in the ovaries of flaxseed-fed hens. These findings may provide the basis for clinical trials of dietary intervention targeting prostaglandin biosynthesis for the prevention and treatment of ovarian cancer.
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Affiliation(s)
- Erfan Eilati
- Department of Physiology, Southern Illinois University at Carbondale, School of Medicine, Carbondale, IL, USA
| | - Karen Hales
- Department of Physiology, Southern Illinois University at Carbondale, School of Medicine, Carbondale, IL, USA
| | - Yan Zhuge
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, USA
| | | | - Rui Yu
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, Chicago, IL, USA
| | - Richard B. van Breemen
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, Chicago, IL, USA
| | - Dale Buchanan Hales
- Department of Physiology, Southern Illinois University at Carbondale, School of Medicine, Carbondale, IL, USA
- Corresponding author. Tel.: +1618 453 1544; fax: +1618 453 1517.
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Sticozzi C, Belmonte G, Cervellati F, Di Capua A, Maioli E, Cappelli A, Giordani A, Biava M, Anzini M, Valacchi G. Antiproliferative effect of two novel COX-2 inhibitors on human keratinocytes. Eur J Pharm Sci 2013; 49:133-41. [PMID: 23454135 DOI: 10.1016/j.ejps.2013.02.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/28/2013] [Accepted: 02/08/2013] [Indexed: 11/25/2022]
Abstract
Selective COX-2 inhibitors (COXib) belonging to the class of diaryl heterocycles (e.g., celecoxib, rofecoxib, etc.), are devoid of the undesirable effects due to their capacity to inhibit selectively inducible (COX-2), responsible for inflammatory effects but not constitutive cyclooxygenase-1 (COX-1)(COX); responsible for cytoprotective effects on gastric mucosa. In addition, several reports have identified an increased risk of cardiovascular events associated with the use of COXib. We have developed a new series of anti-inflammatory agents (1,5-diarylpyrrole-3-alkoxyethyl esters and ethers). To evaluate the effect of two 1,5-diarylpyrrole-3-alkoxyethyl ethers, VA441 and VA428 (up to 100 μM), respectively, in comparison with two well known COXib, celecoxib and rofecoxib, on HaCaT cell (keratinocytes) proliferation and toxicity. Crucial molecules in cell cycle progression, i.e. NFκB and ERK as targets/mediators and cyclin D1 and p21 Cip1/Kip as final effectors were evaluated by Western blot, immunohystochemistry and q-PCR analysis. Both compounds, VA441 and VA428, showed a strong inhibition of cell proliferation, and did not exhibit cytotoxicity. The anti-proliferative effect was accompanied by a strong activation of ERK and induction of the cell cycle inhibitor p21. In addition, there was a clear inhibition of the transcription factor NF-κB and downregulation of cyclin D1, with enforced inhibition of the HaCaT cell cycle progression. These data suggest that compounds VA441 and VA428, along with their role in inhibiting COX-2 and inflammation, could have a possible therapeutic (topical and systemic) use against skin proliferative disorders, such as psoriasis.
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Affiliation(s)
- Claudia Sticozzi
- Dipartimento di Scienze della Vita e Biotecnologie, Università degli Studi di Ferrara, Via L. Borsari 46, 44100 Ferrara, Italy
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6
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Eilati E, Pan L, Bahr JM, Hales DB. Age dependent increase in prostaglandin pathway coincides with onset of ovarian cancer in laying hens. Prostaglandins Leukot Essent Fatty Acids 2012; 87:177-84. [PMID: 23089186 PMCID: PMC3592969 DOI: 10.1016/j.plefa.2012.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 09/04/2012] [Accepted: 09/05/2012] [Indexed: 01/01/2023]
Abstract
Chronic inflammation has been linked to cancer. Prostaglandin E₂ (PGE₂) is the most pro-inflammatory lipid and one of the downstream products of 2 isoforms of cyclooxygenase (COX) enzymes: COX-1 and COX-2. Ovarian cancer is the most lethal gynecological malignancy and mainly occurs in older women. The factors that contribute to the correlation of age and ovarian cancer are unknown. The purpose of this study was to examine the expression of COX enzymes and PGE₂ levels in ovaries and correlate them to ovarian cancer and aging. White Leghorn hens aged 1, 1.5, 2, 2.5, 3 and 3.5 years were used. The incidence of ovarian cancer was determined by gross pathology and histology. COX-1 and COX-2 protein and mRNA expression and PGE₂ concentrations in ovaries were measured using Western blot, quantitative real-time PCR and ELISA, respectively. Our results indicated an increase in ovarian cancer incidence and expression of both COX enzymes in ovaries of older hens. In correlation with ovarian cancer incidence and COX enzymes expression, PGE₂ concentrations were elevated with age. Ovaries with tumor had elevated COX-1 expression and PGE₂ concentration compared to normal ovaries. Our findings suggest that the up-regulation of COX enzymes with age is the main contributing factor in the age associated increase in PGE₂. Furthermore, elevated PGE₂ in ovaries of hens concomitant with age suggests its important role in early stages of ovarian carcinogenesis. These finding may provide the basis for clinical trials utilizing COX specific inhibitors or dietary intervention targeting prostaglandin biosynthesis for the prevention and treatment of ovarian cancer.
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Affiliation(s)
- Erfan Eilati
- Department of Physiology, Southern Illinois University—Carbondale, School of Medicine, Carbondale, IL 62901, USA
| | - Lurui Pan
- Department of Physiology, Southern Illinois University—Carbondale, School of Medicine, Carbondale, IL 62901, USA
| | - Janice M. Bahr
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, 1207 W. Gregory Dr., Urbana, IL, USA
| | - Dale Buchanan Hales
- Department of Physiology, Southern Illinois University—Carbondale, School of Medicine, Carbondale, IL 62901, USA
- Correspondence to: Department of Physiology, Southern Illinois University Carbondale, School of Medicine, Life Science II, Room 250 (M/C 6512), 1125 Lincoln Drive, Carbondale, IL 62901, USA. Tel.: +1 618 453 1544; fax: +1 618 453 1517. (D.B. Hales)
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7
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Abstract
Cyclooxygenase-2 (COX-2) is an enzyme induced in response to multiple mitogenic and inflammatory stimuli, including UV light. UV-induced COX-2 expression induces production of prostaglandin E2 (PGE2) in keratinocytes, which mediates inflammation and cell proliferation. Until recently, studies regarding COX-2 and PGE2 in the skin have focused on keratinocytes and skin cancer and the effect of PGs produced by keratinocytes on melanocytes. However, the effects of COX-2 itself or COX-2 inhibitors on melanogenesis are not well known. Therefore, to establish the role of COX-2 in melanogenesis, we investigated the effects of knock-down of COX-2 in melanocytes on melanin production and the expression of melanogenic molecules through silencing of COX-2 expression with COX-2 short interfering RNA (siRNA). COX-2 knock-down in melanocytes decreased the expressions of tyrosinase, TRP-1, TRP-2, gp100 and MITF and also reduced tyrosinase enzyme activity. Furthermore, COX-2 siRNA-transfected melanocytes showed markedly reduced alpha-melanocyte stimulating hormone (α-MSH)-induced melanin production. In addition, α-MSH-induced COX-2 expression in both scrambled siRNA-transfected and COX-2 siRNA-transfected melanocytes was greater than α-MSH-untreated cells. Our results suggest that COX-2 might be a candidate target for the development of anti-melanogenic agents and α-MSH-induced pigmentation could be closely associated with COX-2 expression. COX-2 inhibitors might therefore be of particular use in whitening cosmetics for hyperpigmentation disorders such as melasma, postinflammatory hyperpigmentation and solar lentigo.
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Affiliation(s)
- Ji Y Kim
- Department of Dermatology & Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea
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8
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Gomez-Lira M, Tessari G, Mazzola S, Malerba G, Rugiu C, Naldi L, Nacchia F, Valerio F, Anna B, Forni A, Boschiero L, Sandrini S, Faggian G, Girolomoni G, Turco A. Analysis of the 3'UTR of the prostaglandin synthetase-2 (PTGS-2/COX-2) gene in non-melanoma skin cancer after organ transplantation. Exp Dermatol 2011; 20:1025-7. [PMID: 21995456 DOI: 10.1111/j.1600-0625.2011.01381.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
To define the potential involvement of polymorphisms in the 3'untranslated region (3'UTR) of the prostaglandin synthetase-2 (PTGS-2) gene to non-melanoma skin cancer (NMSC) predisposition after transplantation, we screened for genetic variant, relevant parts of this region. It contains binding sites for trans-acting factors, an alternative polyadenylation site and putative target sequences for miRNAs. Variant +8473T>C did not appear to play a functional role in the regulation of gene expression in human keratinocyte-transfected cells. In addition to the well-known +8473T>C, we identified four polymorphisms: +8293G>C, +10259T>G, +10267G>A and +10335G>A. No allele frequency differences were observed between cases and controls neither for +8473T>C nor for any of the identified polymorphisms, suggesting that polymorphisms in the 3'UTR of the PTGS2 gene are rare and unlikely to represent risk factor for NMSC after transplantation.
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Starner RJ, McClelland L, Abdel-Malek Z, Fricke A, Scott G. PGE(2) is a UVR-inducible autocrine factor for human melanocytes that stimulates tyrosinase activation. Exp Dermatol 2010; 19:682-4. [PMID: 20500768 DOI: 10.1111/j.1600-0625.2010.01074.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Prostaglandins activate signalling pathways involved in growth, differentiation and apoptosis. Prostaglandin E(2) (PGE(2)) is released by keratinocytes following ultraviolet irradiation (UVR) and stimulates the formation of dendrites in melanocytes. We show that multiple irradiations of human melanocytes with UVR-activated cPLA(2), the rate-limiting enzyme in eicosanoid synthesis and stimulated PGE(2) secretion. PGE(2) increased cAMP production, tyrosinase activity and proliferation in melanocytes. PGE(2) binds to four distinct G-protein coupled receptors (EP(1-4)). We show that PGE(2) stimulates EP(4) receptor signalling in melanocytes, resulting in cAMP production. Conversely, PGE(2) also stimulated the EP(3) receptor in melanocytes, resulting in lowered basal cAMP levels. These data suggest that relative levels or activity of these receptors controls effects of PGE(2) on cAMP in melanocytes. The data are the first to identify PGE(2) as an UVR-inducible autocrine factor for melanocytes. These data also show that PGE(2) activates EP(3) and EP(4) receptor signalling, resulting in opposing effects on cAMP production, a critical signalling pathway that regulates proliferation and melanogenesis in melanocytes.
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Choi EM, Kim GH, Lee YS. Atractylodes japonica
root extract protects osteoblastic MC3T3-E1 cells against hydrogen peroxide-induced inhibition of osteoblastic differentiation. Phytother Res 2009; 23:1537-42. [DOI: 10.1002/ptr.2813] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
Although prostaglandin E2 (PGE2) has been shown by pharmacologic and genetic studies to be important in skin cancer, the molecular mechanism(s) by which it contributes to tumor growth is not well understood. In this study, we investigated the mechanisms by which PGE2 stimulates murine keratinocyte proliferation using in vitro and in vivo models. In primary mouse keratinocyte cultures, PGE2 activated the epidermal growth factor receptor (EGFR) and its downstream signaling pathways as well as increased cyclic AMP (cAMP) production and activated the cAMP response element binding protein (CREB). EGFR activation was not significantly inhibited by pretreatment with a c-src inhibitor (PP2), nor by a protein kinase A inhibitor (H-89). However, PGE2-stimulated extracellularly regulated kinase 1/2 (ERK1/2) activation was completely blocked by EGFR, ERK1/2, and phosphatidylinositol 3-kinase (PI3K) pathway inhibitors. In addition, these inhibitors attenuated the PGE2-induced proliferation, nuclear factor-kappa B, activator protein-1 (AP-1), and CREB binding to the promoter regions of the cyclin D1 and vascular endothelial growth factor (VEGF) genes and expression of cyclin D1 and VEGF in primary mouse keratinocytes. Similarly, in vivo, we found that WT mice treated with PGE2 and untreated cyclooxygenase-2-overexpressing transgenic mice had higher levels of cell proliferation and expression of cyclin D1 and VEGF, as well as higher levels of activated EGFR, nuclear factor-kappa B, AP-1, and CREB, than vehicle-treated WT mice. Our findings provide evidence for a link between cyclooxygenase-2 overexpression and EGFR-, ERK-, PI3K-, cAMP-mediated cell proliferation, and the tumor-promoting activity of PGE2 in mouse skin.
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Affiliation(s)
- Kausar M Ansari
- Science Park-Research Division, The University of Texas M D Anderson Cancer Center, PO Box 389, Smithville, TX 78957, USA
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12
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Scott G, Fricke A, Fender A, McClelland L, Jacobs S. Prostaglandin E2 regulates melanocyte dendrite formation through activation of PKCzeta. Exp Cell Res 2007; 313:3840-50. [PMID: 17850789 PMCID: PMC2330264 DOI: 10.1016/j.yexcr.2007.07.039] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2007] [Revised: 07/05/2007] [Accepted: 07/30/2007] [Indexed: 12/11/2022]
Abstract
Prostaglandins are lipid signaling intermediates released by keratinocytes in response to ultraviolet irradiation (UVR) in the skin. The main prostaglandin released following UVR is PGE(2), a ligand for 4 related G-protein-coupled receptors (EP(1), EP(2), EP(3) and EP(4)). Our previous work established that PGE(2) stimulates melanocyte dendrite formation through activation of the EP(1) and EP(3) receptors. The purpose of the present report is to define the signaling intermediates involved in EP(1)- and EP(3)-dependent dendrite formation in human melanocytes. We recently showed that activation of the atypical PKCzeta isoform stimulates melanocyte dendricity in response to treatment with lysophosphatidylcholine. We therefore examined the potential contribution of PKCzeta activation on EP(1)- and EP(3)-dependent dendrite formation in melanocytes. Stimulation of the EP(1) and EP(3) receptors by selective agonists activated PKCzeta, and inhibition of PKCzeta activation abrogated EP(1)- and EP(3)-receptor-mediated melanocyte dendricity. Because of the importance of Rho-GTP binding proteins in the regulation of melanocyte dendricity, we also examined the effect of EP(1) and EP(3) receptor activation on Rac and Rho activity. Neither Rac nor Rho was activated upon treatment with EP(1,3)-receptor agonists. We show that melanocytes express only the EP(3A1) isoform, but not the EP(3B) receptor isoform, previously associated with Rho activation, consistent with a lack of Rho stimulation by EP(3) agonists. Our data suggest that PKCzeta activation plays a predominant role in regulation of PGE(2)-dependent melanocyte dendricity.
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Affiliation(s)
- Glynis Scott
- Department of Dermatology, University of Rochester School of Medicine, Rochester, NY 14642, USA.
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13
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Abstract
The cyclooxygenases (COX-1 and COX-2) and the prostaglandins (PGs) they generate play a major role in the skin's response to sunlight. Sunlight, especially the ultraviolet B (UVB) component, induces COX-2 and increases PG levels. However, PGs can have both beneficial and adverse cutaneous effects. To elucidate the roles of the COXs and the PGs they generate in response to UVB exposure, experiments with the COX-1- and COX-2-deficient mice have provided insight into the specific roles of each isoform. Furthermore, because PGE(2) is the major PG produced following UV exposure and PGE(2) manifests its biological activity via four membrane receptors (EP1, EP2, EP3, EP4), elucidating contributions of these receptors is essential for understanding the roles of PGs in UVB-induced effects. In this review, we summarize recent findings from the COX-deficient mice showing how COX-2 generated PGE(2) acting via the receptors EP2 and EP4 could contribute to short term beneficial, but also contribute to long-term carcinogenic effects in response to UVB exposure.
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Affiliation(s)
- Kyung-Soo Chun
- Laboratory of Molecular Carcinogenesis, NIEHS, NIH, Research Triangle Park, North Carolina 27709, USA
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Urick ME, Johnson PA. Cyclooxygenase 1 and 2 mRNA and protein expression in the Gallus domesticus model of ovarian cancer. Gynecol Oncol 2006; 103:673-8. [PMID: 16797680 DOI: 10.1016/j.ygyno.2006.05.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2006] [Revised: 04/20/2006] [Accepted: 05/03/2006] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Our purpose was to determine the mRNA and protein expression of cyclooxygenase 1 (COX-1) and cyclooxygenase 2 (COX-2) in ovarian tumors and normal ovaries of the hen, which is an excellent model for human ovarian cancer. Tissue concentrations of prostaglandin E(2) (PGE2) and PGE2 metabolites were also determined. METHODS Tissue was obtained from ovarian tumor (n = 18) and normal ovary (n = 29) of 2- to 4-year old Single-comb White Leghorn hens. Quantitative real-time PCR with Sybr Green was used to quantify the mRNA expression of COX-1 and COX-2, using 18S expression as an internal control for COX normalization. Immunohistochemistry using antibodies for COX-1 and COX-2 was used to localize protein expression of each isoform in a subset of tumor (n = 5) and normal samples (n = 6). For determination of tissue prostaglandin concentration, tissue was obtained from ovarian tumor (n = 8) and normal ovary (n = 8). PGE2 and PGE2 metabolites were measured using competitive enzyme immunoassays (EIAs). RESULTS Our results indicate that COX-1 mRNA expression is significantly higher (P < 0.05) in ovarian tumor samples compared to normal ovaries while there is no significant difference in expression of COX-2 between the samples. Immunohistochemistry results support this finding and show COX-1 expression only in tumor samples and COX-2 expression unchanged between normal ovary and tumor samples. PGE2 levels are significantly higher (P < 0.05) in tumor samples compared to normal ovaries, and there is no significant difference in PGE2 metabolite levels between the samples. CONCLUSION These findings may implicate COX-1 as a suitable target for the prevention or treatment of ovarian cancer.
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Affiliation(s)
- M E Urick
- Department of Animal Science, Cornell University, Ithaca, NY 14853, USA
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Akhgari A, Afrasiabi Garekani H, Sadeghi F, Azimaie M. Statistical optimization of indomethacin pellets coated with pH-dependent methacrylic polymers for possible colonic drug delivery. Int J Pharm 2005; 305:22-30. [PMID: 16236475 DOI: 10.1016/j.ijpharm.2005.08.025] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Revised: 05/13/2005] [Accepted: 08/17/2005] [Indexed: 10/25/2022]
Abstract
The objective of this study was to evaluate the effect of two factors (ratio of Eudragit S100 and Eudragit L100 and the coating level) on indomethacin release from pellets in order to optimize coating formulations for colonic delivery. Coating formulations were designed based on the full factorial design. Two independent variables were the ratio of Eudragit S100:Eudragit L100 (1:4, 1:1 and 1:0) and the level of coating (10%, 15% and 20%, w/w), respectively. The evaluated responses were lag time prior to drug release at pH 6.8 (the time required for drug release up to 2%) and percent of drug release at pH 6.8 in 5h. Polymers were coated onto the pellets containing 20% (w/w) indomethacin, using a fluidized bed coating apparatus. Dissolution test was carried out in media with different pH (1.2, 6.5, 6.8 and 7.2). The dissolution data revealed that the level of coating and the ratio of polymers are very important to achieve optimum formulation. Using responses and resulted statistical equations, optimum formulation consisted of Eudragit S100:L100 in 4:1 ratio and the level of coating (20%) was predicted. Practical results showed that the pellets prepared according to above formulation released no indomethacin at pH 1.2 (simulating stomach pH) and pH 6.5 (simulating proximal part of small intestine pH); drug release was slowly at pH 6.8 (simulating lower part of small intestine pH), but it was fast at pH 7.2 (simulating terminal ileum pH). The results of this study revealed that factorial design is a suitable tool for optimization of coating formulations to achieve colon delivery. It was shown that coating formulation consisted of Eudragit S100:Eudragit L100 in 4:1 ratio at 20% coating level has potential for colonic delivery of indomethacin loaded pellets. The optimized formulation produced dissolution profiles that were close to predicted values.
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Affiliation(s)
- A Akhgari
- School of Pharmacy and Pharmaceutical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
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Muriel M, Antequera M, Petrón M, Andrés A, Ruiz J. Stereospecific analysis of fresh and dry-cured muscle phospholipids from Iberian pigs. Food Chem 2005; 90:437-43. [DOI: 10.1016/j.foodchem.2004.05.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Lee HY, Suh YA, Kosmeder JW, Pezzuto JM, Hong WK, Kurie JM. Deguelin-Induced Inhibition of Cyclooxygenase-2 Expression in Human Bronchial Epithelial Cells. Clin Cancer Res 2004; 10:1074-9. [PMID: 14871987 DOI: 10.1158/1078-0432.ccr-0833-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The increased expression of cyclooxygenase (COX)-2 significantly enhances carcinogenesis and inflammatory reactions, and its regulation may be a reasonable target for cancer chemoprevention. We demonstrated previously that deguelin inhibits proliferation of premalignant human bronchial epithelial (HBE) cells, such as 1799 cells and squamous HBE cells, by regulating phosphatidylinositol-3-kinase Akt activity, which is involved in COX-2 expression. We sought to determine the effect of deguelin on COX-2 expression in squamous HBE cells. Deguelin strongly inhibited COX-2 expression in squamous HBE cells, without affecting the COX-1 protein level. Deguelin inhibited proliferation of a variety of non-small cell lung carcinoma (NSCLC) cell lines through apoptosis and induced Bax expression in the H322 NSCLC and squamous HBE cells. Deguelin treatment did not affect Bcl-2 protein levels but increased expression levels of the proapoptotic protein p53 and the cyclin-dependent kinase inhibitors p21 and p27 in the squamous HBE cells. The sensitivity of the squamous HBE and NSCLC cells to deguelin and the inhibitory effects of deguelin on COX-2 expression in the squamous HBE cells indicate that regulation of COX-2 expression is involved in the chemopreventive action of deguelin in lung cancer.
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Affiliation(s)
- Ho-Young Lee
- Department of Thoracic/Head and Neck Medical Oncology, Unit 432, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA.
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Moonen HJJ, Dommels YEM, van Zwam M, van Herwijnen MHM, Kleinjans JCS, Alink GM, de Kok TMCM. Effects of polyunsaturated fatty acids on prostaglandin synthesis and cyclooxygenase-mediated DNA adduct formation by heterocyclic aromatic amines in human adenocarcinoma colon cells. Mol Carcinog 2004; 40:180-8. [PMID: 15224350 DOI: 10.1002/mc.20032] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Dietary heterocyclic aromatic amines (HCA) and polyunsaturated fatty acids (PUFA) are both believed to play a role in colon carcinogenesis, and are both substrate for the enzyme cyclooxygenase (COX). In HCA-7 cells, highly expressing isoform COX-2, we investigated the effects of PUFA on prostaglandin synthesis and DNA adduct formation by the HCA 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3-methylimidazo[4,5-f]quinoline (IQ). Furthermore, we studied the role of COX, COX-2 in particular, and cytochrome P4501A2 (CYP1A2) by using the enzyme inhibitors indomethacin (IM), NS-398, and phenethyl isothiocyanate (PEITC), respectively. COX-mediated formation of prostaglandin E2 (PGE2) from linoleic acid (LA) showed that HCA-7 cells can convert LA into arachidonic acid (AA). Alternatively, eicosapentaenoic acid (EPA) was found to compete with AA for COX. Strongly decreased PGE2 levels by addition of IM demonstrated involvement of COX in PUFA metabolism. Both IM and NS-398 inhibited adduct formation by HCA to nearly the same extent, indicating involvement of COX-2 rather than COX-1, while CYP1A2 activity in HCA-7 cells was demonstrated by addition of PEITC. Overall, inhibiting effects were stronger for PhIP than for IQ. HCA-DNA adduct formation was stimulated by addition of PUFA, although high PUFA concentrations partly reduced this stimulating effect. Finally, similar effects for n-3 and n-6 fatty acids suggested that adduct formation may not be the crucial mechanism behind the differential effects of PUFA on colon carcinogenesis that have been described. These results show that COX, and COX-2 in particular, can play a substantial role in HCA activation, especially in extrahepatic tissues like the colon. Furthermore, the obvious interactions between PUFA and HCA in COX-2 expressing cancer cells may be important in modulating colorectal cancer risk.
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Affiliation(s)
- H J J Moonen
- Department of Health Risk Analysis and Toxicology, University of Maastricht, Maastricht, The Netherlands
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Thuillier P, Brash AR, Kehrer JP, Stimmel JB, Leesnitzer LM, Yang P, Newman RA, Fischer SM. Inhibition of peroxisome proliferator-activated receptor (PPAR)-mediated keratinocyte differentiation by lipoxygenase inhibitors. Biochem J 2002; 366:901-10. [PMID: 12069687 PMCID: PMC1222830 DOI: 10.1042/bj20020377] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2002] [Revised: 04/24/2002] [Accepted: 06/17/2002] [Indexed: 12/20/2022]
Abstract
Lipoxygenase (LOX) metabolites from arachidonic acid and linoleic acid have been implicated in atherosclerosis, inflammation, keratinocyte differentiation and tumour progression. We previously showed that peroxisome proliferator-activated receptors (PPARs) play a role in keratinocyte differentiation and that the PPARalpha ligand 8S-hydroxyeicosatetraenoic acid is important in this process. We hypothesized that blocking LOX activity would block PPAR-mediated keratinocyte differentiation. Three LOX inhibitors, nordihydroguaiaretic acid, quercetin and morin, were studied for their effects on primary keratinocyte differentiation and PPAR activity. All three LOX inhibitors blocked calcium-induced expression of the differentiation marker keratin 1. In addition, activity of a PPAR-responsive element was inhibited in the presence of all three inhibitors, and this effect was mediated primarily through PPARalpha and PPARgamma. LOX inhibitors decreased the activity of a chimaeric PPAR-Gal4-ligand-binding domain reporter system and this effect was reversed by addition of PPAR ligands. Ligand-binding studies revealed that the LOX inhibitors bind directly to PPARs and demonstrate a novel mechanism for these inhibitors in altering PPAR-mediated gene expression.
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Affiliation(s)
- Philippe Thuillier
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville 78957, USA
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Dommels YEM, Alink GM, van Bladeren PJ, van Ommen B. Dietary n-6 and n-3 polyunsaturated fatty acids and colorectal carcinogenesis: results from cultured colon cells, animal models and human studies. Environ Toxicol Pharmacol 2002; 11:297-308. [PMID: 21782613 DOI: 10.1016/s1382-6689(02)00006-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2001] [Revised: 12/18/2001] [Accepted: 01/11/2002] [Indexed: 05/31/2023]
Abstract
During the past few decades, many studies have been conducted to evaluate the effects of n-6 and n-3 polyunsaturated fatty acids (PUFAs) on colorectal carcinogenesis. This report provides a brief overview of the recent studies that have been performed in cultured colon cells, animal models as well as of the population-based and short-term biomarker studies with humans. No differential effect between n-6 and n-3 PUFAs has been observed in vitro. Results from animal models indicate that n-6 PUFAs have a tumor enhancing effect, predominantly during the post-initiation phase. n-3 PUFAs may protect against colorectal carcinogenesis during both the initiation and post-initiation phase. Population-based human studies show little or no associations between n-6 or n-3 PUFA intake and colorectal cancer. Short-term biomarker studies in humans suggest though that fish oil (FO) supplementation with high amounts of n-3 PUFAs may protect against colorectal carcinogenesis and that n-6 PUFA supplementation may increase the risk.
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Affiliation(s)
- Yvonne E M Dommels
- WUR/TNO Centre for Food Toxicology, The Netherlands; Toxicology Group, Division of Toxicology, Wageningen University, Tuinlaan 5, PO Box 8000, 6700 EA Wageningen, The Netherlands
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Affiliation(s)
- A J Johnson
- Division of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536-0082, USA
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Pestili de Almeida EM, Piché C, Sirois J, Doré M. Expression of cyclo-oxygenase-2 in naturally occurring squamous cell carcinomas in dogs. J Histochem Cytochem 2001; 49:867-75. [PMID: 11410611 DOI: 10.1177/002215540104900707] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Squamous cell carcinoma is one of the most common cancers in humans and is also a frequently diagnosed neoplasm in dogs. Induction of cyclo-oxygenase-2 (COX-2), a key rate-limiting enzyme in prostaglandin biosynthesis, has been implicated in the oncogenesis of various cancers in humans, including squamous cell carcinomas. However, expression of COX-2 has not been reported in spontaneous squamous cell carcinomas of non-human species. Canine squamous cell carcinomas share several similarities with the human disease. Therefore, the objective of this study was to determine whether COX isoenzymes were expressed in naturally occurring cases of squamous cell carcinomas in dogs. Canine normal skin (n=4) and squamous cell carcinomas (n=40) were studied by immunohistochemistry and immunoblotting analysis using polyclonal antibodies selective for COX-1 or COX-2. COX-2 was strongly expressed by neoplastic keratinocytes in all cases of squamous cell carcinomas, whereas no COX-2 was detected in normal skin and in the non-neoplastic skin and oral mucosa included in the tumor tissue samples (p<0.01). Immunoblotting analysis confirmed the restricted expression of COX-2 (72,000--74,000 molecular weight doublet) in squamous cell carcinomas only. In contrast, faint COX-1 staining was found in normal skin and in squamous cell carcinomas. This study demonstrates for the first time that COX-2 is induced in canine squamous cell carcinomas, and provides a new model to investigate the role and regulation of COX-2 gene expression in naturally occurring squamous cell carcinomas. (J Histochem Cytochem 49:867-875, 2001)
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Affiliation(s)
- E M Pestili de Almeida
- Département de Pathologie et Microbiologie, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada
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Wang HQ, Kim MP, Tiano HF, Langenbach R, Smart RC. Protein kinase C-alpha coordinately regulates cytosolic phospholipase A(2) activity and the expression of cyclooxygenase-2 through different mechanisms in mouse keratinocytes. Mol Pharmacol 2001; 59:860-6. [PMID: 11259631 DOI: 10.1124/mol.59.4.860] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Transgenic mice (K5-PKC alpha) in which the keratin 5 promoter directs the expression of protein kinase C-alpha (PKC alpha) to epidermal keratinocytes display a 10-fold increase in PKC alpha protein in their epidermis and alterations in phorbol ester-induced cutaneous inflammation [J Cell Science 1999;112:3497-3506]. In the current study, we have used these K5-PKC alpha mice to examine the role of PKC alpha in keratinocyte phospholipid metabolism/eicosanoid production and cutaneous inflammation. Primary keratinocytes from wild-type and transgenic mice were prelabeled in culture with [(3)H]arachidonic acid (AA) and subsequently treated with TPA. Compared with wild-type keratinocytes, K5-PKC alpha keratinocytes displayed a 2-fold increase in AA release. TPA treatment resulted in the phosphorylation of cPLA(2). PKC inhibitors GF-109203X or H7, but not mitogen-activated protein/extracellular signal-regulated protein kinase (MEK) inhibitor PD 98059, could inhibit phosphorylation and AA release. Topical 12-O-tetradecanoylphorbol-13-acetate (TPA) treatment of K5-PKC alpha mice resulted in a 5-fold increase in epidermal COX-2 induction and a 2- to 3-fold increase in prostaglandin (PG) E(2) levels above that observed in TPA-treated wild-type mice. PD 98059, GF-109203X, or H7 could block cyclooxygenase-2 (COX-2) induction by TPA. Because C/EBP beta, a basic leucine zipper transcription factor, can be activated via a PKC alpha/mitogen-activated protein kinase pathway and can influence COX-2 expression, we examined whether C/EBP beta is involved in TPA-induced epidermal COX-2 expression. TPA-induced COX-2 expression was similar in C/EBP beta nullizygous and wild-type mice. In summary, our results indicate that epidermal PKC alpha coordinately regulates cPLA(2) activity and COX-2 expression resulting in increased levels of AA and PGE(2). Furthermore, PKC alpha-induced AA release and cPLA(2) phosphorylation are independent of MEK, whereas PKC alpha-induced COX-2 expression and PGE(2) production are MEK-dependent and C/EBP beta-independent events.
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Affiliation(s)
- H Q Wang
- Cell Signaling and Cancer Group, Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, North Carolina 27695-7633, USA
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Abstract
The involvement of prostaglandins (PGs) and other eicosanoids in the development of human cancer has been known for over two decades. Importantly, an increase in PG synthesis may influence tumor growth in human beings and experimental animals, and numerous studies have illustrated the effect of PG synthesis on carcinogen metabolism, tumor cell proliferation and metastatic potential. PGs produced by cyclooxygenases (COXs) are represented by a large series of compounds that mainly enhance cancer development and progression, acting as carcinogens or tumor promoters, with profound effects on carcinogenesis. Further investigations suggest that arachidonic acid (AA) metabolites derived from lipoxygenase (LOX) pathways play an important role in growth-related signal transduction, implying that intervention through these pathways should be useful for arresting cancer progression. We discuss here the implications of COX and LOX in colon, pancreatic, breast, prostate, lung, skin, urinary bladder and liver cancers. Select inhibitors of COX and LOX are described, including nonsteroidal antiinflammatory drugs (NSAIDs), selective COX-2 inhibitors, curcumin, tea, silymarin and resveratrol, as well as a method useful for evaluating inhibitors of COX. Although a substantial amount of additional work is required to yield a better understanding of the role of COX and LOX in cancer chemoprevention, it is clear that beneficial therapeutic effects can be realized through drug-mediated modulation of these metabolic pathways.
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Affiliation(s)
- M Cuendet
- Department of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, and University of Illinois Cancer Center, University of Illinois at Chicago, 60612, USA
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Maldve RE, Kim Y, Muga SJ, Fischer SM. Prostaglandin E2 regulation of cyclooxygenase expression in keratinocytes is mediated via cyclic nucleotide-linked prostaglandin receptors. J Lipid Res 2000; 41:873-81. [DOI: 10.1016/s0022-2275(20)32029-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Hsu AL, Ching TT, Wang DS, Song X, Rangnekar VM, Chen CS. The cyclooxygenase-2 inhibitor celecoxib induces apoptosis by blocking Akt activation in human prostate cancer cells independently of Bcl-2. J Biol Chem 2000; 275:11397-403. [PMID: 10753955 DOI: 10.1074/jbc.275.15.11397] [Citation(s) in RCA: 532] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
This study investigates the apoptotic activity of the cyclooxygenase-2 (COX-2) inhibitor celecoxib in prostate carcinoma cells. COX-2 is constitutively expressed in androgen-responsive LNCaP and androgen-nonresponsive PC-3 cells. Exposure of these cells to celecoxib induces characteristic features of apoptosis, including morphological changes, DNA laddering, and caspase-3 activation, whereas piroxicam, a COX-1-specific inhibitor, displays no appreciable effect on either cancer cell line even after prolonged exposure. Moreover, the potency of celecoxib in apoptosis induction is significantly higher than that of other COX-2 inhibitors examined despite the observation that these inhibitors exhibit similar IC(50) in COX-2 inhibition. It is noteworthy that normal human prostate epithelial cells, expressing a marginally detectable level of COX-2, are insensitive to the induction of apoptosis by celecoxib. These data suggest a correlation between COX-2 expression and sensitivity to the apoptotic effect of the COX-2 inhibitor. In an effort to delineate the underlying mechanism, we examined the effect of celecoxib on the expression of Bcl-2 as well as the activation of the key anti-apoptotic kinase Akt. In contrast to an earlier report that attributed the apoptotic activity of NS398 in LNCaP cells to Bcl-2 down-regulation, we provide evidence that the induction of apoptosis by celecoxib in LNCaP and PC-3 cells is independent of Bcl-2. First, treatment with celecoxib does not alter the cellular Bcl-2 level in both cell lines. Second, enforced Bcl-2 expression in PC-3 cells does not confer protection against the induction of apoptosis by celecoxib. Our data show that celecoxib treatment blocks the phosphorylation of Akt. This correlation is supported by studies showing that overexpression of constitutively active Akt protects PC-3 cells from celecoxib-induced apoptosis. Nevertheless, how celecoxib down-regulates Akt is not clear because the drug does not adversely affect phosphoinositide 3-kinase activity in vivo and okadaic acid, a protein phosphatase 2A inhibitor, cannot rescue the inhibition. In summary, our data demonstrate that inhibition of Akt activation may play a crucial role in the induction of apoptosis by celecoxib.
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Affiliation(s)
- A L Hsu
- Division of Pharmaceutical Sciences, College of Pharmacy, Lexington, Kentucky 40536, USA
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Fischer SM, Lo HH, Gordon GB, Seibert K, Kelloff G, Lubet RA, Conti CJ. Chemopreventive activity of celecoxib, a specific cyclooxygenase-2 inhibitor, and indomethacin against ultraviolet light-induced skin carcinogenesis. Mol Carcinog 1999. [DOI: 10.1002/(sici)1098-2744(199908)25:4<231::aid-mc1>3.0.co;2-f] [Citation(s) in RCA: 307] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gonchar MV, Sergeeva MG, Namgaladze DA, Mevkh AT. Lack of direct connection between arachidonic acid release and prostanoid synthesis upon differentiation of U937 cell. Biochem Biophys Res Commun 1998; 249:829-32. [PMID: 9731221 DOI: 10.1006/bbrc.1998.9236] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The changes in AA incorporation and release as well as prostanoid synthesis upon differentiation of human premonocytic cell line, U937, induced by three functionally diverse agents--phorbol ester (TPA), dimethyl sulfoxide (DMSO), and retinoic acid (RA) have been investigated. The rate of AA incorporation into the cells remained unchanged whereas a 3- to 6-fold increase in AA release upon stimulation with Ca(2+)-ionophore A23187 as compared to undifferentiated cells was observed. While undifferentiated cells were incapable to metabolise AA via the cyclooxygenase pathway all three types of differentiated U937 cells produced TxB2 and PGE2. Only TPA-differentiated cells responded with a 6-fold increase of prostanoid synthesis after A23187 stimulation, whereas in DMSO-differentiated cells prostanoid synthesis was slightly stimulated by A23187 and in RA-differentiated cells it was not stimulated at all. Thus, agonist-induced prostanoid synthesis in differentiated cells is dependent on the nature of differentiating agent and does not correlate with AA liberation.
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Affiliation(s)
- M V Gonchar
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Russia
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