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Johnson MG, Konicke K, Kristianto J, Gustavson A, Garbo R, Wang X, Yuan B, Blank RD. Endothelin signaling regulates mineralization and posttranscriptionally regulates SOST in TMOb cells via miR 126-3p. Physiol Rep 2017; 5:5/4/e13088. [PMID: 28235973 PMCID: PMC5328763 DOI: 10.14814/phy2.13088] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 11/14/2016] [Accepted: 11/15/2016] [Indexed: 11/24/2022] Open
Abstract
Previously, our laboratory identified ECE‐1, encoding endothelin‐converting enzyme‐1 (ECE‐1), as a positional candidate for a pleiotropic quantitative trait locus affecting femoral size, shape, and biomechanical performance. We hypothesized that endothelin‐1 (ET‐1) signaling promotes osteogenesis. Exposure of immortalized mouse osteoblast (TMOb) cells to big ET‐1 increased mineralization. Following big ET‐1 treatment, we measured the secretion of insulin‐like‐growth factor‐1 (IGF1), dickkopf‐homolog‐1 protein 1 (DKK1), and sclerostin (SOST). In each case, big ET‐1 signaling changed secretion in a manner that favored increased osteogenic activity. Treatment with ECE‐1, endothelin receptor A (EDNRA), or WNT receptor antagonists inhibited the big ET‐1‐mediated increase in mineralization. In the presence of big ET‐1, message levels of Runx2, Igf1, Dkk1, and Sost are uncoupled from protein production, suggesting posttranscriptional regulation. To evaluate the role of big ET‐1 in normal bone physiology, we inhibited EDNRA signaling during mineralization in the absence of exogenous ET‐1. EDNRA blockade reduced mineralization, decreased IGF1, and increased DKK1 and SOST secretion, responses opposite to those induced by exogenous big ET‐1. Pharmacological and siRNA knockdown to inhibit ECE‐1 reduced mineralization and IGF1 secretion with decreasing DKK1 and decreasing or stable SOST secretion, suggesting a further, unknown role of ECE‐1 in osteoblast maturation. Previously we identified miR 126‐3p as a potential ET‐1‐responsive regulator of SOST in murine cells. Overexpression of miR126‐3p increased mineralization in TMOb cells and decreased SOST secretion. Osteoblasts express the ET‐1 signaling pathway and ET‐1 signaling is necessary for normal osteoblast differentiation and mineralization, acting through regulation of miRs that target osteogenic molecules.
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Affiliation(s)
- Michael G Johnson
- Geriatrics Research, Education and Clinical Center, William S. Middleton Veterans Affairs Hospital, Madison, Wisconsin .,Division of Endocrinology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Kathryn Konicke
- Medical Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin.,Division of Endocrinology, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Jasmin Kristianto
- Geriatrics Research, Education and Clinical Center, William S. Middleton Veterans Affairs Hospital, Madison, Wisconsin.,Division of Endocrinology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Anne Gustavson
- Geriatrics Research, Education and Clinical Center, William S. Middleton Veterans Affairs Hospital, Madison, Wisconsin.,Division of Endocrinology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Rachel Garbo
- Geriatrics Research, Education and Clinical Center, William S. Middleton Veterans Affairs Hospital, Madison, Wisconsin.,Division of Endocrinology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Xiaohu Wang
- Medical Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin.,Division of Endocrinology, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Baozhi Yuan
- Geriatrics Research, Education and Clinical Center, William S. Middleton Veterans Affairs Hospital, Madison, Wisconsin.,Division of Endocrinology, Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin
| | - Robert D Blank
- Geriatrics Research, Education and Clinical Center, William S. Middleton Veterans Affairs Hospital, Madison, Wisconsin.,Medical Service, Clement J. Zablocki Veterans Affairs Medical Center, Milwaukee, Wisconsin.,Division of Endocrinology, Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin
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A feed-forward regulation of endothelin receptors by c-Jun in human non-pigmented ciliary epithelial cells and retinal ganglion cells. PLoS One 2017; 12:e0185390. [PMID: 28938016 PMCID: PMC5609771 DOI: 10.1371/journal.pone.0185390] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 09/12/2017] [Indexed: 12/21/2022] Open
Abstract
c-Jun, c-Jun N-terminal kinase(JNK) and endothelin B (ETB) receptor have been shown to contribute to the pathogenesis of glaucoma. Previously, we reported that an increase of c-Jun and CCAAT/enhancer binding protein β (C/EBPβ) immunohistostaining is associated with upregulation of the ETB receptor within the ganglion cell layer of rats with elevated intraocular pressure (IOP). In addition, both transcription factors regulate the expression of the ETB receptor in human non-pigmented ciliary epithelial cells (HNPE). The current study addressed the mechanisms by which ET-1 produced upregulation of ET receptors in primary rat retinal ganglion cells (RGCs) and HNPE cells. Treatment of ET-1 and ET-3 increased the immunocytochemical staining of c-Jun and C/EBPβ in primary rat RGCs and co-localization of both transcription factors was observed. A marked increase in DNA binding activity of AP-1 and C/EBPβ as well as elevated protein levels of c-Jun and c-Jun-N-terminal kinase (JNK) were detected following ET-1 treatment in HNPE cells. Overexpression of ETA or ETB receptor promoted the upregulation of c-Jun and also elevated its promoter activity. In addition, upregulation of C/EBPβ augmented DNA binding and mRNA expression of c-Jun, and furthermore, the interaction of c-Jun and C/EBPβ was confirmed using co-immunoprecipitation. Apoptosis of HNPE cells was identified following ET-1 treatment, and overexpression of the ETA or ETB receptor produced enhanced apoptosis. ET-1 mediated upregulation of c-Jun and C/EBPβ and their interaction may represent a novel mechanism contributing to the regulation of endothelin receptor expression. Reciprocally, c-Jun was also found to regulate the ET receptors and C/EBPβ appeared to play a regulatory role in promoting expression of c-Jun. Taken together, the data suggests that ET-1 triggers the upregulation of c-Jun through both ETA and ETB receptors, and conversely c-Jun also upregulates endothelin receptor expression, thereby generating a positive feed-forward loop of endothelin receptor activation and expression. This feed-forward regulation may contribute to RGC death and astrocyte proliferation following ET-1 treatment.
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Endothelin-1 (ET-1) induces resistance to bortezomib in human multiple myeloma cells via a pathway involving the ETB receptor and upregulation of proteasomal activity. J Cancer Res Clin Oncol 2016; 142:2141-58. [PMID: 27530445 DOI: 10.1007/s00432-016-2216-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 08/04/2016] [Indexed: 01/24/2023]
Abstract
PURPOSE Bortezomib (BTZ) is used for the treatment of multiple myeloma (MM). However, a significant proportion of patients may be refractory to the drug. This study aimed to investigate whether the endothelin (ET-1) axis may act as an escape mechanism to treatment with bortezomib in MM cells. METHODS NCI-H929 and RPMI-8226 (human MM cell lines) were cultured with or without ET-1, BTZ, and inhibitors of the endothelin receptors. ET-1 levels were determined by ELISA, while the protein levels of its receptors and of the PI3K and MAPK pathways' components by western blot. Effects of ET-1 on cell proliferation were studied by MTT and on the ubiquitin proteasome pathway by assessing the chymotryptic activity of the 20S proteasome in cell lysates. RESULTS Endothelin receptors A and B (ETAR and ETBR, respectively) were found to be expressed in both cell lines, with the RPMI-8226 cells that are considered resistant to BTZ, expressing higher levels of ETBR and in addition secreting ET-1. Treatment of the NCI-H929 cells with ET-1 increased proliferation, while co-incubation of these cells with ET-1 and BTZ decreased BTZ efficacy with concomitant upregulation of 20S proteasomal activity. Si-RNA silencing or chemical blockade of ETBR abrogated the protective effects of ET-1. Finally, data suggest that the predominant signaling pathway involved in ET-1/ETBR-induced BTZ resistance in MM cells may be the MAPK pathway. CONCLUSION Our data suggest a possible role of the ET-1/ETBR axis in regulating the sensitivity of MM cells to BTZ. Thus, combining bortezomib with strategies to target the ET-1 axis could prove to be a novel promising therapeutic approach in MM.
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He S, Park YH, Yorio T, Krishnamoorthy RR. Endothelin-Mediated Changes in Gene Expression in Isolated Purified Rat Retinal Ganglion Cells. Invest Ophthalmol Vis Sci 2015; 56:6144-61. [PMID: 26397462 DOI: 10.1167/iovs.15-16569] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
PURPOSE A growing body of evidence suggests that the vasoactive peptides endothelins (ETs) and their receptors (primarily the ETB receptor) are contributors to neurodegeneration in glaucoma. However, actions of ETs in retinal ganglion cells (RGCs) are not fully understood. The purpose of this study was to determine the effects of ETs on gene expression in primary RGCs. METHODS Primary RGCs isolated from rat pups were treated with 100 nM of ET-1, ET-2, or ET-3 for 24 hours. Total RNA was extracted followed by cDNA synthesis. Changes in gene expression in RGCs were detected using Affymetrix Rat Genome 230 2.0 microarray and categorized by DAVID analysis. Real-time PCR was used to validate gene expression, and immunocytochemistry and immunoblotting to confirm the protein expression of regulated genes. RESULTS There was more than 2-fold upregulation of 328, 378, or 372 genes, and downregulation of 48, 33, or 28 genes with ET-1, ET-2, or ET-3 treatment, respectively, compared to untreated controls. The Bcl-2 family, S100 family, matrix metalloproteinases, c-Jun, and ET receptors were the major genes or proteins that were regulated by endothelin treatment. Immunocytochemical staining revealed a significant increase in ETA receptor, ETB receptor, growth associated protein 43 (GAP-43), phosphorylated c-Jun, c-Jun, and Bax with ET-1 treatment. Protein levels of GAP-43 and c-Jun were confirmed by immunoblotting. CONCLUSIONS Expression of key proteins having regulatory roles in apoptosis, calcium homeostasis, cell signaling, and matrix remodeling were altered by treatment with endothelins. The elucidation of molecular mechanisms underlying endothelins' actions in RGCs will help understand endothelin-mediated neurodegenerative changes during ocular hypertension.
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Affiliation(s)
- Shaoqing He
- Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, Texas, United States 2North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Yong H Park
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States 3Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Thomas Yorio
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States 3Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Raghu R Krishnamoorthy
- Department of Cell Biology and Immunology, University of North Texas Health Science Center, Fort Worth, Texas, United States 2North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
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Michel K, Büther K, Law MP, Wagner S, Schober O, Hermann S, Schäfers M, Riemann B, Höltke C, Kopka K. Development and Evaluation of Endothelin-A Receptor (Radio)Ligands for Positron Emission Tomography. J Med Chem 2011; 54:939-48. [DOI: 10.1021/jm101110w] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kristin Michel
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Katrin Büther
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Marilyn P. Law
- European Institute for Molecular Imaging, University of Münster, Mendelstrasse 11, D-48149 Münster, Germany
- Interdisciplinary Centre of Clinical Research (IZKF), Münster, Germany
| | - Stefan Wagner
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Otmar Schober
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Sven Hermann
- European Institute for Molecular Imaging, University of Münster, Mendelstrasse 11, D-48149 Münster, Germany
| | - Michael Schäfers
- European Institute for Molecular Imaging, University of Münster, Mendelstrasse 11, D-48149 Münster, Germany
- Interdisciplinary Centre of Clinical Research (IZKF), Münster, Germany
| | - Burkhard Riemann
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Carsten Höltke
- Department of Clinical Radiology, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
| | - Klaus Kopka
- Department of Nuclear Medicine, University Hospital Münster, Albert-Schweitzer-Strasse 33, D-48149 Münster, Germany
- Interdisciplinary Centre of Clinical Research (IZKF), Münster, Germany
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Tomkinson HK, Kemp JV, Wollseifen T, Morris T, Oliver SD. An open-label, randomized, single-center, two-period, phase I, crossover study of the effect of zibotentan (ZD4054) on the pharmacokinetics of midazolam in healthy male volunteers. Clin Ther 2010; 32:1372-86. [DOI: 10.1016/j.clinthera.2010.07.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2010] [Indexed: 11/16/2022]
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Höltke C, Law MP, Wagner S, Kopka K, Faust A, Breyholz HJ, Schober O, Bremer C, Riemann B, Schäfers M. PET-compatible endothelin receptor radioligands: Synthesis and first in vitro and in vivo studies. Bioorg Med Chem 2009; 17:7197-208. [DOI: 10.1016/j.bmc.2009.08.058] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2009] [Revised: 08/12/2009] [Accepted: 08/28/2009] [Indexed: 11/29/2022]
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Ghoul A, Serova M, Astorgues-Xerri L, Bieche I, Bousquet G, Varna M, Vidaud M, Phillips E, Weill S, Benhadji KA, Lokiec F, Cvitkovic E, Faivre S, Raymond E. Epithelial-to-mesenchymal transition and resistance to ingenol 3-angelate, a novel protein kinase C modulator, in colon cancer cells. Cancer Res 2009; 69:4260-9. [PMID: 19417139 DOI: 10.1158/0008-5472.can-08-2837] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Acquired resistance to protein kinase C (PKC) modulators may explain the failure of clinical trials in patients with cancer. Herein, we established a human colon cancer cell line resistant to PEP005, a drug that inhibits PKCalpha and activates PKCdelta. Colo205-R cells, selected by stepwise exposure to PEP005, were >300-fold more resistant to PEP005 than parental Colo205-S cells and were cross-resistant to phorbol 12-myristate 13-acetate, bryostatin, bistratene A, and staurosporine. No PKCalpha or PKCdelta mutation was detected in Colo205-S and Colo205-R cells. Changes in Colo205-R cells were reminiscent of the epithelial-to-mesenchymal transition (EMT) phenotype. Accordingly, Colo205-R cells were more invasive than Colo205-S in Matrigel assays and in mouse xenografts. We also found an increased mRNA expression of several EMT genes, such as those encoding for transforming growth factor-beta and vimentin, along with a decreased mRNA expression of genes involved in epithelial differentiation, such as CDH1 (E-cadherin), CLDN4 (claudin 4), S100A4, and MUC1, in Colo205-R compared with Colo205-S cells in vitro and in vivo. Interestingly, high expression of ET-1 was shown in Colo205-R cells and correlated with low sensitivity to PEP005 and staurosporine in a panel of 10 human cancer cell lines. Inhibition of the ET-1 receptor ETR-A with bosentan restored the antiproliferative effects of PEP005 in Colo205-R cells and decreased the invasive properties of this cell line. Exogenous exposure to ET-1 and silencing ET-1 expression using small interfering RNA modulated cell signaling in Colo205-S and Colo205-R. In summary, acquired resistance to PEP005 was associated with expression of EMT markers and activates the ET-1/ETR-A cell signaling.
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Affiliation(s)
- Aïda Ghoul
- Institut National de la Sante et de la Recherche Medicale U728, RayLab, and Department of Medical Oncology, Beaujon and Saint-Louis University Hospital (AP-HP-Paris 7 Diderot), Clichy, France
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Tang L, Su M, Zhang Y, Ip W, Martinka M, Huang C, Zhou Y. Endothelin-3 is produced by metastatic melanoma cells and promotes melanoma cell survival. J Cutan Med Surg 2008; 12:64-70. [PMID: 18346402 DOI: 10.2310/7750.2008.06164] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Endothelin-3 (ET-3) is an essential paracrine factor for the proliferation, migration, and survival of embryonic melanocytes during fetal development. Its expression is tightly regulated, being completely turned off in adult skin. OBJECTIVE In this study, results are presented that demonstrate abnormal expression of ET-3 by metastatic melanoma cells in both tissue biopsies and cell culture. Further, in vitro experiments showed that metastatic melanoma cells have the capacity to respond to ET-3 stimulation by increasing survival. CONCLUSION Therefore, an abnormal autocrine stimulation pathway involving ET-3 is present in metastatic melanoma cells. Blocking this signal transduction pathway may prove useful for the treatment of metastatic melanoma.
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Affiliation(s)
- Liren Tang
- Department of Dermatology and Skin Science, University of British Columbia, Vancouver, BC
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Rajeshkumar NV, Matwyshyn G, Gulati A. IRL-1620, a tumor selective vasodilator, augments the uptake and efficacy of chemotherapeutic agents in prostate tumor rats. Prostate 2007; 67:701-13. [PMID: 17342753 DOI: 10.1002/pros.20556] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND IRL-1620, a potent endothelin B receptor agonist, enhanced the efficacy of paclitaxel in a breast tumor model, but its effect in prostate cancer is not known. The present study was conducted to evaluate the effect of IRL-1620 on tumor perfusion, uptake of [(14)C]-doxorubicin in the tumor and efficacy of doxorubicin (DOX), and 5-flurouracil (5-FU) in a rat prostate tumor model. METHODS JHU-4 (Mat-Lu) cells inoculated prostate tumor model in Copenhagen rats was used for the study. RESULTS Administration of IRL-1620 (3 nmol/kg, i.v) significantly increased (102.8%) prostate tumor perfusion and tumor uptake of [(14)C]-doxorubicin (115%) compared to vehicle treated rats. Results of the efficacy study demonstrate that IRL-1620 administration 15 min prior to DOX (5 mg/kg) or 5-FU (50 mg/kg) on every third day for a total of four doses significantly reduced tumor volume compared to vehicle treated rats. CONCLUSIONS IRL-1620 significantly enhanced the uptake and efficacy of anticancer agents in prostate cancer.
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Affiliation(s)
- N V Rajeshkumar
- Department of Biopharmaceutical Sciences, University of Illinois, Chicago, Illinois, USA
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Doppalapudi VR, Tryder N, Li L, Aja T, Griffith D, Liao FF, Roxas G, Ramprasad MP, Bradshaw C, Barbas CF. Chemically programmed antibodies: endothelin receptor targeting CovX-Bodies. Bioorg Med Chem Lett 2006; 17:501-6. [PMID: 17055724 DOI: 10.1016/j.bmcl.2006.10.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Accepted: 10/05/2006] [Indexed: 11/27/2022]
Abstract
Aryl sulfonamide-based endothelin antagonists were synthesized and covalently linked to the reactive lysine of the m38C2 antibody to create a series of CovX-Bodies. These chemically programmed antibodies behaved as potent endothelin receptor antagonists in vitro and had antitumor efficacy in a prostate cancer xenograft model which, on a molar basis, far exceeded the activity of the parent small molecule.
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Felx M, Guyot MC, Isler M, Turcotte RE, Doyon J, Khatib AM, Leclerc S, Moreau A, Moldovan F. Endothelin-1 (ET-1) promotes MMP-2 and MMP-9 induction involving the transcription factor NF-kappaB in human osteosarcoma. Clin Sci (Lond) 2006; 110:645-54. [PMID: 16417466 DOI: 10.1042/cs20050286] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In the present study, we have investigated the effect of (i) ET-1 (endothelin-1) and its precursor, big ET-1, on MMP (matrix metalloproteinase)-2 and MMP-9 synthesis and activity in osteosarcoma tissue, and (ii) ET-1 receptor antagonists on cell invasion. Using Western blotting, zymography, RT-PCR (reverse transcription-PCR), immunohistochemistry, immunofluorescence and Northern blotting, we have shown that ET-1 and ET-1 receptors (ET(A) and ET(B)) were expressed in these cells. Additionally, we have demonstrated that ET-1 markedly induced the synthesis and activity of MMP-2, which was significantly increased when compared with MMP-9. Furthermore, inhibition of NF-kappaB (nuclear factor kappaB) activation blocked MMP-2 production and activity, indicating the involvement of NF-kappaB, a ubiquitous transcription factor playing a central role in the differentiation, proliferation and malignant transformation. Since ET-1 acts as an autocrine mediator through gelatinase induction and because inhibition of ET(A) receptor is beneficial for reducing both basal and ET-1-induced osteosarcoma cell invasion, targeting this receptor could be an attractive therapeutic alternative for the successful treatment of osteosarcoma.
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Affiliation(s)
- Mélanie Felx
- Research Centre of the CHU Sainte-Justine Hospital, Montreal, QC, Canada
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Hearnes JM, Mays DJ, Schavolt KL, Tang L, Jiang X, Pietenpol JA. Chromatin immunoprecipitation-based screen to identify functional genomic binding sites for sequence-specific transactivators. Mol Cell Biol 2005; 25:10148-58. [PMID: 16260627 PMCID: PMC1280257 DOI: 10.1128/mcb.25.22.10148-10158.2005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Revised: 06/06/2005] [Accepted: 08/28/2005] [Indexed: 02/05/2023] Open
Abstract
In various human diseases, altered gene expression patterns are often the result of deregulated gene-specific transcription factor activity. To further understand disease on a molecular basis, the comprehensive analysis of transcription factor signaling networks is required. We developed an experimental approach, combining chromatin immunoprecipitation (ChIP) with a yeast-based assay, to screen the genome for transcription factor binding sites that link to transcriptionally regulated target genes. We used the tumor suppressor p53 to demonstrate the effectiveness of the method. Using primary and immortalized, nontransformed cultures of human mammary epithelial cells, we isolated over 100 genomic DNA fragments that contain novel p53 binding sites. This approach led to the identification and validation of novel p53 target genes involved in diverse signaling pathways, including growth factor signaling, protein kinase/phosphatase signaling, and RNA binding. Our results yield a more complete understanding of p53-regulated signaling pathways, and this approach could be applied to any number of transcription factors to further elucidate complex transcriptional networks.
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Affiliation(s)
- Jamie M Hearnes
- Department of Biochemistry, Center for Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Nashville, TN 37232-6838, USA
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Rajeshkumar NV, Rai A, Gulati A. Endothelin B receptor agonist, IRL 1620, enhances the anti-tumor efficacy of paclitaxel in breast tumor rats. Breast Cancer Res Treat 2005; 94:237-47. [PMID: 16244791 DOI: 10.1007/s10549-005-9000-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Pharmacological agents that increase tumor blood flow could be utilized to promote the delivery of anti-cancer drugs. We have demonstrated that administration of endothelin-1 (ET-1) to breast tumor bearing rats transiently increased tumor blood flow by stimulating endothelin B (ET(B)) receptors. The present study evaluated the effect of ET(B) receptor agonist, IRL 1620, on breast tumor perfusion, concentration of [3H]paclitaxel in tumor and tissues, and efficacy of paclitaxel in N-methyl nitrosourea induced breast tumor bearing rats. Administration of IRL 1620 (3 and 9 nmol/kg) significantly increased (203 and 140%, respectively) breast tumor perfusion. BQ 788, an ET(B) receptor antagonist, pretreatment completely abolished IRL 1620 induced increase in tumor perfusion. Tumor [3H]paclitaxel concentration was increased by 308% when [3H]paclitaxel was administered 15 min after IRL 1620 (3 nmol/kg) compared to vehicle treated rats. However, IRL 1620 did not increase [3H]paclitaxel concentrations in other organs. Efficacy study showed that paclitaxel (5 mg/kg) administration on every third day for a total of five doses produced 60.0, 4.5 and 0% reduction in tumor volume, tumor progression and complete tumor remission, respectively, compared to saline treated rats. However, paclitaxel (5 mg/kg) when administered 15 min after IRL 1620 (3 nmol/kg) produced 268.9, 210.3 and 20% reduction in tumor volume, tumor progression and complete remission of tumors, respectively, compared to saline treated rats. In conclusion, IRL 1620 significantly enhanced delivery and effectiveness of paclitaxel in an animal model of breast cancer.
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Affiliation(s)
- N V Rajeshkumar
- Department of Biopharmaceutical Sciences, University of Illinois at Chicago, 833 South Wood Street, Chicago, IL 60612, USA
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Henshaw DL, Reiter RJ. Do magnetic fields cause increased risk of childhood leukemia via melatonin disruption? Bioelectromagnetics 2005; Suppl 7:S86-97. [PMID: 16059923 DOI: 10.1002/bem.20135] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Epidemiological studies have reported associations between exposure to power frequency magnetic fields and increased risk of certain cancer and noncancer illnesses. For childhood leukemia, a doubling of risk has been associated with exposures above 0.3/0.4 microT. Here, we propose that the melatonin hypothesis, in which power frequency magnetic fields suppress the nocturnal production of melatonin in the pineal gland, accounts for the observed increased risk of childhood leukemia. Such melatonin disruption has been shown in animals, especially with exposure to electric and/or rapid on/off magnetic fields. Equivocal evidence has been obtained from controlled laboratory magnetic field exposures of volunteers, although the exposure conditions are generally atypical of neighborhood exposures. In contrast, support for the hypothesis is found in the body of studies showing magnetic field disruption of melatonin in human populations chronically exposed to both electric and magnetic fields associated with electricity distribution. Further support comes from the observation that melatonin is highly protective of oxidative damage to the human haemopoietic system. Aspects of the hypothesis are amenable to further investigation.
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Affiliation(s)
- Denis L Henshaw
- H.H. Wills Physics Laboratory, University of Bristol, Bristol, United Kingdom.
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