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Qian K, Mao B, Zhang W, Chen H. MicroRNA-561 inhibits gastric cancercell proliferation and invasion by downregulating c-Myc expression. Am J Transl Res 2016; 8:3802-3811. [PMID: 27725860 PMCID: PMC5040678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 08/01/2015] [Indexed: 06/06/2023]
Abstract
Gastric cancer (GC) causes nearly one million deaths worldwide each year. However, the molecular pathway of GC development remains unclear. Increasing evidences have shown that microRNAs (miRNAs) are highly associated with tumor development. However, relative little is known about the potential role of miRNAs in gastric cancer development. In the present study, we showed that miR-561 was down-regulated frequently in human GCs cell lines and tissues, and its expression was associated with tumor-node-metastasis (pTNM) stage. Enforced expression of miR-561 in GC cells inhibited cell proliferation and invasion in vitro. In contrast, knockdown of miR-561 had the opposite effect on cell proliferation and invasion. Moreover, c-Myc was identified as a potential miR-561 target. Further studies confirmed that miR-561 suppressed the expression of c-Myc by directly binding to its 3'-untranslated region. Restoration of c-Myc in miR-561-overexpressed GC cells reversed the suppressive effects of miR-561 and c-Myc was inversely correlated with miR-561 expression in GC tissues. These results demonstrate that miR-561 acts as a novel tumor suppressor in GC by targeting c-Myc gene and inhibiting GC cells proliferation and invasion. These findings contribute to current understanding of the functions of miR-561 in GC.
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Affiliation(s)
- Kun Qian
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016, China
| | - Binglang Mao
- The Medical Examination Center, The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016, China
| | - Wei Zhang
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016, China
| | - Huanwen Chen
- Department of Cardiothoracic Surgery, The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016, China
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2
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Wang F, Remke M, Bhat K, Wong ET, Zhou S, Ramaswamy V, Dubuc A, Fonkem E, Salem S, Zhang H, Hsieh TC, O'Rourke ST, Wu L, Li DW, Hawkins C, Kohane IS, Wu JM, Wu M, Taylor MD, Wu E. A microRNA-1280/JAG2 network comprises a novel biological target in high-risk medulloblastoma. Oncotarget 2015; 6:2709-24. [PMID: 25576913 PMCID: PMC4413612 DOI: 10.18632/oncotarget.2779] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 11/19/2014] [Indexed: 01/23/2023] Open
Abstract
Over-expression of PDGF receptors (PDGFRs) has been previously implicated in high-risk medulloblastoma (MB) pathogenesis. However, the exact biological functions of PDGFRα and PDGFRβ signaling in MB biology remain poorly understood. Here, we report the subgroup specific expression of PDGFRα and PDGFRβ and their associated biological pathways in MB tumors. c-MYC, a downstream target of PDGFRβ but not PDGFRα, is involved in PDGFRβ signaling associated with cell proliferation, cell death, and invasion. Concurrent inhibition of PDGFRβ and c-MYC blocks MB cell proliferation and migration synergistically. Integrated analysis of miRNA and miRNA targets regulated by both PDGFRβ and c-MYC reveals that increased expression of JAG2, a target of miR-1280, is associated with high metastatic dissemination at diagnosis and a poor outcome in MB patients. Our study may resolve the controversy on the role of PDGFRs in MB and unveils JAG2 as a key downstream effector of a PDGFRβ-driven signaling cascade and a potential therapeutic target.
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Affiliation(s)
- Fengfei Wang
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND 58105, USA
| | - Marc Remke
- Arthur and Sonia Labatt Brain Tumor Research Centre, Program in Developmental and Stem Cell Biology, Hospital for Sick Children, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Kruttika Bhat
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND 58105, USA
| | - Eric T Wong
- Brain Tumor Center & Neuro-Oncology Unit, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - Shuang Zhou
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND 58105, USA
| | - Vijay Ramaswamy
- Arthur and Sonia Labatt Brain Tumor Research Centre, Program in Developmental and Stem Cell Biology, Hospital for Sick Children, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Adrian Dubuc
- Arthur and Sonia Labatt Brain Tumor Research Centre, Program in Developmental and Stem Cell Biology, Hospital for Sick Children, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Ekokobe Fonkem
- Scott & White Neuroscience Institute, Texas A & M Health Science Center, Temple, TX 76508, USA
| | - Saeed Salem
- Department of Computer Sciences, North Dakota State University, Fargo, ND 58105, USA
| | - Hongbing Zhang
- Department of Physiology, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100073, China
| | - Tze-Chen Hsieh
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA
| | - Stephen T O'Rourke
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND 58105, USA
| | - Lizi Wu
- Department of Molecular Genetics and Microbiology, Shands Cancer Center, University of Florida, Gainesville, FL 32610, USA
| | - David W Li
- Department of Ophthalmology & Visual Sciences, College of Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Cynthia Hawkins
- Division of Pathology, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Isaac S Kohane
- Informatics Program, Children's Hospital Boston, Harvard Medical School, Boston 02115, MA, USA
| | - Joseph M Wu
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY 10595, USA
| | - Min Wu
- Department of Biochemistry and Molecular Biology, University of North Dakota, Grand Forks, ND 58202, USA
| | - Michael D Taylor
- Arthur and Sonia Labatt Brain Tumor Research Centre, Program in Developmental and Stem Cell Biology, Hospital for Sick Children, University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Erxi Wu
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, ND 58105, USA
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Windischhofer W, Huber E, Rossmann C, Semlitsch M, Kitz K, Rauh A, Devaney T, Leis HJ, Malle E. LPA-induced suppression of periostin in human osteosarcoma cells is mediated by the LPA(1)/Egr-1 axis. Biochimie 2012; 94:1997-2005. [PMID: 22659570 PMCID: PMC3407874 DOI: 10.1016/j.biochi.2012.05.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 05/07/2012] [Indexed: 01/30/2023]
Abstract
Lysophosphatidic acid (LPA), a naturally occurring bioactive phospholipid, mediates a multitude of (patho)physiological events including activation of mitogen-activated protein kinases (MAPKs). As LPA may induce cellular reponses in human osteosarcoma, the present study aimed at investigating expression of various LPA receptors, LPA-mediated activation of MAPK via G-protein coupling, and expression of early response genes in a cellular model for human osteosarcoma. We show that MG-63 cells express three members of the endothelial differentiation gene (Edg) family of G-protein coupled receptor transcripts (LPA(1-3)) but only two (LPA(4/5)) out of three members of the non-Edg family LPA receptor transcripts. Stimulation of MG-63 cells with LPA or synthetic LPA receptor agonists resulted in p42/44 MAPK phosphorylation via LPA(1)-LPA(3) receptors. Using pharmacological inhibitors, we show that LPA-mediated phosphorylation of p42/44 MAPK by LPA receptor engagement is transmitted by G(αi)-dependent pathways through the Src family of tyrosine kinases. As a consequence, a rapid and transient upregulation of the zinc finger transcription factor early growth response-1 (Egr-1) was observed. Egr-1 expression was strictly mediated via G(αi)/Src/p42/44 MAPK pathway; no involvement of the G(αq/11)/PLC/PKC or the PLD/PI3 kinase/Akt pathways was found. LPA-induced expression of functional Egr-1 in MG-63 cells could be confirmed by electrophoretic mobility shift assay. LPA-induced Egr-1 upregulation was accompanied by a time-dependent decrease of periostin (previously called osteoblast-specific factor 2), a cell adhesion protein for pre-osteoblasts. Silencing of LPA(1) and/or Egr-1 in MG-63 cells reversed LPA-mediated suppression of periostin. We here demonstrate a crosslink between Egr-1 and periostin in cancer cells, in particular in human osteosarcoma.
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Affiliation(s)
- Werner Windischhofer
- Medical University of Graz, University Clinic of Pediatrics and Adolescent Medicine, Research Unit of Osteological Research and Analytical Mass Spectrometry, Auenbruggerplatz 30, A-8036 Graz, Austria.
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Small GW, Chou TY, Dang CV, Orlowski RZ. Evidence for involvement of calpain in c-Myc proteolysis in vivo. Arch Biochem Biophys 2002; 400:151-61. [PMID: 12054425 DOI: 10.1016/s0003-9861(02)00005-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Precise control of the level of c-Myc protein is important to normal cellular homeostasis, and this is accomplished in part by degradation through the ubiquitin-proteasome pathway. The calpains are a family of calcium-dependent proteases that play important roles in proteolysis of some proteins, and their possible participation in degradation of intracellular c-Myc was therefore investigated. Activation of calpain with the cell-permeable calcium ionophore A23187 in Rat1a-myc or ts85 cells in culture induced rapid cleavage of c-Myc. This degradation was both calpain- and calcium-dependent since it was inhibited by preincubation with either the calpain-inhibitory peptide calpeptin or the calcium-chelating agent EGTA. A23187-induced c-Myc cleavage occurred in a time-dependent manner comparable to that of FAK, a known calpain substrate, and while calpeptin was able to significantly protect c-Myc from degradation, inhibitors of the proteasome or caspase proteases could not. Exposure of Rat1a-myc or ts85 cells in culture to calpeptin, or to the thiol-protease inhibitor E64d, resulted in the accumulation of c-Myc protein without an impact on ubiquitin-protein conjugates. Using an in vitro assay, calpain-mediated degradation occurred rapidly with wild-type c-Myc as the substrate, but was significantly prolonged in some c-Myc mutants with increased transforming activity derived from lymphoma patients. Those mutants with a prolonged half-life in vitro were also more resistant to A23187-induced cleavage in intact cells. These studies support a role for calpain in the control of c-Myc levels in vivo, and suggest that mutations impacting on sensitivity to calpain may contribute to c-Myc-mediated tumorigenesis.
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Affiliation(s)
- George W Small
- The Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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Abstract
In dog thyroid epithelial cells in primary culture, thyrotropin (TSH), acting through cAMP, induces proliferation and differentiation expression, whereas epidermal growth factor (EGF) and phorbol esters induce proliferation and dedifferentiation. In these cells, we have detailed the regulation by cAMP of the c-myc protooncogene mRNA and protein. The cAMP signaling pathway induces a biphasic increase of c-myc mRNA and protein. c-Myc protein accumulation follows the abundance and kinetics of its mRNA expression. Using in vitro elongation of nascent transcripts to measure transcription and actinomycin D (AcD) chase experiments to study mRNA stability, we have shown that in the first phase cAMP releases a transcriptional elongation block. No modification of transcriptional initiation was observed. After 30 min of treatment with TSH, c-myc mRNA was also stabilized. During the second phase, cAMP stabilization of the mRNA disappears and transcription is again shut off. Thus, in a tissue in which it stimulates proliferation and specific gene expression, cAMP regulates biphasically c-myc expression by mechanisms operating at the transcriptional and posttranscriptional levels.
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Affiliation(s)
- I Pirson
- Institute of Interdisciplinary Research, School of Medicine, Free University of Brussels, Belgium
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Srivastava VK, Schroeder MD, Miller SD, Busbee DL. Differential expression of DNA polymerase alpha in normal and transformed human fibroblasts. Mutat Res 1996; 316:267-75. [PMID: 8649460 DOI: 10.1016/s0921-8734(96)90009-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The expression of DNA polymerase alpha (pol alpha) was studied in human fibroblast lines W138 (fetal lung) and GM3529 (skin, established from a 66 yr old donor), and their Simian virus 40 (SV40) large tumor antigen (TAg)-transformed corollaries, 2RA and 2-1 respectively. Both SV40-transformed and pSV3.neo (SV40-derived plasmid)-transformed cells express TAg, a virally encoded protein not expressed by the normal parent cell lines. Northern blot hybridization studies showed increased recovery of pol alpha mRNA from transformed cells compared with normal cells. This increase was correlated with increased pol alpha mRNA transcription as determined by nuclear run-on assays. Northern blot analyses also showed an increase in the instability of translationally active pol alpha mRNA in transformed cells. The results suggest that TAg, in addition to its dsDNA binding, pol alpha binding, retinoblastoma protein binding and helicase activities, may be involved either directly or indirectly in regulation of the steady state mRNA levels of pol alpha at the transcriptional level in both fetal and aged donor-derived transformed fibroblasts.
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Affiliation(s)
- V K Srivastava
- Department of Anatomy and Public Health, College of Veterinary Medicine, Texas A & M University, College Station 77843, USA
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Zhang BT, Hikawa N, Horie H, Takenaka T. Mitogen induced proliferation of isolated adult mouse Schwann cells. J Neurosci Res 1995; 41:648-54. [PMID: 7563245 DOI: 10.1002/jnr.490410511] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The proliferation of neonatal Schwann cells (SCs) in response to mitogenic agents has been well analyzed in vitro, but a limited range of mitogens have been defined. We investigated whether three identified neonatal SC mitogens [glial growth factor (GGF), platelet-derived growth factor BB (PDGF-BB), and basic fibroblast growth factor (bFGF)] are required to stimulate mitosis of adult SCs. Adult SCs were isolated from mouse sciatic nerves by mechanical and chemical dissociation, following three experimental steps: 1) culturing the dissociated cells for 24 hr in 10% FCS-F12 medium, 2) culturing these cells in serum-free medium for the next 48 hr, and 3) purifying adult SCs by differential adhesion. We describe a new method for preparation of SCs from peripheral nerves of adult mouse that provides 99.5% pure SCs populations at cell yields of greater than 3 x 10(3) cells/mg of starting nerve wet weight within 5 culture days. Although mitosis of SCs in culture in response to mitogens requires the presence of serum, the complex nature of serum renders difficult a complete analysis of mitogens required for SCs DNA synthesis, so we examined the proliferating response of adult SCs to GGF, PDGF-BB, and bFGF in serum-free medium. GGF alone had mitogenicity for adult SCs in a dose-dependent manner, and synergistic activation coupling with forskolin was not observed. Neither PDGF-BB nor bFGF was mitogenic for adult SCs when used alone or with forskolin.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- B T Zhang
- Department of Physiology, School of Medicine, Yokohama City University, Japan
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