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Jain CV, Jessmon P, Kilburn BA, Jodar M, Sendler E, Krawetz SA, Armant DR. Regulation of HBEGF by Micro-RNA for Survival of Developing Human Trophoblast Cells. PLoS One 2016; 11:e0163913. [PMID: 27701455 PMCID: PMC5049799 DOI: 10.1371/journal.pone.0163913] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/17/2016] [Indexed: 11/30/2022] Open
Abstract
Introduction The growth factor HBEGF is upregulated post-transcriptionally in the low O2 environment of the human placenta during the first 10 weeks of pregnancy. We have examined the possible roles of HBEGF turnover and micro-RNA (miRNA) in its regulation by O2 in human first trimester trophoblast. Methods HTR-8/SVneo trophoblast cells were cultured at 2% or 20% O2. The cells were transfected with a dual luciferase reporter construct (psiCHECK-2) containing no insert (control), the HBEGF 3’ untranslated region (3’UTR), or sub-regions of the 3’UTR, as well as with siRNA for DGCR8. RNA was extracted from trophoblast cells cultured at 2% O2 for 0–4 h for next-generation sequencing. HBEGF was quantified by ELISA. HBEGF, DGCR8, and β–actin were examined by western blotting. Results Protein turnover studies, using 10 μg/ml cyclohexamide, 1 μg/ml lactocystin, or 100 μg/ml MG132, demonstrated faster HBEGF degradation at 20% O2 than 2% O2, mediated by the proteasome. However, proteasome inhibition failed to initiate HBEGF accumulation at 20% O2. Reporter assays, comparing to empty vector, demonstrated that the intact HBEGF 3’ UTR inhibited expression (0.26), while fragments containing only its flanking regions increased reporter activity (3.15; 3.43). No differential expression of miRNAs was found in trophoblast cells cultured at 2% and 20% O2. Nevertheless, HBEGF upregulation at 2% O2 was blocked when the miRNA-processing protein DGCR8 was silenced, suggesting a role for miRNA. Conclusion Our findings suggest involvement of flanking regions of the 3’UTR in activating HBEGF protein synthesis in response to 2% O2, possibly through a miRNA-mediated mechanism.
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Affiliation(s)
- Chandni V. Jain
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Philip Jessmon
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Brian A. Kilburn
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Meritxell Jodar
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- Department of Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Edward Sendler
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- Department of Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Stephen A. Krawetz
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- Department of Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - D. Randall Armant
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, DHHS, Bethesda, MD, United States of America
- * E-mail:
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Nakayama H, Fukuda S, Matsushita N, Nishida-Fukuda H, Inoue H, Shirakata Y, Hashimoto K, Higashiyama S. Human antigen R-mediated mRNA stabilization is required for ultraviolet B-induced autoinduction of amphiregulin in keratinocytes. J Biol Chem 2013; 288:10338-48. [PMID: 23430747 DOI: 10.1074/jbc.m112.417527] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
All members of the EGF family are produced as transmembrane precursors that are proteolytically processed into soluble forms by disintegrin and metalloproteinases (ADAMs) for autocrine/paracrine pathways. In turn, the ligand-activated EGF receptor (EGFR) induces the expression of EGF family members, so-called "autoinduction." However, it is not well understood how this autoinduction occurs. In this study, we investigated the molecular mechanism of the autoinduction of amphiregulin (AREG), a member of the EGF family. We found that ultraviolet B (UVB) exposure increased the AREG mRNA level by stabilization of its mRNA in a human immortalized keratinocyte cell line, HaCaT. The 3' UTR of AREG mRNA was responsible for binding to an mRNA-binding protein, human antigen R (HuR), and the interaction between AREG mRNA and HuR was enhanced by UVB. Inducible knockdown of HuR expression significantly decreased AREG mRNA stability. Interestingly, treatment of HaCaT cells with an EGFR inhibitor, an EGFR neutralizing antibody, or an ADAM inhibitor destabilized AREG mRNA. In the case of ADAM inhibition, administration of soluble AREG restored the mRNA level, indicating that the stabilization occurs in a shedding-dependent manner of EGFR ligands. The HuR dependence of AREG mRNA and protein expression was also confirmed in human primary keratinocytes. Taken together, we propose a novel mechanism by which HuR regulates the stability of AREG mRNA in keratinocytes after UVB exposure and suggest that targeting of HuR functions might be crucial for understanding skin cancers caused by aberrant EGF family member-EGFR signaling.
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Affiliation(s)
- Hironao Nakayama
- Department of Biochemistry and Molecular Genetics, Ehime University, Shitsukawa, Toon, Ehime 791-0295, Japan
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Laloo B, Simon D, Veillat V, Lauzel D, Guyonnet-Duperat V, Moreau-Gaudry F, Sagliocco F, Grosset C. Analysis of post-transcriptional regulations by a functional, integrated, and quantitative method. Mol Cell Proteomics 2010; 8:1777-88. [PMID: 19411282 DOI: 10.1074/mcp.m800503-mcp200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the past 10 years, transcriptome and proteome analyses have provided valuable data on global gene expression and cell functional networks. However, when integrated,these analyses revealed partial correlations between mRNA expression levels and protein abundance thus suggesting that post-transcriptional regulations may be in part responsible for this discrepancy. In the present work, we report the development of a functional, integrated, and quantitative method to measure post-transcriptional regulations that we named FunREG. This method enables (i) quantitative measure of post-transcriptional regulations mediated by selected 3-untranslated regions and exogenous small interfering-RNA or micro-RNAs and (ii) comparison of these regulatory processes in physiologically relevant systems (e.g. cancer versus primary untransformed cells). We applied FunREG to the study of liver cancer, and we demonstrate for the first time the differential regulatory mechanisms controlling gene expression at a post-transcriptional level in normal and tumoral hepatic cells. As an example, translation efficiency mediated by heparin-binding epidermal growth factor 3-untranslated region was increased 3-fold in liver cancer cells compared with normal hepatocytes, whereas stability of an mRNA containing a portion of Cyclin D1 3-untranslated region was increased more than 2-fold in HepG2 cells compared with normal hepatocytes. Consequently we believe that the method presented herein may become an important tool in fundamental and medical research. This approach is convenient and easy to perform, accessible to any investigator, and should be adaptable to a large number of cell type, functional and chemical screens, as well as genome scale analyses. Finally FunREG may represent a helpful tool to reconcile transcriptome and proteome data.
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Affiliation(s)
- Benoît Laloo
- INSERM, U889, Groupe de Recherche pour l'Etude du Foie (GREF), Bordeaux, F-33076 France
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Huang WC, Hung MC. Induction of Akt activity by chemotherapy confers acquired resistance. J Formos Med Assoc 2009; 108:180-94. [PMID: 19293033 DOI: 10.1016/s0929-6646(09)60051-6] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Resistance to chemotherapy is a major cause of treatment failure in human cancer. Accumulating evidence has indicated that the acquisition of resistance to chemotherapeutic drugs involves the activation of the PI3K/Akt pathway. Modulating Akt activity in response to chemotherapy has been observed often in chemoresistant cancers. The potential molecular mechanisms by which chemotherapeutic agents activate the PI3K/Akt pathway are emerging. Activation of this pathway evades the cytotoxic effects of chemotherapeutic agents via regulation of essential cellular functions such as protein synthesis, antiapoptosis, survival and proliferation in cancer. How chemotherapeutic agents induce Akt activation and how activated Akt confers chemoresistance through regulation of signaling networks are discussed in this review. Combining PI3K/Akt inhibitors with standard chemotherapy has been successful in increasing the efficacy of chemotherapeutic agents both in vivo and in vitro. Several small molecules have been developed to specifically target PI3K/Akt and other components of this pathway, which in combination with chemotherapy may be a valid approach to overcome therapeutic resistance. We propose several feedback and feedforward regulatory mechanisms of signaling networks for maintenance of the Akt activity for cell survival. These regulatory mechanisms may limit the efficacy of PI3K/Akt-targeted therapy; therefore, disruption of these mechanisms may be an effective strategy for development of novel anti-cancer therapies.
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Affiliation(s)
- Wei-Chien Huang
- Center for Molecular Medicine and Graduate Institute of Cancer Biology, China Medical University and Hospital, and Department of Biotechnology, Asia University, Taichung, Taiwan.
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Edwards JP, Zhang X, Mosser DM. The expression of heparin-binding epidermal growth factor-like growth factor by regulatory macrophages. THE JOURNAL OF IMMUNOLOGY 2009; 182:1929-39. [PMID: 19201846 DOI: 10.4049/jimmunol.0802703] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We previously described a population of regulatory macrophages that produced high levels of IL-10 and low levels of IL-12/23. We now describe and characterize the expression of heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF) by these macrophages. HB-EGF has previously been associated with a number of physiological and pathological conditions, including tumor growth and angiogenesis. The induction of HB-EGF in regulatory macrophages is due to new transcription and not to increased mRNA stability. The transcription factor Sp1 is a major factor in HB-EGF production, and knockdown of Sp1 substantially diminishes HB-EGF production. Sp1 was recruited to three sites within the first 2 kb of the HB-EGF promoter following stimulation, and the site located at -83/-54 was required for HB-EGF promoter activity. These regions of the promoter become more accessible to endonuclease activity following macrophage activation, and this accessibility was contingent on activation of the MAPK, ERK. We show that several experimental manipulations that give rise to regulatory macrophages also result in HB-EGF production. These observations indicate that in addition to the secretion of the anti-inflammatory cytokine IL-10, another novel characteristic of regulatory macrophages is the production of angiogenic HB-EGF.
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Affiliation(s)
- Justin P Edwards
- Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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Sastre AP, Grossmann S, Reusch HP, Schaefer M. Requirement of an intermediate gene expression for biphasic ERK1/2 activation in thrombin-stimulated vascular smooth muscle cells. J Biol Chem 2008; 283:25871-8. [PMID: 18650426 DOI: 10.1074/jbc.m800949200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The expression of contractile proteins in vascular smooth muscle cells is controlled by still poorly defined mechanisms. A thrombin-inducible expression of smooth muscle-specific alpha-actin and myosin heavy chain requires transactivation of the epidermal growth factor (EGF) receptor and a biphasic activation of ERK1/2. Here we demonstrate that the sustained second phase of ERK1/2 phosphorylation requires de novo RNA and protein synthesis. Depolymerization of the actin cytoskeleton by cytochalasin D or disruption of transit between the endoplasmic reticulum and the Golgi apparatus by brefeldin A prevented the second phase of ERK1/2 phosphorylation. We thus conclude that synthesis and trafficking of a plasma membrane-resident protein may be critical intermediates. Analysis of the expression of protease-activated receptor 1, heparin-binding EGF (HB-EGF), and the EGF receptor revealed that pro-HB-EGF is significantly up-regulated upon thrombin stimulation. The kinetic of HB-EGF expression closely matched that of the second phase of ERK1/2 phosphorylation. Because inhibition of matrix metalloproteases or of the EGF receptor strongly attenuated the late phase of ERK1/2 phosphorylation, the second phase of ERK1/2 activation is primarily relayed by shedding of EGF receptor ligands. The small interfering RNA-mediated knockdown of HB-EGF expression confirmed an important role of HB-EGF expression in triggering the second phase of ERK1/2 activation. Confocal imaging of a yellow fluorescent protein-tagged HB-EGF construct demonstrates the rapid plasma membrane integration of the newly synthesized protein. These data imply that the hormonal control of contractile protein expression relies on an intermediate HB-EGF expression to sustain the signaling strength within the Ras/Raf/MEK/ERK cascade.
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Affiliation(s)
- Alejandra Pérez Sastre
- Charité-Universitätsmedizin Berlin, Division of Molecular Pharmacology and Cell Biology, Thielallee 67-73, 14195 Berlin, Germany
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