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Bates PJ, Reyes-Reyes EM, Malik MT, Murphy EM, O'Toole MG, Trent JO. G-quadruplex oligonucleotide AS1411 as a cancer-targeting agent: Uses and mechanisms. Biochim Biophys Acta Gen Subj 2017; 1861:1414-1428. [PMID: 28007579 DOI: 10.1016/j.bbagen.2016.12.015] [Citation(s) in RCA: 201] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 12/16/2016] [Accepted: 12/17/2016] [Indexed: 02/08/2023]
Abstract
BACKGROUND AS1411 is a 26-mer G-rich DNA oligonucleotide that forms a variety of G-quadruplex structures. It was identified based on its cancer-selective antiproliferative activity and subsequently determined to be an aptamer to nucleolin, a multifunctional protein that preferentially binds quadruplex nucleic acids and which is present at high levels on the surface of cancer cells. AS1411 has exceptionally efficient cellular internalization compared to non-quadruplex DNA sequences. SCOPE OF REVIEW Recent developments related to AS1411 will be examined, with a focus on its use for targeted delivery of therapeutic and imaging agents. MAJOR CONCLUSIONS Numerous research groups have used AS1411 as a targeting agent to deliver nanoparticles, oligonucleotides, and small molecules into cancer cells. Studies in animal models have demonstrated that AS1411-linked materials can accumulate selectively in tumors following systemic administration. The mechanism underlying the cancer-targeting ability of AS1411 is not completely understood, but recent studies suggest a model that involves: (1) initial uptake by macropinocytosis, a form of endocytosis prevalent in cancer cells; (2) stimulation of macropinocytosis by a nucleolin-dependent mechanism resulting in further uptake; and (3) disruption of nucleolin-mediated trafficking and efflux leading to cargoes becoming trapped inside cancer cells. SIGNIFICANCE Human trials have indicated that AS1411 is safe and can induce durable remissions in a few patients, but new strategies are needed to maximize its clinical impact. A better understanding of the mechanisms by which AS1411 targets and kills cancer cells may hasten the development of promising technologies using AS1411-linked nanoparticles or conjugates for cancer-targeted therapy and imaging. This article is part of a Special Issue entitled "G-quadruplex" Guest Editor: Dr. Concetta Giancola and Dr. Daniela Montesarchio.
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Affiliation(s)
- Paula J Bates
- Department of Medicine, University of Louisville, USA; James Graham Brown Cancer Center, University of Louisville, USA.
| | | | - Mohammad T Malik
- Department of Medicine, University of Louisville, USA; James Graham Brown Cancer Center, University of Louisville, USA
| | - Emily M Murphy
- Department of Biomedical Engineering, University of Louisville, USA
| | - Martin G O'Toole
- Department of Biomedical Engineering, University of Louisville, USA
| | - John O Trent
- Department of Medicine, University of Louisville, USA; James Graham Brown Cancer Center, University of Louisville, USA
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Lasecka L, Baron MD. The molecular biology of nairoviruses, an emerging group of tick-borne arboviruses. Arch Virol 2014; 159:1249-65. [PMID: 24327094 PMCID: PMC7087186 DOI: 10.1007/s00705-013-1940-z] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2013] [Accepted: 10/30/2013] [Indexed: 12/24/2022]
Abstract
The nairoviruses are a rapidly emerging group of tick-borne bunyaviruses that includes pathogens of humans (Crimean-Congo hemorrhagic fever virus [CCHFV]) and livestock (Nairobi sheep disease virus [NSDV], also known as Ganjam virus), as well as a large number of viruses for which the normal vertebrate host has not been established. Studies on this group of viruses have been fairly limited, not least because CCHFV is a BSL4 human pathogen, restricting the number of labs able to study the live virus, while NSDV, although highly pathogenic in naive animals, is not seen as a threat in developed countries, making it a low priority. Nevertheless, recent years have seen significant progress in our understanding of the biology of these viruses, particularly that of CCHFV, and this article seeks to draw together our existing knowledge to generate an overall picture of their molecular biology, underlining areas of particular ignorance for future studies.
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Affiliation(s)
- Lidia Lasecka
- The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF UK
| | - Michael D. Baron
- The Pirbright Institute, Ash Road, Pirbright, Surrey, GU24 0NF UK
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3
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Fraisier C, Rodrigues R, Vu Hai V, Belghazi M, Bourdon S, Paranhos-Baccala G, Camoin L, Almeras L, Peyrefitte CN. Hepatocyte pathway alterations in response to in vitro Crimean Congo hemorrhagic fever virus infection. Virus Res 2014; 179:187-203. [DOI: 10.1016/j.virusres.2013.10.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 10/20/2013] [Accepted: 10/21/2013] [Indexed: 10/26/2022]
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Abstract
Nucleolin is a multifunctional protein localized primarily in the nucleolus, but also found in the nucleoplasm, cytoplasm and cell membrane. It is involved in several aspects of DNA metabolism, and participates extensively in RNA regulatory mechanisms, including transcription, ribosome assembly, mRNA stability and translation, and microRNA processing. Nucleolin's implication in disease is linked to its ability to associate with target RNAs via its four RNA-binding domains and its arginine/glycin-rich domain. By modulating the post-transcriptional fate of target mRNAs, which typically bear AU-rich and/or G-rich elements, nucleolin has been linked to cellular events that influence disease, notably cell proliferation and protection against apoptotic death. Through its diverse RNA functions, nucleolin is increasingly implicated in pathological processes, particularly cancer and viral infection. Here, we review the RNA-binding activities of nucleolin, its influence on gene expression patterns, and its impact upon diseases. We also discuss the rising interest in targeting nucleolin therapeutically.
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Affiliation(s)
- Kotb Abdelmohsen
- Laboratory of Molecular Biology and Immunology, National Institute on Aging-Intramural Research Program, National Institutes of Health, Baltimore, MD, USA.
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5
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Xiao X, Feng Y, Zhu Z, Dimitrov DS. Identification of a putative Crimean-Congo hemorrhagic fever virus entry factor. Biochem Biophys Res Commun 2011; 411:253-8. [PMID: 21723257 PMCID: PMC3155881 DOI: 10.1016/j.bbrc.2011.06.109] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 06/16/2011] [Indexed: 12/11/2022]
Abstract
Entry of enveloped viruses into cells is initiated by binding of their envelope glycoproteins (Envs) to cell surface-associated receptors. The Crimean-Congo hemorrhagic fever virus (CCHFV) has two Envs, Gn and Gc, with poorly understood role in binding to susceptible cells. We expressed codon optimized Gn and Gc, and identified independently folded soluble Env fragments, one of which (Gc residues 180-300) bound CCHFV susceptible cells supposedly by interacting with a putative receptor. This receptor binding domain (RBD) was used to identify its interacting partner by coimmunoprecipitation and mass spectrometry. Thus we identified the human cell surface nucleolin as a putative CCHFV entry factor. Nucleolin was expressed on all susceptible cells tested but not on the surface of cells resistant to CCHFV infection. Further studies are needed to explore the nucleolin function as a plausible CCHFV receptor and the molecular mechanisms of the Gc-nucleolin interactions. The identification of the CCHFV RBD and its binding partner could provide novel targets for therapy and tools for prevention as well as more complete understanding of the mechanisms of CCHFV entry and pathogenesis.
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Affiliation(s)
- Xiaodong Xiao
- Protein Interactions Group, CCR Nanobiology Program, NCI-Frederick, NIH, Frederick, MD 21702, USA
| | - Yang Feng
- Protein Interactions Group, CCR Nanobiology Program, NCI-Frederick, NIH, Frederick, MD 21702, USA
| | - Zhongyu Zhu
- Protein Interactions Group, CCR Nanobiology Program, NCI-Frederick, NIH, Frederick, MD 21702, USA
| | - Dimiter S. Dimitrov
- Protein Interactions Group, CCR Nanobiology Program, NCI-Frederick, NIH, Frederick, MD 21702, USA
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6
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Legrand D, Vigié K, Said EA, Elass E, Masson M, Slomianny MC, Carpentier M, Briand JP, Mazurier J, Hovanessian AG. Surface nucleolin participates in both the binding and endocytosis of lactoferrin in target cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 2004; 271:303-17. [PMID: 14717698 DOI: 10.1046/j.1432-1033.2003.03929.x] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Lactoferrin (Lf), a multifunctional molecule present in mammalian secretions and blood, plays important roles in host defense and cancer. Indeed, Lf has been reported to inhibit the proliferation of cancerous mammary gland epithelial cells and manifest a potent antiviral activity against human immunodeficiency virus and human cytomegalovirus. The Lf-binding sites on the cell surface appear to be proteoglycans and other as yet undefined protein(s). Here, we isolated a Lf-binding 105 kDa molecular mass protein from cell extracts and identified it as human nucleolin. Medium-affinity interactions ( approximately 240 nm) between Lf and purified nucleolin were further illustrated by surface plasmon resonance assays. The interaction of Lf with the cell surface-expressed nucleolin was then demonstrated through competitive binding studies between Lf and the anti-human immunodeficiency virus pseudopeptide, HB-19, which binds specifically surface-expressed nucleolin independently of proteoglycans. Interestingly, binding competition studies between HB-19 and various Lf derivatives in proteoglycan-deficient hamster cells suggested that the nucleolin-binding site is located in both the N- and C-terminal lobes of Lf, whereas the basic N-terminal region is dispensable. On intact cells, Lf co-localizes with surface nucleolin and together they become internalized through vesicles of the recycling/degradation pathway by an active process. Morever, a small proportion of Lf appears to translocate in the nucleus of cells. Finally, the observations that endocytosis of Lf is inhibited by the HB-19 pseudopeptide, and the lack of Lf endocytosis in proteoglycan-deficient cells despite Lf binding, point out that both nucleolin and proteoglycans are implicated in the mechanism of Lf endocytosis.
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Affiliation(s)
- Dominique Legrand
- Institut Fédératif de Recherche n degrees 118, Université des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
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7
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Nisole S, Krust B, Hovanessian AG. Anchorage of HIV on permissive cells leads to coaggregation of viral particles with surface nucleolin at membrane raft microdomains. Exp Cell Res 2002; 276:155-73. [PMID: 12027446 DOI: 10.1006/excr.2002.5522] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cross-linking of HIV on permissive cells results aggregation of HIV particles with surface nucleolin, CD4, and CXCR4, but without affecting the organization of CD45. In addition, HIV particles and nucleolin coaggregate with glycolipid-enriched membrane microdomains (GEMs) containing ganglioside, and glycosylphosphatidylinositol-linked proteins CD90 and CD59, pointing out that HIV anchorage induces lateral assemblies of specific membrane components into lipid rafts in which surface nucleolin is also incorporated. Consequently, equilibrium density fractionation of extracts from infected cells revealed that HIV proteins and nucleolin copurify with Triton X-100-resistant GEM-associated proteins. After HIV entry, nucleolin is recovered also in fractions containing HIV DNA, viral matrix, and reverse transcriptase, thus suggesting that it could accompany viral entry. We show that surface nucleolin is markedly down-regulated a few hours following HIV entry into permissive cells; an effect that appears to be the consequence of its translocation into the cytoplasm. Our findings demonstrate that anchorage of HIV particles on permissive cells induces aggegation of surface nucleolin and its association with detergent-insoluble lipid raft components. Moreover, they support the suggestion that surface nucleolin and lipid rafts are implicated in early events in the HIV entry process.
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Affiliation(s)
- Sébastien Nisole
- Unité de Virologie et Immunologie Cellulaire, URA 1930 CNRS, Institut Pasteur, Paris, France
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8
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Nisole S, Said EA, Mische C, Prevost MC, Krust B, Bouvet P, Bianco A, Briand JP, Hovanessian AG. The anti-HIV pentameric pseudopeptide HB-19 binds the C-terminal end of nucleolin and prevents anchorage of virus particles in the plasma membrane of target cells. J Biol Chem 2002; 277:20877-86. [PMID: 11919179 DOI: 10.1074/jbc.m110024200] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The multivalent pseudopeptide HB-19 that binds the cell-surface-expressed nucleolin is a potent inhibitor of human immunodeficiency virus (HIV) infection by blocking virus particle attachment and thus anchorage in the plasma membrane. We show that cross-linking of surface-bound HB-19A (like HB-19 but with a modified template) results in aggregation of HB-19A with surface nucleolin. Consistent with its specific action, HB-19A binding to different types of cells reaches saturation at concentrations that have been reported to result in inhibition of HIV infection. By using Chinese hamster ovary mutant cell lines, we confirm that the binding of HB-19A to surface nucleolin is independent of heparan and chondroitin sulfate proteoglycans. In vitro generated full-length nucleolin was found to bind HB-19A, whereas the N-terminal part containing the acidic amino acid stretches of nucleolin did not. The use of various deletion constructs of the C-terminal part of nucleolin then permitted the identification of the extreme C-terminal end of nucleolin, containing repeats of the amino acid motif, RGG, as the domain that binds HB-19A. Finally, a synthetic peptide corresponding to the last C-terminal 63 amino acids was able to inhibit HIV infection at the stage of HIV attachment to cells, thus suggesting that this domain could be functional in the HIV anchorage process.
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Affiliation(s)
- Sébastien Nisole
- Unité de Virologie et Immunologie Cellulaire (URA 1930 CNRS), Plateau Technique, Institut Pasteur, 28 Rue du Dr. Roux, 75724 Paris Cedex 15, France
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9
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Krust B, Vienet R, Cardona A, Rougeot C, Jacotot E, Callebaut C, Guichard G, Briand JP, Grognet JM, Hovanessian AG, Edelman L. The anti-HIV pentameric pseudopeptide HB-19 is preferentially taken up in vivo by lymphoid organs where it forms a complex with nucleolin. Proc Natl Acad Sci U S A 2001; 98:14090-5. [PMID: 11698640 PMCID: PMC61173 DOI: 10.1073/pnas.221467298] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2001] [Accepted: 09/04/2001] [Indexed: 11/18/2022] Open
Abstract
The HB-19 pseudopeptide 5[Kpsi(CH(2)N)PR]-TASP, psi(CH(2)N) for reduced peptide bond, is a specific inhibitor of HIV infection in different CD4(+) cell lines and in primary T-lymphocytes and macrophages. It blocks virus-particle attachment to permissive cells by binding and forming a stable complex with nucleolin expressed on the cell surface. Here, we have investigated the tissue distribution of the tritiated HB-19 by using beta-radio imager whole-body mapping in rats. A rapid, selective, and stable distribution and accumulation of the systematically administered HB-19 was demonstrated within the spleen, liver, bone, and kidney as soon as 5 min following its administration. No apparent uptake of HB-19 occurred in the brain and the muscle tissue. Interestingly and despite its rapid clearance from the blood, at 24 h postexposure a significant proportion of HB-19 was still recovered from target organs, of which 16-37% could be accounted for intact pseudopeptide. The elimination of HB-19 mainly occurred by renal glomerular filtration and most of the excreted radioactivity appeared to be HB-19 metabolites. Finally, injection of the biotin-labeled HB-19 pseudopeptide but not its control counterpart allowed the recovery of the HB-19-nucleolin complex from the liver, spleen, thymus, and bone marrow, thus indicating that the in vivo molecular target of HB-19 is surface nucleolin. Our results demonstrate the preferential uptake and stability of HB-19 in lymphoid organs that are the site of HIV propagation.
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Affiliation(s)
- B Krust
- Unité de Virologie et Immunologie Cellulaire, Unité de Recherche Associée 1930 Centre National de Recherche Scientifique (CNRS), 28 Rue du Dr Roux, 75714 Paris Cedex 15, France
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10
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Babcock GJ, Mirzabekov T, Wojtowicz W, Sodroski J. Ligand binding characteristics of CXCR4 incorporated into paramagnetic proteoliposomes. J Biol Chem 2001; 276:38433-40. [PMID: 11489906 DOI: 10.1074/jbc.m106229200] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The G protein-coupled receptor CXCR4 is a coreceptor, along with CD4, for the human immunodeficiency virus type 1 (HIV-1) and has been implicated in breast cancer metastasis. We studied the binding of the HIV-1 gp120 envelope glycoprotein (gp) to CXCR4 but found that the gp120s from CXCR4-using HIV-1 strains bound nonspecifically to several cell lines lacking human CXCR4 expression. Therefore, we constructed paramagnetic proteoliposomes (CXCR4-PMPLs) containing pure, native CXCR4. CXCR4-PMPLs specifically bound the natural ligand, SDF-1alpha, and the gp120s from CXCR4-using HIV-1 strains. Conformation-dependent anti-CXCR4 antibodies and the CXCR4 antagonist AMD3100 blocked HIV-1 gp120 binding to CXCR4-PMPLs. The gp120-CXCR4 interaction was blocked by anti-gp120 antibodies directed against the third variable (V3) loop and CD4-induced epitopes, structures that have also been implicated in the binding of gp120 to the other HIV-1 coreceptor, CCR5. Compared with the binding of R5 HIV-1 gp120s to CCR5, the gp120-CXCR4 interaction exhibited a lower affinity (K(d) = 200 nm) and was dependent upon prior CD4 binding, even at low temperature. Thus, although similar regions of X4 and R5 HIV-1 gp120s appear to be involved in binding CXCR4 and CCR5, respectively, differences exist in nonspecific binding to cell surfaces, affinity for the chemokine receptor, and CD4 dependence at low temperature.
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Affiliation(s)
- G J Babcock
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, the Harvard Medical School, Boston, Massachusetts 02115, USA
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11
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Callebaut C, Nisole S, Briand JP, Krust B, Hovanessian AG. Inhibition of HIV infection by the cytokine midkine. Virology 2001; 281:248-64. [PMID: 11277697 DOI: 10.1006/viro.2000.0767] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The growth factor midkine (MK) has been reported to bind heparan sulfate and nucleolin, two components of the cell surface implicated in the attachment of HIV-1 particles. Here we show that synthetic and recombinant preparations of MK inhibit in a dose-dependent manner infection of cells by T-lymphocyte- and macrophage-tropic HIV-1 isolates. The binding of labeled MK to cells is prevented by excess unlabeled MK or by the anti-HIV pseudopeptide HB-19 that blocks HIV entry by forming a stable complex with the cell-surface-expressed nucleolin. MK mRNA is systematically expressed in adult peripheral blood lymphocytes from healthy donors, while its expression becomes markedly but transiently increased upon in vitro treatment of lymphocytes with IL-2 or IFN-gamma and activation of T-lymphocytes by PHA or antibodies specific to CD3/CD28. In MK-producing lymphocytes, MK is detectable at the cell surface where it colocalizes with the surface-expressed nucleolin. Finally, by using MK-producing CD4(+) and CD4(-) cell clones we show that HIV infection in cell cultures could be inhibited in both an autocrine and a paracrine manner. The potent and distinct anti-HIV action of MK along with its enhanced expression in lymphocytes by various physiological stimuli suggests that MK is a cytokine that could be implicated in HIV-induced pathogenesis.
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Affiliation(s)
- C Callebaut
- Unité de Virologie et Immunologie Cellulaire, URA 1930 CNRS, Institut Pasteur, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France
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12
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Hovanessian AG, Puvion-Dutilleul F, Nisole S, Svab J, Perret E, Deng JS, Krust B. The cell-surface-expressed nucleolin is associated with the actin cytoskeleton. Exp Cell Res 2000; 261:312-28. [PMID: 11112338 DOI: 10.1006/excr.2000.5071] [Citation(s) in RCA: 181] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nucleolin is a RNA- and protein-binding multifunctional protein. Mainly characterized as a nucleolar protein, nucleolin is continuously expressed on the surface of different types of cells along with its intracellular pool within the nucleus and cytoplasm. By confocal and electron microscopy using specific antibodies against nucleolin, we show that cytoplasmic nucleolin is found in small vesicles that appear to translocate nucleolin to the cell surface. Translocation of nucleolin is markedly reduced at low temperature or in serum-free medium, whereas conventional inhibitors of intracellular glycoprotein transport have no effect. Thus, translocation of nucleolin is the consequence of an active transport by a pathway which is independent of the endoplasmic reticulum-Golgi complex. The cell-surface-expressed nucleolin becomes clustered at the external side of the plasma membrane when cross-linked by the nucleolin-specific monoclonal antibody mAb D3. This clustering, occurring at 20 degrees C and in a well-organized pattern, is dependent on the existence of an intact actin cytoskeleton. At 37 degrees C, mAb D3 becomes internalized, thus illustrating that surface nucleolin can mediate intracellular import of specific ligands. Our results point out that nucleolin should also be considered a component of the cell surface where it could be functional as a cell surface receptor for various ligands reported before.
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Affiliation(s)
- A G Hovanessian
- Unité de Virologie et Immunologie Cellulaire, URA 1930 CNRS, 28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
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13
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Garcia RC, Banfi E, Pittis MG. Infection of macrophage-like THP-1 cells with Mycobacterium avium results in a decrease in their ability to phosphorylate nucleolin. Infect Immun 2000; 68:3121-8. [PMID: 10816453 PMCID: PMC97542 DOI: 10.1128/iai.68.6.3121-3128.2000] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/1999] [Accepted: 02/29/2000] [Indexed: 11/20/2022] Open
Abstract
This study of the phosphorylation ability of macrophage-like cells upon infection with Mycobacterium avium was undertaken to establish potential targets of the interference with host response mechanisms. Cytosolic and membrane fractions from noninfected and infected cells were incubated with [gamma-(32)P]ATP, in the presence of Mg(2+) and the absence of Ca(2+), and the patterns of phosphoproteins synthesized were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Lower levels of a 110-kDa phosphoprotein were observed in association with cytosolic fractions from mycobacterium-infected cells compared to noninfected cells or cells treated with lipopolysaccharide or having ingested Escherichia coli or killed M. avium. The 110-kDa phosphoprotein was present in the soluble fraction (230,000 x g supernatant) after the kinase incubation, from where it was partially purified and identified as phosphonucleolin by amino acid sequencing. The decrease in nucleolin phosphorylation observed was not related to changes in the cytosolic or membrane levels of this protein, and was detected also in the cytosolic fraction of (32)P-labeled intact cells.
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Affiliation(s)
- R C Garcia
- Leukocyte Biology Unit, International Centre for Genetic Engineering and Biotechnology, Area Science Park, 34012 Trieste, Italy.
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14
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Cabrera C, Gutiérrez A, Blanco J, Barretina J, Litovchick A, Lapidot A, Evdokimov AG, Clotet B, Esté JA. Anti-human immunodeficiency virus activity of novel aminoglycoside-arginine conjugates at early stages of infection. AIDS Res Hum Retroviruses 2000; 16:627-34. [PMID: 10791873 DOI: 10.1089/088922200308855] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Conjugates of L-arginine with aminoglycosides have already been described as potent in vitro inhibitors of the HIV-1 Tat-trans-activation responsive element interaction. The polycationic nature of these agents leads us to suggest that they may be active against HIV-1 replication by inhibiting earlier stages of the virus life cycle. We have found that R4K and R3G, kanamycin A, and gentamicin C, conjugated with arginine, inhibited HIV-1 NL4-3 replication at EC50 values of 15 and 30 microM for R3G and R4K, respectively, without a detectable tonic effect on MT-4 cells at concentrations higher than 4000 and about 1000 microM, respectively. Both compounds inhibited the binding of a monoclonal antibody (12G5) directed to CXCR4 as well as the intracellular Ca2+ signal induced by the chemokine SDF-1alpha on CXCR4+ cells, suggesting that aminoglycoside-arginine conjugates interact with CXCR4, the coreceptor used by T-tropic, X4 strains of HIV-1. On the other hand, CB4K, a conjugate of kanamycin A with gamma-guanidinobutyric acid, structurally similar to R4K, failed to display any anti-HIV activity of CXCR4 antagonist activity. An HIV-1 strain that was made resistant to the known CXCR4 antagonist AMD3100 was cross-resistant to both R4K and R3G. However, unlike SDF-1alpha and R4K, R3G inhibited the binding of HIV-1 to MT-4 cells. Aminoglycoside-arginine conjugates inhibit HIV replication by interrupting the early phase of the virus life cycle, namely virus binding to CD4 cells and interaction with CXCR4. R3G and R4K may serve as prototypes of novel anti-HIV agents and should be further studied.
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Affiliation(s)
- C Cabrera
- Institut de Recerca de la SIDA-Caixa (irsiCaixa), Retrovirology Laboratory, Hospital Universitari Germans Trias i Pujol, Badalona, Spain
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15
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Nisole S, Krust B, Dam E, Bianco A, Seddiki N, Loaec S, Callebaut C, Guichard G, Muller S, Briand JP, Hovanessian AG. The HB-19 pseudopeptide 5[Kpsi(CH2N)PR]-TASP inhibits attachment of T lymophocyte- and macrophage-tropic HIV to permissive cells. AIDS Res Hum Retroviruses 2000; 16:237-49. [PMID: 10710212 DOI: 10.1089/088922200309331] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
Abstract
The HB-19 pseudopeptide 5[Kpsi(CH2N)PR]-TASP[psi(CH2N) indicating a reduced peptide bond], which binds the cell surface-expressed nucleolin, is a potent inhibitor of HIV infection. Here, by using primary T lymphocyte cultures and an experimental cell model to monitor HIV entry, we show that HB-19 inhibits in a dose-dependent manner both T lymphocyte- and macrophage-tropic HIV isolates. Similar positively charged control pseudopeptides have no effect on HIV infection even at high concentrations. These observations, and the fact that HB-19 has no effect on SIV-mac and HIV-1 pseudotyped with VSV envelope glycoproteins, confirm the specific nature of this inhibitor against the entry process mediated by the HIV envelope glycoproteins. Finally, association of low doses of HB-19 with beta-chemokines or AZT results in an increased inhibitory effect on HIV infection. HB-19 has no inhibitory effect when added to cells a few hours after HIV entry. On the other hand, in HB-19-pretreated cells, the inhibitory effect persists for several hours, even after washing cells to remove away the unbound pseudopeptide. Under such conditions, the attachment of HIV particles to cells is inhibited as efficiently as by neutralizing monoclonal antibodies directed against the V3 loop. In view of its specific mode of action on various HIV isolates, HB-19 represents a potential anti-HIV drug.
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Affiliation(s)
- S Nisole
- Unité de Virologie et Immunologie Cellulaire, URA CNRS 1930, Institut Pasteur, Paris, France
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16
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Nisole S, Krust B, Callebaut C, Guichard G, Muller S, Briand JP, Hovanessian AG. The anti-HIV pseudopeptide HB-19 forms a complex with the cell-surface-expressed nucleolin independent of heparan sulfate proteoglycans. J Biol Chem 1999; 274:27875-84. [PMID: 10488134 DOI: 10.1074/jbc.274.39.27875] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The HB-19 pseudopeptide 5[Kpsi(CH(2)N)PR]-TASP, psi(CH(2)N) for reduced peptide bond, is a specific inhibitor of human immunodeficiency virus (HIV) infection in different CD4(+) cell lines and in primary T-lymphocytes and macrophages. Here, by using an experimental CD4(+) cell model to monitor HIV entry and infection, we demonstrate that HB-19 binds the cell surface and inhibits attachment of HIV particles to permissive cells. At concentrations that inhibit HIV attachment, HB-19 binds cells irreversibly, becomes complexed with the cell-surface-expressed nucleolin, and eventually results in its degradation. Accordingly, by confocal immunofluorescence microscopy, we demonstrate the drastic reduction of the cell-surface-expressed nucleolin following treatment of cells with HB-19. HIV particles can prevent the binding of HB-19 to cells and inhibit complex formation with nucleolin. Such a competition between viral particles and HB-19 is consistent with the implication of nucleolin in the process of HIV attachment to target cells. We show that another inhibitor of HIV infection, the fibroblast growth factor-2 (FGF-2) that uses cell-surface-expressed heparan sulfate proteoglycans as low affinity receptors, binds cells and blocks attachment of HIV to permissive cells. FGF-2 does not prevent the binding of HB-19 to cells and to nucleolin, and similarly HB-19 has no apparent effect on the binding of FGF-2 to the cell surface. The lack of competition between these two anti-HIV agents rules out the potential involvement of heparan sulfate proteoglycans in the mechanism of anti-HIV effect of HB-19, thus pointing out that nucleolin is its main target.
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Affiliation(s)
- S Nisole
- Unité de Virologie et Immunologie Cellulaire, URA 1930 CNRS, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
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