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Moriya A, Otsuka K, Naoi R, Terahata M, Takeda K, Kondo S, Adachi-Yamada T. Creation of Knock-In Alleles of Insulin Receptor Tagged by Fluorescent Proteins mCherry or EYFP in Fruit Fly Drosophila melanogaster. Zoolog Sci 2024; 41:230-243. [PMID: 38587918 DOI: 10.2108/zs230075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 12/19/2023] [Indexed: 04/10/2024]
Abstract
The insulin/insulin-like growth factor-like signaling (IIS) pathway is highly conserved across metazoans and regulates numerous physiological functions, including development, metabolism, fecundity, and lifespan. The insulin receptor (InR), a crucial membrane receptor in the IIS pathway, is known to be ubiquitously expressed in various tissues, albeit at generally low levels, and its subcellular localization remains incompletely characterized. In this study, we employed CRISPR-mediated mutagenesis in the fruit fly Drosophila to create knock-in alleles of InR tagged with fluorescent proteins (InR::mCherry or InR::EYFP). By inserting the coding sequence of the fluorescent proteins mCherry or EYFP near the end of the coding sequence of the endogenous InR gene, we could trace the natural InR protein through their fluorescence. As an example, we investigated epithelial cells of the male accessory gland (AG), an internal reproductive organ, and identified two distinct patterns of InR::mCherry localization. In young AG, InR::mCherry accumulated on the basal plasma membrane between cells, whereas in mature AG, it exhibited intracellular localization as multiple puncta, indicating endocytic recycling of InR during cell growth. In the AG senescence accelerated by the mutation of Diuretic hormone 31 (Dh31), the presence of InR::mCherry puncta was more pronounced compared to the wild type. These findings raise expectations for the utility of the newly created InR::mCherry/EYFP alleles for studying the precise expression levels and subcellular localization of InR. Furthermore, this fluorescently tagged allele approach can be extended to investigate other membrane receptors with low abundance, facilitating the direct examination of their true expression and localization.
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Affiliation(s)
- Ayano Moriya
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
| | - Kei Otsuka
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
- Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
| | - Riku Naoi
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
| | - Mayu Terahata
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
| | - Koji Takeda
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
- Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
| | - Shu Kondo
- Department of Biological Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science, Katsushika-ku, Tokyo 125-8585, Japan
| | - Takashi Adachi-Yamada
- Graduate Course in Life Science, Graduate School of Science, Gakushuin University, Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan,
- Department of Life Science, Faculty of Science, Gakushuin University, Toshima-ku, Tokyo 171-8588, Japan
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2
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Pardridge WM. Brain gene therapy with Trojan horse lipid nanoparticles. Trends Mol Med 2023; 29:343-353. [PMID: 36907687 PMCID: PMC10005896 DOI: 10.1016/j.molmed.2023.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/13/2023]
Abstract
The COVID-19 mRNA vaccine was developed by the scalable manufacture of lipid nanoparticles (LNPs) that encapsulate mRNA within the lipid. There are many potential applications for this large nucleic acid delivery technology, including the delivery of plasmid DNA for gene therapy. However, gene therapy for the brain requires LNP delivery across the blood-brain barrier (BBB). It is proposed that LNPs could be reformulated for brain delivery by conjugation of receptor-specific monoclonal antibodies (MAbs) to the LNP surface. The MAb acts as a molecular Trojan horse to trigger receptor-mediated transcytosis (RMT) of the LNP across the BBB and subsequent localization to the nucleus for transcription of the therapeutic gene. Trojan horse LNPs could enable new approaches to gene therapy of the brain.
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3
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Liu M, Chen MY, An L, Ma SQ, Mei J, Huang WH, Zhang W. Effects of apolipoprotein E on regulating insulin sensitivity via regulating insulin receptor signalosome in caveolae. Life Sci 2022; 308:120929. [PMID: 36063979 DOI: 10.1016/j.lfs.2022.120929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/28/2022] [Accepted: 08/30/2022] [Indexed: 10/31/2022]
Abstract
AIMS Although impaired insulin signaling at a post-receptor level was a well-established key driver of insulin resistance, the role of surface abnormal insulin receptor (INSR) location in insulin resistance pathogenesis tended to be ignored and its molecular mechanisms remained obscure. Herein, this study aimed to investigate hepatic apolipoprotein E (APOE) impaired cellular insulin action via reducing cell surface INSR, especially in caveolae. KEY FINDINGS Downregulation of APOE enhanced the caveolae translocation of INSR and glucose transporter 2 (GLUT2), and improved hepatic cells' sensitivity to insulin. Consistently, mice with selective suppression of liver tissue APOE showed lower fasting insulin and fasting glucose levels, better homeostatic model assessment (HOMA) index (HOMA-IS, HOMA-IR, HOMA-β) and quantitative insulin sensitivity check index (QUICKI). Furthermore, the co-localization of INSR and CAV1 in the liver of these mice were more substantial than controls. SIGNIFICANCE APOE might adversely set the basal gain of INSR signaling implied that APOE could be a new endogenous INSR regulator.
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Affiliation(s)
- Miao Liu
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha 410008, PR China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha 410078, PR China; National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha 410008, Hunan, PR China
| | - Man-Yun Chen
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha 410008, PR China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha 410078, PR China; National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha 410008, Hunan, PR China
| | - Liang An
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha 410008, PR China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha 410078, PR China; National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha 410008, Hunan, PR China
| | - Si-Qing Ma
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha 410008, PR China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha 410078, PR China; National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha 410008, Hunan, PR China
| | - Jie Mei
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha 410008, PR China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha 410078, PR China; National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha 410008, Hunan, PR China
| | - Wei-Hua Huang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha 410008, PR China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha 410078, PR China; National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha 410008, Hunan, PR China; NHC Key Laboratory of Birth Defect for Research and Prevention (Hunan Provincial Maternal and Child Health Care Hospital), Hunan 410008, PR China.
| | - Wei Zhang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha 410008, PR China; Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, 110 Xiangya Road, Changsha 410078, PR China; National Clinical Research Center for Geriatric Disorders, 87 Xiangya Road, Changsha 410008, Hunan, PR China.
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4
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A Historical Review of Brain Drug Delivery. Pharmaceutics 2022; 14:pharmaceutics14061283. [PMID: 35745855 PMCID: PMC9229021 DOI: 10.3390/pharmaceutics14061283] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/01/2022] [Accepted: 06/07/2022] [Indexed: 12/13/2022] Open
Abstract
The history of brain drug delivery is reviewed beginning with the first demonstration, in 1914, that a drug for syphilis, salvarsan, did not enter the brain, due to the presence of a blood-brain barrier (BBB). Owing to restricted transport across the BBB, FDA-approved drugs for the CNS have been generally limited to lipid-soluble small molecules. Drugs that do not cross the BBB can be re-engineered for transport on endogenous BBB carrier-mediated transport and receptor-mediated transport systems, which were identified during the 1970s-1980s. By the 1990s, a multitude of brain drug delivery technologies emerged, including trans-cranial delivery, CSF delivery, BBB disruption, lipid carriers, prodrugs, stem cells, exosomes, nanoparticles, gene therapy, and biologics. The advantages and limitations of each of these brain drug delivery technologies are critically reviewed.
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5
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Class I PI3K Biology. Curr Top Microbiol Immunol 2022; 436:3-49. [DOI: 10.1007/978-3-031-06566-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Werner H, Sarfstein R, Laron Z. The Role of Nuclear Insulin and IGF1 Receptors in Metabolism and Cancer. Biomolecules 2021; 11:biom11040531. [PMID: 33918477 PMCID: PMC8065599 DOI: 10.3390/biom11040531] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/24/2021] [Accepted: 04/01/2021] [Indexed: 12/22/2022] Open
Abstract
Insulin (InsR) and insulin-like growth factor-1 (IGF1R) receptors mediate the metabolic and growth-promoting actions of insulin and IGF1/IGF2, respectively. Evidence accumulated in recent years indicates that, in addition to their typical cell-surface localization pattern and ligand-activated mechanism of action, InsR and IGF1R are present in the cell nucleus of both normal and transformed cells. Nuclear translocation seems to involve interaction with a small, ubiquitin-like modifier protein (SUMO-1), although this modification is not always a prerequisite. Nuclear InsR and IGF1R exhibit a number of biological activities that classically fit within the definition of transcription factors. These nuclear activities include, among others, sequence-specific DNA binding and transcriptional control. Of particular interest, nuclear IGF1R was capable of binding and stimulating its cognate gene promoter. The physiological relevance of this autoregulatory mechanism needs to be further investigated. In addition to its nuclear localization, studies have identified IGF1R in the Golgi apparatus, and this particular distribution correlated with a migratory phenotype. In summary, the newly described roles of InsR and IGF1R as gene regulators, in concert with their atypical pattern of subcellular distribution, add a further layer of complexity to traditional models of cell signaling. Furthermore, and in view of the emerging role of IGF1R as a potential therapeutic target, a better understanding of the mechanisms responsible for nuclear IGF1R transport and identification of IGF1R interactors might help optimize target directed therapies in oncology.
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Affiliation(s)
- Haim Werner
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel;
- Shalom and Varda Yoran Institute for Human Genome Research, Tel Aviv University, Tel Aviv 69978, Israel
- Correspondence:
| | - Rive Sarfstein
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel;
| | - Zvi Laron
- Endocrine and Diabetes Research Unit, Schneider Children’s Medical Center, Petah Tikva 49292, Israel;
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7
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Chen MK, Hsu JL, Hung MC. Nuclear receptor tyrosine kinase transport and functions in cancer. Adv Cancer Res 2020; 147:59-107. [PMID: 32593407 DOI: 10.1016/bs.acr.2020.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Signaling functions of plasma membrane-localized receptor tyrosine kinases (RTKs) have been extensively studied after they were first described in the mid-1980s. Plasma membrane RTKs are activated by extracellular ligands and cellular stress stimuli, and regulate cellular responses by activating the downstream effector proteins to initiate a wide range of signaling cascades in the cells. However, increasing evidence indicates that RTKs can also be transported into the intracellular compartments where they phosphorylate traditional effector proteins and non-canonical substrate proteins. In general, internalization that retains the RTK's transmembrane domain begins with endocytosis, and endosomal RTK remains active before being recycled or degraded. Further RTK retrograde transport from endosome-Golgi-ER to the nucleus is primarily dependent on membranes vesicles and relies on the interaction with the COP-I vesicle complex, Sec61 translocon complex, and importin. Internalized RTKs have non-canonical substrates that include transcriptional co-factors and DNA damage response proteins, and many nuclear RTKs harbor oncogenic properties and can enhance cancer progression. Indeed, nuclear-localized RTKs have been shown to positively correlate with cancer recurrence, therapeutic resistance, and poor prognosis of cancer patients. Therefore, understanding the functions of nuclear RTKs and the mechanisms of nuclear RTK transport will further improve our knowledge to evaluate the potential of targeting nuclear RTKs or the proteins involved in their transport as new cancer therapeutic strategies.
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Affiliation(s)
- Mei-Kuang Chen
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States; The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Jennifer L Hsu
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, United States
| | - Mien-Chie Hung
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, United States; Graduate Institute of Biomedical Sciences, Research Center for Cancer Biology, and Center for Molecular Medicine, China Medical University, Taichung, Taiwan.
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8
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Chen Y, Huang L, Qi X, Chen C. Insulin Receptor Trafficking: Consequences for Insulin Sensitivity and Diabetes. Int J Mol Sci 2019; 20:ijms20205007. [PMID: 31658625 PMCID: PMC6834171 DOI: 10.3390/ijms20205007] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/04/2019] [Accepted: 10/08/2019] [Indexed: 12/12/2022] Open
Abstract
Insulin receptor (INSR) has been extensively studied in the area of cell proliferation and energy metabolism. Impaired INSR activities lead to insulin resistance, the key factor in the pathology of metabolic disorders including type 2 diabetes mellitus (T2DM). The mainstream opinion is that insulin resistance begins at a post-receptor level. The role of INSR activities and trafficking in insulin resistance pathogenesis has been largely ignored. Ligand-activated INSR is internalized and trafficked to early endosome (EE), where INSR is dephosphorylated and sorted. INSR can be subsequently conducted to lysosome for degradation or recycled back to the plasma membrane. The metabolic fate of INSR in cellular events implies the profound influence of INSR on insulin signaling pathways. Disruption of INSR-coupled activities has been identified in a wide range of insulin resistance-related diseases such as T2DM. Accumulating evidence suggests that alterations in INSR trafficking may lead to severe insulin resistance. However, there is very little understanding of how altered INSR activities undermine complex signaling pathways to the development of insulin resistance and T2DM. Here, we focus this review on summarizing previous findings on the molecular pathways of INSR trafficking in normal and diseased states. Through this review, we provide insights into the mechanistic role of INSR intracellular processes and activities in the development of insulin resistance and diabetes.
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Affiliation(s)
- Yang Chen
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia.
| | - Lili Huang
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia.
| | - Xinzhou Qi
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia.
| | - Chen Chen
- School of Biomedical Sciences, The University of Queensland, Brisbane 4072, Australia.
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9
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The NAE Pathway: Autobahn to the Nucleus for Cell Surface Receptors. Cells 2019; 8:cells8080915. [PMID: 31426451 PMCID: PMC6721735 DOI: 10.3390/cells8080915] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/13/2019] [Accepted: 08/13/2019] [Indexed: 12/19/2022] Open
Abstract
Various growth factors and full-length cell surface receptors such as EGFR are translocated from the cell surface to the nucleoplasm, baffling cell biologists to the mechanisms and functions of this process. Elevated levels of nuclear EGFR correlate with poor prognosis in various cancers. In recent years, nuclear EGFR has been implicated in regulating gene transcription, cell proliferation and DNA damage repair. Different models have been proposed to explain how the receptors are transported into the nucleus. However, a clear consensus has yet to be reached. Recently, we described the nuclear envelope associated endosomes (NAE) pathway, which delivers EGFR from the cell surface to the nucleus. This pathway involves transport, docking and fusion of NAEs with the outer membrane of the nuclear envelope. EGFR is then presumed to be transported through the nuclear pore complex, extracted from membranes and solubilised. The SUN1/2 nuclear envelope proteins, Importin-beta, nuclear pore complex proteins and the Sec61 translocon have been implicated in the process. While this framework can explain the cell surface to nucleus traffic of EGFR and other cell surface receptors, it raises several questions that we consider in this review, together with implications for health and disease.
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10
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Vella V, Malaguarnera R, Nicolosi ML, Morrione A, Belfiore A. Insulin/IGF signaling and discoidin domain receptors: An emerging functional connection. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:118522. [PMID: 31394114 DOI: 10.1016/j.bbamcr.2019.118522] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Revised: 07/30/2019] [Accepted: 07/31/2019] [Indexed: 12/28/2022]
Abstract
The insulin/insulin-like growth factor system (IIGFs) plays a fundamental role in the regulation of prenatal and postnatal growth, metabolism and homeostasis. As a consequence, dysregulation of this axis is associated with growth disturbance, type 2 diabetes, chronic inflammation and tumor progression. A functional crosstalk between IIGFs and discoidin domain receptors (DDRs) has been recently discovered. DDRs are non-integrin collagen receptors that canonically undergo slow and long-lasting autophosphorylation after binding to fibrillar collagen. While both DDR1 and DDR2 functionally interact with IIGFs, the crosstalk with DDR1 is so far better characterized. Notably, the IIGFs-DDR1 crosstalk presents a feed-forward mechanism, which does not require collagen binding, thus identifying novel non-canonical action of DDR1. Further studies are needed to fully explore the role of this IIGFs-DDRs functional loop as potential target in the treatment of inflammatory and neoplastic disorders.
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Affiliation(s)
- Veronica Vella
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, Catania, Italy
| | | | - Maria Luisa Nicolosi
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, Catania, Italy
| | - Andrea Morrione
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Antonino Belfiore
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, Catania, Italy.
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11
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Hancock ML, Meyer RC, Mistry M, Khetani RS, Wagschal A, Shin T, Ho Sui SJ, Näär AM, Flanagan JG. Insulin Receptor Associates with Promoters Genome-wide and Regulates Gene Expression. Cell 2019; 177:722-736.e22. [PMID: 30955890 PMCID: PMC6478446 DOI: 10.1016/j.cell.2019.02.030] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 01/07/2019] [Accepted: 02/19/2019] [Indexed: 02/08/2023]
Abstract
Insulin receptor (IR) signaling is central to normal metabolic control and dysregulated in prevalent chronic diseases. IR binds insulin at the cell surface and transduces rapid signaling via cytoplasmic kinases. However, mechanisms mediating long-term effects of insulin remain unclear. Here, we show that IR associates with RNA polymerase II in the nucleus, with striking enrichment at promoters genome-wide. The target genes were highly enriched for insulin-related functions including lipid metabolism and protein synthesis and diseases including diabetes, neurodegeneration, and cancer. IR chromatin binding was increased by insulin and impaired in an insulin-resistant disease model. Promoter binding by IR was mediated by coregulator host cell factor-1 (HCF-1) and transcription factors, revealing an HCF-1-dependent pathway for gene regulation by insulin. These results show that IR interacts with transcriptional machinery at promoters and identify a pathway regulating genes linked to insulin's effects in physiology and disease.
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Affiliation(s)
- Melissa L. Hancock
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA,Present address: John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge,
MA, USA
| | - Rebecca C. Meyer
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA,These authors contributed equally
| | - Meeta Mistry
- Bioinformatics Core, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA,These authors contributed equally
| | - Radhika S. Khetani
- Bioinformatics Core, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA,These authors contributed equally
| | - Alexandre Wagschal
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA,Massachusetts General Hospital Cancer Center, Charlestown, MA 02129, USA,Present address: Exonics Therapeutics, Cambridge, MA, USA
| | - Taehwan Shin
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Shannan J. Ho Sui
- Bioinformatics Core, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Anders M. Näär
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA,Massachusetts General Hospital Cancer Center, Charlestown, MA 02129, USA,Present address: Department of Nutritional Sciences & Toxicology, University of California, Berkeley, CA
94720, USA
| | - John G. Flanagan
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA,Program in Neuroscience, Harvard Medical School, Boston, MA 02115, USA,Lead Contact,Correspondence:
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12
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Kesten D, Horovitz-Fried M, Brutman-Barazani T, Sampson SR. Insulin-induced translocation of IR to the nucleus in insulin responsive cells requires a nuclear translocation sequence. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:551-559. [PMID: 29317261 DOI: 10.1016/j.bbamcr.2018.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 01/03/2018] [Accepted: 01/04/2018] [Indexed: 02/02/2023]
Abstract
Insulin binding to its cell surface receptor (IR) activates a cascade of events leading to its biological effects. The Insulin-IR complex is rapidly internalized and then is either recycled back to the plasma membrane or sent to lysosomes for degradation. Although most of the receptor is recycled or degraded, a small amount may escape this pathway and migrate to the nucleus of the cell where it might be important in promulgation of receptor signals. In this study we explored the mechanism by which insulin induces IR translocation to the cell nucleus. Experiments were performed cultured L6 myoblasts, AML liver cells and 3T3-L1 adipocytes. Insulin treatment induced a rapid increase in nuclear IR protein levels within 2 to 5 min. Treatment with WGA, an inhibitor of nuclear import, reduced insulin-induced increases nuclear IR protein; IR was, however, translocated to a perinuclear location. Bioinformatics tools predicted a potential nuclear localization sequence (NLS) on IR. Immunofluorescence staining showed that a point mutation on the predicted NLS blocked insulin-induced IR nuclear translocation. In addition, blockade of nuclear IR activation in isolated nuclei by an IR blocking antibody abrogated insulin-induced increases in IR tyrosine phosphorylation and nuclear PKCδ levels. Furthermore, over expression of mutated IR reduced insulin-induced glucose uptake and PKB phosphorylation. When added to isolated nuclei, insulin induced IR phosphorylation but had no effect on nuclear IR protein levels. These results raise questions regarding the possible role of nuclear IR in IR signaling and insulin resistance.
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Affiliation(s)
- Dov Kesten
- Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel
| | | | | | - Sanford R Sampson
- Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900, Israel; Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel.
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13
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Zhou Y, Wang X, Cao T, Xu J, Wang D, Restrepo D, Li A. Insulin Modulates Neural Activity of Pyramidal Neurons in the Anterior Piriform Cortex. Front Cell Neurosci 2017; 11:378. [PMID: 29234275 PMCID: PMC5712367 DOI: 10.3389/fncel.2017.00378] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 11/13/2017] [Indexed: 01/12/2023] Open
Abstract
Insulin is an important peptide hormone that regulates food intake and olfactory function. While a multitude of studies investigated the effect of insulin in the olfactory bulb and olfactory epithelium, research on how it modulates higher olfactory centers is lacking. Here we investigate how insulin modulates neural activity of pyramidal neurons in the anterior piriform cortex, a key olfactory signal processing center that plays important roles in odor perception, preference learning, and odor pattern separation. In vitro we find from brain slice recordings that insulin increases the excitation of pyramidal neurons, and excitatory synaptic transmission while it decreases inhibitory synaptic transmission. In vivo local field potential (LFP) recordings indicate that insulin decreases both ongoing gamma oscillations and odor evoked beta responses. Moreover, recordings of calcium activity from pyramidal neurons reveal that insulin modulates the odor-evoked responses by an inhibitory effect. These results indicate that insulin alters olfactory signal processing in the anterior piriform cortex.
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Affiliation(s)
- Yang Zhou
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Xiaojie Wang
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Tiantian Cao
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Jinshan Xu
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Dejuan Wang
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
| | - Diego Restrepo
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Anan Li
- Jiangsu Key Laboratory of Brain Disease and Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical University, Xuzhou, China
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Expression and role of TYRO3 and AXL as potential therapeutical targets in leiomyosarcoma. Br J Cancer 2017; 117:1787-1797. [PMID: 29024938 PMCID: PMC5729471 DOI: 10.1038/bjc.2017.354] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 07/31/2017] [Accepted: 09/07/2017] [Indexed: 12/26/2022] Open
Abstract
Background: Leiomyosarcoma (LMS) are 15% of adult sarcomas and remain seldom curable in metastatic phase. The TAM receptors and their ligands are overexpressed or activated in multiple malignancies, including LMS. Methods: The TAM receptor and ligand expression was evaluated in LMS cell lines and 358 sarcoma samples by either gene expression or immunohistochemistry. TYRO3 and AXL were knocked down. Crizotinib and foretinib were investigated in vitro. Results: High expression of TYRO3 and AXL was detected in LMS cell lines. TYRO3 or AXL gene knockdown reduced cell proliferation/colony formation. Crizotinib and foretinib decreased TYRO3 and AXL phosphorylation, apoptosis, G2/arrest and reduced colony formation. Immunohistochemistry performed in 107 sarcomas showed higher expression of TYRO3 and GAS6 in LMS vs other sarcomas and nuclear TYRO3 only in LMS. Microarray gene expression performed in 251 sarcomas revealed significantly higher expression of TYRO3 and GAS6 in LMS than other sarcomas. Leiomyosarcoma patients with high expression of GAS6 or PROS1 present a significantly worse PFS. Conclusions: Leiomyosarcoma patients, especially those whom develop metastasis, express higher levels of TYRO3 and GAS6. Crizotinib and foretinib showed effective antitumour activity in LMS through TYRO3 and AXL deactivation indicating that clinical trials using TYRO3 and AXL inhibitors are warranted in advanced LMS.
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Belfiore A, Malaguarnera R, Vella V, Lawrence MC, Sciacca L, Frasca F, Morrione A, Vigneri R. Insulin Receptor Isoforms in Physiology and Disease: An Updated View. Endocr Rev 2017; 38:379-431. [PMID: 28973479 PMCID: PMC5629070 DOI: 10.1210/er.2017-00073] [Citation(s) in RCA: 234] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 06/13/2017] [Indexed: 02/08/2023]
Abstract
The insulin receptor (IR) gene undergoes differential splicing that generates two IR isoforms, IR-A and IR-B. The physiological roles of IR isoforms are incompletely understood and appear to be determined by their different binding affinities for insulin-like growth factors (IGFs), particularly for IGF-2. Predominant roles of IR-A in prenatal growth and development and of IR-B in metabolic regulation are well established. However, emerging evidence indicates that the differential expression of IR isoforms may also help explain the diversification of insulin and IGF signaling and actions in various organs and tissues by involving not only different ligand-binding affinities but also different membrane partitioning and trafficking and possibly different abilities to interact with a variety of molecular partners. Of note, dysregulation of the IR-A/IR-B ratio is associated with insulin resistance, aging, and increased proliferative activity of normal and neoplastic tissues and appears to sustain detrimental effects. This review discusses novel information that has generated remarkable progress in our understanding of the physiology of IR isoforms and their role in disease. We also focus on novel IR ligands and modulators that should now be considered as an important strategy for better and safer treatment of diabetes and cancer and possibly other IR-related diseases.
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Affiliation(s)
- Antonino Belfiore
- Endocrinology, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy
| | - Roberta Malaguarnera
- Endocrinology, Department of Health Sciences, University Magna Graecia of Catanzaro, 88100 Catanzaro, Italy
| | - Veronica Vella
- School of Human and Social Sciences, University Kore of Enna, via della Cooperazione, 94100 Enna, Italy
| | - Michael C. Lawrence
- Structural Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
- Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Laura Sciacca
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, 95122 Catania, Italy
| | - Francesco Frasca
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, 95122 Catania, Italy
| | - Andrea Morrione
- Department of Urology and Biology of Prostate Cancer Program, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Riccardo Vigneri
- Endocrinology, Department of Clinical and Experimental Medicine, University of Catania, Garibaldi-Nesima Hospital, 95122 Catania, Italy
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Brand TM, Iida M, Corrigan KL, Braverman CM, Coan JP, Flanigan BG, Stein AP, Salgia R, Rolff J, Kimple RJ, Wheeler DL. RETRACTED: The receptor tyrosine kinase AXL mediates nuclear translocation of the epidermal growth factor receptor. Sci Signal 2017; 10:10/460/eaag1064. [PMID: 28049763 PMCID: PMC7094775 DOI: 10.1126/scisignal.aag1064] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The epidermal growth factor receptor (EGFR) is a therapeutic target in patients with various cancers. Unfortunately, resistance to EGFR-targeted therapeutics is common. Previous studies identified two mechanisms of resistance to the EGFR monoclonal antibody cetuximab. Nuclear translocation of EGFR bypasses the inhibitory effects of cetuximab, and the receptor tyrosine kinase AXL mediates cetuximab resistance by maintaining EGFR activation and downstream signaling. Thus, we hypothesized that AXL mediated the nuclear translocation of EGFR in the setting of cetuximab resistance. Cetuximab-resistant clones of non-small cell lung cancer in culture and patient-derived xenografts in mice had increased abundance of AXL and nuclear EGFR (nEGFR). Cellular fractionation analysis, super-resolution microscopy, and electron microscopy revealed that genetic loss of AXL reduced the accumulation of nEGFR. SRC family kinases (SFKs) and HER family ligands promote the nuclear translocation of EGFR. We found that AXL knockdown reduced the expression of the genes encoding the SFK family members YES and LYN and the ligand neuregulin-1 (NRG1). AXL knockdown also decreased the interaction between EGFR and the related receptor HER3 and accumulation of HER3 in the nucleus. Overexpression of LYN and NRG1 in cells depleted of AXL resulted in accumulation of nEGFR, rescuing the deficit induced by lack of AXL. Collectively, these data uncover a previously unrecognized role for AXL in regulating the nuclear translocation of EGFR and suggest that AXL-mediated SFK and NRG1 expression promote this process.
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Affiliation(s)
- Toni M. Brand
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave, Madison, Wisconsin, 53705 USA
| | - Mari Iida
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave, Madison, Wisconsin, 53705 USA
| | - Kelsey L. Corrigan
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave, Madison, Wisconsin, 53705 USA
| | - Cara M. Braverman
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave, Madison, Wisconsin, 53705 USA
| | - John P. Coan
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave, Madison, Wisconsin, 53705 USA
| | - Bailey G. Flanigan
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave, Madison, Wisconsin, 53705 USA
| | - Andrew P. Stein
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave, Madison, Wisconsin, 53705 USA
| | - Ravi Salgia
- Department of Medical Oncology & Therapeutics Research. City of Hope Comprehensive Cancer Center. 1500 East Duarte Road, Duarte, CA, 91010
| | - Jana Rolff
- Experimental Pharmacology and Oncology Berlin-Buch GmbH, Robert-Roessle-Str. 10, 13125 Berlin, Germany
| | - Randall J. Kimple
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave, Madison, Wisconsin, 53705 USA
| | - Deric L. Wheeler
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, 1111 Highland Ave, Madison, Wisconsin, 53705 USA,Corresponding author.
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17
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Björner S, Rosendahl AH, Simonsson M, Markkula A, Jirström K, Borgquist S, Rose C, Ingvar C, Jernström H. Body Mass Index Influences the Prognostic Impact of Combined Nuclear Insulin Receptor and Estrogen Receptor Expression in Primary Breast Cancer. Front Endocrinol (Lausanne) 2017; 8:332. [PMID: 29234306 PMCID: PMC5712344 DOI: 10.3389/fendo.2017.00332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 11/09/2017] [Indexed: 01/03/2023] Open
Abstract
The prognostic importance of tumor-specific nuclear insulin receptor (InsR) expression in breast cancer is unclear, while membrane and cytoplasmic localization of InsR is better characterized. The insulin signaling network is influenced by obesity and may interact with the estrogen receptor α (ERα) signaling. The purpose was to investigate the interplay between nuclear InsR, ER, body mass index (BMI), and prognosis. Tumor-specific expression of nuclear InsR was evaluated by immunohistochemistry in tissue microarrays from 900 patients with primary invasive breast cancer without preoperative treatment, included in a population-based cohort in Sweden (2002-2012) in relation to prognosis. Patients were followed for up to 11 years during which 107 recurrences were observed. Nuclear InsR+ expression was present in 214 patients (23.8%) and increased with longer time between surgery and staining (P < 0.001). There were significant effect modifications by ER status and BMI in relation to clinical outcomes. Nuclear InsR+ conferred higher recurrence-risk in patients with ER+ tumors, but lower risk in patients with ER- tumors (Pinteraction = 0.003). Normal-weight patients with nuclear InsR+ tumors had higher recurrence-risk, while overweight or obese patients had half the recurrence-risk compared to patients with nuclear InsR- tumors (Pinteraction = 0.007). Normal-weight patients with a nuclear InsR-/ER+ tumor had the lowest risk for recurrence compared to all other nuclear InsR/ER combinations [HRadj 0.50, 95% confidence interval (CI): 0.25-0.97], while overweight or obese patients with nuclear InsR-/ER- tumors had the worst prognosis (HRadj 7.75, 95% CI: 2.04-29.48). Nuclear InsR was more prognostic than ER among chemotherapy-treated patients. In summary, nuclear InsR may have prognostic impact among normal-weight patients with ER+ tumors and in overweight or obese patients with ER- tumors. Normal-weight patients with nuclear InsR-/ER+ tumors may benefit from less treatment than normal-weight patients with other nuclear InsR/ER combinations. Overweight or obese patients with nuclear InsR-/ER- tumors may benefit from more tailored treatment or weight management.
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Affiliation(s)
- Sofie Björner
- Faculty of Medicine, Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Lund, Sweden
| | - Ann H. Rosendahl
- Faculty of Medicine, Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Lund, Sweden
| | - Maria Simonsson
- Faculty of Medicine, Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Lund, Sweden
| | - Andrea Markkula
- Faculty of Medicine, Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Lund, Sweden
| | - Karin Jirström
- Faculty of Medicine, Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Lund, Sweden
| | - Signe Borgquist
- Faculty of Medicine, Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Lund, Sweden
- Clinical Trial Unit, Forum South, Skåne University Hospital, Lund, Sweden
| | - Carsten Rose
- CREATE Health and Department of Immunotechnology, Lund University, Lund, Sweden
| | - Christian Ingvar
- Department of Clinical Sciences Lund, Surgery, Lund University, Skåne University Hospital, Lund, Sweden
| | - Helena Jernström
- Faculty of Medicine, Department of Clinical Sciences Lund, Oncology and Pathology, Lund University, Lund, Sweden
- *Correspondence: Helena Jernström,
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18
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Insulin-related signaling pathways elicited by light in photoreceptor nuclei from bovine retina. Exp Eye Res 2016; 145:36-47. [DOI: 10.1016/j.exer.2015.10.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 10/27/2015] [Accepted: 10/28/2015] [Indexed: 11/22/2022]
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19
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Merlot AM, Sahni S, Lane DJR, Fordham AM, Pantarat N, Hibbs DE, Richardson V, Doddareddy MR, Ong JA, Huang MLH, Richardson DR, Kalinowski DS. Potentiating the cellular targeting and anti-tumor activity of Dp44mT via binding to human serum albumin: two saturable mechanisms of Dp44mT uptake by cells. Oncotarget 2016; 6:10374-98. [PMID: 25848850 PMCID: PMC4496362 DOI: 10.18632/oncotarget.3606] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 02/14/2015] [Indexed: 12/31/2022] Open
Abstract
Di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT) demonstrates potent anti-cancer activity. We previously demonstrated that 14C-Dp44mT enters and targets cells through a carrier/receptor-mediated uptake process. Despite structural similarity, 2-benzoylpyridine 4-ethyl-3-thiosemicarbazone (Bp4eT) and pyridoxal isonicotinoyl hydrazone (PIH) enter cells via passive diffusion. Considering albumin alters the uptake of many drugs, we examined the effect of human serum albumin (HSA) on the cellular uptake of Dp44mT, Bp4eT and PIH. Chelator-HSA binding studies demonstrated the following order of relative affinity: Bp4eT≈PIH>Dp44mT. Interestingly, HSA decreased Bp4eT and PIH uptake, potentially due to its high affinity for the ligands. In contrast, HSA markedly stimulated Dp44mT uptake by cells, with two saturable uptake mechanisms identified. The first mechanism saturated at 5-10 μM (Bmax:1.20±0.04 × 107 molecules/cell; Kd:33±3 μM) and was consistent with a previously identified Dp44mT receptor/carrier. The second mechanism was of lower affinity, but higher capacity (Bmax:2.90±0.12 × 107 molecules/cell; Kd:65±6 μM), becoming saturated at 100 μM and was only evident in the presence of HSA. This second saturable Dp44mT uptake process was inhibited by excess HSA and had characteristics suggesting it was mediated by a specific binding site. Significantly, the HSA-mediated increase in the targeting of Dp44mT to cancer cells potentiated apoptosis and could be important for enhancing efficacy.
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Affiliation(s)
- Angelica M Merlot
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, NSW, Australia
| | - Sumit Sahni
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, NSW, Australia
| | - Darius J R Lane
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, NSW, Australia
| | - Ashleigh M Fordham
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, NSW, Australia
| | - Namfon Pantarat
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, NSW, Australia
| | - David E Hibbs
- Faculty of Pharmacy, The University of Sydney, Sydney, NSW, Australia
| | - Vera Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, NSW, Australia
| | | | - Jennifer A Ong
- Faculty of Pharmacy, The University of Sydney, Sydney, NSW, Australia
| | - Michael L H Huang
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, NSW, Australia
| | - Des R Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, NSW, Australia
| | - Danuta S Kalinowski
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, The University of Sydney, Sydney, NSW, Australia
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20
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Sarfstein R, Werner H. Minireview: nuclear insulin and insulin-like growth factor-1 receptors: a novel paradigm in signal transduction. Endocrinology 2013; 154:1672-9. [PMID: 23507573 DOI: 10.1210/en.2012-2165] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The specificity of the insulin receptor (InsR) and insulin-like growth factor-1 receptor (IGF1R) signaling pathways has been the focus of significant debate over the past few years. Recent evidence showing nuclear import and a direct transcriptional role for both InsR and IGF1R adds a new layer of complexity to this dialog. Hence, in addition to the classical roles associated with cell-surface receptors (eg, ligand binding, autophosphorylation of the tyrosine kinase domain, activation of insulin receptor substrate 1 (IRS-1) and additional substrates, protein-protein interactions with membrane and cytoplasm components), new data are consistent with nuclear (genomic) role(s) for both InsR and IGF1R. The present review provides a brief overview of the physical and functional similarities and differences between InsR and IGF1R and describes data from a number of laboratories providing evidence for a new layer of signaling regulation (ie, the ability of InsR and IGF1R to translocate to the cell nucleus and to elicit genomic activities usually associated with transcription factors). The ability of InsR and IGF1R to function as transcription factors, although poorly understood, constitutes a new paradigm in signal transduction. Although research on the role of nuclear InsR/IGF1R is still in its infancy, we believe that this rapidly developing area may have a major basic and translational impact on the fields of metabolism, diabetes, and cancer.
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Affiliation(s)
- Rive Sarfstein
- PhD, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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21
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Abstract
Insulin analogues have been developed in an attempt to achieve a more physiological replacement of insulin and thereby a better glycaemic control. However, structural modification of the insulin molecule may result in altered binding affinities and activities to the IGF1 receptor (IGF1R). As a consequence, insulin analogues may theoretically have an increased mitogenic action compared to human insulin. In view of the lifelong exposure and large patient populations involved, insulin analogues with an increased mitogenic effect in comparison to human insulin may potentially constitute a major health problem, since these analogues may possibly induce the growth of pre-existing neoplasms. This hypothesis has been evaluated extensively in vitro and also in vivo by using animal models. In vitro, all at present commercially available insulin analogues have lower affinities for the insulin receptor (IR). Although it has been suggested that especially insulin analogues with an increased affinity for the IGF1R (such as insulin glargine) are more mitogenic when tested in vitro in cells expressing a high proportion of IGF1R, the question remains whether this has any clinical consequences. At present, there are several uncertainties which make it very difficult to answer this question decisively. In addition, recent data suggest that insulin (or insulin analogues)-mediated stimulation of IRs may play a key role in the progression of human cancer. More detailed information is required to elucidate the exact mechanisms as to how insulin analogues may activate the IR and IGF1R and how this activation may be linked to mitogenesis.
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Affiliation(s)
- Aimee J Varewijck
- Division of Endocrinology, Department of Internal Medicine, Erasmus Medical Center, CE Rotterdam, The Netherlands
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22
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Singh B, Xu Y, McLaughlin T, Singh V, Martinez JA, Krishnan A, Zochodne DW. Resistance to trophic neurite outgrowth of sensory neurons exposed to insulin. J Neurochem 2012; 121:263-76. [DOI: 10.1111/j.1471-4159.2012.07681.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Mayer P, Reitzenstein U, Warnken M, Enzmann H, Racké K. Insulin action on H292 bronchial carcinoma cells as compared to normal bronchial epithelial cells. Pulm Pharmacol Ther 2011; 25:104-14. [PMID: 22210006 DOI: 10.1016/j.pupt.2011.12.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2010] [Revised: 11/14/2011] [Accepted: 12/18/2011] [Indexed: 12/14/2022]
Abstract
Inhaled insulin may contribute to bronchial carcinoma due to IGF-I receptor activation by high local concentrations. Therefore, effects of insulin and IGF-I on human bronchial carcinoma cells (H292) and normal bronchial epithelium cells (HBE) were studied. TGF-β was included since it also influences carcinoma progression. H292 and HBE cells expressed both the insulin receptor and the IGF-I receptor; in H292 cells an additional, shorter, splicing variant (IR-A) of the insulin receptor was present. Insulin receptor expression was around four to five times higher in H292 than in HBE cells at mRNA and protein levels. Insulin and TGF-β exerted contrary actions on proliferation and gene expression in H292 cells. Genes regulated by insulin, IGF-I, and TGF-β were linked to inflammation, cell adhesion, muscle contraction and differentiation. Insulin and IGF-I also suppressed DNA repair genes. EC(50) for insulin-induced proliferation was around 5 nM in H292 and around 30 nM HBE cells. The EC(50) values for gene expression ranged from 9 to 90 nM in both cell types, dependent on the gene studied. In H292 cells, the proliferative response was much stronger if TGF-β was present. In HBE cells this interaction of insulin and TGF-β was not observed, and changes in gene expression were mostly lower by at least 10-fold as compared to H292. All in all, the insulin effects in H292 were generally much stronger than in HBE cells and - with regard to proliferation - occurred at lower concentrations. Thus, insulin will hardly induce cancer from normal bronchial cells but may favour progression of pre-existing tumours.
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Affiliation(s)
- Peter Mayer
- Federal Institute for Drugs and Medical Devices (BfArM), Kurt-Georg-Kiesinger-Allee 3, D-53175 Bonn, Germany.
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Zouein FA, Duhé RJ, Booz GW. JAKs go nuclear: emerging role of nuclear JAK1 and JAK2 in gene expression and cell growth. Growth Factors 2011; 29:245-52. [PMID: 21892841 PMCID: PMC3595105 DOI: 10.3109/08977194.2011.614949] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The four Janus kinases (JAKs) comprise a family of intracellular, nonreceptor tyrosine kinases that first gained attention as signaling mediators of the type I and type II cytokine receptors. Subsequently, the JAKs were found to be involved in signaling downstream of the insulin receptor, a number of receptor tyrosine kinases, and certain G-protein coupled receptors. Although a number of cytoplasmic targets for the JAKs have been identified, their predominant action was found to be the phosphorylation and activation of the signal transducers and activators of transcription (STAT) factors. Through the STATs, the JAKs activate gene expression linked to cellular stress, proliferation, and differentiation. The JAKs are especially important in hematopoiesis, inflammation, and immunity, and aberrant JAK activity has been implicated in a number of disorders including rheumatoid arthritis, psoriasis, polycythemia vera, and myeloproliferative diseases. Although once thought to reside strictly in the cytoplasm, recent evidence shows that JAK1 and JAK2 are present in the nucleus of certain cells often under conditions associated with high rates of cell growth. Nuclear JAKs have now been shown to affect gene expression by activating other transcription factors besides the STATs and exerting epigenetic actions, for example, by phosphorylating histone H3. The latter action derepresses global gene expression and has been implicated in leukemogenesis. Nuclear JAKs may have a role as well in stem cell biology. Here we describe recent developments in understanding the noncanonical nuclear actions of JAK1 and JAK2.
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Affiliation(s)
- Fouad A. Zouein
- Department of Pharmacology and Toxicology, School of Medicine, The University of Mississippi Medical Center, Jackson, Mississippi, USA
- The Center for Excellence in Cardiovascular-Renal Research, The University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Roy J. Duhé
- Department of Pharmacology and Toxicology, School of Medicine, The University of Mississippi Medical Center, Jackson, Mississippi, USA
- University of Mississippi Cancer Institute, The University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - George W. Booz
- Department of Pharmacology and Toxicology, School of Medicine, The University of Mississippi Medical Center, Jackson, Mississippi, USA
- The Center for Excellence in Cardiovascular-Renal Research, The University of Mississippi Medical Center, Jackson, Mississippi, USA
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25
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Mikula M, Bomsztyk K. Direct recruitment of ERK cascade components to inducible genes is regulated by heterogeneous nuclear ribonucleoprotein (hnRNP) K. J Biol Chem 2011; 286:9763-75. [PMID: 21233203 DOI: 10.1074/jbc.m110.213330] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Components of the ERK cascade are recruited to genes, but it remains unknown how they are regulated at these sites. The RNA-binding protein heterogeneous nuclear ribonucleoprotein (hnRNP) K interacts with kinases and is found along genes including the mitogen-inducible early response gene EGR-1. Here, we used chromatin immunoprecipitations to study co-recruitment of hnRNP K and ERK cascade activity along the EGR-1 gene. These measurements revealed that the spatiotemporal binding patterns of ERK cascade transducers (GRB2, SOS, B-Raf, MEK, and ERK) at the EGR-1 locus resemble both hnRNP K and RNA polymerase II (Pol II). Inhibition of EGR-1 transcription with either serum-responsive factor knockdown or 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole altered recruitment of all of the above ERK cascade components along this locus that mirrored the changes in Pol II and hnRNP K profiles. siRNA knockdown of hnRNP K decreased the levels of active MEK and ERK at the EGR-1, changes associated with decreased levels of elongating pre-mRNA and less efficient splicing. The hnRNP K dependence and pattern of ERK cascade activation at the c-MYC locus were different from at EGR-1. Ribonucleoprotein immunoprecipitations revealed that hnRNP K was associated with the EGR-1 but not c-MYC mRNAs. These data suggest a model where Pol II transcription-driven recruitment of hnRNP K along the EGR-1 locus compartmentalizes activation of the ERK cascade at these genes, events that regulate synthesis of mature mRNA.
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Affiliation(s)
- Michal Mikula
- Department of Medicine, University of Washington, Seattle, Washington 98109, USA
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26
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Nelson JD, LeBoeuf RC, Bomsztyk K. Direct recruitment of insulin receptor and ERK signaling cascade to insulin-inducible gene loci. Diabetes 2011; 60:127-37. [PMID: 20929976 PMCID: PMC3012164 DOI: 10.2337/db09-1806] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
OBJECTIVE Insulin receptor (IR) translocates to the nucleus, but its recruitment to gene loci has not been demonstrated. Here, we tested the hypothesis that IR and its downstream mitogenic transducers are corecruited to two prototypic insulin-inducible genes: early growth response 1 (egr-1), involved in mitogenic response, and glucokinase (Gck), encoding a key metabolic enzyme. RESEARCH DESIGN AND METHODS We used RNA and chromatin from insulin-treated rat hepatic tumor cell line expressing human insulin receptor (HTC-IR) and livers from lean and insulin-resistant ob/ob glucose-fed mice in quantitative RT-PCR and chromatin immunoprecipitation studies to determine gene expression levels and associated recruitment of RNA polymerase II (Pol II), insulin receptor, and cognate signaling proteins to gene loci, respectively. RESULTS Insulin-induced egr-1 mRNA in HTC-IR cells was associated with corecruitment of IR signaling cascade (IR, SOS, Grb2, B-Raf, MEK, and ERK) to this gene. Recruitment profiles of phosphorylated IR, B-Raf, MEK, and Erk along egr-1 transcribed region were similar to those of elongating Pol II. Glucose-feeding increased Gck mRNA expression in livers of lean but not ob/ob mice. In lean mice, there was glucose feeding-induced recruitment of IR and its transducers to Gck gene synchronized with elongating Pol II. In sharp contrast, in glucose-fed ob/ob mice, the Gck recruitment patterns of active MEK/Erk, IR, and Pol II were asynchronous. CONCLUSIONS IR and its signal transducers recruited to genes coupled to elongating Pol II may play a role in maintaining productive mRNA synthesis of target genes. These studies suggest a possibility that impaired Pol II processivity along genes bearing aberrant levels of IR/signal transducers is a previously unrecognized facet of insulin resistance.
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Affiliation(s)
- Joel D. Nelson
- Molecular and Cellular Biology Program, University of Washington, Seattle, Washington
- UW Medicine Lake Union, University of Washington, Seattle, Washington
| | - Renée C. LeBoeuf
- UW Medicine Lake Union, University of Washington, Seattle, Washington
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, Washington
| | - Karol Bomsztyk
- Molecular and Cellular Biology Program, University of Washington, Seattle, Washington
- UW Medicine Lake Union, University of Washington, Seattle, Washington
- Corresponding author: Karol Bomsztyk,
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Rodrigues MA, Gomes DA, Andrade VA, Leite MF, Nathanson MH. Insulin induces calcium signals in the nucleus of rat hepatocytes. Hepatology 2008; 48:1621-31. [PMID: 18798337 PMCID: PMC2825885 DOI: 10.1002/hep.22424] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Insulin is an hepatic mitogen that promotes liver regeneration. Actions of insulin are mediated by the insulin receptor, which is a receptor tyrosine kinase. It is currently thought that signaling via the insulin receptor occurs at the plasma membrane, where it binds to insulin. Here we report that insulin induces calcium oscillations in isolated rat hepatocytes, and that these calcium signals depend upon activation of phospholipase C and the inositol 1,4,5-trisphosphate receptor, but not upon extracellular calcium. Furthermore, insulin-induced calcium signals occur in the nucleus, and are temporally associated with selective depletion of nuclear phosphatidylinositol bisphosphate and translocation of the insulin receptor to the nucleus. These findings suggest that the insulin receptor translocates to the nucleus to initiate nuclear, inositol 1,4,5-trisphosphate-mediated calcium signals in rat hepatocytes. This novel signaling mechanism may be responsible for insulin's effects on liver growth and regeneration.
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Affiliation(s)
- Michele A Rodrigues
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520-8019, USA
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Varma S, Khandelwal RL. Overexpression of Akt1 upregulates glycogen synthase activity and phosphorylation of mTOR in IRS-1 knockdown HepG2 cells. J Cell Biochem 2008; 103:1424-37. [PMID: 17721885 DOI: 10.1002/jcb.21525] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Insulin receptor substrate (IRS) proteins are important docking proteins in mediating the insulin signaling cascade. We have investigated the effect of short interfering RNA (siRNA) mediated knockdown of IRS-1 on insulin signaling cascade in primary human hepatocellular carcinoma HepG2 cell line and HepG2 cells overexpressing Akt1/PKB-alpha (HepG2-CA-Akt/PKB). IRS-1 knockdown in both cell lines resulted in reduction of insulin stimulated Akt1 phosphorylation at Ser 473. In parental HepG2 cells, IRS-1 knockdown resulted in reduction (ca. 50%) in the basal level of phosphorylated mTOR (Ser 2448) irrespective of insulin treatment. In contrast, HepG2-CA-Akt/PKB cells showed an upregulation in the basal level of phosphorylated mTOR (Ser 2448) (ca. 40%). Insulin mediated phosphorylation of mTOR was reduced. IRS-1 knockdown also reduced the cell proliferation of parental HepG2 cells by ca. 30% in the presence/absence of insulin, whereas in HepG2-CA-Akt/PKB the cell proliferation was reduced by 15% and treatment of insulin further reduced it to ca. 50% (vs. control). IRS-1 knockdown also reduced the glycogen synthase (GS) activity in parental HepG2 cells, however, it was upregulated in HepG2-CA-Akt/PKB cells. These results suggest that knockdown of IRS-1 abolished basal as well as insulin mediated phosphorylation/activity of proteins involved in cell proliferation or glycogen metabolism in the parental Hep2 cells. IRS-1 knockdown in cells overexpressing constitutively active Akt1/PKB-alpha either did not change or upregulated the basal levels of phosphorylated/active proteins. However, insulin mediated response was either not altered or downregulated in these cells.
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Affiliation(s)
- Shailly Varma
- Department of Biochemistry, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Canada S7N 5E5
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Béduneau A, Saulnier P, Benoit JP. Active targeting of brain tumors using nanocarriers. Biomaterials 2007; 28:4947-67. [PMID: 17716726 DOI: 10.1016/j.biomaterials.2007.06.011] [Citation(s) in RCA: 269] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Accepted: 06/06/2007] [Indexed: 02/06/2023]
Abstract
The delivery of drugs to brain tumors is limited by the presence of the blood-brain barrier (BBB) separating the blood from the cerebral parenchyma. An understanding of the specific mechanisms of the brain capillary endothelium has led to the development of various strategies to enhance the penetration of drugs into the brain tissue. Active targeting is a non-invasive approach, which consists in transporting drugs to target organs using site-specific ligands. Drug-loaded nanocarriers capable of recognizing brain capillary endothelial cells and cerebral tumoral cells have shown promising potential in oncology. Endogenous and chimeric ligands binding to carriers or receptors of the BBB have been directly or indirectly conjugated to nanocarriers. This review indexes the main targeted colloidal systems used for drug delivery to the brain. Their pharmacological behavior and their therapeutic effect are discussed.
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Lo HW, Hsu SC, Hung MC. EGFR signaling pathway in breast cancers: from traditional signal transduction to direct nuclear translocalization. Breast Cancer Res Treat 2006; 95:211-8. [PMID: 16261406 DOI: 10.1007/s10549-005-9011-0] [Citation(s) in RCA: 139] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aberrant epidermal growth factor receptor (EGFR) signaling is a major characteristic of many human malignancies including breast cancer. Since the discovery of EGF in 1960's and its receptor in 1980's, our understanding of the EGF/EGFR pathway has been significantly advanced and consequently, EGFR is considered as a major oncogenic factor and an attractive therapeutic target. The well-established traditional function of EGFR is known to transmit extra-cellular mitogenic signals, such as EGF and transforming growth factor-alpha (TGF-alpha), through activating a number of downstream signaling cascades. These include signaling modules that involve phospholipase C-gamma, Ras, and phosphatidylinositol-3 kinase (PI-3K). In cancer cells, the common outcomes following the activation of the EGFR-mediated downstream pathways are altered gene activities, leading to un-controlled tumor proliferation and apoptosis. Interestingly, emerging evidences suggest the existence of a direct mode of the EGFR pathway that is distinct from the traditional transduction pathway. This new mode of EGFR signaling involves cellular transport of EGFR from the cell-surface to the cell nucleus, association of nuclear EGFR complex with gene promoters, and transcriptional regulation of the target genes. Although the nature and pathological consequences of the nuclear EGFR pathway remain elusive, accumulating evidences suggest its association with increased tumor cell proliferation and poor survival rate in breast cancer patients. While several anti-EGFR agents are being tested in breast cancer patients clinically and others under pre-clinical development, a better understanding of the traditional and the nuclear EGFR pathways will facilitate the identification of patients that are likely to respond to these agents as well as future development of more effective anti-EGFR therapeutic interventions.
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Affiliation(s)
- Hui-Wen Lo
- Department of Molecular and Cellular Oncology, University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA
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31
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Wada-Hiraike O, Hiraike H, Okinaga H, Imamov O, Barros RPA, Morani A, Omoto Y, Warner M, Gustafsson JÅ. Role of estrogen receptor beta in uterine stroma and epithelium: Insights from estrogen receptor beta-/- mice. Proc Natl Acad Sci U S A 2006; 103:18350-5. [PMID: 17110437 PMCID: PMC1838754 DOI: 10.1073/pnas.0608861103] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
In this study, we compared the uterine tissue of estrogen receptor (ER)beta(-/-) mice and their WT littermates for differences in morphology, proliferation [the percentage of labeled cells 2 h after BrdUrd injection and EGF receptor (EGFR) expression], and differentiation (expression of progesterone receptor, E-cadherin, and cytokeratins). In ovariectomized mice, progesterone receptor expression in the uterine epithelium was similar in WT and ERbeta(-/-) mice, but E-cadherin and cytokeratin 18 expression was lower in ERbeta(-/-) mice. The percentage of cells in S phase was 1.5% in WT mice and 8% in ERbeta(-/-) mice. Sixteen hours after injection of 17beta-estradiol (E(2)), the number of BrdUrd-labeled cells increased 20-fold in WT mice and 80-fold in ERbeta(-/-) mice. Although ERalpha was abundant in intact mice, after ovariectomy, ERalpha could not be detected in the luminal epithelium of either WT or ERbeta(-/-) mice. In both untreated and E(2)-treated mice, ERalpha and ERbeta were colocalized in the nuclei of many stromal and glandular epithelial cells. However, upon E(2) + progesterone treatment, ERalpha and ERbeta were not coexpressed in any cells. In WT mice, EGFR was located on the membranes and in the cytoplasm of luminal epithelium, but not in the stroma. In ERbeta(-/-) mice, there was a marked expression of EGFR in the nuclei of epithelial and stromal cells. Upon E(2) treatment, EGFR on cell membranes was down-regulated in WT but not in ERbeta(-/-) mice. These findings reveal an important role for ERbeta in response to E(2) and in the organization, growth, and differentiation of the uterine epithelium.
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Affiliation(s)
- Osamu Wada-Hiraike
- *Department of Biosciences and Nutrition, Karolinska Institutet, S-141 86 Novum, Sweden; and
| | - Haruko Hiraike
- *Department of Biosciences and Nutrition, Karolinska Institutet, S-141 86 Novum, Sweden; and
| | - Hiroko Okinaga
- Department of Internal Medicine, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Otabek Imamov
- *Department of Biosciences and Nutrition, Karolinska Institutet, S-141 86 Novum, Sweden; and
| | - Rodrigo P. A. Barros
- *Department of Biosciences and Nutrition, Karolinska Institutet, S-141 86 Novum, Sweden; and
| | - Andrea Morani
- *Department of Biosciences and Nutrition, Karolinska Institutet, S-141 86 Novum, Sweden; and
| | - Yoko Omoto
- *Department of Biosciences and Nutrition, Karolinska Institutet, S-141 86 Novum, Sweden; and
| | - Margaret Warner
- *Department of Biosciences and Nutrition, Karolinska Institutet, S-141 86 Novum, Sweden; and
| | - Jan-Åke Gustafsson
- *Department of Biosciences and Nutrition, Karolinska Institutet, S-141 86 Novum, Sweden; and
- To whom correspondence should be addressed. E-mail:
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Lo HW, Ali-Seyed M, Wu Y, Bartholomeusz G, Hsu SC, Hung MC. Nuclear-cytoplasmic transport of EGFR involves receptor endocytosis, importin beta1 and CRM1. J Cell Biochem 2006; 98:1570-83. [PMID: 16552725 DOI: 10.1002/jcb.20876] [Citation(s) in RCA: 184] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Many receptor tyrosine kinases (RTKs) can be detected in the cell nucleus, such as EGFR, HER-2, HER-3, HER-4, and fibroblast growth factor receptor. EGFR, HER-2 and HER-4 contain transactivational activity and function as transcription co-factors to activate gene promoters. High EGFR in tumor nuclei correlates with increased tumor proliferation and poor survival in cancer patients. However, the mechanism by which cell-surface EGFR translocates into the cell nucleus remains largely unknown. Here, we found that EGFR co-localizes and interacts with importins alpha1/beta1, carriers that are critical for macromolecules nuclear import. EGFR variant mutated at the nuclear localization signal (NLS) is defective in associating with importins and in entering the nuclei indicating that EGFR's NLS is critical for EGFR/importins interaction and EGFR nuclear import. Moreover, disruption of receptor internalization process using chemicals and forced expression of dominant-negative Dynamin II mutant suppressed nuclear entry of EGFR. Additional evidences suggest an involvement of endosomal sorting machinery in EGFR nuclear translocalization. Finally, we found that nuclear export of EGFR may involve CRM1 exportin as we detected EGFR/CRM1 interaction and markedly increased nuclear EGFR following exposure to leptomycin B, a CRM1 inhibitor. Collectively, these data suggest the importance of receptor endocytosis, endosomal sorting machinery, interaction with importins alpha1/beta1, and exportin CRM1 in EGFR nuclear-cytoplasmic trafficking. Together, our work sheds light into the nature and regulation of the nuclear EGFR pathway and provides a plausible mechanism by which cells shuttle cell-surface EGFR and potentially other RTKs through the nuclear pore complex and into the nuclear compartment.
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Affiliation(s)
- Hui-Wen Lo
- Department of Molecular and Cellular Oncology, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd., Houston, Texas 77030, USA
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Lo HW, Hsu SC, Ali-Seyed M, Gunduz M, Xia W, Wei Y, Bartholomeusz G, Shih JY, Hung MC. Nuclear interaction of EGFR and STAT3 in the activation of the iNOS/NO pathway. Cancer Cell 2005; 7:575-89. [PMID: 15950906 DOI: 10.1016/j.ccr.2005.05.007] [Citation(s) in RCA: 391] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Revised: 03/08/2005] [Accepted: 05/09/2005] [Indexed: 10/25/2022]
Abstract
Epidermal growth factor receptor (EGFR) exists in the nucleus of highly proliferative cells where it functions as a transcription factor. Although EGFR has transactivational activity, it lacks a DNA binding domain and, therefore, may require a DNA binding transcription cofactor for its transcriptional function. Here, we report that EGFR physically interacts with signal transducers and activators of transcription 3 (STAT3) in the nucleus, leading to transcriptional activation of inducible nitric oxide synthase (iNOS). In breast carcinomas, nuclear EGFR positively correlates with iNOS. This study describes a mode of transcriptional control involving cooperated efforts of STAT3 and nuclear EGFR. Our work suggests that the deregulated iNOS/NO pathway may partly contribute to the malignant biology of tumor cells with high levels of nuclear EGFR and STAT3.
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Graidist P, Phongdara A, Fujise K. Antiapoptotic protein partners fortilin and MCL1 independently protect cells from 5-fluorouracil-induced cytotoxicity. J Biol Chem 2004; 279:40868-75. [PMID: 15262975 DOI: 10.1074/jbc.m401454200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fortilin, a potent 172-amino acid antiapoptotic polypeptide (Li, F., Zhang, D., and Fujise, K. (2001) J. Biol. Chem. 276, 47542-47549), binds MCL1, a protein of the antiapoptotic Bcl-2 family. The fortilin-MCL1 interaction stabilizes and increases the half-life of fortilin but not necessarily of MCL1 (Zhang, D., Li, F., Weidner, D., Mnjoyan, Z. H., and Fujise, K. (2002) J. Biol. Chem. 277, 37430-37438). It is not known to what extent each protein depends on the other for its apoptotic activity. Here, we present evidence that fortilin and MCL1 are capable of functioning as antiapoptotic proteins independently of each other. Using a robust small interfering RNA (siRNA)-mediated gene silencing system developed in our laboratory, we analyzed the cytoprotective effects of fortilin and MCL1 together and apart in U2OS cell lines exposed to 5-fluorouracil (5-FU) in both monoclonal and polyclonal cell populations. When MCL1 was silenced by MCL1-targeted siRNA, fortilin was still able to protect cells from 5-FU-induced cytotoxicity in a dose-dependent manner. Conversely, when fortilin was silenced by fortilin-targeted siRNA, MCL1 was also able to protect cells from 5-FU-induced cytotoxicity in a dose-dependent manner. Together, these data clearly suggest that fortilin and MCL1 can exert their cytoprotective activities independently of each other. The silencing of fortilin and MCL1 did not qualitatively change the subcellular localization of MCL1 and fortilin, respectively. The biological significance of fortilin-MCL1 interaction may be that it increases cellular resistance to apoptosis by allowing MCL1, an independently antiapoptotic protein, to stabilize another independently antiapoptotic protein, fortilin.
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Affiliation(s)
- Potchanapond Graidist
- Department of Biochemistry, Faculty of Science, Prince of Songkla University, Hat-Yai, Songkhla 90112, Thailand
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35
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Bernier M, He HJ, Kwon YK, Jang HJ. The roles of phospholipase C-gamma 1 and actin-binding protein filamin A in signal transduction of the insulin receptor. VITAMINS AND HORMONES 2004; 69:221-47. [PMID: 15196884 DOI: 10.1016/s0083-6729(04)69008-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Affiliation(s)
- Michel Bernier
- Diabetes Section, National Institute on Aging, National Institutes of Health, Baltimore, Maryland 21224, USA
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36
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Gupta D, Syed NA, Roesler WJ, Khandelwal RL. Effect of overexpression and nuclear translocation of constitutively active PKB-? on cellular survival and proliferation in HepG2 cells. J Cell Biochem 2004; 93:513-25. [PMID: 15372623 DOI: 10.1002/jcb.20200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Protein kinase B (Akt/PKB) is a key component in the PI 3-kinase mediated cell survival pathway and has oncogenic transformation potential. Although the over-expression of PKB-alpha can prevent cell death following growth factor withdrawal, the long-term effects of stable over-expression of PKB-alpha on cell survival in the absence of growth factors remain to be resolved. In the present study, we generated HepG2 cells with stable expression of active PKB-alpha and compared its characteristics with HepG2 cells. Basal as well as insulin-stimulated levels of Ser(473) and Thr(308) phosphorylation in PKB-alpha transfected HepG2 cells were much higher than HepG2 cells. Constitutive expression of active PKB-alpha enabled HepG2 cells to survive up to 96 h without serum in growth media while HepG2 cells fail to survive after 48 h of serum withdrawal. A strong positive correlation (R(2) = 0.71) between cell proliferation and phosphorylated form of PKB-alpha at Thr(308) was observed along with higher levels of phosphorylated 3'-phosphoinositide-dependent kinase-1 (PDK-1). HepG2 cells with constitutive expression of active PKB-alpha also showed higher levels of phosphorylated p65 subunit of nuclear factor-kappaB (NFkappaB) in comparison with HepG2 cells. Predominant nuclear localization of phosphorylated PKB-alpha was observed in stably transfected HepG2 cells. These results indicate that constitutive expression of active PKB-alpha renders HepG2 cells independent of serum based growth factors for survival and proliferation.
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Affiliation(s)
- Dhananjay Gupta
- Department of Biochemistry, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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37
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Polgar B, Kispal G, Lachmann M, Paar C, Nagy E, Csere P, Miko E, Szereday L, Varga P, Szekeres-Bartho J, Paar G. Molecular Cloning and Immunologic Characterization of a Novel cDNA Coding for Progesterone-Induced Blocking Factor. THE JOURNAL OF IMMUNOLOGY 2003; 171:5956-63. [PMID: 14634107 DOI: 10.4049/jimmunol.171.11.5956] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous studies from our laboratory showed that the immunomodulatory effects of progesterone are mediated by a 34-kDa protein, named the progesterone-induced blocking factor (PIBF). Lymphocytes of women with threatened abortion fail to produce this factor. Via inducing a Th2 biased cytokine production and blocking of NK activity, PIBF prevents induced pregnancy loss in mice, suggesting that substitution therapy with PIBF could be useful as an alternative treatment of certain forms of recurrent spontaneous abortions. Our study was aimed at mapping the sequence and structure of PIBF coding cDNA and characterizing the encoded protein product. Screening of a human liver cDNA library revealed a 2765-bp clone with a 2271-bp open reading frame. The PIBF1 cDNA encodes a protein of 757 amino acid residues with an 89-kDa predicted molecular mass, which shows no significant amino acid sequence homology with any known protein. PIBF produced via recombinant technique is recognized by the Ab specific for the secreted lymphocyte PIBF Ab, and possesses the biological activities of the secreted lymphocyte PIBF. The full-length PIBF is associated with the nucleus, whereas secretion of shorter forms, such a 34-kDa protein is induced by activation of the cell. The 48-kDa N-terminal part of PIBF is biologically active, and the part of the molecule, responsible for modulating NK activity is encoded by exons 2-4. These data provide an initial step for exploiting the possible diagnostic and therapeutic potential of this immunomodulatory molecule.
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MESH Headings
- Adjuvants, Immunologic/chemistry
- Adjuvants, Immunologic/genetics
- Adjuvants, Immunologic/isolation & purification
- Adjuvants, Immunologic/metabolism
- Amino Acid Sequence
- Antibody Specificity
- Cell Line, Tumor
- Cloning, Molecular/methods
- Cytokines/biosynthesis
- Cytotoxicity Tests, Immunologic
- DNA, Complementary/chemistry
- DNA, Complementary/immunology
- DNA, Complementary/isolation & purification
- Female
- Humans
- Immune Sera/metabolism
- Immunohistochemistry
- Intracellular Fluid/immunology
- Intracellular Fluid/metabolism
- K562 Cells
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Molecular Sequence Data
- Pregnancy
- Pregnancy Proteins/chemistry
- Pregnancy Proteins/genetics
- Pregnancy Proteins/immunology
- Pregnancy Proteins/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/immunology
- Recombinant Proteins/metabolism
- Recombinant Proteins/pharmacology
- Suppressor Factors, Immunologic/chemistry
- Suppressor Factors, Immunologic/genetics
- Suppressor Factors, Immunologic/immunology
- Suppressor Factors, Immunologic/metabolism
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Affiliation(s)
- Beata Polgar
- Department of Medical Microbiology and Immunology, Pecs University Medical School, Pecs, Hungary
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Lim MA, Kikani CK, Wick MJ, Dong LQ. Nuclear translocation of 3'-phosphoinositide-dependent protein kinase 1 (PDK-1): a potential regulatory mechanism for PDK-1 function. Proc Natl Acad Sci U S A 2003; 100:14006-11. [PMID: 14623982 PMCID: PMC283536 DOI: 10.1073/pnas.2335486100] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
3'-Phosphoinositide-dependent protein kinase 1 (PDK-1) phosphorylates and activates members of the AGC protein kinase family and plays an important role in the regulation of cell survival, differentiation, and proliferation. However, how PDK-1 is regulated in cells remains elusive. In this study, we demonstrated that PDK-1 can shuttle between the cytoplasm and nucleus. Treatment of cells with leptomycin B, a nuclear export inhibitor, results in a nuclear accumulation of PDK-1. PDK-1 nuclear localization is increased by insulin, and this process is inhibited by pretreatment of cells with phosphatidylinositol 3-kinase (PI3-kinase) inhibitors. Consistent with the idea that PDK-1 nuclear translocation is regulated by the PI3-kinase signaling pathway, PDK-1 nuclear localization is increased in cells deficient of PTEN (phosphatase and tensin homologue deleted on chromosome 10). Deletion mapping and mutagenesis studies unveiled that presence of a functional nuclear export signal (NES) in mouse PDK-1 located at amino acid residues 382 to 391. Overexpression of constitutively nuclear PDK-1, which retained autophosphorylation at Ser-244 in the activation loop in cells and its kinase activity in vitro, led to increased phosphorylation of the predominantly nuclear PDK-1 substrate p70 S6KbetaI. However, the ability of constitutively nuclear PDK-1 to induce anchorage-independent growth and to protect against UV-induced apoptosis is greatly diminished compared with the wild-type enzyme. Taken together, these findings suggest that nuclear translocation may be a mechanism to sequestrate PDK-1 from activation of the cytosolic signaling pathways and that this process may play an important role in regulating PDK-1-mediated cell signaling and function.
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Affiliation(s)
- Mei A Lim
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, TX 78229, USA
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Seol KC, Kim SJ. Nuclear matrix association of insulin receptor and IRS-1 by insulin in osteoblast-like UMR-106 cells. Biochem Biophys Res Commun 2003; 306:898-904. [PMID: 12821126 DOI: 10.1016/s0006-291x(03)01046-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the present study, we explored to determine whether insulin has any effect on the nuclear translocation of insulin receptor and IRS-1 in the nucleus of UMR-106 cells. Following insulin treatment, cells were subjected to subcellular fractionation. Each fraction containing equal amount of protein was subjected to Western blot analysis using antibodies against IR and IRS-1. Significant amounts of insulin receptors and IRS-1 were detected in the nucleus. Insulin receptor and IRS-1 appeared to be translocated to the nucleus in a time dependent manner by insulin whereas Akt levels remained unchanged by insulin treatment. The majority of insulin receptor and IRS-1 translocated to the nucleus appeared to associate with nuclear matrix. Tyrosine phosphorylation of a number of proteins with a molecular mass of 180, 95, 85, or 70 kDa in the nucleus was significantly stimulated by insulin, suggesting insulin signals to the nucleus and could regulate nuclear proteins. Confocal laser scanning microscope (CLSM) analysis also supports the nuclear translocation of insulin receptor and IRS-1. The nuclear insulin signaling may play an important role in the transcription control, differentiation, and growth of osteoblast cells.
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Affiliation(s)
- Ki-Cheon Seol
- Department of Pharmacology, School of Dentistry, Kyung Hee University, Seoul 130-701, Republic of Korea
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Zhang Y, Boado RJ, Pardridge WM. Marked enhancement in gene expression by targeting the human insulin receptor. J Gene Med 2003; 5:157-63. [PMID: 12539153 DOI: 10.1002/jgm.333] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Exogenous genes can be delivered to cells without viral vectors using an "artificial virus" comprised of nonviral plasmid DNA encapsulated in the interior of 85 nm pegylated immunoliposomes (PIL). The liposomes are targeted to cells with receptor-specific targeting ligands such as receptor-specific peptidomimetic monoclonal antibodies. METHODS The levels of luciferase gene expression in human or rat glioma cells are measured after targeting the PIL-encapsulated plasmid DNA via the human insulin receptor, the human epidermal growth factor receptor, or the rat transferrin receptor. The luciferase expression plasmids were either derived from pCEP4, which contains the Epstein-Barr nuclear antigen-1/oriP replication system, or from pGL2, which lacks this system for episomal replication of plasmid DNA. RESULTS Depending on the plasmid construct used and the receptor targeted, the peak luciferase gene expression varied more than 200-fold from 1.8 +/- 0.1 to 419 +/- 31 pg luciferase per mg cell protein. With the same plasmid, the peak level of gene expression following delivery to the cell via the human insulin receptor was 100-200-fold higher than gene expression following delivery via either the epidermal growth factor receptor or the transferrin receptor. There was no gene expression if the targeting ligand on the PIL was replaced with a nonspecific isotype control antibody. CONCLUSIONS The extent to which an exogenous gene is expressed within a cell via a nonviral, receptor-mediated gene transfer technology is determined by the receptor specificity of the targeting ligand. The highest levels of gene expression are obtained after targeting the insulin receptor, and this may derive from the nuclear targeting properties of this receptor system.
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Affiliation(s)
- Yun Zhang
- Department of Medicine, UCLA School of Medicine, Los Angeles, CA 90024, USA
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41
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Zhang Y, Zhu C, Pardridge WM. Antisense gene therapy of brain cancer with an artificial virus gene delivery system. Mol Ther 2002; 6:67-72. [PMID: 12095305 DOI: 10.1006/mthe.2002.0633] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Therapeutic genes are delivered to the nuclear compartment of cancer cells following intravenous administration with a non-immunogenic "artificial virus" gene delivery system that uses receptor-specific monoclonal antibodies (MAb) to navigate the biological barriers between the blood and the nucleus of the cancer cell. Mice implanted with intracranial U87 human glial brain tumors are treated with a nonviral expression plasmid encoding antisense mRNA against the human epidermal growth factor receptor gene (EGFR). The plasmid DNA is packaged within the interior of polyethylene glycol-modified (PEGylated) immunoliposomes, and delivered to the brain tumor with MAbs that target the mouse transferrin receptor (TRFR) and the human insulin receptor (INSR). The mouse TRFR MAb enables transport across the tumor vasculature, which is of mouse brain origin, and the INSR MAb causes transport across the plasma membrane and the nuclear membrane of the human brain cancer cell. The lifespan of the mice treated weekly with an intravenous administration of the EGFR antisense gene therapy packaged within the artificial virus is increased 100% relative to mice treated either with a luciferase gene or with saline.
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Affiliation(s)
- Yun Zhang
- Department of Medicine, UCLA School of Medicine, Los Angeles, California 90024, USA
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Marti U, Ruchti C, Kämpf J, Thomas GA, Williams ED, Peter HJ, Gerber H, Bürgi U. Nuclear localization of epidermal growth factor and epidermal growth factor receptors in human thyroid tissues. Thyroid 2001; 11:137-45. [PMID: 11288982 DOI: 10.1089/105072501300042785] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Epidermal growth factor (EGF) has widespread growth effects, and in some tissues proliferation is associated with the nuclear localization of EGF and epidermal growth factor receptor (EGFR). In the thyroid, EGF promotes growth but differs from thyrotropin (TSH) in inhibiting rather than stimulating functional parameters. We have therefore studied the occurrence and cellular distribution of EGF and EGFR in normal thyroid, in Graves' disease, where growth is mediated through the thyrotropin receptor (TSHR), and in a variety of human thyroid tumors. In the normal gland the staining was variable, but largely cytoplasmic, for both EGF and EGFR. In Graves' disease there was strong cytoplasmic staining for both EGF and EGFR, with frequent positive nuclei. Nuclear positivity for EGF and particularly for EGFR was also a feature of both follicular adenomas and follicular carcinomas. Interestingly, nuclear staining was almost absent in papillary carcinomas. These findings document for the first time the presence of nuclear EGF and EGFR in thyroid. Their predominant occurrence in tissues with increased growth (Graves' disease, follicular adenoma, and carcinoma) may indicate that nuclear EGF and EGFR play a role in growth regulation in these conditions. The absence of nuclear EGF and EGFR in papillary carcinomas would suggest that the role played by EGF in growth control differs between papillary carcinoma and follicular adenomas/carcinomas of the thyroid.
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Affiliation(s)
- U Marti
- Department of Clinical Chemistry, University Hospital, Bern, Switzerland.
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43
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The Regulation of Enzymatic Activity and Metabolism. Biochemistry 2001. [DOI: 10.1016/b978-012492543-4/50014-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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44
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Angermayr M, Strobel G, Müller G, Bandlow W. Stable plasma membrane expression of the soluble domain of the human insulin receptor in yeast. FEBS Lett 2000; 481:8-12. [PMID: 10984606 DOI: 10.1016/s0014-5793(00)01960-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The soluble cytoplasmic kinase domain of the human insulin receptor was N-terminally equipped with either an N-acetylation or a dual-acylation motif (MGC box, to allow myristoylation/palmitoylation) and expressed in yeast cells under the control of the inducible CUP1 promoter. Although the cellular concentration was about the same in both instances (reflecting similar stability against proteolysis), only the myristoylated protein was capable of autophosphorylation to a significant extent and was active to phosphorylate endogenous yeast proteins at tyrosine residues in vivo. Cellular subfractionation showed that the insulin receptor was associated with plasma membranes, from where it was not extractable with high salt or alkali, but a significant fraction was also localized in the nuclear fraction. The myristoylated protein is absent from the cytoplasm. No effect of expression of either the acetylated or the myristoylated version on growth and respiration on various carbon sources was detected, suggesting a failure of the active insulin receptor kinase domain to couple to yeast (glucose) signalling cascades.
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Affiliation(s)
- M Angermayr
- Institut für Genetik und Mikrobiologie, Maria-Ward-Strasse 1a, Munich, Germany
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45
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Fülöp AK, Hegyesi H. Non-Conventional Locations of Hormone Receptors (Binding Sites). A Review. ACTA BIOLOGICA HUNGARICA 1999. [DOI: 10.1007/bf03543057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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46
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Gletsu N, Dixon W, Clandinin MT. Insulin receptor at the mouse hepatocyte nucleus after a glucose meal induces dephosphorylation of a 30-kDa transcription factor and a concomitant increase in malic enzyme gene expression. J Nutr 1999; 129:2154-61. [PMID: 10573543 DOI: 10.1093/jn/129.12.2154] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Insulin receptor translocation to the nucleus may represent a mechanism for activation of transcription factors controlling lipogenic gene expression in the mouse hepatocyte. Insulin stimulation was achieved in vivo by oral glucose feeding of mice deprived of food for 24 h. Hepatocytes were fractionated after the glucose meal and nuclei were purified. Insulin receptor levels and phosphorylation state in nuclei were assessed by immunoassay. Insulin receptor significantly increased from basal levels in hepatocyte nuclei within 15 min of the glucose meal. Immunoassay using antiphosphotyrosine indicated that phosphorylation of nuclear insulin receptor increased, whereas phosphorylation of a 30-kDa DNA-binding protein significantly decreased within 15 min of the glucose meal. Glucose treatment significantly increased expression of malic enzyme within the time frame of insulin receptor translocation to the nucleus. Nuclear protein binding to an insulin response element (IRE) within the malic enzyme gene promoter significantly increased within 15 min of the glucose meal. When cell nuclei were isolated from mice that had been deprived of food and treated in vitro with purified, activated insulin receptor, changes were observed in DNA-binding protein phosphorylation and IRE-binding in the absence of cytoplasmic insulin signaling. In vitro incubation of nuclei with activated insulin receptor significantly decreased phosphorylation of a 30-kDa DNA-binding protein compared with basal levels. Increased binding of nuclear proteins to malic enzyme IRE was observed upon stimulation of isolated nuclei with activated insulin receptor. These results suggest that nuclear insulin receptors induce malic enzyme gene expression by regulating phosphorylation of IRE transcription factors.
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Affiliation(s)
- N Gletsu
- Nutrition and Metabolism Research Group, Department of Agricultural, Food and Nutritional Science, Department of Medicine, University of Alberta, Edmonton, AB, Canada T6G 2P5
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47
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Caplin ME, Clarke P, Grimes S, Dhillon AP, Khan K, Savage K, Lewin J, Michaeli D, Pounder RE, Watson SA. Demonstration of new sites of expression of the CCK-B/gastrin receptor in pancreatic acinar AR42J cells using immunoelectron microscopy. REGULATORY PEPTIDES 1999; 84:81-9. [PMID: 10535412 DOI: 10.1016/s0167-0115(99)00071-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The CCK-B/gastrin receptor has been characterised in both normal and tumour tissues. Endocytosis of the CCK-B/gastrin receptor has recently been demonstrated and this has similarly been described for other peptide receptors. In addition, ligand and ligand-receptor translocation to the nucleus has been demonstrated for other peptides. The aim of this study was to identify the sites of expression of the CCK-B/gastrin receptor in the known CCK-B/gastrin receptor bearing pancreatic acinar AR42J cells. The specificity of the CCK-B/gastrin receptor antibody (alpha-CCKBR-Ser antibody) was demonstrated by inhibition ELISA studies, radioligand inhibition studies and immunofluorescence binding studies on AR42J cells. Western blotting and immunogold electron microscopy techniques were used to identify the receptor in AR42J cell preparations. The affinity purified alpha-CCKBR-Ser antibody was shown to be specific for the CCK-B/gastrin receptor. The receptor was expressed on the cell membrane, in the cytoplasm and within the nucleus. Isoforms of the receptor protein identified in extra-nuclear and nuclear extracts ranged in molecular weight from 58 to 66 kDa. We conclude that the CCK-B/gastrin receptor is not only expressed on the cell membrane, but also in the cytoplasm and nucleus of AR42J pancreatic acinar cells.
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Affiliation(s)
- M E Caplin
- Department of Medicine and Histopathology, Royal Free Hospital School of Medicine, London, UK.
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48
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Misra UK, Gawdi G, Gonzalez-Gronow M, Pizzo SV. Coordinate regulation of the alpha(2)-macroglobulin signaling receptor and the low density lipoprotein receptor-related protein/alpha(2)-macroglobulin receptor by insulin. J Biol Chem 1999; 274:25785-91. [PMID: 10464317 DOI: 10.1074/jbc.274.36.25785] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have studied insulin-dependent regulation of macrophage alpha(2)-macroglobulin signaling receptors (alpha(2)MSR) and low density lipoprotein receptor-related protein/alpha(2)M receptors (LRP/alpha(2)MR) employing cell binding of (125)I-alpha(2)M*, inhibition of binding by receptor-associated protein (RAP) or Ni(2+), LRP/alpha(2)MR mRNA levels, and generation of second messengers. Insulin treatment increased the number of alpha(2)M* high (alpha(2)MSR) and low (LRP/alpha(2)MR) affinity binding sites from 1, 600 and 67,000 to 2,900 and 115,200 sites per cell, respectively. Neither RAP nor Ni(2+) blocked the binding of (125)I-alpha(2)M* to alpha(2)MSR on insulin- or buffer-treated cells, but they both blocked binding to LRP/alpha(2)MR. Insulin significantly increased LRP/alpha(2)MR mRNA levels in a dose- and time-dependent manner. Insulin-augmented (125)I-alpha(2)M* binding to macrophages was severely reduced by wortmannin, LY294002, PD98059, SB203580, or rapamycin. The increase in alpha(2)MSR receptor synthesis was reflected by augmented generation of IP(3) and increased [Ca(2+)](i) levels upon receptor ligation. Incubation of macrophages with wortmannin, LY294002, PD98059, SB203580, rapamycin, or antibodies against insulin receptors before insulin treatment and alpha(2)M* stimulation significantly reduced the insulin-augmented increase in IP(3) and [Ca(2+)](i) levels. Pretreatment of cells with actinomycin D or cycloheximide blocked the synthesis of new alpha(2)MSR. In conclusion, we show here that insulin coordinately regulates macrophage alpha(2)MSR and LRP/alpha(2)MR, utilizing both the PI 3-kinase and Ras signaling pathways to induce new synthesis of these receptors.
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Affiliation(s)
- U K Misra
- Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710, USA
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49
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Mertani HC, Morel G, Lobie PE. Cytoplasmic and nuclear cytokine receptor complexes. VITAMINS AND HORMONES 1999; 57:79-121. [PMID: 10232047 DOI: 10.1016/s0083-6729(08)60641-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Much of our understanding on how hormones and cytokines transmit their message into the cell is based on the receptor activation at the plasma membrane. Many experimental in vitro models have established the paradigm for cytokine action based upon such activation of their cell surface receptor. The signaling from the plasma membrane activated cytokine receptor is driven to the nucleus by a rapid ricochet of protein phosphorylation, ultimately integrated as a differentiative, proliferative, or transcriptional message. The Janus kinase (JAK)--signal transducers and activators of transcription (STAT) pathway that was first thought to be cytokine receptor specific now appears to be activated by other noncytokine receptors. Also, evidence is accumulating showing that cytokines modulate the signal transduction machinery of the tyrosine kinase receptors and that of the heterotrimeric guanosine triphosphate (GTP)-binding protein-coupled receptors. Thus cytokine receptor signaling has become much more complex than originally hypothesized, challenging the established model of specificity of the action of a given cytokine. This review is focused on another level of complexity emerging within cytokine receptor superfamily signaling. Over the past 10 years, data from different laboratories have shown that cytokines and their receptors localize to intracellular compartments including the nucleus, and, in some cases, biological responses have been correlated with this unexpected location, raising the possibility that cytokines act as their own messenger through inter-actions with nuclear proteins. Thus, the interplay between cytokine receptor engagement and cellular signaling turns out to be more dynamic than originally suspected. The mechanisms and regulations of intracellular translocation of the cytokines, their receptors, and their signaling proteins are discussed in the context that such compartmentalization provides some of the specificity of the responses mediated by each cytokine.
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Affiliation(s)
- H C Mertani
- Institute of Molecular and Cell Biology, Singapore, Republic of Singapore
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50
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Sperinde GV, Nugent MA. Heparan sulfate proteoglycans control intracellular processing of bFGF in vascular smooth muscle cells. Biochemistry 1998; 37:13153-64. [PMID: 9748322 DOI: 10.1021/bi980600z] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Basic fibroblast growth factor (bFGF) is a potent mitogen for vascular smooth muscle cells (VSMC) and has been implicated in a number of vascular disorders. bFGF interacts with high-affinity receptors and heparan sulfate proteoglycans (HSPG) at the cell surface. HSPG have been demonstrated to enhance bFGF binding to its receptors, yet no known role for HSPG in modulating postbinding events has been identified. In the present study, we analyzed bFGF internalization, intracellular distribution, degradation, and stimulation of DNA synthesis within native and HSPG-deficient VSMC. HSPG-deficient VSMC were generated by treating cells with sodium chlorate to inhibit the sulfation of HSPG. We found that stimulation of DNA synthesis by bFGF in chlorate-treated VSMC was markedly reduced as compared with native cells, even at doses of bFGF where receptor binding was similar in the two conditions. This was not a general lack of mitogenic potential, as the addition of calf serum, or epidermal growth factor, stimulated DNA synthesis to a similar extent in native and chlorate-treated cells. Analysis of the accumulation of internalized bFGF within cytoplasmic and nuclear fractions of native and HSPG-deficient VSMC showed striking differences. At early time points (0-2 h), nearly identical amounts of bFGF were observed in the cytoplasmic fractions under both conditions, yet significant amounts of bFGF were only found in the nuclear fractions of native cells. At later time points (2-48 h), the amount of cytoplasmic bFGF was significantly greater in the native compared to HSPG-deficient cells, and nuclear deposition of bFGF began to reach similar levels under both conditions. Furthermore, the intracellular half-life of bFGF was dramatically prolonged in native compared to HSPG-deficient cells, in part, due to decreased bFGF degradation in native cells. Thus, HSPG appears to accelerate nuclear localization, increase cytoplasmic capacity, and inhibit intracellular degradation of bFGF in VSMC. Modulation of intracellular processing of bFGF by HSPG might control the biological activity of bFGF in VSMC.
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MESH Headings
- 3T3 Cells
- Animals
- Cells, Cultured
- Chlorates/pharmacology
- DNA/antagonists & inhibitors
- DNA/biosynthesis
- DNA/drug effects
- Fibroblast Growth Factor 2/drug effects
- Fibroblast Growth Factor 2/metabolism
- Heparan Sulfate Proteoglycans/deficiency
- Heparan Sulfate Proteoglycans/physiology
- Humans
- Intracellular Fluid/drug effects
- Intracellular Fluid/metabolism
- Mice
- Mice, Inbred BALB C
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Protein Binding
- Protein Processing, Post-Translational/drug effects
- Receptors, Fibroblast Growth Factor/metabolism
- Temperature
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Affiliation(s)
- G V Sperinde
- Department of Biochemistry, Boston University School of Medicine, Massachusetts 02118, USA
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