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van den Akker GGH, Zacchini F, Housmans BAC, van der Vloet L, Caron MMJ, Montanaro L, Welting TJM. Current Practice in Bicistronic IRES Reporter Use: A Systematic Review. Int J Mol Sci 2021; 22:5193. [PMID: 34068921 PMCID: PMC8156625 DOI: 10.3390/ijms22105193] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/05/2021] [Accepted: 05/12/2021] [Indexed: 12/26/2022] Open
Abstract
Bicistronic reporter assays have been instrumental for transgene expression, understanding of internal ribosomal entry site (IRES) translation, and identification of novel cap-independent translational elements (CITE). We observed a large methodological variability in the use of bicistronic reporter assays and data presentation or normalization procedures. Therefore, we systematically searched the literature for bicistronic IRES reporter studies and analyzed methodological details, data visualization, and normalization procedures. Two hundred fifty-seven publications were identified using our search strategy (published 1994-2020). Experimental studies on eukaryotic adherent cell systems and the cell-free translation assay were included for further analysis. We evaluated the following methodological details for 176 full text articles: the bicistronic reporter design, the cell line or type, transfection methods, and time point of analyses post-transfection. For the cell-free translation assay, we focused on methods of in vitro transcription, type of translation lysate, and incubation times and assay temperature. Data can be presented in multiple ways: raw data from individual cistrons, a ratio of the two, or fold changes thereof. In addition, many different control experiments have been suggested when studying IRES-mediated translation. In addition, many different normalization and control experiments have been suggested when studying IRES-mediated translation. Therefore, we also categorized and summarized their use. Our unbiased analyses provide a representative overview of bicistronic IRES reporter use. We identified parameters that were reported inconsistently or incompletely, which could hamper data reproduction and interpretation. On the basis of our analyses, we encourage adhering to a number of practices that should improve transparency of bicistronic reporter data presentation and improve methodological descriptions to facilitate data replication.
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Affiliation(s)
- Guus Gijsbertus Hubert van den Akker
- Department of Orthopedic Surgery, Maastricht University, Medical Center+, 6229 ER Maastricht, The Netherlands; (G.G.H.v.d.A.); (B.A.C.H.); (L.v.d.V.); (M.M.J.C.)
| | - Federico Zacchini
- Department of Experimental, Diagnostic and Specialty Medicine, Bologna University, I-40138 Bologna, Italy; (F.Z.); (L.M.)
- Centro di Ricerca Biomedica Applicata—CRBA, Bologna University, Policlinico di Sant’Orsola, I-40138 Bologna, Italy
| | - Bas Adrianus Catharina Housmans
- Department of Orthopedic Surgery, Maastricht University, Medical Center+, 6229 ER Maastricht, The Netherlands; (G.G.H.v.d.A.); (B.A.C.H.); (L.v.d.V.); (M.M.J.C.)
| | - Laura van der Vloet
- Department of Orthopedic Surgery, Maastricht University, Medical Center+, 6229 ER Maastricht, The Netherlands; (G.G.H.v.d.A.); (B.A.C.H.); (L.v.d.V.); (M.M.J.C.)
| | - Marjolein Maria Johanna Caron
- Department of Orthopedic Surgery, Maastricht University, Medical Center+, 6229 ER Maastricht, The Netherlands; (G.G.H.v.d.A.); (B.A.C.H.); (L.v.d.V.); (M.M.J.C.)
| | - Lorenzo Montanaro
- Department of Experimental, Diagnostic and Specialty Medicine, Bologna University, I-40138 Bologna, Italy; (F.Z.); (L.M.)
- Centro di Ricerca Biomedica Applicata—CRBA, Bologna University, Policlinico di Sant’Orsola, I-40138 Bologna, Italy
- Programma Dipartimentale in Medicina di Laboratorio, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Via Albertoni 15, I-40138 Bologna, Italy
| | - Tim Johannes Maria Welting
- Department of Orthopedic Surgery, Maastricht University, Medical Center+, 6229 ER Maastricht, The Netherlands; (G.G.H.v.d.A.); (B.A.C.H.); (L.v.d.V.); (M.M.J.C.)
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Zhang H, Zhang S, Zhang J, Liu D, Wei J, Fang W, Zhao W, Chen Y, Shang D. ZO-1 expression is suppressed by GM-CSF via miR-96/ERG in brain microvascular endothelial cells. J Cereb Blood Flow Metab 2018; 38:809-822. [PMID: 28430012 PMCID: PMC5987931 DOI: 10.1177/0271678x17702668] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The level of granulocyte-macrophage colony-stimulating factor (GM-CSF) increases in some disorders such as vascular dementia, Alzheimer's disease, and multiple sclerosis. We previously reported that in Alzheimer's disease patients, a high level of GM-CSF in the brain parenchyma downregulated expression of ZO-1, a blood-brain barrier tight junction protein, and facilitated the infiltration of peripheral monocytes across the blood-brain barrier. However, the molecular mechanism underlying regulation of ZO-1 expression by GM-CSF is unclear. Herein, we found that the erythroblast transformation-specific (ETS) transcription factor ERG cooperated with the proto-oncogene protein c-MYC in regulation of ZO-1 transcription in brain microvascular endothelial cells (BMECs). The ERG expression was suppressed by miR-96 which was increased by GM-CSF through the phosphoinositide-3 kinase (PI3K)/Akt pathway. Inhibition of miR-96 prevented ZO-1 down-regulation induced by GM-CSF both in vitro and in vivo. Our results revealed the mechanism of ZO-1 expression reduced by GM-CSF, and provided a potential target, miR-96, which could block ZO-1 down-regulation caused by GM-CSF in BMECs.
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Affiliation(s)
- Hu Zhang
- Department of Developmental Cell Biology, Cell Biology Division, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning Province, PR China
| | - Shuhong Zhang
- Department of Developmental Cell Biology, Cell Biology Division, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning Province, PR China
| | - Jilin Zhang
- Department of Developmental Cell Biology, Cell Biology Division, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning Province, PR China
| | - Dongxin Liu
- Department of Developmental Cell Biology, Cell Biology Division, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning Province, PR China
| | - Jiayi Wei
- Department of Developmental Cell Biology, Cell Biology Division, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning Province, PR China
| | - Wengang Fang
- Department of Developmental Cell Biology, Cell Biology Division, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning Province, PR China
| | - Weidong Zhao
- Department of Developmental Cell Biology, Cell Biology Division, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning Province, PR China
| | - Yuhua Chen
- Department of Developmental Cell Biology, Cell Biology Division, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning Province, PR China
| | - Deshu Shang
- Department of Developmental Cell Biology, Cell Biology Division, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, Liaoning Province, PR China
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Boothby M, Rickert RC. Metabolic Regulation of the Immune Humoral Response. Immunity 2017; 46:743-755. [PMID: 28514675 DOI: 10.1016/j.immuni.2017.04.009] [Citation(s) in RCA: 155] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/15/2017] [Accepted: 04/21/2017] [Indexed: 12/13/2022]
Abstract
Productive humoral responses require that naive B cells and their differentiated progeny move among distinct micro-environments. In this review, we discuss how studies are beginning to address the nature of these niches as well as the interplay between cellular signaling, metabolic programming, and adaptation to the locale. Recent work adds evidence to the expectation that B cells at distinct stages of development or functional subsets are influenced by the altered profiles of nutrients and metabolic by-products that distinguish these sites. Moreover, emerging findings reveal a cross-talk among the external milieu, signal transduction pathways, and transcription factors that direct B cell fate in the periphery.
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Affiliation(s)
- Mark Boothby
- Department of Pathology, Microbiology and Immunology, School of Medicine, Vanderbilt University, and Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Medicine, School of Medicine, Vanderbilt University, and Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Cancer Biology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
| | - Robert C Rickert
- Tumor Microenvironment and Cancer Immunology Program, Sanford Burnham Prebys Medical Discovery Institute (SBP), La Jolla, CA 92037, USA; NCI-designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
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Rübsamen D, Kunze MM, Buderus V, Brauß TF, Bajer MM, Brüne B, Schmid T. Inflammatory conditions induce IRES-dependent translation of cyp24a1. PLoS One 2014; 9:e85314. [PMID: 24416388 PMCID: PMC3885688 DOI: 10.1371/journal.pone.0085314] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 12/04/2013] [Indexed: 01/28/2023] Open
Abstract
Rapid alterations in protein expression are commonly regulated by adjusting translation. In addition to cap-dependent translation, which is e.g. induced by pro-proliferative signaling via the mammalian target of rapamycin (mTOR)-kinase, alternative modes of translation, such as internal ribosome entry site (IRES)-dependent translation, are often enhanced under stress conditions, even if cap-dependent translation is attenuated. Common stress stimuli comprise nutrient deprivation, hypoxia, but also inflammatory signals supplied by infiltrating immune cells. Yet, the impact of inflammatory microenvironments on translation in tumor cells still remains largely elusive. In the present study, we aimed at identifying translationally deregulated targets in tumor cells under inflammatory conditions. Using polysome profiling and microarray analysis, we identified cyp24a1 (1,25-dihydroxyvitamin D3 24-hydroxylase) to be translationally upregulated in breast tumor cells co-cultured with conditioned medium of activated monocyte-derived macrophages (CM). Using bicistronic reporter assays, we identified and validated an IRES within the 5′ untranslated region (5′UTR) of cyp24a1, which enhances translation of cyp24a1 upon CM treatment. Furthermore, IRES-dependent translation of cyp24a1 by CM was sensitive to phosphatidyl-inositol-3-kinase (PI3K) inhibition, while constitutive activation of Akt sufficed to induce its IRES activity. Our data provide evidence that cyp24a1 expression is translationally regulated via an IRES element, which is responsive to an inflammatory environment. Considering the negative feedback impact of cyp24a1 on the vitamin D responses, the identification of a novel, translational mechanism of cyp24a1 regulation might open new possibilities to overcome the current limitations of vitamin D as tumor therapeutic option.
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Affiliation(s)
- Daniela Rübsamen
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
| | - Michael M. Kunze
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
| | - Victoria Buderus
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
| | - Thilo F. Brauß
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
| | - Magdalena M. Bajer
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
| | - Bernhard Brüne
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
| | - Tobias Schmid
- Institute of Biochemistry I, Faculty of Medicine, Goethe-University Frankfurt, Frankfurt, Germany
- * E-mail:
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Ornelas IM, Silva TM, Fragel-Madeira L, Ventura ALM. Inhibition of PI3K/Akt pathway impairs G2/M transition of cell cycle in late developing progenitors of the avian embryo retina. PLoS One 2013; 8:e53517. [PMID: 23301080 PMCID: PMC3534656 DOI: 10.1371/journal.pone.0053517] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 11/29/2012] [Indexed: 01/30/2023] Open
Abstract
PI3K/Akt is an important pathway implicated in the proliferation and survival of cells in the CNS. Here we investigated the participation of the PI3K/Akt signal pathway in cell cycle of developing retinal progenitors. Immunofluorescence assays performed in cultures of chick embryo retinal cells and intact tissues revealed the presence of phosphorylated Akt and 4E-BP1 in cells with typical mitotic profiles. Blockade of PI3K activity with the chemical inhibitor LY 294002 (LY) in retinal explants blocked the progression of proliferating cells through G2/M transition, indicated by an expressive increase in the number of cells labeled for phosphorylated histone H3 in the ventricular margin of the retina. No significant level of cell death could be detected at this region. Retinal explants treated with LY for 24 h also showed a significant decrease in the expression of phospho-Akt, phospho-GSK-3 and the hyperphosphorylated form of 4E-BP1. Although no change in the expression of cyclin B1 was detected, a significant decrease in CDK1 expression was noticed after 24 h of LY treatment both in retinal explants and monolayer cultures. Our results suggest that PI3K/Akt is an active pathway during proliferation of retinal progenitors and its activity appears to be required for proper CDK1 expression levels and mitosis progression of these cells.
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Affiliation(s)
- Isis Moraes Ornelas
- Department of Neurobiology, Neuroscience Program, Institute of Biology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Thayane Martins Silva
- Department of Neurobiology, Neuroscience Program, Institute of Biology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Lucianne Fragel-Madeira
- Department of Neurobiology, Neuroscience Program, Institute of Biology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
| | - Ana Lucia Marques Ventura
- Department of Neurobiology, Neuroscience Program, Institute of Biology, Fluminense Federal University, Niterói, Rio de Janeiro, Brazil
- * E-mail:
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Van Der Kelen K, Beyaert R, Inzé D, De Veylder L. Translational control of eukaryotic gene expression. Crit Rev Biochem Mol Biol 2009; 44:143-68. [PMID: 19604130 DOI: 10.1080/10409230902882090] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Translational control mechanisms are, besides transcriptional control and mRNA stability, the most determining for final protein levels. A large number of accessory factors that assist the ribosome during initiation, elongation, and termination of translation are required for protein synthesis. Cap-dependent translational control occurs mainly during the initiation step, involving eukaryotic initiation factors (eIFs) and accessory proteins. Initiation is affected by various stimuli that influence the phosphorylation status of both eIF4E and eIF2 and through binding of 4E-binding proteins to eIF4E, which finally inhibits cap- dependent translation. Under conditions where cap-dependent translation is hampered, translation of transcripts containing an internal ribosome entry site can still be supported in a cap-independent manner. An interesting example of translational control is the switch between cap-independent and cap-dependent translation during the eukaryotic cell cycle. At the G1-to-S transition, translation occurs predominantly in a cap-dependent manner, while during the G2-to-M transition, cap-dependent translation is inhibited and transcripts are predominantly translated through a cap-independent mechanism.
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Abstract
c-MYC inhibits differentiation and regulates the process by which cells acquire biomass, cell growth. Down-regulation of c-MYC, reduced cell growth, and decreased activity of the PI3K/AKT/mTORC1 signal transduction pathway are features of the terminal differentiation of committed myeloid precursors to polymorphonuclear neutrophils. Since mTORC1 regulates growth, we hypothesized that pharmacological inhibition of mTORC1 by rapamycin may reverse the phenotypic effects of c-MYC. Here we show that granulocytes blocked in their ability to differentiate by enforced expression of c-MYC can be induced to differentiate by reducing exogenous c-MYC expression through rapamycin treatment. Rapamycin also reduced expression of endogenous c-MYC and resulted in enhanced retinoid-induced differentiation. Total cellular c-Myc mRNA and c-MYC protein stability were unchanged by rapamycin, however the amount of c-Myc mRNA associated with polysomes was reduced. Therefore rapamycin limited expression of c-MYC by inhibiting c-Myc mRNA translation. These findings suggest that mTORC1 could be targeted to promote terminal differentiation in myeloid malignancies characterized by dysregulated expression of c-MYC.
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Chen CH, Lu PJ, Chen YC, Fu SL, Wu KJ, Tsou AP, Lee YCG, Lin TCE, Hsu SL, Lin WJ, Huang CYF, Chou CK. FLJ10540-elicited cell transformation is through the activation of PI3-kinase/AKT pathway. Oncogene 2007; 26:4272-83. [PMID: 17237822 DOI: 10.1038/sj.onc.1210207] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A significant challenge in the post-genomic era is how to prioritize differentially expressed and uncharacterized novel genes found in hepatocellular carcinoma (HCC) microarray profiling. One such category is cell cycle regulated genes that have only evolved in higher organisms but not in lower eukaryotic cells. Characterization of these genes may reveal some novel human cancer-specific abnormalities. A novel transcript, FLJ10540 was identified. FLJ10540 is overexpressed in HCC as examined by quantitative reverse transcription-polymerase chain reaction and immunohistochemistry. The patients with higher FLJ10540 expression had a poor survival than those with lower FLJ10540 expression. Functional characterization indicates that FLJ10540 displays a number of characteristics associated with an oncogene, including anchorage-independent growth, enhanced cell growth at low serum levels and induction of tumorigenesis in nude mice. FLJ10540-elicited cell transformation is mediated by activation of the phosphatidylinositol 3'-kinase (PI3K)/AKT pathway. Moreover, FLJ10540 forms a complex with PI3K and can activate PI3K activity, which provides a mechanistic basis for FLJ10540-mediated oncogenesis. Together, using a combination of bioinformatics searches and empirical data, we have identified a novel oncogene, FLJ10540, which is conserved only in higher organisms. The finding raises the possibility that FLJ10540 is a potential new therapeutic target for HCC treatment. These findings may contribute to the development of new therapeutic strategies that are able to block the PI3K/AKT pathway in cancer cells.
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Affiliation(s)
- C-H Chen
- Division of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County, Taiwan
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Xiong Z, Liu E, Yan Y, Silver RT, Yang F, Chen IH, Chen Y, Verstovsek S, Wang H, Prchal J, Yang XF. An unconventional antigen translated by a novel internal ribosome entry site elicits antitumor humoral immune reactions. THE JOURNAL OF IMMUNOLOGY 2006; 177:4907-16. [PMID: 16982933 PMCID: PMC3902139 DOI: 10.4049/jimmunol.177.7.4907] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Self-tumor Ags that elicit antitumor immune responses in responses to IFN-alpha stimulation remain poorly defined. We screened a human testis cDNA library with sera from three polycythemia vera patients who responded to IFN-alpha and identified a novel Ag, MPD6. MPD6 belongs to the group of cryptic Ags without conventional genomic structure and is encoded by a cryptic open reading frame located in the 3'-untranslated region of myotrophin mRNA. MPD6 elicits IgG Ab responses in a subset of polycythemia vera patients, as well as patients with chronic myelogenous leukemia and prostate cancer, suggesting that it is broadly immunogenic. The expression of myotrophin-MPD6 transcripts was up-regulated in some tumor cells, but only slightly increased in K562 cells in response to IFN-alpha treatment. By using bicistronic reporter constructs, we showed that the translation of MPD6 was mediated by a novel internal ribosome entry site (IRES) upstream of the MPD6 reading frame. Furthermore, the MPD6-IRES-mediated translation, but not myotrophin-MPD6 transcription, was significantly up-regulated in response to IFN-alpha stimulation. These findings demonstrate that a novel IRES-mediated mechanism may be responsible for the translation of unconventional self-Ag MPD6 in responsive to IFN-alpha stimulation. The eliciting antitumor immune response against unconventional Ag MPD6 in patients with myeloproliferative diseases suggests MPD6 as a potential target of novel immunotherapy.
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MESH Headings
- Amino Acid Sequence
- Antigens, Neoplasm/chemistry
- Antigens, Neoplasm/physiology
- Antigens, Neoplasm/ultrastructure
- Blotting, Northern
- Blotting, Western
- Enzyme-Linked Immunosorbent Assay
- Gene Library
- Humans
- Intercellular Signaling Peptides and Proteins/genetics
- Intercellular Signaling Peptides and Proteins/immunology
- Interferon-gamma/immunology
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/immunology
- Male
- Molecular Sequence Data
- Polycythemia Vera/immunology
- Prostatic Neoplasms/immunology
- Protein Biosynthesis
- Protein Structure, Secondary
- RNA, Messenger/analysis
- Reverse Transcriptase Polymerase Chain Reaction
- Ribosomes/chemistry
- Ribosomes/genetics
- Ribosomes/ultrastructure
- Testis/physiology
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Affiliation(s)
- Zeyu Xiong
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Enli Liu
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030
| | - Yan Yan
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Richard T. Silver
- Department of Medicine, New York Presbyterian-Weill Cornell Medical Center, New York, NY 10021
| | - Fan Yang
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Irene H. Chen
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Yangyang Chen
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Srdan Verstovsek
- Department of Leukemia, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030
| | - Hong Wang
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
| | - Josef Prchal
- Department of Medicine, University of Utah School of Medicine, Salt Lake City, UT 84112
- Department of Medicine, Baylor College of Medicine, Houston, TX 77030
| | - Xiao-Feng Yang
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
- Address correspondence and reprint requests to Dr. Xiao-Feng Yang, Department of Pharmacology, Temple University School of Medicine, 3420 North Broad Street, Philadelphia, PA 19140.
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Papapetrou EP, Zoumbos NC, Athanassiadou A. Genetic modification of hematopoietic stem cells with nonviral systems: past progress and future prospects. Gene Ther 2006; 12 Suppl 1:S118-30. [PMID: 16231044 DOI: 10.1038/sj.gt.3302626] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Serious unwanted complications provoked by retroviral gene transfer into hematopoietic stem cells (HSCs) have recently raised the need for the development and assessment of alternative gene transfer vectors. Within this context, nonviral gene transfer systems are attracting increasing interest. Their main advantages include low cost, ease of handling and large-scale production, large packaging capacity and, most importantly, biosafety. While nonviral gene transfer into HSCs has been restricted in the past by poor transfection efficiency and transient maintenance, in recent years, biotechnological developments are converting nonviral transfer into a realistic approach for genetic modification of cells of hematopoietic origin. Herein we provide an overview of past accomplishments in the field of nonviral gene transfer into hematopoietic progenitor/stem cells and we point at future challenges. We argue that episomally maintained self-replicating vectors combined with physical methods of delivery show the greatest promise among nonviral gene transfer strategies for the treatment of disorders of the hematopoietic system.
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Affiliation(s)
- E P Papapetrou
- Department of Biology, Faculty of Medicine, University of Patras, Patras, Greece
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Chanprasert S, Geddis AE, Barroga C, Fox NE, Kaushansky K. Thrombopoietin (TPO) induces c-myc expression through a PI3K- and MAPK-dependent pathway that is not mediated by Akt, PKCzeta or mTOR in TPO-dependent cell lines and primary megakaryocytes. Cell Signal 2005; 18:1212-8. [PMID: 16380230 DOI: 10.1016/j.cellsig.2005.09.010] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Accepted: 09/28/2005] [Indexed: 01/30/2023]
Abstract
Thrombopoietin (TPO) and its receptor (c-Mpl) are the major regulators of megakaryocyte and platelet production and serve a critical and non-redundant role in hematopoietic stem cell (HSC) biology. TPO signals through the Jak-STAT, Ras-Raf-MAPK, and PI3K pathways, and promotes survival, proliferation, and polyploidization in megakaryocytes. The proto-oncogene c-myc also plays an important role in many of these same processes. In this work we studied the regulated expression of c-myc in megakaryocytic cell lines and primary cells by quantitative real-time RT-PCR. We found that TPO induced expression of c-myc in 1 h in both hematopoietic cell lines (UT-7 and BaF3/Mpl) and mature murine megakaryocytes. The TPO-induced expression of c-myc was blocked by a phosphatidylinositol 3-kinase (PI3K) inhibitor, suggesting that TPO stimulated c-myc expression through a PI3K-dependent pathway. Of interest, our study showed that overexpression of active Akt did not rescue the effect of PI3K blockade on c-myc expression, rather, enhanced it. In addition, inhibitors of protein kinase C (PKC)zeta and the target of rapamycin (mTOR) also failed to affect c-myc mRNA expression, while c-myc mRNA expression was reduced by inhibition of the mitogen activated protein kinase (MAPK) pathway. Therefore, we conclude that TPO stimulates c-myc expression in primary megakaryocytes through a PI3K- and MAPK-dependent pathway that is not mediated by Akt, PKCzeta or mTOR.
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Affiliation(s)
- Supantitra Chanprasert
- Department of Clinical Microscopy, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
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12
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Kozak M. A second look at cellular mRNA sequences said to function as internal ribosome entry sites. Nucleic Acids Res 2005; 33:6593-602. [PMID: 16314320 PMCID: PMC1298923 DOI: 10.1093/nar/gki958] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2005] [Accepted: 10/26/2005] [Indexed: 01/27/2023] Open
Abstract
This review takes a second look at a set of mRNAs that purportedly employ an alternative mechanism of initiation when cap-dependent translation is reduced during mitosis or stress conditions. A closer look is necessary because evidence cited in support of the internal initiation hypothesis is often flawed. When putative internal ribosome entry sequences (IRESs) are examined more carefully, they often turn out to harbor cryptic promoters or splice sites. This undermines the dicistronic assay, wherein IRES activity is measured by the ability to support translation of the 3' cistron. Most putative IRESs still have not been checked carefully to determine whether the dicistronic vector produces only the intended dicistronic mRNA. The widespread use of the pRF vector is a major problem because this vector, which has Renilla luciferase as the 5' cistron and firefly luciferase as the 3' cistron, has been found to generate spliced transcripts. RNA transfection assays could theoretically circumvent these problems, but most candidate IRESs score very weakly in that test. The practice of calling even very weak results 'positive' is one of the problems discussed herein. The extremely low efficiency of putative IRESs is inconsistent with their postulated biological roles.'
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Affiliation(s)
- Marilyn Kozak
- Department of Biochemistry, Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA.
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Haneline LS, White H, Yang FC, Chen S, Orschell C, Kapur R, Ingram DA. Genetic reduction of class IA PI-3 kinase activity alters fetal hematopoiesis and competitive repopulating ability of hematopoietic stem cells in vivo. Blood 2005; 107:1375-82. [PMID: 16239435 PMCID: PMC1895408 DOI: 10.1182/blood-2005-05-1985] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Class I(A) phosphatidylinositol-3 kinase (PI-3K) is a lipid kinase, which is activated in blood cells by hematopoietic growth factors. In vitro experiments using chemical inhibitors of PI-3K suggest that this kinase is potentially important for hematopoietic stem and progenitor cell (HSC/P) function, and recent studies identify PI-3K as a therapeutic target in treating different leukemias and lymphomas. However, the role of PI-3K in regulating fetal liver or adult hematopoiesis in vivo is unknown. Therefore, we examined PI-3K-deficient embryos generated by a targeted deletion of the p85alpha and p85beta regulatory subunits of PI-3K (p85alpha-/-p85beta+/-). The absolute frequency and number of hematopoietic progenitor cells were reduced in p85alpha-/- p85beta+/- fetal livers compared with wild-type (WT) controls. Further, p85alpha-/-p85beta+/- fetal liver hematopoietic stem cells (HSCs) had decreased multilineage repopulating ability in vivo compared with WT controls in competitive repopulation assays. Finally, purified p85alpha-/-p85beta+/- c-kit+ cells had a decrease in proliferation in response to kit ligand (kitL), a growth factor important for controlling HSC function in vivo. Collectively, these data identify PI-3K as an important regulator of HSC function and potential therapeutic target in treating leukemic stem cells.
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Affiliation(s)
- Laura S Haneline
- Indiana University School of Medicine, Herman B. Wells Center for Pediatric Research, Indianapolis, IN 46202, USA
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Meyer S, Fergusson WD, Oostra AB, Medhurst AL, Waisfisz Q, de Winter JP, Chen F, Carr TF, Clayton-Smith J, Clancy T, Green M, Barber L, Eden OB, Will AM, Joenje H, Taylor GM. A cross-linker-sensitive myeloid leukemia cell line from a 2-year-old boy with severe Fanconi anemia and biallelic FANCD1/BRCA2 mutations. Genes Chromosomes Cancer 2005; 42:404-15. [PMID: 15645491 DOI: 10.1002/gcc.20153] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Fanconi anemia (FA) is a rare autosomal recessive disorder characterized by congenital and developmental abnormalities, hypersensitivity to DNA cross-linking agents such as mitomycin C (MMC), and strong predisposition to acute myeloid leukemia (AML). In this article, we describe clinical and molecular findings in a boy with a severe FA phenotype who developed AML by the age of 2. Although he lacked a strong family history of cancer, he was subsequently shown to carry biallelic mutations in the FANCD1/BRCA2 gene. These included an IVS7 splice-site mutation, which is strongly associated with early AML in homozygous or compound heterozygous carrier status in FA-D1 patients. Myeloid leukemia cells from this patient have been maintained in culture for more than 1 year and have been designated as the SB1690CB cell line. Growth of SB1690CB is dependent on granulocyte macrophage colony stimulating factor or interleukin-3. This cell line has retained its MMC sensitivity and has undergone further spontaneous changes in the spectrum of cytogenetic aberrations compared with the primary leukemia. This is the second AML cell line derived from an FA-D1 patient and the first proof that malignant clones arising in FA patients can retain inherited MMC sensitivity. As FA-derived malignancies are normally not very responsive to treatment, this implies there are important mechanisms of acquiring correction of the cellular FA phenotype that would explain the poor chemoresponsiveness observed in FA-associated malignancies and might also play a role in the initiation and progression of cancer in the general population.
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Affiliation(s)
- Stefan Meyer
- Cancer-Immunogenetics Laboratory, University of Manchester, St. Mary's Hospital, Hathersage Road, Manchester M13 0JH, United Kingdom.
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