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Perusina Lanfranca M, van Loben Sels JM, Ly CY, Grams TR, Dhummakupt A, Bloom DC, Davido DJ. A 77 Amino Acid Region in the N-Terminal Half of the HSV-1 E3 Ubiquitin Ligase ICP0 Contributes to Counteracting an Established Type 1 Interferon Response. Microbiol Spectr 2022; 10:e0059322. [PMID: 35730940 PMCID: PMC9430112 DOI: 10.1128/spectrum.00593-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Accepted: 05/12/2022] [Indexed: 11/20/2022] Open
Abstract
Herpes simplex virus 1 (HSV-1) is a human pathogen capable of establishing lifelong latent infections that can reactivate under stress conditions. A viral immediate early protein that plays important roles in the HSV-1 lytic and latent infections is the viral E3 ubiquitin ligase, ICP0. ICP0 transactivates all temporal classes of HSV-1 genes and facilitates viral gene expression. ICP0 also impairs the antiviral effects of interferon (IFN)-β, a component of host innate defenses known to limit viral replication. To begin to understand how ICP0 allows HSV-1 to disarm the IFN-β response, we performed genetic analyses using a series of ICP0 truncation mutants in the absence and presence of IFN-β in cell culture. We observed that IFN-β pretreatment of cells significantly impaired the replication of the ICP0 truncation mutants, n212 and n312, which code for the first 211 and 311 amino acids of ICP0, respectively; this effect of IFN-β correlated with decreased HSV-1 early and late gene expression. This increased sensitivity to IFN-β was not as apparent with the ICP0 mutant, n389. Our mapping studies indicate that loss of 77 amino acids from residues 312 to 388 in the N-terminal half of ICP0 resulted in a virus that was significantly more sensitive to cells pre-exposed to IFN-β. This 77 amino acid region contains a phospho-SUMO-interacting motif or -SIM, which we propose participates in ICP0's ability to counteract the antiviral response established by IFN-β. IMPORTANCE Interferons (IFNs) are secreted cellular factors that are induced by viral infection and limit replication. HSV-1 is largely refractory to the antiviral effects of type 1 IFNs, which are synthesized shortly after viral infection, in part through the activities of the viral regulatory protein, ICP0. To understand how ICP0 impedes the antiviral effects of type 1 IFNs, we used a series of HSV-1 ICP0 mutants and examined their viral replication and gene expression levels in cells stimulated with IFN-β (a type 1 IFN). Our mapping data identifies a discrete 77 amino acid region in the N-terminal half of ICP0 that facilitates HSV-1 resistance to IFN-β. This region of ICP0 is modified by phosphorylation and binds to the posttranslational modification SUMO, suggesting that HSV, and potentially other viruses, may counteract type 1 IFN signaling by altering SUMO and/or SUMO modified cellular proteins.
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Affiliation(s)
| | | | - Cindy Y. Ly
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
| | - Tristan R. Grams
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Adit Dhummakupt
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - David C. Bloom
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, Gainesville, Florida, USA
| | - David J. Davido
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, USA
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2
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Danziger O, Shai B, Sabo Y, Bacharach E, Ehrlich M. Combined genetic and epigenetic interferences with interferon signaling expose prostate cancer cells to viral infection. Oncotarget 2018; 7:52115-52134. [PMID: 27366948 PMCID: PMC5239539 DOI: 10.18632/oncotarget.10313] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 05/13/2016] [Indexed: 12/27/2022] Open
Abstract
Interferons (IFNs) induce anti-viral programs, regulate immune responses, and exert anti-proliferative effects. To escape anti-tumorigenic effects of IFNs, malignant cells attenuate JAK/STAT signaling and expression of IFN stimulated genes (ISGs). Such attenuation may enhance the susceptibility of tumor cells to oncolytic virotherapy. Here we studied genetic and epigenetic mechanisms of interference with JAK/STAT signaling and their contribution to susceptibility of prostate cancer cells to viral infection. Bioinformatics analysis of gene-expression in cohorts of prostate cancer patients revealed genetic and epigenetic interference with the IFN program. To correlate lack of IFN signaling and susceptibility to viral infection and oncolysis; we employed LNCaP prostate cancer cells as cellular model, and the human metapneumovirus and the epizootic hemorrhagic disease virus as infectious agents. In LNCaP cells, JAK1 is silenced by bi-allelic inactivating mutations and epigenetic silencing, which also silences ISGs. Chemical inhibition of epigenetic silencing partially restored IFN-sensitivity, induced low levels of expression of selected ISGs and attenuated, but failed to block, viral infection and oncolysis. Since viral infection was not blocked by epigenetic modifiers, and these compounds may independently-induce anti-tumor effects, we propose that epigenetic modifiers and virotherapy are compatible in treatment of prostate tumors defective in JAK1 expression and IFN signaling.
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Affiliation(s)
- Oded Danziger
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ben Shai
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Yosef Sabo
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Eran Bacharach
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Marcelo Ehrlich
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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3
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Hare D, Collins S, Cuddington B, Mossman K. The Importance of Physiologically Relevant Cell Lines for Studying Virus-Host Interactions. Viruses 2016; 8:v8110297. [PMID: 27809273 PMCID: PMC5127011 DOI: 10.3390/v8110297] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 10/13/2016] [Accepted: 10/26/2016] [Indexed: 12/11/2022] Open
Abstract
Viruses interact intimately with the host cell at nearly every stage of replication, and the cell model that is chosen to study virus infection is critically important. Although primary cells reflect the phenotype of healthy cells in vivo better than cell lines, their limited lifespan makes experimental manipulation challenging. However, many tumor-derived and artificially immortalized cell lines have defects in induction of interferon-stimulated genes and other antiviral defenses. These defects can affect virus replication, especially when cells are infected at lower, more physiologically relevant, multiplicities of infection. Understanding the selective pressures and mechanisms underlying the loss of innate signaling pathways is helpful to choose immortalized cell lines without impaired antiviral defense. We describe the trials and tribulations we encountered while searching for an immortalized cell line with intact innate signaling, and how directed immortalization of primary cells avoids many of the pitfalls of spontaneous immortalization.
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Affiliation(s)
- David Hare
- Pathology and Molecular Medicine, McMaster University, 1280 Main Str. West, Hamilton, ON L8S 4L8, Canada.
| | - Susan Collins
- Pathology and Molecular Medicine, McMaster University, 1280 Main Str. West, Hamilton, ON L8S 4L8, Canada.
| | - Breanne Cuddington
- Pathology and Molecular Medicine, McMaster University, 1280 Main Str. West, Hamilton, ON L8S 4L8, Canada.
| | - Karen Mossman
- Pathology and Molecular Medicine, McMaster University, 1280 Main Str. West, Hamilton, ON L8S 4L8, Canada.
- Biochemistry and Biomedical Sciences, McMaster University, 1280 Main Str. West, Hamilton, ON L8S 4L8, Canada.
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Moolmuang B, Singhirunnusorn P, Ruchirawat M. Effects of 5-Aza-2'-Deoxycytidine, Bromodeoxyuridine, Interferons and Hydrogen Peroxide on Cellular Senescence in Cholangiocarcinoma Cells. Asian Pac J Cancer Prev 2016; 17:957-63. [DOI: 10.7314/apjcp.2016.17.3.957] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Purcell M, Kruger A, Tainsky MA. Gene expression profiling of replicative and induced senescence. Cell Cycle 2015; 13:3927-37. [PMID: 25483067 DOI: 10.4161/15384101.2014.973327] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Cellular senescence is a cell cycle arrest accompanied by high expression of cyclin dependent kinase inhibitors which counteract overactive growth signals, which serves as a tumor suppressive mechanism. Senescence can be a result of telomere shortening (natural or replicative senescence) or DNA damage resulting from exogenous stressors (induced senescence). Here, we performed gene expression profiling through RNA-seq of replicative senescence, adriamycin-induced senescence, H2O2-induced senescence, and 5-aza-2-deoxycytidine-induced senescence in order to profile the pathways controlling various types of senescence. Overall, the pathways common to all 4 types of senescence were related to inflammation and the innate immune system. It was also evident that 5-aza-induced senescence mirrors natural replicative senescence due to telomere shortening. We also examined the prevalence of senescence-associated secretory phenotype (SASP) factors in the RNA-seq data, showing that it is a common characteristic of all 4 types of senescence. In addition, we could discriminate changes in gene expression due to quiescence during cellular senescence from those that were specific to senescence.
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Key Words
- 5-aza, 5-aza-2′-deoxycytidine
- 5-aza-2’-deoxycytidine
- GGA, Genomatix Genome Analyzer
- H2O2, hydrogen peroxide
- IFN, interferon
- IPA, Ingenuity Pathway Analysis
- LFS, Li-Fraumeni Syndrome
- LLP, lowest passage
- LP, low passage
- Li Fraumeni Syndrome
- RNA-seq
- SPIA, Signaling Pathway Impact Analysis
- Senescence
- adria, adriamycin
- adriamycin
- aging
- hydrogen peroxide
- nat, natural
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Affiliation(s)
- Maggie Purcell
- a Cancer Biology Program ; Wayne State University School of Medicine
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6
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Choi M, Lee C. Immortalization of Primary Keratinocytes and Its Application to Skin Research. Biomol Ther (Seoul) 2015; 23:391-9. [PMID: 26336577 PMCID: PMC4556197 DOI: 10.4062/biomolther.2015.038] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 05/01/2015] [Accepted: 05/06/2015] [Indexed: 01/16/2023] Open
Abstract
As a major component of the epidermal tissue, a primary keratinocyte has served as an essential tool not only for the study of pathogenesis of skin-related diseases but also for the assessment of potential toxicities of various chemicals used in cosmetics. However, its short lifespan in ex vivo setting has been a great hurdle for many practical applications. Therefore, a number of immortalization attempts have been made with success to overcome this limitation. In order to understand the immortalization process of a primary keratinocyte, several key biological phenomena governing its lifespan will be reviewed first. Then, various immortalization methods for the establishment of stable keratinocyte cell lines will be explained. Finally, its application to a three-dimensional skin culture system will be described.
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Affiliation(s)
- Moonju Choi
- College of Pharmacy, Dongguk University-Seoul, Goyang 410-820, Republic of Korea
| | - Choongho Lee
- College of Pharmacy, Dongguk University-Seoul, Goyang 410-820, Republic of Korea
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Lee HJ, Choi JH, Jung J, Kim JK, Lee SS, Kim GJ. Changes in PTTG1 by human TERT gene expression modulate the self-renewal of placenta-derived mesenchymal stem cells. Cell Tissue Res 2014; 357:145-57. [PMID: 24816985 DOI: 10.1007/s00441-014-1874-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 03/13/2014] [Indexed: 01/01/2023]
Abstract
In addition to their differentiation potential, self-renewal capability is an important characteristic of stem cells. The limited self-renewal activity of mesenchymal stem cells is the greatest obstacle to the application of stem cell therapy in regenerative medicine. The human TERT gene enhances the self-renewal of MSCs, but the mechanism of self-renewal and the interactions among TERT-gene-related molecules remain unknown. The objectives of this study were to generate immortalized MSCs derived from MSCs isolated from placenta (naive) by human TERT gene transfection with the AMAXA gene delivery system, to compare their characteristics, and to investigate whether increased TERT expression affected the pituitary tumor transforming gene (PTTG1; also known as securin), which is involved in chromosome segregation during mitosis. TERT-immortalized cells (TERT+) with a prolonged life span displayed high PTTG1 expression. TERT+ cells also retained the stemness capacity and multipotency of naive cells and displayed high PTTG1 expression. However, down-regulation of PTTG1 by treatment with short interfering RNA induced cell senescence and decreased telomerase activity. Moreover, TERT bound to PTTG1 formed complexes with chaperones such as Ku70 and heat shock protein 90. Thus, placental MSCs immortalized by TERT gene transfection display differentiation potential and exhibit enhanced self-renewal through a balanced interaction of PTTG1 and chaperones. The interaction between TERT and PTTG1 by association of Ku70 might be important for the enhancement of the limited self-renewal activity of MSCs and for understanding the regulatory mechanisms of self-renewal.
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Affiliation(s)
- Hyun-Jung Lee
- Department of Biomedical Science, CHA University, 606-16 Yeoksam1-dong, Kangnam-Gu, Seoul, 135-097, Republic of Korea
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Stevens JB, Liu G, Abdallah BY, Horne SD, Ye KJ, Bremer SW, Ye CJ, Krawetz SA, Heng HH. Unstable genomes elevate transcriptome dynamics. Int J Cancer 2014; 134:2074-87. [PMID: 24122714 DOI: 10.1002/ijc.28531] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 09/10/2013] [Accepted: 09/26/2013] [Indexed: 01/15/2023]
Abstract
The challenge of identifying common expression signatures in cancer is well known, however the reason behind this is largely unclear. Traditionally variation in expression signatures has been attributed to technological problems, however recent evidence suggests that chromosome instability (CIN) and resultant karyotypic heterogeneity may be a large contributing factor. Using a well-defined model of immortalization, we systematically compared the pattern of genome alteration and expression dynamics during somatic evolution. Co-measurement of global gene expression and karyotypic alteration throughout the immortalization process reveals that karyotype changes influence gene expression as major structural and numerical karyotypic alterations result in large gene expression deviation. Replicate samples from stages with stable genomes are more similar to each other than are replicate samples with karyotypic heterogeneity. Karyotypic and gene expression change during immortalization is dynamic as each stage of progression has a unique expression pattern. This was further verified by comparing global expression in two replicates grown in one flask with known karyotypes. Replicates with higher karyotypic instability were found to be less similar than replicates with stable karyotypes. This data illustrates the karyotype, transcriptome, and transcriptome determined pathways are in constant flux during somatic cellular evolution (particularly during the macroevolutionary phase) and this flux is an inextricable feature of CIN and essential for cancer formation. The findings presented here underscore the importance of understanding the evolutionary process of cancer in order to design improved treatment modalities.
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9
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Forbes NE, Abdelbary H, Lupien M, Bell JC, Diallo JS. Exploiting tumor epigenetics to improve oncolytic virotherapy. Front Genet 2013; 4:184. [PMID: 24062768 PMCID: PMC3778850 DOI: 10.3389/fgene.2013.00184] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 08/29/2013] [Indexed: 12/20/2022] Open
Abstract
Oncolytic viruses (OVs) comprise a versatile and multi-mechanistic therapeutic platform in the growing arsenal of anticancer biologics. These replicating therapeutics find favorable conditions in the tumor niche, characterized among others by increased metabolism, reduced anti-tumor/antiviral immunity, and disorganized vasculature. Through a self-amplification that is dependent on multiple cancer-specific defects, these agents exhibit remarkable tumor selectivity. With several OVs completing or entering Phase III clinical evaluation, their therapeutic potential as well as the challenges ahead are increasingly clear. One key hurdle is tumor heterogeneity, which results in variations in the ability of tumors to support productive infection by OVs and to induce adaptive anti-tumor immunity. To this end, mounting evidence suggests tumor epigenetics may play a key role. This review will focus on the epigenetic landscape of tumors and how it relates to OV infection. Therapeutic strategies aiming to exploit the epigenetic identity of tumors in order to improve OV therapy are also discussed.
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Affiliation(s)
- Nicole E. Forbes
- Center for Innovative Cancer Research, Ottawa Hospital Research InstituteOttawa, ON, Canada
- Faculty of Medicine, University of OttawaOttawa, ON, Canada
| | - Hesham Abdelbary
- Center for Innovative Cancer Research, Ottawa Hospital Research InstituteOttawa, ON, Canada
- Faculty of Medicine, University of OttawaOttawa, ON, Canada
| | - Mathieu Lupien
- Ontario Cancer Institute, Princess Margaret Cancer Center/University Health NetworkToronto, ON, Canada
- Ontario Institute for Cancer ResearchToronto, ON, Canada
- Department of Medical Biophysics, University of TorontoToronto, ON, Canada
| | - John C. Bell
- Center for Innovative Cancer Research, Ottawa Hospital Research InstituteOttawa, ON, Canada
- Faculty of Medicine, University of OttawaOttawa, ON, Canada
| | - Jean-Simon Diallo
- Center for Innovative Cancer Research, Ottawa Hospital Research InstituteOttawa, ON, Canada
- Faculty of Medicine, University of OttawaOttawa, ON, Canada
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10
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Li C, Wang L, Su J, Zhang R, Fu L, Zhou Y. mRNA expression and hypermethylation of tumor suppressor genes apoptosis protease activating factor-1 and death-associated protein kinase in oral squamous cell carcinoma. Oncol Lett 2013; 6:280-286. [PMID: 23946818 PMCID: PMC3742820 DOI: 10.3892/ol.2013.1353] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 05/15/2013] [Indexed: 11/05/2022] Open
Abstract
Apoptosis protease activating factor-1 (Apaf-1) and death-associated protein kinase (DAPK) are p53 pathway-related genes that play significant roles in the activation of caspases, which are involved in mitochondrial-mediated apoptosis. The present study aimed to confirm the role of hyper-methylation of the Apaf-1 and DAPK gene promoter regions in oral squamous cell carcinoma (OSCC) and the effect of the demethylation drug, 5-aza-2'-deoxycytidine (DAC). mRNA from 53 OSCC samples, 23 normal oral mucosa samples and Tca8113 human tongue carcinoma cell lines was detected using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The DNA from each sample was analyzed using methylation-specific PCR (MSP). The Tca8113 cells were demethylated using DAC and the demethylation and re-expression of Apaf-1 and DAPK were analyzed. The Apaf-1 and DAPK mRNA expression index was decreased in 51 (96.23%) and 50 (94.34%) cases, respectively, in the tumor tissues. Hypermethylation of the Apaf-1 and DAPK promoter regions was detected in 46 (86.79%) and 38 (71.69%) cases, respectively. Promoter hypermethylation of the two genes correlated with a decreased mRNA expression in the tumor tissues. Subsequent to being treated with DAC, Apaf-1 and DAPK were demethylated and re-expressed in the Tca8113 cells. Apaf-1 and DAPK promoter hypermethylation may be associated with low gene expression in OSCC. Furthermore, a loss of Apaf-1 and DAPK expression may recover following demethylation. The data provide evidence that methylation exists in OSCC and may play a role in the development of this disease.
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Affiliation(s)
- Chunyan Li
- Departments of Implant Center, Jilin University, Changchun, Jilin 130011, P.R. China
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11
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Smith MC, Goddard ET, Perusina Lanfranca M, Davido DJ. hTERT extends the life of human fibroblasts without compromising type I interferon signaling. PLoS One 2013; 8:e58233. [PMID: 23472163 PMCID: PMC3589264 DOI: 10.1371/journal.pone.0058233] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 02/05/2013] [Indexed: 12/24/2022] Open
Abstract
Primary cells are often used to study viral replication and host-virus interactions as their antiviral pathways have not been altered or inactivated; however, their use is restricted by their short lifespan. Conventional methods to extend the life of primary cultures typically utilize viral oncogenes. Many of these oncogenes, however, perturb or inactivate cellular antiviral pathways, including the interferon (IFN) response. It has been previously shown that expression of the telomerase reverse transcriptase (TERT) gene extends the life of certain cell types. The effect that TERT expression has on the innate antiviral response to RNA- and DNA-containing viruses has not been examined. In the current study, we introduced the human TERT (hTERT) gene into a primary human embryonic lung (HEL-299) cell strain, which is known to respond to the type I IFN, IFN-β. We show that the resulting HEL-TERT cell line is capable of replicating beyond 100 population doublings without exhibiting signs of senescence. Treatment with IFN-β resulted in the upregulation of four model IFN stimulated genes (ISGs) in HEL-299 and HEL-TERT cells. Both cell lines supported the replication of herpes simplex virus type 1 (HSV-1) and vesicular stomatitis virus (VSV) and impaired the replication of both viruses upon IFN-β pretreatment. Introduction of the viral oncoprotein, simian virus 40 (SV40) large T-antigen, which is frequently used to immortalize cells, largely negated this effect. Taken together, our data indicate that expression of hTERT does not alter type 1 IFN signaling and/or the growth of two viruses, making this cell line a useful reagent for studying viral replication and virus-cell interactions.
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Affiliation(s)
- Miles C. Smith
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
| | - Erica T. Goddard
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
| | - Mirna Perusina Lanfranca
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
| | - David J. Davido
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas, United States of America
- * E-mail:
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13
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Auburger G, Klinkenberg M, Drost J, Marcus K, Morales-Gordo B, Kunz WS, Brandt U, Broccoli V, Reichmann H, Gispert S, Jendrach M. Primary skin fibroblasts as a model of Parkinson's disease. Mol Neurobiol 2012; 46:20-7. [PMID: 22350618 PMCID: PMC3443476 DOI: 10.1007/s12035-012-8245-1] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 02/03/2012] [Indexed: 01/28/2023]
Abstract
Parkinson's disease is the second most frequent neurodegenerative disorder. While most cases occur sporadic mutations in a growing number of genes including Parkin (PARK2) and PINK1 (PARK6) have been associated with the disease. Different animal models and cell models like patient skin fibroblasts and recombinant cell lines can be used as model systems for Parkinson's disease. Skin fibroblasts present a system with defined mutations and the cumulative cellular damage of the patients. PINK1 and Parkin genes show relevant expression levels in human fibroblasts and since both genes participate in stress response pathways, we believe fibroblasts advantageous in order to assess, e.g. the effect of stressors. Furthermore, since a bioenergetic deficit underlies early stage Parkinson's disease, while atrophy underlies later stages, the use of primary cells seems preferable over the use of tumor cell lines. The new option to use fibroblast-derived induced pluripotent stem cells redifferentiated into dopaminergic neurons is an additional benefit. However, the use of fibroblast has also some drawbacks. We have investigated PARK6 fibroblasts and they mirror closely the respiratory alterations, the expression profiles, the mitochondrial dynamics pathology and the vulnerability to proteasomal stress that has been documented in other model systems. Fibroblasts from patients with PARK2, PARK6, idiopathic Parkinson's disease, Alzheimer's disease, and spinocerebellar ataxia type 2 demonstrated a distinct and unique mRNA expression pattern of key genes in neurodegeneration. Thus, primary skin fibroblasts are a useful Parkinson's disease model, able to serve as a complement to animal mutants, transformed cell lines and patient tissues.
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Affiliation(s)
- Georg Auburger
- Experimental Neurology, Department of Neurology, Goethe University Hospital, Theodor Stern Kai 7, 60590 Frankfurt am Main, Germany
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Epigenetic silencing of IRF7 and/or IRF5 in lung cancer cells leads to increased sensitivity to oncolytic viruses. PLoS One 2011; 6:e28683. [PMID: 22194884 PMCID: PMC3237484 DOI: 10.1371/journal.pone.0028683] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 11/13/2011] [Indexed: 01/28/2023] Open
Abstract
Defective IFN signaling results in loss of innate immunity and sensitizes cells to enhanced cytolytic killing after Vesticular Stomatitis Virus (VSV) infection. Examination of the innate immunity status of normal human bronchial epithelial cells Beas2B and 7 lung cancer cells revealed that the abrogation of IFN signaling in cancer cells is associated with greater sensitivity to VSV infection. The disruption of the IFN pathway in lung cancer cell lines and primary tumor tissues is caused by epigenetic silencing of critical interferon responsive transcription factors IRF7 and/or IRF5. Although 5-aza-2′-deoxycytidine treatment fails to reactivate IRF7 and IRF5 expression or protect cells from VSV infection, manipulating IFN signaling by altering IRF expression changes the viral susceptibility of these cells. Lung cancer cells can be partially protected from viral killing using IRF5+IRF7 overexpression, whereas IFN pathway disruption by transfection of siRNAs to IRF5+IRF7 increases cells' vulnerability to viral infection. Therefore, IRF5 and IRF7 are key transcription factors in IFN pathway that determine viral sensitivity of lung cancer cells; the epigenetically impaired IFN pathway in lung cancer tissues provides potential biomarkers for successful selective killing of cancer cells by oncolytic viral therapy.
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Li Q, Tainsky MA. Higher miRNA tolerance in immortal Li-Fraumeni fibroblasts with abrogated interferon signaling pathway. Cancer Res 2011; 71:255-65. [PMID: 21199806 DOI: 10.1158/0008-5472.can-10-1452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The IFN pathway is abrogated in fibroblasts from Li-Fraumeni syndrome (LFS) patients during spontaneous cellular immortalization, a necessary step in carcinogenesis. Microarray profiling of differentially expressed microRNAs (miRNA) revealed that most miRNAs were upregulated in IFN pathway-defective MDAH087-10 fibroblasts compared with MDAH087-N cells with relatively normal IFN signaling. Overexpression of Dicer, a critical enzyme in miRNA biogenesis, promoted cell growth and colony formation in MDAH087-10 cells. However, double-stranded miRNA produced by Dicer enhanced the expression of IFN-stimulated genes in MDAH087-N cells resulting in significant cell death and reduced cell growth. Furthermore, manipulation of the IFN pathway in immortal LFS fibroblasts through transcription factor IRF7 reversed their response to Dicer overexpression due to changed IFN pathway activity. Dicer overexpressing MDAH087-N cells contained lower levels of miRNA than vector control, and conversely much higher miRNA expression was detected in Dicer-transfected MDAH087-10 cells. Therefore, cells with a defective IFN pathway have a higher miRNA tolerance than cells with normal IFN pathway. This work indicates for the first time that the IFN pathway as mediated through the transcription factor IRF7 must be disrupted to permit miRNA upregulation to occur in early carcinogenesis. The IFN pathway appears to provide a checkpoint for miRNA level tolerance and its abrogation leads to cellular immortalization.
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Affiliation(s)
- Qunfang Li
- Program in Molecular Biology and Genetics, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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Abstract
Cellular senescence is an irreversible growth arrest that is activated in normal cells upon shortening of telomere and other cellular stresses. Bypassing cellular senescence is a necessary step for cells to become immortal during oncogenic transformation. During the spontaneous immortalization of Li-Fraumeni Syndrome (LFS) fibroblasts, we found that CREG1 (Cellular Repressor of E1A-stimulated Genes 1) expression was decreased during immortalization and increased in senescence. Moreover, we found that repression of CREG1 expression occurs via an epigenetic mechanism, promoter DNA methylation. Ectopic expression of CREG1 in the immortal LFS cell lines decreases cell proliferation but does not directly induce senescence. We confirmed this in osteosarcoma and fibrosarcoma cancer cell lines, cancers commonly seen in Li-Fraumeni Syndrome. In addition, we found that p16 (INK4a) is also downregulated in immortal cells and that coexpression of CREG1 and p16 (INK4a) , an inhibitor of CDK4/6 and Rb phosphorylation, has a greater effect than either CREG1 and p16 (INK4a) alone to reduce cell growth, induce cell cycle arrest and cellular senescence in immortal LFS fibroblasts, osteosarcoma and fibrosarcoma cell lines. Moreover, cooperation of CREG1 and p16 (INK4a) inhibits the expression of cyclin A and cyclin B by inhibiting promoter activity thereby decreasing mRNA and protein levels; these proteins are required for S-phase entry and G2/M transition. In conclusion, this is the first evidence to demonstrate that CREG1 enhances p16 (INK4a) -induced senescence by transcriptional repression of cell cycle-regulated genes.
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Affiliation(s)
- Benchamart Moolmuang
- Department of Oncology, Wayne State University School of Medicine, Detroit, MI, USA
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17
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Choubey D, Duan X, Dickerson E, Ponomareva L, Panchanathan R, Shen H, Srivastava R. Interferon-inducible p200-family proteins as novel sensors of cytoplasmic DNA: role in inflammation and autoimmunity. J Interferon Cytokine Res 2010; 30:371-80. [PMID: 20187776 DOI: 10.1089/jir.2009.0096] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Deregulated innate immune responses that result in increased levels of type I interferons (IFNs) and stimulation of IFN-inducible genes are thought to contribute to chronic inflammation and autoimmunity. One family of IFN-inducible genes is the Ifi200 family, which includes the murine (eg, Ifi202a, Ifi202b, Ifi203, Ifi204, Mndal, and Aim2) and human (eg, IFI16, MNDA, IFIX, and AIM2) genes. Genes in the family encode structurally related proteins (the p200-family proteins), which share at least one partially conserved repeat of 200-amino acid (200-AA) residues. Consistent with the presence of 2 consecutive oligonucleotide/oligosaccharide-binding folds in the repeat, the p200-family proteins can bind to DNA. Additionally, these proteins (except the p202 proteins) also contain a pyrin (PYD) domain in the N-terminus. Increased expression of p202 proteins in certain strains of female mice is associated with lupus-like disease. Interestingly, only the Aim2 protein is conserved between the mouse and humans. Several recent studies have provided evidence that the Aim2 and p202 proteins can recognize DNA in cytoplasm and the Aim2 protein upon sensing DNA can form a caspase-1-activating inflammasome. In this review, we discuss how the ability of p200-family proteins to sense cytoplasmic DNA may contribute to the development of chronic inflammation and associated diseases.
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Affiliation(s)
- Divaker Choubey
- Department of Environmental Health, University of Cincinnati, Cincinnati, Ohio 45267, USA.
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Paladino P, Collins SE, Mossman KL. Cellular localization of the herpes simplex virus ICP0 protein dictates its ability to block IRF3-mediated innate immune responses. PLoS One 2010; 5:e10428. [PMID: 20454685 PMCID: PMC2861674 DOI: 10.1371/journal.pone.0010428] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2010] [Accepted: 04/07/2010] [Indexed: 12/19/2022] Open
Abstract
Interferon regulatory factor 3 (IRF3) is important for innate antiviral responses; accordingly, many viruses target and inactivate IRF3. The ability of the Herpes simplex virus type 1 (HSV-1) immediate early protein ICP0 to inhibit IRF3 is controversial and has not been studied solely in the context of a wild type HSV-1 infection. Discrepancies in the literature surround the mechanism by which ICP0 antagonizes the IRF3 pathway, the cellular localization of ICP0 inhibitory activity and the ability of ICP0 to interfere with interferon and interferon-stimulated gene induction. In this study, we set out to investigate the role of ICP0 localization and the requirement of the proteasome during the inhibition of IRF3 activation within the context of an HSV-1 infection. Collectively, the results presented herein demonstrate that incoming wild type HSV-1 activates IRF3 and that de novo produced ICP0 prevents sustained IRF3 activation following its translocation from the nucleus to the cytoplasm. While previous studies implicate the E3 ubiquitin ligase domain of ICP0 in mediating its biological functions, including the inhibition of IRF3, we show that cytoplasmic ICP0 does not require the proteasome for this activity. Instead, proteasome function is required to localize ICP0 to the cytoplasm where it mediates its inhibitory effect independent of E3 ubiquitin ligase activity. The importance of these findings is discussed within the context of an HSV-1 infection.
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Affiliation(s)
- Patrick Paladino
- Department of Pathology and Molecular Medicine, Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Susan E. Collins
- Department of Pathology and Molecular Medicine, Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Karen L. Mossman
- Department of Pathology and Molecular Medicine, Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
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19
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Interferon-inducible IFI16, a negative regulator of cell growth, down-regulates expression of human telomerase reverse transcriptase (hTERT) gene. PLoS One 2010; 5:e8569. [PMID: 20052289 PMCID: PMC2797294 DOI: 10.1371/journal.pone.0008569] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Accepted: 12/11/2009] [Indexed: 01/07/2023] Open
Abstract
Background Increased levels of interferon (IFN)-inducible IFI16 protein (encoded by the IFI16 gene located at 1q22) in human normal prostate epithelial cells and diploid fibroblasts (HDFs) are associated with the onset of cellular senescence. However, the molecular mechanisms by which the IFI16 protein contributes to cellular senescence-associated cell growth arrest remain to be elucidated. Here, we report that increased levels of IFI16 protein in normal HDFs and in HeLa cells negatively regulate the expression of human telomerase reverse transcriptase (hTERT) gene. Methodology/Principal Findings We optimized conditions for real-time PCR, immunoblotting, and telomere repeat amplification protocol (TRAP) assays to detect relatively low levels of hTERT mRNA, protein, and telomerase activity that are found in HDFs. Using the optimized conditions, we report that treatment of HDFs with inhibitors of cell cycle progression, such as aphidicolin or CGK1026, which resulted in reduced steady-state levels of IFI16 mRNA and protein, was associated with increases in hTERT mRNA and protein levels and telomerase activity. In contrast, knockdown of IFI16 expression in cells increased the expression of c-Myc, a positive regulator of hTERT expression. Additionally, over-expression of IFI16 protein in cells inhibited the c-Myc-mediated stimulation of the activity of hTERT-luc-reporter and reduced the steady-state levels of c-Myc and hTERT. Conclusions/Significance These data demonstrated that increased levels of IFI16 protein in HDFs down-regulate the expression of hTERT gene. Our observations will serve basis to understand how increased cellular levels of the IFI16 protein may contribute to certain aging-dependent diseases.
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Abstract
Oncogene-induced cellular senescence constitutes a strong anti-proliferative response, which can be set in motion following either oncogene activation or loss of tumour suppressor signalling. It serves to limit the expansion of early neoplastic cells and as such is a potent cancer-protective response to oncogenic events. Recently emerging evidence points to a crucial role in oncogene-induced cellular senescence for the 'senescence-messaging secretome' or SMS, setting the stage for cross-talk between senescent cells and their environment. How are such signals integrated into a coordinated response and what are the implications of this unexpected finding?
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Affiliation(s)
- Thomas Kuilman
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
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21
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Li Q, Tang L, Roberts PC, Kraniak JM, Fridman AL, Kulaeva OI, Tehrani OS, Tainsky MA. Interferon regulatory factors IRF5 and IRF7 inhibit growth and induce senescence in immortal Li-Fraumeni fibroblasts. Mol Cancer Res 2008; 6:770-84. [PMID: 18505922 DOI: 10.1158/1541-7786.mcr-07-0114] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cellular immortalization is one of the prerequisite steps in carcinogenesis. By gene expression profiling, we have found that genes in the interferon (IFN) pathway were dysregulated during the spontaneous cellular immortalization of fibroblasts from Li-Fraumeni syndrome (LFS) patients with germ-line mutations in p53. IFN signaling pathway genes were down-regulated by epigenetic silencing during immortalization, and some of these same IFN-regulated genes were activated during replicative senescence. Bisulfite sequencing of the promoter regions of two IFN regulatory transcription factors (IRF5 and IRF7) revealed that IRF7, but not IRF5, was epigenetically silenced by methylation of CpG islands in immortal LFS cells. The induction of IRF7 gene by IFNalpha in immortal LFS cells was potentiated by pretreatment with the demethylation agent 5-aza-2'-deoxycytidine. Overexpression of IRF5 and IRF7 revealed that they can act either alone or in tandem to activate other IFN-regulated genes. In addition, they serve to inhibit the proliferation rate and induce a senescence-related phenotype in immortal LFS cells. Furthermore, polyinosinic:polycytidylic acid treatment of the IRF-overexpressing cells showed a more rapid induction of several IFN-regulated genes. We conclude that the epigenetic inactivation of the IFN pathway plays a critical role in cellular immortalization, and the reactivation of IFN-regulated genes by transcription factors IRF5 and/or IRF7 is sufficient to induce cellular senescence. The IFN pathway may provide valuable molecular targets for therapeutic interventions at early stages of cancer development.
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Affiliation(s)
- Qunfang Li
- Program in Molecular Biology and Genetics, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, 110 East Warren, Detroit, MI 48201, USA
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22
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Fridman AL, Tainsky MA. Critical pathways in cellular senescence and immortalization revealed by gene expression profiling. Oncogene 2008; 27:5975-87. [PMID: 18711403 DOI: 10.1038/onc.2008.213] [Citation(s) in RCA: 204] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Bypassing cellular senescence and becoming immortal is a prerequisite step in the tumorigenic transformation of a cell. It has long been known that loss of a key tumor suppressor gene, such as p53, is necessary, but not sufficient, for spontaneous cellular immortalization. Therefore, there must be additional mutations and/or epigenetic alterations required for immortalization to occur. Early work on these processes included somatic cell genetic studies to estimate the number of senescence genes, and microcell-mediated transfer of chromosomes into immortalized cells to identify putative senescence-inducing genetic loci. These principal studies laid the foundation for the field of senescence/immortalization, but were labor intensive and the results were somewhat limited. The advent of gene expression profiling and bioinformatics analysis greatly facilitated the identification of genes and pathways that regulate cellular senescence/immortalization. In this review, we present the findings of several gene expression profiling studies and supporting functional data, where available. We identified universal genes regulating senescence/immortalization and found that the key regulator genes represented six pathways: the cell cycle pRB/p53, cytoskeletal, interferon-related, insulin growth factor-related, MAP kinase and oxidative stress pathway. The identification of the genes and pathways regulating senescence/immortalization could provide novel molecular targets for the treatment and/or prevention of cancer.
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Affiliation(s)
- A L Fridman
- Department of Pathology, Program in Molecular Biology and Genetics, Barbara Ann Karmanos Cancer Institute, Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
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23
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Fridman AL, Rosati R, Li Q, Tainsky MA. Epigenetic and functional analysis of IGFBP3 and IGFBPrP1 in cellular immortalization. Biochem Biophys Res Commun 2007; 357:785-91. [PMID: 17451653 DOI: 10.1016/j.bbrc.2007.04.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 04/03/2007] [Accepted: 04/03/2007] [Indexed: 11/29/2022]
Abstract
Carcinogenic transformation of a cell requires bypassing senescence and becoming immortalized. A cellular senescence-like phenotype can be induced in immortal Li-Fraumeni syndrome (LFS) cells by treating them with the DNA methyltransferase inhibitor 5-aza-deoxycytidine. Our microarray-based expression profiling studies of spontaneously immortalized LFS cell lines identified genes that may provide the growth advantage required for the cells to become immortal. Several members of the IGFBP superfamily of genes fit the profile of genes involved in immortalization: silenced during immortalization and reactivated by 5-aza-deoxycytidine. Overexpression of IGFBP3 or IGFBPrP1 in the immortal LFS cell lines suppressed cell growth and inhibited colony formation. Both genes have the expression pattern of an epigenetically regulated gene and contain CpG islands suitable for methylation-dependent silencing. Analysis of how IGFBPs regulate immortalization will lead to a better understanding of this process and may lead to novel methods for the prevention and treatment of cancer.
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Affiliation(s)
- Aviva Levine Fridman
- Program in Molecular Biology and Genetics, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine, 110 East Warren Avenue, Detroit, MI 48201, USA
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