scholarly journals A Comprehensive Analysis of Human Endogenous Retroviruses HERV-K (HML.2) from Teratocarcinoma Cell Lines and Detection of Viral Cargo in Microvesicles

2021 ◽  
Vol 22 (22) ◽  
pp. 12398
Author(s):  
Vladimir A. Morozov ◽  
Alexey V. Morozov
Keyword(s):  
Cell Lines ◽  
Malignant Tumors ◽  
Gradient Centrifugation ◽  
Buoyant Density ◽  
Particle Morphology ◽  
Endogenous Retroviruses ◽  
Cdna Clones ◽  
Teratocarcinoma Cell ◽  
Human Endogenous Retroviruses ◽  
Gh Cells

About 8% of our genome is composed of sequences from Human Endogenous Retroviruses (HERVs). The HERV-K (HML.2) family, here abbreviated HML.2, is able to produce virus particles that were detected in cell lines, malignant tumors and in autoimmune diseases. Parameters and properties of HML.2 released from teratocarcinoma cell lines GH and Tera-1 were investigated in detail. In most experiments, analyzed viruses were purified by density gradient centrifugation. HML.2 structural proteins, reverse transcriptase (RT) activity, viral RNA (vRNA) and particle morphology were analyzed. The HML.2 markers were predominantly detected in fractions with a buoyant density of 1.16 g/cm3. Deglycosylation of TM revealed truncated forms of transmembrane (TM) protein. Free virions and extracellular vesicles (presumably microvesicles—MVs) with HML.2 elements, including budding intermediates, were detected by electron microscopy. Viral elements and assembled virions captured and exported by MVs can boost specific immune responses and trigger immunomodulation in recipient cells. Sequencing of cDNA clones demonstrated exclusive presence of HERV-K108 env in HML.2 from Tera-1 cells. Not counting two recombinant variants, four known env sequences were found in HML.2 from GH cells. Obtained results shed light on parameters and morphology of HML.2. A possible mechanism of HML.2-induced diseases is discussed.

scholarly journals Extracellular Vesicles Released by Colorectal Cancer Cell Lines Modulate Innate Immune Response in Zebrafish Model: The Possible Role of Human Endogenous Retroviruses

2019 ◽  
Vol 20 (15) ◽  
pp. 3669 ◽  
Author(s):  
Luca Ferrari ◽  
Marco Cafora ◽  
Federica Rota ◽  
Mirjam Hoxha ◽  
Simona Iodice ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Immune Response ◽  
Cell Lines ◽  
Cancer Cell ◽  
Innate Immune Response ◽  
Colorectal Adenocarcinoma ◽  
Innate Immune ◽  
Endogenous Retroviruses ◽  
Human Endogenous Retroviruses ◽  
Colorectal Cancer Cell Lines

Extracellular vesicles (EVs) are important components of the metastatic niche and are crucial in infiltration, metastasis, and immune tolerance processes during tumorigenesis. We hypothesized that human endogenous retroviruses (HERV) positive EVs derived from tumor cellsmay have a role in modulating the innate immune response. The study was conducted in two different colorectal cancer cell lines, representing different stages of cancer development: Caco-2, derived from a non-metastatic colorectal adenocarcinoma, and SK-CO-1, derived from metastatic colorectal adenocarcinoma (ascites). Both cell lines were treated with decitabine to induce global hypomethylation and to reactivate HERV expression. EVs were quantified by nanoparticle tracking analysis, and HERV-positive EV concentrations were measured by flow cytometry. The effect of EVs isolated from both untreated and decitabine-treated cells on the innate immune response was evaluated by injecting them in zebrafish embryos and then assessing Interleukin 1β (IL1-β), Interleukin 10 (IL-10), and the myeloperoxidase (mpx) expression levels by real-time qPCR. Interestingly, HERV-K positive EVs concentrations were significantly associated with a reduced expression of IL1-β and mpx, supporting our hypothesis that HERV-positive EVs may act as immunomodulators in tumor progression. The obtained results open new perspectives about the modulation of the immune response in cancer therapy.

The potential of retroviral vectors to cotransfer human endogenous retroviruses (HERVs) from human packaging cell lines

Gene ◽  
2007 ◽  
Vol 390 (1-2) ◽  
pp. 175-179 ◽  
Author(s):  
Udo Zeilfelder ◽  
Oliver Frank ◽  
Sandra Sparacio ◽  
Ulrike Schön ◽  
Valerie Bosch ◽  
...  
Keyword(s):  
Cell Lines ◽  
Retroviral Vectors ◽  
Endogenous Retroviruses ◽  
Human Endogenous Retroviruses ◽  
Packaging Cell

scholarly journals Human endogenous retrovirus-W envelope (syncytin) is expressed in both villous and extravillous trophoblast populations

2006 ◽  
Vol 87 (7) ◽  
pp. 2067-2071 ◽  
Author(s):  
A. Muir ◽  
A. M. L. Lever ◽  
A. Moffett
Keyword(s):  
Cell Lines ◽  
First Trimester ◽  
Endogenous Retrovirus ◽  
Endogenous Retroviruses ◽  
Extravillous Trophoblast ◽  
Human Endogenous Retrovirus ◽  
Human Trophoblast ◽  
Human Endogenous Retroviruses ◽  
Normal Tissues ◽  
Villous Trophoblast

The placenta is unique amongst normal tissues in transcribing numerous different human endogenous retroviruses at high levels. In this study, RT-PCR and immunohistochemistry were used to investigate the expression of syncytin in human trophoblast. Syncytin transcripts were found in first-trimester trophoblast cells with both villous and extravillous phenotypes and also in the JAR and JEG-3 choriocarcinoma cell lines. Syncytin protein was detected in villous trophoblast and in all extravillous trophoblast subpopulations of first- and second-trimester placental tissues. It was also present in ectopic trophoblast from tubal implantations. This study confirms that syncytin is expressed widely by a variety of normal human trophoblast populations, as well as choriocarcinoma cell lines.

scholarly journals Formation of HERV-K and HERV-Fc1 Envelope Family Members is Suppressed on Transcriptional and Translational Level

2020 ◽  
Vol 21 (21) ◽  
pp. 7855
Author(s):  
Victoria Gröger ◽  
Lisa Wieland ◽  
Marcel Naumann ◽  
Ann-Christin Meinecke ◽  
Beate Meinhardt ◽  
...  
Keyword(s):  
Cell Lines ◽  
Inflammatory Diseases ◽  
Envelope Proteins ◽  
Viral Envelope ◽  
Endogenous Retroviruses ◽  
Open Reading Frames ◽  
Extrinsic Factors ◽  
Human Endogenous Retroviruses ◽  
Mammalian Cell Lines ◽  
Translational Level

The human genome comprises 8% sequences of retroviral origin, so-called human endogenous retroviruses (HERVs). Most of these proviral sequences are defective, but some possess open reading frames. They can lead to the formation of viral transcripts, when activated by intrinsic and extrinsic factors. HERVs are thought to play a pathological role in inflammatory diseases and cancer. Since the consequences of activated proviral sequences in the human body are largely unexplored, selected envelope proteins of human endogenous retroviruses associated with inflammatory diseases, namely HERV-K18, HERV-K113, and HERV-Fc1, were investigated in the present study. A formation of glycosylated envelope proteins was demonstrated in different mammalian cell lines. Nevertheless, protein maturation seemed to be incomplete as no transport to the plasma membrane was observed. Instead, the proteins remained in the ER where they induced the expression of genes involved in unfolded protein response, such as HSPA5 and sXBP1. Furthermore, low expression levels of native envelope proteins were increased by codon optimization. Cell-free expression systems showed that both the transcriptional and translational level is affected. By generating different codon-optimized variants of HERV-K113 envelope, the influence of single rare t-RNA pools in certain cell lines was demonstrated. The mRNA secondary structure also appears to play an important role in the translation of the tested viral envelope proteins. In summary, the formation of certain HERV proteins is basically possible. However, their complete maturation and thus full biologic activity seems to depend on additional factors that might be disease-specific and await elucidation in the future.

scholarly journals Molecular Characterization and Placental Expression of HERV-W, a New Human Endogenous Retrovirus Family

1999 ◽  
Vol 73 (2) ◽  
pp. 1175-1185 ◽  
Author(s):  
Jean-Luc Blond ◽  
Frédéric Besème ◽  
Laurent Duret ◽  
Olivier Bouton ◽  
Frédéric Bedin ◽  
...  
Keyword(s):  
Endogenous Retrovirus ◽  
Endogenous Retroviruses ◽  
Open Reading Frames ◽  
Primer Binding Site ◽  
Human Endogenous Retrovirus ◽  
Cdna Clones ◽  
Human Endogenous Retroviruses ◽  
Herv Family ◽  
Flanking Sequences ◽  
Reading Frames

ABSTRACT The multiple sclerosis-associated retrovirus (MSRV) isolated from plasma of MS patients was found to be phylogenetically and experimentally related to human endogenous retroviruses (HERVs). To characterize the MSRV-related HERV family and to test the hypothesis of a replication-competent HERV, we have investigated the expression of MSRV-related sequences in healthy tissues. The expression of MSRV-related transcripts restricted to the placenta led to the isolation of overlapping cDNA clones from a cDNA library. These cDNAs spanned a 7.6-kb region containing gag, pol, and env genes; RU5 and U3R flanking sequences; a polypurine tract; and a primer binding site (PBS). As this PBS showed similarity to avian retrovirus PBSs used by tRNATrp, this new HERV family was named HERV-W. Several genomic elements were identified, one of them containing a complete HERV-W unit, spanning all cDNA clones. Elements of this multicopy family were not replication competent, asgag and pol open reading frames (ORFs) were interrupted by frameshifts and stop codons. A complete ORF putatively coding for an envelope protein was found both on the HERV-W DNA prototype and within an RU5-env-U3R polyadenylated cDNA clone. Placental expression of 8-, 3.1-, and 1.3-kb transcripts was observed, and a putative splicing strategy was described. The apparently tissue-restricted HERV-W long terminal repeat expression is discussed with respect to physiological and pathological contexts.

Role of Human Endogenous Retroviruses in Lymphoma Pathogenesis and a Possible Biomarker of Disease

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3751-3751 ◽  
Author(s):  
Scott D. Gitlin ◽  
Rafael Contreras- Galindo ◽  
Mark H. Kaplan ◽  
David M. Markovitz
Keyword(s):  
Human Genome ◽  
Cell Lines ◽  
Endogenous Retroviruses ◽  
Human Endogenous Retrovirus ◽  
Hiv Positive ◽  
Human Endogenous Retroviruses ◽  
Viral Expression ◽  
Very High

Abstract Actively replicating retroviruses entered hominid species millions of years ago and through mutations preventing replication now exist as 8% of the human genome. Active retroviral particles and antigens from the supposedly dormant human endogenous retrovirus, HERV-K (HML2), have been identified in several cancer cell lines. We have recently demonstrated very high RNA titers of HERV-K (HML2) in the plasma of HIV positive individuals by nucleic acid sequence-based amplification (NASBA) and RT-PCR. We now demonstrate very high HERV-K (HML2) RNA titers in the plasma of patients with HIV positive and HIV negative non-Hodgkin lymphoma (NHL) and in Hodgkin Disease (HD), but not in normal individuals. Different copies of HERV-K (HML-2) present throughout the human genome exist as Type 1 viruses which encode a new oncoprotein, NP9, or as Type 2 viruses which encode a functional envelope (env) and express the Rec oncoprotein. Both Types 1 and 2 viruses appear in NHLs but only Type 1 appears in the plasma of those with HD. HERV-K (HML2) Env and Gag proteins, Env and Gag RNA, and Reverse Transcriptase (RT) activity are isolated from patients with a variety of NHLs, but not in normal controls or in patients with non-malignant diseases. Viral titers dramatically decrease, up to an approximately 7.5 log drop, when patients with NHL or HD go into remission following treatment. To further establish the presence of functional viruses in NHL and HD, immuno-gold electron microscopy allowed demonstration of HERV-K (HML2) particles in the plasma of lymphoma patients. Preliminary analysis of the effect of antiretroviral agents on cell lines infected with HERV-K (HML2) demonstrate a drug class-specific reduction in viral expression at drug concentration levels that range from 0.125 – 1 mcg/mL. In conclusion, we have demonstrated evidence that human endogenous retroviruses are found in the plasma of patients with NHL and HD, suggesting that these viruses, previously presumed to be inactive, may play a role in lymphoma pathogenesis. The observation that viral expression parallels declines in disease activity with treatment of disease may allow use of HERV-K (HML2) expression as a biomarker of lymphoma activity. The role of the HERV-K (HML2)-encoded oncoproteins in disease pathogenesis is under study, as is the potential role of antiretroviral therapy for these malignancies.

scholarly journals A Human Endogenous Retrovirus Suppresses Translation of an Associated Fusion Transcript, PLA2L

1998 ◽  
Vol 72 (7) ◽  
pp. 6164-6168 ◽  
Author(s):  
Paul E. Kowalski ◽  
Dixie L. Mager
Keyword(s):  
Cell Lines ◽  
Fusion Transcript ◽  
Endogenous Retrovirus ◽  
Full Length ◽  
Endogenous Retroviruses ◽  
Human Endogenous Retrovirus ◽  
Stem Loop ◽  
Teratocarcinoma Cell ◽  
Reading Frame ◽  
High Level

ABSTRACT Human endogenous retroviruses (HERVs) are repetitive, noninfectious chromosomal elements degenerated from exogenous retroviruses. The HERV-H family is composed of approximately 1,000 elements which are dispersed throughout the human genome. We have shown previously that an HERV-H element splices into a downstream locus, termed PLA2L, which has a large open reading frame (ORF) containing two domains with phospholipase A2 homology. Over half of the putative 5′ untranslated region (5′ UTR) of the resulting fusion transcript is derived from HERV-H long-terminal-repeat and internal sequences. As 5′ UTRs are known to modulate translation initiation, we tested for possible effects upon gene expression at the translation level due to the 5′ fusion with HERV-H sequences. No PLA2L protein was detected in teratocarcinoma cell lines in which PLA2L mRNA is abundantly expressed. In addition, despite a high level of transcription, no protein synthesis was detected when the full-length PLA2L cDNA was expressed in COS cells. Upon removal of the 5′-terminal HERV-H sequences, PLA2L protein was seen in transfectants. The 5′ UTR contains both small ORFs and a strong predicted RNA secondary structure, both of which have been shown to contribute to translation suppression. The HERV-H sequences, combined with a unique PLA2L 5′ UTR sequence, form a predicted RNA stem-loop that has a stability greater than that proposed to negatively affect translation. Interestingly, this stem-loop is abolished when the HERV-H sequences are removed. We hypothesize that the PLA2L 5′ HERV-H sequences function as an abnormally long and complex 5′ UTR, resulting in suppression of translation in both teratocarcinoma cell lines and full-length cDNA transfectants. This is the first known example of a endogenous retrovirus integration affecting expression of a heterologous human gene at the translational level.

Die Anämie bei malignen Tumorerkrankungen

1989 ◽  
Vol 28 (06) ◽  
pp. 247-254
Author(s):  
E. Aulbert
Keyword(s):  
Malignant Tumors ◽  
Gradient Centrifugation ◽  
Tumor Resection ◽  
Hemoglobin Concentration ◽  
Limiting Factor ◽  
Novikoff Hepatoma ◽  
Tumor Mass ◽  
Lysosomal Fraction ◽  
Proliferation Activity ◽  
Morris Hepatoma

The cellular uptake and lysosomal accumulation of 67Ga-labelled transferrin within tumors of different malignancy were examined using tissue fractionation and immunological techniques. As tumor models the slowly growing Morris hepatoma 5123C, the moderately growing Novikoff hepatoma and the fast and aggressive Yoshida hepatoma AH 130 were investigated. Isolation of subcellular fractions of tumor homogenates was performed by differential centrifugation and density-gradient centrifugation. The intracellular 67Gatransferrin was found to be highly concentrated within the purified lysosomes. The transferrin within the lysosomal fraction was identified by radial immunodiffusion technique using monospecific antiserum. The accumulation of 67Gatransferrin by the tumors resulted in a faster disappearance of 67Ga-transferrin from the blood. This loss of circulating 67Ga-transferrin correlated with the proliferation activity and the spread of the tumors. Since transferrin is indispensible for the utilization of iron by the heme-synthesizing red cell precursors, transferrin concentration in the blood is the limiting factor for the utilization of iron in hemoglobin synthesis. Thus, in a further series of experiments we investigated the development of anemia in tumor-bearing rats. With increasing tumor mass a progressive fall of hemoglobin concentration was found. The anemia was more severe in the faster growing Novikoff hepatoma than in the slowly growing Morris hepatoma. The most significant reduction of hemoglobin concentration was found in the very fast growing Yoshida hepatoma. After total tumor resection hemoglobin concentration and red blood cell count normalized completely within 6-8 weeks. We conclude from these data that the uptake of transferrin by the tumor cells results in a faster disappearance of transferrin from the blood. This loss of circulating transferrin correlates with tumor mass and proliferation activity and is one of the factors responsible for the anemia seen in patients with malignant tumors.

Expression of human endogenous retroviruses and associated transcripts in Hodgkin lymphoma cells

2020 ◽  
Author(s):  
K Engel ◽  
A Krüger ◽  
V Vandrey ◽  
J Schneider ◽  
I Volkmer ◽  
...  
Keyword(s):  
Hodgkin Lymphoma ◽  
Endogenous Retroviruses ◽  
Lymphoma Cells ◽  
Human Endogenous Retroviruses

The nuclear 3,5,3'-triiodothyronine receptor in human leukaemic cell lines

1984 ◽  
Vol 105 (3) ◽  
pp. 429-432 ◽  
Author(s):  
Juan Bernal ◽  
Leif C. Andersson
Keyword(s):  
Growth Hormone ◽  
Cell Line ◽  
Cell Lines ◽  
Rat Liver ◽  
Association Constant ◽  
Erythroid Differentiation ◽  
Leukaemic Cell ◽  
Cells In Culture ◽  
Gh Cells ◽  
High Concentrations

Abstract. The 3,5,3'-triiodothyronine (T3) receptor has been studied in a series of continuously growing human leukaemic cell lines. High concentrations of receptor were found in the erythroblastoid cell line K-562. T3 was bound to the nuclei of these cells with an association constant of 3.4 × 109 m−1, and capacity 104 fmol/100 μg DNA, or 8700 molecules/nucleus. This capacity is comparable to that of rat liver or growth hormone producing cells (GH cells) in culture, and suggests that the K-562 cell line could be a useful model for the study of T3 action on erythroid differentiation.

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