23 results on '"Ramos da Silva S"'
Search Results
2. Kaposi's sarcoma-associated herpesvirus infection and Kaposi's sarcoma in Brazil
- Author
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Ramos-da-Silva, S., primary, Elgui-de-Oliveira, D., additional, Borges, L., additional, and Bacchi, C.E., additional
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- 2006
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3. Molecular and immune signatures, and pathological trajectories of fatal COVID-19 lungs defined by in situ spatial single-cell transcriptome analysis.
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Das A, Meng W, Liu Z, Hasib MM, Galloway H, Ramos da Silva S, Chen L, Sica GL, Paniz-Mondolfi A, Bryce C, Grimes Z, Sordillo EM, Cordon-Cardo C, Rivera KP, Flores M, Chiu YC, Huang Y, and Gao SJ
- Subjects
- Humans, SARS-CoV-2 genetics, Endothelial Cells, Single-Cell Gene Expression Analysis, Angiotensin-Converting Enzyme 2 genetics, Angiotensin-Converting Enzyme 2 metabolism, Lung pathology, COVID-19 pathology
- Abstract
Despite intensive studies during the last 3 years, the pathology and underlying molecular mechanism of coronavirus disease 2019 (COVID-19) remain poorly defined. In this study, we investigated the spatial single-cell molecular and cellular features of postmortem COVID-19 lung tissues using in situ sequencing (ISS). We detected 10 414 863 transcripts of 221 genes in whole-slide tissues and segmented them into 1 719 459 cells that were mapped to 18 major parenchymal and immune cell types, all of which were infected by SARS-CoV-2. Compared with the non-COVID-19 control, COVID-19 lungs exhibited reduced alveolar cells (ACs) and increased innate and adaptive immune cells. We also identified 19 differentially expressed genes in both infected and uninfected cells across the tissues, which reflected the altered cellular compositions. Spatial analysis of local infection rates revealed regions with high infection rates that were correlated with high cell densities (HIHD). The HIHD regions expressed high levels of SARS-CoV-2 entry-related factors including ACE2, FURIN, TMPRSS2 and NRP1, and co-localized with organizing pneumonia (OP) and lymphocytic and immune infiltration, which exhibited increased ACs and fibroblasts but decreased vascular endothelial cells and epithelial cells, mirroring the tissue damage and wound healing processes. Sparse nonnegative matrix factorization (SNMF) analysis of niche features identified seven signatures that captured structure and immune niches in COVID-19 tissues. Trajectory inference based on immune niche signatures defined two pathological routes. Trajectory A primarily progressed with increased NK cells and granulocytes, likely reflecting the complication of microbial infections. Trajectory B was marked by increased HIHD and OP, possibly accounting for the increased immune infiltration. The OP regions were marked by high numbers of fibroblasts expressing extremely high levels of COL1A1 and COL1A2. Examination of single-cell RNA-seq data (scRNA-seq) from COVID-19 lung tissues and idiopathic pulmonary fibrosis (IPF) identified similar cell populations consisting mainly of myofibroblasts. Immunofluorescence staining revealed the activation of IL6-STAT3 and TGF-β-SMAD2/3 pathways in these cells, likely mediating the upregulation of COL1A1 and COL1A2 and excessive fibrosis in the lung tissues. Together, this study provides a spatial single-cell atlas of cellular and molecular signatures of fatal COVID-19 lungs, which reveals the complex spatial cellular heterogeneity, organization, and interactions that characterized the COVID-19 lung pathology., (© 2023 Wiley Periodicals LLC.)
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- 2023
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4. SARS-CoV-2 pseudovirus infectivity and expression of viral entry-related factors ACE2, TMPRSS2, Kim-1, and NRP-1 in human cells from the respiratory, urinary, digestive, reproductive, and immune systems.
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Zhang F, Li W, Feng J, Ramos da Silva S, Ju E, Zhang H, Chang Y, Moore PS, Guo H, and Gao SJ
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- Blotting, Western, COVID-19 metabolism, COVID-19 virology, Cell Line, Cells, Cultured, Fluorescent Antibody Technique, Gastrointestinal Tract cytology, Genitalia cytology, Humans, Immune System cytology, Respiratory System cytology, Angiotensin-Converting Enzyme 2 metabolism, Gastrointestinal Tract virology, Genitalia virology, Hepatitis A Virus Cellular Receptor 1 metabolism, Immune System virology, Neuropilin-1 metabolism, Respiratory System virology, SARS-CoV-2 physiology, Serine Endopeptidases metabolism, Virus Internalization
- Abstract
Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a wide spectrum of syndromes involving multiple organ systems and is primarily mediated by viral spike (S) glycoprotein through the receptor-binding domain (RBD) and numerous cellular proteins including ACE2, transmembrane serine protease 2 (TMPRSS2), kidney injury molecule-1 (Kim-1), and neuropilin-1 (NRP-1). In this study, we examined the entry tropism of SARS-CoV-2 and SARS-CoV using S protein-based pseudoviruses to infect 22 cell lines and 3 types of primary cells isolated from respiratory, urinary, digestive, reproductive, and immune systems. At least one cell line or type of primary cell from each organ system was infected by both pseudoviruses. Infection by pseudoviruses is effectively blocked by S1, RBD, and ACE2 recombinant proteins, and more weakly by Kim-1 and NRP-1 recombinant proteins. Furthermore, cells with robust SARS-CoV-2 pseudovirus infection had strong expression of either ACE2 or Kim-1 and NRP-1 proteins. ACE2 glycosylation appeared to be critical for the infections of both viruses as there was a positive correlation between infectivity of either SARS-CoV-2 or SARS-CoV pseudovirus with the level of glycosylated ACE2 (gly-ACE2). These results reveal that SARS-CoV-2 cell entry could be mediated by either an ACE2-dependent or -independent mechanism, thus providing a likely molecular basis for its broad tropism for a wide variety of cell types., (© 2021 Wiley Periodicals LLC.)
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- 2021
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5. Reversible switching of primary cells between normal and malignant state by oncogenic virus KSHV and CRISPR/Cas9-mediated targeting of a major viral latent protein.
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Ju E, Li T, Ramos da Silva S, Markazi A, and Gao SJ
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- Animals, Antigens, Viral metabolism, Apoptosis, CRISPR-Associated Protein 9 genetics, CRISPR-Associated Protein 9 metabolism, Cell Cycle, Cell Proliferation, Gene Knockout Techniques, Genome, Viral genetics, Herpesvirus 8, Human pathogenicity, Humans, Lymphoma, Primary Effusion pathology, Mesenchymal Stem Cells, Nuclear Proteins metabolism, Oncogenic Viruses pathogenicity, RNA, Guide, CRISPR-Cas Systems genetics, Rats, Virus Latency genetics, Antigens, Viral genetics, CRISPR-Cas Systems, Cell Transformation, Neoplastic genetics, Herpesvirus 8, Human genetics, Nuclear Proteins genetics, Oncogenic Viruses genetics
- Abstract
Viral infection has been implicated in the pathogenesis of a plethora of human diseases. Although antiviral therapies effectively confront the viral spread and infection, how to completely eradicate the viral genome from infected cells remains a challenge. In this study, we demonstrated the reversible switching of primary cells between normal and malignant states by an oncogenic virus Kaposi's sarcoma-associated herpesvirus (KSHV) and CRISPR/Cas9-mediated targeting of a major viral latent protein. Primary cells can be transformed into malignant status by infection of KSHV, while elimination of the KSHV genome from latent KSHV-infected cells reverses KSHV-transformed primary cells back to a "normal state" by CRISPR/Cas-mediated knockout of viral major latent gene LANA. As a proof of concept, we demonstrated efficient elimination of KSHV episome in KSHV-associated primary effusion lymphoma cells resulting in the induction of apoptosis by liposome-encapsulated CRISPR/Cas9 ribonucleoprotein complexes (Lipo/Cas9-LANAsgRNA). Our work illustrates CRISPR/Cas as a promising technology for eliminating oncogenic viruses from persistently infected cells by taking advantage of the genetic differences between viral and cellular genomes. Compared to traditional antiviral therapy, our study offer an approach for antagonizing human oncogenic virus-related cancers by directly targeting as well as clearing viral genomes., (© 2021 Wiley Periodicals LLC.)
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- 2021
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6. Broad Severe Acute Respiratory Syndrome Coronavirus 2 Cell Tropism and Immunopathology in Lung Tissues From Fatal Coronavirus Disease 2019.
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Ramos da Silva S, Ju E, Meng W, Paniz Mondolfi AE, Dacic S, Green A, Bryce C, Grimes Z, Fowkes M, Sordillo EM, Cordon-Cardo C, Guo H, and Gao SJ
- Subjects
- Adult, Aged, COVID-19 immunology, COVID-19 virology, Female, Humans, Immunity, Innate, Lung cytology, Lung immunology, Lung virology, Male, Middle Aged, Pulmonary Alveoli immunology, Pulmonary Alveoli pathology, Pulmonary Alveoli virology, COVID-19 pathology, Lung pathology, SARS-CoV-2 physiology, Viral Tropism immunology
- Abstract
Background: Coronavirus disease 2019 (COVID-19) patients manifest with pulmonary symptoms reflected by diffuse alveolar damage (DAD), excessive inflammation, and thromboembolism. The mechanisms mediating these processes remain unclear., Methods: We performed multicolor staining for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proteins and lineage markers to define viral tropism and lung pathobiology in 5 autopsy cases., Results: Lung parenchyma showed severe DAD with thromboemboli. Viral infection was found in an extensive range of cells including pneumocyte type II, ciliated, goblet, club-like, and endothelial cells. More than 90% of infiltrating immune cells were positive for viral proteins including macrophages, monocytes, neutrophils, natural killer (NK) cells, B cells, and T cells. Most but not all infected cells were angiotensin-converting enzyme 2 (ACE2) positive. The numbers of infected and ACE2-positive cells are associated with extensive tissue damage. Infected tissues exhibited high levels of inflammatory cells including macrophages, monocytes, neutrophils, and NK cells, and low levels of B cells but abundant T cells consisting of mainly T helper cells, few cytotoxic T cells, and no regulatory T cells. Robust interleukin-6 expression was present in most cells, with or without infection., Conclusions: In fatal COVID-19 lungs, there are broad SARS-CoV-2 cell tropisms, extensive infiltrated innate immune cells, and activation and depletion of adaptive immune cells, contributing to severe tissue damage, thromboemboli, excess inflammation, and compromised immune responses., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)
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- 2021
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7. Gold Nanocluster-Mediated Efficient Delivery of Cas9 Protein through pH-Induced Assembly-Disassembly for Inactivation of Virus Oncogenes.
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Ju E, Li T, Ramos da Silva S, and Gao SJ
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- Female, HeLa Cells, Humans, Hydrogen-Ion Concentration, CRISPR-Associated Protein 9 chemistry, CRISPR-Associated Protein 9 pharmacology, Genes, Viral, Gold chemistry, Gold pharmacology, Metal Nanoparticles chemistry, Metal Nanoparticles therapeutic use, Oncogenes, Tumor Suppressor Protein p53 metabolism, Uterine Cervical Neoplasms drug therapy, Uterine Cervical Neoplasms genetics, Uterine Cervical Neoplasms metabolism, Uterine Cervical Neoplasms virology
- Abstract
The CRISPR/Cas gene editing system has been successfully applied to combating bacteria, cancer, virus, and genetic disorders. While viral vectors have been used for the delivery of the CRISPR/Cas9 system, the time required for insert cloning, and virus packaging and standardization, hinders its efficient use. Additionally, the high molecular weight of the Cas9 endonuclease makes it not easy for packing into the vehicles. Herein we report the self-assembly of gold nanoclusters (AuNCs) with SpCas9 protein (SpCas9-AuNCs) under physiological conditions and the efficient delivery of SpCas9 into the cell nucleus. This assembly process is highly dependent on pH. SpCas9-AuNCs are stable at a higher pH but are disassembled at a lower pH. Significantly, this assembly-disassembly process facilitates the delivery of SpCas9 into cells and the cell nucleus, where the SpCas9 exerts its cleavage function. As a proof-of-concept, the assembled SpCas9-AuNCs nanoparticles are successfully used for efficient knockout of the E6 oncogene, restoring the function of tumor-suppressive protein p53 and inducing apoptosis in cervical cancer cells with little effect on normal human cells. The SpCas9-AuNCs are useful for sgRNA functional validation, sgRNA library screening, and genomic manipulation.
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- 2019
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8. Efficiencies and kinetics of infection in different cell types/lines by African and Asian strains of Zika virus.
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Ramos da Silva S, Cheng F, Huang IC, Jung JU, and Gao SJ
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- Animals, Cell Line, Humans, Zika Virus isolation & purification, Zika Virus Infection virology, Viral Tropism, Virus Replication, Zika Virus growth & development
- Abstract
After recent outbreaks, Zika virus (ZIKV) was linked to severe neurological diseases including Guillain-Barré syndrome in adults and microcephaly in newborns. The severities of pathological manifestations have been associated with different ZIKV strains. To better understand the tropism of ZIKV, we infected 10 human and four nonhuman cell lines (types) with two African (IbH30656 and MR766) and two Asian (PRVABC59 and H/FP/2013) ZIKV strains. Cell susceptibility to ZIKV infection was determined by examining viral titers, synthesis of viral proteins, and replication of positive and negative strands of viral genome. Among nonhuman cell lines, only Vero cells were efficiently infected by ZIKV. Among human cell lines, all were permissive to ZIKV infection. However, 293T and HeLa cells showed differential susceptibility towards African strains. In 293T cells, the NS1 protein was expressed at the high level by African strains but was almost not expressed by Asian strains though there was no obvious difference in viral genome replication, suggesting that the differential susceptibility might be controlled at the stage of viral protein translation. This study provides comprehensive results of the permissiveness of different cell types to both African and Asian ZIKV strains, which might help clarify their different pathogenesis., (© 2018 Wiley Periodicals, Inc.)
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- 2019
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9. FoxO1 Suppresses Kaposi's Sarcoma-Associated Herpesvirus Lytic Replication and Controls Viral Latency.
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Gao R, Li T, Tan B, Ramos da Silva S, Jung JU, Feng P, and Gao SJ
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- Cells, Cultured, Forkhead Box Protein O1 antagonists & inhibitors, Forkhead Box Protein O1 genetics, Humans, Oxidative Stress, Reactive Oxygen Species metabolism, Sarcoma, Kaposi genetics, Forkhead Box Protein O1 metabolism, Herpesvirus 8, Human physiology, Sarcoma, Kaposi metabolism, Sarcoma, Kaposi virology, Virus Activation, Virus Latency, Virus Replication
- Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) has latent and lytic replication phases, both of which contribute to the development of KSHV-induced malignancies. Among the numerous factors identified to regulate the KSHV life cycle, oxidative stress, caused by imbalanced clearing and production of reactive oxygen species (ROS), has been shown to robustly disrupt KSHV latency and induce viral lytic replication. In this study, we identified an important role of the antioxidant defense factor forkhead box protein O1 (FoxO1) in the KSHV life cycle. Either chemical inhibition of the FoxO1 function or knockdown of FoxO1 expression led to an increase in the intracellular ROS level that was subsequently sufficient to disrupt KSHV latency and induce viral lytic reactivation. On the other hand, treatment with N -acetyl-l-cysteine (NAC), an oxygen free radical scavenger, led to a reduction in the FoxO1 inhibition-induced ROS level and, ultimately, the attenuation of KSHV lytic reactivation. These findings reveal that FoxO1 plays a critical role in keeping KSHV latency in check by maintaining the intracellular redox balance. IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with several cancers, including Kaposi's sarcoma (KS). Both the KSHV latent and lytic replication phases are important for the development of KS. Identification of factors regulating the KSHV latent phase-to-lytic phase switch can provide insights into the pathogenesis of KSHV-induced malignancies. In this study, we show that the antioxidant defense factor forkhead box protein O1 (FoxO1) maintains KSHV latency by suppressing viral lytic replication. Inhibition of FoxO1 disrupts KSHV latency and induces viral lytic replication by increasing the intracellular ROS level. Significantly, treatment with an oxygen free radical scavenger, N -acetyl-l-cysteine (NAC), attenuated the FoxO1 inhibition-induced intracellular ROS level and KSHV lytic replication. Our works reveal a critical role of FoxO1 in suppressing KSHV lytic replication, which could be targeted for antiviral therapy., (Copyright © 2019 American Society for Microbiology.)
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- 2019
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10. Suppression of Zika Virus Infection and Replication in Endothelial Cells and Astrocytes by PKA Inhibitor PKI 14-22.
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Cheng F, Ramos da Silva S, Huang IC, Jung JU, and Gao SJ
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- Animals, Astrocytes virology, Chlorocebus aethiops, Endothelial Cells virology, Humans, MAP Kinase Signaling System, Vero Cells, Virus Replication drug effects, Zika Virus Infection drug therapy, Astrocytes drug effects, Carrier Proteins pharmacology, Endothelial Cells drug effects, Intracellular Signaling Peptides and Proteins pharmacology, Peptide Fragments pharmacology, Zika Virus drug effects
- Abstract
The recent outbreak of Zika virus (ZIKV), a reemerging flavivirus, and its associated neurological disorders, such as Guillain-Barré (GB) syndrome and microcephaly, have generated an urgent need to develop effective ZIKV vaccines and therapeutic agents. Here, we used human endothelial cells and astrocytes, both of which represent key cell types for ZIKV infection, to identify potential inhibitors of ZIKV replication. Because several pathways, including the AMP-activated protein kinase (AMPK), protein kinase A (PKA), and mitogen-activated protein kinase (MAPK) signaling pathways, have been reported to play important roles in flavivirus replication, we tested inhibitors and agonists of these pathways for their effects on ZIKV replication. We identified the PKA inhibitor PKI 14-22 (PKI) to be a potent inhibitor of ZIKV replication. PKI effectively suppressed the replication of ZIKV from both the African and Asian/American lineages with a high efficiency and minimal cytotoxicity. While ZIKV infection does not induce PKA activation, endogenous PKA activity is essential for supporting ZIKV replication. Interestingly, in addition to PKA, PKI also inhibited another unknown target(s) to block ZIKV replication. PKI inhibited ZIKV replication at the postentry stage by preferentially affecting negative-sense RNA synthesis as well as viral protein translation. Together, these results have identified a potential inhibitor of ZIKV replication which could be further explored for future therapeutic application. IMPORTANCE There is an urgent need to develop effective vaccines and therapeutic agents against Zika virus (ZIKV) infection, a reemerging flavivirus associated with neurological disorders, including Guillain-Barré (GB) syndrome and microcephaly. By screening for inhibitors of several cellular pathways, we have identified the PKA inhibitor PKI 14-22 (PKI) to be a potent inhibitor of ZIKV replication. We show that PKI effectively suppresses the replication of all ZIKV strains tested with minimal cytotoxicity to human endothelial cells and astrocytes, two key cell types for ZIKV infection. Furthermore, we show that PKI inhibits ZIKV negative-sense RNA synthesis and viral protein translation. This study has identified a potent inhibitor of ZIKV infection which could be further explored for future therapeutic application., (Copyright © 2018 American Society for Microbiology.)
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- 2018
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11. TLR4-Mediated Inflammation Promotes KSHV-Induced Cellular Transformation and Tumorigenesis by Activating the STAT3 Pathway.
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Gruffaz M, Vasan K, Tan B, Ramos da Silva S, and Gao SJ
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- Animals, Carcinogenesis genetics, Cell Proliferation genetics, Cells, Cultured, Female, Humans, Inflammation genetics, Inflammation Mediators physiology, Mice, Mice, Nude, Rats, STAT3 Transcription Factor metabolism, Sarcoma, Kaposi pathology, Sarcoma, Kaposi virology, Signal Transduction genetics, Cell Transformation, Viral genetics, Herpesvirus 8, Human physiology, Inflammation complications, Sarcoma, Kaposi genetics, Toll-Like Receptor 4 physiology
- Abstract
Toll-like receptors (TLR) are conserved immune sensors mediating antimicrobial and antitumoral responses, but recent evidence implicates them in promoting carcinogenesis in certain cancers. Kaposi sarcoma is caused by infection of Kaposi sarcoma-associated herpesvirus (KSHV) and is characterized by uncontrolled neoangiogenesis and inflammation. Here, we show that TLR4 is upregulated in KSHV-infected spindle tumor cells in human Kaposi sarcoma lesions. In a model of KSHV-induced cellular transformation, KSHV upregulated expression of TLR4, its adaptor MyD88, and coreceptors CD14 and MD2. KSHV induction of TLR4 was mediated by multiple viral miRNAs. Importantly, the TLR4 pathway was activated constitutively in KSHV-transformed cells, resulting in chronic induction of IL6, IL1β, and IL18. Accordingly, IL6 mediated constitutive activation of the STAT3 pathway, an essential event for uncontrolled cellular proliferation and transformation. TLR4 stimulation with lipopolysaccharides or live bacteria enhanced tumorigenesis while TLR4 antagonist CLI095 inhibited it. These results highlight an essential role of the TLR4 pathway and chronic inflammation in KSHV-induced tumorigenesis, which helps explain why HIV-infected patients, who frequently suffer from opportunistic bacterial infections and metabolic complications, frequently develop Kaposi sarcoma. Cancer Res; 77(24); 7094-108. ©2017 AACR ., (©2017 American Association for Cancer Research.)
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- 2017
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12. A Critical Role of Glutamine and Asparagine γ-Nitrogen in Nucleotide Biosynthesis in Cancer Cells Hijacked by an Oncogenic Virus.
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Zhu Y, Li T, Ramos da Silva S, Lee JJ, Lu C, Eoh H, Jung JU, and Gao SJ
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- Asparagine pharmacology, Aspartate Aminotransferases genetics, Aspartic Acid pharmacology, Glutamate Dehydrogenase genetics, Glutamic Acid pharmacology, Glutaminase genetics, Glutamine deficiency, Humans, Metabolic Networks and Pathways, Neoplasms physiopathology, Nitrogen metabolism, Asparagine metabolism, Cell Proliferation drug effects, Glutamine metabolism, Herpesvirus 8, Human physiology, Neoplasms pathology, Neoplasms virology, Nucleotides biosynthesis
- Abstract
While glutamine is a nonessential amino acid that can be synthesized from glucose, some cancer cells primarily depend on glutamine for their growth, proliferation, and survival. Numerous types of cancer also depend on asparagine for cell proliferation. The underlying mechanisms of the glutamine and asparagine requirement in cancer cells in different contexts remain unclear. In this study, we show that the oncogenic virus Kaposi's sarcoma-associated herpesvirus (KSHV) accelerates the glutamine metabolism of glucose-independent proliferation of cancer cells by upregulating the expression of numerous critical enzymes, including glutaminase 2 (GLS2), glutamate dehydrogenase 1 (GLUD1), and glutamic-oxaloacetic transaminase 2 (GOT2), to support cell proliferation. Surprisingly, cell crisis is rescued only completely by supplementation with asparagine but minimally by supplementation with α-ketoglutarate, aspartate, or glutamate upon glutamine deprivation, implying an essential role of γ-nitrogen in glutamine and asparagine for cell proliferation. Specifically, glutamine and asparagine provide the critical γ-nitrogen for purine and pyrimidine biosynthesis, as knockdown of four rate-limiting enzymes in the pathways, including carbamoylphosphate synthetase 2 (CAD), phosphoribosyl pyrophosphate amidotransferase (PPAT), and phosphoribosyl pyrophosphate synthetases 1 and 2 (PRPS1 and PRPS2, respectively), suppresses cell proliferation. These findings indicate that glutamine and asparagine are shunted to the biosynthesis of nucleotides and nonessential amino acids from the tricarboxylic acid (TCA) cycle to support the anabolic proliferation of KSHV-transformed cells. Our results illustrate a novel mechanism by which an oncogenic virus hijacks a metabolic pathway for cell proliferation and imply potential therapeutic applications in specific types of cancer that depend on this pathway. IMPORTANCE We have previously found that Kaposi's sarcoma-associated herpesvirus (KSHV) can efficiently infect and transform primary mesenchymal stem cells; however, the metabolic pathways supporting the anabolic proliferation of KSHV-transformed cells remain unknown. Glutamine and asparagine are essential for supporting the growth, proliferation, and survival of some cancer cells. In this study, we have found that KSHV accelerates glutamine metabolism by upregulating numerous critical metabolic enzymes. Unlike most cancer cells that primarily utilize glutamine and asparagine to replenish the TCA cycle, KSHV-transformed cells depend on glutamine and asparagine for providing γ-nitrogen for purine and pyrimidine biosynthesis. We identified four rate-limiting enzymes in this pathway that are essential for the proliferation of KSHV-transformed cells. Our results demonstrate a novel mechanism by which an oncogenic virus hijacks a metabolic pathway for cell proliferation and imply potential therapeutic applications in specific types of cancer that depend on this pathway., (Copyright © 2017 Zhu et al.)
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- 2017
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13. SIRT1 and AMPK pathways are essential for the proliferation and survival of primary effusion lymphoma cells.
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He M, Tan B, Vasan K, Yuan H, Cheng F, Ramos da Silva S, Lu C, and Gao SJ
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- AMP-Activated Protein Kinases metabolism, Animals, Antineoplastic Agents pharmacology, Apoptosis physiology, Benzamides pharmacology, Cell Cycle Checkpoints physiology, Cell Proliferation physiology, Cell Survival physiology, Dose-Response Relationship, Drug, Gene Knockdown Techniques, Lymphoma, Primary Effusion enzymology, MAP Kinase Signaling System physiology, Mice, Inbred NOD, Mice, SCID, Phosphorylation physiology, Sirtuin 1 antagonists & inhibitors, AMP-Activated Protein Kinases physiology, Lymphoma, Primary Effusion physiopathology, Sirtuin 1 physiology
- Abstract
Primary effusion lymphoma (PEL) is a rare and aggressive B-cell lymphoma with a dismal prognosis caused by infection of Kaposi's sarcoma-associated herpesvirus. Despite the findings that numerous viral genes and cellular pathways are essential for the proliferation and survival of PEL cells, there is currently no effective therapeutic treatment for PEL. Here, we report that the metabolic sensor SIRT1 is functionally required for sustaining the proliferation and survival of PEL cells. Knockdown of SIRT1 with specific shRNAs or inhibition of SIRT1 with an inhibitor (tenovin-6) induced cell cycle arrest and apoptosis in PEL cells. We detected high levels of AMPK activation in PEL cells, reflected in AMPKα1 phosphorylation at T174. Knockdown or inhibition of SIRT1 reduced AMPK activation, indicating that SIRT1 was required for AMPK activation. Interestingly, knockdown of AMPK with specific shRNAs or inhibition of AMPK with the inhibitor compound C recapitulated the phenotype of SIRT1, and induced cell cycle arrest and apoptosis, whereas overexpression of a constitutively active AMPK construct rescued the cytotoxic effect of SIRT1 knockdown. Remarkably, treatment with tenovin-6 effectively inhibited the initiation and progression of PEL, and significantly extended the survival of mice in a murine PEL model. Taken together, these results illustrate that the SIRT1-AMPK axis is essential for maintaining the proliferation and survival of PEL and identify SIRT1 and AMPK as potential therapeutic targets, and tenovin-6 as a candidate therapeutic agent for PEL patients. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd., (Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)
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- 2017
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14. First Published Study with Embryonated Hen Egg Infected with Zika Virus Is Dated from 1952.
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Ramos da Silva S
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- Animals, Chickens virology, Female, History, 20th Century, Ovum virology, Peer Review, Research, Zika Virus Infection virology, Zika Virus pathogenicity, Zika Virus Infection history
- Published
- 2017
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15. Zika virus update II: Recent development of animal models-Proofs of association with human pathogenesis.
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Ramos da Silva S and Gao SJ
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- Animals, Female, Humans, Macaca mulatta, Mice, Pregnancy, Zika Virus Infection complications, Disease Models, Animal, Infectious Disease Transmission, Vertical, Pregnancy Complications, Infectious virology, Zika Virus pathogenicity, Zika Virus Infection transmission, Zika Virus Infection virology
- Abstract
Three recent studies in pregnant mice and one ongoing study in rhesus macaques evaluating the effect of ZIKV infection have provided important information about maternal-fetus transmission and ZIKV-related pathogenesis, confirming a causal role of ZIKV in neurological problems observed in humans. Here, we present an update of these works published in the past few weeks. J. Med. Virol. 88:1657-1658, 2016. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)
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- 2016
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16. Zika virus: An update on epidemiology, pathology, molecular biology, and animal model.
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Ramos da Silva S and Gao SJ
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- Aedes virology, Animals, Brazil epidemiology, Disease Outbreaks, Humans, Insect Vectors virology, Mice, Microcephaly virology, Micronesia epidemiology, Nervous System Diseases virology, Primates, Zika Virus Infection virology, Disease Models, Animal, Zika Virus genetics, Zika Virus Infection epidemiology, Zika Virus Infection physiopathology
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Zika virus (ZIKV) was first described in 1947, and became a health emergency problem in 2016 when its association with fetal microcephaly cases was confirmed by Centers for Disease Control and Prevention (CDC) in the United States. To date, ZIKV infection has been documented in 66 countries. ZIKV is recognized as a neurotropic virus and numerous diseases manifested in multiple neurological disorders have been described, mainly in countries that have been exposed to ZIKV after the 2007 outbreak in the Federated States of Micronesia. The most dramatic consequence of ZIKV infection documented is the abrupt increase in fetal microcephaly cases in Brazil. Here, we present an update of the published research progress in the past few months. J. Med. Virol. 88:1291-1296, 2016. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)
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- 2016
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17. An Oncogenic Virus Promotes Cell Survival and Cellular Transformation by Suppressing Glycolysis.
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Zhu Y, Ramos da Silva S, He M, Liang Q, Lu C, Feng P, Jung JU, and Gao SJ
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- Animals, Blotting, Western, Cell Line, Tumor, Cell Survival, Disease Models, Animal, Flow Cytometry, Fluorescent Antibody Technique, Gene Knockdown Techniques, Glycolysis physiology, Herpesvirus 8, Human metabolism, Humans, Lymphoma, Primary Effusion metabolism, Lymphoma, Primary Effusion virology, Microscopy, Confocal, Polymerase Chain Reaction, Rats, Adaptation, Physiological physiology, Cell Transformation, Viral physiology, Herpesviridae Infections metabolism
- Abstract
Aerobic glycolysis is essential for supporting the fast growth of a variety of cancers. However, its role in the survival of cancer cells under stress conditions is unclear. We have previously reported an efficient model of gammaherpesvirus Kaposi's sarcoma-associated herpesvirus (KSHV)-induced cellular transformation of rat primary mesenchymal stem cells. KSHV-transformed cells efficiently induce tumors in nude mice with pathological features reminiscent of Kaposi's sarcoma tumors. Here, we report that KSHV promotes cell survival and cellular transformation by suppressing aerobic glycolysis and oxidative phosphorylation under nutrient stress. Specifically, KSHV microRNAs and vFLIP suppress glycolysis by activating the NF-κB pathway to downregulate glucose transporters GLUT1 and GLUT3. While overexpression of the transporters rescues the glycolytic activity, it induces apoptosis and reduces colony formation efficiency in softagar under glucose deprivation. Mechanistically, GLUT1 and GLUT3 inhibit constitutive activation of the AKT and NF-κB pro-survival pathways. Strikingly, GLUT1 and GLUT3 are significantly downregulated in KSHV-infected cells in human KS tumors. Furthermore, we have detected reduced levels of aerobic glycolysis in several KSHV-infected primary effusion lymphoma cell lines compared to a Burkitt's lymphoma cell line BJAB, and KSHV infection of BJAB cells reduced aerobic glycolysis. These results reveal a novel mechanism by which an oncogenic virus regulates a key metabolic pathway to adapt to stress in tumor microenvironment, and illustrate the importance of fine-tuning the metabolic pathways for sustaining the proliferation and survival of cancer cells, particularly under stress conditions.
- Published
- 2016
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18. Human gammaherpesviruses viraemia in HIV infected patients.
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Ferraz da Silva AP, Giron LB, Ramos da Silva S, Naime Barbosa A, Almeida RA, and Elgui de Oliveira D
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- Adolescent, Adult, Aged, Cohort Studies, Enzyme-Linked Immunosorbent Assay, Female, Herpesvirus 4, Human, Herpesvirus 8, Human, Humans, Longitudinal Studies, Male, Middle Aged, Real-Time Polymerase Chain Reaction, Young Adult, Coinfection, HIV Infections complications, HIV Infections virology, Herpesviridae Infections complications, Herpesviridae Infections virology, Viremia complications
- Abstract
Background: The Epstein-Barr virus (EBV) and Kaposi's sarcoma associated herpesvirus (KSHV) are consistently associated with lymphoproliferative diseases and cancers in humans, notably in patients with HIV., Aims: Our aim was to evaluate whether EBV and/or KSHV viral loads regularly assessed in peripheral blood mononuclear cells (PBMC) correlate with clinical or laboratorial parameters retrieved for patients living with HIV., Methods: This was a longitudinal study with a cohort of 157 HIV positive patients attending an academic HIV outpatient clinic in São Paulo State, Brazil. For each patient, up to four blood samples were collected over a 1 year clinical follow-up: on enrolment into the study, and after 4, 8 and 12 months. Total DNA was extracted from PBMC, and EBV and KSHV viral loads were assessed by real time quantitative PCR., Results: Higher viral loads for EBV were significantly associated with high HIV viraemia, a greater number of circulating T CD8+ cells and lack of virological response to the antiretroviral treatment. KSHV viral load was undetectable in virtually all samples., Conclusions: EBV viral load in PBMC correlated with the number of circulating T CD8+ lymphocytes and the response to the antiretroviral therapy in HIV infected patients. In contrast, KSHV was undetectable in PBMC, presumably an effect of the antiretroviral treatment. Therefore, either KSHV infection in the population studied was absent or viral load in PBMC was beyond the analytical limit of the assay., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)
- Published
- 2015
- Full Text
- View/download PDF
19. Viral cyclin promotes KSHV-induced cellular transformation and tumorigenesis by overriding contact inhibition.
- Author
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Jones T, Ramos da Silva S, Bedolla R, Ye F, Zhou F, and Gao SJ
- Subjects
- Animals, Apoptosis, Carcinogenesis pathology, Cell Cycle, Cell Line, Tumor, Cell Proliferation, Cell Transformation, Neoplastic, Cellular Senescence, Cyclin D2 genetics, Cyclin-Dependent Kinase Inhibitor p27 genetics, Mice, Nude, Mutation, Phosphorylation, Viral Proteins genetics, Carcinogenesis genetics, Contact Inhibition physiology, Cyclin D2 metabolism, Herpesvirus 8, Human physiology, Viral Proteins metabolism
- Abstract
Kaposi sarcoma-associated herpesvirus (KSHV) is a tumor virus encoding several proto-oncogenes. However, the roles of these viral genes in KSHV-induced tumorigenesis have not been defined. In this study, we used a recently developed model of KSHV-induced cellular transformation and tumorigenesis combining with a reverse genetic system to examine the role of a KSHV latent gene vCyclin (ORF72), a cellular Cyclin D2 homolog, in KSHV-induced oncogenesis. Deletion of vCyclin did not affect cell proliferation and cell cycle progression at a low-density condition, when cells were at an active proliferation state. However, vCyclin mutant cells were contact-inhibited and arrested at G 1 phase at a high-density condition. As a result, vCyclin mutant cells formed less and smaller colonies in soft agar assay. Nude mice inoculated with vCyclin mutant cells had reduced tumor incidence and extended tumor latency and survival compared with mice inoculated with wild-type (WT) virus-infected cells. WT but not mutant virus effectively induced Cyclin-dependent kinase inhibitor p27/Kip1 Ser10 phosphorylation and cytoplasmic relocalization. shRNA knockdown of p27 released the blockage of the mutant cells from cell cycle arrest at G 1 phase at a high-density condition. Together, these results indicate that vCyclin primarily functions to enhance cellular transformation and tumorigenesis by promoting cell cycle progression and cell proliferation at a contact-inhibited condition.
- Published
- 2014
- Full Text
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20. Impact of Epstein-Barr virus load, virus genotype, and frequency of the 30 bp deletion in the viral BNLF-1 gene in patients harboring the human immunodeficiency virus.
- Author
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Giron LB, Ramos da Silva S, Barbosa AN, Monteiro de Barros Almeida RA, Rosário de Souza Ld, and Elgui de Oliveira D
- Subjects
- Antiretroviral Therapy, Highly Active, CD4 Lymphocyte Count, Female, Humans, Leukocytes, Mononuclear virology, Male, Viral Load, Coinfection, Epstein-Barr Virus Infections virology, Genotype, HIV Infections drug therapy, HIV Infections immunology, HIV Infections virology, Herpesvirus 4, Human genetics, Sequence Deletion, Viral Matrix Proteins genetics
- Abstract
Patients infected with the human immunodeficiency virus (HIV) are at higher risk of developing Epstein-Barr Virus (EBV)-associated lymphomas. The usefulness of monitoring EBV in peripheral blood mononuclear cells (PBMCs) of patients infected with HIV has not been established. The aim of this study was to evaluate the EBV viral load in PBMCs, the frequency of viral genotypes, and the presence of the 30-bp deletion in the BNLF-1 gene. DNA samples from 156 patients attending the HIV/AIDS Day Clinic at Botucatu School of Medicine, Sao Paulo State University were evaluated. The EBV viral load was detectable by real time PCR in 123/156 (78.8%) cases and was higher in patients not receiving antiretroviral treatment or under therapeutic failure than in patients under successful highly active antiretroviral therapy (HAART) (P = 0.0076). Overall, the profile of patients with high EBV viral load included elevated HIV viremia (P = 0.0005), longer time of HIV diagnosis (P = 0.0026), and increased levels of T CD8 (+) lymphocytes (P = 0.0159). The successful amplification of the EBNA-2 gene by nested-PCR was achieved in 95 of 123 (77.2%) cases, of which 75.8% were EBV-1, 9.5% EBV-2, and 14.7% were co-infected with both EBV-1 and -2. The analysis of the BNLF-1 gene was possible in 99 of 123 (80.5%) cases, of which 50.5% had the 30-bp deletion. EBV-1 was more common than EBV-2, which may reflect the fact that the cohort was predominantly Caucasian and heterosexual., (© 2013 Wiley Periodicals, Inc.)
- Published
- 2013
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- View/download PDF
21. KSHV genotypes A and C are more frequent in Kaposi sarcoma lesions from Brazilian patients with and without HIV infection, respectively.
- Author
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Ramos da Silva S, Ferraz da Silva AP, Bacchi MM, Bacchi CE, and Elgui de Oliveira D
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Base Sequence, Brazil, Female, Genotype, Herpesvirus 8, Human genetics, Humans, Male, Middle Aged, Molecular Sequence Data, Phylogeny, Young Adult, HIV Infections virology, Herpesvirus 8, Human classification, Sarcoma, Kaposi virology
- Abstract
The present study aimed to evaluate the frequency of KSHV genotypes isolated from Kaposi sarcoma (KS) lesions in patients from Brazil. Fifty KS cases were evaluated. The most frequently detected viral genotypes were A (50.0%) and C (48.0%); the B genotype was isolated only in one case (2.0%). Noteworthy, there was a significant predominance of A genotypes in KS lesions from HIV-positive patients, whereas C genotypes were found mostly in the HIV-negative setting. This finding supports the hypothesis that distinct KSHV genotypes have a non-random distribution in KS, which might be attributable to unique biological properties., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)
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- 2011
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22. Relationship (or its lack) between population and a water and sanitation service: a study of users' perception in Vitória (ES) Brazil.
- Author
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Ramos da Silva S, Heller L, de Campos Valadares J, and Cairncross S
- Subjects
- Brazil, Humans, Public Health, Sanitation, Urban Population, Water Supply
- Abstract
The objective of this paper is to identify and analyse the perception of groups of dwellers of Vitória, Espírito Santo, Brazil, regarding their relationship with the water and sanitation service and aspects of water handling. Participants living in four distinct urban districts of the capital city were interviewed in their own houses and the Discourse of the Collective Subject approach was employed to order the data so obtained. The testimonies revealed the health risk to which individuals were exposed by virtue of: (i) inadequate knowledge concerning the water supply offered, (ii) lack of stimulus to exert their citizens' rights and obligations in relation to the water provided for their consumption and (iii) poor channels of communication between the community, the water and sanitation service and the local public health authority. The study concluded that there is a need to rethink the forms of information provided to the population that are presently adopted by these institutions.
- Published
- 2010
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23. Human bcl-2 expression, cleaved caspase-3, and KSHV LANA-1 in Kaposi sarcoma lesions.
- Author
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Ramos da Silva S, Bacchi MM, Bacchi CE, and Elgui de Oliveira D
- Subjects
- AIDS-Related Opportunistic Infections pathology, AIDS-Related Opportunistic Infections virology, Adolescent, Adult, Aged, Aged, 80 and over, Apoptosis, Brazil, DNA, Viral analysis, Female, Fluorescent Antibody Technique, Indirect, Herpesvirus 8, Human genetics, Herpesvirus 8, Human isolation & purification, Humans, Male, Middle Aged, Sarcoma, Kaposi pathology, Sarcoma, Kaposi virology, Skin Neoplasms pathology, Skin Neoplasms virology, AIDS-Related Opportunistic Infections metabolism, Antigens, Viral metabolism, Caspase 3 metabolism, Nuclear Proteins metabolism, Oncogene Proteins metabolism, Proto-Oncogene Proteins c-bcl-2 metabolism, Sarcoma, Kaposi metabolism, Skin Neoplasms metabolism, Viral Proteins metabolism
- Abstract
We aimed to evaluate the frequency of Kaposi sarcoma (KS)-associated herpesvirus (KSHV) infection in KS lesions in patients from Brazil. In addition, expression of human bcl-2, cleaved caspase-3, and KSHV latency-associated nuclear antigen (LANA)-1 in tumors was evaluated using immunohistochemical analysis. We studied 64 KS cases, classified as follows: classical, 20 (31%); iatrogenic, 2 (3%); AIDS-associated, 25 (39%); and not otherwise specified (lack of information about HIV status), 17 (27%). KSHV was detected by polymerase chain reaction (PCR) in 61 cases (95%); 40 cases (63%) were KSHV+ by PCR and immunohistochemical analysis for LANA-1. Immunoexpression of bcl-2 was detected in 47 cases (73%). Only a few cells in 15 cases (23%) of KS had demonstrable immunostaining for cleaved caspase-3. These results further support the association of KSHV with all KS forms. Cleaved caspase-3 in KS tumors was infrequent, which may reflect the inhibition of apoptosis owing to bcl-2 overexpression observed in the majority of KS tumors.
- Published
- 2007
- Full Text
- View/download PDF
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