How Kaposi's sarcoma-associated herpesvirus stably transforms peripheral B cells towards lymphomagenesis.

Primary effusion lymphomas (PELs) are causally associated with Kaposi's sarcoma-associated herpesvirus (KSHV) and 86% of PELs are coinfected with Epstein-Barr virus (EBV). Understanding how PELs develop has been impaired by the difficulty of infecting B cells with KSHV in vitro, and the inability of KSHV to transform them. We show that EBV supports an optimal coinfection of 2.5% of peripheral B cells by KSHV. This coinfection requires 1 or more transforming genes of EBV but not entry into KSHV's lytic cycle. We demonstrate that dually infected B cells are stably transformed in vitro and show that while both viruses can be maintained, different cells exhibit distinct, transformed properties. Transformed cells that grow to predominate in a culture express increased levels of most KSHV genes and differentially express a subset of cellular genes, as do bona fide PEL cells. These dually infected peripheral B cells are thus both stably transformed and allow in vitro molecular dissection of early steps in the progression to lymphomagenesis.

Primary Focal Therapy for Localized Prostate Cancer: A Review of the Literature.

This article describes the available focal therapy options for primary treatment of localized PCa, along with their respective outcomes, drawbacks, and applicability.

An EBNA3C-deleted Epstein-Barr virus (EBV) mutant causes B-cell lymphomas with delayed onset in a cord blood-humanized mouse model.

EBV causes human B-cell lymphomas and transforms B cells in vitro. EBNA3C, an EBV protein expressed in latently-infected cells, is required for EBV transformation of B cells in vitro. While EBNA3C undoubtedly plays a key role in allowing EBV to successfully infect B cells, many EBV+ lymphomas do not express this protein, suggesting that cellular mutations and/or signaling pathways may obviate the need for EBNA3C in vivo under certain conditions. EBNA3C collaborates with EBNA3A to repress expression of the CDKN2A-encoded tumor suppressors, p16 and p14, and EBNA3C-deleted EBV transforms B cells containing a p16 germline mutation in vitro. Here we have examined the phenotype of an EBNAC-deleted virus (Δ3C EBV) in a cord blood-humanized mouse model (CBH). We found that the Δ3C virus induced fewer lymphomas (occurring with a delayed onset) in comparison to the wild-type (WT) control virus, although a subset (10/26) of Δ3C-infected CBH mice eventually developed invasive diffuse large B cell lymphomas with type III latency. Both WT and Δ3C viruses induced B-cell lymphomas with restricted B-cell populations and heterogeneous T-cell infiltration. In comparison to WT-infected tumors, Δ3C-infected tumors had greatly increased p16 levels, and RNA-seq analysis revealed a decrease in E2F target gene expression. However, we found that Δ3C-infected tumors expressed c-Myc and cyclin E at similar levels compared to WT-infected tumors, allowing cells to at least partially bypass p16-mediated cell cycle inhibition. The anti-apoptotic proteins, BCL2 and IRF4, were expressed in Δ3C-infected tumors, likely helping cells avoid c-Myc-induced apoptosis. Unexpectedly, Δ3C-infected tumors had increased T-cell infiltration, increased expression of T-cell chemokines (CCL5, CCL20 and CCL22) and enhanced type I interferon response in comparison to WT tumors. Together, these results reveal that EBNA3C contributes to, but is not essential for, EBV-induced lymphomagenesis in CBH mice, and suggest potentially important immunologic roles of EBNA3C in vivo.

Epstein-Barr virus microRNAs reduce immune surveillance by virus-specific CD8+ T cells.

Infection with Epstein-Barr virus (EBV) affects most humans worldwide and persists life-long in the presence of robust virus-specific T-cell responses. In both immunocompromised and some immunocompetent people, EBV causes several cancers and lymphoproliferative diseases. EBV transforms B cells in vitro and encodes at least 44 microRNAs (miRNAs), most of which are expressed in EBV-transformed B cells, but their functions are largely unknown. Recently, we showed that EBV miRNAs inhibit CD4+ T-cell responses to infected B cells by targeting IL-12, MHC class II, and lysosomal proteases. Here we investigated whether EBV miRNAs also counteract surveillance by CD8+ T cells. We have found that EBV miRNAs strongly inhibit recognition and killing of infected B cells by EBV-specific CD8+ T cells through multiple mechanisms. EBV miRNAs directly target the peptide transporter subunit TAP2 and reduce levels of the TAP1 subunit, MHC class I molecules, and EBNA1, a protein expressed in most forms of EBV latency and a target of EBV-specific CD8+ T cells. Moreover, miRNA-mediated down-regulation of the cytokine IL-12 decreases the recognition of infected cells by EBV-specific CD8+ T cells. Thus, EBV miRNAs use multiple, distinct pathways, allowing the virus to evade surveillance not only by CD4+ but also by antiviral CD8+ T cells.

Selecting patients for magnetic resonance imaging cognitive versus ultrasound fusion biopsy of the prostate: A within-patient comparison.

Objectives: To compare overall agreement between magnetic resonance imaging (MRI)-ultrasound (US) fusion biopsy (FB) and MRI cognitive fusion biopsy (CB) of the prostate and determine which factors affect agreement for prostate cancer (PCa) who underwent both modalities in a prospective within-patient protocol. Patients and Methods: From August 2017 to January 2021, patients with at least one Prostate Imaging Reporting & Data System (PI-RADS) 3 or higher lesion on multiparametric MRI underwent transrectal FB and CB in a prospective within-patient protocol. CB was performed for each region of interest (ROI), followed by FB, followed by standard 12 core biopsy. Patients who were not on active surveillance were analysed. The primary endpoint was agreement for any PCa detection. McNemar's test and kappa statistic were used to analyse agreement. Chi-square test, Fisher's exact test and Wilcoxon rank sum test were used to analyse disagreement across clinical and MRI spatial variables. A multivariable generalized mixed-effect model was used to compare the interaction between select variables and fusion modality. Statistics were performed using SAS and R. Results: Ninety patients and 98 lesions were included in the analysis. There was moderate agreement between FB and CB (k = 0.715). McNemar's test was insignificant (p = 0.285). Anterior location was the only variable associated with a significant variation in agreement, which was 70% for anterior lesions versus 89.7% for non-anterior lesions (p = 0.035). Discordance did not vary significantly across other variables. In a mixed-effect model, the interaction between anterior location and use of FB was insignificant (p = 0.411). Conclusion: In a within-patient protocol of patients not on active surveillance, FB and CB performed similarly for PCa detection and with moderate agreement. Anterior location was associated with significantly higher disagreement, whereas other patient and lesion characteristics were not. Additional studies are needed to determine optimal biopsy technique for sampling anterior ROI.

How Epstein-Barr Virus and Kaposi's Sarcoma-Associated Herpesvirus Are Maintained Together to Transform the Same B-Cell.

Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) independently cause human cancers, and both are maintained as plasmids in tumor cells. They differ, however, in their mechanisms of segregation; EBV partitions its genomes quasi-faithfully, while KSHV often clusters its genomes and partitions them randomly. Both viruses can infect the same B-cell to transform it in vitro and to cause primary effusion lymphomas (PELs) in vivo. We have developed simulations based on our measurements of these replicons in B-cells transformed in vitro to elucidate the synthesis and partitioning of these two viral genomes when in the same cell. These simulations successfully capture the biology of EBV and KSHV in PELs. They have revealed that EBV and KSHV replicate and partition independently, that they both contribute selective advantages to their host cell, and that KSHV pays a penalty to cluster its genomes.

The Epstein-Barr Virus Oncogene EBNA1 Suppresses Natural Killer Cell Responses and Apoptosis Early after Infection of Peripheral B Cells.

The innate immune system serves as frontline defense against pathogens, such as bacteria and viruses. Natural killer (NK) cells are a part of innate immunity and can both secrete cytokines and directly target cells for lysis. NK cells express several cell surface receptors, including NKG2D, which bind multiple ligands. People with deficiencies in NK cells are often susceptible to uncontrolled infection by herpesviruses, such as Epstein-Barr virus (EBV). Infection with EBV stimulates both innate and adaptive immunity, yet the virus establishes lifelong latent infection in memory B cells. We show that the EBV oncogene EBNA1, previously known to be necessary for maintaining EBV genomes in latently infected cells, also plays an important role in suppressing NK cell responses and cell death in newly infected cells. EBNA1 does so by downregulating the NKG2D ligands ULBP1 and ULBP5 and modulating expression of c-Myc. B cells infected with a derivative of EBV that lacks EBNA1 are more susceptible to NK cell-mediated killing and show increased levels of apoptosis. Thus, EBNA1 performs a previously unappreciated role in reducing immune response and programmed cell death after EBV infection, helping infected cells avoid immune surveillance and apoptosis and thus persist for the lifetime of the host. IMPORTANCE Epstein-Barr virus (EBV) is a ubiquitous human pathogen, infecting up to 95% of the world's adult population. Initial infection with EBV can cause infectious mononucleosis. EBV is also linked to several human malignancies, including lymphomas and carcinomas. Although infection by EBV alerts the immune system and causes an immune response, the virus persists for life in memory B cells. We show that the EBV protein EBNA1 can downregulate several components of the innate immune system linked to natural killer (NK) cells. This downregulation of NK cell activity translates to lower killing of EBV-infected cells and is likely one way that EBV escapes immune surveillance after infection. Additionally, we show that EBNA1 reduces apoptosis in newly infected B cells, allowing more of these cells to survive. Taken together, our findings uncover new functions of EBNA1 and provide insights into viral strategies to survive the initial immune response postinfection.

Epstein-Barr viral miRNAs inhibit antiviral CD4+ T cell responses targeting IL-12 and peptide processing.

Epstein-Barr virus (EBV) is a tumor virus that establishes lifelong infection in most of humanity, despite eliciting strong and stable virus-specific immune responses. EBV encodes at least 44 miRNAs, most of them with unknown function. Here, we show that multiple EBV miRNAs modulate immune recognition of recently infected primary B cells, EBV's natural target cells. EBV miRNAs collectively and specifically suppress release of proinflammatory cytokines such as IL-12, repress differentiation of naive CD4(+) T cells to Th1 cells, interfere with peptide processing and presentation on HLA class II, and thus reduce activation of cytotoxic EBV-specific CD4(+) effector T cells and killing of infected B cells. Our findings identify a previously unknown viral strategy of immune evasion. By rapidly expressing multiple miRNAs, which are themselves nonimmunogenic, EBV counteracts recognition by CD4(+) T cells and establishes a program of reduced immunogenicity in recently infected B cells, allowing the virus to express viral proteins required for establishment of life-long infection.