Biology subjects

Barry, A. P.

Publications and source records attributed to Barry, A. P..

5 recordsLinked to original sources

bioRxiv2025

Dissecting Epstein-Barr Virus Dependence Across Diverse Infected Cell Models

Epstein-Barr virus (EBV) is maintained clonally in a wide array of tumors and cells of lymphoproliferative disorders, yet the degree to which these infected cells continuously depend on EBV remains unresolved. To directly assess EBV dependence, we used two complementary Cas9-based viral eviction strategies: 1) targeting EBNA1 to promote episome dilution during cell division, and 2) targeting repetitive viral genomic regions to rapidly degrade EBV episomes. Using these approaches, we evaluated EBV-loss sensitivity across newly-derived, phenotypically diverse EBV-positive Burkitt lymphoma lines. We also evaluated cell lines from patients with EBV-associated T/NK and epithelial malignancies. We included the Burkitt Lymphoma cell line, Akata-GFP, as our EBV-loss-tolerant control and a lymphoblastoid cell line as our EBV-loss-sensitive control. We observed EBV-loss sensitivity in all the EBV-positive Burkitt Lymphoma cell lines and the chronic active EBV disease cell line. In contrast, the EBV-positive gastric adenocarcinoma lines were markedly less sensitive to EBV loss. EBV latency type did not predict EBV dependence, indicating that viral gene expression programs alone do not dictate reliance on the virus. These findings demonstrate that EBV dependence is prevalent across multiple EBV-associated disease models and is especially pronounced in early-state or newly derived lymphoid malignancies. AUTHOR SUMMARYEpstein-Barr virus (EBV) infects most people worldwide and is linked to many malignancies. Although EBV is present in cancer cells, it is unclear whether these cells require the virus to survive. To answer this question, we used CRISPR/Cas9-based methods to remove EBV from infected cells. Using these tools, we studied many different EBV-positive cell lines, including new Burkitt lymphoma cell lines. We found that most EBV-positive lymphoid cells required EBV for growth. In contrast, EBV-positive gastric cells were more tolerant of viral loss. These results show that many EBV-associated malignancies, especially early or newly established diseases, rely on EBV to survive.

microbiology↗

bioRxiv2025

HIV-associated non-Hodgkin lymphoma tumor-microenvironment axes differ by EBV status across cellular origins

Non-Hodgkin Lymphoma (NHL) is the main cancer-related mortality for people living with HIV (PLWH). NHL genetic and molecular classifications have been intensely studied and correlated with clinical outcomes, but critical unanswered questions relevant to malignancy persist. For example, tumors positive for Epstein-Barr virus (EBV) are aggressive and account for 30-50% of HIV-associated NHLs, yet insights on the nature of EBV in NHL pathogenesis or potential therapeutic vulnerabilities have been limited. Here, we examined HIV-associated NHLs stratified by histopathologic classification, cell of origin (COO), molecular subtype, and EBV status using genome-wide spatial transcriptomic analyses. Tumor tissues in EBV+ HIV-NHLs displayed enriched expression of mitochondrial respiration and purine metabolism signatures versus EBV- tumors. Immune infiltration of EBV+ tumors was limited, and immune and stromal regions of EBV+ HIV-NHLs displayed upregulation of the gene for the iron exporter ferroportin (SLC40A1), indicating immunosuppressive macrophage polarization. An immunosuppressive SPP1-CD44 axis and oncogenic GAS6-AXL interaction between tumor and stroma were specifically predicted for EBV+ HIV-NHLs with plasmablastic features. Tumor microenvironment (TME) similarities to secondary lymphoid tissues such as inverse CXCL12-CXCL13 gradients and evidence of matching between tumor B cell phenotypes and reticular cell signatures were also observed. Finally, we developed a simple yet flexible approach to quantify expression gradients and cell proximity to annotated regions. Thus, this study highlights potential avenues for NHL therapy tailored by EBV status and provides a unique resource to examine tumor-TME interactions in the HIV-immunocompromised context. Key PointsO_LISpatial transcriptomic landscapes resolve cell-of-origin- and EBV-associated HIV-NHL heterogeneity including immunosuppressive myeloid responses to EBV+ tumors C_LIO_LISpatial gradients including CXCL12 and CXCL13 indicate that tumor-stromal interactions mimic lymphoid tissue organization and depend on B cell development stage C_LIO_LIDevelopment of a direction-agnostic method to calculate spatial expression gradients relative to annotated tissue and cell types of interest C_LIO_LIPredicted pharmacologic vulnerabilities in clinical samples are replicated in vitro and confirmed by small molecule screening C_LI

cancer biology↗

bioRxiv2025

Single-Cell Profiling of HDAC Inhibitor-Induced EBV Lytic Heterogeneity Defines Abortive and Refractory States in B Lymphoblasts

Epstein-Barr virus (EBV) is associated with multiple malignancies including Burkitt lymphoma (BL), Hodgkins lymphomas, nasopharyngeal carcinomas (NPC), and gastric cancers. Canonically, EBV positive tumors display latent gene expression programs that are difficult to target pharmacologically. To overcome this hurdle, lytic reactivation therapies have been developed based on HDAC inhibition with limited mechanistic studies. We therefore characterized the impact of pan-HDAC inhibitor, panobinostat, and class I HDAC inhibitor, nanatinostat, on the growth, survival, and lytic reactivation of four EBV-positive cell lines: P3HR1-ZHT BL, Jijoye BL, IBL-1 immunoblastic lymphoma, and de novo infection derived lymphoblastoid cell lines (LCL). All lines were sensitive, enabling us to define ranges of sensitivity within which to use single cell approaches to assess early EBV lytic gene expression, cell cycle state, and apoptosis. We observed that each EBV-positive model of malignancy responded uniquely to the same HDAC inhibitors and that lytic reactivation was successful in only a small percentage of the cell population. To elucidate the potential role of host factors in preventing successful lytic reactivation, we performed single-cell RNA sequencing on the P3HR1-ZHT BL line treated with the HDAC inhibitor panobinostat. We observed that abortive lytic cells, or cells that do not successfully progress through the lytic cycle, upregulated genes downstream of NF-{kappa}B activity. Additionally, genes involved in immune signaling including the CD137/CD137L signaling axis, were upregulated in abortive lytic cells. These data have important implications for how we approach oncolytic therapies for EBV-associated malignancies. AUTHOR SUMMARYEpstein-Barr virus (EBV) is an extremely prevalent human herpesvirus that is associated with a variety of cancers and autoimmune diseases. EBV establishes latent infection in the host and, under various circumstances, can reactivate the lytic cycle to produce more infectious particles. In the context of EBV-associated malignancies, the virus is most often maintained in a latent state, which makes it difficult to target with pharmaceuticals. To develop more viral targeted strategies, kick and kill regiments have been investigated. This therapy involves reactivating the virus with an HDAC inhibitor followed by treatment with an antiviral drug. It is well established that reactivating EBV with pharmaceuticals is often inefficient and leads to heterogeneous responses, including an abortive lytic trajectory. To better characterize the overall effect of two classes of HDAC inhibitors in various models of EBV-associated malignancies, we utilized single-cell techniques to capture various responses to stimuli. Consistent with prior studies, HDAC inhibition led to both successful and abortive lytic populations. Single-cell RNA sequencing provided evidence of upregulated immune signaling pathways in this abortive lytic population. This study provides in depth characterization of lytic reactivation with a biologically relevant stimulus.

microbiology↗

bioRxiv2024

Fatty acid desaturases link cell metabolism pathways to promote proliferation of Epstein-Barr virus-infected B cells

Epstein-Barr virus (EBV) is a gamma herpesvirus that infects up to 95% of the human population by adulthood, typically remaining latent in the host memory B cell pool. In immunocompromised individuals, EBV can drive the transformation and rapid proliferation of infected B cells, ultimately resulting in neoplasia. The same transformation process can be induced in vitro, with EBV-infected peripheral blood mononuclear cells (PBMCs) forming immortalized lymphoblastoid cell lines (LCLs) within weeks. In this study, we found that the fatty acid desaturases stearoyl-CoA desaturase 1 (SCD1) and fatty acid desaturase 2 (FADS2) are upregulated by EBV, and crucial for EBV-induced B cell proliferation. Additionally, we found that pharmacological and genetic inhibition of both SCD1 and FADS2 results in a significantly greater reduction in proliferation and cell cycle arrest, compared to perturbing either enzyme individually. Additionally, we found that inhibiting either SCD1 or FADS2 alone hypersensitizes LCLs to palmitate-induced apoptosis, recapitulating studies in other tissue types. Further lipidomic and metabolic analysis of dual SCD1/FADS2-inhibited LCLs revealed an increase in free unsaturated fatty acids, a reduction of oxidative phosphorylation, and a reduction of glycolysis, thereby linking the activity of SCD1 and FADS2 to overall growth-promoting metabolism. Lastly, we show that SCD1 and FADS2 are important in the growth of clinically derived EBV+ immunoblastic lymphoma cells. Collectively, these data demonstrate a previously uncharacterized role of lipid desaturation in EBV+ transformed B cell proliferation, revealing a metabolic pathway that can be targeted in future anti-lymphoma therapies.

microbiology↗

bioRxiv2022

Fate-resolved gene regulatory signatures of individual B lymphocytes in the early stages of Epstein-Barr Virus infection

Epstein-Barr Virus (EBV) infection of B lymphocytes elicits diverse host responses via complex, well-adapted transcriptional control dynamics. Consequently, this host-pathogen interaction provides a powerful system to explore fundamental cellular processes that contribute to consensus fate decisions including cell cycle arrest, apoptosis, proliferation, and differentiation. Here we capture these responses and fates with matched single-cell transcriptomics and chromatin accessibility, from which we construct a genome-wide multistate model of early infection dynamics. Notably, our model captures a previously uncharacterized EBV+ analog of a multipotent activated precursor state that can yield early memory B cells. We also find that a marked global reduction in host chromatin accessibility occurs during the first stages of infection in subpopulations of EBV+ cells that display senescent and pre-apoptotic hallmarks induced by innate antiviral sensing and proliferation-linked DNA damage. However, cells in proliferative infection trajectories exhibit greater accessibility at select host sites linked to B cell activation and survival genes as well as key regions within the viral genome. To further investigate such loci, we implement a bioinformatic workflow (crisp-ATAC) to identify phenotype-resolved regulatory signatures. This customizable method applies user-specified logical criteria to produce genome-wide single-cell ATAC-and ChIP-seq range intersections that are used as inputs for cis-linkage prediction and ontology tools. The resulting tri-modal data yield exquisitely detailed hierarchical perspectives of the transforming regulatory landscape during critical stages of an oncogenic viral infection that simulates antigen-induced B cell activation and differentiation. We anticipate these resources will guide investigations of gene regulatory modules controlling EBV-host dynamics, B cell effector fates, and lymphomagenesis. To demonstrate the utility of this resource, this work concludes with the discovery of EBV infection dynamics in FCRL4+ / TBX21+ Tissue-Like Memory B cells, an unconventional subset with notable associations to numerous immune disorders.

immunology↗