Epstein-Barr virus infectious particles initiate B cell transformation and modulate cytokine response

ABSTRACT The Epstein-Barr virus (EBV) efficiently transforms primary B cells. Here, we show that this process starts immediately after cellular exposure to infectious viral particles. Virus binding to B cells led to the activation of intracytoplasmic tyrosine kinases and STAT3. Tegument proteins within the virion in turn activated the p38-MK2 pathway upon cell entry, independently of the viral DNA. Engagement of STAT3 and p38/MK2, two pro-inflammatory pathways, was essential for expression of the key EBV transforming gene EBNA2 but also facilitated IL-6 and TNFα release. However, these pathways simultaneously activated ZFP36L1, a stress response protein that targets transcripts with an AU-rich 3′UTR, to reduce IL-6 and TNFα transcription in infected cells. Expression of viral latent proteins after infection amplified the viral effects on p38 and MK2, but also on ZFP36L1, altogether resulting in a transitory and limited increase in IL-6 and TNFα transcription and release. Thus, EBV virions are not merely vehicles that allow injection of the viral DNA into the nucleus but manipulate cellular pathways to initiate transformation while limiting cytokine release. IMPORTANCE The Epstein-Barr virus efficiently infects and transforms B lymphocytes. During this process, infectious viral particles transport the viral genome to the nucleus of target cells. We show here that these complex viral structures serve additional crucial roles by activating transcription of the transforming genes encoded by the virus. We show that components of the infectious particle sequentially activate proinflammatory B lymphocyte signaling pathways that, in turn, activate viral gene expression but also cause cytokine release. However, virus infection activates expression of ZFP36L1, an RNA-binding stress protein that limits the length and the intensity of the cytokine response. Thus, the infectious particles can activate viral gene expression and initiate cellular transformation at the price of a limited immune response

Metagenomic analysis of primary colorectal carcinomas and their metastases identifies potential microbial risk factors

The paucity of microbiome studies at intestinal tissues has contributed to a yet limited understanding of potential viral and bacterial cofactors of colorectal cancer (CRC) carcinogenesis or progression. We analysed whole‐genome sequences of CRC primary tumours, their corresponding metastases and matched normal tissue for sequences of viral, phage and bacterial species. Bacteriome analysis showed Fusobacterium nucleatum, Streptococcus sanguinis, F. Hwasookii, Anaerococcus mediterraneensis and further species enriched in primary CRCs. The primary CRC of one patient was enriched for F. alocis, S. anginosus, Parvimonas micra and Gemella sp. 948. Enrichment of Escherichia coli strains IAI1, SE11, K‐12 and M8 was observed in metastases together with coliphages enterobacteria phage φ80 and Escherichia phage VT2φ_272. Virome analysis showed that phages were the most preponderant viral species (46%), the main families being Myoviridae, Siphoviridae and Podoviridae. Primary CRCs were enriched for bacteriophages, showing five phages (Enterobacteria, Bacillus, Proteus, Streptococcus phages) together with their pathogenic hosts in contrast to normal tissues. The most frequently detected, and Blast‐confirmed, viruses included human endogenous retrovirus K113, human herpesviruses 7 and 6B, Megavirus chilensis, cytomegalovirus (CMV) and Epstein–Barr virus (EBV), with one patient showing EBV enrichment in primary tumour and metastases. EBV was PCR‐validated in 80 pairs of CRC primary tumour and their corresponding normal tissues; in 21 of these pairs (26.3%), it was detectable in primary tumours only. The number of viral species was increased and bacterial species decreased in CRCs compared with normal tissues, and we could discriminate primary CRCs from metastases and normal tissues by applying the Hutcheson t‐test on the Shannon indices based on viral and bacterial species. Taken together, our results descriptively support hypotheses on microorganisms as potential (co)risk factors of CRC and extend putative suggestions on critical microbiome species in CRC metastasis

Spontaneous lymphoblastoid cell lines from patients with Epstein-Barr virus infection show highly variable proliferation characteristics that correlate with the expression levels of viral microRNAs.

The Epstein-Barr virus (EBV) induces B-cell proliferation with high efficiency through expression of latent proteins and microRNAs. This process takes place in vivo soon after infection, presumably to expand the virus reservoir, but can also induce pathologies, e.g. an infectious mononucleosis (IM) syndrome after primary infection or a B-cell lymphoproliferation in immunosuppressed individuals. In this paper, we investigated the growth characteristics of EBV-infected B-cells isolated from transplant recipients or patients with IM. We found that these cells grew and withstood apoptosis at highly variable rates, suggesting that the expansion rate of the infected B-cells widely varies between individuals, thereby influencing the size of the B-cell reservoir and the ability to form tumors in infected individuals. All viruses investigated were type 1 and genetically close to western strains. EBV-infected B-cells expressed the transforming EBV latent genes and microRNAs (miRNAs) at variable levels. We found that the B-cell growth rates positively correlated with the BHRF1 miRNA levels. Comparative studies showed that infected B-cells derived from transplant recipients with iEBVL on average expressed higher levels of EBV miR-BHRF1 miRNAs and grew more rapidly than B-cells from IM patients, suggesting infection by more transforming viruses. Altogether, these findings suggest that EBV infection has a highly variable impact on the B-cell compartment that probably reflects the genetic diversity of both the virus and the host. It also demonstrates the unexpected finding that B-cells from different individuals can grow at different speed under the influence of the same virus infection

Efficacy and Safety of Checkpoint Inhibitor Treatment in Patients with Advanced Renal or Urothelial Cell Carcinoma and Concomitant Chronic Kidney Disease: A Retrospective Cohort Study

Background: Checkpoint inhibitors are a standard of care in the treatment of advanced renal cell carcinoma (RCC) and urothelial carcinoma (UC). Patients with these tumors often suffer from concomitant chronic kidney disease (CKD). Limited data are available on the efficacy and toxicity of checkpoint inhibitors in patients with CKD. Methods: We retrospectively analyzed 126 patients who received checkpoint inhibitors for RCC (n = 85) or UC (n = 41) and analyzed the frequency of treatment- and immune-related adverse events (AEs). We performed a multivariate analysis to determine progression-free survival (PFS) and overall survival (OS). Results: A total of 38.9% of patients had CKD. Frequencies of general AEs (49.0% in CKD vs. 48.1%, p > 0.99999) and immune-related AEs (28.6 vs. 24.7%, p ≥ 0.9999) did not significantly differ between the groups. There was no difference in PFS for patients with RCC or UC and CKD or without CKD (RCC: 6.81 vs. 7.54 months, HR 1.000 (95%CI 0.548–01.822), p = 0.999; UC:2.33 vs. 3.67 months, HR 01.492 (95%CI 0.686–3.247), p = 0.431). CKD appeared to be a potential effect modifier for OS in both RCC and UC (RCC: NR vs. 23.9 months, HR 0.502 (95%CI 0.219–1.152), p = 0.104; UC:18.84 vs. 15.42 months, HR 0.656 (95%CI 0.296–1.454), p = 0.299). Conclusions: Checkpoint inhibitor treatment in our cohort of patients with CKD was as safe and efficient as in the cohort of patients without CKD

BTG1 inactivation drives lymphomagenesis and promotes lymphoma dissemination through activation of BCAR1

International audienceAbstract Understanding the functional role of mutated genes in cancer is required to translate the findings of cancer genomics into therapeutic improvement. BTG1 is recurrently mutated in the MCD/C5 subtype of diffuse large B-cell lymphoma (DLBCL), which is associated with extranodal dissemination. Here, we provide evidence that Btg1 knock out accelerates the development of a lethal lymphoproliferative disease driven by Bcl2 overexpression. Furthermore, we show that the scaffolding protein BCAR1 is a BTG1 partner. Moreover, after BTG1 deletion or expression of BTG1 mutations observed in patients with DLBCL, the overactivation of the BCAR1-RAC1 pathway confers increased migration ability in vitro and in vivo. These modifications are targetable with the SRC inhibitor dasatinib, which opens novel therapeutic opportunities in BTG1 mutated DLBCL

EBV-tissue positive primary CNS lymphoma occurring after immunosuppression is a distinct immunobiological entity

Primary central nervous system lymphoma (PCNSL) is confined to the brain, eyes, and cerebrospinal fluid without evidence of systemic spread. Rarely, PCNSL occurs in the context of immunosuppression, e.g. post-transplant lymphoproliferative disorders (PTLD) or HIV (AIDS-related PCNSL). These cases are poorly characterized, have dismal outcome and are typically Epstein-Barr virus (EBV)-tissue positive. We used targeted sequencing and digital multiplex gene expression to compare the genetic landscape and tumor microenvironment (TME) of 91 PCNSL tissues all with diffuse large B-cell lymphoma histology. 47 were EBV-tissue negative: 45 EBV(-) HIV(-) PCNSL, 2 EBV(-) HIV(+) PCNSL; and 44 were EBV-tissue positive: 23 EBV(+) HIV(+) PCNSL, 21 EBV(+) HIV(-) PCNSL. As with prior studies, EBV(-) HIV(-) PCNSL had frequent MYD88, CD79B and PIM1 mutations, and enrichment for the activated B-cell (ABC) cell-of-origin (COO) sub-type. In contrast, these mutations were absent in all EBV-tissue positive cases and ABC frequency was low. Furthermore, copy number loss in HLA-class I/II and antigen presenting/processing genes were rarely observed, indicating retained antigen presentation. To counter this, EBV(+) HIV(-) PCNSL had a tolerogenic TME with elevated macrophage and immune-checkpoint gene expression, whereas AIDS-related PCNSL had low CD4 gene counts. EBV-tissue positive PCNSL in the immunosuppressed is immunobiologically distinct from EBV(-) HIV(-) PCNSL, and despite expressing an immunogenic virus retains the ability to present EBV-antigens. Results provide a framework for targeted treatment