Zidovudine-based lytic-inducing chemotherapy for Epstein-Barr virus-related lymphomas

Disentangling multiple sclerosis phenotypes through Mendelian disorders: A network approach

BACKGROUND

The increasing knowledge about multiple sclerosis (MS) pathophysiology has reinforced the need for an improved description of disease phenotypes, connected to disease biology. Growing evidence indicates that complex diseases constitute phenotypical and genetic continuums with "simple," monogenic disorders, suggesting shared pathomechanisms.

OBJECTIVES

The objective of this study was to depict a novel MS phenotypical framework leveraging shared physiopathology with Mendelian diseases and to identify phenotype-specific candidate drugs.

METHODS

We performed an enrichment testing of MS-associated variants with Mendelian disorders genes. We defined a "MS-Mendelian network," further analyzed to define enriched phenotypic subnetworks and biological processes. Finally, a network-based drug screening was implemented.

RESULTS

Starting from 617 MS-associated loci, we showed a significant enrichment of monogenic diseases (p < 0.001). We defined an MS-Mendelian molecular network based on 331 genes and 486 related disorders, enriched in four phenotypic classes: neurologic, immunologic, metabolic, and visual. We prioritized a total of 503 drugs, of which 27 molecules active in 3/4 phenotypical subnetworks and 140 in subnetwork pairs.

CONCLUSION

The genetic architecture of MS contains the seeds of pathobiological multiplicities shared with immune, neurologic, metabolic and visual monogenic disorders. This result may inform future classifications of MS endophenotypes and support the development of new therapies in both MS and rare diseases.

EBV+ lymphoproliferative diseases: opportunities for leveraging EBV as a therapeutic target

Epstein-Barr virus (EBV) is a ubiquitous human tumor virus, which contributes to the development of lymphoproliferative disease, most notably in patients with impaired immunity. EBV-associated lymphoproliferation is characterized by expression of latent EBV proteins and ranges in severity from a relatively benign proliferative response to aggressive malignant lymphomas. The presence of EBV can also serve as a unique target for directed therapies for the treatment of EBV lymphoproliferative diseases, including T cell-based immune therapies. In this review, we describe the EBV-associated lymphoproliferative diseases and particularly focus on the therapies that target EBV.

The Anti-Angiogenic Effects of Anti-Human Immunodeficiency Virus Drugs

The growth and metastasis of malignant tumors benefit from the formation of blood vessels within the tumor area. There, new vessels originate from angiogenesis (the sprouting of pre-existing neighboring vessels) and/or vasculogenesis (the mobilization of bone marrow-derived endothelial cell precursors which incorporate in tumor vasculature and then differentiate into mature endothelial cells). These events are induced by soluble molecules (the angiogenic factors) and modulated by endothelial cell interactions with the perivascular matrix. Given angiogenesis/vasculogenesis relevance to tumor progression, anti-angiogenic drugs are often employed to buttress surgery, chemotherapy or radiation therapy in the treatment of a wide variety of cancers. Most of the anti-angiogenic drugs have been developed to functionally impair the angiogenic vascular endothelial growth factor: however, this leaves other angiogenic factors unaffected, hence leading to drug resistance and escape. Other anti-angiogenic strategies have exploited classical inhibitors of enzymes remodeling the perivascular matrix. Disappointingly, these inhibitors have been found toxic and/or ineffective in clinical trials, even though they block angiogenesis in pre-clinical models. These findings are stimulating the identification of other anti-angiogenic compounds. In this regard, it is noteworthy that drugs utilized for a long time to counteract human immune deficiency virus (HIV) can directly and effectively hamper molecular pathways leading to blood vessel formation. In this review the mechanisms leading to angiogenesis and vasculogenesis, and their susceptibility to anti-HIV drugs will be discussed.

Schizophrenia is Associated With an Aberrant Immune Response to Epstein-Barr Virus

BACKGROUND

Epstein-Barr virus (EBV) is a highly prevalent human herpesvirus capable of infecting the central nervous system and establishing persistent infection.

METHODS

We employed solid phase immunoassay techniques to measure immunoglobulin G (IgG) class antibodies to EBV virions and defined proteins in 432 individuals with schizophrenia and 311 individuals without a history of a psychiatric disorder. Western blot testing was performed to document reactivity to specific EBV proteins. Polygenic risk for schizophrenia was calculated from genome sequencing arrays. Levels of antibodies between the groups were compared by multivariate analyses incorporating clinical, genetic, and demographic measures.

RESULTS

Individuals with schizophrenia had marked elevations in the levels of antibodies to EBV virions as compared to the control population. Further analyses indicated increased levels of reactivity to EBV-viral capsid antibody (VCA) but not to EBV nuclear antigen-1 (EBNA-1) or to other human herpesviruses. Western blot analysis confirmed increased reactivity to VCA proteins in the group of individuals with schizophrenia and documented a lack of increased levels of antibodies to EBNA-1. Genetic analyses indicated an additive effect of increased levels of antibodies to EBV virions and genetic susceptibility to schizophrenia, with individuals with elevated levels of both type of markers having a greater than 8.5-fold odds of a schizophrenia diagnosis.

CONCLUSIONS

Individuals with schizophrenia have increased levels of antibodies to some but not all EBV proteins indicating an aberrant response to EBV infection. This aberrant response may contribute to the immunopathology of schizophrenia and related disorders.

Primary Intramedullary Spinal Cord Lymphoma Presenting as a Cervical Ring-Enhancing Lesion in an AIDS Patient

Primary intramedullary spinal cord lymphoma (PISCL) is rare and constitutes only 1% of central nervous system lymphomas. We report a case of PISCL in a 37-year-old man with advanced AIDS. To our knowledge, only 4 cases of PISCL in the setting of HIV/AIDS have been reported in the literature. Despite treatment, prognosis remains dismal.

Extra-telomeric functions of telomerase in the pathogenesis of Epstein-Barr virus-driven B-cell malignancies and potential therapeutic implications

The Epstein-Barr virus (EBV) is a ubiquitous human γ-herpesvirus causally linked to a broad spectrum of both lymphoid and epithelial malignancies. In order to maintain its persistence in host cells and promote tumorigenesis, EBV must restrict its lytic cycle, which would ultimately lead to cell death, selectively express latent viral proteins, and establish an unlimited proliferative potential. The latter step depends on the maintenance of telomere length provided by telomerase. The viral oncoprotein LMP-1 activates TERT, the catalytic component of telomerase. In addition to its canonical role in stabilizing telomeres, TERT may promote EBV-driven tumorigenesis through extra-telomeric functions. TERT contributes toward preserving EBV latency; in fact, through the NOTCH2/BATF pathway, TERT negatively affects the expression of BZLF1, the master regulator of the EBV lytic cycle. In contrast, TERT inhibition triggers a complete EBV lytic cycle, leading to the death of EBV-infected cells. Interestingly, short-term TERT inhibition causes cell cycle arrest and apoptosis, partly by inducing telomere-independent activation of the ATM/ATR/TP53 pathway. Importantly, TERT inhibition also sensitizes EBV-positive tumor cells to antiviral therapy and enhances the pro-apoptotic effects of chemotherapeutic agents. We provide here an overview on how the extra-telomeric functions of TERT contribute to EBV-driven tumorigenesis. We also discuss the potential therapeutic approach of TERT inhibition in EBV-driven malignancies.

Complete and Durable Responses in Primary Central Nervous System Posttransplant Lymphoproliferative Disorder with Zidovudine, Ganciclovir, Rituximab, and Dexamethasone

Purpose: Primary central nervous system posttransplant lymphoproliferative disorder (PCNS-PTLD) is a complication of solid organ transplantation with a poor prognosis and typically associated with Epstein-Barr virus (EBV). We hypothesized EBV lytic-phase protein expression would allow successful treatment with antiviral therapy.Patients and Methods: Thirteen patients were treated with zidovudine (AZT), ganciclovir (GCV), dexamethasone, and rituximab in EBV⁺ PCNS-PTLD. Twice-daily, intravenous AZT 1,500 mg, GCV 5 mg/kg, and dexamethasone 10 mg were given for 14 days. Weekly rituximab 375 mg/m² was delivered for the first 4 weeks. Twice-daily valganciclovir 450 mg and AZT 300 mg started day 15. Lytic and latent protein expression was assessed using in situ hybridization and immunohistochemistry. Immunoblot assay assessed lytic gene activation. Cells transfected with lytic kinase vectors were assessed for sensitivity to our therapy using MTS tetrazolium and flow cytometry.Results: The median time to response was 2 months. Median therapy duration was 26.5 months. Median follow-up was 52 months. The estimated 2-year overall survival (OS) was 76.9% (95% CI, 44.2%-91.9%). Overall response rate (ORR) was 92% (95% CI, 64%-100%). BXLF1/vTK and BGLF4 expression was found in the seven tumor biopsies evaluated. Lytic gene expression was induced in vitro using the four-drug regimen. Transfection with viral kinase cDNA increased cellular sensitivity to antiviral therapy.Conclusions: EBV⁺ PCNS-PTLD expressed lytic kinases and therapy with AZT, GCV, rituximab and dexamethasone provided durable responses. Induction of the lytic protein expression and increased cellular sensitivity to antiviral therapy after transfection with viral kinase cDNA provides a mechanistic rationale for our approach. Clin Cancer Res; 24(14); 3273-81. ©2018 AACR.

Primary CNS lymphoma in HIV infection

Primary CNS lymphoma (PCNSL) has been designated an acquired immune deficiency syndrome (AIDS)-defining disease since 1983 and accounts for up to 15% of non-Hodgkin lymphomas in human immunodeficiency virus (HIV) patients. The majority of HIV patients are Epstein-Barr virus (EBV)-related. The most likely etiology is ineffective immunoregulation of EBV, inducing oncogenic protein expression, and subsequent loss of apoptosis and increased proliferation of lymphocytes. PCNSL generally presents with supratentorial, single or multiple, contrast-enhancing lesions. Neurologic symptoms can be headache, cognitive function disorders, focal neurologic, deficit and epilepsy. Differential diagnosis includes other oncologic or infectious causes, with cerebral toxoplasmosis being the most important. Magnetic resonance imaging characteristics, activity on ²⁰¹thallium single-photon emission computed tomography, presence of EBV DNA in the cerebrospinal fluid, and toxoplasmosis serology can make either PCNSL or cerebral toxoplasmosis more or less likely. However, definitive diagnosis of PCNSL relies on histopathologic confirmation. First-choice treatment is combination antiretroviral therapy in combination with high-dose methotrexate(-based) chemotherapy in patients in whom this is feasible. Combination antiretroviral therapy combined with whole-brain radiotherapy may be an alternative. Treatment of EBV with antiviral agents such as ganciclovir or zidovudine may be beneficial, but this needs further study. Prognosis of HIV-related PCNSL is poor, with median survival varying from 2 to 4 months, but patients treated with chemotherapy do better (median survival 1.5 years).

The Epstein-Barr Virus (EBV) in T Cell and NK Cell Lymphomas: Time for a Reassessment

While Epstein-Barr virus (EBV) was initially discovered and characterized as an oncogenic virus in B cell neoplasms, it also plays a complex and multifaceted role in T/NK cell lymphomas. In B cell lymphomas, EBV-encoded proteins have been shown to directly promote immortalization and proliferation through stimulation of the NF-κB pathway and increased expression of anti-apoptotic genes. In the context of mature T/NK lymphomas (MTNKL), with the possible exception on extranodal NK/T cell lymphoma (ENKTL), the virus likely plays a more diverse and nuanced role. EBV has been shown to shape the tumor microenvironment by promoting Th2-skewed T cell responses and by increasing the expression of the immune checkpoint ligand PD-L1. The type of cell infected, the amount of plasma EBV DNA, and the degree of viral lytic replication have all been proposed to have prognostic value in T/NK cell lymphomas. Latency patterns of EBV infection have been defined using EBV-infected B cell models and have not been definitively established in T/NK cell lymphomas. Identifying the expression profile of EBV lytic proteins could allow for individualized therapy with the use of antiviral medications. More work needs to be done to determine whether EBV-associated MTNKL have distinct biological and clinical features, which can be leveraged for risk stratification, disease monitoring, and therapeutic purposes.

Primary Effusion Lymphoma (PEL)-Like Lymphoma in a Child With Congenital Immunodeficiency

Primary effusion lymphoma (PEL) is a rare lymphoma that occurs more frequently in immunocompromised adults and has a poor survival. We report a 9-year-old female with combined immunodeficiency with an Epstein-Barr virus positive/human herpes virus 8 negative PEL-like lymphoma. The treatment with systemic chemotherapy for non-Hodgkin lymphoma, zidovudine, and interferon-α failed to control disease progression. This is the first reported pediatric case of PEL-like lymphoma. Increased diagnostic awareness and more effective treatment strategies are needed for this rare lymphoma.

Structure and conformational analysis of the anti-HIV reverse transcriptase inhibitor AZT using MP2 and DFT methods. Differences with the natural nucleoside thymidine. Simulation of the 1st phosphorylation step with ATP

A comprehensive quantum-chemical investigation of the conformational landscape of the HIV-1 reverse transcriptase inhibitor AZT (3'-azido-3'-deoxythymidine) nucleoside analogue was carried out. The whole conformational parameters (χ, γ, β, δ, ϕ, P, νmax) were analysed as well as the NBO charges. The search located at least 55 stable structures, 9 of which were by MP2 within a 1 kcal mol(-1) electronic energy range of the global minimum. Most conformers were anti or high-anti around the glycoside bond and with North sugar ring puckering angles. The distribution of all the conformers according to the ranges of stability of the characteristic torsional angles was established. The results obtained were in accordance with those found in related anti-HIV nucleoside analogues. The best conformer in the anti form corresponded to the calculated values by MP2 of χ = -126.9°, β = 176.4° and γ = 49.1°. An analysis of the lowest vibrations in conformer C1 was carried out. The first hydration shell was simulated and the structural differences with the natural nucleoside deoxythymidine (dT) were determined. The first phosphorylation step was simulated by interacting ATP with the best hydrated clusters of AZT and dT. The Na cations act as a bridge between the phosphate moieties of ATP making it easy for -P3O3 to receive the H5' proton from AZT or dT. A proton-transfer mechanism is proposed through the water molecules. When the number of the water molecules surrounding AZT is lower than 8, the first phosphorylation step of AZT can be carried out. However, the appropriate orientation of the O5'-H in dT avoids this limitation and it can be performed with large numbers of water molecules.

Characterization of the enhanced apoptotic response to azidothymidine by pharmacological inhibition of NF-kB

AIMS

The present study addresses the issue of enhanced apoptotic response to AZT following co-treatment with an NF-kB inhibitor.

MAIN METHODS

To investigate this issue, different cell lines were assayed for susceptibility to AZT-mediated apoptosis without or with the addition of the NF-kB inhibitor Bay-11-7085. For further investigation, U937 cells were selected as good-responder cells to the combination treatment with 32 or 128 μM AZT, and 1 μM Bay-11-7085. Inhibition of NF-kB activation by Bay-11-7085 in cells treated with AZT was assayed through Western blot analysis of p65 expression and by EMSA. Involvement of the mitochondrial pathway of apoptosis in mechanisms underlying the improved effect of AZT following Bay-11-7085 co-treatment, was evaluated by assaying the cytochrome c release and the mitochondrial membrane potential (MMP) status using the JC-1 dye. Moreover, the transcriptional activity of both anti- and pro-apoptotic genes in U937 cells after combination treatment was quantitatively evaluated through real-time PCR.

KEY FINDINGS

We found that the combined treatment induced high levels of cytochrome c release and of MMP collapse in association with evident changes in the expression of both anti- and pro-apoptotic genes of the Bcl-2 family. Overexpression of Bcl-2 significantly suppressed the sensitization of U937 cells to an enhanced apoptotic response to AZT following co-treatment with the NF-kB inhibitor.

SIGNIFICANCE

The new findings suggest that a combination regimen based on AZT plus an NF-kB inhibitor could represent a new chemotherapeutic tool for retrovirus-related pathologies.

Epstein-Barr virus-associated smooth muscle tumors in children following solid organ transplantation: a review

EBV-SMT are a rare entity following organ transplantation. Given the rarity of the tumor, there is no standard approach to diagnosis and treatment. A literature search identified 28 reported cases of EBV-SMT in addition to our own experience with one case. The aim of this review is to summarize the existing data regarding pathogenesis, diagnosis, and treatment.

Epstein-Barr virus and telomerase: from cell immortalization to therapy

Overcoming cellular senescence is strictly required for virus-driven tumors, including those associated with Epstein-Barr virus (EBV). This critical step is successfully accomplished by EBV through TERT expression and telomerase activation in infected cells. We herein review the complex interplay between EBV and TERT/telomerase in EBV-driven tumorigenesis. Evidence accumulated so far clearly indicates that elucidation of this issue may offer promising opportunities for the design of innovative treatment modalities for EBV-associated malignancies. Indeed, several therapeutic strategies for telomerase inhibition have been developed and are being investigated in clinical trials. In this respect, our recent finding that TERT inhibition sensitizes EBV+ lymphoma cells to antivirals through activation of EBV lytic replication is particularly promising and provides a rationale for the activation of clinical studies aimed at assessing the effects of combination therapies with TERT inhibitors and antivirals for the treatment of EBV-associated malignancies.