The detection of CMV pp65 and IE1 in glioblastoma multiforme. J Neurooncol. 2011;103:231-238. [PMID: 20820869 DOI: 10.1007/s11060-010-0383-6]

Glioblastoma Vaccines as Promising Immune-Therapeutics: Challenges and Current Status

Glioblastoma (GBM) is the most common and aggressive malignant brain tumor. Standard treatments including surgical resection, radiotherapy, and chemotherapy, have failed to significantly improve the prognosis of glioblastoma patients. Currently, immunotherapeutic approaches based on vaccines, chimeric antigen-receptor T-cells, checkpoint inhibitors, and oncolytic virotherapy are showing promising results in clinical trials. The combination of different immunotherapeutic approaches is proving satisfactory and promising. In view of the challenges of immunotherapy and the resistance of glioblastomas, the treatment of these tumors requires further efforts. In this review, we explore the obstacles that potentially influence the efficacy of the response to immunotherapy and that should be taken into account in clinical trials. This article provides a comprehensive review of vaccine therapy for glioblastoma. In addition, we identify the main biomarkers, including isocitrate dehydrogenase, epidermal growth factor receptor, and telomerase reverse transcriptase, known as potential immunotherapeutic targets in glioblastoma, as well as the current status of clinical trials. This paper also lists proposed solutions to overcome the obstacles facing immunotherapy in glioblastomas.

RNA aggregates harness the danger response for potent cancer immunotherapy

Cancer immunotherapy remains limited by poor antigenicity and a regulatory tumor microenvironment (TME). Here, we create "onion-like" multi-lamellar RNA lipid particle aggregates (LPAs) to substantially enhance the payload packaging and immunogenicity of tumor mRNA antigens. Unlike current mRNA vaccine designs that rely on payload packaging into nanoparticle cores for Toll-like receptor engagement in immune cells, systemically administered RNA-LPAs activate RIG-I in stromal cells, eliciting massive cytokine/chemokine response and dendritic cell/lymphocyte trafficking that provokes cancer immunogenicity and mediates rejection of both early- and late-stage murine tumor models. In client-owned canines with terminal gliomas, RNA-LPAs improved survivorship and reprogrammed the TME, which became "hot" within days of a single infusion. In a first-in-human trial, RNA-LPAs elicited rapid cytokine/chemokine release, immune activation/trafficking, tissue-confirmed pseudoprogression, and glioma-specific immune responses in glioblastoma patients. These data support RNA-LPAs as a new technology that simultaneously reprograms the TME while eliciting rapid and enduring cancer immunotherapy.

Tumor Antigens beyond the Human Exome

With the advent of immunotherapeutics, a new era in the combat against cancer has begun. Particularly promising are neo-epitope-targeted therapies as the expression of neo-antigens is tumor-specific. In turn, this allows the selective targeting and killing of cancer cells whilst healthy cells remain largely unaffected. So far, many advances have been made in the development of treatment options which are tailored to the individual neo-epitope repertoire. The next big step is the achievement of efficacious "off-the-shelf" immunotherapies. For this, shared neo-epitopes propose an optimal target. Given the tremendous potential, a thorough understanding of the underlying mechanisms which lead to the formation of neo-antigens is of fundamental importance. Here, we review the various processes which result in the formation of neo-epitopes. Broadly, the origin of neo-epitopes can be categorized into three groups: canonical, noncanonical, and viral neo-epitopes. For the canonical neo-antigens that arise in direct consequence of somatic mutations, we summarize past and recent findings. Beyond that, our main focus is put on the discussion of noncanonical and viral neo-epitopes as we believe that targeting those provides an encouraging perspective to shape the future of cancer immunotherapeutics.

Immunosenescence and Cytomegalovirus: Exploring Their Connection in the Context of Aging, Health, and Disease

Aging induces numerous physiological alterations, with immunosenescence emerging as a pivotal factor. This phenomenon has attracted both researchers and clinicians, prompting profound questions about its implications for health and disease. Among the contributing factors, one intriguing actor in this complex interplay is human cytomegalovirus (CMV), a member of the herpesvirus family. Latent CMV infection exerts a profound influence on the aging immune system, potentially contributing to age-related diseases. This review delves into the intricate relationship between immunosenescence and CMV, revealing how chronic viral infection impacts the aging immune landscape. We explore the mechanisms through which CMV can impact both the composition and functionality of immune cell populations and induce shifts in inflammatory profiles with aging. Moreover, we examine the potential role of CMV in pathologies such as cardiovascular diseases, cancer, neurodegenerative disorders, COVID-19, and Long COVID. This review underlines the importance of understanding the complex interplay between immunosenescence and CMV. It offers insights into the pathophysiology of aging and age-associated diseases, as well as COVID-19 outcomes among the elderly. By unraveling the connections between immunosenescence and CMV, we gain a deeper understanding of aging's remarkable journey and the profound role that viral infections play in transforming the human immune system.

Higher Human Cytomegalovirus (HCMV) Specific IgG Antibody Levels in Plasma Samples from Patients with Metastatic Brain Tumors Are Associated with Longer Survival

Background: Human cytomegalovirus (HCMV) has been detected in tissue samples from patients with glioblastoma but little is known about the systemic immunological response to HCMV in these patients. Objectives: To investigate the presence and clinical significance of HCMV antibodies levels in plasma samples obtained from patients with brain tumors. Materials and Methods: HCMV-specific IgG and IgM antibody levels were determined in 59 plasma samples collected from brain tumor patients included in a prospective study and in 114 healthy individuals. We examined if the levels of HCMV specific antibodies varied in patients with different brain tumor diagnoses compared to healthy individuals, and if antibody levels were predictive for survival time. Results: HCMV specific IgG antibodies were detected by ELISA in 80% and 89% of patients with GBM and astrocytoma grades II-III, respectively, in all samples (100%) from patients with secondary GBM and brain metastases, as well as in 80% of healthy donors (n = 114). All plasma samples were negative for HCMV-IgM. Patients with brain metastases who had higher plasma HCMV-IgG titers had longer survival times (p = 0.03). Conclusions: HCMV specific IgG titers were higher among all brain tumor patient groups compared with healthy donors, except for patients with secondary GBM. Higher HCMV specific IgG levels in patients with brain metastases but not in patients with primary brain tumors were associated with prolonged survival time.

Immunotherapy for Recurrent Glioma-From Bench to Bedside

Glioma is the most aggressive malignant tumor of the central nervous system, and most patients suffer from a recurrence. Unfortunately, recurrent glioma often becomes resistant to established chemotherapy and radiotherapy treatments. Immunotherapy, a rapidly developing anti-tumor therapy, has shown a potential value in treating recurrent glioma. Multiple immune strategies have been explored. The most-used ones are immune checkpoint blockade (ICB) antibodies, which are barely effective in monotherapy. However, when combined with other immunotherapy, especially with anti-angiogenesis antibodies, ICB has shown encouraging efficacy and enhanced anti-tumor immune response. Oncolytic viruses and CAR-T therapies have shown promising results in recurrent glioma through multiple mechanisms. Vaccination strategies and immune-cell-based immunotherapies are promising in some subgroups of patients, and multiple new tumor antigenic targets have been discovered. In this review, we discuss current applicable immunotherapies and related mechanisms for recurrent glioma, focusing on multiple preclinical models and clinical trials in the last 5 years. Through reviewing the current combination of immune strategies, we would like to provide substantive thoughts for further novel therapeutic regimes treating recurrent glioma.

EphA2 is a functional entry receptor for HCMV infection of glioblastoma cells

Human cytomegalovirus (HCMV) infection is associated with human glioblastoma, the most common and aggressive primary brain tumor, but the underlying infection mechanism has not been fully demonstrated. Here, we show that EphA2 was upregulated in glioblastoma and correlated with the poor prognosis of the patients. EphA2 silencing inhibits, whereas overexpression promotes HCMV infection, establishing EphA2 as a crucial cell factor for HCMV infection of glioblastoma cells. Mechanistically, EphA2 binds to HCMV gH/gL complex to mediate membrane fusion. Importantly, the HCMV infection was inhibited by the treatment of inhibitor or antibody targeting EphA2 in glioblastoma cells. Furthermore, HCMV infection was also impaired in optimal glioblastoma organoids by EphA2 inhibitor. Taken together, we propose EphA2 as a crucial cell factor for HCMV infection in glioblastoma cells and a potential target for intervention.

mRNA aggregates harness danger response for potent cancer immunotherapy

Messenger RNA (mRNA) has emerged as a remarkable tool for COVID-19 prevention but its use for induction of therapeutic cancer immunotherapy remains limited by poor antigenicity and a regulatory tumor microenvironment (TME). Herein, we develop a facile approach for substantially enhancing immunogenicity of tumor-derived mRNA in lipid-particle (LP) delivery systems. By using mRNA as a molecular bridge with ultrapure liposomes and foregoing helper lipids, we promote the formation of 'onion-like' multi-lamellar RNA-LP aggregates (LPA). Intravenous administration of RNA-LPAs mimics infectious emboli and elicits massive DC/T cell mobilization into lymphoid tissues provoking cancer immunogenicity and mediating rejection of both early and late-stage murine tumor models. Unlike current mRNA vaccine designs that rely on payload packaging into nanoparticle cores for toll-like receptor engagement, RNA-LPAs stimulate intracellular pathogen recognition receptors (RIG-I) and reprogram the TME thus enabling therapeutic T cell activity. RNA-LPAs were safe in acute/chronic murine GLP toxicology studies and immunologically active in client-owned canines with terminal gliomas. In an early phase first-in-human trial for patients with glioblastoma, we show that RNA-LPAs encoding for tumor-associated antigens elicit rapid induction of pro-inflammatory cytokines, mobilization/activation of monocytes and lymphocytes, and expansion of antigen-specific T cell immunity. These data support the use of RNA-LPAs as novel tools to elicit and sustain immune responses against poorly immunogenic tumors.

Myeloid cell-targeted therapies for solid tumours

Myeloid cells are the most abundant immune components of the tumour microenvironment, where they have a variety of functions, ranging from immunosuppressive to immunostimulatory roles. The myeloid cell compartment comprises many different cell types, including monocytes, macrophages, dendritic cells and granulocytes, that are highly plastic and can differentiate into diverse phenotypes depending on cues received from their microenvironment. In the past few decades, we have gained a better appreciation of the complexity of myeloid cell subsets and how they are involved in tumour progression and resistance to cancer therapies, including immunotherapy. In this Review, we highlight key features of monocyte and macrophage biology that are being explored as potential targets for cancer therapies and what aspects of myeloid cells need a deeper understanding to identify rational combinatorial strategies to improve clinical outcomes of patients with cancer. We discuss therapies that aim to modulate the functional activities of myeloid cell populations, impacting their recruitment, survival and activity in the tumour microenvironment, acting at the level of cell surface receptors, signalling pathways, epigenetic machinery and metabolic regulators. We also describe advances in the development of genetically engineered myeloid cells for cancer therapy.

Next Steps for Immunotherapy in Glioblastoma

Outcomes for glioblastoma (GBM) patients undergoing standard of care treatment remain poor. Here we discuss the portfolio of previously investigated immunotherapies for glioblastoma, including vaccine therapy and checkpoint inhibitors, as well as novel emerging therapeutic approaches. In addition, we explore the factors that potentially influence response to immunotherapy, which should be considered in future research aimed at improving immunotherapy efficacy.

Cytomegalovirus-Specific Immunotherapy for Glioblastoma Treatments

Over the last two decades, numerous studies have investigated the presence of human cytomegalovirus (CMV) within glioblastoma or gliomas; however, the results are severely conflicting. While a few researchers have suggested the potential benefits of cytotoxic T lymphocyte or dendritic cell-based vaccines for recurrent or newly diagnosed glioblastoma patients, several studies did not at all agree with the existence of CMV in glioblastoma cells. In this review, we summarized the conflicting results and issues about the detection of CMV in glioblastoma or glioma patients. We also provided the clinical data of published and unpublished clinical trials using CMV-specific immunotherapy for glioblastomas.

Translational landscape of glioblastoma immunotherapy for physicians: guiding clinical practice with basic scientific evidence

Despite recent advances in cancer therapeutics, glioblastoma (GBM) remains one of the most difficult cancers to treat in both the primary and recurrent settings. GBM presents a unique therapeutic challenge given the immune-privileged environment of the brain and the aggressive nature of the disease. Furthermore, it can change phenotypes throughout the course of disease—switching between mesenchymal, neural, and classic gene signatures, each with specific markers and mechanisms of resistance. Recent advancements in the field of immunotherapy—which utilizes strategies to reenergize or alter the immune system to target cancer—have shown striking results in patients with many types of malignancy. Immune checkpoint inhibitors, adoptive cellular therapy, cellular and peptide vaccines, and other technologies provide clinicians with a vast array of tools to design highly individualized treatment and potential for combination strategies. There are currently over 80 active clinical trials evaluating immunotherapies for GBM, often in combination with standard secondary treatment options including re-resection and anti-angiogenic agents, such as bevacizumab. This review will provide a clinically focused overview of the immune environment present in GBM, which is frequently immunosuppressive and characterized by M2 macrophages, T cell exhaustion, enhanced transforming growth factor-β signaling, and others. We will also outline existing immunotherapeutic strategies, with a special focus on immune checkpoint inhibitors, chimeric antigen receptor therapy, and dendritic cell vaccines. Finally, we will summarize key discoveries in the field and discuss currently active clinical trials, including combination strategies, burgeoning technology like nucleic acid and nanoparticle therapy, and novel anticancer vaccines. This review aims to provide the most updated summary of the field of immunotherapy for GBM and offer both historical perspective and future directions to help inform clinical practice.

Novel Pharmacological Treatment Options in Pediatric Glioblastoma-A Systematic Review

Simple Summary

Childhood glioblastoma is an aggressive brain tumor in children that has a very poor prognosis. Standard therapy includes surgery, irradiation and chemotherapy with temozolomide. So far, there is no effective drug treatment for pediatric glioblastoma patients. This systematic review aims to outline currently available data on novel pharmacological treatment options. None of the included phase II studies showed any benefit regarding overall survival or a prolongation of stable disease. New genomic technologies discovered the biologic heterogeneity of these tumors, demanding more individualized immunotherapeutic and targeted approaches. Autoimmune modulated therapies and further targeting of tumor-specific receptors provide promising preclinical results. Clinical trials aligned to the tumor characteristics are needed to establish effective new therapeutic approaches.

Abstract

Background: Pediatric glioblastoma (GBM) is an aggressive central nervous system tumor in children that has dismal prognosis. Standard of care is surgery with subsequent irradiation and temozolomide. We aimed to outline currently available data on novel pharmacological treatments for pediatric GBM. Methods: We conducted a systematic literature search in PubMed and Embase, including reports published in English from 2010 to 2021. We included randomized trials, cohort studies and case series. Phase I trials were not analyzed. We followed PRISMA guidelines, assessed the quality of the eligible reports using the Newcastle-Ottawa scale (NOS) and the RoB-2 tool and registered the protocol on PROSPERO. Results: We included 6 out of 1122 screened reports. All six selected reports were prospective, multicenter phase II trials (five single-arm and one randomized controlled trial). None of the investigated novel treatment modalities showed any benefit regarding overall or progression free survival. Conclusions: To date, the role of pharmacological approaches regarding pediatric GBM remains unclear, since no novel treatment approach could provide a significant impact on overall or progression free survival. Further research should aim to combine different treatment strategies in large international multicenter trials with central comprehensive diagnostics regarding subgrouping. These novel treatment approaches should include targeted and immunotherapeutic treatments, potentially leading to a more successful outcome.

The Basis and Advances in Clinical Application of Cytomegalovirus-Specific Cytotoxic T Cell Immunotherapy for Glioblastoma Multiforme

A high percentage of malignant gliomas are infected by human cytomegalovirus (HCMV), and the endogenous expression of HCMV genes and their products are found in these tumors. HCMV antigen expression and its implications in gliomagenesis have emerged as a promising target for adoptive cellular immunotherapy (ACT) strategies in glioblastoma multiforme (GB) patients. Since antigen-specific T cells in the tumor microenvironments lack efficient anti-tumor immune response due to the immunosuppressive nature of glioblastoma, CMV-specific ACT relies on in vitro expansion of CMV-specific CD8⁺ T cells employing immunodominant HCMV antigens. Given the fact that several hurdles remain to be conquered, recent clinical trials have outlined the feasibility of CMV-specific ACT prior to tumor recurrence with minimal adverse effects and a substantial improvement in median overall survival and progression-free survival. This review discusses the role of HCMV in gliomagenesis, disease prognosis, and recent breakthroughs in harnessing HCMV-induced immunogenicity in the GB tumor microenvironment to develop effective CMV-specific ACT.

Metabolic Reprogramming of Glioblastoma Cells during HCMV Infection Induces Secretome-Mediated Paracrine Effects in the Microenvironment

Glioblastoma (GBM) is an aggressive primary central nervous system neoplasia with limited therapeutic options and poor prognosis. Following reports of cytomegalovirus (HCMV) in GBM tumors, the anti-viral drug Valganciclovir was administered and found to significantly increase the longevity of GBM patients. While these findings suggest a role for HCMV in GBM, the relationship between them is not clear and remains controversial. Treatment with anti-viral drugs may prove clinically useful; however, their results do not explain the underlying mechanism between HCMV infection and GBM progression. We hypothesized that HCMV infection would metabolically reprogram GBM cells and that these changes would allow for increased tumor progression. We infected LN-18 GBM cells and employed a Seahorse Bioanalyzer to characterize cellular metabolism. Increased mitochondrial respiration and glycolytic rates were observed following infection. These changes were accompanied by elevated production of reactive oxygen species and lactate. Due to lactate’s numerous tumor-promoting effects, we examined the impact of paracrine signaling of HCMV-infected GBM cells on uninfected stromal cells. Our results indicated that, independent of viral transmission, the secretome of HCMV-infected GBM cells was able to alter the expression of key metabolic proteins and epigenetic markers. This suggests a mechanism of action where reprogramming of GBM cells alters the surrounding tumor microenvironment to be permissive to tumor progression in a manner akin to the Reverse-Warburg Effect. Overall, this suggests a potential oncomodulatory role for HCMV in the context of GBM.

Presence of the Human Cytomegalovirus in Glioblastomas-A Systematic Review

Simple Summary

Whether the human cytomegalovirus (HCMV) is present in samples obtained from patients with glioblastoma (GBM) has been a matter under debate during the last two decades. Many investigators have demonstrated the presence of HCMV proteins and nucleic acids in GBM tumors, while some have not been able to detect it. It is important to evaluate current data and resolve these issues to clarify the possible role of the HCMV in GBM tumorigenesis and if this virus can serve as a potential target of therapy for these patients. In the present systematic review, we aim to review published research studies with a focus to identify differences and similarities in methods used for the detection of the HCMV in GBM samples found to be positive or negative for HCMV. Our data suggest that the HCMV is highly prevalent in glioblastomas and that optimized immunohistochemistry techniques are required to detect it.

Abstract

Glioblastoma is a malignant brain tumor with a dismal prognosis. The standard treatment has not changed in the past 15 years as clinical trials of new treatment protocols have failed. A high prevalence of the human cytomegalovirus (HCMV) in glioblastomas was first reported in 2002. The virus was found only in the tumor and not in the surrounding healthy brain tissue. Many groups have confirmed the presence of the HCMV in glioblastomas, but others could not. To resolve this discrepancy, we systematically reviewed 645 articles identified in different databases. Of these, 81 studies included results from 247 analyses of 9444 clinical samples (7024 tumor samples and 2420 blood samples) by different techniques, and 81 articles included 191 studies that identified the HCMV in 2529 tumor samples (36% of all tumor samples). HCMV proteins were often detected, whereas HCMV nucleic acids were not reliably detected by PCR methods. Optimized immunohistochemical techniques identified the virus in 1391 (84,2%) of 1653 samples. These data suggest that the HCMV is highly prevalent in glioblastomas and that optimized immunohistochemistry techniques are required to detect it.

An efficient method to identify virus-specific TCRs for TCR-T cell immunotherapy against virus-associated malignancies

Adoptive transfer of T cells genetically engineered with a T cell receptor (TCR) is a promising cancer treatment modality that requires the identification of TCRs with good characteristics. Most T cell cloning methods involve a stringent singularization process, which necessitates either tedious hands-on operations or high cost. We present an efficient and nonstringent cloning approach based on existing techniques. We hypothesize that after elimination of most nonspecific T cells, a clonotype with high quality could outcompete other clonotypes and finally form a predominant population. This TCR identification method can be used to clone virus-specific TCRs efficiently from cancer patients and is easily adoptable by any laboratory.

Innovative and Promising Strategies to Enhance Effectiveness of Immunotherapy for CNS Tumors: Where Are We?

Although there are several immunotherapy approaches for the treatment of Central Nervous System (CNS) tumors under evaluation, currently none of these approaches have received approval from the regulatory agencies. CNS tumors, especially glioblastomas, are tumors characterized by highly immunosuppressive tumor microenvironment, limiting the possibility of effectively eliciting an immune response. Moreover, the peculiar anatomic location of these tumors poses relevant challenges in terms of safety, since uncontrolled hyper inflammation could lead to cerebral edema and cranial hypertension. The most promising strategies of immunotherapy in neuro-oncology consist of the use of autologous T cells redirected against tumor cells through chimeric antigen receptor (CAR) constructs or genetically modified T-cell receptors. Trials based on native or genetically engineered oncolytic viruses and on vaccination with tumor-associated antigen peptides are also under evaluation. Despite some sporadic complete remissions achieved in clinical trials, the outcome of patients with CNS tumors treated with different immunotherapeutic approaches remains poor. Based on the lessons learned from these unsatisfactory experiences, novel immune-therapy approaches aimed at overcoming the profound immunosuppressive microenvironment of these diseases are bringing new hope to reach the cure for CNS tumors.

Autologous CMV-specific T cells are a safe adjuvant immunotherapy for primary glioblastoma multiforme

BACKGROUNDThe recent failure of checkpoint-blockade therapies for glioblastoma multiforme (GBM) in late-phase clinical trials has directed interest toward adoptive cellular therapies (ACTs). In this open-label, first-in-human trial, we have assessed the safety and therapeutic potential of cytomegalovirus-specific (CMV-specific) ACT in an adjuvant setting for patients with primary GBM, with an ultimate goal to prevent or delay recurrence and prolong overall survival.METHODSTwenty-eight patients with primary GBM were recruited to this prospective study, 25 of whom were treated with in vitro-expanded autologous CMV-specific T cells. Participants were monitored for safety, progression-free survival, overall survival (OS), and immune reconstitution.RESULTSNo participants showed evidence of ACT-related toxicities. Of 25 evaluable participants, 10 were alive at the completion of follow-up, while 5 were disease free. Reconstitution of CMV-specific T cell immunity was evident and CMV-specific ACT may trigger a bystander effect leading to additional T cell responses to nonviral tumor-associated antigens through epitope spreading. Long-term follow-up of participants treated before recurrence showed significantly improved OS when compared with those who progressed before ACT (median 23 months, range 7-65 vs. median 14 months, range 5-19; P = 0.018). Gene expression analysis of the ACT products indicated that a favorable T cell gene signature was associated with improved long-term survival.CONCLUSIONData presented in this study demonstrate that CMV-specific ACT can be safely used as an adjuvant therapy for primary GBM and, if offered before recurrence, this therapy may improve OS of GBM patients.TRIAL REGISTRATIONanzctr.org.au: ACTRN12615000656538.FUNDINGPhilanthropic funding and the National Health and Medical Research Council (Australia).

Immune Escape in Glioblastoma Multiforme and the Adaptation of Immunotherapies for Treatment

Glioblastoma multiforme (GBM) is the most frequently occurring primary brain tumor and has a very poor prognosis, with only around 5% of patients surviving for a period of 5 years or more after diagnosis. Despite aggressive multimodal therapy, consisting mostly of a combination of surgery, radiotherapy, and temozolomide chemotherapy, tumors nearly always recur close to the site of resection. For the past 15 years, very little progress has been made with regards to improving patient survival. Although immunotherapy represents an attractive therapy modality due to the promising pre-clinical results observed, many of these potential immunotherapeutic approaches fail during clinical trials, and to date no immunotherapeutic treatments for GBM have been approved. As for many other difficult to treat cancers, GBM combines a lack of immunogenicity with few mutations and a highly immunosuppressive tumor microenvironment (TME). Unfortunately, both tumor and immune cells have been shown to contribute towards this immunosuppressive phenotype. In addition, current therapeutics also exacerbate this immunosuppression which might explain the failure of immunotherapy-based clinical trials in the GBM setting. Understanding how these mechanisms interact with one another, as well as how one can increase the anti-tumor immune response by addressing local immunosuppression will lead to better clinical results for immune-based therapeutics. Improving therapeutic delivery across the blood brain barrier also presents a challenge for immunotherapy and future therapies will need to consider this. This review highlights the immunosuppressive mechanisms employed by GBM cancers and examines potential immunotherapeutic treatments that can overcome these significant immunosuppressive hurdles.

Once, Twice, Three Times a Finding: Reproducibility of Dendritic Cell Vaccine Trials Targeting Cytomegalovirus in Glioblastoma

Despite standard of care for glioblastoma, including gross total resection, high-dose radiation, and dose-limited chemotherapy, this tumor remains one of the most aggressive and therapeutically challenging. The relatively small number of patients with this diagnosis compared with more common solid tumors in clinical trials commits new glioblastoma therapies to testing in small, underpowered, nonrandomized settings. Among approximately 200 registered glioblastoma trials identified between 2005 and 2015, nearly half were single-arm studies with sample sizes not exceeding 50 patients. These constraints have made demonstrating efficacy for novel therapies difficult in glioblastoma and other rare and aggressive cancers. Novel immunotherapies for glioblastoma such as vaccination with dendritic cells (DC) have yielded mixed results in clinical trials. To address limited numbers, we sequentially conducted three separate clinical trials utilizing cytomegalovirus (CMV)-specific DC vaccines in patients with newly diagnosed glioblastoma whereby each follow-up study had nearly doubled in sample size. Follow-up data from the first blinded, randomized phase II clinical trial (NCT00639639) revealed that nearly one third of this cohort is without tumor recurrence at 5 years from diagnosis. A second clinical trial (NCT00639639) resulted in a 36% survival rate at 5 years from diagnosis. Results of the first two-arm trial (NCT00639639) showed increased migration of the DC vaccine to draining lymph nodes, and this increased migration has been recapitulated in our larger confirmatory clinical study (NCT02366728). We have now observed that nearly one third of the glioblastoma study patient population receiving CMV-specific DC vaccines results in exceptional long-term survivors.

Virome assembly and annotation in brain tissue based on next-generation sequencing

The glioblastoma multiforme (GBM) is one of the deadliest tumors. It has been speculated that virus plays a role in GBM but the evidences are controversy. Published researches are mainly limited to studies on the presence of human cytomegalovirus (HCMV) in GBM. No comprehensive assessment of the brain virome, the collection of viral material in the brain, based on recently sequenced data has been performed. Here, we characterized the virome from 111 GBM samples and 57 normal brain samples from eight projects in the SRA database by a tested and comprehensive assembly approach. The annotation of the assembled contigs showed that most viral sequences in the brain belong to the viral family Retroviridae. In some GBM samples, we also detected full genome sequence of a novel picornavirus recently discovered in invertebrates. Unlike previous reports, our study did not detect herpes virus such as HCMV in GBM from the data we used. However, some contigs that cannot be annotated with any known genes exhibited antibody epitopes in their sequences. These findings provide several avenues for potential cancer therapy: the newly discovered picornavirus could be a starting point to engineer novel oncolytic virus; and the exhibited antibody epitopes could be a source to explore potential drug targets for immune cancer therapy. By characterizing the virosphere in GBM and normal brain at a global level, the results from this study strengthen the link between GBM and viral infection which warrants the further investigation.

Investigation of Human Cytomegalovirus and Human Papillomavirus in Glioma

The study investigated the human cytomegalovirus (HCMV) and human papillomavirus (HPV) in gliomas. A retrospective study was conducted on 112 samples. HCMV was investigated by PCR, in situ hybridization (ISH) and immunohistochemistry. HPV was tested by PCR and DNA ISH. HCMV was identified in 60 gliomas, including 55 GBM. However, RNA ISH and immunohistochemistry failed to detect HCMV positivity. HPV was identified in 44 GBM. No significant relationship was identified between HCMV and HPV and tumour characteristics (p > 0.05). Our findings support the HCMV and HPV presence in gliomas. Further assays are required to more explore the potential efficient antiviral management.

Viral infection and glioma: a meta-analysis of prognosis

Background

Glioma is the most common primary brain tumor, occurring due to the carcinogenesis of glial cells in the brain and spinal cord. Many aspects of the mechanism of its tumorigenesis remain unknown. The relationship between viral infection and glioma is one of the most important research aspects in this field. Currently, there is a lack of systematic reviews and meta-analyses to evaluate the effect of viral infection on the prognosis of glioma patients. The purpose of this study was to evaluate the relationship between viral infection and the prognosis of glioma patients, aimed at evaluating the prognostic value of the detection of viral infection.

Methods

Through careful and comprehensive retrieval of results from the PubMed, Embase, and Cochrane databases, eligible articles were selected strictly according to the inclusion and exclusion criteria. The regional sources, detection methods, detection indicators, patient survival, and other data from the samples in the papers were extracted, and the integrated analysis was conducted using Stata 15.1. We conducted a subgroup analysis of the relationship between the degree of infection and prognosis in cytomegalovirus (CMV) patients.

Results

A total of 11 studies were included in the analysis. Among them, 7 studies involved the relationship between CMV infection and the prognosis of patients with glioma, 2 studies involved human papillomavirus (HPV), 2 studies involved human herpesvirus-6 (HHV-6), and one study involved simian virus 40 (SV40), woolly monkey sarcoma virus (WMSV) and human endogenous retrovirus K113 (HERV-K113). In the CMV study, the pooled Hazard ratio (HR) of Overall survival (OS) was 1.024 (CI: 0.698–1.501), with a P value of 0.905. The pooled HR of Progression free survival (PFS) was 1.067 (CI: 0.770–1.478), with a P value of 0.697. The pooled HR value of low-degree infection versus high-degree infection was 1.476 (CI: 0.799–2.727), with a P value of 0.213. In the HPV study, the pooled HR of OS was 1.467 (CI: 0.552–3.901), with a P value of 0.443.

Conclusion

CMV infection has no significant effect on the prognosis of glioma patients. Using the IEA as the detection index, the degree of CMV infection was found to have a significant impact on the prognosis of glioma patients; it was not found to possess a significant prognostic value after the integration of different indicators. Neither HPV nor HHV-6 infection has a significant effect on the prognosis of glioma patients. SV40 and WMSV infection are associated with poor prognosis in patients with low-grade glioma.

Trial Registration

This meta-analysis registered in https://www.crd.york.ac.uk/PROSPERO/, PROSPERO ID: CRD42019127648.

Valganciclovir as Add-on to Standard Therapy in Glioblastoma Patients

PURPOSE

Several groups have reported a prevalence of human cytomegalovirus (CMV) in glioblastoma close to 100%. Previously, we reported that treatment with the antiviral drug valganciclovir as an add-on to standard therapy significantly prolonged survival in 50 patients with glioblastoma. Here, we present an updated retrospective analysis that includes an additional 52 patients.

EXPERIMENTAL DESIGN

From December 2006 to November 2019, 102 patients with newly diagnosed glioblastoma received valganciclovir as an add-on to standard therapy. No additional toxicity was observed. Contemporary controls were 231 patients with glioblastoma who received similar baseline therapy.

RESULTS

Patients with newly diagnosed glioblastoma receiving valganciclovir had longer median overall survival (OS 24.1 vs. 13.3 months, P < 0.0001) and a 2-year survival rate (49.8% vs. 17.3%) than controls. Median time-to-tumor progression was also longer than in controls; 9.9 (0.7-67.5 months) versus 7.3 (1.2-49 months), P = 0.0003. Valganciclovir improved survival in patients with radical or partial resection and an unmethylated or methylated MGMT promoter gene.

CONCLUSIONS

Valganciclovir prolonged median OS of patients with newly diagnosed glioblastoma (with methylated or unmethylated MGMT promoter gene) and was safe to use.

Human Cytomegalovirus Infection Induces High Expression of Prolactin and Prolactin Receptors in Ovarian Cancer

One of the potential biomarkers for ovarian cancer patients is high serum level of prolactin (PRL), which is a growth factor that may promote tumor cell growth. The prolactin receptor (PRLR) and human cytomegalovirus (HCMV) proteins are frequently detected in ovarian tumor tissue specimens, but the potential impact of HCMV infection on the PRL system have so far not been investigated. In this study, HCMV’s effects on PRL and PRLR expression were assessed in infected ovarian cancer cells (SKOV3) by PCR and Western blot techniques. The levels of both PRL and PRLR transcripts as well as the corresponding proteins were highly increased in HCMV-infected SKOV3 cells. Tissue specimens obtained from 10 patients with ovarian cancer demonstrated high expression of PRLR, HCMV-IE, and pp65 proteins. Extensive expression of PRLR was detected in all examined ovarian tumor tissue specimens except for one from a patient who had focal expression of PRLR and this patient was HCMV-negative in her tumor. In conclusion, PRL and PRLR were induced to high levels in HCMV-infected ovarian cancer cells and PRLR expression was extensively detected in HCMV-infected ovarian tissue specimens. Highly induced PRL and PRLR by HCMV infection may be of relevance for the oncomodulatory role of this virus in ovarian cancer.

Human cytomegalovirus infection in Iranian glioma patients correlates with aging and tumor aggressiveness

Human cytomegalovirus (HCMV), as a ubiquitous and opportunistic virus, is a matter for consideration in broad-spectrum diseases, specifically in immunocompromised individuals. In recent decades, many studies that have evaluated the role of HCMV in inflammation and malignancies, especially in high-grade gliomas, have reported inconsistent results. Thus, this study was conducted to analyze 97 primary gliomas for human CMV UL83 gene and protein through TaqMan real-time polymerase chain reaction and immunohistochemistry, respectively. The results were positive for the UL83 gene and pp65 protein in 71% and 24% of samples, respectively. The frequency of HCMV was significantly higher in glioblastomas than other glioma grades (P < .01 and P < .05 for the UL83 gene and protein, respectively). In addition, the association between the prevalence of HCMV and aging strengthened the virus reactivation hypothesis in gliomas. In conclusion, a high frequency of HCMV infection was found in gliomas that correlated with tumor aggressiveness and age. This study recommends a thorough investigation to determine HCMV infection in gliomas to improve the existing knowledge of its role in glial tumors, its prognostic value, and possible efficient antiviral target therapy.

Human cytomegalovirus seropositivity is associated with decreased survival in glioblastoma patients

Background

Human cytomegalovirus (HCMV) is an oncomodulatory human herpesvirus that has been detected in glioblastoma (GBM) and is associated with worse prognosis in patients with the disease. The effects of HCMV systemic infection on survival in GBM patients, however, are largely unknown. We aimed to determine the association between HCMV serostatus at diagnosis and survival via a retrospective cohort study of GBM patients.

Methods

Plasma from 188 GBM patients treated at the Ben and Catherine Ivy Center (Seattle, WA) was tested for HCMV serostatus via enzyme-linked immunosorbent assays of anti-HCMV immunoglobulin (Ig)G. HCMV IgG serostatus was analyzed with respect to each patient’s progression-free and overall survival (OS) via log-rank and multivariable Cox regression analysis.

Results

Ninety-seven of 188 (52%) patients were anti-HCMV IgG seropositive. Median OS was decreased in the IgG+ cohort (404 days) compared to IgG− patients (530 days; P = .0271). Among O⁶-methylguanine-DNA methyltransferase (MGMT) unmethylated patients (n = 96), median OS was significantly decreased in IgG+ patients (336 days) compared to IgG− patients (510 days; P = .0094). MGMT methylation was associated with improved OS in IgG+ patients versus those who were unmethylated (680 vs 336 days; P = .0096), whereas no such association was observed among IgG− patients.

Conclusions

In this study, HCMV seropositivity was significantly associated with poorer OS in GBM patients. This finding suggests prior infection with HCMV may play an important role in GBM patient outcomes, and anti-HCMV antibodies may, therefore, prove a valuable prognostic tool in the management of GBM patients.

Is the presence of HCMV components in CNS tumors a glioma-specific phenomenon?

Background

Human cytomegalovirus (HCMV) has been associated with malignant gliomas. The purpose of the present study was to investigate the presence of HCMV in common non-glial tumors of the central nervous system (CNS) and to determine whether it is a glioma-specific phenomenon.

Methods

Using HCMV-specific immunohistochemical staining, HCMV proteins IE1–72 and pp65 were examined in 65 meningiomas (benign, atypical and malignant), 45 pituitary adenomas, 20 cavernous hemangiomas, and 30 metastatic carcinomas specimens. HCMV DNA was also measured in these tumor tissues and the peripheral blood from patients using nested PCR.

Results

In meningioma, IE1–72 was detected in 3.1% (2/65) and pp65 was detected in 4.6% (3/65), whereas no IE1–72 and pp65 were detected in atypical and malignant meningioma. A low level of IE1–72 immunoreactivity 6.7% (2/30) was detected in metastatic carcinoma; pp65 was not detected. No HCMV components were detected in pituitary adenoma and cavernous hemangioma. The results of immunohistochemical staining were confirmed by HCMV-specific PCR. HCMV DNA was not detected in the peripheral blood of the non-glial CNS tumors patients.

Conclusions

Our results demonstrate that the presence of HCMV components is not an entirely glioma-specific phenomenon, and that HCMV is present in a low percentage in some non-glioma CNS tumors. Comparing HCMV-positive non-glial CNS tumors with HCMV-positive gliomas may cast light on the mechanism and role of HCMV in CNS tumors.

Electronic supplementary material

The online version of this article (10.1186/s12985-019-1198-5) contains supplementary material, which is available to authorized users.

Human Cytomegalovirus DNA among Women with Breast Cancer

Section Title

Breast cancer is the most common cause of death among women worldwide. Although there are many known risk factors in breast cancer development, infectious diseases have appeared as one of the important key to contribute to carcinogenesis formation. The effects of Human Cytomegalovirus (HCMV) on women with breast cancer has been recently studied and reported. To contribute to this research trend, this study was conducted to evaluate the association between HCMV and the women with breast cancer.

Objective:

This experiment aimed to evaluate HCMV DNA in women with breast cancer in Ahvaz city, Iran.

Materials and Methods:

A total of 37 formalin fixed paraffin embedded tissues of the patients with ductal breast carcinoma and 35 paraffin embedded tissues of the patients with fibro adenoma as control group were collected. The deparaffinization of all the samples were carried out and the DNA was extracted. Initially, the PCR test was carried out to detect beta –globulin DNA as an internal control. For those samples positive for beta –globulin DNA, Polymerase Chain reaction (PCR) was used to detect HCMV for the tests and control samples.

Results:

Among 37 ductal breast carcinoma, 20 (54.04%) cases were proved positive for HCMV DNA by PCR. While among the 35 control group (fibroadenoma), 10 (28.57%) cases were positive for HCMV DNA (P >0.028). The prevalences of HCMV DNA among the age groups 30-39, 40-49 and >50 years were 7 (72.22%), 9 (69.23%), 4 (57.14%), respectively (P=0.066). A high frequency of HCMV DNA was detected in tumor grade III, 13/18 (58.33%) compared with tumor grade II, 7/19 (36.84%) (p=0.044). A high frequency of 16/24 (66.66%) of HCMV DNA was found in invasive ductal breast cancer compared with 4/13 (30.76%) HCMV DNA in situ (P<0.028).

Conclusion:

A high prevalence of 54.05% HCMV was found among the patients with ductal carcinoma. The percentages of the high prevalence of HCMV among age group (40-49) years, tumors grades, and invasive stage were (69.23%), (58.33%), (66.66%), respectively. Further study of HCMV in the latency phase in patients with ductal carcinoma would be necessary to extend our knowledge.

Development of a Human Cytomegalovirus (HCMV)-Based Therapeutic Cancer Vaccine Uncovers a Previously Unsuspected Viral Block of MHC Class I Antigen Presentation

Human cytomegalovirus (HCMV) induces a uniquely high frequency of virus-specific effector/memory CD8+ T-cells, a phenomenon termed “memory inflation”. Thus, HCMV-based vaccines are particularly interesting in order to stimulate a sustained and strong cellular immune response against cancer. Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor with high lethality and inevitable relapse. The current standard treatment does not significantly improve the desperate situation underlining the urgent need to develop novel approaches. Although HCMV is highly fastidious with regard to species and cell type, GBM cell lines are susceptible to HCMV. In order to generate HCMV-based therapeutic vaccine candidates, we deleted all HCMV-encoded proteins (immunoevasins) that interfere with MHC class I presentation. The aim being to use the viral vector as an adjuvant for presentation of endogenous tumor antigens, the presentation of high levels of vector-encoded neoantigens and finally the repurposing of bystander HCMV-specific CD8+ T cells to fight the tumor. As neoantigen, we exemplarily used the E6 and E7 proteins of human papillomavirus type 16 (HPV-16) as a non-transforming fusion protein (E6/E7) that covers all relevant antigenic peptides. Surprisingly, GBM cells infected with E6/E7-expressing HCMV-vectors failed to stimulate E6-specific T cells despite high level expression of E6/E7 protein. Further experiments revealed that MHC class I presentation of E6/E7 is impaired by the HCMV-vector although it lacks all known immunoevasins. We also generated HCMV-based vectors that express E6-derived peptide fused to HCMV proteins. GBM cells infected with these vectors efficiently stimulated E6-specific T cells. Thus, fusion of antigenic sequences to HCMV proteins is required for efficient presentation via MHC class I molecules during infection. Taken together, these results provide the preclinical basis for development of HCMV-based vaccines and also reveal a novel HCMV-encoded block of MHC class I presentation.

Human cytomegalovirus infection is correlated with enhanced cyclooxygenase-2 and 5-lipoxygenase protein expression in breast cancer

Purpose

While enhanced expression of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) and their derived metabolites is associated with breast cancer (BC) risk, the precise link between BC carcinogenesis and enhanced inflammatory activity remains to be clarified. Human Cytomegalovirus (HCMV) may induce expression of COX-2 and 5-LO and is frequently found in breast cancer biopsies. Thus, we investigated whether there is an association between HCMV proteins and expression of COX-2 and 5-LO in human BC tissue and BC cell lines.

Materials and methods

Paraffin embedded biopsies obtained from 49 patients with breast cancer and 26 tissue samples from adjacent, benign breast tissues were retrospectively examined for HCMV-immediate early (IE), HCMV-Late (LA), COX-2, and 5-LO proteins by immunohistochemistry. In vitro, uninfected and HCMV-infected BC cell lines were examined for COX-2 and 5-LO transcripts and proteins by PCR and flow cytometry.

Results

Extensive expression of COX-2, 5-LO and HCMV-IE proteins were preferentially detected in BC samples. We found a statistically significant concordant correlation between extensive HCMV-IE and COX-2 (P < 0.0001) as well as with HCMV-IE and 5-LO (P = 0.0003) in infiltrating BC. In vitro, HCMV infection induced COX-2 and 5-LO transcripts and COX-2 proteins in MCF-7 cells (P =0.008, P =0.018, respectively). In MDA-MB-231 cells that already had high base line levels of COX-2 expression, HCMV induced both COX-2 and 5-LO proteins but not transcripts.

Conclusion

Our findings demonstrate a significant correlation between extensive HCMV-IE protein expression and overexpression of COX-2 and 5-LO in human breast cancer.

Electronic supplementary material

The online version of this article (10.1007/s00432-019-02946-8) contains supplementary material, which is available to authorized users.

Cytomegalovirus promotes murine glioblastoma growth via pericyte recruitment and angiogenesis

Cytomegalovirus (CMV) has been implicated in glioblastoma (GBM); however, a mechanistic connection in vivo has not been established. The purpose of this study is to characterize the effects of murine CMV (MCMV) on GBM growth in murine models. Syngeneic GBM models were established in mice perinatally infected with MCMV. We found that tumor growth was markedly enhanced in MCMV+ mice, with a significant reduction in overall survival compared with that of controls (P < 0.001). We observed increased angiogenesis and tumor blood flow in MCMV+ mice. MCMV reactivation was observed in intratumoral perivascular pericytes and tumor cells in mouse and human GBM specimens, and pericyte coverage of tumor vasculature was strikingly augmented in MCMV+ mice. We identified PDGF-D as a CMV-induced factor essential for pericyte recruitment, angiogenesis, and tumor growth. The antiviral drug cidofovir improved survival in MCMV+ mice, inhibiting MCMV reactivation, PDGF-D expression, pericyte recruitment, and tumor angiogenesis. These data show that MCMV potentiates GBM growth in vivo by increased pericyte recruitment and angiogenesis due to alterations in the secretome of CMV-infected cells. Our model provides evidence for a role of CMV in GBM growth and supports the application of antiviral approaches for GBM therapy.

Immunotherapy for Glioblastoma: Adoptive T-cell Strategies

Glioblastoma (GBM) is a devastating disease with an extremely poor prognosis. Immunotherapy via adoptive cell transfer (ACT), especially with T cells engineered to express chimeric antigen receptors (CAR), represents a particularly promising approach. Despite the recent success of CAR T cells for blood cancers, the question remains whether this powerful anticancer therapy will ultimately work for brain tumors, and whether the primary immunologic challenges in this disease, which include antigenic heterogeneity, immune suppression, and T-cell exhaustion, can be adequately addressed. Here, we contextualize these concepts by reviewing recent developments in ACT for GBM, with a special focus on pioneering clinical trials of CAR T-cell therapy.

The role of CMV in glioblastoma and implications for immunotherapeutic strategies

Controversy surrounds the role of cytomegalovirus (CMV) in glioblastoma (GBM). However, several studies have shown that CMV nucleic acids and proteins are present within GBM tumor tissue. CMV has been implicated in GBM pathogenesis by affecting tumor stem cell factors, angiogenesis and immune pathways. Anti-viral therapy has not been found to definitively improve outcomes for patients with GBM. Several studies have leveraged CMV by targeting CMV antigens using ex-vivo expanded T cells or dendritic cell vaccines. The initial results from these studies are promising and larger studies are underway.

Human Cytomegalovirus is Present in Alveolar Soft Part Sarcoma

Alveolar soft part sarcoma (ASPS) is an exquisitely rare sarcoma of unknown histogenesis, with a predilection for adolescents and young adults, characterized by slow progressive clinical course and high frequency of metastases. They are traditionally chemoresistant with very limited treatment options in the metastatic setting. Human cytomegalovirus (HCMV) is a DNA β-herpes virus and it is characterized by persistent lifelong and latent infection. There is growing evidence to indicate the presence of HCMV proteins and nucleic acids in glioblastoma, medulloblastoma, rhabdomyosarcoma, and a variety of solid organ malignancies of the breast, prostate, lung, and colon at very high prevalence. Immunotherapy-based clinical trials targeting specific cytomegalovirus proteins are currently in progress in the treatment of glioblastoma. Herein, we evaluated for the presence of HCMV proteins (IE1 and pp65), genes (US28 and UL96), and RNA in a cohort of ASPS. Six confirmed cases of ASPS were retrieved and full thickness sections of formalin-fixed paraffin-embedded material were stained for anti-HMCV-IE1 and anti-HCMV-pp65. Any nuclear and/or cytoplasmic staining was considered positive. DNA was purified from 50 µm of formalin-fixed paraffin-embedded material. One hundred nanogram of DNA was amplified using polymerase chain reaction for primers specific to HCMV-US28 (forward: AGCGTGCCGTGTACGTTAC and reverse: ATAAAGACAAGCACGACC) and HCMV-UL96 (forward: ACAGCTCTTAAAGGACGTGATGCG and reverse: ACCGTGTCCTTCAGCTCGGTTAAA) using Promega Taq polymerase. HCMV in situ hybridization was performed. All 6 cases of ASPS were positive for both HCMV-IE1 and HCMV-pp65. Usable DNA was available in 4 of the 6 cases. HCMV-US28 gene was found in 75% (3/4) of cases and HCMV-UL96 gene was detected in 50% (2/4) of cases. Importantly, all cases tested positive for at least 1 gene. HCMV-encoded RNA was identified in 80% (4/5) of cases. The presence of HCMV DNA, RNA along with HCMV protein indicates that HCMV is present in ASPS and may contribute to its pathogenesis.

CAR T-cell therapy for glioblastoma: ready for the next round of clinical testing?

INTRODUCTION

The outcome for patients with glioblastoma (GBM) remains poor, and there is an urgent need to develop novel therapeutic approaches. T cells genetically modified with chimeric antigen receptors (CARs) hold the promise to improve outcomes since they recognize and kill cells through different mechanisms than conventional therapeutics. Areas covered: This article reviews CAR design, tumor associated antigens expressed by GBMs that can be targeted with CAR T cells, preclinical and clinical studies conducted with CAR T cells, and genetic approaches to enhance their effector function. Expert commentary: While preclinical studies have highlighted the potent anti-GBM activity of CAR T cells, the initial foray of CAR T-cell therapies into the clinic resulted only in limited benefits for GBM patients. Additional genetic modification of CAR T cells has resulted in a significant increase in their anti-GBM activity in preclinical models. We are optimistic that clinical testing of these enhanced CAR T cells will be safe and result in improved anti-glioma activity in GBM patients.

Quo Vadis-Do Immunotherapies Have a Role in Glioblastoma?

PURPOSE OF REVIEW

More effective therapies for glioblastoma are urgently needed. Immunotherapeutic strategies appear particularly promising and are therefore intensively studied. This article reviews the current understanding of the immunosuppressive glioblastoma microenvironment, discusses the rationale behind various immunotherapies, and outlines the findings of several recently published clinical studies.

RECENT FINDINGS

The results of CheckMate-143 indicated that nivolumab is not superior to bevacizumab in patients with recurrent glioblastoma. A first-in man exploratory study evaluating EGFRvIII-specific CAR T cells for patients with newly diagnosed glioblastoma demonstrated overall safety of CAR T cell therapy and effective target recognition. A pilot study evaluating treatment with adoptively transferred CMV-specific T cells combined with a CMV-specific DC vaccine was found to be safe and resulted in increased polyclonality of CMV-specific T cells in vivo. Despite the success of immunotherapies in many cancers, clinical evidence supporting their efficacy for patients with glioblastoma is still lacking. Nevertheless, the recently published studies provide important proof-of-concept in several areas of immunotherapy research. The careful and critical interpretation of these results will enhance our understanding of the opportunities and challenges of immunotherapies for high-grade gliomas and improve the immunotherapeutic strategies investigated in future clinical trials.

New extracellular factors in glioblastoma multiforme development: neurotensin, growth differentiation factor-15, sphingosine-1-phosphate and cytomegalovirus infection

Recent years have seen considerable progress in understanding the biochemistry of cancer. For example, more significance is now assigned to the tumor microenvironment, especially with regard to intercellular signaling in the tumor niche which depends on many factors secreted by tumor cells. In addition, great progress has been made in understanding the influence of factors such as neurotensin, growth differentiation factor-15 (GDF-15), sphingosine-1-phosphate (S1P), and infection with cytomegalovirus (CMV) on the 'hallmarks of cancer' in glioblastoma multiforme. Therefore, in the present work we describe the influence of these factors on the proliferation and apoptosis of neoplastic cells, cancer stem cells, angiogenesis, migration and invasion, and cancer immune evasion in a glioblastoma multiforme tumor. In particular, we discuss the effect of neurotensin, GDF-15, S1P (including the drug FTY720), and infection with CMV on tumor-associated macrophages (TAM), microglial cells, neutrophil and regulatory T cells (T_reg), on the tumor microenvironment. In order to better understand the role of the aforementioned factors in tumoral processes, we outline the latest models of intratumoral heterogeneity in glioblastoma multiforme. Based on the most recent reports, we discuss the problems of multi-drug therapy in treating glioblastoma multiforme.

Lack of cytomegalovirus detection in human glioma

Gliomas are the most common brain tumors and include a variety of histologic types and grades of malignancy. They arise from glial cells and represent approximately 70% of the primary brain tumors. According to the criteria of the World Health Organization (WHO), the majority of gliomas can be classified into four grades of malignancy (I-IV). Virus infection, especially by DNA viruses and retroviruses, which may cause insertion of viral DNA sequences into the host genome, often triggers the host defense mechanisms. Particularly, the DNA methylation machinery can be activated to cause the methylation of foreign movable viral sequences and, therefore, silence viral gene expression. Several studies have shown the presence of Human Cytomegalovirus (HCMV) in glioblastoma, suggesting that the virus may participate in tumor pathogenesis. But this relationship is controversial because many other studies did not detect HCMV in these tumors. This study aims to detect the presence of HCMV in several samples of human glioma (94 formalin-fixed, paraffin-embedded samples and 28 snap-frozen samples) by different sensitive techniques. We have been unable to detect HCMV DNA and proteins in glioma samples. Therefore, arguments used so far to conclude that HCMV is an oncomodulator virus in gliomas must be, in our view, seriously reconsidered.

Surrogate in vitro activation of innate immunity synergizes with interleukin-7 to unleash rapid antigen-driven outgrowth of CD4+ and CD8+ human peripheral blood T-cells naturally recognizing MUC1, HER2/neu and other tumor-associated antigens

Effective adoptive immunotherapy has proved elusive for many types of human cancer, often due to difficulties achieving robust expansion of natural tumor-specific T-cells from peripheral blood. We hypothesized that antigen-driven T-cell expansion might best be triggered in vitro by acute activation of innate immunity to mimic a life-threatening infection. Unfractionated peripheral blood mononuclear cells (PBMC) were subjected to a two-step culture, first synchronizing their exposure to exogenous antigens with aggressive surrogate activation of innate immunity, followed by γ-chain cytokine-modulated T-cell hyperexpansion. Step 1 exposure to GM-CSF plus paired Toll-like receptor agonists (resiquimod and LPS), stimulated abundant IL-12 and IL-23 secretion, as well as upregulated co-stimulatory molecules and CD11c expression within the myeloid (CD33+) subpopulation. Added synthetic long peptides (>20aa) derived from widely expressed oncoproteins (MUC1, HER2/neu and CMVpp65), were reliably presented to CD4+ T-cells and cross-presented to CD8+ T-cells. Both presentation and cross-presentation demonstrated proteasomal and Sec61 dependence that could bypass the endoplasmic reticulum. Step 2 exposure to exogenous IL-7 or IL-7+IL-2 produced selective and sustained expansion of both CD4+ and CD8+ peptide-specific T-cells with a predominant interferon-γ-producing T1-type, as well as the antigen-specific ability to lyse tumor targets. Other γ-chain cytokines and/or combinations were initially proliferogenic, but followed by a contractile phase not observed with IL-7 or IL-7+IL-2. Regulatory T-cells were minimally propagated under these culture conditions. This mechanistically rational culture sequence, effective even for unvaccinated donors, enables rapid preparation of T-cells recognizing tumor-associated antigens expressed by the majority of human cancers, including pancreatic cancers, breast cancers and glioblastomas.

Detection of human cytomegalovirus in glioblastoma among Taiwanese subjects

The relationship between human cytomegalovirus (HCMV) and glioblastoma (GBM) has been debated for more than a decade. We investigated the presence of HCMV genes, RNA and protein in GBMs and their relationships with tumor progression. Results of quantitative PCR for HCMV UL73, nested PCR for HCMV UL144, in situ hybridization (ISH) for RNA transcript, and immunohistochemistry (IHC) for protein expression and their relationship to the prognosis of 116 patients with GBM were evaluated. Nine (7.8%) cases revealed a low concentration of HCMV UL73, and only 2 of the 9 (1.7%) cases showed consistent positivity on repeat PCR testing. HCMV UL144, ISH and IHC assays were all negative. The HCMV UL73 positive cases did not show significant difference in the clinicopathological characters including age, gender, Karnofsky performance status, extent of resection, bevacizumab treatment, isocitrate dehydrogenase 1 mutation, O⁶-methylguanine-DNA-methyltranferase status and Ki67 labeling index, and did not reveal prognostic significance. As only one HCMV gene was detected at low concentration in 7.8% of GBMs and there was no evidence of transcription, protein expression or prognostic impact, we cannot conclude a relationship between HCMV and GBM in Taiwanese patients.

Human cytomegalovirus-mediated immunomodulation: Effects on glioblastoma progression

The presence of human cytomegalovirus (HCMV) and glioblastoma multiforme (GBM), first established in 2002, has developed into an area of considerable interest and controversy. Numerous studies have found evidence of possible HCMV infection of GBM tumor cells as well as myriad onco- and immunomodulatory properties exhibited by HCMV antigens and transcripts, while recent reports have failed to detect HCMV particles in GBM and question the virus' role in tumor progression. This review highlights the known immunomodulatory properties of HCMV, independent of GBM infection status, that help drive the virus from peripheral blood into the vital tissues and subsequently dampen local immune response, assisting GBM tumors in evading immune surveillance and contributing to the disease's poor prognosis. Emerging antiviral approaches to treating GBM, including antiviral drugs and immunotherapies directed against HCMV, are also examined.

History and current state of immunotherapy in glioma and brain metastasis

Malignant brain tumors such as glioblastoma (GBM) and brain metastasis have poor prognosis despite conventional therapies. Successful use of vaccines and checkpoint inhibitors in systemic malignancy has increased the hope that immune therapies could improve survival in patients with brain tumors. Manipulating the immune system to fight malignancy has a long history of both modest breakthroughs and pitfalls that should be considered when applying the current immunotherapy approaches to patients with brain tumors. Therapeutic vaccine trials for GBM date back to the mid 1900s and have taken many forms; from irradiated tumor lysate to cell transfer therapies and peptide vaccines. These therapies were generally well tolerated without significant autoimmune toxicity, however also did not demonstrate significant clinical benefit. In contrast, the newer checkpoint inhibitors have demonstrated durable benefit in some metastatic malignancies, accompanied by significant autoimmune toxicity. While this toxicity was not unexpected, it exceeded what was predicted from pre-clinical studies and in many ways was similar to the prior trials of immunostimulants. This review will discuss the history of these studies and demonstrate that the future use of immune therapy for brain tumors will likely need a personalized approach that balances autoimmune toxicity with the opportunity for significant survival benefit.

Association of Human Cytomegalovirus with Hodgkin’s Disease and Non-Hodgkin’s lymphomas

Background and Objective:

The human cytomegalovirus (HCMV) can persist lifelong as a latent infection and may result in a series of disorders. Associations with both Hodgkin’s disease and non-Hodgkin´s lymphomas have been reported. Expression of the unique long (UL)138 gene of HCMV is linked with the viral latency phase while that of the immediate-early (IE)1 gene is typical of the viral replication phase in patients. This study conducted to determine the prevalence of CMV latent infection in histological tissue samples from patients with Hodgkin’s and Non-Hodgkin´s lymphomas.

Material and Methods:

A cross sectional study was carried out with a total of 50 paraffin embedded tissues blocks, including 25 samples for Hodgkin’s disease and 25 samples for non-Hodgkin´s lymphomas. After RNA extraction and cDNA preparation, detection of IE1 mRNA was conducted by RT-PCR and identification of mRNA UL138 was achieved by nested PCR.

Results:

Among 25 cases of Non-Hodgkin´s lymphoma, 5 (20%) were positive for UL 138 and 1 (4%) for both IE1 and UL 138. Among 25 cases of Hodgkin only 1 (4%) was positive for UL 138 and all were negative for IE1

Conclusion:

A relatively high 20% rate of expression of UL 138 was detected in patients with non-Hodgkin´s lymphoma, so that latent CMV infection may play a role in development of the disease.

The Viral Connection to Glioblastoma

PURPOSE OF REVIEW

The high incidence of and mortality from glioblastoma are matched by a lack of effective therapies. Previous research suggests an association between viral infection and glioma formation. In this manuscript, we review the available evidence for this association and the efficacy of treatment strategies targeted against viral infection.

RECENT FINDINGS

We find that while a wide array of viruses can drive glioma tumor formation in vitro and in xenograft models, the most convincing association is with the human Cytomegalovirus (HCMV). Detection of HCMV in glioblastoma resected from living patients suggests it may either drive gliomagenesis, support tumor growth, or reactivate silently in these tumors. However, there is conflicting evidence on its ubiquity and its role in tumor formation. Valganciclovir may extend survival in glioblastoma patients, though adequate data on its efficacy and mechanism of action are lacking. Immunotherapy provides the opportunity to specifically target the virus and possibly, glioblastoma, though there are no large, randomized trials testing its efficacy to date. Overall, despite mounting evidence for an association between HCMV and glioblastoma, its role as an oncogenic factor and a therapeutic target remains controversial.

The Safety of available immunotherapy for the treatment of glioblastoma

INTRODUCTION

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. Current standard of care involves maximal surgical resection combined with adjuvant chemoradiation. Growing support exists for a role of immunotherapy in treating these tumors with the goal of targeted cytotoxicity. Here we review data on the safety for current immunotherapies being tested in GBM. Areas covered: Safety data from published clinical trials, including ongoing clinical trials were reviewed. Immunotherapeutic classes currently under investigation in GBM include various vaccination strategies, adoptive T cell immunotherapy, immune checkpoint blockade, monoclonal antibodies, and cytokine therapies. Trials include children, adolescents, and adults with either primary or recurrent GBM. Expert opinion: Based on the reviewed clinical trials, the current immunotherapies targeting GBM are safe and well-tolerated with minimal toxicities which should be noted. However, the gains in patient survival have been modest. A safe and well-tolerated combinatory immunotherapeutic approach may be essential for optimal efficacy towards GBM.

Increased infiltration and tolerised antigen-specific CD8+ TEM cells in tumor but not peripheral blood have no impact on survival of HCMV+ glioblastoma patients

Human cytomegalovirus (HCMV) antigens in glioblastoma (GBM) present opportunities for personalised immunotherapy. However, their presence in GBM tissue is still under debate, and evidence of their impact on functional immune responses and prognosis is sparse. Here, we investigated the presence of pp65 (UL83) and immediate early 1 (IE-1) HCMV antigens in a cohort of Norwegian GBM patients (n = 177), using qPCR, immunohistochemistry, and serology. HCMV status was then used to investigate whether viral antigens influenced immune cell phenotype, infiltration, activation and patient survival. Pp65 and IE-1 were detected by qPCR in 23% and 43% of GBM patients, respectively. Furthermore, there was increased seropositivity in GBM patients relative to donors (79% vs. 48%, respectively; Logistic regression, OR = 4.05, 95%CI [1.807-9.114], P = 0.001, also when adjusted for age (OR = 2.84, 95%CI [1.110-7.275], P = 0.029). Tissue IE-1-positivity correlated with increased CD3⁺CD8⁺ T-cell infiltration (P < 0.0001), where CD8⁺ effector memory T (T_EM) cells accounted for the majority of CD8⁺T cells compared with peripheral blood of HCMV⁺ patients (P < 0.0001), and HCMV⁺ (P < 0.001) and HCMV^- (P < 0.001) donors. HLA-A2/B8-restricted HCMV-specific CD8⁺ T cells were more frequent in blood and tumor of HCMV⁺ GBM patients compared with seronegative patients, and donors irrespective of their serostatus. In biopsies, the HCMV-specific CD8⁺ T_EM cells highly expressed CTLA-4 and PD-1 immune checkpoint protein markers compared with populations in peripheral blood (P < 0.001 and P < 0.0001), which expressed 3-fold greater levels of CD28 (P < 0.001 and P < 0.0001). These peripheral blood T cells correspondingly secreted higher levels of IFNγ in response to pp65 and IE-1 peptide stimulation (P < 0.001). Thus, despite apparent increased immunogenicity of HCMV compared with tumor antigens, the T cells were tolerised, and HCMV status did not impact patient survival (Log Rank_3.53 HR = 0.85 95%CI [0.564-1.290], P = 0.45). Enhancing immune functionality in the tumor microenvironment thus may improve patient outcome.