Cytomegalovirus infection of glioblastoma cells leads to NF-κB dependent upregulation of the c-MET oncogenic tyrosine kinase

Cytomegalovirus (CMV) is widespread in humans and has been implicated in glioblastoma (GBM) and other tumors. However, the role of CMV in GBM remains poorly understood and the mechanisms involved are not well-defined. The goal of this study was to identify candidate pathways relevant to GBM that may be modulated by CMV. Analysis of RNAseq data after CMV infection of patient-derived GBM cells showed significant upregulation of GBM-associated transcripts including the MET oncogene, which is known to play a role in a subset of GBM patients. These findings were validated in vitro in both mouse and human GBM cells. Using immunostaining and RT-PCR in vivo, we confirmed c-MET upregulation in a mouse model of CMV-driven GBM progression and in human GBM. siRNA knockdown showed that MET upregulation was dependent on CMV-induced upregulation of NF-κB signaling. Finally, proneural GBM xenografts overexpressing c-MET grew much faster in vivo than controls, suggesting a mechanism by which CMV infection of tumor cells could induce a more aggressive mesenchymal phenotype. These studies implicate the CMV-induced upregulation of c-MET as a potential mechanism involved in the effects of CMV on GBM growth.

Systemic administration of mesenchymal stem cells loaded with a novel oncolytic adenovirus carrying IL-24/endostatin enhances glioma therapy

Oncolytic adenovirus-mediated gene therapy shows promise for cancer treatment; however, the systemic delivery of oncolytic adenovirus to tumors remains challenging. Recently, mesenchymal stem cells (MSCs) have emerged as potential vehicles for improving delivery. Yet, because the oncolytic adenovirus replicates in MSCs, balancing MSC viability with viral load is key to achieving optimal therapeutic effect. We thus developed an all-in-one Tet-on system that can regulate replication of oncolytic adenovirus. Then, we loaded the novel oncolytic adenovirus carrying interleukin (IL)-24 and/or Endostatin in human umbilical cord blood-mesenchymal stem cells (hUCB-MSCs) for glioma therapy. In vitro assays demonstrated that this novel oncolytic adenovirus could efficiently replicate and kill glioma cells while sparing normal cells. Moreover, doxycycline effectively regulated oncolytic adenovirus replication in the hUCB-MSCs. The doxycycline induction group with dual expression of IL-24 and Endostatin exhibited significantly greater antitumor effects than other groups in a xenograft model of glioma. Thus, this strategy for systemic delivery of oncolytic adenovirus with its oncolytic activity controlled by a Tet-on system is a promising method for achieving antitumor efficacy in glioma, especially for metastatic tumors.

Oncolytic adenovirus and gene therapy with EphA2-BiTE for the treatment of pediatric high-grade gliomas

BACKGROUND

Pediatric high-grade gliomas (pHGGs) are among the most common and incurable malignant neoplasms of childhood. Despite aggressive, multimodal treatment, the outcome of children with high-grade gliomas has not significantly improved over the past decades, prompting the development of innovative approaches.

METHODS

To develop an effective treatment, we aimed at improving the suboptimal antitumor efficacy of oncolytic adenoviruses (OAs) by testing the combination with a gene-therapy approach using a bispecific T-cell engager (BiTE) directed towards the erythropoietin-producing human hepatocellular carcinoma A2 receptor (EphA2), conveyed by a replication-incompetent adenoviral vector (EphA2 adenovirus (EAd)). The combinatorial approach was tested in vitro, in vivo and thoroughly characterized at a molecular level.

RESULTS

After confirming the relevance of EphA2 as target in pHGGs, documenting a significant correlation with worse clinical outcome of the patients, we showed that the proposed strategy provides significant EphA2-BiTE amplification and enhanced tumor cell apoptosis, on coculture with T cells. Moreover, T-cell activation through an agonistic anti-CD28 antibody further increased the activation/proliferation profiles and functional response against infected tumor cells, inducing eradication of highly resistant, primary pHGG cells. The gene-expression analysis of tumor cells and T cells, after coculture, revealed the importance of both EphA2-BiTE and costimulation in the proposed system. These in vitro observations translated into significant tumor control in vivo, in both subcutaneous and a more challenging orthotopic model.

CONCLUSIONS

The combination of OA and EphA2-BiTE gene therapy strongly enhances the antitumor activity of OA, inducing the eradication of highly resistant tumor cells, thus supporting the clinical translation of the approach.

Induction of Brain Tumors by the Archetype Strain of Human Neurotropic JCPyV in a Transgenic Mouse Model

JC Virus (JCPyV), a member of the Polyomaviridiæ family, is a human neurotropic virus with world-wide distribution. JCPyV is the established opportunistic infectious agent of progressive multifocal leukoencephalopathy, a fatal demyelinating disease, which results from the cytolytic infection of oligodendrocytes. Mutations in the regulatory region of JCPyV determine the different viral strains. Mad-1 the strain associated with PML contains two 98 base pair repeats, whereas the archetype strain (CY), which is the transmissible form of JCPyV, contains only one 98 tandem with two insertions of 62 and 23 base pairs respectively. The oncogenicity of JCPyV has been suspected since direct inoculation into the brain of rodents and primates resulted in the development of brain tumors and has been attributed to the viral protein, T-Antigen. To further understand the oncogenicity of JCPyV, a transgenic mouse colony containing the early region of the archetype strain (CY), under the regulation of its own promoter was generated. These transgenic animals developed tumors of neural crest origin, including: primitive neuroectodermal tumors, medulloblastomas, adrenal neuroblastomas, pituitary tumors, malignant peripheral nerve sheath tumors, and glioblastomas. Neoplastic cells from all different phenotypes express T-Antigen. The close parallels between the tumors developed by these transgenic animals and human CNS tumors make this animal model an excellent tool for the study of viral oncogenesis.

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.

How we treat patients with brain tumour during the COVID-19 pandemic

The COVID-19 pandemic has created major insecurities regarding whether we can and should maintain the current standards of diagnosis and treatment and access to care for patients with cancer. This is particularly true in the field of neuro-oncology, where the perceived benefit of therapeutic interventions is often low, although this notion is partially incorrect. We acknowledge that the recommendations for care of patients with cancer have become a moving target and that all recommendations are subject to modification based on national and institutional regulations. Still, some important considerations and proposals may apply broadly. First, it is important to note that old age and cardiovascular and pulmonary co-morbidities are the major risk factors for experiencing a severe course of and for dying of COVID-19, not chronic immunosuppression and cancer. Second, many of the considerations on how we should adapt clinical practice in neuro-oncology in view of COVID-19 that are now dominating discussions at local tumour boards, as well as on the institutional level and within societies of neuro-oncology, are not novel but have been valid before and only now have become a priority. More than ever, it seems to be mandatory to adhere to evidence-based medicine and not to prescribe potentially toxic, notably immunsuppresssive systemic therapy where evidence for efficacy is low. Furthermore, it is more obvious now that oncologists must not miss the right time for advance care planning, that is, supporting patients in understanding and sharing their personal values, life goals and preferences regarding future medical care. The major psychological impact of transforming oncology care to teleconferences and videoconferences and of the important strict recommendation of social distancing must not be overlooked in a patient population that is characterised by significant prevalence of cognitive decline and by the general perception that their life span may not exceed the life span of the COVID-19 pandemic

The influence of patient sex on clinical approaches to malignant glioma

Gliomas are tumors that originate from the glial tissue, thus involving the central nervous system with varying degrees of malignancy. The most aggressive and frequent form is glioblastoma multiforme, a disease characterized by resistance to therapies, frequent recurrences, and extremely poor median survival time. Data on overall glioma case studies demonstrate clear sex disparities regarding incidence, prognosis, drug toxicity, clinical outcome, and, recently, prediction of therapeutic response. In this study, we analyze data in the literature regarding malignant glioma, mainly glioblastoma multiforme, focusing on epidemiological and clinical evaluations. Less discussed issues, such as the role of viral infections, energy metabolism, and predictive aspects concerning the possible use of dedicated therapeutic approaches for male or female patients, will be reported together with different estimated pathogenetic mechanisms underlying astrocyte transformation and glioma chemosensitivity. In this era, where personalized/precision medicine is the most important driver for targeted cancer therapies, the lines of evidence discussed herein strongly suggest that clinical approaches to malignant glioma should consider the patient's sex. Furthermore, retrospectively revising previous clinical studies considering patient sex as a crucial variable is recommended.

Zika virus infection induces MiR34c expression in glioblastoma stem cells: new perspectives for brain tumor treatments

Zika virus (ZIKV) is a flavivirus with a marked effect on fetal nervous system development. ZIKV treatment has recently been found to also have a benefit against glioblastoma, a highly aggressive brain tumor with a poor prognosis. The reported data do not completely explain the mechanism beyond this effect. Nevertheless, in the majority of the cases no adverse effect has been found in healthy adult humans. In this study, we characterized the ZIKV infection mechanism on glioblastoma stem cells, which are considered responsible for the tumor progression and resistance to conventional therapies. Moreover, we explain why the action of this virus is directed to the stem cells in the nervous system counterpart. Our results confirm the effectiveness of ZIKV treatment against glioblastoma, indicating novel molecular targets that can be introduced for more powerful therapies.

The Inhibition of miR-144-3p on Cell Proliferation and Metastasis by Targeting TOP2A in HCMV-Positive Glioblastoma Cells

Glioblastoma (GBM), the most common type of primary tumor in the central nervous system, is a very aggressive brain tumor with poor prognosis and a high recurrence rate. Increasing evidence suggests that human cytomegalovirus (HCMV) infection is related to GBM and leads to GBM cell growth and metastasis. MicroRNAs are important regulators in the growth and metastasis of glioblastoma. This study aimed to demonstrate the role of miR-144-3p in HCMV-positive glioblastoma. We found that, after HCMV infection, the expression of miR-144-3p decreased, whereas the expression of TOP2A increased. Bioinformatics analyses indicated that miR-144-3p directly targets the TOP2A 3'-UTR (Untranslated Region). We discovered that the overexpression of miR-144-3p downregulated the overexpression of TOP2A and inhibited the proliferation, clone formation, and invasion of HCMV-positive glioma in vitro. Taken together, these results show that miR-144-3p inhibited growth and promoted apoptosis in glioma cells by targeting TOP2A.

CMV and EBV targets recognized by tumor-infiltrating B lymphocytes in pancreatic cancer and brain tumors

Targeted antiviral immune responses to the widespread human pathogens cytomegalovirus (CMV) and Epstein-Barr virus (EBV) play a pivotal role in determining immune fitness. We show here for the first time that tumor-infiltrating B cell (TIB)- derived immunoglobulin G (IgG) from patients with pancreatic cancer or glioblastoma have unique anti-CMV/EBV immune recognition patterns compared to serum IgG. There is also great heterogeneity between patients, as well as between serum and TIB-IgG, while some viral targets elicited strongly both T-cell and IgG reactivity in tumor infiltrating T- and B-cells. These observations suggest that the anti-CMV/EBV humoral immune response in situ is highly unique and can be instrumental in developing next-generation immuno-biomarkers in addition to supplementing cellular therapy strategies for personalized cancer therapy targeting CMV or EBV in the tumor microenvironment.

Oncolytic Virotherapy for the Treatment of Malignant Glioma

Malignant glioma is the most common primary brain tumor and carries a grim prognosis, with a median survival of just over 14 months. Given the poor outcomes with standard-of-care treatments, novel treatment strategies are needed. The concept of virotherapy for the treatment of malignant tumors dates back more than a century and can be divided into replication-competent oncolytic viruses and replication-deficient viral vectors. Oncolytic viruses are designed to selectively target, infect, and replicate in tumor cells, while sparing surrounding normal brain. A host of oncolytic viruses has been evaluated in early phase human trials with promising safety results, but none has progressed to phase III trials. Despite the 25 years that has passed since the initial publication of genetically engineered oncolytic viruses for the treatment of glioma, much remains to be learned about the use of this therapy, including its mechanism of action, optimal treatment paradigm, appropriate targets, and integration with adjuvant agents. Oncolytic viral therapy for glioma remains promising and will undoubtedly impact the future of patient care.

Development of Extranodal NK/T-cell Lymphoma Nasal Type in Cerebrum Following Epstein-Barr Virus-positive Uveitis

A 74-year-old woman developed bilateral uveitis with high Epstein-Barr virus (EBV) DNA load in the vitreous fluid without lymphoma cells. Four years after the onset, T2-weighted contrast-enhanced MRI revealed hyperintense lesions in the right occipital and parietal lobe. A biopsy resulted in the diagnosis of extranodal NK/T-cell lymphoma nasal type (ENKL). The repeat region of LMP1, an EBV gene, detected in the brain lesion was identical to that detected in the vitreous fluid. ENKL of the central nervous system is quite rare, and the pathogenesis has not been determined. The lymphoma in this case might have been closely associated with the EBV-positive uveitis.

JC polyomavirus in the aetiology and pathophysiology of glial tumours

Glial brain tumours with their poor prognosis, limited treatment modalities and unclear detailed pathophysiology represent a significant health concern. The purpose of the current study was to investigate and describe the possible role of the human polyomavirus JC as an underlying cancerogenic or co-cancerogenic factor in the complex processes of glial tumour induction and development. Samples from 101 patients with glial tumours were obtained during neurosurgical tumour resection. Small tissue pieces were taken from several areas of the histologically verified solid tumour core. Biopsies were used for DNA extraction and subsequent amplification reactions of sequences from the JC viral genome. Real-time polymerase chain reaction was used for detection and quantification of its non-coding control region (NCCR) and gene encoding the regulatory protein Large T antigen (LT). An average of 37.6% of all patients was found to be LT positive, whereas only 6.9% tested positive for NCCR. The analysis of the results demonstrated significant variance between the determined LT prevalence and the rate for NCCR, with a low starting copy number in all positive samples and threshold cycles in the range of 36 to 42 representing viral load in the range from 10 to 1000 copies/μl. The results most probably indicate incomplete JC viral replication. Under such conditions, mutations in the host cell genome may be accumulated due to interference of the virus with the host cell machinery, and eventually malignant transformation may occur.

Histone deacetylase 6 inhibition enhances oncolytic viral replication in glioma

Oncolytic viral (OV) therapy, which uses genetically engineered tumor-targeting viruses, is being increasingly used in cancer clinical trials due to the direct cytolytic effects of this treatment that appear to provoke a robust immune response against the tumor. As OVs enter tumor cells, intrinsic host defenses have the potential to hinder viral replication and spread within the tumor mass. In this report, we show that histone deacetylase 6 (HDAC6) in tumor cells appears to alter the trafficking of post-entry OVs from the nucleus toward lysosomes. In glioma cell lines and glioma-stem-like cells, HDAC6 inhibition (HDAC6i) by either pharmacologic or genetic means substantially increased replication of oncolytic herpes simplex virus type 1 (oHSV). Moreover, HDAC6i increased shuttling of post-entry oHSV to the nucleus. In addition, electron microscopic analysis revealed that post-entry oHSVs are preferentially taken up into glioma cells through the endosomal pathway rather than via fusion at the cell surface. Together, these findings illustrate a mechanism of glioma cell defense against an incoming infection by oHSV and identify possible approaches to enhance oHSV replication and subsequent lysis of tumor cells.

Analysis of Glioblastoma Patients' Plasma Revealed the Presence of MicroRNAs with a Prognostic Impact on Survival and Those of Viral Origin

Background

Glioblastoma multiforme (GBM) is among the most aggressive cancers with a poor prognosis in spite of a plethora of established diagnostic and prognostic biomarkers and treatment modalities. Therefore, the current goal is the detection of novel biomarkers, possibly detectable in the blood of GBM patients that may enable an early diagnosis and are potential therapeutic targets, leading to more efficient interventions.

Experimental Procedures

MicroRNA profiling of 734 human and human-associated viral miRNAs was performed on blood plasma samples from 16 healthy individuals and 16 patients with GBM, using the nCounter miRNA Expression Assay Kits.

Results

We identified 19 miRNAs with significantly different plasma levels in GBM patients, compared to the healthy individuals group with the difference limited by a factor of 2. Additionally, 11 viral miRNAs were found differentially expressed in plasma of GBM patients and 24 miRNA levels significantly correlated with the patients’ survival. Moreover, the overlap between the group of candidate miRNAs for diagnostic biomarkers and the group of miRNAs associated with survival, consisted of ten miRNAs, showing both diagnostic and prognostic potential. Among them, hsa miR 592 and hsa miR 514a 3p have not been previously described in GBM and represent novel candidates for selective biomarkers. The possible signalling, induced by the revealed miRNAs is discussed, including those of viral origin, and in particular those related to the impaired immune response in the progression of GBM.

Conclusion

The GBM burden is reflected in the alteration of the plasma miRNAs pattern, including viral miRNAs, representing the potential for future clinical application. Therefore proposed biomarker candidate miRNAs should be validated in a larger study of an independent cohort of patients.

PKCη/Rdx-driven phosphorylation of PDK1: a novel mechanism promoting cancer cell survival and permissiveness for parvovirus-induced lysis

The intrinsic oncotropism and oncosuppressive activities of rodent protoparvoviruses (PVs) are opening new prospects for cancer virotherapy. Virus propagation, cytolytic activity, and spread are tightly connected to activation of the PDK1 signaling cascade, which delays stress-induced cell death and sustains functioning of the parvoviral protein NS1 through PKC(η)-driven modifications. Here we reveal a new PV-induced intracellular loop-back mechanism whereby PKCη/Rdx phosphorylates mouse PDK1:S138 and activates it independently of PI3-kinase signaling. The corresponding human PDK1phosphoS135 appears as a hallmark of highly aggressive brain tumors and may contribute to the very effective targeting of human gliomas by H-1PV. Strikingly, although H-1PV does not trigger PDK1 activation in normal human cells, such cells show enhanced viral DNA amplification and NS1-induced death upon expression of a constitutively active PDK1 mimicking PDK1phosphoS135. This modification thus appears as a marker of human glioma malignant progression and sensitivity to H-1PV-induced tumor cell killing.

The H-1 protoparvovirus (H-1PV) is the first replication-competent member of the Parvoviridae family to undergo a phase I/IIa clinical trial in patients suffering from glioblastoma multiforme. Although the intrinsic oncotropism and oncolytic activity of protoparvoviruses are well known, the underlying molecular mechanisms remain elusive. Here we identify a PV-induced intracellular loop-back mechanism that promotes PV replication and cytotoxicity through PI3-kinase-independent stimulation of PDK1 and of the PKC and PKB/Akt1 downstream kinases. This mechanism involves PKCη/Rdx-mediated phosphorylation of PDK1 (at S138 in mouse or S135 in human). Interestingly, this phosphorylation appears as a hallmark of highly aggressive brain tumors. Although H-1PV does not promote it in normal human cells, experimentally administered activated PDK1 variants were able to sensitize these cells to virus infection. These data lead us to propose PDK1phosphoS135 as a new candidate marker for monitoring tumor progression and responsiveness to oncolytic parvovirotherapy, particularly in the case of highly aggressive brain tumors. Furthermore, the sensitivity of PDK1phosphoS135-positive cell lines to inhibitors of PKCη/Rdx argues for considering this complex as a potential target for anticancer drug development.

Frequency of Epstein-Barr virus DNA sequences in human gliomas

CONTEXT AND OBJECTIVE

The Epstein-Barr virus (EBV) is the most common cause of infectious mononucleosis and is also associated with several human tumors, including Burkitt's lymphoma, Hodgkin's lymphoma, some cases of gastric carcinoma and nasopharyngeal carcinoma, among other neoplasms. The aim of this study was to screen 75 primary gliomas for the presence of specific EBV DNA sequences by means of the polymerase chain reaction (PCR), with confirmation by direct sequencing.

DESIGN AND SETTING

Prevalence study on EBV molecular genetics at a molecular pathology laboratory in a university hospital and at an applied genetics laboratory in a national institution.

METHODS

A total of 75 primary glioma biopsies and 6 others from other tumors from the central nervous system were obtained. The tissues were immediately frozen for subsequent DNA extraction by means of traditional methods using proteinase K digestion and extraction with a phenol-chloroform-isoamyl alcohol mixture. DNA was precipitated with ethanol, resuspended in buffer and stored. The PCRs were carried out using primers for amplification of the EBV BamM region. Positive and negative controls were added to each reaction. The PCR products were used for direct sequencing for confirmation.

RESULTS

The viral sequences were positive in 11/75 (14.7%) of our samples.

CONCLUSION

The prevalence of EBV DNA was 11/75 (14.7%) in our glioma collection. Further molecular and epidemiological studies are needed to establish the possible role played by EBV in the tumorigenesis of gliomas.

Human cytomegalovirus gene expression in long-term infected glioma stem cells

The most common adult primary brain tumor, glioblastoma (GBM), is characterized by fifteen months median patient survival and has no clear etiology. We and others have identified the presence of human cytomegalovirus (HCMV) gene products endogenously expressed in GBM tissue and primary cells, with a subset of viral genes being consistently expressed in most samples. Among these viral genes, several have important oncomodulatory properties, regulating tumor stemness, proliferation, immune evasion, invasion and angiogenesis. These findings lead us to hypothesize that a specific HCMV gene signature may be associated with GBM pathogenesis. To investigate this hypothesis, we used glioma cell lines and primary glioma stem-like cells (GSC) infected with clinical and laboratory HCMV strains and measured relative viral gene expression levels along several time points up to 15 weeks post-infection. While HCMV gene expression was detected in several infected glioma lines through week 5 post-infection, only HCMV-infected GSC expressed viral gene products 15 weeks post-infection. Efficiency of infection across time was higher in GSC compared to cell lines. Importantly, HCMV-infected GSC outlived their uninfected counterparts, and this extended survival was paralleled by increased tumorsphere frequency and upregulation of stemness regulators, such as SOX2, p-STAT3, and BMX (a novel HCMV target identified in this study). Interleukin 6 (IL-6) treatment significantly upregulated HCMV gene expression in long-term infected glioma cultures, suggesting that pro-inflammatory signaling in the tumor milieu may further augment HCMV gene expression and subsequent tumor progression driven by viral-induced cellular signaling. Together, our data support a critical role for long-term, low-level HCMV infection in promoting survival, stemness, and proliferation of GSC that could significantly contribute to GBM pathogenesis.

Enterovirus 71 induces mitochondrial reactive oxygen species generation that is required for efficient replication

Redox homeostasis is an important host factor determining the outcome of infectious disease. Enterovirus 71 (EV71) infection has become an important endemic disease in Southeast Asia and China. We have previously shown that oxidative stress promotes viral replication, and progeny virus induces oxidative stress in host cells. The detailed mechanism for reactive oxygen species (ROS) generation in infected cells remains elusive. In the current study, we demonstrate that mitochondria were a major ROS source in EV71-infected cells. Mitochondria in productively infected cells underwent morphologic changes and exhibited functional anomalies, such as a decrease in mitochondrial electrochemical potential ΔΨ_m and an increase in oligomycin-insensitive oxygen consumption. Respiratory control ratio of mitochondria from infected cells was significantly lower than that of normal cells. The total adenine nucleotide pool and ATP content of EV71-infected cells significantly diminished. However, there appeared to be a compensatory increase in mitochondrial mass. Treatment with mito-TEMPO reduced eIF2α phosphorylation and viral replication, suggesting that mitochondrial ROS act to promote viral replication. It is plausible that EV71 infection induces mitochondrial ROS generation, which is essential to viral replication, at the sacrifice of efficient energy production, and that infected cells up-regulate biogenesis of mitochondria to compensate for their functional defect.

[Methotrexate-related lymphomatoid granulomatosis successfully treated with discontinuation of methotrexate and radiotherapy to brain]

A 70-year-old woman with rheumatoid arthritis treated with methotrexate (MTX) complained of right arm weakness. On CT and MRI, tumors were found in the right frontal lobe, bilateral lungs, and left renal parenchyma. She was diagnosed as having lymphomatoid granulomatosis (LYG) grade 2 on thoracoscopic biopsy of the left lung. We discontinued MTX and treated a mass lesion in the right frontal lobe with stereotactic radiotherapy. As a result, the tumors showed a gradual reduction in size, and the patient achieved complete remission. LYG is a rare lymphoproliferative disorder, and has various clinical characteristics. We describe herein a patient with LYG grade 2 with cerebral, pulmonary, and renal lesions, who has maintained a complete remission for six months, to date, after treatment.

Glioma virus therapies between bench and bedside

Despite extensive research, current glioma therapies are still unsatisfactory, and novel approaches are pressingly needed. In recent years, both nonreplicative viral vectors and replicating oncolytic viruses have been developed for brain cancer treatment, and the mechanistic background of their cytotoxicity has been unveiled. A growing number of clinical trials have convincingly established viral therapies to be safe in glioma patients, and maximum tolerated doses have generally not been reached. However, evidence for therapeutic benefit has been limited: new generations of therapeutic vectors need to be developed in order to target not only tumor cells but also the complex surrounding microenvironment. Such therapies could also direct long-lasting immune responses toward the tumor while reducing early antiviral reactions. Furthermore, viral delivery methods are to be improved and viral spread within the tumor will have to be enhanced. Here, we will review the outcome of completed glioma virus therapy trials as well as highlight the ongoing clinical activities. On this basis, we will give an overview of the numerous strategies to enhance therapeutic efficacy of new-generation viruses and novel treatment regimens. Finally, we will conclude with approaches that may be crucial to the development of successful glioma therapies in the future.

Evidence of association of human papillomavirus with prognosis worsening in glioblastoma multiforme

BACKGROUND

Glioblastoma multiforme (GBM) is the most malignant brain tumor in adults, but its etiology still remains unknown. Recently, a role of viruses such as cytomegalovirus and JC virus in gliomagenesis has been suggested. Since human papillomavirus (HPV) is considered the most common oncogenic virus in humans, we evaluated its occurrence in GBM samples.

MATERIAL AND METHODS

Fifty-two formalin-fixed paraffin-embedded primary glioblastoma specimens were retrospectively analyzed. The presence of HPV genome on tumor DNA was assessed by MY/GP nested PCR. Confirmation of HPV detection was obtained by chromogenic in situ hybridization (CISH) and immunohistochemistry (IHC) with an antibody directed against the L1 capsidic protein. Finally, univariate and multivariate proportional-hazards models were used to compare the risk of death among HPV-positive and HPV-negative patients.

RESULTS

Strikingly, viral DNA was detected after PCR in 12 cases (23%). HPV16 genome was present in 25% infected samples, whereas the remaining samples tested positive for HPV6. CISH confirmed positivity in all infected samples for which enough material was available. Moreover, IHC positivity suggested that production of viral proteins from HPV genome is an ongoing process in GBM cancer cells. Finally an association between HPV infection and a worse prognosis was found in patients upon age stratification with a univariate analysis (HR, 2.10; 95% CI, 1.00-4.44; log-rank P = .045).

CONCLUSIONS

HPV infection status may be considered an independent prognostic factor in GBM patients and suggests that prevention may be considered, should HPV be recognized as a causative agent in gliomagenesis.

Preclinical evaluation of engineered oncolytic herpes simplex virus for the treatment of neuroblastoma

Despite intensive research efforts and therapeutic advances over the last few decades, the pediatric neural crest tumor, neuroblastoma, continues to be responsible for over 15% of pediatric cancer deaths. Novel therapeutic options are needed for this tumor. Recently, investigators have shown that mice with syngeneic murine gliomas treated with an engineered, neuroattenuated oncolytic herpes simplex virus-1 (oHSV), M002, had a significant increase in survival. M002 has deletions in both copies of the γ₁34.5 gene, enabling replication in tumor cells but precluding infection of normal neural cells. We hypothesized that M002 would also be effective in the neural crest tumor, neuroblastoma. We showed that M002 infected, replicated, and decreased survival in neuroblastoma cell lines. In addition, we showed that in murine xenografts, treatment with M002 significantly decreased tumor growth, and that this effect was augmented with the addition of ionizing radiation. Importantly, survival could be increased by subsequent doses of radiation without re-dosing of the virus. Finally, these studies showed that the primary entry protein for oHSV, CD111 was expressed by numerous neuroblastoma cell lines and was also present in human neuroblastoma specimens. We concluded that M002 effectively targeted neuroblastoma and that this oHSV may have potential for use in children with unresponsive or relapsed neuroblastoma.

Case of the month: March 1999--A 26 year old HIV positive male with dura based masses

A 26-year-old male with AIDS presented with a chief complaint of headaches and neck pain. An MRI revealed two enhancing extra-axial dura based masses, one in the area of the left sphenoid wing and one at the level of C2-3. In both cases, microscopic sections showed actin positive spindle cell neoplasms with long slender nuclei, consistent with leiomyomas. Both tumors were positive for Epstein Barr virus by in situ hybridization. This case report serves to emphasize the importance of considering soft tissue tumors such as leiomyoma in the differential diagnosis of mass lesions that occur in the central nervous system in AIDS and discusses the role of EBV in tumorigenesis.

Coronaviruses lacking exoribonuclease activity are susceptible to lethal mutagenesis: evidence for proofreading and potential therapeutics

No therapeutics or vaccines currently exist for human coronaviruses (HCoVs). The Severe Acute Respiratory Syndrome-associated coronavirus (SARS-CoV) epidemic in 2002–2003, and the recent emergence of Middle East Respiratory Syndrome coronavirus (MERS-CoV) in April 2012, emphasize the high probability of future zoonotic HCoV emergence causing severe and lethal human disease. Additionally, the resistance of SARS-CoV to ribavirin (RBV) demonstrates the need to define new targets for inhibition of CoV replication. CoVs express a 3′-to-5′ exoribonuclease in nonstructural protein 14 (nsp14-ExoN) that is required for high-fidelity replication and is conserved across the CoV family. All genetic and biochemical data support the hypothesis that nsp14-ExoN has an RNA proofreading function. Thus, we hypothesized that ExoN is responsible for CoV resistance to RNA mutagens. We demonstrate that while wild-type (ExoN+) CoVs were resistant to RBV and 5-fluorouracil (5-FU), CoVs lacking ExoN activity (ExoN−) were up to 300-fold more sensitive. While the primary antiviral activity of RBV against CoVs was not mutagenesis, ExoN− CoVs treated with 5-FU demonstrated both enhanced sensitivity during multi-cycle replication, as well as decreased specific infectivity, consistent with 5-FU functioning as a mutagen. Comparison of full-genome next-generation sequencing of 5-FU treated SARS-CoV populations revealed a 16-fold increase in the number of mutations within the ExoN− population as compared to ExoN+. Ninety percent of these mutations represented A:G and U:C transitions, consistent with 5-FU incorporation during RNA synthesis. Together our results constitute direct evidence that CoV ExoN activity provides a critical proofreading function during virus replication. Furthermore, these studies identify ExoN as the first viral protein distinct from the RdRp that determines the sensitivity of RNA viruses to mutagens. Finally, our results show the importance of ExoN as a target for inhibition, and suggest that small-molecule inhibitors of ExoN activity could be potential pan-CoV therapeutics in combination with RBV or RNA mutagens.

RNA viruses have high mutation rates (10⁻³ to 10⁻⁵ mutations/nucleotide/round of replication), allowing for rapid viral adaptation in response to selective pressure. While RNA viruses have long been considered unable to correct mistakes during replication, CoVs such as SARS-CoV and the recently emerged MERS-CoV are important exceptions to this paradigm. All CoVs encode an exoribonuclease activity in nonstructural protein 14 (nsp14-ExoN) that is proposed to prevent and/or remove misincorporated nucleotides. Because of the demonstrated resistance of SARS-CoV to the antiviral drug ribavirin (RBV), we hypothesized that ExoN is responsible for CoV resistance to RNA mutagens. Using RBV and the RNA mutagen 5-fluorouracil (5-FU), we show that CoVs lacking ExoN activity (ExoN−) are highly susceptible to RBV and 5-FU, in contrast to wild-type (ExoN+) CoVs. The inhibitory activity of 5-FU against ExoN− viruses resulted specifically from 5-FU incorporation during viral RNA synthesis that lead to extensive mutagenesis within the viral population, and was associated with a profound decrease in virus specific infectivity. These results demonstrate the proofreading activity of ExoN during virus replication and suggest that inhibitors of ExoN activity could be broadly useful inhibitors of CoV replication in combination with RBV or RNA mutagens.

STAT3 activation promotes oncolytic HSV1 replication in glioma cells

Recent studies report that STAT3 signaling is a master regulator of mesenchymal transformation of gliomas and that STAT3 modulated genes are highly expressed in the mesenchymal transcriptome of gliomas. A currently studied experimental treatment for gliomas consists of intratumoral injection of oncolytic viruses (OV), such as oncolytic herpes simplex virus type 1 (oHSV). We have described one particular oHSV (rQNestin34.5) that exhibits potent anti-glioma activity in animal models. Here, we hypothesized that alterations in STAT3 signaling in glioma cells may affect the replicative ability of rQNestin34.5. In fact, human U251 glioma cells engineered to either over-express STAT3 or with genetic down-regulation of STAT3 supported oHSV replication to a significantly higher or lesser degree, respectively, when compared to controls. Administration of pharmacologic agents that increase STAT3 phosphorylation/activation (Valproic Acid) or increase STAT3 levels (Interleukin 6) also significantly enhanced oHSV replication. Instead, administration of inhibitors of STAT3 phosphorylation/activation (LLL12) significantly reduced oHSV replication. STAT3 led to a reduction in interferon signaling in oHSV infected cells and inhibition of interferon signaling abolished the effect of STAT3 on oHSV replication. These data thus indicate that STAT3 signaling in malignant gliomas enhances oHSV replication, likely by inhibiting the interferon response in infected glioma cells, thus suggesting avenues for possible potentiation of oncolytic virotherapy.

Epstein-Barr Virus associated primary intracranial smooth muscle tumor in HIV positive patient: case report and review of the literature

The authors report a case of HIV-positive patient with primary intracranial smooth muscle tumor Evidence of Epstein-Barr Virus (EB V) infection in this tumor is proven by in situ hybridization for EBV-encoded RNA (EBER). Review of the literature shows that the occurring of smooth muscle tumor at intracranial site is extremely rare and most cases are HIV-infected patient. It also shows an association with EBV infection.

Myxoma virus infection promotes NK lysis of malignant gliomas in vitro and in vivo

Myxoma virus (MYXV) is a well-established oncolytic agent against different types of tumors. MYXV is also known for its immunomodulatory properties in down-regulating major histocompatibility complex (MHC) I surface expression (via the M153R gene product, a viral E3-ubiquitin ligase) and suppressing T cell killing of infected target cells. MHC I down-regulation, however, favors NK cell activation. Brain tumors including gliomas are characterized by high MHC I expression with impaired NK activity. We thus hypothesized that MYXV infection of glioma cells will promote NK cell-mediated recognition and killing of gliomas. We infected human gliomas with MYXV and evaluated their susceptibility to NK cell-mediated cytotoxicity. MYXV enhanced NK cell-mediated killing of glioma cells (U87 cells, MYXV vs. Mock: 51.73% vs. 28.63%, P = .0001, t test; U251 cells, MYXV vs. Mock: 40.4% vs. 20.03%, P .0007, t test). Using MYXV M153R targeted knockout (designated vMyx-M153KO) to infect gliomas, we demonstrate that M153R was responsible for reduced expression of MHC I on gliomas and enhanced NK cell-mediated antiglioma activity (U87 cells, MYXV vs. vMyx-M153KO: 51.73% vs. 25.17%, P = .0002, t test; U251 cells, MYXV vs. vMyx-M153KO: 40.4% vs. 19.27, P = .0013, t test). Consequently, NK cell-mediated lysis of established human glioma tumors in CB-17 SCID mice was accelerated with improved mouse survival (log-rank P = .0072). These results demonstrate the potential for combining MYXV with NK cells to effectively kill malignant gliomas.

Epstein-Barr viral load in cerebrospinal fluid as a diagnostic marker of central nervous system involvement of AIDS-related lymphoma

OBJECTIVE

AIDS-related lymphoma (ARL) often involves the central nervous system (CNS). Although the diagnostic value of Epstein-Barr virus (EBV)-DNA in cerebrospinal fluid (CSF) in detecting HIV-positive primary CNS lymphoma (PCNSL) has been established, its usefulness for identifying CNS involvement of systemic ARL remains elusive. In this study, we evaluated the utility of the EBV-DNA load in CSF in identifying CNS involvement in patients with systemic ARL.

METHODS

We retrospectively reviewed the clinical and pathological data of consecutive ARL patients managed at our clinic between January 1998 and June 2012. Sixty-two patients with ARL, including eight PCNSL patients and 52 systemic ARL patients, and 63 controls underwent CSF EBV-DNA load evaluations before receiving chemotherapy. ARL-related CNS involvement was defined as any lesion diagnosed histologically or radiologically as a lymphoma in the brain, meninges, spine, cranial nerves or oculus.

RESULTS

A cut off value of 200 copies/mL predicted the presence of CNS lesions with a sensitivity of 70% and a specificity of 85% in both the PCNSL and systemic ARL patients, while a sensitivity of 75% and a specificity of 93% were obtained for systemic ARL. A cut off value of 2,000 (3.30 log) copies/mL provided the best specificity (100%), with a sensitivity of 50%.

CONCLUSION

Our results support the clinical utility of evaluating the quantitative EBV-DNA load in the CSF for the diagnosis of CNS involvement of systemic ARL as well as PCNSL.

[Oncolytic viruses in the therapy of gliomas]

Despite the advances of modern medicine, malignant glioblastoma cure remains an elusive goal. Both the invasive nature and location in vital areas of the brain make this type of tumors difficult for surgical treatment, while the current adjuvant therapy is not as successful as expected. Frequent recurrence and invasiveness of malignant gliomas is due to resistance of glioma stem cells to conventional radiation and chemotherapy. Technological advances in constructing recombinant viruses have allowed creating strains with high oncolytic activity toward glial tumors. Many of these strains have passed Phase I of clinical trials and demonstrated high safety. Despite the obvious potential of the approach, efficiency of the existing strains is still far from being sufficient for effectively curing the disease and require further improvement. The review summarizes results obtained with the most successful variants of oncolytic viruses that come down to the clinical trials and discusses the prospects for new approaches in virotherapy of malignant gliomas.

JC virus T-antigen regulates glucose metabolic pathways in brain tumor cells

Recent studies have reported the detection of the human neurotropic virus, JCV, in a significant population of brain tumors, including medulloblastomas. Accordingly, expression of the JCV early protein, T-antigen, which has transforming activity in cell culture and in transgenic mice, results in the development of a broad range of tumors of neural crest and glial origin. Evidently, the association of T-antigen with a range of tumor-suppressor proteins, including p53 and pRb, and signaling molecules, such as β-catenin and IRS-1, plays a role in the oncogenic function of JCV T-antigen. We demonstrate that T-antigen expression is suppressed by glucose deprivation in medulloblastoma cells and in glioblastoma xenografts that both endogenously express T-antigen. Mechanistic studies indicate that glucose deprivation-mediated suppression of T-antigen is partly influenced by 5′-activated AMP kinase (AMPK), an important sensor of the AMP/ATP ratio in cells. In addition, glucose deprivation-induced cell cycle arrest in the G1 phase is blocked with AMPK inhibition, which also prevents T-antigen downregulation. Furthermore, T-antigen prevents G1 arrest and sustains cells in the G2 phase during glucose deprivation. On a functional level, T-antigen downregulation is partially dependent on reactive oxygen species (ROS) production during glucose deprivation, and T-antigen prevents ROS induction, loss of ATP production, and cytotoxicity induced by glucose deprivation. Additionally, we have found that T-antigen is downregulated by the glycolytic inhibitor, 2-deoxy-D-glucose (2-DG), and the pentose phosphate inhibitors, 6-aminonicotinamide and oxythiamine, and that T-antigen modulates expression of the glycolytic enzyme, hexokinase 2 (HK2), and the pentose phosphate enzyme, transaldolase-1 (TALDO1), indicating a potential link between T-antigen and metabolic regulation. These studies point to the possible involvement of JCV T-antigen in medulloblastoma proliferation and the metabolic phenotype and may enhance our understanding of the role of viral proteins in glycolytic tumor metabolism, thus providing useful targets for the treatment of virus-induced tumors.

Varicella zoster virus infection of malignant glioma cell cultures: a new candidate for oncolytic virotherapy?

BACKGROUND

Glioblastoma multiforme is a highly aggressive tumor with a median survival of 14 months despite all standard therapies. Focusing on alternative treatment strategies, we evaluated the oncolytic potential of varicella zoster virus (VZV) in malignant glioma cell cultures.

MATERIALS AND METHODS

Replication of wildtype and mutant VZV was comparatively analyzed in glioma cell lines (U87, U251 and U373) and in primary malignant glioma cells (n=10) in vitro by infectious foci assay, immunofluorescence microscopy and western blot analysis. Additionally, the tumor-targeting potential of VZV-infected human mesenchymal stem cells was evaluated.

RESULTS

VZV replicated efficiently in all the glioma cells studied here followed by rapid oncolysis in vitro. The attenuated vaccine VZV mutant rOKA/ORF63rev[T171] exhibited most efficient replication. Human mesenchymal stem cells were found suitable for targeting VZV to sites of tumor growth.

CONCLUSION

VZV exhibits an intrinsic oncolytic potential in malignant glioma cell cultures and might be a novel candidate for virotherapy in glioblastoma multiforme.

Oncolytic herpes simplex virus counteracts the hypoxia-induced modulation of glioblastoma stem-like cells

Glioblastoma (GBM), a fatal malignant brain tumor, contains abundant hypoxic regions that provide a "niche" to promote both the maintenance and enrichment of glioblastoma stem-like cells (GSCs) and confer resistance to chemo- and radiotherapy. Since GSCs, with an ability to resist conventional therapies, may be responsible for tumor recurrence, targeting GSCs located in such a hypoxic environment may be critical to improving the therapeutic outcome for GBM patients. Oncolytic viral therapies have been tested in the clinic as a promising therapeutic approach for GBM. In this study, we analyzed and compared the therapeutic effects of oncolytic herpes simplex virus (oHSV) type 1 G47Δ (γ34.5(-)ICP6(-)LacZ(+)α47(-)) in patient-derived GSCs under normoxia (21% oxygen) and hypoxia (1% oxygen). GSCs cultured in hypoxia showed an increased ability to form neurospheres and expressed higher levels of the putative stem cell marker CD133 compared with GSCs cultured in normoxia. G47Δ exhibited a comparable ability to infect, replicate, and kill GSCs in normoxia and hypoxia in vitro. Importantly, G47Δ could counteract hypoxia-mediated enhancement of the stem-like properties of GSCs, inhibiting their self-renewal and stem cell marker expression. Using orthotopic human GSC xenografts in mice, we demonstrated that intratumoral injection of G47ΔUs11fluc, a newly developed G47Δ derivative that expresses firefly luciferase driven by a true late viral promoter, led to an equivalent frequency of viral infection and replication in hypoxic and nonhypoxic tumor areas. These findings suggest that oHSV G47Δ represents a promising therapeutic strategy to target and kill GSCs, not only in normoxic areas of GBM but also within the hypoxic niche.

Detection of Epstein-Barr virus DNA and expression of CD30 antigen in primary anaplastic diffuse large B-cell lymphoma of the brain

We describe a case of primary anaplastic diffuse large-cell lymphoma arising in the central nervous system (CNS). Primary CD30-positive anaplastic diffuse large B-cell lymphoma of the brain is very rarely reported. Given that this tumor is immunohistochemically heterogeneous, polymerase chain reaction (PCR) and Epstein-Barr virus (EBV) analysis of tumor DNA are essential techniques for early and accurate histological diagnosis in these CD30-positive cerebral lymphoma cases. We report an early CD30- and EBV-positive anaplastic diffuse large B-cell lymphoma in the CNS that was diagnosed not only from the immunohistochemical study and MRI findings, but also from the genotype confirmations. This tumor was documented to have EBV episomes of monoclonal origin by PCR analysis of immunoglobulin gene rearrangement.

No consistent relationship of glioblastoma incidence and cytomegalovirus seropositivity in whites, blacks, and Hispanics

Glioblastoma multiforme is the most common and most aggressive type of primary brain tumor, accounting for 52% of all primary brain tumor cases and 20% of all intracranial tumors. Recently, evidence for a viral cause has been postulated, possibly cytomegalovirus (CMV). In one report, 80% of patients with newly diagnosed glioblastoma multiforme had detectable cytomegalovirus DNA in their peripheral blood, while sero-positive normal donors and other surgical patients did not exhibit detectable virus. However, another study reported that five glioblastoma patients showed no circulating CMV detected either with RT-PCR or blood culture.

MATERIALS AND METHODS

We utilized Cytomegalovirus Seroprevalence in the United States data from the National Health and Nutrition Examination Surveys, 1988-2004. Glioblastoma Incidence Rates 2004-2008 by race and gender are from Cancer of the Brain and Other Nervous System - SEER Stat Fact Sheets (http://seer.cancer.gov/statfacts/html/brain.html). Statistical significance was determined from published 95% confidence intervals.

RESULTS

CMV seroprevalence rates are not consistently related to glioblastoma incidence rates. CMV seroprevalence is significantly lower in whites than in blacks or Hispanics (Mexican Americans), while glioblastoma incidence is higher. However, both CMV seroprevalence and glioblastoma incidence are higher in Hispanics than in blacks. CMV seroprevalence rates are significantly higher in women, 55.5% (53.3-57.7, mean ± 95% CI) than men, 45.2% (42.4-48.0), although glioblastoma is more common in men.

CONCLUSION

A possible CMV-glioblastoma association cannot be readily substantiated with CMV seropositivity rates.

Myxoma virus virotherapy for glioma in immunocompetent animal models: optimizing administration routes and synergy with rapamycin

Oncolytic myxoma virus (MYXV) is being developed as a novel virotherapeutic against human brain cancer and has promising activity against human brain tumor models in immunocompromised hosts. Because an intact immune system could reduce its efficacy, the purpose of this study was to evaluate the oncolytic potential of MYXV in immunocompetent racine glioma models. Here, we report that MYXV infects and kills all racine cell glioma lines and that its effects are enhanced by rapamycin. Intratumoral administration of MYXV with rapamycin improved viral replication in the tumor and significantly prolonged host survival. Similarly, coadministration via a method of convection-enhanced delivery (CED) enhanced viral replication and efficacy in vivo. Mechanisms by which rapamycin improved MYXV oncolysis included an inhibition of type I IFN production in vitro and a reduction of intratumoral infiltration of CD68(+) microglia/macrophages and CD163(+) macrophages in vivo. Our findings define a method to improve MYXV efficacy against gliomas by rapamycin coadministration, which acts to promote immune responses engaged by viral delivery.

Epstein-Barr virus associated primary intracranial leiomyoma in organ transplant recipient: case report and review of the literature

INTRODUCTION

A 45 year old female renal transplant recipient presented with headaches of 3 months duration. Clinical and radiological evaluation revealed an approximately 4x4 cm rounded, enhancing mass at the left temporal pole. At surgery, the mass had dural attachment and clinically, radiographically, and macroscopically resembled a meningioma. Histopathological analysis revealed a leiomyoma. Epstein-Barr virus (EBV) DNA was demonstrated within the tumour cell nuclei by the in situ hybridisation technique.

DISCUSSION

This is the first documentation of an EBV-associated primary intracranial leiomyoma in an organ transplant recipient and provides additional evidence of a possible relation between EBV infection and development of smooth-muscle tumours (SMT).

CONCLUSION

With increasing numbers of individuals being on long-term immuno-suppression, EBV-associated SMTs may be encountered more frequently in the future.

Epstein-Barr Virus DNA Quantification: An Adjunctive Diagnostic Marker for AIDS-Associated Lymphoma

We report an HIV-positive patient who developed a unilateral retinitis and subsequent intracranial lesions. The finding of Epstein Barr virus (EBV) DNA at a > 1-log greater concentration in the vitreous compared to blood raised the possibility of a primary CNS non-Hodgkin's lymphoma, which was subsequently confirmed on brain biopsy. EBV DNA quantification acted as a diagnostic marker that led to a change in the management of our patient.

Engineered herpes simplex viruses efficiently infect and kill CD133+ human glioma xenograft cells that express CD111

Oncolytic herpes simplex viruses (HSV) hold promise for therapy of glioblastoma multiforme (GBM) resistant to traditional therapies. We examined the ability of genetically engineered HSV to infect and kill cells that express CD133, a putative marker of glioma progenitor cells (GPC), to determine if GPC have an inherent therapeutic resistance to HSV. Expression of CD133 and CD111 (nectin-1), the major entry molecule for HSV, was variable in six human glioma xenografts, at initial disaggregation and after tissue culture. Importantly, both CD133+ and CD133- populations of glioma cells expressed CD111 in similar relative proportions in five xenografts, and CD133+ and CD133- glioma cell subpopulations were equally sensitive to killing in vitro by graded dilutions of wild-type HSV-1(F) or several different gamma(1)34.5-deleted viruses. GPC did not display an inherent resistance to HSV. While CD111 expression was an important factor for determining sensitivity of glioma cells to HSV oncolysis, it was not the only factor. Our findings support the notion that HSV will not be able to effectively enter, infect, and kill cells in tumors that have low CD111 expression (<20%). However, virotherapy with HSV may be very effective against CD111+ GPC resistant to traditional therapies.

Primary cerebral lymphomatoid granulomatosis: report of four cases and literature review

BACKGROUND

Lymphomatoid granulomatosis (LYG) is an angiocentric and angiodestructive lymphoreticular proliferation, which usually involves the lungs, but may also involve the central nervous system (CNS). Unique involvement of the CNS has been reported rarely. We report our experience with LYG confined to the brain and review the pertinent literature.

PATIENTS AND METHODS

From January 1995 to September 2007, we identified patients with isolated brain LYG through a search of the histopathology database of the Catholic University of Rome; medical and radiological data were analyzed. Immunophenotype, in situ hybridization analysis of EBV-encoded small RNAs (EBER ISH) and immunoglobulin rearrangement studies were performed on the pathological specimens.

RESULTS

Four patients with brain-LYG (male/female 1:1, mean age 44 years) underwent surgery in the study period. Subsequent therapy was tailored according to LYG grading. At the latest follow-up (range from 18 to 221 months), patient conditions had improved in all cases. EBER ISH was negative in all cases. Study of the IgH chain gene documented a monoclonal pattern in two cases.

CONCLUSIONS

CNS-LYG is a rare disease that should be considered in the differential diagnosis of both diffuse and space-occupying cerebral lesions. Primary cerebral LYG seems not to be associated with EBV and appears to have a better prognosis than systemic LYG with CNS localization, which is frequently EBV positive.

Brain tumor as an unusual presentation of posttransplant lymphoproliferative disorder

OBJECTIVES

Posttransplant lymphoproliferative disorder following solid organ transplant is a lifethreatening form of posttransplant malignancy. Its occurrence is typically associated with Epstein-Barr virus and profound immunosuppressive therapy. We describe a case of posttransplant lymphoproliferative disorder in the brain parenchyma, 4 years after renal transplant.

CASE REPORT

A 23-year-old man was evaluated for generalized headache 4 years after receiving a deceased donor renal transplant. After initial immunosuppression with tacrolimus and prednisolone, mycophenolate mofetil was added for maintenance immunosuppression. A tumor in the right occipitoparietal lobe was detected by magnetic resonance imaging and excised. Immunohistochemical testing of the tumor revealed B-cell marker and Epstein-Barr virus. After surgery, the dosage of immunosuppressive drugs was reduced, and the patient was treated with chemotherapy and radiotherapy. Our patient is well after treatment.

CONCLUSIONS

Reduction in immunosuppressive therapy is an important component of treatment for Epstein-Barr virus-positive posttransplant lymphoproliferative disorder and may lead to remission in early disease. If reduced immunosuppression fails to control early disease, cytotoxic chemotherapy, surgery and radiotherapy, antiviral therapies, and cell-based therapies are other options for treatment.

Case report: herpes simplex encephalitis in cancer patients

The manifestation of herpes simplex encephalitis in patients can often be interpreted as a possible brain tumor. In order to make a definite diagnosis, subsequent invasive testing is frequently required. In addition to other routine diagnostic measures, particular symptoms, especially those indicating that a patient is immunocompromised, should be considered as possible evidence indicating presence of this central nervous system (CNS) viral infection.