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Atypical teratoid/rhabdoid tumors (ATRTs) and primitive neuroectodermal tumors (PNETs) are two rare primary embryonal brain tumors, which are among the most frequent solid brain tumors in infants under one year old. The outcome for these children remains dismal, especially in ATRTs which have a 2-year overall survival below 20%. Therefore, we need to find out new efficient and safe therapeutic options for these children. Delta-24-RGD (DNX-2401 in the clinic) is an oncolytic adenovirus that has already been tested in Phase I/II clinical trials in patients affected by recurrent glioblastoma (NCT00805376; NCT01956734), demonstrating anti-tumor effect without any evidence of severe side effect associated with viral administration. Of interest for pediatric brain tumors, an ongoing Phase I trial using Delta-24-RGD for the treatment of diffuse intrinsic pontine gliomas (NCT03178032) has also demonstrated a safe profile in these children. For these reasons, we propose to evaluate the anti-tumor effect of Delta-24-RGD in preclinical models of ATRT and PNET. The virus was able to infect and replicate in tumor cell cultures (three models of ATRT and four of PNET), inducing a potent cytotoxic effect. In addition, this cytotoxicity resulted in the released the immunogenic cell death markers Hsp70, Hsp90, HMGB1 and ATP, as well as an increased calreticulin exposure in the outer cell surface. Although not conclusive, the presence of these markers suggest the triggering of an anti-tumor immune response. Intratumoral administration of the virus extended significantly the overall survival of mice bearing ATRT or PNET xenografts, leading to up to 40% of long-term survivors. We are currently setting up an intraventricular model of disseminated disease, since most of patients with ATRT actually die due to the presence of metastases. In conclusion, these results demonstrate that Delta-24-RGD could be a feasible therapeutic option for children with PNETs and AT/RTs.

9 p.-1 tab., Nowadays, more than 95 different Streptococcus pneumoniae serotypes are known, being less than one third responsible for the majority of severe pneumococcal infections. After the introduction of conjugate vaccines, a change in the epidemiology of the serotypes causinginvasive pneumococcal disease has been observed making the surveillance of circulating serotypes especially relevant. Some recent studies have used matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) technology to identify the most frequent pneumococcal serotypes that cause invasive disease. The objectives of this study were to evaluate the efficacy of previously described discriminatory peaks determinedby MALDI-TOF MS for the identification of serotypes 6B, 19F, 19A and 35B using reference and clinical isolates and to try to identify other discriminatory peaks for serotypes 11A, 19F and 19A using transformed pneumococcal strains. Most of the proposed peaks defined in the literature for the identification of serotypes 6B, 19F, 19A, 35B were not found in the spectra of the 10 reference isolates nor in those of the 60 clinical isolates tested corresponding to these four serotypes. The analysis and comparison of the mass spectra of genetically modified pneumococci (transformed strains) did not allow the establishment of new discriminatory peaks for serotypes 11A, 19F, and 19A. MALDI-TOF MS in the usual range of 2,000 to 20,000 m/z did not prove to be a valid technique for direct S. pneumoniae serotyping., This work was funded in part by a grant of the Centro de Investigación Biomédica en Red de Enfermedades Respiratorias (CIBERES), CB06/06/0056 and CB06/06/0003.

Pediatric high grade gliomas (pHGG), including diffuse intrinsic pontine gliomas (DIPGs), are aggressive tumors with a dismal outcome. Radiotherapy (RT) is part of the standard of care of these tumors; however, radiotherapy only leads to a transient clinical improvement. Delta-24-RGD is a genetically engineered tumor-selective adenovirus that has shown safety and clinical efficacy in adults with recurrent gliomas. In this work, we evaluated the feasibility, safety and therapeutic efficacy of Delta-24-RGD in combination with radiotherapy in pHGGs and DIPGs models. Our results showed that the combination of Delta-24-RGD with radiotherapy was feasible and resulted in a synergistic anti-glioma effect in vitro and in vivo in pHGG and DIPG models. Interestingly, Delta-24-RGD treatment led to the downregulation of relevant DNA damage repair proteins, further sensitizing tumors cells to the effect of radiotherapy. Additionally, Delta-24-RGD/radiotherapy treatment significantly increased the trafficking of immune cells (CD3, CD4+ and CD8+) to the tumor niche compared with single treatments. In summary, administration of the Delta-24-RGD/radiotherapy combination to pHGG and DIPG models is safe and significantly increases the overall survival of mice bearing these tumors. Our data offer a rationale for the combination Delta-24-RGD/radiotherapy as a therapeutic option for children with these tumors. Significance Delta-24-RGD/radiotherapy administration is safe and significantly increases the survival of treated mice. These positive data underscore the urge to translate this approach to the clinical treatment of children with pHGG and DIPGs. Electronic supplementary material The online version of this article (10.1186/s40478-019-0714-6) contains supplementary material, which is available to authorized users.

Cancer virotherapy is a paradigm-shifting treatment modality based on virus-mediated oncolysis and subsequent antitumor immune responses. Clinical trials of currently available virotherapies showed that robust antitumor immunity characterizes the remarkable and long-term responses observed in a subset of patients. These data suggest that future therapies should incorporate strategies to maximize the immunotherapeutic potential of oncolytic viruses. In this review, we highlight the recent evidence that the antiviral immunity of the patients may limit the immunotherapeutic potential of oncolytic viruses and summarize the most relevant approaches to strategically redirect the immune response away from the viruses and toward tumors to heighten the clinical impact of viro-immunotherapy platforms.

Current therapies for atypical teratoid/rhabdoid tumors (AT/RTs) are suboptimal, resulting in a 2-year OS below 20% and the development of severe side effects. Therefore, we need to explore alternative therapeutic approaches for this disease. Since the virus Delta24-RGD has already demonstrated its efficacy and safety as a therapeutic agent for brain tumors, including pediatric patients, here we propose to evaluate the anti-tumor effect of Delta24-RGD in AT/RT. In vitro, Delta24-RGD infects and replicates in AT/RT cultures followed by oncolysis, obtaining IC50 values below 1 PFU/cell. In vivo, a single local injection of Delta-24-RGD in three infratentorial AT/RT models (BT-12, CHLA-06 and CHLA-266) extended significantly the median OS (50 to 78 days BT-12; 21 to 31 days CHLA-06; 64 to 110 days CHLA-266). Delta-24-RGD also increased the survival of mice bearing supratentorial CHLA-266 tumors (from 93 to 132 days). Next, we evaluated the efficacy of Delta24-RGD in a model mimicking metastatic disease through intraventricular injection of BT-12-luciferase cells. Administration of Delta24-RGD inhibited tumor growth and development of metastases, leading to an increased OS and nearly 70% of long-term survivors. The interaction between Delta24-RGD and the immune system was evaluated in humanized mice models bearing CHLA-06. In this model, Delta24-RGD treatment extended OS (from 23 to 34 days) and we characterized the anti-tumor immune landscape in control and Delta24-RGD treated mice by transcriptional and functional analyses. These results underscore the potential of Delta24-RGD as a promising therapeutic choice for patients affected by AT/RT.

The objective of this trial is to determine the safety, tolerability, and toxicity of DNX-2401 in newly diagnosed DIPG patients (NCT03178032) followed by radiotherapy. Secondary endpoints are overall survival at 12 months, percentage of responses and induced immune response against tumor. Tumor biopsy was performed through the cerebellar peduncle, followed by intratumoral injection of DNX-2401 (N=12). Three patients were treated with 1x1010vp and given the lack of toxicity we escalated to 5x1010vp. The procedure was well tolerated and reduced tumor volume was demonstrated in all patients after combined treatment (virus + radiotherapy). We performed molecular studies (RNAseq and the Oncomine Childhood Research Panel from Thermo Fisher). The immune cell composition of the biopsies pre-virus injection was assessed using multiplexed quantitative immunofluorescence. T cells were hardly detectable in these tumors while macrophages were abundant. Using a multiplexed TCR-sequencing mRNA-based assay to analyze 18 available paired pre- and post-treatment samples from the trial, we detected increased clonal T cell diversity following treatment with the virus. We also measured pre and post treatment neutralizing antibodies and their relationship with survival. Finally, we performed functional studies using 2 cell lines isolated from patients included in this trial to assess the response to the virus (infectivity, viability, T-cell recognition). In summary, the virus has shown safety and efficacy in some patients. The information obtained in this clinical study would aid understanding the response of DIPG patients to viral therapies and, therefore, to better tailor this strategy to improve the survival of these patients.

Diffuse intrinsic pontine glioma (DIPG) is an aggressive brain tumour, being the leading cause of paediatric death caused by cancer. Despite all the advances made regarding effective therapies, the survival is dismal. Our lab has engineered the oncolytic virus Delta-24-ACT armed with the costimulatory ligand 41BBL in order to increase the antitumoral effect of the adenovirus. 41BB is a costimulatory receptor which promotes the expansion of activated T cells and the generation and maintenance of CD8 T memory cells. Therefore, we propose the use of Delta-24-ACT as a therapeutic approach for DIPG tumours. We observed that Delta-24-ACT is able to infect and replicate in NP53 and PDGFB-driven, two DIPG murine cell lines. Furthermore, 41BBL is expressed in the membranes of the infected cells and results with immunogenic cell death as shown by the different DAMPs. Injection of Delta-24-ACT in DIPG model was safe, showed no sign of toxicity and led to a significantly increase in the median overall survival, generating anti-glioma memory in long-term survivors. Mechanistic experiments, showed an increase of T cell infiltration (mainly CD8), decrease of proliferating cells and a reduction of the number of vessels in FFPE brain samples in the treated mice. We are currently performing nanostring analyses to assess the changes in the transcriptional immune phenotype of treated versus control mice. In summary, our data suggest that Delta-24-ACT is safe and induces a potent antitumor immune response in DIPG models mainly based in the activation of CD8 lymphocytes recruited by the viral activity.

Pediatric high-grade gliomas (pHGG) are heterogeneous brain tumors for which new specific diagnostic/prognostic biomarkers are needed. In this study, we aimed to identify new pHGG subgroup specific biomarkers by exploiting exosomes, known vehicles of oncogenic signals. We used plasma from 23 patients (including 6 controls) and conditioned medium from 12 patient-derived cell-lines, representing all locational and molecular subgroups. Upon exosome isolation, total RNA was extracted and miRNAs were assessed using a PCR Panel. Analysis of plasma miRNome showed that tumor exosomal samples were largely clustered together, independently from their locational and/or molecular subgroup. We identified 20 significantly upregulated and 25 downregulated miRNAs compared to controls. Interestingly, 27 miRNAs were expressed only in tumors. Furthermore, the unsupervised clustering showed a clear separation based on locational (hemispheric vs pontine) and mutational (WT vs H3.3G34R or H3.3G34R vs H3K27M) subgroup comparisons, with the identification of distinct miRNomes underlying the key role of location and mutations in defining the pHGG exosomal miRNA profile. This was further confirmed analyzing the miRNOme from cell-line derived exosomes. Moreover, we identified a pool of significantly differentially regulated miRNAs in diagnose vs relapse and biopsy vs autopsy cell-lines. Most importantly, when comparing hemispheric vs pontine and H3.3G34R vs H3.3K27M, we identified respectively four and three miRNas equally dysregulated and in common between plasma and cell-lines. Those were strongly associated mainly to transcriptional regulation and targeting TTC9, linked to cancer invasion and metastasis. Based on this, we suggest exosomal miRNAs as a powerful new pHGG diagnostic/prognostic tool.

Purpose: Osteosarcoma is the most common malignant bone tumor in children and adolescents. Despite aggressive chemotherapy, more than 30% of patients do not respond and develop bone or lung metastasis. Oncolytic adenoviruses engineered to specifically destroy cancer cells are a feasible option for osteosarcoma treatment. VCN-01 is a replication-competent adenovirus specifically engineered to replicate in tumors with a defective RB pathway, presents an enhanced infectivity through a modified fiber and an improved distribution through the expression of a soluble hyaluronidase. The aim of this study is to elucidate whether the use of VCN-01 would be an effective therapeutic strategy for pediatric osteosarcoma. Experimental Design: We used osteosarcoma cell lines established from patients with metastatic disease (531MII, 678R, 588M, and 595M) and a commercial cell line (143B). MTT assays were carried out to evaluate the cytotoxicity of VCN-01. Hexon assays were used to evaluate the replication of the virus. Western blot analysis was performed to assess the expression levels of viral proteins and autophagic markers. The antitumor effect of VCN-01 was evaluated in orthotopic and metastatic osteosarcoma murine animal models. Results: This study found that VCN-01, a new generation genetically modified oncolytic adenovirus, administered locally or systemically, had a potent antisarcoma effect in vitro and in vivo in mouse models of intratibial and lung metastatic osteosarcoma. Moreover, VCN-01 administration showed a safe toxicity profile. Conclusions: These results uncover VCN-01 as a promising strategy for osteosarcoma, setting the bases to propel a phase I/II trial for kids with this disease. Clin Cancer Res; 22(9); 2217–25. ©2015 AACR.

Glioblastoma is the most frequent malignant brain tumor. Even with aggressive treatment, prognosis for patients is poor. One characteristic of glioblastoma cells is its intrinsic resistance to apoptosis. Therefore, drugs that induce alternative cell deaths could be interesting to evaluate as alternative therapeutic candidates for glioblastoma. Salinomycin (SLM) was identified through a chemical screening as a promising anticancer drug, but its mechanism of cell death remains unclear. In the present work we set out to elucidate how SLM causes cell death in glioblastoma cell lines (both established cell lines and brain tumor stem cell lines), aiming to find a potential antitumor candidate. In addition, we sought to determine the mechanism of action of SLM so that this mechanism can be can be exploited in the fight against cancer. Our data showed that SLM induces a potent endoplasmic reticulum (ER) stress followed by the trigger of the unfolded protein response (UPR) and an aberrant autophagic flux that culminated in necrosis due to mitochondria and lysosomal alterations. Of importance, the aberrant autophagic flux was orchestrated by the production of Reactive Oxygen Species (ROS). Alleviation of ROS production restored the autophagic flux. Altogether our data suggest that in our system the oxidative stress blocks the autophagic flux through lipid oxidation. Importantly, oxidative stress could be instructing the type of cell death in SLM-treated cells, suggesting that cell death modality is a dynamic concept which depends on the cellular stresses and the cellular mechanism activated.

Background Endoplasmic reticulum (ER) stress results from protein misfolding imbalance and has been postulated as a therapeutic strategy. ER stress activates the unfolded protein response which leads to a complex cellular response, including the upregulation of aberrant protein degradation in the ER, with the goal of resolving that stress. O(6)-methylguanine DNA methyltransferase (MGMT), N-methylpurine DNA glycosylase (MPG), and Rad51 are DNA damage repair proteins that mediate resistance to temozolomide in glioblastoma. In this work we sought to evaluate whether ER stress-inducing drugs were able to downmodulate DNA damage repair proteins and become candidates to combine with temozolomide. Methods MTT assays were performed to evaluate the cytotoxicity of the treatments. The expression of proteins was evaluated using western blot and immunofluorescence. In vivo studies were performed using 2 orthotopic glioblastoma models in nude mice to evaluate the efficacy of the treatments. All statistical tests were 2-sided. Results Treatment of glioblastoma cells with ER stress-inducing drugs leads to downregulation of MGMT, MPG, and Rad51. Inhibition of ER stress through pharmacological treatment resulted in rescue of MGMT, MPG, and Rad51 protein levels. Moreover, treatment of glioblastoma cells with salinomycin, an ER stress-inducing drug, and temozolomide resulted in enhanced DNA damage and a synergistic antitumor effect in vitro. Of importance, treatment with salinomycin/temozolomide resulted in a significant antiglioma effect in 2 aggressive orthotopic intracranial brain tumor models. Conclusions These findings provide a strong rationale for combining temozolomide with ER stress-inducing drugs as an alternative therapeutic strategy for glioblastoma.

Glioblastoma recurrence after treatment with the anti-vascular endothelial growth factor (VEGF) agent bevacizumab is characterized by a highly infiltrative and malignant behavior that renders surgical excision and chemotherapy ineffective. Our group has previously reported that Tie2-expressing monocytes (TEMs) are aberrantly present at the tumor/normal brain interface after anti-VEGF therapies and their significant role in the invasive outgrowth of these tumors. Here, we aimed to further understand the mechanisms leading to this pro-invasive tumor microenvironment. Examination of a U87MG xenogeneic glioma model and a GL261 murine syngeneic model showed increased tumor expression of angiopoietin 2 (Ang2), a natural ligand of Tie2, after anti-angiogenesis therapies targeting VEGF or VEGF receptor (VEGFR), as assessed by immunohistochemical analysis, immunofluorescence analysis, and enzyme-linked immunosorbent assays of tumor lysates. Migration and gelatinolytic assays showed that Ang2 acts as both a chemoattractant of TEMs and an enhancing signal for their tumor-remodeling properties. Accordingly, in vivo transduction of Ang2 into intracranial gliomas increased recruitment of TEMs into the tumor. To reduce invasive tumor outgrowth after anti-angiogenesis therapy, we targeted the Ang-Tie2 axis using a Tie2 decoy receptor. Using syngeneic models, we observed that overexpression of soluble Tie2 within the tumor prevented the recruitment of TEMs to the tumor and the development of invasion after anti-angiogenesis treatment. Taken together, these data indicate an active role for the Ang2-Tie2 pathway in invasive glioma recurrence after anti-angiogenesis treatment and provide a rationale for testing the combined targeting of VEGF and Ang-Tie2 pathways in patients with glioblastoma.

Pediatric diffuse midline gliomas-H3-K27M-mutant are aggressive brain tumours that arise during childhood. Despite new advances in genomic knowledge and the significant number of clinical trial testing new targeted therapies, patient outcome is still insufficient. Cancer immunotherapy is opening new therapeutic options representing a hope for this orphan disease. Aptamers are single-stranded nucleic acid ligands design to achieve a remarkable affinity and specificity to their targets, comparable to antibodies. TIM-3, is a potential immune checkpoint target, typically involved in T-cell exhaustion. Recent studies showed that TIM-3 is also expressed in tumour and glial cells and it plays an important role in brain tumour responses mediated by myeloid cells. In this work, we examined the anti-tumour effect of an aptamer against TIM-3 alone or in combination with radiotherapy. Of importance, we tested TIM-3 aptamer in a murine glioma and DIPG model, where we not observed any toxicity. TIM-3 administration increased overall survival but was unable to control the disease. Of importance, TIM-3 combination with radiotherapy improved the overall survival of treated mice when compared with single treatments leading to 50% of long-term survivors. TIM-3 aptamer administration increase T-infiltration in the tumour site compared to non-treated or library control. Mechanistic studies performed on day 16 showed an increase in CD8 effector cells, a decrease in T-regulators Foxp3+ cells and an increase in IFN-gamma expression suggesting the triggering of an antitumor-immune response. Rechallenge experiments demonstrated immune memory in the long-term responders that led to reject tumour re-implantation, confirming that TIM-3 aptamer treatment in combination with RT elicits specific antitumor immunity in mouse glioma models. These results suggest that immuno-therapies approaches in combination with radiotherapy would be worth exploring in the treatment of deadly DMG-H3K27-Mutant tumours.

Oncolytic viruses have become promising therapeutic candidates to treat gliomas. Our group has developed Delta-24-ACT, an oncolytic adenovirus armed with the positive costimulatory ligand 4-1BBL which is capable to trigger the activation of T cells and thereby increase their antitumor immune response. Here we evaluate the anti-glioma effect of Delta-24-ACT alone or in combination with an immune checkpoint inhibitor. We observed that Delta-24-ACT was able to infect and kill murine glioma (GL261-5 and CT-2A) and also human glioma cell lines (U87-MG and U251-MG), while maintaining its replication in the latter. Of importance, Delta-24-ACT infection resulted in 4-1BBL expression on the membrane of glioma cells. Moreover, this ligand was functional and was able to stimulate CD8 lymphocytes in vitro, suggesting the potential of Delta-24-ACT to trigger an effective immune response. Furthermore, in vivo Delta-24-ACT showed anti-tumour effect in two murine glioma models by significantly increasing the median survival time and leading to long-term survivors. Mechanistic studies demonstrated an increase of the T cell infiltration and the activation of different immune cell populations by flow cytometry and a decrease of proliferative cells and tumour vessels by immunohistochemistry on FFPE brain samples. Importantly, the infiltrating lymphocytes also showed signs of exhaustion increasing the amount of IL-10 and the expression of PD-1. To overcome this exhaustion we combined Delta-24-ACT with an anti-PD-1 antibody. Evaluation of this combination in vivo further increased the median survival time of treated tumor-bearing mice and resulted in 50% long-term survivors. Rechallenge studies with the same cell line showed that combination treatment effectively protected these animals of developing tumors and therefore, the acquisition of immune memory. In summary, our data demonstrated that Delta-24-ACT induces a potent anti-tumour effect in vitro and in vivo as a result of the recruitment of immune cell populations modulating the immunosuppressive tumour microenvironment of glioma.

Despite our increased understanding of Diffuse Intrinsic Pontine Glioma (DIPG) the outcome remains dismal. Recently we showed that the virus Delta-24-RGD (DNX-2401 in the clinic) was effective in preclinical models of DIPG and had the ability to trigger an antitumor immune response. These data allowed us to propel a phase I clinical trial for newly diagnosed DIPGs (NCT03178032) where the patients received an intratumoral viral injection followed by standard radiotherapy. The main objective is to determine the safety, tolerability, and toxicity of DNX-2401. Secondary endpoints are overall survival at 12 months, percentage of responses and induced immune response against tumor. Tumor biopsy was performed through the cerebellar peduncle, followed by intratumoral injection of DNX-2401 (N=12). Three patients were treated with the D1=1x1010vp and because the lack of toxicity we escalated to the D2= 5x1010vp. The procedure was well tolerated and safe. All patients displayed a reduced tumor volume after combined treatment. We performed molecular studies in 9 out of the 12 patients. The immune cell composition of the biopsies was assessed using multiplexed quantitative immunofluorescence. T cells were hardly noticeable in these tumors while macrophages were abundant. We detected increased clonal T cell diversity following treatment with virus in peripheral blood lymphocytes when compared paired pre- and post-treatment samples from the trial. In addition, we measure pre and post treatment neutralizing antibodies and its relationship with survival. Finally, we performed functional studies using 2 cell lines isolated from patients included in this trial to assess the response to the virus (infectivity, viability, T-cell recognition). Overall, the administration of DNX2401 was safe, feasible and therapeutically beneficial in a subgroup of patients. This trial constitutes a proof of principle that aids to understand the response of DIPGs to viral therapies allowing to set the bases to improve this strategy for DIPG.

Mature B-cell non-Hodgkin lymphoma (B-NHL) constitutes a group of heterogeneous malignant lymphoproliferative diseases ranging from indolent to highly aggressive forms. Although the survival after chemo-immunotherapy treatment of mature B-NHL has increased over the last years, many patients relapse or remain refractory due to drug resistance, presenting an unfavorable prognosis. Hence, there is an urgent need to identify new prognostic markers and therapeutic targets. Podocalyxin (PODXL), a sialomucin overexpressed in a variety of tumor cell types and associated with their aggressiveness, has been implicated in multiple aspects of cancer progression, although its participation in hematological malignancies remains unexplored. New evidence points to a role for PODXL in mature B-NHL cell proliferation, survival, migration, drug resistance, and metabolic reprogramming, as well as enhanced levels of PODXL in mature B-NHL. Here, we review the current knowledge on the contribution of PODXL to tumorigenesis, highlighting and discussing its role in mature B-NHL progression.

Background Osteosarcoma is the most common malignant bone tumor in children and young adults that produces aberrant osteoid. The aim of this study was to assess the utility of 2-deoxy-2-[18F-] fluoro-D-glucose ([18F] FDG) and sodium [18F] Fluoride (Na [18F] F) PET scans in orthotopic murine models of osteosarcoma to describe the metabolic pattern of the tumors, to detect and diagnose tumors and to evaluate the efficacy of a new treatment based in oncolytic adenoviruses. Methods Orthotopic osteosarcoma murine models were created by the injection of 143B and 531MII cell lines. [18F]FDG and Na [18F] F PET scans were performed 30 days (143B) and 90 days (531MII) post-injection. The antitumor effect of two doses (107 and 108 pfu) of the oncolytic adenovirus VCN-01 was evaluated in 531 MII model by [18F] FDG PET studies. [18F] FDG uptake was quantified by SUVmax and Total Lesion Glycolysis (TLG) indexes. For Na [18F] F, the ratio tumor SUVmax/hip SUVmax was calculated. PET findings were confirmed by histopathological techniques. Results The metabolic pattern of tumors was different between both orthotopic models. All tumors showed [18F] FDG uptake, with a sensitivity and specificity of 100%. The [18F] FDG uptake was significantly higher for the 143B model (p

The identification of circulating biomarkers by non-invasive methods would be helpful for glioma detection and response assessment. Strong evidences have shown that GBM cells release microvesicles containing proteins and RNA. We have previously demonstrated that exosomes isolated from the serum of GBM patients had an increased expression of RNU6-1 compared to control samples; therefore it could serve as a non-invasive diagnostic biomarker for GBM. In this study, we set to investigate the role of RNU6-1 as a differential biomarker of GBM versus other brain diseases with similar radiological features. RNU6-1 expression was analysed by digital droplet PCR (ddPCR) in circulating exosomes from serum samples of GBM patients (n=18), healthy controls (n=28), and patients with different brain lesions: subacute stroke (n=30), acute-subacute haemorrhage (n=29), acute demyelinating lesions (n=19), brain metastases (n=21) and Primary CNS Lymphomas (PCNSL) (n=12). We observed that the expression of RNU6-1 was significantly higher in GBM patients (412 ± 550.48 copies/20µL) than in healthy controls (150 ± 224.35 copies/20µL; p=0.039) validating our preceding results. Furthermore, RNU6-1 levels were increased in exosomes from GBM patients than in exosomes from patients with non-neoplastic lesions (stroke [223 ± 709.8 copies/20µL; p=0,067], haemorrhage [127 ± 198.7 copies/20µL; p=0.010], demyelinating lesions [111.5 ± 250.35 copies/20µL; p=0.019]) and PCNSL [18.15 ± 245.7 copies/20µL; p=0.004]). Contrary, RNU6-1 levels were similar between brain metastases and GBM patients [325 ± 632 copies/20µL; p=0.573]. In addition, assessing RNU6-1 as a predictive marker of GBM by ROC curves analysis, we demonstrated that RNU6-1 was a robust diagnostic biomarker of GBM compared to subacute stroke [AUC=0.659; p=0.004], acute/subacute haemorrhage [AUC=0.724; p=0.006], acute demyelinating lesions [AUC=0.728; p=0.011] and PCNSL [AUC=0.814; p

INTRODUCTION. With a view to finding new compounds with improved antitumoral activity and reduced secondary effects, our group, using theoretical structure-activity studies, has designed several analogues and derivatives of diarylsulfonilureas (1). These compounds have been synthesized and tested “in vitro” on a panel of human tumor cell lines and showed an antitumoral activity (2). In the present work, we have characterized the mechanisms involved in the cell death process induced by one of these products called E3 in a CCRF-CEM cell line.

In recent years, we have seen an important progress in our comprehension of the molecular basis of pediatric brain tumors (PBTs). However, they still represent the main cause of death by disease in children. Due to the poor prognosis of some types of PBTs and the long-term adverse effects associated with the traditional treatments, oncolytic viruses (OVs) have emerged as an interesting therapeutic option since they displayed safety and high tolerability in pre-clinical and clinical levels. In this review, we summarize the OVs evaluated in different types of PBTs, mostly in pre-clinical studies, and we discuss the possible future direction of research in this field. In this sense, one important aspect of OVs antitumoral effect is the stimulation of an immune response against the tumor which is necessary for a complete response in preclinical immunocompetent models and in the clinic. The role of the immune system in the response of OVs needs to be evaluated in PBTs and represents an experimental challenge due to the limited immunocompetent models of these diseases available for pre-clinical research.

Background: Glioblastoma, the most aggressive primary brain tumor, is genetically heterogeneous. Alternative splicing (AS) plays a key role in numerous pathologies, including cancer. The objectives of our study were to determine whether aberrant AS could play a role in the malignant phenotype of glioma and to understand the mechanism underlying its aberrant regulation. Methods: We obtained surgical samples from patients with glioblastoma who underwent 5-aminolevulinic fluorescence-guided surgery. Biopsies were taken from the tumor center as well as from adjacent normal-appearing tissue. We used a global splicing array to identify candidate genes aberrantly spliced in these glioblastoma samples. Mechanistic and functional studies were performed to elucidate the role of our top candidate splice variant, BAF45d, in glioblastoma. Results: BAF45d is part of the switch/sucrose nonfermentable complex and plays a key role in the development of the CNS. The BAF45d/6A isoform is present in 85% of over 200 glioma samples that have been analyzed and contributes to the malignant glioma phenotype through the maintenance of an undifferentiated cellular state. We demonstrate that BAF45d splicing is mediated by polypyrimidine tract-binding protein 1 (PTBP1) and that BAF45d regulates PTBP1, uncovering a reciprocal interplay between RNA splicing regulation and transcription. Conclusions: Our data indicate that AS is a mechanism that contributes to the malignant phenotype of glioblastoma. Understanding the consequences of this biological process will uncover new therapeutic targets for this devastating disease.

Gliomas are the most common and aggressive brain tumors and despite advances in their therapeutic management they remain fatal. Radically, different therapeutic approaches are needed to treat this aggressive disease. Oncolytic viruses that intrinsically kill cancer cells or that have been genetically engineered to specifically destroy this population are becoming a viable therapeutic options for gliomas. A number of preclinical studies have demonstrated the efficacy of oncolytic viruses as a therapeutic strategy for gliomas. Those studies have led to a number of clinical trials using oncolytic virus for glioma treatment. In this chapter, we review the different viruses (adenovirus, herpes virus, parvovirus, poliovirus, reovirus, newcastle disease virus, retrovirus, and measles viruses) that have been evaluated preclinically and clinically for the treatment of glioma.

Purpose DNX-2401 (Delta-24-RGD; tasadenoturev) is a tumor-selective, replication-competent oncolytic adenovirus. Preclinical studies demonstrated antiglioma efficacy, but the effects and mechanisms of action have not been evaluated in patients. Methods A phase I, dose-escalation, biologic-end-point clinical trial of DNX-2401 was conducted in 37 patients with recurrent malignant glioma. Patients received a single intratumoral injection of DNX-2401 into biopsy-confirmed recurrent tumor to evaluate safety and response across eight dose levels (group A). To investigate the mechanism of action, a second group of patients (group B) underwent intratumoral injection through a permanently implanted catheter, followed 14 days later by en bloc resection to acquire post-treatment specimens. Results In group A (n = 25), 20% of patients survived > 3 years from treatment, and three patients had a ≥ 95% reduction in the enhancing tumor (12%), with all three of these dramatic responses resulting in > 3 years of progression-free survival from the time of treatment. Analyses of post-treatment surgical specimens (group B, n = 12) showed that DNX-2401 replicates and spreads within the tumor, documenting direct virus-induced oncolysis in patients. In addition to radiographic signs of inflammation, histopathologic examination of immune markers in post-treatment specimens showed tumor infiltration by CD8+ and T-bet+ cells, and transmembrane immunoglobulin mucin-3 downregulation after treatment. Analyses of patient-derived cell lines for damage-associated molecular patterns revealed induction of immunogenic cell death in tumor cells after DNX-2401 administration. Conclusion Treatment with DNX-2401 resulted in dramatic responses with long-term survival in recurrent high-grade gliomas that are probably due to direct oncolytic effects of the virus followed by elicitation of an immune-mediated antiglioma response.

Adenovirus Delta-24-RGD has shown a remarkable efficacy in a phase I clinical trial for glioblastoma. Delta-24-RGD induces autophagy in glioma cells, however, the molecular derangements associated with Delta-24-RGD infection remains poorly understood. Here, proteomics was applied to characterize the glioma metabolic disturbances soon after Delta-24-RGD internalization and late in infection. Minutes post-infection, a rapid survival reprogramming of glioma cells was evidenced by an early c-Jun activation and a time-dependent dephosphorylation of multiple survival kinases. At 48 h post-infection (hpi), a severe intracellular proteostasis impairment was characterized, detecting differentially expressed proteins related to mRNA splicing, cytoskeletal organization, oxidative response, and inflammation. Specific kinase-regulated protein interactomes for Delta-24-RGD-modulated proteome revealed interferences with the activation dynamics of protein kinases C and A (PKC, PKA), tyrosine-protein kinase Src (c-Src), glycogen synthase kinase-3 (GSK-3) as well as serine/threonine-protein phosphatases 1 and 2A (PP1, PP2A) at 48hpi, in parallel with adenoviral protein overproduction. Moreover, the late activation of the nuclear factor kappa B (NF-κB) correlates with the extracellular increment of specific cytokines involved in migration, and activation of different inflammatory cells. Taken together, our integrative analysis provides further insights into the effects triggered by Delta-24-RGD in the modulation of tumor suppression and immune response against glioma. Significance: The current study provides new insights regarding the molecular mechanisms governing the glioma metabolism during Delta-24-RGD oncolytic adenoviral therapy. The compilation and analysis of intracellular and extracellular proteomics have led us to characterize: i) the cell survival reprogramming during Delta-24-RGD internalization, ii) the proteostatic disarrangement induced by Delta-24-RGD during the autophagic stage, iii) the protein interactomes for Delta-24-RGD-modulated proteome, iv) the regulatory effects on kinase dynamics induced by Delta-24-RGD late in infection, and v) the overproduction of multitasking cytokines upon Delta-24-RGD treatment. We consider that the quantitative molecular maps generated in this study may establish the foundations for the development of complementary adenoviral based-vectors to increase the potency against glioma. This work was funded by grants from the Spanish Ministry of Economy and Competitiveness (MINECO) (Ref. SAF2014-59340-R To ES), the Department of Economic Development from Government of Navarra (Ref. PC023-PC024, PC025, PC081-82 and PI059 to ES and PI031 to JFI), the Instituto de Salud Carlos III and Fondos Feder Europeos (PI16/00066 to MMA), the Spanish Ministry of Science and Innovation (IEDI-2015-00638 to MMA), the Department of Health of the Government of Navarra (to MMA), the Basque Foundation for Health Research (BIOEF, BIO13/CI/005 to MMA), Asociación Pablo Ugarte-Fuerza, Julen (to MMA). AGM was supported by PEJ-2014-A-61949 (MINECO), and a pre-doctoral fellowship from Public University of Navarra (UPNA). The Proteomics Unit of Navarrabiomed is a member of Proteored, PRB3-ISCIII, and is supported by grant PT17/0019/0009, of the PE I+D+I 2013-2016 funded by ISCIII and FEDER.

// Andrea Gonzalez-Morales 1, 2, 3 , Aintzane Zabaleta 2, 4 , Elizabeth Guruceaga 2, 5 , Marta M. Alonso 2, 6, 7 , Marc Garcia-Moure 2, 6, 7 , Joaquin Fernandez-Irigoyen 1, 2, 3, * , Enrique Santamaria 1, 2, 3, * 1 Clinical Neuroproteomics Group, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Publica de Navarra (UPNA), Irunlarrea, Pamplona, Spain 2 IDISNA, Navarra Institute for Health Research, Pamplona, Spain 3 Proteored-ISCIII, Proteomics Unit, Navarrabiomed, Complejo Hospitalario de Navarra (CHN), Universidad Publica de Navarra (UPNA), Irunlarrea, Pamplona, Spain 4 Oncohematology Area, University Hospital of Navarra, Center for Applied Medical Research, CIBERONC, Pamplona, Spain 5 Bioinformatics Unit, Center for Applied Medical Research, University of Navarra, Pamplona, Spain 6 Program in Solid Tumors and Biomarkers, Foundation for the Applied Medical Research, Pamplona, Spain 7 Department of Pediatrics, University Hospital of Navarra, Pamplona, Spain * These authors share senior authorship Correspondence to: Enrique Santamaria, email: esantamma@navarra.es Keywords: adenovirus; Delta-24RGD infection; proteomics; glioma Received: February 06, 2018 Accepted: June 22, 2018 Published: July 24, 2018 ABSTRACT Glioblastoma multiforme (GBM) is the most common and aggressive type of malignant glioma. Oncolytic adenoviruses are being modified to exploit the aberrant expression of proteins in tumor cells to increase the antiglioma efficacy. E1A mutant adenovirus Delta-24-RGD (DNX-2401) has shown a favorable toxicity profile and remarkable efficacy in a first-in-human phase I clinical trial. However, the comprehensive modulation of glioma metabolism in response to Delta-24-RGD infection is poorly understood. Integrating mass spectrometry based-quantitative proteomics, physical and functional interaction data, and biochemical approaches, we conducted a cell-wide study of cytosolic, nuclear, and secreted glioma proteomes throughout the early time course of Delta-24-RGD infection. In addition to the severe proteostasis impairment detected during the first hours post-infection (hpi), Delta-24-RGD induces a transient inhibition of signal transducer and activator of transcription 3 (STAT3), and transcription factor AP-1 (c-JUN) between 3 and 10hpi, increasing the nuclear factor kappa B (NF-κB) activity at 6hpi. Furthermore, Delta-24-RGD specifically modulates the activation dynamics of protein kinase C (PKC), extracellular signal–regulated kinase 1/2 (ERK1/2), and p38 mitogen-activated protein kinase (p38 MAPK) pathways early in infection. At extracellular level, Delta-24-RGD triggers a time –dependent dynamic production of multitasking cytokines, and chemotactic factors, suggesting potential pleiotropic effects on the immune system reactivation. Taken together, these data help us to understand the mechanisms used by Delta-24-RGD to exploit glioma proteome organization. Further mining of this proteomic resource may enable design and engineering complementary adenoviral based-vectors to increase the specificity and potency against glioma.

Posterior fossa ependymoma comprise three distinct molecular variants, termed PF-EPN-A (PFA), PF-EPN-B (PFB), and PF-EPN-SE (subependymoma). Clinically, they are very disparate and PFB tumors are currently being considered for a trial of radiation avoidance. However, to move forward, unraveling the heterogeneity within PFB would be highly desirable. To discern the molecular heterogeneity within PFB, we performed an integrated analysis consisting of DNA methylation profiling, copy-number profiling, gene expression profiling, and clinical correlation across a cohort of 212 primary posterior fossa PFB tumors. Unsupervised spectral clustering and t-SNE analysis of genome-wide methylation data revealed five distinct subtypes of PFB tumors, termed PFB1-5, with distinct demographics, copy-number alterations, and gene expression profiles. All PFB subtypes were distinct from PFA and posterior fossa subependymomas. Of the five subtypes, PFB4 and PFB5 are more discrete, consisting of younger and older patients, respectively, with a strong female-gender enrichment in PFB5 (age: p = 0.011, gender: p = 0.04). Broad copy-number aberrations were common; however, many events such as chromosome 2 loss, 5 gain, and 17 loss were enriched in specific subtypes and 1q gain was enriched in PFB1. Late relapses were common across all five subtypes, but deaths were uncommon and present in only two subtypes (PFB1 and PFB3). Unlike the case in PFA ependymoma, 1q gain was not a robust marker of poor progression-free survival; however, chromosome 13q loss may represent a novel marker for risk stratification across the spectrum of PFB subtypes. Similar to PFA ependymoma, there exists a significant intertumoral heterogeneity within PFB, with distinct molecular subtypes identified. Even when accounting for this heterogeneity, extent of resection remains the strongest predictor of poor outcome. However, this biological heterogeneity must be accounted for in future preclinical modeling and personalized therapies.

Delta-24-RGD (DNX-2401 in the clinic) has been tested for adult glioblastoma presenting a safe profile and promising efficacy. Our group has showed that the virus is safe and effective in preclinical models of pHGG and DIPG. Moreover, we showed that the virus is able to trigger an antitumor immune response. These results allowed us to propel a phase I clinical trial for newly diagnosed DIPGs (NCT03178032) where the patients received an intratumoral injection of DNX-2401 (N=12). Tumor biopsy is performed through the cerebellar peduncle, followed by virus injection using a cannula that prevents the reflux. The trial is uncontrolled, unicentric with a 3 + 3 design. The objective of this trial is to determine the safety, tolerability, and toxicity of DNX-2401 in subjects with DIPG. Secondary endpoints are overall survival at 12 months (OS12), percentage of responses and induced immune response against tumor. To date 9 patients have been treated within the trial. Three patients were treated with the D1=1x1010vp and because the lack of toxicity we escalated to the D2= 5x1010vp. The procedure was well tolerated and safe. Patients were home 3–4 days after the injection. All the patients displayed a reduced tumor volume after combined treatment. We performed molecular studies in 8 out of the 9 patients (RNAseq and a thermofisher pediatric panel). Subsequently we evaluated the immune cell composition in the tumor using multiplexed quantitative immunofluorescence on the biopsies pre-virus injection. T cells were hardly noticeable in these tumors while macrophages were abundant. Using a multiplexed TCR-sequencing mRNA-based assay to analyze 18 available paired pre- and post-treatment samples from the trial, we detected increased clonal T cell diversity following treatment with virus. In addition, we are assessing the existence of pre and post treatment neutralizing antibodies and its relationship with survival. Finally, we have performed functional studies using 2 cell lines isolated from patients included in this trials and confronting them with T-cells isolated from peripheral blood of the same patients before and after the treatment with the virus. Information acquired within this clinical study would aid to understand the response of DIPGs to viral therapies and therefore to better tailor this strategy to improve the survival of pediatric brain tumors.

BACKGROUND Glioblastoma (GBM) and Alzheimer’s disease (AD) are frequent among the elderly: about 50% of all GBM patients are 65 years or older, and 5–10% of people above this age threshold suffer from AD. MATERIAL AND METHODS We describe the case of an elderly patient with newly diagnosed GBM who developed a rapidly progressive severe dementia immediately following concomitant radio-chemotherapy. A purposed retrospective analysis of the surgical sample revealed Alzheimer pathology. RESULTS A 69-year old woman with no relevant past-medical history was diagnosed with a right temporo-parietal GBM on May 2017, with wild-type IDH1R132H gene and methylated MGMTP. After complete resection she received radiotherapy (60 Gy in 30 fractions) and concomitant chemotherapy with Temozolomide 75 mg/m2/day. During the last weeks of concomitant radio-chemotherapy and further on the patient developed a progressive neurological worsening with severe cognitive dysfunction, gait impairment and sphincter incontinence, becoming severely disabled and requiring continuous assistance. Brain MRI exams showed no signs of tumor recurrence, with focal white matter changes consisting on T2/FLAIR hyperintensities within the radiation field, enlarged sulci and ventriculomegaly. Underlying infectious and metabolic disorders, non-convulsive epileptic status and normal-pressure hydrocephalus were ruled out. Facing this situation the patient relatives were purposely asked for previous cognitive symptoms, and described very mild complaints of short-term memory loss during the previous year. Aiming at investigating the possibility of an underlying AD, focused examination of the surgical sample revealed the presence of frequent neuritic plaques, a neuropathological hallmark of AD. The patient developed a severe dementia with akinetic mutism by September 2017. Without evidence of tumor recurrence despite lack of adjuvant chemotherapy, she died of aspiration pneumonia on January 2019. CONCLUSION A unique retrospective study including elderly GBM patients treated only with surgery revealed that Alzheimer disease pathology was present in 42% of them. This case illustrates the need for actively addressing the previous cognitive status of elderly patients with GBM. Histopathological assessment of Alzheimer pathology might also be considered in this specific population. In positive cases, particularly in those with methylated MGMTP, radiotherapy should be avoided and treatment alone with Temozolomide might be considered.

Despite our increased understanding of the genetic make-up and new therapies for pediatric high grade glioma (pHGG) and Diffuse Intrinsic Pontine Glioma (DIPG) the outcome remains grim. Delta-24-RGD (DNX-2401 in the clinic) has been tested for adult glioblastoma presenting a safe profile and promising efficacy. The objective of this study was to evaluate the suitability of DNX-2401 as treatment for pHGG/DIPGs. Our results showed that DNX-2401 exerts a potent antitumor effect in pHGG (n=5) and DIPG (n=6) cell lines in vitro and in vivo. Our clinical trial experience with DNX-2401 in adult glioblastoma underscored the importance of the immune system in durable responses observed in patients. DNX-2401 administration in two DIPG immunocompent models was safe and without toxicity. DNX-2401 prolonged the overall survival, leading 20% to 80% of long-term survivors. Histologic examination showed that DNX-2401 stimulated T-cell infiltration (CD3+, CD4+ and CD8+; p

Diffuse intrinsic pontine glioma (DIPG) is a fatal childhood cancer. We performed a chemical screen in patient-derived DIPG cultures along with RNA-seq analyses and integrated computational modeling to identify potentially effective therapeutic strategies. The multi-histone deacetylase inhibitor panobinostat demonstrated therapeutic efficacy both in vitro and in DIPG orthotopic xenograft models. Combination testing of panobinostat and the histone demethylase inhibitor GSK-J4 revealed that the two had synergistic effects. Together, these data suggest a promising therapeutic strategy for DIPG.

Oncolytic adenoviruses, such as Delta-24-RGD, are replication-competent viruses that are genetically engineered to induce selective cancer cell lysis. In cancer cells, Delta-24-RGD induces massive autophagy, which is required for efficient cell lysis and adenoviral spread. Understanding the cellular mechanisms underlying the regulation of autophagy in cells treated with oncolytic adenoviruses may provide new avenues to improve the therapeutic effect. In this work, we showed that cancer cells infected with Delta-24-RGD undergo autophagy despite the concurrent activation of the AKT/mTOR pathway. Moreover, adenovirus replication induced sustained activation of JNK proteins in vitro. ERK1/1 phosphorylation remained unchanged during adenoviral infection, suggesting specificity of JNK activation. Using genetic ablation and pharmacological inactivation of JNK, we unequivocally demonstrated that cells infected with Delta-24-RGD required JNK activation. Thus, genetic co-ablation of JNK1 and JNK2 genes or inhibition of JNK kinase function rendered Delta-24-RGD–treated cells resistant to autophagy. Accordingly, JNK activation induced phosphorylation of Bcl-2 and prevented the formation of Bcl-2/Beclin 1 autophagy suppressor complexes. Using an orthotopic model of human glioma xenograft, we showed that treatment with Delta-24-RGD induced phosphorylation and nuclear translocation of JNK, as well as phosphorylation of Bcl-2. Collectively, our data identified JNK proteins as an essential mechanistic link between Delta-24-RGD infection and autophagy in cancer cells. Activation of JNK without inactivation of the AKT/mTOR pathway constitutes a distinct molecular signature of autophagy regulation that differentiates Delta-24-RGD adenovirus from the mechanism used by other oncolytic viruses to induce autophagy and provides a new rationale for the combination of oncolytic viruses and chemotherapy.

Diffuse intrinsic pontine gliomas (DIPGs) are aggressive pediatric tumors. Despite advances in targeted treatments radiotherapy remains as the standard treatment being just palliative. The lack of effective therapies represents a critical unmet need for many pediatric solid tumors. Cancer immunotherapy is an ideal alternative choice since the immune response is highly specific; it would persist along time creating memory and will get rid of infiltrative cells even if they are far away. 4-1BB is a major costimulatory receptor promoting the survival and expansion of activated T cells. Aptamers are high-affinity single-stranded nucleic acid ligands that exhibit remarkable affinity and specificity to their targets, comparable or exceeding that of antibodies. TIM-3 is a negative regulator of lymphocyte function that is involved in T-cell exhaustion. In this work we examined the anti-tumor effect of radiotherapy in combination with an agonist 4-1BB antibody and an aptamer against TIM-3. Of importance neither of the treatments resulted in fatal toxicities. Moreover, Combination treatment of 4-1BB with radiotherapy resulted in a significant improvement in survival in mice bearing DIPG orthotopic tumors when compared with single treatment. In addition, this combination led to long-term survivors (90 days). Currently we are performing rechallenge experiments in these animals. Further combination of radiotherapy, with the 4-1BB antibody and the TIM-3 aptamer, that released the immune suppression, is currently under study. At this point the combination between the three approaches showed lack of toxicity. Survival studies are on-going. Mechanistic studies performed on day 16 showed an increase in CD8 effector cells, a decrease in T-regulators Foxp3+ cells and an increase in INF-gamma expression suggesting the triggering of an antitumor-immune response. These results suggest that immuno-therapies approaches in combination with radiotherapy would be worth to explore in the treatment of deadly DIPGs.

Glioblastomas (GBM) are highly malignant brain tumors with a poor prognosis despite intensive research and clinical effort. Circulating biomarkers for the disease would be desirable in order to allow for non-invasive tumor detection and follow-up. Recent findings show that GBM cells release microvesicles that contain a select subset of cellular proteins and RNA. Previously, we observed that exosomes isolated from serum of GBM patients had an increased expression of RNU6 (a small non-coding RNA) compared to control samples, and hence could serve as a non-invasive diagnostic biomarker for GBM. In this study, we set to investigate whether this small non-coding RNA could serve as a differential diagnostic biomarker to distinguish GBM from other brain lesions resembling GBM in neuroimaging. We analyzed the expression of RNU6 in circulating exosomes of patients with six types of brain lesions that can mimic GBM on magnetic resonance imaging (i.e. subacute stroke, acute-subacute haemorrhage, acute demyelinating lesions, abscesses, brain metastases and primary CNS lymphomas). First, we isolated the exosomes from the serum of a subset of patients (20–30 patients) with these pathological conditions using an adsorption method (Exoquick). The same was done in a similar group of healthy controls and GBM patients. Then RNU6 levels were analyzed by digital droplet PCR (ddPCR). Corroborating our previous results, we found that the expression of RNU6 was significantly higher in GBM patients than in healthy controls. In addition, RNU6 levels were significantly higher in exosomes from GBM patients than in exosomes from patients with stroke, haemorrhage or acute multiple sclerosis lesions. We are currently analyzing the data regarding the expression of RNU6 in CNS metastasis and lymphomas. Our preliminary data suggest that RNU6 could serve as a differential diagnostic biomarker for GBM patients.

Glioblastoma is the most common malignant primary brain tumors in adults, and despite established therapeutic approaches, the prognosis remains bleak. Glioblastoma tumors are composed of heterogeneous cell populations, among which the glioma stem-like cells (GSCs) are crucial to tumor self-renewal, growth, and recurrence. The transcription factor sex determining region Y-box 2 (SOX2) is enriched in GSCs where it controls stemness, invasion, and maintenance of tumorigenicity. Therefore, defining the molecular mechanisms governed by SOX2 in GSCs is critical to developing targeted therapies against this recalcitrant population. In this study, we performed a genome-wide analysis of SOX2-regulated coding and non-coding transcripts in GSCs. We identified 2,048 differentially expressed coding transcripts regulated by SOX2. These genes are involved in diverse biological processes, such as cell adhesion, intercellular signal transduction, canonical intracellular signaling cascades (KITLG, GHR, IRS1, HES5, HEY1), and amino-acid metabolism. Additionally, SOX2 was found to differentially regulate 261 non-coding transcripts in GSCs, including miRNAs and lncRNAs. Of particular interest, we identified miR-425-5p as a robust and significant validated candidate for further study. The expression of miR-425-5p was significantly overexpressed in glioblastoma tissue and correlate with SOX2 expression (R2= 0.70; p= 0.01). Using chromatin immunoprecipitation assay followed by qRT-PCR we found that SOX2 activated miR-425-5p expression by directly binding to its promoter. Conversely, inhibition of miR-425-5p expression, using a miRNA sponge lentiviral vector, prevented neurosphere formation, cell proliferation, and promotes apoptosis. Impairing miR-425-5p expression in vivo leads to a significant increase in overall median survival time of nude mice harboring orthotopic glioma xenografts. In summary, this research is the first to identify transcriptional programs controlled by SOX2 in GSCs. In doing so, we defined miR-425-5p as a novel potential onco-miR in GSCs. Taken together, our studies have provided new insights regarding the molecular circuitries governing glioblastoma biology.

Background Prognosis of patients with glioblastoma multiforme (GBM) remains dismal, with median overall survival (OS) of about 15 months. It is therefore crucial to search alternative strategies that improve these results obtained with conventional treatments. In this context, immunotherapy seems to be a promising therapeutic option. We hypothesized that the addition of tumor lysate-pulsed autologous dendritic cells (DCs) vaccination to maximal safe resection followed by radiotherapy and concomitant and adjuvant temozolomide could improve patients’ survival. Methods We conducted a phase-II clinical trial of autologous DCs vaccination in patients with newly diagnosed patients GBM who were candidates to complete or near complete resection. Candidates were finally included if residual tumor volume was lower than 1 cc on postoperative radiological examination. Autologous DCs were generated from peripheral blood monocytes and pulsed with autologous whole tumor lysate. The vaccination calendar started before radiotherapy and was continued during adjuvant chemotherapy. Progression free survival (PFS) and OS were analyzed with the Kaplan–Meier method. Immune response were assessed in blood samples obtained before each vaccines. Results Thirty-two consecutive patients were screened, one of which was a screening failure due to insufficient resection. Median age was 61 years (range 42–70). Karnofsky performance score (KPS) was 90–100 in 29%, 80 in 35.5% and 60–70 in 35.5% of cases. MGMT (O6-methylguanine-DNA-methyltransferase) promoter was methylated in 45.2% of patients. No severe adverse effects related to immunotherapy were registered. Median PFS was 12.7 months (CI 95% 7–16) and median OS was 23.4 months (95% CI 16–33.1). Increase in post-vaccination tumor specific immune response after vaccines (proliferation or cytokine production) was detected in 11/27 evaluated patients. No correlation between immune response and survival was found. Conclusions Our results suggest that the addition of tumor lysate-pulsed autologous DCs vaccination to tumor resection and combined radio-chemotherapy is feasible and safe. A multicenter randomized clinical trial is warranted to evaluate the potential survival benefit of this therapeutic approach. Trial registration This phase-II trial was registered as EudraCT: 2009-009879-35 and ClinicalTrials.gov Identifier: NCT01006044 retrospectively registered

Objective In this work we set to develop and to validate a new in vivo frameless orthotopic Diffuse Intrinsic Pontine Glioma (DIPG) model based in the implantation of a guide-screw system. Methods It consisted of a guide-screw also called bolt, a Hamilton syringe with a 26-gauge needle and an insulin-like 15-gauge needle. The guide screw is 2.6 mm in length and harbors a 0.5 mm central hole which accepts the needle of the Hamilton syringe avoiding a theoretical displacement during insertion. The guide-screw is fixed on the mouse skull according to the coordinates: 1mm right to and 0.8 mm posterior to lambda. To reach the pons the Hamilton syringe is adjusted to a 6.5 mm depth using a cuff that serves as a stopper. This system allows delivering not only cells but also any kind of intratumoral chemotherapy, antibodies or gene/viral therapies. Results The guide-screw was successfully implanted in 10 immunodeficient mice and the animals were inoculated with DIPG human cell lines during the same anesthetic period. All the mice developed severe neurologic symptoms and had a median overall survival of 95 days ranging the time of death from 81 to 116 days. Histopathological analysis confirmed tumor into the pons in all animals confirming the validity of this model. Conclusion Here we presented a reproducible and frameless DIPG model that allows for rapid evaluation of tumorigenicity and efficacy of chemotherapeutic or gene therapy products delivered intratumorally to the pons.

// Noemi Garcia-Romero 1, 2, * , Josefa Carrion-Navarro 1, 3, * , Susana Esteban-Rubio 1, 3, * , Elisa Lazaro-Ibanez 4 , Maria Peris-Celda 5 , Marta M. Alonso 6 , Juan Guzman-De-Villoria 7 , Carlos Fernandez-Carballal 8 , Ana Ortiz de Mendivil 1 , Sara Garcia-Duque 1 , Carmen Escobedo-Lucea 4 , Ricardo Prat-Acin 9 , Cristobal Belda-Iniesta 1, 3 , Angel Ayuso-Sacido 1, 2, 3 1 Fundacion de Investigacion HM Hospitales, HM Hospitales, Madrid, Spain 2 IMDEA Nanoscience, Madrid, Spain 3 Facultad de Medicina (IMMA), Universidad San Pablo-CEU, Madrid, Spain 4 Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland 5 Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA 6 Clinica Universidad de Navarra, CIMA, Pamplona, Spain 7 Servicio de Radiodiagnostico, Hospital General Universitario Gregorio Maranon, Madrid, Spain 8 Servicio de Neurocirugia, Hospital General Universitario Gregorio Maranon, Madrid, Spain 9 Departamento de Neurocirugia, Hospital Universitario la Fe, Valencia, Spain * These authors have contributed equally to this work Correspondence to: Angel Ayuso-Sacido, email: ayusosacido@gmail.com Keywords: extracellular vesicles, brain tumors, blood-brain barrier, biomarkers Received: September 20, 2016 Accepted: November 07, 2016 Published: November 26, 2016 ABSTRACT Tumor-cell-secreted extracellular vesicles (EVs) can cross the disrupted blood-brain barrier (BBB) into the bloodstream. However, in certain gliomas, the BBB remains intact, which might limit EVs release. To evaluate the ability of tumor-derived EVs to cross the BBB, we used an orthotopic xenotransplant mouse model of human glioma-cancer stem cells featuring an intact BBB. We demonstrated that all types of tumor cells-derived EVs−apoptotic bodies, shedding microvesicles and exosomes−cross the intact BBB and can be detected in the peripheral blood, which provides a minimally invasive method for their detection compared to liquid biopsies obtained from cerebrospinal fluid (CSF). Furthermore, these EVs can be readily distinguished from total murine EVs, since they carry human-specific DNA sequences relevant for GBM biology. In a small cohort of glioma patients, we finally demonstrated that peripheral blood EVs cargo can be successfully used to detect the presence of IDH1 G395A , an essential biomarker in the current management of human glioma

Osteosarcoma is the most common malignant bone tumor in children and adolescents. The presence of metastases and the lack of response to conventional treatment are the major adverse prognostic factors. Therefore, there is an urgent need for new treatment strategies that overcome both of these problems. Our purpose was to elucidate whether the use of the oncolytic adenovirus Δ24-RGD alone or in combination with standard chemotherapy would be effective, in vitro and in vivo, against osteosarcoma. Our results showed that Δ24-RGD exerted a potent antitumor effect against osteosarcoma cell lines that was increased by the addition of cisplatin. Δ24-RGD osteosarcoma treatment resulted in autophagy in vitro that was further enhanced when combined with cisplatin. Of importance, administration of Δ24-RGD and/or cisplatin, in novel orthotopic and two lung metastatic models in vivo resulted in a significant reduction of tumor burden meanwhile maintaining a safe toxicity profile. Together, our data underscore the potential of Δ24-RGD to become a realistic therapeutic option for primary and metastatic pediatric osteosarcoma. Moreover, this study warrants a future clinical trial to evaluate the safety and efficacy of Δ24-RGD for this devastating disease.

// Konrad Gabrusiewicz 1,* , Dan Liu 1,* , Nahir Cortes-Santiago 1,* , Mohammad B. Hossain 1 , Charles A. Conrad 1 , Kenneth D. Aldape 2 , Gregory N. Fuller 2 , Frank C. Marini 3 , Marta M. Alonso 4 , Miguel Angel Idoate 5 , Mark R. Gilbert 1 , Juan Fueyo 1 , and Candelaria Gomez-Manzano 1,6 1 Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA 2 Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA 3 Institute of Regenerative Medicine, Wake Forest University, Winston-Salem, North Carolina, USA 4 Department of Medical Oncology, University Hospital of Navarra, Pamplona, Spain 5 Department of Pathology, University Hospital of Navarra, Pamplona, Spain 6 Department of Genetics, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA * contributed equally to the work Correspondence: Candelaria Gomez-Manzano, email: // Keywords : Brain tumors, antiangiogenesis, Tie2, tumor microenvironment, monocyte Received : January 6, 2014 Accepted : April 11, 2014 Published : April 11, 2014 Abstract The addition of anti-angiogenic therapy to the few treatments available to patients with malignant gliomas was based on the fact that these tumors are highly vascularized and on encouraging results from preclinical and clinical studies. However, tumors that initially respond to this therapy invariably recur with the acquisition of a highly aggressive and invasive phenotype. Although several myeloid populations have been associated to this pattern of recurrence, a specific targetable population has not been yet identified. Here, we present evidence for the accumulation of Tie2-expressing monocytes/macrophages (TEMs) at the tumor/normal brain interface of mice treated with anti-VEGF therapies in regions with heightened tumoral invasion. Furthermore, we describe the presence of TEMs in malignant glioma surgical specimens that recurred after bevacizumab treatment. Our studies showed that TEMs enhanced the invasive properties of glioma cells and secreted high levels of gelatinase enzymatic proteins. Accordingly, Tie2 + MMP9 + monocytic cells were consistently detected in the invasive tumor edge upon anti-VEGF therapies. Our results suggest the presence of a specific myeloid/monocytic subpopulation that plays a pivotal role in the mechanism of escape of malignant gliomas from anti-VEGF therapies and therefore constitutes a new cellular target for combination therapies in patients selected for anti-angiogenesis treatment.

Background. Glioblastoma multiforme (GBM) is the most frequent malignant brain tumor in adults, and its prognosis remains dismal despite intensive research and therapeutic advances. Diagnostic biomarkers would be clinically meaningful to allow for early detection of the tumor and for those cases in which surgery is contraindicated or biopsy results are inconclusive. Recent findings show that GBM cells release microvesicles that contain a select subset of cellular proteins and RNA. The aim of this hypothesis-generating study was to assess the diagnostic potential of miRNAs found in microvesicles isolated from the serum of GBM patients. Methods. To control disease heterogeneity, we used patients with newly diagnosed GBM. In the discovery stage, PCR-based TaqMan Low Density Arrays followed by individual quantitative reverse transcriptase polymerase chain reaction were used to test the differences in the miRNA expression levels of serum microvesicles among 25 GBM patients and healthy controls paired by age and sex. The detected noncoding RNAs were then validated in another 50 GBM patients. Results. We found that the expression levels of 1 small noncoding RNA (RNU6-1) and 2 microRNAs (miR-320 and miR-574-3p) were significantly associated with a GBM diagnosis. In addition, RNU6-1 was consistently an independent predictor of a GBM diagnosis. Conclusions. Altogether our results uncovered a small noncoding RNA signature in microvesicles isolated from GBM patient serum that could be used as a fast and reliable differential diagnostic biomarker.

Susceptibility to pneumococcal infections in Sj?gren syndrome (SS)―an autoimmune inflammatory disease―patients is not well known, although these patients frequently develop respiratory diseases. The relative risk of developing pneumococcal disease in SS patients versus diabetes mellitus type 2 (DM-2) patients, matched by age, gender, and length of enrolment was studied. From January 1998 to September 2013 the records of Donostia University Hospital were analyzed, which among other patient’s data includes: number and type of hospital admissions and number and type of laboratory determinations. Streptococcus pneumoniae isolates of the same serotype causing recurrent infections were characterized by PFGE. The study comprised 127 patients in the SS group (69 primary and 58 secondary) and 127 in the DM-2 group as control. In 12 SS patients, (9.4%) 22 pneumococcal disease episodes were detected. Two patients (1.6%) with a single episode each one were observed among DM-2 patients, p = 0.01, RR for SS patients 6 (95% CI 1.4 to 26.3). No differences could be demonstrated between the two groups of patients in infections caused by Staphylococcus aureus or Streptococcus agalactiae. Most pneumococcal serotypes in SS patients belonged to the 13-valent (50%) and 23-valent (75%) anti-pneumococcal vaccine. SS patients are associated with and increased risk of suffering from pneumococcal disease. Vaccination should be considered in this group of patients.

Sodium dichloroacetate (DCA) is an investigational medicinal product which has a potential anticancer preparation as a metabolic regulator in cancer cells’ mitochondria. Inhibition of pyruvate dehydrogenase kinases by DCA keeps the pyruvate dehydrogenase complex in the active form, resulting in decreased lactic acid in the tumor microenvironment. This literature review displays the preclinical research data on DCA’s effects on the cell pyruvate dehydrogenase deficiency, pyruvate mitochondrial oxidative phosphorylation, reactive oxygen species generation, and the Na+−K+−2Cl− cotransporter expression regulation in relation to gender. It presents DCA pharmacokinetics and the hepatocarcinogenic effect, and the safety data covers the DCA monotherapy efficacy for various human cancer xenografts in vivo in male and female animals. Preclinical cancer researchers report the synergistic effects of DCA combined with different drugs on cancer by reversing resistance to chemotherapy and promoting cell apoptosis. Researchers note that female and male animals differ in the mechanisms of cancerogenesis but often ignore studying DCA’s effects in relation to gender. Preclinical gender-related differences in DCA pharmacology, pharmacological mechanisms, and the elucidation of treatment efficacy in gonad hormone dependency could be relevant for individualized therapy approaches so that gender-related differences in treatment response and safety can be proposed.

BACKGROUND Diffuse intrinsic pontine glioma (DIPG) is an aggressive brain tumor, being the leading cause of pediatric death caused by cancer. We previously showed that administration of the oncolytic virus Delta-24-RGD to DIPG murine models was safe and led to an increase in the median survival of these animals. However, not all the animals responded, underscoring the need to improve this therapy. In order to increase the antitumoral effect of the virus, we have engineered Delta-24-RGD with the costimulatory ligand 4-1BBL (Delta24-ACT). 4-1BB is a costimulatory receptor that promotes the survival and expansion of activated T cells, and the generation and maintenance of memory CD8+ T cells. In this project, we evaluated the oncolytic effect of Delta24-ACT and the antitumor immune response in DIPG murine models. MATERIALS AND METHODS We use the NP53 and XFM murine DIPG cell lines. Flow cytometry was used to assess cell infectivity and ligand expression. We analyzed viral replication using a method based in hexon detection, and viral cytotoxic effect using the MTS assay. For immunogenic cell death analysis, we measured ATP secretion by a luminometric assay and calreticulin location by flow cytometry and immunofluorescence. For in vivo studies, cells and virus were injected in the pons of the mice, using the screw-guided system. RESULTS In vitro, Delta24-ACT was able to infect and induce cell death in a dose-dependent manner in murine DIPG cell lines. In addition, Delta24-ACT was able to replicate in these tumor cells and to express viral proteins. Moreover, infected cells expressed 41BBL in their membranes. Delta24-ACT could induce immunogenic cell death due to an increased secretion of ATP and calreticulin translocation to the membrane of infected cells (in no-infected cells it located in the ER), DAMPs that can trigger the immune response activation. In vivo, Delta24-ACT demonstrated to be safe in all the tested doses and was able to induce a significant increase in the median survival of the treated animals. Moreover, long-term survivors display immunological memory. CONCLUSIONS Delta24-ACT treatment led to antitumoral effect in DIPG murine cell lines in vitro. Of significance, we have demonstrated that in vivo administration of Delta24-ACT is safe and results in an enhanced antitumor effect. Future in vivo studies will explore the underlying immune mechanism of the virus.

BACKGROUND Atypical teratoid/rhabdoid tumors (AT/RTs) are rare pediatric brain tumors affecting mainly infants and young children. However, AT/RTs encompass almost 10% of death caused by pediatric brain tumors, and the 2-year overall survival for these children remains below 20%. For this reason, AT/RT ranks among the deadliest pediatric brain tumors. Therefore, it is clear we need to find out new therapeutic options for these children. Delta-24-RGD is an oncolytic adenovirus that has already demonstrated its efficacy as in Phase I/II clinical trials in adult patients affected by high grade gliomas with no evidence of severe side effects. Of interest for pediatric brain tumors, the safety of Delta-24-RGD is has also been demonstrated in an ongoing Phase I clinical trial for the treatment of DIPGs (NCT03178032). For these reasons, we propose to evaluate the anti-tumor effect of Delta-24-RGD in preclinical models of ATRT. MATERIAL AND METHODS Our studies have been carried out in three stablished AT/RT cell lines (BT-12, CHLA-06 and CHLA-266). In vitro, AT/RT cultures were infected with Delta-24-RGD-GFP to confirm the infectivity of the virus by flow cytometry. Replication of Delta-24-RGD was ensured by titrating the PFUs generated in AT/RT infected cultures. In regard to cytolytic effect, viability assays (MTS) were conducted in AT/RT cultures infected at increasing MOIs of Delta-24-RGD. In vivo, AT/RT cell lines were engrafted in Rag-2 mice in supratentorial and infratentorial locations, and the animals were treated with Delta-24-RGD at 107 or 108 PFU/animal (intra-tumor administration), or PBS. The therapeutic benefit of Delta-24-RGD was evaluated comparing the overall survival obtained for treated and untreated animals using the Log-rank test. We have also generated models of disseminated disease through intraventricular injection of the tumor cells, thus mimicking the lesions found in patients. AT/RT cell lines were transduced with a luc-expressing lentivirus to facilitate the follow up of these tumors. Mice bearing disseminated AT/RT were treated with Delta-24-RGD at 107 or 108 PFU/animal, or PBS (control). The therapeutic effect was monitored by bioluminescence and by comparison of the survival curves (Log-rank). RESULTS The virus was able to infect and replicate in tumor three different cell culture models of AT/RT, inducing a potent cytotoxic effect that resulting in IC50 values below 1 PFU/cell. Administration of the virus in mice bearing localized AT/RT (supratentorial and infratentorial) extended significantly the survival the animals, leading to up to 20% of long-term survivors. In disseminated AT/RT models, light emission reveals reduction of tumor growth in virus treated animals, resulting in an increased overall survival. CONCLUSION In conclusion, these results demonstrate that Delta-24-RGD could be a feasible therapeutic choice for patients affected by AT/RT.

Pediatric High Grade Glioma (pHGG), including Diffuse Intrinsic Pontine Glioma (DIPG) are the most common and aggressive pediatric brain tumor. Despite great strides in the knowledge of their genetic make-up and new therapies, the outcome for children affected with these malignancies remains dismal. Therefore, it is critical to implement new therapeutic approaches that improve the survival and quality of life of these kids. Delta-24-RGD (DNX-2401 in the clinic), is a tumor specific oncolytic adenovirus that has been tested in preclinical and clinical studies in adult high grade glioma, demonstrating its safe profile and certain degree of efficacy. The objective of this work was to evaluate the safety and the antitumor effect of DNX-2401 in pHGG and DIPGs. Delta-24-RGD showed a potent antitumor effect in a battery of pHGG (N=5) and DIPGs (N=6) cell lines (IC50 ranging from 1 to 50 MOIs) that was mediated by an effective replication. Moreover, Delta-24-RGD administration to mice bearing pHGG and DIPG tumors resulted in a significantly increase in the overall survival, and in some cases leading to 50% of long-term survivors. Clinical trials with DNX-2401 have shown that the immune response triggered in a subset of glioma patients is the responsible for the durable responses observed. Therefore, we assessed viral efficacy in two immunocompetent models bearing mice DIPG tumors. Delta-24-RGD, administered in mice brainstem, was well tolerated and no signs of toxicity were observed. Importantly, Delta-24-RGD treatment resulted in a significant survival benefit in immunocompent DIPG orthotopic models. Tumor examination showed that Delta-24-RGD also promoted an increase in T-cell infiltration (CD3+, CD4+ and CD8+; p Citation Format: Naiara Martinez-Velez, Marc Garcia-Moure, Virginia Laspidea, Maider Varela, Oren Becher, Candelaria Gomez-Manzano, Juan Fueyo, Ana Patiño, Ricardo Diez-Valle, Sonia Tejada-Solis, Marta M. Alonso. Delta-24-RGD/DNX-2401: Oncolytic virotherapy for pediatric high grade glioma and DIPG [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3117.

Diffuse intrinsic pontine glioma (DIPG) is an aggressive and incurable pediatric brain tumor that arises in the brainstem. The median overall survival is only one year being the standard of treatment radiotherapy. Oncolytic adenoviruses have emerged as a promising therapeutic option for DIPG due to their specificity to tumor cells. Our clinical experience has shown that stimulation of an immune response against the tumor by the adenovirus is important for the effectivity of this therapy. 4-1BB is a major costimulatory receptor promoting the survival and expansion of activated T cells, as well as the generation and maintenance of memory CD8+ T cells. Since CD8+ T cells play a pivotal role in tumor immunity, enhancing 4-1BB costimulation promotes the generation of antitumor immune responses. In order to improve the antitumor immune response induced by the adenovirus, we have engineered the costimulatory molecule 4-1BBL into the genome of Delta-24-RGD (Delta-24-ACT). Delta-24-ACT was able to infect and to express viral proteins in a dose-dependent manner in murine DIPG cell lines, NP53 and XFM in vitro and in vivo. Importantly, Delta-24-ACT exerts a significant antitumoral effect in vitro, being XFM the cell line with higher sensitivity to the virus (3 days-IC(50): 3.4 MOI). DIPGcells infected with Delta-24-ACT during 24 hours showed expression of 4-1BBL in the plasma membrane in around 50% of cells. Delta-24-ACT induced immunogenic cell death in DIPG cell lines showing a significant increase of calreticulin in the plasma membrane, the release of ATP and HMGB1, which are DAMPs able to trigger an adaptive immune response. All these results suggest that Delta-24-ACT is functional in DIPG models in vitro. We are currently, performing toxicity and efficacy in vivo experiments in orthotopic DIPG models. Further, in vivo studies will uncover of the suitability of this new virus for the treatment of DIPG.