Has the survival of patients with glioblastoma changed over the years?

Modeling Glioma Intratumoral Heterogeneity with Primary Human Neural Stem and Progenitor Cells

Glioblastoma multiforme (GBM) is a deadly form of glioma notable for its significant intratumoral heterogeneity, which is believed to drive therapy resistance. GBM has been observed to mimic a neural stem cell hierarchy reminiscent of normal brain development. However, it is still unclear how cell-of-origin shapes intratumoral heterogeneity. Here, we develop a model of glioma initiation using neural stem and progenitor cells (NSPCs) purified from fetal human brain tissue. We previously described a method to prospectively isolate and culture tripotent neural stem cells (NSCs), bipotent glial progenitor cells (GPCs), and unipotent oligodendrocyte precursor cells (OPCs). We transduced these isogenic lines with dominant-negative TP53R175H and NF1 knockdown, a commonly-used genetic model of GBM in mice. These reprogrammed lines robustly engrafted when transplanted into the brains of immunodeficient mice, and showed significant expansion over time. Engrafted cells were reextracted from the mouse brain for single cell RNA sequencing (scRNA-seq), in order to quantify how the cell-of-origin modulates the cellular subtypes found in the resulting tumor. This result revealed the strong influence the cell-of-origin plays in glioma heterogeneity. Our platform is highly adaptable and allows for modular and systematic interrogation of how cell-of-origin shape the tumor landscape.

Metabolic reprogramming of poly(morpho)nuclear giant cells determines glioblastoma recovery from doxorubicin-induced stress

BACKGROUND

Multi-drug resistance of poly(morpho)nuclear giant cells (PGCs) determines their cytoprotective and generative potential in cancer ecosystems. However, mechanisms underlying the involvement of PGCs in glioblastoma multiforme (GBM) adaptation to chemotherapeutic regimes remain largely obscure. In particular, metabolic reprogramming of PGCs has not yet been considered in terms of GBM recovery from doxorubicin (DOX)-induced stress.

METHODS

Long-term proteomic and metabolic cell profiling was applied to trace the phenotypic dynamics of GBM populations subjected to pulse DOX treatment in vitro, with a particular focus on PGC formation and its metabolic background. The links between metabolic reprogramming, drug resistance and drug retention capacity of PGCs were assessed, along with their significance for GBM recovery from DOX-induced stress.

RESULTS

Pulse DOX treatment triggered the transient formation of PGCs, followed by the appearance of small expanding cell (SEC) clusters. Development of PGCs was accompanied by the mobilization of their metabolic proteome, transient induction of oxidative phosphorylation (OXPHOS), and differential intracellular accumulation of NADH, NADPH, and ATP. The metabolic background of PGC formation was confirmed by the attenuation of GBM recovery from DOX-induced stress following the chemical inhibition of GSK-3β, OXPHOS, and the pentose phosphate pathway. Concurrently, the mobilization of reactive oxygen species (ROS) scavenging systems and fine-tuning of NADPH-dependent ROS production systems in PGCs was observed. These processes were accompanied by perinuclear mobilization of ABCB1 and ABCG2 transporters and DOX retention in the perinuclear PGC compartments.

CONCLUSIONS

These data demonstrate the cooperative pattern of GBM recovery from DOX-induced stress and the crucial role of metabolic reprogramming of PGCs in this process. Metabolic reprogramming enhances the efficiency of self-defense systems and increases the DOX retention capacity of PGCs, potentially reducing DOX bioavailability in the proximity of SECs. Consequently, the modulation of PGC metabolism is highlighted as a potential target for intervention in glioblastoma treatment.

Fatty Acid Amides Suppress Proliferation via Cannabinoid Receptors and Promote the Apoptosis of C6 Glioma Cells in Association with Akt Signaling Pathway Inhibition

A glioma is a type of tumor that acts on the Central Nervous System (CNS) in a highly aggressive manner. Gliomas can occasionally be inaccurately diagnosed and treatments have low efficacy, meaning that patients exhibit a survival of less than one year after diagnosis. Due to factors such as intratumoral cell variability, inefficient chemotherapy drugs, adaptive resistance development to drugs and tumor recurrence after resection, the search continues for new drugs that can inhibit glioma cell growth. As such, analogues of endocannabinoids, such as fatty acid amides (FAAs), represent interesting alternatives for inhibiting tumor growth, since FAAs can modulate several metabolic pathways linked to cancer and, thus, may hold potential for managing glioblastoma. The aim of this study was to investigate the in vitro effects of two fatty ethanolamides (FAA1 and FAA2), synthetized via direct amidation from andiroba oil (Carapa guianensis Aublet), on C6 glioma cells. FAA1 and FAA2 reduced C6 cell viability, proliferation and migratory potential in a dose-dependent manner and were not toxic to normal retina glial cells. Both FAAs caused apoptotic cell death through the loss of mitochondrial integrity (ΔΨm), probably by activating cannabinoid receptors, and inhibiting the PI3K/Akt pathway. In conclusion, FAAs derived from natural products may have the potential to treat glioma-type brain cancer.

BCL6 is a context-dependent mediator of the glioblastoma response to irradiation therapy

Glioblastoma is a rapidly fatal brain cancer that does not respond to therapy. Previous research showed that the transcriptional repressor protein BCL6 is upregulated by chemo and radiotherapy in glioblastoma, and inhibition of BCL6 enhances the effectiveness of these therapies. Therefore, BCL6 is a promising target to improve the efficacy of current glioblastoma treatment. BCL6 acts as a transcriptional repressor in germinal centre B cells and as an oncogene in lymphoma and other cancers. However, in glioblastoma, BCL6 induced by therapy may not be able to repress transcription. Using a BCL6 inhibitor, the whole proteome response to irradiation was compared with and without BCL6 activity. Acute high dose irradiation caused BCL6 to switch from repressing the DNA damage response to promoting stress response signalling. Rapid immunoprecipitation mass spectrometry of endogenous proteins (RIME) enabled comparison of BCL6 partner proteins between untreated and irradiated glioblastoma cells. BCL6 was associated with transcriptional coregulators in untreated glioblastoma including the known partner NCOR2. However, this association was lost in response to acute irradiation, where BCL6 unexpectedly associated with synaptic and plasma membrane proteins. These results reveal the activity of BCL6 under therapy-induced stress is context-dependent, and potentially altered by the intensity of that stress.

Unlocking the Potential of Ultra-High Dose Fractionated Radiation for Effective Treatment of Glioblastoma in Mice

Background: Current radiotherapy regimens for glioblastoma (GBM) have limited efficacy and fails to eradicate tumors. Regenerative medicine brings hope for repairing damaged tissue, opening opportunities for elevating the maximum acceptable radiation dose. In this study, we explored the effect of ultra-high dose fractionated radiation on tumor responses and brain injury in immunocompetent mice which can better mimic the tumor-host interactions observed in patients. We also evaluated the role of the hypoxia-inducible factor-1 alpha under radiation as potential target for combating radiation-induced brain injury. Methods: Naïve and Hif-1α+/- heterozygous mice received a fractionated daily dose of 20 Gy for three or five consecutive days. Magnetic resonance imaging (MRI) and histology were performed to assess brain injury post-radiation. The 2×105 human GBM1 luciferase-expressing cells were transplanted with tolerance induction protocol. Fractionated radiotherapy was performed during the exponential phase of tumor growth. Bioluminescence imaging, MRI, and immunohistochemistry staining were performed to evaluate tumor growth dynamics and radiotherapy responses. Additionally, animal lifespan was recorded. Results: Fractionated radiation of 5×20 Gy induced severe brain damage, starting 3 weeks after radiation. All animals from this group died within 12 weeks. In contrast, later onset and less severe brain injury were observed starting 12 weeks after radiation of 3×20 Gy. It resulted in complete GBM eradication and survival of all treated animals. Furthermore, Hif-1α+/- mice exhibited more severe vascular damage after fractionated radiation of 3×20 Gy. Conclusion: Ultra-high dose fractionated 3×20 Gy radiation has the potential to fully eradicate GBM cells at the cost of only mild brain injury. The Hif-1α gene is a promising target for ameliorating vascular impairment post-radiation, encouraging the implementation of neurorestorative strategies.

Prognosis of glioblastoma patients improves significantly over time interrogating historical controls

BACKGROUND

Glioblastoma (GBM) is the most common devastating primary brain cancer in adults. In our clinical practice, median overall survival (mOS) of GBM patients seems increasing over time.

METHODS

To address this observation, we have retrospectively analyzed the prognosis of 722 newly diagnosed GBM patients, aged below 70, in good clinical conditions (i.e. Karnofsky Performance Status -KPS- above 70%) and treated in our department according to the standard of care (SOC) between 2005 and 2018. Patients were divided into two groups according to the year of diagnosis (group 1: from 2005 to 2012; group 2: from 2013 to 2018).

RESULTS

Characteristics of patients and tumors of both groups were very similar regarding confounding factors (age, KPS, MGMT promoter methylation status and treatments). Follow-up time was fixed at 24 months to ensure comparable survival times between both groups. Group 1 patients had a mOS of 19 months ([17.3-21.3]) while mOS of group 2 patients was not reached. The recent period of diagnosis was significantly associated with a longer mOS in univariate analysis (HR=0.64, 95% CI [0.51 - 0.81]), p < 0.001). Multivariate Cox analysis showed that the period of diagnosis remained significantly prognostic after adjustment on confounding factors (adjusted Hazard Ratio (aHR) 0.49, 95% CI [0.36-0.67], p < 0.001).

CONCLUSION

This increase of mOS over time in newly diagnosed GBM patients could be explained by better management of potentially associated non-neurological diseases, optimization of validated SOC, better management of treatments side effects, supportive care and participation in clinical trials.

Value of long non-coding RNA HAS2-AS1 as a diagnostic and prognostic marker of glioma

BACKGROUND

Glioma presents high incidence and poor prognosis, and therefore more effective treatments are needed. Studies have confirmed that long non-coding RNAs (lncRNAs) basically regulate various human diseases including glioma. It has been theorized that HAS2-AS1 serves as an lncRNA to exert an oncogenic role in varying cancers. This study aimed to assess the value of lncRNA HAS2-AS1 as a diagnostic and prognostic marker for glioma.

METHODS

The miRNA expression data and clinical data of glioma were downloaded from the TCGA database for differential analysis and survival analysis. In addition, pathological specimens and specimens of adjacent normal tissue from 80 patients with glioma were used to observe the expression of HAS2-AS1. The receiver operating characteristic (ROC) curve was used to analyze the diagnostic ability and prognostic value of HAS2-AS1 in glioma. Meanwhile, a Kaplan-Meier survival curve was plotted to evaluate the survival of glioma patients with different HAS2-AS1 expression levels.

RESULTS

HAS2-AS1 was significantly upregulated in glioma tissues compared with normal tissue. The survival curves showed that overexpression of HAS2-AS1 was associated with poor overall survival (OS) and progression-free survival (PFS). Several clinicopathological factors of glioma patients, including tumor size and WHO grade, were significantly correlated with HAS2-AS1 expression in tissues. The ROC curve showed an area under the curve (AUC) value of 0.863, indicating that HAS2-AS1 had good diagnostic value. The ROC curve for the predicted OS showed an AUC of 0.906, while the ROC curve for predicted PFS showed an AUC of 0.88. Both suggested that overexpression of HAS2-AS1 was associated with poor prognosis.

CONCLUSIONS

Normal tissues could be clearly distinguished from glioma tissues based on HAS2-AS1 expression. Moreover, overexpression of HAS2-AS1 indicated poor prognosis in glioma patients. Therefore, HAS2-AS1 could be used as a diagnostic and prognostic marker for glioma.

The Prognostic Role of Volumetric MRI Evaluation in the Surgical Treatment of Glioblastoma

Background: Glioblastoma is the most common primary brain neoplasm in adults, with a poor prognosis despite a constant effort to improve patient survival. Some neuroradiological volumetric parameters seem to play a predictive role in overall survival (OS) and progression-free survival (PFS). The aim of this study was to analyze the impact of the volumetric areas of contrast-enhancing tumors and perineoplastic edema on the survival of patients treated for glioblastoma. Methods: A series of 87 patients who underwent surgery was retrospectively analyzed; OS and PFS were considered the end points of the study. For each patient, a multidisciplinary revision was conducted in collaboration with the Neuroradiology and Neuro-Oncology Board. Manual and semiautomatic measurements were adopted to perform the radiological evaluation, and the following quantitative parameters were retrospectively analyzed: contrast enhancement preoperative tumor volume (CE-PTV), contrast enhancement postoperative tumor volume (CE-RTV), edema/infiltration preoperative volume (T2/FLAIR-PV), edema/infiltration postoperative volume (T2/FLAIR-RV), necrosis volume inside the tumor (NV), and total tumor volume including necrosis (TV). Results: The median OS value was 9 months, and the median PFS value was 4 months; the mean values were 12.3 and 6.9 months, respectively. Multivariate analysis showed that the OS-related factors were adjuvant chemoradiotherapy (p < 0.0001), CE-PTV < 15 cm3 (p = 0.03), surgical resection > 95% (p = 0.004), and the presence of a "pseudocapsulated" radiological morphology (p = 0.04). Conclusions: Maximal safe resection is one of the most relevant predictive factors for patient survival. Semiautomatic preoperative MRI evaluation could play a key role in prognostically categorizing these tumors.

Unlocking the potential of ultra-high dose fractionated radiation for effective treatment of glioblastoma

Background

Conventional radiation therapy for glioblastoma (GBM) has limited efficacy. Regenerative medicine brings hope for repairing damaged tissue, opening opportunities for elevating the maximum acceptable radiation dose. In this study, we explored the effect of ultra-high dose fractionated radiation on brain injury and tumor responses in immunocompetent mice. We also evaluated the role of the HIF-1α under radiation.

Methods

Naïve and hypoxia-inducible factor-1 alpha (HIF-1α)+/- heterozygous mice received a fractionated daily dose of 20 Gy for three or five consecutive days. Magnetic resonance imaging (MRI) and histology were performed to assess brain injury post-radiation. The 2×105 human GBM1 luciferase-expressing cells were transplanted with tolerance induction protocol. Fractionated radiotherapy was performed during the exponential phase of tumor growth. BLI, MRI, and immunohistochemistry staining were performed to evaluate tumor growth dynamics and radiotherapy responses. Additionally, animal lifespan was recorded.

Results

Fractionated radiation of 5×20 Gy induced severe brain damage, starting 3 weeks after radiation. All animals from this group died within 12 weeks. In contrast, later onset and less severe brain injury were observed starting 12 weeks after radiation of 3×20 Gy. It resulted in complete GBM eradication and survival of all treated animals. Furthermore, HIF-1α+/- mice exhibited more obvious vascular damage 63 weeks after fractionated radiation of 3×20 Gy.

Conclusion

Ultra-high dose fractionated 3×20 Gy radiation can eradicate the GBM cells at the cost of only mild brain injury. The HIF-1α gene is a promising target for ameliorating vascular impairment post-radiation, encouraging the implementation of neurorestorative strategies.

Anti-PD-1 and Extended Half-life IL2 Synergize for Treatment of Murine Glioblastoma Independent of Host MHC Class I Expression

Glioblastoma (GBM) is the most common malignant brain tumor in adults, responsible for approximately 225,000 deaths per year. Despite preclinical successes, most interventions have failed to extend patient survival by more than a few months. Treatment with anti-programmed cell death protein 1 (anti-PD-1) immune checkpoint blockade (ICB) monotherapy has been beneficial for malignant tumors such as melanoma and lung cancers but has yet to be effectively employed in GBM. This study aimed to determine whether supplementing anti-PD-1 ICB with engineered extended half-life IL2, a potent lymphoproliferative cytokine, could improve outcomes. This combination therapy, subsequently referred to as enhanced checkpoint blockade (ECB), delivered intraperitoneally, reliably cures approximately 50% of C57BL/6 mice bearing orthotopic GL261 gliomas and extends median survival of the treated cohort. In the CT2A model, characterized as being resistant to CBI, ECB caused a decrease in CT2A tumor volume in half of measured animals similar to what was observed in GL261-bearing mice, promoting a trending survival increase. ECB generates robust immunologic responses, features of which include secondary lymphoid organ enlargement and increased activation status of both CD4 and CD8 T cells. This immunity is durable, with long-term ECB survivors able to resist GL261 rechallenge. Through employment of depletion strategies, ECB's efficacy was shown to be independent of host MHC class I-restricted antigen presentation but reliant on CD4 T cells. These results demonstrate ECB is efficacious against the GL261 glioma model through an MHC class I-independent mechanism and supporting further investigation into IL2-supplemented ICB therapies for tumors of the central nervous system.

Melatonin in Combination with Albendazole or Albendazole Sulfoxide Produces a Synergistic Cytotoxicity against Malignant Glioma Cells through Autophagy and Apoptosis

Glioblastoma is the most aggressive and lethal brain tumor in adults, presenting diffuse brain infiltration, necrosis, and drug resistance. Although new drugs have been approved for recurrent patients, the median survival rate is two years; therefore, new alternatives to treat these patients are required. Previous studies have reported the anticancer activity of albendazole, its active metabolite albendazole sulfoxide, and melatonin; therefore, the present study was performed to evaluate if the combination of melatonin with albendazole or with albendazole sulfoxide induces an additive or synergistic cytotoxic effect on C6 and RG2 rat glioma cells, as well as on U87 human glioblastoma cells. Drug interaction was determined by the Chou-Talalay method. We evaluated the mechanism of cell death by flow cytometry, immunofluorescence, and crystal violet staining. The cytotoxicity of the combinations was mainly synergistic. The combined treatments induced significantly more apoptotic and autophagic cell death on the glioma cell lines. Additionally, albendazole and albendazole sulfoxide inhibited proliferation independently of melatonin. Our data justify continuing with the evaluation of this proposal since the combinations could be a potential strategy to aid in the treatment of glioblastoma.

Refining the Intraoperative Identification of Suspected High-Grade Glioma Using a Surgical Fluorescence Biomarker: GALA BIDD Study Report

Background. Improving intraoperative accuracy with a validated surgical biomarker is important because identifying high-grade areas within a glioma will aid neurosurgical decision-making and sampling. Methods. We designed a multicentre, prospective surgical cohort study (GALA-BIDD) to validate the presence of visible fluorescence as a pragmatic intraoperative surgical biomarker of suspected high-grade disease within a tumour mass in patients undergoing 5-aminolevulinic acid (5-ALA) fluorescence-guided cytoreductive surgery. Results. A total of 106 patients with a suspected high-grade glioma or malignant transformation of a low-grade glioma were enrolled. Among the 99 patients who received 5-ALA, 89 patients were eligible to assess the correlation of fluorescence with diagnosis as per protocol. Of these 89, 81 patients had visible fluorescence at surgery, and 8 patients had no fluorescence. A total of 80 out of 81 fluorescent patients were diagnosed as high-grade gliomas on postoperative central review with 1 low-grade glioma case. Among the eight patients given 5-ALA who did not show any visible fluorescence, none were high-grade gliomas, and all were low-grade gliomas. Of the seven patients suspected radiologically of malignant transformation of low-grade gliomas and with visible fluorescence at surgery, six were diagnosed with high-grade gliomas, and one had no tissue collected. Conclusion. In patients where there is clinical suspicion, visible 5-ALA fluorescence has clinical utility as an intraoperative surgical biomarker of high-grade gliomas and can aid surgical decision-making and sampling. Further studies assessing the use of 5-ALA to assess malignant transformation in all diffuse gliomas may be valuable.

Pharmacokinetics and Biodistribution of 89Zr-Miltuximab and Its Antibody Fragments as Glypican-1 Targeting Immuno-PET Agents in Glioblastoma

Glioblastoma (GBM) is the most aggressive form of primary brain cancer, accounting for about 85% of all primary central nervous system (CNS) tumors. With standard treatment strategies like surgery, radiation, and chemotherapy, the median survival time of patients with GBM is only 12-15 months from diagnosis. The poor prognosis of GBM is due to a very high tumor recurrence rate following initial treatment, indicating a dire need for improved diagnostic and therapeutic alternatives for this disease. Antibody-based immunotheranostics holds great promise in treating GBM, combining the theranostic applications of radioisotopes and target-specificity of antibodies. In this study, we developed and validated antibody-based positron emission tomography (PET) tracers targeting the heparan sulfate proteoglycan, glypican-1 (GPC-1), for noninvasive detection of disease using diagnostic molecular imaging. GPC-1 is overexpressed in multiple solid tumor types, including GBM, and is a promising biomarker for novel immunotheranostics. Here, we investigate zirconium-89 (⁸⁹Zr)-conjugated Miltuximab (a clinical stage anti-GPC-1 monoclonal antibody developed by GlyTherix, Ltd.) and engineered fragments for their potential as immuno-PET tracers to detect GPC-1^positive GBM tumors in preclinical models. We explore the effects of molecular size, avidity, and Fc-domain on the pharmacokinetics and biodistribution in vivo, by comparing in parallel the full-length antibody (Miltuximab), Fab'2, Fab, and single-chain variable fragment (scFv) formats. High radiolabeling efficiency (>95%) was demonstrated by all the formats and the stability post-radiolabeling was higher for larger constructs of Miltuximab and the Fab. Receptor-mediated internalization of all ⁸⁹Zr-labeled formats was observed in a human GBM cell line in vitro, while full-length Miltuximab demonstrated the highest tumor retention (5.7 ± 0.94% ID/g, day-9 postinjection (p.i.)) and overall better tumor-to-background ratios than the smaller Fc-less formats. Results from in vivo PET image quantification and ex vivo scintillation counting were highly correlated. Altogether, ⁸⁹Zr-DFO-Miltuximab appears to be an effective immuno-PET imaging agent for detecting GPC-1^positive tumors such as GBM and the current results support utility of the Fc containing whole mAb format over smaller antibody fragments for this target.

Expression and Prognostic Value of CD80 and CD86 in the Tumor Microenvironment of Newly Diagnosed Glioblastoma

BACKGROUND

Strategies to modulate the tumor microenvironment (TME) have opened new therapeutic avenues with dramatic yet heterogeneous intertumoral efficacy in multiple cancers, including glioblastomas (GBMs). Therefore, investigating molecular actors of TME may help understand the interactions between tumor cells and TME. Immune checkpoint proteins such as a Cluster of Differentiation 80 (CD80) and CD86 are expressed on the surface of tumor cells and infiltrative tumor lymphocytes. However, their expression and prognostic value in GBM microenvironment are still unclear.

METHODS

In this study, we investigated, in a retrospective local discovery cohort and a validation TCGA dataset, expression of CD80 and CD86 at mRNA level and their prognostic significance in response to standard of care. Furthermore, CD80 and CD86 at the protein level were investigated in the discovery cohort.

RESULTS

Both CD80 and CD86 are expressed heterogeneously in the TME at mRNA and protein levels. In a univariate analysis, the mRNA expression of CD80 and CD86 was not significantly correlated with OS in both local OncoNeuroTek dataset and TCGA datasets. CD80 and CD86 mRNA high expression was significantly associated with shorter progression free survival (PFS) (p < 0.05). These findings were validated using the TCGA cohort; higher CD80 and CD86 expressions were correlated with shorter PFS (p < 0.05). In multivariate analysis, CD86 mRNA expression was an independent prognostic factor for PFS in the TCGA dataset only (p < 0.05).

CONCLUSION

CD86 could be used as a potential biomarker for the prognosis of GBM patients treated with immunotherapy; however, additional studies are needed to validate these findings.

Analyzing the role of reoperation in recurrent glioblastoma: a 15-year retrospective study in a single institution

BACKGROUND

Multiple treatment options at glioblastoma progression exist, including reintervention, reirradiation, additional systemic therapy, and novel strategies. No alternative has been proven to be superior in terms of postprogression survival (PPS). A second surgery has shown conflicting evidence in the literature regarding its prognostic impact, possibly affected by selection bias, and might benefit a sparse subset of patients with recurrent glioblastoma. The present study aims to determine the prognostic influence of salvage procedures in a cohort of patients treated in the same institution over 15 years.

METHODS

Three hundred and fifty patients with confirmed primary glioblastoma diagnosed and treated between 2005 and 2019 were selected. To examine the role of reoperation, we intended to create comparable groups, previously excluding all diagnostic biopsies and patients who were not actively treated after the first surgery or at disease progression. Uni- and multivariate Cox proportional hazards regression models were employed, considering reintervention as a time-fixed or time-dependent covariate. The endpoints of the study were overall survival (OS) and PPS.

RESULTS

At progression, 33 patients received a second surgery and 84 were treated with chemotherapy only. Clinical variables were similar among groups. OS, but not PPS, was superior in the reintervention group. Treatment modality had no impact in our multivariate Cox regression models considering OS or PPS as the endpoint.

CONCLUSIONS

The association of reoperation with improved prognosis in recurrent glioblastoma is unclear and may be influenced by selection bias. Regardless of our selective indications and high gross total resection rates in second procedures, we could not observe a survival advantage.

Postoperative communicating hydrocephalus following glioblastoma resection: Incidence, timing and risk factors

Introduction

Glioblastoma (GBM) is the most common malignant primary brain tumor. Treatment includes maximally safe surgical resection followed by radiation and/or chemotherapy. However, resection can lead to ventricular opening, potentially increasing the risk for development of communicating hydrocephalus (CH). Complications such as rebleeding and infection may also lead to CH and, eventually, the need for cerebrospinal fluid (CSF) diversion surgery. In this study, we evaluated the incidence of different types of hydrocephalus and potential risk factors for the development of CH following glioblastoma resection.

Methods

726 GBM patients who underwent tumor resection at our department between 2006 and 2019 were analyzed retrospectively. Potential risk factors that were determined for each patient were age, sex, tumor location, the number of resection surgeries, ventricular opening during resection, postoperative CSF leak, ventriculitis, and rebleeding. Uni- as well as multivariate analyses were performed to identify associations with CH and independent risk factors.

Results

55 patients (7.6%) needed CSF diversion surgery (implantation of a ventriculoperitoneal or ventriculoatrial shunt) following resection surgery. 47 patients (6.5%) had CH, on median, 24 days after the last resection (interquartile range: 17-52 days). 3 patients had obstructive hydrocephalus (OH) and 5 patients had other CSF circulation disorders. Ventricular opening (odds ratio (OR): 7.9; p=0.000807), ventriculitis (OR 3.3; p=0.000754), and CSF leak (OR 2.3; p=0.028938) were identified as significant independent risk factors for the development of post-resection CH. Having more than one resection surgery was associated with CH as well (OR 2.1; p=0.0128), and frontal tumors were more likely to develop CH (OR 2.4; p=0.00275), while temporal tumors were less likely (OR 0.41; p=0.0158); However, none of those were independent risk factors. Age, sex, or rebleeding were not associated with postoperative CH.

Conclusion

Postoperative CH requiring CSF shunting is not infrequent following GBM resection and is influenced by surgery-related factors. It typically occurs several weeks after resection. If multiple risk factors are present, one should discuss the possibility of postoperative CH with the patient and maybe even consider pre-emptive shunt implantation to avoid interruption of adjuvant tumor therapy. The incidence of CH requiring shunting in GBM patients could rise in the future.

Nanotherapeutic treatment of the invasive glioblastoma tumor microenvironment

Glioblastoma (GBM) is the most common malignant adult brain cancer with no curative treatment strategy. A significant hurdle in GBM treatment is effective therapeutic delivery to the brain-invading tumor cells that remain following surgery within functioning brain regions. Developing therapies that can either directly target these brain-invading tumor cells or act on other cell types and molecular processes supporting tumor cell invasion and recurrence are essential steps in advancing new treatments in the clinic. This review highlights some of the drug delivery strategies and nanotherapeutic technologies that are designed to target brain-invading GBM cells or non-neoplastic, invasion-supporting cells residing within the GBM tumor microenvironment.

Antibody-Based Formats to Target Glioblastoma: Overcoming Barriers to Protein Drug Delivery

Glioblastoma (GB) is recognized as the most aggressive form of primary brain cancer. Despite advances in treatment strategies that include surgery, radiation, and chemotherapy, the median survival time (∼15 months) of patients with GB has not significantly improved. The poor prognosis of GB is also associated with a very high chance of tumor recurrence (∼90%), and current treatment measures have failed to address the complications associated with this disease. However, targeted therapies enabled through antibody engineering have shown promise in countering GB when used in combination with conventional approaches. Here, we discuss the challenges in conventional as well as future GB therapeutics and highlight some of the known advantages of using targeted biologics to overcome these impediments. We also review a broad range of potential alternative routes that could be used clinically to administer anti-GB biologics to the brain through evasion of its natural barriers.

Can inflammasomes promote the pathophysiology of glioblastoma multiforme? A view about the potential of the anti-inflammasome therapy as pharmacological target

Glioblastoma multiforme (GBM) is a malignant brain tumor with one of the worst general survivorship cases among the existing neoplasia. This aggressiveness is due to its complex molecular heterogeneity, immunohistochemistry and genetics. The current therapeutic approach brings little contribution to the improvement of the survival of the patients. Due to that, new forms of treatment have been explored, one of them being immunotherapy. In this aspect, the inflammasome pathway, which induces inflammation and immunosuppressive tumor response, contributing to the progression of the tumor, seems to be a new alternative to improve the treatment efficacy and the survival of the patients.

Glioma Stem Cells Upregulate CD39 Expression to Escape Immune Response through SOX2 Modulation

Simple Summary

Glioblastoma is the most malignant tumor of the central nervous system. Glioma stem cells are the cause of adverse outcomes such as early recurrence and low overall survival in glioma patients. Targeting glioma stem cells is considered a promising anti-glioma strategy, Although CD39 plays a key role in the initiation and regulation of DC-mediated antigen-specific immune responses, its impact on GSCs is unclear. Therefore, we systematically investigated the effect of CD39 on extracellular ATP levels, dendritic cell recruitment and T cell killing in glioma stem cells. The molecular mechanism by which SOX2 binds to the CD39 promoter to regulate extracellular ATP levels, and evaluated the immune response enhanced by inhibition of CD39 after ADM treatment in a mouse glioma model. We suggest that CD39 is an effective target for glioma immunotherapy.

Abstract

Ectonucleotidase CD39 hydrolyzing extracellular ATP (eATP) functions as a key modulator of immune response in the tumor microenvironment, yet the role of CD39 in contributing tumor stem cells in a more immunosuppressive microenvironment remains elusive. Here we report that the upregulation of CD39 is crucial for the decrease of extracellular ATP concentration around glioma stem cells (GSCs) to maintain an immunosuppressive microenvironment. Adriamycin (ADM) is able to promote the release of ATP, which recruits dendritic cells (DCs) to phagocytose GSCs. CD39 inhibition further increased extracellular ATP concentrations following ADM treatment and DCs phagocytosis. In addition, GSCs upregulated CD39 expression by SOX2-binding CD39 promotor. In mouse tumor models, the combination of ADM and CD39 blockade increased immune cell infiltration and reduced tumor size. These findings suggest that GSCs upregulate CD39 expression by their biological characteristics to maintain an immunosuppressive microenvironment, and CD39 inhibition supplies a favorable tumor microenvironment (TME) for immunotherapeutic intervention and enhances the immune response induced by chemotherapy.

Lactate-Loaded Nanoparticles Induce Glioma Cytotoxicity and Increase the Survival of Rats Bearing Malignant Glioma Brain Tumor

A glioblastoma is an aggressive form of a malignant glial-derived tumor with a poor prognosis despite multimodal therapy approaches. Lactate has a preponderant role in the tumor microenvironment, playing an immunoregulatory role as well as being a carbon source for tumor growth. Lactate homeostasis depends on the proper functioning of intracellular lactate regulation systems, such as transporters and enzymes involved in its synthesis and degradation, with evidence that an intracellular lactate overload generates metabolic stress on tumor cells and tumor cell death. We propose that the delivery of a lactate overload carried in nanoparticles, allowing the intracellular release of lactate, would compromise the survival of tumor cells. We synthesized and characterized silica and titania nanoparticles loaded with lactate to evaluate the cellular uptake, metabolic activity, pH modification, and cytotoxicity on C6 cells under normoxia and chemical hypoxia, and, finally, determined the survival of an orthotopic malignant glioma model after in situ administration. A dose-dependent reduction in metabolic activity of treated cells under normoxia was found, but not under hypoxia, independent of glucose concentration. Lactated-loaded silica nanoparticles were highly cytotoxic (58.1% of dead cells) and generated significant supernatant acidification. In vivo, lactate-loaded silica nanoparticles significantly increased the median survival time of malignant glioma-bearing rats (p = 0.005) when administered in situ. These findings indicate that lactate-loaded silica nanoparticles are cytotoxic on glioma cells in vitro and in vivo.

Factors Influencing the Improvement of Activities of Daily Living during Inpatient Rehabilitation in Newly Diagnosed Patients with Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most common and aggressive brain tumor. To identify the factors influencing the improvement of the activities of daily living (ADL) in newly diagnosed patients with GBM, we investigated the characteristics and variable factors and overall survival. A total of 105 patients with GBM were retrospectively analyzed and categorized into the following three groups according to the quartile of change of their Barthel index score from admission to discharge: deterioration (n = 25), no remarkable change (n = 55), and good recovery (n = 25). A statistical difference was observed in the pre-operative, intra-operative, post-operative, and rehabilitation-related factors between the deterioration and good recovery groups. Multiple regression analysis identified the following significant factors that may influence the improvement of ADL after surgery: the improvement of motor paralysis after surgery, mild fatigue during radio and chemotherapy, and length up to early walking training onset. The median overall survival was significantly different between the deterioration (10.6 months) and good recovery groups (18.9 months, p = 0.025). Our findings identified several factors that may be associated with post-operative functional improvement in patients with GBM. The inpatient rehabilitation during radio and chemotherapy may be encouraged without severe adverse events and can promote functional outcomes, which may contribute to the overall survival of newly diagnosed patients with GBM.

Red blood cell distribution width in glioblastoma

INTRODUCTION

Glioblastoma (GBM) is the most common and deadly adult brain tumor. Red blood cell distribution width (RDW) has been found in non-central nervous system neoplasms to be associated with survival. This study aims to assess the prognostic value of pre-operative RDW and trends in RDW over time during the disease course.

METHODS

This single-institution retrospective cohort study identified patients ≥ 18 years old with pathology-proved glioblastoma treated between April 2003-May 2017 from an institutional database. A Cox proportional hazards model was developed using known prognostic clinical variables to predict overall survival time; a second model incorporating continuously valued RDW was then created. The additional prognostic value of RDW was assessed with a joint model F-test. The variation of RDW-CV over time was evaluated with linear mixed model of RDW. A post-hoc exploratory analysis was performed to assess the trend in RDW lab value leading up to time of death.

RESULTS

346 adult GBM patients were identified; complete survival data was available for all patients. The addition of RDW to the multivariable Cox proportional hazards model did not increase prognostic value. There was an upward trend in RDW throughout the post-operative disease course. In a post-hoc analysis, there was an upward trend in RDW leading up to the time of death.

CONCLUSION

Although RDW has been prognostic of survival for many inflammatory, prothrombotic, and neoplastic diseases, pre-operative RDW was not associated with overall survival in GBM patients. RDW trended upwards throughout the disease course, suggesting possible systemic inflammatory effects of either glioblastoma or treatment.

Clinical Targeting of Altered Metabolism in High-Grade Glioma

ABSTRACT

High-grade gliomas are among the deadliest of all cancers despite standard treatments, and new therapeutic strategies are needed to improve patient outcome. Targeting the altered metabolic state of tumors with traditional chemotherapeutic agents has a history of success, and our increased understanding of cellular metabolism in the past 2 decades has reinvigorated the concept of novel metabolic therapies in brain tumors. Here we highlight metabolic alterations in advanced gliomas and their translation into clinical trials using both novel agents and already established drugs repurposed for cancer treatment in an effort to improve outcome for these deadly diseases.

The phenomenon of multidrug resistance in glioblastomas

The most common and aggressive brain tumor in the adult population is glioblastoma (GBM). The lifespan of patients does not exceed 22 months. One of the reasons for the low effectiveness of GBM treatment is its radioresistance and chemoresistance. In the current review, we discuss the phenomenon of multidrug resistance of GBM in the context of the expression of ABC family transporter proteins and the mechanisms of proliferation, angiogenesis, and recurrence. We focused on the search of molecular targets among growth factors, receptors, signal transduction proteins, microRNAs, transcription factors, proto-oncogenes, tumor suppressor genes, and their single-nucleotide polymorphisms.

Potential Use of Nitrogen-Doped Carbon Nanotube Sponges as Payload Carriers Against Malignant Glioma

Glioblastoma is the most aggressive brain tumor with a low median survival of 14 months. The only Food and Drug Administration (FDA)-approved treatment for topical delivery of the cancer drug carmustine is Gliadel. However, its use has been associated with several side-effects, mainly provoked by a mass effect. Nitrogen-doped carbon nanotube sponges (N-CNSs) are a new type of nanomaterial exhibiting high biocompatibility, and they are able to load large amounts of hydrophobic drugs, reducing the amount of carriers. This study evaluated the use of N-CNSs as potential carmustine carriers using malignant glioma cell lines. N-CNSs were characterized by nanoparticle tracking analysis and transmission electron microscopy. The biocompatibility of N-CNSs was determined in glioma cell lines and in primary astrocytes. Afterward, N-CNSs were loaded with carmustine (1:10 w/w), and the drug and liberation efficiency, as well as cytotoxicity induction, were determined. N-CNSs presented a homogeneous size distribution formed by round nanotubes, without induced cytotoxicity, at concentrations below 40 µg/mL. The N-CNSs loaded with carmustine exhibited a continuous kinetic release of carmustine with a maximum release after 72 h. The cytotoxic effect of N-CNSs loaded with carmustine was similar to that of carmustine alone. The results demonstrated that N-CNSs are a biocompatible nanostructure that could be used as carriers for the tumoral load of large amounts of chemotherapeutic agents.

Cannabidiol Μay Prolong Survival in Patients With Glioblastoma Multiforme

BACKGROUND

Glioblastoma multiforme (GBM) is a relatively rare type of brain tumour with an incidence rate around 6 per 100,000. Even with the widely practiced combination of radiotherapy with adjuvant temozolomide, the median overall survival remains low with just 13.5 to 16 months after diagnosis.

PATIENTS AND METHODS

We retrospectively reviewed the survival of a cohort of 15 consecutive, unselected patients with histopathologically confirmed glioblastoma multiforme (GBM) who received CBD (400 to 600 mg orally per day) in addition to standard therapy (maximum resection of the tumour followed by radio-chemotherapy).

RESULTS

Of 15 patients, seven (46.7%) are now living for at least 24 months, and four (26.7%) for at least 36 months. This is more than twice as long as has been previously reported in the literature. The mean overall survival is currently 24.2 months (median 21 months).

CONCLUSION

CBD is a well supported co-medication and seems to prolong the survival of patients with glioblastoma multiforme.

Targeting the PD-1/PD-L1 pathway in glioblastoma multiforme: Preclinical evidence and clinical interventions

Glioblastoma multiforme (GBM), as one of the immunosuppressive and common intrinsic brain tumors in adults, remains an intractable malignancy to manage. Since the standard of care for treatment, which includes surgery and chemoradiation, has not provided a sustainable and durable response in affected patients, seeking novel therapeutic approaches to treat GBM seems imperative. Immunotherapy, a breakthrough for cancer treatment, has become an attractive tool for combating cancer with the potential to access the blood-brain-barrier (BBB). In this regard, programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1), as major immunological checkpoints, have drawn considerable interest due to their effectiveness in a spectrum of highly-aggressive neoplasms through negative regulation of the T-cell-mediated immune response. Nevertheless, due to the immunosuppressive microenvironment of GBM, the efficacy of these immune checkpoint inhibitors (ICIs), when used as monotherapy, has been unfavorable and lacks sufficient beneficial outcomes for GBM patients. A variety of clinical studies are attempting to evaluate the combination of ICIs (neoadjuvant/adjuvant) and existing treatment guidelines to strengthen their effectiveness; however, the exact mechanism of this signaling axis affects the consequences of immune therapy remains elusive. This review provides an overview of the PD-1/PD-L1 pathway, currently approved ICIs for clinical use, preclinical and clinical trials of PD-1/PD-L1 as monotherapy, and when used concomitantly with other GBM treatments.

FOXG1 mediates the radiosensitivity of glioma cells through regulation of autophagy

BACKGROUND/AIM

Upregulation of Forkhead box G1 (FOXG1) has recently been observed in many cancers, while its effect on radiosensitivity in glioma is still unclear. In this study, we hypothesized that FOXG1 be a major player in radioresistance of glioma as well as the underlying mechanism.

METHODS

Immunohistochemistry (IHC) was conducted to assess FOXG1 expression in glioma tissues and glioma-adjacent tissues. Western Blot was implemented to detect the expression of autophagy-related proteins. CCK-8, colony formation and flow cytometry assays were implemented to assess cell viability, proliferation and apoptosis, respectively. Transmission electron microscope (TEM) was used to observe autophagic vesicles. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assay was applied to detect the expression of FOXG1.

RESULTS

The present study demonstrated that FOXG1 was highly expressed in glioma tissues. FOXG1 expression level was up-regulated in glioma cells following exposure to X-ray irradiation. FOXG1 can attenuate radiosensitivity of glioma cells. Moreover, it revealed that FOXG1 attenuate radiosensitivity of glioma cells by promoting autophagy.

CONCLUSIONS

The present study suggests that FOXG1 is a pivotal molecule for circumventing radiation-induced cell death in malignant glioma cells through the regulation of autophagy, and it may be a target for the treatment of human brain glioma.

Glioblastoma with a primitive neuroectodermal component: two cases with implications for glioblastoma cell-of-origin

BACKGROUND

Glioblastoma (GBM) is the most common primary brain malignancy, but much remains unknown about the histogenesis of these tumors. In the great majority of cases, GBM is a purely glial tumor but in rare cases the classic-appearing high-grade glioma component is admixed with regions of small round blue cells with neuronal immunophenotype, and these tumors have been defined in the WHO 2016 Classification as "glioblastoma with a primitive neuronal component."

METHODS

In this paper, we present two cases of GBM-PNC with highly divergent clinical courses, and review current theories for the GBM cell-of-origin.

RESULTS AND CONCLUSIONS

GBM-PNC likely arises from a cell type competent to give rise to glial or neuronal lineages. The thesis that GBM recapitulates to some extent normal neurodevelopmental cellular pathways is supported by molecular and clinical features of our two cases of GBM-PNC, but more work is needed to determine which cellular precursor gives rise to specific cases of GBM. GBM-PNC may have a dramatically altered clinical course compared to standard GBM and may benefit from specific lines of treatment.

A brain tumor-homing tetra-peptide delivers a nano-therapeutic for more effective treatment of a mouse model of glioblastoma

Organ-specific cell-penetrating peptides (CPPs) are a class of molecules that can be highly effective at delivering therapeutic cargoes, and they are currently of great interest in cancer treatment strategies. Herein, we describe a new CPP (amino acid sequence serine-isoleucine-tyrosine-valine, or SIWV) that homes to glioblastoma multiforme (GBM) brain tumor tissues with remarkable specificity in vitro and in vivo. The SIWV sequence was identified from an isoform of annexin-A3 (AA3H), a membrane-interacting human protein. The mechanism of intracellular permeation is proposed to follow a caveolin-mediated endocytotic pathway, based on in vitro and in vivo receptor inhibition and genetic knockdown studies. Feasibility as a targeting agent for therapeutics is demonstrated in a GBM xenograft mouse model, where porous silicon nanoparticles (pSiNPs) containing the clinically relevant anticancer drug SN-38 are grafted with SIWV via a poly-(ethylene glycol) (PEG) linker. The formulation shows enhanced in vivo targeting ability relative to a formulation employing a scrambled control peptide, and significant (P < 0.05) therapeutic efficacy relative to free SN-38 in the GBM xenograft animal model.

Modeling human pediatric and adult gliomas in immunocompetent mice through costimulatory blockade

Currently, human glioma tumors are mostly modeled in immunodeficient recipients; however, lack of interactions with adaptive immune system is a serious flaw, particularly in the era when immunotherapies dominate treatment strategies. Our group was the first to successfully establish the orthotopic transplantation of human glioblastoma (GBM) in immunocompetent mice by inducing immunological tolerance using a short-term, systemic costimulation blockade strategy (CTLA-4-Ig and MR1). In this study, we further validated the feasibility of this method by modeling pediatric diffuse intrinsic pontine glioma (DIPG) and two types of adult GBM (GBM1, GBM551), in mice with intact immune systems and immunodeficient mice. We found that all three glioma models were successfully established, with distinct difference in tumor growth patterns and morphologies, after orthotopic xenotransplantation in tolerance-induced immunocompetent mice. Long-lasting tolerance that is maintained for up to nearly 200 d in GBM551 confirmed the robustness of this model. Moreover, we found that tumors in immunocompetent mice displayed features more similar to the clinical pathophysiology found in glioma patients, characterized by inflammatory infiltration and strong neovascularization, as compared with tumors in immunodeficient mice. In summary, we have validated the robustness of the costimulatory blockade strategy for tumor modeling and successfully established three human glioma models including the pediatric DIPG whose preclinical study is particularly thwarted by the lack of proper animal models.

lncRNA and mRNA signature for prognosis prediction of glioblastoma

Aims: We aimed to find out potential novel biomarkers for prognosis of glioblastoma (GBM). Materials & methods: We downloaded mRNA and lncRNA expression profiles of 169 GBM and five normal samples from The Cancer Genome Atlas and 129 normal brain samples from genotype-tissue expression. We use R language to perform the following analyses: differential RNA expression analysis of GBM samples using 'edgeR' package, survival analysis taking count of single or multiple gene expression level using 'survival' package, univariate and multivariate Cox regression analysis using Cox function plugged in 'survival' package. Gene ontology and Kyoto encyclopedia of genes and genomes pathway analysis were performed using FunRich tool online. Results and conclusion: We obtained differentially DEmRNAs and DElncRNAs in GBM samples. Most prognostically relevant mRNAs and lncRNAs were filtered out. 'GPCR ligand binding' and 'Class A/1' are found to be of great significance. In short, our study provides novel biomarkers for prognosis of GBM.

Expression profiling of single cells and patient cohorts identifies multiple immunosuppressive pathways and an altered NK cell phenotype in glioblastoma

Glioblastoma (GBM) is an aggressive cancer with a very poor prognosis. Generally viewed as weakly immunogenic, GBM responds poorly to current immunotherapies. To understand this problem more clearly we used a combination of natural killer (NK) cell functional assays together with gene and protein expression profiling to define the NK cell response to GBM and explore immunosuppression in the GBM microenvironment. In addition, we used transcriptome data from patient cohorts to classify GBM according to immunological profiles. We show that glioma stem-like cells, a source of post-treatment tumour recurrence, express multiple immunomodulatory cell surface molecules and are targeted in preference to normal neural progenitor cells by natural killer (NK) cells ex vivo. In contrast, GBM-infiltrating NK cells express reduced levels of activation receptors within the tumour microenvironment, with hallmarks of transforming growth factor (TGF)-β-mediated inhibition. This NK cell inhibition is accompanied by expression of multiple immune checkpoint molecules on T cells. Single-cell transcriptomics demonstrated that both tumour and haematopoietic-derived cells in GBM express multiple, diverse mediators of immune evasion. Despite this, immunome analysis across a patient cohort identifies a spectrum of immunological activity in GBM, with active immunity marked by co-expression of immune effector molecules and feedback inhibitory mechanisms. Our data show that GBM is recognized by the immune system but that anti-tumour immunity is restrained by multiple immunosuppressive pathways, some of which operate in the healthy brain. The presence of immune activity in a subset of patients suggests that these patients will more probably benefit from combination immunotherapies directed against multiple immunosuppressive pathways.

A Comparative Analysis of the Usefulness of Survival Prediction Models for Patients with Glioblastoma in the Temozolomide Era: The Importance of Methylguanine Methyltransferase Promoter Methylation, Extent of Resection, and Subventricular Zone Location

OBJECTIVE

Several survival prediction models for patients with glioblastoma have been proposed, but none is widely used. This study aims to identify the predictors of overall survival (OS) and to conduct an independent comparative analysis of 5 prediction models.

METHODS

Multi-institutional data from 159 patients with newly diagnosed glioblastoma who received adjuvant temozolomide concomitant chemoradiotherapy (CCRT) were collected. OS was assessed by Cox proportional hazards regression and adjusted for known prognostic factors. An independent CCRT patient cohort was used to externally validate the 1) RTOG (Radiation Therapy Oncology Group) recursive partitioning analysis (RPA) model, 2) Yang RPA model, and 3) Wee RPA model, Chaichana model, and the RTOG nomogram model. The predictive accuracy for each model at 12-month survival was determined by concordance indices. Calibration plots were performed to ascertain model prediction precision.

RESULTS

The median OS for patients who received CCRT was 19.0 months compared with 12.7 months for those who did not (P < 0.001). Independent predictors were: 1) subventricular zone II tumors (hazard ratio [HR], 1.6; 95% confidence interval [CI], 1.0-2.5); 2) methylguanine methyltransferase promoter methylation (HR, 0.36; 95% CI, 0.2-0.6); and 3) extent of resection of >85% (HR, 0.59; 95% CI, 0.4-0.9). For 12-month OS prediction, the RTOG nomogram model was superior to the RPA models with a c-index of 0.70. Calibration plots for 12-month survival showed that none of the models was precise, but the RTOG nomogram performed relatively better.

CONCLUSIONS

The RTOG nomogram best predicted 12-month OS. Methylguanine methyltransferase promoter methylation status, subventricular zone tumor location, and volumetric extent of resection should be considered when constructing prediction models.

Evolutionary basis of a new gene- and immune-therapeutic approach for the treatment of malignant brain tumors: from mice to clinical trials for glioma patients

Glioma cells are one of the most aggressive and malignant tumors. Following initial surgery, and radio-chemotherapy they progress rapidly, so that patients' median survival remains under two years. They invade throughout the brain, which makes them difficult to treat, and are universally lethal. Though total resection is always attempted it is not curative. Standard of care in 2016 comprises surgical resection, radiotherapy and chemotherapy (temozolomide). Median survival is currently ~14-20months post-diagnosis though it can be higher in high complexity medical university centers, or during clinical trials. Why the immune system fails to recognize the growing brain tumor is not completely understood. We believe that one reason for this failure is that the brain lacks cells that perform the role that dendritic cells serve in other organs. The lack of functional dendritic cells from the brain causes the brain to be deficient in priming systemic immune responses to glioma antigens. To overcome this drawback we reconstituted the brain immune system for it to initiate and prime anti-glioma immune responses from within the brain. To achieve brain immune reconstitution adenoviral vectors are injected into the resection cavity or remaining tumor. One adenoviral vector expresses the HSV-1 derived thymidine kinase which converts ganciclovir into phospho-ganciclovir which becomes cytotoxic to dividing cells. The second adenovirus expresses the cytokine fms-like tyrosine kinase 3 ligand (Flt3L). Flt3L differentiates precursors into dendritic cells and acts as a chemokine for dendritic cells. This results in HSV-1/ganciclovir killing of tumor cells, and the release of tumor antigens, which are then taken up by dendritic cells recruited to the brain tumor microenvironment by Flt3L. Concomitant release of HMGB1, a TLR2 agonist that activates dendritic cells, stimulates dendritic cells loaded with glioma antigens to migrate to the cervical lymph nodes to prime a systemic CD8+ T cytotoxic killing of brain tumor cells. This induced immune response causes glioma-specific cytotoxicity, induces immunological memory, and does not cause brain toxicity or autoimmunity. A Phase I Clinical Trial, to test our hypothesis in human patients, was opened in December 2013 (see: NCT01811992, Combined Cytotoxic and Immune-Stimulatory Therapy for Glioma, at ClinicalTrials.gov). This trial is a first in human trial to test whether the re-engineering of the brain immune system can serve to treat malignant brain tumors. The long and winding road from the laboratory to the clinical trial follows below.

The Survival Advantage of "Supratotal" Resection of Glioblastoma Using Selective Cortical Mapping and the Subpial Technique

BACKGROUND

A substantial body of evidence suggests that cytoreductive surgery is a prerequisite to prolonging survival in patients with glioblastoma (GBM).

OBJECTIVE

To evaluate the safety and impact of "supratotal" resections beyond the zone of enhancement seen on magnetic resonance imaging scans, using a subpial technique.

METHODS

We retrospectively evaluated 86 consecutive patients with primary GBM, managed by the senior author, using a subpial resection technique with or without carmustine (BCNU) wafer implantation. Multivariate Cox proportional hazards regression was used to analyze clinical, radiological, and outcome variables. Overall impacts of extent of resection (EOR) and BCNU wafer placement were compared using Kaplan-Meier survival analysis.

RESULTS

Mean patient age was 56 years. The median OS for the group was 18.1 months. Median OS for patients undergoing gross total, near-total, and subtotal resection were 54, 16.5, and 13.2 months, respectively. Patients undergoing near-total resection ( P = .05) or gross total resection ( P < .01) experienced statistically significant longer survival time than patients undergoing subtotal resection as well as patients undergoing ≥95% EOR ( P < .01) when compared to <95% EOR. The addition of BCNU wafers had no survival advantage.

CONCLUSIONS

The subpial technique extends the resection beyond the contrast enhancement and is associated with an overall survival beyond that seen in similar series where resection of the enhancement portion is performed. The effect of supratotal resection on survival exceeded the effects of age, Karnofsky performance score, and tumor volume. A prospective study would help to quantify the impact of the subpial technique on quality of life and survival as compared to a traditional resection limited to the enhancing tumor.

Outcomes after second surgery for recurrent glioblastoma: a retrospective case-control study

Studies looking at the benefit of surgery at first relapse (second surgery) for recurrent glioblastoma were confounded by including patients with varying grades of glioma, performance status and extent of resection. This case-controlled study aims to remove these confounders to assess the survival impact of second surgery in recurrent glioblastoma. Retrospective data on patients with glioblastoma recurrence at two tertiary Australian hospitals from July 2009 to April 2015 was reviewed. Patients who had surgery at recurrence were matched with those who did not undergo surgery at recurrence, based on the extent of their initial resection and age. Overall survival (OS1 assessed from initial diagnosis and OS2 from the date of recurrence) as well as functional outcomes after resection were analysed. There were 120 patients (60 in each institution); median age at diagnosis was 56 years. Median OS1 was 14 months (95% CI 11.5-15.7) versus 22 months (95% CI 18-25) in patients who did not undergo second surgery and those with surgery at recurrence. OS2 was improved by second surgery (4.7 vs 9.6, HR 0.52, 95% CI 0.38-0.72, P < 0.001), and by chemotherapy, given at recurrence, (HR 0.47, 95% CI 0.24-0.92, P = 0.03). After second surgery, 80% did not require rehabilitation and 61% were independently mobile. Second surgery for recurrent glioblastoma was associated with a survival advantage. Chemotherapy independent of surgery, also improved survival. Functional outcomes were encouraging. More research is required in the era of improved surgical techniques and new antineoplastic therapies.

Epidermal growth factor receptor activity is elevated in glioma cancer stem cells and is required to maintain chemotherapy and radiation resistance

Glioblastoma remains among the most aggressive of all human and canine malignancies, displaying high mortality rates and limited treatment options. We propose that given the similarities between canine and human gliomas, such as incidence of occurrence, histopathology, molecular characteristics, and response to therapy, that canine gliomas are a natural model of the human disease. A range of human and canine tumours have been shown to harbor specific subpopulations of cells with stem cell-like properties that initiate and maintain neoplasticity while resisting conventional therapies. Here, we show that both canine and human glioma cell lines contain a small population of cancer stem cells (CSCs), and by molecular profiling highlight the important role of the epidermal growth factor receptor (EGFR) pathway in canine CSCs. EGFR signaling is crucial in the regulation of cancer cell proliferation, migration and survival. To date EGFR-targeted interventions alone have been largely ineffective. Our findings confirm that specifically inhibiting EGFR signaling alone has no significant effect on the viability of CSCs. However inhibition of EGFR did enhance the chemo- and radio-sensitivity of both canine and human glioma CSCs, enabling this resistant, tumourigenic population of cells to be effectively targeted by conventional therapies.

Advanced MRI Techniques in the Monitoring of Treatment of Gliomas

OPINION STATEMENT

With advances in treatments and survival of patients with glioblastoma (GBM), it has become apparent that conventional imaging sequences have significant limitations both in terms of assessing response to treatment and monitoring disease progression. Both 'pseudoprogression' after chemoradiation for newly diagnosed GBM and 'pseudoresponse' after anti-angiogenesis treatment for relapsed GBM are well-recognised radiological entities. This in turn has led to revision of response criteria away from the standard MacDonald criteria, which depend on the two-dimensional measurement of contrast-enhancing tumour, and which have been the primary measure of radiological response for over three decades. A working party of experts published RANO (Response Assessment in Neuro-oncology Working Group) criteria in 2010 which take into account signal change on T2/FLAIR sequences as well as the contrast-enhancing component of the tumour. These have recently been modified for immune therapies, which are associated with specific issues related to the timing of radiological response. There has been increasing interest in quantification and validation of physiological and metabolic parameters in GBM over the last 10 years utilising the wide range of advanced imaging techniques available on standard MRI platforms. Previously, MRI would provide structural information only on the anatomical location of the tumour and the presence or absence of a disrupted blood-brain barrier. Advanced MRI sequences include proton magnetic resonance spectroscopy (MRS), vascular imaging (perfusion/permeability) and diffusion imaging (diffusion weighted imaging/diffusion tensor imaging) and are now routinely available. They provide biologically relevant functional, haemodynamic, cellular, metabolic and cytoarchitectural information and are being evaluated in clinical trials to determine whether they offer superior biomarkers of early treatment response than conventional imaging, when correlated with hard survival endpoints. Multiparametric imaging, incorporating different combinations of these modalities, improves accuracy over single imaging modalities but has not been widely adopted due to the amount of post-processing analysis required, lack of clinical trial data, lack of radiology training and wide variations in threshold values. New techniques including diffusion kurtosis and radiomics will offer a higher level of quantification but will require validation in clinical trial settings. Given all these considerations, it is clear that there is an urgent need to incorporate advanced techniques into clinical trial design to avoid the problems of under or over assessment of treatment response.

The Long and Winding Road: From the High-Affinity Choline Uptake Site to Clinical Trials for Malignant Brain Tumors

Malignant brain tumors are one of the most lethal cancers. They originate from glial cells which infiltrate throughout the brain. Current standard of care involves surgical resection, radiotherapy, and chemotherapy; median survival is currently ~14-20 months postdiagnosis. Given that the brain immune system is deficient in priming systemic immune responses to glioma antigens, we proposed to reconstitute the brain immune system to achieve immunological priming from within the brain. Two adenoviral vectors are injected into the resection cavity or remaining tumor. One adenoviral vector expresses the HSV-1-derived thymidine kinase which converts ganciclovir into a compound only cytotoxic to dividing glioma cells. The second adenovirus expresses the cytokine fms-like tyrosine kinase 3 ligand (Flt3L). Flt3L differentiates precursors into dendritic cells and acts as a chemokine that attracts dendritic cells to the brain. HSV-1/ganciclovir killing of tumor cells releases tumor antigens that are taken up by dendritic cells within the brain tumor microenvironment. Tumor killing also releases HMGB1, an endogenous TLR2 agonist that activates dendritic cells. HMGB1-activated dendritic cells, loaded with glioma antigens, migrate to cervical lymph nodes to stimulate a systemic CD8+ T cells cytotoxic immune response against glioma. This immune response is specific to glioma tumors, induces immunological memory, and does neither cause brain toxicity nor autoimmune responses. An IND was granted by the FDA on 4/7/2011. A Phase I, first in person trial, to test whether reengineering the brain immune system is potentially therapeutic is ongoing.