Comprehensive portrait of recurrent glioblastoma multiforme in molecular and clinical characteristics

Targeting androgen receptor in glioblastoma

Glioblastomas are primary brain tumors that originate from glial stem cells or progenitor cells. There is a large difference in the incidence of glioblastoma between males and females. Studies revealed that the gender differences in the tumor may be attributable to the androgen receptor signaling axis. The incidence rate of glioblastoma in men is higher than that in women. Aberrant activation of the androgen receptor signaling pathway, or interactions between the androgen receptor signaling axis and other signaling axes promote the development of glioblastoma. Therefore, targeting the androgen receptor holds promise as a therapeutic approach for glioblastoma. This review investigates the dynamics of drug research into the treatment of glioblastoma by targeting the androgen receptor. The first finding in line with expectations is that androgen receptor antagonists, represented by enzalutamide, have been studied and shown to have anti-glioblastoma effects. In addition, it was found that the combination of 5-alpha reductase inhibitors and androgen receptor antagonists resulted in better therapeutic outcomes than each of them alone. Similar results were obtained with the combination of an epidermal growth factor receptor inhibitor and an androgen receptor antagonist. In addition, four small molecule compounds have been shown to exert significant anti-glioblastoma effects by directly or indirectly targeting the androgen receptor. Expectantly, one of these small molecules, seviteronel, progressed to the phase II clinical trial stage. These findings suggest that targeting the androgen receptor for glioblastoma may be a promising therapeutic option.

Pyk2/FAK Signaling Is Upregulated in Recurrent Glioblastoma Tumors in a C57BL/6/GL261 Glioma Implantation Model

The majority of glioblastomas (GBMs) recur shortly after tumor resection and recurrent tumors differ significantly from newly diagnosed GBMs, phenotypically and genetically. In this study, using a Gl261-C57Bl/6 mouse glioma implantation model, we identified significant upregulation of proline-rich tyrosine kinase Pyk2 and focal adhesion kinase (FAK) phosphorylation levels-pPyk2 (579/580) and pFAK (925)-without significant modifications in total Pyk2 and FAK protein expression in tumors regrown after surgical resection, compared with primary implanted tumors. Previously, we demonstrated that Pyk2 and FAK are involved in the regulation of tumor cell invasion and proliferation and are associated with reduced overall survival. We hypothesized that the use of inhibitors of Pyk2/FAK in the postsurgical period may reduce the growth of recurrent tumors. Using Western blot analysis and confocal immunofluorescence approaches, we demonstrated upregulation of Cyclin D1 and the Ki67 proliferation index in tumors regrown after resection, compared with primary implanted tumors. Treatment with Pyk2/FAK inhibitor PF-562271, administered through oral gavage at 50 mg/kg daily for two weeks beginning 2 days before tumor resection, reversed Pyk2/FAK signaling upregulation in recurrent tumors, reduced tumor volume, and increased animal survival. In conclusion, the use of Pyk2/FAK inhibitors can contribute to a delay in GBM tumor regrowth after surgical resection.

Recent advances and future challenges of tumor vaccination therapy for recurrent glioblastoma

Glioblastoma (GBM) is the most malignant CNS tumor with a highest incidence rate, and most patients would undergo a recurrence. Recurrent GBM (rGBM) shows an increasing resistance to chemotherapy and radiotherapy, leading to a significantly poorer prognosis and the urgent need for novel treatments. Immunotherapy, a rapidly developing anti-tumor therapy in recent years, has shown its potential value in rGBM. Recent studies on PD-1 immunotherapy and CAR-T therapy have shown some efficacy, but the outcome was not as expected. Tumor vaccination is the oldest approach of immunotherapies, which has returned to the research focus because of the failure of other strategies and subversive understanding of CNS. The isolation effect of blood brain barrier and the immunosuppressive cell infiltration could lead to resistance existing in all phases of the anti-tumor immune response, where novel tumor vaccines have been designed to overcome these problems through new tumor antigenic targets and regulatory of the systematic immune response. In this review, the immunological characteristics of CNS and GBM would be discussed and summarized, as well as the mechanism of each novel tumor vaccine for rGBM. And through the review of completed early-phase studies and ongoing large-scale phase III clinical trials, evaluation could be conducted for potential immune response, biosecurity and initial clinical outcome, which further draw a panorama of this vital research field and provide some deep thoughts for the prospective tendency of vaccination strategy. Video Abstract.

The Pathological Activation of Microglia Is Modulated by Sexually Dimorphic Pathways

Microglia are the primary immunocompetent cells of the central nervous system (CNS). Their ability to survey, assess and respond to perturbations in their local environment is critical in their role of maintaining CNS homeostasis in health and disease. Microglia also have the capability of functioning in a heterogeneous manner depending on the nature of their local cues, as they can become activated on a spectrum from pro-inflammatory neurotoxic responses to anti-inflammatory protective responses. This review seeks to define the developmental and environmental cues that support microglial polarization towards these phenotypes, as well as discuss sexually dimorphic factors that can influence this process. Further, we describe a variety of CNS disorders including autoimmune disease, infection, and cancer that demonstrate disparities in disease severity or diagnosis rates between males and females, and posit that microglial sexual dimorphism underlies these differences. Understanding the mechanism behind differential CNS disease outcomes between men and women is crucial in the development of more effective targeted therapies.

Bifunctional cancer cell-based vaccine concomitantly drives direct tumor killing and antitumor immunity

The administration of inactivated tumor cells is known to induce a potent antitumor immune response; however, the efficacy of such an approach is limited by its inability to kill tumor cells before inducing the immune responses. Unlike inactivated tumor cells, living tumor cells have the ability to track and target tumors. Here, we developed a bifunctional whole cancer cell-based therapeutic with direct tumor killing and immunostimulatory roles. We repurposed the tumor cells from interferon-β (IFN-β) sensitive to resistant using CRISPR-Cas9 by knocking out the IFN-β-specific receptor and subsequently engineered them to release immunomodulatory agents IFN-β and granulocyte-macrophage colony-stimulating factor. These engineered therapeutic tumor cells (ThTCs) eliminated established glioblastoma tumors in mice by inducing caspase-mediated cancer cell apoptosis, down-regulating cancer-associated fibroblast-expressed platelet-derived growth factor receptor β, and activating antitumor immune cell trafficking and antigen-specific T cell activation signaling. This mechanism-based efficacy of ThTCs translated into a survival benefit and long-term immunity in primary, recurrent, and metastatic cancer models in immunocompetent and humanized mice. The incorporation of a double kill-switch comprising herpes simplex virus-1 thymidine kinase and rapamycin-activated caspase 9 in ThTCs ensured the safety of our approach. Arming naturally neoantigen-rich tumor cells with bifunctional therapeutics represents a promising cell-based immunotherapy for solid tumors and establishes a road map toward clinical translation.

Symptoms of Depression and Anxiety in Adults with High-Grade Glioma: A Literature Review and Findings in a Group of Patients before Chemoradiotherapy and One Year Later

Simple Summary

High-grade glioma (HGG) is the most severe type of brain cancer. At different stages of the disease, affected persons are at high risk of symptoms of depression and anxiety. If undiagnosed and untreated, these symptoms might become severe and compromise the patient’s quality of life. Improved knowledge on the prevalence, mechanisms and clinical risk factors underlying the etiology of depression and anxiety in this population is required. This may help to increase awareness on the importance of integrating consistent assessment of mood symptoms with the clinical follow-up and provide insights for developing personalized psychosocial interventions.

Abstract

High-grade glioma (HGG) is associated with several external and internal stressors that may induce mood alterations at all stages of the disease. Symptoms of depression and anxiety in persons with glioma have multifactorial etiology and require active follow-up. We reviewed the literature data on the prevalence, mechanisms likely involved in the etiology of mood alterations in persons with HGG and psychosocial interventions found beneficial in treating these symptoms. We also investigated the prevalence and clinical variables that could increase the risk of depression and anxiety symptoms in a group of patients with HGG at two disease time-points: after surgery, before and 1 year after chemoradiotherapy. Literature findings revealed complex mechanisms underlying these symptoms and highlighted the importance of providing early access to palliative care. Our results show a high rate of anxiety and depression symptoms in the first stage of the disease and increased concomitance of these symptoms at the 1-year follow-up. Depression and anxiety symptoms at 1 year after the end of chemoradiotherapy were associated with the presence of symptoms at the first stage of the disease and tumor progression. Antiepileptic drugs and corticosteroid intake did not increase the risk of depressive and anxious symptoms among patients. Active management of mood alterations is an essential part of the care and contributes to patients’ well-being and quality of life.

KDELR1 Is an Independent Prognostic Predictor and Correlates With Immunity in Glioma

Background

Gliomas are the most malignant central nervous system tumors. With the development of sequencing technology, more potential biomarkers related to the treatment, prognosis, and molecular classification of glioma have been identified. Here, we intend to investigate the potential biological function and clinical value of a new biomarker in glioma.

Methods

KDELR1 expression data and the corresponding clinical information were downloaded from public databases and then preprocessed using R language. Correlation, Kaplan–Meier survival, and Cox regression analyses were performed to explore the clinical significance of KDELR1 in glioma patients. Furthermore, the immune infiltration and microenvironment parameters were evaluated via TIMER and CIBERSORT. Immunohistochemistry was conducted to confirm the KDELR1 expression and its correlation with immunity infiltration and prognosis.

Results

KDELR1 was upregulated in glioma samples compared with normal brain tissues, and its expression was significantly correlated with age, the World Health Organization (WHO) grade, recurrence, necrosis, microvascular proliferation, molecular classification, isocitrate dehydrogenase (IDH) mutation, and 1p/19q codeletion status. In addition, survival analysis showed that glioma patients with KDELR1 overexpression had shorter overall survival (OS) and disease-free survival times, and Cox regression analysis revealed that KDELR1 acted as an independent prognostic factor of OS in glioma patients. Gene set enrichment analysis indicated a significant enrichment of metabolism-associated pathways. KDELR1 expression was positively associated with immune infiltration (including infiltration by CD8+ T cells, CD4+ T cells, macrophages, and so on) and microenvironment parameters (including stromal, immune, and ESTIMATE scores) in gliomas. The expression of KDELR1 and its correlation with the tumor grade and prognosis were confirmed by immunohistochemistry in clinical samples (n = 119, P < 0.05).

Conclusions

Taken together, these findings suggest that KDELR1 is correlated with the tumor grade, molecular classifications, and immune infiltration; highlighting that KDELR1 is a novel and promising biomarker for molecular classification, treatment, and prognostic assessment may further indicate the treating effect of immune therapy.

Congress of neurological surgeons systematic review and evidence-based guidelines update on the role of neuropathology in the management of progressive glioblastoma in adults

TARGET POPULATION

These recommendations apply to adult patients with progressive or recurrent glioblastoma (GBM).

QUESTION

For adult patients with progressive glioblastoma does testing for Isocitrate Dehydrogenase (IDH) 1 or 2 mutations provide new additional management or prognostic information beyond that derived from the tumor at initial presentation?

RECOMMENDATION

Level III: Repeat IDH mutation testing is not necessary if the tumor is histologically similar to the primary tumor and the patient's clinical course is as expected.

QUESTION

For adult patients with progressive glioblastoma does repeat testing for MGMT promoter methylation provide new or additional management or prognostic information beyond that derived from the tumor at initial presentation and what methods of detection are optimal?

RECOMMENDATION

Level III: Repeat MGMT promoter methylation is not recommended.

QUESTION

For adult patients with progressive glioblastoma does EGFR amplification or mutation testing provide management or prognostic information beyond that provided by histologic analysis and if performed on previous tissue samples, does it need to be repeated?

RECOMMENDATION

Level III: In cases that are difficult to classify as glioblastoma on histologic features EGFR amplification testing may help in classification. If a previous EGFR amplification was detected, repeat testing is not necessary. Repeat EGFR amplification or mutational testing may be recommended in patients in which target therapy is being considered.

QUESTION

For adult patients with progressive glioblastoma does large panel or whole genome sequencing provide management or prognostic information beyond that derived from histologic analysis?

RECOMMENDATION

Level III: Primary or repeat large panel or whole genome sequencing may be considered in patients who are eligible or interested in molecularly guided therapy or clinical trials.

QUESTION

For adult patients with progressive glioblastoma should immune checkpoint biomarker testing be performed to provide management and prognostic information beyond that obtained from histologic analysis?

RECOMMENDATION

Level III: The current evidence does not support making PD-L1 or mismatch repair (MMR) enzyme activity a component of standard testing.

QUESTION

For adult patients with progressive glioblastoma are there meaningful biomarkers for bevacizumab responsiveness and does their assessment provide additional information for tumor management and prognosis beyond that learned by standard histologic analysis?

RECOMMENDATION

Level III: No established Bevacizumab biomarkers are currently available based upon the inclusion criteria of this guideline.

Study of Glioblastomas According to Clinicopathological Parameters

Background: Glioblastomas are the most common tumors of the central nervous system. The incidence of brain tumors is higher in developed countries and is constantly increasing.

Aim of the study: The purpose of this study was to analyze the clinicopathological data of patients diagnosed with glioblastomas from a selected case series.

Material and methods: This retrospective, single-center study was conducted on glioblastoma cases diagnosed between 2014 and 2018 at the Department of Pathology of the County Emergency Clinical Hospital of Târgu Mureș, Romania. The information was centralized from histopathology reports and focused on the location of glioblastomas and demographic parameters (gender and age of patients).

Results: In the studied period, there were 154 patients diagnosed with glioblastoma, of which 50.65% were men. The most affected age group was 61–70 years (31.17% of cases). In most cases (49.35%), the glioblastoma was located in the left cerebral hemisphere, and the most affected lobes were the frontal (29.87%), temporal (26.62%), and parietal (14.94%). We could not find a statistically significant association between the distribution of cases by years, gender, and location of the tumor.

Conclusions: Glioblastoma is a tumor that involves the left cerebral hemisphere most often and affects both genders over the age of sixty.

Interstitial Control-Released Polymer Carrying a Targeting Small-Molecule Drug Reduces PD-L1 and MGMT Expression in Recurrent High-Grade Gliomas with TMZ Resistance

Simple Summary

This study reports a potential new drug—Cerebraca wafer—that is designed to deliver its active pharmaceutical ingredient, (Z)-n-butylidenephthalide (BP), directly into the surgical cavity created when a brain tumor is resected. The therapeutic mechanism of Cerebraca wafer was shown to involve the following: (1) an IC₅₀ of BP against tumor stem cells four times lower than that of bis-chloroethylnitrosourea (BCNU); (2) a synergistic effect between BP and temozolomide (TMZ), as demonstrated by a reduction in O⁶-methylguanine-DNA-methyltransferase (MGMT) expression level; (3) BP inhibition of programmed cell death-ligand 1 (PD-L1) protein levels, thereby activating T-cell cytotoxicity and increasing interferon-gamma (IFN-γ) secretion. The implantation of Cerebraca wafer is safe, no drug-related adverse events (AEs) and serious AEs (SAEs) were found. The median overall survival (OS) of patients receiving high-dose Cerebraca wafer have exceeded 17.4 months, and a 100% progression-free survival (PFS) rate at six month was achieved. In sum, these findings demonstrate that the Cerebraca wafer has superior therapeutic effects to Gliadel wafer in recurrent high-grade gliomas.

Abstract

In recurrent glioblastoma, Gliadel wafer implantation after surgery has been shown to result in incomplete chemical removal of residual tumor and development of brain edema. Furthermore, temozolomide (TMZ) resistance caused by O⁶-methylguanine-DNA-methyltransferase (MGMT) activation and programmed cell death-ligand 1 (PD-L1) expression leads to immune-cold lesions that result in poorer prognosis. Cerebraca wafer, a biodegradable polymer containing (Z)-n-butylidenephthalide (BP), is designed to eliminate residual tumor after glioma resection. An open-label, one-arm study with four dose cohorts, involving a traditional 3 + 3 dose escalation clinical trial, of the Cerebraca wafer combined with TMZ on patients with recurrent high-grade glioma, was conducted. Of the 12 patients who receive implantation of Cerebraca wafer, there were no drug-related adverse events (AEs) or serious AEs (SAEs). The median overall survival (OS) of patients receiving low-dose Cerebraca wafer was 12 months in the group with >25% wafer coverage of the resected tumor, which is longer than OS duration in previously published studies (Gliadel wafer, 6.4 months). Patients who received high-dose Cerebraca wafer treatment had not yet died at the data cut-off date; a 100% progression-free survival (PFS) rate at six month was achieved, indicating the median OS of cohort IV was more than 17.4 months. In vitro study of the primary cells collected from the patients revealed that the IC₅₀ of BP against tumor stem cells was four times lower than that of bis-chloroethylnitrosourea (BCNU). A synergistic effect between BP and TMZ was demonstrated by a reduction in MGMT expression. Furthermore, BP inhibited PD-L1 expression, thereby activating T-cell cytotoxicity and increasing interferon-gamma (IFN-γ) secretion. The better therapeutic effect of Cerebraca wafer on recurrent high-grade glioma could occur through re-sensitization of TMZ and reduction of PD-L1.

An overview of current therapeutic strategies for glioblastoma and the role of CD73 as an alternative curative approach

Glioblastoma multiforme (GBM) is a complicated and heterogeneous brain tumor with short-term survival outcomes. Commercial therapies are not practical due to cell infiltration capacity, high proliferative rate, and blood-brain barrier. In this context, recognition of the molecular mechanism of tumor progression might help the development of new cancer therapeutics. Recently, more evidence has supported CD73 and downstream adenosine A2A/A2B receptor signaling playing a crucial role in glioblastoma pathogenesis; therefore, targeting CD73 in murine tumor models can reduce tumor development. CD73 is an ecto-enzyme inducing tumor metastasis, angiogenesis, and immune escape via the production of extracellular adenosine in the tumor microenvironment. In this review, we provided information about clinical characteristics as well as the therapeutic management of glioblastoma. Then, we focused on newly available experimental evidence distinguishing between the essential role of CD73 on this tumor growth and a new method for the treatment of GBM patients.

Sex-Specific Differences in Glioblastoma

Sex differences have been well identified in many brain tumors. Even though glioblastoma (GBM) is the most common primary malignant brain tumor in adults and has the worst outcome, well-established differences between men and women are limited to incidence and outcome. Little is known about sex differences in GBM at the disease phenotype and genetical/molecular level. This review focuses on a deep understanding of the pathophysiology of GBM, including hormones, metabolic pathways, the immune system, and molecular changes, along with differences between men and women and how these dimorphisms affect disease outcome. The information analyzed in this review shows a greater incidence and worse outcome in male patients with GBM compared with female patients. We highlight the protective role of estrogen and the upregulation of androgen receptors and testosterone having detrimental effects on GBM. Moreover, hormones and the immune system work in synergy to directly affect the GBM microenvironment. Genetic and molecular differences have also recently been identified. Specific genes and molecular pathways, either upregulated or downregulated depending on sex, could potentially directly dictate GBM outcome differences. It appears that sexual dimorphism in GBM affects patient outcome and requires an individualized approach to management considering the sex of the patient, especially in relation to differences at the molecular level.

Targeting FGL2, a molecular drug target for glioblastoma, with natural compounds through virtual screening method

Background: Fibroleukin-2 protein (FGL2) causes redevelopment of brain tumors. Inhibition of these proteins has shown to improve glioblastoma prognosis and treatment efficacy. Aim: The current study gathered recently exploited natural compounds that suppress glioblastoma proliferation in vitro, tested against FGL2 protein. Method: Twenty-five compounds were explored through a virtual screening platform. Results: Three natural compounds (betanine, hesperetin and ovatodiolide) hit the active site of FGL2. Furthermore, the influence of these compounds was also assessed using in silico gene expression, and ADMET tools showed downregulation of some genes, which caused rapid tumor development while possessing a moderate acute toxicity and pharmacokinetic profile. Conclusion: Our study presents three compounds that are good candidates for evaluation in FGL2 mutated glioblastoma animal models.

The Fibronectin Expression Determines the Distinct Progressions of Malignant Gliomas via Transforming Growth Factor-Beta Pathway

Due to the increasing incidence of malignant gliomas, particularly glioblastoma multiforme (GBM), a simple and reliable GBM diagnosis is needed to screen early the death-threaten patients. This study aimed to identify a protein that can be used to discriminate GBM from low-grade astrocytoma and elucidate further that it has a functional role during malignant glioma progressions. To identify proteins that display low or no expression in low-grade astrocytoma but elevated levels in GBM, glycoprotein fibronectin (FN) was particularly examined according to the mining of the Human Protein Atlas. Web-based open megadata minings revealed that FN was mainly mutated in the cBio Cancer Genomic Portal but dominantly overexpressed in the ONCOMINE (a cancer microarray database and integrated data-mining platform) in distinct tumor types. Furthermore, numerous different cancer patients with high FN indeed exhibited a poor prognosis in the PrognoScan mining, indicating that FN involves in tumor malignancy. To investigate further the significance of FN expression in glioma progression, tumor specimens from five malignant gliomas with recurrences that received at least two surgeries were enrolled and examined. The immunohistochemical staining showed that FN expression indeed determined the distinct progressions of malignant gliomas. Furthermore, the expression of vimentin (VIM), a mesenchymal protein that is strongly expressed in malignant cancers, was similar to the FN pattern. Moreover, the level of epithelial-mesenchymal transition (EMT) inducer transforming growth factor-beta (TGF-β) was almost recapitulated with the FN expression. Together, this study identifies a protein FN that can be used to diagnose GBM from low-grade astrocytoma; moreover, its expression functionally determines the malignant glioma progressions via TGF-β-induced EMT pathway.

Immunotherapy for recurrent glioblastoma: practical insights and challenging prospects

Glioblastoma (GB) is the most common high-grade intracranial malignant tumor with highly malignant biological behavior and a high recurrence rate. Although anti-PD-1/PD-L1 antibodies have achieved significant survival benefits in several kinds of solid tumors, the phase III clinical trial Checkmate 143 demonstrated that nivolumab, which targets PD-1, did not achieve survival benefits compared with bevacizumab in recurrent glioblastoma (rGB) patients. Nevertheless, neoadjuvant anti-PD-1 therapy followed by surgery and adjuvant anti-PD-1 therapy could effectively activate local and systemic immune responses and significantly improve the OS of rGB patients. Furthermore, several studies have also confirmed the progress made in applying tumor-specific peptide vaccination or chimeric antigen receptor-T (CAR-T) cell therapy to treat rGB patients, and successes with antibodies targeting other inhibitory checkpoints or costimulatory molecules have also been reported. These successes inspired us to explore candidate combination treatments based on anti-PD-1/PD-L1 antibodies. However, effective predictive biomarkers for clinical efficacy are urgently needed to avoid economic waste and treatment delay. Attempts to prolong the CAR-T cell lifespan and increase T cell infiltration through engineering techniques are addressing the challenge of strengthening T cell function. In this review, we describe the immunosuppressive molecular characteristics of rGB; clinical trials exploring anti-PD-1/PD-L1 therapy, tumor-specific peptide vaccination, and CAR-T cell therapy; candidate combination strategies; and issues related to strengthening T cell function.

SAA1 knockdown promotes the apoptosis of glioblastoma cells via downregulation of AKT signaling

Serum amyloid A1 (SAA1) is an inflammatory associated high-density lipoprotein. And It is also considered as a predictor and prognostic marker of cancer risk. However, its role and mechanisms in glioblastoma (GBM) still unclear. In this study, we validate that SAA1 is up-regulated in GBM, and its high expression predicts poor prognosis. SAA1 knockdown promotes the apoptosis of GBM cell. Mechanistically, SAA1 knockdown can inhibit serine/threonine protein kinase B (AKT) phosphorylation, thereby regulating the expression of apoptosis-related proteins such as Bcl2 and Bax, leading to GBM cell death. Moreover, Gliomas with low SAA1 expression have increased sensitivity to Temozolomide (TMZ). Low SAA1 expression segregated glioma patients who were treated with Temozolomide (TMZ) or with high MGMT promoter methylation into survival groups in TCGA and CGGA dataset. Our study strongly suggested that SAA1 was a regulator of cells apoptosis and acted not only as a prognostic marker but also a novel biomarker of sensitivity of glioma to TMZ.

The Impact of Surgery on the Survival of Patients with Recurrent Glioblastoma

Objective:

The purpose of this study was to investigate the possible benefit of repeat surgery on overall survival for patients with recurrent glioblastoma multiforme (GBM).

Methods:

We performed a retrospective analysis of data from patients who presented with recurrent GBM over a 5-year period (n = 157), comparing baseline characteristics and survival for patients who had at least 1 new tumor resection followed by chemotherapy (reoperation group, n = 59) and those who received medical treatment only (no-reoperation group, n = 98) for recurrence.

Results:

The baseline characteristics of the two groups differed in terms of WHO performance status (better in the reoperation group), mean age (60 years in the reoperation group vs. 65 years in the no-reoperation group), mean interval to recurrence (3 months later in the reoperation group than in the no-reoperation group) and more gross total resections in the reoperation group. Nevertheless, the patients in the reoperation group had a higher rate [32.8%] of sensorimotor deficits than those of the no-reoperation group [14.2]. There was no significant difference in sex; tumor localization, side, or extent; MGMT status; MIB-1 labeling index; or Karnofsky Performance Status [KPS] score. After adjustment for age, the WHO performance status, interval of recurrence, and extent of resection at the first operation, multivariate analysis showed that median survival was significantly better in the reoperation group than in the no-reoperation group (22.9 vs. 14.61 months, P < 0.05). After a total of 69 repeat operations in 59 patients (10 had 2 repeat surgeries), we noted 13 temporary and 20 permanent adverse postoperative events, yielding a permanent complication rate of 28.99% (20/69). There was also a statistically significant (P = 0.029, Student's t-test) decrease in the mean KPS score after reoperation (mean preoperative KPS score of 89.34 vs. mean postoperative score of 84.91).

Conclusion:

Our retrospective study suggests that repeat surgery may be beneficial for patients with GBM recurrence who have good functional status (WHO performance status 0 and 1), although the potential benefits must be weighed against the risk of permanent complications, which occurred in almost 30% of the patients who underwent repeat resection in this series.

Longitudinal Characteristics of Glioblastoma in Genome-Wide Studies

Glioblastoma is one of the deadliest tumors with barely over one-year median survival despite intensive efforts in defining its molecular characteristics and searching for innovative treatment strategies. While major progress has been made in cataloging cross-sectional genomic, transcriptomic and epigenomic features of the tumor, and inferring its main molecular pathways and niches for potential targeted intervention, we still do not have sufficient knowledge concerning evolutionary patterns and dynamics of molecular changes or the treatment-induced effects affecting glioblastoma biology. In this review, we summarize the results of recent longitudinal genomic, transcriptomic and epigenomic studies that brought us closer to a better understanding of this lethal disease. Evidence suggests that neuronal / glioma stem cells with accumulating mutations initiate glioblastoma development and recurrence, but the hypothetical models describing the courses that lead to established tumors have not been fully proven. Moving from the histopathological phenotype to the results of high resolution OMICS studies, we try to synthesize the currently available information from sequential glioblastoma analyses in order to highlight its multifaceted features and heterogenetity, as well as the expected complexity of potential treatment strategies that might once succeed.

Current Opinion on Molecular Characterization for GBM Classification in Guiding Clinical Diagnosis, Prognosis, and Therapy

Glioblastoma (GBM) is highly invasive and the deadliest brain tumor in adults. It is characterized by inter-tumor and intra-tumor heterogeneity, short patient survival, and lack of effective treatment. Prognosis and therapy selection is driven by molecular data from gene transcription, genetic alterations and DNA methylation. The four GBM molecular subtypes are proneural, neural, classical, and mesenchymal. More effective personalized therapy heavily depends on higher resolution molecular subtype signatures, combined with gene therapy, immunotherapy and organoid technology. In this review, we summarize the principal GBM molecular classifications that guide diagnosis, prognosis, and therapeutic recommendations.

Single-Cell Atlas Reveals Complexity of the Immunosuppressive Microenvironment of Initial and Recurrent Glioblastoma

The Glioblastoma (GBM) immune microenvironment plays a critical role in tumor development, progression, and prognosis. A comprehensive understanding of the intricate milieu and its interactions remains unclear, and single-cell analysis is crucially needed. Leveraging mass cytometry (CyTOF), we analyzed immunocytes from 13 initial and three recurrent GBM samples and their matched peripheral blood mononuclear cells (pPBMCs). Using a panel of 30 markers, we provide a high-dimensional view of the complex GBM immune microenvironment. Hematoxylin and eosin staining and polychromatic immunofluorescence were used for verification of the key findings. In the initial and recurrent GBMs, glioma-associated microglia/macrophages (GAMs) constituted 59.05 and 27.87% of the immunocytes, respectively; programmed cell death-ligand 1 (PD-L1), T cell immunoglobulin domain and mucin domain-3 (TIM-3), lymphocyte activation gene-3 (LAG-3), interleukin-10 (IL-10) and transforming growth factor-β (TGFβ) demonstrated different expression levels in the GAMs among the patients. GAMs could be subdivided into different subgroups with different phenotypes. Both the exhausted T cell and regulatory T (Treg) cell percentages were significantly higher in tumors than in pPBMCs. The natural killer (NK) cells that infiltrated into the tumor lesions expressed higher levels of CXC chemokine receptor 3 (CXCR3), as these cells expressed lower levels of interferon-γ (IFNγ). The immune microenvironment in the initial and recurrent GBMs displayed similar suppressive changes. Our study confirmed that GAMs, as the dominant infiltrating immunocytes, present great inter- and intra-tumoral heterogeneity and that GAMs, increased exhausted T cells, infiltrating Tregs, and nonfunctional NK cells contribute to local immune suppressive characteristics. Recurrent GBMs share similar immune signatures with the initial GBMs except the proportion of GAMs decreases.

Role of endolysosomes and pH in the pathogenesis and treatment of glioblastoma

BACKGROUND

Glioblastoma multiforme (GBM) is a Grade IV astrocytoma with an aggressive disease course and a uniformly poor prognosis. Pathologically, GBM is characterized by rapid development of primary tumors, diffuse infiltration into the brain parenchyma, and robust angiogenesis. The treatment options that are limited and largely ineffective include a combination of surgical resection, radiotherapy, and chemotherapy with the alkylating agent temozolomide.

RECENT FINDINGS

Similar to many other forms of cancer, the extracellular environment near GBM tumors is acidified. Extracellular acidosis is particularly relevant to tumorgenesis and the concept of tumor cell dormancy because of findings that decreased pH reduces proliferation, increases resistance to apoptosis and autophagy, promotes tumor cell invasion, increases angiogenesis, obscures immune surveillance, and promotes resistance to drug and radio-treatment. Factors known to participate in the acidification process are nutrient starvation, oxidative stress, hypoxia and high levels of anaerobic glycolysis that lead to increases in lactate. Also involved are endosomes and lysosomes (hereafter termed endolysosomes), acidic organelles with highly regulated stores of hydrogen (H+) ions. Endolysosomes contain more than 60 hydrolases as well as about 50 proteins that are known to affect the number, sizes and distribution patterns of these organelles within cells. Recently, vacuolar ATPase (v-ATPase), the main proton pump that is responsible for maintaining the acidic environment in endolysosomes, was identified as a novel therapeutic target for glioblastoma.

CONCLUSIONS

Thus, a greater understanding of the role of endolysosomes in regulating cellular and extracellular acidity could result in a better elucidation of GBM pathogenesis and new therapeutic strategies.

Identification of subsets of IDH-mutant glioblastomas with distinct epigenetic and copy number alterations and stratified clinical risks

Background

IDH-mutant glioblastoma is classified by the 2016 CNS WHO as a group with good prognosis. However, the actual number of cases examined in the literature is relatively small. We hypothesize that IDH-mutant glioblastoma is not a uniform group and should be further stratified.

Methods

We conducted methylation profiles and estimated copy number variations of 57 IDH-mutant glioblastomas.

Results

Our results showed that 59.6% and 40.4% of tumors belonged to glioma-CpG island methylator phenotype (G-CIMP)-high and G-CIMP-low methylation subgroups, respectively. G-CIMP-low subgroup was associated with significantly worse overall survival (OS) as compared to G-CIMP-high (P = .005). CDKN2A deletion (42.1%) was the most common gene copy number variation, and was significantly associated with G-CIMP-low subgroup (P = .004). Other frequent copy number changes included mesenchymal-epithelial transition (MET) (5.3%), CCND2 (19.3%), PDGFRA (14.0%), CDK4 (12.3%), and EGFR (12.3%) amplification. Both CDKN2A deletion (P = .036) and MET amplification (P < .001) were associated with poor OS in IDH-mutant glioblastomas. Combined epigenetic signature and gene copy number variations separated IDH-mutant glioblastomas into Group 1 (G-CIMP-high), Group 2 (G-CIMP-low without CDKN2A nor MET alteration), and Group 3 (G-CIMP-low with CDKN2A and/or MET alteration). Survival analysis revealed Groups 1 and 2 exhibited a favorable OS (median survival: 619 d [20.6 mo] and 655 d [21.8 mo], respectively). Group 3 exhibited a significant shorter OS (median survival: 252 d [8.4 mo]). Multivariable analysis confirmed the independent prognostic significance of our Groups.

Conclusions

IDH-mutant glioblastomas should be stratified for risk with combined epigenetic signature and CDKN2A/MET status and some cases have poor outcome.

Relevance of a TCGA-derived Glioblastoma Subtype Gene-Classifier among Patient Populations

Glioblastoma multiforme (GBM), a deadly cancer, is the most lethal and common malignant brain tumor, and the leading cause of death in adult brain tumors. While genomic data continues to rocket, clinical application and translation to patient care are lagging behind. Big data now deposited in the TCGA network offers a window to generate novel clinical hypotheses. We hypothesized that a TCGA-derived gene-classifier can be applied across different gene profiling platforms and population groups. This gene-classifier validated three robust GBM-subtypes across six different platforms, among Caucasian, Korean and Chinese populations: Three Caucasian-predominant TCGA-cohorts (Affymetrix U133A = 548, Agilent Custom-Array = 588, RNA-seq = 168), and three Asian-cohorts (Affymetrix Human Gene 1.0ST-Array = 61, Illumina = 52, Agilent 4 × 44 K = 60). To understand subtype-relevance in patient therapy, we investigated retrospective TCGA patient clinical sets. Subtype-specific patient survival outcome was similarly poor and reflected the net result of a mixture of treatment regimens with/without surgical resection. As a proof-of-concept, in subtype-specific patient-derived orthotopic xenograft (PDOX) mice, Classical-subtype demonstrated no survival difference comparing radiation-therapy versus temozolomide monotherapies. Though preliminary, a PDOX model of Proneural/Neural-subtype demonstrated significantly improved survival with temozolomide compared to radiation-therapy. A larger scale study using this gene-classifier may be useful in clinical outcome prediction and patient selection for trials based on subtyping.

The Role of CXCR3 in Neurological Diseases

BACKGROUND

Neurological diseases have become an obvious challenge due to insufficient therapeutic intervention. Therefore, novel drugs for various neurological disorders are in desperate need. Recently, compelling evidence has demonstrated that chemokine receptor CXCR3, which is a G protein-coupled receptor in the CXC chemokine receptor family, may play a pivotal role in the development of neurological diseases. The aim of this review is to provide evidence for the potential of CXCR3 as a therapeutic target for neurological diseases.

METHODS

English journal articles that focused on the invovlement of CXCR3 in neurological diseases were searched via PubMed up to May 2017. Moreover, reference lists from identified articles were included for overviews.

RESULTS

The expression level of CXCR3 in T cells was significantly elevated in several neurological diseases, including multiple sclerosis (MS), glioma, Alzheimer's disease (AD), chronic pain, human T-lymphotropic virus type 1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and bipolar disorder. CXCR3 antagonists showed therapeutic effects in these neurological diseases.

CONCLUSION

These studies provided hard evidence that CXCR3 plays a vital role in the pathogenesis of MS, glioma, AD, chronic pain, HAM/TSP and bipolar disorder. CXCR3 is a crucial molecule in neuroinflammatory and neurodegenerative diseases. It regulates the activation of infiltrating cells and resident immune cells. However, the exact functions of CXCR3 in neurological diseases are inconclusive. Thus, it is important to understand the topic of chemokines and the scope of their activity in neurological diseases.

Decreased BRMS1L expression is correlated with glioma grade and predicts poor survival in glioblastoma via an invasive phenotype

AIMS

To evaluate the prognostic and clinicopathological features of glioma with BRMS1L expression.

METHODS

Total 120 glioma samples were obtained as discovery cohort. CGGA, GSE and TCGA datasets were obtained as validation sets. Furthermore, Kaplan-Meier survival and multivariate Cox analysis were used to evaluate the survival distributions. Moreover, the functional role of BRMS1L was also analyzed by transwell assay.

RESULTS

In the discovery cohort, decreased BRMS1L expression was significantly associated with high-grade glioma as well as the higher mortality in survival analysis (log-rank test, p< 0.01). And the three validation cohorts showed the similar results. Furthermore, BRMS1L act as an independent prognostic factor in glioblastoma patients. Additionally, functional assay showed that ectopic of BRMS1L suppressed glioma cells' invasion.

CONCLUSION

BRMS1L plays as an anti-oncogene in GBM and indicates a new potential therapeutic target.

Cell subpopulation deconvolution reveals breast cancer heterogeneity based on DNA methylation signature

Tumour heterogeneity describes the coexistence of divergent tumour cell clones within tumours, which is often caused by underlying epigenetic changes. DNA methylation is commonly regarded as a significant regulator that differs across cells and tissues. In this study, we comprehensively reviewed research progress on estimating of tumour heterogeneity. Bioinformatics-based analysis of DNA methylation has revealed the evolutionary relationships between breast cancer cell lines and tissues. Further analysis of the DNA methylation profiles in 33 breast cancer-related cell lines identified cell line-specific methylation patterns. Next, we reviewed the computational methods in inferring clonal evolution of tumours from different perspectives and then proposed a deconvolution strategy for modelling cell subclonal populations dynamics in breast cancer tissues based on DNA methylation. Further analysis of simulated cancer tissues and real cell lines revealed that this approach exhibits satisfactory performance and relative stability in estimating the composition and proportions of cellular subpopulations. The application of this strategy to breast cancer individuals of the Cancer Genome Atlas's identified different cellular subpopulations with distinct molecular phenotypes. Moreover, the current and potential future applications of this deconvolution strategy to clinical breast cancer research are discussed, and emphasis was placed on the DNA methylation-based recognition of intra-tumour heterogeneity. The wide use of these methods for estimating heterogeneity to further clinical cohorts will improve our understanding of neoplastic progression and the design of therapeutic interventions for treating breast cancer and other malignancies.

Long non-coding RNA MEG3 inhibits cell growth of gliomas by targeting miR-93 and inactivating PI3K/AKT pathway

Gliomas are the most common cancers in the brain, accompanied with high morbility, occurrence, disability and mortality. Long non-coding RNAs (lncRNAs) have been proposed as promoter or inhibitor in many cancer processes. Previous findings have indicated that lncRNA-maternally expressed gene 3 (MEG3) is involved in tumorigenesis of several cancers, including glioma. However, the underlying mechanism of MEG3 in glioma remains elusive. In our study, MEG3 was found downregulated in glioma tissues compared with normal brain tissues. Downregulated expression of MEG3 was also detected in two human glioma cell lines (U-251, M059J) compared with normal astrocyte cells. MEG3 was then overexpressed by ligating to a lentiviral vector. Overexpressed MEG3 inhibited the proliferation of U-251 cells, and restrained the expression of proliferation marker proteins Ki67 and proliferating cell nuclear antigen (PCNA). However, cell apoptosis rate of U-251 cells and the expression of apoptosis marker proteins (caspase-3 and caspase-9) were elevated by MEG3. Furthermore, miR-93 was predicted a direct target of lncRNA-MEG3 by bioinformatics analysis. Overexpressed MEG3 counteracted the role of miR-93 in facilitating proliferation and inhibiting apoptosis in U-251 cells. Moreover, MEG3 restained the activation of phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT) pathway by reducing cytomembrane translocation of AKT. Finally, the in vivo experiment revealed that MEG3 strongly reduced tumor growth, tumor volume and the expression of Ki67 and PCNA. lncRNA-MEG3 also inhibited the level of miR-93 and the expression of PI3K/AKT pathway related proteins in vivo. Taken together, our research indicated a MEG3-miR-93-PI3K-AKT pathway in regulating the growth of glioma, providing a promising therapy for glioma.

Sequential adaptive changes in a c-Myc-driven model of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a common cancer that frequently overexpresses the c-Myc (Myc) oncoprotein. Using a mouse model of Myc-induced HCC, we studied the metabolic, biochemical, and molecular changes accompanying HCC progression, regression, and recurrence. These involved altered rates of pyruvate and fatty acid β-oxidation and the likely re-directing of glutamine into biosynthetic rather than energy-generating pathways. Initial tumors also showed reduced mitochondrial mass and differential contributions of electron transport chain complexes I and II to respiration. The uncoupling of complex II's electron transport function from its succinate dehydrogenase activity also suggested a mechanism by which Myc generates reactive oxygen species. RNA sequence studies revealed an orderly progression of transcriptional changes involving pathways pertinent to DNA damage repair, cell cycle progression, insulin-like growth factor signaling, innate immunity, and further metabolic re-programming. Only a subset of functions deregulated in initial tumors was similarly deregulated in recurrent tumors thereby indicating that the latter can "normalize" some behaviors to suit their needs. An interactive and freely available software tool was developed to allow continued analyses of these and other transcriptional profiles. Collectively, these studies define the metabolic, biochemical, and molecular events accompanyingHCCevolution, regression, and recurrence in the absence of any potentially confounding therapies.

Management of glioblastoma after recurrence: A changing paradigm

Glioblastoma remains the most common primary brain tumor after the age of 40years. Maximal safe surgery followed by adjuvant chemoradiotherapy has remained the standard treatment for glioblastoma (GBM). But recurrence is an inevitable event in the natural history of GBM with most patients experiencing it after 6-9months of primary treatment. Recurrent GBM poses great challenge to manage with no well-defined management protocols. The challenge starts from differentiating radiation necrosis from true local progression. A fine balance needs to be maintained on improving survival and assuring a better quality of life. Treatment options are limited and ranges from re-excision, re-irradiation, systemic chemotherapy or a combination of these. Re-excision and re-irradiation must be attempted in selected patients and has been shown to improve survival outcomes. To facilitate the management of GBM recurrences, a treatment algorithm is proposed.