Bevacizumab plus radiotherapy-temozolomide for newly diagnosed glioblastoma

Timing of bevacizumab administration after biopsy for unresectable newly diagnosed glioblastoma

Background

Recent studies have revealed that bevacizumab (BEV) can improve the survival of patients with newly diagnosed unresectable glioblastoma (GBM) with poor performance status. For patients who develop early clinical deterioration, early initiation of BEV would be beneficial. However, the safety and feasibility of early initiation of BEV remain to be determined because of the lack of studies addressing adverse events associated with BEV initiation <28 days after surgery. The aim of this study was to analyze the risks and benefits of early BEV administration after biopsy in patients with newly diagnosed GBM.

Methods

Thirty-one consecutive patients with newly diagnosed GBM who underwent biopsy followed by BEV administration were investigated. The relationships between the timing of BEV administration and treatment response, survival outcome, and adverse events were analyzed.

Results

Response rates based on the RANO criteria and overall survival times were similar between the early and standard BEV groups. No wound dehiscence was observed in the early BEV group, and only one case was observed in the standard BEV group. Patients in the early BEV group were more likely to have undergone biopsy with a smaller skin incision than those in the standard BEV group. Equivalent treatment effects of BEV were achieved in patients who developed early clinical deterioration and those without clinical deterioration.

Conclusion

Early BEV administration is effective in controlling early clinical deterioration and does not increase the risk of wound-healing complications. Further studies with larger numbers of patients are needed to validate our results.

Characterization of Glioblastoma Cells Response to Regorafenib

Glioblastoma (GBM), the most malignant primary brain tumor in adults. Although not frequent, it has a relevant social impact because the peak incidence coincides with the age of professional maturity. A number of novel treatments have been proposed, yet clinical trials have been disappointing. Recently, a phase II clinical trial (REGOMA) demonstrated that the multikinase inhibitor regorafenib significantly increased the median overall survival (OS) of GBM patients when compared to lomustine-treated patients. On this basis, the National Comprehensive Cancer Network (NCCN) 2020 Guidelines included regorafenib as a preferred regimen in relapsed GBM treatment. Despite the use in GBM patients' therapy, little is known about the molecular mechanisms governing regorafenib effectiveness on the GBM tumor. Here we report an in vitro characterization of GBM tumor cells' response to regorafenib, performed both on cell lines and on patient-derived glioma stem cells (GSCs). Overall, regorafenib significantly reduced cell growth of 2D tumor cell cultures and of 3D tumor spheroids. Strikingly, this effect was accompanied by transcriptional regulation of epithelial to mesenchymal transition (EMT) genes and by an increased ability of surviving tumor cells to invade the surrounding matrix. Taken together, our data suggest that regorafenib limits cell growth, however, it might induce an invasive phenotype.

Lipid droplets and ferroptosis as new players in brain cancer glioblastoma progression and therapeutic resistance

A primary brain tumor glioblastoma is the most lethal of all cancers and remains an extremely challenging disease. Apparent oncogenic signaling in glioblastoma is genetically complex and raised at any stage of the disease's progression. Many clinical trials have shown that anticancer drugs for any specific oncogene aberrantly expressed in glioblastoma show very limited activity. Recent discoveries have highlighted that alterations in tumor metabolism also contribute to disease progression and resistance to current therapeutics for glioblastoma, implicating an alternative avenue to improve outcomes in glioblastoma patients. The roles of glucose, glutamine and tryptophan metabolism in glioblastoma pathogenesis have previously been described. This article provides an overview of the metabolic network and regulatory changes associated with lipid droplets that suppress ferroptosis. Ferroptosis is a newly discovered type of nonapoptotic programmed cell death induced by excessive lipid peroxidation. Although few studies have focused on potential correlations between tumor progression and lipid droplet abundance, there has recently been increasing interest in identifying key players in lipid droplet biology that suppress ferroptosis and whether these dependencies can be effectively exploited in cancer treatment. This article discusses how lipid droplet metabolism, including lipid synthesis, storage, and use modulates ferroptosis sensitivity or tolerance in different cancer models, focusing on glioblastoma.

Phase 2 study of AV-GBM-1 (a tumor-initiating cell targeted dendritic cell vaccine) in newly diagnosed Glioblastoma patients: safety and efficacy assessment

Background

Vaccine immunotherapy may improve survival in Glioblastoma (GBM). A multicenter phase II trial was designed to determine: (1) the success rate of manufacturing the Aivita GBM vaccine (AV-GBM-1), (2) Adverse Events (AE) associated with AV-GBM-1 administration, and (3) survival.

Methods

Fresh suspected glioblastoma tissue was collected during surgery, and patients with pathology-confirmed GBM enrolled before starting concurrent Radiation Therapy and Temozolomide (RT/TMZ) with Intent to Treat (ITT) after recovery from RT/TMZ. AV-GBM-1 was made by incubating autologous dendritic cells with a lysate of irradiated autologous Tumor-Initiating Cells (TICs). Eligible patients were adults (18 to 70 years old) with a Karnofsky Performance Score (KPS) of 70 or greater, a successful TIC culture, and sufficient monocytes collected. A cryopreserved AV-GBM-1 dose was thawed and admixed with 500 μg of Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) before every subcutaneous (s.c.) administration.

Results

Success rates were 97% for both TIC production and monocyte collection. AV-GBM-1 was manufactured for 63/63 patients; 60 enrolled per ITT; 57 started AV-GBM-1. The most common AEs attributed to AV-GBM-1 were local injection site reactions (16%) and flu-like symptoms (10%). Treatment-emergent AEs included seizures (33%), headache (37%), and focal neurologic symptoms (28%). One patient discontinued AV-GBM-1 because of seizures. Median Progression-Free Survival (mPFS) and median Overall Survival (mOS) from ITT enrollment were 10.4 and 16.0 months, respectively. 2-year Overall Survival (OS) is 27%.

Conclusions

AV-GBM-1 was reliably manufactured. Treatment was well-tolerated, but there were numerous treatment-emergent central nervous system AEs. mPFS was longer than historical benchmarks, though no mOS improvement was noted.

Trial registration

NCT, NCT03400917, Registered 10 January 2018,

Downregulation of ADAMTS3 Suppresses Stemness and Tumorigenicity in Glioma Stem Cell

AIMS

Glioblastoma multiforme (GBM) is the most aggressive type of human brain tumor, with a poor prognosis and a median overall survival of fewer than 15 months. Glioma stem cells (GSCs) have recently been identified as a key player in tumor initiation and therapeutic resistance in GBM. ADAMTS family of metalloproteinases is known to cleave a wide range of extracellular matrix substrates and has been linked to tissue remodeling events in tumor development. Here, we investigate that ADAMTS3 regulates GSC proliferation and self-renewal activities, and tumorigenesis in orthotopic xenograft models.

METHODS

ADAMTS3 mRNA expression levels in normal human astrocyte (NHA), glioma, and GSCs cell lines were compared. After knockdown of ADAMTS3, alamarBlue assay, in vitro limiting dilution, and orthotopic xenograft assays were performed. To investigate the tumor-associated roles of ADAMTS3, several statistical assays were conducted using publicly available datasets.

RESULTS

ADAMTS3 level was remarkably higher in GSCs than in NHA, glioma cell lines, and their matched differentiated tumor cells. Interestingly, knockdown of ADAMTS3 disrupted GSC's proliferation, self-renewal activity, and tumor formation in vivo. Furthermore, ADAMTS3 could be used as an independent predictor of malignancy progression in GBM.

CONCLUSION

We identified ADAMTS3 as a potential therapeutic target for GBM.

Immunotherapy approaches for adult glioma: knowledge gained from recent clinical trials

PURPOSE OF REVIEW

Summarize principles behind various immunotherapy approaches for high and low-grade glioma in the context of recently completed clinical trials and the new insights they provide.

RECENT FINDINGS

Despite the widespread success of therapies targeting the T-cell checkpoints programmed-death 1 and cytotoxic T lymphocyte antigen 4 in other malignancies, recent phase III trials in glioblastoma confirm the lack of efficacy of anti-programmed-death 1 monotherapy in more than 90% of patients. Vaccination approaches remain under investigation for high-grade glioma and have shown activity in some low-grade glioma patients. Chimeric antigen receptor T cells now feature a new generation of products engineered to potentially withstand glucocorticoid therapy. Oncolytic viral therapies have similarly advanced in sophistication, with drug-sensitive gene expression and tumor-selective modifications. Combinations of therapies hold promise for overcoming the numerous mechanisms of immune suppression in glioma.

SUMMARY

Although immunotherapies have yet to show rates of efficacy compared with other malignancies, new knowledge of immunology and combination therapies brings hope for improved efficacy in the future.

Treatment of Adult Gliomas: A Current Update

Gliomas are the most common type of primary brain tumor in adults. Glioma treatment requires a multidisciplinary approach involving surgery, radiotherapy, and chemotherapy. Multiple trials have been conducted to establish the appropriate choice of treatment to achieve long-term survival and better quality of life. This review provides up-to-date evidence regarding treatment strategies for gliomas.

Mutual regulation between phosphofructokinase 1 platelet isoform and VEGF promotes glioblastoma tumor growth

Glioblastoma (GBM) is a highly vascular malignant brain tumor that overexpresses vascular endothelial growth factor (VEGF) and phosphofructokinase 1 platelet isoform (PFKP), which catalyzes a rate-limiting reaction in glycolysis. However, whether PFKP and VEGF are reciprocally regulated during GBM tumor growth remains unknown. Here, we show that PFKP can promote EGFR activation-induced VEGF expression in HIF-1α-dependent and -independent manners in GBM cells. Importantly, we demonstrate that EGFR-phosphorylated PFKP Y64 has critical roles in both AKT/SP1-mediated transcriptional expression of HIF-1α and in the AKT-mediated β-catenin S552 phosphorylation, to fully enhance VEGF transcription, subsequently promoting blood vessel formation and brain tumor growth. Levels of PFKP Y64 phosphorylation in human GBM specimens are positively correlated with HIF-1α expression, β-catenin S552 phosphorylation, and VEGF expression. Conversely, VEGF upregulates PFKP expression in a PFKP S386 phosphorylation-dependent manner, leading to increased PFK enzyme activity, aerobic glycolysis, and proliferation in GBM cells. These findings highlight a novel mechanism underlying the mutual regulation that occurs between PFKP and VEGF for promoting GBM tumor growth and also suggest that targeting the PFKP/VEGF regulatory loop might show therapeutic potential for treating GBM patients.

The pro-invasive factor COL6A2 serves as a novel prognostic marker of glioma

Background

Glioma is an incurable malignant lesion with poor outcome characterized by easy recurrence after surgery with or without radiotherapy and chemotherapy. Studies have shown that COL6A2 is closely related to the tumorigenesis and development of a variety of tumors. However, the role of COL6A2 in glioma and the relationship between COL6A2 and tumor infiltrating immune cells remain unclear.

Methods

Western blot, real-time PCR, a tissue microarray and immunohistochemistry were applied to detect COL6A2 mRNA and protein amounts in glioma, and all experiments were repeated three times. A tissue microarray of glioma samples was used for prognostic analysis. Detection of COL6A2 co-expression with immune genes using immunohistochemical methods, and tumor modeling using nude mice for prevention and treatment studies. Based on the mRNA expression of COL6A2, patients with glioma in TCGA were divided into the low and high COL6A2 expression groups, and GO and KEGG pathway analyses were performed. A PPI network was constructed using STRING, and the associations of COL6A2 with tumor-infiltrating immune cells and immune genes were analyzed in the CIBERSORT and TISIDB databases. COL6A2 mRNA and protein amounts were increased in glioma.

Results

Multiple-database and tissue microarray analyses showed that COL6A2 expression in glioma was associated with poor prognosis, Tissue microarray showed that COL6A2 was the highest expressed in WHO IV and significantly higher in TCGA-GBM than in TCGA-LGG. Immunohistochemistry can well demonstrate the co-expression of COL6A2 with immune genes in a tumor model established in nude mice, showing that interference with COL6A2 expression may have an inhibitory effect on tumors. The mRNA expression of COL6A2 was involved in 22 KEGG pathways, and GSEA analysis showed that 28 and 57 gene sets were significantly enriched at nominal p values <0.01 and <0.05, respectively, protein network revealed a tight interaction between COL6A2 and SPARC. The CIBERSORT database indicated that COL6A2 was correlated with 15 types of tumor-infiltrating immune cells, including M2 macrophages, CD8 T cells, neutrophils, gamma delta T cells, activated CD4 memory T cells, follicular helper T cells, M0 macrophages, M1 macrophages, regulatory T cells (Tregs), activated NK cells, eosinophils, activated mast cells, monocytes, activated dendritic cells, and resting CD4 memory T cells. The TISIDB database indicated that COL6A2 was significantly correlated with lymphocytes such as regulatory T cell, Type 17 T helper cell, Type 1 T helper cell, and immunomodulatory genes. In addition, COL6A2-related immune regulatory genes show that most immune regulatorygenes have prognostic value for glioma, and high-risk immune genes are notconducive to the survival of glioma patients.

Conclusions

COL6A2-related immune regulatory genes show that most immune regulatory genes have prognostic value for glioma, and high-risk immune genes are not conducive to the survival of glioma patients. COL6A2 may be a novel potential prognostic biomarker of glioma and associated with tumor-infiltrating immune cells in the tumor microenvironment, and interference with COL6A2 expression can inhibit tumor growth, which suggests COL6A2 as a potential target for future treatment.

Synergistic Anticancer Effect of a Combination of Berbamine and Arcyriaflavin A against Glioblastoma Stem-like Cells

Glioblastoma multiforme (GBM) is the most aggressive form of brain tumor. Relapse is frequent and rapid due to glioblastoma stem-like cells (GSCs) that induce tumor initiation, drug resistance, high cancer invasion, immune evasion, and recurrence. Therefore, suppression of GSCs is a powerful therapeutic approach for GBM treatment. Natural compounds berbamine and arcyriaflavin A (ArcA) are known to possess anticancer activity by targeting calcium/calmodulin-dependent protein kinase II gamma (CaMKIIγ) and cyclin-dependent kinase 4 (CDK4), respectively. In this study, we evaluated the effects of concurrent treatment with both compounds on GSCs. Combined treatment with berbamine and ArcA synergistically inhibited cell viability and tumorsphere formation in U87MG- and C6-drived GSCs. Furthermore, simultaneous administration of both compounds potently inhibited tumor growth in a U87MG GSC-grafted chick embryo chorioallantoic membrane (CAM) model. Notably, the synergistic anticancer effect of berbamine and ArcA on GSC growth is associated with the promotion of reactive oxygen species (ROS)- and calcium-dependent apoptosis via strong activation of the p53-mediated caspase cascade. Moreover, co-treatment with both compounds significantly reduced the expression levels of key GSC markers, including CD133, integrin α6, aldehyde dehydrogenase 1A1 (ALDH1A1), Nanog, Sox2, and Oct4. The combined effect of berbamine and ArcA on GSC growth also resulted in downregulation of cell cycle regulatory proteins, such as cyclins and CDKs, by potent inactivation of the CaMKIIγ-mediated STAT3/AKT/ERK1/2 signaling pathway. In addition, a genetic knockdown study using small interfering RNAs (siRNAs) targeting either CaMKIIγ or CDK4 demonstrated that the synergistic anticancer effect of the two compounds on GSCs resulted from dual inhibition of CaMKIIγ and CDK4. Collectively, our findings suggest that a novel combination therapy involving berbamine and ArcA could effectively eradicate GSCs.

Serine and glycine metabolism-related gene expression signature stratifies immune profiles of brain gliomas, and predicts prognosis and responses to immunotherapy

Glioma is one of the most lethal cancers and causes more than 200,000 deaths every year. Immunotherapy was an inspiring therapy for multiple cancers but failed in glioma treatment. The importance of serine and glycine and their metabolism has been well-recognized in the physiology of immune cells and microenvironment in multiple cancers. However, their correlation with prognosis, immune cells, and immune microenvironment of glioma remains unclear. In this study, we investigated the relationships between the expression pattern of serine and glycine metabolism-related genes (SGMGs) and clinicopathological features, prognosis, and tumor microenvironment in glioma based on comprehensive analyses of multiple public datasets and our cohort. According to the expression of SGMGs, we conducted the consensus clustering analysis to stratify all patients into four clusters with remarkably distinctive clinicopathological features, prognosis, immune cell infiltration, and immune microenvironment. Subsequently, a serine and glycine metabolism-related genes signature (SGMRS) was constructed based on five critical SGMGs in glioma to stratify patients into SGMRS high- and low-risk groups and tested for its prognostic value. Higher SGMRS expressed genes associated with the synthesis of serine and glycine at higher levels and manifested poorer prognosis. Besides, we confirmed that SGMRS was an independent prognostic factor and constructed nomograms with satisfactory prognosis prediction performance based on SGMRS and other factors. Analyzing the relationship between SGMRS and immune landscape, we found that higher SGMRS correlated with 'hotter' immunological phenotype and more immune cell infiltration. Furthermore, the expression levels of multiple immunotherapy-related targets, including PD-1, PD-L1, and B7-H3, were positively correlated with SGMRS, which was validated by the better predicted response to immune checkpoint inhibitors. In conclusion, our study explored the relationships between the expression pattern of SGMGs and tumor features and created novel models to predict the prognosis of glioma patients. The correlation of SGMRS with immune cells and microenvironment in gliomas suggested an essential role of serine and glycine metabolism in reforming immune cells and microenvironment. Finally, the results of our study endorsed the potential application of SGMRS to guide the selection of immunotherapy for gliomas.

A bibliometric and visualization-based analysis of temozolomide research hotspots and frontier evolution

The literature related to TMZ research in the Web of Science (WOS) database was analyzed using bibliometrics and visualization by Citespace and VOSviewer.The publication status (number of publications, institutions, and frequency of citations), collaborations, and research focus was analyzed to clarify the current situation of TMZ research. And the recent research on TMZ provides a detailed summary. Based on objective data analysis, this study provides a complete analysis portraying the progression of historical milestones in TMZ development and future research directions from various TMZ research domains.

Initiatives Toward Clinical Boron Neutron Capture Therapy in Japan

Boron neutron capture therapy (BNCT) has been performed at nuclear research reactors for many years. The development of accelerators for BNCT resulted in a paradigm shift from research to real clinical applications. In Japan, BNCT was approved as a clinical therapy covered by the National Health Insurance in 2020. In this article, the status of BNCT in Japan is briefly introduced.

Purine metabolism-related gene expression signature predicts survival outcome and indicates immune microenvironment profile of gliomas

Glioma is the most common malignant tumor in the central nervous system. The impact of metabolism on cancer development and the immune microenvironment landscape has recently gained broad attention. Purines are involved in multiple metabolic pathways. It has been proved that purine metabolism could regulate malignant biological behaviors and response to immune checkpoint inhibitors in multiple cancers. However, the relationship of purine metabolism with clinicopathological features and the immune landscape of glioma remains unclear. In this study, we explored the relationships between the expression of purine metabolism-related genes (PuMGs) and tumor features, including prognosis and microenvironment of glioma, based on analyses of 1,523 tumors from 4 public databases and our cohort. Consensus clustering based on 136 PuMGs classified the glioma patients into two clusters with significantly distinguished prognosis and immune microenvironment landscapes. Increased immune infiltration was associated with more aggressive gliomas. The prognostic Purine Metabolism-Related Genes Risk Signature (PuMRS), based on 11 critical PuMGs, stratified the patients into PuMRS low- and high-risk groups in the training set and was validated by validation sets from multiple cohorts. The high-risk group presented with significantly shorter overall survival, and further survival analysis demonstrated that the PuMRS was an independent prognostic factor in glioma. The nomogram combining PuMRS and other clinicopathological factors showed satisfactory accuracy in predicting glioma patients’ prognosis. Furthermore, analyses of the tumor immune microenvironment suggested that higher PuMRS was correlated with increased immune cell infiltration and gene expression signatures of “hotˮ tumors. Gliomas in the PuMRS high-risk group presented a higher expression level of multiple immune checkpoints, including PD-1 and PD-L1, and a better-predicted therapy response to immune checkpoint inhibitors. In conclusion, our study elucidated the relationship between the expression level of PuMGs and the aggressiveness of gliomas. Our study also endorsed the application of PuMRS to construct a new robust model for the prognosis evaluation of glioma patients. The correlations between the profiles of PuMGs expression and tumor immune microenvironment potentially provided guidance for immunotherapy in glioma.

Bevacizumab beyond Progression for Newly Diagnosed Glioblastoma (BIOMARK): Phase II Safety, Efficacy and Biomarker Study

We evaluated the efficacy and safety of bevacizumab beyond progression (BBP) in Japanese patients with newly diagnosed glioblastoma and explored predictors of response to bevacizumab. This phase II study evaluated a protocol-defined primary therapy by radiotherapy with concurrent and adjuvant temozolomide plus bevacizumab, followed by bevacizumab monotherapy, and secondary therapy (BBP: bevacizumab upon progression). Ninety patients received the protocol-defined primary therapy (BBP group, n = 25). Median overall survival (mOS) and median progression-free survival (mPFS) were 25.0 and 14.9 months, respectively. In the BBP group, in which O⁶-methylguanine-DNA methyltransferase (MGMT)-unmethylated tumors predominated, mOS and mPFS were 5.8 and 1.9 months from BBP initiation and 16.8 and 11.4 months from the initial diagnosis, respectively. The primary endpoint, the 2-year survival rate of the BBP group, was 27.0% and was unmet. No unexpected adverse events occurred. Expression profiling using RNA sequencing identified that Cluster 2, which was enriched with the genes involved in macrophage or microglia activation, was associated with longer OS and PFS independent of the MGMT methylation status. Cluster 2 was identified as a significantly favorable independent predictor for PFS, along with younger age and methylated MGMT. The novel expression classifier may predict the prognosis of glioblastoma patients treated with bevacizumab.

Spatial analysis of the glioblastoma proteome reveals specific molecular signatures and markers of survival

Molecular heterogeneity is a key feature of glioblastoma that impedes patient stratification and leads to large discrepancies in mean patient survival. Here, we analyze a cohort of 96 glioblastoma patients with survival ranging from a few months to over 4 years. 46 tumors are analyzed by mass spectrometry-based spatially-resolved proteomics guided by mass spectrometry imaging. Integration of protein expression and clinical information highlights three molecular groups associated with immune, neurogenesis, and tumorigenesis signatures with high intra-tumoral heterogeneity. Furthermore, a set of proteins originating from reference and alternative ORFs is found to be statistically significant based on patient survival times. Among these proteins, a 5-protein signature is associated with survival. The expression of these 5 proteins is validated by immunofluorescence on an additional cohort of 50 patients. Overall, our work characterizes distinct molecular regions within glioblastoma tissues based on protein expression, which may help guide glioblastoma prognosis and improve current glioblastoma classification.

Ablation efficacy of 5-aminolevulinic acid-mediated photodynamic therapy on human glioma stem cells

BACKGROUND

Cancer cells with stem cell-like features are generally more resistant to chemotherapy and radiotherapy than differentiated tumor cells. Thus, these cells tend to increase the propensity for tumor recurrence and metastasis. This study investigated the efficacy of 5-aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) in destructing glioma stem cells (GSCs), including the mesenchymal subtype (MES-GSCs) demonstrated to have the lowest radio- and chemosensitivity.

METHODS

Five high-grade glioma (HGG) GSC lines and derived differentiated glioma cell (DGC) lines were examined for protoporphyrin-IX (PpIX) expression using fluorescence-activated cell sorting (FACS) and then assessed for ALA-PDT sensitivity using cell viability assays. MES-GSCs surviving ALA-PDT were then isolated and evaluated for stem cell and mesenchymal marker expression levels (CD44, ALDH1A3, KLF4, nestin) by qRT-PCR. The ability of these surviving cells to form tumors was then examined using colony forming and by xenograft tumor assays in athymic mice. Finally, the relationship between PpIX expression level (high versus low) and ALA-PDT sensitivity was examined by FACS and colony forming assays.

RESULTS

ALA-PDT was effective against all GSC lines including MES-GSCs. MES-GSC lines exhibited higher PpIX expression than derived DGCs. Surviving MES-GSCs demonstrated lower stem cell marker expression and tumor forming potential than naive MES-GSCs. Higher PpIX production capacity by MES-GSCs was associated with greater colony forming ability, and ALA-PDT was more effective against MES-GSCs with greater PpIX accumulation.

CONCLUSION

ALA-PDT may be clinically effective against HGG by targeting GSCs, including MES-GSCs.

Surgical cytoreduction of deep-seated high-grade glioma through tubular retractor

OBJECTIVE

Maximal safe resection is the goal of surgical treatment for high-grade glioma (HGG). Deep-seated hemispheric gliomas present a surgical challenge due to safety concerns and previously were often considered inoperable. The authors hypothesized that use of tubular retractors would allow resection of deep-seated gliomas with an acceptable safety profile. The purpose of this study was to describe surgical outcomes and survival data after resection of deep-seated HGG with stereotactically placed tubular retractors, as well as to discuss the technical advances that enable such procedures.

METHODS

This is a retrospective review of 20 consecutive patients who underwent 22 resections of deep-seated hemispheric HGG with the Viewsite Brain Access System by a single surgeon. Patient demographics, survival, tumor characteristics, extent of resection (EOR), and neurological outcomes were recorded. Cannulation trajectories and planned resection volumes depended on the relative location of white matter tracts extracted from diffusion tractography. The surgical plans were designed on the Brainlab system and preoperatively visualized on the Surgical Theater virtual reality SNAP platform. Volumetric assessment of EOR was obtained on the Brainlab platform and confirmed by a board-certified neuroradiologist.

RESULTS

Twenty adult patients (18 with IDH-wild-type glioblastomas and 2 with IDH-mutant grade IV astrocytomas) and 22 surgeries were included in the study. The cohort included both newly diagnosed (n = 17; 77%) and recurrent (n = 5; 23%) tumors. Most tumors (64%) abutted the ventricular system. The average preoperative and postoperative tumor volumes measured 33.1 ± 5.3 cm3 and 15.2 ± 5.1 cm3, respectively. The median EOR was 93%. Surgical complications included 2 patients (10%) who developed entrapment of the temporal horn, necessitating placement of a ventriculoperitoneal shunt; 1 patient (5%) who suffered a wound infection and pulmonary embolus; and 1 patient (5%) who developed pneumonia. In 2 cases (9%) patients developed new permanent visual field deficits, and in 5 cases (23%) patients experienced worsening of preoperative deficits. Preoperative neurological or cognitive deficits remained the same in 9 cases (41%) and improved in 7 (32%). The median overall survival was 14.4 months in all patients (n = 20) and in the newly diagnosed IDH-wild-type glioblastoma group (n = 16).

CONCLUSIONS

Deep-seated HGGs, which are surgically challenging and frequently considered inoperable, are amenable to resection through tubular retractors, with an acceptable safety profile. Such cytoreductive surgery may allow these patients to experience an overall survival comparable to those with more superficial tumors.

Prodigiosin inhibits the proliferation of glioblastoma by regulating the KIAA1524/PP2A signaling pathway

Prodigiosin (PG), a member of a family of natural red pigments produced by a variety of bacteria, was first discovered in Serratia marcescens. PG has been reported to have an apoptosis-inducing effect in many cancers, such as lymphoma, colon cancer and nasopharyngeal carcinoma. For this study, we used three glioblastoma (GBM) cell lines (LN229, U251 and A172) to explore the effect of prodigiosin on GBM cells. A CCK8 assay was used to evaluate cell viability. We determinedthe cell cycle distribution by flow cytometry and measured proliferation by an EdU incorporation assay. The expression of different molecules was investigated by western blotting and RT-PCR. We further confirmed our results by plasmid transfection and lentiviral transduction. The LN229 xenograft model was used to study the effect of prodigiosin in vivo. We confirmed that prodigiosin played an anticancer role in several GBM cell lines through the KIAA1524/PP2A/Akt signalling pathway. Prodigiosin inhibited the protein expression of KIAA1524 by suppressing its transcription, which led to activation of PP2A. Afterward, PP2A inhibited the phosphorylation of Akt, thereby inducing increased expression of p53/p21. Furthermore, it was verified that prodigiosin inhibited the KIAA1524/PP2A/Akt axis in vivo in the LN229 xenograft model. These data improve the understanding of the anticancer effects of prodigiosin and further highlight the potential of prodigiosin for the development of anti-glioma drugs.

Vascular complications in patients with brain tumors

PURPOSE OF REVIEW

Venous thromboembolism (VTE) and other vascular events are common in patients with brain tumors, but their optimal management is not firmly established, in large part due to the competing risk of intracranial hemorrhage (ICH) in this population.

RECENT FINDINGS

There is conflicting evidence on whether therapeutic anticoagulation increases the risk of ICH in patients with brain tumors, with several metanalysis and retrospective cohort studies showing an increased risk and others showing no differences. Current guidelines recommend anticoagulating brain tumors patients with VTE with either low-molecular weight heparin (LMWH) or direct oral anticoagulants (DOACs), and several retrospective studies have shown the risk of ICH with DOACs is similar or smaller than with LMWH.

SUMMARY

An increased risk of VTE exists in a variety of brain tumor types. Most patients with brain tumors and VTE should receive therapeutic anticoagulation, and recent retrospective evidence supports the use of both LMWH and DOACs as effective and relatively safe in this setting. Patients with brain tumors are also at increased risk of other vascular tumor- or treatment-related complications whose optimal management is unclear.

Prognosis prediction and tumor immune microenvironment characterization based on tryptophan metabolism-related genes signature in brain glioma

Glioma is the most common malignant tumor in the central nervous system with no significant therapeutic breakthrough in recent years. Most attempts to apply immunotherapy in glioma have failed. Tryptophan and its metabolism can regulate malignant features of cancers and reshape immune microenvironment of tumors. However, the role of tryptophan metabolism in glioma remains unclear. In current study, we explored the relationships between the expression pattern of tryptophan metabolism-related genes (TrMGs) and tumor characteristics, including prognosis and tumor microenvironment of gliomas through analyzing 1,523 patients' samples from multiple public databases and our own cohort. Based on expression of TrMGs, K-means clustering analysis stratified all glioma patients into two clusters with significantly different TrMG expression patterns, clinicopathological features and immune microenvironment. Furthermore, we constructed a tryptophan metabolism-related genes signature (TrMRS) based on seven essential TrMGs to classify the patients into TrMRS low- and high-risk groups and validated the prognostic value of the TrMRS in multiple cohorts. Higher TrMRS represented for potentially more active tryptophan catabolism, which could subsequently lead to less tryptophan in tumor. The TrMRS high-risk group presented with shorter overall survival, and further analysis confirmed TrMRS as an independent prognostic factor in gliomas. The nomograms uniting TrMRS with other prognostic factors manifested with satisfactory efficacy in predicting the prognosis of glioma patients. Additionally, analyses of tumor immune landscapes demonstrated that higher TrMRS was correlated with more immune cell infiltration and "hot" immunological phenotype. TrMRS was also demonstrated to be positively correlated with the expression of multiple immunotherapy targets, including PD1 and PD-L1. Finally, the TrMRS high-risk group manifested better predicted response to immune checkpoint inhibitors. In conclusion, our study illustrated the relationships between expression pattern of TrMGs and characteristics of gliomas, and presented a novel model based on TrMRS for prognosis prediction in glioma patients. The association between TrMRS and tumor immune microenvironment of gliomas indicated an important role of tryptophan and its metabolism in reshaping immune landscape and the potential ability to guide the application of immunotherapy for gliomas.

Glioma stem cells and neural stem cells respond differently to BMP4 signaling

Malignant glioma is a highly heterogeneous and invasive primary brain tumor characterized by high recurrence rates, resistance to combined therapy, and dismal prognosis. Glioma stem cells (GSCs) are likely responsible for tumor progression, resistance to therapy, recurrence, and poor prognosis owing to their high self-renewal and tumorigenic potential. As a family member of BMP signaling, bone morphogenetic protein4 (BMP4) has been reported to induce the differentiation of GSCs and neural stem cells (NSCs). However, the molecular mechanisms underlying the BMP4-mediated effects in these two cell types are unclear. In this study, we treated hGSCs and hNSCs with BMP4 and compared the phenotypic and transcriptional changes between these two cell types. Phenotypically, we found that the growth of hGSCs was greatly inhibited by BMP4, but the same treatment only increased the cell size of hNSCs. While the RNA sequencing results showed that BMP4 treatment evoked significantly transcriptional changes in both hGSCs and hNSCs, the profiles of differentially expressed genes were distinct between the two groups. A gene set that specifically targeted the proliferation and differentiation of hGSCs but not hNSCs was enriched and then validated in hGSC culture. Our results suggested that hGSCs and hNSCs responded differently to BMP4 stimulation. Understanding and investigating different responses between hGSCs and hNSCs will benefit finding partner factors working together with BMP4 to further suppress GSCs proliferation and stemness without disturbing NSCs.

Multiparametric Longitudinal Profiling of RCAS-tva-Induced PDGFB-Driven Experimental Glioma

Glioblastomas are incurable primary brain tumors harboring a heterogeneous landscape of genetic and metabolic alterations. Longitudinal imaging by MRI and [18F]FET-PET measurements enable us to visualize the features of evolving tumors in a dynamic manner. Yet, close-meshed longitudinal imaging time points for characterizing temporal and spatial metabolic alterations during tumor evolution in patients is not feasible because patients usually present with already established tumors. The replication-competent avian sarcoma-leukosis virus (RCAS)/tumor virus receptor-A (tva) system is a powerful preclinical glioma model offering a high grade of spatial and temporal control of somatic gene delivery in vivo. Consequently, here, we aimed at using MRI and [18F]FET-PET to identify typical neuroimaging characteristics of the platelet-derived growth factor B (PDGFB)-driven glioma model using the RCAS-tva system. Our study showed that this preclinical glioma model displays MRI and [18F]FET-PET features that highly resemble the corresponding established human disease, emphasizing the high translational relevance of this experimental model. Furthermore, our investigations unravel exponential growth dynamics and a model-specific tumor microenvironment, as assessed by histology and immunochemistry. Taken together, our study provides further insights into this preclinical model and advocates for the imaging-stratified design of preclinical therapeutic interventions.

Balancing Risk and Efficiency in Drug Development for Rare and Challenging Tumors: A New Paradigm for Glioma

The process of developing cancer therapies is well established and has enabled the incorporation of many new drugs and classes of agents into the standard of care for common cancers. Clinical drug development is fundamentally different for rare and difficult-to-treat solid tumors, such as glioma or pancreatic cancer. The failure to develop effective new agents for the latter diseases has discouraged the development of therapeutics for these cancers. Using glioma as an example, we describe a process toward obtaining more reliable early-stage signals of drug activity and a process toward translating those signals into clinical benefits with more efficient late-stage development. If linked together, these processes should increase the likelihood of benefit in late-stage settings at a lower cost and encourage more drug development for patients with rare and difficult-to-treat cancers.

Next-Generation Sequencing Comparative Analysis of DNA Mutations between Blood-Derived Extracellular Vesicles and Matched Cancer Tissue in Patients with Grade 4 Glioblastoma

The biological heterogeneity of glioblastoma, IDH-wildtype (GBM, CNS WHO grade 4), the most aggressive type of brain cancer, is a critical hallmark, caused by changes in the genomic mutational asset and influencing clinical progression over time. The understanding and monitoring of the mutational profile is important not only to reveal novel therapeutic targets in this set of patients, but also to ameliorate the clinical stratification of subjects and the prognostic significance. As neurosurgery represents the primary technique to manage GBM, it is of utmost importance to optimize alternative and less invasive methods to monitor the dynamic mutation profile of these patients. Extracellular vesicles (EVs) are included in the liquid biopsy analysis and have emerged as the biological mirror of escaping and surviving mechanisms by many tumors, including glioblastoma. Very few studies have investigated the technical feasibility to detect and analyze the genomic profile by Next-Generation Sequencing (UMI system) in circulating EVs of patients with grade IV glioblastoma. Here, we attempted to characterize and to compare the corresponding matched tissue samples and potential variants with pathogenic significance of the DNA contained in peripheral-blood-derived EVs. The NGS analysis has revealed that patients with grade IV glioblastoma exhibited lesser DNA content in EVs than controls and that, both in EVs and matched cancer tissues, the NF1 gene was consistently mutated in all patients, with the c.2568C>G as the most common pathogenic variant expressed. This study supports the clinical utility of circulating EVs in glioblastoma as an eligible tool for personalized medicine.

Tumor Treating Fields (TTFields) therapy vs physicians' choice standard-of-care treatment in patients with recurrent glioblastoma: a post-approval registry study (EF-19)

PURPOSE

Tumor Treating Fields (TTFields) therapy, a noninvasive, anti-mitotic treatment modality, is approved for recurrent glioblastoma (rGBM) and newly diagnosed GBM based on phase III, EF-11 (NCT00379470) and EF-14 (NCT00916409) studies, respectively. The EF-19 study aimed to evaluate efficacy and safety of TTFields monotherapy (200 kHz) vs physicians' choice standard of care (PC-SOC; EF-11 historical control group) in rGBM.

METHODS

A prospective, post-marketing registry study of adults with supratentorial rGBM treated with TTFields therapy was conducted. Primary endpoint was overall survival (OS; intent-to-treat [ITT] population) and secondary endpoint was OS per-protocol (PP). Subgroup and toxicity analyses were conducted.

RESULTS

Median OS (ITT population) was comparable with TTFields monotherapy vs PC-SOC (7.4 vs 6.4 months, log-rank test P = 0.053; Cox test hazard ratio [HR] [95% CI], 0.66 [0.47-0.92], P = 0.016). The upper-bound HR (95% CI) was lower than pre-defined noninferiority (1.375 threshold). In the PP population, median OS was significantly longer for TTFields monotherapy vs PC-SOC (8.1 vs 6.4 months; log-rank test P = 0.017; Cox test HR [95% CI], 0.60 [0.42-0.85], P = 0.004). TTFields therapy showed increased benefit with extended use (≥ 18 h/day [averaged over 28 days]). TTFields therapy-related adverse events (AEs) by body system were lower vs PC-SOC: mainly mild-to-moderate skin AEs.

CONCLUSION

In the real-world setting, TTFields monotherapy showed comparable (ITT population) and superior (PP population) OS vs PC-SOC in rGBM. In line with previous results, TTFields therapy showed a favorable safety profile vs chemotherapy, without new safety signals/systemic effects.

TRIAL REGISTRATION

NCT01756729, registered December 20, 2012.

Music improves the therapeutic effects of bevacizumab in rats with glioblastoma: Modulation of drug distribution to the brain

Background

The development of new methods for modulation of drug distribution across to the brain is a crucial step in the effective therapies for glioblastoma (GBM). In our previous work, we discovered the phenomenon of music-induced opening of the blood-brain barrier (OBBB) in healthy rodents. In this pilot study on rats, we clearly demonstrate that music-induced BBB opening improves the therapeutic effects of bevacizumab (BZM) in rats with GBM via increasing BZM distribution to the brain along the cerebral vessels.

Methods

The experiments were performed on Wistar male rats (200–250 g, n=161) using transfected C6-TagRFP cell line and the loud rock music for OBBB. The OBBB was assessed by spectrofluorometric assay of Evans Blue (EB) extravasation and confocal imaging of fluorescent BZM (fBZM) delivery into the brain. Additionally, distribution of fBZM and Omniscan in the brain was studied using fluorescent and magnetic resonance imaging (MRI), respectively. To analyze the therapeutic effects of BZM on the GBM growth in rats without and with OBBB, the GBM volume (MRI scans), as well as immunohistochemistry assay of proliferation (Ki67 marker) and apoptosis (Bax marker) in the GBM cells were studied. The Mann–Whitney–Wilcoxon test was used for all analysis, the significance level was p < 0.05, n=7 in each group.

Results

Our finding clearly demonstrates that music-induced OBBB increases the delivery of EB into the brain tissues and the extravasation of BZM into the brain around the cerebral vessels of rats with GBM. Music significantly increases distribution of tracers (fBZM and Omniscan) in the rat brain through the pathways of brain drainage system (perivascular and lymphatic), which are an important route of drug delivery into the brain. The music-induced OBBB improves the suppressive effects of BZM on the GBM volume and the cellular mechanisms of tumor progression that was accompanied by higher survival among rats in the GBM+BZM+Music group vs. other groups.

Conclusion

We hypothesized that music improves the therapeutic effects of BZM via OBBB in the normal cerebral vessels and lymphatic drainage of the brain tissues. This contributes better distribution of BZM in the brain fluids and among the normal cerebral vessels, which are used by GBM for invasion and co-opt existing vessels as a satellite tumor form. These results open the new perspectives for an improvement of therapeutic effects of BZM via the music-induced OBBB for BZM in the normal cerebral vessels, which are used by GBM for migration and progression.

Targeting tumor-associated macrophages for the immunotherapy of glioblastoma: Navigating the clinical and translational landscape

Tumor-associated macrophages (TAMs) can directly clear tumor cells and enhance the phagocytic ability of immune cells. An abundance of TAMs at the site of the glioblastoma tumor indicates that TAM-targeting immunotherapy could represent a potential form of treatment for this aggressive cancer. Herein, we discuss: i) the dynamic role of TAMs in glioblastoma; ii) describe the formation of the immunosuppressive tumor microenvironment; iii) summarize the latest clinical trial data that reveal how TAM function can be regulated in favor tumor eradication; and lastly, iv) evaluate the implications of existing and novel translational approaches for treating glioblastoma in clinical practice.

Cancer cell autophagy, reprogrammed macrophages, and remodeled vasculature in glioblastoma triggers tumor immunity

Glioblastoma (GBM) is poorly responsive to therapy and invariably lethal. One conceivable strategy to circumvent this intractability is to co-target distinctive mechanistic components of the disease, aiming to concomitantly disrupt multiple capabilities required for tumor progression and therapeutic resistance. We assessed this concept by combining vascular endothelial growth factor (VEGF) pathway inhibitors that remodel the tumor vasculature with the tricyclic antidepressant imipramine, which enhances autophagy in GBM cancer cells and unexpectedly reprograms immunosuppressive tumor-associated macrophages via inhibition of histamine receptor signaling to become immunostimulatory. While neither drug is efficacious as monotherapy, the combination of imipramine with VEGF pathway inhibitors orchestrates the infiltration and activation of CD8 and CD4 T cells, producing significant therapeutic benefit in several GBM mouse models. Inclusion up front of immune-checkpoint blockade with anti-programmed death-ligand 1 (PD-L1) in eventually relapsing tumors markedly extends survival benefit. The results illustrate the potential of mechanism-guided therapeutic co-targeting of disparate biological vulnerabilities in the tumor microenvironment.

Small-molecule inhibitors, immune checkpoint inhibitors, and more: FDA-approved novel therapeutic drugs for solid tumors from 1991 to 2021

The United States Food and Drug Administration (US FDA) has always been a forerunner in drug evaluation and supervision. Over the past 31 years, 1050 drugs (excluding vaccines, cell-based therapies, and gene therapy products) have been approved as new molecular entities (NMEs) or biologics license applications (BLAs). A total of 228 of these 1050 drugs were identified as cancer therapeutics or cancer-related drugs, and 120 of them were classified as therapeutic drugs for solid tumors according to their initial indications. These drugs have evolved from small molecules with broad-spectrum antitumor properties in the early stage to monoclonal antibodies (mAbs) and antibody‒drug conjugates (ADCs) with a more precise targeting effect during the most recent decade. These drugs have extended indications for other malignancies, constituting a cancer treatment system for monotherapy or combined therapy. However, the available targets are still mainly limited to receptor tyrosine kinases (RTKs), restricting the development of antitumor drugs. In this review, these 120 drugs are summarized and classified according to the initial indications, characteristics, or functions. Additionally, RTK-targeted therapies and immune checkpoint-based immunotherapies are also discussed. Our analysis of existing challenges and potential opportunities in drug development may advance solid tumor treatment in the future.

Prognostic value of cuproptosis-related genes signature and its impact on the reshaped immune microenvironment of glioma

Glioma is the most prevalent malignancy in the central nervous system. The impact of ion-induced cell death on malignant tumors’ development and immune microenvironment has attracted broad attention in recent years. Cuproptosis is a novel copper-dependent mechanism that could potentially regulate tumor cell death by targeting mitochondria respiration. However, the role of cuproptosis in gliomas remains unclear. In the present study, we investigated the relationships between the expression of cuproptosis-related genes (CRGs) and tumor characteristics, including prognosis and microenvironment of glioma, by analyzing multiple public databases and our cohort. Consensus clustering based on the expression of twelve CRGs stratified the glioma patients into three subgroups with significantly different prognosis and immune microenvironment landscapes. Reduced immune infiltration was associated with the less aggressive CRG cluster. A prognostic CRGs risk signature (CRGRS), based on eight critical CRGs, classified the patients into low- and high-risk groups in the training set and was endorsed by validation sets from multiple cohorts. The high-risk group manifested a shorter overall survival, and further survival analysis demonstrated that the CRGRS was an independent prognostic factor. The nomogram combining CRGRS and other clinicopathological factors exhibited good accuracy in predicting the prognosis of glioma patients. Moreover, analyses of tumor immune microenvironment indicated that higher CRGRS was correlated with increased immune cell infiltration but diminished immune function. Gliomas in the high-risk group exhibited higher expression of multiple immune checkpoints, including PD-1 and PD-L1, and a better predicted therapy response to immune checkpoint inhibitors. In conclusion, our study elucidated the connections between CRGs expression and the aggressiveness of gliomas, and the application of CRGRS derived a new robust model for prognosis evaluation of glioma patients. The correlations between the profiles of CRGs expression and immune tumor microenvironment illuminated prospects and potential indications of immunotherapy for glioma.

The design and evaluation of hybrid controlled trials that leverage external data and randomization

Patient-level data from completed clinical studies or electronic health records can be used in the design and analysis of clinical trials. However, these external data can bias the evaluation of the experimental treatment when the statistical design does not appropriately account for potential confounders. In this work, we introduce a hybrid clinical trial design that combines the use of external control datasets and randomization to experimental and control arms, with the aim of producing efficient inference on the experimental treatment effects. Our analysis of the hybrid trial design includes scenarios where the distributions of measured and unmeasured prognostic patient characteristics differ across studies. Using simulations and datasets from clinical studies in extensive-stage small cell lung cancer and glioblastoma, we illustrate the potential advantages of hybrid trial designs compared to externally controlled trials and randomized trial designs.

Patient-level external control data from prior clinical studies or electronic health records can be used in the design and analysis of clinical trials. Here the authors report a hybrid trial design combining the use of external control data and randomization to test experimental treatments, using small cell lung cancer and glioblastoma datasets as examples.

Clinical, Therapeutic, and Prognostic Experience in Patients With Glioblastoma

BACKGROUND

Glioblastoma (GB) represents the most aggressive type of glioma with a poor prognosis despite the therapies used. As of today, data availability for therapeutic and prognosis experiences is limited. The cornerstone for this study is to create a framework overview of Mexico´s experience throughout 17 years of research.

METHODS

Retrospective analysis from 2000 to 2017 including patients with a histological diagnosis of GB was performed. Data were collected from the ABC Medical Center and the Neurology and Neurosurgery National Institute.

RESULTS

One hundred and thirty-seven patients were included with a mean age of 54 years. Histological diagnosis was made in all patients, of which 58.1% had a total resection, 31.6% had a partial resection, and 10.3% of them underwent biopsy. In all cases, patients received treatment under the following conditions: 10 patients were treated exclusively with stereotactic radiotherapy (RT). In 55 patients, a combination of RT and TMZ was used, the other 40 patients received RT plus CBP. Eighteen patients RT added to nitrosourea medication and lastly, 14 patients received a combination of RT/TMZ and Bevacizumab, a monoclonal antibody that inhibits the formation of blood vessels (BVZ). The progression-free survival (PFS) and overall survival (OS) were higher in the RT/TMZ/BVZ group (16.5 to 22.9 months) and the RT/TMZ group (11 to 17 months), the prognostic parameters included: Isocitrate dehydrogenase 1 mutation (IDH1), usage of BVZ and TMZ in the PLS and OS, considering as well, age range (<70 years) as a favorable prognostic factor.

CONCLUSIONS

GB represents the most frequent intracranial neoplasia. Combined fractionated stereotactic RT added to Temozolomide and Bevacizumab received in our population reports favorable and superior results compared to the ones described in the literature. Further studies are necessary to know the biological behavior of our population.

Hypoxia signaling: Challenges and opportunities for cancer therapy

Hypoxia is arguably the first recognized cancer microenvironment hallmark and affects virtually all cellular populations present in tumors. During the past decades the complex adaptive cellular responses to oxygen deprivation have been largely elucidated, raising hope for new anti cancer agents. Despite undeniable preclinical progress, therapeutic targeting of tumor hypoxia is yet to transition from bench to bedside. This review focuses on new pharmacological agents that exploit tumor hypoxia or interfere with hypoxia signaling and discusses strategies to maximize their therapeutic impact.

Oncolytic Viral Therapy for Malignant Glioma and Their Application in Clinical Practice

Glioblastoma is the most common primary malignant brain tumor in adults and outcomes remain poor despite the current standard of care multimodal therapy. Oncolytic virotherapy utilizes engineered viruses to exert an anti-tumor effect via both direct oncolysis and stimulation of an immune response within the tumor microenvironment, turning tumors from "cold" to "hot." This has shown promise as a novel therapeutic modality and attempts to circumvent the challenges associated with traditional treatments. Many oncolytic viruses have been investigated in completed and ongoing clinical trials and while safety has been demonstrated, clinical outcomes have been variable, often with only a subgroup of patients showing a significant response. This review summarizes these studies, addresses relevant technical aspects of oncolytic virus administration, and highlights practical considerations to assist providers in appropriately caring for patients treated with oncolytic virotherapy. Additionally, future directions within the field that may help to maximize efficacy of this modality are discussed.

Updates in IDH-Wildtype Glioblastoma

Glioblastoma is the most aggressive primary brain tumor with a poor prognosis. The 2021 WHO CNS5 classification has further stressed the importance of molecular signatures in diagnosis although therapeutic breakthroughs are still lacking. In this review article, updates on the current and novel therapies in IDH-wildtype GBM will be discussed.

Potassium Ion Channels in Malignant Central Nervous System Cancers

Malignant central nervous system (CNS) cancers are among the most difficult to treat, with low rates of survival and a high likelihood of recurrence. This is primarily due to their location within the CNS, hindering adequate drug delivery and tumour access via surgery. Furthermore, CNS cancer cells are highly plastic, an adaptive property that enables them to bypass targeted treatment strategies and develop drug resistance. Potassium ion channels have long been implicated in the progression of many cancers due to their integral role in several hallmarks of the disease. Here, we will explore this relationship further, with a focus on malignant CNS cancers, including high-grade glioma (HGG). HGG is the most lethal form of primary brain tumour in adults, with the majority of patient mortality attributed to drug-resistant secondary tumours. Hence, targeting proteins that are integral to cellular plasticity could reduce tumour recurrence, improving survival. This review summarises the role of potassium ion channels in malignant CNS cancers, specifically how they contribute to proliferation, invasion, metastasis, angiogenesis, and plasticity. We will also explore how specific modulation of these proteins may provide a novel way to overcome drug resistance and improve patient outcomes.

Effect of anesthesia on the outcome of high-grade glioma patients undergoing supratentorial resection: study protocol for a pragmatic randomized controlled trial

Background

High-grade glioma (HGG) is the most malignant brain tumor with poor outcomes. Whether anesthetic methods have an impact on the outcome of these patients is still unknown. Retrospective study has found no difference between intravenous and inhalation anesthesia on the overall survival (OS) of the HGG patients, however, intravenous anesthesia with propofol might be beneficial in a subgroup of patients with a Karnofsky Performance Status (KPS) Scale less than 80. Further prospective studies are needed to evaluate the results.

Methods

This is a single-centered, randomized controlled, parallel-group trial. Three hundred forty-four patients with primary HGG for tumor resection will be randomly assigned to receive either intravenous anesthesia with propofol or inhalation anesthesia with sevoflurane. The primary outcome is the OS of the patients within 18 months. Secondary outcomes include progression-free survival (PFS), the numerical rating scale (NRS) of pain intensity and sleep quality, the postoperative encephaloedema volume, complications, and the length of hospital stay of the patients.

Discussion

This is a randomized controlled trial to compare the effect of intravenous and inhalation anesthesia maintenance on the outcome of supratentorial HGG patients. The results will contribute to optimizing the anesthesia methods in these patients.

Trial registration

ClinicalTrials.gov NCT02756312. Registered on 29 April 2016 and last updated on 9 Sep 2020

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06716-9.

Use of heparin to rescue immunosuppressive monocyte reprogramming by glioblastoma-derived extracellular vesicles

OBJECTIVE

The profound immunosuppression found in glioblastoma (GBM) patients is a critical barrier to effective immunotherapy. Multiple mechanisms of tumor-mediated immune suppression exist, and the induction of immunosuppressive monocytes such as myeloid-derived suppressor cells (MDSCs) is increasingly appreciated as a key part of this pathology. GBM-derived extracellular vesicles (EVs) can induce the formation of MDSCs. The authors sought to identify the molecular consequences of these interactions in myeloid cells in order to identify potential targets that could pharmacologically disrupt GBM EV-monocyte interaction as a means to ameliorate tumor-mediated immune suppression. Heparin-sulfate proteoglycans (HSPGs) are a general mechanism by which EVs come into association with their target cells, and soluble heparin has been shown to interfere with EV-HSPG interactions. The authors sought to assess the efficacy of heparin treatment for mitigating the effects of GBM EVs on the formation of MDSCs.

METHODS

GBM EVs were collected from patient-derived cell line cultures via staged ultracentrifugation and cocultured with monocytes collected from apheresis cones from healthy blood donors. RNA was isolated from EV-conditioned and unconditioned monocytes after 72 hours of coculture, and RNA-sequencing analysis performed. For the heparin treatment studies, soluble heparin was added at the time of EV-monocyte coculture and flow cytometry analysis was performed 72 hours later. After the initial EV-monocyte coculture period, donor-matched T-cell coculture studies were performed by adding fluorescently labeled and stimulated T cells for 5 days of coculture.

RESULTS

Transcriptomic analysis of GBM EV-treated monocytes demonstrated downregulation of several important immunological and metabolic pathways, with upregulation of the pathways associated with synthesis of cholesterol and HSPG. Heparin treatment inhibited association between GBM EVs and monocytes in a dose-dependent fashion, which resulted in a concomitant reduction in MDSC formation (p < 0.01). The authors further demonstrated that reduced MDSC formation resulted in a partial rescue of immune suppression, as measured by effects on activated donor-matched T cells (p < 0.05).

CONCLUSIONS

The authors demonstrated that GBM EVs induce broad but reproducible reprogramming in monocytes, with enrichment of pathways that may portend an immunosuppressive phenotype. The authors further demonstrated that GBM EV-monocyte interactions are potentially druggable targets for overcoming tumor-mediated immune suppression, with heparin inhibition of EV-monocyte interactions demonstrating proof of principle.

Current and promising treatment strategies in glioma

Gliomas are the most common primary central nervous system tumors; despite recent advances in diagnosis and treatment, glioma patients generally have a poor prognosis. Hence there is a clear need for improved therapeutic options. In recent years, significant effort has been made to investigate immunotherapy and precision oncology approaches. The review covers well-established strategies such as surgery, temozolomide, PCV, and mTOR inhibitors. Furthermore, it summarizes promising therapies: tumor treating fields, immune therapies, tyrosine kinases inhibitors, IDH(Isocitrate dehydrogenase)-targeted approaches, and others. While there are many promising treatment strategies, none fundamentally changed the management of glioma patients. However, we are still awaiting the outcome of ongoing trials, which have the potential to revolutionize the treatment of glioma.

Prognostic significance of therapy-induced myelosuppression in newly diagnosed glioblastoma

BACKGROUND

Myelosuppression is the major toxicity encountered during temozolomide chemoradiotherapy for newly diagnosed glioblastoma.

METHODS

We assessed the association of myelosuppression (neutropenia, thrombocytopenia, anemia, and lymphopenia) during temozolomide chemoradiotherapy alone or in combination with experimental agents with progression-free survival (PFS) or overall survival (OS) in 2073 patients with newly diagnosed glioblastoma enrolled into five clinical trials: CENTRIC, CORE, EORTC 26082, AVAglio, and EORTC 26981. A landmark Cox model was used. For each primary association analysis, a significance level of 1.7% was used.

RESULTS

Lower neutrophil counts at baseline were associated with better PFS (P = .011) and OS (P < .001), independently of steroid intake. Females experienced uniformly more myelotoxicity than males. Lymphopenia during concomitant chemoradiotherapy was associated with OS (P = .009): low-grade (1-2) lymphopenia might be associated with superior OS (HR 0.78, 98.3% CI 0.58-1.06), whereas high-grade (3-4) lymphopenia might be associated with inferior OS (HR 1.08, 98.3% CI 0.75-1.54). There were no associations of altered hematological parameters during concomitant chemoradiotherapy with PFS. During maintenance chemoradiotherapy, no significant association was found between any parameter of myelosuppression and PFS or OS, although exploratory analysis at 5% significance level indicated that either mild-to-moderate (HR 0.76, 95% CI 0.62-0.93) or high-grade lymphopenia (HR 0.65, 95% CI 0.46-0.92) was associated with superior OS (P = .013), but not PFS.

CONCLUSIONS

The association of higher neutrophil counts at baseline with inferior PFS and OS requires further prospective evaluation. The link of therapy-induced lymphopenia to better outcome may guide the design for immunotherapy trials in newly diagnosed glioblastoma.

An Orthotopic Model of Glioblastoma Is Resistant to Radiodynamic Therapy with 5-AminoLevulinic Acid

Simple Summary

Radiosensitization of glioblastoma is a major ambition to increase the survival of this incurable cancer. Before surgery, oral administration of 5-aminolevulinic acid leads to the accumulation of fluorescent protoporphyrin IX, preferentially in the cancer cells rather than in the normal brain. This property is used to optimize the resection of the tumor under fluorescent light. Protoporphyrin IX may also carry radiosensitization activity. To test this hypothesis, we designed a robust murine preclinical model of glioblastoma with tumors implanted into the brain of mice treated by fractionated radiotherapy, as for humans. Despite the specific accumulation of porphyrins in glioblastoma, there was no radiosensitization. We confirmed these results in in vitro 3D patient-derived spheroids. Radiosensitization by molecules such as porphyrins needs more exploration for application in glioblastoma treatment.

Abstract

Radiosensitization of glioblastoma is a major ambition to increase the survival of this incurable cancer. The 5-aminolevulinic acid (5-ALA) is metabolized by the heme biosynthesis pathway. 5-ALA overload leads to the accumulation of the intermediate fluorescent metabolite protoporphyrin IX (PpIX) with a radiosensitization potential, never tested in a relevant model of glioblastoma. We used a patient-derived tumor cell line grafted orthotopically to create a brain tumor model. We evaluated tumor growth and tumor burden after different regimens of encephalic multifractionated radiation therapy with or without 5-ALA. A fractionation scheme of 5 × 2 Gy three times a week resulted in intermediate survival [48–62 days] compared to 0 Gy (15–24 days), 3 × 2 Gy (41–47 days) and, 5 × 3 Gy (73–83 days). Survival was correlated to tumor growth. Tumor growth and survival were similar after 5 × 2 Gy irradiations, regardless of 5-ALA treatment (RT group (53–67 days), RT+5-ALA group (40–74 days), HR = 1.57, p = 0.24). Spheroid growth and survival were diminished by radiotherapy in vitro, unchanged by 5-ALA pre-treatment, confirming the in vivo results. The analysis of two additional stem-like patient-derived cell lines confirmed the absence of radiosensitization by 5-ALA. Our study shows for the first time that in a preclinical tumor model relevant to human glioblastoma, treated as in clinical routine, 5-ALA administration, although leading to important accumulation of PpIX, does not potentiate radiotherapy.

Combination of Ad-SGE-REIC and bevacizumab modulates glioma progression by suppressing tumor invasion and angiogenesis

Reduced expression in immortalized cells/Dickkopf-3 (REIC/Dkk-3) is a tumor suppressor and its overexpression has been shown to exert anti-tumor effects as a therapeutic target gene in many human cancers. Recently, we demonstrated the anti-glioma effects of an adenoviral vector carrying REIC/Dkk-3 with the super gene expression system (Ad-SGE-REIC). Anti-vascular endothelial growth factor treatments such as bevacizumab have demonstrated convincing therapeutic advantage in patients with glioblastoma. However, bevacizumab did not improve overall survival in patients with newly diagnosed glioblastoma. In this study, we examined the effects of Ad-SGE-REIC on glioma treated with bevacizumab. Ad-SGE-REIC treatment resulted in a significant reduction in the number of invasion cells treated with bevacizumab. Western blot analyses revealed the increased expression of several endoplasmic reticulum stress markers in cells treated with both bevacizumab and Ad-SGE-REIC, as well as decreased β-catenin protein levels. In malignant glioma mouse models, overall survival was extended in the combination therapy group. These results suggest that the combination therapy of Ad-SGE-REIC and bevacizumab exerts anti-glioma effects by suppressing the angiogenesis and invasion of tumors. Combined Ad-SGE-REIC and bevacizumab might be a promising strategy for the treatment of malignant glioma.

In silico validation of RNA-Seq results can identify gene fusions with oncogenic potential in glioblastoma

RNA-Sequencing (RNA-Seq) can identify gene fusions in tumors, but not all these fusions have functional consequences. Using multiple data bases, we have performed an in silico analysis of fusions detected by RNA-Seq in tumor samples from 139 newly diagnosed glioblastoma patients to identify in-frame fusions with predictable oncogenic potential. Among 61 samples with fusions, there were 103 different fusions, involving 167 different genes, including 20 known oncogenes or tumor suppressor genes (TSGs), 16 associated with cancer but not oncogenes or TSGs, and 32 not associated with cancer but previously shown to be involved in fusions in gliomas. After selecting in-frame fusions able to produce a protein product and running Oncofuse, we identified 30 fusions with predictable oncogenic potential and classified them into four non-overlapping categories: six previously described in cancer; six involving an oncogene or TSG; four predicted by Oncofuse to have oncogenic potential; and 14 other in-frame fusions. Only 24 patients harbored one or more of these 30 fusions, and only two fusions were present in more than one patient: FGFR3::TACC3 and EGFR::SEPTIN14. This in silico study provides a good starting point for the identification of gene fusions with functional consequences in the pathogenesis or treatment of glioblastoma.

Multimodal targeting of glioma with functionalized nanoparticles

The most common and aggressive primitive intracranial tumor of the central nervous system is the glioma. The blood–brain barrier (BBB) has proven to be a significant obstacle to the effective treatment of glioma. To effectively treat glioma, different ways have been used to cross the BBB to deliver drugs to the brain. Drug delivery through nanocarriers proves to be an effective and non-invasive technique for the treatment of glioma and has great potential in the treatment of glioma. In this review, we will provide an overview of nanocarrier-mediated drug delivery and related glioma therapy. Nanocarrier-mediated drug delivery techniques to cross the BBB (liposomes, micelles, inorganic systems, polymeric nanoparticles, nanogel system, and biomimetic nanoparticles) are explored. Finally, the use of nanotherapeutic approaches in the treatment of glioblastoma including chemotherapy, radiotherapy, photothermal therapy, gene therapy, glioma genome editing, immunotherapy, chimeric antigen receptor (CAR) T-cells, immune checkpoint modulators, immune photothermal therapy, vaccine-based immunotherapy, and combination therapy is summarized. Furthermore, this article offers various views on the clinical applicability of nanomedicine.

Combined anti-angiogenic and cytotoxic treatment of a solid tumour: In silico investigation of a xenograft animal model's digital twin

Anti-angiogenic (AA) treatments have received significant research interest due to the key role of angiogenesis in cancer progression. AA agents can have a strong effect on cancer regression, by blocking new vessels and reducing the density of the existing vasculature. Moreover, in a process termed vascular normalisation, AA drugs can improve the abnormal structure and function of the tumour vasculature, enhancing the delivery of chemotherapeutics to the tumour site. Despite their promising potential, an improved understanding of AA treatments is necessary to optimise their administration as a monotherapy or in combination with other cancer treatments. In this work we present an in silico multiscale cancer model which is used to systematically interrogate the role of individual mechanisms of action of AA drugs in tumour regression. Focus is placed on the reduction of vascular density and on vascular normalisation through a parametric study, which are considered either as monotherapies or in combination with conventional/metronomic chemotherapy. The model is specified to data from a mammary carcinoma xenograft in immunodeficient mice, to enhance the physiological relevance of model predictions. Our results suggest that conventional chemotherapy might be more beneficial when combined with AA treatments, hindering tumour growth without causing excessive damage on healthy tissue. Notably, metronomic chemotherapy has shown significant potential in stopping tumour growth with minimal toxicity, even as a monotherapy. Our findings underpin the potential of our in silico framework for non-invasive and cost-effective evaluation of treatment strategies, which can enhance our understanding of combined therapeutic strategies and contribute towards improving cancer treatment management.