Clinical outcomes following salvage Gamma Knife radiosurgery for recurrent glioblastoma

Phospholipid scramblase 1 acts through the IL-6/JAK/STAT3 pathway to promote the malignant progression of glioma

BACKGROUND

Phospholipid scramblase 1 (PLSCR1) is a calcium-dependent endofacial plasma-membrane protein that plays an essential role in multiple human cancers. However, little is known about its role in glioma. This study aimed to investigate PLSCR1 function in glioma, and elucidate its underlying molecular mechanisms.

METHODS

PLSCR1 expression in human glioma cell lines (U87MG, U251, LN229, A172 and T98G) and human astrocytes was detected by western blot and qRT-PCR. PLSCR1 was silenced using si-PLSCR1-1 and si-PLSCR1-2 in LN229 and U251 cells. PLSCR1 was overexpressed using the pcDNA-PLSCR1 plasmid in T98G cells. Colony formation, 5-ethynyl-2'-deoxyuridine, flow cytometry and transwell assays were employed for measuring cell proliferation, apoptosis and mobility after PLSCR1 knockdown or overexpression. PLSCR1 function in glycolysis in glioma cells was determined through measuring the extracellular acidification rate, oxygen consumption rate, glucose consumption and lactate production. Besides, immunohistochemistry, western blot and qRT-PCR were utilized to assess mRNA and protein expression. Besides, the effect of PLSCR1 silencing on subcutaneous tumor was also monitored.

RESULTS

PLSCR1 expression was upregulated in glioma. The downregulation of PLSCR1 repressed the proliferation, mobility, epithelial-to-mesenchymal transition (EMT) and glycolysis; however, it facilitated apoptosis in glioma cells. Whereas, PLSCR1 upregulation had the opposite effect. Moreover, PLSCR1 promoted the activation of the IL-6/JAK/STAT3 pathway in glioma cells. Besides, IL-6 treatment significantly reversed the function of PLSCR1 silencing on cell proliferation, mobility, EMT, apoptosis and glycolysis. In a nude mouse tumor model, silencing PLSCR1 suppressed tumor growth via inactivating IL-6/JAK/STAT3 signaling.

CONCLUSION

Our results indicated that PLSCR1 could facilitate proliferation, mobility, EMT and glycolysis, but repress apoptosis through activating IL-6/JAK/STAT3 signaling in glioma. Therefore, PLSCR1 may function as a potential therapeutic target for glioma.

Efficacy and indications of gamma knife radiosurgery for recurrent low-and high-grade glioma

PURPOSE

To investigate the indications and efficacy of gamma knife radiosurgery (GKRS) as a salvage treatment for recurrent low-and high-grade glioma.

METHODS

This retrospective study of 107 patients with recurrent glioma treated with GKRS between 2009 and 2022, including 68 high-grade glioma (HGG) and 39 low-grade glioma (LGG) cases. The Kaplan-Meier method was used to calculate the overall survival (OS) and progression-free survival (PFS). The log-rank test was used to analyze the multivariate prognosis of the Cox proportional hazards model. Adverse reactions were evaluated according to the Common Terminology Criteria for Adverse Events version 4.03. The prognostic value of main clinical features was estimated, including histopathology, Karnofsky performance status (KPS), recurrence time interval, target location, two or more GKRS, surgery for recurrence, site of recurrence, left or right side of the brain and so on.

RESULTS

The median follow-up time was 74.5 months. The median OS and PFS were 17.0 months and 5.5 months for all patients. The median OS and PFS were 11.0 months and 5.0 months for HGG, respectively. The median OS and PFS were 49.0 months and 12.0 months for LGG, respectively. Multivariate analysis showed that two or more GKRS, left or right side of the brain and brainstem significantly affected PFS. Meanwhile, the KPS index, two or more GKRS, pathological grade, and brainstem significantly affected OS. Stratified analysis showed that surgery for recurrence significantly affected OS and PFS for LGG. KPS significantly affected OS and PFS for HGG. No serious adverse events were noted post-GKRS.

CONCLUSION

GKRS is a safe and effective salvage treatment for recurrent glioma. Moreover, it can be applied after multiple recurrences with tolerable adverse effects.

Bevacizumab and gamma knife radiosurgery for first-recurrence glioblastoma

INTRODUCTION

Glioblastoma (GBM) is the most common central nervous system malignancy in adults. Despite decades of developments in surgical management, radiation treatment, chemotherapy, and tumor treating field therapy, GBM remains an ultimately fatal disease. There is currently no definitive standard of care for patients with recurrent glioblastoma (rGBM) following failure of initial management.

OBJECTIVE

In this retrospective cohort study, we set out to examine the relative effects of bevacizumab and Gamma Knife radiosurgery on progression-free survival (PFS) and overall survival (OS) in patients with GBM at first-recurrence.

METHODS

We conducted a retrospective review of all patients with rGBM who underwent treatment with bevacizumab and/or Gamma Knife radiosurgery at Roswell Park Comprehensive Cancer Center between 2012 and 2022. Mean PFS and OS were determined for each of our three treatment groups: Bevacizumab Only, Bevacizumab Plus Gamma Knife, and Gamma Knife Only.

RESULTS

Patients in the combined treatment group demonstrated longer post-recurrence median PFS (7.7 months) and median OS (11.5 months) compared to glioblastoma patients previously reported in the literature, and showed improvements in total PFS (p=0.015), total OS (p=0.0050), post-recurrence PFS (p=0.018), and post-recurrence OS (p=0.0082) compared to patients who received either bevacizumab or Gamma Knife as monotherapy.

CONCLUSION

This study demonstrates that the combined use of bevacizumab with concurrent stereotactic radiosurgery can have improve survival in patients with rGBM.

Use of Bevacizumab in recurrent glioblastoma: a scoping review and evidence map

BACKGROUND

Glioblastoma (GBM) is the most malignant primary tumor in the brain, with poor prognosis and limited effective therapies. Although Bevacizumab (BEV) has shown promise in extending progression-free survival (PFS) treating GBM, there is no evidence for its ability to prolong overall survival (OS). Given the uncertainty surrounding BEV treatment strategies, we aimed to provide an evidence map associated with BEV therapy for recurrent GBM (rGBM).

METHODS

PubMed, Embase, and the Cochrane Library were searched for the period from January 1, 1970, to March 1, 2022, for studies reporting the prognoses of patients with rGBM receiving BEV. The primary endpoints were overall survival (OS) and quality of life (QoL). The secondary endpoints were PFS, steroid use reduction, and risk of adverse effects. A scoping review and an evidence map were conducted to explore the optimal BEV treatment (including combination regimen, dosage, and window of opportunity).

RESULTS

Patients with rGBM could gain benefits in PFS, palliative, and cognitive advantages from BEV treatment, although the OS benefits could not be verified with high-quality evidence. Furthermore, BEV combined therapy (especially with lomustine and radiotherapy) showed higher efficacy than BEV monotherapy in the survival of patients with rGBM. Specific molecular alterations (IDH mutation status) and clinical features (large tumor burden and double-positive sign) could predict better responses to BEV administration. A low dosage of BEV showed equal efficacy to the recommended dose, but the optimal opportunity window for BEV administration remains unclear.

CONCLUSIONS

Although OS benefits from BEV-containing regimens could not be verified in this scoping review, the PFS benefits and side effects control supported BEV application in rGBM. Combining BEV with novel treatments like tumor-treating field (TTF) and administration at first recurrence may optimize the therapeutic efficacy. rGBM with a low apparent diffusion coefficient (ADCL), large tumor burden, or IDH mutation is more likely to benefit from BEV treatment. High-quality studies are warranted to explore the combination modality and identify BEV-response subpopulations to maximize benefits.

Epithelial-mesenchymal transition is the main way in which glioma-associated microglia/macrophages promote glioma progression

Microglia/macrophages make up the largest population of tumor-infiltrating cells. Numerous studies have demonstrated that glioma-associated microglia/macrophages (GAMs) could promote the malignant progression of gliomas in various pathways. However, the primary function of GAMs in glioma remains inconclusive. First, by the CIBERSORT algorithm, we evaluated the content of microglia/macrophages in glioma tissues by bioinformatic analysis of omic data from thousands of glioma samples. Subsequently, we analyzed and confirmed the significant relationship between GAMs and the malignant phenotype of glioma, including survival time, IDH mutation status, and time of symptom onset. Afterward, Epithelial-Mesenchymal Transition (EMT) was identified by Gene Set Enrichment Analysis (GSEA) from numerous biological processes as the most relevant mechanism of malignant progression to GAMs. Moreover, a series of clinical samples were detected, including normal brain and various-grade glioma tissues. The results not only showed that GAMs were significantly associated with gliomas and their malignancy but also that GAMs were highly correlated with the degree of EMT in gliomas. In addition, we isolated GAMs from glioma samples and constructed co-culture models (in vitro) to demonstrate the promotion of the EMT process in glioma cells by GAMs. In conclusion, our study clarified that GAMs exert oncogenic effects with EMT in gliomas, suggesting the possibility of GAMs as immunotherapeutic targets.

Tumor Cell Infiltration into the Brain in Glioblastoma: From Mechanisms to Clinical Perspectives

Glioblastoma is the most common and malignant primary brain tumor, defined by its highly aggressive nature. Despite the advances in diagnostic and surgical techniques, and the development of novel therapies in the last decade, the prognosis for glioblastoma is still extremely poor. One major factor for the failure of existing therapeutic approaches is the highly invasive nature of glioblastomas. The extreme infiltrating capacity of tumor cells into the brain parenchyma makes complete surgical removal difficult; glioblastomas almost inevitably recur in a more therapy-resistant state, sometimes at distant sites in the brain. Therefore, there are major efforts to understand the molecular mechanisms underpinning glioblastoma invasion; however, there is no approved therapy directed against the invasive phenotype as of now. Here, we review the major molecular mechanisms of glioblastoma cell invasion, including the routes followed by glioblastoma cells, the interaction of tumor cells within the brain environment and the extracellular matrix components, and the roles of tumor cell adhesion and extracellular matrix remodeling. We also include a perspective of high-throughput approaches utilized to discover novel players for invasion and clinical targeting of invasive glioblastoma cells.

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.

Highlights in targeted nanoparticles as a delivery strategy for glioma treatment

Glioma is the most common type of Central Nervous System (CNS) neoplasia and it arises from glial cells. As glial cells are formed by different types of cells, glioma can be classified according to the cells that originate it or the malignancy grade. Glioblastoma multiforme is the most common and aggressive glioma. The high lethality of this tumor is related to the difficulty in performing surgical removal, chemotherapy, and radiotherapy in the CNS. To improve glioma treatment, a wide range of chemotherapeutics have been encapsulated in nanosystems to increase their ability to overcome the blood-brain barrier (BBB) and specifically reach the tumoral cells, reducing side effects and improving drug concentration in the tumor microenvironment. Several studies have investigated nanosystems covered with targeting ligands (e.g., proteins, peptides, aptamers, folate, and glucose) to increase the ability of drugs to cross the BBB and enhance their specificity to glioma through specific recognition by receptors on BBB and glioma cells. This review addresses the main targeting ligands used in nanosystems to overcome the BBB and promote the active targeting of drugs for glioma. Furthermore, the advantages of using these molecules in glioma treatment are discussed.

Perspective of mesenchymal transformation in glioblastoma

Despite aggressive multimodal treatment, glioblastoma (GBM), a grade IV primary brain tumor, still portends a poor prognosis with a median overall survival of 12–16 months. The complexity of GBM treatment mainly lies in the inter- and intra-tumoral heterogeneity, which largely contributes to the treatment-refractory and recurrent nature of GBM. By paving the road towards the development of personalized medicine for GBM patients, the cancer genome atlas classification scheme of GBM into distinct transcriptional subtypes has been considered an invaluable approach to overcoming this heterogeneity. Among the identified transcriptional subtypes, the mesenchymal subtype has been found associated with more aggressive, invasive, angiogenic, hypoxic, necrotic, inflammatory, and multitherapy-resistant features than other transcriptional subtypes. Accordingly, mesenchymal GBM patients were found to exhibit worse prognosis than other subtypes when patients with high transcriptional heterogeneity were excluded. Furthermore, identification of the master mesenchymal regulators and their downstream signaling pathways has not only increased our understanding of the complex regulatory transcriptional networks of mesenchymal GBM, but also has generated a list of potent inhibitors for clinical trials. Importantly, the mesenchymal transition of GBM has been found to be tightly associated with treatment-induced phenotypic changes in recurrence. Together, these findings indicate that elucidating the governing and plastic transcriptomic natures of mesenchymal GBM is critical in order to develop novel and selective therapeutic strategies that can improve both patient care and clinical outcomes. Thus, the focus of our review will be on the recent advances in the understanding of the transcriptome of mesenchymal GBM and discuss microenvironmental, metabolic, and treatment-related factors as critical components through which the mesenchymal signature may be acquired. We also take into consideration the transcriptomic plasticity of GBM to discuss the future perspectives in employing selective therapeutic strategies against mesenchymal GBM.

Advanced Imaging Techniques for Radiotherapy Planning of Gliomas

The accuracy of target delineation in radiation treatment (RT) planning of cerebral gliomas is crucial to achieve high tumor control, while minimizing treatment-related toxicity. Conventional magnetic resonance imaging (MRI), including contrast-enhanced T1-weighted and fluid-attenuated inversion recovery (FLAIR) sequences, represents the current standard imaging modality for target volume delineation of gliomas. However, conventional sequences have limited capability to discriminate treatment-related changes from viable tumors, owing to the low specificity of increased blood-brain barrier permeability and peritumoral edema. Advanced physiology-based MRI techniques, such as MR spectroscopy, diffusion MRI and perfusion MRI, have been developed for the biological characterization of gliomas and may circumvent these limitations, providing additional metabolic, structural, and hemodynamic information for treatment planning and monitoring. Radionuclide imaging techniques, such as positron emission tomography (PET) with amino acid radiopharmaceuticals, are also increasingly used in the workup of primary brain tumors, and their integration in RT planning is being evaluated in specialized centers. This review focuses on the basic principles and clinical results of advanced MRI and PET imaging techniques that have promise as a complement to RT planning of gliomas.

Research progress on radiotherapy technology and dose fraction scheme for advanced gliomas

Glioma is the most common central malignant tumor. High-grade glioma (HGG) has high malignancy and a short median survival. Complete surgical resection and comprehensive treatment with postoperative radiotherapy and chemotherapy is the recommended treatment for HGGs at present in clinic. Postoperative radiotherapy can reduce the local recurrence rate and prolong the survival time of patients. In recent years, researchers have made some progress on different radiotherapy technologies and dose fraction schemes. With the continuous development of medical technology, different groups of people should choose different dose fraction schemes, in order to realize the individualization of treatment schemes, and provide more benefits to patients. At present, the optimal radiotherapy dose, the fraction model, and how to achieve individualized radiotherapy remains unclear. In view of the poor prognosis of this disease, patients should be encouraged to participate in properly conducted experimental studies.

Novel Treatment Strategies for Glioblastoma

Glioblastoma (GBM) is the most common primary central nervous system tumor in adults. It is a highly invasive disease, making it difficult to achieve a complete surgical resection, resulting in poor prognosis with a median survival of 12–15 months after diagnosis, and less than 5% of patients survive more than 5 years. Surgical, instrument technology, diagnostic and radio/chemotherapeutic strategies have slowly evolved over time, but this has not translated into significant increases in patient survival. The current standard of care for GBM patients involving surgery, radiotherapy, and concomitant chemotherapy temozolomide (known as the Stupp protocol), has only provided a modest increase of 2.5 months in median survival, since the landmark publication in 2005. There has been considerable effort in recent years to increase our knowledge of the molecular landscape of GBM through advances in technology such as next-generation sequencing, which has led to the stratification of the disease into several genetic subtypes. Current treatments are far from satisfactory, and studies investigating acquired/inherent resistance to current therapies, restricted drug delivery, inter/intra-tumoral heterogeneity, drug repurposing and a tumor immune-evasive environment have been the focus of intense research over recent years. While the clinical advancement of GBM therapeutics has seen limited progression compared to other cancers, developments in novel treatment strategies that are being investigated are displaying encouraging signs for combating this disease. This aim of this editorial is to provide a brief overview of a select number of these novel therapeutic approaches.

A preliminary study on the application of DTI in the treatment of brain tumors in motor function areas with gamma knife

OBJECTIVES

The treatment safety and efficiency as well as the life quality of patients are still main concerns in gamma knife radiosurgery. In this study, the feasibility of applying diffusion tensor imaging (DTI) in gamma knife radiosurgery for the treatment of brain tumor in motor function areas was investigated, which aims to provide protection on the pyramidal tract and preserve the motor function in patients.

PATIENTS AND METHODS

Total 74 patients with solid brain tumor were enrolled and divided into DTI group and control group. The tumor control rate was assessed at 3 months after surgery. The muscle strength of affected limb, KPS scores, ZEW scores and complications were evaluated at 3 and 6 months after gamma knife radiosurgery.

RESULTS

Our results indicated that the tumor control rate, complication rate, the muscle strength of affected limb and KPS scores were not significantly different between the two groups at 3 months after surgery. At 6 months after gamma knife radiosurgery, the complication rate (0% vs 50 %, P = 0.044), KPS scores (64.9 % vs 37.8 %, P = 0.036) and ZEW scores (78.4 % vs 54.1 %, P = 0.044) of DTI group were better than the control group. Furthermore, the stability of muscle strength in patients with limb dysfunction was significantly improved in DTI group (86.4 % vs 50 %, P = 0.028).

CONCLUSION

In summary, the application of DTI in gamma knife radiosurgery for the treatment of brain tumors in motor function areas can precisely define the tumor edge from pyramidal tract, which will support on designing individual treatment plan, reducing the incidence of complications, and improving long-term life quality in patients.

Randomized prospective trial of fractionated stereotactic radiosurgery with chemotherapy versus chemotherapy alone for bevacizumab-resistant high-grade glioma

PURPOSE

Outcomes for patients with recurrent high-grade glioma (HGG) progressing on bevacizumab (BEV) are dismal. Fractionated stereotactic radiosurgery (FSRS) has been shown to be feasible and safe when delivered in this setting, but prospective evidence is lacking. This single-institution randomized trial compared FSRS plus BEV-based chemotherapy versus BEV-based chemotherapy alone for BEV-resistant recurrent malignant glioma.

MATERIALS AND METHODS

HGG patients on BEV with tumor progression after 2 previous treatments were randomized to 1) FSRS plus BEV-based chemotherapy or 2) BEV-based chemotherapy with irinotecan, etoposide, temozolomide, or carboplatin. FSRS was delivered as 32 Gy (8 Gy × 4 fractions within 2 weeks) to the gross target volume and 24 Gy (6 Gy × 4 fractions) to the clinical target volume (fluid-attenuated inversion recovery abnormality). The primary endpoints were local control (LC) at 2 months and progression-free survival (PFS).

RESULTS

Of the 35 patients enrolled, 29 had glioblastoma (WHO IV) and 6 had anaplastic glioma (WHO III). The median number of prior recurrences was 3. Patients treated with FSRS had significantly improved PFS (5.1 vs 1.8 months, P < .001) and improved LC at 2 months (82% [14/17] vs 27% [4/15], P = .002). The overall median survival was 6.6 months (7.2 months with FSRS vs 4.8 months with chemotherapy alone, P = .11).

CONCLUSIONS

FSRS combined with BEV-based chemotherapy in recurrent HGG patients progressing on BEV is feasible and improves LC and PFS when compared to treatment with BEV-based chemotherapy alone.

Liposomal Lapatinib in Combination with Low-Dose Photodynamic Therapy for the Treatment of Glioma

BACKGROUND

Malignant gliomas are highly invasive and extremely difficult to treat tumours with poor prognosis and outcomes. Photodynamic therapy (PDT), mediated by Gleolan®, has been studied previously with partial success in treating these tumours and extending lifetime. We aim to determine whether combining PDT using ALA-protoporphyrin IX (PpIX) with a liposomal formulation of the clinical epidermal growth factor receptor (EGFR) inhibitor, lapatinib, would increase the anti-tumour PDT efficacy.

METHODS

Lapatinib was given in vitro and in vivo 24 h prior to PDT and for 3-5 days following PDT to elicit whether the combination provided any benefits to PDT therapy. Live-cell imaging, in vitro PDT, and in vivo studies were performed to elucidate the effect lapatinib had on PDT for a variety of glioma cell lines and as well as GSC-30 neurospheres in vivo.

RESULTS

PDT combined with lapatinib led to a significant increase in PpIX accumulation, and reductions in the LD₅₀ of PpIX mediated PDT in two EGFR-driven cell lines, U87 and U87vIII, tested (p < 0.05). PDT + lapatinib elicited stronger MRI-quantified glioma responses following PDT for two human glioma-derived tumours (U87 and GSC-30) in vivo (p < 0.05). Furthermore, PDT leads to enhanced survival in rats following treatment with lapatinib compared to lapatinib alone and PDT alone (p < 0.05).

CONCLUSIONS

As lapatinib is approved for other oncological indications, a realization of its potential combination with PDT and in fluorescence-guided resection could be readily tested clinically. Furthermore, as its use would only be in acute settings, long-term resistance should not pose an issue as compared to its use as monotherapy.

Gamma Knife radiosurgery: Scenarios and support for re-irradiation

Stereotactic radiosurgery (SRS) involves the focal delivery of large, cytotoxic doses of radiation to small targets within the brain, often located in close proximity to radiosensitive normal tissue structures and requiring very low procedural uncertainties to perform safely. Historically, neurosurgeons considered SRS as a one-time, single session procedure. However therapeutic advances and a better understanding of the clinical response to SRS have caused a renewal of interest in a variety of re-irradiation scenarios; including re-irradiation of the same target after prior SRS, SRS treatments after prior broad-field radiation, hypofractionated treatments, and volume-staged treatments. Re-irradiation may in some cases require even greater effort towards minimizing treatment uncertainties as compared to one-time-only treatments. Gamma Knife radiosurgery (GKRS) has evolved over time in ways that directly supports many re-irradiation scenarios while helping to minimize overall procedural uncertainty.

The SR-B1 Receptor as a Potential Target for Treating Glioblastoma

Purpose

The goal of these studies was to provide proof of concept for a novel targeted therapy for Glioblastoma Multiforme (GBM). Methods. These studies involve the evaluation of reconstituted high density lipoprotein (rHDL) nanoparticles (NPs) as delivery agents for the drug, mammalian Target of Rapamycin (mTOR) inhibitor Everolimus (EVR) to GBM cells. Cytotoxicity studies and assessment of downstream effects, including apoptosis, migration, and cell cycle events, were probed, in relation to the expression of scavenger receptor B type 1 (SR-B1) by GBM cells.

Results

Findings from cytotoxicity studies indicate that the rHDL/EVR formulation was 185 times more potent than free EVR against high SR-B1 expressing cell line (LN 229). Cell cycle analysis revealed that rHDL/EVR treated LN229 cells had a 5.8 times higher apoptotic cell population than those treated with EVR. The sensitivity of GBM cells to EVR treatment was strongly correlated with SR-B1 expression.

Conclusions

These studies present strong proof of concept regarding the efficacy of delivering EVR and likely other agents, via a biocompatible transport system, targeted to the SR-B1 receptor that is upregulated in most cancers, including GBM. Targeting the SR-B1 receptor could thus lead to effective personalized therapy of GBM.

Inhibition of ATM kinase upregulates levels of cell death induced by cannabidiol and γ-irradiation in human glioblastoma cells

Despite advances in glioblastoma (GBM) therapy, prognosis of the disease remains poor with a low survival rate. Cannabidiol (CBD) can induce cell death and enhance radiosensitivity of GBM but not normal astrocytes. Inhibition of ATM kinase is an alternative mechanism for radiosensitization of cancer cells. In this study, we increased the cytotoxic effects of the combination of CBD and γ-irradiation in GBM cells through additional inhibition of ATM kinase with KU60019, a small molecule inhibitor of ATM kinase. We observed in GBM cells treated by CBD, γ-irradiation and KU60019 high levels of apoptosis together with strong upregulation of the percentage of G2/M-arrested cells, blockade of cell proliferation and a massive production of pro-inflammatory cytokines. Overall, these changes caused both apoptotic and non-apoptotic inflammation-linked cell death. Furthermore, via JNK-AP1 activation in concert with active NF-κB, CBD upregulated gene and protein expression of DR5/TRAIL-R2 and sensitize GBM cells to TRAIL-induced apoptosis. In contrast, CBD notably decreased in GBM surface levels of PD-L1, a critical immune checkpoint agent for T-lymphocytes. We also used in the present study TS543 human proneural glioma cells that were grown as spheroid culture. TS543 neurospheres exhibited dramatic sensitivity to CBD-mediated killing that was additionally increased in combination with γ-irradiation and KU60019. In conclusion, treatment of human GBM by the triple combination (CBD, γ-irradiation and KU60019) could significantly increase cell death levels in vitro and potentially improve the therapeutic ratio of GBM.

Long-term outcome data from 121 patients treated with Gamma Knife stereotactic radiosurgery as salvage therapy for focally recurrent high-grade gliomas

INTRODUCTION

We examined patient outcomes after Gamma Knife stereotactic radiosurgery (GKSRS) salvage therapy for recurrent high-grade gliomas (HGGs) to determine whether tumor grade or lesion size affected overall survival (OS) and progression-free survival (PFS).

METHODS

This single-center retrospective study assessed radiographic response and clinical outcomes following GKSRS salvage treatment of recurrent malignant gliomas (January 2005-March 2014).

RESULTS

A total of 121 patients (67 female) with 132 tumors were treated. Median (range) PFS was 4.7 (3.9-5.4) months for the cohort, 6.8 (4.6-8.9) months for initial grade 2 tumors, 4.2 (1.9-6.5) months for initial grade 3 tumors, and 4.3 (3.7-4.9) months for initial grade 4 tumors. Patients with small lesions (≤6.7 cm³; n = 53) had significantly longer median (range) PFS (6.8 [4.8-8.8], P=0.02).

CONCLUSIONS

GKSRS offers meaningful salvage therapy with minimal morbidity in appropriately selected patients with focally recurrent HGGs.

A Critical Overview of Targeted Therapies for Glioblastoma

Over the past century, treatment of malignant tumors of the brain has remained a challenge. Refinements in neurosurgical techniques, discovery of powerful chemotherapeutic agents, advances in radiotherapy, applications of biotechnology, and improvements in methods of targeted delivery have led to some extension of length of survival of glioblastoma patients. Refinements in surgery are mentioned because most of the patients with glioblastoma undergo surgery and many of the other innovative therapies are combined with surgery. However, cure of glioblastoma has remained elusive because it requires complete destruction of the tumor. Radical surgical ablation is not possible in the brain and even a small residual tumor leads to rapid recurrence that eventually kills the patient. Blood-brain barrier (BBB) comprising brain endothelial cells lining the cerebral microvasculature, limits delivery of drugs to the brain. Even though opening of the BBB in tumor core occurs locally, BBB limits systemic chemotherapy especially at the tumor periphery, where tumor cells invade normal brain structure comprising intact BBB. Comprehensive approaches are necessary to gain maximally from promising targeted therapies. Common methods used for critical evaluation of targeted therapies for glioblastoma include: (1) novel methods for targeted delivery of chemotherapy; (2) strategies for delivery through BBB and blood-tumor barriers; (3) innovations in radiotherapy for selective destruction of tumor; (4) techniques for local destruction of tumor; (5) tumor growth inhibitors; (6) immunotherapy; and (7) cell/gene therapies. Suggestions for improvements in glioblastoma therapy include: (1) controlled targeted delivery of anticancer therapy to glioblastoma through the BBB using nanoparticles and monoclonal antibodies; (2) direct introduction of genetically modified bacteria that selectively destroy cancer cells but spare the normal brain into the remaining tumor after resection; (3) use of better animal models for preclinical testing; and (4) personalized/precision medicine approaches to therapy in clinical trials and translation into practice of neurosurgery and neurooncology. Advances in these techniques suggest optimism for the future management of glioblastoma.

Cytokine Networks and Survivin Peptide-Specific Cellular Immune Responses Predict Improved Survival in Patients With Glioblastoma Multiforme

PURPOSE

We investigated serum cytokine and T-cell responses directed against tumour-associated antigens (TAAs) in association with survival of patients with glioblastoma multiforme (GBM).

PATIENTS AND METHODS

Peripheral blood from 205 treatment-naïve patients with glioma (GBM = 145; non-GBM = 60) was obtained on the day of surgery to measure (i) circulating T-cells reacting to viral antigens and TAAs, in the presence or absence of cytokine conditioning with IL-2/IL-15/IL-21 or IL-2/IL-7, and (ii) serum cytokine levels (IL-4, IL-5, IL-6, TNF-α, IFN-γ and IL-17A). Patients were followed-up for at least 1000 days post-surgery. Survivin protein and gene expression in resected GBM tumour tissue were confirmed by immunohistochemistry and real-time polymerase chain reaction, respectively. Antigen-specific T-cell responses were gauged by ICS (intracellular cytokine production). Associations between patient survival and immunological reactivity patterns were analysed using univariate and multivariate statistics.

RESULTS

Approximately 2% of patients with GBM and 18% of patients with non-GBM glioma, were alive beyond 1000 days of surgery. Univariate analysis indicated that the combination of three cytokines (IL-4/IL-5/IL-6, p = .0022; IFN-γ/TNF-α/IL-17A, p = .0083) but not a 'partial' combination of these cytokines, the IFN-γ immune response to EBV-EBNA-1 (p < .0001) as well as T-cell responses to the survivin_97-111 peptide (p = .0152) correlated with longer survival among patients with GBM. Multivariate analysis identified survivin_97-111-directed IFN-γ production with IL-2/IL-15/IL-21 conditioning (p = .024), and the combined presence of serum IFN-γ/TNF-α/IL-17a (p = .003) as independent predictors of survival.

CONCLUSION

Serum cytokine patterns and lymphocyte reactivity to survivin_97-111, particularly with IL-2, IL-15 and IL-21 conditioning may be instrumental in predicting survival among patients with GBM. This has implications for clinical follow-up of patients with GBM and the targeted development of immunotherapy for patients with CNS tumours.

Glioblastoma under Siege: An Overview of Current Therapeutic Strategies

Glioblastoma is known to be one of the most lethal and untreatable human tumors. Surgery and radiotherapy in combination with classical alkylating agents such as temozolomide offer little hope to escape a poor prognosis. For these reasons, enormous efforts are currently devoted to refine in vivo and in vitro models with the specific goal of finding new molecular aberrant pathways, suitable to be targeted by a variety of therapeutic approaches, including novel pharmaceutical formulations and immunotherapy strategies. In this review, we will first discuss current molecular classification based on genomic and transcriptomic criteria. Also, the state of the art in current clinical practice for glioblastoma therapy in the light of the recent molecular classification, together with ongoing phases II and III clinical trials, will be described. Finally, new pharmaceutical formulations such as nanoparticles and viral vectors, together with new strategies entailing the use of monoclonal antibodies, vaccines and immunotherapy agents, such as checkpoint inhibitors, will also be discussed.

Reirradiation of gliomas under stereotactic conditions: Prognostic factors for survival without relapse or side effects, a retrospective study at Tours regional university hospital (France)

PURPOSE

To search for factors correlated with relapse-free survival following stereotactic reirradiation in patients with recurrent glioma following radiochemotherapy and evaluate tolerance to this treatment.

PATIENTS AND METHODS

Initial radiotherapy was given according to the protocol of Stupp and al. Reirradiation was performed using the CyberKnife^® system. Patients could have had surgical resection initially and at the time of recurrence. We analysed 13 patients treated between July 2010 and September 2014. The median age was 55 years. The doses delivered ranged from 20 to 36Gy, in one to ten fractions.

RESULTS

Median survival after stereotactic radiotherapy was 14 months. Survival without relapse was 3.7 months. Factors significantly influencing duration of relapse-free survival were: age (P=0.04), total dose (P=0.02), dose per fraction (P=0.04) and number of fractions (P=0.01). We found no correlation between gross tumour volume, clinical target volume, grade of tumour or prescription isodose and relapse-free survival following radiochemotherapy. Three patients developed radionecrosis.

CONCLUSION

Reirradiation under stereotactic conditions is well tolerated. A dose of more than 30Gy delivered in 5 or more fractions seems to prolong relapse-free survival.

Mesothelin as a novel biomarker and immunotherapeutic target in human glioblastoma

Glioblastoma multiforme (GBM) presents the most malignant form of glioma, with a 5-year survival rate below 3% despite standard therapy. Novel immune-based therapies in improving treatment outcomes in GBM are therefore warranted. Several molecularly defined targets have been identified mediating anti-GBM cellular immune responses. Mesothelin is a tumor-associated antigen (TAA) which is expressed in several solid tumors with different histology. Here, we report the immunological significance of mesothelin in human malignant glioma. Expression of mature, surface-bound mesothelin protein was found to bein human GBM defined by immunofluorescence microscopy, and on freshly isolated, single cell suspension of GBM tumor cells and GBM tumor cell lines, determined by based on flow cytometric analysis. Peripheral blood (PB) from patients with GBM, stimulated with mesothelin peptides and IL-2, IL-15 and IL-21, exhibited increased antigen-specific IFN-γ and TNF-α production. Anti-mesothelin directed T-cell responses could also be detected in tumor - infiltrating lymphocytes (TIL) isolated from GBM speciments. Furthermore, T cells cultured in the presence of IL-2, IL-15 and IL-21 displayed enhanced mesothelin-specific CD4+ and CD8+ subset proliferation, based on ELISA and flow cytometric readouts. Mesothelin-specific IgG antibodies as well as (shed) mature mesothelin protein were detected in plasma samples from patients with GBM by indirect ELISA. Finally yet importantly, we identified distinct immune recognition hotspots within the mature mesothelin component, defined by peptide-specific IFN-γ responses from peripheral T-cells from patients with GBM. Mesothelin may therefore qualify as a viable target for immunotherapeutic approaches for patients with GBM.

Stereotactic Radiosurgery for Glioblastoma

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults and one of the most aggressive of all human cancers. GBM tumors are highly infiltrative and relatively resistant to conventional therapies. Aggressive management of GBM using a combination of surgical resection, followed by fractionated radiotherapy and chemotherapy has been shown to improve overall survival; however, GBM tumors recur in the majority of patients and the disease is most often fatal. There is a need to develop new treatment regimens and technological innovations to improve the overall survival of GBM patients. The role of stereotactic radiosurgery (SRS) for the treatment of GBM has been explored and is controversial. SRS utilizes highly precise radiation techniques to allow dose escalation and delivery of ablative radiation doses to the tumor while minimizing dose to the adjacent normal structures. In some studies, SRS with concurrent chemotherapy has shown improved local control with acceptable toxicities in select GBM patients. However, because GBM is a highly infiltrative disease, skeptics argue that local therapies, such as SRS, do not improve overall survival. The purpose of this article is to review the literature regarding SRS in both newly diagnosed and recurrent GBM, to describe SRS techniques, potential eligible SRS candidates, and treatment-related toxicities. In addition, this article will propose promising areas for future research for SRS in the treatment of GBM.

Update on Brain Tumors: New Developments in Neuro-oncologic Diagnosis and Treatment, and Impact on Rehabilitation Strategies

Brain tumors can be a source of functional impairment to patients due to neurologic sequelae associated with the tumor itself as well as treatment side effects. As a result, many of these patients may require rehabilitation services. Surgery, chemotherapy, and radiation therapy have been longstanding, primary treatment modalities in the management of brain tumors, though these treatments continue to evolve given new developments in research and technology. A better understanding of the diagnostic workup and current treatment standards helps the physiatrist and rehabilitation team identify rehabilitation services needed, recognize potential side-effects from anticipated or concurrent treatments, and coordinate care with referral sources. The purpose of this article is to review these new advances in diagnosis and treatment of patients with brain tumors, as well as discuss the rehabilitation implications for this population, including factors such as rehabilitation approach, timing of concomitant treatment, cost management, and coordination of care.

Biopsy vs. extensive resection for first recurrence of glioblastoma: is a prospective clinical trial warranted?

BACKGROUND

Glioblastoma is an aggressive and almost universally fatal tumor. The prognosis at the time of recurrence has generally been poor, with overall survival typically in the range of 4-40 weeks. The merits of surgical resection (vs. open biopsy, to confirm recurrence via histology) in addition to conventional adjuvant chemotherapy have been the subject of longstanding debate. We wondered whether it would possible to conduct a trial at our institution to settle this question definitively with Class I evidence.

RESULTS

Initially, we had hoped to conduct a randomized, unblinded prospective clinical trial. However on closer inspection it appeared that such an undertaking would pose significant practical challenges. Thus we present our protocol in draft form. In keeping with recommended outcomes for these tumors, the primary endpoint would be median progression free survival. Secondary end points would be: median overall survival (mOS, from time of recurrence) and change in Karnofsky Performance Status over time. Patients would be eligible at the time of first recurrence if they had received conventional treatment until that point and at least 1 month had elapsed since the time of radiation. All patients would be considered potentially eligible for enrollment (unless the decision regarding resection was already clear-cut in view of other factors). Using Cox's proportional hazards model, we estimate that at least 456 patients would be necessary to demonstrate an increase in the hazard ratio to 1.3 for those undergoing biopsy alone. This magnitude of benefit is estimated based on a review of retrospective studies.

DISCUSSION

If restricted to our Institution alone, which sees approximately 100-150 new cases of glioblastoma each year, a trial of this nature would be likely to take around 10 years. Furthermore, there may be significant reluctance on the part of patients and physicians to participate. There is also the opportunity cost of excluding patients from other trials to consider. We recognize that the estimate of the magnitude of effect may be conservative. As things stand, we feel that multi-institutional collaboration would almost certainly be required for an undertaking of this kind.

Pharmacological doses of daily ascorbate protect tumors from radiation damage after a single dose of radiation in an intracranial mouse glioma model

Pharmacological ascorbate is currently used as an anti-cancer treatment, potentially in combination with radiation therapy, by integrative medicine practitioners. In the acidic, metal-rich tumor environment, ascorbate acts as a pro-oxidant, with a mode of action similar to that of ionizing radiation; both treatments kill cells predominantly by free radical-mediated DNA damage. The brain tumor, glioblastoma multiforme (GBM), is very resistant to radiation; radiosensitizing GBM cells will improve survival of GBM patients. Here, we demonstrate that a single fraction (6 Gy) of radiation combined with a 1 h exposure to ascorbate (5 mM) sensitized murine glioma GL261 cells to radiation in survival and colony-forming assays in vitro. In addition, we report the effect of a single fraction (4.5 Gy) of whole brain radiation combined with daily intraperitoneal injections of ascorbate (1 mg/kg) in an intracranial GL261 glioma mouse model. Tumor-bearing C57BL/6 mice were divided into four groups: one group received a single dose of 4.5 Gy to the brain 8 days after tumor implantation, a second group received daily intraperitoneal injections of ascorbate (day 8-45) after implantation, a third group received both treatments and a fourth control group received no treatment. While radiation delayed tumor progression, intraperitoneal ascorbate alone had no effect on tumor progression. Tumor progression was faster in tumor-bearing mice treated with radiation and daily ascorbate than in those treated with radiation alone. Histological analysis showed less necrosis in tumors treated with both radiation and ascorbate, consistent with a radio-protective effect of ascorbate in vivo. Discrepancies between our in vitro and in vivo results may be explained by differences in the tumor microenvironment, which determines whether ascorbate remains outside the cell, acting as a pro-oxidant, or whether it enters the cells and acts as an anti-oxidant.