Management of GBM: a problem of local recurrence

Results from a first-in-human phase I safety trial to evaluate the use of a vascularized pericranial/temporoparietal fascial flap to line the resection cavity following resection of newly diagnosed glioblastoma

PURPOSE

The efficacy of systemic therapies for glioblastoma (GBM) remains limited due to the constraints of systemic toxicity and blood-brain barrier (BBB) permeability. Temporoparietal fascial flaps (TPFFs) and vascularized peri cranial flaps (PCF) are not restricted by the blood-brain barrier (BBB), as they derive their vascular supply from branches of the external carotid artery. Transposition of a vascularized TPFF or PCF along a GBM resection cavity may bring autologous tissue not restricted by the BBB in close vicinity to the tumor bed microenvironment, permit ingrowth of vascular channels fed by the external circulation, and offer a mechanism of bypassing the BBB. In addition, circulating immune cells in the vascularized flap may have better access to tumor-associated antigens (TAA) within the tumor microenvironment. We conducted a first-in-human Phase I trial assessing the safety of lining the resection cavity with autologous TPFF/PCF of newly diagnosed patients with GBM.

METHODS

12 patients underwent safe, maximal surgical resection of newly diagnosed GBMs, followed by lining of the resection cavity with a pedicled, autologous TPFF or PCF. Safety was assessed by monitoring adverse events. Secondary analysis of efficacy was examined as the proportion of patients experiencing progression-free disease (PFS) as indicated by response assessment in neuro-oncology (RANO) criteria and overall survival (OS). The study was powered to determine whether a Phase II study was warranted based on these early results. For this analysis, subjects who were alive and had not progressed as of the date of the last follow-up were considered censored and all living patients who were alive as of the date of last follow-up were considered censored for overall survival. For simplicity, we assumed that a 70% PFS rate at 6 months would be considered an encouraging response and would make an argument for further investigation of the procedure.

RESULTS

Median age of included patients was 57 years (range 46-69 years). All patients were Isocitrate dehydrogenase (IDH) wildtype. Average tumor volume was 56.6 cm3 (range 14-145 cm3). Resection was qualified as gross total resection (GTR) of all of the enhancing diseases in all patients. Grade III or above adverse events were encountered in 3 patients. No Grade IV or V serious adverse events occurred in the immediate post-operative period including seizure, infection, stroke, or tumor growing along the flap. Disease progression at the site of the original tumor was identified in only 4 (33%) patients (median 23 months, range 8-25 months), 3 of whom underwent re-operation. Histopathological analyses of those implanted flaps and tumor bed biopsy at repeat surgery demonstrated robust immune infiltrates within the transplanted flap. Importantly, no patient demonstrated evidence of tumor infiltration into the implanted flap. At the time of this manuscript preparation, only 4/12 (33%) of patients have died. Based on the statistical considerations above and including all 12 patients 10/12 (83.3%) had 6-month PFS. The median PFS was 9.10 months, and the OS was 17.6 months. 4/12 (33%) of patients have been alive for more than two years and our longest surviving patient currently is alive at 60 months.

CONCLUSIONS

This pilot study suggests that insertion of pedicled autologous TPFF/PCF along a GBM resection cavity is safe and feasible. Based on the encouraging response rate in 6-month PFS and OS, larger phase II studies are warranted to assess and reproduce safety, feasibility, and efficacy. TRIAL REGISTRATION NUMBER AND DATE OF REGISTRATION FOR PROSPECTIVELY REGISTERED TRIALS: ClinicalTrials.gov ID NCT03630289, dated: 08/02/2018.

In Situ Sprayed Exosome-Cross-Linked Gel as Artificial Lymph Nodes for Postoperative Glioblastoma Immunotherapy

One key challenge in postoperative glioblastoma immunotherapy is to guarantee a potent and durable T-cell response, which is restricted by the immunosuppressive microenvironment within the lymph nodes (LNs). Here, we develop an in situ sprayed exosome-cross-linked gel that acts as an artificial LN structure to directly activate the tumor-infiltrating T cells for prevention of glioma recurrence. Briefly, this gel is generated by a bio-orthogonal reaction between azide-modified chimeric exosomes and alkyne-modified alginate polymers. Particularly, these chimeric exosomes are generated from dendritic cell (DC)-tumor hybrid cells, allowing for direct and robust T-cell activation. The gel structure with chimeric exosomes as cross-linking points avoids the quick clearance by the immune system and thus prolongs the durability of antitumor T-cell immunity. Importantly, this exosome-containing immunotherapeutic gel provides chances for ameliorating functions of antigen-presenting cells (APCs) through accommodating different intracellular-acting adjuvants, such as stimulator of interferon genes (STING) agonists. This further enhances the antitumor T-cell response, resulting in the almost complete elimination of residual lesions after surgery. Our findings provide a promising strategy for postsurgical glioma immunotherapy that warrants further exploration in the clinical arena.

LncRNA RARA-AS1 could serve as a novel prognostic biomarker in pan-cancer and promote proliferation and migration in glioblastoma

Long non-coding RNAs (lncRNAs) have emerged as crucial regulators of cancer progression and are potential biomarkers for diagnosis and treatment. This study investigates the role of RARA Antisense RNA 1 (RARA-AS1) in cancer and its implications for diagnosis and treatment. Various bioinformatics tools were conducted to analyze the expression patterns, immune-related functions, methylation, and gene expression correlations of RARA-AS1, mainly including the comparisons of different subgroups and correlation analyses between RARA-AS1 expression and other factors. Furthermore, we used short hairpin RNA to perform knockdown experiments, investigating the effects of RARA-AS1 on cell proliferation, invasion, and migration in glioblastoma. Our results revealed that RARA-AS1 has distinct expression patterns in different cancers and exhibits notable correlation with prognosis. Additionally, RARA-AS1 is highly correlated with certain immune checkpoints and mismatch repair genes, indicating its potential role in immune infiltration and related immunotherapy. Further analysis identified potential effective drugs for RARA-AS1 and demonstrated its potential RNA binding protein (RBP) mechanism in glioblastoma. Besides, a series of functional experiments indicated inhibiting RARA-AS1 could decrease cell proliferation, invasion, and migration of glioblastoma cell lines. Finally, RARA-AS1 could act as an independent prognostic factor for glioblastoma patients and may serve as a promising therapeutic target. All in all, Our study provides a comprehensive understanding of the functions and implications of RARA-AS1 in pan-cancer, highlighting it as a promising biomarker for survival. It is also an independent risk factor affecting prognosis in glioblastoma and an important factor affecting proliferation and migration in glioblastoma, setting the stage for further mechanistic investigations.

Isotoxic dose escalated radiotherapy for glioblastoma based on diffusion-weighted MRI and tumor control probability-an in-silico study

OBJECTIVES

Glioblastoma (GBM) is the most common malignant primary brain tumor with local recurrence after radiotherapy (RT), the most common mode of failure. Standard RT practice applies the prescription dose uniformly across tumor volume disregarding radiological tumor heterogeneity. We present a novel strategy using diffusion-weighted (DW-) MRI to calculate the cellular density within the gross tumor volume (GTV) in order to facilitate dose escalation to a biological target volume (BTV) to improve tumor control probability (TCP).

METHODS

The pre-treatment apparent diffusion coefficient (ADC) maps derived from DW-MRI of ten GBM patients treated with radical chemoradiotherapy were used to calculate the local cellular density based on published data. Then, a TCP model was used to calculate TCP maps from the derived cell density values. The dose was escalated using a simultaneous integrated boost (SIB) to the BTV, defined as the voxels for which the expected pre-boost TCP was in the lowest quartile of the TCP range for each patient. The SIB dose was chosen so that the TCP in the BTV increased to match the average TCP of the whole tumor.

RESULTS

By applying a SIB of between 3.60 Gy and 16.80 Gy isotoxically to the BTV, the cohort's calculated TCP increased by a mean of 8.44% (ranging from 7.19 to 16.84%). The radiation dose to organ at risk is still under their tolerance.

CONCLUSIONS

Our findings indicate that TCPs of GBM patients could be increased by escalating radiation doses to intratumoral locations guided by the patient's biology (i.e., cellularity), moreover offering the possibility for personalized RT GBM treatments.

ADVANCES IN KNOWLEDGE

A personalized and voxel level SIB radiotherapy method for GBM is proposed using DW-MRI, which can increase the tumor control probability and maintain organ at risk dose constraints.

Cytostatic hypothermia and its impact on glioblastoma and survival

Patients with glioblastoma (GBM) have limited options and require novel approaches to treatment. Here, we studied and deployed nonfreezing "cytostatic" hypothermia to stunt GBM growth. This growth-halting method contrasts with ablative, cryogenic hypothermia that kills both neoplastic and infiltrated healthy tissue. We investigated degrees of hypothermia in vitro and identified a cytostatic window of 20° to 25°C. For some lines, 18 hours/day of cytostatic hypothermia was sufficient to halt division in vitro. Next, we fabricated an experimental tool to test local cytostatic hypothermia in two rodent GBM models. Hypothermia more than doubled median survival, and all rats that successfully received cytostatic hypothermia survived their study period. Unlike targeted therapeutics that are successful in preclinical models but fail in clinical trials, cytostatic hypothermia leverages fundamental physics that influences biology broadly. It is a previously unexplored approach that could provide an additional option to patients with GBM by halting tumor growth.

Cranial transposition and revascularization of autologous omentum: a novel surgical technique for resection of recurrent glioblastoma multiforme

Glioblastoma multiforme (GBM) patients continue to suffer a poor prognosis. The blood brain barrier (BBB) comprises one of the obstacles for therapy, creating a barrier that decreases the bioavailability of chemotherapeutic agents in the central nervous system. Previously, a vascularized temporoparietal fascial scalp flap (TPFF) lining the resection cavity was introduced in a trial conducted in our institution, in newly-diagnosed GBM patients in an attempt to bypass the BBB after initial resection. In this paper, we report on a new technique to bypass the BBB after re-resection and potentially to allow tumor antigens to be surveilled by the immune system. The study aims to assess the feasibility of performing a cranial transposition and revascularization of autologous omentum after re-resection of GBM. Laparoscopically harvested omental free flap was transposed to the resection cavity by a team consisting of neurosurgeons, otolaryngologists, and general surgeons. This was done as part of a single center, single arm, open-label, phase I study. Autologous abdominal omental tissue was harvested laparoscopically on its vascularized pedicle in 2 patients, transposed as a free flap, revascularized using external carotid artery, and carefully laid into the tumor resection cavity. Patients did well postoperatively returning to baseline activities. Graft viability was confirmed by cerebral angiogram. Omental cranial transposition of a laparoscopically harvested, vascularized flap, into the cavity of re-resected GBM patients is feasible and safe in the short term. Further studies are needed to ascertain whether such technique can improve progression free survival and overall survival in these patients.

Cation-Free siRNA Micelles as Effective Drug Delivery Platform and Potent RNAi Nanomedicines for Glioblastoma Therapy

Nanoparticle-based small interfering RNA (siRNA) therapy shows great promise for glioblastoma (GBM). However, charge associated toxicity and limited blood-brain-barrier (BBB) penetration remain significant challenges for siRNA delivery for GBM therapy. Herein, novel cation-free siRNA micelles, prepared by the self-assembly of siRNA-disulfide-poly(N-isopropylacrylamide) (siRNA-SS-PNIPAM) diblock copolymers, are prepared. The siRNA micelles not only display enhanced blood circulation time, superior cell take-up, and effective at-site siRNA release, but also achieve potent BBB penetration. Moreover, due to being non-cationic, these siRNA micelles exert no charge-associated toxicity. Notably, these desirable properties of this novel RNA interfering (RNAi) nanomedicine result in outstanding growth inhibition of orthotopic U87MG xenografts without causing adverse effects, achieving remarkably improved survival benefits. Moreover, as a novel type of polymeric micelle, the siRNA micelle displays effective drug loading ability. When utilizing temozolomide (TMZ) as a model loading drug, the siRNA micelle realizes effective synergistic therapy effect via targeting the key gene (signal transducers and activators of transcription 3, STAT3) in TMZ drug resistant pathways. The authors' results show that this siRNA micelle nanoparticle can serve as a robust and versatile drug codelivery platform, and RNAi nanomedicine and for effective GBM treatment.

Therapeutic potentials of resveratrol in combination with radiotherapy and chemotherapy during glioblastoma treatment: a mechanistic review

Glioblastoma, WHO grade IV astrocytoma, is the most aggressive type of brain tumors. These cancerous cells have a rapid growth rate, tendency to penetrate vital brain structures, molecular heterogeneity, etc. and this cancer is associated with a poor prognosis and low survival rate. Due to the resistance of glioblastoma cells to conventional therapeutic modalities (such as radiation therapy and chemotherapy) as well as the adverse effects of these modalities, the researchers have attempted to discover an appropriate alternative or adjuvant treatment for glioblastoma. Resveratrol, as an herbal and natural polyphenolic compound, has anti-tumoral property and has shown to be effective in GBM treatment. Resveratrol exerts its anti-tumoral effect through various mechanisms such as regulation of cell cycle progression and cell proliferation, autophagy, oxidant system, apoptosis pathways, and so on. Resveratrol in combination with radiation therapy and chemotherapy has also been used. In the present study, we summarized the current findings on therapeutic potentials of resveratrol in glioblastoma radiotherapy and chemotherapy.

Polymeric nanoparticle mediated inhibition of miR-21 with enhanced miR-124 expression for combinatorial glioblastoma therapy

Glioblastoma (GBM) is the most common and fatal form of malignant brain tumor. Despite intensive effort, there is still no effective GBM treatment. Therefore, novel and more effective GBM therapeutic approaches are highly desired. In this study, we combined polymeric nanotechnology with microRNA (miRNA) regulation technology to develop a targeted polymeric nanoparticle to co-deliver anti-miR-21 and miR-124 into the brain to effectively treat GBM. The polymeric nanoparticle decorated with Angiopep-2 peptide not only can encapsulate miRNA via triple-interaction (electrostatic, hydrogen bond and hydrophobic bonding) to protect miRNA against enzyme degradation in the blood, but also is capable of crossing blood brain barrier (BBB) and allowing targeted delivery of miRNAs to GBM tissue due to the dual-targeting function of Angiopep-2. Moreover, the co-delivered anti-miR-21 and miR-124 simultaneously regulated the mutant RAS/PI3K/PTEN/AKT signaling pathway in tumor cells, consequently achieving combinatorial GBM therapy. This combinatorial effect was confirmed by our results showing that these miRNA nanomedicines can effectively reduce tumor cell proliferation, migration and invasion as well as reducing tumor angiogenesis. Consequently, effective suppression of tumor growth and significantly improved medium survival time are observed when these miRNA nanomedicines were assessed in an orthotopic GBM xenograft model. This work indicated that our new polymeric nanoparticles successfully mediate inhibition of miR-21 and miR-124 supplementation to significantly reduce tumorigenesis, and may have strong potential in GBM therapy.

Fluorescence-Guided Surgery in the Surgical Treatment of Gliomas: Past, Present and Future

Simple Summary

Gliomas are aggressive central nervous system tumours. The emergence and recent widespread adoption of 5-aminolevulinic acid and fluorescence guided surgery have improved the extent of resection, with implications for improved survival and progression-free survival. This review describes the history, rationale and mechanism behind the use of 5-aminolevulinic acid and fluorescence-guided surgery. We also discuss current limitations and future directions for this important adjunct to glioma surgery. This review aims to provide readers with an up-to-date overview and evidence base on this important topic.

Abstract

Gliomas are central nervous systems tumours which are diffusely infiltrative and difficult to treat. The extent of surgical resection is correlated with improved outcomes, including survival and disease-free progression. Cancerous tissue can be directly visualised intra-operatively under fluorescence by administration of 5-aminolevulinic acid to the patient. The adoption of this technique has allowed surgeons worldwide to achieve greater extents of resection, with implications for improved prognosis. However, there are practical limitations to use of 5-aminolevulinic acid. New adjuncts in the field of fluorescence-guided surgery aim to improve recognition of the interface between tumour and brain with the objective of improving resection and patient outcomes.

First-in-Human Trial of EphA2-Redirected CAR T-Cells in Patients With Recurrent Glioblastoma: A Preliminary Report of Three Cases at the Starting Dose

Glioblastoma is the most common primary brain malignancy with limited treatment options. EphA2 is a tumor-associated-antigen overexpressed in glioblastoma. Pre-clinical studies have demonstrated the promise of EphA2-redirected CAR T-cells against glioblastoma. We conduct the first-in-human trial of EphA2-redirected CAR T-cells in patients with EphA2-positive recurrent glioblastoma and report the results of three patients enrolled as the first cohort receiving the starting dosage (1×10⁶ cells/kg). A single infusion of EphA2-redirected CAR T-cells was administrated intravenously, with the lymphodepletion regimen consisting of fludarabine and Cyclophosphamide. In two patients, there was grade 2 cytokine release syndrome accompanied by pulmonary edema, which resolved completely with dexamethasone medication. Except that, there was no other organ toxicity including neurotoxicity. In both the peripheral blood and cerebral-spinal-fluid, we observed the expansion of CAR T-cells which persisted for more than four weeks. In one patient, there was a transit diminishment of the tumor. Among these three patients, one patient reported SD and two patients reported PD, with overall survival ranging from 86 to 181 days. At the tested dose level (1×10⁶ cells/kg), intravenously infusion of EphA2-rediretected CAR T-cells were preliminary tolerable with transient clinical efficacy. Future study with adjusted dose and infusion frequency of CAR T-cells is warranted.

Trial Registration Numbers

NCT03423992.

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

BACKGROUND

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

METHODS

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

RESULTS AND CONCLUSIONS

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

Recent Advances in Cancer Plasticity: Cellular Mechanisms, Surveillance Strategies, and Therapeutic Optimization

The processes of recurrence and metastasis, through which cancer relapses locally or spreads to distant sites in the body, accounts for more than 90% of cancer-related deaths. At present there are very few treatment options for patients at this stage of their disease. The main obstacle to successfully treat advanced cancer is the cells' ability to change in ways that make them resistant to treatment. Understanding the cellular mechanisms that mediate this cancer cell plasticity may lead to improved patient survival. Epigenetic reprogramming, together with tumor microenvironment, drives such dynamic mechanisms favoring tumor heterogeneity, and cancer cell plasticity. In addition, the development of new approaches that can report on cancer plasticity in their native environment have profound implications for studying cancer biology and monitoring tumor progression. We herein provide an overview of recent advancements in understanding the mechanisms regulating cell plasticity and current strategies for their monitoring and therapy management.

Failure to complete standard radiation therapy in glioblastoma patients: Patterns from a national database with implications for survival and therapeutic decision making in older glioblastoma patients

INTRODUCTION

It is estimated that 5%-10% of patients with newly diagnosed glioblastoma (GBM) fail to complete standard chemoradiation (CRT). We sought to determine the impact of failure to complete CRT on survival and to identify risk factors.

METHODS

We queried the National Cancer Database and identified a cohort of 17,451 adults with GBM diagnosed from 2005 to 2012. The cohort was restricted to patients that started conventionally fractionated adjuvant chemoradiation of 1.8 to 2.0 Gy per fraction to a dose of ≤66Gy. Patients were stratified by RT dose: a) completed RT ≥ 58Gy, b) nearly completed RT ≥ 50Gy - <58Gy, and c) did not complete RT ≤ 50Gy.

RESULTS

The CRT completion rate correlated with survival, 87% of patients completed CRT and had a median OS of 13.5 months, 4% were near completers (median OS 5.7 months), and 9% did not complete RT (median OS 1.9 months). Older age was associated with a higher risk of non-completion. Twenty-eight percent of patients ≥80 years old did not complete standard CRT (OR 2.99) and 19% of 70-79-year olds did not complete CRT (OR 1.99). The adjusted mortality hazard ratio was greater for patients that did not complete CRT across all age categories and for nearly complete CRT patients older than 40 (non-significant for age < 40).

CONCLUSIONS

Failure to complete standard chemoradiation was associated with decreased survival in our cohort. Patients with risk factors for failure (like advanced age) should be considered for alternative treatments such as hypofractionated radiotherapy.

CAR T cells for brain tumors: Lessons learned and road ahead

Malignant brain tumors, including glioblastoma, represent some of the most difficult to treat of solid tumors. Nevertheless, recent progress in immunotherapy, across a broad range of tumor types, provides hope that immunological approaches will have the potential to improve outcomes for patients with brain tumors. Chimeric antigen receptors (CAR) T cells, a promising immunotherapeutic modality, utilizes the tumor targeting specificity of any antibody or receptor ligand to redirect the cytolytic potency of T cells. The remarkable clinical response rates of CD19-targeted CAR T cells and early clinical experiences in glioblastoma demonstrating safety and evidence for disease modifying activity support the potential of further advancements ultimately providing clinical benefit for patients. The brain, however, is an immune specialized organ presenting unique and specific challenges to immune-based therapies. Remaining barriers to be overcome for achieving effective CAR T cell therapy in the central nervous system (CNS) include tumor antigenic heterogeneity, an immune-suppressive microenvironment, unique properties of the CNS that limit T cell entry, and risks of immune-based toxicities in this highly sensitive organ. This review will summarize preclinical and clinical data for CAR T cell immunotherapy in glioblastoma and other malignant brain tumors, including present obstacles to advancement.

Upregulation of miR-96 promotes radioresistance in glioblastoma cells via targeting PDCD4

Glioblastoma multiforme (GBM) is the most deadly brain tumor, and it is characterized by extremely poor therapeutic response and overall survival. Adjuvant radiotherapy remains the standard of care following surgical resection. Thus, elucidating the mechanisms conferring radioresistance in GBM is extremely urgent. In the present study, miR-96 was demonstrated to be significantly upregulated in radioresistant GBM cells. Knockdown of miR-96 in the radioresistant GBM cells T98G elevated the % of apoptotic cells and reduced their clonogenic formation ability following radiotherapy. By contrast, overexpression of miR-96 in the radiosensitive GBM cells U87-MG reduced the % of apoptotic cells and increased their clonogenic formation ability following radiotherapy. Results from phosphorylated-H2A histone family member X (γH2AX) foci staining and comet assays revealed that miR-96 enhanced the DNA repair processes. Furthermore, miR-96 overexpression conferred radioresistance by downregulating programmed cell death protein 4 (PDCD4). Luciferase assay results revealed that miR-96 bound to the 3'UTR of PDCD4 mRNA. Finally, U87-MG cells regained radiosensitivity following PDCD4 overexpression. Taken together, the present is the first study to establish that upregulation of miR-96 in GBM cells confers radioresistance via targeting PDCD4, which might be a potential therapeutic target for GBM.

Human cytomegalovirus-mediated immunomodulation: Effects on glioblastoma progression

The presence of human cytomegalovirus (HCMV) and glioblastoma multiforme (GBM), first established in 2002, has developed into an area of considerable interest and controversy. Numerous studies have found evidence of possible HCMV infection of GBM tumor cells as well as myriad onco- and immunomodulatory properties exhibited by HCMV antigens and transcripts, while recent reports have failed to detect HCMV particles in GBM and question the virus' role in tumor progression. This review highlights the known immunomodulatory properties of HCMV, independent of GBM infection status, that help drive the virus from peripheral blood into the vital tissues and subsequently dampen local immune response, assisting GBM tumors in evading immune surveillance and contributing to the disease's poor prognosis. Emerging antiviral approaches to treating GBM, including antiviral drugs and immunotherapies directed against HCMV, are also examined.