Targeted Therapies for the Treatment of Glioblastoma in Adults

Isolation and Characterization of the First Antigen-Specific EGFRvIII vNAR from Freshwater Stingray (Potamotrygon spp.) as a Drug Carrier in Glioblastoma Cancer Cells

Glioblastoma is the most common and highly malignant brain tumor in adults. New targeted therapeutic approaches are imperative. EGFRvIII has appealing therapeutic targets using monoclonal antibodies. Thus, endeavors toward developing new mAbs therapies for GBM capable of targeting the tumor EGFRvIII biomarker must prevail to improve the patient's prognosis. Here, we isolated and characterized an anti-EGFRvIII vNAR from a non-immune freshwater stingray mixed library, termed vNAR R426. The vNAR R426 and pEGFRvIII interaction was demonstrated by molecular docking and molecular dynamics, and the recognition of EGFRvIII in vitro was further confirmed by cell immunofluorescence staining. Moreover, the vNAR R426 was shown to be an effective cisplatin drug carrier in the U87-MG glioma cell line. The cisplatin-coupled vNAR demonstrated highly significant differences when compared to free CDDP at 72 h. Notably, the cisplatin-vNAR carrier achieved better efficacy in the U87-MG cell line. Thus, we described the vNAR R426 internalization by receptor-mediated endocytosis and the subsequent COPI-mediated nuclear translocation of EGFRvIII and highlighted the importance of this shuttle mechanism to enhance the targeted delivery of cisplatin within the glioma cell's nucleus and improved cytotoxic effect. In conclusion, vNAR R426 could be a potential therapeutic carrier for EGFRvIII-targeted glioblastoma and cancer therapies.

vNARs as Neutralizing Intracellular Therapeutic Agents: Glioblastoma as a Target

Glioblastoma is the most prevalent and fatal form of primary brain tumors. New targeted therapeutic strategies for this type of tumor are imperative given the dire prognosis for glioblastoma patients and the poor results of current multimodal therapy. Previously reported drawbacks of antibody-based therapeutics include the inability to translocate across the blood-brain barrier and reach intracellular targets due to their molecular weight. These disadvantages translate into poor target neutralization and cancer maintenance. Unlike conventional antibodies, vNARs can permeate tissues and recognize conformational or cryptic epitopes due to their stability, CDR3 amino acid sequence, and smaller molecular weight. Thus, vNARs represent a potential antibody format to use as intrabodies or soluble immunocarriers. This review comprehensively summarizes key intracellular pathways in glioblastoma cells that induce proliferation, progression, and cancer survival to determine a new potential targeted glioblastoma therapy based on previously reported vNARs. The results seek to support the next application of vNARs as single-domain antibody drug-conjugated therapies, which could overcome the disadvantages of conventional monoclonal antibodies and provide an innovative approach for glioblastoma treatment.

Circ_0027446 promotes malignant development of glioblastoma by interacting with miR-346 to up-regulate PGK1

Circular RNAs (circRNAs) can play essential roles in tumor development, including glioblastoma (GBM). The current study was performed to explore the function and mechanism of circ_0027446 in GBM progression. Circ_0027446, microRNA-346 (miR-346) and Phosphoglycerate kinase 1 (PGK1) levels were detected using reverse transcription-quantitative polymerase chain reaction assay. Cell behaviors were examined using Cell Counting Kit-8 assay, colony formation assay, EdU assay, flow cytometry, and transwell assay. Glycolytic metabolism was analyzed by commercial kits. The protein level was determined via western blot. The target interaction was analyzed by dual-luciferase reporter assay. Circ_0027446 function in vivo was explored by tumor xenograft assay. Circ_0027446 expression was significantly up-regulated in GBM samples and cells. Circ_0027446 down-regulation suppressed proliferation, invasion, glycolytic metabolism and enhanced apoptosis of GBM cells. MiR-346 was a target of circ_0027446, and circ_0027446 promoted GBM progression by sponging miR-346. PGK1 acted as a target gene of miR-346, and circ_0027446 interacted with miR-346 to regulate PGK1 expression. Overexpression of miR-346 inhibited malignant behaviors of GBM cells through down-regulating PGK1. Circ_0027446 contributed to tumor growth in vivo via miR-346/PGK1 axis. The current evidences demonstrated that circ_0027446 facilitated malignant progression of GBM through binding to miR-346 to up-regulate PGK1.

Histone demethylase KDM4B accelerates the progression of glioblastoma via the epigenetic regulation of MYC stability

BACKGROUND

Glioblastoma (GBM) is the most malignant and invasive human brain tumor. Histone demethylase 4B (KDM4B) is abnormally expressed in GBM, but the molecular mechanisms by which KDM4B affects the malignant tumor progression are not well defined.

METHODS

GBM cell lines and xenograft tumor samples were subjected to quantitative PCR (qPCR), Western blot, immunohistochemical staining (IHC), as well as ubiquitination, immunoprecipitation (IP), and chromatin immunoprecipitation (ChIP) assays to investigate the role of KDM4B in the progression of GBM.

RESULTS

Here, we report that KDM4B is an epigenetic activator of GBM progression. Abnormal expression of KDM4B is correlated with a poor prognosis in GBM patients. In GBM cell lines, KDM4B silencing significantly inhibited cell survival, proliferation, migration, and invasion, indicating that KDM4B is essential for the anchorage-independent growth and tumorigenic activity of GBM cells. Mechanistically, KDM4B silencing led to downregulation of the oncoprotein MYC and suppressed the expression of cell cycle proteins and epithelial-to-mesenchymal transition (EMT)-related proteins. Furthermore, we found that KDM4B regulates MYC stability through the E3 ligase complex SCFFBXL3+CRY2 and epigenetically activates the transcription of CCNB1 by removing the repressive chromatin mark histone H3 lysine 9 trimethylation (H3K9me3). Finally, we provide evidence that KDM4B epigenetically activates the transcription of miR-181d-5p, which enhances MYC stability.

CONCLUSIONS

Our study has uncovered a KDM4B-dependent epigenetic mechanism in the control of tumor progression, providing a rationale for utilizing KDM4B as a promising therapeutic target for the treatment of MYC-amplified GBM.

Neuropsychological Evaluation and Functional Magnetic Resonance Imaging Tasks in the Preoperative Assessment of Patients with Brain Tumors: A Systematic Review

BACKGROUND

Current surgical treatment of gliomas relies on a function-preserving, maximally safe resection approach. Functional Magnetic Resonance Imaging (fMRI) is a widely employed technology for this purpose. A preoperative neuropsychological evaluation should accompany this exam. However, only a few studies have reported both neuropsychological tests and fMRI tasks for preoperative planning-the current study aimed to systematically review the scientific literature on the topic.

METHODS

PRISMA guidelines were followed. We included studies that reported both neuropsychological tests and fMRI. Exclusion criteria were: no brain tumors, underage patients, no preoperative assessment, resting-state fMRI only, or healthy sample population/preclinical studies.

RESULTS

We identified 123 papers, but only 15 articles were included. Eight articles focused on language; three evaluated cognitive performance; single papers studied sensorimotor cortex, prefrontal functions, insular cortex, and cerebellar activation. Two qualitative studies focused on visuomotor function and language. According to some authors, there was a strong correlation between performance in presurgical neuropsychological tests and fMRI. Several papers suggested that selecting well-adjusted and individualized neuropsychological tasks may enable the development of personalized and more efficient protocols. The fMRI findings may also help identify plasticity phenomena to avoid unintentional damage during neurosurgery.

CONCLUSIONS

Most studies have focused on language, the most commonly evaluated cognitive function. The correlation between neuropsychological and fMRI results suggests that altered functions during the neuropsychological assessment may help identify patients who could benefit from an fMRI and, possibly, functions that should be tested. Neuropsychological evaluation and fMRI have complementary roles in the preoperative assessment.

Chimeric Antigen Receptor T Cells in Glioblastoma-Current Concepts and Promising Future

Glioblastoma (GBM) is a highly aggressive primary brain tumor that is largely refractory to treatment and, therefore, invariably relapses. GBM patients have a median overall survival of 15 months and, given this devastating prognosis, there is a high need for therapy improvement. One of the therapeutic approaches currently tested in GBM is chimeric antigen receptor (CAR)-T cell therapy. CAR-T cells are genetically altered T cells that are redirected to eliminate tumor cells in a highly specific manner. There are several challenges to CAR-T cell therapy in solid tumors such as GBM, including restricted trafficking and penetration of tumor tissue, a highly immunosuppressive tumor microenvironment (TME), as well as heterogeneous antigen expression and antigen loss. In addition, CAR-T cells have limitations concerning safety, toxicity, and the manufacturing process. To date, CAR-T cells directed against several target antigens in GBM including interleukin-13 receptor alpha 2 (IL-13Rα2), epidermal growth factor receptor variant III (EGFRvIII), human epidermal growth factor receptor 2 (HER2), and ephrin type-A receptor 2 (EphA2) have been tested in preclinical and clinical studies. These studies demonstrated that CAR-T cell therapy is a feasible option in GBM with at least transient responses and acceptable adverse effects. Further improvements in CAR-T cells regarding their efficacy, flexibility, and safety could render them a promising therapy option in GBM.

Personalized Medicine in Brain Gliomas: Targeted Therapy, Patient-Derived Tumor Models (Review)

Gliomas are the most common type of primary malignant brain tumors. The choice of treatments for these tumors was quite limited for many years, and therapy results generally remain still unsatisfactory. Recently, a significant breakthrough in the treatment of many forms of cancer occurred when personalized targeted therapies were introduced which inhibit tumor growth by affecting a specific molecular target. Another trend gaining popularity in oncology is the creation of patient-derived tumor models which can be used for drug screening to select the optimal therapy regimen. Molecular and genetic mechanisms of brain gliomas growth are considered, consisting of individual components which could potentially be exposed to targeted drugs. The results of the literature review show a higher efficacy of the personalized approach to the treatment of individual patients compared to the use of standard therapies. However, many unresolved issues remain in the area of predicting the effectiveness of a particular drug therapy regimen. The main hopes in solving this issue are set on the use of patient-derived tumor models, which can be used in one-stage testing of a wide range of antitumor drugs.

Surgical management of Glioma Grade 4: technical update from the neuro-oncology section of the Italian Society of Neurosurgery (SINch®): a systematic review

PURPOSE

The extent of resection (EOR) is an independent prognostic factor for overall survival (OS) in adult patients with Glioma Grade 4 (GG4). The aim of the neuro-oncology section of the Italian Society of Neurosurgery (SINch®) was to provide a general overview of the current trends and technical tools to reach this goal.

METHODS

A systematic review was performed. The results were divided and ordered, by an expert team of surgeons, to assess the Class of Evidence (CE) and Strength of Recommendation (SR) of perioperative drugs management, imaging, surgery, intraoperative imaging, estimation of EOR, surgery at tumor progression and surgery in elderly patients.

RESULTS

A total of 352 studies were identified, including 299 retrospective studies and 53 reviews/meta-analysis. The use of Dexamethasone and the avoidance of prophylaxis with anti-seizure medications reached a CE I and SR A. A preoperative imaging standard protocol was defined with CE II and SR B and usefulness of an early postoperative MRI, with CE II and SR B. The EOR was defined the strongest independent risk factor for both OS and tumor recurrence with CE II and SR B. For intraoperative imaging only the use of 5-ALA reached a CE II and SR B. The estimation of EOR was established to be fundamental in planning postoperative adjuvant treatments with CE II and SR B and the stereotactic image-guided brain biopsy to be the procedure of choice when an extensive surgical resection is not feasible (CE II and SR B).

CONCLUSIONS

A growing number of evidences evidence support the role of maximal safe resection as primary OS predictor in GG4 patients. The ongoing development of intraoperative techniques for a precise real-time identification of peritumoral functional pathways enables surgeons to maximize EOR minimizing the post-operative morbidity.

Recurrent Glioblastoma Treatment: State of the Art and Future Perspectives in the Precision Medicine Era

Current treatment guidelines for the management of recurrent glioblastoma (rGBM) are far from definitive, and the prognosis remains dismal. Despite recent advancements in the pharmacological and surgical fields, numerous doubts persist concerning the optimal strategy that clinicians should adopt for patients who fail the first lines of treatment and present signs of progressive disease. With most recurrences being located within the margins of the previously resected lesion, a comprehensive molecular and genetic profiling of rGBM revealed substantial differences compared with newly diagnosed disease. In the present comprehensive review, we sought to examine the current treatment guidelines and the new perspectives that polarize the field of neuro-oncology, strictly focusing on progressive disease. For this purpose, updated PRISMA guidelines were followed to search for pivotal studies and clinical trials published in the last five years. A total of 125 articles discussing locoregional management, radiotherapy, chemotherapy, and immunotherapy strategies were included in our analysis, and salient findings were critically summarized. In addition, an in-depth description of the molecular profile of rGBM and its distinctive characteristics is provided. Finally, we integrate the above-mentioned evidence with the current guidelines published by international societies, including AANS/CNS, EANO, AIOM, and NCCN.

Ribosomes and Ribosomal Proteins Promote Plasticity and Stemness Induction in Glioma Cells via Reprogramming

Glioblastoma multiforme (GBM) is a lethal tumor that develops in the adult brain. Despite advances in therapeutic strategies related to surgical resection and chemo-radiotherapy, the overall survival of patients with GBM remains unsatisfactory. Genetic research on mutation, amplification, and deletion in GBM cells is important for understanding the biological aggressiveness, diagnosis, and prognosis of GBM. However, the efficacy of drugs targeting the genetic abnormalities in GBM cells is limited. Investigating special microenvironments that induce chemo-radioresistance in GBM cells is critical to improving the survival and quality of life of patients with GBM. GBM cells acquire and maintain stem-cell-like characteristics via their intrinsic potential and extrinsic factors from their special microenvironments. The acquisition of stem-cell-like phenotypes and aggressiveness may be referred to as a reprogramming of GBM cells. In addition to protein synthesis, deregulation of ribosome biogenesis is linked to several diseases including cancer. Ribosomal proteins possess both tumor-promotive and -suppressive functions as extra-ribosomal functions. Incorporation of ribosomes and overexpression of ribosomal protein S6 reprogram and induce stem-cell-like phenotypes in GBM cells. Herein, we review recent literature and our published data on the acquisition of aggressiveness by GBM and discuss therapeutic options through reprogramming.

TRIM56 Reduces Radiosensitization of Human Glioblastoma by Regulating FOXM1-Mediated DNA Repair

Recurrent glioblastoma is characterized by resistance to radiotherapy or chemotherapy. In this study, we investigated the role of TRIM56 in radiosensitization and its potential underlying molecular mechanism. TRIM56 expression levels were measured in glioblastoma tissues and cell lines by immunohistochemical staining, western blot, and qRT-PCR. MTT assay, colony formation assay, and TUNEL assay were used to investigate the effect of TRIM56 on cell viability, cell proliferation, and cell apoptosis. Co-immunoprecipitation was used to clarify the interaction between TRIM56 and FOXM1. Finally, tumor xenograft experiments were performed to analyze the effect of TRIM56 on tumor growth in vivo. The expression of TRIM56 was significantly increased in glioblastoma tissues and cell lines and its expression was associated with poor prognosis of patients with glioblastoma. Moreover, TRIM56 reduced the radiosensitivity of glioblastoma cells and promoted DNA repairment. Mechanistically, TRIM56 promoted FOXM1 protein level, enhanced the stability of FOXM1 by de-ubiquitination, and promoted DNA damage repair through FOXM1 in glioblastoma cells. TRIM56 could reduce the radiosensitivity of glioblastoma in vivo. TRIM56 may suppress the radiosensitization of human glioblastoma by regulating FOXM1-mediated DNA repair. Targeting the TRIM56 may be an effective method to reverse radiotherapy-resistant in glioblastoma recurrent.

GRP78 blockade overcomes intrinsic resistance to UBA1 inhibitor TAK-243 in glioblastoma

Glioblastoma multiforme (GBM) is the most aggressive malignant primary brain tumor of the central nervous system. Despite continuous progression in treatment options for GBM like surgery, radiotherapy, and chemotherapy, this disease still has a high rate of recurrence. The endoplasmic reticulum (ER) stress pathway is associated with chemotherapeutic drug resistance. The UBA1 inhibitor TAK-243 can induce strong ER stress. However, the sensitivity of TAK-243 varies greatly in different tumor cells. This study evaluated the antitumor effects of the GRP78 inhibitor, HA15, combined with TAK-243 on GBM in the preclinical models. HA15 synergistically enhanced the sensitivity of GBM cells to TAK-243. When compared with TAK-243 monotherapy, HA15 combined with TAK-243 significantly inhibited GBM cell proliferation. It also induced G2/M-phase arrest in the cell cycle. In vivo studies showed that HA15 combined with TAK-243 significantly inhibited the growth of intracranial GBM and prolonged survival of the tumor-bearing mice. Mechanistically, HA15 and TAK-243 synergistically activated the PERK/ATF4 and IRE1α/XBP1 signaling axes, thereby eventually activating PARP and the Caspase families, which induced cell apoptosis. Our data provided a new strategy for improving the sensitivity of GBM to TAK-243 treatment and experimental basis for further clinical trials to evaluate this combination therapy.

Targeted Extracellular Vesicles Delivered Verrucarin A to Treat Glioblastoma

Glioblastomas, accounting for approximately 50% of gliomas, comprise the most aggressive, highly heterogeneous, and malignant brain tumors. The objective of this study was to develop and evaluate a new targeted therapy, i.e., highly potent natural compound verrucarin A (Ver-A), delivered with monoclonal antibody-directed extracellular vesicle (mAb-EV). First, the high surface expression of epidermal growth factor receptor (EGFR) in glioblastoma patient tissue and cell lines was confirmed using immunohistochemistry staining, flow cytometry, and Western blotting. mAb-EV-Ver-A was constructed by packing Ver-A and tagging anti-EGFR mAb to EV generated from HEK293F culture. Confocal microscopy and the In Vivo Imaging System demonstrated that mAb-EV could penetrate the blood-brain barrier, target intracranial glioblastoma xenografts, and deliver drug intracellularly. The in vitro cytotoxicity study showed IC50 values of 2-12 nM of Ver-A. The hematoxylin and eosin staining of major organs in the tolerated dose study indicated minimal systemic toxicity of mAb-EV-Ver-A. Finally, the in vivo anti-tumor efficacy study in intracranial xenograft models demonstrated that EGFR mAb-EV-Ver-A effectively inhibited glioblastoma growth, but the combination with VEGF mAb did not improve the therapeutic efficacy. This study suggested that mAb-EV is an effective drug delivery vehicle and natural Ver-A has great potential to treat glioblastoma.

Novel insights for lncRNA MAGI2-AS3 in solid tumors

Long non-coding RNAs (lncRNAs) refer to elements of genomic transcription with more than 200 nucleotides that are not translated into proteins, but have crucial roles in cancer progression. MAGI2-AS3, a novel lncRNA, has been reported to be aberrantly expressed in many solid tumors. Increasingly, studies have demonstrated that MAGI2-AS3 expression is significantly correlated with patient clinical characteristics, and that MAGI2-AS3 can regulate multiple biological processes through target-gene regulation. Furthermore, MAGI2-AS3 may serve as both a diagnostic biomarker and as a promising therapeutic target against solid tumors. In this review, we summarize the current knowledge regarding the biological functions and related molecular mechanisms of MAGI2-AS3 in solid-tumor progression. We conclude that understanding MAGI2-AS3 properties may provide new insights into the diagnoses and treatments of solid tumors.

Quiescin Sulfhydryl Oxidase 1 Regulates the Proliferation, Migration and Invasion of Human Glioblastoma Cells via PI3K/Akt Pathway

Background

Quiescin sulfhydryl oxidase 1 (QSOX1) involves in the formation of disulfide bonds and participates in the protein folding process. In recent years, accumulating evidences have shown that QSOX1 is a biomarker for tumor development and prognosis. However, the biological function of QSOX1 in glioblastoma (GBM) remains unclear.

Materials and Methods

QSOX1 expression in glioma and overall survival of glioma patients were analyzed through The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) databases. shRNAs were used to decrease the expression of QSOX1 in U87 and U251 cells. Celltiter-Glo and colony formation assays were used to assess cell proliferation. Transwell and scratch assays were utilized to determine cell migration and invasion, the xenograft mouse models were established to evaluate the effect of QSOX1 knockdown in vivo. Western blot assays were used to detect the changes of E-cadherin/N-cadherin/vimentin and PI3K/Akt pathway.

Results

We found that QSOX1 was upregulated in glioma, especially in GBM. Upregulation of QSOX1 was correlated with poor prognosis in glioma patients. We discovered for the first time that suppression of QSOX1 expression inhibited proliferation, migration and invasion, as well as epithelial-mesenchymal transition (EMT) in GBM cell lines. In addition, phosphorylated PI3K and Akt were downregulated in the QSOX1-knockdown groups. Moreover, QSOX1 knockdown-impaired cell growth was partially rescued by Akt activator.

Conclusion

Our findings revealed that QSOX1 was a novel biomarker for GBM patients and QSOX1 promoted cell proliferation, migration and invasion through regulating PI3K/Akt pathway in GBM.