Molecular characterizations of glioblastoma, targeted therapy, and clinical results to date

Targeting the Endocannabinoid System Present in the Glioblastoma Tumour Microenvironment as a Potential Anti-Cancer Strategy

The highly aggressive and invasive glioblastoma (GBM) tumour is the most malignant lesion among adult-type diffuse gliomas, representing the most common primary brain tumour in the neuro-oncology practice of adults. With a poor overall prognosis and strong resistance to treatment, this nervous system tumour requires new innovative treatment. GBM is a polymorphic tumour consisting of an array of stromal cells and various malignant cells contributing to tumour initiation, progression, and treatment response. Cannabinoids possess anti-cancer potencies against glioma cell lines and in animal models. To improve existing treatment, cannabinoids as functionalised ligands on nanocarriers were investigated as potential anti-cancer agents. The GBM tumour microenvironment is a multifaceted system consisting of resident or recruited immune cells, extracellular matrix components, tissue-resident cells, and soluble factors. The immune microenvironment accounts for a substantial volume of GBM tumours. The barriers to the treatment of glioblastoma with cannabinoids, such as crossing the blood-brain barrier and psychoactive and off-target side effects, can be alleviated with the use of nanocarrier drug delivery systems and functionalised ligands for improved specificity and targeting of pharmacological receptors and anti-cancer signalling pathways. This review has shown the presence of endocannabinoid receptors in the tumour microenvironment, which can be used as a potential unique target for specific drug delivery. Existing cannabinoid agents, studied previously, show anti-cancer potencies via signalling pathways associated with the hallmarks of cancer. The results of the review can be used to provide guidance in the design of future drug therapy for glioblastoma tumours.

miR‑137 is a diagnostic tumor‑suppressive miRNA that targets SPHK2 to promote M1‑type tumor‑associated macrophage polarization

The present study investigated the expression level of microRNA (miR)-137 in glioma tissues and cell lines and explored its potential diagnostic significance as well as its function effects on glioma cells. miR-137 expression level was detected in glioma tissues using in situ hybridization, and in glioma cell lines using reverse transcription-quantitative PCR (RT-qPCR). The diagnostic significance of miR-137 in glioma was assessed using receiver operating characteristic curve analyses. Quantibody® Human Inflammation Array 1 was used to evaluate the impact of ectopic miR-137 expression on release of cytokines in glioma cell lines. IL-13, TNF-α and IFN-γ levels were detected using ELISA. To confirm that sphingosine kinase 2 (SPHK2) is a target of miR-137, RT-qPCR, western blot analysis and dual-luciferase assay were adopted. The results demonstrated that miR-137 expression was downregulated in both glioma tissues and cell lines. Downregulation of miR-137 was significantly associated with high grade gliomas. Additionally, it was found that overexpression of miR-137 reduced IL-13, but promoted TNFα and IFN-γ production. SPHK2 knockdown inhibited IL-13 release, promoted TNF-α and IFN-γ production. SPHK2 was a direct target of miR-137. Collectively, the results of the present study indicated that miR-137 expression plays a tumor-suppressive role in glioma. It is downregulated in glioma and may promote M1-type TAMs polarization, and may be a diagnostic biomarker and potential therapeutic strategy for glioma treatment in the future.

An Overview of EGFR Mechanisms and Their Implications in Targeted Therapies for Glioblastoma

Despite all of the progress in understanding its molecular biology and pathogenesis, glioblastoma (GBM) is one of the most aggressive types of cancers, and without an efficient treatment modality at the moment, it remains largely incurable. Nowadays, one of the most frequently studied molecules with important implications in the pathogenesis of the classical subtype of GBM is the epidermal growth factor receptor (EGFR). Although many clinical trials aiming to study EGFR targeted therapies have been performed, none of them have reported promising clinical results when used in glioma patients. The resistance of GBM to these therapies was proven to be both acquired and innate, and it seems to be influenced by a cumulus of factors such as ineffective blood-brain barrier penetration, mutations, heterogeneity and compensatory signaling pathways. Recently, it was shown that EGFR possesses kinase-independent (KID) pro-survival functions in cancer cells. It seems imperative to understand how the EGFR signaling pathways function and how they interconnect with other pathways. Furthermore, it is important to identify the mechanisms of drug resistance and to develop better tailored therapeutic agents.

MiR-195 connects lncRNA RUNX1-IT1 and cyclin D1 to regulate the proliferation of glioblastoma cells

AIMS

LncRNA RUNX1-IT1 has been characterized as a tumor suppressive lncRNA in several cancers, while its role in glioblastoma (GBM) is unknown. This study aimed to investigate the potential involvement of RUNX1-IT1 in GBM.

METHODS

Expression of RUNX1-IT1 in GBM tissues and paired non-tumor tissues was determined by RT-qPCR. The interaction between RUNX1-IT1 and miR-195 was analyzed by dual luciferase activity assay. Overexpression of RUNX1-IT1 and miR-195 was achieved in GBM cells to explore the interaction between them. The effects of RUNX1-IT1 and miR-195 overexpression on the expression of cyclin D1 were analyzed by RT-qPCR and Western blot. Cell proliferation was analyzed by CCK-8 assay.

RESULTS

RUNX1-IT1 was upregulated in GBM. RUNX1-IT1 and miR-195 interacted with each other, but failed to regulate the expression of each other. Overexpression of RUNX1-IT1 resulted in the upregulation of cyclin D1, and also reduced the effects of miR-195 overexpression on cyclin D1 expression. RUNX1-IT1 and cyclin overexpression increased cell proliferation, while miR-195 overexpression decreased cell proliferation. In addition, RUNX1-IT1 overexpression reduced the effects of miR-195 overexpression on cell proliferation.

CONCLUSIONS

RUNX1-IT1 may sponge miR-195 to upregulate cyclin D1, thereby increasing the proliferation of glioblastoma cells.

Network pharmacological analysis of active components of Xiaoliu decoction in the treatment of glioblastoma multiforme

Background: Glioblastoma multiforme (GBM) is the most aggressive primary nervous system brain tumor. There is still a lack of effective methods to control its progression and recurrence in clinical treatment. It is clinically found that Xiaoliu Decoction (XLD) has the effect of treating brain tumors and preventing tumor recurrence. However, its mechanism is still unclear.

Methods: Search the Traditional Chinese Medicine System Pharmacology Database (TCSMP) for efficient substances for the treatment of XLD in the treatment of GBM, and target the targeted genes of the effective ingredients to construct a network. At the same time, download GBM-related gene expression data from the TCGA and GTEX databases, screen differential expression bases, and establish a drug target disease network. Through bioinformatics analysis, the target genes and shared genes of the selected Chinese medicines are analyzed. Finally, molecular docking was performed to further clarify the possibility of XLD in multiple GBMs.

Results: We screened 894 differentially expressed genes in GBM, 230 XLD active ingredients and 169 predicted targets of its active compounds, of which 19 target genes are related to the differential expression of GBM. Bioinformatics analysis shows that these targets are closely related to cell proliferation, cell cycle regulation, and DNA synthesis. Finally, through molecular docking, it was further confirmed that Tanshinone IIA, the active ingredient of XLD, was tightly bound to key proteins.

Conclusion: To sum up, the results of this study suggest that the mechanism of XLD in the treatment of GBM involves multiple targets and signal pathways related to tumorigenesis and development. This study not only provides a new theoretical basis for the treatment of glioblastoma multiforme with traditional Chinese medicine, but also provides a new idea for the research and development of targeted drugs for the treatment of glioblastoma multiforme.

Lipoprotein Deprivation Reveals a Cholesterol-Dependent Therapeutic Vulnerability in Diffuse Glioma Metabolism

Simple Summary

High-grade gliomas are aggressive cancers that arise in children and adults, for which there is an urgent need for more effective drug therapies. Targeting the energy requirements (‘metabolism’) of these cancer cells may offer a new avenue for therapy. Cholesterol is a fatty substance found on the surface of cancer cells. Our research shows that childhood high-grade gliomas require cholesterol for their energy needs. By repurposing a drug called LXR-623 to reduce the levels of cholesterol inside high-grade glioma cancer cells, we could impair the growth of these cells in laboratory conditions. These results provide evidence for future experiments using LXR-623 to test whether this drug is able to increase the survival of mice with similar high-grade gliomas.

Abstract

Poor outcomes associated with diffuse high-grade gliomas occur in both adults and children, despite substantial progress made in the molecular characterisation of the disease. Targeting the metabolic requirements of cancer cells represents an alternative therapeutic strategy to overcome the redundancy associated with cell signalling. Cholesterol is an integral component of cell membranes and is required by cancer cells to maintain growth and may also drive transformation. Here, we show that removal of exogenous cholesterol in the form of lipoproteins from culture medium was detrimental to the growth of two paediatric diffuse glioma cell lines, KNS42 and SF188, in association with S-phase elongation and a transcriptomic program, indicating dysregulated cholesterol homeostasis. Interrogation of metabolic perturbations under lipoprotein-deficient conditions revealed a reduced abundance of taurine-related metabolites and cholesterol ester species. Pharmacological reduction in intracellular cholesterol via decreased uptake and increased export was simulated using the liver X receptor agonist LXR-623, which reduced cellular viability in both adult and paediatric models of diffuse glioma, although the mechanism appeared to be cholesterol-independent in the latter. These results provide proof-of-principle for further assessment of liver X receptor agonists in paediatric diffuse glioma to complement the currently approved therapeutic regimens and expand the options available to clinicians to treat this highly debilitating disease.

Expression Profiles of HOXC6 Predict the Survival of Glioblastoma Patients and Correlate with Cell Cycle

The goal of this study was to investigate the homeobox (HOX) gene expression status and its prognostic value in glioblastoma multiforme (GBM) and to uncover the biological processes related to its expression. The prognostic value of HOX genes in GBM was systematically investigated by a genome-wide analysis of HOX gene expression profiles in GBM patient samples in The Cancer Genome Atlas (TCGA) project (microarray dataset) and validation datasets. Using the differentially expressed gene (DEG) analysis and a Cox regression model, we discovered that the HOXC6 could stratify patients into significantly different survival (p = 0.0012, log-rank test) groups in the training cohort. TCGA RNA-seq and GSE16011 datasets were used for validation. Multivariate Cox and stratification analysis indicated that HOXC6 was an independent prognostic factor after adjusting for other clinical covariates. Bioinformatic analysis suggested that the HOXC6 might be involved in the cell cycle-related biological processes and pathways that are well established in the context of glioblastoma tumorigenesis. We further explored the bioinformatic implications by gene set enrichment analysis (GSEA). Tumor cell biology experiments verified the role of HOXC6 in proliferation and cell cycle progression. In conclusion, HOXC6 might be a candidate biomarker gene for individual treatment optimization of glioblastoma. HOXC6 expression has a significant prognostic value and is related to the cell cycle process in glioblastoma.

Effects of Metformin as Add-On Therapy against Glioblastoma: An Old Medicine for Novel Oncology Therapeutics

Simple Summary

Glioblastoma is the most common and malignant primary brain tumor, with a median survival of around 14 months. The aggressiveness of glioblastoma is due to intense cell proliferation, angiogenesis, invasiveness, genetic instability, resistance to therapies and high frequency of relapses. These features render glioblastoma almost incurable, considered an extreme therapeutic challenge. In the last few decades, it has been observed a reduced cancer incidence in diabetic patients treated with metformin, an oral hypoglycemic drug. The reported ability of metformin to arrest cancer cell growth in in vitro and in vivo experimental tumor models, have suggested the possibility to reconsider metformin as an anti-cancer add-on therapy, but further investigations about molecular mechanisms and optimal therapeutic regimens are needed. Here, we tested the efficacy of metformin against primary glioblastoma endothelial cells, responsible for tumor angiogenesis, invasiveness and resistance to therapy, reporting promising results and advancing a novel target of metformin, the “sphingolipid rheostat”.

Abstract

Background: Glioblastoma is the most aggressive primary brain malignancy in adults, with a poor prognosis of about 14 months. Recent evidence ascribed to metformin (MET), an antihyperglycemic drug, the potential to reduce cancer incidence and progression, but the molecular mechanisms underlying these effects need to be better investigated. Methods: Here, we tested the efficacy of MET on n = 10 primary glioblastoma endothelial cells (GECs), by viability and proliferation tests, as MTT and Live/Dead assays, apoptosis tests, as annexin V assay and caspase 3/7 activity, functional tests as tube-like structure formation and migration assay and by mRNA and protein expression performed by quantitative real-time PCR analysis (qRT-PCR) and Western Blot, respectively. Results: Data resulting revealed a time- and μ-dependent ability of MET to decrease cell viability and proliferation, increasing pro-apoptotic mechanisms mediated by caspases 3/7. Also, MET impacted GEC functionality with a significant decrease of angiogenesis and invasiveness potential. Mechanistically, MET was able to interfere with sphingolipid metabolism, weakening the oncopromoter signaling promoted by sphingosine-1-phosphate (S1P) and shifting the balance toward the production of the pro-apoptotic ceramide. Conclusions: These observations ascribed to MET the potential to serve as add-on therapy against glioblastoma, suggesting a repurposing of an old, totally safe and tolerable drug for novel oncology therapeutics.

An oncogenic splice variant of PDGFRα in adult glioblastoma as a therapeutic target for selective CDK4/6 inhibitors

Understanding human genome alterations is necessary to optimize genome-based cancer therapeutics. However, some newly discovered mutations remain as variants of unknown significance (VUS). Here, the mutation c.1403A > G in exon 10 of the platelet-derived growth factor receptor-alpha (PDGFRA) gene, a VUS found in adult glioblastoma multiforme (GBM), was introduced in human embryonal kidney 293 T (HEK293T) cells using genome editing to investigate its potential oncogenic functions. Genome editing was performed using CRISPR/Cas9; the proliferation, drug sensitivity, and carcinogenic potential of genome-edited cells were investigated. We also investigated the mechanism underlying the observed phenotypes. Three GBM patients carrying the c.1403A > G mutation were studied to validate the in vitro results. The c.1403A > G mutation led to a splice variant (p.K455_N468delinsN) because of the generation of a 3’-acceptor splice site in exon 10. PDGFRA-mutated HEK293T cells exhibited a higher proliferative activity via PDGFRα and the cyclin-dependent kinase (CDK)4/CDK6-cyclin D1 signaling pathway in a ligand-independent manner. They showed higher sensitivity to multi-kinase, receptor tyrosine kinase, and CDK4/CDK6 inhibitors. Of the three GBM patients studied, two harbored the p.K455_N468delinsN splice variant. The splicing mutation c.1403A > G in PDGFRA is oncogenic in nature. Kinase inhibitors targeting PDGFRα and CDK4/CDK6 signaling should be evaluated for treating GBM patients harboring this mutation.

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.

WDR34 affects PI3K/Akt and Wnt/β-catenin pathways to regulates malignant biological behaviors of glioma cells

PURPOSE

Glioma is the most prevalent primary intracranial tumor globally. WDR34, a member of the WDR superfamily with five WD40 repeats, is involved in the pathogenesis of several tumors. However, the role of WDR34 in glioma progression is unknown.

METHODS

The expression and prognostic significance of WDR34 in glioma patients were analyzed using GEPIA. WDR34 expression was detected by qRT-PCR. Western blot was employed to determine the expression of Ki67, proliferating cell nuclear antigen (PCNA), matrix metallopeptidase (MMP)2, MMP9, phosphatase and tensin homolog, protein kinase B (Akt), phosphorylated Akt, β-catenin, and c-Myc. CCK-8, BrdU incorporation assay, Transwell invasion assay, flow cytometry analysis, and measurement of caspase-3 and caspase-9 activities were conducted to examine the effects of WDR34 knockdown on glioma cells.

RESULTS

WDR34 was upregulated in glioma, which predicted a poor prognosis in glioma patients. WDR34 knockdown inhibited cell proliferation and reduced the expression of Ki67 and PCNA in glioma cells. WDR34 knockdown repressed the invasive ability of glioma cells by decreasing MMP-2 and MMP-9 expression. WDR34 knockdown increased the apoptotic rate and caspase-3 and caspase-9 activities in glioma cells. The PI3K/Akt and Wnt/β-catenin pathways were inhibited after WDR34 knockdown in glioma cells. Moreover, overexpression of Akt or β-catenin reversed the function of WDR34 knockdown on proliferation, invasion, and apoptosis. WDR34 knockdown reduced tumor growth in vivo.

CONCLUSIONS

WDR34 knockdown inhibited malignant biological behaviors of glioma cells by inactivating the PI3K/Akt and Wnt/β-catenin signaling cascades.

Selective sodium iodide symporter (NIS) genetherapy of glioblastoma mediatedby EGFR-targeted lipopolyplexes

Lipo-oligomers, post-functionalized with ligands to enhance targeting, represent promising new vehicles for the tumor-specific delivery of therapeutic genes such as the sodium iodide symporter (NIS). Due to its iodide trapping activity, NIS is a powerful theranostic tool for diagnostic imaging and the application of therapeutic radionuclides. ¹²⁴I PET imaging allows non-invasive monitoring of the in vivo biodistribution of functional NIS expression, and application of ¹³¹I enables cytoreduction. In our experimental design, we used epidermal growth factor receptor (EGFR)-targeted polyplexes (GE11) initially characterized in vitro using ¹²⁵I uptake assays. Mice bearing an orthotopic glioblastoma were treated subsequently with mono-dibenzocyclooctyne (DBCO)-PEG₂₄-GE11/NIS or bisDBCO-PEG₂₄-GE11/NIS, and 24-48 h later, ¹²⁴I uptake was assessed by positron emission tomography (PET) imaging. The best-performing polyplex in the imaging studies was then selected for ¹³¹I therapy studies. The in vitro studies showed EGFR-dependent and NIS-specific transfection efficiency of the polyplexes. The injection of monoDBCO-PEG₂₄-GE11/NIS polyplexes 48 h before ¹²⁴I application was characterized to be the optimal regime in the imaging studies and was therefore used for an ¹³¹I therapy study, showing a significant decrease in tumor growth and a significant extension of survival in the therapy group. These studies demonstrate the potential of EGFR-targeted polyplex-mediated NIS gene therapy as a new strategy for the therapy of glioblastoma.

Aptamer Applications in Neuroscience

Being the predominant cause of disability, neurological diseases have received much attention from the global health community. Over a billion people suffer from one of the following neurological disorders: dementia, epilepsy, stroke, migraine, meningitis, Alzheimer's disease, Parkinson's disease, multiple sclerosis, amyotrophic lateral sclerosis, Huntington's disease, prion disease, or brain tumors. The diagnosis and treatment options are limited for many of these diseases. Aptamers, being small and non-immunogenic nucleic acid molecules that are easy to chemically modify, offer potential diagnostic and theragnostic applications to meet these needs. This review covers pioneering studies in applying aptamers, which shows promise for future diagnostics and treatments of neurological disorders that pose increasingly dire worldwide health challenges.

SP1-upregulated LBX2-AS1 promotes the progression of glioma by targeting the miR-491-5p/LIF axis

Background: Mounting evidences have shown the importance of lncRNAs in carcinogenesis and cancer progression. LBX2-AS1 is identified as an oncogenic lncRNA that is abnormally expressed in gastric cancer and lung cancer samples. This study aims to explore the potential role of LBX2-AS1 in regulating proliferation and EMT in glioma, and the underlying mechanism. Methods: Relative levels of LBX2-AS1 in glioma samples and cell lines were detected by qRT-PCR and FISH. In vivo and in vitro regulatory effects of LBX2-AS1 on proliferation and EMT were examined in the xenograft glioma model and glioma cells. The interaction between SP1 and LBX2-AS1 was assessed by ChIP. Through bioinformatic analyses, dual-luciferase reporter assay, RIP and Western blot, the regulation of LBX2-AS1 and miR-491-5p on the target gene LIF was identified. Results: LBX2-AS1 was upregulated in glioma samples and cell lines, and its transcription was promoted by binding to the transcription factor SP1. As a lncRNA mainly distributed in the cytoplasm, LBX2-AS1 sponge miR-491-5p to further upregulate LIF. The subsequent activated LIF/STAT3 signaling was responsible for promoting proliferation and EMT in glioma. Conclusion: LBX2-AS1 is upregulated by SP1 in glioma, which promotes the progression of glioma by targeting the miR-491-5p/LIF axis. In view of this, LBX2-AS1 is suggested as a novel diagnostic biomarker and therapeutic target of glioma.

Pro-Oncogenic c-Met/EGFR, Biomarker Signatures of the Tumor Microenvironment are Clinical and Therapy Response Prognosticators in Colorectal Cancer, and Therapeutic Targets of 3-Phenyl-2H-benzo[e][1,3]-Oxazine-2,4(3H)-Dione Derivatives

Genetic and environmental factors play important roles in cancer progression, metastasis, and drug resistance. Herein, we used a multiomics data analysis to evaluate the predictive and prognostic roles of genetic and epigenetic modulation of c-MET (hepatocyte growth factor receptor)/epidermal growth factor receptor (EGFR) in colorectal cancer (CRC). First, we found that overexpressions of c-MET/EGFR were associated with the infiltration of tumor immune cells and cancer-associated fibroblasts, and were of prognostic relevance in CRC cohorts. We also observed that genetic alterations of c-MET/EGFR in CRC co-occurred with other gene alterations and were associated with overexpression of messenger (m)RNA of some cancer hallmark proteins. More specifically, DNA-methylation and somatic copy number alterations of c-MET/EGFR were associated with immune infiltration, dysfunctional T-cell phenotypes, and poor prognoses of the cohorts. Moreover, we describe two novel gefitinib-inspired small molecules derivatives of 3-phenyl-2H-benzo[e] [1,3]-oxazine-2,4(3H)-dione, NSC777205 and NSC777207, which exhibited wide-spectrum antiproliferative activities and selective cytotoxic preference for drug-sensitive and multidrug-resistant melanoma, renal, central nervous system, colon, and non-small cell lung cancer cell lines. We further provided in silico mechanistic evidence implicating c-MET/EGFR/phosphatidylinositol 3-kinase (PI3K)-mammalian target of rapamycin (mTOR) inhibition in anticancer activities of those compounds. Our overall structure-activity relationship study revealed that the addition of an –OCH₃ group to salicylic core of NSC777207 was not favorable, as the added moiety led to overall less-favorable drug properties as well as weaker anticancer activities compared to the properties and activities demonstrated by NSC777205 that has no –OCH₃ substituent group. Further in vitro and in vivo analyses in tumor-bearing mice are ongoing in our lab to support this claim and to unravel the full therapeutic efficacies of NSC777205 and NSC777207 in CRC.

Taxifolin Targets PI3K and mTOR and Inhibits Glioblastoma Multiforme

Glioblastoma multiforme (GBM), the most common malignant primary brain tumor, has a very poor prognosis. With increasing knowledge of tumor molecular biology, targeted therapies are becoming increasingly integral to comprehensive GBM treatment strategies. mTOR is a key downstream molecule of the PI3K/Akt signaling pathway, integrating input signals from growth factors, nutrients, and energy sources to regulate cell growth and cell proliferation through multiple cellular responses. mTOR/PI3K dual-targeted therapy has shown promise in managing various cancers. Here, we report that taxifolin, a flavanone commonly found in milk thistle, inhibited mTOR/PI3K, promoted autophagy, and suppressed lipid synthesis in GBM. In silico analysis showed that taxifolin can bind to the rapamycin binding site of mTOR and the catalytic site of PI3K (p110α). In in vitro experiments, taxifolin inhibited mTOR and PI3K activity in five different glioma cell lines. Lastly, we showed that taxifolin suppressed tumors in mice; stimulated expression of autophagy-related genes LC3B-II, Atg7, atg12, and Beclin-1; and inhibited expression of fatty acid synthesis-related genes C/EBPα, PPARγ, FABP4, and FAS. Our observations suggest that taxifolin is potentially a valuable drug for treating GBM.

Progress and prospect in tumor treating fields treatment of glioblastoma

Glioblastoma (GBM) is a challenging cancer with poor prognosis. The classical standard for treatment is safe resection, followed by concurrent chemoradiotherapy with subsequent adjuvant temozolomide (TMZ). Despite several attempts at different treatments, the 5-year survival rate remains poor. In recent years, with the continuous progress of treatment technology, tumor treating fields (TTFields) were preferable. The device could generate an intermediate frequency alternating electric field and induce apoptosis of some specific types of cancer cells with few toxic and side effects. TTFields induced apoptosis through multiple activations of the pathway. TTFields have been Food and Drug Administration (FDA)-approved for diagnosis and recurrent GBM as additional clinical trial results are revealed. This study reviewed the current status, mechanisms, correlations with immune pathways, the prospects of applying TTFields for GBM, and the adverse events.

Next-generation sequencing reveals novel mutations in a collision tumor of glioblastoma and meningioma

Primary intracranial collision tumors are rare in patients without predisposing factors. We report such a case in a 42-year-old female who presented with headaches and altered mental status. Imaging revealed a single heterogeneous, rim-enhancing lesion in the left parieto-occipital periventricular region, involving the corpus callosum. Stereotactic biopsy demonstrated glioblastoma. Subsequent tumor resection showed histologic evidence of glioblastoma and meningioma. Next-generation sequencing was performed on both tumor components. The glioblastoma exhibited a CDKN2A homozygous deletion and novel missense mutations in TAF1L and CSMD3, while no definitive genetic alterations were identified in the meningioma. Next-generation sequencing may yield insight into molecular drivers of intracranial collision tumors and aid in identifying future therapeutic targets.

Next-generation sequencing (NGS) reveals novel mutations in a collision tumor of GBM and meningioma. NGS has the potential to yield insight into molecular drivers of intracranial tumors and identify therapeutic targets.

Pisosterol Induces G2/M Cell Cycle Arrest and Apoptosis via the ATM/ATR Signaling Pathway in Human Glioma Cells

BACKGROUND

Pisosterol, a triterpene derived from Pisolithus tinctorius, exhibits potential antitumor activity in various malignancies. However, the molecular mechanisms that mediate the pisosterol-specific effects on glioma cells remain unknown.

OBJECTIVE

This study aimed to evaluate the antitumoral effects of pisosterol on glioma cell lines.

METHODS

The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and trypan blue exclusion assays were used to evaluate the effect of pisosterol on cell proliferation and viability in glioma cells. The effect of pisosterol on the distribution of the cells in the cell cycle was performed by flow cytometry. The expression and methylation pattern of the promoter region of MYC, ATM, BCL2, BMI1, CASP3, CDK1, CDKN1A, CDKN2A, CDKN2B, CHEK1, MDM2, p14ARF and TP53 was analyzed by RT-qPCR, western blotting and bisulfite sequencing PCR (BSP-PCR).

RESULTS

Here, it has been reported that pisosterol markedly induced G2/M arrest and apoptosis and decreased the cell viability and proliferation potential of glioma cells in a dose-dependent manner by increasing the expression of ATM, CASP3, CDK1, CDKN1A, CDKN2A, CDKN2B, CHEK1, p14ARF and TP53 and decreasing the expression of MYC, BCL2, BMI1 and MDM2. Pisosterol also triggered both caspase-independent and caspase-dependent apoptotic pathways by regulating the expression of Bcl-2 and activating caspase-3 and p53.

CONCLUSION

It has been, for the first time, confirmed that the ATM/ATR signaling pathway is a critical mechanism for G2/M arrest in pisosterol-induced glioma cell cycle arrest and suggests that this compound might be a promising anticancer candidate for further investigation.

Rethinking CRITID Procedure of Brain Targeting Drug Delivery: Circulation, Blood Brain Barrier Recognition, Intracellular Transport, Diseased Cell Targeting, Internalization, and Drug Release

The past decades have witnessed great progress in nanoparticle (NP)-based brain-targeting drug delivery systems, while their therapeutic potentials are yet to be fully exploited given that the majority of them are lost during the delivery process. Rational design of brain-targeting drug delivery systems requires a deep understanding of the entire delivery process along with the issues that they may encounter. Herein, this review first analyzes the typical delivery process of a systemically administrated NPs-based brain-targeting drug delivery system and proposes a six-step CRITID delivery cascade: circulation in systemic blood, recognizing receptor on blood-brain barrier (BBB), intracellular transport, diseased cell targeting after entering into parenchyma, internalization by diseased cells, and finally intracellular drug release. By dissecting the entire delivery process into six steps, this review seeks to provide a deep understanding of the issues that may restrict the delivery efficiency of brain-targeting drug delivery systems as well as the specific requirements that may guarantee minimal loss at each step. Currently developed strategies used for troubleshooting these issues are reviewed and some state-of-the-art design features meeting these requirements are highlighted. The CRITID delivery cascade can serve as a guideline for designing more efficient and specific brain-targeting drug delivery systems.

Dissecting the mechanism of temozolomide resistance and its association with the regulatory roles of intracellular reactive oxygen species in glioblastoma

Glioblastoma is the most common primary malignant brain tumor that is usually considered fatal even with treatment. This is often a result for tumor to develop resistance. Regarding the standard chemotherapy, the alkylating agent temozolomide is effective in disease control but the recurrence will still occur eventually. The mechanism of the resistance is various, and differs in terms of innate or acquired. To date, aberrations in O⁶-methylguanine-DNA methyltransferase are the clear factor that determines drug susceptibility. Alterations of the other DNA damage repair genes such as DNA mismatch repair genes are also known to affect the drug effect. Together these genes have roles in the innate resistance, but are not sufficient for explaining the mechanism leading to acquired resistance. Recent identification of specific cellular subsets with features of stem-like cells may have role in this process. The glioma stem-like cells are known for its superior ability in withstanding the drug-induced cytotoxicity, and giving the chance to repopulate the tumor. The mechanism is complicated to administrate cellular protection, such as the enhancing ability against reactive oxygen species and altering energy metabolism, the important steps to survive. In this review, we discuss the possible mechanism for these specific cellular subsets to evade cancer treatment, and the possible impact to the following treatment courses. In addition, we also discuss the possibility that can overcome this obstacle.

Advances in radiotherapy and comprehensive treatment of high-grade glioma: immunotherapy and tumor-treating fields

High-grade gliomas (HGGs) are the most common primary malignant brain tumors. They have a high degree of malignancy and show invasive growth. The personal treatment plan for HGG is based on the patient's age, performance status, and degree of tumor invasion. The basic treatment plan for HGG involves tumor resection, radiotherapy (RT) with concomitant temozolomide (TMZ), and adjuvant TMZ chemotherapy. The basic radiation technology includes conventional RT, three-dimensional conformal RT, intensity-modulated RT, and stereotactic RT. As our understanding of tumor pathogenesis has deepened, so-called comprehensive treatment schemes have attracted attention. These combine RT with chemotherapy, molecular targeted therapy, immunotherapy, or tumor-treating fields. These emerging treatments are expected to improve the prospects of patients with HGG. In the present article, we review the recent advances in RT and comprehensive treatment for patients with newly diagnosed and recurrent HGG.

Linking epigenetic signature and metabolic phenotype in IDH mutant and IDH wildtype diffuse glioma

AIMS

Changes in metabolism are known to contribute to tumour phenotypes. If and how metabolic alterations in brain tumours contribute to patient outcome is still poorly understood. Epigenetics impact metabolism and mitochondrial function. The aim of this study is a characterisation of metabolic features in molecular subgroups of isocitrate dehydrogenase mutant (IDHmut) and isocitrate dehydrogenase wildtype (IDHwt) gliomas.

METHODS

We employed DNA methylation pattern analyses with a special focus on metabolic genes, large-scale metabolism panel immunohistochemistry (IHC), qPCR-based determination of mitochondrial DNA copy number and immune cell content using IHC and deconvolution of DNA methylation data. We analysed molecularly characterised gliomas (n = 57) for in depth DNA methylation, a cohort of primary and recurrent gliomas (n = 22) for mitochondrial copy number and validated these results in a large glioma cohort (n = 293). Finally, we investigated the potential of metabolic markers in Bevacizumab (Bev)-treated gliomas (n = 29).

RESULTS

DNA methylation patterns of metabolic genes successfully distinguished the molecular subtypes of IDHmut and IDHwt gliomas. Promoter methylation of lactate dehydrogenase A negatively correlated with protein expression and was associated with IDHmut gliomas. Mitochondrial DNA copy number was increased in IDHmut tumours and did not change in recurrent tumours. Hierarchical clustering based on metabolism panel IHC revealed distinct subclasses of IDHmut and IDHwt gliomas with an impact on patient outcome. Further quantification of these markers allowed for the prediction of survival under anti-angiogenic therapy.

CONCLUSION

A mitochondrial signature was associated with increased survival in all analyses, which could indicate tumour subgroups with specific metabolic vulnerabilities.

Window of Opportunity Clinical Trials to Evaluate Novel Therapies for Brain Tumors

Despite significant improvement in understanding of molecular underpinnings driving glioblastoma, there is minimal improvement in overall survival of patients. This poor outcome is caused in part by traditional designs of early phase clinical trials, which focus on clinical assessments of drug toxicity and response. Window of opportunity trials overcome this shortcoming by assessing drug-induced on-target molecular alterations in post-treatment human tumor specimens. This article provides an overview of window of opportunity trials, including novel designs for incorporating biologic end points into early stage trials in context of brain tumors, and examples of successfully executed window of opportunity trials for glioblastoma.

lncRNA CTBP1-AS2 promotes proliferation and migration of glioma by modulating miR-370-3p-Wnt7a-mediated epithelial-mesenchymal transition

Glioma is one of the most common and aggressive malignant primary brain tumors, with a poor 5-year survival rate. The long noncoding RNA (lncRNA) CTBP1-AS2 has been shown to be correlated with the prognosis of cancer, but the role of CTBP1-AS2 in glioma and its concrete mechanism is fully unknown. The clinical data and tissues of glioma patients were analyzed. Cell viability and migration assays were performed. Western blotting and qRT-PCR were adopted for investigation of target protein expressions. Double luciferase assay was used to investigate the interaction between different elements. The lncRNA CTBP1-AS2 had increased expression profiles in tumor tissues, which is associated with poor prognosis. In detail, CTBP1-AS2 knockdown decreased proliferation and migration phenotypes in both U87-MG and LN229 cells. Moreover, CTBP1-AS2 knockdown suppressed the key epithelial-mesenchymal transition (EMT) markers by downregulating Wnt7a-mediated signaling. Furthermore, miR-370-3p functioned as a link that could be absorbed by CTBP1-AS2, thus regulating Wnt7a expression. Lastly, the CTBP1-AS2-miR-370-3p-Wnt7a axis modulated EMT in glioma cells in vitro and in vivo. This study provides new insights that a novel lncRNA, CTBP1-AS2, regulates EMT of glioma by modulating the miR-370-3p-Wnt7a axis.

Therapeutic Potential of Autophagy in Glioblastoma Treatment With Phosphoinositide 3-Kinase/Protein Kinase B/Mammalian Target of Rapamycin Signaling Pathway Inhibitors

Glioblastoma (GB) is the most malignant and aggressive form of brain tumor, characterized by frequent hyperactivation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway. PI3K/AKT/mTOR inhibitors have a promising clinical efficacy theoretically. However, strong drug resistance is developed in GB against the PI3K/AKT/mTOR inhibitors due to the cytoprotective effect and the adaptive response of autophagy during the treatment of GB. Activation of autophagy by the PI3K/AKT/mTOR inhibitors not only enhances treatment sensitivity but also leads to cell survival when drug resistance develops in cancer cells. In this review, we analyze how to increase the antitumor effect of the PI3K/AKT/mTOR inhibitors in GB treatment, which is achieved by various mechanisms, among which targeting autophagy is an important mechanism. We review the dual role of autophagy in both GB therapy and resistance against inhibitors of the PI3K/AKT/mTOR signaling pathway, and further discuss the possibility of using combinations of autophagy and PI3K/AKT/mTOR inhibitors to improve the treatment efficacy for GB. Finally, we provide new perspectives for targeting autophagy in GB therapy.

Aptamer-Based In Vivo Therapeutic Targeting of Glioblastoma

Glioblastoma (GBM) is the most aggressive, infiltrative, and lethal brain tumor in humans. Despite the extensive advancement in the knowledge about tumor progression and treatment over the last few years, the prognosis of GBM is still very poor due to the difficulty of targeting drugs or anticancer molecules to GBM cells. The major challenge in improving GBM treatment implicates the development of a targeted drug delivery system, capable of crossing the blood–brain barrier (BBB) and specifically targeting GBM cells. Aptamers possess many characteristics that make them ideal novel therapeutic agents for the treatment of GBM. They are short single-stranded nucleic acids (RNA or ssDNA) able to bind to a molecular target with high affinity and specificity. Several GBM-targeting aptamers have been developed for imaging, tumor cell isolation from biopsies, and drug/anticancer molecule delivery to the tumor cells. Due to their properties (low immunogenicity, long stability, and toxicity), a large number of aptamers have been selected against GBM biomarkers and tested in GBM cell lines, while only a few of them have also been tested in in vivo models of GBM. Herein, we specifically focus on aptamers tested in GBM in vivo models that can be considered as new diagnostic and/or therapeutic tools for GBM patients’ treatment.

Multi-Cell Type Glioblastoma Tumor Spheroids for Evaluating Sub-Population-Specific Drug Response

Glioblastoma (GBM) is a lethal, incurable form of cancer in the brain. Even with maximally aggressive surgery and chemoradiotherapy, median patient survival is 14.5 months. These tumors infiltrate normal brain tissue, are surgically incurable, and universally recur. GBMs are characterized by genetic, epigenetic, and microenvironmental heterogeneity, and they evolve spontaneously over time and as a result of treatment. However, tracking such heterogeneity in real time in response to drug treatments has been impossible. Here we describe the development of an in vitro GBM tumor organoid model that is comprised of five distinct cellular subpopulations (4 GBM cell lines that represent GBM subpopulations and 1 astrocyte line), each fluorescently labeled with a different color. These multi-cell type GBM organoids are then embedded in a brain-like hyaluronic acid hydrogel for subsequent studies involving drug treatments and tracking of changes in relative numbers of each fluorescently unique subpopulation. This approach allows for the visual assessment of drug influence on individual subpopulations within GBM, and in future work can be expanded to supporting studies using patient tumor biospecimen-derived cells for personalized diagnostics.

IDH-mutant gliomas harbor fewer regulatory T cells in humans and mice

The metabolic gene isocitrate dehydrogenase 1 (IDH1) is commonly mutated in lower grade glioma (LGG) and secondary glioblastoma (GBM). Regulatory T cells (Tregs) play a significant role in the suppression of antitumor immunity in human glioma. Given the importance of Tregs in the overall framework of designing immune-based therapies, a better understanding on their association with IDH mutational status remains of critical clinical importance. Using multispectral imaging analysis, we compared the incidence of Tregs in IDH-mutant and IDH wild-type glioma from patient tumor samples of LGG. An orthotopic IDH-mutant murine model was generated to evaluate the role of mutant IDH on Treg infiltration by immunohistochemistry. When compared to IDH wild-type controls, Tregs are disproportionally underrepresented in mutant disease, even when taken as a proportion of all infiltrating T cells. Our findings suggest that therapeutic agents targeting Tregs may be more appropriate in modulating the immune response to wild-type disease.

Enolase-phosphatase 1 acts as an oncogenic driver in glioma

Enolase-phosphatase 1 (ENOPH1), a newly identified enzyme involved in l-methionine biosynthesis, is associated with anxiety and depression. In this study, ENOPH1 was found to play a crucial role in promoting the proliferation and migration of glioma cells. Among high-grade glioma patients, the overall survival of the group showing high ENOPH1 expression was shorter than that of the group showing low ENOPH1 expression. ENOPH1 knockdown inhibited glioma cell proliferation and migration. In parallel, ENOPH1 knockdown suppressed tumor growth capacity and prolonged survival in an orthotopic glioma model. Mechanistically, we found that ENOPH1 activates the PI3K/AKT/mTOR signaling pathway by regulating THEM4. In conclusion, ENOPH1 is an important mediator that promotes glioma cell proliferation and migration.

A DNA Repair Inhibitor Isolated from an Ecuadorian Fungal Endophyte Exhibits Synthetic Lethality in PTEN-Deficient Glioblastoma

Disruption of the tumor suppressor PTEN, either at the protein or genomic level, plays an important role in human cancer development. The high frequency of PTEN deficiency reported across several cancer subtypes positions therapeutic approaches that exploit PTEN loss-of-function with the ability to significantly impact the treatment strategies of a large patient population. Here, we report that an endophytic fungus isolated from a medicinal plant produces an inhibitor of DNA double-strand-break repair. Furthermore, the novel alkaloid product, which we have named irrepairzepine (1), demonstrated synthetic lethal targeting in PTEN-deficient glioblastoma cells. Our results uncover a new therapeutic lead for PTEN-deficient cancers and an important molecular tool toward enhancing the efficacy of current cancer treatments.

Molecular genetic profiling reveals novel association between FLT3 mutation and survival in glioma

INTRODUCTION

Recent molecular characterization of gliomas has uncovered somatic gene variation and DNA methylation changes that are associated with etiology, prognosis, and therapeutic response. Here we describe genomic profiling of gliomas assessed for associations between genetic mutations and patient outcomes, including overall survival (OS) and recurrence-free survival (RFS).

METHODS

Mutations in a 50-gene cancer panel, 1p19q co-deletion, and MGMT promoter methylation (MGMT methylation) status were obtained from tumor tissue of 293 glioma patients. Multivariable regression models for overall survival (OS) and recurrence-free survival (RFS) were constructed for MGMT methylation, 1p19q co-deletion, and gene mutations controlling for age, treatment status, and WHO grade.

RESULTS

Mutational profiles of gliomas significantly differed based on WHO Grade, such as high prevalence of BRAF V600E, IDH1, and PTEN mutations in WHO Grade I, II/III, and IV tumors, respectively. In multivariate regression analysis, MGMT methylation and IDH1 mutations were significantly associated with improved OS (HR = 0.44, p = 0.0004 and HR = 0.21, p = 0.007, respectively), while FLT3 and TP53 mutations were significantly associated with poorer OS (HR = 19.46, p < 0.0001 and HR = 1.67, p = 0.014, respectively). MGMT methylation and IDH1 mutations were the only significant alterations associated with improved RFS in the model (HR = 0.42, p < 0.0001 and HR = 0.37, p = 0.002, respectively). These factors were then included in a combined model, which significantly exceeded the predictive value of the base model alone (age, surgery, radiation, chemo, grade) (likelihood ratio test OS p = 1.64 × 10^-8 and RFS p = 3.80 × 10^-7).

CONCLUSIONS

This study highlights the genomic landscape of gliomas in a single-institution cohort and identifies a novel association between FLT3 mutation and OS in gliomas.

Prognostic Value of C-Reactive Protein to Albumin Ratio in Glioblastoma Multiforme Patients Treated with Concurrent Radiotherapy and Temozolomide

Objective

We investigated the prognostic impact of C-reactive protein to albumin ratio (CRP/Alb) on the survival outcomes of newly diagnosed glioblastoma multiforme (GBM) patients treated with radiotherapy (RT) and concurrent plus adjuvant temozolomide (TMZ).

Methods

The pretreatment CRP and Alb records of GBM patients who underwent RT and concurrent plus adjuvant TMZ were retrospectively analyzed. The CRP/Alb was calculated by dividing serum CRP level by serum Alb level obtained prior to RT. The availability of significant cutoff value for CRP/Alb that interacts with survival was assessed with the receiver-operating characteristic (ROC) curve analysis. The primary endpoint was the association between the CRP/Alb and the overall survival (OS).

Results

A total of 153 patients were analyzed. At a median follow-up of 14.7 months, median and 5-year OS rates were 16.2 months (95% CI: 12.5–19.7) and 9.5%, respectively, for the entire cohort. The ROC curve analysis identified a significant cutoff value at 0.75 point (area under the curve: 74.9%; sensitivity: 70.9%; specificity: 67.7%; P < 0.001) for CRP/Alb that interacts with OS and grouped the patients into two: CRP/Alb <0.75 (n = 61) and ≥0.75 (n = 92), respectively. Survival comparisons revealed that the CRP/Alb <0.75 was associated with a significantly superior median (22.5 versus 15.7 months; P < 0.001) and 5-year (20% versus 0%) rates than the CRP/Alb ≥0.75, which retained its independent significance in multivariate analysis (P < 0.001).

Conclusion

Present results suggested the pretreatment CRP/Alb as a significant and independent inflammation-based index which can be utilized for further prognostic lamination of GBM patients.

LncRNA SNHG4 regulates miR-138/c-Met axis to promote the proliferation of glioblastoma cells

LncRNA SNHG4 has been reported to be an oncogenic lncRNA in osteosarcoma. Our preliminary analysis of the cancer genome atlas dataset revealed the upregulation of SNHG4 in glioblastoma (GBM). In this study, we confirmed the upregulation of SNHG4 in GBM tissues collected from GBM patients. In addition, lower survival rate of GBM patients was observed in patients with high SNHG4 expression level. SNHG4 can directly interact with miR-138, while SNHG4 expression was no altered after miR-138 overexpression. Interestingly, SNHG4 overexpression led to the upregulation of c-Met, a target of miR-138. Cell counting kit-8 assay showed that miR-138 overexpression resulted in decreased proliferation rate of GBM cells. SNHG4 and c-Met overexpression played opposite roles and reduced the effects of miR-138. Therefore, SNHG4 regulates miR-138/c-Met axis to promote the proliferation of GBM cells.

Gomisin J inhibits the glioma progression by inducing apoptosis and reducing HKII-regulated glycolysis

Glioma is a leading cause of central nervous system malignant tumor-associated deaths in the world. However, the molecular mechanisms for glioma progression are still unclear, lacking effective therapeutic strategies. Gomisin J (GomJ) is a derivative of lignan compound, and shows regulatory effects on virus, oxidative stress and tumor progression. However, the role of GomJ in the meditation of glioma progression has not been explored. In this study, we found that GomJ markedly reduced the proliferation of glioma cell lines. Mitochondrial apoptosis was highly induced by GomJ, as evidenced by the significantly up-regulated expression of cytoplastic Cyto-c and cleaved Caspase-3. In addition, mitochondrial membrane potential (MMP) and oxidative stress were highly triggered in GomJ-incubated glioma cells, accompanied with the glycolysis suppression. Importantly, we found that GomJ could dramatically reduce the expression of hexokinase II (HKII) in glioma cells. At the same time, the dissociation of HKII from voltage-dependent anion channel (VDAC) in mitochondria was markedly induced by GomJ, contributing to glycolytic repression. The in vivo experiments confirmed that GomJ obviously reduced the growth of glioma with HKII reduction and few side effects. Taken together, these results demonstrated that GomJ could inhibit the proliferation, induce apoptosis and restrain HKII-regulated glycolysis during glioma progression. Herein, GomJ with few toxicity might be served as a potential therapeutic strategy for the treatment of glioma in humans.

Newcastle Disease Virus (NDV) Oncolytic Activity in Human Glioma Tumors Is Dependent on CDKN2A-Type I IFN Gene Cluster Codeletion

Glioblastoma (GBM) is the most aggressive and frequent primary brain tumor in adults with a median overall survival of 15 months. Tumor recurrence and poor prognosis are related to cancer stem cells (CSCs), which drive resistance to therapies. A common characteristic in GBM is CDKN2A gene loss, located close to the cluster of type I IFN genes at Ch9p21. Newcastle disease virus (NDV) is an avian paramyxovirus with oncolytic and immunostimulatory properties that has been proposed for the treatment of GBM. We have analyzed the CDKN2A-IFN I gene cluster in 1018 glioma tumors and evaluated the NDV oncolytic effect in six GBM CSCs ex vivo and in a mouse model. Our results indicate that more than 50% of GBM patients have some IFN deletion. Moreover, GBM susceptibility to NDV is dependent on the loss of the type I IFN. Infection of GBM with an NDV-expressing influenza virus NS1 protein can overcome the resistance to oncolysis by NDV of type I-competent cells. These results highlight the potential of using NDV vectors in antitumor therapies.

Anti-epidermal growth factor receptor therapy for glioblastoma in adults

BACKGROUND

Glioblastoma is an uncommon but highly aggressive type of brain tumour. Significant gains have been achieved in the molecular understanding and the pathogenesis of glioblastomas, however clinical improvements are difficult to obtain for many reasons. The current standard of care involves maximal safe surgical resection followed by chemoradiation and then adjuvant chemotherapy European Organisation for Research and Treatment of Cancer and the NCIC Clinical Trials Group (EORTC-NCIC) protocol with a median survival of 14.6 months. Successive phase III international randomised controlled studies have failed to significantly demonstrate survival advantage with newer drugs. Epidermal growth factor receptor (EGFR) is observed to be aberrant in 30% to 60% of glioblastomas. The receptor aberrancy is driven by abnormal gene amplification, receptor mutation, or both, in particular the extracellular vIII domain. EGFR abnormalities are common in solid tumours, and the advent of anti-EGFR therapies in non-small cell lung cancer and colorectal adenocarcinomas have greatly improved clinical outcomes. Anti-EGFR therapies have been investigated amongst glioblastomas, however questions remain about its ongoing role in glioblastoma management. This review aimed to report on the available evidence to date and perform a systematic analysis on the risks and benefits of use of anti-EGFR therapies in glioblastomas.

OBJECTIVES

To evaluate the efficacy and harms of anti-EGFR therapies for glioblastoma in adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, EBM Reviews databases, with supplementary handsearches to identify all available and relevant studies to 20 April 2020.

SELECTION CRITERIA

All randomised controlled trials (RCTs) using anti-EGFR therapies in adults with glioblastoma were eligible for inclusion. Anti-EGFR therapies included tyrosine kinase inhibitors, monoclonal antibodies, or vaccines. The comparison included investigational product added to standard of care versus standard of care or placebo, or investigational product against standard of care or placebo.

DATA COLLECTION AND ANALYSIS

The authorship team screened the search results and recorded the extracted data for analysis. We used standard Cochrane methodology to performed quantitative meta-analysis if two or more studies had appropriate and available data. Otherwise, we conducted a qualitative and descriptive analysis. We used the GRADE system to rate the certainty of the evidence. The analysis was performed along the two clinical settings: first-line (after surgery) and recurrent disease (after failure of first line treatment). Where information was available, we documented overall survival, progression-free survival, adverse events, and quality of life data from eligible studies.

MAIN RESULTS

The combined searches initially identified 912 records (after removal of duplicates), and further screening resulted in 19 records for full consideration. We identified nine eligible studies for inclusion in the review. There were three first-line studies and six recurrent studies. Five studies used tyrosine kinase inhibitors (TKIs); two studies used monoclonal antibodies; and two studies used targeted vaccines. More recent studies presented greater detail in the conduct of their studies and thus had a lower risk of bias. We observed no evidence benefit in overall survival with the use of anti-EGFR therapy in the first-line or recurrent setting (hazard ratio (HR) 0.89, 95% confidence interval (CI) 0.76 to 1.04; 3 RCTs, 1000 participants, moderate-certainty evidence; and HR 0.79, 95% CI 0.51 to 1.21, 4 RCTs, 489 participants, low-certainty evidence, respectively). All the interventions were generally well tolerated with low-certainty evidence for lymphopenia (odds ratio (OR) 0.97, 95% CI 0.19 to 4.81; 4 RCTs, 1146 participants), neutropenia (OR 1.29, 95% CI 0.82 to 2.03; 4 RCTs, 1146 participants), and thrombocytopenia (OR 3.69, 95% CI 0.51 to 26.51; 4 RCTs, 1146 participants). A notable toxicity relates to ABT-414, where significant ocular issues were detected. The addition of anti-EGFR therapy showed no evidence of an increase in progression-free survival (PFS) in the first-line setting (HR 0.94, 95% CI 0.81 to 1.10; 2 RCTs, 894 participants, low-certainty evidence). In the recurrent setting, there was an increase in PFS with the use of anti-EGFR therapy (HR 0.75, 95% CI 0.58 to 0.96, 3 RCTs, 275 participants, low-certainty evidence). The available quality of life assessment data showed that anti-EGFR therapies were neither detrimental or beneficial when compared to standard care (not estimable).

AUTHORS' CONCLUSIONS

In summary, there is no evidence of a demonstrable overall survival benefit with the addition of anti-EGFR therapy in first-line and recurrent glioblastomas. Newer drugs that are specially designed for glioblastoma targets may raise the possibility of success in this population, but data are lacking at present. Future studies should be more selective in pursuing people displaying specific EGFR targets.

Extracellular Vesicle Delivery of TRAIL Eradicates Resistant Tumor Growth in Combination with CDK Inhibition by Dinaciclib

Tumour necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) is a promising anti-cancer agent that rapidly induces apoptosis in cancer cells. Unfortunately, the clinical application of recombinant TRAIL (rTRAIL) has been hampered by its common cancer resistance. Naturally TRAIL is delivered as a membrane-bound form by extracellular vesicles (EV-T) and is highly efficient for apoptosis induction. SCH727965 (dinaciclib), a potent cyclin-dependent kinase (CDK) inhibitor, was shown to synergize with other drugs to get better efficacy. However, it has never been investigated if dinaciclib coordinates with EV-T to enhance therapeutic results. This study explores the potential of combination therapy with EV-T and dinaciclib for cancer treatment. EV-T was successfully derived from human TRAIL transduced cells and shown to partially overcome resistance of A549 cells. Dinaciclib was shown to drastically enhance EV-T killing effects on cancer lines that express good levels of death receptor (DR) 5, which are associated with suppression of CDK1, CDK9 and anti-apoptotic proteins. Combination therapy with low doses of EV-T and dinaciclib induced strikingly enhanced apoptosis and led to complete regression in A549 tumors without any adverse side effects observed in a subcutaneous xenograft model. Tumor infiltration of mass NK cells and macrophages was also observed. These observations thus indicate that the combination of EV-T with dinaciclib is a potential novel therapy for highly effective and safe cancer treatment.

Eosinophil and lymphocyte counts predict bevacizumab response and survival in recurrent glioblastoma

Background

There is a lack of biomarkers to identify glioblastoma (GBM) patients who may benefit from specific salvage therapies, such as the anti-angiogenic agent bevacizumab. We hypothesized that circulating blood counts may serve as biomarkers for treatment response and clinical outcomes.

Methods

Complete blood counts, clinical data, and radiographic information were collected retrospectively from 84 recurrent GBM patients receiving bevacizumab (10 mg/kg every 2 weeks). Significant biomarkers were categorized into quartiles and the association with clinical outcomes was assessed using the Kaplan–Meier method.

Results

The median treatment duration and survival on bevacizumab (OS-A) was 88 and 192 days, respectively. On multivariate analysis, MGMT promoter methylation (hazard ratio [HR] 0.504, P = .031), increases in red blood cells (HR 0.496, P = .035), and increases in eosinophils (HR 0.048, P = .054) during treatment predicted improved OS-A. Patients in the first and fourth quartiles of eosinophil changes had a 12-month survival probability of 5.6% and 41.2% (P < .0001), respectively. Treatment response was associated with increases in eosinophil counts (P = .009) and improved progression-free survival (P = .013). On multivariate analysis, increases in lymphocyte counts among responders predicted improved OS-A (HR 0.389, P = .044). Responders in the first and fourth quartiles of lymphocyte changes had a 12-month survival probability of 0% and 44.4% (P = .019), respectively. Changes in platelet counts differed before and after radiographic response (P = .014).

Conclusions

Changes in circulating eosinophil, lymphocyte, and platelet counts may predict treatment response and clinical outcomes in patients with recurrent GBM receiving bevacizumab.

LncRNA FEZF1-AS1 Sponges miR-34a to Upregulate Notch-1 in Glioblastoma

Introduction

LncRNA FEZF1-AS1 has been reported to be an oncogene in many types of cancer, while its role in glioblastoma (GBM) is unknown. This study aimed to investigate the potential involvement of FEZF1-AS1 in GBM.

Methods

FEZF1-AS1 expression in paired GBM and non-tumor tissues from GBM patients was determined by RT-qPCR. A 2-year follow-up was performed to analyze the prognostic value of FEZF1-AS1 for GBM. Cell transfections were performed to analyze the interactions between FEZF1-AS1, miR-34a and Notch-1. Transwell assay was performed to analyze the role of FEZF1-AS1, miR-34a and Notch-1 in regulating GBM cell invasion and migration.

Results

In this study, analysis of TCGA dataset revealed the upregulation of FEZF1-AS1 in GBM, and the overexpression of FEZF1-AS1 in GBM was further confirmed using GBM tissues from GBM patients included in this study. High levels of FEZF1-AS1 were correlated with poor survival. FEZF1-AS1 was predicted to form base pairing with miR-34a. However, overexpression of FEZF1-AS1 and miR-34a failed to affect the expression of each other. However, upregulation of Notch-1, a target of miR-34a, was observed after FEZF1-AS1 in GBM cells. Moreover, increased invasion and migration rates of GBM cells were observed after FEZF1-AS1 and Notch-1 overexpression. MiR-34a played an opposite role and reduced the effects of FEZF1-AS1 and Notch-1 overexpression.

Conclusion

FEZF1-AS1 may sponge miR-34a to upregulate Notch-1 in GBM, thereby promoting cancer cell invasion and migration.

Engineered scPDL1-DM1 drug conjugate with improved in vitro analysis to target PD-L1 positive cancer cells and intracellular trafficking studies in cancer therapy

Antibody-drug conjugates (ADC), precisely deliver a cytotoxic agent to antigen-expressing tumor cells by using specific binding strategies of antibodies. The ADC has shown the ability of potent bio-therapeutics development but indefinite stoichiometric linkage and full-length antibody penetration compromised the field of its advancement. Single chain variable fragments convention instead of the full-length antibody may overcome the challenge of rapid penetration and internalization. Programmed cell death ligand-1 interaction with PD-1 has recently revolutionized the field of immunotherapy. We systematically designed scPDL1-DM1 drug conjugate by linking scFv-PD-L1 proteins (scFv) with maytansinoids (DM1) cytotoxic agent through succinimidyl trans-4-maleimidylmethyl cyclohexane-1- carboxylate (SMCC) linker. Binding affinity was confirmed by immunocytochemistry, spectrophotometry and gel electrophoresis analysis. The scPDL1-DM1 showed specific binding with PD-L1 positive tumor cells and retained in vitro anti-cell proliferation activity. The intracellular trafficking of the drug was evaluated in A549 cancer cell lines, and maximum trafficking was observed after two hours of incubation. The generated drug can be utilized as a potent tool for site-specific conjugation, predicting specificity in vitro activities with extended range against PD-L1 positive cancer cells and can be utilized for further in vivo testing and clinical therapeutics development.

Unique Case Report of a Meningeal Sarcoma Arising during Ongoing Treatment for Progressing Intraparenchymal Glioma

Radiation-induced sarcomas in the brain are extremely rare, usually occur with an average latency of 9 years, and are associated with poor outcomes. Latency periods shorter than 1 year may indicate a genetic predisposition such as Li-Fraumeni syndrome. A 34-year-old man underwent initial tumor resection and radiation therapy for a World Health Organization (WHO) Grade II Astrocytoma. Within 6 months, the tumor recurred as WHO Grade III and was treated with temozolomide and then bevacizumab. Despite the patient's apparent improving condition, MRI revealed new dural-based lesions 10 months after radiation therapy and identified as high-grade sarcoma. The patient resumed bevacizumab, began NovoTTF treatment for progressing glioma, and ifosfamide/doxorubicin for the sarcoma. Genetic testing revealed no pathogenic mutation in the TP53 gene. Ultimately, treatment was unsuccessful and the patient succumbed to glioma and sarcoma within 2 years of initial diagnosis. This case was unique due to the rapidly progressing glioma and sudden appearance of a high-grade sarcoma. It is unusual to have two separate intracranial primary cancers with each requiring a different chemotherapy regimen. We discuss the difficulty of simultaneously treating with separate chemotherapy regimens. It remains unclear whether the sarcoma was induced by the radiation treatment or a genetic predisposition.

Development of a hybrid nanocarrier-recognizing tumor vasculature and penetrating the BBB for glioblastoma multi-targeting therapy

The success of glioma chemotherapy is hampered by poor drug penetration ability across the blood-brain barrier (BBB) and low intratumoral drug concentration. Novel tumor-targeted delivery systems are useful in specifically accumulating in the tumor foci and penetrating into the glioma core after entering into the brain. Here we show that a multi-targeting hybrid nanocarrier (Pep-MLHA HNPs) system based on hyaluronic acid (HA)-modified polymer and a functional peptide possesses multi-target capability and stronger penetration ability into the core of three-dimensional tumor spheroids, could migrate efficiently across the BBB in vitro. The intensity of the Pep-MLHA HNPs after transporting across the BBB was 5.2-fold and 5.6-fold higher than that of ML NPs in C6 and U87 cells, respectively. More interestingly, this multi-targeting hybrid system displayed high colloidal stability in PBS solution, and weak negative zeta potential (-1.99 ± 0.655 mV) minimizing nonspecific interactions with plasma proteins and promoting long-term circulation in vivo. Additionally, the multi-targeting hybrid system induced enhanced tumor localization in U87 in situ-bearing nude mice and xenograft-bearing nude mice after systemic administration. Furthermore, docetaxel (DTX)-loaded Pep-MLHA HNPs showed negligible systemic toxicity and enhanced therapeutic efficacy, with significantly improved survival rates in intracranial C6 glioma-bearing rats. The 50% survival rate of DTX/Pep-MLHA HNPs-treated rats (40 days) was significantly longer than that of rats treated with NS (22 days), Taxotere® (25 days), DTX/ML NPs (25 days), DTX/Pep NPs (32 days) and DTX/MLHA NPs (29 days). All the results suggested that the multi-targeting hybrid nanocarrier system is promising for glioma treatment.

BRCA1-associated protein inhibits glioma cell proliferation and migration and glioma stem cell self-renewal via the TGF-β/PI3K/AKT/mTOR signalling pathway

PURPOSE

BRCA1-associated protein (BRAP) was first identified by its ability to bind to the nuclear localization signalling motif of BRCA1 and other proteins. Subsequently, human BRAP has been found to exert multiple functions, many of which are related to cancer development. Up till now, however, the role of BRAP in glioma development has remained obscure. Here, we report a role for BRAP in mediating the proliferation and migration of glioma cells both in vitro and in vivo.

METHODS

The expression of BRAP in 98 glioma patient samples was determined by immunohistochemistry, after which associations between BRAP expression and patient prognosis were assessed. A short hairpin RNA (shRNA) was used to knock down BRAP and an expression vector was used to exogenously overexpress BRAP in glioma cells. The effects of BRAP expression on tumour cell behaviour in vitro and in an in vivo xenograft mouse model were examined.

RESULTS

We found that in glioma patients BRAP expression was associated with a favourable prognosis. We also found that shRNA-mediated knockdown of BRAP facilitated the proliferation and migration of glioma cells and the self-renewal of glioma stem cells. In parallel, we found that BRAP knockdown increased tumour growth and invasion and decreased survival in an in vivo glioma xenograft mouse model. Mechanistically, we found that BRAP inhibited glioma cell proliferation and migration, as well as glioma stem cell self-renewal via the TGF-β/PI3K/AKT/mTOR signalling pathway.

CONCLUSIONS

Together, our findings identify BRAP as a mediator of glioma cell proliferation, migration and glioma stem cell self-renewal.

Long non-coding RNA linc00645 promotes TGF-β-induced epithelial-mesenchymal transition by regulating miR-205-3p-ZEB1 axis in glioma

Accumulating evidence indicates long noncoding RNAs (lncRNA) play a vital role in tumor progression. However, the role of linc00645-induced accelerated malignant behavior in glioblastoma (GBM) remains unknown. In the present study, linc00645 expression was significantly upregulated in GBM tissues and cell lines. High level of linc00645 was associated with poor overall survival in GBM patients. Knockdown of linc00645 suppressed the proliferation, stemness, migration, invasion, and reversed transforming growth factor (TGF)-β-induced motility of glioma cell lines. Furthermore, linc00645 directly interacted with miR-205-3p and upregulated of miR-205-3p impeded efficiently the increase of ZEB1 induced by linc00645 overexpression. Moreover, knockdown of linc00645 significantly suppressed the progression of glioma cells in vivo. miR-205-3p was a target of linc00645 and linc00645 modulates TGF-β-induced glioma cell migration and invasion via miR-205-3p. Taken together, our findings identified the linc00645/miR-205-3p/ZEB1 signaling axis as a key player in EMT of glioma cells triggered by TGF-β. These data elucidated that linc00645 plays an oncogenic role in glioma and it may serve as a prognostic biomarker and a potential therapeutic target for the treatment of glioma in humans.

TOPK inhibits autophagy by phosphorylating ULK1 and promotes glioma resistance to TMZ

ULK1, the upper-most protein of the ULK1 complex, is emerging as a crucial node in autophagy induction. However, the regulation of ULK1 is not fully understood. In this study, we identified TOPK (T-LAK cell-originated protein kinase), an oncokinase, as a novel upstream kinase to phosphorylate ULK1. We found that TOPK could directly bind with and phosphorylate ULK1 at Ser469, Ser495, and Ser533. The phosphorylation of ULK1 at Ser469, Ser495, and Ser533 by TOPK decreased the activity and stability of ULK1. In addition, we want to examine the initiation of autophagy because the reduction activity of ULK1 reduces the occurrence of autophagy. We demonstrated that TOPK could inhibit the initiation and progression of autophagy in glioma cells. Furthermore, TOPK inhibition increased the sensitivity of glioma cells to temozolomide (TMZ). This discovery provides insight into the problem of TMZ-resistance in GBM treatment.

Prospective Validation of an Ex Vivo, Patient-Derived 3D Spheroid Model for Response Predictions in Newly Diagnosed Ovarian Cancer

Although 70–80% of newly diagnosed ovarian cancer patients respond to first-line therapy, almost all relapse and five-year survival remains below 50%. One strategy to increase five-year survival is prolonging time to relapse by improving first-line therapy response. However, no biomarker today can accurately predict individual response to therapy. In this study, we present analytical and prospective clinical validation of a new test that utilizes primary patient tissue in 3D cell culture to make patient-specific response predictions prior to initiation of treatment in the clinic. Test results were generated within seven days of tissue receipt from newly diagnosed ovarian cancer patients obtained at standard surgical debulking or laparoscopic biopsy. Patients were followed for clinical response to chemotherapy. In a study population of 44, the 32 test-predicted Responders had a clinical response rate of 100% across both adjuvant and neoadjuvant treated populations with an overall prediction accuracy of 89% (39 of 44, p < 0.0001). The test also functioned as a prognostic readout with test-predicted Responders having a significantly increased progression-free survival compared to test-predicted Non-Responders, p = 0.01. This correlative accuracy establishes the test’s potential to benefit ovarian cancer patients through accurate prediction of patient-specific response before treatment.

Impairing temozolomide resistance driven by glioma stem-like cells with adjuvant immunotherapy targeting O-acetyl GD2 ganglioside

Stem cell chemoresistance remains challenging the efficacy of the front-line temozolomide against glioblastoma. Novel therapies are urgently needed to fight those cells in order to control tumor relapse. Here, we report that anti-O-acetyl-GD2 adjuvant immunotherapy controls glioma stem-like cell-driven chemoresistance. Using patient-derived glioblastoma cells, we found that glioma stem-like cells overexpressed O-acetyl-GD2. As a result, monoclonal antibody 8B6 immunotherapy significantly increased temozolomide genotoxicity and tumor cell death in vitro by enhancing temozolomide tumor uptake. Furthermore, the combination therapy decreased the expression of the glioma stem-like cell markers CD133 and Nestin and compromised glioma stem-like cell self-renewal capabilities. When tested in vivo, adjuvant 8B6 immunotherapy prevented the extension of the temozolomide-resistant glioma stem-like cell pool within the tumor bulk in vivo and was more effective than the single agent therapies. This is the first report demonstrating that anti-O-acetyl-GD2 monoclonal antibody 8B6 targets glioblastoma in a manner that control temozolomide-resistance driven by glioma stem-like cells. Together our results offer a proof of concept for using anti-O-acetyl GD2 reagents in glioblastoma to develop more efficient combination therapies for malignant gliomas.

Efficient development and expression of scFv recombinant proteins against PD-L1 surface domain and potency in cancer therapy

PD-L1 is a 40 kDa trans-membrane protein of B7 family and an important T cell regulator. Binding of PD-L1 and PD-1 inhibits proliferation and activation of T cell results cell exhaustion. This phenomenon can be reversed by blocking PD-L1/PD-1 interactions with single chain variables fragment (scFv) fusion proteins and by direct inhibition of tumor cells with drug conjugates. The human phage-displayed scFv library was utilized to generate scFv against the PD-L1 antigen by affinity bio-panning. The positive clones were selected by continuous transfection of bacterial cells and sequence analysis. The binding affinity and specificity of the scFv and antibody fragments were determined by using surface plasmon resonance biosensor, western blot analysis, and immunofluorescence assay. After three rounds of panning selection, about 30% of clones have a binding affinity with targeted PD-L1 antigen. Eight positive clones with accurate sequences were isolated and analyzed for binding affinity with PD-L1 antigen. Three of those with accurate sequences and binding affinity were selected for the recombinant formation and soluble expression by Escherichia coli host machinery. The highly positive recombinant clones with the exact orientation of FR and CDR domains were developed and can be used as a drug carrier tools in ADC formation or direct inhibition of immune checkpoint in cancer immunotherapy. The conjugate achieved its initial potency and need efficient improvement to enhance direct tumor suppression and bio-therapeutics strategies enrichment.

Decreased let-7b is associated with poor prognosis in glioma

Abnormal expression of let-7b has been observed in many tumors, including glioma. However, the clinical significance of let-7b in glioma remained unclear. The aim of the study was to explore the correlation of let-7b expression with clinicopathological factors and prognosis in human glioma.Quantitative real-time polymerase chain reaction (qRT-PCR) was carried out to detect the relative expression of let-7b in glioma tissues. The association of let-7b expression with clinicopatholoigcal features of glioma patients was estimated using chi-square test. Overall survival curves were plotted using Kaplan-Meier method with log rank test. The prognosis analysis was performed using Cox regression model, and the results were shown as hazard ration (HR) with 95% confidence interval (CI).The relative expression of let-7b was significantly lower in glioma tissues than that in normal brain tissues (P < .001). Furthermore, let-7b level was closely correlated with World Health Organization (WHO) grade (P = .027) and Karnofsky performance score (KPS) (P = .018). Survival analysis indicated that glioma patients with low let-7b expression had significantly shorter overall survival time than those with high expression (log rank test, P < .001). Let-7b might be an independent prognostic biomarker for glioma (P < .001, HR = 2.415; 95% CI: 1.531-3.808).Let-7b may be a promising prognostic factor in glioma.