Glioma therapy in adults

Signaling Pathways of AXL Receptor Tyrosine Kinase Contribute to the Pathogenetic Mechanisms of Glioblastoma

Brain tumors are a diverse collection of neoplasms affecting the brain with a high prevalence rate in people of all ages around the globe. In this pathological context, glioblastoma, a form of glioma that belongs to the IV-grade astrocytoma group, is the most common and most aggressive form of the primary brain tumors. Indeed, despite the best treatments available including surgery, radiotherapy or a pharmacological approach with Temozolomide, glioblastoma patients' mortality is still high, within a few months of diagnosis. Therefore, to increase the chances of these patients surviving, it is critical to keep finding novel treatment opportunities. In the past, efforts to treat glioblastoma have mostly concentrated on customized treatment plans that target specific mutations such as epidermal growth factor receptor (EGFR) mutations, Neurotrophic Tyrosine Receptor Kinase (NTRK) fusions, or multiple receptors using multi-kinase inhibitors like Sunitinib and Regorafenib, with varying degrees of success. Here, we focused on the receptor tyrosine kinase AXL that has been identified as a mediator for tumor progression and therapy resistance in various cancer types, including squamous cell tumors, small cell lung cancer, and breast cancer. Activated AXL leads to a significant increase in tumor proliferation, tumor cell migration, and angiogenesis in different in vitro and in vivo models of cancer since this receptor regulates interplay with apoptotic, angiogenic and inflammatory pathways. Based on these premises, in this review we mainly focused on the role of AXL in the course of glioblastoma, considering its primary biological mechanisms and as a possible target for the application of the most recent treatments.

Molecular signature of stem-like glioma cells (SLGCs) from human glioblastoma and gliosarcoma

Glioblastoma multiforme (GBM) and the GBM variant gliosarcoma (GS) are among the tumors with the highest morbidity and mortality, providing only palliation. Stem-like glioma cells (SLGCs) are involved in tumor initiation, progression, therapy resistance, and relapse. The identification of general features of SLGCs could contribute to the development of more efficient therapies. Commercially available protein arrays were used to determine the cell surface signature of eight SLGC lines from GBMs, one SLGC line obtained from a xenotransplanted GBM-derived SLGC line, and three SLGC lines from GSs. By means of non-negative matrix factorization expression metaprofiles were calculated. Using the cophenetic correlation coefficient (CCC) five metaprofiles (MPs) were identified, which are characterized by specific combinations of 7-12 factors. Furthermore, the expression of several factors, that are associated with GBM prognosis, GBM subtypes, SLGC differentiation stages, or neural identity was evaluated. The investigation encompassed 24 distinct SLGC lines, four of which were derived from xenotransplanted SLGCs, and included the SLGC lines characterized by the metaprofiles. It turned out that all SLGC lines expressed the epidermal growth factor EGFR and EGFR ligands, often in the presence of additional receptor tyrosine kinases. Moreover, all SLGC lines displayed a neural signature and the IDH1 wildtype, but differed in their p53 and PTEN status. Pearson Correlation analysis identified a positive association between the pluripotency factor Sox2 and the expression of FABP7, Musashi, CD133, GFAP, but not with MGMT or Hif1α. Spherical growth, however, was positively correlated with high levels of Hif1α, CDK4, PTEN, and PDGFRβ, whereas correlations with stemness factors or MGMT (MGMT expression and promoter methylation) were low or missing. Factors highly expressed by all SLGC lines, irrespective of their degree of stemness and growth behavior, are Cathepsin-D, CD99, EMMPRIN/CD147, Intβ1, the Galectins 3 and 3b, and N-Cadherin.

The Impact of ROS and NGF in the Gliomagenesis and their Emerging Implications in the Glioma Treatment

Reactive oxygen species (ROS) are highly reactive molecules derived from molecular oxygen (O2). ROS sources can be endogenous, such as cellular organelles and inflammatory cells, or exogenous, such as ionizing radiation, alcohol, food, tobacco, chemotherapeutical agents and infectious agents. Oxidative stress results in damage of several cellular structures (lipids, proteins, lipoproteins, and DNA) and is implicated in various disease states such as atherosclerosis, diabetes, cancer, neurodegeneration, and aging. A large body of studies showed that ROS plays an important role in carcinogenesis. Indeed, increased production of ROS causes accumulation in DNA damage leading to tumorigenesis. Various investigations demonstrated the involvement of ROS in gliomagenesis. The most common type of primary intracranial tumor in adults is represented by glioma. Furthermore, there is growing attention on the role of the Nerve Growth Factor (NGF) in brain tumor pathogenesis. NGF is a growth factor belonging to the family of neurotrophins. It is involved in neuronal differentiation, proliferation and survival. Studies were conducted to investigate NGF pathogenesis's role as a pro- or anti-tumoral factor in brain tumors. It has been observed that NGF can induce both differentiation and proliferation in cells. The involvement of NGF in the pathogenesis of brain tumors leads to the hypothesis of a possible implication of NGF in new therapeutic strategies. Recent studies have focused on the role of neurotrophin receptors as potential targets in glioma therapy. This review provides an updated overview of the role of ROS and NGF in gliomagenesis and their emerging role in glioma treatment.

Systematic Literature Review of Machine Learning Algorithms Using Pretherapy Radiologic Imaging for Glioma Molecular Subtype Prediction

BACKGROUND

The molecular profile of gliomas is a prognostic indicator for survival, driving clinical decision-making for treatment. Pathology-based molecular diagnosis is challenging because of the invasiveness of the procedure, exclusion from neoadjuvant therapy options, and the heterogeneous nature of the tumor.

PURPOSE

We performed a systematic review of algorithms that predict molecular subtypes of gliomas from MR Imaging.

DATA SOURCES

Data sources were Ovid Embase, Ovid MEDLINE, Cochrane Central Register of Controlled Trials, Web of Science.

STUDY SELECTION

Per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 12,318 abstracts were screened and 1323 underwent full-text review, with 85 articles meeting the inclusion criteria.

DATA ANALYSIS

We compared prediction results from different machine learning approaches for predicting molecular subtypes of gliomas. Bias analysis was conducted for each study, following the Prediction model Risk Of Bias Assessment Tool (PROBAST) guidelines.

DATA SYNTHESIS

Isocitrate dehydrogenase mutation status was reported with an area under the curve and accuracy of 0.88 and 85% in internal validation and 0.86 and 87% in limited external validation data sets, respectively. For the prediction of O6-methylguanine-DNA methyltransferase promoter methylation, the area under the curve and accuracy in internal validation data sets were 0.79 and 77%, and in limited external validation, 0.89 and 83%, respectively. PROBAST scoring demonstrated high bias in all articles.

LIMITATIONS

The low number of external validation and studies with incomplete data resulted in unequal data analysis. Comparing the best prediction pipelines of each study may introduce bias.

CONCLUSIONS

While the high area under the curve and accuracy for the prediction of molecular subtypes of gliomas are reported in internal and external validation data sets, limited use of external validation and the increased risk of bias in all articles may present obstacles for clinical translation of these techniques.

Dysregulation of inflammasome activation in glioma

Gliomas are the most common brain tumors characterized by complicated heterogeneity. The genetic, molecular, and histological pathology of gliomas is characterized by high neuro-inflammation. The inflammatory microenvironment in the central nervous system (CNS) has been closely linked with inflammasomes that control the inflammatory response and coordinate innate host defenses. Dysregulation of the inflammasome causes an abnormal inflammatory response, leading to carcinogenesis in glioma. Because of the clinical importance of the various physiological properties of the inflammasome in glioma, the inflammasome has been suggested as a promising treatment target for glioma management. Here, we summarize the current knowledge on the contribution of the inflammasomes in glioma and therapeutic insights. Video Abstract.

Non-canonical NLRC4 inflammasomes in astrocytes contribute to glioma malignancy

BACKGROUND

The present study was designed to explore the pathological role of non-canonical NLRC4 inflammasome in glioma.

METHODS

This retrospective study included bioinformatical analysis, including survival, gene ontology, ssGSEA, cox regression, IPA and drug repositioning with TCGA and DepMap database. Experimental validations were conducted in glioma patient's sample and evaluated with histological or cellular functional analysis.

RESULT

Clinical dataset analysis revealed that non-canonical NLRC4 inflammasomes significantly contribute to glioma progression and poor survival rates. Experimental validation was revealed that the expression of non-canonical NLRC4 inflammasomes were co-localized with astrocytes in malignant gliomas, with a sustained clinical correlation observed between astrocytes and inflammasome signatures. Indeed, the formation of an inflammatory microenvironment increased in malignant gliomas, leading to pyroptosis, known as inflammatory cell death. Molecular interaction analysis revealed that NF-κB pathways potentially serve as the connecting point between the canonical and noncanonical pathways of the NLRC4 inflammasome. Finally, drug repositioning analysis of non-canonical NLRC4 inflammasome-associated molecules revealed that MK-5108, PF4981517, and CTEP may represent effective options for glioma therapy.

CONCLUSION

The findings of this study suggest that non-canonical NLRC4 inflammasomes contribute to poor prognosis in patients with glioma and induce an inflammatory microenvironment. We propose the pathological phenomenon of non-canonical NLRC4 inflammasomes and several therapeutic strategies based on the modulation of the inflammatory tumor microenvironment.

Nomogram Model for Predicting the Prognosis of High-Grade Glioma in Adults Receiving Standard Treatment: A Retrospective Cohort Study

OBJECTIVES

To identify the critical factors associated with the progression-free survival (PFS) and overall survival (OS) of high-grade glioma (HGG) in adults who have received standard treatment and establish a novel graphical nomogram and an online dynamic nomogram.

PATIENTS AND METHODS

This is a retrospective study of adult HGG patients receiving standard treatment (surgery, postoperative radiotherapy, and temozolomide (TMZ) chemotherapy) at Huashan Hospital, Fudan University between January 2017 and December 2019. We used uni- and multi-variable COX models to identify the significant prognostic factors for PFS and OS. Based on the significant predictors, graphical and online nomograms were established.

RESULTS

A total of 246 patients were enrolled in the study based on the inclusion criteria. The average PFS and OS were 22.99 ± 11.43 and 30.51 ± 13.73 months, respectively. According to the multi-variable COX model, age, extent of resection (EOR), and IDH mutation were associated with PFS and OS, while edema index (EI) was relevant to PFS. In addition, patients with IDH and TERT promoter co-mutations had longer PFSs and OSs, and no apparent survival benefit was found in the long-cycle TMZ adjuvant chemotherapy compared with the standard Stupp protocol. Based on these critical factors, a graphical nomogram and online nomogram were developed for predicting PFS and OS, respectively. The calibration curve showed favorable consistency between the predicted and actual survival rates. C-index and time-dependent AUC showed good discrimination abilities.

CONCLUSIONS

We identified the significant predictors for the PFS and OS of HGG adults receiving standard treatment and established user-friendly nomogram models to assist neurosurgeons in optimizing clinical management and treatment strategies.

Transcriptome Analysis and Single-Cell Sequencing Analysis Constructed the Ubiquitination-Related Signature in Glioma and Identified USP4 as a Novel Biomarker

Background

Glioma, the most frequent malignant tumor of the neurological system, has a poor prognosis and treatment problems. Glioma’s tumor microenvironment is also little known.

Methods

We downloaded glioma data from the TCGA database. The patients in the TCGA database were split into two groups, one for training and the other for validation. The ubiquitination genes were then evaluated in glioma using COX and Lasso regression to create a ubiquitination-related signature. We assessed the signature’s predictive usefulness and role in the immune microenvironment after it was generated. Finally, in vitro experiment were utilized to check the expression and function of the signature’s key gene, USP4.

Results

This signature can be used to categorize glioma patients. Glioma patients can be separated into high-risk and low-risk groups in both the training and validation cohorts, with the high-risk group having a significantly worse prognosis (P<0.05). Following further investigation of the immune microenvironment, it was discovered that this risk grouping could serve as a guide for glioma immunotherapy. The activity, invasion and migration capacity, and colony formation ability of U87-MG and LN229 cell lines were drastically reduced after the important gene USP4 in signature was knocked down in cell tests. Overexpression of USP4 in the A172 cell line, on the other hand, greatly improved clonogenesis, activity, invasion and migration.

Conclusions

Our research established a foundation for understanding the role of ubiquitination genes in gliomas and identified USP4 as a possible glioma biomarker.

Drug Delivery Systems in the Development of Novel Strategies for Glioblastoma Treatment

Glioblastoma multiforme (GBM) is a grade IV glioma considered the most fatal cancer of the central nervous system (CNS), with less than a 5% survival rate after five years. The tumor heterogeneity, the high infiltrative behavior of its cells, and the blood-brain barrier (BBB) that limits the access of therapeutic drugs to the brain are the main reasons hampering the current standard treatment efficiency. Following the tumor resection, the infiltrative remaining GBM cells, which are resistant to chemotherapy and radiotherapy, can further invade the surrounding brain parenchyma. Consequently, the development of new strategies to treat parenchyma-infiltrating GBM cells, such as vaccines, nanotherapies, and tumor cells traps including drug delivery systems, is required. For example, the chemoattractant CXCL12, by binding to its CXCR4 receptor, activates signaling pathways that play a critical role in tumor progression and invasion, making it an interesting therapeutic target to properly control the direction of GBM cell migration for treatment proposes. Moreover, the interstitial fluid flow (IFF) is also implicated in increasing the GBM cell migration through the activation of the CXCL12-CXCR4 signaling pathway. However, due to its complex and variable nature, the influence of the IFF on the efficiency of drug delivery systems is not well understood yet. Therefore, this review discusses novel drug delivery strategies to overcome the GBM treatment limitations, focusing on chemokines such as CXCL12 as an innovative approach to reverse the migration of infiltrated GBM. Furthermore, recent developments regarding in vitro 3D culture systems aiming to mimic the dynamic peritumoral environment for the optimization of new drug delivery technologies are highlighted.

Knockdown of circ_0055412 promotes cisplatin sensitivity of glioma cells through modulation of CAPG and Wnt/β-catenin signaling pathway

INTRODUCTION

Glioma is the most frequent primary cerebral tumor in adults. Recent evidence has suggested that circular RNAs (circRNAs) are associated with the pathological processes in glioma. In our study, we aimed to investigate the function and mechanism of circ_CAPG (circ_0055412) in glioma.

METHODS

Firstly, circ_0055412 expression was examined through RT-qPCR analysis. Loss-of-function assays and animal experiments were implemented to evaluate the role of circ_0055412 on cisplatin resistance of glioma cells. Moreover, mechanism assays were done to probe into the regulatory mechanism of circ_0055412 in glioma cells.

RESULTS

Circ_0055412 was found to be notably upregulated in glioma cells. Moreover, depletion of circ_0055412 enhanced cisplatin sensitivity of glioma cells in vitro and in vivo. Moreover, circ_0055412 recruited eukaryotic translation initiation factor 4A3 (EIF4A3) protein to stabilize capping actin protein, gelsolin like (CAPG) mRNA. Furthermore, circ_0055412 served as a sponge for microRNA-330-3p (miR-330-3p) and regulated nuclear factor of activated T cells 3 (NFATC3) expression to activate the transcription of catenin beta 1 (CTNNB1), thus participating in the activation of Wnt/β-catenin signaling pathway.

CONCLUSION

Circ_0055412 contributed to cisplatin resistance of glioma cells via stabilizing CAPG mRNA and modulating Wnt/β-catenin signaling pathway. This finding might provide novel information for the treatment of glioma.

ZNF655 Promotes the Progression of Glioma Through Transcriptional Regulation of AURKA

Objectives

Glioma has a high degree of malignancy, strong invasiveness, and poor prognosis, which is always a serious threat to human health. Previous studies have reported that C2H2 zinc finger (ZNF) protein is involved in the progression of various cancers. In this study, the clinical significance, biological behavior, and molecule mechanism of ZNF655 in glioma were explored.

Methods

The expression of ZNF655 in glioma and its correlation with prognosis were analyzed through public datasets and immunohistochemical (IHC) staining. The shRNA-mediated ZNF655 knockdown was used to explore the effects of ZNF655 alteration on the phenotypes and tumorigenesis of human glioma cell lines. Chromatin immunoprecipitation (ChIP)-qPCR and luciferase reporter assays were performed to determine the potential mechanism of ZNF655 regulating Aurora kinase A (AURKA).

Results

ZNF655 was abundantly expressed in glioma tissue and cell lines SHG-44 and U251. Knockdown of suppressed the progression of glioma cells, which was characterized by reduced proliferation, enhanced apoptosis, cycle repression in G2, inhibition of migration, and weakened tumorigenesis. Mechanistically, transcription factor ZNF655 activated the expression of AURKA by directly binding to the promoter of AURKA. In addition, downregulation of AURKA partially reversed the promoting effects of overexpression of ZNF655 on glioma cells.

Conclusions

ZNF655 promoted the progression of glioma by binding to the promoter of AURKA, which may be a promising target for molecular therapy.

COP1 Acts as a Ubiquitin Ligase for PCDH9 Ubiquitination and Degradation in Human Glioma

Constitutive photomorphogenic 1 (COP1, also known as RFWD2), a ring-finger-type E3 ubiquitin ligase, has been reported to play a pivotal role in the regulation of cell growth, apoptosis, and DNA repair. Accumulating evidence has suggested that COP1 plays a role in tumorigenesis by triggering the ubiquitination and degradation of its substrates, but the potential mechanism remains unclear. In this study, COP1 was used as a bait in a yeast two-hybrid experiment to screen COP1-interacting proteins in a human brain cDNA library, and the results indicated that protocadherin 9 (PCDH9) was a potential binding protein of COP1. The interaction between and colocalization of COP1 and PCDH9 was further confirmed by coimmunoprecipitation (co-IP) assay and immunofluorescent staining. Subsequently, we demonstrated that COP1 acted as an E3 ligase to promote the ubiquitination and degradation of PCDH9 through the proteasome pathway in glioma cells. Furthermore, we identified that the type of COP1 mediated PCDH9 ubiquitination was Lys⁴⁸-linked polyubiquitination. Finally, we found that the COP1 protein level was inversely correlated with the PCDH9 protein level in human glioma tissues. Taken together, our results suggest that COP1 is an E3 ubiquitin ligase for PCDH9 and reveal an important mechanism for PCDH9 regulation in human glioma.

MAP3K8 Is a Prognostic Biomarker and Correlated With Immune Response in Glioma

MAP3K8 is a serine/threonine kinase that is widely expressed in immune cells, non-immune cells, and many tumor types. The expression, clinical significance, biological role, and the underlying molecular mechanisms of MAP3K8 in glioma have not been investigated yet. Here, we discovered that MAP3K8 was aberrantly overexpressed in glioma and correlated with poor clinicopathological features of glioma by analysis on different datasets and immunohistochemistry staining. MAP3K8 is an independent prognostic indicator and significantly correlates with the progression of glioma. We also performed the function and pathway enrichment analysis of MAP3K8 in glioma to explore its biological functions and underlying molecular mechanisms in glioma. MAP3K8 co-expressed genes were mainly enriched in immune-related biological processes such as neutrophil activation, leukocyte migration, neutrophil-mediated immunity, lymphocyte-mediated immunity, T-cell activation, leukocyte cell–cell adhesion, regulation of leukocyte cell–cell adhesion, B-cell-mediated immunity, myeloid cell differentiation, and regulation of cell–cell adhesion. Single-cell RNA sequencing data and immunohistochemistry analysis demonstrated that MAP3K8 is expressed in malignant and immune cells and mainly enriched in the microglia/macrophage cells of glioma. The expression of MAP3K8 was positively correlated with immune infiltration, including effector memory CD4⁺ T cells, plasmacytoid dendritic cells, neutrophils, myeloid dendritic cells, mast cells, and macrophage in glioma. Further correlation analysis demonstrated that a series of inhibitory immune checkpoint molecules, chemokines, and chemokine receptors was positively correlated with the expression of MAP3K8. MAP3K8 might play an essential role in tumor immunity, and inhibition of MPA3K8 is a plausible strategy for glioma immunotherapy.

Fraxetin exerts anticancer effect in glioma by suppressing MiR-21-3p

Fraxetin (FXT) exerts anticancer function in multiple cancers, but its function on glioma was ill-defined. This article expounded the mechanism by which FXT exerts an anticancer effect in glioma. The effect of gradient concentration of FXT on the viability of glioma cell lines was determined by cell counting kit 8. Effects of FXT on proliferation, apoptosis, and cell cycle in glioma cell lines were determined by colony formation assay, flow cytometry, and Hoechst 33342 staining. Expressions of apoptosis-related gene, cycle-related gene, and glioma-related miRNAs after FXT (25 and 50 μmol/L) treatment were determined by quantitative reverse transcription polymerase chain reaction and western blot as needed. After miR-21-3p overexpression, cell viability and apoptosis of glioma cell lines treated with FXT (50 μmol/L) were tested again. Although 1 μmol/L FXT had no significant effect on cell viability, 5, 10, 25, and 50 μmol/L FXT suppressed cell viability in a concentration-dependent manner. FXT inhibited proliferation, promoted apoptosis, and induced cell cycle arrest in G0/G1 phase in glioma cell lines. These effects may be achieved by elevated expressions of Bax and cleaved caspase-3 and diminished expressions of Bcl-2, Bcl-XL, cyclin E1, cyclin D1, and cyclin-dependent kinase-6. FXT attenuated the contents of miR-21-3p and miR-455-3p, and escalated the contents of miR-124-3p and miR-7-5p. The regulation of FXT on cell viability, proliferation and apoptosis was reversed by miR-21-3p overexpression. FXT suppressed the development of glioma cells by downregulating miR-21-3p.

The Roles Played by Long Non-Coding RNAs in Glioma Resistance

Glioma originates in the central nervous system and is classified based on both histological features and molecular genetic characteristics. Long non-coding RNAs (lncRNAs) are longer than 200 nucleotides and are known to regulate tumorigenesis and tumor progression, and even confer therapeutic resistance to glioma cells. Since oncogenic lncRNAs have been frequently upregulated to promote cell proliferation, migration, and invasion in glioma cells, while tumor-suppressive lncRNAs responsible for the inhibition of apoptosis and decrease in therapeutic sensitivity in glioma cells have been generally downregulated, the dysregulation of lncRNAs affects many features of glioma patients, and the expression profiles associated with these lncRNAs are needed to diagnose the disease stage and to determine suitable therapeutic strategies. Accumulating studies show that the orchestrations of oncogenic lncRNAs and tumor-suppressive lncRNAs in glioma cells result in signaling pathways that influence the pathogenesis and progression of glioma. Furthermore, several lncRNAs are related to the regulation of therapeutic sensitivity in existing anticancer therapies, including radiotherapy, chemotherapy and immunotherapy. Consequently, we undertook this review to improve the understanding of signaling pathways influenced by lncRNAs in glioma and how lncRNAs affect therapeutic resistance.

The value of quantitative pentavalent 99mTc-dimercaptosuccinic acid scan in predicting progression-free survival and overall survival in patients with glioblastoma multiforme

Aim:

Glioblastoma multiforme (GBM) is the commonest and the most aggressive primary brain tumour. Pentavalent 99mTc-dimercaptosuccinic acid (99mTc (V)-DMSA) has been found to be a tumour-seeking agent. Pre-radiotherapy 99mTc (V)-DMSA positive scan was found to be significantly correlated with poor progression-free survival (PFS) and overall survival (OS). This study aims at evaluating the impact of quantitative 99mTc (V)-DMSA tumour uptake before and after radiotherapy on PFS and OS in patients with GBM.

Methods:

A prospective study included 40 patients with GBM. Single-photon emission computed tomography studies were done before and after adjuvant radiotherapy and were qualitatively and quantitatively evaluated. The retention index (RI) of the viable tumour was correlated with PFS and OS.

Results:

The qualitative enhancement of 99mTc (V)-DMSA uptake either positive or negative was significantly correlated with PFS at both early and late images (p-values 0·04 and 0·026, respectively) and OS only in the late image (p-value 0·036). The calculated ion/non-lesion ratios at late images were statistically correlated with PFS and OS (p-values 0·021 and 0·025, respectively). The baseline RI had significant correlation with PFS only (p-value 0·01).

Conclusion:

The degree of 99mTc (V)-DMSA scan positivity is a poor prognostic factor for PFS and OS in GBM patients.

Intracranial 131I-chTNT Brachytherapy in Patients with Deep-Seated Glioma: A Single-center Experience with 10-Year Follow-up from China

OBJECTIVE

 The intracranial brachytherapy has been applied for decades, however, no results with long-term follow-up have been reported. This study investigated the long-term efficiency of intra-tumoral injection of ¹³¹I-chTNT in patients with deep-seated glioma.

METHOD

 Thirty-five patients undergoing ¹³¹I-chTNT brachytherapy between December 2004 and May 2009 were enrolled. ¹³¹I-chTNT was injected at a dose of 1.5 mCi/cm³ at an interval of 1 month for consecutive 3 times. Serial ECT scan and MRI were performed during follow-up. Progression-free survival (PFS) and overall survival (OS) were analyzed. Adverse reactions were graded with WHO Toxicity Grading Scale for determining the severity of adverse events.

RESULTS

 ECT scan showed that enhanced accumulation of radioactive agents in the tumor lasted for more than 30 days. Three months after final injection, tumor complete remission (CR) was observed in 4 patients (11.4 %), partial remission (PR) in 11 cases (31.4 %), stable disease (SD) in 10 cases (28.6 %) and progressive disease (PD) in 10 cases (28.6 %). At 6-month, CR, PR, SD and PD were 2, 6, 12 and 15 respectively. After 10 years of follow-up, median progression-free survival (PFS) and overall survival (OS) were 5.4 and 11.4 months. One-year survival was 45.7 %, two and five-year survival was 8.6 %, ten-year survival was 5.7 %. Multivariate analysis showed that pathological grade and tumor diameter were independent prognostic factors for PFS and OS. Grade I-II adverse events occurred after drug injection, including nausea, fever, headache, hairloss and fatigue.

CONCLUSION

 ¹³¹I-chTNT intracranial brachytherapy is efficient and safe for patients with deep-seated glioma. It is a reliable option for inoperable glioma patients.

Monitoring Early Changes in Tumor Metabolism in Response to Therapy Using Hyperpolarized 13C MRSI in a Preclinical Model of Glioma

This study shows the use of hyperpolarized ¹³C magnetic resonance spectroscopic imaging (MRSI) to assess therapeutic efficacy in a preclinical tumor model. ¹³C-labeled pyruvate was used to monitor early changes in tumor metabolism based on the Warburg effect. High-grade malignant tumors exhibit increased glycolytic activity and lactate production to promote proliferation. A rodent glioma model was used to explore altered lactate production after therapy as an early imaging biomarker for therapeutic response. Rodents were surgically implanted with C6 glioma cells and separated into 4 groups, namely, no therapy, radiotherapy, chemotherapy and combined therapy. Animals were imaged serially at 6 different time points with magnetic resonance imaging at 3 T using hyperpolarized [1-¹³C]pyruvate MRSI and conventional ¹H imaging. Using hyperpolarized [1-¹³C]pyruvate MRSI, alterations in tumor metabolism were detected as changes in the conversion of lactate to pyruvate (measured as Lac/Pyr ratio) and compared with the conventional method of detecting therapeutic response using the Response Evaluation Criteria in Solid Tumors. Moreover, each therapy group expressed different characteristic changes in tumor metabolism. The group that received no therapy showed a gradual increase of Lac/Pyr ratio within the tumor. The radiotherapy group showed large variations in tumor Lac/Pyr ratio. The chemo- and combined-therapy groups showed a statistically significant reduction in tumor Lac/Pyr ratio; however, only combined therapy was capable of suppressing tumor growth, which resulted in low endpoint mortality rate. Hyperpolarized ¹³C MRSI detected a prompt reduction in Lac/Pyr ratio as early as 2 days post combined chemo- and radiotherapies.

Polymeric Nanoparticles for the Treatment of Malignant Gliomas

Malignant gliomas are one of the deadliest forms of brain cancer and despite advancements in treatment, patient prognosis remains poor, with an average survival of 15 months. Treatment using conventional chemotherapy does not deliver the required drug dose to the tumour site, owing to insufficient blood brain barrier (BBB) penetration, especially by hydrophilic drugs. Additionally, low molecular weight drugs cannot achieve specific accumulation in cancerous tissues and are characterized by a short circulation half-life. Nanoparticles can be designed to cross the BBB and deliver their drugs within the brain, thus improving their effectiveness for treatment when compared to administration of the free drug. The efficacy of nanoparticles can be enhanced by surface PEGylation to allow more specificity towards tumour receptors. This review will provide an overview of the different therapeutic strategies for the treatment of malignant gliomas, risk factors entailing them as well as the latest developments for brain drug delivery. It will also address the potential of polymeric nanoparticles in the treatment of malignant gliomas, including the importance of their coating and functionalization on their ability to cross the BBB and the chemistry underlying that.

Biological Functions of TNKS1 and Its Relationship with Wnt/β-Catenin Pathway in Astrocytoma

Background

Tankyrase1 (TNKS1), which often shows abnormal expression in many malignant tumor cells, plays an important role in tumor progression. In our previous study, we found that TNKS1 is also closely related to pathologic grade in human astrocytoma and its expression level is positively correlated with the Wnt/β-catenin pathway. This study is aimed to further elucidate the biological functions of TNKS1 as well as its relationship with the Wnt/β-catenin pathway.

Methods

TNSK1 overexpression and knockdown vectors were constructed and transfected into glioblastoma cell lines U251 MG and U87, respectively. Viability, apoptosis, cell cycle and cell invasiveness in the treated cells were investigated.

Results

In comparison with untreated cells, U251 and U87 cells overexpressing TNSK1 showed significantly increased cell viability and decreased apoptosis, while the TNKS1 knockdown U251 and U87 cells had reduced cell invasive ability and increased apoptosis, respectively. In addition, immunoprecipitation study showed that TNKS1 could be detected by β-catenin antibody after pull-down, indicating that TNKS1 directly interacts with β-catenin, further indicating that TNKS1 could be regarded as a positive regulator of the Wnt/β-catenin pathway in astrocytoma. Moreover, knockdown of TNKS1 in U251 and U87 cells also leads to suppressed Wnt/β-catenin signaling, and subsequent decrease of cell growth and proliferation, reduced invasion ability and increased apoptosis.

Conclusion

Our findings suggest that TNKS1 might be a potential new therapeutic target for human astrocytoma in gene therapy.

SMAD3 silencing enhances DNA damage in radiation therapy by interacting with MRE11-RAD50-NBS1 complex in glioma

Radiotherapy is the major treatment modality for malignant glioma. However, the treatment response of radiotherapy is suboptimal due to resistance. Here we aimed to explore the effect and mechanism of Mothers against decapentaplegic homologue (SMAD3) silencing in sensitizing malignant glioma to radiotherapy. Clonogenic assay was used to evaluate the sensitivity of glioma cells to increasing doses of radiation. Glioma cells were transfected with small-interfering RNAs (siRNAs) specific to SMAD3. Overexpression of SMAD3 was achieved by transfecting expression plasmid encoding SMAD3 cDNA. Changes in MRE11-RAD50-NBS1 mRNA and protein levels were assessed through qPCR analysis and western blot analysis, respectively. Chromatin immunoprecipitation (ChIP) was used to confirm the interaction between SMAD3 and MRE11-RAD50-NBS1 (MRN) complex. Silencing of SMAD3 increased sensitivity of glioma cells to radiotherapy. MRE11, RAD50 and NBS1 were overexpressed in response to radiotherapy, which was attenuated by SMAD3 silencing while boosted by SMAD3 overexpression. ChIP analysis confirmed the interaction of SMAD3 with MRE11, RAD50 and NBS1 under radiotherapy, which was inhibited by SMAD3 silencing. SMAD3 silencing is an effective strategy for sensitizing glioma to radiotherapy, which is mediated by the interaction of SMAD3 with the MRN complex.

Survival Analysis of Glioblastoma Multiforme

Introduction:

To evaluate the survival of Glioblastoma Multiforme (GBM).

Material and Methods:

Patients with a pathological diagnosis of Glioblastoma Multiforme (GBM) between 1 January 1994 and 30 November 2013, were retrospectively reviewed. Inclusion criteria: 1) GBM patients with confirmed pathology, 2) GBM patients were treated by multimodality therapy. Exclusion criteria: 1) GBM patients with unconfirmed pathology, 2) GBM patients with spinal involvement, 3) GBM patients with incomplete data records. Seventy-seven patients were treated by multimodality therapy such as surgery plus post-operative radiotherapy (PORT), post-operative Temozolomide (TMZ) concurrent with radiotherapy (CCRT), post-operative CCRT with adjuvant TMZ. The overall survival was calculated by the Kaplan-Meier method and the log-rank test was used to compare the survival curves. A p-value of ≤ 0.05 was considered to be statistically significant.

Results:

Seventy-seven patients with a median age of 53 years (range 4-76 years) showed a median survival time (MST) of 12 months. In subgroup analyses, the PORT patients revealed a MST of 11 months and 2 year overall survival (OS) rates were 17.2%, the patients with post-operative CCRT with or without adjuvant TMZ revealed a MST of 23 months and 2 year OS rates were 38.2%. The MST of patients by Recursive Partitioning Analysis (RPA), classifications III, IV, V, VI were 26.8 months, 14.2 months, 9.9 months, and 4.0 months, (p <0.001).

Conclusions:

The MST of the patients who had post-operative CCRT with or without adjuvant TMZ was better than the PORT group. The RPA classification can be used to predict survival. Multimodality therapy demonstrated the most effective treatment outcome. Temozolomide might be beneficial for GBM patients in order to increase survival time.

Escitalopram oxalate induces apoptosis in U-87MG cells and autophagy in GBM8401 cells

Glioblastoma multiforme (GBM) is recognized as a most aggressive brain cancer with the worst prognosis and survival time. Owing to the anatomic location of gliomas, surgically removing the tumour is very difficult and avoiding damage to vital brain regions during radiotherapy is impossible. Therefore, therapeutic strategies for malignant glioma must urgently be improved. Recent studies have demonstrated that selective serotonin reuptake inhibitors (SSRIs) have cytotoxic effect on certain cancers. Considering as a more superior SSRI, escitalopram oxalate exhibits favourable tolerability and causes generally mild and temporary adverse events. However, limited information is revealed about the influence of escitalopram oxalate on GBM. Therefore, an attempt was made herein to explore the effects of escitalopram oxalate on GBM. The experimental results revealed that escitalopram oxalate significantly inhibits the proliferation and invasive ability of U‐87MG cells and significantly reduced the expressions of cell cycle inhibitors such as Skp2, P57, P21 and P27. Notably, escitalopram oxalate also induced significant apoptotic cascades in U‐87MG cells and autophagy in GBM8401 cells. An animal study indicated that escitalopram oxalate inhibits the proliferation of xenografted glioblastoma in BALB/c nude mice. These findings implied that escitalopram oxalate may have potential in treatment of glioblastomas.

Identification of a gene signature associated with radiotherapy and prognosis in gliomas

Glioma is one of the most common primary brain tumors with poor prognosis. Although radiotherapy is an important treatment method for gliomas, the efficacy is still limited by the high occurrence of radioresistance and the underlying molecular mechanism is unclear. Here, we performed a data mining work based on four glioma expression datasets. These datasets were classified into training set and validation set. Radiotherapy-induced differential expressed genes and prognosis-associated genes were screened using different classifiers. The Kaplan-Meier curves along with the two-sided Log Rank (Mantel-Cox) test were used to evaluate overall survival. We found the gene expression profiles of gliomas between those patients received radiotherapy and those patients without received radiotherapy were quite different. A 20-gene signature was identified, which was associated with radiotherapy.Furthermore, a novel 5-gene signature (HOXC10, LOC101928747, CYB561D2, RPL36A and RPS4XP2) as an independent predictor of glioma patients’ prognosis was further derived from the 20-gene signature. These findings provided a new insight into the molecular mechanism of radioresistance in gliomas. The 5-gene signature might represent therapeutic target for gliomas.

Mathematical Analysis of Glioma Growth in a Murine Model

Five immunocompetent C57BL/6-cBrd/cBrd/Cr (albino C57BL/6) mice were injected with GL261-luc2 cells, a cell line sharing characteristics of human glioblastoma multiforme (GBM). The mice were imaged using magnetic resonance (MR) at five separate time points to characterize growth and development of the tumor. After 25 days, the final tumor volumes of the mice varied from 12 mm³ to 62 mm³, even though mice were inoculated from the same tumor cell line under carefully controlled conditions. We generated hypotheses to explore large variances in final tumor size and tested them with our simple reaction-diffusion model in both a 3-dimensional (3D) finite difference method and a 2-dimensional (2D) level set method. The parameters obtained from a best-fit procedure, designed to yield simulated tumors as close as possible to the observed ones, vary by an order of magnitude between the three mice analyzed in detail. These differences may reflect morphological and biological variability in tumor growth, as well as errors in the mathematical model, perhaps from an oversimplification of the tumor dynamics or nonidentifiability of parameters. Our results generate parameters that match other experimental in vitro and in vivo measurements. Additionally, we calculate wave speed, which matches with other rat and human measurements.

Long noncoding RNA FTX is upregulated in gliomas and promotes proliferation and invasion of glioma cells by negatively regulating miR-342-3p

Gliomas remain a major public health challenge, posing a high risk for brain tumor-related morbidity and mortality. However, the mechanisms that drive the development of gliomas remain largely unknown. Emerging evidence has shown that long noncoding RNAs are key factors in glioma pathogenesis. qRT-PCR analysis was used to assess the expression of FTX and miR-342-3p in the different stages of gliomas in tissues. Bioinformatics tool DIANA and TargetSCan were used to predict the targets of FTX and miR-342-3p, respectively. Pearson's correlation analysis was performed to test the correlation between the expression levels of FTX, miR-342-3p, and astrocyte-elevated gene-1 (AEG-1). To examine the role of FTX in regulating proliferation and invasion of glioma cells, specific siRNA was used to knockdown FTX, and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and transwell assays were performed. Furthermore, rescue experiments were performed to further confirm the regulation of miR-342-3p by FTX. We then found that the expression of FTX and miR-342-3p was associated with progression of gliomas. FTX directly inhibited the expression of miR-342-3p, which subsequently regulates the expression of AEG-1. Collectively, FTX is critical for proliferation and invasion of glioma cells by regulating miR-342-3p and AEG-1. Our findings indicate that FTX and miR-342-3p may serve as a biomarker of glioma diagnosis, and offer potential novel therapeutic targets of treatment of gliomas.

Glioblastoma Multiforme: A Review of its Epidemiology and Pathogenesis through Clinical Presentation and Treatment

Glioblastoma multiforme (GBM) is one of the most malignant types of central nervous system tumors. Despite advances in treatment modalities it remains largely incurable. The objective of our review is to provide a holistic picture of GBM epidemiology, etiology, pathogenesis, clinical findings and treatment. A literature search was conducted for GBM at PubMed and Google Scholar, with relevant key words like glioblastoma multiforme, pathogenesis, signs and symptoms, treatment etc., and papers published until 2015 were reviewed. It was found that radiation and certain genetic syndromes are the only risk factors identified to date for GBM. Depending on the tumor site patients may present to the clinic with varying symptoms. To confirm the presence and the extent of tumor, various invasive and non-invasive imaging techniques require employment. The literature survey revealed the pathogenesis to involve aberrations of multiple signaling pathways through multiple genetic mutations and altered gene expression. Although several treatment options are available, including surgery, along with adjuvant chemo- and radio-therapy, the disease has a poor prognosis and patients generally succumb within 14 months of diagnosis.

Vascular Targeted Radioimmunotherapy for the Treatment of Glioblastoma

Glioblastoma is characterized by an aggressive and aberrant vascular network that promotes tumor progression and hinders effective treatment; the median survival is 16 mo despite standard-of-care therapies. There is a need to improve therapeutic options for this disease. We hypothesized that antibody targeting of the vascular endothelium of glioblastoma with cytotoxic short-range, high-energy α-particles would be an effective therapeutic approach.

METHODS

E4G10, an antibody directed at an epitope of monomeric vascular endothelium cadherin that is expressed in tumor neovasculature and on endothelial progenitor cells in the bone marrow, was labeled with α-particle-emitting ²²⁵Ac. Pharmacokinetic studies investigated the tissue distribution and blood clearance of the ²²⁵Ac-E4G10 radioimmunoconstruct in a transgenic Nestin-tumor virus A (Ntva) mouse model of high-grade glioblastoma. Histologic analysis was used to demonstrate local therapeutic effects in treated brain tumor sections. Radioimmunotherapy with ²²⁵Ac-E4G10 was performed in Ntva mice to assess overall survival alone and in combination with temozolomide, the standard-of-care chemotherapeutic agent.

RESULTS

²²⁵Ac-E4G10 was found to accumulate in tissues expressing the target antigen. Antivascular α-particle therapy of glioblastoma in the transgenic Ntva model resulted in significantly improved survival compared with controls and potent control of tumor growth. Adding the chemotherapeutic temozolomide to the treatment increased survival to 30 d (vs. 9 d for vehicle-treated animals). Histologic analyses showed a remodeled glioblastoma vascular microenvironment.

CONCLUSION

Targeted α-particle antivascular therapy is shown for the first time to be effective in increasing overall survival in a solid tumor in a clinically relevant transgenic glioblastoma mouse model.

Feasibility of the Combined Application of Navigated Probabilistic Fiber Tracking and Navigated Ultrasonography in Brain Tumor Surgery

BACKGROUND

Surgical resection of intra-axial tumors is a challenging procedure because of indistinct tumor margins, infiltration, and displacement of white matter tracts surrounding the lesion. Hence, gross total tumor resection without causing new neurologic deficits is demanding, especially in tumor sites adjoining eloquent structures. Feasibility of the combination of navigated probabilistic fiber tracking to identify eloquent fiber pathways and navigated ultrasonography to control brain shift was tested.

METHODS

Eleven patients with lesions adjacent to eloquent white matter structures (pyramidal tract, optic radiation and arcuate fascicle) were preoperatively subjected to magnetic resonance imaging including diffusion-weighted imaging on a 3-T magnetic resonance system (Trio [Siemens, Erlangen, Germany]). Probabilistic fiber tracking was performed using the tools of the FMRIB Software Library (FSL). Results of probabilistic fiber tracking and high-resolution anatomic images were integrated into the neuronavigation system Stealth Station (Medtronic, Minneapolis, Minnesota, USA) together with the navigated ultrasonography (SonoNav [Medtronic]).

RESULTS

FSL-based probabilistic fiber tracking depicted the pyramidal tract, the optic radiation, and arcuate fascicle anatomically plausibly. Integration of the probabilistic fiber tracking into neuronavigation was technically feasible and allowed visualization of the reconstructed fiber pathways. Navigated ultrasonography controlled brain shift.

CONCLUSIONS

Integration of probabilistic fiber tracking and navigated ultrasonography into intraoperative neuronavigation facilitated anatomic orientation during glioma resection. FSL-based probabilistic fiber tracking integrated sophisticated fiber tracking algorithms, including modeling of crossing fibers. Combination with navigated ultrasonography provided a three-dimensional estimation of intraoperative brain shift and, therefore, improved the reliability of neuronavigation.

Overexpression of vascular adhesion protein-1 is associated with poor prognosis of astrocytomas

Vascular adhesion protein-1 (VAP-1) is one of the endothelial adhesion molecules that is believed to play a role in tumor progression and metastasis, supporting cancer cell extravasation. Very few studies have been performed on analyzing the contribution of VAP-1 in brain tumor. Astrocytomas are the most common type of brain tumors, which are classified by World Health Organization (WHO) into four grades according to the degree of malignancy. This study was designed to investigate VAP-1 expression level in different astrocytoma grades and its correlation with clinicopathological features as well as prognosis of astrocytoma patients. Eighty-seven patients with different grades of astrocytoma (WHO Grade I-Grade IV) were enrolled in this study. The expression of VAP-1 was assayed by immunohistochemistry. The correlation between VAP-1 expression and clinicopathological features was evaluated by Chi-square test, and overall survival was analyzed by Kaplan-Meier method. Cox regression analysis was applied to analyze the independent influence of each parameter on overall survival. The expression level of VAP-1 was significantly higher in diffuse astrocytoma than those of pilocytic astrocytoma (p < 0.0001). In the subgroup analysis, upregulated VAP-1 expression was frequently found in older age patients (≥50 years). The VAP-1 expression was found to be significantly correlated with the overall survival (p = 0.0002). There was a statistical correlation between VAP-1(high) tumors in diffuse astrocytoma and VAP-1(low) tumors in pilocytic astrocytoma (p < 0.0001). Multivariate Cox analysis indicated VAP-1 was an independent predictive marker for poorer prognosis (p = 0.0036). Therefore, VAP-1 could be a promising prognostic biomarker in astrocytoma.

Overexpression of ubiquitin-specific protease 2a (USP2a) and nuclear factor erythroid 2-related factor 2 (Nrf2) in human gliomas

BACKGROUND

Gliomas are among the most frequent adult primary brain tumors. Recent studies have shown that there are novel opportunities for developing therapeutics by targeting the differentiation and self-renewal features of glioma.

OBJECTIVE

The aim of this study was to evaluate the expression levels of USP2a an Nrf2 in patients with glioma and their association with prognosis of gliomas that was detected with immunohistochemical staining.

METHODS

In this study, 40 patient's tissue samples with primary gliomas were collected between January 2009 and December 2013. MRI of patients was done before and within 24 h after surgery. USP2a and Nrf2 expression levels were examined by immunohistochemistry. Data were analyzed using the SPSS 16.0, X(2) test, log-rank test and Kaplan-Meier method.

RESULTS

Immunohistochemistry indicated that USP2a expression was increased in glioma cells than normal brain tissues. The increased USP2a staining was markedly correlated with advanced tumor grade (P=0.02) and age (P=0.016). Our result showed that Nrf2 expression was significantly higher in glioma cells as compared to normal brain tissues. The high expression level of Nrf2 was markedly linked to age (P=0.007), and tumor grade (P=0.03). Kaplan-Meier survival and log-rank analysis indicated that patients with low expression of USP2a had longer overall survival than those with high levels (log-rank test P<0.001). Moreover, patients with high Nrf2 expression had shorter overall survival than those with low levels (log-rank test P<0.001). In the univariate analysis, the high expression of Nrf2 and USP2a (P=0.004; P=0.006), age (P=0.025), and tumor grade (P=0.001) were correlated with poor survival. Multivariate Cox proportional hazards model indicated that, high Nrf2 and USP2a staining (P=0.001; P=0.003), advanced tumor grade (P=0.01) and age (P=0.033) were independent predictor of overall survival.

CONCLUSION

In summary, the result of this study showed USP2a and Nrf2 may be as prognostic marker in patients with gliomas.

Fluoxetine, an antidepressant, suppresses glioblastoma by evoking AMPAR-mediated calcium-dependent apoptosis

The efficacy of glioblastoma chemotherapy is not satisfactory; therefore, a new medication is expected to improve outcomes. As much evidence shows that antidepressants decrease cancer incidence and improve patients' quality of life, we therefore attempted to explore the potential for fluoxetine to be used to treat GBM and its possible underlying mechanism. The expression level of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) was determined using immunohistochemical staining and PCR analysis. The mechanism of fluoxetine-induced apoptosis of gliomas was elucidated. Computer modeling and a binding assay were conducted to investigate the interaction of fluoxetine with the AMPAR. The therapeutic effect of fluoxetine was evaluated using an animal model. We found that fluoxetine directly bound to AMPAR, thus inducing transmembrane Ca²⁺ influx. The rise in the intracellular calcium concentration ([Ca²⁺]_i) causes mitochondrial Ca²⁺ overload, thereby triggering apoptosis. AMPARs are excessively expressed in glioma tissues, suggesting that fluoxetine specifically executes glioma cells. Our in vivo study revealed that fluoxetine suppressed the growth of glioblastomas in brains of Nu/Nu mice, an effect similar to that produced by temozolomide. Our preclinical studies suggest fluoxetine, a commonly used antidepressant, might be selectively toxic to gliomas and could provide a new approach for managing this disease.

Glioblastoma: Radiation treatment margins, how small is large enough?

Standard treatment for glioblastoma consists of surgical resection followed by radiation therapy with concurrent and adjuvant chemotherapy. Conventional radiation clinical treatment volumes include a 2- to 3-cm margin around magnetic resonance imaging or computed tomography enhancing abnormalities in the brain as well as a margin around the T2 or fluid-attenuated inversion recovery abnormality. However, there remains significant variability with respect to whether such extensive margins are necessary. Collectively, we as authors of this manuscript also use different margins, with A.G.W. employing European Organization for Research and Treatment of Cancer recommendations of a 2- to 3-cm margin on T1 enhancement for 60 Gy and M.P.M. using Radiation Therapy Oncology Group recommendations of 2 cm on T2 signal abnormality for the initial 46 Gy and 2.5-cm margin on T1 enhancement for a 14-Gy boost. Our experiences reflect the heterogeneity of margin definition and selection for this disease and underscore an important area of further research to minimize this variability. In this article, we review studies exploring recurrence patterns and outcomes in patients treated using both conventional and more limited margins. We conclude that treating to "smaller" margins does not alter recurrence patterns nor does it result in inferior survival, but whether this is because of the inherently limited benefit of radiation therapy in the first place, or whether it is truly because microscopic tumor control at larger distances is not an issue, remains unestablished.

Expression and prognostic value of the aldehyde dehydrogenase 1 (ALDH1) and N-myc downstream regulated gene 2 (NDRG2) as potential markers in human astrocytomas

In this study, immunohistochemical analysis was used to evaluate the expression of ALDH1 and NDRG2 in astrocytoma tissue samples and normal brain tissues. ALDH1 protein staining displayed that AlDH1 expression was not detectable in eight astrocytoma tissues (8/36) and in all of normal brain tissues. There was a significant difference between ALDH1 expression and WHO grades (P = 0.03). Furthermore, no correlation was determined between expression levels of ALDH1 and other clinicopathological characteristics including age, sex, and tumor size. Immunohistochemistry showed that a high level of NDRG2 protein expression was markedly detected in normal brain tissues and expression of NDRG2 protein was significantly decreased in astrocytoma tissues. There was a significant association between pathological grading and NDRG2 expression level (P < 0.001, Table 1), but no correlation was determined between expression levels of NDRG2 and other clinicopathological characteristics including age, sex, and tumor size. We also obtained detailed follow-up data and evaluated the association of ALDH1/NDRG2 expressions with overall survival. Kaplan-Meier survival and log-rank analysis indicated that the patients with high proportion of ALDH1-positive cells and low proportion of NDRG2-positive had shorter overall survival (P < 0.001; P = 0.001). Univariate analysis indicated that the high proportion of ALDH1-positive cells (P < 0.001), the low proportion of NDRG2-positive cells (P = 0.009), and the advanced grade (P < 0.005) were markedly linked to the prognosis in patients. Furthermore, in the multivariate analysis, ALDH1 cells' expression (P = 0.012), low proportion of NDRG2-positive cells (P = 0.025), and advanced grade (P < 0.03) were linked to poor overall survival. Our results suggest that NDRG2 expression is related to decreased survival rates and NDRG2 may be a potential marker in the astrocytoma prognosis. NDRG2 may be a potential marker in the astrocytoma prognosis. ALDH1 expression was related to advanced pathological grade and survival rate in astrocytoma patients.

A data-motivated density-dependent diffusion model of in vitro glioblastoma growth

Glioblastoma multiforme is an aggressive brain cancer that is extremely fatal. It is characterized by both proliferation and large amounts of migration, which contributes to the difficulty of treatment. Previous models of this type of cancer growth often include two separate equations to model proliferation or migration. We propose a single equation which uses density-dependent diffusion to capture the behavior of both proliferation and migration. We analyze the model to determine the existence of traveling wave solutions. To prove the viability of the density-dependent diffusion function chosen, we compare our model with well-known in vitro experimental data.

Autoantibody Profiling of Glioma Serum Samples to Identify Biomarkers Using Human Proteome Arrays

The heterogeneity and poor prognosis associated with gliomas, makes biomarker identification imperative. Here, we report autoantibody signatures across various grades of glioma serum samples and sub-categories of glioblastoma multiforme using Human Proteome chips containing ~17000 full-length human proteins. The deduced sets of classifier proteins helped to distinguish Grade II, III and IV samples from the healthy subjects with 88, 89 and 94% sensitivity and 87, 100 and 73% specificity, respectively. Proteins namely, SNX1, EYA1, PQBP1 and IGHG1 showed dysregulation across various grades. Sub-classes of GBM, based on its proximity to the sub-ventricular zone, have been reported to have different prognostic outcomes. To this end, we identified dysregulation of NEDD9, a protein involved in cell migration, with probable prognostic potential. Another subcategory of patients where the IDH1 gene is mutated, are known to have better prognosis as compared to patients carrying the wild type gene. On a comparison of these two cohorts, we found STUB1 and YWHAH proteins dysregulated in Grade II glioma patients. In addition to common pathways associated with tumourigenesis, we found enrichment of immunoregulatory and cytoskeletal remodelling pathways, emphasizing the need to explore biochemical alterations arising due to autoimmune responses in glioma.

Retinoic acid‑incorporated glycol chitosan nanoparticles inhibit the expression of Ezh2 in U118 and U138 human glioma cells

At present, one of the most life threatening types of adult brain tumor is glioblastoma multiforme (GBM). The molecular mechanism underlying the progression of GBM remains to be fully elucidated. The modern method of clinical treatment has only improved the average survival rates of a newly diagnosed patients with GBM by ~15 months. Therefore, the discovery of novel molecules, which are involved in glioma inhibition is required. In the present study, U118 and U138 human glioma cells were transfected with all-trans retinoic acid (RA)-incorporated glycol chitosan (GC) nanoparticles. An MTT assay was used for the analysis of cell proliferation and flow cytometric analysis and ssDNA detection assays were performed for the determination of induction of cell apoptosis. Cell cycle distribution was analyzed by flow cytometry. Exposure of the U118 and U138 human glioma cells to the RA-incorporated GC nanoparticles for 24 h resulted in a concentration-dependent inhibition of cell proliferation. Among the range of experimental RA concentrations, the minimum effective treatment concentration was 10 µM, with a half maximal inhibitory concentration of 25 µM. The results also demonstrated that RA transfection resulted in the inhibition of cell proliferation, inhibition of the expression of Ezh2, and apoptosis through the mitochondrial signaling pathway by a decrease in membrane potential, the release of cytochrome c, and cell cycle arrest in the G₀/G₁ phase.

Effect of temozolomide on livin and caspase-3 in U251 glioma stem cells

The aim of the present study was to analyze the effect of temozolomide (TMZ) on the antiapoptotic gene livin and the associated gene caspase-3. Cancer stem cells were isolated from U251 glioblastoma cells using immunomagnetic beads. The glioma cells and glioma stem cells were transfected with livin or small hairpin RNA (shRNA) against livin using lentiviral vectors. Quantitative PCR, flow cytometry and a Cell Counting kit-8 assay were used to detect the expression of livin and caspase-3, analyze the cell cycle and investigate cell proliferation, respectively, following treatment with various concentrations of TMZ (0, 25, 50, 100, 200 and 400 μmol/l) for different periods of time (24, 48 and 72 h). The expression levels of livin and caspase-3 in the U251 stem cells were significantly higher than those in the U251 cells (P<0.01). At the same intervention time, the expression levels of livin decreased and those of caspase-3 increased as the concentration of TMZ increased (P<0.05). The expression levels of livin and caspase-3 in the U251 cells were lower than those in the U251 stem cells with the same intervention time and concentration of TMZ (P<0.05). The cell cycle was arrested in the G2/M phase in the U251 cells following TMZ intervention; the proportion of cells in the G2/M phase increased as the concentration of TMZ increased (P<0.05). The U251 stem cells were arrested in the S phase following treatment with TMZ; the proportion of cells in the S phase increased as the concentration of TMZ increased (P<0.05). In conclusion, the expression levels of livin and caspase-3 were effectively inhibited and increased, respectively, in all cell models following treatment with TMZ. TMZ is able to arrest the cell cycle and enhance cell apoptosis. U251 stem cells are less vulnerable than U251 cells to TMZ.

Responsiveness of stem-like human glioma cells to all-trans retinoic acid and requirement of retinoic acid receptor isotypes α, β and γ

Retinoic acid (RA) is required for development and homeostasis of the normal mammalian brain and may play a role in the initiation and progression of malignant brain tumors, such as the glioblastoma multiforme (GBM) and the gliosarcoma (Gsarc). The subpopulation of stem-like glioma cells (SLGCs) was shown to resist standard glioma radio-/chemotherapy and to propagate tumor regrowth. We used phenotypically distinct, self-renewing SLGC lines from six human GBMs, two Gsarcs, and two subcloned SLGC derivatives in order to investigate their responsiveness to all-trans retinoic acid (atRA) and to identify the RA-receptor (RAR) isotypes involved. In general, atRA exerted a pro-proliferative and pro-survival effect on SLGCs, though the efficacy was distinct. By means of RAR isotype-selective retinoids we disclosed that these effects were mediated by RARα and RARγ, except for one SLGC line, in which the pro-proliferative signal was induced by the RARβ-selective retinoid. Only one GBM-derived cell line (T1338) and a subpopulation of another (T1389) displayed neural differentiation in response to atRA. Differentiation of T1338 was induced by RARα and RARγ isotype-selective retinoids, associated with down-regulation of Sox2, and the failure to induce orthotopic tumors in the brains of SCID mice. The differential responsiveness of the SLGC lines appeared unrelated to the expression of RARβ, as (i) atRA augmented RAR isotype mRNA expression and particularly rarβ mRNA in all SLGC lines, (ii) rarβ promoter hypomethylation in the SLGC lines was not related to differentiation and (iii) the induction of T1338 differentiation was by RARα- and RARγ-selective ligands.

Circulating anti-filamin C autoantibody as a potential serum biomarker for low-grade gliomas

Background

Glioma is the most common primary malignant central nervous system tumor in adult, and is usually not curable due to its invasive nature. Establishment of serum biomarkers for glioma would be beneficial both for early diagnosis and adequate therapeutic intervention. Filamins are an actin cross-linker and filamin C (FLNC), normally restricted in muscle tissues, offers many signaling molecules an essential communication fields. Recently, filamins have been considered important for tumorigenesis in cancers.

Methods

We searched for novel glioma-associated antigens by serological identification of antigens utilizing recombinant cDNA expression cloning (SEREX), and found FLNC as a candidate protein. Tissue expressions of FLNC (both in normal and tumor tissues) were examined by immunohistochemistry and quantitative RT-PCR analyses. Serum anti-FLNC autoantibody level was measured by ELISA in normal volunteers and in the patients with various grade gliomas.

Results

FLNC was expressed in glioma tissues and its level got higher as tumor grade advanced. Anti-FLNC autoantibody was also detected in the serum of glioma patients, but its levels were inversely correlated with the tissue expression. Serum anti-FLNC autoantibody level was significantly higher in low-grade glioma patients than in high-grade glioma patients or in normal volunteers, which was confirmed in an independent validation set of patients’ sera. The autoantibody levels in the patients with meningioma or cerebral infarction were at the same level of normal volunteers, and they were significantly lower than that of low-grade gliomas. Total IgG and anti-glutatione S-transferase (GST) antibody level were not altered among the patient groups, which suggest that the autoantibody response was specific for FLNC.

Conclusions

The present results suggest that serum anti-FLNC autoantibody can be a potential serum biomarker for early diagnosis of low-grade gliomas while it needs a large-scale clinical study.

Upregulation of the Kank1 gene-induced brain glioma apoptosis and blockade of the cell cycle in G0/G1 phase

The Kank1 gene is one of the important members of the Kank gene family. As an important adaptor protein, Kank1 plays a significant role in the genesis and development of many malignant tumors. It was recently discovered that the Kank1 gene is a new cancer suppressor, and its expression is significantly downregulated or it is not expressed in kidney cancer, bladder cancer, prostate cancer, lung cancer and breast cancer. However, no report on the role of Kank1 in the genesis of brain glioma is available to date. In this study, we found significantly lower expression of the Kank1 gene in human brain glioma cells compared to the other cells evaluated. We used RNA interference techniques to silence Kank1 gene expression and found acceleration of tumor cell proliferation. However, when the Kank1 gene was upregulated, cell apoptosis occurred and the cell cycle was blocked in the G0/G1 phase. Also, we found that upregulating the Kank1 gene may result in the change of mitochondrial membrane potential, and the regulation of Bax and Bcl-2 may promote the mitochondria to release cytochrome C so as to activate Caspase-9 and -3. Thus, the human brain glioma apoptosis induced by upregulation of the Kank1 gene is closely relevant to the mitochondrial pathway.

The Methanol Extract of Angelica sinensis Induces Cell Apoptosis and Suppresses Tumor Growth in Human Malignant Brain Tumors

Glioblastoma multiforme (GBM) is a highly vascularized and invasive neoplasm. The methanol extract of Angelica sinensis (AS-M) is commonly used in traditional Chinese medicine to treat several diseases, such as gastric mucosal damage, hepatic injury, menopausal symptoms, and chronic glomerulonephritis. AS-M also displays potency in suppressing the growth of malignant brain tumor cells. The growth suppression of malignant brain tumor cells by AS-M results from cell cycle arrest and apoptosis. AS-M upregulates expression of cyclin kinase inhibitors, including p16, to decrease the phosphorylation of Rb proteins, resulting in arrest at the G₀-G₁ phase. The expression of the p53 protein is increased by AS-M and correlates with activation of apoptosis-associated proteins. Therefore, the apoptosis of cancer cells induced by AS-M may be triggered through the p53 pathway. In in vivo studies, AS-M not only suppresses the growth of human malignant brain tumors but also significantly prolongs patient survival. In addition, AS-M has potent anticancer effects involving cell cycle arrest, apoptosis, and antiangiogenesis. The in vitro and in vivo anticancer effects of AS-M indicate that this extract warrants further investigation and potential development as a new antibrain tumor agent, providing new hope for the chemotherapy of malignant brain cancer.

Characterizing the role of PCDH9 in the regulation of glioma cell apoptosis and invasion

PCDH9, a member of the protocadherin superfamily, is frequently lost in many different cancer types. This study aimed to detect PCDH9 expression in glioma tissues. This study also assessed the effects of PCDH9 expression in two different glioma cell lines. This was accomplished by manipulating PCDH9 expression in these glioma cell lines. The data showed that the expression of PCDH9 mRNA and protein was significantly decreased in gliomas compared to normal brain tissues. Lentivirus carrying PCDH9 cDNA restored PCDH9 expression in the U87 and U251 glioma cell lines. PCDH9 restoration in these cell lines reduced tumor cell viability, induced apoptosis, and caused G0/G1 cell cycle arrest. PCDH9 expression also suppressed the colony formation ability and invasion capacity of U87 and U251 cells. Molecularly, the restoration of PCDH9 expression upregulated Bax protein expression, but downregulated Bcl-2 and cyclin D1 expression. These data from the current study suggest that the loss of PCDH9 expression could contribute to glioma development and/or progression. Further studies will evaluate PCDH9 expression as a biomarker for the early detection of gliomas and as a prognostic indicator for this cancer type.