Epidemiology of brain tumors

Association between nonsteroidal anti-inflammatory drugs use and risk of central nervous system tumors: a dose-response meta analysis

Although studies have examined the association between nonsteroidal anti-inflammatory drugs (NSAIDs) use and central nervous system (CNS) tumors risk, the results are inconclusive. Here, we conducted a dose-response meta-analysis in order to investigate the correlation between NSAIDs use and CNS tumors risk. Up to July 2017, 12 studies were included in current meta-analysis. NSAIDs use was significantly associated with a lower risk of CNS tumors. Furthermore, non-aspirin NSAIDs or aspirin use are significantly associated with a lower risk of CNS tumors. Additionally, NSAIDs use was associated with significantly a lower risk of glioma, glioblastoma but not meningioma. Subgroup analysis showed consistent findings. Furthermore, a significant dose-response relationship was observed between NSAIDs use and CNS tumors risk. Increasing cumulative 100 defined daily dose of NSAIDs use was associated with a 5% decrement of CNS tumors risk, increasing NSAIDs or non-aspirin NSAIDs or aspirin use (per 3 prescriptions increment) was associated with a 7%, 7%, 10% decrement of CNS tumors risk, increasing per 2 year of duration of NSAIDs or non-aspirin NSAIDs or aspirin use was associated with a 6%, 8%, 6% decrement of CNS tumors risk. Considering these promising results, NSAIDs use might provide helpful for reducing CNS tumors risk. Large sample size and different ethnic population are warranted to validate this association.

Targeting cellular pathways in glioblastoma multiforme

Glioblastoma multiforme (GBM) is a debilitating disease that is associated with poor prognosis, short median patient survival and a very limited response to therapies. GBM has a very complex pathogenesis that involves mutations and alterations of several key cellular pathways that are involved in cell proliferation, survival, migration and angiogenesis. Therefore, efforts that are directed toward better understanding of GBM pathogenesis are essential to the development of efficient therapies that provide hope and extent patient survival. In this review, we outline the alterations commonly associated with GBM pathogenesis and summarize therapeutic strategies that are aimed at targeting aberrant cellular pathways in GBM.

The regulator of calcineurin 1 (RCAN1) inhibits nuclear factor kappaB signaling pathway and suppresses human malignant glioma cells growth

Nuclear factor-kappaB (NF-κB) has a vital role in cell survival and inhibition of NF-κB had proven to be an efficient therapeutic pathway for various cancers though little is known about the underlying mechanism. Previously we identified regulator of calcineurin 1 (RCAN1) as an endogenous inhibitor of NF-κB signaling pathway in lymphoma. In the present study, we have solid data to show that RCAN1 can inhibit the nuclear translocation of NF-κB protein then affect the activity of NF-κB signaling pathway in glioma cells. Overexpression of RCAN1 markedly reduced glioma cells viability. We further found that the suppressing glioma cell growth was closely related to the pro-apoptosis effect, not by inhibiting proliferation by the arrest of cell cycle. Our study implicated a novel therapeutic approach for glioma by RCAN1 through inhibition of NF-κB signaling.

Genomic copy number gains of ErbB family members predict poor clinical outcomes in glioma patients

The aim of this study was to investigate copy number of ErbB family members (including EGFR, HER2, HER3 and HER4) in a cohort of gliomas and benign meningiomas (control subjects), and explore the associations of their copy number with clinicopathological characteristics and clinical outcomes of glioma patients. Using real-time quantitative PCR assay, we demonstrated that copy number of EGFR, HER2, HER3 and HER4 in glioma patients was significantly increased compared to control subjects. Moreover, our data also showed that the risk of cancer-related death was positively associated with copy number gain (CNG) of EGFR, HER3 and HER4, but not HER2. CNG of EGFR and HER2 was positively related to radiotherapy, while CNG of HER3 and HER4 was negatively related to chemotherapy. Importantly, EGFR CNG significantly shortened median survival times of glioma patients regardless of gender, tumor grade and therapeutic regimens. Stratified analysis showed that CNG of HER2-4 almost did not influence the survival of male patients, patients with high-grade tumors and patients receiving chemotherapy, but dramatically shortened median survival times of female patients, those with low-grade tumors and those receiving radiotherapy. Collectively, our data not only demonstrate that the members of ErbB family are frequently amplified in gliomas, but also suggest that these common genetic events may be prognostic factors for poor clinical outcomes in glioma patients.

Co-delivery of tumor-derived exosomes with alpha-galactosylceramide on dendritic cell-based immunotherapy for glioblastoma

Dendritic cell (DC) vaccine-based immunotherapy for glioblastoma multiforme (GBM) has shown apparent benefit in animal experiments and early-phase clinical trials, but the survival benefit is variable. In this work, we analyzed the mechanism of the potent antitumor immune response induced in vivo by tumor-associated antigen (TAA)-specific DCs with an invariant natural killer T (iNKT) cell adjuvant in orthotopic glioblastoma-bearing rats vaccinated with tumor-derived exosomes and α-galactosylceramide (α-GalCer) -pulsed DCs. Compared with traditional tumor lysate, exosomes were utilized as a more potent antigen to load DCs. iNKT cells, as an effective cellular adjuvant activated by α-GalCer, strengthened TAA presentation through their interaction with DCs. Co-delivery of tumor-derived exosomes with α-GalCer on a DC-based vaccine showed powerful effects in glioblastoma immunotherapy. This vaccine induced strong activation and proliferation of tumor-specific cytotoxic T lymphocytes, synergistically breaking the immune tolerance and improving the immunosuppressive environment.

Occupational solvent exposure and risk of glioma in the INTEROCC study

Background:

The aetiology of glioma remains largely unknown. Occupational solvent exposure has been suggested as a putative cause of glioma, but past studies have been inconsistent. We examined the association between a range of solvents and glioma risk within the INTEROCC project, a study of brain tumours and occupational exposures based on data from seven national case–control studies conducted in the framework of the INTERPHONE study. We also investigated associations according to tumour grade.

Methods:

Data from the seven countries were standardised and then combined into one aggregate data set. Pooled odds ratios (ORs) were estimated for adjusted models that included sex, age, country–region of residence and level of educational attainment. Exposures to any solvent or 11 specific solvents or subgroups were assessed using a modified version of the FINJEM job exposure matrix (JEM) specifically developed for the study, called INTEROCC-JEM.

Results:

Analysis included 2000 glioma cases and 5565 controls. For glioma and ever/never exposure to any solvent, the OR was 0.91 (95% confidence interval: 0.74–1.11). All ORs were <1.0 for specific solvents/subgroups. There were no increases in risk according to high or low grade of tumour.

Conclusions:

The results of this study show no consistent associations for any solvent exposures overall or by grade of tumour.

Quantitative analysis of permeability for glioma grading using dynamic contrast-enhanced magnetic resonance imaging

The objective of the present study was to quantitatively analyze the permeability of tumor entity and peritumor edema in glioma grading, using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). In the present retrospective study, 80 patients underwent T1-weighted DCE-MRI examination at 3.0 T and the pathological results (including astrocytoma and oligodendroglioma) were obtained between January 2012 and June 2015. All cases were surgically validated as grade I–IV gliomas. The original DCE-MRI data were analyzed using dual compartment modified Tofts model. The forward volume transfer constant (K^trans), backflux rate (k_ep) and fractional volume (v_e) were calculated with the region of interest selected on the highest permeability area of the tumor entity and peritumor edema. Analysis of variance with the Bonferroni correction was used to compare the values of K^trans, k_ep, and v_e of the tumor entity and peritumor edema in different glioma grades. The results of the present study revealed that the K^trans, k_ep, and v_e values in each stage were associated with the pathological grading (r=0.951, 0.804 and 0.766, respectively). There were significant differences identified between different tumor grades in K^trans, k_ep, with the exception being between grades II and III in k_ep. In addition, there was a significant difference revealed between grade I/II and grade III/IV in v_e. Receiver operator characteristics curve analysis was used to evaluate the diagnosis accuracies of permeability parameters. K^trans was demonstrated to exhibit the highest sensitivity and specificity for evaluating the tumor grade. With the threshold values of 0.160, 0.420 and 0.935 in K^trans on tumor, glioma grades I vs. II, II vs III and III vs. IV may be differentiated with sensitivities of 0.900, 0.950 and 0.950, and specificities of 0.950, 0.950 and 0.850, respectively. Furthermore, associations were observed between the K^trans, k_ep and v_e values of peritumor edema and the pathological grading in glioma (K^trans r=0.438, P<0.001; K_ep r=0.385, P<0.001; V_e r=0.397, P<0.001, respectively). K^trans values in peritumoral edema revealed significant differences between low-grade and high-grade glioma. The sensitivity and specificity for K^trans of peritumor edema were 0.975 and 0.950, with a threshold value of 0.007. Therefore, the DCE-MRI parameters of K^trans of tumor entity and peritumor edema in gliomas may be used to accurately differentiate glioma grades.

Intraoperative imaging technology to maximise extent of resection for glioma

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

To establish the overall effectiveness and safety of intraoperative imaging in resection of glial tumours.

Effect of CCL2 siRNA on proliferation and apoptosis in the U251 human glioma cell line

Glioma is one of the most common types of tumor of the central nervous system. Increased expression of C‑C motif chemokine 2 (CCL2) has previously been observed in various types of cancer. The effect of CCL2 small interfering (si)RNA on the proliferation, angiogenesis and apoptosis of the glioma cell line U251 was investigated in the present study. Data on CCL2 expression in glioma and normal tissues were obtained from The Cancer Genome Atlas. A total of 30 patients with glioma were enrolled in the present study. Cell proliferation was measured using a Cell Counting kit‑8 assay, while cellular apoptosis and cell cycle distribution were examined using flow cytometric analysis. The reverse transcription‑quantitative polymerase chain reaction and western blot analysis were used to measure the expression levels of biological pathway‑associated proteins caspase‑3, caspase‑7, tumor necrosis factor receptor superfamily member 10C (TNFRSF10C), growth regulated α protein (CXCL1), C‑X‑C motif chemokine 2 (CXCL2), C‑X‑C chemokine receptor type 2 (CXCR2), vascular endothelial growth factor (VEGF)A, VEGFB and VEGF. In addition, the mechanism of cellular apoptosis was analyzed by examining the phosphorylation of extracellular signal‑related kinase (ERK)1/2 and p38 mitogen‑activated protein kinase (p38) in cells treated with the C‑C chemokine receptor type 2 inhibitor RS‑102895. CCL2 was observed to be expressed in the glioma cell line U251 and was inhibited by CCL2 siRNA. Cells transfected with CCL2 siRNA exhibited inhibited cell proliferation, cell cycle arrest and increased cellular apoptosis. The expression levels of the apoptosis‑associated proteins caspase‑3, caspase‑7 and TNFRSF10C were observed to be downregulated, in addition to those of the angiogenesis‑associated proteins CXCL1, CXCL2, CXCR2, VEGFA, VEGFB and VEGF. The decrease in the rate of phosphorylation of ERK1/2 and p38 demonstrated the involvement of the mitogen‑activated protein kinase/ERK pathway in apoptosis. In conclusion, CCL2 siRNA exhibited effective inhibition of cell proliferation and angiogenesis in the glioma cell line U251, which may provide a theoretical basis for the use of CCL2 in in vivo research and clinical treatment as a novel anticancer agent.

Remission spectrometry for blood vessel detection during stereotactic biopsy of brain tumors

Stereotactic biopsy is used to enable diagnostic confirmation of brain tumors and treatment planning. Despite being a well-established technique, it is related to significant morbidity and mortality rates mostly caused by hemorrhages due to blood vessel ruptures. This paper presents a method of vessel detection during stereotactic biopsy that can be easily implemented by integrating two side-view fibers into a conventional side-cutting biopsy needle. Tissue within the needle window is illuminated through the first fiber; the second fiber detects the remitted light. By taking the ratio of the intensities at two wavelengths with strongly differing hemoglobin absorption, blood vessels can be recognized immediately before biopsy sampling. Via ray tracing simulations and phantom experiments, the dependency of the remission ratio R = I₅₇₈ /I₆₅₀ on various parameters (blood oxygenation, fiber-to-vessel and inter-fiber distance, vessel diameter and orientation) was investigated for a bare-fiber probe. Up to 800-1200 µm away from the probe, a vessel can be recognized by a considerable reduction of the remission ratio from the background level. The technique was also successfully tested with a real biopsy needle probe on both optical phantoms and ex-vivo porcine brain tissue, thus showing potential to improve the safety of stereotactic biopsy. Dual-wavelength remission measurement for the detection of blood vessels during stereotactic biopsy.

A prospective study of serum metabolites and glioma risk

Malignant glioma is one of the most lethal adult cancers, yet its etiology remains largely unknown. We conducted a prospective serum metabolomic analysis of glioma based on 64 cases and 64 matched controls selected from Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study. Median time from collection of baseline fasting serum to diagnosis was nine years (inter-decile range 3-20 years). LC/MS-MS identified 730 known metabolites, and conditional logistic regression models estimated odds ratios for one-standard deviation differences in log-metabolite signals. Forty-three metabolites were associated with glioma at P<0.05. 2-Oxoarginine, cysteine, alpha-ketoglutarate, chenodeoxycholate and argininate yielded the strongest metabolite signals and were inversely related to overall glioma risk (0.0065≤P<0.0083). Also, seven xanthine metabolites related to caffeine metabolism were higher in cases than in controls (0.017≤P<0.042). Findings were mostly similar in high-grade glioma cases, although prominent inversely associated metabolites included the secondary bile acids glycocholenate sulfate and 3β-hydroxy-5-cholenoic acid, xenobiotic methyl 4-hydroxybenzoate sulfate, sex steroid 5alpha-pregnan-3beta, 20beta-diol-monosulfate, and cofactor/vitamin oxalate (0.0091≤P<0.021). A serum metabolomic profile of glioma identified years in advance of clinical diagnoses is characterized by altered signals in arginine/proline, antioxidant, and coffee-related metabolites. The observed pattern provides new potential leads regarding the molecular basis relevant to etiologic or sub-clinical biomarkers for glioma.

Overexpression of mitochondrial serine hydroxyl-methyltransferase 2 is associated with poor prognosis and promotes cell proliferation and invasion in gliomas

Mitochondrial serine hydroxyl-methyltransferase 2 (SHMT2), participating in the synthesis of mitochondrial thymidine monophosphate, has been reported to drive glioma cell survival in ischemia. However, its clinical relevance in gliomas remains unclear. In the current study, immunohistochemistry was performed to examine subcellular localization and expression levels of SHMT2 protein in glioma and non-neoplastic brain tissue specimens. Then, the associations of SHMT2 expression with various clinicopathological features and patients’ prognosis were statistically evaluated. The roles of SHMT2 in the proliferation and invasion of glioma cells after siRNA-SHMT2 vector transfection were also detected by cell counting kit-8 and transwell assays, respectively. Results showed that SHMT2 immunostaining was predominantly localized in the cellular cytoplasm of tumor cells in glioma tissues but weakly in non-neoplastic brain tissues. Statistically, SHMT2 protein expression was significantly higher in glioma tissues than in non-neoplastic brain tissues (P<0.001). In addition, SHMT2 overexpression more frequently occurred in glioma patients with an advanced grade of malignancy (P<0.001) and poor prognosis (P=0.001). Notably, multivariate analysis based on a Cox regression model identified SHMT2 expression as an independent prognostic factor for glioma patients (P=0.01). Functionally, SHMT2 knockdown efficiently suppressed the proliferation (P=0.02) and invasion (P<0.001) of glioma cells in vitro. In conclusion, our findings suggest that SHMT2 may function as an oncogene in glioma development and progression. Clinically, SHMT2 may serve as a prognostic factor and as a potential therapeutic target for human gliomas.

Immunotherapy targeting immune check-point(s) in brain metastases

Immunotherapy with monoclonal antibodies (mAb) directed to different immune check-point(s) is showing a significant clinical impact in a growing number of human tumors of different histotype, both in terms of disease response and long-term survival patients. In this rapidly changing scenario, treatment of brain metastases remains an high unmeet medical need, and the efficacy of immunotherapy in these highly dismal clinical setting remains to be largely demonstrated. Nevertheless, up-coming observations are beginning to suggest a clinical potential of cancer immunotherapy also in brain metastases, regardless the underlying tumor histotype. These observations remain to be validated in larger clinical trials eventually designed also to address the efficacy of therapeutic mAb to immune check-point(s) within multimodality therapies for brain metastases. Noteworthy, the initial proofs of efficacy on immunotherapy in central nervous system metastases are already fostering clinical trials investigating its therapeutic potential also in primary brain tumors. We here review ongoing immunotherapeutic approaches to brain metastases and primary brain tumors, and the foreseeable strategies to overcome their main biologic hurdles and clinical challenges.

miR-543 functions as a tumor suppressor in glioma in vitro and in vivo

Gliomas are the most common primary central nervous system tumors and account for approximately 80% of malignant brain tumors. MicroRNAs (miRNAs) are a class of small non-coding, regulatory RNA molecules that mediate the expression levels of specific proteins. As a member of the miRNA family, miR-543 plays a tumor suppressive or an oncogenic role in different types of tumors. However, the expression and role of miR-543 in glioma remain unknown. In the present study, the expression level of miR-543 in glioma cell lines and tissues was investigated. A series of in vitro and in vivo experiments was then performed to elucidate the function of miR-543 in glioma. Moreover, proteomic profiling was applied in this study to determine the landscape of differentially expressed proteins associated with miR-543-mediated carcinogenesis in glioma. We found that the expression level of miR-543 was greatly downregulated in glioma cell lines and tissues. Furthermore, the expression level of miR-543 was negatively associated with high-grade glioma. Functional studies demonstrated that miR-543 in glioma cells induced apoptosis and inhibited growth, the cell cycle, migration and invasion. In addition, the in vivo study showed that miR-543 suppressed tumorigenicity of glioma cells. In the present study, a label-free quantitative proteomic approach was performed and 339 proteins were identified as dysregulated after miR-543 was overexpressed. Among these dysregulated proteins, 165 were upregulated and 174 were downregulated. Moreover, multiple pathways were significantly enriched and were probably involved in miR-543-mediated tumorigenesis, including RNA degradation and the inositol phosphate metabolism pathway. In conclusion, miR-543 may function as a tumor suppressor in glioma and may serve as a future therapeutic target in therapy for patients with glioma.

Loss of SH3GL2 promotes the migration and invasion behaviours of glioblastoma cells through activating the STAT3/MMP2 signalling

SH3GL2 (Src homology 3 (SH3) domain GRB2‐like 2) is mainly expressed in the central nervous system and regarded as a tumour suppressor in human glioma. However, the molecular mechanism of the SH3GL2 protein involved in malignant behaviours of human glioma has not been elucidated. In this study, we tried to investigate the role of SH3GL2 in glioma cell migration and invasion and explore its underlined molecular mechanism. Firstly, we discovered that the protein level of SH3GL2 was widely decreased in the human glioma patients, especially in high‐grade glioma tissues. Then, we determined the role of SH3GL2 in migration and invasion of glioma cells upon SH3GL2 knocking down and overexpressing. It was showed that knocking down of SH3GL2 promoted the migration and invasion of glioma cells, whereas overexpression of SH3GL2 inhibited them. Further study on molecular mechanism disclosed that silencing of SH3GL2 obviously activated the STAT3 (signal transducer and activator of transcription 3) signalling thereby promoting the expression and secretion of MMP2. On the contrary, overexpression of SH3GL2 had opposite effect. Taken together, the above results suggest that SH3GL2 suppresses migration and invasion behaviours of glioma cells through negatively regulating STAT3/MMP2 signalling and that loss of SH3GL2 may intensify the STAT3/MMP2 signalling thereby contributing to the migration and invasion of glioma cells.

Case-control study on occupational exposure to extremely low-frequency electromagnetic fields and glioma risk

BACKGROUND

Exposure to extremely low-frequency electromagnetic fields (ELF-EMF) was in 2002 classified as a possible human carcinogen, Group 2B, by the International Agency for Research on Cancer at WHO.

METHODS

Life time occupations were assessed in case-control studies during 1997-2003 and 2007-2009. An ELF-EMF Job-Exposure Matrix was used for associating occupations with ELF exposure (μT). Cumulative exposure (μT-years), average exposure (μT), and maximum exposed job (μT) were calculated.

RESULTS

Cumulative exposure gave for astrocytoma grade IV (glioblastoma multiforme) in the time window 1-14 years odds ratio (OR) = 1.9, 95% confidence interval (CI) = 1.4-2.6, p linear trend <0.001, and in the time window 15+ years OR = 0.9, 95%CI = 0.6-1.3, p linear trend = 0.44 in the highest exposure categories 2.75+ and 6.59+ μT years, respectively.

CONCLUSION

An increased risk in late stage (promotion/progression) of astrocytoma grade IV for occupational ELF-EMF exposure was found.

Reappraisal of XRCC1 Arg194Trp polymorphism and glioma risk: a cumulative meta-analysis

The association between XRCC1 Arg194Trp polymorphism and glioma risk were inconsistent from published meta-analyses and epidemiological studies. Hence, we performed this updated and cumulative meta-analysis to reappraisal this relationship. PubMed, Embase, CBM (Chinese Biomedical Database), and CNKI (China National Knowledge Internet) databases were comprehensively searched up to August 13, 2016 (updated on December 22, 2016). After study selection and data extraction from eligible studies, the association was evaluated by odds ratios (ORs) and its 95% confidence intervals (95%CIs) using Comprehensive Meta-Analysis software. Finally 16 case-control studies involving 7011 patients and 9519 healthy controls were yielded. The results indicated that XRCC1 Arg194Trp polymorphism was significantly correlated with the increased risk of glioma [Trp vs. Arg: OR = 1.18(1.05-1.34); TrpTrp vs. ArgArg: OR = 1.66(1.31-2.12); ArgTrp vs. ArgArg: OR = 1.34(1.02-1.77); TrpTrp vs. ArgArg+ArgTrp: OR = 1.47(1.26-1.72); TrpTrp+ArgTrp vs. ArgArg: OR = 1.17(1.01-1.35)]. Cumulative analysis showed the results changed from non-significant to significant when new studies accumulated, and sensitivity analysis indicated the results were stable. Subgroup analysis showed the significant association existed in Asians but not in Caucasians. Current evidence indicated that XRCC1 Arg194Trp polymorphism was associated with increased risk for glioma, especially in Asians; however, relevant studies involving other ethnic groups are required to validate our findings in further.

Survivin a radiogenetic promoter for glioblastoma viral gene therapy independently from CArG motifs

Background

Radiogenetic therapy is a novel approach in the treatment of cancer, which employs genetic modification to alter the sensitivity of tumor cells to the effect of applied radiation.

Aim

To select a potent radiation inducible promoter in the context of brain tumors and to investigate if CArG radio responsive motifs or other elements in the promoter nucleotide sequences can correlate to its response to radiation.

Methods

To select initial candidates for promoter inducible elements, the levels of mRNA expression of six different promoters were assessed using Quantitative RTPCR in D54 MG cells before and after radiation exposure. Recombinant Ad/reporter genes driven by five different promoters; CMV, VEGF, FLT-1, DR5 and survivin were constructed. Glioma cell lines were infected with different multiplicity of infection of the (promoter) Ad or CMV Ad. Cells were then exposed to a range of radiation (0–12 Gy) at single fraction. Fluorescent microscopy, Luc assay and X-gal staining was used to detect the level of expression of related genes. Different glioma cell lines and normal astrocytes were infected with Ad survivin and exposed to radiation. The promoters were analyzed for presence of CArG radio-responsive motifs and CCAAT box consensus using NCBI blast bioinformatics software.

Results

Radiotherapy increases the expression of gene expression by 1.25–2.5 fold in different promoters other than survivin after 2 h of radiation. RNA analysis was done and has shown an increase in copy number of tenfold for survivin. Most importantly cells treated with RT and Ad Luc driven by survivin promoter showed a fivefold increase in expression after 2 Gy of radiation in comparison to non-irradiated cells. Presence or absence of CArG motifs did not correlate with promoter response to radiation. Survivin with the best response to radiation had the lowest number of CCAAT box.

Conclusion

Survivin is a selective potent radiation inducible promoter for glioblastoma viral gene therapy and this response to radiation could be independent of CArG motifs.

Cancers of the brain and CNS: global patterns and trends in incidence

Background

Cancers of the brain and CNS constitute a group of rare and heterogeneous tumors. Increasing incidence in Western populations has been linked to improvements in diagnostic technology, although interpretation is hampered by changes in diagnosis and reporting. The present study examines geographic and temporal variations in incidence rates of brain and CNS cancers worldwide.

Methods

Data from successive volumes of Cancer Incidence in Five Continents were used, including 96 registries in 39 countries. We used Joinpoint regression to estimate the average annual percentage change and its 95% CI.

Results

Globally, a large variability in the magnitude of the diagnosis of new cases of brain and CNS cancer was found, with a 5-fold difference between the highest rates (mainly in Europe) and the lowest (mainly in Asia). Increasing rates of brain and CNS cancer were found in South America, namely in Ecuador, Brazil, and Colombia; in eastern Europe (Czech Republic and Russia), in southern Europe (Slovenia), and in the 3 Baltic countries. Trends were similar between sexes, although decreasing trends in men and women were seen in Japan and New Zealand.

Conclusions

Important regional variations in brain and CNS cancers exist, and given an increasing burden and risk worldwide, there is a need for further etiological research that focuses on the elucidation of environmental risk. The trends are sufficiently complex and diffuse, however, to warrant a cautious approach to interpretation.

Vascular Endothelial Growth Factor as an Angiogenic Marker in Malignant Astrocytoma and Oligodendroglioma: An Indian Scenario

INTRODUCTION

The role of Vascular Endothelial Growth Factor (VEGF) in angiogenesis has been extensively studied in gliomas, such as astrocytoma and oligodendrogliomas, worldwide. However, there is limited information available with regard to the Indian population.

AIM

To study, whether VEGF is expressed in the Indian population in a pattern similar to that in other population.

MATERIALS AND METHODS

In this prospective study approved by the Institute Ethics Committee for Human Studies at Jawaharlal Institute of Post Graduate Medical Education and Research (JIPMER) the patients operated for glioma in 2014 and 2015 (n = 60) were included. Tumours were graded as per the World Health Organization (WHO) grading system. VEGF expression in various grades was analysed using immunohistochemistry.

RESULTS

Of the 60 patients included in this study, 15 were Grade II- (diffuse astrocytomas - 12; oligodendrogliomas- 3), 15 were Grade III-(anaplastic astrocytomas- 2; anaplastic oligodendrogliomas - 13) and 30 were Grade IV-glioblastomas. For VEGF antibody staining, two patients (3.33%) showed negative results and 58 patients (96%) showed positive results. VEGF positivity was 100% in Grade II and III, while it was 93.3% (28/30) in Grade IV tumours (p=0.012).

CONCLUSION

The expression of VEGF was associated with the grade of tumour, which gradually increased from Grade II to Grade IV. We conclude that VEGF-regulated angiogenesis plays an important role in tumour progression of astrocytomas and oligodendrogliomas in the Indian population as observed worldwide.

CD103+ Cell Growth Factor Flt3L Enhances the Efficacy of Immune Checkpoint Blockades in Murine Glioblastoma Model

Glioblastoma is a lethal disease featuring a high proliferation of tumor cells, excessive angiogenesis, and heavy drug resistance. The overall survival of glioblastoma patients has been dismal, even with an intensive standard of care. Recent advances in immune checkpoint blockades are changing the treatment of cancers. However, the efficacy of immune checkpoint blockades in glioblastoma is still unclear. Here we investigated the roles of CD103⁺ cells in regulating the effect of immune checkpoint blockades in glioblastoma mouse models. Our findings indicated that the murine glioblastoma model was not sensitive to immune checkpoint blockades. Flt3L, a growth factor for CD103⁺ cells, could significantly increase the number of CD103⁺ dendritic cells in the murine glioblastoma model and, thus, sensitize murine glioblastoma to immune checkpoint blockades. Downstream analysis indicated that the Flt3L and immune checkpoint blockade combination increased the number of tumor-infiltrating CD8⁺ cells, decreased immune checkpoint expression, and therefore enhanced the antitumor immune response in the murine glioblastoma model. These findings suggested that Flt3L could enhance the efficacy of immune checkpoint blockades in glioblastoma via expanding CD103⁺ dendritic cells and downstream antitumor immune response.

LAPTM4B-35 is a novel prognostic factor for glioblastoma

Lysosome-associated protein transmembrane-4 beta (LAPTM4B)-35, a newly identified cancer-associated gene, is overexpressed in a wide variety of malignant tumors. However, studies of its expression and role in glioma have not yet been reported. This study aimed to investigate the expression and the role of LAPTM4B-35 in glioma and to assess its value as a prognostic factor. Seventy-seven glioma cases (Grade II in 18 patients, Grade III in 16 and Grade IV in 43) were immunohistochemically examined for LAPTM4B-35, pAkt, factor VIII and Ki-67 expressions. The LAPTM4B-35 expression score of Grade II gliomas was lower than those of Grade III-IV gliomas (p < 0.05), while the difference between Grade III and IV gliomas was not statistically significant. Of the 43 patients with glioblastoma (GBM), 27 (62.8%) had high LAPTM4B-35 expression, which was associated with high tumor micro-vessel density and pAkt activation. The median progression-free survival (PFS) of GBM patients with high LAPTM4B-35 expression was 5.13 months, significantly shorter than that of those with low LAPTM4B-35 expression (12.0 months, p < 0.0001). The median overall survival (OS) of GBM patients with high LAPTM4B-35 expression was 12.5 months, again significantly shorter than that of those with low LAPTM4B-35 expression (29.6 months, p < 0.0001). Multivariate analysis indicated LAPTM4B-35 to be an independent prognostic factor for PFS and OS of GBM patients. Our findings show LAPTM4B-35 to be strongly associated with tumor proliferation, tumor angiogenesis and poor outcomes of GBM patients, suggesting LAPTM4B-35 to potentially be applicable as a novel prognostic marker and even to possibly play a role in improving GBM treatment.

Silencing of Forkhead box D1 inhibits proliferation and migration in glioma cells

Despite the extensive role of Forkhead box transcription factors in the development and progression of various cancers, little is known about their role in glioma. We examined the expression and function of Forkhead box D1 (FOXD1) in glioma cell behavior and found that FOXD1 was upregulated and directly correlated with the glioma grade. Data analysis also revealed significant differences in FOXD1 expression for both gene expression profiles (GSE4290 and GSE7696) and the TCGA datasets. Additionally, decreased FOXD1 expression in U251 and U87 glioma cells caused a delay in cell growth and a disruption in colony formation. FOXD1 silencing also promoted generation of apoptotic bodies containing nuclear fragments. Cells with suppressed expression of FOXD1 markedly reduced glioma cell migration. Our results suggest that FOXD1 may serve as a novel regulator of glioblastoma cell behavior that may offer a novel target for gene targeted glioma therapies.

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.

The etiopathogenesis of diffuse low-grade gliomas

The origins of diffuse low-grade gliomas (DLGG) are unknown. Beyond some limited data on their temporal and cellular origins, the mechanisms and risk factors involved are poorly known. First, based on strong relationships between DLGG development and the eloquence of brain regions frequently invaded by these tumors, we propose a "functional theory" to explain the origin of DLGG. Second, the biological pathways involved in DLGG genesis may differ according to tumor location (anatomo-molecular correlations). The cellular and molecular mechanisms of such "molecular theory" will be reviewed. Third, the geographical distribution of diffuse WHO grade II-III gliomas within populations is heterogeneous, suggesting possible environmental risk factors. We will discuss this "environmental theory". Finally, we will summarize the current knowledge on genetic susceptibility in gliomas ("genetic predisposition theory"). These crucial issues illustrate the close relationships between the pathophysiology of gliomagenesis, the anatomo-functional organization of the brain, and personalized management of DLGG patients.

Dec1 expression predicts prognosis and the response to temozolomide chemotherapy in patients with glioma

Differentiated embryo chondrocyte expressed gene 1 (Dec1), a crucial cell differentiation mediator and apoptosis inhibitor, is abundantly expressed in various types of human cancer and is associated with malignant tumor progression. As poor differentiation and low apoptosis are closely associated with poor survival rates and a poor response to radio/chemotherapy in patients with cancer, the prognostic value of Dec1 expression was examined in the present study and its correlation with response to temozolomide (TMZ) chemotherapy was analyzed in patients with glioma. Dec1 expression was analyzed by immunohistochemistry in 157 samples of newly diagnosed glioma and 63 recurrent glioblastoma cases that relapsed during TMZ chemotherapy. Correlations with clinical variables, prognosis and the response to TMZ chemotherapy were analyzed in the newly diagnosed gliomas. Dec1 expression was also compared with the apoptosis index determined by TdT‑mediated dUTP nick ending‑labeling assay in recurrent glioblastomas. The antiglioma effect of TMZ in nude mice xenografts with Dec1 expression was examined in vivo. High expression of Dec1, which was significantly associated with high pathological tumor grade and poor response to TMZ chemotherapy, was demonstrated to be an unfavorable independent prognostic factor and predicted poor survival in patients with newly diagnosed glioma. In patients with recurrent glioblastoma, there was a negative correlation between Dec1 expression and the apoptotic index. In nude mice treated with TMZ, Dec1 overexpression potentiated proliferation, but attenuated TMZ‑induced apoptosis. In conclusion, Dec1 is a prognostic factor for the clinical outcome and a predictive factor for the response to TMZ chemotherapy in patients with glioma.

MicroRNA-584-3p, a novel tumor suppressor and prognostic marker, reduces the migration and invasion of human glioma cells by targeting hypoxia-induced ROCK1

Here, we report that microRNA-584-3p (miR-584-3p) is up-regulated in hypoxic glioma cells and in high-grade human glioma tumors (WHO grades III–IV) relative to normoxic cells and to low-grade tumors (WHO grades I–II), respectively. The postoperative survival time was significantly prolonged in the high-grade glioma patients with high miR-584-3p expression compared with those with low miR-584-3p expression. miR-584-3p may function as a potent tumor suppressor and as a prognostic biomarker for malignant glioma. However, the molecular mechanisms underlying these properties remain poorly understood. Our mechanistic studies revealed that miR-584-3p suppressed the migration and invasion of glioma cells by disrupting hypoxia-induced stress fiber formation. Specifically, we have found that ROCK1 is a direct and functionally relevant target of miR-584-3p in glioma cells. Our results have demonstrated a tumor suppressive function of miR-584-3p in glioma, in which it inhibits the migration and invasion of tumor cells by antagonizing hypoxia-induced, ROCK1-dependent stress fiber formation. Our findings have potential implications for glioma gene therapy and suggest that miR-584-3p could represent a prognostic indicator for glioma.

AIB1 Genomic Amplification Predicts Poor Clinical Outcomes in Female Glioma Patients

Amplified in breast cancer 1 (AIB1) gene, a coactivator for steroid receptor, is frequently amplified in diverse cancers and is considered as an oncogene in tumorigenesis. However, the prognostic significance of AIB1 amplification in gliomas remains totally unclear. In this study, 115 gliomas and 16 benign meningiomas as control subjects were enrolled, and the copy number of AIB1 was analyzed in these samples. In addition, we explored potential correlation of AIB1 amplification with clinicopathological characteristics and clinical outcomes of glioma patients. Our data showed that glioma samples exhibited a significantly higher AIB1 copy number than control subjects as determined by quantitative polymerase chain reaction (qPCR) approach. Moreover, univariate analysis showed that AIB1 amplification (≥3.5 copies) was strongly correlated with cancer-related death (P =0.03). Interestingly, our data revealed a significant association of AIB1 amplification with WHO grade (P =0.03), tumor recurrence (P =0.03) and survival status (P =0.03) in female patients but not in male patients. Multivariate analysis further demonstrated that AIB1 amplification was independent factor for cancer-related death in female patients. Importantly, AIB1 amplification was closely relevant to worse survival in female patients (P =0.001), but not in male patients (P =1.00). In addition, the patients with AIB1 amplification were resistant to radiotherapy. Altogether, our data demonstrate that AIB1 amplification is a common genetic event in glioma tumorigenesis, and suggest that AIB1 amplification is not only a prognostic factor for poor clinical outcomes in glioma patients, but also a predictor of radiotherapy resistance in gliomas.

Lentivirus-mediated silencing of HSDL2 suppresses cell proliferation in human gliomas

Gliomas are the most common type of malignant brain tumors, and the related prognosis is poor. Though many genes have been identified as factors in the development and progression of gliomas, underlying mechanisms remained unclear. It was clear that abnormal lipid metabolism was one of the major hallmarks of cancers. However, few factors associated with lipid metabolism have been reported to be involved in cancer pathogenesis. Hydroxysteroid dehydrogenase-like 2 (HSDL2) is a protein containing sterol carrier protein 2 (SCP2) domain localized in peroxisomes, which indicated that HSDL2 might be a fatty acid regulatory factor. Here, we revealed that HSDL2 was significantly upregulated in gliomas and its expression was positively correlated with glioma grades. Furthermore, lentiviral-mediated HSDL2 knockdown showed that HSDL2 downregulation inhibited the proliferation in two human glioblastoma cell lines U-251 cells and U87 MG cells, induced cell cycle arrest, and promoted cell apoptosis. Our study provided multiple lines of evidence for the causal relationship between HSDL2 overexpression and glioma progression and provided possible mechanisms underlying HSDL2-mediated glioma growth. Taken together, these results indicated that HSDL2 might serve as a potential target for glioma treatment in the future.

Inhibition of monocarboxylate transporter 1 suppresses the proliferation of glioblastoma stem cells

Recent evidence suggests that a minor subset of cancer cells, termed cancer stem cells (CSCs), have self-renewal and tumorigenic potential. Therefore, the characterization of CSCs is important for developing therapeutic strategies against cancer. Cancer cells rely on anaerobic glycolysis to produce ATP even under normoxic conditions, resulting in the generation of excess acidic substances. Cancer cells maintain a weakly alkaline intracellular pH to support functions. Glioblastoma is an aggressive malignancy with a poor 5-year survival rate. Based on the hypothesis that ion transport-related molecules regulate the viability and function of CSCs, we investigated the expression of ion transport-related molecules in glioblastoma CSCs (GSCs). Quantitative RT-PCR analysis showed that monocarboxylate transporter1 (MCT1) were upregulated in GSCs, and inhibition of MCT1 decreased the viability of GSCs compared with that of non-GSCs. Our findings indicate that MCT1 is involved in the maintenance of GSCs and is a promising therapeutic target for glioblastoma.

405 nm versus 633 nm for protoporphyrin IX excitation in fluorescence-guided stereotactic biopsy of brain tumors

Fluorescence diagnosis may be used to improve the safety and reliability of stereotactic brain tumor biopsies using biopsy needles with integrated fiber optics. Based on 5-aminolevulinic-acid-induced protoporphyrin IX (PpIX) fluorescence, vital tumor tissue can be localized in vivo during the excision procedure to reduce the number of necessary samples for a reliable diagnosis. In this study, the practical suitability of two different PpIX excitation wavelengths (405 nm, 633 nm) was investigated on optical phantoms. Violet excitation at 405 nm provides a 50-fold higher sensitivity for the bulk tumor; this factor increases up to 100 with decreasing fluorescent volume as shown by ray tracing simulations. Red excitation at 633 nm, however, is noticeably superior with regard to blood layers obscuring the fluorescence. Experimental results on the signal attenuation through blood layers of well-defined thicknesses could be confirmed by ray tracing simulations. Typical interstitial fiber probe measurements were mimicked on agarose-gel phantoms. Even in direct contact, blood layers of 20-40 µm between probe and tissue must be expected, obscuring 405-nm-excited PpIX fluorescence almost completely, but reducing the 633-nm-excited signal only by 25.5%. Thus, 633 nm seems to be the wavelength of choice for PpIX-assisted detection of high-grade gliomas in stereotactic biopsy. PpIX signal attenuation through clinically relevant blood layers for 405 nm (violet) and 633 nm (red) excitation.

Acylglycerol kinase functions as an oncogene and an unfavorable prognostic marker of human gliomas

Acylglycerol kinase (AGK) regulates various cellular processes involved into tumorigenesis and tumor progression. To investigate involvement of AGK in human gliomas, here, quantitative real-time polymerase chain reaction, Western blot, and immunohistochemistry analyses were performed to respectively detect the expression of AGK mRNA and protein in glioma and nonneoplastic brain tissue specimens. Then, the associations of AGK expression with various clinicopathological characteristics and patients' prognosis were statistically evaluated. Moreover, the effects of siRNA-mediated AGK knockdown on glioma cell proliferation, migration, and invasion were respectively assessed via Cell Counting Kit-8 and Transwell assays in vitro. As a result, AGK expression, at both mRNA and protein levels, were markedly up-regulated in glioma tissues compared with nonneoplastic brain tissues (both P < .001). In addition, high AGK expression was significantly associated with the grade of malignancy and poor prognosis in glioma patients (all P < .05). Importantly, Cox regression model of multivariate analysis identified AGK expression as an independent prognostic factor for glioma patients (P = .03). Furthermore, silencing the expression of AGK dramatically suppressed cell proliferation, migration, and invasion of glioma cells in vitro (all P < .05). In conclusion, AGK up-regulation may be involved into glioma development and progression, highlighting its prognostic value for the treatment of patients with this malignancy. Further loss-of-function experiments suggest that AGK might play an important role in the viability and motility of glioma cells, implying its potentials as an attractive therapeutic target for this tumor.

Inhibition of DNA-repair genes Ercc1 and Mgmt enhances temozolomide efficacy in gliomas treatment: a pre-clinical study

Gliomas are the most common primary brain tumors. To date, therapies do not allow curing patients, and glioblastomas (GBMs) are associated with remarkably poor prognosis. This situation is at least partly due to intrinsic or acquired resistance to treatment, especially to chemotherapy. In 2005, temozolomide (TMZ) has become the first chemotherapeutic drug validated for GBM. Nevertheless TMZ efficacy depends on Mgmt status. While the methylation of Mgmt promoter was considered so far as a prognostic marker, its targeting is becoming an effective therapeutic opportunity. Thus, arrival of both TMZ and Mgmt illustrated that considerable progress can still be realized by optimizing adjuvant chemotherapy. A part of this progress could be accomplished in the future by overcoming residual resistance. The aim of the present study was to investigate the involvement of a set of other DNA-repair genes in glioma resistance to temozolomide. We focused on DNA-repair genes located in the commonly deleted chromosomal region in oligodendroglioma (1p/19q) highly correlated with patient response to chemotherapy. We measured effects of inhibition of ten DNA-repair genes expression using siRNAs on astrocytoma cell response to cisplatin (CDDP) and TMZ. SiRNAs targeting ercc1, ercc2, mutyh, and pnkp significantly sensitized cells to chemotherapy, increasing cell death by up to 25%. In vivo we observed a decrease of subcutaneous glioma tumor growth after injection of siRNA in conjunction with absorption of TMZ. We demonstrated in this pre-clinical study that targeting of DNA-repair genes such as Ercc1 could be used as an adjuvant chemosensitization treatment, similarly to Mgmt inhibition.

Insomnia and its associations in patients with recurrent glial neoplasms

Background

Patient with neurological disorders and cancer can develop sleep disturbance, in particular insomnia. Etiology of insomnia is multi-factorial in primary brain tumour patients with possible causes including corticosteroids, psychoactive medications, co-morbid psychiatric/medical conditions, and damage to neuronal tissue.

Findings

To understand better insomnia in recurrent glioma patients, a single-center retrospective analysis was performed looking at recurrent glioma patients from January 2004 to May 2009. Data was extracted and included demographics, clinical factors, psychoactive medications, and co-morbid symptoms. Presence and absence of insomnia complaints was evaluated with other co-morbidities using Chi square and Wilcoxon analyses. Records from 340 recurrent glioma patients were evaluated and 46.8 % (n = 159) indicated presence of insomnia with 20 % (n = 66) actively using medications for sleep. Use of corticosteroids were significantly associated with insomnia (p = 0.0003). Age, gender, tumour location, use of stimulants, antipsychotics, and antidepressants were not significantly associated with insomnia in recurrent glioma patients. There was a trend towards a possible significant association with insomnia to fatigue complaints and use of anti-epileptics, p-values of 0.0501 and 0.0725 respectively.

Conclusions

In conclusion, insomnia is commonly encountered in patients with recurrent glial tumors. Corticosteroid use is associated with insomnia in this population. In light of the frequency of insomnia and its associations, future analysis is warranted into sleep complaints in recurrent glioma patients and its impact on quality of life.

Roles of microRNA-99 family in human glioma

Objective

Deregulation of microRNA (miR)-99 family members (miR-99a, miR-99b, and miR-100) has been reported to play a crucial role in many cancer types. However, their roles in human gliomas have not been fully elucidated. This study aimed to investigate the expression patterns of miR-99a, miR-99b, and miR-100 in glioma tissues and to evaluate their expression profiles with respect to tumor progression.

Methods

Quantitative real-time polymerase chain reaction was performed to detect the expression levels of miR-99a, miR-99b, and miR-100 in glioma and matched non-neoplastic brain tissues. Then, the associations of their expression with various clinicopathological features of glioma patients were statistically analyzed. Moreover, the roles of miR-99a, miR-99b, and miR-100 in regulating glioma cell migration and invasion were determined via transwell assay in vitro.

Results

Compared with non-neoplastic brain tissues, miR-99a, miR-99b, and miR-100 expression levels were all significantly decreased in glioma tissues (all P<0.001). miR-99a-low, miR-99b-low, and miR-100-low expression more frequently occurred in glioma patients with low Karnofsky performance score (<90) and high World Health Organization grade (III–IV). Further functional experiments revealed that the enforced expression of miR-99a, miR-99b, and miR-100 resulted in the inhibition of cellular migration and invasion in glioma cells.

Conclusion

Our results strongly suggest that the aberrant expression of miR-99a, miR-99b, and miR-100 may be a common feature in human gliomas with aggressive clinicopathological features and may participate in malignant phenotypes of the tumors. These findings highlight the potential of the three miR-99 family members as novel therapeutic targets for human gliomas.

MiR-19a promotes cell proliferation and invasion by targeting RhoB in human glioma cells

MicroRNA-19a (miR-19a) is upregulated in different types of cancers, including gliomas, but its specific role and function in gliomas have yet to be fully elucidated. In this study, we found that miR-19a was significantly upregulated in human glioma tissues and cell lines. Overexpression of miR-19a by a miR-19a mimic promoted glioma cell proliferation and invasion. In contrast, miR-19a inhibitor suppressed cell proliferation and invasion. Furthermore, by a dual-luciferase reporter assay and expression analysis, we determined that Ras homolog family member B was a direct target of miR-19a. Knockdown of Ras homolog family member B could block cell proliferation and invasion induced by the miR-19a mimic. In conclusion, our study demonstrated that miR-19a upregulation is common in gliomas and that suppression of miR-19a expression inhibits cell proliferation and invasion, which indicates that miR-19a may act as an oncogene in gliomas.

CREBRF is a potent tumor suppressor of glioblastoma by blocking hypoxia-induced autophagy via the CREB3/ATG5 pathway

Hypoxia induces protective autophagy in advanced glioblastoma cells, and targeting this process may improve the outcome for glioblastoma patients. Recent studies have suggested that the autophagic process is upregulated in glioblastoma cells in response to extensive hypoxia. Here, we describe a novel tumor suppressor in glioblastoma cells, whereby hypoxia downregulated CREBRF expression and acts as a potent inhibitor of autophagy in glioblastoma cells via the CREB3/ATG5 pathway. Our results demonstrate that CREBRF expression negatively correlates with autophagic and HIF-1α levels in different grade gliomas. Given that CREBRF is a negative regulator of CREB3, CREB3 knockdown also repressed hypoxia-induced autophagy in glioblastoma cells in vitro. Collectively, our findings provide new insight into the molecular mechanisms underlying hypoxia-induced glioblastoma cell autophagy and indicate that the hypoxia/CREBRF/CREB3/ATG5 pathway plays a central role in malignant glioma progression.

A novel tumor-promoting mechanism of IL6 and the therapeutic efficacy of tocilizumab: Hypoxia-induced IL6 is a potent autophagy initiator in glioblastoma via the p-STAT3-MIR155-3p-CREBRF pathway

Hypoxia induces protective autophagy in glioblastoma cells and new therapeutic avenues that target this process may improve the outcome for glioblastoma patients. Recent studies have suggested that the autophagic process is upregulated in glioblastomas in response to extensive hypoxia. Hypoxia also induces the upregulation of a specific set of proteins and microRNAs (miRNAs) in a variety of cell types. IL6 (interleukin 6), an inflammatory autocrine and paracrine cytokine that is overexpressed in glioblastoma, has been reported to be a biomarker for poor prognosis because of its tumor-promoting effects. Here, we describe a novel tumor-promoting mechanism of IL6, whereby hypoxia-induced IL6 acts as a potent initiator of autophagy in glioblastoma via the phosphorylated (p)-STAT3-MIR155-3p pathway. IL6 and p-STAT3 levels correlated with the abundance of autophagic cells and HIF1A levels in human glioma tissues and with the grade of human glioma, whereas inhibition of exogenous or endogenous IL6 repressed autophagy in glioblastoma cells in vitro. Knockdown of endogenous MIR155-3p inhibited IL6-induced autophagy, and enforced expression of MIR155-3p restored the anti-autophagic activity of IL6 inhibitors. We show that the hypoxia-IL6-p-STAT3-MIR155-3p-CREBRF-CREB3-ATG5 pathway plays a central role in malignant glioma progression, with blockade of the IL6 receptor by tocilizumab demonstrating a certain level of therapeutic efficacy in a xenograft model in vivo, especially in combination with temozolomide. Moreover, tocilizumab inhibits autophagy by promoting tumor apoptosis. Collectively, our findings provide new insight into the molecular mechanisms underlying hypoxia-induced glioma cell autophagy and point toward a possible efficacious adjuvant therapy for glioblastoma patients.

Clinical prognostic factors in adults with astrocytoma: Historic cohort

OBJECTIVE

To explore the clinical prognostic factors for adults affected with astrocytoma.

PATIENTS AND METHODS

Using a historic cohort, we selected 155 clinical files from patients with astrocytoma using simple randomization. The main outcome variable was overall survival time. To identify clinical prognostic factors, we used bivariate analysis, Kaplan Meier, the log rank test and the Cox regression models. The number of lost years lived with disability (DALY) based on prevalence, was calculated.

RESULTS

The mean age at diagnosis was 45.7 years. Analysis according to tumour stage, including grades II, III and IV, also showed a younger age of presentation. Kaplan-Meier survival estimates showed that tumour grade, Karnofsky status (KPS) ≥70, resection type, chemotherapy, radiotherapy, alcohol consumption, familial history of cancer and clinical presentation were significantly associated with survival time. Using a proportional hazard model, age, grade IV, resection, chemotherapy+radiotherapy and KPS were identified as prognostic factors.The amount of life lost due to premature death in this population was 28 years.

CONCLUSION

In our study, astrocytoma was diagnosed in young adults. The overall survival was 15 months, 9% (n=14) of patients presented a survival of 2 years, and 3% of patients survived 3 years. On average the number of years lost due to premature death and disability was 28.53 years.

Targeting miR-381-NEFL axis sensitizes glioblastoma cells to temozolomide by regulating stemness factors and multidrug resistance factors

MicroRNA-381 (miR-381) is a highly expressed onco-miRNA that is involved in malignant progression and has been suggested to be a good target for glioblastoma multiforme (GBM) therapy. In this study, we employed two-dimensional fluorescence differential gel electrophoresis (2-D DIGE) and MALDI–TOF/TOF-MS/MS to identify 27 differentially expressed proteins, including the significantly upregulated neurofilament light polypeptide (NEFL), in glioblastoma cells in which miR-381 expression was inhibited. We identified NEFL as a novel target molecule of miR-381 and a tumor suppressor gene. In human astrocytoma clinical specimens, NEFL was downregulated with increased levels of miR-381 expression. Either suppressing miR-381 or enforcing NEFL expression dramatically sensitized glioblastoma cells to temozolomide (TMZ), a promising chemotherapeutic agent for treating GBMs. The mechanism by which these cells were sensitized to TMZ was investigated by inhibiting various multidrug resistance factors (ABCG2, ABCC3, and ABCC5) and stemness factors (ALDH1, CD44, CKIT, KLF4, Nanog, Nestin, and SOX2). Our results further demonstrated that miR-381 overexpression reversed the viability of U251 cells exhibiting NEFL-mediated TMZ sensitivity. In addition, NEFL-siRNA also reversed the proliferation rate of U251 cells exhibiting locked nucleic acid (LNA)-anti-miR-381-mediated TMZ sensitivity. Overall, the miR-381-NEFL axis is important for TMZ resistance in GBM and may potentially serve as a novel therapeutic target for glioma.

MicroRNA-134 modulates glioma cell U251 proliferation and invasion by targeting KRAS and suppressing the ERK pathway

Dysregulated microRNA-134 (miR-134) has been observed in glioma carcinogenesis, and studies suggested that the ERK pathway plays vital roles in glioma cell growth and proliferation. However, the fundamental relationship between miR-134 and the ERK pathway in glioma has not been fully explained. As a result, this study was aimed to explore the underlying functions of miR-134 in human glioma. Intentionally overexpressed or inhibited miR-134 expression resulted from the transfection of miR-134 mimics, or miR-134 inhibitor within glioma cell line U251 was detected using RT-PCR. Both cell counting kit-8 (CCK-8) assays and Transwell assays were carried out to clarify the proliferation and invasion of U251 cells transfected with miR-134 mimics or miR-134 inhibitors. Our findings showed that miR-134 was significantly downexpressed in glioma tissues, and low miR-134 expression was significantly related to high histopathological grades. However, upregulated miR-134 expression restrained the proliferation and invasion of U251 cells in vitro. Kirsten rat sarcoma viral oncogene (KRAS), a vital factor for the ERK pathway, was directly targeted by miR-134 through its binding with the 3'-UTR of KRAS in glioma. Furthermore, KRAS expression exhibited a positive correlation with the activity of the ERK pathway. Overexpression of KRAS without 3'-UTR partly offsets the suppressive effect of miR-134 on glioma progression. Our data also indicated that miR-134 negatively modulated glioma progression and upregulated miR-134 triggered aberrant activation of the ERK pathway by targeting KRAS. Therefore, miR-134 might be considered as a benign therapeutic target of glioma.

MMP-9 in translation: from molecule to brain physiology, pathology, and therapy

Matrix metalloproteinase-9 (MMP-9) is a member of the metzincin family of mostly extracellularly operating proteases. Despite the fact that all of these enzymes might be target promiscuous, with largely overlapping catalogs of potential substrates, MMP-9 has recently emerged as a major and apparently unique player in brain physiology and pathology. The specificity of MMP-9 may arise from its very local and time-restricted actions, even when released in the brain from cells of various types, including neurons, glia, and leukocytes. In fact, the quantity of MMP-9 is very low in the naive brain, but it is markedly activated at the levels of enzymatic activity, protein abundance, and gene expression following various physiological stimuli and pathological insults. Neuronal MMP-9 participates in synaptic plasticity by controlling the shape of dendritic spines and function of excitatory synapses, thus playing a pivotal role in learning, memory, and cortical plasticity. When improperly unleashed, MMP-9 contributes to a large variety of brain disorders, including epilepsy, schizophrenia, autism spectrum disorder, brain injury, stroke, neurodegeneration, pain, brain tumors, etc. The foremost mechanism of action of MMP-9 in brain disorders appears to be its involvement in immune/inflammation responses that are related to the enzyme's ability to process and activate various cytokines and chemokines, as well as its contribution to blood-brain barrier disruption, facilitating the extravasation of leukocytes into brain parenchyma. However, another emerging possibility (i.e., the control of MMP-9 over synaptic plasticity) should not be neglected. The translational potential of MMP-9 has already been recognized in both the diagnosis and treatment domains. The most striking translational aspect may be the discovery of MMP-9 up-regulation in a mouse model of Fragile X syndrome, quickly followed by human studies and promising clinical trials that have sought to inhibit MMP-9. With regard to diagnosis, suggestions have been made to use MMP-9 alone or combined with tissue inhibitor of matrix metalloproteinase-1 or brain-derived neurotrophic factor as disease biomarkers. MMP-9, through cleavage of specific target proteins, plays a major role in synaptic plasticity and neuroinflammation, and by those virtues contributes to brain physiology and a host of neurological and psychiatric disorders. This article is part of the 60th Anniversary special issue.

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.

Anti-glioma activity and the mechanism of cellular uptake of asiatic acid-loaded solid lipid nanoparticles

Asiatic acid (AA), a pentacyclic triterpene found in Centella Asiatica, has shown neuroprotective and anti-cancer activity against glioma. However, owing to its poor aqueous solubility, effective delivery and absorption across biological barriers, in particular the blood brain barrier (BBB), are challenging. Solid lipid nanoparticles (SLNs) have shown a promising potential as a drug delivery system to carry lipophilic drugs across the BBB, a major obstacle in brain cancer therapy. Nevertheless, limited information is available about the cytotoxic mechanisms of nano-lipidic carriers with AA on normal and glioma cells. This study assessed the anti-cancer efficacy of AA-loaded SLNs against glioblastoma and their cellular uptake mechanism in comparison with SVG P12 (human foetal glial) cells. SLNs were systematically investigated for three different solid lipids; glyceryl monostearate (MS), glyceryl distearate (DS) and glyceryl tristearate (TS). The non-drug containing MS-SLNs (E-MS-SLNs) did not show any apparent toxicity towards normal SVG P12 cells, whilst the AA-loaded MS-SLNs (AA-MS-SLNs) displayed a more favourable drug release profile and higher cytotoxicity towards U87 MG cells. Therefore, MS-SLNs were chosen for further in vitro studies. Cytotoxicity studies of SLNs (± AA) were performed using MTT assay where AA-SLNs showed significantly higher cytotoxicity towards U87 MG cells than SVG P12 normal cells, as confirmed by flow cell cytometry. Cellular uptake of SLNs also appeared to be preferentially facilitated by energy-dependent endocytosis as evidenced by fluorescence imaging and flow cell cytometry. Using the Annexin V-PI double staining technique, it was found that these AA-MS-SLNs displayed concentration-dependent apoptotic activity on glioma cells, which further confirms the potential of exploiting these AA-loaded MS-SLNs for brain cancer therapy.

Current trends in the management of glioblastoma in a French University Hospital and associated direct costs

WHAT IS NEW AND OBJECTIVES

Trends in the care of glioblastoma in actual practice settings are poorly described. In a previous pharmacoepidemiologic study, we highlighted changes in the management of patients with glioblastoma (GBM) newly diagnosed between 2004 and 2008. Our aim was to complete and to extend the previous report with a study of a cohort of patients diagnosed in 2011 to emphasize the trends in the pharmacotherapy of GBM over the last decade.

METHODS

A single-centre study was undertaken of three historic cohorts of GBM patients newly diagnosed during years 2004, 2008 and 2011 (corresponding to groups 1, 2 and 3, respectively) but limited to patients eligible for radiotherapy after initial diagnosis. The type of medical management was described and compared, as well as overall survival and total cost from diagnosis to death or the last follow-up date. Cost analysis was performed from the French sickness fund perspective using tariffs from 2014.

RESULTS

Two hundred and seventeen patients (49 in Group 1, 73 in Group 2, 95 in Group 3) were selected with similar baseline characteristics. Fluorescence-guided surgery using 5-ALA was increasingly used over the three periods. There was a strong trend towards broader use of temozolomide radiochemotherapy (39%, 73% and 83% of patients, respectively) as first-line treatment as well as bevacizumab regimen at recurrence (6%, 48% and 58% of patients, respectively). The increase in overall survival between Group 2 and Group 1 was confirmed for patients in Group 3 (17·5 months vs. 10 months in Group 1). The mean total cost per patient was 53368 € in Group 1, 70 201 € in Group 2 and 78355 € in Group 3. Hospital care represented the largest expenditure (75%, 59% and 60% in groups 1, 2 and 3, respectively) followed by chemotherapy drug costs (11%, 30% and 29%, respectively).

WHAT IS NEW AND CONCLUSION

This is the first study to report on changes in the management of GBM in real-life practice. The ten-year study indicates an improvement in overall survival but also an increase in total cost of care. The data should be useful for informing the care of GBM patients in settings similar to ours.

MicroRNA-Let-7f reduces the vasculogenic mimicry of human glioma cells by regulating periostin-dependent migration

The present study was the first to examine the effect of microRNA-Let-7f (miR-Let-7f) inhibiting vasculogenic mimicry (VM) of human glioma cells. The postoperative survival time was significantly poor in VM-positive glioma patients compared with those without VM. Thus, it is reasonable to postulate that miR-Let-7f functions as a potent tumor suppressor by inhibiting glioma VM. However, the molecular mechanisms involved remain poorly clarified. Our preliminary studies revealed that miR-Let-7f suppressed VM by disturbing periostin (POSTN)-induced migration of glioma cells. Our results clearly demonstrated that inhibiting the pro-migratory function of POSTN by the overexpression of miR-Let-7f significantly reduced the formation of VM. Our findings suggest that miR-Let-7f may serve as a potential complementary therapeutic target in the anti‑angiogenesis treatment of gliomas via suppressing VM.

Synergism between cryoablation and GM-CSF: enhanced immune function of splenic dendritic cells in mice with glioma

Glioma is the most common malignant primary brain tumor, and it has a poor prognosis. Studies have shown that cryoablation can activate antitumor immunoeffects by promoting the augmentation of dendritic cells (DCs). Granulocyte macrophage colony-stimulating factor (GM-CSF) has been shown to be useful for immunotherapy against glioma because it can stimulate DCs to present tumor antigen. Previous studies have shown that cryoablation and GM-CSF can exert antitumor effects. To test the hypothesis that combined therapy with cryoablation and GM-CSF for glioma could synergistically improve specific antiglioma immunity in mice, we tested the validity of this assumption in a murine subcutaneous GL261 glioma model. C57BL/6 mice with subcutaneous GL261 glioma were created and divided into four groups: no treatment, GM-CSF injection, cryoablation treatment, and GM-CSF and cryoablation combined treatment (n=20 in each group). Serial immune indicators were detected at sequential time points during treatment. Compared with the other groups, in the combined treatment group, DCs were more activated and their numbers were markedly upregulated, the secretion of interferon-γ from Th1 cells of mice spleen was increased, and the cytolytic activity of CD8 CTLs exerted a more significant cytotoxic effect on GL261 glioma cells (P<0.05 for all). Furthermore, these changes peaked on the 7th day after treatment, and then gradually reduced, until the 21st day; these changes were higher than those at pretreatment (P<0.05). It is concluded that combined therapy with argon-helium cryoablation and GM-CSF could synergistically enhance the activation of DCs and induce a robust tumor-specific immunologic response in glioma-bearing mice.