Glioma biology and molecular markers

OSlgg: An Online Prognostic Biomarker Analysis Tool for Low-Grade Glioma

Glioma is the most frequent primary brain tumor that causes high mortality and morbidity with poor prognosis. There are four grades of gliomas, I to IV, among which grade II and III are low-grade glioma (LGG). Although less aggressive, LGG almost universally progresses to high-grade glioma and eventual causes death if lacking of intervention. Current LGG treatment mainly depends on surgical resection followed by radiotherapy and chemotherapy, but the survival rates of LGG patients are low. Therefore, it is necessary to use prognostic biomarkers to classify patients into subgroups with different risks and guide clinical managements. Using gene expression profiling and long-term follow-up data, we established an Online consensus Survival analysis tool for LGG named OSlgg. OSlgg is comprised of 720 LGG cases from two independent cohorts. To evaluate the prognostic potency of genes, OSlgg employs the Kaplan-Meier plot with hazard ratio and p value to assess the prognostic significance of genes of interest. The reliability of OSlgg was verified by analyzing 86 previously published prognostic biomarkers of LGG. Using OSlgg, we discovered two novel potential prognostic biomarkers (CD302 and FABP5) of LGG, and patients with the elevated expression of either CD302 or FABP5 present the unfavorable survival outcome. These two genes may be novel risk predictors for LGG patients after further validation. OSlgg is public and free to the users at http://bioinfo.henu.edu.cn/LGG/LGGList.jsp.

Role of molecular biomarkers in glioma resection: a systematic review

New discoveries based on genetic and epigenetic evidence have significantly expanded the understanding of diffuse gliomas. Molecular biomarkers detected in diffuse gliomas are not only potential targets for radiotherapy, chemotherapy, and immunotherapy, but are also able to guide surgical treatment. Previous studies have suggested that the optimal extent of resection of diffuse gliomas varies according to the expression of specific molecular biomarkers. However, the specific guiding role of these biomarkers in the resection of diffuse gliomas has not been systemically analyzed. This review summarizes several critical molecular biomarkers of tumorigenesis and progression in diffuse gliomas and discusses different strategies of tumor resection in the context of varying genetic expression. With ongoing study and advances in technology, molecular biomarkers will play a more important role in glioma resection and maximize the survival benefit from surgery for diffuse gliomas.

A Novel Highly Selective Cannabinoid CB2 Agonist Reduces in vitro Growth and TGF-beta Release of Human Glial Cell Tumors

BACKGROUND

Cannabinoid receptors have been detected in human gliomas and cannabinoids have been proposed as novel drug candidates in the treatment of brain tumors.

AIMS

To test the in vitro antitumor activity of COR167, a novel cannabinoid CB2-selective agonist displaying a high binding affinity for human CB2 receptors, on tumor cells isolated from human glioblastoma multiforme and anaplastic astrocytoma.

METHODS

Glioma cell cultures were established from two glioblastoma multiforme and two anaplastic astrocytomas. Proliferation was measured in the presence or absence of COR167 with a bromodeoxyuridine (BrdU) cell proliferation ELISA assay. CB2 receptor expression was detected by western blotting. Apoptosis was assessed with phycoerythrin (PE) annexin V flow cytometry kit. TGF-beta 1 and 2 levels were analyzed in culture supernatants with commercial ELISAs.

RESULTS

COR167 was found to significantly reduce the proliferation of both glioblastoma and anaplastic astrocytoma in a dose-dependent manner at lower doses than other known, less specific CB2 agonists. This activity is independent of apoptosis and is associated with a significant reduction of TGF-beta 1 and 2 levels in supernatants of glioma cell cultures.

CONCLUSION

These findings add to the role of cannabinoid CB2 receptor as a possible pharmacological target to counteract glial tumor growth and encourage further work to explore any other pharmacological effect of this novel CB2 agonist useful in the treatment of human gliomas.

MicroRNA-144 represses gliomas progression and elevates susceptibility to Temozolomide by targeting CAV2 and FGF7

Malignant gliomas are the most common tumor in central nervous system with poor prognosis. Due to the limitation of histological classification in earlier diagnosis and individualized medicine, it is necessary to combine the molecular signatures and the pathological characteristics of gliomas. Lots of microRNAs presented abnormal expression in gliomas and modulated gliomas development. Exploration the miRNAs profile is helpful for the diagnosis, therapy and prognosis of gliomas. It has been demonstrated that miR-144 plays important roles in solid tumors. However, the detail mechanisms remained unrevealed. In this study, we have demonstrated the level of miR-144 decreased in glioma tissues from patients, especially in gliomas with higher grades. MiR-144 was also validated have lower expression in glioma cell lines compared with cortical neuron cell by using qRT-PCR. The in vitro functional experiment indicated miR-144 improved gliomas progression through repressing proliferation, sensitizing to chemotherapeutics and inhibiting metastasis. We further identified fibroblast growth factor 7 (FGF7) and Caveolin 2 (CAV2) were target genes of miR-144 by luciferase reporter assay and western blotting. The mechanisms study suggested forced FGF7 expression elevated Akt activation and decreased reactive oxygen species (ROS) generation. The MTT and cell cycle assay indicated miR-144 suppressed glioma cells proliferation through modulating FGF mediated Akt signaling pathway. Meanwhile, miR-144 promoted Temozolomide (TMZ) induced apoptosis in glioma cells via increasing ROS production by using FACS. On the other hand, CAV2, as another target of miR-144, accelerated glioma cells migration and invasion via promoting glioma cells EMT progress. Retrieved expression of FGF7 or CAV2 rescued the proliferation and migration function mediated by miR-144. Furthermore, the in vivo experiments in PDX models displayed the anti-tumor function of miR-144, which could be retrieved by overexpression of FGF7 and CAV2. Taken together, these findings indicated miR-144 acted as a potential target against gliomas progression and uncovered a novel regulatory mechanism, which may provide a new therapeutic strategy and prognostic indicator for gliomas.

Identification of KIF15 as a potential therapeutic target and prognostic factor for glioma

Glioma is the most commonly diagnosed primary intracranial malignant tumor with rapid growth, easy recurrence and thus poor prognosis. In the present study, the role of kinesin‑12 (KIF15) in glioma was revealed. Immunohistochemical staining and western blot analysis were used to detect the protein expression. An MTT assay was performed to evaluate cell proliferation. Flow cytometric analysis was utilized to assess cell apoptosis and the cell cycle. A mouse xenograft model was constructed for in vivo study. The results indicated that KIF15 was significantly upregulated in glioma tumor tissues and positively correlated with pathological staging, recurrence risk and poor prognosis. Silencing of KIF15 could inhibit cell proliferation and stemness of glioma cells, arrest cells in the G2 phase and induce cell apoptosis. The in vivo study verified the inhibitory effect of KIF15 knockdown on tumor growth. The mechanism study demonstrated the regulation of apoptosis‑ and cycle‑related proteins in the KIF15 KD‑induced inhibition of glioma. KIF15 was revealed to function as a tumor promoter in the development and progression of glioma. KIF15 also served as a prognostic indicator for glioma and may be a therapeutic target for glioma therapy.

Targeting iNOS As a Valuable Strategy for the Therapy of Glioma

Gliomas are the most prevalent primary tumors of the brain and spinal cord. Histologically, they share features of normal glial cells, but whether gliomas originate from normal glial cells, glial or neural precursors, stem cells, or other cell types remains a topic of investigation. The enhanced expression of inducible nitric oxide synthase (iNOS) has been reported as a hallmark of chemoresistance in gliomas, and several lines of evidence have reported that a decreased proliferation of glioma cells could be related to the selective inhibition of iNOS. This review aims to summarize the current understanding of iNOS expression and activity modulation in the regulation of glioma pathogenesis, along with compounds that could act as therapeutic agents against glioma.

Comprehensive Analysis Reveals a 4-Gene Signature in Predicting Response to Temozolomide in Low-Grade Glioma Patients

Low-grade gliomas (LGGs) are a highly heterogeneous group of slow-growing, lethal, diffusive brain tumors. Temozolomide (TMZ) is a frequently used primary chemotherapeutic agent for LGGs. Currently there is no consensus as to the optimal biomarkers to predict the efficacy of TMZ, which calls for decision-making for each patient while considering molecular profiles. Low-grade glioma data sets were retrieved from The Cancer Genome Atlas. Cox regression and survival analyses were applied to identify clinical features significantly associated with survival. Subsequently, Ordinal logistic regression, co-expression, and Cox regression analyses were applied to identify genes that correlate significantly with response rate, disease-free survival, and overall survival of patients receiving TMZ as primary therapy. Finally, gene expression and methylation analyses were exploited to explain the mechanism between these gene expression and TMZ efficacy in LGG patients. Overall survival was significantly correlated with age, Karnofsky Performance Status score, and histological grade, but not with IDH1 mutation status. Using 3 distinct efficacy end points, regression and co-expression analyses further identified a novel 4-gene signature of ASPM, CCNB1, EXO1, and KIF23 which negatively correlated with response to TMZ therapy. In addition, expression of the 4-gene signature was associated with those of genes involved in homologous recombination. Finally, expression and methylation profiling identified a largely unknown olfactory receptor OR51F2 as potential mediator of the roles of the 4-gene signature in reducing TMZ efficacy. Taken together, these findings propose the 4-gene signature as a novel panel of efficacy predictors of TMZ therapy, as well as potential downstream mechanisms, including homologous recombination, OR51F2, and DNA methylation independent of MGMT.

Prognostic role of mitochondrial pyruvate carrier in isocitrate dehydrogenase-mutant glioma

OBJECTIVE Gliomas are one of the most common types of primary brain tumors. Recent studies have supported the importance of key genetic alterations, including isocitrate dehydrogenase (IDH) mutations and 1p19q codeletion, in glioma prognosis. Mutant IDH produces 2-hydroxyglutarate from α-ketoglutarate, a key metabolite of the Krebs cycle. The mitochondrial pyruvate carrier (MPC) is composed of MPC1 and MPC2 subunits and is functionally essential for the Krebs cycle. The authors sought to explore the impact of MPC1 and MPC2 expression on patient prognosis. METHODS Genomic and clinical data in patients with lower-grade glioma (WHO grades II and III) from The Cancer Genome Atlas (TCGA) were evaluated using Kaplan-Meier analysis and hazards modeling. Validation was conducted with additional data sets, including glioblastoma. RESULTS A total of 286 patients with lower-grade glioma (mean age 42.7 ± 13.5 years, 55.6% males) included 54 cases of IDH-wild type (18.9%); 140 cases of IDH-mutant, 1p19q-intact (49.0%); and 85 cases of IDH-mutant, 1p19q-codeleted (29.7%) tumors. Kaplan-Meier analysis showed that an MPC1 z-score > 0 distinguished better survival, particularly in IDH-mutant (p < 0.01) but not IDH-wild type tumors. Conversely, an MPC2 z-score > 0 identified worsened survival, particularly in IDH-mutant (p < 0.01) but not IDH-wild type tumors. Consistently, neither MPC1 nor MPC2 was predictive in a glioblastoma data set containing 5% IDH-mutant cases. Within the IDH-stratified lower-grade glioma data set, MPC1 status distinguished improved survival in 1p19q-codeleted tumors (p < 0.05), whereas MPC2 expression delineated worsened survival in 1p19q-intact tumors (p < 0.01). A hazards model identified IDH and 1p19q status, age (p = 0.01, HR = 1.03), Karnofsky Performance Scale (KPS) score (p = 0.03, HR = 0.97), and MPC1 (p = 0.003, HR = 0.52) but not MPC2 (p = 0.38) as key variables affecting overall survival. Further validation confirmed MPC1 as an independent predictor of lower-grade glioma. A clinical risk score using IDH and 1p19q status, age, KPS score, and MPC1 and MPC2 z-scores defined 4 risk categories for lower-grade glioma; this score was validated using a secondary glioma data set. CONCLUSIONS These results support the importance of MPC, especially MPC1, in improving prognostication of IDH-mutant tumors. The generation of a risk score system directly translates this finding to clinical application; however, further research to improve the molecular understanding of the role of MPC in the metabologenomic regulation of gliomas is warranted.

Normalization in Human Glioma Tissue

For tissues obtained from glioma samples with/without nonneoplastic brain there is no consensus for universal reference gene but there are some potential genes that might have good stability, under certain conditions. Considering all points described in this work, the care with tissue collection, until gene amplification, directly impacts on the reliable characterization of its mRNA levels. Moreover, it is clear the importance of selecting the most appropriate reference genes for each experimental situation, to allow the accurate normalization of target genes, especially for genes that are subtly regulated.

A novel PTPRZ1-ETV1 fusion in gliomas

The aggressive nature of malignant gliomas and their genetic and clinical heterogeneity present a major challenge in their diagnosis and treatment. Development of targeted therapy brought attention on detecting novel gene fusions, since they represent promising therapeutic targets (eg, TRK inhibitors in NTRK fusion-positive tumors). Using targeted next-generation sequencing, we prospectively analyzed 205 primary brain tumors and detected a novel PTPRZ1-ETV1 fusion transcript in 11 of 191 (5.8%) gliomas, including nine glioblastomas, one anaplastic oligodendroglioma and one pilocytic astrocytoma. PTPRZ1-ETV1 fusion was confirmed by RT-PCR followed by Sanger sequencing, and in-silico analysis predicted a potential driver role. The newly detected fusion consists of the PTPRZ1 promoter in frame with the highly conserved DNA-binding domain of ETV1 transcription factor. The ETV1 and PTPRZ1 genes are known oncogenes, involved in processes of tumor development. ETV1 is a member of the ETS family of transcription factors, already known oncogenic drivers in Ewing sarcoma, prostate cancer and gastrointestinal stromal tumors, but not in gliomas. Its overexpression contributes to tumor growth and more aggressive tumor behavior. PTPRZ1 is already considered to be a tumor growth promoting oncogene in gliomas. In 8%-16% of gliomas, PTPRZ1 is fused to the MET oncogene, resulting in a PTPRZ1-MET fusion, which is associated with poorer prognosis but is also a positive predictive biomarker for treatment with kinase inhibitors. In view of the oncogenic role that the two fusion partners, PTPRZ1 and ETV1, exhibit in other malignancies, PTPRZ1-ETV1 fusion might present a novel potential therapeutic target in gliomas. Although histopathological examination of PTPRZ1-ETV1 fusion-positive gliomas did not reveal any specific or unique pathological features, and the follow-up period was too short to assess prognostic value of the fusion, careful monitoring of patients and their response to therapy might provide additional insights into the prognostic and predictive value of this novel fusion.

An update on the management of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PNETs) are a rare and heterogeneous group of neoplasia and differ in their clinical presentation, behavior, and prognosis based on both histological features and cancer stage at the time of diagnosis. Although small-sized tumors can be surgically resected, locally advanced and metastatic tumors confer a poor prognosis. In addition, only limited treatment options are available to the latter group of patients with PNETs, such as hormonal analogs, cytotoxic agents, and targeted therapy. In selected patients, liver-directed therapies are also used. As expected, clinicians taking care of these patients are challenged to develop an effective and comprehensive treatment strategy for their patients amid a wide variety of treatment modalities. Targeted therapy for PNETs is limited to sunitinib and everolimus. Presently, a number of clinical studies are ongoing to assess the efficacy of newer targeted agents alone and in combination with previous agents for the treatment of advanced PNETs. The authors reviewed the current treatment and also discussed the emerging agents and emphasized the need to identify biomarkers.

31 gene expression-based signatures serve as indicators of prognosis for patients with glioma

Glioma has one of the highest mortality rates of all cancer types; however, the prognosis cannot be predicted effectively using clinical indicators, due to the biological heterogeneity of the disease. A total of 31 gene expression-based signatures were identified using selected features in The Cancer Genome Atlas cohorts and machine learning methods. The signatures were assayed in the training dataset and were further validated in four completely independent datasets. Association analyses were implemented, and the results indicated that the signature was not significantly associated with age, radiation therapy or primary tumor size. A nomogram for the 1-year overall survival rate of patients with glioma following initial diagnosis was plotted to facilitate the clinical utilization of the signature. Gene Set Enrichment Analysis was performed based on the signature, in order to determine the potential altered pathways. Metabolic pathways were determined to be significantly enriched. In summary, the 31 gene expression-based signatures were effective and robust in predicting the clinical outcome of glioma in 1,016 glioma samples in five independent international cohorts.

miR-526b-3p serves as a prognostic factor and regulates the proliferation, invasion, and migration of glioma through targeting WEE1

Background: MicroRNAs play important roles in cancer progression including glioma. In this study, we aimed to explore the expression pattern, prognostic potential, and functional role of miR-526b-3p in human glioma.

Materials and methods: The expression of miR-526b-3p in glioma tissues and the adjacent non-tumor tissues was determined by quantitative RT-PCR. The chi-square test was performed to evaluate the statistical associations between miR-526b-3p level and patient characteristics. The prognostic value of miR-526b-3p was analyzed by Kaplan–Meier and Cox regression analyses. The function of miR-526b-3p was analyzed by MTT, colony formation assay, transwell assay, and flow cytometry analysis in vitro. The binding between miR-526b-3p and predicted target WEE1 was verified using dual luciferase assay and Western blot analysis.

Results: We found that miR-526b-3p expression was significantly downregulated in both glioma tissues and cell lines. Downregulation of miR-526b-3p was significantly associated with advanced WHO grade, lower KPS score, and inferior patient outcomes. Functional investigation indicated that overexpression of miR-526b-3p suppressed cell proliferation, migration, and invasion, and promoted apoptosis in glioma cell lines. Mechanically, WEE1 was identified as direct targets of miR-526b-3p and overexpression of WEE1 significantly suppressed the levels of WEE1. Moreover, re-introduction of WEE1 abrogates the suppression of motility and invasiveness induced by miR-526b-3p in glioma cells.

Conclusion: These findings indicate that miR-526b-3p may target WEE1 and inhibit glioma tumorigenesis and progression.

The mechanical and pharmacological regulation of glioblastoma cell migration in 3D matrices

The invasion of glioblastoma is a complex process based on the interactions of tumor cells and the extracellular matrix. Tumors that are engineered using biomaterials are more physiologically relevant than a two-dimensional (2D) cell culture system. Matrix metalloproteinases and the plasminogen activator generated by tumor cells regulate a tumor's invasive behavior. In this study, microtumors were fabricated by encapsulating U87 glioma cells in Type I collagen and then glioma cell migration in the collagen hydrogels was investigated. Crosslinking of collagen with 8S-StarPEG increased the hydrogel viscosity and reduced the tumor cell migration speed in the hydrogels. The higher migration speed corresponded to the increased gene expression of MMP-2, MMP-9, urokinase plasminogen activator (uPA), and tissue plasminogen activator (tPA) in glioma cells grown in non-crosslinked collagen hydrogels. Inhibitors of these molecules hindered U87 and A172 cell migration in collagen hydrogels. Aprotinin and tranexamic acid did not inhibit U87 and A172 migration on the culture dish. This study demonstrated the differential effect of pharmacologic molecules on tumor cell motility in either a 2D or three-dimensional culture environment.

Huge heterogeneity in survival in a subset of adult patients with resected, wild-type isocitrate dehydrogenase status, WHO grade II astrocytomas

OBJECTIVE

World Health Organization grade II gliomas are infiltrating tumors that inexorably progress to a higher grade of malignancy. However, the time to malignant transformation is quite unpredictable at the individual patient level. A wild-type isocitrate dehydrogenase (IDH-wt) molecular profile has been reported as a poor prognostic factor, with more rapid progression and a shorter survival compared with IDH-mutant tumors. Here, the oncological outcomes of a series of adult patients with IDH-wt, diffuse, WHO grade II astrocytomas (AII) who underwent resection without early adjuvant therapy were investigated.

METHODS

A retrospective review of patients extracted from a prospective database who underwent resection between 2007 and 2013 for histopathologically confirmed, IDH-wt, non–1p19q codeleted AII was performed. All patients had a minimum follow-up period of 2 years. Information regarding clinical, radiographic, and surgical results and survival were collected and analyzed.

RESULTS

Thirty-one consecutive patients (18 men and 13 women, median age 39.6 years) were included in this study. The preoperative median tumor volume was 54 cm3 (range 3.5–180 cm3). The median growth rate, measured as the velocity of diametric expansion, was 2.45 mm/year. The median residual volume after surgery was 4.2 cm3 (range 0–30 cm3) with a median volumetric extent of resection of 93.97% (8 patients had a total or supratotal resection). No patient experienced permanent neurological deficits after surgery, and all patients resumed a normal life. No immediate postoperative chemotherapy or radiation therapy was given. The median clinical follow-up duration from diagnosis was 74 months (range 27–157 months). In this follow-up period, 18 patients received delayed chemotherapy and/or radiotherapy for tumor progression. Five patients (16%) died at a median time from radiological diagnosis of 3.5 years (range 2.6–4.5 years). Survival from diagnosis was 77.27% at 5 years. None of the 21 patients with a long-term follow-up greater than 5 years have died. There were no significant differences between the clinical, radiological, or molecular characteristics of the survivors relative to the patients who died.

CONCLUSIONS

Huge heterogeneity in the survival data for a subset of 31 patients with resected IDH-wt AII tumors was observed. These findings suggest that IDH mutation status alone is not sufficient to predict risk of malignant transformation and survival at the individual level. Therefore, the therapeutic management of AII tumors, in particular the decision to administer early adjuvant chemotherapy and/or radiation therapy following surgery, should not solely rely on routine molecular markers.

Transcriptional Repression of p53 by PAX3 Contributes to Gliomagenesis and Differentiation of Glioma Stem Cells

Although there are available therapies as surgery, chemotherapy and radiation, glioblastoma (GBM) still has been considered as the most common and overwhelming primary tumor of brain. In GBM, the brain glioma stem cells (BGSCs) were identified and played a crucial role in resistance of GBM to conventional therapies described above. PAX3 was previously identified by our group as a diagnostic/prognostic marker and a therapeutic regulator in the therapy of GBM. Here, we hypothesized PAX3/p53 axis promoted the process of differentiation, regulating to the cancer stem cell properties, such as proliferation and migration. The correlation between PAX3 and p53 in GBM were first clarified. Immunofluorescence of p53 was shown activated following BGSCs differentiation. We further identified that PAX3 might specifically bind to the promoter of p53 gene, and transcriptionally repressed p53 expression. ChIP assay further confirmed that PAX3/p53 axis regulated the differentiation process of BGSCs. Then, the function of PAX3 in BGSCs were sequentially investigated in vitro and in vivo. Ectopic PAX3 expression promoted BGSCs growth and migration while PAX3 knockdown suppressed BGSCs growth, migration in vitro and in vivo. Similar to PAX3 overexpression, p53 inhibition also showed increase in growth and migration of differentiated BGSCs. Regarding the functional interaction between PAX3 and p53, PAX3 knockdown-mediated decrease in proliferation was partially rescued by p53 inhibition. Hypoxia significantly promoted the migration potential of BGSCs. In addition, hypoxia inducible factor-1α (HIF-1α) might be a potential upstream regulator of PAX3 in differentiated BGSCs under hypoxia. Our work may provide a supplementary mechanism in regulation of the BGSCs differentiation and their functions, which should provide novel therapeutic targets for GBM in future.

Actin like-6A promotes glioma progression through stabilization of transcriptional regulators YAP/TAZ

Increased Actin-like 6A (ACTL6A) expression has been implicated in the development of diverse cancers and recently associated with the Hippo signaling pathway, which is known to regulate biological properties, including proliferation, tissue regeneration, stem cell biology, as well as tumorigenesis. Here we first show that ACTL6A is upregulated in human gliomas and its expression is associated with glioma patient survival. ACTL6A promotes malignant behaviors of glioma cells in vitro and in orthotopic xenograft model. In co-immunoprecipitation assays, we discover that ACTL6A physically associated with YAP/TAZ and furthermore disrupts the interaction between YAP and β-TrCP E3 ubiquitin ligase, which promotes YAP protein degradation. Moreover, effects of ACTL6A on glioma cells proliferation, migration, and invasion could be mediated by YAP/TAZ. These data indicate that ACTL6A may contribute to cancer progression by stabilizing YAP/TAZ and therefore provide a novel therapeutic target for the treatment of human gliomas.

Novel fluoropyrimidine-based chemotherapy for advanced well-differentiated neuroendocrine tumors: a clinical update

INTRODUCTION

Patients with advanced well-differentiated neuroendocrine tumors (NETs) who have bulky and/or symptomatic and/or rapidly progressive disease require chemotherapy treatment.

AREAS COVERED

This review summarizes the accumulating evidence for treatment with fluorouracil-based chemotherapy in well-differentiated NETs. The main clinical studies, toxicity and predictors of fluorouracil- based chemotherapy regimens in well-differentiated NETs are discussed, along with the current issues, future research directions and therapeutic prospects.

EXPERT OPINION

Somatostatin analogs may control symptoms of hormone excess and tumor growth in patients with well-differentiated metastatic NETs, and biological therapies may improve progression-free survival for these patients. However, chemotherapy leads to higher objective response rates and symptom control by reducing tumor bulk. The low response rate and significant toxicities of conventional chemotherapy regimens limit their widespread use. Fortunately, some novel fluoropyrimidine-based treatment including fluorouracil, capecitabine, or S-1 based chemotherapy with or without antiangiogenic agents have been investigated in recent years. These treatments showed significant efficacy and less toxicity in pancreatic and non-pancreatic metastatic well-differentiated NETs. Additionally, non-pancreatic well-differentiated NETs have also achieved similar tumor response or survival comparable to pancreatic NETs. Moreover, some predictors of response to these treatment regimens have been evaluated.

Repression of the expression of PPP3CC by ZEB1 confers activation of NF-κB and contributes to invasion and growth in glioma cells

Background

Gliomas are highly malignant brain tumors. Aberrant activation of NF-κB plays a crucial role in tumor progression.

Method

ELISA assay was used to detect NF-κB activity in glimoas cells with different treatments. PPP3CC expression was evaluated by qRT-PCR and western blot assay. Kaplan-Meier analysis estimated the overall survival rates according to the protein level of PPP3CC. Transwell and MTS assay were performed to determine cell invasion and growth. Chromatin immunoprecipitation combined with luciferase reporter assays illustrated the transcriptional regulation of PPP3CC.

Results

We showed that PPP3CC decrease was responsible for constitutive activation of NF-κB in gliomas. Restored PPP3CC expression inhibited activation of NF-κB. PPP3CC was frequently decreased in gliomas and that repression of the expression of PPP3CC correlated glioma progression. The ectopic expression of PPP3CC inhibited the invasive potential of glioma cells, and inhibited glioma cells proliferation in vitro and growth in vivo. Additionally, the expression of Zinc finger E-box-binding homeobox 1(ZEB1) was increased in gliomas and was negatively correlated with clinical outcomes of glioma patients. ZEB1 inversely correlated with the expression of PPP3CC. ZEB1 was also confirmed to physically bind to the PPP3CC promoter. ZEB1 knockdown resulted in an increase in the expression of PPP3CC and elevation of PPP3CC promoter activity in glioma cells.

Conclusion

These findings indicated that the down-regulation of PPP3CC by ZEB1 resulted in activation of NF-κB is a critical oncogenic event in gliomas.

Targeted nanoparticle delivery of therapeutic antisense microRNAs presensitizes glioblastoma cells to lower effective doses of temozolomide in vitro and in a mouse model

Temozolomide (TMZ) chemotherapy for glioblastoma (GBM) is generally well tolerated at standard doses but it can cause side effects. GBMs overexpress microRNA-21 and microRNA-10b, two known oncomiRs that promote cancer development, progression and resistance to drug treatment. We hypothesized that systemic injection of antisense microRNAs (antagomiR-21 and antagomiR-10b) encapsulated in cRGD-tagged PEG-PLGA nanoparticles would result in high cellular delivery of intact functional antagomiRs, with consequent efficient therapeutic response and increased sensitivity of GBM cells to lower doses of TMZ. We synthesized both targeted and non-targeted nanoparticles, and characterized them for size, surface charge and encapsulation efficiency of antagomiRs. When using targeted nanoparticles in U87MG and Ln229 GBM cells, we showed higher uptake-associated improvement in sensitivity of these cells to lower concentrations of TMZ in medium. Co-inhibition of microRNA-21 and microRNA-10b reduced the number of viable cells and increased cell cycle arrest at G2/M phase upon TMZ treatment. We found a significant increase in expression of key target genes for microRNA-21 and microRNA-10b upon using targeted versus non-targeted nanoparticles. There was also significant reduction in tumor volume when using TMZ after pre-treatment with loaded nanoparticles in human GBM cell xenografts in mice. In vivo targeted nanoparticles plus different doses of TMZ showed a significant therapeutic response even at the lowest dose of TMZ, indicating that preloading cells with antagomiR-21 and antagomiR-10b increases cellular chemosensitivity towards lower TMZ doses. Future clinical applications of this combination therapy may result in improved GBM response by using lower doses of TMZ and reducing nonspecific treatment side effects.

Serum microRNA-376 family as diagnostic and prognostic markers in human gliomas

BACKGROUND

MicroRNA (miR)-376 family play crucial roles in cancer formation and progression.

OBJECTIVE

To investigate expression patterns of circulating miR-376 members in glioma patients, and to explore their diagnostic and prognostic values.

METHODS

Expression of miR-376 members in serum samples from 100 glioma patients and 50 healthy controls were detected by quantitative real-time PCR.

RESULTS

Serum miR-376a, miR-376b and miR-376c in glioma patients were significantly lower than those in healthy controls (all P< 0.05). Their expression could efficiently distinguish the glioma patients from healthy controls according to the receiver operating characteristic (ROC) analysis [for miR-376a, the area under ROC curve (AUC) = 0.872, the optimal cut-off value = 1.95, the sensitivity = 81.0% and the specificity = 82.0%; for miR-376b, AUC = 0.890, the optimal cut-off value = 2.07, the sensitivity = 82.0% and the specificity = 78.0%; for miR-376c, AUC = 0.837, the optimal cut-off value = 2.12, the sensitivity = 90.0% and the specificity = 70.0%; all P<0. 001]. Decreased expression of miR-376a, miR-376b and miR-376c in patients' sera were significantly associated with advanced WHO grade (all P< 0.01) and low KPS (all P< 0.05). Kaplan-Meier and Cox regression analyses showed that low miR-376a, miR-376b and miR-376c expression, and high grade were all independent factors predicting poor outcome of glioma patients. Notably, subgroup analyses showed that serum miR-376a, miR-376b and miR-376c levels had more significant prognostic values in patients with high grade gliomas than those with low grade gliomas.

CONCLUSIONS

Aberrant expression of the miR-376 family may be involved into tumorigenesis and tumor progression of human gliomas. Circulating miR-376a, miR-376b and miR-376c may be promising non-invasive biomarkers for diagnosis and prognosis in glioma patients.

A study on the correlation between STAT‑1 and mutant p53 expression in glioma

Glioma is the most common primary brain tumor in adults and the second most common malignant tumor in children. Aberrant expression of signal transducer and activator of transcription 1 (STAT‑1) and p53 are known to affect the occurrence and progression of malignant tumors. The aim of the present study was to investigate the expression of STAT‑1 and mutant p53 gene, as well as their correlation, in patients with glioma. The present study included 50 patients who underwent glioma resection at the First Affiliated Hospital of Inner Mongolia Medical University between December 2007 and December 2011, and 10 patients with acute cerebral contusion who underwent intracerebral hematoma removal at the same hospital between January 2013 and January 2014. The expression of STAT‑1 and mutant p53 protein in patients with different grades of glioma was assessed by immunohistochemistry. Spearman's correlation coefficient was employed to examine the correlation between STAT‑1 and the grade of glioma, and mutant p53 expression. The results demonstrated that the mean expression of STAT‑1 in glioma was significantly lower compared with normal brain tissue (P<0.05). However, there was no significant difference in the STAT‑1 positive expression rate between the two groups (χ2=1.38, P>0.05). The expression score (P<0.05) and positive expression rate (χ2=31.27, P<0.05) of mutant p53 in glioma was significantly higher compared with those in normal brain tissue. Statistical analysis revealed a negative correlation between STAT‑1 expression and the grade of glioma (r=‑0.767, P<0.05). In addition, mutant p53 expression was negatively correlated with STAT‑1 expression in glioma (r=‑0.876, P<0.05). The observed negative correlation between STAT‑1 and the pathological grade of glioma suggested an association between STAT‑1 and the occurrence and development of glioma, thus revealing the potential of STAT‑1 as a diagnostic biomarker and therapeutic target for glioma.

Effects of dexamethasone on C6 cell proliferation, migration and invasion through the upregulation of AQP1

Dexamethasone (Dex) is commonly used to treat glioma; however, the mechanism underlying the action of Dex remains unclear. In the present study, the hypothesis that aquaporin-1 (AQP1) may participate in tumor cell proliferation, apoptosis, migration and invasion was tested using small interfering RNA (siRNA). The results of the current study indicated that Dex could inhibit the proliferation, in addition to promoting the migration, of C6 cells. Dex was indicated to promote the expression of AQP1. Downregulation of AQP1, achieved using siRNAs, demonstrated the inhibition of cell proliferation, promotion of cell migration and suppression of invasion; therefore, Dex was indicated to serve a role in these effects in the C6 cells, via the upregulation of AQP1. This demonstrated that AQP1 could be utilized as a novel therapeutic target, with the aim of inhibiting the proliferation and metastasis of gliomas.

The melatonin-MT1 receptor axis modulates tumor growth in PTEN-mutated gliomas

More than 40% of glioma patients have tumors that harbor PTEN (phosphatase and tensin homologue deleted on chromosome ten) mutations; this disease is associated with poor therapeutic resistance and outcome. Such mutations are linked to increased cell survival and growth, decreased apoptosis, and drug resistance; thus, new therapeutic strategies focusing on inhibiting glioma tumorigenesis and progression are urgently needed. Melatonin, an indolamine produced and secreted predominantly by the pineal gland, mediates a variety of physiological functions and possesses antioxidant and antitumor properties. Here, we analyzed the relationship between PTEN and the inhibitory effect of melatonin in primary human glioma cells and cultured glioma cell lines. The results showed that melatonin can inhibit glioma cell growth both in culture and in vivo. This inhibition was associated with PTEN levels, which significantly correlated with the expression level of MT1 in patients. In fact, c-fos-mediated MT1 was shown to be a key modulator of the effect of melatonin on gliomas that harbor wild type PTEN. Taken together, these data suggest that melatonin-MT1 receptor complexes represent a potential target for the treatment of glioma.

Overexpression of FZD7 promotes glioma cell proliferation by upregulating TAZ

Gliomas are the most prevalent type of primary brain tumors in adults, accounting for more than 40% of neoplasm in the central nervous system. Frizzled-7 (FZD7) is a seven-pass trans-membrane Wnt receptor that plays a critical role in the development of various tumors. In this study, we detected high-level FZD7 expression in glioma and its overexpression was associated with advanced tumor stage. In vitro functional assays showed that forced overexpression of FZD7 promoted proliferation of gliomas cells, whereas knockdown of endogenous FZD7 significantly suppressed proliferation ability of these cells. In a xenograft assay, FZD7 was also found to promote the growth of glioma cells. We further found that FZD7 could activate transcriptional coactivator with PDZ-binding motif (TAZ), and TAZ was required for FZD7 to promote cell proliferation in glioma. Furthermore, the univariate analysis of survival shows that glioma patients with high FZD7 expression have a shorter survival. In conclusion, our findings demonstrate that FZD7 may promote glioma cell proliferation via upregulation of TAZ.

Metabolomics profiling in plasma samples from glioma patients correlates with tumor phenotypes

Background

Tumor-based molecular biomarkers have redefined in the classification gliomas. However, the association of systemic metabolomics with glioma phenotype has not been explored yet.

Methods

In this study, we conducted two-step (discovery and validation) metabolomic profiling in plasma samples from 87 glioma patients. The metabolomics data were tested for correlation with glioma grade (high vs low), glioblastoma (GBM) versus malignant gliomas, and IDH mutation status.

Results

Five metabolites, namely uracil, arginine, lactate, cystamine, and ornithine, significantly differed between high- and low-grade glioma patients in both the discovery and validation cohorts. When the discovery and validation cohorts were combined, we identified 29 significant metabolites with 18 remaining significant after adjusting for multiple comparisons. Those 18 significant metabolites separated high- from low-grade glioma patients with 91.1% accuracy. In the pathway analysis, a total of 18 significantly metabolic pathways were identified. Similarly, we identified 2 and 6 metabolites that significantly differed between GBM and non-GBM, and IDH mutation positive and negative patients after multiple comparison adjusting. Those 6 significant metabolites separated IDH1 mutation positive from negative glioma patients with 94.4% accuracy. Three pathways were identified to be associated with IDH mutation status. Within arginine and proline metabolism, levels of intermediate metabolites in creatine pathway were all significantly lower in IDH mutation positive than in negative patients, suggesting an increased activity of creatine pathway in IDH mutation positive tumors.

Conclusion

Our findings identified metabolites and metabolic pathways that differentiated tumor phenotypes. These may be useful as host biomarker candidates to further help glioma molecular classification.

Brain cancer genomics and epigenomics

Classically, brain cancers have been graded and diagnosed based on histology and risk stratified by clinical criteria. Recent advances in genomics and epigenomics have ushered in an era of defining cancers based on molecular criteria. These advances have increased our precision of identifying oncogenic driving events and, most importantly, increased our precision at predicting clinical outcome. For the first time in its history, the 2016 revision of the WHO Classification of Tumors of the Central Nervous System included molecular features as tumor classification criteria. Brain tumors can develop in the context of genetic cancer predisposition syndromes, such as Li-Fraumeni or Gorlin syndrome, but by far most commonly arise through the acquisition of somatic mutations and chromosome changes in the malignant cells. By taking a survey across this cancer landscape, certain themes emerge as being common events to drive cancer: DNA damage repair, genomic instability, mechanistic target of rapamycin pathway, sonic hedgehog pathway, hypoxia, and epigenetic dysfunction. Understanding these mechanisms is of paramount importance for improving targeted therapies, and for identifying the right patients for those therapies.

EMP-induced BBB-disruption enhances drug delivery to glioma and increases treatment efficacy in rats

Chemotherapy on gliomas is not satisfactorily efficient because the presence of blood-brain barriers (BBB) leads to inadequate exposure of tumor cells to administered drugs. In order to facilitate chemotherapeutics to penetrate BBB and increase the treatment efficacy of gliomas, electromagnetic pulse (EMP) was applied and the 1-(2-Chlorethyl)-cyclohexyl-nitrosourea (CCNU) lomustine concentration in tumor tissue, tumor size, tumor apoptosis, and side effects were measured in glioma-bearing rat model. The results showed that EMP exposure could enhance the delivery of CCNU to tumor tissue, facilitate tumor apoptosis, and inhibit tumor growth without obvious side effects. The data indicated that EMP-induced BBB disruption could enhance delivery of CCNU to glioblastoma multiforme and increase treatment efficacy in glioma-bearing rats. Bioelectromagnetics. 39:60-67, 2018. © 2017 Wiley Periodicals, Inc.

Efficacy and prognosis of surgery combined with 125I seed implantation in treatment of recurrent glioma

This study evaluated the efficacy of surgery combined with ¹²⁵I seed implantation in the treatment of recurrent glioma, and analyzed prognosis-influencing factors. A total of 66 patients with recurrent gliomas in Yidu Central Hospital of Weifang were enrolled in the study from April, 2011 to March, 2014. Patients were randomly divided into a control and an observation group, with 33 patients in each group. Patients in the control group were treated with surgery alone, and those in the observation group received surgery combined with ¹²⁵I seed implantation. Short-term curative effects in the two groups were compared using evaluation criteria for solid tumors. The comparison included the postoperative adverse reactions, the life quality (using the Karnofsky Performance Status or KPS), the survival time and prognostic factors (using the Kaplan-Meier survival, log-rank test and Cox regression analyses). Our results showed the objective response and disease control rates in the observation group were significantly higher than those in the control group (P<0.05). While no significant differences in postoperative adverse reactions were found between the two groups (P>0.05). The KPS score in the observation group was significantly higher than that in the control group at different time points after surgery (P<0.05). The survival rate and overall survival time of those in the observation group were significantly higher than those of the patients in the control group (P<0.05). The univariate analysis showed that preoperative KPS score, tumor pathological grade and degree of tumor resection were adverse factors influencing the prognosis of the patients (P<0.05). Also, multivariate Cox regression showed that preoperative KPS score, tumor pathological grade, and degree of tumor resection were independent risk factors of prognosis. Based on our findings, surgery combined with ¹²⁵I seed implantation can improve the survival rate of patients with recurrent glioma and prolong their survival time. Tumor pathological grade, degree of tumor resection and KPS score are the most important factors influencing the prognosis.

MicroRNA-675 promotes glioma cell proliferation and motility by negatively regulating retinoblastoma 1

Previous studies indicated that microRNA (miR)-675 and its precursor lncRNA H19 were both overexpressed in glioma tissues, and H19 might play an oncogenic role. To investigate the involvement of miR-675 in gliomas and its underlying mechanisms, we here collected candidate target genes of miR-675-5p from miRTarBase (http://mirtarbase.mbc.nctu.edu.tw/, Release 6.0), which contains the experimentally validated microRNA-target interactions. Then, regulatory effects of miR-675 on its target genes were validated using clinical samples and glioma cell lines. Involvement of the miR-675-target axis deregulation in cell proliferation, migration and invasion of glioma was demonstrated by both gain- and loss-of-function experiments. As a result, retinoblastoma 1 (RB1) was identified as a candidate target gene of miR-675-5p. Expression levels of miR-675-5p in glioma tissues and cells were negatively correlated with RB1 expression at both mRNA and protein levels. Importantly, deregulation of the miR-675-5p-RB1 axis was significantly associated with advanced World Health Organization (WHO) grade and low Karnofsky performance score (KPS) score of glioma patients. Luciferase reporter assay verified that RB1 was a direct target gene of miR-675 in glioma cells. Functionally, miR-675 promoted glioma cell proliferation, migration and invasion. Notably, simulation of RB1 antagonized the effects induced by miR-675 up-regulation in glioma cells. In conclusion, our data suggest that miR-675 may be a key negative regulator of RB1 and the imbalance of the miR-675-RB1 axis may be clinically associated with aggressive progression of glioma patients. In addition, miR-675 may act as an oncogenic miRNA in glioma cells via regulating its target gene RB1.

Nociceptin/orphanin FQ antagonizes lipopolysaccharide-stimulated proliferation, migration and inflammatory signaling in human glioblastoma U87 cells

Glioblastoma is among the most aggressive brain tumors and has an exceedingly poor prognosis. Recently, the importance of the tumor microenvironment in glioblastoma cell growth and progression has been emphasized. Toll-like receptor 4 (TLR4) recognizes bacterial lipopolysaccharide (LPS) and endogenous ligands originating from dying cells or the extracellular matrix involved in host defense and in inflammation. G-protein coupled receptors (GPCRs) have gained interest in anti-tumor drug discovery due to the role that they directly or indirectly play by transactivating other receptors, causing cell migration and proliferation. A proteomic analysis showed that the nociceptin receptor (NOPr) is among the GPCRs significantly expressed in glioblastoma cells, including U87 cells. We describe a novel role of the peptide nociceptin (N/OFQ), the endogenous ligand of the NOPr that counteracts cell migration, proliferation and increase in IL-1β mRNA elicited by LPS via TLR4 in U87 glioblastoma cells. Signaling pathways through which N/OFQ inhibits LPS-mediated cell migration and elevation of [Ca2+]i require β-arrestin 2 and are sensitive to TNFR-associated factor 6, c-Src and protein kinase C (PKC). LPS-induced cell proliferation and increase in IL-1β mRNA are counteracted by N/OFQ via β-arrestin 2, PKC and extracellular signal-regulated kinase 1/2; furthermore, the contributions of the transcription factors NF-kB and AP-1 were investigated. Independent of LPS, N/OFQ induces a significant increase in cell apoptosis. Contrary to what was observed in other cell models, a prolonged exposure to this endotoxin did not promote any tolerance of the cellular effects above described, including NOPr down-regulation while N/OFQ loses its inhibitory role.

Pilot Study of Whole Blood MicroRNAs as Potential Tools for Diffuse Low-Grade Gliomas Detection

Earlier diagnosis and longitudinal monitoring of diffuse low-grade gliomas (DLGG) increase overall survival by maximizing surgery efficacy and optimizing time for an adjuvant treatment when resection is incomplete. Presently, only imaging permits the non-invasive detection and monitoring of DLGG, but it lacks sensitivity. Measure of circulating microRNAs levels could represent a non-invasive alternative. We hypothesized that slow-growing DLGG induce overtime a systemic reaction impacting blood cells microRNA profiles, while the intact blood-brain barrier restricts the passage of tumor microRNAs into bloodstream. In 15 DLGG patients and 15 healthy controls, expression levels of 758 microRNAs were measured by the TaqMan OpenArray RT-qPCR platform, on preoperative whole blood, containing both cell-free and blood cells microRNAs. Normalized data were computed by a Student t test with a p value threshold allowing a 10% rate of false positive. Statistical analysis retained fifteen microRNAs, all overexpressed in patients. MiR-20a, miR-106a, miR-20b, and miR-93 belong to clusters genetically related. As miR-223 and miR-let7e, they target the transcription factor STAT3. MicroRNA expression levels were not correlated to preoperative tumor volume. A signature composed of miR-93, miR-590-3p, and miR-454 enabled to nearly perfectly separate patients from controls. Our study performed on a homogeneous cohort was designed accordingly to DLGG particularities and provided the first microRNAs signature proposal. Functional convergence on STAT3 and overexpression of miR-223, factors respectively involved in myeloid-derived suppressor cells and granulocytes, argued for a systemic peripheral response. Overexpressed microRNAs and tumor volume were uncorrelated, making a tumor origin elusive.

miR-142 inhibits the migration and invasion of glioma by targeting Rac1

Increasing evidence has shown that aberrant microRNAs (miRNAs) are implicated in tumorigenesis and tumor progression by regulating oncogenes or tumor suppressors. Dysregulation of miR-142 has been reported in multiple tumors. However, its clinical roles and underlying mechanism in glioma remain to be elucidated. In the present study, we found that the expression of miR-142 was significantly downregulated in both glioma tissues and cell lines by qRT-PCR. Clinical analysis revealed that decreased miR-142 was markedly associated with advanced World Health Organization (WHO) grade. Moreover, we disclosed that miR-142 was a novel independent prognostic marker in the prediction of the 5-year survival of glioma patients. The ectopic overexpression of miR-142 inhibited cell migration, invasion and invasion‑related gene expression. Notably, miR-142 modulated Rac1 by directly binding to its 3'-untranslated (3'-UTR) region, leading to the suppression of the expression of matrix metalloproteinases (MMPs). In glioma clinical samples, miR-142 was inversely correlated with Rac1 expression, and played positive roles in glioma migration and invasion. Alteration of Rac1 expression at least partially abolished the migration, invasion and MMP expression of miR-142 in glioma cells. In the present study, we identified Rac1 as a functional target of miR-142 in glioma. In conclusion, our data indicated that miR-142 inhibited the migration, invasion and MMP expression of glioma by targeting Rac1, and may represent a novel potential therapeutic target and prognostic marker for glioma.

Type 2 Diabetes Mellitus and Glioblastoma Multiforme-Assessing Risk and Survival: Results of a Large Retrospective Study and Systematic Review of the Literature

OBJECTIVE

Despite studies showing a positive correlation between type 2 diabetes mellitus (DM2), a modifiable risk factor, and various cancer types, the link remains controversial in the setting of glioblastoma multiforme (GBM). In this study, we assessed whether DM2 and DM2-associated factors were associated with a higher risk of developing GBM and also determined if DM2 affected the survival of patients with GBM.

METHODS

A cross-sectional case-control study of 1144 GBM cases diagnosed between 2000 and 2013 of which 969 patients matched for age and sex was performed to assess the association between DM2, hyperlipidemia, and obesity with the incidence of GBM. A longitudinal study of the patients with GBM was also performed to assess the association between the effect of DM2 and GBM survival.

RESULTS

No association was seen between DM2, hyperlipidemia, obesity, and GBM. DM2 was associated with poorer survival in univariate testing yet not in multivariate testing. Diabetic patients with GBM had good glycemic control. Older patients had poorer survival and overall survival improved over years of study.

CONCLUSIONS

DM2, hyperlipidemia, and obesity were not associated with increased risk of developing GBM, and DM2 itself does not seem to influence survival among these patients. This finding might be related to good glycemic control in this cohort. Survey of the literature consistently shows that hyperglycemia is associated with poorer survival. Our findings suggest that rather than the presence or absence of DM2, glycemic control seems to be more important in the survival of patients with GBM, which warrants future investigation.

PLD1 overexpression promotes invasion and migration and function as a risk factor for Chinese glioma patients

Glioma is a lethal disease with few effective therapeutic options. Recently, insights into cancer biology had suggested that abnormal lipid metabolism was a risk factor for various human malignancies, including glioma. As a key enzyme implicated in lipid metabolism, PLD1 was overexpression in multiple human cancers, and it was stated to be responsible for aggressive phenotypes, such as angiogenesis and chemoresistance. However, there was still much to know about its expression and function in glioma. In the present study, we showed that PLD1 was overexpression in clinical samples of glioma. In addition, the correlation assay revealed that PLD1 overexpression was correlated with poor differentiation (p = 0.04), and it was responsible for a poor prognosis for the patients (p = 0.009). Furthermore, we showed in COX regression assay that PLD1 was a risk factor for glioma (p = 0.018, HR = 0.461, 95% CI = 0.243–0.887). Consistently, we found that PLD1 was overexpression in glioma cell lines, and it could facilitate the proliferation and migration. Taken together, our study suggested that PLD1 was pro-tumoral in glioma, and that further studies were urgently needed so as to define whether it was a novel therapeutic target for the disease.

Molecular Testing of Brain Tumor

The World Health Organization (WHO) classification of central nervous system (CNS) tumors was revised in 2016 with a basis on the integrated diagnosis of molecular genetics. We herein provide the guidelines for using molecular genetic tests in routine pathological practice for an accurate diagnosis and appropriate management. While astrocytomas and IDH-mutant (secondary) glioblastomas are characterized by the mutational status of IDH, TP53, and ATRX, oligodendrogliomas have a 1p/19q codeletion and mutations in IDH, CIC, FUBP1, and the promoter region of telomerase reverse transcriptase (TERTp). IDH-wildtype (primary) glioblastomas typically lack mutations in IDH, but are characterized by copy number variations of EGFR, PTEN, CDKN2A/B, PDGFRA, and NF1 as well as mutations of TERTp. High-grade pediatric gliomas differ from those of adult gliomas, consisting of mutations in H3F3A, ATRX, and DAXX, but not in IDH genes. In contrast, well-circumscribed low-grade neuroepithelial tumors in children, such as pilocytic astrocytoma, pleomorphic xanthoastrocytoma, and ganglioglioma, often have mutations or activating rearrangements in the BRAF, FGFR1, and MYB genes. Other CNS tumors, such as ependymomas, neuronal and glioneuronal tumors, embryonal tumors, meningothelial, and other mesenchymal tumors have important genetic alterations, many of which are diagnostic, prognostic, and predictive markers and therapeutic targets. Therefore, the neuropathological evaluation of brain tumors is increasingly dependent on molecular genetic tests for proper classification, prediction of biological behavior and patient management. Identifying these gene abnormalities requires cost-effective and high-throughput testing, such as next-generation sequencing. Overall, this paper reviews the global guidelines and diagnostic algorithms for molecular genetic testing of brain tumors.

The interventional effect of new drugs combined with the Stupp protocol on glioblastoma: A network meta-analysis

OBJECTIVE

New therapeutic agents in combination with the standard Stupp protocol (a protocol about the temozolomide combined with radiotherapy treatment with glioblastoma was research by Stupp R in 2005) were assessed to evaluate whether they were superior to the Stupp protocol alone, to determine the optimum treatment regimen for patients with newly diagnosed glioblastoma.

PATIENTS AND METHODS

We implemented a search strategy to identify studies in the following databases: PubMed, Cochrane Library, EMBASE, CNKI, CBM, Wanfang, and VIP, and assessed the quality of extracted data from the trials included. Statistical software was used to perform network meta-analysis.

RESULTS

The use of novel therapeutic agents in combination with the Stupp protocol were all shown to be superior than the Stupp protocol alone for the treatment of newly diagnosed glioblastoma, ranked as follows: cilengitide 2000mg/5/week, bevacizumab in combination with irinotecan, nimotuzumab, bevacizumab, cilengitide 2000mg/2/week, cytokine-induced killer cell immunotherapy, and the Stupp protocol. In terms of serious adverse effects, the intervention group showed a 29% increase in the incidence of adverse events compared with the control group (patients treated only with Stupp protocol) with a statistically significant difference (RR=1.29; 95%CI 1.17-1.43; P<0.001). The most common adverse events were thrombocytopenia, lymphopenia, neutropenia, pneumonia, nausea, and vomiting, none of which were significantly different between the groups except for neutropenia, pneumonia, and embolism.

CONCLUSIONS

All intervention drugs evaluated in our study were superior to the Stupp protocol alone when used in combination with it. However, we could not conclusively confirm whether cilengitide 2000mg/5/week was the optimum regime, as only one trial using this protocol was included in our study.

Molecular markers in glioma

Gliomas are the most malignant and aggressive form of brain tumors, and account for the majority of brain cancer related deaths. Malignant gliomas, including glioblastoma are treated with radiation and temozolomide, with only a minor benefit in survival time. A number of advances have been made in understanding glioma biology, including the discovery of cancer stem cells, termed glioma stem cells (GSC). Some of these advances include the delineation of molecular heterogeneity both between tumors from different patients as well as within tumors from the same patient. Such research highlights the importance of identifying and validating molecular markers in glioma. This review, intended as a practical resource for both clinical and basic investigators, summarizes some of the more well-known molecular markers (MGMT, 1p/19q, IDH, EGFR, p53, PI3K, Rb, and RAF), discusses how they are identified, and what, if any, clinical relevance they may have, in addition to discussing some of the specific biology for these markers. Additionally, we discuss identification methods for studying putative GSC's (CD133, CD15, A2B5, nestin, ALDH1, proteasome activity, ABC transporters, and label-retention). While much research has been done on these markers, there is still a significant amount that we do not yet understand, which may account for some conflicting reports in the literature. Furthermore, it is unlikely that the investigator will be able to utilize one single marker to prospectively identify and isolate GSC from all, or possibly, any gliomas.

Optimized creation of glioblastoma patient derived xenografts for use in preclinical studies

Background

Glioblastoma multiforme (GBM) is the most common and lethal brain tumor in adults, highlighting the need for novel treatment strategies. Patient derived xenografts (PDX) represent a valuable tool to accomplish this task.

Methods

PDX were established by implanting GBM tissue subcutaneously. Engraftment success was compared between NMRI Foxn1^nu and NOD/SCID as well as between fresh and cryopreserved tissue. Established PDX were analyzed histologically and molecularly. Five PDX were experimentally treated with different drugs to assess their potential for preclinical drug testing.

Results

Establishment of PDX was attempted for 36 consecutive GBM cases with an overall success rate of 22.2% in NMRI Foxn1^nu mice. No difference was observed between fresh or cryopreserved (20–1057 days) tissue in direct comparison (n = 10 cases). Additionally, engraftment was better in NOD/SCID mice (38.8%) directly compared to NMRI Foxn1^nu mice (27.7%) (n = 18 cases). Molecular data and histology of the PDX compare well to the primary GBM. The experimental treatment revealed individual differences in the sensitivity towards several clinically relevant drugs.

Conclusions

The use of vitally frozen GBM tissue allows a more convenient workflow without efficiency loss. NOD/SCID mice appear to be better suited for initial engraftment of tumor tissue compared to NMRI Foxn1^nu mice.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1128-5) contains supplementary material, which is available to authorized users.

CCAAT/enhancer binding protein β negatively regulates progesterone receptor expression in human glioblastoma cells

Many progesterone (P4) actions are mediated by its intracellular receptor (PR), which has two isoforms (PR-A and PR-B) differentially transcribed from separate promoters of a single gene. In glioblastomas, the most frequent and aggressive brain tumors, PR-B is the predominant isoform. In an in silico analysis we showed putative CCAAT/Enhancer Binding Protein (C/EBP) binding sites at PR-B promoter. We evaluated the role of C/EBPβ in PR-B expression regulation in glioblastoma cell lines, which expressed different ratios of PR and C/EBPβ isoforms (LAP1, LAP2, and LIP). ChIP assays showed a significant basal binding of C/EBPβ, specific protein 1 (Sp1) and estrogen receptor alpha (ERα) to PR-B promoter. C/EBPβ knockdown increased PR-B expression and treatment with estradiol (E2) reduced C/EBPβ binding to the promoter and up-regulated PR-B expression. P4 induced genes were differently regulated when CEBP/β was silenced. These data show that C/EBPβ negatively regulates PR-B expression in glioblastoma cells.

Paxillin functions as an oncogene in human gliomas by promoting cell migration and invasion

Background

Paxillin is implicated in tumorigenesis, progression and aggressive phenotypes of various malignancies, highlighting its functions in cellular adhesion, migration and survival. However, the roles of paxillin in human gliomas remain unclear. The aim of this study was to evaluate the clinical implication of paxillin expression in patients with gliomas and its biological function in glioma cells.

Patients and methods

Expression levels of paxillin gene and protein, respectively, were detected by quantitative real-time reverse transcription polymerase chain reaction, Western blot and immunohistochemistry analyses in 120 pairs of glioma and matched nontumorous brain tissues. The associations between paxillin expression and various histopathological features of glioma patients were also statistically evaluated. Then, the functions of paxillin in cell migration and invasion of glioma cell lines were determined by transwell assays in vitro.

Results

The expression levels of both paxillin gene and protein in glioma tissues were markedly higher than those in matched nontumorous brain tissues. Notably, paxillin overexpression was significantly associated with the grade of malignancy (P<0.05). Moreover, the enforced expression of paxillin promoted the migration and invasion of glioma cells, while the loss of paxillin expression efficiently suppressed cell migration and invasion of glioma cell lines.

Conclusion

Our data suggest that paxillin may function as an oncogene and its overexpression may be closely correlated with tumor progression of human gliomas by modulating tumor cell motility, implying the potential of paxillin as a new therapeutic target for glioma intervention.

Dendritic cell immunotherapy versus bevacizumab plus irinotecan in recurrent malignant glioma patients: a survival gain analysis

Background

The bevacizumab and irinotecan protocol is considered a standard treatment regimen for recurrent malignant glioma. Recent advances in immunotherapy have hinted that vaccination with dendritic cells could become an alternative salvage therapy for the treatment of recurrent malignant glioma.

Methods

A search was performed on PubMed, Cochrane Library, Web of Science, ScienceDirect, and Embase in order to identify studies with patients receiving bevacizumab plus irinotecan or dendritic cell therapy for recurrent malignant gliomas. The data obtained from these studies were used to perform a systematic review and survival gain analysis.

Results

Fourteen clinical studies with patients receiving either bevacizumab plus irinotecan or dendritic cell vaccination were identified. Seven studies followed patients that received bevacizumab plus irinotecan (302 patients) and seven studies included patients that received dendritic cell immunotherapy (80 patients). For the patients who received bevacizumab plus irinotecan, the mean reported median overall survival was 7.5 (95% confidence interval [CI] 4.84–10.16) months. For the patients who received dendritic cell immunotherapy, the mean reported median overall survival was 17.9 (95% CI 11.34–24.46) months. For irinotecan + bevacizumab group, the mean survival gain was −0.02±2.00, while that for the dendritic cell immunotherapy group was −0.01±4.54.

Conclusion

For patients with recurrent malignant gliomas, dendritic cell immunotherapy treatment does not have a significantly different effect when compared with bevacizumab and irinotecan in terms of survival gain (P=0.535) and does not improve weighted survival gain (P=0.620).

The effects of CD147 on the cell proliferation, apoptosis, invasion, and angiogenesis in glioma

To analyze the effects of extracellular matrix metalloproteinase inducer (CD147) on glioma proliferation, apoptosis, invasion, and angiogenesis. Tissue samples were obtained from 101 glioma cases while normal brain tissues were obtained from 30 brain injury cases. Immunohistochemical assay was performed to detect the expressions of CD147, CD34, and VEGF in tissue samples. QRT-PCR was performed to detect the relative expression of CD147 mRNA in human glioma cell lines. CD147 siRNA was transfected into glioma cell line U251. Cell proliferation, apoptosis, invasion, and angiogenesis were tested by MTT, flow cytometry, Transwell assay, and vasculogenic mimicry assay, respectively. Expressions of relative proteins were analyzed with western blot. CD147 was positively expressed with the percentage of 0, 37.5, 44.8, 67.9, and 85.7 % in normal tissues and glioma tissues with WHO grades I-IV, respectively, and the scores of MVDand VEGF were associated with the expression of CD147. CD147 was significantly upregulated in the human glioma cell lines (P < 0.05). Downregulated the expression of CD147 suppressed cell proliferation, blocked cell cycle, induced apoptosis, inhibited cell invasion and angiogenesis in glioma cells in vitro. The expression of CD147 was significantly associated with WHO tumor grade and angiogenesis; silencing of CD147 contributed to inhibition of glioma proliferation, invasion, and angiogenesis. Our study provided firm evidence that CD 147 is a potential glioma target for anti-angiogenic therapies.

Mapping genetic factors in high-grade glioma patients

BACKGROUND

Tumor location, which serves as a prognostic factor for high-grade gliomas, may reflect the molecular and genetic phenotype of tumor initiate cells and thus predict tumor origin. Therefore, the purpose of this study was to combine radiographic atlases and tumor biomarkers through a voxel-based neuroimaging approach.

METHODS

Preoperative MRIs were collected from 65 newly diagnosed patients with histologically confirmed high-grades gliomas. These samples were analyzed for TP53 mutations and MMP-9.PTEN, MGMT, EGFR and IDH1 statuses using a statistical voxel-based lesion-symptom mapping (VLSM) method, which correlates the anatomical location of HGGs with their molecular profile.

RESULTS

VLSM analysis identified P53, Wild-type IDH and EGFR overexpression mutations in the white matter of the periventricular region in the left hemisphere, which can be predicted by a short overall survival from the time of diagnosis. The lack of MGMT promoter methylation deep in the right frontal lobe region indicates a poor prognosis.

CONCLUSIONS

Our study demonstrates that different molecular phenotypes are related to specific brain regions. In addition, the structural MRI and genetic profile-based analysis of brain regions associated with survival-associated factors could be used in planning glioma operations and clinical survival predictions.