Loss of GFAP expression in high-grade astrocytomas does not contribute to tumor development or progression

Glioblastoma Multiforme: The Latest Diagnostics and Treatment Techniques

BACKGROUND

Glioblastoma multiforme (GBM) is a WHO grade 4 glioma and the most common malignant primary brain tumour. Recently, there has been outstanding progress in the treatment of GBM. In addition to the newest form of GBM removal using fluorescence, three-dimensional (3D) imaging, tomoradiotherapy, moderate electro-hyperthermia, and adjuvant temozolomide (post-operative chemotherapy), new developments have been made in the fields of immunology, molecular biology, and virotherapy. An unusual and modern treatment has been created, especially for stage 4 GBM, using the latest therapeutic techniques, including immunotherapy and virotherapy. Modern oncological medicine is producing extraordinary and progressive therapeutic methods. Oncological therapy includes individual analysis of the properties of a tumour and targeted therapy using small-molecule inhibitors. Individualised medicine covers the entire patient (tumour and host) in the context of immunotherapy. An example is individualised multimodal immunotherapy (IMI), which relies on individual immunological tumour-host interactions. In addition, IMI is based on the concept of oncolytic virus-induced immunogenic tumour cell death.

SUMMARY

In this review, we outline current knowledge of the various available treatment options used in the therapy of GBM including both traditional therapeutic strategy and modern therapies, such as tomotherapy, electro-hyperthermia, and oncolytic virotherapy, which are promising treatment strategies with the potential to improve prognosis in patients with GBM.

KEY MESSAGES

This newest therapy, immunotherapy combined with virotherapy (oncolytic viruses and cancer vaccines), is displaying encouraging signs for combating GBM. Additionally, the latest 3D imaging is compared to conventional two-dimensional imaging.

A Rare Adult Primary Intracranial Sarcoma, DICER1-Mutant Identified by Epigenomic Profiling: A Case Report

Diagnoses of primary malignant mesenchymal brain tumors are a challenge for pathologists. Here, we report the case of a 52-year-old man with a primary brain tumor, histologically diagnosed as a high-grade glioma, not otherwise specified (NOS). The patient underwent two neurosurgeries in several months, followed by radiotherapy and chemotherapy. We re-examined the tumor samples by methylome profiling. Methylome analysis revealed an epi-signature typical of a primary intracranial sarcoma, DICER1-mutant, an extremely rare tumor. The diagnosis was confirmed by DNA sequencing that revealed a mutation in DICER1 exon 25. DICER1 mutations were not found in the patient's blood cells, thus excluding an inherited DICER1 syndrome. The methylome profile of the DICER1 mutant sarcoma was then compared with that of a high-grade glioma, a morphologically similar tumor type. We found that several relevant regions were differentially methylated. Taken together, we report the morphological, epigenetic, and genetic characterization of the sixth described case of an adult primary intracranial sarcoma, DICER1-mutant to-date. Furthermore, this case report underscores the importance of methylome analysis to refine primary brain tumor diagnosis and to avoid misdiagnosis among morphologically similar subtypes.

A Historical Review of Brain Drug Delivery

The history of brain drug delivery is reviewed beginning with the first demonstration, in 1914, that a drug for syphilis, salvarsan, did not enter the brain, due to the presence of a blood-brain barrier (BBB). Owing to restricted transport across the BBB, FDA-approved drugs for the CNS have been generally limited to lipid-soluble small molecules. Drugs that do not cross the BBB can be re-engineered for transport on endogenous BBB carrier-mediated transport and receptor-mediated transport systems, which were identified during the 1970s-1980s. By the 1990s, a multitude of brain drug delivery technologies emerged, including trans-cranial delivery, CSF delivery, BBB disruption, lipid carriers, prodrugs, stem cells, exosomes, nanoparticles, gene therapy, and biologics. The advantages and limitations of each of these brain drug delivery technologies are critically reviewed.

Single-Cell Molecular Characterization to Partition the Human Glioblastoma Tumor Microenvironment Genetic Background

Background: Glioblastoma (GB) is a devastating primary brain malignancy. The recurrence of GB is inevitable despite the standard treatment of surgery, chemotherapy, and radiation, and the median survival is limited to around 15 months. The barriers to treatment include the complex interactions among the different cellular components inhabiting the tumor microenvironment. The complex heterogeneous nature of GB cells is helped by the local inflammatory tumor microenvironment, which mostly induces tumor aggressiveness and drug resistance. Methods: By using fluorescent multiple labeling and a DEPArray cell separator, we recovered several single cells or groups of single cells from populations of different origins from IDH-WT GB samples. From each GB sample, we collected astrocytes-like (GFAP+), microglia-like (IBA1+), stem-like cells (CD133+), and endothelial-like cells (CD105+) and performed Copy Number Aberration (CNA) analysis with a low sequencing depth. The same tumors were subjected to a bulk CNA analysis. Results: The tumor partition in its single components allowed single-cell molecular subtyping which revealed new aspects of the GB altered genetic background. Conclusions: Nowadays, single-cell approaches are leading to a new understanding of GB physiology and disease. Moreover, single-cell CNAs resource will permit new insights into genome heterogeneity, mutational processes, and clonal evolution in malignant tissues.

Molecular features of glioblastomas in long-term survivors compared to short-term survivors—a matched-pair analysis

Background

Although glioblastoma (GB) is associated with a devastating prognosis, a small proportion of patients achieve long-term survival rates. We herein present a matched-pair analysis of molecular factors found in long- and short-term survivors (LTS, STS).

Methods

We performed a cross-institutional analysis of 262 patient records and matched a group of 91 LTS (≥ 3 years) with two groups of STS (STS-1, n = 91; STS-2, n = 80). Matching was performed according to age, Karnofsky Performance Status, initial therapy and adjuvant therapy. Molecular factors were compared between LTS (total of 91 patients) v. STS-1, and LTS (subgroup of 80 patients) v. STS-2. We included glial fibrillary acidic protein (GFAP), O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation, isocitrate dehydrogenase 1 (IDH-1); furthermore, the proliferation index was analyzed (Ki-67/MIB-1).

Results

IDH-1 and decreased Ki-67 were numerically associated with LTS but the difference was only significant compared to STS-1 (n.s. v. STS-2). LTS was associated with MGMT promoter hypermethylation (p = 0.013 and p = 0.022) and GFAP expression (p < 0.001 and p = 0.001). Positivity for both factors combined compared to negativity for one factor occurred more often in the LTS group (p = 0.002 and p = 0.006); negativity for both factors combined did not occur in the LTS group.

Conclusion

In this retrospective analysis, GFAP expression and MGMT promoter methylation were associated with LTS. Given the hypothesis-generating nature of our study, these observations should be confirmed in prospective clinical trials.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-022-01984-w.

GFAP Alternative Splicing and the Relevance for Disease – A Focus on Diffuse Gliomas

Glial fibrillary acidic protein (GFAP) is an intermediate filament protein that is characteristic for astrocytes and neural stem cells, and their malignant analogues in glioma. Since the discovery of the protein 50 years ago, multiple alternative splice variants of the GFAP gene have been discovered, leading to different GFAP isoforms. In this review, we will describe GFAP isoform expression from gene to protein to network, taking the canonical isoforms GFAPα and the main alternative variant GFAPδ as the starting point. We will discuss the relevance of studying GFAP and its isoforms in disease, with a specific focus on diffuse gliomas.

Rat Adipose-Derived Stromal Cells (ADSCs) Increases the Glioblastoma Growth and Decreases the Animal Survival

Many studies have shown that mesenchymal stromal cells (MSCs) and their secreted factors may modulate the biology of tumor cells. However, how these interactions happen in vivo remains unclear. In the present study, we investigated the effects of rat adipose-derived stromal cells (ADSCs) and their conditioned medium (ADSC-CM) in glioma tumor growth and malignancy in vivo. Our results showed that when we co-injected C6 cells plus ADSCs into the rat brains, the tumors generated were larger and the animals exhibited shorter survival, when compared with tumors of the animals that received only C6 cells or C6 cells pre-treated with ADSC-CM. We further showed that the animals that received C6 plus ADSC did not present enhanced expression of CD73 (a gene highly expressed in ADSCs), indicating that the tumor volume observed in these animals was not a mere consequence of the higher density of cells administered in this group. Finally, we showed that the animals that received C6 + ADSC presented tumors with larger necrosis areas and greater infiltration of immune cells. These results indicate that the immunoregulatory properties of ADSCs and its contribution to tumor stroma can support tumor growth leading to larger zones of necrosis, recruitment of immune cells, thus facilitating tumor progression. Our data provide new insights into the way by which ADSCs and tumor cells interact and highlight the importance of understanding the fate and roles of MSCs in tumor sites in vivo, as well as their intricate crosstalk with cancer cells.

Enhanced Anti-Tumor Activity in Mice with Temozolomide-Resistant Human Glioblastoma Cell Line-Derived Xenograft Using SN-38-Incorporated Polymeric Microparticle

Glioblastoma multiforme (GBM) has remained one of the most lethal and challenging cancers to treat. Previous studies have shown encouraging results when irinotecan was used in combination with temozolomide (TMZ) for treating GBM. However, irinotecan has a narrow therapeutic index: a slight dose increase in irinotecan can induce toxicities that outweigh its therapeutic benefits. SN-38 is the active metabolite of irinotecan that accounts for both its anti-tumor efficacy and toxicity. In our previous paper, we showed that SN-38 embedded into 50:50 biodegradable poly[(d,l)-lactide-co-glycolide] (PLGA) microparticles (SMPs) provides an efficient delivery and sustained release of SN-38 from SMPs in the brain tissues of rats. These properties of SMPs give them potential for therapeutic application due to their high efficacy and low toxicity. In this study, we tested the anti-tumor activity of SMP-based interstitial chemotherapy combined with TMZ using TMZ-resistant human glioblastoma cell line-derived xenograft models. Our data suggest that treatment in which SMPs are combined with TMZ reduces tumor growth and extends survival in mice bearing xenograft tumors derived from both TMZ-resistant and TMZ-sensitive human glioblastoma cell lines. Our findings demonstrate that combining SMPs with TMZ may have potential as a promising strategy for the treatment of GBM.

Changes in protein expression due to metformin treatment and hyperinsulinemia in a human endometrial cancer cell line

The incidence of endometrial cancer (EC) has increased over the past years and mainly affects women above the age of 45 years. Metabolic diseases such as obesity and type II diabetes mellitus as well as associated conditions like polycystic ovary syndrome (PCOS), insulin resistance and hyperinsulinemia lead to elevated levels of circulating estrogens. Increased estrogen concentrations, in turn, further trigger the proliferation of endometrial cells and thus promote EC development and progression, especially in the absence of progesterone as seen in postmenopausal women. Elevated blood glucose levels in diabetic patients further contribute to the risk of EC development. Metformin is an insulin-sensitizing biguanide drug, commonly used in the treatment of type II diabetes mellitus, especially in obese patients. Besides its effects on glucose metabolism, metformin displayed anti-cancer effects in various cancer types, including EC. Direct anti-cancer effects of metformin target signaling pathways that are involved in cellular growth and proliferation, e.g. the AKT/PKB/mTOR pathway. Further proteins and pathways have been suggested as potential targets, but the underlying mechanism of action of metformin's anti-cancer activity is still not completely understood. In the present study, the effects of metformin on protein expression were investigated in the human EC cell line HEC-1A using an affinity proteomic approach. Cells were treated with 0.5 mmol/L metformin over a period of 7 days and changes in the expression pattern of 1,300 different proteins were compared to the expression in untreated control cells as well as insulin-treated cells. Insulin treatment (100 ng/mL) was incorporated into the study in order to implement a model for insulin resistance and associated hyperinsulinemia, conditions that are often observed in obese and diabetic patients. Furthermore, the culture medium was supplemented with 10 nmol/L ß-estradiol (E2) during treatments to mimic increased estrogen levels, a common risk factor for EC development. Based on the most prominent and significant changes in expression, a set of 80 proteins was selected and subjected to a more detailed analysis. The data revealed that metformin and insulin targeted similar pathways in the present study and mostly acted on proteins related to proliferation, migration and tumor immune response. These pathways may be affected in a tumor-promoting as well as a tumor-suppressing way by either metformin treatment or insulin supplementation. The consequences for the cells resulting from the detected expression changes were discussed in detail for several proteins. The presented data helps identify potential targets affected by metformin treatment in EC and allows for a better understanding of the mechanism of action of the biguanide drug's anti-cancer activity. However, further investigations are necessary to confirm the observations and conclusions drawn from the presented data after metformin administration, especially for proteins that were regulated in a favorable way, i.e. AKT3, CCND2, CD63, CD81, GFAP, IL5, IL17A, IRF4, PI3, and VTCN1. Further proteins might be of interest, where metformin counteracted unfavorable effects that have been induced by hyperinsulinemia.

Intratumoral Distribution of Lactate and the Monocarboxylate Transporters 1 and 4 in Human Glioblastoma Multiforme and Their Relationships to Tumor Progression-Associated Markers

(1) Background: Metabolic reprogramming has been postulated to be one of the hallmarks of cancer, thus representing a promising therapeutic target also in glioblastoma multiforme (GBM). Hypoxic tumor cells produce lactate, and monocarboxylate transporters (MCTs) play an important role in its distribution; (2) Methods: We examined the distribution of lactate by multi voxel magnetic resonance spectroscopic imaging and ELISA in glioblastoma multiforme (GBM) patients. In addition, we investigated the expression and cellular localization of MCT1, MCT4, and of several markers connected to tumor progression by quantitative PCR and immunofluorescence double-staining in human GBM ex vivo tissues; (3) Results: The highest lactate concentration was found at the center of the vital parts of the tumor. Three main GBM groups could be distinguished according to their regional gene expression differences of the investigated genes. MCT1 and MCT4 were found on cells undergoing epithelial to mesenchymal transition and on tumor stem-like cells. GBM cells revealing an expression of cellular dormancy markers, showed positive staining for MCT4; (4) Conclusion: Our findings indicate the existence of individual differences in the regional distribution of MCT1 and MCT4 and suggest that both transporters have distinct connections to GBM progression processes, which could contribute to the drug resistance of MCT-inhibitors.

Injectable SN-38-embedded Polymeric Microparticles Promote Antitumor Efficacy against Malignant Glioma in an Animal Model

Malignant glioma (MG) is extremely aggressive and highly resistant to chemotherapeutic agents. Using electrospraying, the potent chemotherapeutic agent 7-ethyl-10-hydroxycamptothecia (SN-38) was embedded into 50:50 biodegradable poly[(d,l)-lactide-co-glycolide] (PLGA) microparticles (SMPs). The SMPs were stereotactically injected into the brain parenchyma of healthy rats and intratumorally injected into F98 glioma-bearing rats for estimating the pharmacodynamics and therapeutic efficacy. SN-38 was rapidly released after injection and its local (brain tissue) concentration remained much higher than that in the blood for more than 8 weeks. Glioma-bearing rats were divided into three groups—group A (n = 13; stereotactically injected pure PLGA microparticles), group B (n = 12; stereotactically injected Gliadel wafer and oral temozolomide), and group C (n = 13; stereotactic and intratumoral introduction of SMPs). The SMPs exhibited significant therapeutic efficacy, with prolonged survival, retarded tumor growth, and attenuated malignancy. The experimental results demonstrated that SMPs provide an effective and potential strategy for the treatment of MG.

Novel multi-drugs incorporating hybrid-structured nanofibers enhance alkylating agent activity in malignant gliomas

Background

Malignant gliomas (MGs) are highly chemotherapy-resistant. Temozolomide (TMZ) and carmustine (BiCNU) are alkylating agents clinically used for treating MGs. However, their effectiveness is restrained by overexpression of the DNA repair protein O⁶-methylguanine-DNA methyltransferase (MGMT) in tumors. O⁶-benzylguanine (O⁶-BG) is a nonreversible inhibitor of MGMT, it promotes the cytotoxicity of alkylating chemotherapy. The authors have developed a hybrid-structured nanofibrous membrane (HSNM) that sequentially delivers high concentrations of O⁶-BG, BiCNU, and TMZ in an attempt to provide an alternative to the current therapeutic options for MGs.

Methods

The HSNMs were implanted onto the cerebral surface of pathogen-free rats following surgical craniectomy, while the in vivo release behaviors of O⁶-BG, TMZ, and BiCNU from the HSNMs were explored. Subsequently, the HSNMs were surgically implanted onto the brain surface of two types of tumor-bearing rats. The survival rate, tumor volume, malignancy of tumor, and apoptotic cell death were evaluated and compared with other treatment regimens.

Results

The biodegradable HSNMs sequentially and sustainably delivered high concentrations of O⁶-BG, BiCNU, and TMZ for more than 14 weeks. The tumor-bearing rats treated with HSNMs demonstrated therapeutic advantages in terms of retarded and restricted tumor growth, prolonged survival time, and attenuated malignancy.

Conclusion

The results demonstrated that O⁶-BG potentiates the effects of interstitially transported BiCNU and TMZ. Therefore, O⁶-BG may be required for alkylating agents to offer maximum therapeutic benefits for the treatment of MGMT-expressing tumors. In addition, the HSNM-supported chemoprotective gene therapy enhanced chemotherapy tolerance and efficacy. It can, therefore, potentially provide an improved therapeutic alternative for MGs.

In vitro neurosphere formation correlates with poor survival in glioma

Sphere formation is an indicator of tumor aggressiveness independent of the tumor grade; however, its relation to progression-free survival (PFS) is less known. This study was designed to assess the neurosphere forming ability among low grade glioma (LGG) and high-grade glioma (HGG), its stem cell marker expression, and correlation to PFS. Tumor samples of 140 patients, including (LGG; n = 67) and (HGG; n = 73) were analyzed. We used sphere forming assay, immunofluorescence, and immunohistochemistry to characterize the tumors. Our study shows that, irrespective of the pathological sub type, both LGG and HGG formed neurospheres in vitro under conventional sphere forming conditions. However, the number of neurospheres formed from tumor tissues were significantly higher in HGG compared to LGG (P < 0.0001). Different grades of glioma were further characterized for the expression of stem cell marker proteins and lineage markers. When neurospheres were analyzed, CD133 positive cells were identified in addition to CD15 and nestin positive cells in both LGG and HGG. When these neurospheres were subjected to differentiation, cells positive for GFAP and β-tubulin III were observed. Expression of stem cell markers and β-tubulin III were prominent in HGG compared to LGG, whereas GFAP expression was higher in LGG than in HGG. Kaplan-Meier survival analysis demonstrated that neurosphere forming ability was significantly associated with shorter PFS (P < 0.05) in both LGG and HGG. Our results supports earlier studies that neurosphere formation may serve as a definitive indicator of stem cell population within the tumor and thus a better predictor of PFS than the tumor grades alone. © 2018 IUBMB Life, 71(1):244-253, 2019.

Effects of Chemically-Functionalized Single-Walled Carbon Nanotubes on the Morphology and Vitality of D54MG Human Glioblastoma Cells

The unique properties of single-walled carbon nanotubes (SWCNTs) have made them interesting candidates for applications in biomedicine. There are diverse chemical groups that can be attached to SWCNTs in order for these tiny tubes to gain various functionalities, for example, water solubility. Due to the availability of these “functionalization” approaches, SWCNTs are seen as agents for a potential anti-cancer therapy. In this context, we tested different chemically-functionalized forms of SWCNTs to determine which modifications make them better combatants against glioblastoma (astrocytoma grade IV), the deadliest brain cancer. We investigated the effects that two types of water soluble SWCNTs, functionalized with polyethylene glycol (SWCNT-PEG) or tetrahydrofurfuryl-terminated polyethylene glycol (SWCNT-PEG-THFF), have on the morphology and vitality, that is, cell adhesion, proliferation and death rate, of the D54MG human glioblastoma cells in culture. We found that SWCNT-PEG-THFF solute, when added to culture media, makes D54MG cells less round (measured as a significant decrease, by ~23%, in the form factor). This morphological change was induced by the PEG-THFF functional group, but not the SWCNT backbone itself. We also found that SWCNT-PEG-THFF solute reduces the proliferation rate of D54MG cells while increasing the rate of cell death. The functional groups PEG and PEG-THFF, on the other hand, reduce the cell death rate of D54MG human glioma cells. These data indicate that the process of functionalization of SWCNTs for potential use as glioma therapeutics may affect their biological effects.

Phenotypic and Expressional Heterogeneity in the Invasive Glioma Cells

BACKGROUND: Tumor cell invasion is a hallmark of glioblastoma (GBM) and a major contributing factor for treatment failure, tumor recurrence, and the poor prognosis of GBM. Despite this, our understanding of the molecular machinery that drives invasion is limited. METHODS: Time-lapse imaging of patient-derived GBM cell invasion in a 3D collagen gel matrix, analysis of both the cellular invasive phenotype and single cell invasion pattern with microarray expression profiling. RESULTS: GBM invasion was maintained in a simplified 3D-milieue. Invasion was promoted by the presence of the tumorsphere graft. In the absence of this, the directed migration of cells subsided. The strength of the pro-invasive repulsive signaling was specific for a given patient-derived culture. In the highly invasive GBM cultures, the majority of cells had a neural progenitor-like phenotype, while the less invasive cultures had a higher diversity in cellular phenotypes. Microarray expression analysis of the non-invasive cells from the tumor core displayed a higher GFAP expression and a signature of genes containing VEGFA, hypoxia and chemo-repulsive signals. Cells of the invasive front expressed higher levels of CTGF, TNFRSF12A and genes involved in cell survival, migration and cell cycle pathways. A mesenchymal gene signature was associated with increased invasion. CONCLUSION: The GBM tumorsphere core promoted invasion, and the invasive front was dominated by a phenotypically defined cell population expressing genes regulating traits found in aggressive cancers. The detected cellular heterogeneity and transcriptional differences between the highly invasive and core cells identifies potential targets for manipulation of GBM invasion.

Comparative In Vitro Study of 11C-Methionine and 11C-Deuterodeprenyl Uptake in Three Human Glioma Cell Lines

AIM

To compare the uptake of ¹¹C-deuterodeprenyl (¹¹C-DED) and ¹¹C-methionine (¹¹C-MET) in three human glioma cell lines and study the relationship with glial fibrillary acid protein (GFAP) and monoamine oxidase B (MAO B) expression. ¹¹C-DED is used in positron emission tomography imaging as a marker of astrocytosis in various central nervous system pathologies. It binds irreversibly to MAO B, a glial dimeric enzyme with increased activity in some neurological pathologies.

MATERIALS AND METHODS

Binding and internalization studies of ¹¹C-MET and ¹¹C-DED were performed in astrocytoma grade III, glioblastoma grade IV, and radio-resistant glioblastoma grade IV cells. Immunofluorescence was used.

RESULTS

¹¹C-MET specific activity bound to membrane was 9.0%-11.1% and that internalized was 88.9%-91.0%. ¹¹C-DED specific activity bound to membrane was 34.8%-58.0% and that internalized was 38.7%-65.2%. Immunocytochemistry revealed GFAP and MAO B expression.

CONCLUSIONS

The expression of MAO B measured by ¹¹C-DED uptake or immunocytochemistry was not significantly different in grade III or IV cells. The GFAP signal was higher for grade IV compared to grade III. ¹¹C-MET uptake was high in all the tumor cells. ¹¹C-DED is a dopamine analogue and the transport across cell membranes is expected to be mediated by DAT receptors present in astrocytes. Reactive astrocytes surround tumor lesions; so the authors suggest that the ¹¹C-DED uptake might be caused by the reactive astrocytosis and not by MAO B expression in tumor cells.

Virus vector-mediated genetic modification of brain tumor stromal cells after intravenous delivery

The malignant primary brain tumor, glioblastoma (GBM) is generally incurable. New approaches are desperately needed. Adeno-associated virus (AAV) vector-mediated delivery of anti-tumor transgenes is a promising strategy, however direct injection leads to focal transgene spread in tumor and rapid tumor division dilutes out the extra-chromosomal AAV genome, limiting duration of transgene expression. Intravenous (IV) injection gives widespread distribution of AAV in normal brain, however poor transgene expression in tumor, and high expression in non-target cells which may lead to ineffective therapy and high toxicity, respectively. Delivery of transgenes encoding secreted, anti-tumor proteins to tumor stromal cells may provide a more stable and localized reservoir of therapy as they are more differentiated than fast-dividing tumor cells. Reactive astrocytes and tumor-associated macrophage/microglia (TAMs) are stromal cells that comprise a large portion of the tumor mass and are associated with tumorigenesis. In mouse models of GBM, we used IV delivery of exosome-associated AAV vectors driving green fluorescent protein expression by specific promoters (NF-κB-responsive promoter and a truncated glial fibrillary acidic protein promoter), to obtain targeted transduction of TAMs and reactive astrocytes, respectively, while avoiding transgene expression in the periphery. We used our approach to express the potent, yet toxic anti-tumor cytokine, interferon beta, in tumor stroma of a mouse model of GBM, and achieved a modest, yet significant enhancement in survival compared to controls. Noninvasive genetic modification of tumor microenvironment represents a promising approach for therapy against cancers. Additionally, the vectors described here may facilitate basic research in the study of tumor stromal cells in situ.

Glioblastoma multiforme subterfuge as acute cerebral hemorrhage: A case report and literature review

Hemorrhagic related Glioblastoma multiforme (GBM) are rare and characterizes with severe clinical scuffle. The etiology of this presentation although not well known is believed to be multifactorial. We present a case as well as review on the pathogenesis of evolution of the hematoma into ring enhancing features of GBM on imaging studies. We present a case of 28 years old man who suddenly went into coma for 9 hours preceded with seizures that latest for 10 minutes. He had no focal neurological signs. CT-Scans images indicated acute cerebral hemorrhage near the frontal horn of the left ventricle with brain edema about the hemorrhagic lesion and MRI done a week later revealed a cerebral ring enhancing lesion. The lesion was partially resected during surgery and immunohistochemical staining confirmed GBM (WHO, grade 4). The diagnosis of intratumoral hemorrhage in GBM was very challenging at the initial stages but with time the hematoma evolved into ring enhancing images typical of GBM. It's not every intracranial hematoma that is of pure vascular origin.

Cellular prion protein controls stem cell-like properties of human glioblastoma tumor-initiating cells

Prion protein (PrP^C) is a cell surface glycoprotein whose misfolding is responsible for prion diseases. Although its physiological role is not completely defined, several lines of evidence propose that PrP^C is involved in self-renewal, pluripotency gene expression, proliferation and differentiation of neural stem cells. Moreover, PrP^C regulates different biological functions in human tumors, including glioblastoma (GBM). We analyzed the role of PrP^C in GBM cell pathogenicity focusing on tumor-initiating cells (TICs, or cancer stem cells, CSCs), the subpopulation responsible for development, progression and recurrence of most malignancies. Analyzing four GBM CSC-enriched cultures, we show that PrP^C expression is directly correlated with the proliferation rate of the cells. To better define its role in CSC biology, we knocked-down PrP^C expression in two of these GBM-derived CSC cultures by specific lentiviral-delivered shRNAs. We provide evidence that CSC proliferation rate, spherogenesis and in vivo tumorigenicity are significantly inhibited in PrP^C down-regulated cells. Moreover, PrP^C down-regulation caused loss of expression of the stemness and self-renewal markers (NANOG, Sox2) and the activation of differentiation pathways (i.e. increased GFAP expression). Our results suggest that PrP^C controls the stemness properties of human GBM CSCs and that its down-regulation induces the acquisition of a more differentiated and less oncogenic phenotype.

Advanced interstitial chemotherapy combined with targeted treatment of malignant glioma in rats by using drug-loaded nanofibrous membranes

Glioblastoma multiforme (GBM), the most prevalent and malignant form of a primary brain tumour, is resistant to chemotherapy. In this study, we concurrently loaded three chemotherapeutic agents [bis-chloroethylnitrosourea, irinotecan, and cisplatin; BIC] into 50:50 poly[(d,l)-lactide-co-glycolide] (PLGA) nanofibres and an antiangiogenic agent (combretastatin) into 75:25 PLGA nanofibres [BIC and combretastatin (BICC)/PLGA]. The BICC/PLGA nanofibrous membranes were surgically implanted onto the brain surfaces of healthy rats for conducting pharmacodynamic studies and onto C6 glioma-bearing rats for estimating the therapeutic efficacy.

The chemotherapeutic agents were rapidly released from the 50:50 PLGA nanofibres after implantation, followed by the release of combretastatin (approximately 2 weeks later) from the 75:25 PLGA nanofibres. All drug concentrations remained higher in brain tissues than in the blood for more than 8 weeks. The experimental results, including attenuated malignancy, retarded tumour growth, and prolonged survival in tumour-bearing rats, demonstrated the efficacy of the BICC/PLGA nanofibrous membranes. Furthermore, the efficacy of BIC/PLGA and BICC/PLGA nanofibrous membranes was compared. The BICC/PLGA nanofibrous membranes more efficiently retarded the tumour growth and attenuated the malignancy of C6 glioma-bearing rats. Moreover, the addition of combretastatin did not significantly change the drug release behaviour of the BIC/PLGA nanofibrous membranes. The present advanced and novel interstitial chemotherapy and targeted treatment provide a potential strategy and regimen for treating GBM.

A novel approach to glioma therapy using an oncolytic adenovirus with two specific promoters

Gliomas are the most common type of primary brain tumor in adults, where more than half of the cases are malignant, and the prognosis is poor. The early viral 1A (E1A) protein has been widely recognized to be essential for adenoviral replication and production of progeny virions in human cells, a process that is regulated by human telomerase reverse transcriptase. The p53 gene, as a tumor suppressor, regulates diverse cellular processes, including cell cycle arrest, cell autophagy, senescence and apoptosis. Dysfunction of the p53 pathways is common in malignant gliomas. Exogenous expression of p53 during adenovirus replication in human cancer cells may accelerate cell death and improve the release of early virus progeny. In the present study, a conditionally replicative adenovirus (CRAd) Ad-Tp-E1A-Gp-p53, which expressed functional p53 protein when replicating in cancer cells, was constructed. Next, the level of p53 expression in U251 cells was determined by western blot analysis, and the inhibitory effect of Ad-Tp-E1A-Gp-p53 on U251 cells was detected via an MTT assay. The results indicated that p53 expression was upregulated with an increase in the multiplicity of infection (MOI) of Ad-Tp-E1A-Gp-p53. Additionally, the inhibitory effects of Ad-Tp-E1A-Gp-p53 in different groups were significantly different (P<0.05), with the inhibition ratio of the experimental groups being higher, compared with the control group (P<0.05). Furthermore, the inhibition ratio increased with increases in the MOI of Ad-Tp-E1A-Gp-p53. Therefore, the expression of functional p53 and that of E1A may increase the potency of CRAd, and overexpression of p53 through CRAd is a promising approach to more effective treatments in a number of human cancer types.

GFAPδ/GFAPα ratio directs astrocytoma gene expression towards a more malignant profile

Astrocytomas are the most common malignant brain tumours and are to date incurable. It is unclear how astrocytomas progress into higher malignant grades. The intermediate filament cytoskeleton is emerging as an important regulator of malignancy in several tumours. The majority of the astrocytomas express the intermediate filament protein Glial Fibrillary Acidic Protein (GFAP). Several GFAP splice variants have been identified and the main variants expressed in human astrocytoma are the GFAPα and GFAPδ isoforms. Here we show a significant downregulation of GFAPα in grade IV astrocytoma compared to grade II and III, resulting in an increased GFAPδ/α ratio. Mimicking this increase in GFAPδ/α ratio in astrocytoma cell lines and comparing the subsequent transcriptomic changes with the changes in the patient tumours, we have identified a set of GFAPδ/α ratio-regulated high-malignant and low-malignant genes. These genes are involved in cell proliferation and protein phosphorylation, and their expression correlated with patient survival. We additionally show that changing the ratio of GFAPδ/α, by targeting GFAP expression, affected expression of high-malignant genes. Our data imply that regulating GFAP expression and splicing are novel therapeutic targets that need to be considered as a treatment for astrocytoma.

Pretreatment serum lactate level as a prognostic biomarker in patients undergoing supratentorial primary brain tumor resection

Introduction

Malignant primary brain tumors are one of the most aggressive cancers. Pretreatment serum nonneuronal biomarkers closely associated with postoperative outcomes are of high clinical relevance. The present study aimed to identify potential pretreatment serum biomarkers that may influence oncological outcomes in patients with primary brain tumors.

Methods

A total of 74 patients undergoing supratentorial primary brain tumor resection were enrolled. Before tumor resection, serum neuronal biomarkers, namely neuron-specific enolase (NSE), S100β, and glial fibrillary acidic protein (GFAP), and serum nonneuronal biomarkers, namely neutrophil gelatinase-associated lipocalin (NGAL), lactate dehydrogenase (LDH), and lactate, were measured and associated postoperative oncological outcomes, including brain tumor grading, progression-free survival (PFS), and overall survival (OS), were compared.

Results

Patients with high-grade brain tumors had significantly higher pretreatment serum lactate levels (p = 0.011). By contrast, other biomarkers were comparable between patients with high-grade and low-grade brain tumors. Receiver operating characteristic curve analysis of serum lactate levels yielded an area under the curve of 0.71 for differentiating between high-grade and low-grade brain tumors. Kaplan–Meier survival analysis revealed patients with high serum lactate levels (≧2.0 mmol/L) had shorter PFS and OS (p = 0.021 and p = 0.093, respectively). In a multiple regression model, only elevated serum lactate levels were associated with poor PFS and OS (p = 0.021 and p = 0.048, respectively).

Conclusions

An elevated pretreatment serum lactate level is a prognostic biomarker of high-grade primary brain tumors and is significantly associated with poor PFS in patients with supratentorial brain tumors undergoing tumor resection. By contrast, other serum biomarkers are not significantly associated with oncological outcomes.

Translational potential of astrocytes in brain disorders

Fundamentally, all brain disorders can be broadly defined as the homeostatic failure of this organ. As the brain is composed of many different cells types, including but not limited to neurons and glia, it is only logical that all the cell types/constituents could play a role in health and disease. Yet, for a long time the sole conceptualization of brain pathology was focused on the well-being of neurons. Here, we challenge this neuron-centric view and present neuroglia as a key element in neuropathology, a process that has a toll on astrocytes, which undergo complex morpho-functional changes that can in turn affect the course of the disorder. Such changes can be grossly identified as reactivity, atrophy with loss of function and pathological remodeling. We outline the pathogenic potential of astrocytes in variety of disorders, ranging from neurotrauma, infection, toxic damage, stroke, epilepsy, neurodevelopmental, neurodegenerative and psychiatric disorders, Alexander disease to neoplastic changes seen in gliomas. We hope that in near future we would witness glial-based translational medicine with generation of deliverables for the containment and cure of disorders. We point out that such as a task will require a holistic and multi-disciplinary approach that will take in consideration the concerted operation of all the cell types in the brain.

Concurrent Chemotherapy of Malignant Glioma in Rats by Using Multidrug-Loaded Biodegradable Nanofibrous Membranes

Glioblastoma multiforme has a poor prognosis and is highly chemoresistant. In this study, we implanted biodegradable 1,3-bis[2-chloroethyl]-1-nitroso-urea-, irinotecan-, and cisplatin-eluting poly[(d,l)-lactide-co-glycolide] (BIC/PLGA) and virgin nanofibrous membranes on the brain surface of C6 glioma-bearing rats in concurrent and virgin groups, respectively. The concentrations of all applied drugs were significantly higher in the brain than in the blood for more than 8 weeks in all studied rats. Tumor growth was more rapid in the vehicle-treated group, and tumor volumes were significantly higher in the vehicle-treated group. Moreover, the average survival time was significantly shorter in the vehicle-treated group (P = 0.026), and the BIC/PLGA nanofibrous membranes significantly reduced the risk of mortality (P < 0.001). Furthermore, the results suggested that the BIC/PLGA nanofibers reduced the malignancy of C6 glioma. The experimental findings indicate that the multianticancer drug (i.e., BIC)-eluting PLGA nanofibers are favorable candidates for treating malignant glioma.

Molecular Diagnostic and Prognostic Subtyping of Gliomas in Tunisian Population

It has become increasingly evident that morphologically similar gliomas may have distinct clinical phenotypes arising from diverse genetic signatures. To date, glial tumours from the Tunisian population have not been investigated. To address this, we correlated the clinico-pathology with molecular data of 110 gliomas by a combination of HM450K array, MLPA and TMA-IHC. PTEN loss and EGFR amplification were distributed in different glioma histological groups. However, 1p19q co-deletion and KIAA1549:BRAF fusion were, respectively, restricted to Oligodendroglioma and Pilocytic Astrocytoma. CDKN2A loss and EGFR overexpression were more common within high-grade gliomas. Furthermore, survival statistical correlations led us to identify Glioblastoma (GB) prognosis subtypes. In fact, significant lower overall survival (OS) was detected within GB that overexpressed EGFR and Cox2. In addition, IDH1R132H mutation seemed to provide a markedly survival advantage. Interestingly, the association of IDHR132H mutation and EGFR normal status, as well as the association of differentiation markers, defined GB subtypes with good prognosis. By contrast, poor survival GB subtypes were defined by the combination of PTEN loss with PDGFRa expression and/or EGFR amplification. Additionally, GB presenting p53-negative staining associated with CDKN2A loss or p21 positivity represented a subtype with short survival. Thus, distinct molecular subtypes with individualised prognosis were identified. Interestingly, we found a unique histone mutation in a poor survival young adult GB case. This tumour exceptionally associated the H3F3A G34R mutation and MYCN amplification as well as 1p36 loss and 10q loss. Furthermore, by exhibiting a remarkable methylation profile, it emphasised the oncogenic power of G34R mutation connecting gliomagenesis and chromatin regulation.

Prospective evaluation of serum glial fibrillary acidic protein (GFAP) as a diagnostic marker for glioblastoma

Glioblastoma (GBM) is the most common malignant primary brain tumor. Although clinical presentation and brain imaging might be suggestive, histopathological evaluation by means of a brain biopsy is routinely performed to establish the diagnosis. A serum marker indicative of GBM may simplify the diagnostic work-up of patients suspected to having a brain tumor. We prospectively examined 113 patients with newly diagnosed single supratentorial or infratentorial space-occupying brain lesions. Glial fibrillary acidic protein (GFAP) levels were determined from venous blood samples via a prototype ELISA assay prior to any invasive procedures. Serum levels of GFAP were correlated with histopathological findings and MRI parameters. GFAP values were significantly higher in GBM patients (n = 33) compared to all other tumors (p < 0.001). A GFAP serum concentration of ≥0.01 µg/L revealed a sensitivity of 85 % and a specificity of 70 % for differentiating GBM from other entities. By applying a GFAP cut-off point of 0.20 µg/L, specificity was maximized (99 %), but sensitivity dropped to 27 %. In GBM patients, serum GFAP values were significantly correlated with tumor volume. GBM patients with high GFAP levels showed more in vivo GFAP expression as well as more necrosis and perilesional edema compared to GBM patients having low or non-detectable GFAP levels. GFAP serum concentrations differentiated between patients with GBM and patients with cerebral mass lesions of other entities with a moderate diagnostic accuracy. Serum GFAP levels in GBM patients were positively correlated with tumor volume and histopathological tumor characteristics.

Withania somnifera Suppresses Tumor Growth of Intracranial Allograft of Glioma Cells

Gliomas are the most frequent type of primary brain tumor in adults. Their highly proliferative nature, complex cellular composition, and ability to escape therapies have confronted investigators for years, hindering the advancement toward an effective treatment. Agents that are safe and can be administered as dietary supplements have always remained priority to be most feasible for cancer therapy. Withania somnifera (ashwagandha) is an essential ingredient of Ayurvedic preparations and is known to eliminate cancer cells derived from a variety of peripheral tissues. Although our previous studies have addressed the in vitro anti-proliferative and differentiation-inducing properties of ashwagandha on neuronal cell lines, in vivo studies validating the same are lacking. While exploring the mechanism of its action in vitro, we observed that the ashwagandha water extract (ASH-WEX) induced the G2/M phase blockade and caused the activation of multiple pro-apoptotic pathways, leading to suppression of cyclin D1, bcl-xl, and p-Akt, and reduced the expression of polysialylated form of neural cell adhesion molecule (PSA-NCAM) as well as the activity of matrix metalloproteinases. ASH-WEX reduced the intracranial tumor volumes in vivo and suppressed the tumor-promoting proteins p-nuclear factor kappa B (NF-κB), p-Akt, vascular endothelial growth factor (VEGF), heat shock protein 70 (HSP70), PSA-NCAM, and cyclin D1 in the rat model of orthotopic glioma allograft. Reduction in glial fibrillary acidic protein (GFAP) and upregulation of mortalin and neural cell adhesion molecule (NCAM) expression specifically in tumor-bearing tissue further indicated the anti-glioma efficacy of ASH-WEX in vivo. Combining this enhanced understanding of the molecular mechanisms of ASH-WEX in glioma with in vivo model system offers new opportunities to develop therapeutic strategy for safe, specific, and effective formulations for treating brain tumors.

Glial fibrillary acidic protein (GFAP) and the astrocyte intermediate filament system in diseases of the central nervous system

Glial fibrillary acidic protein (GFAP) is the hallmark intermediate filament (IF; also known as nanofilament) protein in astrocytes, a main type of glial cells in the central nervous system (CNS). Astrocytes have a range of control and homeostatic functions in health and disease. Astrocytes assume a reactive phenotype in acute CNS trauma, ischemia, and in neurodegenerative diseases. This coincides with an upregulation and rearrangement of the IFs, which form a highly complex system composed of GFAP (10 isoforms), vimentin, synemin, and nestin. We begin to unravel the function of the IF system of astrocytes and in this review we discuss its role as an important crisis-command center coordinating cell responses in situations connected to cellular stress, which is a central component of many neurological diseases.

Roles and potential clinical applications of intermediate filament proteins in brain tumors

Intermediate filament (IF) proteins are cytoplasmic and nuclear cytoskeletal proteins. Of the ~70 IF proteins, nearly 12 are found in the nervous system, where their expression is largely cell-type specific. Astrocytes express glial fibrillary acidic protein (GFAP), whereas different neuron types contain neurofilament proteins, α-internexin, or peripherin. These proteins are often downregulated in brain cancer. In addition, brain cancer cells may also contain vimentin, nestin, and synemin, which are the IF proteins found in neural progenitor cells. In different brain tumor types, the expression of nestin, vimentin, and α-internexin appears to correlate with the clinical outcome. Experimental investigations have also demonstrated that IF proteins have distinct roles in specific brain tumor cell behaviors: nestin, for instance, is important for the proliferation of glioma cells, whereas synemin also affect their mobility. The mechanisms responsible for these effects involve the interaction of IF proteins with specific signaling pathways. Synemin, for instance, positively regulates glioma cell proliferation by antagonizing protein phosphatase 2A. Further evidence for the potential of IF proteins as therapeutic targets derives from animal models showing the influence of IF proteins on tumor growth. Nestin downregulation, for instance, dramatically reduced intracerebral glioma growth. Selective targeted therapies of IFs to date primarily include gene therapy approaches using nestin or GFAP gene promoters to drive transgene expression into glioma cells. Although attempts to identify small molecules specifically antagonizing IF proteins have been unsuccessful to date, it is anticipated that the identification of such compounds will be instrumental in expanding therapeutic approaches for brain tumors.

Glioblastoma multiforme - an overview

Glioblastoma multiforme is a central nervous system tumor of grade IV histological malignancy according to the WHO classification. Over 90% of diagnosed glioblastomas multiforme cases are primary gliomas, arising from normal glial cells through multistep oncogenesis. The remaining 10% are secondary gliomas originating from tumors of lower grade. These tumors expand distinctly more slowly. Although genetic alterations and deregulations of molecular pathways leading to both primary and secondary glioblastomas formation differ, morphologically they do not reveal any significant differences. Glioblastoma is a neoplasm that occurs spontaneously, although familial gliomas have also been noted. Caucasians, especially those living in industrial areas, have a higher incidence of glioblastoma. Cases of glioblastoma in infants and children are also reported. The participation of sex hormones and viruses in its oncogenesis was also suggested. Progression of glioblastoma multiforme is associated with deregulation of checkpoint G1/S of a cell cycle and occurrence of multiple genetic abnormalities of tumor cells. Metastases of glioblastoma multiforme are rarely described. Treatment of glioblastoma multiforme includes tumor resection, as well as radiotherapy and chemotherapy. Drugs inhibiting integrin signaling pathways and immunotherapy are also employed. Treatment modalities and prognosis depend on the tumor localization, degree of its malignancy, genetic profile, proliferation activity, patient's age and the Karnofsky performance scale score. Although the biology of glioblastoma multiforme has recently been widely investigated, the studies summarizing the knowledge of its development and treatment are still not sufficient in terms of comprehensive brain tumor analysis.

Chemically functionalized single-walled carbon nanotube films modulate the morpho-functional and proliferative characteristics of astrocytes

We used single-walled carbon nanotube (CNT) films to modulate the morpho-functional and proliferative characteristics of astrocytes. When plated on the CNT films of various thicknesses, astrocytes grow bigger and rounder in shape with a decrease in the immunoreactivity of glial fibrillary acidic protein along with an increase in their proliferation, changes associated with the dedifferentiation of astrocytes in culture. Thus, CNT films, as a coating material for electrodes used in brain machine interface, could reduce astrogliosis around the site of implantation.

Clinical significance and gene expression study of human hepatic stellate cells in HBV related-hepatocellular carcinoma

BACKGROUND

Peritumoral activated hepatic stellate cells (HSCs) are versatile myofibroblast-like cells closely related with hepatocellular carcinoma (HCC) progression. So far, comprehensive comparison of gene expression of human HSCs during hepatocarcinogenesis is scanty. Therefore, we identified the phenotypic and genomic characteristics of peritumoral HSCs to explore the valuable information on the prognosis and therapeutic targets of HBV related HCC.

METHODS

A tissue microarray containing 224 HBV related HCC patients was used to evaluate the expression of phenotype markers of HSCs including α-SMA, glial fibrillary acidic protein (GFAP), desmin, vinculin and vimentin. HSCs and cancer associated myofibroblasts (CAMFs) were isolated from normal, peritumoral human livers and cancer tissues, respectively. Flow cytometry and gene microarray analysis were performed to evaluate the phenotypic changes and gene expression in HCC, respectively.

RESULTS

Peritumoral α-SMA positive HSCs showed the prognostic value in time to recurrence (TTR) and overall survival (OS) of HCC patients, especially in early recurrence and AFP-normal HCC patients. Expression of GFAP positive HSCs cell lines LX-2 was significantly decreased after stimulation with tumor conditioned medium. Compared with quiescent HSCs, peritumoral HSCs and intratumoral CAMFs expressed considerable up- and down-regulated genes associated with biological process, cellular component, molecular function and signaling pathways involved in fibrogenesis, inflammation and progress of cancer.

CONCLUSIONS

Peritumoral activated HSCs displayed prognostic value in HBV related-HCC, and their genomic characteristics could present rational biomarkers for HCC risk and promising therapeutic targets.

Patterns of neural differentiation in melanomas

Background

Melanomas, highly malignant tumors arise from the melanocytes which originate as multipotent neural crest cells during neural tube genesis. The purpose of this study is to assess the pattern of neural differentiation in relation to angiogenesis in VGP melanomas using the tumor as a three dimensional system.

Methods

Tumor-vascular complexes [TVC] are formed at the tumor-stroma interphase, by tumor cells ensheathing angiogenic vessels to proliferate into a mantle of 5 to 6 layers [L1 to L5] forming a perivascular mantle zone [PMZ]. The pattern of neural differentiation is assessed by immunopositivity for HMB45, GFAP, NFP and synaptophysin has been compared in: [a] the general tumor [b] tumor-vascular complexes and [c] perimantle zone [PC] on serial frozen and paraffin sections. Statistical Analysis: ANOVA: Kruskal-Wallis One Way Analysis of Variance; All Pairwise Multiple Comparison Procedures [Tukey Test].

Results

The cells abutting on the basement membrane acquire GFAP positivity and extend processes. New layers of tumor cells show a transition between L2 to L3 followed by NFP and Syn positivity in L4&L5. The level of GFAP+vity in L1&L2 directly proportionate to the percentage of NFP/Syn+vity in L4&L5, on comparing pigmented PMZ with poorly pigmented PMZ. Tumor cells in the perimantle zone show high NFP [65%] and Syn [35.4%] positivity with very low GFAP [6.9%] correlating with the positivity in the outer layers.

Discussion

From this study it is seen that melanoma cells revert to the embryonic pattern of differentiation, with radial glial like cells [GFAP+ve] which further differentiate into neuronal positive cells [NFP&Syn+ve] during angiogenic tumor-vascular interaction, as seen during neurogenesis, to populate the tumor substance.

Radiation-induced astrogliosis and blood-brain barrier damage can be abrogated using anti-TNF treatment

PURPOSE

In this article, we investigate the role of tumor necrosis factor-alpha (TNF) in the initiation of acute damage to the blood-brain barrier (BBB) and brain tissue following radiotherapy (RT) for CNS tumors.

METHODS AND MATERIALS

Intravital microscopy and a closed cranial window technique were used to measure quantitatively BBB permeability to FITC-dextran 4.4-kDa molecules, leukocyte adhesion (Rhodamine-6G) and vessel diameters before and after 20-Gy cranial radiation with and without treatment with anti-TNF. Immunohistochemistry was used to quantify astrogliosis post-RT and immunofluorescence was used to visualize protein expression of TNF and ICAM-1 post-RT. Recombinant TNF (rTNF) was used to elucidate the role of TNF in leukocyte adhesion and vessel diameter.

RESULTS

Mice treated with anti-TNF showed significantly lower permeability and leukocyte adhesion at 24 and 48 h post-RT vs. RT-only animals. We observed a significant decrease in arteriole diameters at 48 h post-RT that was inhibited in TNF-treated animals. We also saw a significant increase in activated astrocytes following RT that was significantly lower in the anti-TNF-treated group. In addition, immunofluorescence showed protein expression of TNF and ICAM-1 in the cerebral cortex that was inhibited with anti-TNF treatment. Finally, administration of rTNF induced a decrease in arteriole diameter and a significant increase in leukocyte adhesion in venules and arterioles.

CONCLUSIONS

TNF plays a significant role in acute changes in BBB permeability, leukocyte adhesion, arteriole diameter, and astrocyte activation following cranial radiation. Treatment with anti-TNF protects the brain's microvascular network from the acute damage following RT.

Characterization of cells recovered from the xenotransplanted NG97 human-derived glioma cell line subcultured in a long-term in vitro

BACKGROUND

In order to elucidate tumoral progression and drug resistance, cultured cell lines are valuable tools applied on tumor related assays provided they are well established and characterized. Our laboratory settled the NG97 cell line derived from a human astrocytoma grade III, which started to develop and express important phenotypical characteristics of an astrocytoma grade IV after injection in the flank of nude mice. Astrocytomas are extremely aggressive malignancies of the Central Nervous System (CNS) and account for 46% of all primary malignant brain tumors. Progression to worse prognosis occurs in 85% of the cases possibly due to changes in cell tumor microenvironment and through biological pathways that are still unclear.

METHODS

This work focused on characterizing the NG97 cell line specifically after being recovered from the xenotransplant, who maintained their undifferentiated characteristics along the following 60th passages in vitro. These cells were subcultivated to evaluate the possible contribution of these undifferentiated characteristics to the malignant progression phenotype. These characteristics were the expression of molecules involved in the processes of migration, dedifferentiation and chromosomal instability.

RESULTS

Results showed that NG97(ht) had an decrease in doubling time through sub cultivation, which was characterized by a converse modulation between the expression of glial fibrillary acidic protein (GFAP) and vimentin. In addition, beta1 integrins were present in intermediate levels while alpha5 integrins had a high expression profile as well as fibronectin and laminin. Cytogenetic analysis of NG97(ht) revealed several chromosomal abnormalities, 89% of the cells showed to be hyperdiploid and the modal number was assigned to be 63. Several acrocentric chromosomes were visualized and at least 30 figures were attributed to be murine. These findings suggest a possible fusion between the original NG97 cells with stromal murine cells in the xenotransplant.

CONCLUSION

In this study the NG97(ht) cells were characterized to embryonic recovery patterns of intermediate filaments, adhesion molecules expression, chromosomal imbalances and murine chromosomes. In the latter case, these presumably chromosomes were originated as fusions between murine stroma cells and NG97 cell lineage in the xenotransplant. Our results emphasize important queries about astrocytomas tumor progression.

Brain tumor stem cells: bringing order to the chaos of brain cancer

Brain tumors are generally incurable cancers. Work from a number of laboratories strongly suggests that they are organized as a hierarchy based on a subset of cancer cells that have stem-cell properties. These cells have now been shown to be resistant to conventional therapy and responsive to differentiation therapy. New in vitro and in vivo models for interrogating brain tumor cells in stem-cell conditions have been developed that provide important new opportunities for elucidating the key pathways responsible for driving the proliferation of these cells. Continued application of the principles of stem-cell biology to the study of brain cancers is likely to continue to bring further important insight into these aggressive cancers, bringing new treatments and understanding of the origins.

Brain tumour stem cells: the undercurrents of human brain cancer and their relationship to neural stem cells

Conceptual and technical advances in neural stem cell biology are being applied to the study of human brain tumours. These studies suggest that human brain tumours are organized as a hierarchy and are maintained by a small number of tumour cells that have stem cell properties. Most of the bulk population of human brain tumours comprise cells that have lost the ability to initiate and maintain tumour growth. Although the cell of origin for human brain tumours is uncertain, recent evidence points towards the brain's known proliferative zones. The identification of brain tumour stem cells has important implications for understanding brain tumour biology and these cells may be critical cellular targets for curative therapy.

Identification and characterization of GFAPkappa, a novel glial fibrillary acidic protein isoform

Glial fibrillary acidic protein (GFAP) is the principal component of the intermediary filaments in mature astrocytes of the central nervous system (CNS). The protein consists of three domains: the head, the coiled-coil, and the tail. Here, we describe the isolation of an evolutionary conserved novel GFAP isoform, GFAPkappa, produced by alternative splicing and polyadenylation of the 3'-region of the human GFAP pre-mRNA. As a consequence, the resulting human GFAPkappa protein harbors a nonconserved C-terminal tail sequence distinct from the tails of GFAPalpha, the predominant GFAP isoform, and GFAPepsilon, an isoform which also results from alternative splicing. The head and coiled-coil rod domains are identical between the three GFAP isoforms. Interestingly, GFAPkappa is incapable of forming homomeric filaments, and increasing GFAPkappa expression levels causes a collapse of intermediate filaments formed by GFAPalpha. In searching for a biological relevance of GFAPkappa, we noticed that mRNA expression levels of GFAPalpha, GFAPepsilon, and GFAPkappa are gradually increased during development of the embryonic pig brain. However, whereas the GFAPalpha/GFAPepsilon ratio is constant, the GFAPkappa/GFAPepsilon ratio decreases during brain development. Furthermore, in glioblastoma tumors, an increased GFAPkappa/GFAPepsilon ratio is detected. Our results suggest that the relative expression level of the GFAPkappa isoform could modulate the properties of GFAP intermediate filaments and perhaps thereby influencing the motility of GFAP positive astrocytes and progenitor cells within the CNS.

Downregulation of GFAP, TSP-1, and p53 in human glioblastoma cell line, U373MG, by IE1 protein from human cytomegalovirus

Human cytomegalovirus (HCMV) is a member of the beta-herpesvirus family, which has tropism for glial cells. It was recently reported that HCMV might play important roles in the pathogenesis of malignant glioma. In this study, we investigated the effects of the HCMV IE1 protein on the gene expression profile in the human glioblastoma cell line, U373MG by employing cDNA microarray technology. Using DNA chips containing approximately 1,000 human cDNAs, RNA samples from U373MG cells stably expressing IE1 were compared with those from the control cells lacking IE1 cDNA. Fluorescence intensities of 13 genes were significantly decreased in IE1-expressing cells, while one gene was found to be upregulated. Among these 14 genes, we chose to work further on glial fibrillary acidic protein (GFAP), thrombospondin-1 (TSP-1), and p53, because of their previously known involvement in tumorigenesis. The mRNA levels of all these genes were found to be decreased in IE1-expressing glioblastoma cells by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR) as well as Northern blot analysis. The decreased expression of these genes was also observed at protein levels as measured by immunocytochemistry or fluorescence-activated cell sorting (FACS) analysis. Our data strongly suggested that HCMV IE1 could modulate the expression of cellular genes that might play important roles in the pathogenesis of glial tumors.

A bipotent neural progenitor cell line cloned from a cerebellum of an adultp53-deficient mouse generates both neurons and oligodendrocytes

Here we report developmental characteristics of a clonal cell line 2Y-3t established from a multifocal neoplasm that arose in a cerebellum of an adult p53-deficient mouse. The tumorigenicity of the line was not observed in soft agar assay or in nude mouse assay. In serum-containing medium, 2Y-3t cells were epithelial-like in morphology and were mitotic. When they were cultured in serum-free medium, the expressions of neural stem and/or progenitor cell markers were decreased. Concomitantly, the expressions of neuronal and oligodendrocyte markers were increased in concert with morphological differentiation, and DNA synthesis ceased. None of astrocyte markers were detected under these culture conditions. Double-labelling studies revealed that two cell populations coexisted, expressing neuronal or oligodendrocyte markers. Triiodothyronine (T3) increased the oligodendrocyte population when 2Y-3t cells were cultured in serum-free medium. Recloning of the line gave rise to three types of subclones. Sixteen subclones were capable of generating both neurons and oligodendrocytes, four subclones were capable of generating only neurons and one subclone was capable of generating only oligodendrocytes. Thus, 2Y-3t cells have characteristics of bipotent neural progenitor cells capable of generating both neurons and oligodendrocytes. In addition, the line expressed mRNA for Pax-2 and had GAD67-positive cells when cultured in serum-free medium. However, none of the mRNAs for Zic-1, Math1, zebrin or Calbindin-D28k were detected, suggesting that the 2Y-3t line might generate the GABAergic interneuron lineage of the mouse cerebellum.