Current and future strategies for the treatment of malignant brain tumors

Transient receptor potential vanilloid-1 (TRPV1) channels act as suppressors of the growth of glioma

The aim of this study was to investigate the expression and function of the transient receptor potential vanilloid 1 (TRPV1) in glioma. We found that the expression of TRPV1 mRNA and protein were upregulated in glioma compared with normal brain by qPCR and western blot analysis. In order to investigate the function of TRPV1 in glioma, short hairpin RNA (shRNA) and the inhibitor of TRPV1 were used. In vitro, the activation of TRPV1 induced cell apoptosis with decreased migration capability and inhibited proliferation, which was abolished upon TRPV1 pharmacological inhibition and silencing. Mechanistically, TRPV1 modulated glioma proliferation through the protein kinase B (Akt) signaling pathway. More importantly, in immunodeficient (NOD-SCID) mouse xenograft models, tumor size was significantly increased when TRPV1 expression was disrupted by a shRNA knockdown approach in vivo. Altogether, our findings indicate that TRPV1 negatively controls glioma cell proliferation in an Akt-dependent manner, which suggests that targeting TRPV1 may be a potential therapeutic strategy for glioma.

Combination of Caffeic Acid Phenethyl Ester and Crocin Realign Potential Molecular Markers in U87-MG Glioma Cells

Background

Glial tumors are the most common primary malignant central nervous system tumors. They are hard to treat, not only because of the deregulation in multiple pathways but also because they are not contained in a well-defined mass with clear borders. The use of a single therapeutic agent to target gliomas has yielded unsatisfactory results.

Objective

A combination of molecules targeting multiple pathways may prove to be a better alternative.

Methods

The effect of caffeic acid phenethyl ester and crocin on the proliferation and death of U87-MG cells over a concentration range was analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase assays. A colony formation assay was used to measure the effect of caffeic acid phenethyl ester and crocin on contact inhibition and anchorage independence ability of U87-MG cells. Furthermore, apoptosis in U87-MG cells was analyzed by propidium iodide assay. Real-time polymerase chain reaction and Western blotting were performed to determine the expression level of p53, epidermal growth factor receptor, and proliferating cell nuclear antigen.

Results

Caffeic acid phenethyl ester and crocin when used in combination present an anticancer potential for glioma. These molecules, in combination, inhibit proliferation and induce apoptosis in U87-MG glioma cells. Our results provide evidence that combination treatment realigns the expression paradigm of p53, epidermal growth factor receptor, and proliferating cell nuclear antigen in cotreated U87-MG cells.

Conclusions

The combination of caffeic acid phenethyl ester and crocin led to inhibition in glioma cell proliferation and might prove to be an effective adjunct to the therapies in vogue.

Quercetin and Glioma: Which signaling pathways are involved?

Abstract:

Gliomas are the most common brain tumors. These tumors commonly exhibit continuous growth without invading surrounding brain tissues. Dominant remedial approaches suffer limited therapy and survival rates. Although some progress has been made in conventional glioma treatments, these breakthroughs have not yet proven sufficient for treating this malignancy. The remedial options are limited given gliomas' aggressive metastasis and drug resistance. Quercetin, a flavonoid, is an anti-oxidative, anti-allergic, antiviral, anti-inflammatory, and anticancer compound. Multiple lines of evidence have shown that Quercetin has anti-tumor effects, documenting this natural compound exerts its pharmacological effects by targeting a variety of cellular and molecular processes, i.e., apoptosis, metastasis, and autophagy. Herein, we summarize various cellular and molecular pathways that are affected by Quercetin in gliomas.

Sulfonated Amphiphilic Poly(α)glutamate Amine—A Potential siRNA Nanocarrier for the Treatment of Both Chemo-Sensitive and Chemo-Resistant Glioblastoma Tumors

Development of chemo-resistance is a major challenge in glioblastoma (GB) treatment. This phenomenon is often driven by increased activation of genes associated with DNA repair, such as the alkyl-removing enzyme O⁶-methylguanine-DNA methyltransferase (MGMT) in combination with overexpression of canonical genes related to cell proliferation and tumor progression, such as Polo-like kinase 1 (Plk1). Hereby, we attempt to sensitize resistant GB cells using our established amphiphilic poly(α)glutamate (APA): small interfering RNA (siRNA) polyplexes, targeting Plk1. Furthermore, we improved brain-targeting by decorating our nanocarrier with sulfonate groups. Our sulfonated nanocarrier showed superior selectivity towards P-selectin (SELP), a transmembrane glycoprotein overexpressed in GB and angiogenic brain endothelial cells. Self-assembled polyplexes of sulfonated APA and siPlk1 internalized into GB cells and into our unique 3-dimensional (3D) GB spheroids inducing specific gene silencing. Moreover, our RNAi nanotherapy efficiently reduced the cell viability of both chemo-sensitive and chemo-resistant GB cells. Our developed sulfonated amphiphilic poly(α)glutamate nanocarrier has the potential to target siRNA to GB brain tumors. Our findings may strengthen the therapeutic applications of siRNA for chemo-resistant GB tumors, or as a combination therapy for chemo-sensitive GB tumors.

Aquaporin 4 and brain-related disorders: Insights into its apoptosis roles

Brain-related disorders are leading global health problems. Various internal and external factors are involved in the progression of brain-related disorders. Inflammatory pathways, oxidative stresses, apoptosis, and deregulations of various channels are critical players in brain-related disorder pathogenesis. Among these players, aquaporins (AQP) have critical roles in various physiological and pathological conditions. AQPs are water channel molecules that permit water to cross the hydrophobic lipid bilayers of cellular membranes. AQP4 is one of the important members of AQP family. AQPs are involved in controlling apoptosis pathways in brain-related disorders. In this regard, several reports have evaluated the pathological effects of AQP4 by targeting the apoptosis-related processes in brain-related disorders. Here, for the first time, we highlight the impact of AQP4 on apoptosis-related processes in brain-related disorders.

The Acidic Brain-Glycolytic Switch in the Microenvironment of Malignant Glioma

Malignant glioma represents a fatal disease with a poor prognosis and development of resistance mechanisms against conventional therapeutic approaches. The distinct tumor zones of this heterogeneous neoplasm develop their own microenvironment, in which subpopulations of cancer cells communicate. Adaptation to hypoxia in the center of the expanding tumor mass leads to the glycolytic and angiogenic switch, accompanied by upregulation of different glycolytic enzymes, transporters, and other metabolites. These processes render the tumor microenvironment more acidic, remodel the extracellular matrix, and create energy gradients for the metabolic communication between different cancer cells in distinct tumor zones. Escape mechanisms from hypoxia-induced cell death and energy deprivation are the result. The functional consequences are more aggressive and malignant behavior with enhanced proliferation and survival, migration and invasiveness, and the induction of angiogenesis. In this review, we go from the biochemical principles of aerobic and anaerobic glycolysis over the glycolytic switch, regulated by the key transcription factor hypoxia-inducible factor (HIF)-1α, to other important metabolic players like the monocarboxylate transporters (MCTs)1 and 4. We discuss the metabolic symbiosis model via lactate shuttling in the acidic tumor microenvironment and highlight the functional consequences of the glycolytic switch on glioma malignancy. Furthermore, we illustrate regulation by micro ribonucleic acids (miRNAs) and the connection between isocitrate dehydrogenase (IDH) mutation status and glycolytic metabolism. Finally, we give an outlook about the diagnostic and therapeutic implications of the glycolytic switch and the relation to tumor immunity in malignant glioma.

MCT4 Promotes Tumor Malignancy in F98 Glioma Cells

Monocarboxylate transporter 4 (MCT4, SLC16A3) is elevated under hypoxic conditions in many malignant tumors including gliomas. Moreover, MCT4 expression is associated with shorter overall survival. However, the functional consequences of MCT4 expression on the distinct hallmarks of cancer have not yet been explored at the cellular level. Here, we investigated the impact of MCT4 overexpression on proliferation, survival, cell death, migration, invasion, and angiogenesis in F98 glioma cells. Stable F98 glioma cell lines with MCT4 overexpression, normal expression, and knockdown were generated. Distinct hallmarks of cancer were examined using in silico analysis, various in vitro cell culture assays, and ex vivo organotypic rat brain slice culture model. Consistent with its function as lactate and proton exporter, MCT4 expression levels correlated inversely with extracellular pH and proportionally with extracellular lactate concentrations. Our results further indicate that MCT4 promotes proliferation and survival by altered cell cycle regulation and cell death mechanisms. Moreover, MCT4 overexpression enhances cell migration and invasiveness via reorganization of the actin cytoskeleton. Finally, MCT4 inhibition mitigates the induction of angiogenesis, suggesting that MCT4 also plays a crucial role in tumor-related angiogenesis. In summary, our data highlight MCT4/SLC16A3 as a key gene for distinct hallmarks of tumor malignancy in glioma cells.

A systematic review of multifocal and multicentric glioblastoma

Multiple glioblastoma multiforme (GBM) is classified as multifocal and multicentric GBM according to whether there is communication between the lesions. Multiple GBM is more genetically heterogeneous, aggressive and resistant to chemoradiotherapy than unifocal GBM, and has a worse prognosis. There is no international consensus on the treatment of multiple GBM. This review discusses some paradigms of multiple GBM and focuses on the heterogeneity spread pathway, imaging diagnosis, pathology, molecular characterization and prognosis of multifocal and multicentric GBM. Several promising therapeutic methods of multiple GBM are also recommended.

Role of Nanomedicine in Treatment of Brain Cancer

Background:

Drug delivery to cancerous brain is a challenging task as it is surrounded by an efficient protective barrier. The main hurdles for delivery of bioactive molecules to cancerous brain are blood brain barrier (BBB), the invasive nature of gliomas, drug resistance, and difficult brain interstitium transportation. Therefore, treatment of brain cancer with the available drug regimen is difficult and has shown little improvement in recent years.

Methods:

We searched about recent advancements in the use of nanomedicine for effective treatment of the brain cancer. We focused on the use of liposomes, nanoparticles, polymeric micelles, and dendrimers to improve brain cancer therapy.

Results:

Nanomedicines are well suited for the treatment of brain cancer owing to their highly acceptable biological, chemical, and physical properties. Smaller size of nanomedicines also enhances their anticancer potential and penetration into blood brain barrier (BBB).

Conclusion:

Recently, nanomedicine based approaches have been developed and investigated for effective treatment of brain cancer. Some of these have been translated into clinical practice, in order to attain therapeutic needs of gliomas. Future advancements in nanomedicines will likely produce significant changes in methods and practice of brain cancer therapy.

A cytoskeleton regulator AVIL drives tumorigenesis in glioblastoma

Glioblastoma is a deadly cancer, with no effective therapies. Better understanding and identification of selective targets are urgently needed. We found that advillin (AVIL) is overexpressed in all the glioblastomas we tested including glioblastoma stem/initiating cells, but hardly detectable in non-neoplastic astrocytes, neural stem cells or normal brain. Glioma patients with increased AVIL expression have a worse prognosis. Silencing AVIL nearly eradicated glioblastoma cells in culture, and dramatically inhibited in vivo xenografts in mice, but had no effect on normal control cells. Conversely, overexpressing AVIL promoted cell proliferation and migration, enabled fibroblasts to escape contact inhibition, and transformed immortalized astrocytes, supporting AVIL being a bona fide oncogene. We provide evidence that the tumorigenic effect of AVIL is partly mediated by FOXM1, which regulates LIN28B, whose expression also correlates with clinical prognosis. AVIL regulates the cytoskeleton through modulating F-actin, while mutants disrupting F-actin binding are defective in its tumorigenic capabilities.

Genes that modulate the cytoskeleton have been associated with increased cell proliferation and migration. Here, the authors show that AVIL, an actin regulatory protein, is overexpressed in glioblastomas and mediates oncogenic effects through regulation of FOXM1 stability and LIN28B expression.

Application of photodynamic therapy drugs for management of glioma

Human gliomas are one of the most prevalent and challenging-to-treat adult brain tumors, and thus result in high morbidity and mortality rates worldwide. Current research and treatments of gliomas include surgery associated with conventional chemotherapy, use of biologicals, radiotherapy, and medical device applications. The selected treatment options are often guided by the category and aggressiveness of this deadly disease and the patient’s conditions. However, the effectiveness of these approaches is still limited due to poor drug efficacy (including delivery to desired sites), undesirable side effects, and high costs associated with therapies. In addition, the degree of leakiness of the blood–brain barrier (BBB) that regulates trafficking of molecules in and out of the brain also modulates accumulation of adequate drug levels to tumor sites. Active research is being pursued to overcome these limitations to obtain a superior therapeutic index and enhanced patient survival. One area of development in this direction focuses on the localized application of photodynamic therapy (PDT) drugs to cure brain cancers. PDT molecules potentially utilize multiple pathways based on their ability to generate reactive oxygen species (ROS) upon photoactivation by a suitable light source. In this communication, we have attempted to provide a brief overview of PDT and cancer, photoactivation pathways, mechanism of tumor destruction, effect of PDT on tumor cell viability, immune activation, various research attempted by applying PDT in combination with novel strategies to treat glioma, role of BBB and clinical status of PDT therapy for glioma treatment.

Involvement of Heparan Sulfate and Heparanase in Neural Development and Pathogenesis of Brain Tumors

Brain tumors are aggressive and devastating diseases. The most common type of brain tumor, glioblastoma (GBM), is incurable and has one of the worst five-year survival rates of all human cancers. GBMs are invasive and infiltrate healthy brain tissue, which is one main reason they remain fatal despite resection, since cells that have already migrated away lead to rapid regrowth of the tumor. Curative therapy for medulloblastoma (MB), the most common pediatric brain tumor, has improved, but the outcome is still poor for many patients, and treatment causes long-term complications. Recent advances in the classification of pediatric brain tumors reveal distinct subgroups, allowing more targeted therapy for the most aggressive forms, and sparing children with less malignant tumors the side-effects of massive treatment. Heparan sulfate proteoglycans (HSPGs), main components of the neurogenic niche, interact specifically with a large number of physiologically important molecules and vital roles for HS biosynthesis and degradation in neural stem cell differentiation have been presented. HSPGs are composed of a core protein with attached highly charged, sulfated disaccharide chains. The major enzyme that degrades HS is heparanase (HPSE), an important regulator of extracellular matrix (ECM) remodeling which has been suggested to promote the growth and invasion of other types of tumors. This is of clinical interest because GBM are highly invasive and children with metastatic MB at the time of diagnosis exhibit a worse outcome. Here we review the involvement of HS and HPSE in development of the nervous system and some of its most malignant brain tumors, glioblastoma and medulloblastoma.

Surface modification of gold nanoparticles with neuron-targeted exosome for enhanced blood-brain barrier penetration

Gold nanoparticles (AuNPs) have been extensively used as nanomaterials for theranostic applications due to their multifunctional characteristics in therapeutics, imaging, and surface modification. In this study, the unique functionalities of exosome-derived membranes were combined with synthetic AuNPs for targeted delivery to brain cells. Here, we report the surface modification of AuNPs with brain-targeted exosomes derived from genetically engineered mammalian cells by using the mechanical method or extrusion to create these novel nanomaterials. The unique targeting properties of the AuNPs after fabrication with the brain-targeted exosomes was demonstrated by their binding to brain cells under laminar flow conditions as well as their enhanced transport across the blood brain barrier. In a further demonstration of their ability to target brain cells, in vivo bioluminescence imaging revealed that targeted-exosome coated AuNPs accumulated in the mouse brain after intravenous injection. The surface modification of synthetic AuNPs with the brain-targeted exosome demonstrated in this work represents a highly novel and effective strategy to provide efficient brain targeting and shows promise for the future in using modified AuNPs to penetrate the brain.

The role of the mitochondria and the endoplasmic reticulum contact sites in the development of the immune responses

Mitochondria and endoplasmic reticulum (ER) contact sites (MERCs) are dynamic modules enriched in subset of lipids and specialized proteins that determine their structure and functions. The MERCs regulate lipid transfer, autophagosome formation, mitochondrial fission, Ca2+ homeostasis and apoptosis. Since these functions are essential for cell biology, it is therefore not surprising that MERCs also play a critical role in organ physiology among which the immune system stands by its critical host defense function. This defense system must discriminate and tolerate host cells and beneficial commensal microorganisms while eliminating pathogenic ones in order to preserve normal homeostasis. To meet this goal, the immune system has two lines of defense. First, the fast acting but unspecific innate immune system relies on anatomical physical barriers and subsets of hematopoietically derived cells expressing germline-encoded receptors called pattern recognition receptors (PRR) recognizing conserved motifs on the pathogens. Second, the slower but very specific adaptive immune response is added to complement innate immunity. Adaptive immunity relies on another set of specialized cells, the lymphocytes, harboring receptors requiring somatic recombination to be expressed. Both innate and adaptive immune cells must be activated to phagocytose and process pathogens, migrate, proliferate, release soluble factors and destroy infected cells. Some of these functions are strongly dependent on lipid transfer, autophagosome formation, mitochondrial fission, and Ca2+ flux; this indicates that MERCs could regulate immunity.

In vitro and in vivo anti-cancer activity of dichloromethane fraction of Triticum aestivum sprouts

Triticum aestivum sprouts (TA) contain significant amounts of chlorophyll, minerals, enzymes, and other functional entities. Furthermore, TA extracts have been shown to possess anti-obesity, anti-diabetic and hepatoprotective effects and are believed to help blood flow, digestion, and general detoxification of the body. In this study, the mechanism underlying the anti-cancer effects of a dichloromethane fraction of TA (TDF) was investigated in vitro and in vivo. In vitro study was done by examining cancer cells growth, morphological changes, cell cycles, expressions of death receptors and apoptosis-linked proteins in wide range of human cancer cell lines. To investigate the effect of TDF in vivo, C57BL/6 mice were injected with B16 melanoma cells and orally administered TDF. TDF markedly inhibited cancer cell growth and induced cellular morphological alterations, cell cycle arrest and apoptosis, and enhanced the expressions of death receptors (DR)-4, 5, and 6 in cell lines. In addition, TDF regulated the expressions mitochondrial apoptosis-linked proteins and induced caspase-dependent cell death. It also significantly enhanced phosphorylation of ERK1/2 and JNK, but not p38, whereas inhibited the activation of NF-κB in cancer cells. In our mouse model, TDF significantly suppressed B16 melanoma growth, to an extent similar to cisplatin (reference control) and augmented immunomodulatory cytokines. In brief, this study presents the mechanism responsible for the anti-cancer effects of TDF in vitro and in vivo.

ER-mitochondria contacts control surface glycan expression and sensitivity to killer lymphocytes in glioma stem-like cells

Glioblastoma is a highly heterogeneous aggressive primary brain tumor, with the glioma stem-like cells (GSC) being more sensitive to cytotoxic lymphocyte-mediated killing than glioma differentiated cells (GDC). However, the mechanism behind this higher sensitivity is unclear. Here, we found that the mitochondrial morphology of GSCs modulates the ER-mitochondria contacts that regulate the surface expression of sialylated glycans and their recognition by cytotoxic T lymphocytes and natural killer cells. GSCs displayed diminished ER-mitochondria contacts compared to GDCs. Forced ER-mitochondria contacts in GSCs increased their cell surface expression of sialylated glycans and reduced their susceptibility to cytotoxic lymphocytes. Therefore, mitochondrial morphology and dynamism dictate the ER-mitochondria contacts in order to regulate the surface expression of certain glycans and thus play a role in GSC recognition and elimination by immune effector cells. Targeting the mitochondrial morphology, dynamism, and contacts with the ER could be an innovative strategy to deplete the cancer stem cell compartment to successfully treat glioblastoma.

Boron-containing delocalised lipophilic cations for the selective targeting of cancer cells

To limit the incidence of relapse, cancer treatments must not promote the emergence of drug resistance in tumour and cancer stem cells. Under the proviso that a therapeutic amount of boron is selectively delivered to cancer cells, Boron Neutron Capture Therapy (BNCT) may represent one approach that meets this requirement. To this end, we report the synthesis and pharmacology of several chemical entities, based on boron-rich carborane moieties that are functionalised with Delocalized Lipophilic Cations (DLCs), which selectively target the mitochondria of tumour cells. The treatment of tumour and cancer stem cells (CSCs) with such DLC-functionalized carboranes (DLC-carboranes) induces cell growth arrest that is both highly cancer-cell-selective and permanent. Experiments involving cultures of normal and cancer cells show that only normal cells exhibit recapitulation of their proliferation potential upon removal of the DLC-carborane treatment. At the molecular level, the pharmacological effect of DLC-carboranes is exerted through activation of the p53/p21 axis.

Quercetin-loaded freeze-dried nanomicelles: Improving absorption and anti-glioma efficiency in vitro and in vivo

To improve its poor aqueous solubility and stability, the potential chemopreventive agent quercetin was encapsulated in freeze-dried polymeric micelles by a thin film hydration and vacuum freeze-drying process before being used for glioma chemotherapy. The micelle characteristics, release profile, cellular uptake, intracellular drug concentration, transport across the blood-brain barrier, and antitumor efficiency in vivo were investigated. Results showed that the particle size of quercetin-loaded freeze-dried nanomicelles (QUE-FD-NMs) ranged from 20 to 80nm, with an efficiently sustained release profile. Increased intracellular uptake into Caco-2 cells with low cytotoxicity, efficient penetration of BBB, and powerful cytotoxicity on C6 glioma cells were observed. QUE-FD-NMs accumulated in tumor-bearing brain tissues and exhibited significant antitumor effects in vivo, which significantly benefited the survival of glioma-bearing mice. These findings suggest that freeze-drying micelles loaded with quercetin is a promising drug delivery method for glioma therapy.

Glioma Stemlike Cells Enhance the Killing of Glioma Differentiated Cells by Cytotoxic Lymphocytes

Glioblastoma multiforme, the most aggressive primary brain tumor, is maintained by a subpopulation of glioma cells with self-renewal properties that are able to recapitulate the entire tumor even after surgical resection or chemo-radiotherapy. This typifies the vast heterogeneity of this tumor with the two extremes represented on one end by the glioma stemlike cells (GSC) and on the other by the glioma differentiated cells (GDC). Interestingly, GSC are more sensitive to immune effector cells than the GDC counterpart. However, how GSC impact on the killing on the GDC and vice versa is not clear. Using a newly developed cytotoxicity assay allowing to simultaneously monitor cytotoxic lymphocytes-mediated killing of GSC and GDC, we found that although GSC were always better killed and that their presence enhanced the killing of GDC. In contrast, an excess of GDC had a mild protective effect on the killing of GSC, depending on the CTL type. Overall, our results suggest that during combination therapy, immunotherapy would be the most effective after prior treatment with conventional therapies.

In vitro and in vivo evaluation of functionalized chitosan-Pluronic micelles loaded with myricetin on glioblastoma cancer

This study aimed to develop a novel polymeric carrier based on chitosan-functionalized Pluronic P123/F68 micelles loaded with myricetin (MYR) to improve the therapeutic index of chemotherapy for glioblastoma cancer. Following characterization and assessment of the cellular uptake and antitumor effects of MYR-loaded micelles (MYR-MCs) in vitro, the acute toxicity, blood-brain barrier (BBB) translocation, brain uptake and biodistribution in vivo were assessed. The results demonstrated that MYR-MCs exhibited improved cellular uptake and antitumor activity compared to free MYR in vitro, with a significantly enhanced anticancer effect in vivo following efficient transport across the BBB. However, MYR-MCs did not affect the brain endothelial, barrier function, the liver, heart or kidneys. Furthermore, MYR-MCs altered the expression of apoptotic proteins, such as Bcl-2, BAD and BAX, in mice. In conclusion, MYR-MCs may be considered an effective and promising drug delivery system for glioblastoma treatment.

Therapeutic potential of cyclooxygenase-3 inhibitors in the management of glioblastoma

In this study we investigated the expression of COX-1, COX-2 and COX-3 mRNA in C6 glioblastoma and normal brain tissues and the effects of acetaminophen, indomethacin or metamizole treatments on the development of C6 glioblastoma in relation with COX inhibition. Glioblastoma cells were inoculated intracerebrally into frontal lobe of adult male Wistar albino rats. 10 days after inoculation, rats were treated with 150 mg/kg acetaminophen, 10 mg/kg indomethacin or 150 mg/kg metamizole. The tumor size was measured histologically and total RNA was isolated from tumor or normal brain tissue and mRNA levels of COX isoforms were determined by qRT-PCR. Our results showed the presence of COX-1, COX-2 and COX-3 expressions in both C6 glioblastoma and normal brain tissues. In tumor tissues COX-3 expression was significantly higher than normal brain tissue (p < 0.05) while there was no significant difference in COX-1 and COX-2 expressions. Acetaminophen and indomethacin decreased the tumor size by 71 and 43 % by inhibiting COX-3 mRNA expression around 87 and 91 % respectively. For the first time our study proposes a possible relationship between COX-3 mRNA expression and C6 glioblastoma development. We also suggested that the inhibition of COX-3 enzyme may be responsible for decrease in tumor size in part, the mechanism by which acetaminophen and indomethacin decreased rat C6 glioblastoma growth. However, the molecular events responsible for COX-3 effects on tumor development are still unresolved as these drugs exert their anti-cancer effect via both COX-3 dependent and independent mechanisms.

Regulation of connexin 43 and microRNA expression via β2-adrenoceptor signaling in 1321N1 astrocytoma cells

Connexin 43 (Cx43) is the main gap junction protein in astrocytes and exerts the same effects on growth inhibition in astrocytoma and glioma as microRNA-146a (miR-146a) in glioma. β2-adrenergic receptor (AR) signaling modulates Cx43 expression in myocytes via components downstream of protein kinase A (PKA) and exchange protein directly activated by cAMP (Epac). However, it remains to be elucidated how expression of Cx43 is modulated in astrocytes. In the present study, 1321N1 astrocytoma cells were treated with β2-AR signaling agents in order to evaluate the expression of Cx43 and miRNAs. RNA and protein were extracted from the cells for use in reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. The results revealed that clenbuterol increased miR-146a level and upregulated Cx43 expression via cAMP/PKA at the mRNA and protein level. Pre-inhibition of adenyl cyclase decreased expression of Cx43 and miR-146a. PKA activation and overexpression of miR-146a in A-1321N1 cells increased the expression of Cx43. β2-AR stimulation and 6Bnz, a PKA activator, suppressed oncomiRs miR-155 and miR-27a, while 8-(4-chlorophenylthio)-2'-O-methyladenosine-3',5'-cyclic monophosphate, an Epac activator, increased their levels. The current findings demonstrated that β2-AR signaling has growth inhibitory effects via modulation of the cAMP/PKA pathway in A-1321N1 cells through increasing the expression level of Cx43 and miR-146a as well as decreasing miR-155 and miR-27a levels. Thus, stimulation of the β2-AR and PKA signaling pathway may be a useful approach for astrocytoma therapy.

Loss of TRPV2 Homeostatic Control of Cell Proliferation Drives Tumor Progression

Herein we evaluate the involvement of the TRPV2 channel, belonging to the Transient Receptor Potential Vanilloid channel family (TRPVs), in development and progression of different tumor types. In normal cells, the activation of TRPV2 channels by growth factors, hormones, and endocannabinoids induces a translocation of the receptor from the endosomal compartment to the plasma membrane, which results in abrogation of cell proliferation and induction of cell death. Consequently, loss or inactivation of TRPV2 signaling (e.g., glioblastomas), induces unchecked proliferation, resistance to apoptotic signals and increased resistance to CD95-induced apoptotic cell death. On the other hand, in prostate cancer cells, Ca2+-dependent activation of TRPV2 induced by lysophospholipids increases the invasion of tumor cells. In addition, the progression of prostate cancer to the castration-resistant phenotype is characterized by de novo TRPV2 expression, with higher TRPV2 transcript levels in patients with metastatic cancer. Finally, TRPV2 functional expression in tumor cells can also depend on the presence of alternative splice variants of TRPV2 mRNA that act as dominant-negative mutant of wild-type TRPV2 channels, by inhibiting its trafficking and translocation to the plasma membrane. In conclusion, as TRP channels are altered in human cancers, and their blockage impair tumor progression, they appear to be a very promising targets for early diagnosis and chemotherapy.

Radiobiological framework for the evaluation of stereotactic radiosurgery plans for invasive brain tumours

This study presents a radiobiological formalism for the evaluation of the treatment plans with respect to the probability of controlling tumours treated with stereotactic radiosurgery accounting for possible infiltrations of malignant cells beyond the margins of the delineated target. Treatments plans devised for three anaplastic astrocytoma cases were assumed for this study representing cases with different difficulties for target coverage. Several scenarios were considered regarding the infiltration patterns. Tumour response was described in terms of tumour control probability (TCP) assuming a Poisson model taking into account the initial number of clonogenic cells and the cell survival. The results showed the strong impact of the pattern of infiltration of tumour clonogens outside the delineated target on the outcome of the treatment. The treatment plan has to take into account the existence of the possible microscopic disease around the visible lesion; otherwise the high gradients around the target effectively prevent the sterilisation of the microscopic spread leading to low probability of control, in spite of the high dose delivered to the target. From this perspective, the proposed framework offers a further criterion for the evaluation of stereotactic radiosurgery plans taking into account the possible infiltration of tumour cells around the visible target.

Surgical management of high-grade gliomas

High-grade gliomas, in particular anaplastic astrocytoma and glioblastoma multiforme, represent two of the most devastating forms of brain cancer. In spite of the poor prognosis, new treatments and emerging therapies are making an impact on this disease. This review discusses the role of the surgical management of high-grade gliomas and provides an overview of the currently available therapies which depend on surgical intervention. At the same time, cutting-edge clinical trials for patients with malignant brain tumors are reviewed to provide further insights into potential future therapies.

Gene therapy in endocrine tumors: a comprehensive overview

Effective treatment strategies that help tackle the complex problems associated with managing endocrine cancers are in great demand. Because of the shortcomings in current treatments and the problems associated with the treatment strategies used in the cure and/or management of endocrine cancers, considerable effort must be devoted to developing new and effective therapeutic strategies. Gene therapy represents an area of both basic and clinical research that can potentially be considered a therapeutic option in treating endocrine cancers. Therefore, we consider it timely to summarize the studies related to gene-therapy interventions that are available for treating endocrine cancers and to highlight the major limitations of and the recent progress made in these therapies. After systematically reviewing the literature, we provide a comprehensive overview of distinct studies conducted to evaluate gene-therapy approaches in various endocrine cancers. Some of these successful studies have been extended toward translational investigations. The emerging view is that an integrative approach is required to combat the pitfalls associated with gene-therapy studies, especially in endocrine cancers.

Whole brain radiation-induced cognitive impairment: pathophysiological mechanisms and therapeutic targets

Radiation therapy, the most commonly used for the treatment of brain tumors, has been shown to be of major significance in tu-mor control and survival rate of brain tumor patients. About 200,000 patients with brain tumor are treated with either partial large field or whole brain radiation every year in the United States. The use of radiation therapy for treatment of brain tumors, however, may lead to devastating functional deficits in brain several months to years after treatment. In particular, whole brain radiation therapy results in a significant reduction in learning and memory in brain tumor patients as long-term consequences of treatment. Although a number of in vitro and in vivo studies have demonstrated the pathogenesis of radiation-mediated brain injury, the cel-lular and molecular mechanisms by which radiation induces damage to normal tissue in brain remain largely unknown. Therefore, this review focuses on the pathophysiological mechanisms of whole brain radiation-induced cognitive impairment and the iden-tification of novel therapeutic targets. Specifically, we review the current knowledge about the effects of whole brain radiation on pro-oxidative and pro-inflammatory pathways, matrix metalloproteinases (MMPs)/tissue inhibitors of metalloproteinases (TIMPs) system and extracellular matrix (ECM), and physiological angiogenesis in brain. These studies may provide a foundation for defin-ing a new cellular and molecular basis related to the etiology of cognitive impairment that occurs among patients in response to whole brain radiation therapy. It may also lead to new opportunities for therapeutic interventions for brain tumor patients who are undergoing whole brain radiation therapy.

Endothelial differentiation of adipose tissue-derived mesenchymal stromal cells in glioma tumors: implications for cell-based therapy

Multipotent human adipose tissue mesenchymal stromal cells (hAMSCs) are promising therapy vehicles with tumor-homing capacity that can be easily modified to deliver cytotoxicity activating systems in the proximity of tumors. In a previous work, we observed that hAMSCs are very effective delivering cytotoxicity to glioma tumors. However, these results were difficult to reconcile with the relatively few hAMSCs surviving implantation. We use a bioluminescence imaging (BLI) platform to analyze the behavior of bioluminescent hAMSCs expressing HSV-tTK in a U87 glioma model and gain insight into the therapeutic mechanisms. Tumor-implanted hAMSCs express the endothelial marker PECAM1(CD31), integrate in tumor vessels and associate with CD133-expressing glioma stem cells (GSC). Inhibition of endothelial lineage differentiation in hAMSCs by Notch1 shRNA had no effect on their tumor homing and growth-promoting capacity but abolished the association of hAMSCs with tumor vessels and CD133+ tumor cells and significantly reduced their tumor-killing capacity. The current strategy allowed the study of tumor/stroma interactions, showed that tumor promotion and tumor-killing capacities of hAMSCs are based on different mechanisms. Our data strongly suggest that the therapeutic effectiveness of hAMSCs results from their association with special tumor vascular structures that also contain GSCs.

PEG2000-DPSE-coated quercetin nanoparticles remarkably enhanced anticancer effects through induced programed cell death on C6 glioma cells

In this study, PEGylated nanoparticles quercetin drug delivery vehicles were investigated as carriers for anticancer drugs induced programed cell death (PCD). PEG2000-DPSE-coated quercetin nanoparticles were prepared and tumor cell killing efficacy was studied on glioma C6 cells and assayed for cell survival, apoptosis, or necrosis. The levels of ROS production and mitochondrial membrane potential (ΔΨm) were determined. Western blot assayed p53, p-p53, cytochrome C, and caspase proteins expression were also studied. Results indicate that PEG2000-DPSE-QUE-NPS showed dose-dependent cytotoxicity to C6 glioma cells and enhanced ROS accumulation induced upregulation of p53 protein, which was accompanied with an increase in cytochrome c and caspase-3 protein levels. These results support the hypothesis that quercetin nanoparticles-coated PEG2000-DPSE remarkably enhanced anticancer effect of induced programed cell death on C6 glioma cells. Overall, PEG2000-DPSE-coated quercetin nanoparticles showed promising potential as a drug carrier for cancer therapy.

Kaurene diterpene induces apoptosis in U87 human malignant glioblastoma cells by suppression of anti-apoptotic signals and activation of cysteine proteases

Gliomas are the most common and malignant primary brain tumors in humans. Studies have shown that classes of kaurene diterpene have anti-tumor activity related to their ability to induce apoptosis. We investigated the response of the human glioblastoma cell line U87 to treatment with ent-kaur-16-en-19-oic acid (kaurenoic acid, KA). We analyzed cell survival and the induction of apoptosis using flow cytometry and annexin V staining. Additionally, the expression of anti-apoptotic (c-FLIP and miR-21) and apoptotic (Fas, caspase-3 and caspase-8) genes was analyzed by relative quantification (real-time PCR) of mRNA levels in U87 cells that were either untreated or treated with KA (30, 50, or 70 µM) for 24, 48, and 72 h. U87 cells treated with KA demonstrated reduced viability, and an increase in annexin V- and annexin V/PI-positive cells was observed. The percentage of apoptotic cells was 9% for control cells, 26% for cells submitted to 48 h of treatment with 50 µM KA, and 31% for cells submitted to 48 h of treatment with 70 µM KA. Similarly, in U87 cells treated with KA for 48 h, we observed an increase in the expression of apoptotic genes (caspase-8, -3) and a decrease in the expression of anti-apoptotic genes (miR-21 and c-FLIP). KA possesses several interesting properties and induces apoptosis through a unique mechanism. Further experiments will be necessary to determine if KA may be used as a lead compound for the development of new chemotherapeutic drugs for the treatment of primary brain tumors.

Engineered drug resistant γδ T cells kill glioblastoma cell lines during a chemotherapy challenge: a strategy for combining chemo- and immunotherapy

Classical approaches to immunotherapy that show promise in some malignancies have generally been disappointing when applied to high-grade brain tumors such as glioblastoma multiforme (GBM). We recently showed that ex vivo expanded/activated γδ T cells recognize NKG2D ligands expressed on malignant glioma and are cytotoxic to glioma cell lines and primary GBM explants. In addition, γδ T cells extend survival and slow tumor progression when administered to immunodeficient mice with intracranial human glioma xenografts. We now show that temozolomide (TMZ), a principal chemotherapeutic agent used to treat GBM, increases the expression of stress-associated NKG2D ligands on TMZ-resistant glioma cells, potentially rendering them vulnerable to γδ T cell recognition and lysis. TMZ is also highly toxic to γδ T cells, however, and to overcome this cytotoxic effect γδ T cells were genetically modified using a lentiviral vector encoding the DNA repair enzyme O(6)-alkylguanine DNA alkyltransferase (AGT) from the O(6)-methylguanine methyltransferase (MGMT) cDNA, which confers resistance to TMZ. Genetic modification of γδ T cells did not alter their phenotype or their cytotoxicity against GBM target cells. Importantly, gene modified γδ T cells showed greater cytotoxicity to two TMZ resistant GBM cell lines, U373(TMZ-R) and SNB-19(TMZ-R) cells, in the presence of TMZ than unmodified cells, suggesting that TMZ exposed more receptors for γδ T cell-targeted lysis. Therefore, TMZ resistant γδ T cells can be generated without impairing their anti-tumor functions in the presence of high concentrations of TMZ. These results provide a mechanistic basis for combining chemotherapy and γδ T cell-based drug resistant cellular immunotherapy to treat GBM.

Combination of paclitaxel thermal gel depot with temozolomide and radiotherapy significantly prolongs survival in an experimental rodent glioma model

OncoGel™ incorporates paclitaxel, a mitotic inhibitor, into ReGel™, a thermosensitive gel depot system to provide local delivery, enhance efficacy and limit systemic toxicity. In previous studies the alkylating agent temozolomide (TMZ) incorporated into a polymer, pCPP:SA, also for local delivery, and OncoGel were individually shown to increase efficacy in a rat glioma model. We investigated the effects of OncoGel with oral TMZ or locally delivered TMZ polymer, with and without radiotherapy (XRT) in rats with intracranial gliosarcoma. Eighty-nine animals were intracranially implanted with a 9L gliosarcoma tumor and divided into 12 groups that received various combinations of 4 treatment options; OncoGel 6.3 mg/ml (Day 0), 20 Gy XRT (Day 5), 50 % TMZ-pCPP:SA (Day 5), or oral TMZ (50 mg/kg, qd, Days 5-9). Animals were followed for survival for 120 days. Median survival for untreated controls, XRT alone or oral TMZ alone was 15, 19 and 28 days, respectively. OncoGel 6.3 or TMZ polymer alone extended median survival to 33 and 35 days, respectively (p = 0.0005; p < 0.0001, vs. untreated controls) with 50 % living greater than 120 days (LTS) in both groups. Oral TMZ/XRT extended median survival to 36 days (p = 0.0002), with no LTS. The group that received OncoGel and Oral TMZ did not reach median survival with 57 % LTS (p = 0.0002). All other combination groups [OncoGel/XRT], [TMZ polymer/XRT], [OncoGel/TMZ polymer], [OncoGel/TMZ polymer/XRT], and [OncoGel/oral TMZ/XRT] yielded greater than 50 % LTS (p < 0.0001 for each combination as compared to controls), therefore median survival was not reached. OncoGel/TMZ polymer and OncoGel/oral TMZ/XRT had 100 % LTS (p < 0.0001 and p = 0.0001 vs. oral TMZ/XRT, respectively). These results indicate that OncoGel given locally with oral or locally delivered TMZ and/or XRT significantly increased the number of LTS and improved median survival compared to oral TMZ and XRT given alone or in combination in a rodent intracranial gliosarcoma model.

Selection of DNA aptamers against glioblastoma cells with high affinity and specificity

Background

Glioblastoma is the most common and most lethal form of brain tumor in human. Unfortunately, there is still no effective therapy to this fatal disease and the median survival is generally less than one year from the time of diagnosis. Discovery of ligands that can bind specifically to this type of tumor cells will be of great significance to develop early molecular imaging, targeted delivery and guided surgery methods to battle this type of brain tumor.

Methodology/Principal Findings

We discovered two target-specific aptamers named GBM128 and GBM131 against cultured human glioblastoma cell line U118-MG after 30 rounds selection by a method called cell-based Systematic Evolution of Ligands by EXponential enrichment (cell-SELEX). These two aptamers have high affinity and specificity against target glioblastoma cells. They neither recognize normal astraglial cells, nor do they recognize other normal and cancer cell lines tested. Clinical tissues were also tested and the results showed that these two aptamers can bind to different clinical glioma tissues but not normal brain tissues. More importantly, binding affinity and selectivity of these two aptamers were retained in complicated biological environment.

Conclusion/Significance

The selected aptamers could be used to identify specific glioblastoma biomarkers. Methods of molecular imaging, targeted drug delivery, ligand guided surgery can be further developed based on these ligands for early detection, targeted therapy, and guided surgery of glioblastoma leading to effective treatment of glioblastoma.

Evaluation of the antiangiogenic effect of Kringle 1-5 in a rat glioma model

BACKGROUND

Kringle 1-5 (K1-5) is a potent antiangiogenesis factor for treating breast cancer and hepatocellular carcinoma. However, its use in treating brain tumors has not been studied.

OBJECTIVE

To evaluate whether K1-5 is effective at treating gliomas.

METHODS

The effects of K1-5 on cell morphology and cytotoxicity with or without lipopolysaccharide were tested in primary mixed neuronal-glial cultures. The antiglioma activity of K1-5 was evaluated by intra-arterial administration of K1-5 at 4 days after implantation of C6 glioma cells into the rat hippocampus. In 1 group of animals, tumor size, tumor vasculature, and tumor histology were evaluated on day 12. Animal survival was assessed in the other group.

RESULTS

In vitro studies showed that K1-5 did not induce cytotoxicity in neurons and glia. In vivo studies demonstrated that K1-5 reduced vessel length and vessel density and inhibited perivascular tumor invasion. In addition, K1-5 normalized vessel morphology, decreased expression of hypoxia-inducible factor-1α and vascular endothelial growth factor, decreased tumor hypoxia, and decreased pseudopalisading necrosis. The average tumor volume was smaller in the treated than in the untreated group. Furthermore, animals treated with K1-5 survived significantly longer.

CONCLUSION

Kringle 1-5 effectively reduces the growth of malignant gliomas in the rat. Although still far from translation in humans, K1-5 might be a possible future alternative treatment option for patients with gliomas.

Effects of quercetin nanoliposomes on C6 glioma cells through induction of type III programmed cell death

Background

Quercetin has been shown to induce apoptosis in a number of cancer cell lines, but a quercetin-loaded nanoliposomal formulation with enhanced antitumor activity in C6 glioma cells and its effect on cancer cell death has not been well studied. The aim of this study was to examine if quercetin-loaded liposomes (QUE-NL) has enhanced cytotoxic effects and if such effects involve type III programmed cell death in C6 glioma cells.

Methods

C6 glioma cells were treated with QUE-NL and assayed for cell survival, apoptosis, and necrosis. Levels of reactive oxygen species production and loss of mitochondrial membrane potential (ΔΨm) were also determined by flow cytometry assay to assess the effects of QUE-NL. ATP levels and lactate dehydrogenase activity were measured, and Western blotting was used to assay cytochrome C release and caspase expression.

Results

QUE-NL induced type III (necrotic) programmed cell death in C6 glioma cells in a dose-dependent and time-dependent manner. High concentrations of QUE-NL induced cell necrosis, which is distinct from apoptosis and autophagy, whereas liposomes administered alone induced neither significant apoptosis nor necrosis in C6 glioma cells. QUE-NL-induced ΔΨm loss and cytochrome C release had no effect on caspase activation, but decreased ATP levels and increased lactate dehydrogenase activity indicated that QUE-NL stimulated necrotic cell death.

Conclusion

C6 glioma cells treated with QUE-NL showed a cellular pattern associated with necrosis without apoptosis and was independent of caspase activity. Nonapoptotic cell death induced by high concentrations of QUE-NL for controlling caspase-independent type III programmed cell death may provide the basis for novel therapeutic approaches to overcome avoidance of apoptosis by malignant cells.

Zoledronic acid enhances Vδ2 T-lymphocyte antitumor response to human glioma cell lines

Glioblastoma multiforme (GBM), the most frequent and aggressive primary brain tumor in humans, responds modestly to treatment: most patients survive less than one year after diagnosis, despite both classical and innovative treatment approaches. A recent paper focused on γδ T-cell response in GBM patients, suggesting the application of an immunomodulating strategy based on γδ T-cells which is already in clinical trials for other tumors. Human Vγ2 T-cells recognize changes in the mevalonate metabolic pathway of transformed cells by activating cytotoxic response, and by cytokine and chemokine release. Interestingly, this activation may also be induced in vivo by drugs, such as zoledronic acid, that induce the accumulation of Vγ2 T-cell ligand Isopentenyl-pyrophosphate by blocking the farnesyl pyrophosphate synthase enzyme. The aim of our work is to confirm whether bisphosphonate treatment would make glioma cell lines more susceptible to lysis by in vitro expanded γδ T-cells, improving their antitumor activity. We expanded in vitro human Vγ2 T-cells by phosphoantigen stimulation and tested their activity against glioma cell lines. Co-culture with glioma cells induced Vγ2 T-cell differentiation in effector/memory cells, killing glioma cells by the release of perforin. Interestingly, glioma cells were directly affected by zoledronic acid; moreover, treatment increased their activating ability on Vγ2 T-cells, inducing an effective antitumor cytotoxic response. Taken together, our results show that aminobisphosphonate drugs may play a dual role against GBM, by directly affecting tumor cells, and by enhancing the antitumor response of Vγ2 T-cells. Our results confirm the practicability of this approach as a new immunotherapeutic strategy for GBM treatment.

Intracranial microcapsule drug delivery device for the treatment of an experimental gliosarcoma model

Controlled-release drug delivery systems are capable of treating debilitating diseases, including cancer. Brain cancer, in particular glioblastoma multiforme (GBM), is an extremely invasive cancer with a dismal prognosis. The use of drugs capable of crossing the blood-brain barrier has shown modest prolongation in patient survival, but not without unsatisfactory systemic, dose-limiting toxicity. Among the reasons for this improvement include a better understanding of the challenges of delivery of effective agents directly to the brain tumor site. The combination of carmustine delivered by biodegradable polyanhydride wafers (Gliadel(®)), with the systemic alkylating agent, temozolomide, allows much higher effective doses of the drug while minimizing the systemic toxicity. We have previously shown that locally delivering these two drugs leads to further improvement in survival in experimental models. We postulated that microcapsule devices capable of releasing temozolomide would increase the therapeutic capability of this approach. A biocompatible drug delivery microcapsule device for the intracranial delivery of temozolomide is described. Drug release profiles from these microcapsules can be modulated based on the physical chemistry of the drug and the dimensions of the release orifices in these devices. The drug released from the microcapsules in these experiments was the clinically utilized chemotherapeutic agent, temozolomide. In vitro studies were performed in order to test the function, reliability, and drug release kinetics of the devices. The efficacy of the temozolomide-filled microcapsules was tested in an intracranial experimental rodent gliosarcoma model. Immunohistochemical analysis of tissue for evidence of DNA strand breaks via terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed. The experimental release curves showed mass flow rates of 36 μg/h for single-orifice devices and an 88 μg/h mass flow rate for multiple-orifice devices loaded with temozolomide. In vivo efficacy results showed that localized intracranial delivery of temozolomide from microcapsule devices was capable of prolonging animal survival and may offer a novel form of treatment for brain tumors.

Expression of activin A and follistatin in glioblastoma and their effects on U87 in vitro

In some cancer cell lines, the gene encoding activin A (inhibin βA [INHBA]) is over-expressed and enhances cancer proliferation. Protein levels of activin A and follistatin were assessed in glioblastoma and normal brain tissues in this study, and the effect of activin A and follistatin treatment on the proliferation of U87 human glioblastoma cells in vitro was also studied. High levels of activin A were observed in glioblastomas compared with normal brain tissue. In contrast, follistatin levels were similar between the two tissues. [(3)H]Thymidine assay showed that activin A (3 - 30 ng/ml) produced a dose-dependent increase in DNA synthesis of U87 cells compared with controls. Flow cytometric analyses showed that activin A increased the proliferative index of U87 cells compared with controls. Activin A also induced up-regulation of p-SMAD2/3 in a dose-dependent manner. Treatment of U87 cells with follistatin blocked these activin A-induced effects. The disequilibrium between activin A and follistatin may play a role in the development of glioblastoma.

Morphological and flow cytometric analysis of cell infiltration in glioblastoma: a comparison of autopsy brain and neuroimaging

Even when we successfully perform a total extirpation of glioblastoma macroscopically, we often encounter tumor recurrence. We examined seven autopsy brains, focusing on tumor cell infiltration in the peripheral zone of a tumor, and compared our findings with the MR images. There has so far been no report regarding mapping of tumor cell infiltration and DNA histogram by flow cytometry, comparing the neuroimaging findings with the autopsy brain findings. The autopsy brain was cut in 10-mm-thick slices, in parallel with the OM line. Tissue samples were obtained from several parts in the peripheral zone (the outer area adjacent to the tumor edge as defined by postcontrast MRI) and then were examined by H&E, GFAP, and VEGF staining. We defined three infiltrating patterns based on number of infiltrated cells as follows: A zone, 100%-60% of the cells infiltrated tumor cells compared with tumor cell density of the tumor mass; B zone, 60%-20%; C zone, 20%-0%. In the autopsy brain, the tumor was easily identified macroscopically. We found that (1) the tumor cells infiltrated the peritumoral area; and (2) tumor cell infiltration was detected over an area measuring from 6 to 14 mm from the tumor border in the A zone. When performing surgery on glioblastoma, a macroscopic total extirpation of the tumor as defined by the contrast-enhanced area in MRI is therefore considered to be insufficient for successfully reducing tumor recurrence.