Bisacodyl and its cytotoxic activity on human glioblastoma stem-like cells. Implication of inositol 1,4,5-triphosphate receptor dependent calcium signaling.

Glioblastoma is the most common malignant brain tumor. The heterogeneity at the cellular level, metabolic specificities and plasticity of the cancer cells are a challenge for glioblastoma treatment. Identification of cancer cells endowed with stem properties and able to propagate the tumor in animal xenografts has opened a new paradigm in cancer therapy. Thus, to increase efficacy and avoid tumor recurrence, therapies need to target not only the differentiated cells of the tumor mass, but also the cancer stem-like cells. These therapies need to be effective on cells present in the hypoxic, slightly acidic microenvironment found within tumors. Such a microenvironment is known to favor more aggressive undifferentiated phenotypes and a slow-growing "quiescent state" that preserves the cells from chemotherapeutic agents, which mostly target proliferating cells. Based on these considerations, we performed a differential screening of the Prestwick Chemical Library of approved drugs on both proliferating and quiescent glioblastoma stem-like cells and identified bisacodyl as a cytotoxic agent with selectivity for quiescent glioblastoma stem-like cells. In the present study we further characterize bisacodyl activity and show its efficacy in vitro on clonal macro-tumorospheres, as well as in vivo in glioblastoma mouse models. Our work further suggests that bisacodyl acts through inhibition of Ca2+ release from the InsP3 receptors.

The availability of the embryonic TGF-ß protein Nodal is dynamically regulated during glioblastoma multiforme tumorigenesis.

BACKGROUND: Glioblastoma (GBM) is the most common primary brain tumor presenting self-renewing cancer stem cells. The role of these cells on the development of the tumors has been proposed to recapitulate programs from embryogenesis. Recently, the embryonic transforming growth factor-ß (TGF-ß) protein Nodal has been shown to be reactivated upon tumor development; however, its availability in GBM cells has not been addressed so far. In this study, we investigated by an original approach the mechanisms that dynamically control both intra and extracellular Nodal availability during GBM tumorigenesis. METHODS: We characterized the dynamics of Nodal availability in both stem and more differentiated GBM cells through morphological analysis, immunofluorescence of Nodal protein and of early (EEA1 and Rab5) and late (Rab7 and Rab11) endocytic markers and Western Blot. Tukey's test was used to analyze the prevalent correlation of Nodal with different endocytic markers inside specific differentiation states, and Sidak's multiple comparisons test was used to compare the prevalence of Nodal/endocytic markers co-localization between two differentiation states of GBM cells. Paired t test was used to analyze the abundance of Nodal protein, in extra and intracellular media. RESULTS: The cytoplasmic distribution of Nodal was dynamically regulated and strongly correlated with the differentiation status of GBM cells. While Nodal-positive vesicle-like particles were symmetrically distributed in GBM stem cells (GBMsc), they presented asymmetric perinuclear localization in more differentiated GBM cells (mdGBM). Strikingly, when subjected to dedifferentiation, the distribution of Nodal in mdGBM shifted to a symmetric pattern. Moreover, the availability of both intracellular and secreted Nodal were downregulated upon GBMsc differentiation, with cells becoming elongated, negative for Nodal and positive for Nestin. Interestingly, the co-localization of Nodal with endosomal vesicles also depended on the differentiation status of the cells, with Nodal seen more packed in EEA1/Rab5 + vesicles in GBMsc and more in Rab7/11 + vesicles in mdGBM. CONCLUSIONS: Our results show for the first time that Nodal availability relates to GBM cell differentiation status and that it is dynamically regulated by an endocytic pathway during GBM tumorigenesis, shedding new light on molecular pathways that might emerge as putative targets for Nodal signaling in GBM therapy.

The orthotopic xenotransplant of human glioblastoma successfully recapitulates glioblastoma-microenvironment interactions in a non-immunosuppressed mouse model.

BACKGROUND: Glioblastoma (GBM) is the most common primary brain tumor and the most aggressive glial tumor. This tumor is highly heterogeneous, angiogenic, and insensitive to radio- and chemotherapy. Here we have investigated the progression of GBM produced by the injection of human GBM cells into the brain parenchyma of immunocompetent mice. METHODS: Xenotransplanted animals were submitted to magnetic resonance imaging (MRI) and histopathological analyses. RESULTS: Our data show that two weeks after injection, the produced tumor presents histopathological characteristics recommended by World Health Organization for the diagnosis of GBM in humans. The tumor was able to produce reactive gliosis in the adjacent parenchyma, angiogenesis, an intense recruitment of macrophage and microglial cells, and presence of necrosis regions. Besides, MRI showed that tumor mass had enhanced contrast, suggesting a blood-brain barrier disruption. CONCLUSIONS: This study demonstrated that the xenografted tumor in mouse brain parenchyma develops in a very similar manner to those found in patients affected by GBM and can be used to better understand the biology of GBM as well as testing potential therapies.

Differential proteomic analysis of human glioblastoma and neural stem cells reveals HDGF as a novel angiogenic secreted factor.

Presence in glioblastomas of cancer cells with normal neural stem cell (NSC) properties, tumor initiating capacity, and resistance to current therapies suggests that glioblastoma stem-like cells (GSCs) play central roles in glioblastoma development. We cultured human GSCs endowed with all features of tumor stem cells, including tumor initiation after xenograft and radio-chemoresistance. We established proteomes from four GSC cultures and their corresponding whole tumor tissues (TTs) and from human NSCs. Two-dimensional difference gel electrophoresis and tandem mass spectrometry revealed a twofold increase of hepatoma-derived growth factor (HDGF) in GSCs as compared to TTs and NSCs. Western blot analysis confirmed HDGF overexpression in GSCs as well as its presence in GSC-conditioned medium, while, in contrast, no HDGF was detected in NSC secretome. At the functional level, GSC-conditioned medium induced migration of human cerebral endothelial cells that can be blocked by anti-HDGF antibodies. In vivo, GSC-conditioned medium induced neoangiogenesis, whereas HDGF-targeting siRNAs abrogated this effect. Altogether, our results identify a novel candidate, by which GSCs can support neoangiogenesis, a high-grade glioma hallmark. Our strategy illustrates the usefulness of comparative proteomic analysis to decipher molecular pathways, which underlie GSC properties.

Case report: Regression of Glioblastoma after flavivirus infection.

Glioblastoma is the most frequent and aggressive primary brain cancer. In preclinical studies, Zika virus, a flavivirus that triggers the death of glioblastoma stem-like cells. However, the flavivirus oncolytic activity has not been demonstrated in human patients. Here we report a glioblastoma patient who received the standard of care therapy, including surgical resection, radiotherapy and temozolomide. However, shortly after the tumor mass resection, the patient was clinically diagnosed with a typical arbovirus-like infection, during a Zika virus outbreak in Brazil. Following the infection resolution, the glioblastoma regressed, and no recurrence was observed. This clinical response continues 6 years after the glioblastoma initial diagnosis.

Tenascin-C in the extracellular matrix promotes the selection of highly proliferative and tubulogenesis-defective endothelial cells.

The extracellular matrix (ECM) contains important cues for tissue homeostasis and morphogenesis. The matricellular protein tenascin-C (TN-C) is overexpressed in remodeling tissues and cancer. In the present work, we studied the effect of different ECM-which exhibited a significant diversity in their TN-C content-in endothelial survival, proliferation and tubulogenic differentiation: autologous (endothelial) ECM devoid of TN-C, but bearing large amounts of FN; fibroblast ECM, bearing both high TN-C and FN contents; and finally, glioma-derived matrices, usually poor in FN, but very rich in TN-C. HUVECs initially adhered to the immobilized matrix produced by U373 MG glioma cells, but significantly detached and died by anoikis (50 to 80%) after 24h, as compared with cells incubated with endothelial and fibroblast matrices. Surviving endothelial cells (20 to 50%) became up to 6-fold more proliferative and formed 74-97% less tube-like structures in vitro than cells grown on non-tumoral matrices. An antibody against the EGF-like repeats of tenascin-C (TN-C) partially rescued cells from the tubulogenic defect, indicating that this molecule is responsible for the selection of highly proliferative and tubulogenic defective endothelial cells. Interestingly, by using defined substrata, in conditions that mimic glioma and normal cell ECM composition, we observed that fibronectin (FN) modulates the TN-C-induced selection of endothelial cells. Our data show that TN-C is able to modulate endothelial branching morphogenesis in vitro and, since it is prevalent in matrices of injured and tumor tissues, also suggest a role for this protein in vascular morphogenesis, in these physiological contexts.

Obstacles to Glioblastoma Treatment Two Decades after Temozolomide.

Glioblastomas are considered the most common and aggressive primary brain tumor in adults, with an average of 15 months' survival rate. The treatment is surgery resection, followed by chemotherapy with temozolomide, and/or radiotherapy. Glioblastoma must have wild-type IDH gene and some characteristics, such as TERT promoter mutation, EGFR gene amplification, microvascular proliferation, among others. Glioblastomas have great heterogeneity at cellular and molecular levels, presenting distinct phenotypes and diversified molecular signatures in each tumor mass, making it difficult to define a specific therapeutic target. It is believed that the main responsibility for the emerge of these distinct patterns lies in subcellular populations of tumor stem cells, capable of tumor initiation and asymmetric division. Studies are now focused on understanding molecular mechanisms of chemoresistance, the tumor microenvironment, due to hypoxic and necrotic areas, cytoskeleton and extracellular matrix remodeling, and in controlling blood brain barrier permeabilization to improve drug delivery. Another promising therapeutic approach is the use of oncolytic viruses that are able to destroy specifically glioblastoma cells, preserving the neural tissue around the tumor. In this review, we summarize the main biological characteristics of glioblastoma and the cutting-edge therapeutic targets that are currently under study for promising new clinical trials.

GBM-Derived Wnt3a Induces M2-Like Phenotype in Microglial Cells Through Wnt/ß-Catenin Signaling.

Glioblastoma is an extremely aggressive and deadly brain tumor known for its striking cellular heterogeneity and capability to communicate with microenvironment components, such as microglia. Microglia-glioblastoma interaction contributes to an increase in tumor invasiveness, and Wnt signaling pathway is one of the main cascades related to tumor progression through changes in cell migration and invasion. However, very little is known about the role of canonical Wnt signaling during microglia-glioblastoma crosstalk. Here, we show for the first time that Wnt3a is one of the factors that regulate interactions between microglia and glioblastoma cells. Wnt3a activates the Wnt/ß-catenin signaling of both glioblastoma and microglial cells. Glioblastoma-conditioned medium not only induces nuclear translocation of microglial ß-catenin but also increases microglia viability and proliferation as well as Wnt3a, cyclin-D1, and c-myc expression. Moreover, glioblastoma-derived Wnt3a increases microglial ARG-1 and STI1 expression, followed by an upregulation of IL-10 mRNA levels, and a decrease in IL1ß gene expression. The presence of Wnt3a in microglia-glioblastoma co-cultures increases the formation of membrane nanotubes accompanied by changes in migration capability. In vivo, tumors formed from Wnt3a-stimulated glioblastoma cells presented greater microglial infiltration and more aggressive characteristics such as growth rate than untreated tumors. Thus, we propose that Wnt3a belongs to the arsenal of factors capable of stimulating the induction of M2-like phenotype on microglial cells, which contributes to the poor prognostic of glioblastoma, reinforcing that Wnt/ß-catenin pathway can be a potential therapeutic target to attenuate glioblastoma progression.

Glioblastoma Therapy in the Age of Molecular Medicine.

Glioblastoma (GBM) is the most common and fatal primary malignant brain tumor. Despite advances in the understanding of the biology of gliomas, little has changed in the treatment of these tumors in the past decade. Phase III clinical trials showed no benefit for the use of bevacizumab in newly diagnosed patients, leading to a renewed search for new antiangiogenic drugs, as well as immunotherapeutic approaches, including checkpoint inhibitors, chimeric antigen receptor T cells, and intracerebral CpG-oligodeoxynucleotides. The emerging role of infiltrating microglia and macrophages, and of metabolic alterations, is also being taken into account in preclinical research and drug development. In this review, we discuss progress in the search for new therapeutic strategies, particularly approaches focusing on the tumor microenvironment.

p53 expression and subcellular survivin localization improve the diagnosis and prognosis of patients with diffuse astrocytic tumors.

PURPOSE: Diffuse astrocytic tumors are the most frequently occurring primary central nervous system (CNS) tumors. Their histological sub-classification into diffuse astrocytoma (DA), anaplastic astrocytoma (AA) and glioblastoma (GB) is challenging and the available prognostic factors are limited to age and tumor subtype. Biomarkers that may improve the histological sub-classification and/or serve as prognostic factors are, therefore, urgently needed. The relationship between survivin and p53 in diffuse astrocytic tumor progression and survival is currently unclear. Here, we aimed to assess the relevance of these proteins in the accuracy of the histological sub-classification of these tumors and their respective treatment responses. METHODS: One hundred and thirty-three formalin-fixed paraffin-embedded diffuse astrocytic tumor samples were included. The tumor samples were histologically reviewed and subsequently assessed for p53 and survivin expression and the presence of the IDH R132H mutation by immunohistochemistry. p53 expression levels and survivin subcellular localization patterns were correlated with histological classification and clinical outcome. RESULTS: We found that age and histological subtype were the only features with a prognostic impact. In addition, we found that high p53 expression levels and a nuclear survivin localization correlated with the AA subtype, whereas cytoplasmic survivin localization correlated with the GB subtype. We also found that patients carrying tumors with a high cytoplasmic survivin expression, a high nuclear survivin expression or a high p53 expression, and who did not receive radiotherapy, exhibited poorer short-term and long-term overall survival rates. CONCLUSIONS: Our data suggest that subcellular survivin localization and p53 expression may be employed as valuable tools to improve the accuracy of the histological sub-classification of diffuse astrocytic tumors. Patients whose tumors overexpress these proteins may benefit from radiotherapy, irrespective age and/or histological classification.

Glioblastoma entities express subtle differences in molecular composition and response to treatment.

Glioblastoma (GBM) is a grade IV astrocytoma. GBM patients show resistance to chemotherapy such as temozolomide (TMZ), the gold standard treatment. In order to simulate the molecular mechanisms behind the different chemotherapeutic responses in GBM patients we compared the cellular heterogeneity and chemotherapeutic resistance mechanisms in different GBM cell lines. We isolated and characterized a human GBM cell line obtained from a GBM patient, named GBM11. We studied the GBM11 behaviour when treated with Tamoxifen (TMX) that, among other functions, is a protein kinase C (PKC) inhibitor, alone and in combination with TMZ in comparison with the responses of U87 and U118 human GBM cell lines. We evaluated the cell death, cell cycle arrest and cell proliferation, mainly through PKC expression, by flow cytometry and western blot analysis and, ultimately, cell migration capability and f-actin filament disorganization by fluorescence microscopy. We demonstrated that the constitutive activation of p-PKC seems to be one of the main metabolic implicated on GBM malignancy. Despite of its higher resistance, possibly due to the overexpression of P-glycoprotein and stem-like cell markers, GBM11 cells presented a subtle different chemotherapeutic response compared to U87 and U118 cells. The GBM11, U87, U118 cell lines show subtle molecular differences, which clearly indicate the characterization of GBM heterogeneity, one of the main reasons for tumor resistance. The adding of cellular heterogeneity in molecular behaviour constitutes a step closer in the understanding of resistant molecular mechanisms in GBM, and can circumvents the eventual impaired therapy.

Dual treatment with shikonin and temozolomide reduces glioblastoma tumor growth, migration and glial-to-mesenchymal transition.

PURPOSE: Glioblastomas (GBM) comprise 17% of all primary brain tumors. These tumors are extremely aggressive due to their infiltrative capacity and chemoresistance, with glial-to-mesenchymal transition (GMT) proteins playing a prominent role in tumor invasion. One compound that has recently been used to reduce the expression of these proteins is shikonin (SHK), a naphthoquinone with anti-tumor properties. Temozolomide (TMZ), the most commonly used chemotherapeutic agent in GBM treatment, has so far not been studied in combination with SHK. Here, we investigated the combined effects of these two drugs on the proliferation and motility of GBM-derived cells. METHODS: The cytotoxic and proliferative effects of SHK and TMZ on human GBM-derived cells were tested using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), Ki67 staining and BrdU incorporation assays. The migration capacities of these cells were evaluated using a scratch wound assay. The expression levels of ß3 integrin, metalloproteinases (MMPs) and GMT-associated proteins were determined by Western blotting and immunocytochemistry. RESULTS: We found that GBM-derived cells treated with a combination of SHK and TMZ showed decreases in their proliferation and migration capacities. These decreases were followed by the suppression of GMT through a reduction of ß3 integrin, MMP-2, MMP-9, Slug and vimentin expression via inactivation of PI3K/AKT signaling. CONCLUSION: From our results we conclude that dual treatment with SHK and TMZ may constitute a powerful new tool for GBM treatment by reducing therapy resistance and tumor recurrence.

The Expression of Connexins and SOX2 Reflects the Plasticity of Glioma Stem-Like Cells.

Glioblastoma (GBM) is the most malignant primary brain tumor, with an average survival rate of 15 months. GBM is highly refractory to therapy, and such unresponsiveness is due, primarily, but not exclusively, to the glioma stem-like cells (GSCs). This subpopulation express stem-like cell markers and is responsible for the heterogeneity of GBM, generating multiple differentiated cell phenotypes. However, how GBMs maintain the balance between stem and non-stem populations is still poorly understood. We investigated the GBM ability to interconvert between stem and non-stem states through the evaluation of the expression of specific stem cell markers as well as cell communication proteins. We evaluated the molecular and phenotypic characteristics of GSCs derived from differentiated GBM cell lines by comparing their stem-like cell properties and expression of connexins. We showed that non-GSCs as well as GSCs can undergo successive cycles of gain and loss of stem properties, demonstrating a bidirectional cellular plasticity model that is accompanied by changes on connexins expression. Our findings indicate that the interconversion between non-GSCs and GSCs can be modulated by extracellular factors culminating on differential expression of stem-like cell markers and cell-cell communication proteins. Ultimately, we observed that stem markers are mostly expressed on GBMs rather than on low-grade astrocytomas, suggesting that the presence of GSCs is a feature of high-grade gliomas. Together, our data demonstrate the utmost importance of the understanding of stem cell plasticity properties in a way to a step closer to new strategic approaches to potentially eliminate GSCs and, hopefully, prevent tumor recurrence.

The anti-hypertensive drug prazosin inhibits glioblastoma growth via the PKCδ-dependent inhibition of the AKT pathway.

A variety of drugs targeting monoamine receptors are routinely used in human pharmacology. We assessed the effect of these drugs on the viability of tumor-initiating cells isolated from patients with glioblastoma. Among the drugs targeting monoamine receptors, we identified prazosin, an α1- and α2B-adrenergic receptor antagonist, as the most potent inducer of patient-derived glioblastoma-initiating cell death. Prazosin triggered apoptosis of glioblastoma-initiating cells and of their differentiated progeny, inhibited glioblastoma growth in orthotopic xenografts of patient-derived glioblastoma-initiating cells, and increased survival of glioblastoma-bearing mice. We found that prazosin acted in glioblastoma-initiating cells independently from adrenergic receptors. Its off-target activity occurred via a PKCδ-dependent inhibition of the AKT pathway, which resulted in caspase-3 activation. Blockade of PKCδ activation prevented all molecular changes observed in prazosin-treated glioblastoma-initiating cells, as well as prazosin-induced apoptosis. Based on these data, we conclude that prazosin, an FDA-approved drug for the control of hypertension, inhibits glioblastoma growth through a PKCδ-dependent mechanism. These findings open up promising prospects for the use of prazosin as an adjuvant therapy for glioblastoma patients.

Connective-Tissue Growth Factor (CTGF/CCN2) Induces Astrogenesis and Fibronectin Expression of Embryonic Neural Cells In Vitro.

Connective-tissue growth factor (CTGF) is a modular secreted protein implicated in multiple cellular events such as chondrogenesis, skeletogenesis, angiogenesis and wound healing. CTGF contains four different structural modules. This modular organization is characteristic of members of the CCN family. The acronym was derived from the first three members discovered, cysteine-rich 61 (CYR61), CTGF and nephroblastoma overexpressed (NOV). CTGF is implicated as a mediator of important cell processes such as adhesion, migration, proliferation and differentiation. Extensive data have shown that CTGF interacts particularly with the TGFß, WNT and MAPK signaling pathways. The capacity of CTGF to interact with different growth factors lends it an important role during early and late development, especially in the anterior region of the embryo. ctgf knockout mice have several cranio-facial defects, and the skeletal system is also greatly affected due to an impairment of the vascular-system development during chondrogenesis. This study, for the first time, indicated that CTGF is a potent inductor of gliogenesis during development. Our results showed that in vitro addition of recombinant CTGF protein to an embryonic mouse neural precursor cell culture increased the number of GFAP- and GFAP/Nestin-positive cells. Surprisingly, CTGF also increased the number of Sox2-positive cells. Moreover, this induction seemed not to involve cell proliferation. In addition, exogenous CTGF activated p44/42 but not p38 or JNK MAPK signaling, and increased the expression and deposition of the fibronectin extracellular matrix protein. Finally, CTGF was also able to induce GFAP as well as Nestin expression in a human malignant glioma stem cell line, suggesting a possible role in the differentiation process of gliomas. These results implicate ctgf as a key gene for astrogenesis during development, and suggest that its mechanism may involve activation of p44/42 MAPK signaling. Additionally, CTGF-induced differentiation of glioblastoma stem cells into a less-tumorigenic state could increase the chances of successful intervention, since differentiated cells are more vulnerable to cancer treatments.

Sirtuin-2 activity is required for glioma stem cell proliferation arrest but not necrosis induced by resveratrol.

Glioblastomas, the most common form of primary brain tumors, are the fourth cause of death by cancer in adults. Increasing evidences suggest that glioblastoma resistance to existing radio- and chemotherapies rely on glioblastoma stem cells (GSCs). GSCs are endowed with a unique combination of stem-like properties alike to normal neural stem cells (NSCs), and of tumor initiating properties. The natural polyphenol resveratrol is known to exert opposite actions on neural cells according to their normal or cancerous status. Here, we used resveratrol to explore the molecular mechanisms differing between GSCs and NSCs. We observed a dual action of resveratrol on GSCs: resveratrol blocked GSC proliferation up to 150 µM and induced their necrosis at higher doses. On the opposite, resveratrol had no effect on NSC behavior. To determine the mechanisms underlying resveratrol effects, we focused our attention on the family of NAD-dependent deacetylases sirtuins (SIRT). A member of this family, SIRT1, has been repetitively shown to constitute a preferential resveratrol target, at least in normal cells. Western blot analysis showed that SIRT1 and SIRT3 were expressed by both GSCs and NSCs whereas SIRT2 expression was restricted to GSCs. Pharmacological blockade of SIRT2 activity or down-regulation of SIRT2 expression with siRNAs counteracted the inhibitory effect of resveratrol on cell proliferation. On the contrary, inhibition of SIRT2 activity or expression did not counteract GSC necrosis observed in presence of high doses of resveratrol. Our results highlight SIRT2 as a novel target for altering GSC properties.

Gliomas and the vascular fragility of the blood brain barrier.

Astrocytes, members of the glial family, interact through the exchange of soluble factors or by directly contacting neurons and other brain cells, such as microglia and endothelial cells. Astrocytic projections interact with vessels and act as additional elements of the Blood Brain Barrier (BBB). By mechanisms not fully understood, astrocytes can undergo oncogenic transformation and give rise to gliomas. The tumors take advantage of the BBB to ensure survival and continuous growth. A glioma can develop into a very aggressive tumor, the glioblastoma (GBM), characterized by a highly heterogeneous cell population (including tumor stem cells), extensive proliferation and migration. Nevertheless, gliomas can also give rise to slow growing tumors and in both cases, the afflux of blood, via BBB is crucial. Glioma cells migrate to different regions of the brain guided by the extension of blood vessels, colonizing the healthy adjacent tissue. In the clinical context, GBM can lead to tumor-derived seizures, which represent a challenge to patients and clinicians, since drugs used for its treatment must be able to cross the BBB. Uncontrolled and fast growth also leads to the disruption of the chimeric and fragile vessels in the tumor mass resulting in peritumoral edema. Although hormonal therapy is currently used to control the edema, it is not always efficient. In this review we comment the points cited above, considering the importance of the BBB and the concerns that arise when this barrier is affected.

Glioblastoma cells: a heterogeneous and fatal tumor interacting with the parenchyma.

Glioblastomas (GBMs) are considered to be one of the deadliest human cancers, characterized by a high proliferative rate, aggressive invasiveness and insensitivity to radio- and chemotherapy, as well as a short patient survival period. Moreover, GBMs are among the most vascularized and invasive cancers in humans. Angiogenesis in GBMs is correlated with the grade of malignancy and is inversely correlated with patient survival. One of the first steps in tumor invasions is migration. GBM cells have the ability to infiltrate and disrupt physical barriers such as basement membranes, extracellular matrix and cell junctions. The invasion process includes the overexpression of several members of a super-family of zinc-based proteinases, the Metzincin, in particular a sub-group, metalloproteinases. Another interesting aspect is that, inside the GBM tissue, there are up to 30% of microglia or macrophages. However, little is known about the immune performance and interactions of the microglia with GBMs. These singular properties of GBMs will be described here. A sub-population of cells with stem-like properties may be the source of tumors since, apparently, GBM stem cells (GSCs) are highly resistant to current cancer treatments. These cancer therapies, while killing the majority of tumor cells, ultimately fail in GBM treatment because they do not eliminate GSCs, which survive to regenerate new tumors. Finally, GBM patient prognostic has shown little improvement in decades. In this context, we will discuss how the membrane-acting toxins called cytolysins can be a potential new tool for GBM treatment.