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Irradiation and temozolomide (TMZ) chemotherapy are the current standard treatments for glioblastoma multiforme (GBM), but they are associated with toxicity and limited efficacy. Recently, these standard therapies have been used to enhance immunotherapy against GBM. Immunotherapy using the anti-CD47 (immune checkpoint inhibitor) treatment has shown promise in treating multiple tumor types, including GBM. The goal of this current work was to test whether irradiation or TMZ chemotherapy could enhance anti-CD47 treatment against GBM. Our results showed that irradiation and TMZ each significantly enhanced anti-CD47-mediated phagocytosis of GBM cells in vitro. Furthermore, mice engrafted with human GBM that received anti-CD47 combined with focal irradiation or TMZ treatment showed a significant increase in the survival rate compared to those that received a single treatment. The tumor growth in mice that received both anti-CD47 and irradiation was significantly less than that of groups that received either anti-CD47 or focal irradiation. The results from this study may support future use of anti-CD47 treatment in combination with irradiation or chemotherapy to enhance the therapeutic efficacy of GBM treatment.

Maritime transport is responsible for about 2.5% of global greenhouse gas emissions representing around 1000 million tons of CO $$_2$$ annually. The situation of shipping emissions that strongly depends on future economic grows is aggravated by the fact that global green house gas (GHG) emissions are predicted to increase between 50 and 250% by 2050. This is not compatible with the internationally agreed goal of keeping global temperature increase below to $$2\,^{\circ }\hbox {C}$$ compared to pre-industrial levels, which requires worldwide emissions to be at least halved from 1990 levels by 2050. Furthermore, ship owners are facing barriers implementing energy efficiency technologies to reduce CO $$_2$$ mainly due to reliability, and financial and economic constraints as well as due to the complexity of change. Energy consumption and CO $$_2$$ emissions of ships could be reduced by applying operational measures and implementing existing technologies. Further reductions could be achieved by implementing new innovative technologies. The aim of this study is to compare and review low carbon and advanced technologies that may help to reach international GHG reduction goals. A comparison table describing the different technologies, the estimated capital cost, technology readiness as well as the potential GHG reduction is drawn. The table also indicates if the technology suits better to new projects or to retrofitting. The comparison may help the key players to select the most convenient technology for their new projects. It will also be helpful for conversion of existing vessels.

The correlation between BMP-2 and osteosarcoma growth has gained increased interest in the recent years, however, there is still no consensus. In this study, we tested the effects of BMP-2 on osteosarcoma cells through both in vitro and in vivo experiments. The effect of BMP-2 on the proliferation, migration and invasion of osteosarcoma cells was tested in vitro. Subcutaneous and intratibial tumor models were used for the in vivo experiments in nude mice. The effects of BMP-2 on EMT of osteosarcoma cells and the Wnt/β-catenin signaling pathway were also tested using a variety of biochemical methods. In vitro tests did not show a significant effect of BMP-2 on tumor cell proliferation. However, BMP-2 increased the mobility of tumor cells and the invasion assay demonstrated that BMP-2 promoted invasion of osteosarcoma cells in vitro. In vivo animal study showed that BMP-2 dramatically enhanced tumor growth. We also found that BMP-2 induced EMT of osteosarcoma cells. The expression levels of Axin2 and Dkk-1 were both down regulated by BMP-2 treatment, while β-catenin, c-myc and Cyclin-D1 were all upregulated. The expression of Wnt3α and p-GSK-3β were also significantly upregulated indicating that the Wnt/β-catenin signaling pathway was activated during the EMT of osteosarcoma driven by BMP-2. From this study, we can conclude that BMP-2 significantly promotes growth of osteosarcoma cells (143B, MG63), and enhances mobility and invasiveness of tumor cells as demonstrated in vitro. The underlying mechanism might be that BMP-2 promotes EMT of osteosarcoma through the Wnt/β-catenin signaling pathway. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1638-1648, 2019.

Significance Tumor-associated microglia and macrophages (TAMs) constitute up to one half of the cells in glioblastoma multiforme (GBM) and are known to promote tumor growth. Therefore, modulation and reeducation of the TAM pool is a promising antitumor strategy against GBMs. We recently showed that disruption of the SIRPα-CD47 signaling axis is efficacious against various brain tumors including GBM primarily by inducing tumor phagocytosis. Here, we show that tumor-associated microglia are capable of in vivo tumor cell phagocytosis in response to anti-CD47 blockade. The activation of microglia was associated with distinct morphological and transcriptional changes. In fact, microglia show a dampened inflammatory response upon anti-CD47 therapy compared with macrophages, making them an attractive target for clinical applications especially in the confined regions of the brain., Glioblastoma multiforme (GBM) is a highly aggressive malignant brain tumor with fatal outcome. Tumor-associated macrophages and microglia (TAMs) have been found to be major tumor-promoting immune cells in the tumor microenvironment. Hence, modulation and reeducation of tumor-associated macrophages and microglia in GBM is considered a promising antitumor strategy. Resident microglia and invading macrophages have been shown to have distinct origin and function. Whereas yolk sac-derived microglia reside in the brain, blood-derived monocytes invade the central nervous system only under pathological conditions like tumor formation. We recently showed that disruption of the SIRPα-CD47 signaling axis is efficacious against various brain tumors including GBM primarily by inducing tumor phagocytosis. However, most effects are attributed to macrophages recruited from the periphery but the role of the brain resident microglia is unknown. Here, we sought to utilize a model to distinguish resident microglia and peripheral macrophages within the GBM-TAM pool, using orthotopically xenografted, immunodeficient, and syngeneic mouse models with genetically color-coded macrophages (Ccr2RFP) and microglia (Cx3cr1GFP). We show that even in the absence of phagocytizing macrophages (Ccr2RFP/RFP), microglia are effector cells of tumor cell phagocytosis in response to anti-CD47 blockade. Additionally, macrophages and microglia show distinct morphological and transcriptional changes. Importantly, the transcriptional profile of microglia shows less of an inflammatory response which makes them a promising target for clinical applications.

Osteosarcoma (OS) is a malignant bone tumor and its occurrence is associated with high levels of microRNAs (miRNAs) and critical protein sinvolved on intracellular signaling pathways. Cisplatin and Doxorubicin are employed on chemotherapy, but their use cause side effects and contributes to multidrug resistance. Since several tripodal amines have been studied as anticancer agents, tris(2-pyridylmethyl)amine (TPA) was investigated against osteosarcoma cells. Here we show that TPA exhibits activity against MG-63 and Saos-2 cells. Cyclic voltammetry results indicate an interaction between TPA and dsDNA, denoted by blocking of the proton-assisted reduction of the 2-pyridylmethyl moiety in the presence of the biomolecule. Molecular docking studies indicate binding modes between TPA and DNA, as well as other crucial biological targets related to OS pathology. In addition, ADMET in silico prediction results suggest a good pharmacokinetic and toxicity profile for TPA.

The transformation of waste oils and fats into biofuels attracts great interest due to the low cost of these materials. The thermal and/or catalytic cracking of oils and fats is an alternative route to the classic transesterification process of biodiesel production when the raw material has low quality. In this work, thermal cracking of sodium soaps of residual fatty materials from Brazilian restaurants (brown grease mainly composed of fatty acids of soybean oil) was tested to assess the feasibility of yielding a high quality diesel-like product. The reactions occurred in a single stirred steel reactor of 300 ml at high temperatures (723 °K) at atmospheric pressure for 1h45 min. The organic liquid product was analyzed for acid and saponification value, thermogravimetric characteristics. The chemical composition of the liquid product diesel-like fractions was determined by FT-IR, Nuclear Magnetic Resonance Spectroscopy (NMR 1H and 13C) and GC–MS. The hydrocarbons obtained were very similar to diesel oil and suitable for use, in pure form or in mixtures, in diesel oil engines. Yields above 60% and very low acidity (0.5 mg KOH/g) were obtained, meeting the requirements of ANP (Brazilian National Petroleum Agency) Resolution No 51 de 25/11/15.

The original version of this Article omitted Suzana A. Kahn, Siddhartha S. Mitra & Samuel H. Cheshier as jointly supervising authors. This has now been corrected in both the PDF and HTML versions of the Article.

Medulloblastoma is the most common malignant brain tumor of childhood. Group 3 medulloblastoma, the most aggressive molecular subtype, frequently disseminates through the leptomeningeal cerebral spinal fluid (CSF) spaces in the brain and spinal cord. The mechanism of dissemination through the CSF remains poorly understood, and the molecular pathways involved in medulloblastoma metastasis and self-renewal are largely unknown. Here we show that NOTCH1 signaling pathway regulates both the initiation of metastasis and the self-renewal of medulloblastoma. We identify a mechanism in which NOTCH1 activates BMI1 through the activation of TWIST1. NOTCH1 expression and activity are directly related to medulloblastoma metastasis and decreased survival rate of tumor-bearing mice. Finally, medulloblastoma-bearing mice intrathecally treated with anti-NRR1, a NOTCH1 blocking antibody, present lower frequency of spinal metastasis and higher survival rate. These findings identify NOTCH1 as a pivotal driver of Group 3 medulloblastoma metastasis and self-renewal, supporting the development of therapies targeting this pathway., Group 3 medulloblastoma is an aggressive pediatric brain tumour that disseminates through the leptomeningeal cerebral spinal fluid. Here, the authors show that in Group 3 medulloblastoma NOTCH1 activates BMI1 through the activation of TWIST1, driving metastasis and self-renewal, and in mouse models a NOTCH1 blocking antibody decreased spinal metastases.

Glioblastoma (GBM) is the most common and aggressive malignant primary brain tumor and still lacks effective therapeutic strategies. It has already been shown that old drugs like sulfasalazine (SAS) and valproic acid (VPA) present antitumoral activities in glioma cell lines. SAS has also been associated with a decrease of intracellular glutathione (GSH) levels through a potent inhibition of xc- glutamate/cystine exchanger leading to an antioxidant deprotection. In the same way, VPA was recently identified as a histone deacetylase (HDAT) inhibitor capable of activating tumor suppression genes. As both drugs are widely used in clinical practice and their profile of adverse effects is well known, the aim of our study was to investigate the effects of the combined treatment with SAS and VPA in GBM cell lines. We observed that both drugs were able to reduce cell viability in a dose-dependent manner and the combined treatment potentiated these effects. Combined treatment also increased cell death and inhibited proliferation of GBM cells, while having no effect on human and rat cultured astrocytes. Also, we observed high protein expression of the catalytic subunit of xc- in all the examined GBM cell lines, and treatment with SAS blocked its activity and decreased intracellular GSH levels. Noteworthy, SAS but not VPA was also able to reduce the [14C]-ascorbate uptake. Together, these data indicate that SAS and VPA exhibit a substantial effect on GBM cell’s death related to an intracellular oxidative response imbalance, making this combination of drugs a promising therapeutic strategy.

International audience; 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 Ca(2+) release from the InsP3 receptors.

Morbidity and mortality associated with pediatric malignant primary brain tumors remain high in the absence of effective therapies. Macrophage-mediated phagocytosis of tumor cells via blockade of the anti-phagocytic CD47-SIRPα interaction using anti-CD47 antibodies has shown promise in preclinical xenografts of various human malignancies. We demonstrate the effect of a humanized anti-CD47 antibody, Hu5F9-G4, on five aggressive and etiologically distinct pediatric brain tumors: group 3 medulloblastoma (primary and metastatic), atypical teratoid rhabdoid tumor, primitive neuroectodermal tumor, pediatric glioblastoma, and diffuse intrinsic pontine glioma. Hu5F9-G4 demonstrated therapeutic efficacy in vitro and in vivo in patient-derived orthotopic xenograft models. Intraventricular administration of Hu5F9-G4 further enhanced its activity against disseminated medulloblastoma leptomeningeal disease. Notably, Hu5F9-G4 showed minimal activity against normal human neural cells in vitro and in vivo, a phenomenon reiterated in an immunocompetent allograft glioma model. Thus, Hu5F9-G4 is a potentially safe and effective therapeutic agent for managing multiple pediatric central nervous system malignancies.

Microparticulate films of a canthin-6-one alkaloid ( L ), a natural β-carboline alkaloid presenting a characteristic naphtyridone motif, on glassy carbon electrodes yield different, separate voltammetric signals for dsDNA, ssDNA, G-quadruplex DNA, different degrees of DNA methylation and the biomimetic nucleosomal DNA with detection limit of 10 −5 M. This multiple-signal electrochemical behavior is in contrast with conventional use of DNA intercalators, only discriminating between different DNA forms by variations in the intensity of a unique signal. Complementary photochemical and scanning electrochemical microscopy (SECM) data suggest that the differences in the voltammetric response of the different DNA forms derive from the intercalating properties of the canthin-6-one.

Glioblastoma (GBM) is considered incurable due to its resistance to current cancer treatments. So far, all clinically available alternatives for treating GBM are limited, evoking the development of novel treatment strategies that can more effectively manage these tumors. Extensive effort is being dedicated to characterize the molecular basis of GBM resistance to chemotherapy and to explore novel therapeutic procedures that may improve overall survival. Cytolysins are toxins that form pores in target cell membranes, modifying ion homeostasis and leading to cell death. These pore-forming toxins might be used, therefore, to enhance the efficiency of conventional chemotherapeutic drugs, facilitating their entrance into the cell. In this study, we show that a non-cytotoxic concentration of equinatoxin II (EqTx-II), a pore-forming toxin from the sea anemone Actinia equina, potentiates the cytotoxicity induced by temozolomide (TMZ), a first-line GBM treatment, and by etoposide (VP-16), a second- or third-line GBM treatment. We also suggest that this effect is selective to GBM cells and occurs via PI3K/Akt pathway inhibition. Finally, Magnetic resonance imaging (MRI) revealed that a non-cytotoxic concentration of EqTx-II potentiates the VP-16-induced inhibition of GBM growth in vivo. These combined therapies constitute a new and potentially valuable tool for GBM treatment, leading to the requirement of lower concentrations of chemotherapeutic drugs and possibly reducing, therefore, the adverse effects of chemotherapy.

Brain tumor-initiating cells (BTICs) are self-renewing multipotent cells critical for tumor maintenance and growth. Using single-cell microfluidic profiling, we identified multiple subpopulations of BTICs coexisting in human glioblastoma, characterized by distinct surface marker expression and single-cell molecular profiles relating to divergent bulk tissue molecular subtypes. These data suggest BTIC subpopulation heterogeneity as an underlying source of intra-tumoral bulk tissue molecular heterogeneity, and will support future studies into BTIC subpopulation-specific therapies.

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-β (TGF-β) 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. Electronic supplementary material The online version of this article (doi:10.1186/s12935-016-0324-3) contains supplementary material, which is available to authorized users.

Published online; International audience; 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 a1-and a2B-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 PKCd-dependent inhibition of the AKT pathway, which resulted in caspase-3 activation. Blockade of PKCd 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 hyperten-sion, inhibits glioblastoma growth through a PKCd-dependent mechanism. These findings open up promising prospects for the use of prazosin as an adjuvant therapy for glioblastoma patients.

Background: Synapse formation and function is modulated by intrinsic and extrinsic non-autonomous factors. Results: Astrocytes induce synapse formation through TGF-β1 pathway. TGF-β1 synaptogenic property is dependent on d-serine signaling. Conclusion: TGF-β induces excitatory glutamatergic synapses in vertebrates. Significance: This is a novel molecular mechanism that might impact synaptic function and shed light on new potential therapeutic targets for synaptic deficit diseases., Assembly of synapses requires proper coordination between pre- and postsynaptic elements. Identification of cellular and molecular events in synapse formation and maintenance is a key step to understand human perception, learning, memory, and cognition. A key role for astrocytes in synapse formation and function has been proposed. Here, we show that transforming growth factor β (TGF-β) signaling is a novel synaptogenic pathway for cortical neurons induced by murine and human astrocytes. By combining gain and loss of function approaches, we show that TGF-β1 induces the formation of functional synapses in mice. Further, TGF-β1-induced synaptogenesis involves neuronal activity and secretion of the co-agonist of the NMDA receptor, d-serine. Manipulation of d-serine signaling, by either genetic or pharmacological inhibition, prevented the TGF-β1 synaptogenic effect. Our data show a novel molecular mechanism that might impact synaptic function and emphasize the evolutionary aspect of the synaptogenic property of astrocytes, thus shedding light on new potential therapeutic targets for synaptic deficit diseases.

Introduction: Modulation of macrophages and microglia (tumor associated macrophages, TAMs) in glioblastoma (GBM) poses a strategy against the disease. But little is known about the composition of the TAM-pool and the role of GBM subtypes in shaping their microenvironment. Thus, we sought to decipher the contribution of peripheral macrophages and microglia to the GBM-TAM-pool and their response to myeloid modulation such as CD47-Sirpa disruption with CD47 blocking antibodies. Methods: We generated immunodeficient mice with genetically color-coded macrophages and microglia. B6 Ccr2Rfp/+Cx3cr1Gfp/+ mice were crossed to NSG (NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ)-mice, and termed Ccr2Rfp/+Cx3cr1Gfp/+NSG-mice. Further, Ccr2Rfp/RfpCx3cr1Gfp/+NSG-mice devoid of macrophage influx to the brain were generated. Mice were grafted with patient-derived GBM cell lines transduced with EBFP2-luciferase, and treated with anti-CD47 Mab. At endpoint, tumors were analyzed by flow cytometry to assess TAM composition, polarization and phagocytosis, and both microglial and macrophage TAMs sorted for RNAseq analysis. Plasma cytokines were assessed. Further, brain tumors were imaged through cranial windows using in vivo confocal and 2-photon microscopy to monitor macrophage and microglial phagocytosis and behavior upon anti-CD47 treatment in real time. Results: The composition of the TAM pool was highly variable depending on the xenografted cell line. While TAMs in diffuse, slow growing tumors almost exclusively consisted of microglia, high-passage mesenchymal and classical GBM lines induced significant peripheral macrophage influx. In contrast, TAMs of proneural tumors only had a minor macrophage component. Anti-CD47 treatment induced macrophage and microglial phagocytosis and a marked microglial morphology change assessed by intracranial in vivo imaging and flow-cytometry. Furthermore, anti-CD47 treatment led to modest peripheral macrophage recruitment to the tumor site in the absence of Ccr2. Anti-CD47 treatment in absence of Ccr2 was accompanied by a stronger proinflammatory cytokine profile compared to wildtype, and significantly improved survival of tumor burdened mice in presence or absence of Ccr2. RNAseq analysis of sorted macrophages and microglia after anti-CD47 treatment revealed a transcriptional change towards a proinflammatory and M1-polarized signature in macrophages, whereas microglia displayed a distinct loss of M2-related genes. Conclusion: The GBM TAM pool is dynamic and dependent on tumor- specific characteristics. Resident microglia by themselves are able to respond to anti-CD47 treatment and act as phagocytic effector cells that reduce GBM growth and improve survival. Additional recruitment and reprogramming of peripheral macrophages by CD47-blockade boosts the therapeutic response and points towards macrophage-microglial cooperativity.

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.

D-serine is a co-agonist of NMDA receptor (NMDAR) and plays important roles in synaptic plasticity mechanisms. Serine racemase (SR) is a brain-enriched enzyme that converts L-serine to D-serine. SR interacts with the protein interacting with C-kinase 1 (PICK1), which is known to direct protein kinase C (PKC) to its targets in cells. Here, we investigated whether PKC activity regulates SR activity and D-serine availability in the brain. In vitro, PKC phosphorylated SR and decreased its activity. PKC activation increased SR phosphorylation in serine residues and reduced D-serine levels in astrocyte and neuronal cultures. Conversely, PKC inhibition decreased basal SR phosphorylation and increased cellular D-serine levels. In vivo modulation of PKC activity regulated both SR phosphorylation and D-serine levels in rat frontal cortex. Finally, rats that completed an object recognition task showed decreased SR phosphorylation and increased D-serine/total serine ratios, which was markedly correlated with decreased PKC activity in both cortex and hippocampus. Results indicate that PKC phosphorylates SR in serine residues and regulates D-serine availability in the brain. This interaction may be relevant for the regulation of physiological and pathological mechanisms linked to NMDAR function.

Medulloblastoma (MB) is the most common malignant pediatric brain tumor, accounting for about 20% of all cases. While surgery, craniospinal irradiation, and chemotherapy have resulted in a cure rate of 70%, the surviving patients are afflicted with neurocognitive impairment, endocrine dysfunction, and a severe decrease in quality of life. Consequently, better and more effective treatments are needed to treat these young patients. Casein kinase 2 (CK2) is an intriguing therapeutic target for MB because it is dysregulated in all the MB molecular subgroups and patients with high CK2 expression have a significantly worse prognosis. To elucidate the role of CK2 in MB we transduced multiple MB cell lines with CK2 isoforms. We discovered that a CK2 isoform, CK2a, increased tumorigenesis in both the Sonic Hedgehog and Group 3 MB subgroups, while knocking down expression ameliorated MB growth. Through these transduced cell lines we also determined that CK2 can regulate MB tumorigenesis through b-catenin and potentially GLI1. Moreover, mice orthotopically injected with MB cells over-expressing CK2a or CK2b displayed a reduced survival compared to control. We extended our analysis to a CK2 inhibitor, CX-4945, which is currently undergoing phase I/II clinical trials for toxicity and safety. Treatment with CX-4945 reduced MB cell growth and also reduced expression of MGMT, a well-known regulator of temozolomide (TMZ) efficacy. Our findings were corroborated when we screened 4,000 FDA approved compounds to identify molecules that work synergistically with CX-4945. TMZ was one of the major compounds that were identified in the screen, suggesting that CX-4945 treatment can sensitize MB cells to TMZ by dysregulating MGMT. Combinatorial treatment with CX-4945 and TMZ had a synergistic effect on reducing MB tumor growth. Together, our findings suggest that CK2 is a novel therapeutic target for MB and that combining CX-4945 and TMZ can lead to a promising new MB therapy. Citation Format: Ryan Nitta, Sara Matilda Bolin, Ginikachi Nwagbo, Teresa Purzner, Suzana Kahn, Yoon-Jae Cho, Gordon Li. Casein kinase 2 is a major regulator of medulloblastoma growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-322.

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 TGFβ, 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.

BACKGROUND: Side effects of current pediatric brain tumor therapeutics, usually resulting from neural cell toxicity, call for testing of novel therapeutic modalities on appropriate preclinical models, which recapitulates normal human neural environment with malignant brain tumors. Here, we present a new model to study toxicity of humanized antibodies against xenografted human normal neural cells sequentially co-transplanted with primary medulloblastoma (MB) cells. METHODS: Human neural progenitor cells (HuNPCs) derived from human fetal neural tissue, were infected with td-Tomato-luciferase expressing virus and injected into newborn pups (p1-p3 days old). HuNPC engraftment was confirmed with bioluminescence imaging and previously characterized for multi-potent differentiation into neurons, astrocytes and oligodendrocytes. HuNPC engrafted mice were then injected with unlabeled human MB cells at 1.5 months of age. MB cells used were previously confirmed to have 100% penetrance in multiple cohorts. After 2 weeks of tumor cell transplantation, mice were randomized and treated with either humanized anti-CD47 monoclonal antibody (HuCD47 mAb) or control. Human neural cells viability and proliferation in all mice were measured through subsequent bioluminescence imaging. RESULTS: Follow-up bioluminescence imaging revealed minimal change in flux values of treated mice with HuCD47 mAb, representing viability of engrafted normal neural cell, compared to control. Moreover, survival rates as well as subsequent H & E staining show HuCD47 mAb dramatically decreased tumor size and subsequently increased the survival of mice treated with HuCD47 mAb compared to control similar to experiments carried out in mice transplanted with human MB cells only. CONCLUSION: The presented in vivo model provides a new platform to test any novel potential therapeutic (here, HuCD47 mAb) in the context of xenografted human normal neural environment. This way we not only measure effect of the proposed drug on tumor regression but impact of developed agent on human normal neural tissue in the vicinity of the tumor.

Background Glioblastoma (GBM) is the most malignant primary brain tumor in adults, with a median survival time of one and a half years. Traditional treatments, including radiation, chemotherapy, and surgery, are not curative, making it imperative to find more effective treatments for this lethal disease. γ-Glutamyl transferase (GGT) is a family of enzymes that was shown to control crucial redox-sensitive functions and to regulate the balance between proliferation and apoptosis. GGT7 is a novel GGT family member that is highly expressed in brain and was previously shown to have decreased expression in gliomas. Since other members of the GGT family were found to be altered in a variety of cancers, we hypothesized that GGT7 could regulate GBM growth and formation. Methods To determine if GGT7 is involved in GBM tumorigenesis, we modulated GGT7 expression in two GBM cell lines (U87-MG and U138) and monitored changes in tumorigenicity in vitro and in vivo. Results We demonstrated for the first time that GBM patients with low GGT7 expression had a worse prognosis and that 87% (7/8) of primary GBM tissue samples showed a 2-fold decrease in GGT7 expression compared to normal brain samples. Exogenous expression of GGT7 resulted in a 2- to 3-fold reduction in proliferation and anchorage-independent growth under minimal growth conditions (1% serum). Decreasing GGT7 expression using either short interfering RNA or short hairpin RNA consistently increased proliferation 1.5- to 2-fold. In addition, intracranial injections of U87-MG cells with reduced GGT7 expression increased tumor growth in mice approximately 2-fold, and decreased mouse survival. To elucidate the mechanism by which GGT7 regulates GBM growth, we analyzed reactive oxygen species (ROS) levels in GBM cells with modulated GGT7 expression. We found that enhanced GGT7 expression reduced ROS levels by 11-33%. Conclusion Our study demonstrates that GGT7 is a novel player in GBM growth and that GGT7 can play a critical role in tumorigenesis by regulating anti-oxidative damage. Loss of GGT7 may increase the cellular ROS levels, inducing GBM occurrence and growth. Our findings suggest that GGT7 can be a promising biomarker and a potential therapeutic target for GBM. Electronic supplementary material The online version of this article (doi:10.1186/s12885-015-1232-y) contains supplementary material, which is available to authorized users.

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 blood brain barrier and the concerns that arise when this barrier is affected.

Osteosarcoma is the most common primary bone tumor in children and young adults. The median survival of osteosarcoma patients has not significantly improved since 1990, despite administration of different classes of chemotherapy agents, such as methotrexate, cisplatin and doxorubicin. Cancer stem cells (CSCs) are responsible for the resistance of osteosarcoma to chemotherapy and OCT4, SOX2 and SSEA4 have been used to identify CSCs in osteosarcoma. Here, we used low-passage patient-derived osteosarcoma cells and osteosarcoma cells directly isolated from patients before and after chemotherapy treatments to evaluate the effects of chemotherapy on stem cell markers expression. We demonstrate that primary osteosarcoma cells are resistant to methotrexate treatment and sensitive to cisplatin and doxorubicin in vitro. We also verified that cisplatin and doxorubicin reduce the expression of SOX2 and OCT4 in primary osteosarcoma cells whereas methotrexate does not alter SOX2 and OCT4 expression, however it increases SSEA4 expression in primary osteosarcoma cells. Finally, we found that, although the combination treatment cisplatin plus doxorubicin inhibited the in vivo growth of osteosarcoma cells in NOD-SCID gamma mice subcutaneously injected with SaOs2, the combination treatment cisplatin plus doxorubicin plus methotrexate did not inhibit the in vivo growth of these cells. These observations may provide an explanation for the poor response of osteosarcomas to chemotherapy and point to the need of reevaluating the therapeutic strategies for human osteosarcomas.

Tumors of the central nervous system are challenging to treat due to the limited effectiveness and associated toxicities of chemotherapy and radiation therapy. For tumors that can be removed surgically, extent of malignant tissue resection has been shown to correlate with disease progression, recurrence, and survival. Thus, improved technologies for real-time brain tumor imaging are critically needed as tools for guided surgical resection. We previously engineered a novel peptide that binds with high affinity and unique specificity to α V β 3 , α V β 5 , and α 5 β 1 integrins, which are present on tumor cells, and the vasculature of many cancers, including brain tumors. In the current study, we conjugated this engineered peptide to a near infrared fluorescent dye (Alexa Fluor 680), and used the resulting molecular probe for noninvasive whole body imaging of patient-derived medulloblastoma xenograft tumors implanted in the cerebellum of mice. The engineered peptide exhibited robust targeting and illumination of intracranial medulloblastoma following both intravenous and intraperitoneal injection routes. In contrast, a variant of the engineered peptide containing a scrambled integrin-binding sequence did not localize to brain tumors, demonstrating that tumor-targeting is driven by specific integrin interactions. Ex vivo imaging was used to confirm the presence of tumor and molecular probe localization to the cerebellar region. These results warrant further clinical development of the engineered peptide as a tool for image-guided resection of central nervous system tumors.

Among the cells that constitute the central nervous system (CNS), astrocytes are the most abundant cells in the brain. They originate from the neural tube, differently from other glial cells of the astrocyte-like, enteric glia, which originate from the neural crest. Cerebral astrocytes interact with other brain cells such as neurons, mediated by cellular contact involving extracellular matrix (ECM) elements and the integrin of astrocytes. Interactions can also occur through exchange of soluble molecules, cytokines, and growth factors, delivered by astrocytes and the interacting cells. Of the growth factors secreted by astrocytes, members of the transforming growth factor (TGF) beta family, especially TGF-β1, are highly important. TGF-β1 acts in brain development, in adult brain homeostasis, and also in orchestrating the brain’s response to injury and/or aging. These cell–cell interactions depend on the cellular membrane plasticity expressed by biophysical forces of interaction. In parallel to the properties of normal astrocytes, a growing astrocytoma develops new malignant behavior and interactions with parenchyma that differ from those of normal astrocytes. In this chapter, we analyze important points that characterize tumor progression and discuss new therapeutic approaches to treat these tumors.

The development of reliable, clinically relevant in vivo tumor model systems for central nervous system neoplasms is of paramount importance in the advancement of basic and translational research. Discrepancies between preclinical and clinical results of anticancer therapeutic agents demand reliable research platforms that can precisely recapitulate the behavior of such cancers. One approach that has gained great traction in neuro-oncological research is that of primary xenografts, whereby patient-derived tumors are dissociated and maintained by subsequent serial passaging prior to intracranial injection within animal lines. Herein, we describe our experiences in the development of murine models for glioblastoma (GBM), atypical teratoid rhabdoid tumor (ATRT), and medulloblastoma. This technique is a general method to introduce neoplasms through intracranial stereotactic xenograft injections in mice.

International audience; Glioblastomas (GBMs) are devastating tumors of the central nervous system, with a poor prognosis of 1-year survival. This results from a high resistance of GBM tumor cells to current therapeutic options, including etoposide (VP-16). Understanding resistance mechanisms may thus open new therapeutic avenues. VP-16 is a topoisomerase inhibitor that causes replication fork stalling and, ultimately, the formation of DNA double-strand breaks and apoptotic cell death. Autophagy has been identified as a VP-16 treatment resistance mechanism in tumor cells. Retinoblastoma protein (RB) is a classical tumor suppressor owing to its role in G1/S cell cycle checkpoint, but recent data have shown RB participation in many other cellular functions, including, counterintuitively, negative regulation of apoptosis. As GBMs usually display an amplification of the EGFR signaling involving the RB protein pathway, we questioned whether RB might be involved in mechanisms of resistance of GBM cells to VP-16. We observed that RB silencing increased VP-16-induced DNA double-strand breaks and p53 activation. Moreover, RB knockdown increased VP-16-induced apoptosis in GBM cell lines and cancer stem cells, the latter being now recognized essential to resistance to treatments and recurrence. We also showed that VP-16 treatment induced autophagy, and that RB silencing impaired this process by inhibiting the fusion of autophagosomes with lysosomes. Taken together, our data suggest that RB silencing causes a blockage on the VP-16-induced autophagic flux, which is followed by apoptosis in GBM cell lines and in cancer stem cells. Therefore, we show here, for the first time, that RB represents a molecular link between autophagy and apoptosis, and a resistance marker in GBM, a discovery with potential importance for anticancer treatment.

Bone marrow stromal cells (BMSCs) are a valuable resource for skeletal regenerative medicine because of their osteogenic potential. In spite of the very general term “stem cell,” this population of cells is far from homogeneous, and different BMSCs clones have greatly different phenotypic properties and, therefore, potentially different therapeutic potential. Adherence to a culture flask surface is a primary defining characteristic of BMSCs. We hypothesized that based on the adherence time we could obtain an enriched population of cells with a greater therapeutic potential. We characterized two populations of bone marrow-derived cells, those that adhered by three days (R-cells) and those that did not adhere by three days but did by six days (L-cells). Clones derived from L-cells could be induced into adipogenic, chondrogenic, and osteogenic differentiationin vitro. L-cells appeared to have greater proliferative capacity, as manifested by larger colony diameter and clones with higher CD146 expression. Only clones from L-cells developed bone marrow stromain vivo. We conclude that the use of late adherence of BMSCs is one parameter that can be used to enrich for cells that will constitute a superior final product for cell therapy in orthopedics.

Cancer stem cells, identified in gliomas as well as in other cancer types, are defined as undifferentiated cells with the ability to self-renew, differentiate to multiple lineages, and initiate tumors that mimic the parent tumor. Glioma stem cells are resistant to radiotherapy and chemotherapy and play a major role in repopulating tumors following treatment. An integrated view of the markers, niche, and vasculature, as well as therapeutic resistance, is essential to understand the key processes occurring within glioma stem cells and, therefore, to identify potential therapeutic targets that can lead to the development of more effective cancer treatments.

Tumor-associated macrophages (TAMs) represent an important cellular subset within the glioblastoma (WHO grade IV) microenvironment and are a potential therapeutic target. TAMs display a continuum of different polarization states between antitumorigenic M1 and protumorigenic M2 phenotypes, with a lower M1/M2 ratio correlating with worse prognosis. Here, we investigated the effect of macrophage polarization on anti-CD47 antibody-mediated phagocytosis of human glioblastoma cells in vitro, as well as the effect of anti-CD47 on the distribution of M1 versus M2 macrophages within human glioblastoma cells grown in mouse xenografts. Bone marrow-derived mouse macrophages and peripheral blood-derived human macrophages were polarized in vitro toward M1 or M2 phenotypes and verified by flow cytometry. Primary human glioblastoma cell lines were offered as targets to mouse and human M1 or M2 polarized macrophages in vitro. The addition of an anti-CD47 monoclonal antibody led to enhanced tumor-cell phagocytosis by mouse and human M1 and M2 macrophages. In both cases, the anti-CD47-induced phagocytosis by M1 was more prominent than that for M2. Dissected tumors from human glioblastoma xenografted within NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice and treated with anti-CD47 showed a significant increase of M1 macrophages within the tumor. These data show that anti-CD47 treatment leads to enhanced tumor cell phagocytosis by both M1 and M2 macrophage subtypes with a higher phagocytosis rate by M1 macrophages. Furthermore, these data demonstrate that anti-CD47 treatment alone can shift the phenotype of macrophages toward the M1 subtype in vivo.

Glioblastoma (GBM) is one of the most aggressive human cancers. Despite current advances in multimodality therapies, such as surgery, radiotherapy and chemotherapy, the outcome for patients with high grade glioma remains fatal. The knowledge of how glioma cells develop and depend on the tumor environment might open opportunities for new therapies. There is now a growing awareness that the main limitations in understanding and successfully treating GBM might be bypassed by the identification of a distinct cell type that has defining properties of somatic stem cells, as well as cancer-initiating capacity - brain tumor stem cells, which could represent a therapeutic target. In addition, experimental studies have demonstrated that the combination of antiangiogenic therapy, based on the disruption of tumor blood vessels, with conventional chemotherapy generates encouraging results. Emerging reports have also shown that microglial cells can be used as therapeutic vectors to transport genes and/or substances to the tumor site, which opens up new perspectives for the development of GBM therapies targeting microglial cells. Finally, recent studies have shown that natural toxins can be conjugated to drugs that bind to overexpressed receptors in cancer cells, generating targeted-toxins to selectively kill cancer cells. These targeted-toxins are highly effective against radiation- and chemotherapy-resistant cancer cells, making them good candidates for clinical trials in GBM patients. In this review, we discuss recent studies that reveal new possibilities of GBM treatment taking into account cancer stem cells, angiogenesis, microglial cells and drug delivery in the development of new targeted-therapies.

International audience; Zanthoxylum chiloperone var. angustifolium root bark was studied with the aim of finding novel molecules able to overcome cancer stem cell chemoresistance. Purification of a methanol-soluble extract resulted in the isolation of a known pyranocoumarin, trans-avicennol (1). Compound 1 demonstrated antiproliferative activity on glioma-initiating cells, whereas it was inactive on human neural stem cells. trans-Avicennol (1) activated the MAPK/ERK pathway and was also evaluated for its ability to inhibit the enzyme indoleamine-2,3-dioxygenase.

D-serine is a co-agonist of NMDA receptor (NMDAR) and plays important roles in synaptic plasticity mechanisms. Serine racemase (SR) is a brain-enriched enzyme that converts L-serine to D-serine. SR interacts with the protein interacting with C-kinase 1 (PICK1), which is known to direct protein kinase C (PKC) to its targets in cells. Here, we investigated whether PKC activity regulates SR activity and D-serine availability in the brain. In vitro, PKC phosphorylated SR and decreased its activity. PKC activation increased SR phosphorylation in serine residues and reduced D-serine levels in astrocyte and neuronal cultures. Conversely, PKC inhibition decreased basal SR phosphorylation and increased cellular D-serine levels. In vivo modulation of PKC activity regulated both SR phosphorylation and D-serine levels in rat frontal cortex. Finally, rats that completed an object recognition task showed decreased SR phosphorylation and increased D-serine/total serine ratios, which was markedly correlated with decreased PKC activity in both cortex and hippocampus. Results indicate that PKC phosphorylates SR in serine residues and regulates D-serine availability in the brain. This interaction may be relevant for the regulation of physiological and pathological mechanisms linked to NMDAR function.

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.

Gliomas are tumors derived from glia or their precursors within the central nervous system. Clinically, gliomas are divided into four grades and the glioblastoma multiforme (GBM), also referred as grade IV astrocytoma, is the most aggressive and the most common glioma in humans. The prognosis for patients with GBM remains dismal, with a median survival of 9-12 months. Despite their striking heterogeneity, common alterations in specific cellular signal transduction pathways occur within most GBMs. Previous work from our group identified the co-chaperone stress-inducible protein 1 (STI1) as a cell surface ligand for cellular prion (PrP(C)), which leads to the activation of several signal transduction pathways, some of which modulate cell survival. In the present work, we used thymidine incorporation assays to investigate the effect of STI1 upon proliferation of the human glioblastoma-derived cell line A172. Here we report that STI1 is secreted by and induces proliferation in tumor cells, an effect that is modulated by the Erk and PI3K pathways, and that, in contrast to glioma cells, STI1 does not induce proliferation of normal glia. In addition, our data suggest the involvement of PrP(C) in STI1-induced proliferation of A172 cells. These results provide initial evidence of a new functional role for STI1 on the physiology of human gliomas, and may lead to the identification of new therapeutic targets in these tumors.

Background The presence, characteristics, and potential clinical relevance of neural progenitor populations within the neural placodes of myelomeningocele patients remain to be studied. Neural stem cells are known to reside adjacent to ependyma-lined surfaces along the central nervous system axis. Objective Given such neuroanatomic correlation and regenerative capacity in fetal development, we assessed myelomeningocele-derived neural placode tissue as a potentially novel source of neural stem and progenitor cells. Methods Nonfunctional neural placode tissue was harvested from infants during the surgical repair of myelomeningocele and subsequently further analyzed by in vitro studies, flow cytometry, and immunofluorescence. To assess lineage potential, neural placode-derived neurospheres were subjected to differential media conditions. Through assessment of platelet-derived growth factor receptor α (PDGFRα) and CD15 cell marker expression, Sox2+Olig2+ putative oligodendrocyte progenitor cells were successfully isolated. Results PDGFRαCD15 cell populations demonstrated the highest rate of self-renewal capacity and multipotency of cell progeny. Immunofluorescence of neural placode-derived neurospheres demonstrated preferential expression of the oligodendrocyte progenitor marker, CNPase, whereas differentiation to neurons and astrocytes was also noted, albeit to a limited degree. Conclusion Neural placode tissue contains multipotent progenitors that are preferentially biased toward oligodendrocyte progenitor cell differentiation and presents a novel source of such cells for use in the treatment of a variety of pediatric and adult neurological disease, including spinal cord injury, multiple sclerosis, and metabolic leukoencephalopathies.

Medulloblastoma (MB) is a malignant brain tumor that originates in the cerebellum in children and spreads via the cerebrospinal fluid to the leptomeningeal spaces of the brain and of the spinal cord. MB is stratified into four distinct groups, according to genetic and clinical features, and patients from group 3 (also known as c-Myc-amplified group) have the highest risk of developing metastatic disease and, consequently, a poor prognosis. Treatment protocols involve surgery, craniospinal radiation, and high-dose chemotherapy, which frequently cause disabling neurotoxic effects in long-term survivors. We used MB cell lines and primary cells isolated from patients from the c-Myc-amplified group to develop a spontaneous spinal metastasis orthotopic xenograft model as a tool to understand the cellular determinants of leptomeningeal and spinal dissemination. Human cells isolated from the primary site tumors expressed 10 fold higher NICD1 (Notch1 Intracellular Domain), the active form of Notch1, than cells isolated from spinal metastatic sites (as quantified by western blot and imunohistochemistry), suggesting the downregulation of canonical Notch1 signaling pathway in MB metastasis. Moreover, flow cytometry analyses revealed that a higher percentage of cells isolated from metastatic sites expressed full-length surface Notch1 as compared to the primary site tumor. These differences cannot be explained by enrichment in the stem cell population at primary tumor sites, as we observed that MB cells isolated from primary tumors and metastatic sites exhibit equivalent self-renewal potential and express equivalent levels of CD133 and CD15. Our goal is to understand the role of notch in regulating medulloblastoma metastasis. Citation Format: Suzana A. Kahn, Sharareh Gholamin, Michael Zhang, Ryan Nitta, Irving Weissman, Siddhartha Mitra, Samuel Cheshier. Involvement of Notch1 signaling pathway in medulloblastoma metastasis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4041. doi:10.1158/1538-7445.AM2014-4041

Interesting selectivities for cancer stem cells versus neuronal stem cells are demonstrated in vitro with analogues of canthin-6-one, an indolic alkaloid isolated from Zanthoxylum chiloperone var. angustifolium (Rutaceae). The implication of the PI3/AKT signalling pathway is also disclosed.