AimsEpilepsy is one of the most common chronic neurological disorders, affecting around 50 million people worldwide, but its underlying cellular and molecular events are not fully understood. The Golgi is a highly dynamic cellular organelle and can be fragmented into ministacks under both physiological and pathological conditions. This phenomenon has also been observed in several neurodegenerative disorders; however, the structure of the Golgi apparatus (GA) in human patients suffering from epilepsy has not been described so far. The aim of this study was to assess the changes in GA architecture in epilepsy.MethodsGolgi visualisation with immunohistochemical staining in the neocortex of adult patients who underwent epilepsy surgery; 3D reconstruction and quantitative morphometric analysis of GA structure in the rat hippocampi upon kainic acid (KA) induced seizures, as well as in vitro studies with the use of Ca2+ chelator BAPTA-AM in primary hippocampal neurons upon activation were performed.ResultsWe observed GA dispersion in neurons of the human neocortex of patients with epilepsy and hippocampal neurons in rats upon KA-induced seizures. The structural changes of GA were reversible, as GA morphology returned to normal within 24 h of KA treatment. KA-induced Golgi fragmentation observed in primary hippocampal neurons cultured in vitro was largely abolished by the addition of BAPTA-AM.ConclusionsIn our study, we have shown for the first time that the neuronal GA is fragmented in the human brain of patients with epilepsy and rat brain upon seizures. We have shown that seizure-induced GA dispersion can be reversible, suggesting that enhanced neuronal activity induces Golgi reorganisation that is involved in aberrant neuronal plasticity processes that underlie epilepsy. Moreover, our results revealed that elevated cytosolic Ca2+ is indispensable for these KA-induced morphological alterations of GA in vitro. The neuronal Golgi apparatus is fragmented in the human brain of patients with epilepsy and rat brain upon seizures. Seizure-induced GA dispersion can be reversible, suggesting that enhanced neuronal activity induces Golgi reorganization that is involved in aberrant neuronal plasticity processes that underlie epilepsy. The driving force behind KA-induced Golgi fragmentation is the elevated cytosolic Ca2+.image

Meningiomas are common intracranial tumors in adults. Abnormal microRNA (miRNA) expression plays a role in their pathogenesis. Change in miRNA expression level can be caused by impaired epigenetic regulation of miRNA-encoding genes. We found the genomic region covering the MIR193B gene to be DNA hypermethylated in meningiomas based on analysis of genome-wide methylation (HumanMethylation450K Illumina arrays). Hypermethylation of MIR193B was also confirmed via bisulfite pyrosequencing. Both hsa-miR-193b-3p and hsa-miR-193b-5p are downregulated in meningiomas. Lower expression of hsa-miR-193b-3p and higher MIR193B methylation was observed in World Health Organization (WHO) grade (G) II/III tumors as compared to GI meningiomas. CCND1 mRNA was identified as a target of hsa-miR-193b-3p as further validated using luciferase reporter assay in IOMM-Lee meningioma cells. IOMM-Lee cells transfected with hsa-miR-193b-3p mimic showed a decreased cyclin D1 level and lower cell viability and proliferation, confirming the suppressive nature of this miRNA. Cyclin D1 protein expression (immunoreactivity) was higher in atypical than in benign meningiomas, accordingly to observations of lower hsa-miR-193b-3p levels in GII tumors. The commonly observed hypermethylation of MIR193B in meningiomas apparently contributes to the downregulation of hsa-miR-193b-3p. Since hsa-miR-193b-3p regulates proliferation of meningioma cells through negative regulation of cyclin D1 expression, it seems to be an important tumor suppressor in meningiomas.

BCOR is expressed in a new brain tumour entity, i.e. 'CNS tumour with BCOR internal tandem duplication' (HGNET BCOR) but not in several other high grade paediatric brain tumours investigated. Immunohistochemical detection of BCOR expression may therefore serve as a potential diagnostic marker. Nevertheless, in rare paediatric glioma cases recurrent EP300BCOR fusions were detected, which resulted in strong BCOR immunopositivity. We have therefore examined other, not analysed so far, types of central nervous system (CNS) tumours, pineoblastoma and germinoma, to assess a potential involvement of BCOR in these tumours. Levels of BCOR RNA expression were investigated by NanoString nCounter system analysis in a series of altogether 66 high grade paediatric tumours, including four pineoblastoma cases. Immunohistological detection of BCOR was performed in eight pineoblastoma, five germinoma and four atypical teratoid rhabdoid tumours (ATRTs), all located in the pineal region. We detected BCOR expression in all pineoblastomas, at the RNA and protein levels, but not in germinomas and ATRTs. Further analysis of pineoblastoma samples did not reveal the presence of either BCOR internal tandem duplication or BCOR fusion involvement. Positive immunohistological BCOR nuclear reaction in pineoblastoma may therefore differentiate this type of tumour from other high grade tumours located in the pineal region.

ObjectivesWe investigated the involvement of the proteasome in the mechanism of preconditioning with hyperbaric oxygen (HBO-PC). MethodsThe experiments were performed on male Wistar rats subjected to a transient global cerebral ischemia of 5 min duration (2-vessel occlusion model) and preconditioned or not with HBO for 5 preceding days (1 h HBO at 2.5 atmosphere absolute [ATA] daily). In subgroups of preconditioned rats, the proteasome inhibitor MG132 was administered 30 min prior to each preconditioning session. Twenty-four hours and 7 days post-ischemia, after neurobehavioral assessment, the brains were collected and evaluated for morphological changes and quantitative immunohistochemistry of cell markers and apoptosis-related proteins. ResultsWe observed reduced damage of CA1 pyramidal cells in the HBO preconditioned group only at 7 days post-ischemia. However, both at early (24 h) and later (7 days) time points, HBO-PC enhanced the tissue expression of 20S core particle of the proteasome and of the nestin, diminished astroglial reactivity, and reduced p53, rabbit anti-p53 upregulated modulator of apoptosis (PUMA), and rabbit anti-B cell lymphoma-2 interacting mediator of cell death (Bim) expressions in the hippocampus and cerebral cortex. HBO-PC also improved T-maze performance at 7 days. Proteasome inhibitor abolished the beneficial effects of HBO-PC on post-ischemic neuronal injury and functional impairment and reduced the ischemic alterations in the expression of investigated proteins. SignificancePreconditioning with hyperbaric oxygen-induced brain protection against severe ischemic brain insult appears to involve the proteasome, which can be linked to a depletion of apoptotic proteins and improved regenerative potential.

Intratumoral hemorrhage (ITH) as a variant of intracranial hemorrhage (ICH) is a known, albeit rare, clinical entity. Hemorrhages within brain neoplasms seem to remain underreported, including angiomatous meningioma and pilocytic astrocytoma as well as sarcoma spread to CNS in pediatric cases. Neuropathological studies remain a valuable part of ITH assessment. New experimental therapies for brain tumors, including combinations with hyperbaric oxygen or treatment with kinase inhibitors need to be evaluated for their effect on brain tumor vascularization. A growing body of scientific evidence points towards the need to strengthen the significance of vascular component in brain tumor classification.

Abstract The majority of supratentorial ependymomas in children contain oncogenic fusions, such as ZFTA–RELA or YAP1‐MAMLD1. In contrast, posterior fossa (PF) ependymomas lack recurrent somatic mutations and are classified based on gene expression or methylation profiling into group A (PFA) and group B (PFB). We have applied a novel method, NanoString nCounter Technology, to identify four molecular groups among 16 supratentorial and 50 PF paediatric ependymomas, using 4–5 group‐specific signature genes. Clustering analysis of 16 supratentorial ependymomas revealed 9 tumours with a RELA fusion‐positive signature (RELA+), 1 tumour with a YAP1 fusion‐positive signature (YAP1+), and 6 not‐classified tumours. Additionally, we identified one RELA+ tumour among historically diagnosed CNS primitive neuroectodermal tumour samples. Overall, 9 of 10 tumours with the RELA+ signature possessed the ZFTA‐RELA fusion as detected by next‐generation sequencing (p = 0.005). Similarly, the only tumour with a YAP1+ signature exhibited the YAP1‐MAMLD1 fusion. Among the remaining unclassified ependymomas, which did not exhibit the ZFTA‐RELA fusion, the ZFTA‐MAML2 fusion was detected in one case. Notably, among nine ependymoma patients with the RELA+ signature, eight survived at least 5 years after diagnosis. Clustering analysis of PF tumours revealed 42 samples with PFA signatures and 7 samples with PFB signatures. Clinical characteristics of patients with PFA and PFB ependymomas corroborated the previous findings. In conclusion, we confirm here that the NanoString method is a useful single tool for the diagnosis of all four main molecular groups of ependymoma. The differences in reported survival rates warrant further clinical investigation of patients with the ZFTA‐RELA fusion.

INTRODUCTION:The co-existence of two independent brain tumors at the same anatomical site is rare and occurs as a "collision tumor" or "tumor-to-tumor metastasis." In intracranial location, meningioma is the most common neoplasm in such coincidences.CASE DESCRIPTION:We present a case involving a 31-year-old woman with a complex tumor consisting of chordoma and meningioma in the petroclival region. The patient presented with left facial numbness, ataxia, and left-sided hemiparesis. Computed tomography and magnetic resonance imaging showed a well-demarcated, intradural, extra-axial tumor mass in the petroclival region. After complete total resection, histopathological examination revealed two different parts of the tumor, consisting of chordoma and meningioma. Therefore, additional radiation therapy and adjuvant chemotherapy were given.DISCUSSION:To the best of our knowledge, this is the first description of the simultaneous occurrence of chordoma and meningioma in the same anatomical location. In such a scenario, differential diagnosis of choroid meningioma and chordoma is required. The correct recognition of both components is important for treating this complex tumor, and its separate elements may require independent approaches.

The triple-negative breast cancer (TNBC) is the most malignant among breast cancers and has the high risk of developing metastasis into the brain. Metastases of breast cancers are increasing and pose a clinical challenge as the current treatments are not effective due to the unique brain microenvironment for metastatic breast cancer cells. While the contribution of brain macrophages to the formation of the metastatic niche is established, factors responsible for the crosstalk between cells remain elusive. SPP1 encoding a secreted phosphoprotein 1 (ostepontin) is highly overexpressed in malignant breast cancers. We evaluated the role of SPP1 in invasion and metastasis of human breast cancer cells. We found the increased invasion of triple-negative MDA-MB-231 (MDA-231) cells in the presence of human microglial HMSV40 cells. Using Western blot analysis demonstrated the elevated levels of focal adhesion kinase (FAK) and signal transducer and activator of transcription 3 (STAT3) in MDA-231 cells in co-cultures. Moreover, blocking SPP1 and integrin interactions with the synthetic RGD peptide, efficiently diminished both basic and microglia-induced invasion of MDA-231. To assess the role of SPP1 in cell invasion, we established the MDA-231 cells with knocked-down SPP1 expression using shRNA (shSPP1). Interestingly, the shSPP1 cells were unresponsive towards HMSV40 microglia. We have previously found that an antibiotic minocycline reduces SPP1 expression in glioma cells. We performed cell toxicity studies on 4 breast cancer cell lines and various non-malignant cells. All tested malignant cancer cells were more sensitize to minocycline than non-cancerous cells and breast cancer cells derived from TNBC were the most susceptible. Altogether, we demonstrate that microglia support invasion of breast cancer cells via SPP1/osteopontin triggering the integrin signalling, and minocycline by downregulating SPP1 expression may reduce both basic and microglia-induced cancer invasion. Therefore, we purpose that minocycline could be a new therapeutics targeting metastatic brain cancers.

Long non-coding RNAs (lncRNAs) have critical functions in tumorigenesis and progression of colorectal cancer (CRC). The role of lncRNA COL4A2-AS1 (COL4A2-AS1) lacks system investigation. The current study comprehensively analyzed the expression, biological functions, and mechanism of COL4A2-AS1 in CRC through performing real-time quantitative PCR (RT-qPCR), Western blot, cell transfection, cell colony assay, MTT assay, flow cytometry and dual-luciferase reporter system assays. A xenograft model of CRC was constructed to further verify the function of COL4A2-AS1 in CRC progression in vivo. The data revealed an upregulated expression of COL4A2-AS1 in CRC tissues and cell lines than paired adjacent tissues and normal cell line. Silencing COL4A2-AS1 inhibited proliferation, aerobic glycolysis, and promoted apoptosis of CRC cells in vivo and in vitro. However, overexpression of COL4A2-AS1 significantly promoted CRC cell proliferation and aerobic glycolysis. In CRC cells, miR-20b-5p was sponged by COL4A2-AS1 and hypoxia-inducible factor 1 alpha subunit (HIF1A). Restoration of HIF1A expression reversed the inhibitory effects of silencing COL4A2-AS1 on aerobic glycolysis and proliferation of CRC cells. The current findings showed that COL4A2-AS1 promoted the proliferation, and aerobic glycolysis of CRC cells potentially through modulating the miR-20b-5p/HIF1A axis.

Herpes simplex encephalomyelitis (HSE) is a rare disease with a high mortality rate. Correct diagnosis is established on the basis of the combination of the clinical and investigative features. Unfortunately, precise diagnosis remains difficult due to several clinical similarities and false negative or inconclusive results of diagnostic tests. Here, we present two cases of HSE together with the morphological and ultrastructural picture. The first case was a 45-year-old man with acute symptoms of encephalitis, and the other one was a 28-year-old woman presenting subacute encephalomyelitis. Both cases had negative serologic and molecular results for Herpes simplex in the blood and cerebrospinal fluid. Brain and spinal cord samples taken from both cases were stained typically with histological and immunohistochemical methods and small tissue fragments were examined with the transmission electron microscope (TEM). Microscopic examination confirmed viral encephalomyelitis in both cases. An electron micrograph showed typical intranuclear viral particles inside of damaged neurons, which together with topography of brain and spinal cord changes suggest HHV-1/HHV-2 in the first case and/or HHV-3 in the other case. Thus, morphological and ultrastructural examinations may be a useful tool to set up correct diagnosis and help to determine the pathogenic factor in patients suspected of viral encephalomyelitis.

Four molecular types of rare central nervous system (CNS) tumors have been recently identified by gene methylation profiling: CNS Neuroblastoma withFOXR2activation (CNS NB-FOXR2), CNS Ewing Sarcoma Family Tumor withCICalteration (CNS EFT-CIC), CNS high grade neuroepithelial tumor withMN1alteration (CNS HGNET-MN1) and CNS high grade neuroepithelial tumor withBCORalteration (CNS HGNET-BCOR). Although they are not represented in 2016 updated WHO classification of CNS tumors, their diagnostic recognition is important because of clinical consequences. We have introduced a diagnostic method based on transcription profiling of tumor specific signature genes from formalin-fixed, paraffin-embedded tumor blocks using NanoString nCounter Technology. Altogether, 14 out of 187 (7.4%) high grade pediatric brain tumors were diagnosed with either of four new CNS categories. Histopathological examination of the tumors confirmed, that they demonstrate a spectrum of morphology mimicking other CNS high grade tumors. However, they also exhibit some suggestive histopathological and immunohistochemical features that allow for a presumptive diagnosis prior to molecular assessment. Clinical characteristics of patients corroborated with the previous findings for CNS EFT-CIC, CNS NB-FOXR2 and CNS HGNET-MN1 patients, with a favorable survival rate for the latter two groups. Among six CNS HGNET-BCOR patients, three patients are long term survivors, suggesting possible heterogeneity within this molecular category of tumors. In summary, we confirmed the effectiveness of NanoString method using a single, multi-gene tumor specific signature and recommend this novel approach for identification of either one of the four newly described CNS tumor entities.

Intracranial bleeding occurs in a substantial percentage of patients with neurotrauma and may gravely impact clinical outcomes. Hyperbaric oxygen (HBO) has been tested for traumatic brain injury (TBI), however its effect on the hemorrhagic component of TBI remains poorly understood. The characteristics of intracranial bleeding vary in different animal models of TBI. HBO appears to combat vascular injury and to reduce hemorrhagic complications. While the number of studies is limited, a decrease in intracranial bleeding and protection from BBB destruction may determine the effectiveness of HBO in TBI. Based on the results of experimental and clinical studies, this review advocates that intracranial bleeding in the course of TBI is the indispensable aspect of outcome assessment and postulate the search for new markers of traumatic vascular injury responsive to oxygen treatment.

Abstract Brain metastasis from different cancers, including lung, breast, melanoma, colorectal or renal cell carcinoma is relatively common and its frequency increases with a prolonged survival of cancer patients. New anti-cancer therapies frequently fail to reduce metastatic burden. While the important role of tumor-associated macrophages as pro-tumorigenic cells facilitating tissue remodeling, invasion and metastasis is well documented, much less is known about the immune microenvironment of brain metastases and potential mechanisms that mediate interactions of cancer cells with brain immune cells - microglia. Triple-negative breast cancer metastases to the brain were discovered in 46% of patients. We evaluated the abundance and morphology of microglia on sections from breast cancer metastases using immunohistochemistry. We found that microglia cells are activated, surround the breast tumor cells and do not infiltrate the solid tumor. Searching for a potential attractant of microglia, we determined osteopontin levels in six human breast cancer cell lines and found upregulation of osteopontin in transformed cells, with the highest level in the triple-negative MDA-MB-231 cells. MDA-MB-231 cells activated primary murine microglia cultures when co-cultured. Invasion of MDA-MB-231 cells in co-cultures with murine immortalized BV2 microglial cells and human SV40 immortalized microglia was increased, as demonstrated using Matrigel Invasion Assay. Using immunofluorescence we detected osteopontin in cancer cells in human breast cancer metastases. Moreover, we found that minocycline, a clinically used antibiotic, reduces the osteopontin production in human breast cancer cells and the most sensitive cells were MDA-MB-231 cells. Our study shows that metastatic cancer cells may employ microglia to facilitate extravasation and colonization of brain parenchyma. We postulate that osteopontin mediates interactions between microglia and metastatic cancer cells and minocycline may interfere with those interactions. Funding: TEAM TECH CORE FACILITY FNP: Development of comprehensive diagnostics and personalized therapy in neuro-oncology

Glioblastoma (GBM) is the most aggressive glial neoplasm characterized by infiltrative cell growth in adults. The current standard of care for high-grade glioma patients includes surgery, radiotherapy and chemotherapy using temozolomide and other alkylating agents. Despite this, median survival of the patients with GBM is less than two years. One of the main factors related to the progression of neoplastic cells is hyperactivity of protein kinases, including CK2 kinase and a high level of tumor hypoxia, both of which also contribute to tumour resistance to treatment. Our previous study indicated that some CK2 inhibitors exhibit anti-proliferative effect on glioma cells. The aim of this study was to examine whether HBO may enhance the anti-tumour efficacy of 1-(β-D-2’-deoxyribofuranosyl)-4,5,6,7-tetrabromo-1H-benzimidazole (TDB) - CK2 inhibitor, under combination HBO/TDB therapy. Studies were performed on human glioblastoma T98G cell line (ATCC). Cells were cultured in MEM medium supplemented with 1-(β-D-2’-deoxyribofuranosyl)-4,5,6,7-tetrabromo-1H-benzimidazole in concentrations of 0.1 μM; 1 μM, 25 μM, 50 μM, 75μM, 100 μM. Cultures were sustained in various oxygen conditions: normoxia for 24 and 48 hours or1 hour of hyperbaric oxygen (HBO, 97,5% O2/2,5% CO2, pressure of 2 ATA) followed by 23 hours of normoxia (21% O2/5% CO2/78% N2). Control groups included the cultures sustained in normoxia conditions. The viability of glioma cell lines was established at 24 and 48 hours post TDB treatment by Cell Titer 96®A Queous One Solution Cell Proliferation Assay. The study evidenced that TDB inhibited the viability of neoplastic cells at a concentration of 75 μM after 24 and 48 hours. Administration of hyperbaric oxygen alone also caused a reduction in viability of glioblastoma cells. The cytotoxic effect of the tested CK2 inhibitor was significantly enhanced when tested compound was combined with HBO. What’s more, under the influence of hyperbaric oxygen, TDB significantly reduced the viability of tumor cells already at a concentration of 25 μM after 24 hours. Hyperbaric oxygen administration significantly reduces the viability of T98G line cells and increases their sensitivity to the tested CK2 kinase inhibitor. The beneficial cytotoxic effect of TDB/HBO can be obtained at lower concentrations of the tested compound and after shorter exposure time as compared to its administration without HBO. Acknowledgement: The research was supported by the Foundation for the Development of Diagnostic and Therapy, Warsaw

Abstract BACKGROUND Spinal cord tumours in children include ependymal and other tumours of glial origin, all of them displaying GFAP marker. Some tumours may present difficulties in histopathological diagnosis e.g. due to intratumour heterogeneity. Therefore, molecular approach should be examined for its diagnostic usefulness. We investigated a series of originally diagnosed spinal cord ependymal tumours, using transcriptional profiling, to confirm if molecular classification is compatible with histopathological diagnosis. MATERIAL AND METHODS Overall, 9 patients diagnosed between 2001 and 2014 in The Children’s Memorial Health Institute (CMHI) in Warsaw, Poland, were included in the analysis. 4 patients were diagnosed with GI myxopapillary ependymomas, 3 patients with GII and 2 patients with GIII grade ependymal tumours. Total RNA was extracted from FFPE tumour samples using RNeasy kits (Qiagen). Transcriptional profiling was performed using NanoString nCounter system analysis. Tumours were analysed according to the manufacturer’s procedures for hybridization, detection and scanning. Raw counts for each gene underwent technical and biological normalization using nSolver software. A custom NanoString CodeSet consisted of 8 marker genes: GFAP as a glial marker, CAPS and FAM81B as the markers for ependymal tumours and OLIG1, OLIG2, PMP2, KLRC3 and C1orf61 as the markers for other gliomas. Marker genes were identified by re-analysis of publically available microarrays data from childhood brain tumour samples. Histopathological reassessment of tumour preparations was performed by two experienced neuropathologists. RESULTS Hierarchical clustering of 9 samples revealed that two tumours clustered separately and displayed low expression of ependymal markers but high expression of all other glioma markers. Subsequent histopathological re-analysis of preparation of the later 2 tumours showed that one of them displayed features of pilocytic astrocytoma with loose, microcytic and fibrillary areas accompanied by advanced myxoid degenerative changes mimicking the picture of myxopapillary ependymoma. The second tumour revealed heterogeneous morphology with areas of diffuse low grade astrocytoma, pilocytic astrocytoma and fragments displaying ependymal features, including angiocentric pattern with ependymoma-like perivascular arrangement of neoplastic cells. CONCLUSION The results of analysis indicate that RNA expression profiling from FFPE tumour samples using NanoString nCounter system may be a useful approach in differentiation of ependymal tumours from other glial tumours with misleading morphology located in the spinal cord in children. Funded by the National Science Centre, Poland (2016/21/B/NZ2/01785 and 2016/23/B/NZ2/03064).

Background Lung, breast, melanoma, colorectal or renal carcinoma cells frequently metastasize to the central nervous system (CNS) and the frequency of CNS metastases increases with a prolonged survival of cancer patients. New anti-cancer therapies frequently fail to reduce metastatic burden. Tumor-associated macrophages act as pro-tumorigenic cells facilitating tissue remodeling, invasion and metastasis. The CNS is equipped in resident macrophages, including microglia, perivascular, meningeal and choroid plexus macrophages, that may interact with metastatic cancer cells and create a permissive niche in the CNS. The literature review shows accumulation of activated microglia in different cancer metastases. Methods We evaluated systematically the abundance and morphology of microglia and other macrophages on tissue microarrays and sections from breast cancer metastases using immunohistochemistry. Searching for a potential attractant of microglia, we evaluated the expression of Osteopontin (OPN) on sections from breast cancer metastases and the protein levels in six human breast cancer cell lines. The responses of microglial cultures to breast cancer MDA-MB-231 cells were characterized. Invasion of breast cancer cells in co-cultures with microglial cells was evaluated using a Matrigel assay. Results We found activated, amoeboid microglia in tissues surrounding breast cancer CNS metastases. OPN was expressed mainly by metastatic breast cancer cells and its high expression was also noted in CNS metastases from different cancers. Invasiveness of MDA-MB-231 cells co-cultured with murine or human microglial cells was significantly increased. OPN was produced by human breast cancer cells, but not by non-transformed cells. Its expression was blocked by minocycline, a clinically used antibiotic. Conclusion Our study shows that metastatic cancer cells may employ microglia to facilitate colonization of brain parenchyma. OPN production is elevated in cultured breast cancer cells and CNS breast cancer metastases. OPN can mediate interactions between microglia and metastatic cancer cells. Minocycline interferes with those interactions and may impair creating a metastatic niche and cancer progression. Legal entity responsible for the study Nencki Institute of Experimental Biology. Funding Foundation for Polish Science Team Tech Core Facility: Development of comprehensive diagnostics and personalized therapy in neuro-oncology. Disclosure All authors have declared no conflicts of interest.

Tumours of astroglial origin, both malignant glioblastoma (GBM) and benign subependymal giant cell astrocytoma (SEGA), pose a serious medical problem. Casein kinase 2 (CK2), a member of the serine/threonine kinase family, has antiapoptotic properties and plays a vital role in glial tumour cell survival. It contributes to invasive cell growth and is often upregulated in malignant neoplastic cells; however, its role in benign tumours of astrocytic origin is less understood. In the present study we investigated the effects of small molecule CK2 inhibitors on proliferation and viability of glioma cells in vitro. The experiments were conducted on commercial T98G malignant glioma cell line and the SEGA cell line, derived from a paediatric case of tuberous sclerosis complex (TSC). Cell cultures were incubated with selected CK2 inhibitors: 4,5,6,7-tetrabromo-1H-benzimidazole (TBI), 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole (DMAT) and 4,5,6,7-tetrabromo-1H-benzotriazole (TBB) at 0.1, 1, 10, 25, 50, 75 and 100 µM concentrations for 24 and 48 hours. Cell proliferation was assessed using a cell counter and cell viability was evaluated by MTT assay. TBB at 75 µM and 100 µM, and TBI starting from 25 µM, both reduced T98G cell proliferation after 24 hours, while DMAT was ineffective. All tested small molecule CK2 inhibitors appear to reduce T98G cell growth and viability after 48 hours, although TBI appeared to be the most effective and reduced cell growth in the 50-100 µM dose range. TBI also showed potential efficacy in reducing the number and viability of SEGA cells after 48 hours. Proliferation and viability of SEGA cells have proven resistant to TBB treatment. DMAT only reduced the viability of SEGA cells at 24 (at 100 µM) and 48 hours (10-100 µM). Importantly, normal human astrocyte cells were found to be moderately resistant to TBB, while their viability was mildly reduced at higher doses of DMAT and TBI. In conclusion, CK2 appears to play a role not only in malignant glioma cells but it can also sustain the viability and proliferation of benign astrocytoma cells. The obtained antitumor effects of CK2 inhibitors significantly exceeded their mild or no effect on normal astrocytes in control, which supports the therapeutic potential of these compounds against gliomas.

Glioblastoma (GBM) is the most common primary brain tumor. Tumor hypoxia is a pivotal factor responsible for the progression of this malignant glioma, and its resistance to radiation and chemotherapy. Thus, improved tumor tissue oxygenation may promote greater sensitivity to anticancer treatment. Protein kinase D1 (PKD1) protects cells from oxidative stress, and its abnormal activity serves an important role in multiple malignancies. The present study examined the effects of various oxygen conditions on the cytotoxic potential of the novel isothiourea derivate N,N'‑dimethyl‑S‑(2,3,4,5,6‑pentabromobenzyl)‑​isothiouronium bromide (ZKK‑3) against the T98G GBM cell line. ZKK‑3 was applied at concentrations of 10, 25 and 50 µM, and cells were maintained under conditions of normoxia, anoxia, hypoxia, hyperbaric oxygen (HBO), hypoxia/hypoxia and hypoxia/HBO. The proliferation and viability of neoplastic cells, and protein expression levels of hypoxia‑inducible factor 1α (HIF‑1α), PKD1, phosphorylated (p)PKD1 (Ser 916) and pPKD1 (Ser 744/748) kinases were evaluated. Oxygen deficiency, particularly regarding hypoxia, could diminish the cytotoxic effect of ZKK‑3 at 25 and 50 µM and improve T98G cell survival compared with normoxia. HBO significantly reduced cell proliferation and increased T98G cell sensitivity to ZKK‑3 when compared with normoxia. HIF‑1α expression levels were increased under hypoxia compared with normoxia and decreased under HBO compared with hypoxia/hypoxia at 0, 10 and 50 µM ZKK‑3, suggesting that HBO improved oxygenation of the cells. ZKK‑3 exhibited inhibitory activity against pPKD1 (Ser 916) kinase; however, the examined oxygen conditions did not appear to significantly influence the expression of this phosphorylated form in cells treated with the tested compound. Regarding pPKD1 (Ser 744/748), a significant difference in expression was observed only for cells treated with 10 µM ZKK‑3 and hypoxia/hypoxia compared with normoxia. However, there were significant differences in the expression levels of both phosphorylated forms of PKD1 under different oxygen conditions in the controls. In conclusion, the combination of isothiourea derivatives and hyperbaric oxygenation appears to be a promising therapeutic approach for malignant glioma treatment.