A H3K27M-targeted vaccine in adults with diffuse midline glioma.

Substitution of lysine 27 to methionine in histone H3 (H3K27M) defines an aggressive subtype of diffuse glioma. Previous studies have shown that a H3K27M-specific long peptide vaccine (H3K27M-vac) induces mutation-specific immune responses that control H3K27M+ tumors in major histocompatibility complex-humanized mice. Here we describe a first-in-human treatment with H3K27M-vac of eight adult patients with progressive H3K27M+ diffuse midline glioma on a compassionate use basis. Five patients received H3K27M-vac combined with anti-PD-1 treatment based on physician's discretion. Repeat vaccinations with H3K27M-vac were safe and induced CD4+ T cell-dominated, mutation-specific immune responses in five of eight patients across multiple human leukocyte antigen types. Median progression-free survival after vaccination was 6.2 months and median overall survival was 12.8 months. One patient with a strong mutation-specific T cell response after H3K27M-vac showed pseudoprogression followed by sustained complete remission for >31 months. Our data demonstrate safety and immunogenicity of H3K27M-vac in patients with progressive H3K27M+ diffuse midline glioma.

Protoporphyrin IX (PpIX) Fluorescence during Meningioma Surgery: Correlations with Histological Findings and Expression of Heme Pathway Molecules.

Background: The usefulness of 5-ALA-mediated fluorescence-guided resection (FGR) in meningiomas is controversial, and information on the molecular background of fluorescence is sparse. Methods: Specimens obtained during 44 FGRs of intracranial meningiomas were analyzed for the presence of tumor tissue and fluorescence. Protein/mRNA expression of key transmembrane transporters/enzymes involved in PpIX metabolism (ABCB6, ABCG2, FECH, CPOX) were investigated using immunohistochemistry/qPCR. Results: Intraoperative fluorescence was observed in 70 of 111 specimens (63%). No correlation was found between fluorescence and the WHO grade (p = 0.403). FGR enabled the identification of neoplastic tissue (sensitivity 84%, specificity 67%, positive and negative predictive value of 86% and 63%, respectively, AUC: 0.75, p < 0.001), and was improved in subgroup analyses excluding dura specimens (86%, 88%, 96%, 63% and 0.87, respectively; p < 0.001). No correlation was found between cortical fluorescence and tumor invasion (p = 0.351). Protein expression of ABCB6, ABCG2, FECH and CPOX was found in meningioma tissue and was correlated with fluorescence (p < 0.05, each), whereas this was not confirmed for mRNA expression. Aberrant expression was observed in the CNS. Conclusion: FGR enables the intraoperative identification of meningioma tissue with limitations concerning dura invasion and due to ectopic expression in the CNS. ABCB6, ABCG2, FECH and CPOX are expressed in meningioma tissue and are related to fluorescence.

Intratumor heterogeneity and T cell exhaustion in primary CNS lymphoma.

BACKGROUND: Primary central nervous system lymphoma (PCNSL) is a rare lymphoma of the central nervous system, usually of diffuse large B cell phenotype. Stereotactic biopsy followed by histopathology is the diagnostic standard. However, limited material is available from CNS biopsies, thus impeding an in-depth characterization of PCNSL. METHODS: We performed flow cytometry, single-cell RNA sequencing, and B cell receptor sequencing of PCNSL cells released from biopsy material, blood, and cerebrospinal fluid (CSF), and spatial transcriptomics of biopsy samples. RESULTS: PCNSL-released cells were predominantly activated CD19+CD20+CD38+CD27+ B cells. In single-cell RNA sequencing, PCNSL cells were transcriptionally heterogeneous, forming multiple malignant B cell clusters. Hyperexpanded B cell clones were shared between biopsy- and CSF- but not blood-derived cells. T cells in the tumor microenvironment upregulated immune checkpoint molecules, thereby recognizing immune evasion signals from PCNSL cells. Spatial transcriptomics revealed heterogeneous spatial organization of malignant B cell clusters, mirroring their transcriptional heterogeneity across patients, and pronounced expression of T cell exhaustion markers, co-localizing with a highly malignant B cell cluster. CONCLUSIONS: Malignant B cells in PCNSL show transcriptional and spatial intratumor heterogeneity. T cell exhaustion is frequent in the PCNSL microenvironment, co-localizes with malignant cells, and highlights the potential of personalized treatments.

In Vivo Quantitative Imaging of Glioma Heterogeneity Employing Positron Emission Tomography.

Glioblastoma is the most common primary brain tumor, highly aggressive by being proliferative, neovascularized and invasive, heavily infiltrated by immunosuppressive glioma-associated myeloid cells (GAMs), including glioma-associated microglia/macrophages (GAMM) and myeloid-derived suppressor cells (MDSCs). Quantifying GAMs by molecular imaging could support patient selection for GAMs-targeting immunotherapy, drug target engagement and further assessment of clinical response. Magnetic resonance imaging (MRI) and amino acid positron emission tomography (PET) are clinically established imaging methods informing on tumor size, localization and secondary phenomena but remain quite limited in defining tumor heterogeneity, a key feature of glioma resistance mechanisms. The combination of different imaging modalities improved the in vivo characterization of the tumor mass by defining functionally distinct tissues probably linked to tumor regression, progression and infiltration. In-depth image validation on tracer specificity, biological function and quantification is critical for clinical decision making. The current review provides a comprehensive overview of the relevant experimental and clinical data concerning the spatiotemporal relationship between tumor cells and GAMs using PET imaging, with a special interest in the combination of amino acid and translocator protein (TSPO) PET imaging to define heterogeneity and as therapy readouts.

Blockade of inhibitory killer cell immunoglobulin-like receptors and IL-2 triggering reverses the functional hypoactivity of tumor-derived NK-cells in glioblastomas.

Killer cell immunoglobulin-like receptors (KIRs) comprise a group of highly polymorphic inhibitory receptors which are specific for classical HLA class-I molecules. Peripheral blood and freshly prepared tumor cell suspensions (n = 60) as well as control samples (n = 32) were investigated for the distribution, phenotype, and functional relevance of CD158ab/KIR2DL1,-2/3 expressing NK-cells in glioblastoma (GBM) patients. We found that GBM were scarcely infiltrated by NK-cells that preferentially expressed CD158ab/KIR2DL1,-2/3 as inhibitory receptors, displayed reduced levels of the activating receptors CD335/NKp46, CD226/DNAM-1, CD159c/NKG2C, and showed diminished capacity to produce IFN-γ and perforin. Functional hypoactivity of GBM-derived NK-cells persisted despite IL-2 preactivation. Blockade with a specific KIR2DL-1,2/3 monoclonal antibody reversed NK-cell inhibition and significantly enhanced degranulation and IFN-γ production of IL-2 preactivated NK-cells in the presence of primary GBM cells and HLA-C expressing but not HLA class-I deficient K562 cells. Additional analysis revealed that significant amounts of IL-2 could be produced by tumor-derived CD4+ and CD8+CD45RA- memory T-cells after combined anti-CD3/anti-CD28 stimulation. Our data indicate that both blockade of inhibitory KIR and IL-2 triggering of tumor-derived NK-cells are necessary to enhance NK-cell responsiveness in GBM.

Interrogating Glioma-Associated Microglia and Macrophage Dynamics Under CSF-1R Therapy with Multitracer In Vivo PET/MRI.

Glioma-associated microglia and macrophages (GAMMs) are key players in creating an immunosuppressive microenvironment. They can be efficiently targeted by inhibiting the colony-stimulating factor 1 receptor (CSF-1R). We applied noninvasive PET/CT and PET/MRI using 18F-fluoroethyltyrosine (18F-FET) (amino acid metabolism) and N,N-diethyl-2-[4-(2-18F-fluoroethoxy)phenyl]-5,7-dimethylpyrazolo[1,5-a]pyrimidine-3-acetamide (18F-DPA-714) (translocator protein) to understand the role of GAMMs in glioma initiation, monitor in vivo therapy-induced GAMM depletion, and observe GAMM repopulation after drug withdrawal. Methods: C57BL/6 mice (n = 44) orthotopically implanted with syngeneic mouse GL261 glioma cells were treated with different regimens using the CSF-1R inhibitor PLX5622 (6-fluoro-N-((5-fluoro-2-methoxypyridin-3-yl)methyl)-5-((5-methyl-1H-pyrrolo[2,3-b]pyridin-3-yl)methyl)pyridin-2-amine) or vehicle, establishing a preconditioning model and a repopulation model, respectively. The mice underwent longitudinal PET/CT and PET/MRI. Results: The preconditioning model indicated similar tumor growth based on MRI (44.5% ± 24.8%), 18F-FET PET (18.3% ± 11.3%), and 18F-DPA-714 PET (16% ± 19.04%) volume dynamics in all groups, suggesting that GAMMs are not involved in glioma initiation. The repopulation model showed significantly reduced 18F-DPA-714 uptake (-45.6% ± 18.4%), significantly reduced GAMM infiltration even after repopulation, and a significantly decreased tumor volume (-54.29% ± 8.6%) with repopulation as measured by MRI, supported by a significant reduction in 18F-FET uptake (-50.2% ± 5.3%). Conclusion: 18F-FET and 18F-DPA-714 PET/MRI allow noninvasive assessment of glioma growth under various regimens of CSF-1R therapy. CSF-1R-mediated modulation of GAMMs may be of high interest as therapy or cotherapy against glioma.

The Colony Stimulating Factor-1 Receptor (CSF-1R)-Mediated Regulation of Microglia/Macrophages as a Target for Neurological Disorders (Glioma, Stroke).

Immunomodulatory therapies have fueled interest in targeting microglial cells as part of the innate immune response after infection or injury. In this context, the colony-stimulating factor 1 (CSF-1) and its receptor (CSF-1R) have gained attention in various neurological conditions to deplete and reprogram the microglia/macrophages compartment. Published data in physiological conditions support the use of small-molecule inhibitors to study microglia/macrophages dynamics under inflammatory conditions and as a therapeutic strategy in pathologies where those cells support disease progression. However, preclinical and clinical data highlighted that the complexity of the spatiotemporal inflammatory response could limit their efficiency due to compensatory mechanisms, ultimately leading to therapy resistance. We review the current state-of-art in the field of CSF-1R inhibition in glioma and stroke and provide an overview of the fundamentals, ongoing research, potential developments of this promising therapeutic strategy and further application toward molecular imaging.

Diagnostic impact of additional O-(2-[18F]fluoroethyl)-L-tyrosine (18F-FET) PET following immunotherapy with dendritic cell vaccination in glioblastoma patients.

OBJECTIVE: Vaccination therapy using tumour antigen-loaded, autologous dendritic cells (DC) is a promising therapeutic approach alongside standard treatment for glioblastoma (GBM). However, reliable diagnostic criteria regarding therapy monitoring are not established. Here, we analysed the impact of additional 18F-fluoroethyl-tyrosine positron emission tomography (18F-FET PET) imaging following DC vaccination therapy. METHODS: We analysed data of GBM patients who received DC vaccination therapy. Following MRI diagnosis of tumour recurrence, additional static and dynamic 18F-FET PET imaging was performed. Vaccination was performed five times by intradermal injections, either weekly between concomitant radio/-chemotherapy and intermittent chemotherapy or after tumour recurrence, before re-radiation therapy. MRI and 18F-FET PET results were compared and correlated with clinical data. RESULTS: Between 2003 and 2016, 5 patients were identified who received DC vaccination and 18F-FET PET imaging (1 female/4 males; mean age: 44 ± 14 y). 3/5 patients showed congruent results of tumour progression. In three patients 18F-FET PET indicated treatment related changes, which was in contrast to MRI findings that indicated tumour progression. In these patients 18F-FET PET results could be confirmed by either neuropathological diagnosis or according to the RANO criteria. CONCLUSIONS: Despite the small patients number our results indicate an additional impact of 18F-FET PET for monitoring outcome following vaccination therapy.

TSPO imaging-guided characterization of the immunosuppressive myeloid tumor microenvironment in patients with malignant glioma.

BACKGROUND: Tumor-associated microglia and macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) are potent immunosuppressors in the glioma tumor microenvironment (TME). Their infiltration is associated with tumor grade, progression, and therapy resistance. Specific tools for image-guided analysis of spatiotemporal changes in the immunosuppressive myeloid tumor compartments are missing. We aimed (i) to evaluate the role of fluorodeoxyglucose (18F)DPA-714* (translocator protein [TSPO]) PET-MRI in the assessment of the immunosuppressive TME in glioma patients, and (ii) to cross-correlate imaging findings with in-depth immunophenotyping. METHODS: To characterize the glioma TME, a mixed collective of 9 glioma patients underwent [18F]DPA-714-PET-MRI in addition to [18F]fluoro-ethyl-tyrosine (FET)-PET-MRI. Image-guided biopsy samples were immunophenotyped by multiparametric flow cytometry and immunohistochemistry. In vitro autoradiography was performed for image validation and assessment of tracer binding specificity. RESULTS: We found a strong relationship (r = 0.84, P = 0.009) between the [18F]DPA-714 uptake and the number and activation level of glioma-associated myeloid cells (GAMs). TSPO expression was mainly restricted to human leukocyte antigen D related-positive (HLA-DR+) activated GAMs, particularly to tumor-infiltrating HLA-DR+ MDSCs and TAMs. [18F]DPA-714-positive tissue volumes exceeded [18F]FET-positive volumes and showed a differential spatial distribution. CONCLUSION: [18F]DPA-714-PET may be used to non-invasively image the glioma-associated immunosuppressive TME in vivo. This imaging paradigm may also help to characterize the heterogeneity of the glioma TME with respect to the degree of myeloid cell infiltration at various disease stages. [18F]DPA-714 may also facilitate the development of new image-guided therapies targeting the myeloid-derived TME.

Tumor Vessel Normalization, Immunostimulatory Reprogramming, and Improved Survival in Glioblastoma with Combined Inhibition of PD-1, Angiopoietin-2, and VEGF.

Glioblastoma (GBM) is a non-T-cell-inflamed cancer characterized by an immunosuppressive microenvironment that impedes dendritic cell maturation and T-cell cytotoxicity. Proangiogenic cytokines such as VEGF and angiopoietin-2 (Ang-2) have high expression in glioblastoma in a cell-specific manner and not only drive tumor angiogenesis and vascular permeability but also negatively regulate T-lymphocyte and innate immune cell responses. Consequently, the alleviation of immunosuppression might be a prerequisite for successful immune checkpoint therapy in GBM. We here combined antiangiogenic and immune checkpoint therapy and demonstrated improved therapeutic efficacy in syngeneic, orthotopic GBM models. We observed that blockade of VEGF, Ang-2, and programmed cell death protein-1 (PD-1) significantly extended survival compared with vascular targeting alone. In the GBM microenvironment, triple therapy increased the numbers of CTLs, which inversely correlated with myeloid-derived suppressor cells and regulatory T cells. Transcriptome analysis of GBM microvessels indicated a global vascular normalization that was highest after triple therapy. Our results propose a rationale to overcome tumor immunosuppression and the current limitations of VEGF monotherapy by integrating the synergistic effects of VEGF/Ang-2 and PD-1 blockade to reinforce antitumor immunity through a normalized vasculature.

Human CCR5high effector memory cells perform CNS parenchymal immune surveillance via GZMK-mediated transendothelial diapedesis.

Although the CNS is immune privileged, continuous search for pathogens and tumours by immune cells within the CNS is indispensable. Thus, distinct immune-cell populations also cross the blood-brain barrier independently of inflammation/under homeostatic conditions. It was previously shown that effector memory T cells populate healthy CNS parenchyma in humans and, independently, that CCR5-expressing lymphocytes as well as CCR5 ligands are enriched in the CNS of patients with multiple sclerosis. Apart from the recently described CD8+ CNS tissue-resident memory T cells, we identified a population of CD4+CCR5high effector memory cells as brain parenchyma-surveilling cells. These cells used their high levels of VLA-4 to arrest on scattered VCAM1, their open-conformation LFA-1 to crawl preferentially against the flow in search for sites permissive for extravasation, and their stored granzyme K (GZMK) to induce local ICAM1 aggregation and perform trans-, rather than paracellular diapedesis through unstimulated primary brain microvascular endothelial cells. This study included peripheral blood mononuclear cell samples from 175 healthy donors, 29 patients infected with HIV, with neurological symptoms in terms of cognitive impairment, 73 patients with relapsing-remitting multiple sclerosis in remission, either 1-4 weeks before (n = 29), or 18-60 months after the initiation of natalizumab therapy (n = 44), as well as white matter brain tissue of three patients suffering from epilepsy. We here provide ex vivo evidence that CCR5highGZMK+CD4+ effector memory T cells are involved in CNS immune surveillance during homeostasis, but could also play a role in CNS pathology. Among CD4+ T cells, this subset was found to dominate the CNS of patients without neurological inflammation ex vivo. The reduction in peripheral blood of HIV-positive patients with neurological symptoms correlated to their CD4 count as a measure of disease progression. Their peripheral enrichment in multiple sclerosis patients and specific peripheral entrapment through the CNS infiltration inhibiting drug natalizumab additionally suggests a contribution to CNS autoimmune pathology. Our transcriptome analysis revealed a migratory phenotype sharing many features with tissue-resident memory and Th17.1 cells, most notably the transcription factor eomesodermin. Knowledge on this cell subset should enable future studies to find ways to strengthen the host defence against CNS-resident pathogens and brain tumours or to prevent CNS autoimmunity.

A Novel PKD1 Mutation Associated With Autosomal Dominant Kidney Disease and Cerebral Cavernous Malformation.

Autosomal dominant polycystic kidney disease (ADPKD) is a genetic disorder characterized by the presence of renal cysts and specific extrarenal abnormalities. ADPKD is caused by mutations in either PKD1 or PKD2 genes that encode for integral membrane proteins Polycystin-1 (PC1) and Polycystin-2 (PC2), respectively. Extrarenal involvement includes noncystic manifestations such as dilatation of the aortic root, artery dissection and intracranial aneurysms. Cerebral cavernous malformation (CCM) is a rare vascular malformation disorder characterized by closely clustered and irregularly dilated capillaries that can be asymptomatic or cause variable neurological manifestations, such as seizures, non-specific headaches, progressive or transient focal neurologic deficits, and cerebral hemorrhages. Familial CCM is typically associated with mutations in KRIT1 (CCM1), CCM2, and PDCD10 (CCM3). The co-occurrence of ADPKD and CCM has been previously described in a single patient, although genetic analysis was not performed in this study. We report here a family with ADPKD associated with CCM in two sisters. Direct sequencing of the index patient revealed a single novel heterozygous frameshift mutation in PKD1, and lack of mutations in genes usually related to CCM. This suggests that CCM represents an additional phenotype of ADPKD.

A randomized controlled phase II trial of vaccination with lysate-loaded, mature dendritic cells integrated into standard radiochemotherapy of newly diagnosed glioblastoma (GlioVax): study protocol for a randomized controlled trial.

BACKGROUND: Despite the combination of surgical resection, radio- and chemotherapy, median survival of glioblastoma multiforme (GBM) patients only slightly increased in the last years. Disease recurrence is definite with no effective therapy existing after tumor removal. Dendritic cell (DC) vaccination is a promising active immunotherapeutic approach. There is clear evidence that it is feasible, results in immunological anti-tumoral responses, and appears to be beneficial for survival and quality of life of GBM patients. Moreover, combining it with the standard therapy of GBM may allow exploiting synergies between the treatment modalities. In this randomized controlled trial, we seek to confirm these promising initial results. METHODS: One hundred and thirty-six newly diagnosed, isocitrate dehydrogenase wildtype GBM patients will be randomly allocated (1:1 ratio, stratified by O6-methylguanine-DNA-methyltransferase promotor methylation status) after near-complete resection in a multicenter, prospective phase II trial into two groups: (1) patients receiving the current therapeutic "gold standard" of radio/temozolomide chemotherapy and (2) patients receiving DC vaccination as an add-on to the standard therapy. A recruitment period of 30 months is anticipated; follow-up will be 2 years. The primary objective of the study is to compare overall survival (OS) between the two groups. Secondary objectives are comparing progression-free survival (PFS) and 6-, 12- and 24-month OS and PFS rates, the safety profile, overall and neurological performance and quality of life. DISCUSSION: Until now, close to 500 GBM patients have been treated with DC vaccination in clinical trials or on a compassionate-use basis. Results have been encouraging, but cannot provide robust evidence of clinical efficacy because studies have been non-controlled or patient numbers have been low. Therefore, a prospective, randomized phase II trial with a sufficiently large number of patients is now mandatory for clear evidence regarding the impact of DC vaccination on PFS and OS in GBM. TRIAL REGISTRATION: Protocol code: GlioVax, date of registration: 17. February 2017. Trial identifier: EudraCT-Number 2017-000304-14. German Registry for Clinical Studies, ID: DRKS00013248 (approved primary register in the WHO network) and at ClinicalTrials.gov , ID: NCT03395587 . Registered on 11 March 2017.

Progressive Multifocal Leukoencephalopathy after Ibrutinib Therapy for Chronic Lymphocytic Leukemia.

Progressive multifocal leukoencephalopathy (PML) is a devastating neurological disease observed nearly exclusively in immunocompromised patients. Recently, the introduction of monoclonal antibodies significantly inhibiting the immune system such as rituximab has led to an increase in PML cases. Although rituximab-based immunochemotherapy remains the standard of treatment for chronic lymphocytic leukemia (CLL), the importance of Bruton's tyrosine kinase inhibitors such as ibrutinib is steadily increasing. However, long-term experiences regarding possible side effects of these new substances are rare. Here, we report the development of eventually fatal PML possibly associated with ibrutinib therapy for CLL after multiple prior treatment lines, including rituximab. To the best of our knowledge, this is the first study to report such findings. Since the last course of rituximab was applied over 3 years ago, it is conceivable that the strong B cell inhibition by ibrutinib led to PML. With increased awareness of this potential side effect, further clinical studies are certainly warranted to evaluate this possible association.

CD4+ T effector memory cell dysfunction is associated with the accumulation of granulocytic myeloid-derived suppressor cells in glioblastoma patients.

BACKGROUND: Myeloid-derived suppressor cells (MDSCs) comprise a heterogeneous population of myeloid cells that are significantly expanded in cancer patients and are associated with tumor progression. METHODS: Multicolor flow cytometry was used to study the frequency, phenotype, and function of MDSCs in peripheral blood and freshly resected tumors of 52 participants with primary glioblastoma (GBM). RESULTS: The frequency of CD14(high)CD15(pos) monocytic and CD14(low)CD15(pos) granulocytic MDSCs was significantly higher in peripheral blood of GBM participants compared with healthy donors. The majority of granulocytic MDSCs consisted of CD14(low)CD15(high) neutrophilic MDSCs with high T-cell suppressive capacities. At the tumor side, we found an increase in CD14(high)CD15(pos) monocytic MDSCs and high frequencies of CD14(low)CD15(pos) granulocytic MDSCs that displayed an activated phenotype with downregulation of CD16 and upregulation of HLA-DR molecules, which did not inhibit T-cell proliferative responses in vitro. However, a strong association between granulocytic MDSCs and CD4(+) effector memory T-cells (TEM) within the tumors was detected. Tumor-derived CD4(+) TEM expressed high levels of PD-1 when compared with their blood-derived counterparts and were functionally exhausted. The respective ligand, PD-L1, was significantly upregulated on tumor-derived MDSCs, and T-cell co-culture experiments confirmed that glioma-infiltrating MDSCs can induce PD-1 expression on CD4(+) TEM. CONCLUSIONS: Our findings provide a detailed characterization of different MDSC subsets in GBM patients and indicate that both granulocytic MDSCs in peripheral blood and at the tumor site play a major role in GBM-induced T-cell suppression.

Ibuprofen and Diclofenac Restrict Migration and Proliferation of Human Glioma Cells by Distinct Molecular Mechanisms.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) have been associated with anti-tumorigenic effects in different tumor entities. For glioma, research has generally focused on diclofenac; however data on other NSAIDs, such as ibuprofen, is limited. Therefore, we performed a comprehensive investigation of the cellular, molecular, and metabolic effects of ibuprofen and diclofenac on human glioblastoma cells. METHODS: Glioma cell lines were treated with ibuprofen or diclofenac to investigate functional effects on proliferation and cell motility. Cell cycle, extracellular lactate levels, lactate dehydrogenase-A (LDH-A) expression and activity, as well as inhibition of the Signal Transducer and Activator of Transcription 3 (STAT-3) signaling pathway, were determined. Specific effects of diclofenac and ibuprofen on STAT-3 were investigated by comparing their effects with those of the specific STAT-3 inhibitor STATTIC. RESULTS: Ibuprofen treatment led to a stronger inhibition of cell growth and migration than treatment with diclofenac. Proliferation was affected by cell cycle arrest at different checkpoints by both agents. In addition, diclofenac, but not ibuprofen, decreased lactate levels in all concentrations used. Both decreased STAT-3 phosphorylation; however, diclofenac led to decreased c-myc expression and subsequent reduction in LDH-A activity, whereas treatment with ibuprofen in higher doses induced c-myc expression and less LDH-A alteration. CONCLUSIONS: This study indicates that both ibuprofen and diclofenac strongly inhibit glioma cells, but the subsequent metabolic responses of both agents are distinct. We postulate that ibuprofen may inhibit tumor cells also by COX- and lactate-independent mechanisms after long-term treatment in physiological dosages, whereas diclofenac mainly acts by inhibition of STAT-3 signaling and downstream modulation of glycolysis.

The role of ion channels in malignant brain tumors.

Malignant gliomas are the most common primary brain tumors and have poor clinical prognosis, despite multimodal therapeutic strategies. In recent years, ion channels have emerged as major players in tumor pathophysiology regarding all hallmarks of cancer. Since ion channels are easily accessible structures, they may prove to be effective targets for canner therapy, although their broad expression pattern and role in physiological processes should be taken into consideration. This review summarizes the current knowledge on the role of ion channels in the pathophysiology of malignant gliomas, especially glioblastoma, and evaluates their potential role in targeted antiglioma therapy.

Glioma tissue obtained by modern ultrasonic aspiration with a simple sterile suction trap for primary cell culture and pathological evaluation.

OBJECTIVES: Ultrasonic aspiration is widely used in the resection of brain tumors. Nevertheless, tumor tissue fragments obtained by ultrasonic aspiration are usually discarded. In this study, we demonstrate that these fragments are possible sources of material for histopathological study and tissue culture and compare their microscopic features and viability in tissue culture of cavitron ultrasonic surgical aspirator tissue fragments. METHODS: Brain tumor tissue collected by ultrasonic aspiration (CUSA EXcel®; Integra Radionics Inc.) in a simple sterile suction trap during resection was processed for primary cell culture. Cell viability and immunohistological markers were measured by the WST-1 test, microscopy and immunofluorescent evaluation. RESULTS: Six gliomas are presented to demonstrate that these tissue fragments show good preservation of histological detail and tissue viability in culture. CONCLUSION: Utilization of this material may facilitate pathological interpretation by providing a more representative sample of tumor histology as well as an adequate and sterile biosource of material for tissue culture studies.

Diclofenac inhibits lactate formation and efficiently counteracts local immune suppression in a murine glioma model.

Lactate formation in highly proliferative tumors such as malignant gliomas is associated with poor survival and contributes to the suppression of local immunity. Here, we report that diclofenac used at nontoxic concentrations significantly decreased lactate production in murine glioma cells and inhibited the expression of lactate dehydrogenase-A in vitro. Lactate reduction was accompanied by a dose-dependent inhibition of cell growth and a cell cycle arrest at the G2/M checkpoint. In the presence of diclofenac, murine bone marrow-derived dendritic cells (DCs) showed enhanced IL-12, but decreased IL-10 secretion on Toll-like receptor stimulation with R848 that correlated with reduced lactate levels in the glioma cell coculture and a blockade of signal transducers and activators of transcription 3 phosphorylation. In vivo, diclofenac treatment diminished intratumoral lactate levels and resulted in a significant delay of glioma growth. Ex vivo analyses revealed that tumor-infiltrating DCs regained their capacity to produce IL-12 on R848 stimulation. Moreover, diclofenac reduced the number of tumor-infiltrating regulatory T cells and impaired the upregulation of the Treg activation marker CD25. Nevertheless, a single intratumoral injection of R848 combined with diclofenac failed to induce an additional survival advantage in glioma-bearing mice. Further analyses illustrated that the presence of diclofenac during T-cell activation compromised INF-γ production and T-cell proliferation, indicating that immunotherapeutic approaches have to be carefully timed when combined with diclofenac. In summary, diclofenac appears as an attractive agent for targeting lactate production and counteracting local immune suppression in malignant gliomas.