A randomized control trial for evaluation of transfusion related immuno-modulation in patients with meningioma.

BACKGROUND: Blood transfusion necessity in neurosurgery varies based on surgical type, blood loss, and patient anemia. Leukocytes in red blood cells (RBCs) component release pro-inflammatory cytokines during storage, contributing to transfusion-related immunomodulation (TRIM). Our aim was to examine the impact of the leukocyte content in transfused PRBCs on patients undergoing neurosurgery for meningioma tumours. STUDY DESIGN AND METHODS: This prospective randomized controlled trial conducted from 2018 to 2020 by dividing patients randomly into non-leukoreduced (NLR) (n = 65) and leuko-reduced (LR) (n = 65) groups based on PRBCs received during surgery and hospital stay. Hospital and ICU stays, mechanical ventilation duration, and postoperative bacterial infections were observed. Hematological parameters and cytokine levels (IL-10, INF-gamma, and FAS-L) were assessed at pre-transfusion, 24 h, and 7 days post-transfusion. Data analysis included Mann-Whitney U test, Friedman test, Fisher's chi-square test, with statistical significance at p < 0.05. RESULTS: In our study, ICU and hospital stay duration showed no significant difference (p = 0.06) between groups. However, NLR group had longer mean mechanical ventilation (18 ± 40.1 h) than the LR group (12.8 ± 8.6 h). Both groups showed statistically significant increase in Fas-L level on days 1 and 7 (p < 0.05). The IL-10 levels rose 43% in the NLR group, while and decreased by 7% the LR group on day 1. On day 7, IL-10 increased by 75% in NLR and decreased by 40% in LR, with no significance (p > 0.05). CONCLUSION: In conclusion, leukoreduction appeared to offer some immune response protection in term of reducing mechanical ventilation timings and cytokine level changes.

Hsa_circ_0004872 mitigates proliferation, metastasis and immune escape of meningioma cells by suppressing PD-L1.

Meningioma is a prevalent intracranial malignancy known for its aggressive growth. Circular RNAs (circRNAs) play a crucial role in the development of various cancers. However, their involvement in meningioma remains understudied. This study aimed to investigate the function and underlying mechanism of hsa_circ_0004872 in meningioma. The molecular expression of hsa_circ_0004872, PD-L1 and EIF4A3 was identified by RT-qPCR and/or western blot assays. Cell viability, migration, and invasion were assessed through CCK-8 and Transwell assays, respectively. Cytotoxicity was determined using an LDH assay, and cell apoptosis was monitored by flow cytometry. The RNA and protein interactions were assessed through RNA-protein immunoprecipitation (RIP) and RNA pull down analyses. Our findings revealed that hsa_circ_0004872 expression was significantly downregulated in both meningioma tissue samples and cells. Overexpression of hsa_circ_0004872 inhibited the proliferation, metastasis, and immune escape of meningioma cells, as well as enhanced the cytotoxicity of CD8+ T cells by suppressing PD-L1. Furthermore, hsa_circ_0004872 directly interacted with EIF4A3, leading to the degradation of PD-L1 mRNA. Finally, inhibiting EIF4A3 improved the proliferation, metastasis, and immune escape of meningioma cells, as well as the cytotoxicity of CD8+ T cells. Our study demonstrated that hsa_circ_0004872 mitigated the proliferation, metastasis,and immune escape of meningioma cells by targeting the EIF4A3/PD-L1 axis. These findings suggested that hsa_circ_0004872 and EIF4A3 might serve as promising biological markers and therapeutic targets for meningioma treatment.

The Molecular and Immunological Landscape of Meningiomas.

Meningiomas are the most common primary intracranial tumors in adults and typically have a slow-growing and benign nature. However, there is also a substantial subset of meningiomas that shows aggressive clinical behavior and is refractory to standard treatment modalities, which are still limited to surgery and/or radiotherapy. Despite intensive research, no systemic treatment options are yet available in the clinic for these challenging tumors, resulting in poor patient outcome. Intensive research on the molecular pathogenesis of meningiomas has led to improved diagnostic tools, but so far there is no standardized implementation for the molecular profiling of these tumors for clinical practice. Recent research advances have also focused on the immunophenotyping of meningiomas, leading to several clinical trials examining the use of immune checkpoint blockade therapy in patients with clinically aggressive subtypes. In this review, we aim to summarize the current knowledge on the molecular and immunological landscape of meningiomas in detail and provide current and progressive ideas for future directions.

Investigation of the status of immune checkpoint molecules (PD-L1 and PD-1) in meningiomas by immunohistochemistry.

Background/aim: Meningiomas are the most common primary brain tumors of the central nervous system. Immunotherapy is a promising treatment method applied in many types of cancer. There is no standard and effective medical treatment to reduce recurrence and mortality in cases of incomplete resection of meningiomas and in high-grade cases. In order to investigate medical treatments in addition to surgery and radiotherapy, in this study, the status of immune checkpoint molecules (PD-L1/PD-1), which are the target of immunotherapy, in meningiomas was investigated. Materials and methods: Four hundred two cases of meningioma diagnosed between 2007 and 2020 at our institution were used. New blocks were prepared from the appropriate blocks of the cases using the tissue microarray method. Sections obtained from these blocks were immunohistochemically stained with PD-1 and PD-L1 antibodies. Obtained data were interpreted with statistical analysis. Results: Expression of PD-L1 was observed in 28.4% of meningiomas. Staining rates are higher in high-grade tumors. The staining rate of PD-L1 in the tumor increased significantly with pattern loss. PD-L1 expression in immune cells is 19.9%. Immune cell expression and the number of expressing immune cells correlate with spontaneous necrosis. Immune cell expression and the number of expressing immune cells are increased in high-grade meningiomas. PD-1 expression in immune cells is 9.0%, and this correlates with brain invasion. Conclusions: With these data, it was observed that the expression of immune checkpoint molecules PD-L1 and PD-1 increased especially in high-grade meningiomas. It may be the subject of research that these molecules may be targets of immunotherapy in the treatment of meningiomas.

NF2 mutation status and tumor mutational burden correlate with immune cell infiltration in meningiomas.

BACKGROUND: The tumor microenvironment is an emerging biomarker of underlying genomic heterogeneity and response to immunotherapy-based treatment regimens in solid malignancies. How tumor mutational burden influences the density, distribution, and presence of a localized immune response in meningiomas is unknown. METHODS: Representative hematoxylin and eosin slides were reviewed at 40X to assess for the density of inflammatory cells. Lymphocytes and macrophages were quantified in the following ordinal manner: 0 = not present, 1 = 1-25 cells present, and 2 = greater than 26 cells present. Immune cell infiltrate grade was scored for both scattered and aggregated distributions. Next generation targeted sequencing was performed on all meningiomas included in this study. RESULTS: One hundred and forty-five meningiomas were evaluated in this study. Lymphocytes were observed in both scattered (95.9%) and aggregated (21.4%) distributions. A total of 115 (79.3%) meningiomas had 1-25 scattered lymphocytes, and 24 (16.6%) had > 25 scattered lymphocytes, and 6 (4.1%) had no scattered lymphocytes. Twenty (13.8%) meningiomas had 1-25 aggregated lymphocytes. Eleven (7.6%) had > 25 aggregated lymphocytes and 114 (78.6%) had no aggregated lymphocytes. Six (4.1%) meningiomas had 1-25 aggregated macrophages, 5 (3.4%) had > 25 aggregated macrophages, and 134 (92.4%) had no aggregated macrophages. Density of aggregated lymphocytes and aggregated macrophages were associated with higher tumor grade, P = 0.0071 and P = 0.0068, respectively. Scattered lymphocyte density was not associated with meningioma grade. The presence of scattered lymphocytes was associated with increased tumor mutational burden. Meningiomas that did not have scattered lymphocytes had a mean number of single mutations of 2.3 ± 2.9, compared with meningiomas that had scattered lymphocytes, 6.9 ± 20.3, P = 0.03. NF2 mutations were identified in 59 (40.7%) meningiomas and were associated with increased density of scattered lymphocytes. NF2 mutations were seen in 0 (0%) meningiomas that did not have scattered lymphocytes, 46 (40.0%) meningiomas that had 1-25 scattered lymphocytes, and 13 (54.2%) meningiomas that had > 25 scattered lymphocytes, P = 0.046. CONCLUSIONS: Our findings suggest that distribution of immune cell infiltration in meningiomas is associated with tumor mutational burden. NF2 mutational status was associated with an increasing density of scattered lymphocytes. As the role of immunotherapy in meningiomas continues to be elucidated with clinical trials that are currently underway, these results may serve as a novel biomarker of tumor mutational burden in meningiomas.

Identification of key genes and pathways associated with resting mast cells in meningioma.

BACKGROUND: To identify candidate key genes and pathways related to resting mast cells in meningioma and the underlying molecular mechanisms of meningioma. METHODS: Gene expression profiles of the used microarray datasets were obtained from the Gene Expression Omnibus (GEO) database. GO and KEGG pathway enrichments of DEGs were analyzed using the ClusterProfiler package in R. The protein-protein interaction network (PPI), and TF-miRNA- mRNA co-expression networks were constructed. Further, the difference in immune infiltration was investigated using the CIBERSORT algorithm. RESULTS: A total of 1499 DEGs were identified between tumor and normal controls. The analysis of the immune cell infiltration landscape showed that the probability of distribution of memory B cells, regulatory T cells (Tregs), and resting mast cells in tumor samples were significantly higher than those in the controls. Moreover, through WGCNA analysis, the module related to resting mast cells contained 158 DEGs, and KEGG pathway analysis revealed that the DEGs were dominant in the TNF signaling pathway, cytokine-cytokine receptor interaction, and IL-17 signaling pathway. Survival analysis of hub genes related to resting mast cells showed that the risk model was constructed based on 9 key genes. The TF-miRNA- mRNA co-regulation network, including MYC-miR-145-5p, TNFAIP3-miR-29c-3p, and TNFAIP3-hsa-miR-335-3p, were obtained. Further, 36 nodes and 197 interactions in the PPI network were identified. CONCLUSION: The results of this study revealed candidate key genes, miRNAs, and pathways related to resting mast cells involved in meningioma development, providing potential therapeutic targets for meningioma treatment.

Advances in Molecular Classification and Therapeutic Opportunities in Meningiomas.

PURPOSE OF REVIEW: Our understanding of the genetic and epigenetic alterations in meningioma and the underlying tumor biology of meningioma has significantly changed over the past decade and resulted in revision of prognostically relevant meningioma subclasses within and beyond the WHO classification of CNS tumors. RECENT FINDINGS: The 2016 WHO classification of CNS tumors recognizes WHO grade I, II, and III based on histopathological features. Recent work has identified genetic alterations with prognostic implications, including mutations of the TERT promoter, loss of function of the DMD gene, and inactivation of the tumor suppressor BAP-1. Studies of DNA methylation patterns in meningiomas have resulted in a novel and prognostically relevant meningioma subclassification schema. There have been major advances in our understanding of prognostically relevant genetic and epigenetic changes in meningioma which will hopefully allow for improvement in clinical trial design and the development of more effective therapies for meningioma.

The Length Distribution and Multiple Specificity of Naturally Presented HLA-I Ligands.

HLA-I molecules bind short peptides and present them for recognition by CD8+ T cells. The length of HLA-I ligands typically ranges from 8 to 12 aa, but variability is observed across different HLA-I alleles. In this study we collected recent in-depth HLA peptidomics data, including 12 newly generated HLA peptidomes (31,896 unique peptides) from human meningioma samples, to analyze the peptide length distribution and multiple specificity across 84 different HLA-I alleles. We observed a clear clustering of HLA-I alleles with distinct peptide length distributions, which enabled us to study the structural basis of peptide length distributions and predict peptide length distributions from HLA-I sequences. We further identified multiple specificity in several HLA-I molecules and validated these observations with binding assays. Explicitly modeling peptide length distribution and multiple specificity improved predictions of naturally presented HLA-I ligands, as demonstrated in an independent benchmarking based on the new human meningioma samples.

Analysis of the inflammatory tumor microenvironment in meningeal neoplasms.

BACKGROUND: Properties of the inflammatory tumor microenvironment are associated with disease subtype, grade, and prognosis in various cancer entities. As immune-modulatory therapies are currently being explored in patients with meningeal neoplasms, we investigated their inflammatory microenvironment (meningiomas and solitary fibrous tumor/hemangiopericytoma (SFT/HPC)). MATERIALS AND METHODS: 74 meningeal tumor specimens: (10/74 (13.5%) atypical meningioma; 8/74 (10.8%) anaplastic meningioma; 8/74 (10.8%) chordoid meningioma; 9/74 (12.2%) fibroblastic meningioma; 10/74 (13.5%) transitional meningioma; 3/74 (4.1%) rhabdoid meningioma; 7/74 (9.5%) meningothelial meningioma; SFT/HPC (19/74 (25.7%) were retrieved from the Neuro-Biobank, Medical University of Vienna, Austria. RESULTS: Tumor-infiltrating lymphocyte (TIL) infiltration could be observed in the majority of the investigated specimens (CD3+: 66/74 (89.2%); CD8+: 47/74 (63.5%); CD45RO+: 29/73 (39.2%); FOXP3+ 19/74 (25.7%); PD1+: 3/74 (4.1%). No difference in TIL infiltration was observed between SFT/HPC and meningioma cases. Higher density of FOXP3+ TILs was observed with increasing WHO grade in meningioma specimens (p = 0.005). Membranous programmed cell death ligand 1 (PD-L1) expression was observed in 4/74 (5.4%) specimens, with 3/74 (4.1%) presenting with 1% and 1/74 (1.4%) with 3% PD-L1 expressing tumor cells. Lymphatic vessels as identified by podoplanin immunohistochemistry were observed in 10/74 (13.5%) specimens and were significantly associated with presence of membranous PD-L1 expression on tumor cells (p = 0.003). CONCLUSION: Infiltration by various TIL subtypes can be observed in the majority of meningeal neoplasms, with enrichment of FOXP3-positive regulatory T-cells in higher-grade meningioma. PD-L1 expression on tumor cells was only infrequently found. A better understanding of the pathobiological role of the immune system in meningeal neoplasms may facilitate development of immunomodulatory treatment approaches in meningeal tumors.

Systemic and local immunosuppression in patients with high-grade meningiomas.

AIM: Despite current treatments, high-grade meningiomas continue to have a poor prognosis. Immunotherapy targeting immune checkpoints, such as PD-L1, has demonstrated significant success in controlling numerous malignancies. In this study, we investigate the extent of systemic and local immunosuppression in meningiomas to assess the potential benefit of immune checkpoint inhibitors for the treatment of high-grade meningiomas. METHODS: Peripheral blood was collected from patients undergoing resection of meningiomas (WHO grade I, n = 18; grade II, n = 25; grade III, n = 10). Immunosuppressive myeloid cells (CD45+CD11b+PD-L1+), myeloid-derived suppressor cells (MDSCs) (CD11b+CD33+HLA-DRlow), and regulatory T cells (Tregs) (CD3+CD4+CD25+FoxP3+) were quantified through flow cytometry. Tissue sections from the same patients were assessed for PD-L1 expression and T cell infiltration via immunohistochemistry. RESULTS: Patients with grade III meningiomas demonstrated increased peripheral monocyte PD-L1 compared to patients with grade I/II meningiomas and healthy controls. Peripheral MDSC abundance was increased in grades II and III meningioma patients. PD-L1 staining of meningioma tissue demonstrated increased positivity in grade III meningiomas. Intratumoral PD-L1 was not associated with progression-free survival. High-grade meningiomas had increased T-cell infiltration. However, a significant proportion of these T cells were exhausted PD1+ T cells and immunosuppressive Tregs. CONCLUSIONS: Patients with meningiomas exhibit signs of peripheral immunosuppression, including increased PD-L1 on myeloid cells and elevated MDSC abundance proportional to tumor grade. Additionally, the tumors express substantial PD-L1 proportional to tumor grade. These results suggest a role for immune checkpoint inhibitors targeting the PD-L1/PD-1 pathway in combination with standard therapies for the treatment of high-grade meningiomas.

Non-NF2 mutations have a key effect on inhibitory immune checkpoints and tumor pathogenesis in skull base meningiomas.

AIMS: Skull base meningiomas represent approximately 25% of all meningiomas, nearly 20% of which are atypical or anaplastic. To date, effective medical treatments for meningiomas are still lacking. Genetic aberrations (TRAF7, KLF4, AKT1, and SMO) and the effects of genetic aberrations on the expression of inhibitory immune checkpoint molecules (PD-L1, IDO, and TDO2) in skull base meningiomas are still unclear. METHODS: Genetic alterations in the four genes were identified in 92 skull base meningiomas by Sanger sequencing. The expression differences in immune checkpoints between mutant and wild-type (WT) tumors were determined by immunohistochemistry (IHC) and Western blot (WB). RESULTS: The four mutations were not concurrently detected in the patients with skull base meningiomas. Among the tumors from the KLF4-mutated group, almost half were petroclival meningiomas. KLF4- and TRAF7-mutated tumors were predominantly secretory meningiomas. SMO-mutated tumors exhibited higher calcification, and half of these tumors were observed in the brain midline. Receiver operating characteristic curve analysis indicated that tumor volume can predict KLF4 and TRAF7 mutation status with high sensitivity and specificity, respectively. The IHC and WB analyses indicated that PD-L1, IDO, and TDO2 levels in tumors with TRAF7 mutations were significantly higher than those in WT tumors. Meanwhile, there was a significant difference in TDO2 between tumors with AKT1 mutations and WT tumors. Specifically, TRAF7 mutations could play a key role in skull base meningiomas by regulating the expression of inhibitory immune checkpoints and thus suppressing immune responses. CONCLUSIONS: Checkpoint inhibitors may be potential strategies for targeted immunotherapies of these mutant meningiomas.

The role and regulatory mechanism of IL-1ß on the methylation of the NF2 gene in benign meningiomas and leptomeninges.

Methylation of the neurofibromatosis type 2 (NF2) gene in low-grade meningioma (WHO grade I) has crucial roles in tumorigenesis and development. Meningioma formation might also occur in the setting of an inflammatory microenvironment. However, the association between inflammation and the methylation of NF2 remains unclear. The present study investigates the role and regulatory mechanism of IL-1ß, one of the most important pro-inflammatory cytokines, in the methylation of NF2 in benign meningioma. Three primary low-grade meningioma cells and leptomeningeal cells were cultured. CCK-8 and BrdU assays demonstrated that proliferation of meningioma/leptomeningeal cells treated with IL-1ß occurred in a dose- and time-dependent manner. Methylation-specific PCR verified that IL-1ß induced methylation of the NF2 promoter and decreased NF2/merlin expression in meningioma/leptomeningeal cells. Real-time PCR, western blotting, and immunofluorescence showed that IL-1ß up-regulated DNMT1 in meningioma cells and DNMT1/3b in leptomeningeal cells but did not up-regulate DNMT3a. After co-treatment with the DNMT inhibitor 5-Aza-2'-deoxycytidine and DNMT siRNA, methylation of NF2 induced by IL-1ß was attenuated and merlin expression was restored. Furthermore, we showed that DNMT1 in meningiomas and DNMT1/3b in leptomeninges were regulated via activation of the MAPK (p38, ERK, JNK) and NF-κB pathways. These results suggest that IL-1ß induces methylation of NF2 by up-regulating DNMT1 in benign meningioma cells and DNMT1/3b in leptomeningeal cells via MAPK and NF-κB pathways. Therefore, NF2 methylation is a linker between IL-1ß and tumor development, and DNMTs might be potential therapeutic targets in meningioma for regulating NF2 and inhibiting tumor development. © 2016 Wiley Periodicals, Inc.

Tumor infiltrating immune cells in gliomas and meningiomas.

Tumor-infiltrating immune cells are part of a complex microenvironment that promotes and/or regulates tumor development and growth. Depending on the type of cells and their functional interactions, immune cells may play a key role in suppressing the tumor or in providing support for tumor growth, with relevant effects on patient behavior. In recent years, important advances have been achieved in the characterization of immune cell infiltrates in central nervous system (CNS) tumors, but their role in tumorigenesis and patient behavior still remain poorly understood. Overall, these studies have shown significant but variable levels of infiltration of CNS tumors by macrophage/microglial cells (TAM) and to a less extent also lymphocytes (particularly T-cells and NK cells, and less frequently also B-cells). Of note, TAM infiltrate gliomas at moderate numbers where they frequently show an immune suppressive phenotype and functional behavior; in contrast, infiltration by TAM may be very pronounced in meningiomas, particularly in cases that carry isolated monosomy 22, where the immune infiltrates also contain greater numbers of cytotoxic T and NK-cells associated with an enhanced anti-tumoral immune response. In line with this, the presence of regulatory T cells, is usually limited to a small fraction of all meningiomas, while frequently found in gliomas. Despite these differences between gliomas and meningiomas, both tumors show heterogeneous levels of infiltration by immune cells with variable functionality. In this review we summarize current knowledge about tumor-infiltrating immune cells in the two most common types of CNS tumors-gliomas and meningiomas-, as well as the role that such immune cells may play in the tumor microenvironment in controlling and/or promoting tumor development, growth and control.

Secretion and immunogenicity of the meningioma-associated antigen TXNDC16.

In a previous study, we identified thioredoxin domain containing 16 (TXNDC16) as a meningioma-associated Ag by protein macroarray screening. Serological screening detected autoantibodies against TXNDC16 exclusively in meningioma patients' sera and not in sera of healthy controls. TXNDC16 was previously found to be an endoplasmic reticulum (ER)-luminal glycoprotein. In this study, we show an additional ER-associated localization of TXNDC16 in the cytosol by in vitro synthesis, molecular mass shift assay, and flow cytometry. We were able to show TXNDC16 secretion in different human cell lines due to masked and therefore nonfunctional ER retrieval motif. A previously indicated exosomal TXNDC16 secretion could not be confirmed in HEK293 cells. The secreted serum protein TXNDC16 is bound in circulating immune complexes, which were found both in meningioma and healthy blood donor sera. Employing a customized array with 163 overlapping TXNDC16 peptides and measuring autoantibody reactivity, we achieved discrimination of meningioma sera from healthy controls with an accuracy of 87.2% using a set of only five immunogenic TXNDC16 epitopes.

Ligation-anchored PCR unveils immune repertoire of TCR-beta from whole blood.

BACKGROUND: As one of the genetic mechanisms for adaptive immunity, V(D)J recombination generates an enormous repertoire of T-cell receptors (TCRs). With the development of high-throughput sequencing techniques, systematic exploration of V(D)J recombination becomes possible. Multiplex PCR has been previously developed to assay immune repertoire; however, the use of primer pools leads to inherent biases in target amplification. In our study, we developed a "single-primer" ligation-anchored PCR method that may amplify the repertoire with much less biases. RESULTS: By utilizing a universal primer paired with a single primer targeting the conserved constant region, we amplified TCR-beta (TRB) variable regions from total RNA extracted from blood. Next-generation sequencing libraries were then prepared for Illumina HiSeq 2500 sequencer, which generates 151-bp read length to cover the entire V(D)J recombination region. We evaluated this approach on blood samples from healthy donors and from patients with malignant and benign meningiomas. Mapping of sequencing data showed that 64% to 96% of mapped TCRV-containing reads belong to TRB subtype. An increased usage of specific V segments and V-J pairing were observed in malignant meningiomas samples. The CDR3 sequences of the expanded V-J pairs were distinct in each malignant individual, even for pairing of TRBV7-3 with TRBJ2-2 that showed increased usage in both cases. CONCLUSIONS: We demonstrated the technical feasibility and effectiveness of ligation-anchored PCR approach in capturing the TCR-beta landscapes. Further development of this technology may enable a comprehensive delineation of immune repertoire, including other forms of TCRs as well as immunoglobulins.

Mast cells in meningiomas and brain inflammation.

BACKGROUND: Research focus in neuro-oncology has shifted in the last decades towards the exploration of tumor infiltration by a variety of immune cells and their products. T cells, macrophages, B cells, and mast cells (MCs) have been identified. METHODS: A systematic review of the literature was conducted by searching PubMed, EMBASE, Google Scholar, and Turning Research into Practice (TRIP) for the presence of MCs in meningiomas using the terms meningioma, inflammation and mast cells. RESULTS: MCs have been detected in various tumors of the central nervous system (CNS), such as gliomas, including glioblastoma multiforme, hemangioblastomas, and meningiomas as well as metastatic brain tumors. MCs were present in as many as 90 % of all high-grade meningiomas mainly found in the perivascular areas of the tumor. A correlation between peritumoral edema and MCs was found. INTERPRETATION: Accumulation of MCs in meningiomas could contribute to the aggressiveness of tumors and to brain inflammation that may be involved in the pathogenesis of additional disorders.

Integrin-based meningioma cell migration is promoted by photon but not by carbon-ion irradiation.

PURPOSE: Sublethal doses of photon irradiation (IR) are suspected to increase tumor cell migration and support locoregional recurrence of disease, which has already been shown in other cell lines. This manuscript describes the effect of photon and carbon-ion IR on WHO class I meningioma cell migration and provides an approach to the underlying cellular mechanisms. MATERIALS AND METHODS: Meningioma cells were gained operatively at the university hospital in Homburg/Saar, Germany. For migration, membranes (8-µm pore sizes) were coated with collagen I, with collagen IV, and with fibronectin. Cells were analyzed in migration experiments with or without serum stimulation, with or without photon and carbon IR 24 h prior to experiments, and with or without integrin antibodies. Fluorescence-activated cell sorting (FACS) analyses of the integrins ανß1, ανß3, and ανß5 were performed without IR and 6, 12 and 24 h after IR. Enzyme-linked immunosorbent assay (ELISA) analyses of matrix metalloproteinases (MMP)-2 and MMP-9 were realized with and without IR after cells were cultured on collagen I, collagen IV, or fibronectin for 24 h. Cells and supernatants for FACS and ELISA were stored at - 18 °C. The significance level was set at 5 % using both Student's t test and two-way ANOVA. RESULTS: Migration of meningioma cells was serum-inducible (p < 0.001). It could be increased by photon IR (p < 0.02). The integrins ανß1 and ανß5 showed a 21 and 11 % higher expression after serum stimulation (not significant), respectively, and ανß1 expression was raised by 14 % (p = 0.0057) after photon IR. Antibody blockage of the integrins ανß1 and ανß5 inhibited serum- and photon-induced migration. Expression of MMP-2 and MMP-9 remained unchanged after both IR and fetal bovine serum (FBS). Carbon-ion IR left both integrin expression and meningioma cell migration unaffected. CONCLUSION: Photon but not carbon-ion IR promotes serum-based meningioma cell migration. Fibronectin receptor integrin ανß1 signaling can be identified as an important mechanism for serum- and photon-induced migration of WHO class I meningioma cells.

Similar immunity profiles in patients with meningioma and glioma tumors despite differences in the apoptosis and necrosis of circulating lymphocyte and monocyte populations.

AIM: The present study aims to compare the host immune responses induced by benign (meningiomas) and malignant (gliomas) brain tumors. METHODS: Peripheral blood samples from 8 meningioma and 7 glioma patients collected pre- and post operatively were assessed for cell-mediated immunity, humoral immunity and IL-6, IL-8 and TNF-a expression. Apoptosis and necrosis of circulating lymphocytes and monocytes were evaluated by Annexin/PI, while DNA analysis was applied to trace circulating cells with an abnormal DNA content. RESULTS: Cell-mediated immunity was similar in the two groups either pre- or post- operatively. However, differences in the apoptosis and necrosis of circulating lymphocytes and monocytes were observed. Menigioma patients were characterized by increased percentage of apoptotic lymphocytes and necrotic monocytes pre-operatively and apoptotic monocytes postoperatively. In contrast glioma patients showed an increase in necrotic monocytes postoperatively. Humoral immunity and cytokine expression were at comparable levels both pre- and post-operatively. IL-6 expression was significant elevated after surgery in both groups. Circulating aneuploid cells were identified in three glioma patients pre-operatively, by DNA analysis. CONCLUSION: The presented data indicate that meningioma and glioma tumors trigger comparable systemic host immunity response mediated by impairments in cell-mediated immunity due to alternations in apoptosis and necrosis that also influence their shift towards the Th2 immunity profile. Moreover, the presented evidences on the circulation of aneuploid cells in glioma patients may substantiate further the immunosuppressive phenotype detected in these patients and offer a mechanism for the rare cases that extra- neural dissemination was observed without previous surgical intervention.

Investigation of the Status of Immune Checkpoint Molecules in Meningiomas by Immunohistochemistry.

AIM: To investigate the status of immune checkpoint molecules (CTLA-4 and TIM-3) in meningiomas and thus contribute to the development of new personalized treatment strategies. MATERIAL AND METHODS: We utilized 402 cases of meningioma for this study. New blocks were prepared using the tissue microarray method, and sections obtained from these blocks were immunohistochemically stained with CTLA-4 and TIM-3 antibodies. Subsequently, statistical analysis were performed. RESULTS: Our findings revealed that CTLA-4 expression were observed in 25.1% of meningiomas. CTLA-4 expression and the number of expressing lymphocytes were found to be significantly higher in high-grade tumors and in those with brain invasion. Meningiomas with staining of immune cells with TIM-3 are 3.5%, and the tumor grade was correlated with the number of immune cells expressing TIM-3. CONCLUSION: Immune checkpoint molecules (CTLA-4 and TIM-3) with varying levels of expression can serve as prognostic and predictive biomarkers, as well as important targets for therapy. Drugs developed for CTLA-4 and TIM-3 molecules may prove to be more effective in treating meningiomas with high-grade, brain-invading, spontaneous necrosis, and macronucleolus.