Significance of p53 and CD31 in astrogliomas

All-in-One Nanowire Assay System for Capture and Analysis of Extracellular Vesicles from an ex Vivo Brain Tumor Model

Extracellular vesicles (EVs) have promising potential as biomarkers for early cancer diagnosis. The EVs have been widely studied as biological cargo containing essential biological information not only from inside vesicles such as nucleic acids and proteins but also from outside vesicles such as membrane proteins and glycolipids. Although various methods have been developed to isolate EVs with high yields such as captures based on density, size, and immunoaffinity, different measurement systems are needed to analyze EVs after isolation, and a platform that enables all-in-one analysis of EVs from capture to detection in multiple samples is desired. Since a nanowire-based approach has shown an effective capability for capturing EVs via surface charge interaction compared to other conventional methods, here, we upgraded the conventional well plate assay to an all-in-one nanowire-integrated well plate assay system (i.e., a nanowire assay system) that enables charge-based EV capture and EV analysis of membrane proteins. We applied the nanowire assay system to analyze EVs from brain tumor organoids in which tumor environments, including vascular formations, were reconstructed, and we found that the membrane protein expression ratio of CD31/CD63 was 1.42-fold higher in the tumor organoid-derived EVs with a p-value less than 0.05. Furthermore, this ratio for urine samples from glioblastoma patients was 2.25-fold higher than that from noncancer subjects with a p-value less than 0.05 as well. Our results demonstrated that the conventional well plate method integrated with the nanowire-based EV capture approach allows users not only to capture EVs effectively but also to analyze them in one assay system. We anticipate that the all-in-one nanowire assay system will be a powerful tool for elucidating EV-mediated tumor-microenvironment crosstalk.

P4HA1 Regulates CD31 via COL6A1 in the Transition of Glioblastoma Stem-Like Cells to Tumor Endothelioid Cells

Glioblastoma multiforme (GBM) is a common intracranial malignancy characterized by abundant and aberrant vasculature. The efficiency of existing antivascular treatments remains unsatisfactory. The transition of glioblastoma stem-like cells (GSCs) into tumor endothelioid cells (ECs) has been thought to cause glioma neovascularization and anti-angiogenesis tolerance, but the mechanisms regulating glioma transdifferentiation remains unclear. Our previous study found that P4HA1 regulates GSCs vascular mimicry in a hypoxic microenvironment, but the detailed molecular mechanism has not been determined. In this study, candidate protein COL6A1 was screened by mass spectrometry. In vitro experiments show that P4HA1 regulates the expression of CD31 via COL6A1, with the levels of expression of P4HA1, COL6A1 and the vascular endothelial molecular markers CD31 showing positive correlations in vivo assay. Altering the expression of P4HA1 in GSCs altered the expression of COL6A1 and CD31, thereby inducing glioma angiogenesis. In conclusion, this study revealed that the P4HA1/COL6A1 axis modulates the transdifferentiation process of GSCs into ECs. Interrupting this signaling axis can inhibit glioma angiogenesis, suggesting that this axis may be a novel target for antivascular therapy in patients with glioma.

IDH1 mutation is associated with lower expression of VEGF but not microvessel formation in glioblastoma multiforme

Introduction

Glioblastoma multiforme (GBM) represents the most malignant primary brain tumor characterized by pathological vascularization. Mutations in isocitrate dehydrogenases 1 and 2 (IDH1 and IDH2) were observed in GBM. We aimed to assess the intra-tumor hypoxia, angiogenesis and microvessel formation in GBM and to find their associations with IDH1 mutation status and patients prognosis.

Methods

52 patients with a diagnosis of GBM were included into the study. IDH1 R132H mutation was assessed by RT-PCR from FFPE tumor samples obtained during surgery. The expression of markers of hypoxia (HIF2α), angiogenesis (VEGF), tumor microvascularity (CD31, CD34, vWF, CD105), and proliferation (Ki-67) were assessed immunohistochemically (IHC). IDH1 mutation and IHC markers were correlated with the patient survival.

Results

20 from 52 GBM tumor samples comprised IDH1 R132H mutation (38.5%). The majority of mutated tumors were classified as secondary glioblastomas (89.9%). Patients with IDH1 mutated tumors experienced better progression-free survival (P = 0.037) as well as overall survival (P = 0.035) compared with wild type tumors. The significantly lower expression of VEGF was observed in GBM with IDH1 mutation than in wild type tumors (P = 0.01). No such association was found for microvascular markers. The increased expression of newly-formed microvessels (ratio CD105/CD31) in tumor samples was associated with worse patient’s progression-free survival (P = 0.026).

Summary

No increase in HIF/VEGF-mediated angiogenesis was observed in IDH1-mutated GBM compared with IDH1 wild type tumors. The histological assessment of the portion of newly-formed microvessels in tumor tissue can be used for the prediction of GBM patient’s prognosis.

Evaluation of ALCAM, PECAM-1 and selectin levels in intracranial meningiomas

OBJECTIVES

Cell adhesion molecules play a major role in various pathological states. The aim of this study was to evaluate the tissue levels of selectins (E-, L-, and P-Selectins), activated leukocyte cell adhesion molecule (ALCAM) and platelet endothelial cell adhesion molecule-1 (PECAM-1) in intracranial meningiomas and compare with the levels in control tissues.

PATIENTS AND METHODS

20 consecutive patients who were operated on meningiomas (grade-I: 17 and grade-II: 3) and 15 cerebral tissues obtained during the autopsy procedures as a resource for the healthy controls were included in this study.

RESULTS

All three selectins', ALCAM and PECAM-1 levels were found to be significantly higher in meningiomas when compared with the control tissues (p<0.001, p<0.001, p<0.001, p<0.05, p<0.001), respectively.

CONCLUSIONS

According to our results, the adhesion molecules were found to be higher in meningiomas suggesting that they may be involved in the pathological process of this type of brain tumors. We conceive that developing alternate therapies such as immunotherapeutic approaches against brain tumors might be amendatory in the treatment. Since this is the first study performed in meningioma type brain tumors demonstrating and comparing the levels of various adhesion molecules with control tissues, further clinical and experimental studies are needed to support our current findings with higher number of patients.

Antitumor activity of SAHA, a novel histone deacetylase inhibitor, against murine B cell lymphoma A20 cells in vitro and in vivo

Suberoylanilide hydroxamic acid (SAHA; vorinostat), the second generation of histone deacetylase (HDAC) inhibitor, has been approved for the treatment of cutaneous manifestations of cutaneous T cell lymphoma (CTCL). It has also shown its anticancer activity over a large range of other hematological and solid malignancies, but few studies have been reported in B cell lymphoma. In this study, we aimed to investigate the antitumor activity of SAHA on murine B cell lymphoma cell line A20 cells. We treated A20 cells with different concentrations of SAHA. The effect of SAHA on the proliferation of A20 cells was studied by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium (MTT) assay in vitro; the anti-proliferation activity in vivo was evaluated by proliferating cell nuclear antigen (PCNA) of xenograft tumor tissues through immunocytochemical staining. Apoptosis were detected by Hoechst 33258 staining and Annexin V/propidium iodide (PI) double-labeled cytometry in vitro. The effect of SAHA on cell cycle of A20 cells was studied by a propidium iodide method. Autophagic cell death induced by SAHA was confirmed by transmission electron microscopy (TEM). Angiogenesis marker (CD31) was measured by immunocytochemical staining to investigate the anti-angiogenic effect of SAHA. Western blot was used to detect the expression of signaling pathway factors (phospho-AKT, phospho-ERK, AKT, ERK, Nur77, HIF-1α, and VEGF). Our results showed that SAHA inhibited the proliferation of A20 cells in a time- and dose-dependent manner, induced cell apoptosis and G0/G1 phase arrest of cell cycle, promoted autophagic cell death, and suppressed tumor progress in NCI-A20 cells nude mice xenograft model in vivo. SAHA decreased the activation of AKT (phospho-AKT: p-AKT) and ERK1/2 (phospho-ERK: p-ERK) proteins and inhibited the expression of pro-angiogenic factors (VEGF and HIF-1α), downregulated its downstream signaling factor (Nur77), which might be contributed to the antitumor mechanisms of SAHA.

The combination of cannabidiol and Δ9-tetrahydrocannabinol enhances the anticancer effects of radiation in an orthotopic murine glioma model

High-grade glioma is one of the most aggressive cancers in adult humans and long-term survival rates are very low as standard treatments for glioma remain largely unsuccessful. Cannabinoids have been shown to specifically inhibit glioma growth as well as neutralize oncogenic processes such as angiogenesis. In an attempt to improve treatment outcome, we have investigated the effect of Δ(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD) both alone and in combination with radiotherapy in a number of glioma cell lines (T98G, U87MG, and GL261). Cannabinoids were used in two forms, pure (P) and as a botanical drug substance (BDS). Results demonstrated a duration- and dose-dependent reduction in cell viability with each cannabinoid and suggested that THC-BDS was more efficacious than THC-P, whereas, conversely, CBD-P was more efficacious than CBD-BDS. Median effect analysis revealed all combinations to be hyperadditive [T98G 48-hour combination index (CI) at FU50, 0.77-1.09]. Similarly, pretreating cells with THC-P and CBD-P together for 4 hours before irradiation increased their radiosensitivity when compared with pretreating with either of the cannabinoids individually. The increase in radiosensitivity was associated with an increase in markers of autophagy and apoptosis. These in vitro results were recapitulated in an orthotopic murine model for glioma, which showed dramatic reductions in tumor volumes when both cannabinoids were used with irradiation (day 21: 5.5 ± 2.2 mm(3) vs. 48.7 ± 24.9 mm(3) in the control group; P < 0.01). Taken together, our data highlight the possibility that these cannabinoids can prime glioma cells to respond better to ionizing radiation, and suggest a potential clinical benefit for glioma patients by using these two treatment modalities.

Overexpression of protease-activated receptor type 1 (PAR-1) in glioblastoma multiforme WHO IV cells and blood vessels revealed by NCAM-assisted glioblastoma border labeling

Glioblastomas are neuroepithelial tumors with lost cellular differentiation and tenfold increased growth rates compared to low-grade gliomas. Despite of very aggressive treatment options based on surgery, irradiation, and chemotherapy, the prognosis of affected patients has remained poor and showed only slight improvements during the last 30 years. Research on glioblastoma border zone was hindered by the tumor's intense invasion into the brain parenchyma and the lack of suitable tumor cell markers. Nevertheless, the compact tumor mass and tumor invasion zone are composed of distinct cell types that need to be distinguished from each other to be addressed selectively. As the isoform 140 of the neural cell adhesion molecule (NCAM-140) was recently demonstrated to be lost in human gliomas with rising WHO grade, human multiform glioblastomas were characterized as a NCAM-140 negative entity displaying three main distinct invasion patterns. Evaluation of putative therapy targets within the tumor tissue and tumor invasion zone has been made possible through NCAM-140 negativity. In the present study, brain tissue controls and human glioblastoma samples with compact tumor mass and invasion areas were analyzed for their vascularization at the tumor border and the expression of thrombin receptor protease-activated receptor type 1 (PAR-1) within tumor tissue and vascular vessel walls. Use of NCAM-140 enabled the identification of the tumor invasion zone and its experimental investigation. Tissue vascularization was found to be significantly increased in the compact tumor mass of glioblastomas compared to their invasion zone and tumor-free controls with a significantly high and specific overexpression of PAR-1 within tumor cells and within tumor blood vessels depending upon the tumor area. This suggests thereby a functional role of the thrombin receptor PAR-1 in glioma cell malignancy and glioblastoma neoangiogenesis.

Markers of angiogenesis (CD31, CD34, rCBV) and their prognostic value in low-grade gliomas

BACKGROUND AND PURPOSE

Antigens CD31 and CD34 and relative cerebral blood volume (rCBV) in gliomas reflect in different ways neoangiogenesis of the tumour. Thus, we decided: (1) to estimate the correlation between the values of CD31 and CD34 and the value of rCBV in low-grade gliomas (LGG), and (2) to establish the prognostic value of these markers.

MATERIAL AND METHODS

The investigated group consisted of 53 patients with LGG who were operated on in the Neurosurgical Department at Sosnowiec between 2005 and 2011. On the basis of perfusion-weighted imaging (PWI-MRI) in the tumour texture, rCBV was calculated. The values of CD31 and CD34 were estimated on the basis of immunohistochemical investigation. Three outcome measures were assessed: (1) overall survival, (2) progression-free survival, and (3) malignant-free survival. Statistical analyses were done using the STATISTICA 9.0 program.

RESULTS

Higher value of rCBV in the texture of LGG significantly correlated with higher CD31 (p = 0.0006) and CD34 values (p = 0.0043). Progression-free survival was significantly longer in patients with rCBV < 1.75 than for persons with rCBV > 1.75 (p = 0.015). Lower expression of CD31 correlated with probability of longer survival of the patients after the operation of LGG (p = 0.068).

CONCLUSIONS

Density of microvessels as assessed immunohistochemically with CD31+ and CD34+ in LGG correlated with the value of rCBV in the tumour. The value of 1.75 for rCBV may be the threshold for better or poorer outcome of these patients. Expression of CD31 antigen is an important prognostic factor for the time of survival for patients with LGG.

An immunologist's guide to CD31 function in T-cells

Although it is expressed by all leukocytes, including T-, B-lymphocytes and dendritic cells, the immunoglobulin-like receptor CD31 is generally regarded by immunologists as a marker of endothelial cell lineage that lacks an established functional role in adaptive immunity. This perception has recently been challenged by studies that reveal a key role for this molecule in the regulation of T-cell homeostasis, effector function and trafficking. The complexity of the biological functions of CD31 results from the integration of its adhesive and signaling functions in both the immune and vascular systems. Signaling by means of CD31 is induced by homophilic engagement during the interactions of immune cells and is mediated by phosphatase recruitment or activation through immunoreceptor tyrosine inhibitory motifs (ITIMs) that are located in its cytoplasmic tail. Loss of CD31 function is associated with excessive immunoreactivity and susceptibility to cytotoxic killing. Here, we discuss recent findings that have brought to light a non-redundant, complex role for this molecule in the regulation of T-cell-mediated immune responses, with large impact on our understanding of immunity in health and disease.

CD31 is required on CD4+ T cells to promote T cell survival during Salmonella infection

Hematopoietic cells constitutively express CD31/PECAM1, a signaling adhesion receptor associated with controlling responses to inflammatory stimuli. Although expressed on CD4(+) T cells, its function on these cells is unclear. To address this, we have used a model of systemic Salmonella infection that induces high levels of T cell activation and depends on CD4(+) T cells for resolution. Infection of CD31-deficient (CD31KO) mice demonstrates that these mice fail to control infection effectively. During infection, CD31KO mice have diminished numbers of total CD4(+) T cells and IFN-γ-secreting Th1 cells. This is despite a higher proportion of CD31KO CD4(+) T cells exhibiting an activated phenotype and an undiminished capacity to prime normally and polarize to Th1. Reduced numbers of T cells reflected the increased propensity of naive and activated CD31KO T cells to undergo apoptosis postinfection compared with wild-type T cells. Using adoptive transfer experiments, we show that loss of CD31 on CD4(+) T cells alone is sufficient to account for the defective CD31KO T cell accumulation. These data are consistent with CD31 helping to control T cell activation, because in its absence, T cells have a greater propensity to become activated, resulting in increased susceptibility to become apoptotic. The impact of CD31 loss on T cell homeostasis becomes most pronounced during severe, inflammatory, and immunological stresses such as those caused by systemic Salmonella infection. This identifies a novel role for CD31 in regulating CD4 T cell homeostasis.