Immunohistochemical comparative analysis of GFAP, MAP - 2, NOGO - A, OLIG - 2 and WT - 1 expression in WHO 2016 classified neuroepithelial tumours and their prognostic value

Expression, Significance, and Correlation of Histone Deacetylase 1/RE-1 Silencing Transcription Factor and Neuronal Markers in Glioma

BACKGROUND

Inducing the differentiation of glioma cells into neuron-like cells may be an effective strategy to combat glioma. The histone deacetylase 1/RE-1 silencing transcription factor (HDAC1/REST) complex regulates the expression of multiple neuronal genes. In this study, we analyzed the presence and significance of this regulatory effect in glioma based on bioinformatics methods.

METHODS

The Human Protein Atlas database was used to obtain immunohistochemical staining images. The Gene Expression Profiling Interactive Analysis and Chinese Glioma Genome Atlas databases were used to analyze the expression of HDAC1/REST and neuronal markers in glioma, their effects on survival, and the association between HDAC1/REST and the expression of neuronal markers and stem cell markers. The differentially expressed genes between the high and low HDAC1/REST groups were explored. The Database for Annotation, Visualization and Integrated Discovery database was used for gene ontology and kyoto encyclopedia of genes and genomes pathway enrichment analysis.

RESULTS

The results showed that the expression of HDAC1 and REST increased with the grade of glioma, while the expression of neuronal markers decreased with the grade of glioma. High expression of HDAC1/REST and low expression of neuronal markers were associated with poor prognosis. HDAC1/REST expression was negatively correlated with the expression of neuronal markers, and positively correlated with the expression of neural stem cell markers. The genes up-regulated in the high HDAC1/REST group were mainly related to extracellular matrix and inflammation, and the down-regulated genes were mainly related to synapsis.

CONCLUSIONS

This study suggested that HDAC1/REST may be involved in maintaining the malignant phenotype of glioma cells and the stem cell status of glioma stem cells by inhibiting the expression of neuronal markers, which promote the progression of glioma.

Immunohistochemical Expression of IDH1, ATRX, Ki67, GFAP, and Prognosis in Indonesian Glioma Patients

Background

The current World Health Organization (WHO) 2021 classification of human glioma is based on key molecular biomarkers to define neoplastic entities. This review further delineates mutant IDH (isocitrate dehydrogenase) from wild-type IDH disease, a necessity given the large survival gap between mutant IDH and wild-type IDH tumors. In Indonesia, there are currently few reports on the distribution and significance of these mutations. Therefore, this research aims to determine the relationship between IDH mutations, as well as clinicopathological and prognostic factors in patients with gliomas. Other immunohistochemical markers including ATRX (alpha-thalassemia/mental retardation, X-linked), Ki67 and GFAP (glial fibrillary acidic protein) expression were also evaluated.

Methods

Forty-two glioma samples were collected from patients who underwent surgery at Dr. Kariadi General Hospital in Semarang, Central Java, Indonesia. Fresh and paraffin-embedded, formalin-fixed tissue samples were removed and sectioned for hematoxylin and eosin staining, immunohistochemistry, and IDH analysis of mutation. Medical records were used to collect clinicopathological and survival data.

Results

IDH1 mutations were discovered in 32 (76,1%) patients, and those with IDH1 mutation had longer overall survival when corresponded to patients with IDH1-wild-type. Lower expression of Ki67 was discovered to be very associated with a better prognosis.

Conclusion

IDH1 mutations status showed a significant relationship with prognosis in patients with glioma. Meanwhile, other markers (ATRX, Ki67, and GFAP) did not correlate with the prognosis.

Case report: Presumptive subcutaneous malignant peripheral nerve sheath tumor with intracranial invasion and osteolysis in the posterior fossa of a dog

A 13-year-old castrated male Toy Poodle presented with an acute vestibular disorder. Magnetic resonance imaging and computed tomography revealed a large oval space-occupying mass with skull destruction located from the subcutaneous tissue to the posterior fossa region. Histopathologically, the mass was a bundled growth of spindle-shaped mesenchymal tumor cells between the myofibrillar and collagen bundles. The cells were moderately irregular in size and had eosinophilic stained cytoplasm. The cells were highly atypical and had rare mitotic figures. Neoplastic cells were immunoreactive for S100, GFAP, Olig-2, SOX10 and immunonegative for NF, E-cadherin, and Claudin-1. Collective findings were presumptive with a diagnosis of malignant peripheral nerve sheath tumor.

Nogo‑A/NgR signaling regulates stemness in cancer stem‑like cells derived from U87MG glioblastoma cells

Neurite outgrowth inhibitor A (Nogo-A), a member of the reticulon 4 family, is an axon regeneration inhibitor that is negatively associated with the malignancy of oligodendroglial tumors. It has been suggested that the Nogo-A/Nogo Receptor (NgR) pathway plays a promoting effect in regulating cancer stem-like cells (CSCs) derived from glioblastoma, indicating that Nogo-A could exert different roles in CSCs than those in parental cancer cells. In the present study, CSCs were generated from the human Uppsala 87 malignant glioma (U87MG) cell line. These U87MG-CSCs were characterized by the upregulation of CD44 and CD133, which are two markers of stemness. The expression levels of Nogo-A and the differentiation of U87MG-CSCs were investigated. In addition, the proliferation, invasion and colony formation U87MG-CSCs were examined. Using culture in serum-containing medium, U87MG-CSCs were differentiated into neuron-like cells specifically expressing MAP2, β-III-tubulin and nestin. Nogo-A was upregulated in U87MG-CSCs compared with parental cells. Knockdown of Nogo-A and inhibition of the Nogo-A/NgR signaling pathway in U87MG-CSCs markedly decreased cell viability, cell cycle entry, invasion and tumor formation, indicating that Nogo-A could regulate U87MG-CSC function. Moreover, Nogo-A was involved in intracellular ATP synthesis and scavenging of accumulated reactive oxygen species. Nogo-A/NgR pathway exerted protective effects against hypoxia-induced non-apoptotic and apoptotic cell death. These results suggest that Nogo-A plays an important role in regulating U87MG-CSCs via the Nogo-A/NgR signaling pathway. Nogo-A may also different roles in U87MG-CSCs compared with their parental cells.

Practice of the new supervised machine learning predictive analytics for glioma patient survival after tumor resection: Experiences in a high-volume Chinese center

OBJECTIVE

This study aims to assess the effectiveness of the Gradient Boosting (GB) algorithm on glioma prognosis prediction and to explore new predictive models for glioma patient survival after tumor resection.

METHODS

A cohort of 776 glioma cases (WHO grades II-IV) between 2010 and 2017 was obtained. Clinical characteristics and biomarker information were reviewed. Subsequently, we constructed the conventional Cox survival model and three different supervised machine learning models, including support vector machine (SVM), random survival forest (RSF), Tree GB, and Component GB. Then, the model performance was compared with each other. At last, we also assessed the feature importance of models.

RESULTS

The concordance indexes of the conventional survival model, SVM, RSF, Tree GB, and Component GB were 0.755, 0.787, 0.830, 0.837, and 0.840, respectively. All areas under the cumulative receiver operating characteristic curve of both GB models were above 0.800 at different survival times. Their calibration curves showed good calibration of survival prediction. Meanwhile, the analysis of feature importance revealed Karnofsky performance status, age, tumor subtype, extent of resection, and so on as crucial predictive factors.

CONCLUSION

Gradient Boosting models performed better in predicting glioma patient survival after tumor resection than other models.

Homeobox B8 Targets Sterile Alpha Motif Domain-Containing Protein 9 and Drives Glioma Progression

Gliomas are the most commonly occurring tumors of the central nervous system. Glioblastoma multiforme (GBM) is the most malignant and aggressive brain cancer in adults. Further understanding of the mechanisms underlying the aggressive nature of GBM is urgently needed. Here we identified homeobox B8 (HOXB8), a member of the homeobox family, as a crucial contributor to the aggressiveness of GBM. Data mining of publicly accessible RNA sequence datasets and our patient cohorts confirmed a higher expression of HOXB8 in the tumor tissue of GBM patients, and a strong positive correlation between the expression level and pathological grading of tumors and a negative correlation between the expression level and the overall survival rate. We next showed that HOXB8 promotes the proliferation and migration of glioblastoma cells and is crucial for the activation of the PI3K/AKT pathway and expression of epithelial-mesenchymal transition-related genes, possibly through direct binding to the promoter of SAMD9 (Sterile Alpha Motif Domain-Containing Protein 9) and activating its transcription. Collectively, we identified HOXB8 as a critical contributor to the aggressiveness of GBM, which provides insights into a potential therapeutic target for GBM and opens new avenues for improving its treatment outcome.

Identification of a Specific Gene Module for Predicting Prognosis in Glioblastoma Patients

Introduction: Glioblastoma (GBM) is the most common and malignant variant of intrinsic glial brain tumors. The poor prognosis of GBM has not significantly improved despite the development of innovative diagnostic methods and new therapies. Therefore, further understanding the molecular mechanism that underlies the aggressive behavior of GBM and the identification of appropriate prognostic markers and therapeutic targets is necessary to allow early diagnosis, to develop appropriate therapies and to improve prognoses.

Methods: We used a weighted gene co-expression network analysis (WGCNA) to construct a gene co-expression network with 524 glioblastoma samples from The Cancer Genome Atlas (TCGA). A risk score was then constructed based on four module genes and the patients' overall survival (OS) rate. The prognostic and predictive accuracy of the risk score were verified in the GSE16011 cohort and the REMBRANDT cohort.

Results: We identified a gene module (the green module) related to prognosis. Then, multivariate Cox analysis was performed on 4 hub genes to construct a Cox proportional hazards regression model from 524 glioblastoma patients. A risk score for predicting survival time was calculated with the following formula based on the top four genes in the green module: risk score = (0.00889 × EXP_CLEC5A) + (0.0681 × EXP_FMOD) + (0.1724 × EXP_FKBP9) + (0.1557 × EXP_LGALS8). The 5-year survival rate of the high-risk group (survival rate: 2.7%, 95% CI: 1.2–6.3%) was significantly lower than that of the low-risk group (survival rate: 8.8%, 95% CI: 5.5–14.1%).

Conclusions: This study demonstrated the potential application of a WGCNA-based gene prognostic model for predicting the survival outcome of glioblastoma patients.

Importance of GFAP isoform-specific analyses in astrocytoma

Gliomas are a heterogenous group of malignant primary brain tumors that arise from glia cells or their progenitors and rely on accurate diagnosis for prognosis and treatment strategies. Although recent developments in the molecular biology of glioma have improved diagnosis, classical histological methods and biomarkers are still being used. The glial fibrillary acidic protein (GFAP) is a classical marker of astrocytoma, both in clinical and experimental settings. GFAP is used to determine glial differentiation, which is associated with a less malignant tumor. However, since GFAP is not only expressed by mature astrocytes but also by radial glia during development and neural stem cells in the adult brain, we hypothesized that GFAP expression in astrocytoma might not be a direct indication of glial differentiation and a less malignant phenotype. Therefore, we here review all existing literature from 1972 up to 2018 on GFAP expression in astrocytoma patient material to revisit GFAP as a marker of lower grade, more differentiated astrocytoma. We conclude that GFAP is heterogeneously expressed in astrocytoma, which most likely masks a consistent correlation of GFAP expression to astrocytoma malignancy grade. The GFAP positive cell population contains cells with differences in morphology, function, and differentiation state showing that GFAP is not merely a marker of less malignant and more differentiated astrocytoma. We suggest that discriminating between the GFAP isoforms GFAPδ and GFAPα will improve the accuracy of assessing the differentiation state of astrocytoma in clinical and experimental settings and will benefit glioma classification.

Sialic acids as cellular markers of immunomodulatory action of dexamethasone on glioma cells of different immunogenicity

Glucocorticosteroids, including dexamethasone (Dex), are commonly used to control tumor-induced edema in the brain tumor patients. There are increasing evidences that immunosuppressive action of Dex interferes with immune surveillance resulting in lower patients overall survival; however, the mechanisms underlying these actions remain unclear. Changes in the expression of sialic acids are critical features of many cancers that reduce their immunogenicity and increase viability. Sialoglycans can be recognized by CD33-related Siglecs that negatively regulate the immune response and thereby impair immune surveillance. In this study, we analysed the effect of Dex on cell surface sialylation pattern and recognition of these structures by Siglec-F receptor in poorly immunogenic GL261 and immunogenic SMA560 glioma cells. Relative amount of α2.3-, α2.6- and α2.8-linked sialic acids were detected by Western blot with MAA (Maackia amurensis) and SNA (Sambucus nigra) lectins, and flow cytometry using monoclonal antibody anti-PSA-NCAM. In response to Dex, α2.8 sialylation in both, GL261 and SMA560 was increased, whereas the level of α2.3-linked sialic acids remained unchanged. Moreover, we found the opposite effects of Dex on α2.6 sialylation in poorly immunogenic and immunogenic glioma cells. Furthermore, changes in sialylation pattern were accompanied by dose-dependent effects of Dex on Siglec-F binding to glioma cell membranes as well as decreased α-neuraminidase activity. These results suggest that glucocorticosteroid-induced alterations in cell surface sialylation and Siglecs recognition may dampen anti-tumor immunity, and participate in glioma-promoting process by immune cells. Our study gives new view on corticosteroid therapy in glioma patients.