Gliosarcoma: The Distinct Genomic Alterations Identified by Comprehensive Analysis of Copy Number Variations.

Gliosarcoma (GSM), a histologic variant of glioblastoma (GBM), carries a poor prognosis with less than one year of median survival. Though GSM is similar with GBM in most clinical and pathological symptoms, GBM has unique molecular and histological features. However, as the rarity of GSM samples, the genetic information of this tumor is still lacking. Here, we take a comprehensive analysis of DNA copy number variations (CNV) in GBM and GSM. Whole genome sequencing was performed on 21 cases of GBM and 15 cases of GSM. CNVKIT is used for CNV calling. Our data showed that chromosomes 7, 8, 9, and 10 were the regions where CNV frequently happened in both GBM and GSM. There was a distinct CNV signal in chromosome 2 especially in GSM. The pathway enrichment of genes with CNV was suggested that the GBM and GSM shared the similar mechanism of tumor development. However, the CNV of some screened genes displayed a disparate form between GBM and GSM, such as AMP, BEND2, HDAC6, FOXP3, ZBTB33, TFE3, and VEGFD. It meant that GSM was a distinct subgroup possessing typical biomarkers. The pathways and copy number alterations detected in this study may represent key drivers in gliosarcoma oncogenesis and may provide a starting point toward targeted oncologic analysis with therapeutic potential.

Osimertinib successfully combats EGFR-negative glioblastoma cells by inhibiting the MAPK pathway.

Glioblastoma (GBM) patients have extremely poor prognoses, and currently no effective treatment available including surgery, radiation, and chemotherapy. MAPK-interacting kinases (MNK1/2) as the downstream of the MAPK-signaling pathway regulate protein synthesis in normal and tumor cells. Research has shown that targeting MNKs may be an effective strategy to treat GBM. In this study we investigated the antitumor activity of osimertinib, an FDA-approved epidermal growth factor receptor (EGFR) inhibitor, against patient-derived primary GBM cells. Using high-throughput screening approach, we screened the entire panel of FDA-approved drugs against primary cancer cells derived from glioblastoma patients, found that osimertinib (3 µM) suppressed the proliferation of a subset (10/22) of EGFR-negative GBM cells (>50% growth inhibition). We detected the gene expression difference between osimertinib-sensitive and -resistant cells, found that osimertinib-sensitive GBM cells displayed activated MAPK-signaling pathway. We further showed that osimertinib potently inhibited the MNK kinase activities with IC50 values of 324 nM and 48.6 nM, respectively, against MNK1 and MNK2 kinases; osimertinib (0.3-3 µM) dose-dependently suppressed the phosphorylation of eukaryotic translation initiation factor 4E (eIF4E). In GBM patient-derived xenografts mice, oral administration of osimertinib (40 mg· kg-1 ·d-1, for 18 days) significantly suppressed the tumor growth (TGI = 74.5%) and inhibited eIF4E phosphorylation in tumor cells. Given the fact that osimertinib could cross the blood-brain barrier and its toxicity was well tolerated in patients, our results suggest that osimertinib could be a new and effective drug candidate for the EGFR-negative GBM patients.

HAUSP promoted the growth of glioma cells in vitro and in vivo via stabilizing NANOG.

OBJECTIVE: To investigate the role and mechanisms of HAUSP (Herpesvirus Associated Ubiquitin Specific Protease) and NANOG in pathogenesis of malignant human gliomas progression. METHODS: Lentivirus-mediated HAUSP over-expression and RNAiHAUSP mediated HAUSP down-regulation were established in the glioma cells (U87 and U251 cell lines). Firstly, Real-time qPCR, western-blot (WB) and immunofluorescence staining were performed to detect mRNA levels, protein expressions and deposition of HAUSP and NANOG in the glioma cells, respectively. Then cell proliferation, invasion, apoptosis and xenograft tumor growth in nude mice were assessed by using cell counting kit-8 (CCK-8) assay, transwell assay, flow cytometry (FCM) and Hematoxylin-Eosin (HE) staining. RESULTS: We first demonstrated HAUSP was significantly increased in lentivirus- mediated HAUSP over-expression cells compared to the Control group. HAUSP over-expression could upregulate genes involved in proliferation and invasion such as NANOG. However, the mRNA of NANOG had no significant changes. Similarly, in RNAiHAUSP mediated HAUSP down-regulation group, HAUSP were significantly decreased compared to the Control group. Simultaneously, NANOG protein were decreased significantly, which decreased the proliferation and invasion, increased the apoptosis rate of glioma cells. Finally, low expression of HAUSP could suppress xenograft tumors growth in nude mice in different periods. CONCLUSION: This study revealed that HAUSP-NANOG pathway is a key target to inhibit glioma cells proliferation, and NANOG play important role in the formation and evolution of glioma cells. The regulation of HAUSP could change the biological activity of glioma cells through regulate NANOG expression.

Effects of lentivirus-mediated CYP17A1 gene silencing on the biological activity of glioma.

Gliomas are the most common malignant primary brain tumors with poor prognosis. We attempted to explore the role of CYP17A1 in glioma progression. We demonstrated that the expression of CYP17A1 was significantly higher in the glioma tissues than the normal brain tissues, especially in malignant glioma. Moreover, the expression of CYP17A1 gene was positively correlative with glioma pathological grades. In vitro, CYP17A1 gene silence inhibited the proliferation and invasion of glioma cells and promoted the apoptosis in glioma cells. Also, the subcutaneously transplanted tumour in BALB/C-nu showed that CYP17A1 gene silence inhibited glioma growth. These results reveal that CYP17A1 plays a major role in the progress of glioma.

G-protein-coupled receptor kinase-5 promotes glioblastoma progression by targeting the nuclear factor kappa B pathway.

G-protein-coupled receptor kinase-5 (GRK5) plays essential roles in multiple celluar events. However, its role in the development and progression of glioma is poorly understood. In this research, we found that GRK5 is significantly upregulated in human gliomas. For the first time, a close relationship was noted between GRK5 expression and blood vessel development in human glioma. Specifically co-expression of GRK5 and the tumor stem cell marker CD133 was observed in the cytoplasm of high grade glioma cells. The depletion of GRK5 suppressed the proliferation, migration and invasion in glioma cells, and promoted apoptosis. We next discovered that GRK5 knockdown inhibits the nuclear factor kappa B (NF-κB) pathway, thus resulting in downregulation of key downstream secretory products CCL2, IL-6 and IL-8 in glioma cell conditioned medium (CM). In addition, treatment of cells with the NF-κB stimulator PMA reversed this effect and increased the GRK5 level. Our results demonstrate an oncogenic role for GRK5 and reveal an activation of the GRK5-NF-κB pathway during the malignant progression of glioma.

The long non-coding RNA CRNDE acts as a ceRNA and promotes glioma malignancy by preventing miR-136-5p-mediated downregulation of Bcl-2 and Wnt2.

The colorectal neoplasia differentially expressed (CRNDE) gene encodes a long non-coding RNA (lncRNA) that is the most unregulated among 129 lncRNAs differentially expressed in gliomas. In this study, we confirmed high CRNDE expression in clinical glioma specimens and observed through experiments in human glioma cell lines a novel molecular mechanism by which CRNDE may contribute to glioma pathogenesis. By inducing or silencing CRNDE expression, we detected a positive correlation between CRNDE levels and the proliferative, migratory, and invasive capacities of glioma cells, which were concomitant with a decreased apoptosis rate. Our experiments also suggest that these effects are mediated by downregulation of miR-136-5p, which correlated with the glioma WHO grade. Based on predicted CRNDE/miR-136-5p/mRNA interactions, both the mRNA and protein expression analyses suggested that miR-136-5p-mediated repression of Bcl-2 and Wnt2 underlies the pro-tumoral actions of CRNDE. We therefore propose that CRNDE functions as a competing endogenous RNA (ceRNA) that binds to and negatively regulates miR-136-5p, thereby protecting Bcl-2 and Wnt2 from miR-136-5p-mediated inhibition in glioma.