Project description:To determine which signalling pathways are affected by small RNAs (piRNAs, miRNAs) through target regulation in Glioblastoma Multiforme (GBM), we performed high-throughput next-generation sequencing in U87-MG GBM cell line. The RNA sequencing (RNA-Seq) of small RNAs and transcriptomes discovered both known and novel piRNAs and miRNAs as well other transcriptomes of protein-coding genes, lncRNAs and pseudogenes expressed in this GBM cell line. These small RNAs and target transcriptomes can be further investigated to decode novel molecular mechanisms underlying oncogenesis of this malignancy.
Project description:Glioblastoma (GBM) is a lethal brain tumor without effective treatment options. Data about proteomics in glioma is sparse and it has not yet been integrated into the routine diagnostic work-up or exploited to find potential actionable targets to prevent GBM-induced immune evasion mechanisms and recurrence. We performed proteomic analysis of diffuse glioma samples classified into six subgroups defined by DNA methylation and patient-paired primary and recurrent samples in order to i) provide an inventory of proteins commonly or individually overexpressed in each of the four HGG subgroups compared to the LGG and deduce relevant pathways for each subgroup and ii) identify specific proteins involved in tumor recurrence after surgical removal.
The first study revealed largest differences between low-grade (LGG) and high-grade gliomas (HGG), with major changes observed in proteins involved in active calcium-dependent vesicle trafficking (S100 proteins and annexins), effectors of the immunological synapse, proteins involved in Retinoid acid signalling, and proteins involved in extracellular matrix, cytoskeleton, and cell adhesion. Comparative proteomic analysis between LGG and the HGG subgroups also showed consistency with glioma grading.
The second study identified FcGamma receptors on activated microglia and complement components as major players inducing short relapsing GBM tumors.
In conclusion, specific pathways and proteins represent potential targets to control progression of the distinct subgroups.
Project description:<p><strong>INTRODUCTION:</strong> Neuronal activity regulated by synaptic communication exerts an important role in tumorigenesis and progression in brain tumors. Genes for soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) annotated with the function ‘vesicle’ about synaptic connectivity were identified and one of these proteins, synaptosomal-associated protein 25 (SNAP25), was found to have discrepant expression levels in neuropathies. However, the specific mechanism and prognostic value of SNAP25 during glioma progression remain unclear. </p><p><strong>METHODS:</strong> Using RNA sequencing data from The Cancer Genome Atlas (TCGA) database, the differential synaptosis-related genes between LGG and GBM were identified as highly correlated. Cox proportional hazards regression analysis and survival analysis indicated that the candidate gene SNAP25 could differentiate the outcome of low- and high-risk patients, and the Chinese Glioma Genome Atlas (CGGA) cohort was used for validation of the data set. RT-qPCR, western blot, and immunohistochemistry assays were performed to examine the expression level of SNAP25 in glioma cells and samples. Functional assays were performed to identify the effects of SNAP25 knockdown and overexpression on cell viability, migration, and invasion. Then, an immunofluorescence assay of the xenograft tissue was applied to evaluate the expression of the neuronal dendron formation marker-MAP2. Liquid chromatography-high re solution mass spectrometry (LC-MS)-based metabolomics approach was presented for identifying crucial metabolic disturbances in glioma cells. In situ mouse xenograft model was used to investigate the role of SNAP25 in vivo.</p><p><strong>RESULTS:</strong> SNAP25 was down expressed in glioma tissues and cell lines and low-level SNAP25 indicated an unfavorable prognosis of glioma patients. SNAP25 inhibited cell proliferation, migration, invasion and fostered glutamate metabolism of glioma cells, exerting a tumor suppressor role. SNAP25 overexpression expressed lower expression of MAP2, indicating poor neuronal plasticity and connectivity. SNAP25 could interact with glutaminase(GLS)and GLS knockdown could rescue the anti-tumor effect of SNAP25 in glioma cells. Moreover, upregulation of SNAP25 also decreased tumor volume and prolonged the overall survival (OS) of the xenograft mouse.</p><p><strong>CONCLUSION:</strong> SNAP25 inhibited carcinogenesis of glioma via sponging glutamate metabolism by regulating GLS expression, as well as inhibiting dendritic formation, which could be considered as a molecular target for glioma diagnosis and therapy.</p>