Human gliomas including astrocytomas and oligodendrogliomas are defined as being composed of neoplastic astrocytes and oligodendrocytes respectively. Here, on the basis of in vitro functional assays, we show that gliomas contain a mixture of glial progenitor cells and their progeny. We have set up explant cultures from pilocytic astrocytomas, glioblastomas and oligodendrogliomas and studied antigens that characterize glial lineage, from the precursor cells (glial restricted precursors and oligodendrocyte-type2-astrocyte/oligodendrocyte precursor cells expressing the A2B5 ganglioside) to the differentiated cells (oligodendrocyte and type-1 and type-2 astrocytes). All tumoral explants contain A2B5+ cells and can generate migrating cells with distinctive functional properties according to glioma subtypes. In pilocytic astrocytomas, very few migrating cells are dividing and can differentiate in type-2 astrocytes or towards the oligodendrocyte lineage. In glioblastomas, most migrating cells are dividing, express A2B5 or glial fibrillary acid protein (GFAP) and can generate oligodendrocytes and type-1 and type-2 astrocytes in appropriate medium. Oligodendroglioma explants are made by actively dividing glial precursor cells expressing A2B5 or PSA-NCAM. Only few cells can migrate and differentiation towards oligodendrocyte lineage does not occur. Isolated A2B5+ cells from both glioblastomas and oligodendrogliomas showed similar genetic alterations as the whole tumour. Therefore, pilocytic astrocytomas contain slowly dividing oligodendrocyte-type2-astrocyte/oligodendrocyte precursor cells in keeping with their benign behaviour whereas both glioblastomas and oligodendrogliomas contain neoplastic glial restricted precursor cells. In oligodendrogliomas, these cells are trapped in undifferentiated and proliferating state. The precursor cells properties present in gliomas give new insight into their histogenesis and open up new avenues for research in the field of gliomagenesis.

In order to define specific markers for histogenesis of three well-characterized subgroups of human gliomas (pilocytic astrocytomas, glioblastoma multiforme and oligodendrogliomas), we studied the expression of relevant markers that characterize gliomagenesis, by immunohistochemistry and in situ hybridization. They include the intermediate filament proteins glial fibrillary acidic protein (GFAP), vimentin and nestin, the transcription factors Olig2, Nkx2.2 and Sox10, and the proteolipid protein transcripts plp/dm20. We show that the three major categories of human gliomas express a combinatorial profile of markers that gives new insights to their histogenesis and may help diagnosis. Pilocytic astrocytomas strongly express GFAP, vimentin, Olig2, Nkx2.2 and Sox10 but not nestin. In contrast, glioblastomas strongly express GFAP, vimentin and nestin but these tumours are heterogeneous regarding the expression of the transcription factors studied. Finally, in oligodendrogliomas, intermediate filament proteins are generally not observed whereas Olig2 was found in almost all tumour cells nuclei while only a subpopulation of tumour cells expressed Nkx2.2 and Sox10.

Background Glioblastoma (GBM) is the most common and fatal primary tumor in the central nervous system (CNS). Due to the existence of blood–brain barrier (BBB), most therapeutics cannot efficiently reach tumors in the brain, and as a result, they are unable to be used for effective GBM treatment. Accumulating evidence shows that delivery of therapeutics in form of nanoparticles (NPs) may allow crossing the BBB for effective GBM treatment. Methods Betulinic acid NPs (BA NPs) were synthesized by the standard emulsion approach and characterized by electron microscopy and dynamic light scattering analysis. The resulting NPs were characterized for their anti-tumor effects by cell viability assay, EdU-DNA synthesis assay, cell cycle assay, mitochondrial membrane potential, and PI-FITC apoptosis assay. Further mechanistic studies were carried out through Western Blot and immunostaining analyses. Finally, we evaluated BA NPs in vivo for their pharmacokinetics and antitumor effects in intracranial xenograft GBM mouse models. Results BA NPs were successfully prepared and formed into rod shape. BA NPs could significantly suppress glioma cell proliferation, induce apoptosis, and arrest the cell cycle in the G0/G1 phase in vitro. Furthermore, BA NPs downregulated the Akt/NFκB-p65 signaling pathway in a concentration dependent manner. We found that the observed anti-tumor effect of BA NPs was dependent on the function of CB1/CB2 receptors. Moreover, in the intracranial GBM xenograft mouse models, BA NPs could effectively cross the BBB and greatly prolong the survival time of the mice. Conclusions We successfully synthesized BA NPs, which could cross the BBB and demonstrated a strong anti-tumor effect. Therefore, BA NPs may potentially be used for effective treatment of GBM. Graphical Abstract

Lower-grade glioma (LGG) is a common malignant primary tumour in the central nervous system, and most patients eventually develop highly aggressive gliomas despite comprehensive traditional treatment. Tumour molecular subtypes and prognostic biomarkers play a crucial role in LGG diagnosis and treatment. Therefore, the identification of novel biomarkers in LGG patients is crucial for predicting the prognosis of glioma. Immunogenic cell death (ICD) is defined as regulated cell death that is sufficient to activate the adaptive immune response of immunocompetent hosts. The combination of ICD and immunotherapy might exert a greater and more persistent antitumour effect in gliomas. In our study, we explored the expression, function, and genetic alterations of 34 ICD-related genes. Using 12 ICD-related genes, including IL17RA, IL1R1, EIF2AK3, CD4, PRF1, CXCR3, CD8A, BAX, PDIA3, CASP8, MYD88, and CASP1, we constructed and validated an ICD-related risk signature via least absolute shrinkage and selection operator (LASSO) Cox regression analysis. All the information was obtained from public databases, including The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), and the Chinese Glioma Genome Atlas (CGGA) databases. Our results revealed that ICD-high risk groups have a poor prognosis and might be more sensitive to immune checkpoint blockade (ICB) immunotherapy. In addition, ICD-high risk groups were associated with 1p19q noncodeletion, higher WHO grade, wild type IDH, and an immunosuppressive tumour microenvironment. We verified the prognostic value of 12 ICD-related genes in TCGA and CGGA databases. Immunohistochemistry was performed to verify the expression of several ICD-related genes at the protein level. Our study provides a novel and comprehensive perspective to elucidate the underlying mechanisms of LGG prognosis and direction for future individualized cancer immunotherapy.

WHO 2/3 glioma is a common intracranial tumor that seriously affects the quality of life and survival time of patients. Previous studies have shown that the tricarboxylic acid (TCA) cycle is closely related to the occurrence and development of glioma, while recent studies have shown that cuproptosis, a novel programmed death pathway, is closely related to the inhibition of the TCA cycle. In our study, eight of ten cuproptosis-related genes (CRGs) were found to be differentially expressed between normal and WHO 2/3 glioma tissues. Through the LASSO algorithm, the cuproptosis-associated risk signatures (CARSs) were constructed, which can effectively predict the prognosis of WHO 2/3 glioma patients and are closely related to clinicopathological features. We analyzed the relationship between risk score and immune cell infiltration through Xcell, ssGSEA, TIMER database, and immune checkpoint molecules. In addition, the relationship between risk score and chemotherapeutic drug sensitivity was also investigated. The prognosis-related independent risk factors FDX1 and CDKN2A identified from CARSs are considered potential prognostic biomarkers for WHO 2/3 glioma. The clinical prognosis model based on cuproptosis is expected to provide an effective reference for the diagnosis and treatment of clinical WHO 2/3 glioma patients.