Gliomas are the most common primary neuroepithelial tumors of the central nervous system in adults, of which glioblastoma is the deadliest subtype. Apart from the intrinsically indestructible characteristics of glioma (stem) cells, accumulating evidence suggests that the tumor microenvironment also plays a vital role in the refractoriness of glioblastoma. The primary functions of platelets are to stop bleeding and regulate thrombosis under physiological conditions. Furthermore, platelets are also active elements that participate in a variety of processes of tumor development, including tumor growth, invasion, and chemoresistance. Glioma cells recruit and activate resting platelets to become tumor-educated platelets (TEPs), which in turn can promote the proliferation, invasion, stemness, and chemoresistance of glioma cells. TEPs can be used to obtain genetic information about gliomas, which is helpful for early diagnosis and monitoring of therapeutic effects. Platelet membranes are intriguing biomimetic materials for developing efficacious drug carriers to enhance antiglioma activity. Herein, we review the recent research referring to the contribution of platelets to the malignant characteristics of gliomas and focusing on the molecular mechanisms mediating the interaction between TEPs and glioma (stem) cells, as well as present the challenges and opportunities in targeting platelets for glioma therapy.
Humans ; Glioma/metabolism* ; Blood Platelets/physiology* ; Brain Neoplasms/pathology* ; Tumor Microenvironment

Humans ; Glioma/metabolism* ; Consensus ; China ; Brain Neoplasms/pathology* ; Pathology, Molecular

Objective To investigate the expression and correlation of LY86-AS1 and KHDRBS2 in glioblastoma (GBM), and their impacts on the prognosis of patients and immune cell infiltration. Methods Based on the GSE50161 dataset from the Gene Expression Omnibus (GEO) database, LY86-AS1 and KHDRBS2, which are closely related to the development of GBM, were identified by WGCNA and differential expression analysis. The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA) databases were used to analyze the relationship between the expression of LY86-AS1 and KHDRBS2 and the prognosis of GBM patients. Multiple datasets were employed to analyze the correlation between the expression levels of LY86-AS1 and KHDRBS2 and its relationship with immune cell infiltration. Real-time quantitative PCR was used to verify the expression of LY86-AS1 and KHDRBS2 in GBM and normal brain tissues. The Human Protein Atlas (HPA) database was accessed to obtain the protein expression of KHDRBS2, and immunohistochemical staining was conducted to verify the protein expression of KHDRBS2. Results LY86-AS1 and KHDRBS2 were lowly expressed in GBM tissues and were closely related to the development of GBM, showing a significant positive correlation. Patients with low expression levels of LY86-AS1 and KHDRBS2 had a lower overall survival rate than those with high expression levels. LY86-AS1 was positively correlated with naive B cells, plasma cells, activated NK cells, M1 macrophages, activated mast cells and monocytes. KHDRBS2 was positively correlated with naive B cells, plasma cells, helper T cells, activated NK cells and monocytes. Conclusion The low expression levels of LY86-AS1 and KHDRBS2 in GBM, which is associated with poor prognosis, affect the tumor immune microenvironment and may serve as potential new biomarkers for the diagnosis of GBM and the prognosis assessment of patients.
Humans ; Glioblastoma/metabolism* ; Prognosis ; Brain Neoplasms/pathology* ; Gene Expression Regulation, Neoplastic ; RNA-Binding Proteins/metabolism*

OBJECTIVES: To investigate the mechanism by which circ_EPHB4 regulates temozolomide (TMZ) sensitivity of glioma cells through the miR-424-5p/Wnt3 signal axis. METHODS: We detected the expression levels of circ_EPHB4, miR-424-5p and Wnt3 mRNA in glioma specimens from 25 patients with primary glioma and 25 patients experiencing relapse following temozolomide-based chemotherapy and in TMZ-sensitive and -resistant glioma A172 and SHG44 cells with circ_EPHB4 knockdown using qRT-PCR, and Wnt3 protein expression level was detected with Western blotting. Cell viability, colony-forming ability, and apoptosis of the cells with circ_EPHB4 knockdown were assessed, and the targeted regulation relationship between circ_EPHB4, miR-424-5p, and Wnt3 was verified by dual luciferase reporter assay and RNA immunoprecipitation (RIP) experiments. The effect of circ_EPHB4 knockdown on tumorigenesis of glioma cells was evaluated in subcutaneous tumor-bearing nude mouse models. RESULTS: The expression of circ_EPHB4 was significantly increased in glioma tissues and cells as compared with normal neural tissues and astrocytes (P=0.014). In TMZ-resistant glioma cells, circ_EPHB4 knockdown resulted in an obvious reduction of IC50 value of TMZ, inhibited cell colony formation, and promoted cell apoptosis, and these effects were reversed by miR-424-5p knockdown. The expressions of miR-424-5p and circ_EPHB4 were negatively correlated in glioma tissues (P=0.011). MiR-424-5p knockdown also attenuated the effect of circ_EPHB4 knockdown on expressions of PCNA, P-gp, MRP1 and bax. CONCLUSIONS Circ_EPHB4 regulates Wnt3 expression through "sponge adsorption" of miR-424-5p, thereby modulating TMZ-resistant glioblastoma cell clonogenesis, apoptosis, and TMZ sensitivity, suggesting the potential of circ_EPHB4 as a therapeutic target for reversing drug resistance of gliomas.
MicroRNAs/genetics* ; Humans ; Temozolomide ; Glioma/genetics* ; Animals ; Mice, Nude ; Cell Line, Tumor ; Wnt3 Protein/metabolism* ; Mice ; Apoptosis ; RNA, Circular ; Drug Resistance, Neoplasm ; Brain Neoplasms/pathology* ; Signal Transduction

Hypoxia, as an important hallmark of the tumor microenvironment, is a major cause of oxidative stress and plays a central role in various malignant tumors, including glioblastoma. Elevated reactive oxygen species (ROS) in a hypoxic microenvironment promote glioblastoma progression; however, the underlying mechanism has not been clarified. Herein, we found that hypoxia promoted ROS production, and the proliferation, migration, and invasion of glioblastoma cells, while this promotion was restrained by ROS scavengers N-acetyl-L-cysteine (NAC) and diphenyleneiodonium chloride (DPI). Hypoxia-induced ROS activated hypoxia-inducible factor-1α (HIF-1α) signaling, which enhanced cell migration and invasion by epithelial-mesenchymal transition (EMT). Furthermore, the induction of serine protease inhibitor family E member 1 (SERPINE1) was ROS-dependent under hypoxia, and HIF-1α mediated SERPINE1 increase induced by ROS via binding to the SERPINE1 promoter region, thereby facilitating glioblastoma migration and invasion. Taken together, our data revealed that hypoxia-induced ROS reinforce the hypoxic adaptation of glioblastoma by driving the HIF-1α-SERPINE1 signaling pathway, and that targeting ROS may be a promising therapeutic strategy for glioblastoma.
Humans ; Cell Hypoxia ; Cell Line, Tumor ; Glioblastoma/pathology* ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Plasminogen Activator Inhibitor 1/metabolism* ; Reactive Oxygen Species/metabolism* ; Signal Transduction ; Tumor Microenvironment ; Brain Neoplasms/pathology*

Glioma is the most common and lethal intrinsic primary tumor of the brain. Its controversial origins may contribute to its heterogeneity, creating challenges and difficulties in the development of therapies. Among the components constituting tumors, glioma stem cells are highly plastic subpopulations that are thought to be the site of tumor initiation. Neural stem cells/progenitor cells and oligodendrocyte progenitor cells are possible lineage groups populating the bulk of the tumor, in which gene mutations related to cell-cycle or metabolic enzymes dramatically affect this transformation. Novel approaches have revealed the tumor-promoting properties of distinct tumor cell states, glial, neural, and immune cell populations in the tumor microenvironment. Communication between tumor cells and other normal cells manipulate tumor progression and influence sensitivity to therapy. Here, we discuss the heterogeneity and relevant functions of tumor cell state, microglia, monocyte-derived macrophages, and neurons in glioma, highlighting their bilateral effects on tumors. Finally, we describe potential therapeutic approaches and targets beyond standard treatments.
Humans ; Glioma/metabolism* ; Neuroglia/metabolism* ; Carcinogenesis/pathology* ; Neural Stem Cells/metabolism* ; Microglia/metabolism* ; Brain Neoplasms/metabolism* ; Tumor Microenvironment

Glioblastoma multiforme (GBM), a highly malignant and heterogeneous brain tumor, contains various types of tumor and non-tumor cells. Whether GBM cells can trans-differentiate into non-neural cell types, including mural cells or endothelial cells (ECs), to support tumor growth and invasion remains controversial. Here we generated two genetic GBM models de novo in immunocompetent mouse brains, mimicking essential pathological and molecular features of human GBMs. Lineage-tracing and transplantation studies demonstrated that, although blood vessels in GBM brains underwent drastic remodeling, evidence of trans-differentiation of GBM cells into vascular cells was barely detected. Intriguingly, GBM cells could promiscuously express markers for mural cells during gliomagenesis. Furthermore, single-cell RNA sequencing showed that patterns of copy number variations (CNVs) of mural cells and ECs were distinct from those of GBM cells, indicating discrete origins of GBM cells and vascular components. Importantly, single-cell CNV analysis of human GBM specimens also suggested that GBM cells and vascular cells are likely separate lineages. Rather than expansion owing to trans-differentiation, vascular cell expanded by proliferation during tumorigenesis. Therefore, cross-lineage trans-differentiation of GBM cells is very unlikely to occur during gliomagenesis. Our findings advance understanding of cell lineage dynamics during gliomagenesis, and have implications for targeted treatment of GBMs.
Mice ; Animals ; Humans ; Glioblastoma/pathology* ; Endothelial Cells/pathology* ; DNA Copy Number Variations ; Brain/metabolism* ; Brain Neoplasms/pathology*

Objective: To investigate the clinicopathological characteristics, pathological diagnosis and prognosis of diffuse midline glioma (DMG) with H3K27 alteration in adults. Methods: Twenty cases of H3K27-altered adult DMG diagnosed in the First Affiliated Hospital of Nanjing Medical University were enrolled from 2017 to 2022. All cases were evaluated by clinical and imaging presentations, HE, immunohistochemical staining and molecular genetics; and the relevant literature was reviewed. Results: The ratio of male to female was 1∶1, and the median age was 53 years (range from 25 to 74 years); the tumors were located in the brainstem (3/20, 15%) and non-brainstem (17/20, 85%; three in thoracolumbar spinal cord and one in pineal region). The clinical manifestations were non-specific, mostly dizziness, headache, blurred vision, memory loss, low back pain, limb sensation and/or movement disorders, etc. Microscopically, the tumors showed infiltrative growth, with WHO grade 2 (3 cases), grade 3 (12 cases), and grade 4 (5 cases). The tumors showed astrocytoma-like and oligdendroglioma-like, pilocytic astrocytoma-like and epithelioid-like patterns. Immunohistochemically, the tumor cells were positive for GFAP, Olig2 and H3K27M, and H3K27me3 expression was variably lost. ATRX expression was lost in four cases, p53 was strongly positive in 11 cases. Ki-67 index was about 5%-70%. Molecular genetics showed p. k27m mutation in exon 1 of H3F3A gene in 20 cases; BRAF mutation in two cases: V600E and L597Q mutation in one case each. Follow up intervals ranged from 1 to 58 months, and the survival time for brainstem (6.0 months) and non-brainstem (30.4 months) tumors was significantly different (P<0.05). Conclusions: DMG with H3K27 alteration is uncommonly found in adults, mostly occurs in non-brainstem, and can present in adults of all ages. Owing to the wide histomorphologic features, mainly astrocytic differentiation, routine detection of H3K27me3 in midline glioma is recommended. Molecular testing should be performed on any suspected cases to avoid missed diagnosis. Concomitant BRAF L597Q mutation and PPM1D mutation are novel findings. The overall prognosis of this tumor is poor, with tumors located in the brainstem showing worse outcome.
Humans ; Adult ; Male ; Female ; Middle Aged ; Aged ; Histones/genetics* ; Brain Neoplasms/pathology* ; Proto-Oncogene Proteins B-raf/metabolism* ; Glioma/pathology* ; Astrocytoma/pathology* ; Mutation

OBJECTIVE: To investigate the effect of lactic acid-induced upregulation of PLEKHA4 expression on biological behaviors of glioma cells and the possible molecular mechanism. METHODS: GEO database and GEPIA2 website were used to analyze the relationship between PLEKHA4 expression level and the pathological grade of glioma. A specific PLEKHA4 siRNA was transfected in glioma U251 and T98G cells, and the changes in cell proliferation ability were assessed by real-time cell analysis technology and Edu experiment. The colony-forming ability of the cells was evaluated using plate cloning assay, and cell cycle changes and cell apoptosis were analyzed with flow cytometry. The mRNA expression of PLEKHA4 was detected by PCR in glioma samples and controls and in glioma cells treated with lactic acid and glucose. Xenograft mice in vivo was used to detect tumor formation in nude mice; Western blotting was used to detect the expressions of cyclinD1, CDK2, Bcl2, β-catenin and phosphorylation of the key proteins in the MAPK signaling pathway. RESULTS: The results of GEO database and online website analysis showed that PLEKHA4 was highly expressed in glioma tissues and was associated with poor prognosis; PLEKHA4 knockdown obviously inhibited the proliferation and attenuated the clone-forming ability of the glioma cells (P < 0.05). Flow cytometry showed that PLEKHA4 knockdown caused cell cycle arrest in G1 phase and promoted apoptosis of the cells (P < 0.01). PLEKHA4 gene mRNA expression was increased in glioma samples and glioma cells after lactate and glucose treatment (P < 0.01). PLEKHA4 knockdown, tumor formation ability of nude mice decreased; PLEKHA4 knockdown obviously lowered the expression of cyclinD1, CDK2, Bcl2 and other functional proteins, inhibited the phosphorylation of ERK and p38 and reduced the expression of β-catenin protein (P < 0.01). CONCLUSION PLEKHA4 knockdown inhibited the proliferation of glioma cells and promoted apoptosis by inhibiting the activation of the MAPK signaling pathway and expression of β-catenin. Lactic acid produced by glycolysis upregulates the expression of PLEKHA4 in glioma cells.
Humans ; Animals ; Mice ; Up-Regulation ; beta Catenin/metabolism* ; Mice, Nude ; Brain Neoplasms/pathology* ; Lactic Acid ; Cell Line, Tumor ; Glioma/pathology* ; Cell Proliferation ; Apoptosis ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; RNA, Messenger/genetics* ; Gene Expression Regulation, Neoplastic

Detailed characterizations of genomic alterations have not identified subtype-specific vulnerabilities in adult gliomas. Mapping gliomas into developmental programs may uncover new vulnerabilities that are not strictly related to genomic alterations. After identifying conserved gene modules co-expressed with EGFR or PDGFRA (EM or PM), we recently proposed an EM/PM classification scheme for adult gliomas in a histological subtype- and grade-independent manner. By using cohorts of bulk samples, paired primary and recurrent samples, multi-region samples from the same glioma, single-cell RNA-seq samples, and clinical samples, we here demonstrate the temporal and spatial stability of the EM and PM subtypes. The EM and PM subtypes, which progress in a subtype-specific mode, are robustly maintained in paired longitudinal samples. Elevated activities of cell proliferation, genomic instability and microenvironment, rather than subtype switching, mark recurrent gliomas. Within individual gliomas, the EM/PM subtype was preserved across regions and single cells. Malignant cells in the EM and PM gliomas were correlated to neural stem cell and oligodendrocyte progenitor cell compartment, respectively. Thus, while genetic makeup may change during progression and/or within different tumor areas, adult gliomas evolve within a neurodevelopmental framework of the EM and PM molecular subtypes. The dysregulated developmental pathways embedded in these molecular subtypes may contain subtype-specific vulnerabilities.
Humans ; Brain Neoplasms/pathology* ; Neoplasm Recurrence, Local/metabolism* ; Glioma/pathology* ; Neural Stem Cells/pathology* ; Oligodendrocyte Precursor Cells/pathology* ; Tumor Microenvironment