Glioblastoma is the most common and lethal primary intracranial tumor. As the key regulator of tumor cell volume, sodium‐potassium‐chloride cotransporter 1 (NKCC1) expression increases along with the malignancy of the glioma, and NKCC1 has been implicated in glioblastoma invasion. However, little is known about the role of NKCC1 in the epithelial‐mesenchymal transition‐like process in gliomas. We noticed that aberrantly elevated expression of NKCC1 leads to changes in the shape, polarity, and adhesion of cells in glioma. Here, we investigated whether NKCC1 promotes an epithelial–mesenchymal transition (EMT)‐like process in gliomas via the RhoA and Rac1 signaling pathways. Pharmacological inhibition and knockdown of NKCC1 both decrease the expressions of mesenchymal markers, such as N‐cadherin, vimentin, and snail, whereas these treatments increase the expression of the epithelial marker E‐cadherin. These findings indicate that NKCC1 promotes an EMT‐like process in gliomas. The underlying mechanism is the facilitation of the binding of Rac1 and RhoA to GTP by NKCC1, which results in a significant enhancement of the EMT‐like process. Specific inhibition or knockdown of NKCC1 both attenuate activated Rac1 and RhoA, and the pharmacological inhibitions of Rac1 and RhoA both impair the invasion and migration abilities of gliomas. Furthermore, we illustrated that NKCC1 knockdown abolished the dissemination and spread of glioma cells in a nude mouse intracranial model. These findings suggest that elevated NKCC1 activity acts in the regulation of an EMT‐like process in gliomas, and thus provides a novel therapeutic strategy for targeting the invasiveness of gliomas, which might help to inhibit the spread of malignant intracranial tumors.

Autophagy is a vital process that involves degradation of long-lived proteins and dysfunctional organelles and contributes to cellular metabolism. Glioma-initiating cells (GICs) have the ability to self-renew, differentiate into heterogeneous types of tumor cells, and sustain tumorigenicity; thus, GICs lead to tumor recurrence. Accumulating evidence indicates that autophagy can induce stem cell differentiation and increase the lethality of temozolomide against GICs. However, the mechanism underlying the regulation of GIC self-renewal by autophagy remains uncharacterized. In the present study, autophagy induced by AZD8055 and rapamycin treatment suppressed GIC self-renewal in vitro. We found that autophagy inhibited Notch1 pathway activation. Moreover, autophagy activated Notch1 degradation, which is associated with maintenance of the self-renewal ability of GICs. Furthermore, autophagy abolished the tumorigenicity of CD133 + U87-MG neurosphere cells in an intracranial model. These findings suggest that autophagy regulating GICs self-renewal and tumorigenicity is probably bound up with Notch1 degradation. The results of this study could aid in the design of autophagy-based clinical trials for glioma treatments, which may be of great value.

In recent years, research on glioma immunotherapy have grown rapidly. However, the autoimmune‐like side effects that are caused by blocking immunological checkpoints hinder their clinical application in gliomas currently. Galectin‐9, a ligand for T‐cell immunoglobulin mucin 3, has shed a new light on the treatment of malignant glioma. However, the potential mechanism of Galectin‐9 is still under discussion. In this study, first, we methodically gathered 1,027 glioma patients with RNA‐seq and 986 patients with survival data to explore the role and mechanism of Galectin‐9 in gliomas. Second, we analyzed glioma samples from 50 patients in the Department of Neurosurgery, Tianjin Medical University General Hospital. Finally, we found that Galectin‐9 was strongly upregulated in glioblastoma multiforme compared with normal brain tissues and lower‐grade glioma. Patients with Galectin‐9 overexpression had a significantly shorter overall survival. Moreover, the tissue microarray data displayed that the expression of Galectin‐9 in the core of tumor is higher than that in the border and was correlated with the shorter survival in glioma patients. Galectin‐9 is more highly expressed in the mesenchymal subtype of glioblastoma multiforme than in the other subtypes. Simultaneously, Galectin‐9 was closely associated with the immune response and lymphocyte activation, especially T‐cell activation. To further determine the underlying role of Galectin‐9 in the immune response, we selected seven immune metagenes. Through cluster analysis and correlation analysis, we discovered that Galectin‐9 was highly correlated with immune checkpoint molecules and M2 tumor‐associated macrophages. In summary, Galectin‐9 serves as a potential therapeutic target to treat glioblastoma multiforme.

Epidermal growth factor receptor variant III (EGFRvIII) confers growth advantage to glioblastoma multiforme (GBM) and is associated with significantly shorter survival in GBM patients. The interaction between tumor cells and macrophages plays a crucial role in tumor development, supporting angiogenesis, nurturing tumor stem cells, and promoting immune-suppressive TME. Therefore, elucidating the potential mechanisms by which EGFRvIII mutation in GBM cells regulates surrounding immune cells to drive tumor progression may provide new targets for precise immune therapy for specific GBM subtypes or genotypes. In this study, we found that EGFRvIII was the most common form of EGFR mutation, with an incidence rate of 22.13% in glioma patients and 33.3% in GBM patients. Mechanistically, we found for the first time that EGFRvIII-positive GBM secretes high levels of MDK via the ERK-c-Fos signaling pathway. Subsequently, GBM cell-secreted MDK drives macrophage polarization towards the M2 phenotype and secretion of the cytokine CXCL1 via activation of the macrophage surface receptor LRP1 and downstream pathways. In turn, these macrophages secrete CXCL1, which attracts immune-suppressive cells and TAMs to support GBM growth. In the intracranial glioma model, blocking MDK signaling pathway could inhibit macrophage polarization towards the M2 phenotype and tumor malignant progression. In summary, our study for the first time found that EGFRvIII-positive GBM can drive macrophage polarization towards M2 phenotype and secretion of immune-suppressive cytokine CXCL1 via the c-Fos-MDK-LRP1 signaling pathway, providing new targets for precise immune therapy for specific GBM subtypes or genotypes.

Glioblastoma multiforme (GBM) is a fatal cancer with varying life expectancy, even for patients undergoing the same standard therapy. Identification of differentially expressed genes in GBM patients with different survival rates may benefit the development of effective therapeutic strategies. In the present study, key pathways and genes correlated with survival in GBM patients were screened with bioinformatic analysis. Included in the study were 136 eligible patients who had undertaken surgical resection of GBM followed by temozolomide (TMZ) chemoradiation and long-term therapy with TMZ. A total of 383 differentially expressed genes (DEGs) related to GBM survival were identified. Gene Ontology and pathway enrichment analysis as well as hub gene screening and module analysis were performed. As expected, angiogenesis and migration of GBM cells were closely correlated with a poor prognosis. Importantly, the results also indicated that cell dormancy was an essential contributor to the reduced survival of GBM patients. Given the lack of specific targeted genes and pathways known to be involved in tumour cell dormancy, we proposed enriched candidate genes related to the negative regulation of cell proliferation, signalling pathways regulating pluripotency of stem cells and neuroactive ligand-receptor interaction, and 3 hub genes (FTH1, GRM1 and DDIT3). Maintaining persistent cell dormancy or preventing tumour cells from entering dormancy during chemoradiation should be a promising therapeutic strategy.