GL-261 (小鼠胶质细胞瘤)（STR鉴定）

The blood–brain barrier is often altered in glioblastoma (GBM) creating a blood–brain–tumor barrier (BBTB) composed of pericytes. The BBTB affects chemotherapy efficacy. However, the expression signatures of BBTB-associated pericytes remain unclear. We aimed to identify BBTB-associated pericytes in single-cell RNA sequencing data of GBM using pericyte markers, a normal brain pericyte expression signature, and functional enrichment. We identified parathyroid hormone receptor-1 (PTH1R) as a potential marker of pericytes associated with BBTB function. These pericytes interact with other cells in GBM mainly through extracellular matrix–integrin signaling pathways. Compared with normal pericytes, pericytes in GBM exhibited upregulation of several ECM genes (including collagen IV and FN1 ), and high expression levels of these genes were associated with a poor prognosis. Cell line experiments showed that PTH1R knockdown in pericytes increased collagen IV and FN1 expression levels. In mice models, the expression levels of PTH1R, collagen IV, and FN1 were consistent with these trends. Evans Blue leakage and IgG detection in the brain tissue suggested a negative correlation between PTH1R expression levels and blood–brain barrier function. Further, a risk model based on differentially expressed genes in PTH1R + pericytes had predictive value for GBM, as validated using independent and in-house cohorts.

Objective Glioblastoma (GBM) has poor clinical prognosis due to limited treatment options. In addition, the current treatment regimens for GBM may only slightly prolong patient survival. The aim of this study was to assess the role of BMAL1 in the immune microenvironment and drug resistance of GBM. Methods GBM cell lines with stable BMAL1 knockdown or LDHA overexpression were constructed, and functionally characterized by the CCK8, EdU incorporation, and transwell assays. In vivo GBM model was established in C57BL/6J mice. Flow cytometry, ELISA, immunofluorescence, and RT-qPCR were performed to detect macrophage polarization. Lactate production, pathological changes, and the expression of glycolytic proteins were analyzed by HE staining, immunohistochemistry, biochemical assays, and Western blotting. Results BMAL1 silencing inhibited the malignant characteristics, lactate production, and expression of glycolytic proteins in GBM cells, and these changes were abrogated by overexpression of LDHA or exogenous lactate supplementation. Furthermore, BMAL1 knockdown induced M1 polarization of macrophages, and inhibited M2 polarization and angiogenesis in GBM cells in conditioned media. Overexpression of LDHA or presence of exogenous lactate inhibited BMAL1-induced M1 polarization and angiogenesis. Finally, BMAL1 silencing and bevacizumab synergistically inhibited glycolysis, angiogenesis and M2 polarization, and promoted M1 polarization in vivo, thereby suppressing GBM growth. Conclusion BMAL1 silencing can sensitize GBM cells to bevacizumab by promoting M1/M2 polarization through the LDHA/lactate axis.

Glioma, marked by a low mutational burden, low immunogenicity, high heterogeneity, and the challenges posed by the blood–brain barrier, continues to be a major hurdle in neuro‐oncology. Current research underscores the necessity for more effective medications and treatment strategies. In this study, we explored the role of Apolipoprotein E (ApoE) in glioma using both bioinformatics and experimental methods. The construction of our bioinformatics risk model identified ApoE as a protective factor linked to longer survival in glioma patients. Subsequently, we created an in situ tumorigenic mouse model and a subcutaneous tumorigenic mouse model with ApoE gene knockout to evaluate the functional impacts of ApoE deficiency in glioma. Our results demonstrated that ApoE deficiency accelerates the growth of glioma and encourages the invasive behaviour of tumour cells into normal brain tissue. Additionally, we detected a reduction in the immune surveillance of glioma in the context of ApoE deficiency. Furthermore, flow cytometry analysis indicated that the lack of ApoE led to a decrease in positive immune cells and an increase in immunosuppressive cells within the tumour microenvironment. Our findings suggest that ApoE plays a crucial role in modulating glioma progression and immune surveillance, highlighting its potential as a therapeutic target.