Brain metastasis is a major cause of death in breast cancer patients. The greatest event for brain metastasis is the breaching of the blood‐brain barrier (BBB) by cancer cells. The role of exosomes in cancer metastasis is clear, whereas the role of exosomes in the integrity of the BBB is unknown. Here, we established a highly brain metastatic breast cancer cell line by three cycles of in vivo selection. The effect of exosomes on the BBB was evaluated in vitro by tracking, transepithelial/transendothelial electrical resistance (TEER), and permeability assays. BBB‐associated exosomal long noncoding RNA (lncRNA) was selected from the GEO dataset and verified by real‐time PCR, TEER, permeability, and Transwell assays. The cells obtained by the in vivo selection showed higher brain metastatic capacity in vivo and higher migration and invasion in vitro compared to the parental cells. Exosomes from the highly brain metastatic cells were internalized by brain microvascular endothelial cells (BMECs), which reduced TEER and increased permeability of BBB. The exosomes derived from the highly metastatic cells promoted invasion of the breast cancer cells in the BBB model. lncRNA GS1‐600G8.5 was highly expressed in the highly brain metastatic cells and their exosomes, as compared to the samples with reduced metastatic behavior. Silencing of GS1‐600G8.5 significantly abrogated the BBB destructive effect of exosomes. GS1‐600G8.5‐deficient exosomes failed to promote the infiltration of cancer cells through the BBB. Furthermore, BMECs treated with GS1‐600G8.5‐deprived exosomes expressed higher tight junction proteins than those treated with the control exosomes. These data suggest the exosomes derived from highly brain metastatic breast cancer cells might destroy the BBB system and promote the passage of cancer cells across the BBB, by transferring lncRNA GS1‐600G8.5.

Background: Aerobic glycolysis plays a key role in tumor metabolic reprogramming to reshape the immune microenvironment. The phosphoglycerate kinase 1 (PGK1) gene codes a glycolytic enzyme that converts 1,3-diphosphoglycerate to 3-phosphoglycerate. However, in lung adenocarcinoma (LUAD), the role of PGK1 in altering the tumor microenvironment (TME) has not yet been determined. Methods: Raw data, including bulk DNA and mRNA-seq data, methylation modification data, single-cell RNA-seq data, proteomics data, clinical case characteristics survival, immunotherapy data, and so on, were obtained from multiple independent public data sets. These data were reanalyzed to uncover the prognosis and immunological characteristics of PGK1 in LUAD. Results: We found that PGK1 mRNA and protein were considerably over-expressed in LUAD compared to normal tissue and that high PGK1 expression is associated with poorer prognostic outcomes in LUAD. The enrichment analysis of PGK1 co-expressed genes in lung adenocarcinoma revealed that PGK1 may be involved in hypoxia, metabolism, DNA synthesis, cell cycle, PI3K/AKT, and various immune and inflammatory signaling pathways. Furthermore, PGK1 is also linked to the recruitment of numerous immune cells, including aDC (dendritic cells), macrophages, and neutrophils. More importantly, PGK1 was highly expressed in immunosuppressive cells, including M2 macrophages, Tregs, and exhausted T cells, among others. Finally, higher PGK1 expression indicated significant correlations to immune checkpoints, TMB (tumor mutation burden), and high response to immunotherapy. Conclusions: The presented findings imply that PGK1, as a glycolysis core gene, may be important for the modification of the immune microenvironment by interacting with the tumor metabolism. The results of this study provide clues for a potential immunometabolic combination therapy strategy in LUAD, for which more experimental and clinical translational research is needed.

Nucleolar and spindle-associated protein 1 (NUSAP1) is a potential molecular marker and intervention target for glioblastoma (GBM). In this study, we aim to investigate upstream regulatory lncRNAs and miRNAs of NUSAP1 through both experimental and bioinformatic methods. We screened upstream lncRNAs and miRNAs of NUSAP1 through multiple databases based on ceRNA theory. Then, in vitro and in vivo experiments were performed to elucidate the relevant biological significance and regulatory mechanism among them. Finally, the potential downstream mechanism was discussed. LINC01393 and miR-128-3p were screened as upstream regulatory molecules of NUSAP1 by TCGA and ENCORI databases. The negative correlations among them were confirmed in clinical specimens. Biochemical studies revealed that overexpression or knockdown of LINC01393 respectively enhanced or inhibited malignant phenotype of GBM cells. MiR-128-3p inhibitor reversed LINC01393 knockdown-mediated impacts on GBM cells. Then, dual-luciferase reporter assay and RNA immunoprecipitation assay were conducted to validate LINC01393/miR-128-3p/NUSAP1 interactions. In vivo, LINC01393-knockdown decreased tumor growth and improved mice survival, while restoration of NUSAP1 partially reversed these effects. Additionally, enrichment analysis and western blot revealed that the roles of LINC01393 and NUSAP1 in GBM progression were associated with NF-κB activation. Our findings showed that LINC01393 sponged miR-128-3p to upregulate NUSAP1, thereby promoting GBM development and progression via activating NF-κB pathway. This work deepens understanding of GBM mechanisms and provides potential novel therapeutic targets for GBM.

Brain metastases (BMs) of lung cancer are common malignant intracranial tumours associated with severe neurological symptoms and an abysmal prognosis. Prostate-specific membrane antigen (PSMA) has been reported to express significantly in a variety of solid tumours. However, the clinical applications of ⁶⁸Ga-PSMA PET/CT and the mechanism of PSMA expression in patients with BMs of lung cancer have rarely been reported. Experiments with ⁶⁸Ga-PSMA PET/CT and immunohistochemical staining were conducted to evaluate the expression of PSMA from seven patients with BMs of lung cancer who accepted surgical treatment in Fudan University Shanghai Cancer Center between October 2020 and October 2021. The mechanism of PSMA expression in BMs of lung cancer was explored by using single-cell RNA sequencing. The median maximum standardized uptake value (SUVmax) in BMs was higher than that in primary lung cancer (8.6 ± 2.8 vs. 3.6 ± 1.3, P < 0.01). The mean SUVmax in BMs was 1.76-fold higher than that in the liver, which indicated the potential of PSMA radioligand therapy (PSMA-RLT) for BMs. BMs showed intense PSMA staining, while normal lung tissue had no PSMA staining and there was only faint primary lung cancer staining by immunohistochemistry (IHC). Single-cell RNA sequencing (scRNA-seq) analysis found that PSMA was mainly expressed in oligodendrocytes of BMs, whereas it was expressed at lower levels in solid cells of lung cancer. PSMA expression in oligodendrocytes might be regulated by the factors ATF3 and NR4A1, which were associated with ER stress.

Brain metastases from lung adenocarcinoma cause significant patient mortality. This study aims to evaluate the role of preoperative Neutrophil-to-Lymphocyte ratio (preNLR) in predicting the survival and prognosis of Lung adenocarcinoma (LUAD) patients with brain metastasis (BM) and provide more references for predicting peritumoral edema. We retrospectively reviewed 125 LUAD-BM patients who had undergone surgical resection from December 2015 to December 2020. The clinical characteristic, demographic, MRI data, and preNLR within 24–48 h before craniotomy were collected. Patients were divided into two groups based on preNLR (high NLR and low NLR), with cutoff values determined by receiver operating characteristic (ROC) analysis. Association between preoperative NLR and clinical features was determined by using Pearson chi-squared tests. Uni- and multivariate analyzes were performed to compare the overall survival (OS) of clinical features. The patients were divided into NLR-low (64 patients) and NLR-high (61 patients) groups based on receiver operating characteristic analysis of NLR area. According to correlation analysis, a high preNLR (NLR≥2.8) is associated with the both supra- and infratentorial location involved (P = 0.017) and a greater incidence of severe peritumoral edema (P = 0.038). By multivariable analysis, age ≥ 65 years (P = 0.011), KPS < 70 (P = 0.043), elevated preNLR (P = 0.013), extracerebral metastases (P = 0.003), EGFR/ALK+ (P = 0.037), postoperative radiotherapy (P = 0.017) and targeted therapy (P = 0.007) were independent prognostic factors. OS nomogram was constructed based on cox model and model performance was examined (AUC = 0.935). PreNLR may serve as a prognosis indicator in LUAD patients with brain metastasis, and high preNLR tends to be positively associate with multiple locations and severe peritumoral edema.