Temozolomide (TMZ) remains the first-line therapy for glioblastoma (GBM) patients. However, the mechanisms underlying the emergence of acquired TMZ resistance after treatment are unclear. Here, we reveal the critical role of macrophage phagocytosis in GBM recurrence and acquired TMZ resistance. Mechanistically, TMZ treatment sustained GSK3β activation and promoted its interaction with DNMT1. This led to the phosphorylation of DNMT1 at the previously unrecognized S977 site for its K981-dependent ubiquitination and destabilization. The downregulation of DNMT1 leads to hypomethylation of the CD47 promoter and increases the expression of CD47, a key inhibitor of macrophage phagocytosis. Elevated CD47 expression suppresses macrophage phagocytosis and promotes the survival of TMZ-treated GBM cells. The small molecule WIN 51708 disrupts the p-GSK3β-Y216-DNMT1 interaction, which stabilizes DNMT1, decreases CD47 expression, restores phagocytosis in vivo, and resensitizes tumors to TMZ. The GSK3β-DNMT1-CD47 axis was found to be conserved in a TMZ-resistant PDX model and in samples from patients with recurrent GBM, supporting its clinical translational value. Our findings underscore the potential of the combined administration of WIN 51708 and TMZ as a strategy to resensitize GBM tumors.

Less-aggressive lower-grade gliomas (LGGs) frequently transform into glioblastoma (GBM). Most previous studies of gliomas have not focused on LGG-original high-risk subpopulations, which may be one of the most critical hallmarks of glioma progression. In this study, LGG samples are collected to perform single-cell sequencing (scRNA-seq) and identify a unique cell subpopulation marked by CDC20, KIF20A and PTTG1, correlating with poor survival in multiple cohorts. Importantly, the CDC20+KIF20A+PTTG1+ cell subpopulation is strongly associated with transforming LGG to GBM according to scRNA-seq and multiplexed immunofluorescence staining assays. In vitro, ex vivo and in vivo investigations further hint that this cell subpopulation is critical to the proliferation and growth of gliomas, and is associated with the hypoxia core activation. Pharmaceutically and therapeutically, the inhibition of this cell subpopulation showed significant anti-tumor effects and effective enhancement of the Temozolomide treatment efficiency. These findings provide insights into the therapeutic strategies of glioma progression, highlighting promising ways to avoid early-stage gliomas developing into advanced gliomas.

Migrasomes are novel extracellular organelles that were first reported in 2015. The present review summarizes the discovery, structural characteristics, biological functions and relationships of this new cellular organelle with diseases. Migrasomes are annular organelles that extend from the trailing edge of cells during cell migration and are rich in proteins, lipids, nucleic acids and other biomolecules. They serve important roles at multiple levels, including roles in cell‑cell communication, tissue remodeling and immune regulation. The formation and function of migrasomes are associated with the regulation of various molecules and signaling pathways, including nucleation, expansion and maturation. Migrasomes also have important roles in organ morphogenesis, angiogenesis, mitochondrial quality control and immune regulation. In addition, migrasomes are closely associated with the development of various diseases, including kidney diseases, pneumonia after stroke, neurodegenerative diseases and cancer, providing new perspectives and potential targets for disease diagnosis and treatment. For example, in cancer, migrasomes can act as positioning signals, regulating the invasion of liver cancer cells. In neurodegenerative diseases, migrasomes may have a role in clearing damaged mitochondria, thereby helping to alleviate inflammatory responses and cellular dysfunction. Collectively, these findings suggest that migrasomes have notable potential for use in clinical disease diagnosis and treatment.

Hyperactive ribosome biogenesis is a hallmark of tumours. Current ribosome-related studies are concentrated on cancer cells. Ribosomes can regulate both tumour and non-cancer cells within the tumour microenvironment, yet the immunomodulatory effects of cellular ribosome biogenesis blockade remain inadequately understood. We performed ribosome-targeting therapy utilizing CX-5461, an effective and acknowledged selective inhibitor of ribosome biogenesis, in immunocompetent in vivo models and submitted for single-cell RNA sequencing (scRNA-seq). Additional large-scale human scRNA-seq data, in-house clinical samples and assays were used. Ribosome inhibition elevated lymphoid cell cytotoxic granule secretion and macrophage pro-inflammation reprogramming. We uncovered unique immune cell subpopulations that are sensitive to ribosome biogenesis blockade and are associated with adverse clinical outcomes. Impressively, these cells regress during responsive immune checkpoint blockade (ICB) treatment, revealing that they are essential for immunotherapy efficacy. Moreover, targeting ribosomes induces immune checkpoint expression (such as Lag3) and significantly sensitizes tumours to anti-Lag3 immunotherapy, eliciting potent tumour regression and deeper anti-tumour immune responses. These findings unravel previously unrecognized roles of cellular ribosome biogenesis in sustaining immunosuppressive non-cancer cells. Our work unveils that ribosome biogenesis blockade could reinstate immunosurveillance and provide novel strategies to enhance the ICB efficacy in patients with poor immunogenicity.

IntroductionTo establish a new model for exploring the mechanism of the gut microbiome and drug metabolism, we explored whether Taohong Siwu Decoction acts after metabolism by intestinal flora under the premise of clarifying the interaction between intestinal flora and drug metabolism.MethodsTaohong Siwu Decoction (TSD) was fed to germ-free mice and conventional mice, respectively. The serum from both groups of mice was removed and co-cultured with glioma cells in vitro. The co-cultured glioma cells were compared separately for changes at the RNA level using RNA-seq technology. The genes of interest in the comparison results were selected for validation.ResultsThe differences in the phenotypic alterations of glioma cells between serum from TSD-fed germ-free mice and normal mice were statistically significant. In vitro experiments showed that Taohong Siwu Decoction-fed normal mouse serum-stimulated glioma cells, which inhibited proliferation and increased autophagy. RNA-seq analysis showed that TSD-fed normal mouse serum could regulate CDC6 pathway activity in glioma cells. The therapeutic effect of TSD is significantly influenced by intestinal flora.ConclusionThe treatment of tumors by TSD may be modulated by intestinal flora. We established a new method to quantify the relationship between intestinal flora and the regulation of TSD efficacy through this study.

Supplementary Figure from TRAF4 Maintains Deubiquitination of Caveolin-1 to Drive Glioblastoma Stemness and Temozolomide Resistance

Purpose The lncRNA MIR155 host gene (MIR155HG) plays a role in the progression of several malignant cancers. However, the specific mechanisms of MIR155HG in glioma progression have not been clearly established. The purpose of this study was to investigate the function of MIR155HG in glioma at the transcriptome level and relationship with immune infiltration. Patients and Methods Totally, 697 RNA-seq and 594 DNA methylation data were retrieved from The Cancer Genome Atlas (TCGA) dataset while 325 RNA-seq data were retrieved from the Chinese Glioma Genome Atlas (CGGA) dataset. The DNA methylation levels of MIR155HG CpG islands were assessed through bisulfite amplicon sequencing (BSAS). The regulatory mechanism of SP1 on MIR155HG was examined by chromatin immunoprecipitation (ChIP) and luciferase reporter assays. R language was used as the main tool for statistical analysis and graphical work. Results MIR155HG was predominantly expressed in the isocitrate dehydrogenase (IDH) wild-type as well as mesenchymal subtype gliomas. Promoter methylation levels of MIR155HG in glioblastoma (GBM) were remarkably decreased compared with those in lower-grade glioma (LGG). In addition, there were negative correlations between promoter methylation levels and MIR155HG expressions but positive correlations with patients’ overall survival. In vitro studies further revealed that MIR155HG expression was regulated by DNA promoter methylation and transcription factor (SP1) binding to the promoter. Moreover, there was a close association between MIR155HG expression and immune as well as stromal cell infiltrations, inflammatory activities, and immune checkpoints. Clinically, univariate and multivariate Cox analyses revealed that MIR155HG is an independent prognostic marker for glioma patients. Conclusion Our results established that MIR155HG is a potential biomarker for prognosis and an immunotherapeutic target in glioma.