Mesenchymal Transformation: The Rosetta Stone of Glioblastoma Pathogenesis and Therapy Resistance

Insights of immune cell heterogeneity, tumor-initiated subtype transformation, drug resistance, treatment and detecting technologies in glioma microenvironment

BACKGROUND

With the gradual understanding of glioma development and the immune microenvironment, many immune cells have been discovered. Despite the growing comprehension of immune cell functions and the clinical application of immunotherapy, the precise roles and characteristics of immune cell subtypes, how glioma induces subtype transformation of immune cells and its impact on glioma progression have yet to be understood.

AIM OF THE REVIEW

In this review, we comprehensively center on the four major immune cells within the glioma microenvironment, particularly neutrophils, macrophages, lymphocytes, myeloid-derived suppressor cells (MDSCs), and other significant immune cells. We discuss (1) immune cell subtype markers, (2) glioma-induced immune cell subtype transformation, (3) the mechanisms of each subtype influencing chemotherapy resistance, (4) therapies targeting immune cells, and (5) immune cell-associated single-cell sequencing. Eventually, we identified the characteristics of immune cell subtypes in glioma, comprehensively summarized the exact mechanism of glioma-induced immune cell subtype transformation, and concluded the progress of single-cell sequencing in exploring immune cell subtypes in glioma.

KEY SCIENTIFIC CONCEPTS OF REVIEW

In conclusion, we have analyzed the mechanism of chemotherapy resistance detailly, and have discovered prospective immunotherapy targets, excavating the potential of novel immunotherapies approach that synergistically combines radiotherapy, chemotherapy, and surgery, thereby paving the way for improved immunotherapeutic strategies against glioma and enhanced patient outcomes.

Purine metabolism rewiring improves glioblastoma susceptibility to temozolomide treatment

Glioblastoma (GBM) is among the deadliest cancers, characterized by poor prognosis and median survival of 12-15 months post-diagnosis. Despite aggressive therapeutic regimens, GBM treatment is still an unmet clinical need due to heterogeneity, recurrencies, and resistance. Metabolic reshaping is emerging as a critical mechanism supporting cell proliferation and sustaining chemoresistance. In this study, we explored metabolic changes induced by chemotherapy in temozolomide (TMZ)-sensitive and TMZ-resistant GBM cell lines. We found that purine levels were altered in sensitive versus resistant GBM cells, highlighting a critical role of guanosine and inosine metabolism. By using a mesenchymal-like GBM zebrafish model, we uncovered dysregulated pathways involved in purine metabolism, with a downregulation of catabolic processes. Our data indicate that combined treatment with TMZ plus guanosine and inosine increased cytotoxicity, enhancing chemotherapy effectiveness in TMZ-resistant cells. These effects correlated with alterations in mitochondrial dynamics and activity. Specifically, the combinatorial effectiveness of TMZ with guanosine and inosine was linked to Mitofusin-2 overexpression, enhancing mitochondrial fusion, typically associated with a better prognosis. Therefore, our findings suggest that purine metabolism is involved in the metabolic rewiring of TMZ-resistant cells, suggesting guanosine and inosine as potential adjuvant treatments to improve the cytotoxicity effects of chemotherapy in resistant GBM.

ARHGAP12 and ARHGAP29 exert distinct regulatory effects on switching between two cell morphological states through GSK-3 activity

Cancer cells undergo morphological changes and phenotype switching to promote invasion into healthy tissues. Manipulating the transitional morphological states in cancer cells to prevent tumor dissemination may enhance survival and improve treatment response. We describe two members of the RhoGTPase activating protein (ARHGAP) family, ARHGAP12 and ARHGAP29, as regulators of transitional morphological states in glioma via Src kinase signaling events, leading to morphological changes that correspond to phenotype switching. Moreover, we establish a link between glycogen synthase kinase 3 (GSK-3) inhibition and β-catenin translocation in altering transcription of ARHGAP12 and ARHGAP29. Silencing ARHGAP12 causes loss of N-cadherin and adoption of mesenchymal morphology, a characteristic feature of aggressive cellular behavior. In patients with glioblastoma (GBM), we identify a link between ARHGAP12 and ARHGAP29 co-expression and recurrence after treatment. Consequently, we propose that further investigation of how ARHGAPs regulate transitional morphological events to drive cancer dissemination is warranted.

Understanding Neovascularization in Glioblastoma: Insights from the Current Literature

Glioblastomas (GBMs), among the most aggressive and resilient brain tumors, characteristically exhibit high angiogenic potential, leading to the formation of a dense yet aberrant vasculature, both morphologically and functionally. With these premises, numerous expectations were initially placed on anti-angiogenic therapies, soon dashed by their limited efficacy in concretely improving patient outcomes. Neovascularization in GBM soon emerged as a complex, dynamic, and heterogeneous process, hard to manage with the classical standard of care. Growing evidence has revealed the existence of numerous non-canonical strategies of angiogenesis, variously exploited by GBM to meet its ever-increasing metabolic demand and differently involved in tumor progression, recurrence, and escape from treatments. In this review, we provide an accurate description of each neovascularization mode encountered in GBM tumors to date, highlighting the molecular players and signaling cascades primarily involved. We also detail the key architectural and functional aspects characteristic of the GBM vascular compartment because of an intricate crosstalk between the different angiogenic networks. Additionally, we explore the repertoire of emerging therapies against GBM that are currently under study, concluding with a question: faced with such a challenging scenario, could combined therapies, tailored to the patient's genetic signatures, represent an effective game changer?

Blocking ITGA5 potentiates the efficacy of anti-PD-1 therapy on glioblastoma by remodeling tumor-associated macrophages

BACKGROUND

Glioblastoma (GBM) is largely refractory to antibodies against programmed cell death 1 (anti-PD-1) therapy. Fully understanding the cellular heterogeneity and immune adaptations in response to anti-PD-1 therapy is necessary to design more effective immunotherapies for GBM. This study aimed to dissect the molecular mechanisms of specific immunosuppressive subpopulations to drive anti-PD-1 resistance in GBM.

METHODS

We systematically analysed single-cell RNA sequencing and spatial transcriptomics data from GBM tissues receiving anti-PD-1 therapy to characterize the microenvironment alterations. The biological functions of a novel circular RNA (circRNA) were validated both in vitro and in vivo. Mechanically, co-immunoprecipitation, RNA immunoprecipitation and pull-down assays were conducted.

RESULTS

Mesenchymal GBM (MES-GBM) cells, which were associated with a poor prognosis, and secreted phosphoprotein 1 (SPP1)+ myeloid-derived macrophages (SPP1+ MDMs), a unique subpopulation of MDMs with complex functions, preferentially accumulated in non-responders to anti-PD-1 therapy, indicating that MES-GBM cells and SPP1+ MDMs were the main anti-PD-1-resistant cell subpopulations. Functionally, we determined that circular RNA succinate dehydrogenase complex assembly factor 2 (circSDHAF2), which was positively associated with the abundance of these two anti-PD-1-resistant cell subpopulations, facilitated the formation of a regional MES-GBM and SPP1+ MDM cell interaction loop, resulting in a spatially specific adaptive immunosuppressive microenvironment. Mechanically, we found that circSDHAF2 promoted MES-GBM cell formation by stabilizing the integrin alpha 5 (ITGA5) protein through N-glycosylation. Meanwhile, the N-glycosylation of the ITGA5 protein facilitated its translocation into exosomes and subsequent delivery to MDMs to induce the formation of SPP1+ MDMs, which in turn maintained the MES-GBM cell status and induced T-cell dysfunction via the SPP1-ITGA5 pathway, ultimately promoting GBM immune escape. Importantly, our findings demonstrated that antibody-mediated ITGA5 blockade enhanced anti-PD-1-mediated antitumor immunity.

CONCLUSIONS

This work elucidated the potential tissue adaptation mechanism of intratumoral dynamic interactions between MES-GBM cells, MDMs and T cells in anti-PD-1 non-responders and identified the therapeutic potential of targeting ITGA5 to reduce anti-PD-1 resistance in GBM.

Integrating Metabolic RNA Labeling-Based Time-Resolved Single-Cell RNA Sequencing with Spatial Transcriptomics for Spatiotemporal Transcriptomic Analysis

Metabolic RNA labeling-based time-resolved single-cell RNA sequencing (scRNA-seq) has provided unprecedented tools to dissect the temporal dynamics and the complex gene regulatory networks of gene expression. However, this technology fails to reveal the spatial organization of cells in tissues, which also regulates the gene expression by intercellular communication. Herein, it is demonstrated that integrating time-resolved scRNA-seq with spatial transcriptomics is a new paradigm for spatiotemporal analysis. Metabolic RNA labeling-based time-resolved Well-TEMP-seq is first applied to profile the transcriptional dynamics of glioblastoma (GBM) cells and discover two potential pathways of EZH2-mediated mesenchymal transition in GBM. With spatial transcriptomics, it is further revealed that the crosstalk between CCL2+ malignant cells and IL10+ tumor-associated macrophages in the tumor microenvironment through an EZH2-FOSL2-CCL2 axis contributes to the mesenchymal transition in GBM. These discoveries show the power of integrative spatiotemporal scRNA-seq to elucidate the complex gene regulatory mechanism and advance the understanding of cellular processes in disease.

Targeting metabolic reprogramming in glioblastoma as a new strategy to overcome therapy resistance

Glioblastoma (GBM) is one of the deadliest tumors due to its high aggressiveness and resistance to standard therapies, resulting in a dismal prognosis. This lethal tumor carries out metabolic reprogramming in order to modulate specific pathways, providing metabolites that promote GBM cells proliferation and limit the efficacy of standard treatments. Indeed, GBM remodels glucose metabolism and undergoes Warburg effect, fuelling glycolysis even when oxygen is available. Moreover, recent evidence revealed a rewiring in nucleotide, lipid and iron metabolism, resulting not only in an increased tumor growth, but also in radio- and chemo-resistance. Thus, while on the one hand metabolic reprogramming is an advantage for GBM, on the other hand it may represent an exploitable target to hamper GBM progression. Lately, a number of studies focused on drugs targeting metabolism to uncover their effects on tumor proliferation and therapy resistance, demonstrating that some of these are effective, in combination with conventional treatments, sensitizing GBM to radiotherapy and chemotherapy. However, GBM heterogeneity could lead to a plethora of metabolic alterations among subtypes, hence a metabolic treatment might be effective for proneural tumors but not for mesenchymal ones, which are more aggressive and resistant to conventional approaches. This review explores key mechanisms of GBM metabolic reprogramming and their involvement in therapy resistance, highlighting how metabolism acts as a double-edged sword for GBM, taking into account metabolic pathways that seem to offer promising treatment options for GBM.

Molecular principles underlying aggressive cancers

Aggressive tumors pose ultra-challenges to drug resistance. Anti-cancer treatments are often unsuccessful, and single-cell technologies to rein drug resistance mechanisms are still fruitless. The National Cancer Institute defines aggressive cancers at the tissue level, describing them as those that spread rapidly, despite severe treatment. At the molecular, foundational level, the quantitative biophysics discipline defines aggressive cancers as harboring a large number of (overexpressed, or mutated) crucial signaling proteins in major proliferation pathways populating their active conformations, primed for their signal transduction roles. This comprehensive review explores highly aggressive cancers on the foundational and cell signaling levels, focusing on the differences between highly aggressive cancers and the more treatable ones. It showcases aggressive tumors as harboring massive, cancer-promoting, catalysis-primed oncogenic proteins, especially through certain overexpression scenarios, as predisposed aggressive tumor candidates. Our examples narrate strong activation of ERK1/2, and other oncogenic proteins, through malfunctioning chromatin and crosslinked signaling, and how they activate multiple proliferation pathways. They show the increased cancer heterogeneity, plasticity, and drug resistance. Our review formulates the principles underlying cancer aggressiveness on the molecular level, discusses scenarios, and describes drug regimen (single drugs and drug combinations) for PDAC, NSCLC, CRC, HCC, breast and prostate cancers, glioblastoma, neuroblastoma, and leukemia as examples. All show overexpression scenarios of master transcription factors, transcription factors with gene fusions, copy number alterations, dysregulation of the epigenetic codes and epithelial-to-mesenchymal transitions in aggressive tumors, as well as high mutation loads of vital upstream signaling regulators, such as EGFR, c-MET, and K-Ras, befitting these principles.

Sex differences in the molecular profile of adult diffuse glioma are shaped by IDH status and tumor microenvironment

BACKGROUND

Sex differences in adult diffuse glioma (ADG) are well established clinically, yet the underlying molecular mechanisms remain inadequately understood. Here, we aim to reveal molecular features and cellular compositions unique to each sex in ADG to comprehend the role of sex in disease etiology.

METHODS

We quantified sex differences in the transcriptome of ADG using multiple independent glioma patient datasets. Next, we delved into the single-cell landscape to examine sex differences in gene expression and cellular composition. To explore how sex influences disease progression, we analyzed paired samples from primary and recurrent ADG cases, aiming to identify sex-specific differences in molecular and cellular features.

RESULTS

Our analysis revealed that mutations in isocitrate dehydrogenase (IDH) genes and the tumor microenvironment emerged as primary influencers of sex-differential molecular enrichments. In IDHwt tumors, genes in the neuronal signaling pathway are found to be enriched in male tumors, while genes in hypoxia and inflammatory response pathways are enriched in female tumors. This pattern was reversed in IDHmut gliomas. We hypothesized that these distinctions could be attributed to heterogeneous cellular composition between sexes. Using single-cell data, we observed distinctive patterns of sex differences in cell states, cell composition, and cell-cell interaction in IDHwt and IDHmut tumors separately. Further, by comparing molecular changes in paired primary and recurrent ADG samples, we identified sex-specific differences in molecular characteristics and cellular compositions of recurrent tumors.

CONCLUSIONS

Our results provide a comprehensive multilevel characterization of sex differences in ADG; such findings provide novel insights into glioma disease progression in each sex.

Emerging Approaches in Glioblastoma Treatment: Modulating the Extracellular Matrix Through Nanotechnology

Glioblastoma's (GB) complex tumor microenvironment (TME) promotes its progression and resistance to therapy. A critical component of TME is the extracellular matrix (ECM), which plays a pivotal role in promoting the tumor's invasive behavior and aggressiveness. Nanotechnology holds significant promise for GB treatment, with the potential to address challenges posed by both the blood-brain barrier and the GB ECM. By enabling targeted delivery of therapeutic and diagnostic agents, nanotechnology offers the prospect of improving treatment efficacy and diagnostic accuracy at the tumor site. This review provides a comprehensive exploration of GB, including its epidemiology, classification, and current treatment strategies, alongside the intricacies of its TME. It highlights nanotechnology-based strategies, focusing on nanoparticle formulations such as liposomes, polymeric nanoparticles, and gold nanoparticles, which have shown promise in GB therapy. Furthermore, it explores how different emerging nanotechnology strategies modulate the ECM to overcome the challenges posed by its high density, which restricts drug distribution within GB tumors. By emphasizing the intersection of nanotechnology and GB ECM, this review underscores an innovative approach to advancing GB treatment. It addresses the limitations of current therapies, identifies new research avenues, and emphasizes the potential of nanotechnology to improve patient outcomes.

LDH Isoenzyme and GAA-BSA Nanoparticles: A Novel Therapy Approach for Proneural Subtype Glioblastoma Multiforme

Glioblastoma multiforme (GBM), whose pathogenesis involves proneural-to-mesenchymal transition (PMT), is the most malignant type of glioma and is associated with a bleak prognosis. Lactate dehydrogenase (LDH) comprises two major subunits, LDHA and LDHB, which can assemble into five different isoenzymes (LDH1-5). However, the role of LDH isoenzyme and its subunits in different GBM subtypes is largely unknown. Our findings reveal that LDHA and LDHB subunits correlated with mesenchymal and proneural subtype classification, and have prognostic and clinical significance in GBM patients. Moreover, it is demonstrated that LDH5, characterized by high LDHA and low LDHB levels, is highly expressed in mesenchymal subtype GBM cells and promotes proliferation, migration, and PMT. Conversely, proneural subtype GBM cells exhibited LDH1 dominance, and low LDHA and high LDHB levels. Notably, LDH1 played a pivotal role in the proliferation, migration, and PMT of proneural glioma cells. For treatment of proneural subtype GBM, gossypol-acetic acid (GAA)-bovine serum albumin (BSA) nanoparticles (GAA-BSA NPs) were developed to ameliorate PMT by targeting LDH1. These nanoparticles effectively suppress proneural subtype tumor growth both in vitro and in vivo, surpassing their efficacy against the mesenchymal subtype. The results offer several novel insights into the role of LDH isoenzyme in subtype classification between mesenchymal and proneural GBM and provide a promising therapeutic approach for proneural subtype GBM.

Understanding the Immune System and Biospecimen-Based Response in Glioblastoma: A Practical Guide to Utilizing Signal Redundancy for Biomarker and Immune Signature Discovery

Glioblastoma (GBM) is a primary central nervous system malignancy with a median survival of 15-20 months. The presence of both intra- and intertumoral heterogeneity limits understanding of biological mechanisms leading to tumor resistance, including immune escape. An attractive field of research to examine treatment resistance are immune signatures composed of cluster of differentiation (CD) markers and cytokines. CD markers are surface markers expressed on various cells throughout the body, often associated with immune cells. Cytokines are the effector molecules of the immune system. Together, CD markers and cytokines can serve as useful biomarkers to reflect immune status in patients with GBM. However, there are gaps in the understanding of the intricate interactions between GBM and the peripheral immune system and how these interactions change with standard and immune-modulating treatments. The key to understanding the true nature of these interactions is through multi-omic analysis of tumor progression and treatment response. This review aims to identify potential non-invasive blood-based biomarkers that can contribute to an immune signature through multi-omic approaches, leading to a better understanding of immune involvement in GBM.

Complement C1S is a potential prognostic biomarker and associated with M2 macrophage infiltration in gliomas: From bioinformatics to comprehensive experimental validation

Glioma is the most common malignant tumor of the central nervous system, and the ability of traditional clinical treatment to prolong the survival of glioma patients is limited. A substantial body of evidence underscores the pivotal role of the immune system in eradicating malignant cells and impeding tumor metastasis. Consequently, tumor immunotherapy has become a promising avenue to address the clinical conundrum faced by glioma patients. The complement system is a natural immune system that is an important line of defense in the immune response. C1S plays a key role in activating the classical complement system. Nevertheless, few studies have focused on the role of C1S in glioma tumorigenesis and progression. In this study, we demonstrated that C1S was upregulated in GBM (Grade IV) and low-grade gliomas (LGG, Grade II-III) by combining glioma cohorts from multiple public databases with our internal independent cohorts and that increased C1S expression levels predict a poor prognosis for gliomas. Cox regression analysis identified C1S as an important prognostic indicator for glioma patients. In addition, gene functional enrichment analysis demonstrated that C1S was involved in cellular immunity, T-cell activation, macrophage differentiation, and cell proliferation. Further experiments demonstrated that C1S facilitates tumor cell proliferation, cell migration and intracranial tumor growth in nude mice. More importantly, we evaluated the role of C1S in immune infiltration. These results suggested that C1S was closely related to a variety of immune cell types in glioma, especially M2 macrophages. Our findings were further validated via glioma tissue microarray immunohistochemical analysis and an M2 macrophage infiltration assay. Together, these findings revealed the underlying critical role of C1S in glioma tumorigenesis, progression, and the tumor immune microenvironment, contributing to further understanding of glioma pathogenesis and guiding immunotherapy.

Single-cell multi-omics analysis reveals candidate therapeutic drugs and key transcription factor specifically for the mesenchymal subtype of glioblastoma

The inherent heterogeneity of tumor cells impedes the development of targeted therapies for specific glioblastoma (GBM) subtypes. This study aims to investigate the mesenchymal subtype of GBM to uncover detailed characteristics, potential therapeutic strategies, and improve precision treatment for GBM patients. We integrated single-cell RNA sequencing (scRNA-seq), single-nucleus assay for transposase-accessible chromatin sequencing (snATAC-seq), and bulk RNA sequencing datasets to identify core gene modules, candidate therapeutic drugs, and key transcription factors specific to mesenchymal subtype GBM tumor cells which we validated in vitro and human samples. Our analysis encompassed a heterogeneous single-cell landscape of 55,845 cells from tumor and adjacent normal tissues, focusing on the mesenchymal subtype's adverse prognosis and its association with hypoxia. We identified a core gene module composed of 38 genes and, through pharmacogenomic analysis, found that Trametinib and Dasatinib exhibit increased effectiveness against mesenchymal subtype GBM cells. Furthermore, by incorporating snATAC-seq data, we delineated a crucial regulatory network and pinpointed the key transcription factor CEBPG. Our research has highlighted the strong link between the mesenchymal-like (MES-like) properties of GBM and hypoxia, providing valuable insights into candidate drugs and pivotal targets for precision treatment of the mesenchymal subtype.

Muscarinic receptor drug trihexyphenidyl can alter growth of mesenchymal glioblastoma in vivo

Glioblastoma (GBM) is the most commonly occurring and most aggressive primary brain tumor. Transcriptomics-based tumor subtype classification has established the mesenchymal lineage of GBM (MES-GBM) as cancers with particular aggressive behavior and high levels of therapy resistance. Previously it was show that Trihexyphenidyl (THP), a market approved M1 muscarinic receptor-targeting oral drug can suppress proliferation and survival of GBM stem cells from the classical transcriptomic subtype. In a series of in vitro experiments, this study confirms the therapeutic potential of THP, by effectively suppressing the growth, proliferation and survival of MES-GBM cells with limited effects on non-tumor cells. Transcriptomic profiling of treated cancer cells identified genes and associated metabolic signaling pathways as possible underlying molecular mechanisms responsible for THP-induced effects. In vivo trials of THP in immunocompromised mice carry orthotopic MES-GBMs showed moderate response to the drug. This study further highlights the potential of THP repurposing as an anti-cancer treatment regimen but mode of action and d optimal treatment procedures for in vivo regimens need to be investigated further.

Glioblastoma mesenchymal subtype enhances antioxidant defence to reduce susceptibility to ferroptosis

Glioblastoma (GBM) represents an aggressive brain tumor, characterized by intra- and inter-tumoral heterogeneity and therapy resistance, leading to unfavourable prognosis. An increasing number of studies pays attention on the regulation of ferroptosis, an iron-dependent cell death, as a strategy to reverse drug resistance in cancer. However, the debate on whether this strategy may have important implications for the treatment of GBM is still ongoing. In the present study, we used ferric ammonium citrate and erastin to evaluate ferroptosis induction effects on two human GBM cell lines, U-251 MG, with proneural characteristics, and T98-G, with a mesenchymal profile. The response to ferroptosis induction was markedly different between cell lines, indeed T98-G cells showed an enhanced antioxidant defence, with increased glutathione levels, as compared to U-251 MG cells. Moreover, using bioinformatic approaches and analysing publicly available datasets from patients' biopsies, we found that GBM with a mesenchymal phenotype showed an up-regulation of several genes involved in antioxidant mechanisms as compared to proneural subtype. Thus, our results suggest that GBM subtypes differently respond to ferroptosis induction, emphasizing the significance of further molecular studies on GBM to better discriminate between various tumor subtypes and progressively move towards personalized therapy.

B cell-based therapy produces antibodies that inhibit glioblastoma growth

Glioblastoma (GBM) is a highly aggressive and malignant brain tumor with limited therapeutic options and a poor prognosis. Despite current treatments, the invasive nature of GBM often leads to recurrence. A promising alternative strategy is to harness the potential of the immune system against tumor cells. Our previous data showed that the BVax (B cell-based vaccine) can induce therapeutic responses in preclinical models of GBM. In this study, we aimed to characterize the antigenic reactivity of BVax-derived Abs and evaluate their therapeutic potential. We performed immunoproteomics and functional assays in murine models and samples from patients with GBM. Our investigations revealed that BVax distributed throughout the GBM tumor microenvironment and then differentiated into Ab-producing plasmablasts. Proteomics analyses indicated that the Abs produced by BVax had unique reactivity, predominantly targeting factors associated with cell motility and the extracellular matrix. Crucially, these Abs inhibited critical processes such as GBM cell migration and invasion. These findings provide valuable insights into the therapeutic potential of BVax-derived Abs for patients with GBM, pointing toward a novel direction for GBM immunotherapy.

Gene regulatory network topology governs resistance and treatment escape in glioma stem-like cells

Poor prognosis and drug resistance in glioblastoma (GBM) can result from cellular heterogeneity and treatment-induced shifts in phenotypic states of tumor cells, including dedifferentiation into glioma stem-like cells (GSCs). This rare tumorigenic cell subpopulation resists temozolomide, undergoes proneural-to-mesenchymal transition (PMT) to evade therapy, and drives recurrence. Through inference of transcriptional regulatory networks (TRNs) of patient-derived GSCs (PD-GSCs) at single-cell resolution, we demonstrate how the topology of transcription factor interaction networks drives distinct trajectories of cell-state transitions in PD-GSCs resistant or susceptible to cytotoxic drug treatment. By experimentally testing predictions based on TRN simulations, we show that drug treatment drives surviving PD-GSCs along a trajectory of intermediate states, exposing vulnerability to potentiated killing by siRNA or a second drug targeting treatment-induced transcriptional programs governing nongenetic cell plasticity. Our findings demonstrate an approach to uncover TRN topology and use it to rationally predict combinatorial treatments that disrupt acquired resistance in GBM.

Comprehensive understanding of glioblastoma molecular phenotypes: classification, characteristics, and transition

Among central nervous system-associated malignancies, glioblastoma (GBM) is the most common and has the highest mortality rate. The high heterogeneity of GBM cell types and the complex tumor microenvironment frequently lead to tumor recurrence and sudden relapse in patients treated with temozolomide. In precision medicine, research on GBM treatment is increasingly focusing on molecular subtyping to precisely characterize the cellular and molecular heterogeneity, as well as the refractory nature of GBM toward therapy. Deep understanding of the different molecular expression patterns of GBM subtypes is critical. Researchers have recently proposed tetra fractional or tripartite methods for detecting GBM molecular subtypes. The various molecular subtypes of GBM show significant differences in gene expression patterns and biological behaviors. These subtypes also exhibit high plasticity in their regulatory pathways, oncogene expression, tumor microenvironment alterations, and differential responses to standard therapy. Herein, we summarize the current molecular typing scheme of GBM and the major molecular/genetic characteristics of each subtype. Furthermore, we review the mesenchymal transition mechanisms of GBM under various regulators.

CRISPR-Cas9 library screening combined with an exosome-targeted delivery system addresses tumorigenesis/TMZ resistance in the mesenchymal subtype of glioblastoma

Rationale: The large-scale genomic analysis classifies glioblastoma (GBM) into three major subtypes, including classical (CL), proneural (PN), and mesenchymal (MES) subtypes. Each of these subtypes exhibits a varying degree of sensitivity to the temozolomide (TMZ) treatment, while the prognosis corresponds to the molecular and genetic characteristics of the tumor cell type. Tumors with MES features are predominantly characterized by the NF1 deletion/alteration, leading to sustained activation of the RAS and PI3K-AKT signaling pathways in GBM and tend to acquire drug resistance, resulting in the worst prognosis compared to other subtypes (PN and CL). Here, we used the CRISPR/Cas9 library screening technique to detect TMZ-related gene targets that might play roles in acquiring drug resistance, using overexpressed KRAS-G12C mutant GBM cell lines. The study identified a key therapeutic strategy to address the chemoresistance against the MES subtype of GBM. Methods: The CRISPR-Cas9 library screening was used to discover genes associated with TMZ resistance in the U87-KRAS (U87-MG which is overexpressed KRAS-G12C mutant) cells. The patient-derived GBM primary cell line TBD0220 was used for experimental validations in vivo and in vitro. Chromatin isolation by RNA purification (ChIRP) and chromatin immunoprecipitation (ChIP) assays were used to elucidate the silencing mechanism of tumor suppressor genes in the MES-GBM subtype. The small-molecule inhibitor EPIC-0412 was obtained through high-throughput screening. Transmission electron microscopy (TEM) was used to characterize the exosomes (Exos) secreted by GBM cells after TMZ treatment. Blood-derived Exos-based targeted delivery of siRNA, TMZ, and EPIC-0412 was optimized to tailor personalized therapy in vivo. Results: Using the genome-wide CRISPR-Cas9 library screening, we found that the ERBIN gene could be epigenetically regulated in the U87-KRAS cells. ERBIN overexpression inhibited the RAS signaling and downstream proliferation and invasion effects of GBM tumor cells. EPIC-0412 treatment inhibited tumor proliferation and EMT progression by upregulating the ERBIN expression both in vitro and in vivo. Genome-wide CRISPR-Cas9 screening also identified RASGRP1(Ras guanine nucleotide-releasing protein 1) and VPS28(Vacuolar protein sorting-associated protein 28) genes as synthetically lethal in response to TMZ treatment in the U87-KRAS cells. We found that RASGRP1 activated the RAS-mediated DDR pathway by promoting the RAS-GTP transformation. VPS28 promoted the Exos secretion and decreased intracellular TMZ concentration in GBM cells. The targeted Exos delivery system encapsulating drugs and siRNAs together showed a powerful therapeutic effect against GBM in vivo. Conclusions: We demonstrate a new mechanism by which ERBIN is epigenetically silenced by the RAS signaling in the MES subtype of GBM. Restoration of the ERBIN expression with EPIC-0412 significantly inhibits the RAS signaling downstream. RASGRP1 and VPS28 genes are associated with the promotion of TMZ resistance through RAS-GDP to RAS-GTP transformation and TMZ efflux, as well. A quadruple combination therapy based on a targeted Exos delivery system demonstrated significantly reduced tumor burden in vivo. Therefore, our study provides new insights and therapeutic approaches for regulating tumor progression and TMZ resistance in the MES-GBM subtype.

TAK1 inhibition leads to RIPK1-dependent apoptosis in immune-activated cancers

Poor survival and lack of treatment response in glioblastoma (GBM) is attributed to the persistence of glioma stem cells (GSCs). To identify novel therapeutic approaches, we performed CRISPR/Cas9 knockout screens and discovered TGFβ activated kinase (TAK1) as a selective survival factor in a significant fraction of GSCs. Loss of TAK1 kinase activity results in RIPK1-dependent apoptosis via Caspase-8/FADD complex activation, dependent on autocrine TNFα ligand production and constitutive TNFR signaling. We identify a transcriptional signature associated with immune activation and the mesenchymal GBM subtype to be a characteristic of cancer cells sensitive to TAK1 perturbation and employ this signature to accurately predict sensitivity to the TAK1 kinase inhibitor HS-276. In addition, exposure to pro-inflammatory cytokines IFNγ and TNFα can sensitize resistant GSCs to TAK1 inhibition. Our findings reveal dependency on TAK1 kinase activity as a novel vulnerability in immune-activated cancers, including mesenchymal GBMs that can be exploited therapeutically.

ELAVL2 loss promotes aggressive mesenchymal transition in glioblastoma

Glioblastoma (GBM), the most lethal primary brain cancer, exhibits intratumoral heterogeneity and molecular plasticity, posing challenges for effective treatment. Despite this, the regulatory mechanisms underlying such plasticity, particularly mesenchymal (MES) transition, remain poorly understood. In this study, we elucidate the role of the RNA-binding protein ELAVL2 in regulating aggressive MES transformation in GBM. We found that ELAVL2 is most frequently deleted in GBM compared to other cancers and associated with distinct clinical and molecular features. Transcriptomic analysis revealed that ELAVL2-mediated alterations correspond to specific GBM subtype signatures. Notably, ELAVL2 expression negatively correlated with epithelial-to-mesenchymal transition (EMT)-related genes, and its loss promoted MES process and chemo-resistance in GBM cells, whereas ELAVL2 overexpression exerted the opposite effect. Further investigation via tissue microarray analysis demonstrated that high ELAVL2 protein expression confers a favorable survival outcome in GBM patients. Mechanistically, ELAVL2 was shown to directly bind to the transcripts of EMT-inhibitory molecules, SH3GL3 and DNM3, modulating their mRNA stability, potentially through an m6A-dependent mechanism. In summary, our findings identify ELAVL2 as a critical tumor suppressor and mRNA stabilizer that regulates MES transition in GBM, underscoring its role in transcriptomic plasticity and glioma progression.

Modeling the precise interaction of glioblastoma with human brain region-specific organoids

Glioblastoma is a highly aggressive malignant tumor of the central nervous system, but the interaction between glioblastoma and different types of neurons remains unclear. Here, we established a co-culture model in vitro using 3D printed molds with microchannels, in which glioblastoma organoids (GB), dorsal forebrain organoids (DO, mainly composed of excitatory neurons), and ventral forebrain organoids (VO, mainly composed of inhibitory neurons) were assembled. Our results indicate that DO has a greater impact on altered gene expression profiles of GB, resulting in increased invasive potential. GB cells preferentially invaded DO along axons, whereas this phenomenon was not observed in VO. Furthermore, GB cells selectively inhibited neurite outgrowth in DOs and reduced the expression of the vesicular GABA transporter (VGAT), leading to neuronal hyperexcitability. By revealing how glioblastoma interacts with brain cells, our study provides a more comprehensive understanding of this disease.

Identification of TMZ resistance-associated histone post-translational modifications in glioblastoma using multi-omics data

BACKGROUD

Glioblastoma multiforme (GBM) is among the most aggressive cancers, with current treatments limited in efficacy. A significant hurdle in the treatment of GBM is the resistance to the chemotherapeutic agent temozolomide (TMZ). The methylation status of the MGMT promoter has been implicated as a critical biomarker of response to TMZ.

METHODS

To explore the mechanisms underlying resistance, we developed two TMZ-resistant GBM cell lines through a gradual increase in TMZ exposure. Transcriptome sequencing of TMZ-resistant cell lines revealed that alterations in histone post-translational modifications might be instrumental in conferring TMZ resistance. Subsequently, multi-omics analysis suggests a strong association between histone H3 lysine 9 acetylation (H3K9ac) levels and TMZ resistance.

RESULTS

We observed a significant correlation between the expression of H3K9ac and MGMT, particularly in the unmethylated MGMT promoter samples. More importantly, our findings suggest that H3K9ac may enhance MGMT transcription by facilitating the recruitment of the SP1 transcription factor to the MGMT transcription factor binding site. Additionally, by analyzing single-cell transcriptomics data from matched primary and recurrent GBM tumors treated with TMZ, we modeled the molecular shifts occurring upon tumor recurrence. We also noted a reduction in tumor stem cell characteristics, accompanied by an increase in H3K9ac, SP1, and MGMT levels, underscoring the potential role of H3K9ac in tumor relapse following TMZ therapy.

CONCLUSIONS

The increase in H3K9ac appears to enhance the recruitment of the transcription factor SP1 to its binding sites within the MGMT locus, consequently upregulating MGMT expression and driving TMZ resistance in GBM.

Gene regulatory network topology governs resistance and treatment escape in glioma stem-like cells

Poor prognosis and drug resistance in glioblastoma (GBM) can result from cellular heterogeneity and treatment-induced shifts in phenotypic states of tumor cells, including dedifferentiation into glioma stem-like cells (GSCs). This rare tumorigenic cell subpopulation resists temozolomide, undergoes proneural-to-mesenchymal transition (PMT) to evade therapy, and drives recurrence. Through inference of transcriptional regulatory networks (TRNs) of patient-derived GSCs (PD-GSCs) at single-cell resolution, we demonstrate how the topology of transcription factor interaction networks drives distinct trajectories of cell state transitions in PD-GSCs resistant or susceptible to cytotoxic drug treatment. By experimentally testing predictions based on TRN simulations, we show that drug treatment drives surviving PD-GSCs along a trajectory of intermediate states, exposing vulnerability to potentiated killing by siRNA or a second drug targeting treatment-induced transcriptional programs governing non-genetic cell plasticity. Our findings demonstrate an approach to uncover TRN topology and use it to rationally predict combinatorial treatments that disrupts acquired resistance in GBM.

FBXO7 Confers Mesenchymal Properties and Chemoresistance in Glioblastoma by Controlling Rbfox2-Mediated Alternative Splicing

Mesenchymal glioblastoma (GBM) is highly resistant to radio-and chemotherapy and correlates with worse survival outcomes in GBM patients; however, the underlying mechanism determining the mesenchymal phenotype remains largely unclear. Herein, it is revealed that FBXO7, a substrate-recognition component of the SCF complex implicated in the pathogenesis of Parkinson's disease, confers mesenchymal properties and chemoresistance in GBM by controlling Rbfox2-mediated alternative splicing. Specifically, FBXO7 ubiquitinates Rbfox2 Lys249 through K63-linked ubiquitin chains upon arginine dimethylation at Arg341 and Arg441 by PRMT5, leading to Rbfox2 stabilization. FBXO7 controls Rbfox2-mediated splicing of mesenchymal genes, including FoxM1, Mta1, and Postn. FBXO7-induced exon Va inclusion of FoxM1 promotes FoxM1 phosphorylation by MEK1 and nuclear translocation, thereby upregulates CD44, CD9, and ID1 levels, resulting in GBM stem cell self-renewal and mesenchymal transformation. Moreover, FBXO7 is stabilized by temozolomide, and FBXO7 depletion sensitizes tumor xenografts in mice to chemotherapy. The findings demonstrate that the FBXO7-Rbfox2 axis-mediated splicing contributes to mesenchymal transformation and tumorigenesis, and targeting FBXO7 represents a potential strategy for GBM treatment.

Dysregulation of inflammasome activation in glioma

Gliomas are the most common brain tumors characterized by complicated heterogeneity. The genetic, molecular, and histological pathology of gliomas is characterized by high neuro-inflammation. The inflammatory microenvironment in the central nervous system (CNS) has been closely linked with inflammasomes that control the inflammatory response and coordinate innate host defenses. Dysregulation of the inflammasome causes an abnormal inflammatory response, leading to carcinogenesis in glioma. Because of the clinical importance of the various physiological properties of the inflammasome in glioma, the inflammasome has been suggested as a promising treatment target for glioma management. Here, we summarize the current knowledge on the contribution of the inflammasomes in glioma and therapeutic insights. Video Abstract.

Enhancing Transcriptional Reprogramming of Mesenchymal Glioblastoma with Grainyhead-like 2 and HDAC Inhibitors Leads to Apoptosis and Cell-Cycle Dysregulation

Glioblastoma (GBM) tumor cells exhibit mesenchymal properties which are thought to play significant roles in therapeutic resistance and tumor recurrence. An important question is whether impairment of the mesenchymal state of GBM can sensitize these tumors to therapeutic intervention. HDAC inhibitors (HDACi) are being tested in GBM for their ability promote mesenchymal-to-epithelial transcriptional (MET) reprogramming, and for their cancer-specific ability to dysregulate the cell cycle and induce apoptosis. We set out to enhance the transcriptional reprogramming and apoptotic effects of HDACi in GBM by introducing an epithelial transcription factor, Grainyhead-like 2 (GRHL2), to specifically counter the mesenchymal state. GRHL2 significantly enhanced HDACi-mediated MET reprogramming. Surprisingly, we found that inducing GRHL2 in glioma stem cells (GSCs) altered cell-cycle drivers and promoted aneuploidy. Mass spectrometry analysis of GRHL2 interacting proteins revealed association with several key mitotic factors, suggesting their exogenous expression disrupted the established mitotic program in GBM. Associated with this cell-cycle dysregulation, the combination of GRHL2 and HDACi induced elevated levels of apoptosis. The key implication of our study is that although genetic strategies to repress the mesenchymal properties of glioblastoma may be effective, biological interactions of epithelial factors in mesenchymal cancer cells may dysregulate normal homeostatic cellular mechanisms.

Glioblastoma Mesenchymal Transition and Invasion are Dependent on a NF-κB/BRD2 Chromatin Complex

Glioblastoma (GBM) represents the most aggressive subtype of glioma, noted for its profound invasiveness and molecular heterogeneity. The mesenchymal (MES) transcriptomic subtype is frequently associated with therapy resistance, rapid recurrence, and increased tumor-associated macrophages. Notably, activation of the NF-κB pathway and alterations in the PTEN gene are both associated with this malignant transition. Although PTEN aberrations have been shown to be associated with enhanced NF-κB signaling, the relationships between PTEN, NF-κB and MES transition are poorly understood in GBM. Here, we show that PTEN regulates the chromatin binding of bromodomain and extraterminal (BET) family proteins, BRD2 and BRD4, mediated by p65/RelA localization to the chromatin. By utilizing patient-derived glioblastoma stem cells and CRISPR gene editing of the RELA gene, we demonstrate a crucial role for RelA lysine 310 acetylation in recruiting BET proteins to chromatin for MES gene expression and GBM cell invasion upon PTEN loss. Remarkably, we found that BRD2 is dependent on chromatin associated acetylated RelA for its recruitment to MES gene promoters and their expression. Furthermore, loss of BRD2 results in the loss of MES signature, accompanied by an enrichment of proneural signature and enhanced therapy responsiveness. Finally, we demonstrate that disrupting the NFκB/BRD2 interaction with a brain penetrant BET-BD2 inhibitor reduces mesenchymal gene expression, GBM invasion, and therapy resistance in GBM models. This study uncovers the role of hitherto unexplored PTEN-NF-κB-BRD2 pathway in promoting MES transition and suggests inhibiting this complex with BET-BD2 specific inhibitors as a therapeutic approach to target the MES phenotype in GBM.

Identification of thioredoxin domain containing family members' expression pattern and prognostic value in diffuse gliomas via in silico analysis

BACKGROUND

Gliomas are the most prevalent primary tumors of the central nervous system. Their aggressive nature and the obstacles arising during therapy highlights the importance of finding new prognostic markers and therapy targets for gliomas. TXNDC genes are members of the thioredoxin superfamily and were shown to play a role in redox homeostasis, protein folding, electron transfer and also acting as cellular adapters. The well known contribution of these processes in cancer progression prompted us to investigate if TXNDC family members may also play a role in carcinogenesis, in particular diffuse gliomas.

METHODS

The present study used in silico analysis tools GEPIA, UCSC Xena, Gliovis, cBioPortal, and Ivy GAP to evaluate the expression pattern, prognostic value and clinical significance of TXNDC family members in diffuse gliomas.

RESULTS

Our analysis showed that TXNDC family members' expression pattern differ between tumors and healthy tissues and among tumors with different grades. The detailed analysis of TXNDC5 in glioma pathogenesis revealed that TXNDC5 expression is associated with more aggressive clinical and molecular features and poor therapy success both in LGG and GBM samples. Kaplan-Meier survival curves represented a worse prognosis for patients with leveated TXNDC5 levels in LGG and all grade glioma patients. The levels of TXNDC5 was shown to be possibly regulated by hypoxia-ER stress axis and a potential mechanism for TXNDC5-driven glioma progression was found to be extracellular matrix (ECM) production which is known to promote tumor aggressiveness.

CONCLUSIONS

Our results uncovered the previously unknown role of TXNDC family members in glioma pathogenesis and showed that TXNDC5 levels could serve as a predictor of clinical outcome and therapy success and may very well be used for targeted therapy.

Glioblastoma immuno-endothelial multicellular microtissue as a 3D in vitro evaluation tool of anti-cancer nano-therapeutics

Despite being the most prevalent and lethal type of adult brain cancer, glioblastoma (GBM) remains intractable. Promising anti-GBM nanoparticle (NP) systems have been developed to improve the anti-cancer performance of difficult-to-deliver therapeutics, with particular emphasis on tumor targeting strategies. However, current disease modeling toolboxes lack close-to-native in vitro models that emulate GBM microenvironment and bioarchitecture, thus partially hindering translation due to poorly predicted clinical responses. Herein, human GBM heterotypic multicellular tumor microtissues (MCTMs) are generated through high-throughput 3D modeling of U-251 MG tumor cells, tissue differentiated macrophages isolated from peripheral monocytes, and brain microvascular primary endothelial cells. GBM MCTMs mimicked tumor spatial organization, extracellular matrix production and necrosis areas. The bioactivity of a model drug, docetaxel (DTX), and of tumor-targeted DTX-loaded polymeric NPs with a surface L-Histidine moiety (H-NPs), were assessed in the MCTMs. MCTMs cell uptake and anti-proliferative effect was 8- and 3-times higher for H-NPs, respectively, compared to the non-targeted NPs and to free DTX. H-NPs provided a decrease of MCTMs anti-inflammatory M2-macrophages, while increasing their pro-inflammatory M1 counterparts. Moreover, H-NPs showed a particular biomolecular signature through reduced secretion of an array of medium cytokines (IFN-γ, IL-1β, IL-1Ra, IL-6, IL-8, TGF-β). Overall, MCTMs provide an in vitro biomimetic model to recapitulate key cellular and structural features of GBM and improve in vivo drug response predictability, fostering future clinical translation of anti-GBM nano-therapeutic strategies.

Targeting interleukin-13 receptor α2 (IL-13Rα2) for glioblastoma therapy with surface functionalized nanocarriers

Despite surgical and therapeutic advances, glioblastoma multiforme (GBM) is among the most fatal primary brain tumor that is aggressive in nature. Patients with GBM have a median lifespan of just 15 months when treated with the current standard of therapy, which includes surgical resection and concomitant chemo-radiotherapy. In recent years, nanotechnology has shown considerable promise in treating a variety of illnesses, and certain nanomaterials have been proven to pass the blood-brain barrier (BBB) and stay in glioblastoma tissues. Recent preclinical research suggests that the diagnosis and treatment of brain tumor is significantly explored through the intervention of nanomaterials that has showed enhanced effect. In order to elicit an antitumor response, it is necessary to retain the therapeutic candidates within glioblastoma tissues and this job is effectively carried out by nanocarrier particularly functionalized nanocarriers. In the arena of neoplastic diseases including GBM have achieved great attention in recent decades. Furthermore, interleukin-13 receptor α chain variant 2 (IL13Rα2) is a highly expressed and studied target in GBM that is lacked by the surrounding environment. The absence of IL13Rα2 in surrounding normal tissues has made it a suitable target in glioblastoma therapy. In this review article, we highlighted the role of IL13Rα2 as a potential target in GBM along with design and fabrication of efficient targeting strategies for IL13Rα2 through surface functionalized nanocarriers.

Oncogenic potential of PIK3CD in glioblastoma is exerted through cytoskeletal proteins PAK3 and PLEK2

The Class I_A phosphoinositide-3-kinase catalytic isoforms p110α, p110β, and p110δ have been implicated to play vital but overlapping roles in various cancers, including glioblastoma (GBM). We have previously shown that PIK3CD, encoding p110δ, is highly expressed in multiple glioma cell lines and involved in glioma cell migration and invasion. Based on the RNA sequencing data from The Cancer Genome Atlas (TCGA) database, we found the level of PIK3CD expression is significantly higher in GBM than WHO grade II and III gliomas and is closely related to poor survival. To further dissect the oncogenic roles of PIK3CD in glioma progression, we employed CRISPR/Cas9 to completely abrogate its expression in the GBM cell line U87-MG and have successfully isolated two knockout clones with different gene modifications. As expected, the knockout clones exhibited significantly lower migration and invasion capabilities when compared with their parental cells. Interestingly, knockout of PIK3CD also dramatically reduced the colony formation ability of the knockout cells. Further study revealed that PIK3CD deficiency could negate tumorigenesis in nude mice. To determine the downstream effect of PIK3CD depletion, we performed RT² profiler PCR array of selected gene sets and found that knockout of PIK3CD impaired the activity of p-21 activated kinase 3 (PAK3) and pleckstrin 2 (PLEK2), molecules involved in cancer cell migration and proliferation. This explains why the glioma cells without the PIK3CD expression exhibited weaker oncogenic features. Further, RNAseq analysis of parent and knockout clones revealed that this interaction might happen through axonogenesis signaling pathway. Taken together, we demonstrated that PIK3CD could be a potential prognostic factor and therapeutic target for GBM patients.

Efficacy and Mechanism of Roxadustat plus Oral Iron in the Treatment of Elderly Chronic Kidney Disease with Anemia

Objective

For investigating the efficacy and mechanism of Roxadustat + oral iron in the treatment of elderly chronic kidney disease (CKD) complicated with anemia.

Methods

A total of 100 elderly patients with CKD and anemia admitted to our hospital between April 2020 and December 2021 were enrolled as research subjects, and the patients were assigned to control group (Con group, n = 50) or experimental group (Exp group, n = 50). The patients in the Con group were given oral iron, and those in the Exp group were given Roxadustat capsule based on the Con group. Both groups were given subcutaneous injection of recombinant human erythropoietin. The clinical efficacy, anemia indexes, iron metabolism indexes, inflammatory indexes, and adverse reactions were compared between the two groups.

Results

The Exp group showed a notably higher treatment effective rate than the Con group (P < 0.05). After treatment, the anemia indexes, iron metabolism indexes, and inflammatory indexes in the Exp group were notably better than those in the Con group (P < 0.05). The Exp group showed a notably lower incidence of adverse reactions during treatment than the Con group (P < 0.05).

Conclusion

Roxadustat plus oral iron yields a pronounced clinical efficacy in the therapy of elderly patients with CKD and anemia.

Spatiotemporal analysis of glioma heterogeneity reveals COL1A1 as an actionable target to disrupt tumor progression

Intra-tumoral heterogeneity is a hallmark of glioblastoma that challenges treatment efficacy. However, the mechanisms that set up tumor heterogeneity and tumor cell migration remain poorly understood. Herein, we present a comprehensive spatiotemporal study that aligns distinctive intra-tumoral histopathological structures, oncostreams, with dynamic properties and a specific, actionable, spatial transcriptomic signature. Oncostreams are dynamic multicellular fascicles of spindle-like and aligned cells with mesenchymal properties, detected using ex vivo explants and in vivo intravital imaging. Their density correlates with tumor aggressiveness in genetically engineered mouse glioma models, and high grade human gliomas. Oncostreams facilitate the intra-tumoral distribution of tumoral and non-tumoral cells, and potentially the collective invasion of the normal brain. These fascicles are defined by a specific molecular signature that regulates their organization and function. Oncostreams structure and function depend on overexpression of COL1A1. Col1a1 is a central gene in the dynamic organization of glioma mesenchymal transformation, and a powerful regulator of glioma malignant behavior. Inhibition of Col1a1 eliminates oncostreams, reprograms the malignant histopathological phenotype, reduces expression of the mesenchymal associated genes, induces changes in the tumor microenvironment and prolongs animal survival. Oncostreams represent a pathological marker of potential value for diagnosis, prognosis, and treatment.

NOX2-Induced High Glycolytic Activity Contributes to the Gain of COL5A1-Mediated Mesenchymal Phenotype in GBM

Simple Summary

Glioblastoma multiforme (GBM) is the most aggressive type of glioma and exhibits extensive heterogeneity and poor prognosis with a high recurrence rate. Among the genetic alterations in GBM with different phenotypic states, a mesenchymal subtype has been associated with a worse outcome in patients with GBM. The mechanisms for the gain of the mesenchymal subtype in GBM remain unclear. Our aim was to investigate whether NOX2-induced high glycolytic activity could contribute to the gain of the mesenchymal phenotype in GBM. We revealed that NOX2-induced high glycolytic activity can induce the gain of the COL5A1-mediated mesenchymal phenotype in GBM. Our findings will provide the molecular mechanism by which NOX2 contributes to the gain of mesenchymal phenotype in GBM.

Abstract

The alteration of the cellular metabolism is a hallmark of glioma. The high glycolytic phenotype is a critical factor in the pathogenesis of high-grade glioma, including glioblastoma multiforme (GBM). GBM has been stratified into three subtypes as the proneural, mesenchymal, and classical subtypes. High glycolytic activity was found in mesenchymal GBM relative to proneural GBM. NADPH oxidase 2 (NOX2) has been linked to cellular metabolism and epithelial-mesenchymal transition (EMT) in tumors. The role of NOX2 in the regulation of the high glycolytic phenotype and the gain of the mesenchymal subtype in glioma remain unclear. Here, our results show that the levels of NOX2 were elevated in patients with GBM. NOX2 induces hexokinase 2 (HK2)-dependent high glycolytic activity in U87MG glioma cells. High levels of NOX2 are correlated with high levels of HK2 and glucose uptake in patients with GBM relative to benign glioma. Moreover, NOX2 increases the expression of mesenchymal-subtype-related genes, including COL5A1 and FN1 in U87MG glioma cells. High levels of NOX2 are correlated with high levels of COL5A1 and the accumulation of extracellular matrix (ECM) in patients with GBM relative to benign glioma. Furthermore, high levels of HK2 are correlated with high levels of COL5A1 in patients with GBM relative to benign glioma. Our results suggest that NOX2-induced high glycolytic activity contributes to the gain of the COL5A1-mediated mesenchymal phenotype in GBM.

Comprehensive omics analyses profile genesets related with tumor heterogeneity of multifocal glioblastomas and reveal LIF/CCL2 as biomarkers for mesenchymal subtype

Rationale: Around 10%-20% patients with glioblastoma (GBM) are diagnosed with more than one tumor lesions or multifocal GBM (mGBM). However, the understanding on genetic, DNA methylomic, and transcriptomic characteristics of mGBM is still limited.

Methods: In this study, we collected nine tumor foci from three mGBM patients followed by whole genome sequencing, whole genome bisulfite sequencing, RNA sequencing, and immunohistochemistry. The data were further examined using public GBM databases and GBM cell line.

Results: Analysis on genetic data confirmed common features of GBM, including gain of chr.7 and loss of chr.10, loss of critical tumor suppressors, high frequency of PDGFA and EGFR amplification. Through profiling DNA methylome of individual tumor foci, we found that promoter methylation status of genes involved in detection of chemical stimulus, immune response, and Hippo/YAP1 pathway was significantly changed in mGBM. Although both CNV and promoter methylation alteration were involved in heterogeneity of different tumor foci from same patients, more CNV events than promoter hypomethylation events were shared by different tumor foci, implying CNV were relatively earlier than promoter methylation alteration during evolution of different tumor foci from same mGBM. Moreover, different tumor foci from same mGBM assumed different molecular subtypes and mesenchymal subtype was prevalent in mGBM, which might explain the worse prognosis of mGBM than single GBM. Interestingly, we noticed that LIF and CCL2 was tightly correlated with mesenchymal subtype tumor focus in mGBM and predicted poor survival of GBM patients. Treatment with LIF and CCL2 produced mesenchymal-like transcriptome in GBM cells.

Conclusions: Together, our work herein comprehensively profiled multi-omics features of mGBM and emphasized that components of extracellular microenvironment, such as LIF and CCL2, contributed to the evolution and prognosis of tumor foci in mGBM patients.

Olfactory receptor 5B21 drives breast cancer metastasis

Olfactory receptors (ORs), responsible for the sense of smell, play an essential role in various physiological processes outside the nasal epithelium, including cancer. In breast cancer, however, the expression and function of ORs remain understudied. We examined the significance of OR transcript abundance in primary and metastatic breast cancer to the brain, bone, and lung. Although 20 OR transcripts were differentially expressed in distant metastases, OR5B21 displayed an increased transcript abundance in all three metastatic sites compared with the primary tumor. Knockdown of OR5B21 significantly decreased the invasion and migration of breast cancer cells as well as metastasis to different organs especially the brain, whereas increasing of OR5B21 transcript abundance had the opposite effect. Mechanistically, OR5B21 expression was associated with epithelial to mesenchymal transition through the STAT3/NF-κB/CEBPβ signaling axis. We propose OR5B21 (and potentially other ORs) as a novel oncogene contributing to breast cancer metastasis and a potential target for adjuvant therapy.

Versatile metal-phenolic network nanoparticles for multitargeted combination therapy and magnetic resonance tracing in glioblastoma

Glioblastoma multiforme (GBM) is a common malignancy of the central nervous system, but conventional treatments yield unsatisfactory results. Although innovative therapeutic approaches have been developed, they prolong survival by only approximately 5 months. The heterogeneity of GBM renders growth inhibition with a single drug difficult, and exploring combination approaches with multiple targets for the comprehensive treatment of GBM is expected to overcome this limitation. In this study, we designed a biocompatible cRGD/Pt + DOX@GFNPs (RPDGs) nanoformulation to disrupt redox homeostasis in GBM cells and promote the simultaneous occurrence of efficient apoptosis and ferroptosis. Taking advantage of the highly stable Fenton reaction catalytic activity of gallic acid (GA)/Fe²⁺ nanoparticles in physiological environments, the ability of Pt (IV) to deplete glutathione (GSH) and increase reactive oxygen species (ROS) levels, and the efficient photothermal conversion efficiency of GA/Fe²⁺ nanoparticles, our synthesized multifunctional and multitargeted RPDGs significantly increased intracellular ROS levels and thus induced ferroptosis. Furthermore, the RPDGs displayed superior photothermal responsiveness and magnetic resonance imaging (MRI) capabilities. These results indicate that RPDGs can not only directly inhibit the growth of tumors but also effectively improve the efficient translocation of conventional chemotherapeutic drugs across the blood-brain barrier, thereby providing a new approach for the comprehensive treatment of GBM.

Identification of an IFN-β-associated gene signature for the prediction of overall survival among glioblastoma patients

Background

Brain glioblastoma multiforme (GBM) is the most common primary malignant intracranial tumor. The prognosis of this disease is extremely poor. While the introduction of β-interferon (IFN-β) regimen in the treatment of gliomas has significantly improved the outcome of patients; The mechanism by which IFN-β induces increased TMZ sensitivity has not been described. Therefore, the main objective of the study was to elucidate the molecular mechanisms responsible for the beneficial effect of IFNβ in GBM.

Methods

Messenger RNA expression profiles and clinicopathological data were downloaded from The Cancer Genome Atlas (TCGA) GBM and GSE83300 dataset from the Gene Expression Omnibus. Univariate Cox regression analysis and lasso Cox regression model established a novel 4-gene IFN-β signature (peroxiredoxin 1, Sec61 subunit beta, X-ray repair cross-complementing 5, and Bcl-2-like protein 2) for GBM prognosis prediction. Further, GBM samples (n=50) and normal brain tissues (n=50) were then used for real-time polymerase chain reaction experiments. Gene set enrichment analysis (GSEA) was performed to further understand the underlying molecular mechanisms. Pearson correlation was applied to calculate the correlation between the long non-coding RNAs (lncRNAs) and IFN-β-associated genes. An lncRNA with a correlation coefficient |R²|>0.3 and P<0.05 was considered to be an IFN-β-associated lncRNA.

Results

Patients in the high-risk group had significantly poorer survival than patients in the low-risk group. The signature was found to be an independent prognostic factor for GBM survival. Furthermore, GSEA revealed several significantly enriched pathways, which might help explain the underlying mechanisms. Our study identified a novel robust 4-gene IFN-β signature for GBM prognosis prediction. The signature might contain potential biomarkers for metabolic therapy and treatment response prediction for GBM patients.

Conclusions

In the present study, we established a novel IFN-β-associated gene signature to predict the overall survival of GBM patients, which may help in clinical decision making for individual treatment.

Perspective of mesenchymal transformation in glioblastoma

Despite aggressive multimodal treatment, glioblastoma (GBM), a grade IV primary brain tumor, still portends a poor prognosis with a median overall survival of 12–16 months. The complexity of GBM treatment mainly lies in the inter- and intra-tumoral heterogeneity, which largely contributes to the treatment-refractory and recurrent nature of GBM. By paving the road towards the development of personalized medicine for GBM patients, the cancer genome atlas classification scheme of GBM into distinct transcriptional subtypes has been considered an invaluable approach to overcoming this heterogeneity. Among the identified transcriptional subtypes, the mesenchymal subtype has been found associated with more aggressive, invasive, angiogenic, hypoxic, necrotic, inflammatory, and multitherapy-resistant features than other transcriptional subtypes. Accordingly, mesenchymal GBM patients were found to exhibit worse prognosis than other subtypes when patients with high transcriptional heterogeneity were excluded. Furthermore, identification of the master mesenchymal regulators and their downstream signaling pathways has not only increased our understanding of the complex regulatory transcriptional networks of mesenchymal GBM, but also has generated a list of potent inhibitors for clinical trials. Importantly, the mesenchymal transition of GBM has been found to be tightly associated with treatment-induced phenotypic changes in recurrence. Together, these findings indicate that elucidating the governing and plastic transcriptomic natures of mesenchymal GBM is critical in order to develop novel and selective therapeutic strategies that can improve both patient care and clinical outcomes. Thus, the focus of our review will be on the recent advances in the understanding of the transcriptome of mesenchymal GBM and discuss microenvironmental, metabolic, and treatment-related factors as critical components through which the mesenchymal signature may be acquired. We also take into consideration the transcriptomic plasticity of GBM to discuss the future perspectives in employing selective therapeutic strategies against mesenchymal GBM.

AS602801 sensitizes glioma cells to temozolomide and vincristine by blocking gap junction communication between glioma cells and astrocytes

Previous studies showed that the chemotherapeutic effect of temozolomide (TMZ) and vincristine (VCR) against glioma might be blunted by the co‐culture with astrocytes, and connexin‐43 (CX43) was thought to play a vital role in the communication between glioma cells and astrocytes. In this study, we aimed to investigate the combined chemotherapeutic effect of AS602801 and TMZ/ VCR in glioma cells both. Dye transfer assay was used to evaluate the gap junction activity between U251 cells and astrocytes. Western blot and immunohistochemistry were carried out to analyse the expression of p‐JNK, CX43 and CASP‐3 proteins treated under different conditions. AS602801 significantly suppressed the gap junction activity between U251 cells and astrocytes. The expression of p‐JNK and CX43 was remarkably inhibited by AS602801. TMZ/VCR‐induced apoptosis of glioma cells was effectively enhanced by AS602801 treatment. Accordingly, the inhibitory role of TMZ/VCR in the expression of p‐JNK, CX43 and CASP‐3 in glioma cells was notably restored by AS602801. Furthermore, in a glioma cell xenograft, AS602801 showed an apparent capability to enhance TMZ/VCR‐induced tumour cell apoptosis through altering the expression of p‐JNK, CX43 and CASP‐3. The findings of this study demonstrated that the co‐culture of glioma cells with astrocytes blunted the tumour killing effect of TMZ and VCR. AS602801 down‐regulated CX43 expression by inhibiting JNK. And AS602801 also sensitized glioma cells to TMZ/VCR by blocking the gap junction communication between glioma cells and astrocytes via down‐regulating CX43, indicating its potential role as a novel adjuvant chemotherapeutic agent in the treatment of glioma.