Tumor Cell Invasion in Glioblastoma

The self-organized structure of glioma oncostreams and the disruptive role of passive cells

Oncostreams are self-organized structures formed by spindle-like, elongated, self-propelled cells recently described in glioblastomas and especially in gliosarcomas. Cells within these structures either move as large clusters in one main direction, flocks, or as linear, intermingling collections of cells advancing in opposite directions, streams. Round, passive cells are also observed, either inside or segregated from the oncostreams. Here we generalize a recently formulated particle-field approach to investigate the genesis and evolution of these structures, first showing that, in systems consisting only of identical self-propelled cells, both flocks and streams emerge as self-organized dynamic configurations. Flocks are the more stable configurations, while streams are transient and usually originate in collisions between flocks. Stream degradation is easier at low self-propulsion speeds. In systems consisting of both motile and passive cells, the latter block stream formation and accelerate their degradation and flock stabilization. Since the flock appears to be the most effective invasive structure, we thus argue that a phenotype mixture (motile and passive cells) may favor glioblastoma invasion. hlBy relating cellular properties to the observed outcome, our model shows that oncostreams are self-organized structures that result from the interplay between speed, shape, and steric repulsion.

Exploring the Mechanism of Sempervirine Inhibiting Glioblastoma Invasion Based on Network Pharmacology and Bioinformatics

Background: Invasion is an important characteristic of the malignancy of glioblastoma (GBM) and a significant prognostic factor. Sempervirine (SPV), a yohimbine-type alkaloid, has been proven to inhibit GBM cells proliferation in previous research and found to have a potential effect in anti-invasion, but its mechanism of anti-invasion is still unknown. Methods: To explore its pharmacodynamics in inhibiting GBM cell invasion in this study, we combined network pharmacology and bioinformatics to comprehensive exploratory analysis of SPV and verified the mechanism in vitro. Results: Firstly, targets of SPV and invasion-related genes were collected from public databases. Moreover, GBM samples were obtained to analyze differentially expressed genes (DEGs) from The Cancer Genome Atlas (TCGA). Then, the relevant targets of SPV inhibiting GBM invasion (SIGI) were obtained through the intersection of the three gene sets. Further, GO and KEGG analysis showed that the targets of SIGI were heavily enriched in the AKT signaling pathway. Subsequently, based on the method of machine learning, a clinical prognostic model of the relevant targets of SIGI was constructed using GBM samples from TCGA and the Gene Expression Omnibus (GEO). A four-genes model (DUSP6, BMP2, MMP2, and MMP13) was successfully constructed, and Vina Scores of MMP2 and MMP13 in molecular docking were higher, which may be the main targets of SIGI. Then, the effect of SIGI was confirmed via functional experiments on invasion, migration, and adhesion assay, and the effect involved changes in the expressions of p-AKT, MMP2 and MMP13. Finally, combined with AKT activator (SC79) and inhibitor (MK2206), we further confirmed that SPV inhibits GBM invasion through AKT phosphorylation. Conclusions: This study provides valuable and an expected point of view into the regulation of AKT phosphorylation and inhibition of GBM invasion by SPV.

Characterisation of the tumour microenvironment in primary and recurrent glioblastomas

AIMS

Glioblastoma patients have a dismal prognosis, due to inevitable tumour recurrence and respond poorly to immunotherapy. Tumour-associated microglia/macrophages (TAMs) dominate the glioblastoma tumour microenvironment and have been implicated in tumour progression and immune evasion. Early recurrent glioblastomas contain focal reactive regions with occasional fibrosis, chronic inflammation, TAMs and tumour cells. Surgical specimens from these tumours are rare and provide crucial insights into glioblastoma recurrence biology. This study aimed to characterise TAM- and lymphocyte phenotypes in primary vs early- and late-recurrent glioblastomas.

METHODS

Patient-matched primary and recurrent glioblastomas were compared between patients with early recurrences (n = 11, recurrence ≤6 months) and late recurrences (n = 12, recurrence after 12-19 months). Double-immunofluorescence stains combining Iba1 with HLA-DR, CD14, CD68, CD74, CD86, CD163, CD204 and CD206 along with stains for CD20, CD3, CD8 and FOXP3 were quantified with software-based classifiers.

RESULTS

Reactive regions in early recurrent tumours contained more TAMs (31.4% vs 21.7%, P = 0.01), which showed increased expression of CD86 (59.4% vs 38.4%, P = 0.04), CD204 (48.5% vs 28.4%, P = 0.03), CD206 (25.5% vs 14.4%, P = 0.04) and increased staining intensity for CD163 (86.4 vs 57.7 arbitrary units, P = 0.02), compared to late recurring tumours. Reactive regions contained more B-lymphocytes compared to patient-matched primary tumours (0.71% vs 0.40%, P = 0.04). Fractions of total, cytotoxic and regulatory T-lymphocytes did not differ.

CONCLUSIONS

Early recurrent glioblastomas showed enrichment for TAMs, expressing both pro- and anti-inflammatory markers and B-lymphocytes. This may indicate a time-dependent response to immunotherapy explained by time-dependent alterations in the immune-microenvironment in recurrent glioblastomas.

Acquired Temozolomide Resistance Instructs Patterns of Glioblastoma Behavior in Gelatin Hydrogels

Acquired drug resistance in glioblastoma (GBM) presents a major clinical challenge and is a key factor contributing to abysmal prognosis, with less than 15 months median overall survival. Aggressive chemotherapy with the frontline therapeutic, temozolomide (TMZ), ultimately fails to kill residual highly invasive tumor cells after surgical resection and radiotherapy. Here, a 3D engineered model of acquired TMZ resistance is reported using two isogenically matched sets of GBM cell lines encapsulated in gelatin methacrylol hydrogels. Response of TMZ-resistant versus TMZ-sensitive GBM cell lines within the gelatin-based extracellular matrix platform is benchmarked and drug response at physiologically relevant TMZ concentrations is further validated. The changes in drug sensitivity, cell invasion, and matrix-remodeling cytokine production are shown as the result of acquired TMZ resistance. This platform lays the foundation for future investigations targeting key elements of the GBM tumor microenvironment to combat GBM's devastating impact by advancing the understanding of GBM progression and treatment response to guide the development of novel treatment strategies.

An ILK/STAT3 pathway controls glioblastoma stem cell plasticity

Glioblastoma (GBM) is driven by malignant neural stem-like cells that display extensive heterogeneity and phenotypic plasticity, which drive tumor progression and therapeutic resistance. Here, we show that the extracellular matrix-cell adhesion protein integrin-linked kinase (ILK) stimulates phenotypic plasticity and mesenchymal-like, invasive behavior in a murine GBM stem cell model. ILK is required for the interconversion of GBM stem cells between malignancy-associated glial-like states, and its loss produces cells that are unresponsive to multiple cell state transition cues. We further show that an ILK/STAT3 signaling pathway controls the plasticity that enables transition of GBM stem cells to an astrocyte-like state in vitro and in vivo. Finally, we find that ILK expression correlates with expression of STAT3-regulated proteins and protein signatures describing astrocyte-like and mesenchymal states in patient tumors. This work identifies ILK as a pivotal regulator of multiple malignancy-associated GBM phenotypes, including phenotypic plasticity and mesenchymal state.

Basal-to-inflammatory transition and tumor resistance via crosstalk with a pro-inflammatory stromal niche

Cancer-associated inflammation is a double-edged sword possessing both pro- and anti-tumor properties through ill-defined tumor-immune dynamics. While we previously identified a carcinoma tumor-intrinsic resistance pathway, basal-to-squamous cell carcinoma transition, here, employing a multipronged single-cell and spatial-omics approach, we identify an inflammation and therapy-enriched tumor state we term basal-to-inflammatory transition. Basal-to-inflammatory transition signature correlates with poor overall patient survival in many epithelial tumors. Basal-to-squamous cell carcinoma transition and basal-to-inflammatory transition occur in adjacent but distinct regions of a single tumor: basal-to-squamous cell carcinoma transition arises within the core tumor nodule, while basal-to-inflammatory transition emerges from a specialized inflammatory environment defined by a tumor-associated TREM1 myeloid signature. TREM1 myeloid-derived cytokines IL1 and OSM induce basal-to-inflammatory transition in vitro and in vivo through NF-κB, lowering sensitivity of patient basal cell carcinoma explant tumors to Smoothened inhibitor treatment. This work deepens our knowledge of the heterogeneous local tumor microenvironment and nominates basal-to-inflammatory transition as a drug-resistant but targetable tumor state driven by a specialized inflammatory microenvironment.

Uncovering naringin's anticancer mechanisms in glioblastoma via molecular docking and network pharmacology approaches

Naringin, a flavonoid, exhibits diverse therapeutic properties and has been proven to exert cytotoxic effects on cancer cells. Nevertheless, the precise mechanism of naringin maintaining its cytotoxic effect on glioblastoma (GBM) remains unknown. Thus, the current study aimed to establish a plausible cellular mechanism for Naringin's inhibition of GBM. We employed various system biology techniques to forecast the primary targets, including gene ontology and cluster analysis, KEGG enrichment pathway estimation, molecular docking, MD (molecular dynamic) simulation and MMPBSA analysis. Glioblastoma target sequences were obtained via DisGeNet and Therapeutic Target Prediction, aligned with naringin targets, and analyzed for gene enrichment and ontology. Gene enrichment analysis identified the top ten hub genes. Further, molecular docking was conducted on all identified targets. For molecular dynamics modelling, we selected the two complexes that exhibited the most docking affinity and the two most prominent genes of the hub identified through analysis of the enrichment of genes. The PARP1 and ALB1 signalling pathways were found to be the main regulated routes. Naringin exhibited the highest binding potential of - 12.90 kcal/mol with PARP1 (4ZZZ), followed by ABL1 (2ABL), with naringin showing a - 8.4 kcal/mol binding score, as determined by molecular docking. The molecular dynamic approach and MM-PBSA investigation along with PCA study revealed that the complex of Naringin, with 4ZZZ (PARP1) and, 2ABL (ABL1), are highly stable compared to that of imatinib and talazoparib. Analyses of the signalling pathway suggested that naringin may have anticancer effects against GBM by influencing the protein PARP and ALB1 levels. Cytotoxicity assay was performed on two different glioblastoma cell lines C6 and U87MG cells. Naringin demonstrates a higher cytotoxic potency against U87MG human glioblastoma cells compared to C6 rat glioma cells.

Let-7a-3p overexpression increases chemosensitivity to carmustine and synergistically promotes autophagy and suppresses cell survival in U87MG glioblastoma cancer cells

In terms of primary brain tumors, glioblastoma is one of the most aggressive and common brain tumors. The high resistance of glioblastoma to chemotherapy has made it vital to find alternative treatments and biological mechanisms to reduce the survival of cancer cells. Given that, the objective of the present research was to explore the potential of let-7a-3p when used in combination with carmustine in human glioblastoma cancer cells. Based on previous studies, the expression of let-7a is downregulated in the U87MG cell line. Let-7a-3p transfected into U87MG glioblastoma cells. Cell viability of the cells was assessed by MTT assay. The apoptotic induction in U87MG cancerous cells was determined through the utilization of DAPI and Annexin V/PI staining techniques. Moreover, the induction of autophagy and cell cycle arrest was evaluated by flow cytometry. Furthermore, cell migration was evaluated by the wound healing assay while colony formation assay was conducted to evaluate colony formation. Also, the expression of the relevant genes was evaluated using qRT-PCR. Transfection of let-7a-3p mimic in U87MG cells increased the expression of the miRNA and also increased the sensitivity of U87MG cells to carmustine. Let-7a-3p and carmustine induced sub-G1 and S phase cell cycle arrest, respectively. Combination treatment of let-7a-3p and carmustine synergistically increased arrested cells and induced apoptosis through regulating involved genes including P53, caspase-3, Bcl-2, and Bax. Combined treatment with let-7a-3p and carmustine also induced autophagy and increased the expression of the ATG5 and Beclin 1 (ATG6). Furthermore, let-7a-3p combined with carmustine inhibited cell migration via decreasing the expression of MMP-2. Moreover, the combination therapy decreased the ability of U87MG to form colonies through downregulating CD-44. In conclusion, our work suggests that combining let-7a-3p replacement therapy with carmustine treatment could be considered a promising strategy in treatment and can increase efficiency of glioblastoma chemotherapy.

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.

Distinct tumor-TAM interactions in IDH-stratified glioma microenvironments unveiled by single-cell and spatial transcriptomics

Tumor-associated macrophages (TAMs) residing in the tumor microenvironment (TME) are characterized by their pivotal roles in tumor progression, antitumor immunity, and TME remodeling. However, a thorough comparative characterization of tumor-TAM crosstalk across IDH-defined categories of glioma remains elusive, likely contributing to mixed outcomes in clinical trials. We delineated the phenotypic heterogeneity of TAMs across IDH-stratified gliomas. Notably, two TAM subsets with a mesenchymal phenotype were enriched in IDH-WT glioblastoma (GBM) and correlated with poorer patient survival and reduced response to anti-PD-1 immune checkpoint inhibitor (ICI). We proposed SLAMF9 receptor as a potential therapeutic target. Inference of gene regulatory networks identified PPARG, ELK1, and MXI1 as master transcription factors of mesenchymal BMD-TAMs. Our analyses of reciprocal tumor-TAM interactions revealed distinct crosstalk in IDH-WT tumors, including ANXA1-FPR1/3, FN1-ITGAVB1, VEGFA-NRP1, and TNFSF12-TNFRSF12A with known contribution to immunosuppression, tumor proliferation, invasion and TAM recruitment. Spatially resolved transcriptomics further elucidated the architectural organization of highlighted communications. Furthermore, we demonstrated significant upregulation of ANXA1, FN1, NRP1, and TNFRSF12A genes in IDH-WT tumors using bulk RNA-seq and RT-qPCR. Longitudinal expression analysis of candidate genes revealed no difference between primary and recurrent tumors indicating that the interactive network of malignant states with TAMs does not drastically change upon recurrence. Collectively, our study offers insights into the unique cellular composition and communication of TAMs in glioma TME, revealing novel vulnerabilities for therapeutic interventions in IDH-WT GBM.

Microtubule-associated NAV3 regulates invasive phenotypes in glioblastoma cells

Glioblastomas are aggressive brain tumors for which effective therapy is still lacking, resulting in dismal survival rates. These tumors display significant phenotypic plasticity, harboring diverse cell populations ranging from tumor core cells to dispersed, highly invasive cells. Neuron navigator 3 (NAV3), a microtubule-associated protein affecting microtubule growth and dynamics, is downregulated in various cancers, including glioblastoma, and has thus been considered a tumor suppressor. In this study, we challenge this designation and unveil distinct expression patterns of NAV3 across different invasion phenotypes. Using glioblastoma cell lines and patient-derived glioma stem-like cell cultures, we disclose an upregulation of NAV3 in invading glioblastoma cells, contrasting with its lower expression in cells residing in tumor spheroid cores. Furthermore, we establish an association between low and high NAV3 expression and the amoeboid and mesenchymal invasive phenotype, respectively, and demonstrate that overexpression of NAV3 directly stimulates glioblastoma invasive behavior in both 2D and 3D environments. Consistently, we observed increased NAV3 expression in cells migrating along blood vessels in mouse xenografts. Overall, our results shed light on the role of NAV3 in glioblastoma invasion, providing insights into this lethal aspect of glioblastoma behavior.

PRMT6 facilitates EZH2 protein stability by inhibiting TRAF6-mediated ubiquitination degradation to promote glioblastoma cell invasion and migration

Invasion and migration are the key hallmarks of cancer, and aggressive growth is a major factor contributing to treatment failure and poor prognosis in glioblastoma. Protein arginine methyltransferase 6 (PRMT6), as an epigenetic regulator, has been confirmed to promote the malignant proliferation of glioblastoma cells in previous studies. However, the effects of PRMT6 on glioblastoma cell invasion and migration and its underlying mechanisms remain elusive. Here, we report that PRMT6 functions as a driver element for tumor cell invasion and migration in glioblastoma. Bioinformatics analysis and glioma sample detection results demonstrated that PRMT6 is highly expressed in mesenchymal subtype or invasive gliomas, and is significantly negatively correlated with their prognosis. Inhibition of PRMT6 (using PRMT6 shRNA or inhibitor EPZ020411) reduces glioblastoma cell invasion and migration in vitro, whereas overexpression of PRMT6 produces opposite effects. Then, we identified that PRMT6 maintains the protein stability of EZH2 by inhibiting the degradation of EZH2 protein, thereby mediating the invasion and migration of glioblastoma cells. Further mechanistic investigations found that PRMT6 inhibits the transcription of TRAF6 by activating the histone methylation mark (H3R2me2a), and reducing the interaction between TRAF6 and EZH2 to enhance the protein stability of EZH2 in glioblastoma cells. Xenograft tumor assay and HE staining results showed that the expression of PRMT6 could promote the invasion of glioblastoma cells in vivo, the immunohistochemical staining results of mouse brain tissue tumor sections also confirmed the regulatory relationship between PRMT6, TRAF6, and EZH2. Our findings illustrate that PRMT6 suppresses TRAF6 transcription via H3R2me2a to enhance the protein stability of EZH2 to facilitate glioblastoma cell invasion and migration. Blocking the PRMT6-TRAF6-EZH2 axis is a promising strategy for inhibiting glioblastoma cell invasion and migration.

Photophysical Characterization and In Vitro Evaluation of α-Mangostin-Loaded HDL Mimetic Nano-Complex in LN-229 Glioblastoma Spheroid Model

Cytotoxic activity has been reported for the xanthone α-mangostin (AMN) against Glioblastoma multiforme (GBM), an aggressive malignant brain cancer with a poor prognosis. Recognizing that AMN's high degree of hydrophobicity is likely to limit its systemic administration, we formulated AMN using reconstituted high-density lipoprotein (rHDL) nanoparticles. The photophysical characteristics of the formulation, including fluorescence lifetime and steady-state anisotropy, indicated that AMN was successfully incorporated into the rHDL nanoparticles. To our knowledge, this is the first report on the fluorescent characteristics of AMN with an HDL-based drug carrier. Cytotoxicity studies in a 2D culture and 3D spheroid model of LN-229 GBM cells and normal human astrocytes showed an enhanced therapeutic index with the rHDL-AMN formulation compared to the unincorporated AMN and Temozolomide, a standard GBM chemotherapy agent. Furthermore, treatment with the rHDL-AMN facilitated a dose-dependent upregulation of autophagy and reactive oxygen species generation to a greater extent in LN-229 cells compared to astrocytes, indicating the reduced off-target toxicity of this novel formulation. These studies indicate the potential therapeutic benefits to GBM patients via selective targeting using the rHDL-AMN formulation.

Targeted Alpha Therapy for Glioblastoma: Review on In Vitro, In Vivo and Clinical Trials

Glioblastoma (GB), a prevalent and highly malignant primary brain tumour with a very high mortality rate due to its resistance to conventional therapies and invasive nature, resulting in 5-year survival rates of only 4-17%. Despite recent advancements in cancer management, the survival rates for GB patients have not significantly improved over the last 10-20 years. Consequently, there exists a critical unmet need for innovative therapies. One promising approach for GB is Targeted Alpha Therapy (TAT), which aims to selectively deliver potentially therapeutic radiation doses to malignant cells and the tumour microenvironment while minimising radiation exposure to surrounding normal tissue with or without conventional external beam radiation. This approach has shown promise in both pre-clinical and clinical settings. A review was conducted following PRISMA 2020 guidelines across Medline, SCOPUS, and Embase, identifying 34 relevant studies out of 526 initially found. In pre-clinical studies, TAT demonstrated high binding specificity to targeted GB cells, with affinity rates between 60.0% and 84.2%, and minimal binding to non-targeted cells (4.0-5.6%). This specificity significantly enhanced cytotoxic effects and improved biodistribution when delivered intratumorally. Mice treated with TAT showed markedly higher median survival rates compared to control groups. In clinical trials, TAT applied to recurrent GB (rGB) displayed varying success rates in extending overall survival (OS) and progression-free survival. Particularly effective when integrated into treatment regimens for both newly diagnosed and recurrent cases, TAT increased the median OS by 16.1% in newly diagnosed GB and by 36.4% in rGB, compared to current standard therapies. Furthermore, it was generally well tolerated with minimal adverse effects. These findings underscore the potential of TAT as a viable therapeutic option in the management of GB.

STAT3 phosphorylation inhibitor Bt354 exhibits anti-neoplastic activity in glioblastoma multiforme cells

The high mortality rate of glioblastoma multiforme (GBM), a lethal primary brain tumor, is attributable to postsurgical recurrence. STAT3, an oncogenic protein, is a signal transducer and transcription activator encourages cancer cell migration and proliferation, which results in resistance to therapy. STAT3 inhibition reduces cancer metastasis and improves patient prognosis. Bt354, a small molecule STAT inhibitor, exhibits significant cytotoxic and anti-proliferative activities against certain cancer types. Here, we demonstrated that exposure of GBM cells (U87 MG) to Bt354 had a significant, concentration-dependent growth suppression. Bt354 also induced apoptosis and downregulated the expression of the epithelial-mesenchymal transition genes. Therefore, this study suggests the potential of Bt354 for treating GBM owing to its ability to induce cytotoxicity.

Unlocking Glioblastoma Vulnerabilities with CRISPR-Based Genetic Screening

Glioblastoma (GBM) is the most common malignant brain tumor in adults. Despite advancements in treatment, the prognosis for patients with GBM remains poor due to its aggressive nature and resistance to therapy. CRISPR-based genetic screening has emerged as a powerful tool for identifying genes crucial for tumor progression and treatment resistance, offering promising targets for tumor therapy. In this review, we provide an overview of the recent advancements in CRISPR-based genetic screening approaches and their applications in GBM. We highlight how these approaches have been used to uncover the genetic determinants of GBM progression and responsiveness to various therapies. Furthermore, we discuss the ongoing challenges and future directions of CRISPR-based screening methods in advancing GBM research.

LncRNA NUTM2A-AS1 silencing inhibits glioma via miR-376a-3p/YAP1 axis

The lncRNA NUTM2A-AS1 has been shown to be dysregulated in gastric cancer, while the roles in glioma is unclear. The aim of this study was to investigate the roles and potential mechanisms of lncRNA NUTM2A-AS1 in the proliferation and apoptosis of glioma cells. The StarBase software and dual luciferase reporter assay were used to identify the relationship between lncRNA NUTM2A-AS1 and miR-376a-3p, and miR-376a-3p and YAP1. The expression of lncRNA NUTM2A-AS1, miR-376a-3p, and YAP1 in human glioma cell lines was detected by qRT-PCR. MTT and flow cytometry were used to detect the effects of lncRNA NUTM2A-AS1 or miR-376a-3p on the proliferation and apoptosis of U251 and A172 cells, respectively. In addition, changes of Bax and Bcl-2 expression in glioma cells were further verified by western blotting and qRT-PCR. The results showed that the expression of lncRNA NUTM2A-AS1 was elevated in glioma cell lines, while miR-376a-3p was decreased. LncRNA NUTM2A-AS1 was negatively correlated with miR-376a-3p. Silencing of lncRNA NUTM2A-AS1 enhanced the levels of miR-376a-3p, leading to reduced cell proliferation and increased apoptosis in glioma cells. YAP1 was a direct target of miR-376a-3p, and it was negatively regulated by miR-376a-3p in U251 and A172 cells. Further mechanistic studies suggested that miR-376a-3p reduced glioma cell proliferation and increased apoptosis by inhibiting YAP1 expression. In addition, lncRNA NUTM2A-AS1 positively regulated of YAP1 expression in glioma cells. In conclusion, silencing of lncRNA NUTM2A-AS1 inhibited proliferation and induced apoptosis in human glioma cells via the miR-376a-3p/YAP1 axis.

Heterocellular Adhesion in Cancer Invasion and Metastasis: Interactions between Cancer Cells and Cancer-Associated Fibroblasts

Cancer invasion is a requisite for the most malignant progression of cancer, that is, metastasis. The mechanisms of cancer invasion were originally studied using in vitro cell culture systems, in which cancer cells were cultured using artificial extracellular matrices (ECMs). However, conventional culture systems do not precisely recapitulate in vivo cancer invasion because the phenotypes of cancer cells in tumor tissues are strongly affected by the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are the most abundant cell type in the TME and accelerate cancer progression through invasion, metastasis, therapy resistance, and immune suppression. Thus, the reciprocal interactions between CAFs and cancer cells have been extensively studied, leading to the identification of factors that mediate cellular interactions, such as growth factors, cytokines, and extracellular vesicles. In addition, the importance of direct heterocellular adhesion between cancer cells and CAFs in cancer progression has recently been elucidated. In particular, CAFs are directly associated with cancer cells, allowing them to invade the ECM and metastasize to distant organs. In this review, we summarize the recent progress in understanding the molecular and cellular mechanisms of the direct heterocellular interaction in CAF-led cancer invasion and metastasis, with an emphasis on gastric cancer.

A simple agent-based hybrid model to simulate the biophysics of glioblastoma multiforme cells and the concomitant evolution of the oxygen field

BACKGROUND AND OBJECTIVES

Glioblastoma multiforme (GBM) is one of the most aggressive cancers of the central nervous system. It is characterized by a high mitotic activity and an infiltrative ability of the glioma cells, neovascularization and necrosis. GBM evolution entails the continuous interplay between heterogeneous cell populations, chemotaxis, and physical cues through different scales. In this work, an agent-based hybrid model is proposed to simulate the coupling of the multiscale biological events involved in the GBM invasion, specifically the individual and collective migration of GBM cells and the concurrent evolution of the oxygen field and phenotypic plasticity. An asset of the formulation is that it is conceptually and computationally simple but allows to reproduce the complexity and the progression of the GBM micro-environment at cell and tissue scales simultaneously.

METHODS

The migration is reproduced as the result of the interaction between every single cell and its micro-environment. The behavior of each individual cell is formulated through genotypic variables whereas the cell micro-environment is modeled in terms of the oxygen concentration and the cell density surrounding each cell. The collective behavior is formulated at a cellular scale through a flocking model. The phenotypic plasticity of the cells is induced by the micro-environment conditions, considering five phenotypes.

RESULTS

The model has been contrasted by benchmark problems and experimental tests showing the ability to reproduce different scenarios of glioma cell migration. In all cases, the individual and collective cell migration and the coupled evolution of both the oxygen field and phenotypic plasticity have been properly simulated. This simple formulation allows to mimic the formation of relevant hallmarks of glioblastoma multiforme, such as the necrotic cores, and to reproduce experimental evidences related to the mitotic activity in pseudopalisades.

CONCLUSIONS

In the collective migration, the survival of the clusters prevails at the expense of cell mitosis, regardless of the size of the groups, which delays the formation of necrotic foci and reduces the rate of oxygen consumption.

Current Status and Future Perspective in Glioma Invasion Research

Glioblastoma (GBM) is the most malignant brain tumor in adults and shows an extremely poor prognosis, with a median survival of 15 months [...].

Advancement of fluorescent aminopeptidase probes for rapid cancer detection-current uses and neurosurgical applications

Surgical resection is considered for most brain tumors to obtain tissue diagnosis and to eradicate or debulk the tumor. Glioma, the most common primary malignant brain tumor, generally has a poor prognosis despite the multidisciplinary treatments with radical resection and chemoradiotherapy. Surgical resection of glioma is often complicated by the obscure border between the tumor and the adjacent brain tissues and by the tumor's infiltration into the eloquent brain. 5-aminolevulinic acid is frequently used for tumor visualization, as it exhibits high fluorescence in high-grade glioma. Here, we provide an overview of the fluorescent probes currently used for brain tumors, as well as those under development for other cancers, including HMRG-based probes, 2MeSiR-based probes, and other aminopeptidase probes. We describe our recently developed HMRG-based probes in brain tumors, such as PR-HMRG, combined with the existing diagnosis approach. These probes are remarkably effective for cancer cell recognition. Thus, they can be potentially integrated into surgical treatment for intraoperative detection of cancers.

Liquid Biopsy for Glioma Using Cell-Free DNA in Cerebrospinal Fluid

Glioma is one of the most common primary central nervous system (CNS) tumors, and its molecular diagnosis is crucial. However, surgical resection or biopsy is risky when the tumor is located deep in the brain or brainstem. In such cases, a minimally invasive approach to liquid biopsy is beneficial. Cell-free DNA (cfDNA), which directly reflects tumor-specific genetic changes, has attracted attention as a target for liquid biopsy, and blood-based cfDNA monitoring has been demonstrated for other extra-cranial cancers. However, it is still challenging to fully detect CNS tumors derived from cfDNA in the blood, including gliomas, because of the unique structure of the blood-brain barrier. Alternatively, cerebrospinal fluid (CSF) is an ideal source of cfDNA and is expected to contribute significantly to the liquid biopsy of gliomas. Several successful studies have been conducted to detect tumor-specific genetic alterations in cfDNA from CSF using digital PCR and/or next-generation sequencing. This review summarizes the current status of CSF-based cfDNA-targeted liquid biopsy for gliomas. It highlights how the approaches differ from liquid biopsies of other extra-cranial cancers and discusses the current issues and prospects.

Peritumoral brain zone in glioblastoma: biological, clinical and mechanical features

Glioblastoma is a highly aggressive and invasive tumor that affects the central nervous system (CNS). With a five-year survival rate of only 6.9% and a median survival time of eight months, it has the lowest survival rate among CNS tumors. Its treatment consists of surgical resection, subsequent fractionated radiotherapy and concomitant and adjuvant chemotherapy with temozolomide. Despite the implementation of clinical interventions, recurrence is a common occurrence, with over 80% of cases arising at the edge of the resection cavity a few months after treatment. The high recurrence rate and location of glioblastoma indicate the need for a better understanding of the peritumor brain zone (PBZ). In this review, we first describe the main radiological, cellular, molecular and biomechanical tissue features of PBZ; and subsequently, we discuss its current clinical management, potential local therapeutic approaches and future prospects.

Betulinic Acid for Glioblastoma Treatment: Reality, Challenges and Perspectives

Betulinic acid is a naturally occurring compound that can be obtained through methanolic or ethanolic extraction from plant sources, as well as through chemical synthesis or microbial biotransformation. Betulinic acid has been investigated for its potential therapeutic properties, and exhibits anti-inflammatory, antiviral, antimalarial, and antioxidant activities. Notably, its ability to cross the blood-brain barrier addresses a significant challenge in treating neurological pathologies. This review aims to compile information about the impact of betulinic acid as an antitumor agent, particularly in the context of glioblastoma. Importantly, betulinic acid demonstrates selective antitumor activity against glioblastoma cells by inhibiting proliferation and inducing apoptosis, consistent with observations in other cancer types. Compelling evidence published highlights the acid's therapeutic action in suppressing the Akt/NFκB-p65 signaling cascade and enhancing the cytotoxic effects of the chemotherapeutic agent temozolomide. Interesting findings with betulinic acid also suggest a focus on researching the reduction of glioblastoma's invasiveness and aggressiveness profile. This involves modulation of extracellular matrix components, remodeling of the cytoskeleton, and secretion of proteolytic proteins. Drawing from a comprehensive review, we conclude that betulinic acid formulations as nanoparticles and/or ionic liquids are promising drug delivery approaches with the potential for translation into clinical applications for the treatment and management of glioblastoma.

The relationship between pathological brain activity and functional network connectivity in glioma patients

PURPOSE

Glioma is associated with pathologically high (peri)tumoral brain activity, which relates to faster progression. Functional connectivity is disturbed locally and throughout the entire brain, associating with symptomatology. We, therefore, investigated how local activity and network measures relate to better understand how the intricate relationship between the tumor and the rest of the brain may impact disease and symptom progression.

METHODS

We obtained magnetoencephalography in 84 de novo glioma patients and 61 matched healthy controls. The offset of the power spectrum, a proxy of neuronal activity, was calculated for 210 cortical regions. We calculated patients' regional deviations in delta, theta and lower alpha network connectivity as compared to controls, using two network measures: clustering coefficient (local connectivity) and eigenvector centrality (integrative connectivity). We then tested group differences in activity and connectivity between (peri)tumoral, contralateral homologue regions, and the rest of the brain. We also correlated regional offset to connectivity.

RESULTS

As expected, patients' (peri)tumoral activity was pathologically high, and patients showed higher clustering and lower centrality than controls. At the group-level, regionally high activity related to high clustering in controls and patients alike. However, within-patient analyses revealed negative associations between regional deviations in brain activity and clustering, such that pathologically high activity coincided with low network clustering, while regions with 'normal' activity levels showed high network clustering.

CONCLUSION

Our results indicate that pathological activity and connectivity co-localize in a complex manner in glioma. This insight is relevant to our understanding of disease progression and cognitive symptomatology.

The generation of glioma organoids and the comparison of two culture methods

BACKGROUND

The intra- and inter-tumoral heterogeneity of gliomas and the complex tumor microenvironment make accurate treatment of gliomas challenging. At present, research on gliomas mainly relies on cell lines, stem cell tumor spheres, and xenotransplantation models. The similarity between traditional tumor models and patients with glioma is very low.

AIMS

In this study, we aimed to address the limitations of traditional tumor models by generating patient-derived glioma organoids using two methods that summarized the cell diversity, histological features, gene expression, and mutant profiles of their respective parent tumors and assess the feasibility of organoids for personalized treatment.

MATERIALS AND METHODS

We compared the organoids generated using two methods through growth analysis, immunohistological analysis, genetic testing, and the establishment of xenograft models.

RESULTS

Both types of organoids exhibited rapid infiltration when transplanted into the brains of adult immunodeficient mice. However, organoids formed using the microtumor method demonstrated more similar cellular characteristics and tissue structures to the parent tumors. Furthermore, the microtumor method allowed for faster culture times and more convenient operational procedures compared to the Matrigel method.

DISCUSSION

Patient-derived glioma organoids, especially those generated through the microtumor method, present a promising avenue for personalized treatment strategies. Their capacity to faithfully mimic the cellular and molecular characteristics of gliomas provides a valuable platform for elucidating tumor biology and evaluating therapeutic modalities.

CONCLUSION

The success rates of the Matrigel and microtumor methods were 45.5% and 60.5%, respectively. The microtumor method had a higher success rate, shorter establishment time, more convenient passage and cryopreservation methods, better simulation of the cellular and histological characteristics of the parent tumor, and a high genetic guarantee.

pH-Weighted amine chemical exchange saturation transfer echo planar imaging visualizes infiltrating glioblastoma cells

BACKGROUND

Given the invasive nature of glioblastoma, tumor cells exist beyond the contrast-enhancing (CE) region targeted during treatment. However, areas of non-enhancing (NE) tumors are difficult to visualize and delineate from edematous tissue. Amine chemical exchange saturation transfer echo planar imaging (CEST-EPI) is a pH-sensitive molecular magnetic resonance imaging technique that was evaluated in its ability to identify infiltrating NE tumors and prognosticate survival.

METHODS

In this prospective study, CEST-EPI was obtained in 30 patients and areas with elevated CEST contrast ("CEST+" based on the asymmetry in magnetization transfer ratio: MTRasym at 3 ppm) within NE regions were quantitated. Median MTRasym at 3 ppm and volume of CEST + NE regions were correlated with progression-free survival (PFS). In 20 samples from 14 patients, image-guided biopsies of these areas were obtained to correlate MTRasym at 3 ppm to tumor and non-tumor cell burden using immunohistochemistry.

RESULTS

In 15 newly diagnosed and 15 recurrent glioblastoma, higher median MTRasym at 3ppm within CEST + NE regions (P = .007; P = .0326) and higher volumes of CEST + NE tumor (P = .020; P < .001) were associated with decreased PFS. CE recurrence occurred in areas of preoperative CEST + NE regions in 95.4% of patients. MTRasym at 3 ppm was correlated with presence of tumor, cell density, %Ki-67 positivity, and %CD31 positivity (P = .001; P < .001; P < .001; P = .001).

CONCLUSIONS

pH-weighted amine CEST-EPI allows for visualization of NE tumor, likely through surrounding acidification of the tumor microenvironment. The magnitude and volume of CEST + NE tumor correlates with tumor cell density, degree of proliferating or "active" tumor, and PFS.

Neuroinflammation in Glioblastoma: The Role of the Microenvironment in Tumour Progression

Glioblastoma (GBM) stands as the most aggressive and lethal among the main types of primary brain tumors. It exhibits malignant growth, infiltrating the brain tissue, and displaying resistance toward treatment. GBM is a complex disease characterized by high degrees of heterogeneity. During tumour growth, microglia and astrocytes, among other cells, infiltrate the tumour microenvironment and contribute extensively to gliomagenesis. Tumour-associated macrophages (TAMs), either of peripheral origin or representing brain-intrinsic microglia, are the most numerous nonneoplastic populations in the tumour microenvironment in GBM. The complex heterogeneous nature of GBM cells is facilitated by the local inflammatory tumour microenvironment, which mostly induces tumour aggressiveness and drug resistance. The immunosuppressive tumour microenvironment of GBM provides multiple pathways for tumour immune evasion, contributing to tumour progression. Additionally, TAMs and astrocytes can contribute to tumour progression through the release of cytokines and activation of signalling pathways. In this review, we summarize the role of the microenvironment in GBM progression, focusing on neuroinflammation. These recent advancements in research of the microenvironment hold the potential to offer a promising approach to the treatment of GBM in the coming times.

Roles of lncRNA-MALAT1 in the Progression and Prognosis of Gliomas

Long noncoding RNAs (lncRNAs) represent a large subgroup of RNA transcripts that lack the function of coding proteins and may be essential universal genes involved in carcinogenesis and metastasis. LncRNA metastasis-associated lung adenocarcinoma transcript 1 (lncRNAMALAT1) is overexpressed in various human tumors, including gliomas. However, the biological function and molecular mechanism of action of lncRNA-MALAT1 in gliomas have not yet been systematically elucidated. Accumulating evidence suggests that the abnormal expression of lncRNA-MALAT1 in gliomas is associated with various physical properties of the glioma, such as tumor growth, metastasis, apoptosis, drug resistance, and prognosis. Furthermore, lncRNAs, as tumor progression and prognostic markers in gliomas, may affect tumorigenesis, proliferation of glioma stem cells, and drug resistance. In this review, we summarize the knowledge on the biological functions and prognostic value of lncRNA-MALAT1 in gliomas. This mini-review aims to deepen the understanding of lncRNA-MALAT1 as a novel potential therapeutic target for the individualized precision treatment of gliomas.

Metabotropic Glutamate Receptors Type 3 and 5 Feature the "NeuroTransmitter-type" of Glioblastoma: A Bioinformatic Approach

BACKGROUND

Glioblastoma (GBM) represents an aggressive and common tumor of the central nervous system. The prognosis of GBM is poor, and despite a refined genetic and molecular characterization, pharmacological treatment is largely suboptimal.

OBJECTIVE

Contribute to defining a therapeutic line in GBM targeting the mGlu3 receptor in line with the principles of precision medicine.

METHODS

Here, we performed a computational analysis focused on the expression of type 3 and 5 metabotropic glutamate receptor subtypes (mGlu3 and mGlu5, respectively) in high- and low-grade gliomas.

RESULTS

The analysis allowed the identification of a particular high-grade glioma type, characterized by a high expression level of both receptor subtypes and by other markers of excitatory and inhibitory neurotransmission. This so-called neurotransmitter-GBM (NT-GBM) also shows a distinct immunological, metabolic, and vascularization gene signature.

CONCLUSION

Our findings might lay the groundwork for a targeted therapy to be specifically applied to this putative novel type of GBM.

Integrin-αvβ3 is a Therapeutically Targetable Fundamental Factor in Medulloblastoma Tumorigenicity and Radioresistance

Medulloblastoma is one of the most prevalent solid tumors found in children, occurring in the brain's posterior fossa. The standard treatment protocol involves maximal resection surgery followed by craniospinal irradiation and chemotherapy. Despite a long-term survival rate of 70%, wide disparities among patients have been observed. The identification of pertinent targets for both initial and recurrent medulloblastoma cases is imperative. Both primary and recurrent medulloblastoma are marked by their aggressive infiltration into surrounding brain tissue, robust angiogenesis, and resistance to radiotherapy. While the significant role of integrin-αvβ3 in driving these characteristics has been extensively documented in glioblastoma, its impact in the context of medulloblastoma remains largely unexplored. Integrin-αvβ3 was found to be expressed in a subset of patients with medulloblastoma. We investigated the role of integrin-αvβ3 using medulloblastoma-derived cell lines with β3-subunit depletion or overexpression both in vitro and in vivo settings. By generating radioresistant medulloblastoma cell lines, we uncovered an increased integrin-αvβ3 expression, which correlated with increased susceptibility to pharmacologic integrin-αvβ3 inhibition with cilengitide, a competitive ligand mimetic. Finally, we conducted single-photon emission computed tomography (SPECT)/MRI studies on orthotopic models using a radiolabeled integrin-αvβ3 ligand (99mTc-RAFT-RGD). This innovative approach presents the potential for a novel predictive imaging technique in the realm of medulloblastoma. Altogether, our findings lay the foundation for employing SPECT/MRI to identify a specific subset of patients with medulloblastoma eligible for integrin-αvβ3-directed therapies. This breakthrough offers a pathway toward more targeted and effective interventions in the treatment of medulloblastoma.

SIGNIFICANCE

This study demonstrates integrin-αvβ3's fundamental role in medulloblastoma tumorigenicity and radioresistance and the effect of its expression on cilengitide functional activity.

Iron inhibits glioblastoma cell migration and polarization

Glioblastoma is one of the deadliest malignancies facing modern oncology today. The ability of glioblastoma cells to diffusely spread into neighboring healthy brain makes complete surgical resection nearly impossible and contributes to the recurrent disease faced by most patients. Although research into the impact of iron on glioblastoma has addressed proliferation, there has been little investigation into how cellular iron impacts the ability of glioblastoma cells to migrate-a key question, especially in the context of the diffuse spread observed in these tumors. Herein, we show that increasing cellular iron content results in decreased migratory capacity of human glioblastoma cells. The decrease in migratory capacity was accompanied by a decrease in cellular polarization in the direction of movement. Expression of CDC42, a Rho GTPase that is essential for both cellular migration and establishment of polarity in the direction of cell movement, was reduced upon iron treatment. We then analyzed a single-cell RNA-seq dataset of human glioblastoma samples and found that cells at the tumor periphery had a gene signature that is consistent with having lower levels of cellular iron. Altogether, our results suggest that cellular iron content is impacting glioblastoma cell migratory capacity and that cells with higher iron levels exhibit reduced motility.

Treatment of glioblastoma in Greenlandic patients

Glioblastoma (GBM), WHO grade IV, is the most common primary malignant brain tumour among adults with a devastating overall survival of 14-22 months. Standard treatment of GBM includes maximum safe resection, radiotherapy plus concomitant and adjuvant temozolomide (TMZ), given over a period of approximately 9 months. Treatment and follow-up for Greenlandic patients with GBM are managed at Rigshospitalet (RH), Copenhagen. Greenlandic GBM patients, therefore, travel back and forth to RH, often unaccompanied, and challenged by cognitive failure or other symptoms from their disease and/or treatment. Few Greenlandic patients are diagnosed with GBM annually, but considering the poor prognosis and short remaining lifespan, it would be preferable to limit their travels. TMZ is administrated as capsules. Health personnel at Queen Ingrid's Hospital (DIH), Nuuk, are trained in treating other oncological diseases and handling side effects. Hence, it could be investigated whether administration of adjuvant TMZ at DIH could be feasible after personnel education as well as economic consideration and compensation, in close collaboration with neuro oncologists at RH. In this article, we describe the Greenlandic cancer treatment, and the typical workflow from diagnosis of GBM to treatment to progression.

Acquired temozolomide resistance instructs patterns of glioblastoma behavior in gelatin hydrogels

Acquired drug resistance in glioblastoma (GBM) presents a major clinical challenge and is a key factor contributing to abysmal prognosis, with less than 15 months median overall survival. Aggressive chemotherapy with the frontline therapeutic, temozolomide (TMZ), ultimately fails to kill residual highly invasive tumor cells after surgical resection and radiotherapy. Here, we report a three-dimensional (3D) engineered model of acquired TMZ resistance using two isogenically-matched sets of GBM cell lines encapsulated in gelatin methacrylol hydrogels. We benchmark response of TMZ-resistant vs. TMZ-sensitive GBM cell lines within the gelatin-based extracellular matrix platform and further validate drug response at physiologically relevant TMZ concentrations. We show changes in drug sensitivity, cell invasion, and matrix-remodeling cytokine production as the result of acquired TMZ resistance. This platform lays the foundation for future investigations targeting key elements of the GBM tumor microenvironment to combat GBM's devastating impact by advancing our understanding of GBM progression and treatment response to guide the development of novel treatment strategies.

Teaser

A hydrogel model to investigate the impact of acquired drug resistance on functional response in glioblastoma.

Design, synthesis and evaluation of novel pyrimidinylaminothiophene derivatives as FGFR1 inhibitors against human glioblastoma multiforme

Vascular endothelial growth factor receptors (VEGFRs) have emerged as the most promising anti-angiogenic therapeutic targets for the treatment of recurrent glioblastomas (GBM). However, anti-VEGF treatments led to the high proportion of non-responder patients or non lasting clinical response and the tumor progression to the greater malignant stage. To overcome these problems, there is an utmost need to develop innovative anti-angiogenic therapies. In this study, we report the development of a series of new FGFR1 inhibitors. Among them, compound 4i was able to potently inhibit FGFR1 kinase activities both in vitro and in vivo. This compound displayed strong anti-angiogenic activity in HUVECs and anti-tumor growth and anti-invasion effects in U-87MG cell line. These results emphasize the importance of FGFR1-mediated signaling pathways in GBM and reveal that pharmacological inhibition of FGFR1 can enhance the anti-tumoral, anti-angiogenic and anti-metastatic efficiency against GBM. These data support targeting of FGFR1 as a novel anti-angiogenic strategy and highlight the potential of compound 4i as a promising anti-angiogenic and anti-metastatic candidate for GBM therapy.

Role of UBE2C in Brain Cancer Invasion and Dissemination

Glioblastoma (GB) and brain metastases (BM) are the most common brain tumors in adults and are invariably associated with a dismal outcome. These highly malignant tumors share common features including increased invasion and migration of the primary or metastatic brain cancer cells, whose triggering mechanisms are largely unknown. Emerging evidence has suggested that the ubiquitin-conjugating enzyme E2C (UBE2C), essential for controlling cell cycle progression, is overexpressed in diverse malignancies, including brain cancer. This review highlights the crucial role of UBE2C in brain tumorigenesis and its association with higher proliferative phenotype and histopathological grade, with autophagy and apoptosis suppression, epithelial-to-mesenchymal transition (EMT), invasion, migration, and dissemination. High expression of UBE2C has been associated with patients' poor prognosis and drug resistance. UBE2C has also been proven as a promising therapeutic target, despite the lack of specific inhibitors. Thus, there is a need to further explore the role of UBE2C in malignant brain cancer and to develop effective targeted therapies for patients with this deadly disease.

Pharmacogenomic Analysis of Combined Therapies against Glioblastoma Based on Cell Markers from Single-Cell Sequencing

Glioblastoma is the most common and aggressive form of primary brain cancer and the lack of viable treatment options has created an urgency to develop novel treatments. Personalized or predictive medicine is still in its infancy stage at present. This research aimed to discover biomarkers to inform disease progression and to develop personalized prophylactic and therapeutic strategies by combining state-of-the-art technologies such as single-cell RNA sequencing, systems pharmacology, and a polypharmacological approach. As predicted in the pyroptosis-related gene (PRG) transcription factor (TF) microRNA (miRNA) regulatory network, TP53 was the hub gene in the pyroptosis process in glioblastoma (GBM). A LASSO Cox regression model of pyroptosis-related genes was built to accurately and conveniently predict the one-, two-, and three-year overall survival rates of GBM patients. The top-scoring five natural compounds were parthenolide, rutin, baeomycesic acid, luteolin, and kaempferol, which have NFKB inhibition, antioxidant, lipoxygenase inhibition, glucosidase inhibition, and estrogen receptor agonism properties, respectively. In contrast, the analysis of the cell-type-specific differential expression-related targets of natural compounds showed that the top five subtype cells targeted by natural compounds were endothelial cells, microglia/macrophages, oligodendrocytes, dendritic cells, and neutrophil cells. The current approach-using the pharmacogenomic analysis of combined therapies-serves as a model for novel personalized therapeutic strategies for GBM treatment.

Synergism of d-limonene and temozolomide on migratory and apoptotic behaviors of human glioblastoma cell lines

Introduction

Glioblastoma (GBM), which is a heterogeneous and aggressive type of brain tumor, is known for its poor survival outcomes. The treatment of GBM remains challenging primarily due to the drug resistance to the current standard therapeutic option, temozolomide (TMZ). Researchers are currently focusing on developing an appropriate alternative combinatorial therapeutic to enhance treatment outcomes. D-limonene (DL) is a monoterpene derived from citrus fruit. This study aims to assess the impact of combining DL with TMZ and explore its potential mechanism of action in U87MG and LN229 GBM cells.

Methods

The effects of the combined treatment of DL and TMZ were assessed on various cellular aspects, including cell viability, anchorage-independent cell growth, and DNA damage. Furthermore, the influence of this combination on cell cycle progression, cell migration, and cell death was also investigated.

Results

The combination of DL+TMZ demonstrated a synergistic effect, resulting in reduced cell proliferation and suppressing the colony formation ability of a single cell. Treatment with DL and TMZ arrested the cells in G0/G1 phase. Furthermore, the DL+TMZ combination induced apoptosis by upregulating the expression of Bax, and Caspase (CASP)-3, while reducing the expression of the Bcl-2 gene in GBM cells. In addition, the combined treatment of DL+TMZ significantly decreased the expression of matrix metalloproteinase (MMP)-2 and MMP-9, expression, indicating inhibition of cell migration in GBM cells.

Conclusion

In conclusion, the combination of DL and TMZ demonstrated a synergistic effect in reducing cell proliferation, suppressing colony formation, inducing apoptosis, and inhibiting cell migration in GBM cells. These findings suggest the potential of DL+TMZ combination therapy as an effective treatment for GBM.

Invadopodia associated Thrombospondin-1 contributes to a post-therapy pro-invasive response in glioblastoma cells

A critical challenge in the treatment of glioblastoma (GBM) is its highly invasive nature which promotes cell migration throughout the brain and hinders surgical resection and effective drug delivery. GBM cells demonstrate augmented invasive capabilities following exposure to the current gold standard treatment of radiotherapy (RT) and concomitant and adjuvant temozolomide (TMZ), resulting in rapid disease recurrence. Elucidating the mechanisms employed by post-treatment invasive GBM cells is critical to the development of more effective therapies. In this study, we utilized a Nanostring® Cancer Progression gene expression panel to identify candidate genes that may be involved in enhanced GBM cell invasion after treatment with clinically relevant doses of RT/TMZ. Our findings identified thrombospondin-1 (THBS1) as a pro-invasive gene that is upregulated in these cells. Immunofluorescence staining revealed that THBS1 localised within functional matrix-degrading invadopodia that formed on the surface of GBM cells. Furthermore, overexpression of THBS1 resulted in enhanced GBM cell migration and secretion of MMP-2, which was reduced with silencing of THBS1. The preliminary data demonstrates that THBS1 is associated with invadopodia in GBM cells and is likely involved in the invadopodia-mediated invasive process in GBM cells exposed to RT/TMZ treatment. Therapeutic inhibition of THBS1-mediated invadopodia activity, which facilitates GBM cell invasion, should be further investigated as a treatment for GBM.

Effect of Dimeric Disintegrins Isolated from Vipera lebetina obtusa Venom on Glioblastoma Cellular Responses

Integrins play a fundamental role in the migration and invasiveness of glioblastoma (GBM) cells, making them suitable targets for innovative cancer therapy. The aim of this study was to evaluate the effect of the RGD homodimeric disintegrin VLO4, isolated from Vipera lebetina obtusa venom, on the adhesion, spreading, migration, and survival of LBC3, LN18, and LN229 cell lines. This disintegrin, as a potent antagonist for α5β1 integrin, showed pro-adhesive properties for these cell lines, the highest for LN229 and the lowest for LBC3. Glioblastoma cells displayed significant differences in the spreading on the immobilized VLO4 and the natural α5β1 integrin ligand, fibronectin. Solubilized VLO4 showed different cytotoxicity and pro-apoptotic properties among tested cell lines, with the highest against LN18 and none against LN229. Moreover, VLO4 revealed an inhibitory effect on the migration of LBC3 and LN18 cell lines, in contrast to LN229 cells, which were not sensitive to this disintegrin. However, LN229 migration was impaired by VLO5, a disintegrin antagonistic to integrin α9β1, used in combination with VLO4. A possible mechanism of action of VLO4 may be related to the downregulation of α5β1 integrin subunit expression, as revealed by Western blot. VLO4 also inhibited cell proliferation and induced caspase-dependent apoptosis in LBC3 and LN18 cell lines. These results indicate that targeting α5β1 integrin by related VLO4 compounds may be useful in the development of integrin-targeted therapy for glioblastoma.

3D-Printed Tumor-on-a-Chip Model for Investigating the Effect of Matrix Stiffness on Glioblastoma Tumor Invasion

Glioblastoma multiform (GBM) tumor progression has been recognized to be correlated with extracellular matrix (ECM) stiffness. Dynamic variation of tumor ECM is primarily regulated by a family of enzymes which induce remodeling and degradation. In this paper, we investigated the effect of matrix stiffness on the invasion pattern of human glioblastoma tumoroids. A 3D-printed tumor-on-a-chip platform was utilized to culture human glioblastoma tumoroids with the capability of evaluating the effect of stiffness on tumor progression. To induce variations in the stiffness of the collagen matrix, different concentrations of collagenase were added, thereby creating an inhomogeneous collagen concentration. To better understand the mechanisms involved in GBM invasion, an in silico hybrid mathematical model was used to predict the evolution of a tumor in an inhomogeneous environment, providing the ability to study multiple dynamic interacting variables. The model consists of a continuum reaction-diffusion model for the growth of tumoroids and a discrete model to capture the migration of single cells into the surrounding tissue. Results revealed that tumoroids exhibit two distinct patterns of invasion in response to the concentration of collagenase, namely ring-type and finger-type patterns. Moreover, higher concentrations of collagenase resulted in greater invasion lengths, confirming the strong dependency of tumor behavior on the stiffness of the surrounding matrix. The agreement between the experimental results and the model's predictions demonstrates the advantages of this approach in investigating the impact of various extracellular matrix characteristics on tumor growth and invasion.

Supramaximal Resection Can Prolong the Survival of Patients with Cortical Glioblastoma: A Volumetric Study

We aimed to retrospectively determine the resection rate of fluid-attenuated inversion recovery (FLAIR) lesions to evaluate the clinical effects of supramaximal resection (SMR) on the survival of patients with glioblastoma (GBM). Thirty-three adults with newly diagnosed GBM who underwent gross total tumor resection were enrolled. The tumors were classified into cortical and deep-seated groups according to their contact with the cortical gray matter. Pre- and postoperative FLAIR and gadolinium-enhanced T1-weighted imaging tumor volumes were measured using a three-dimensional imaging volume analyzer, and the resection rate was calculated. To evaluate the association between SMR rate and outcome, we subdivided patients whose tumors were totally resected into the SMR and non-SMR groups by moving the threshold value of SMR in 10% increments from 0% and compared their overall survival (OS) change. An improvement in OS was observed when the threshold value of SMR was 30% or more. In the cortical group (n = 23), SMR (n = 8) tended to prolong OS compared with gross total resection (GTR) (n = 15), with the median OS of 69.6 and 22.1 months, respectively (p = 0.0945). Contrastingly, in the deep-seated group (n = 10), SMR (n = 4) significantly shortened OS compared with GTR (n = 6), with median OS of 10.2 and 27.9 months, respectively (p = 0.0221). SMR could help prolong OS in patients with cortical GBM when 30% or more volume reduction is achieved in FLAIR lesions, although the impact of SMR for deep-seated GBM must be validated in larger cohorts.

FOXO1-miR-506 axis promotes chemosensitivity to temozolomide and suppresses invasiveness in glioblastoma through a feedback loop of FOXO1/miR-506/ETS1/FOXO1

To explore the role of forkhead box protein O1 (FOXO1) in the progression of glioblastoma multiforme (GBM) and related drug resistance, we deciphered the roles of FOXO1 and miR-506 in proliferation, apoptosis, migration, invasion, autophagy, and temozolomide (TMZ) sensitivity in the U251 cell line using in vitro and in vivo experiments. Cell viability was tested by a cell counting kit-8 (CCK8) kit; migration and invasion were checked by the scratching assay; apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining and flow cytometry. The construction of plasmids and dual-luciferase reporter experiment were carried out to find the interaction site between FOXO1 and miR-506. Immunohistochemistry was done to check the protein level in tumors after the in vivo experiment. We found that the FOXO1-miR-506 axis suppresses GBM cell invasion and migration and promotes GBM chemosensitivity to TMZ, which was mediated by autophagy. FOXO1 upregulates miR-506 by binding to its promoter to enhance transcriptional activation. MiR-506 could downregulate E26 transformation-specific 1 (ETS1) expression by targeting its 3'-untranslated region (UTR). Interestingly, ETS1 promoted FOXO1 translocation from the nucleus to the cytosol and further suppressed the FOXO1-miR-506 axis in GBM cells. Consistently, both miR-506 inhibition and ETS1 overexpression could rescue FOXO1 overactivation-mediated TMZ chemosensitivity in mouse models. Our study demonstrated a negative feedback loop of FOXO1/miR-506/ETS1/FOXO1 in GBM in regulating invasiveness and chemosensitivity. Thus, the above axis might be a promising therapeutic target for GBM.

An anti-glioblastoma gold(i)-NHC complex distorts mitochondrial morphology and bioenergetics to induce tumor growth inhibition

Glioblastoma multiforme (GBM) is the most lethal brain cancer subtype, often advanced by the time of initial diagnosis. Existing treatment modalities including surgery, chemotherapy and radiation have been stymied by recurrence, metastasis, drug resistance and brain targetability. Here, we report a geometrically distinct Au(i) complex ligated by N^N-bidentate ligands and supported by a N-heterocyclic ligand that modulates mitochondrial morphology to inhibit GBM in vitro and in vivo. This work benefits from the facile preparation of anti-GBM Au(i)-NHC complexes.

A complex of Wnt/planar cell polarity signaling components Vangl1 and Fzd7 drives glioblastoma multiforme malignant properties

Targeting common oncogenic drivers of glioblastoma multiforme (GBM) in patients has remained largely ineffective, raising the possibility that alternative pathways may contribute to tumor aggressiveness. Here we demonstrate that Vangl1 and Fzd7, components of the non-canonical Wnt planar cell polarity (Wnt/PCP) signaling pathway, promote GBM malignancy by driving cellular proliferation, migration, and invasiveness, and engage Rho GTPases to promote cytoskeletal rearrangements and actin dynamics in migrating GBM cells. Mechanistically, we uncover the existence of a novel Vangl1/Fzd7 complex at the leading edge of migrating GBM cells and propose that this complex is critical for the recruitment of downstream effectors to promote tumor progression. Moreover, we observe that depletion of FZD7 results in a striking suppression of tumor growth and latency and extends overall survival in an intracranial mouse xenograft model. Our observations support a novel mechanism by which Wnt/PCP components Vangl1 and Fzd7 form a complex at the leading edge of migratory GBM cells to engage downstream effectors that promote actin cytoskeletal rearrangements dynamics. Our findings suggest that interference with Wnt/PCP pathway function may offer a novel therapeutic strategy for patients diagnosed with GBM.

Autophagy Inhibition with Chloroquine Increased Pro-Apoptotic Potential of New Aziridine-Hydrazide Hydrazone Derivatives against Glioblastoma Cells

Tumor therapy escape due to undesired side effects induced by treatment, such as prosurvival autophagy or cellular senescence, is one of the key mechanisms of resistance that eventually leads to tumor dormancy and recurrence. Glioblastoma is the most frequent and practically incurable neoplasm of the central nervous system; thus, new treatment modalities have been investigated to find a solution more effective than the currently applied standards based on temozolomide. The present study examined the newly synthesized compounds of aziridine-hydrazide hydrazone derivatives to determine their antineoplastic potential against glioblastoma cells in vitro. Although the output of our investigation clearly demonstrates their proapoptotic activity, the cytotoxic effect appeared to be blocked by treatment-induced autophagy, the phenomenon also detected in the case of temozolomide action. The addition of an autophagy inhibitor, chloroquine, resulted in a significant increase in apoptosis triggered by the tested compounds, as well as temozolomide. The new aziridine-hydrazide hydrazone derivatives, which present cytotoxic potential against glioblastoma cells comparable to or even higher than that of temozolomide, show promising results and, thus, should be further investigated as antineoplastic agents. Moreover, our findings suggest that the combination of an apoptosis inducer with an autophagy inhibitor could optimize chemotherapeutic efficiency, and the addition of an autophagy inhibitor should be considered as an optional adjunctive therapy minimizing the risk of tumor escape from treatment.

Asymmetric mitosis contributes to different migratory performance in sister cells

In cancer, cell migration contributes to the spread of tumor cells resulting in metastasis. Heterogeneity in the migration capacity can produce individual cells with heightened capacity leading to invasion and metastasis. Our hypothesis is that cell migration characteristics can divide asymmetrically in mitosis, allowing a subset of cells to have a larger contribution to invasion and metastasis. Therefore, our aim is to elucidate whether sister cells have different migratory capacity and analyze if this difference is defined by mitosis. Through time-lapse videos, we analyzed migration speed, directionality, maximum displacement of each trajectory, and velocity as well as cell area and polarity and then compared the values between mother-daughter cells and between sister cells of three tumor cell lines (A172, MCF7, SCC25) and two normal cell lines (MRC5 and CHO·K1 cells). We observed that daughter cells had a different migratory phenotype compared to their mothers, and one single mitosis is enough for the sisters behave like nonrelated cells. However, mitosis did not influence cell area and polarity dynamics. These findings indicates that migration performance is not heritable, and that asymmetric cell division might have an important impact on cancer invasion and metastasis, by producing cells with different migratory capacity.

Remote neuronal activity drives glioma progression through SEMA4F

The tumour microenvironment plays an essential role in malignancy, and neurons have emerged as a key component of the tumour microenvironment that promotes tumourigenesis across a host of cancers1,2. Recent studies on glioblastoma (GBM) highlight bidirectional signalling between tumours and neurons that propagates a vicious cycle of proliferation, synaptic integration and brain hyperactivity3-8; however, the identity of neuronal subtypes and tumour subpopulations driving this phenomenon is incompletely understood. Here we show that callosal projection neurons located in the hemisphere contralateral to primary GBM tumours promote progression and widespread infiltration. Using this platform to examine GBM infiltration, we identified an activity-dependent infiltrating population present at the leading edge of mouse and human tumours that is enriched for axon guidance genes. High-throughput, in vivo screening of these genes identified SEMA4F as a key regulator of tumourigenesis and activity-dependent progression. Furthermore, SEMA4F promotes the activity-dependent infiltrating population and propagates bidirectional signalling with neurons by remodelling tumour-adjacent synapses towards brain network hyperactivity. Collectively our studies demonstrate that subsets of neurons in locations remote to primary GBM promote malignant progression, and also show new mechanisms of glioma progression that are regulated by neuronal activity.

Single-cell RNA sequencing identifies critical transcription factors of tumor cell invasion induced by hypoxia microenvironment in glioblastoma

Rationale: Glioblastoma (GBM) is an aggressive malignant primary brain cancer with poor survival. Hypoxia is a hallmark of GBM, which promotes tumor cells spreading (invasion) into the healthy brain tissue. Methods: To better elucidate the influence of hypoxia on GBM invasion, we proposed a data-driven modeling framework for predicting cellular hypoxia (CHPF) by integrating single cell transcriptome profiling and hypoxia gene signatures. Results: We characterized the hypoxia status landscape of GBM cells and observed that hypoxic cells were only present in the tumor core. Then, by investigating the cell-cell communication between immune cells and tumor cells, we discovered significant interaction between macrophages and tumor cells in hypoxic microenvironment. Notably, we dissected the functional heterogeneity of tumor cells and identified a hypoxic subpopulation that had highly invasive potential. By constructing cell status specific gene regulatory networks, we further identified 14 critical regulators of tumor invasion induced by hypoxic microenvironment. Finally, we confirmed that knocking down two critical regulators CEBPD and FOSL1 could reduce the invasive ability of GBM under hypoxic conditions. Additionally, we revealed the therapeutic effect of Axitinib and Entinostat through the mice model. Conclusion: Our work revealed the critical regulators in hypoxic subpopulation with high invasive potential in GBM, which may have practical implications for clinical targeted-hypoxia cancer drug therapy.

In Vitro and In Vivo Drug-Response Profiling Using Patient-Derived High-Grade Glioma

BACKGROUND

Genomic profiling cannot solely predict the complexity of how tumor cells behave in their in vivo microenvironment and their susceptibility to therapies. The aim of the study was to establish a functional drug prediction model utilizing patient-derived GBM tumor samples for in vitro testing of drug efficacy followed by in vivo validation to overcome the disadvantages of a strict pharmacogenomics approach.

METHODS

High-throughput in vitro pharmacologic testing of patient-derived GBM tumors cultured as 3D organoids offered a cost-effective, clinically and phenotypically relevant model, inclusive of tumor plasticity and stroma. RNAseq analysis supplemented this 128-compound screening to predict more efficacious and patient-specific drug combinations with additional tumor stemness evaluated using flow cytometry. In vivo PDX mouse models rapidly validated (50 days) and determined mutational influence alongside of drug efficacy. We present a representative GBM case of three tumors resected at initial presentation, at first recurrence without any treatment, and at a second recurrence following radiation and chemotherapy, all from the same patient.

RESULTS

Molecular and in vitro screening helped identify effective drug targets against several pathways as well as synergistic drug combinations of cobimetinib and vemurafenib for this patient, supported in part by in vivo tumor growth assessment. Each tumor iteration showed significantly varying stemness and drug resistance.

CONCLUSIONS

Our integrative model utilizing molecular, in vitro, and in vivo approaches provides direct evidence of a patient's tumor response drifting with treatment and time, as demonstrated by dynamic changes in their tumor profile, which may affect how one would address that drift pharmacologically.