Glioma Invasion Research Articles

High expression of SIGLEC7 may promote M2-type macrophage polarization leading to adverse prognosis in glioma patients.

Gliomas are the most common primary intracranial tumors, known for their high invasiveness and destructiveness. Sialic acid-binding immunoglobulin-like lectin 7 (SIGLEC7) is present in various immune cells, especially macrophages, and significantly affects immune homeostasis and cancer cell response. However, research on the role and prognostic impact of SIGLEC7 in glioma patients is currently limited. We utilized transcriptomic data from 702 glioma patients in The Cancer Genome Atlas (TCGA) and 693 glioma patients in the Chinese Glioma Genome Atlas (CGGA), along with clinical samples we collected, to comprehensively investigate the impact of SIGLEC7 on glioma expression patterns, biological functions, and prognostic value. We focused on its role in glioma-related immune responses and immune cell infiltration and analyzed its expression at the single-cell level. Finally, we validated the role of SIGLEC7 in gliomas through tissue and cell experiments. SIGLEC7 expression was significantly increased in glioma patients with malignant characteristics. Survival analysis indicated that glioma patients with high SIGLEC7 expression had significantly lower survival rates. Gene function analysis revealed that SIGLEC7 is primarily involved in immune and inflammatory responses and is strongly negatively correlated with tumor-associated immune regulation. Additionally, the expression of most immune checkpoints was positively correlated with SIGLEC7, and immune cell infiltration analysis clearly demonstrated a significant positive correlation between SIGLEC7 expression and M2 macrophage infiltration levels. Single-cell analysis, along with tissue and cell experiments, confirmed that SIGLEC7 enhances macrophage polarization towards the M2 phenotype, thereby promoting glioma invasiveness through the immunosuppressive effects of M2 macrophages. Cox regression analysis and the establishment of survival prediction models indicated that high SIGLEC7 expression is an unfavorable prognostic factor for glioma patients. High SIGLEC7 expression predicts poor prognosis in glioma patients and is closely associated with M2 macrophages in the tumor environment. In the future, SIGLEC7 may become a promising target for glioma immunotherapy.

Expression, Prognostic Value, and Biological Function of CTHRC1 in Different Types of Gliomas: A Bioinformatic Analysis and Experiment Validation.

In recent years, abnormal expression of collagen triple helix repeat containing 1 (CTHRC1) has been found in some tumors, closely related to the poor prognosis of cancer patients. However, the clinical significance of CTHRC1 in gliomas is not completely understood. We investigated the expression, prognostic value, and potential biological function of CTHRC1 in different types of gliomas through bioinformatics analysis and experimental verification. Bioinformatics analysis revealed several key findings regarding the expression and clinical significance of CTHRC1 in gliomas. First, the analysis demonstrated a positive correlation between CTHRC1 expression and the World Health Organization (WHO) grading of gliomas, a relationship that was validated through immunohistochemistry experiments. In addition, a trend was observed in which CTHRC1 expression increased with the extent of glioma invasion, as supported by Western blot experiments. Subsequent bioinformatics analysis identified the mesenchymal subtype of gliomas as having the highest levels of CTHRC1 expression, a finding reinforced by immunohistochemical staining. Moreover, high CTHRC1 expression was associated with poor prognosis in gliomas and emerged as an independent prognostic factor, with varying impacts on prognosis between low-grade gliomas (LGGs) and glioblastoma (GBM) subgroups. Notably, comparative analysis unveiled distinct patterns of immune infiltration of CTHRC1 in LGG and GBM. Furthermore, alterations in copy number variations and DNA methylation were identified as potential mechanisms underlying elevated CTHRC1 levels in gliomas. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis indicated that CTHRC1 and its associated genes mainly function in the extracellular matrix and participate in tumor-related signaling pathways. The CTHRC1 has shown significant clinical utility as a prognostic marker and mesenchymal subtype marker of glioma.

Cortico-cortical evoked potentials of the arcuate fascicle in minimally invasive glioma surgery guided by Penfield stimulation

Cortico-cortical evoked potentials of the arcuate fascicle in minimally invasive glioma surgery guided by Penfield stimulation

Preclinical Experimental Models for Human Glioma

Gliomas are one of the most common incurable brain tumors in adults with poor prognosis. Attempts at modeling human gliomas over the past decades have not only improved our knowledge of glioma biology but also boosted the development of therapeutic strategies. Despite great endeavors, gliomas are not responsive to the current tumor treatments, such as radiotherapy, chemotherapy, and immunotherapy due to their high inter- and intra-heterogenic tumor microenvironment (TME) and immune suppressive landscape. Therefore, it is significant to utilize suitable models to investigate the tumorigenesis, progression, and invasion of gliomas and evaluate potential therapies. Ideally, glioma models should fully recapitulate the genetic alterations and histological characteristics of the parental tumor, as well as reproduce the interactions between the tumor and its TME. In this review, we will discuss and compare the pros and cons of the current glioma models including traditional mouse models, established cell lines, newly 3D-cultured organoids, and 3D bioprinting glioma models in glioma pathogenesis research and therapy evaluation.

10082-RT-1 LONG-TERM RESULTS OF A BNCT PHASE II CLINICAL TRIAL USING AN ACCELERATOR-BASED NEUTRON SOURCE FOR PATIENTS WITH RECURRENT GLIOBLASTOMA

Abstract PURPOSE Accelerator-based neutron sources have received regulatory approval and boron neutron capture therapy (BNCT) for head and neck cancer has been introduced into clinical treatment in earnest. BNCT is a radiotherapy with cell-selective characteristics, and its application to highly invasive malignant gliomas (MG) is the origin of its development. This study reports the long-term results of a phase II study of accelerator-based BNCT (AB-BNCT) using a cyclotron-based neutron source (BNCT30) and a boronophenylalanine product (SPM-011) in patients with recurrent MG. METHODS A phase 2 clinical trial (JG002) in 27 patients with recurrent malignant glioma (MG) (24 with glioblastoma (GB)) was conducted using SPM-011 and BNCT30. Eligibility criteria were radiation re-irradiation with MG not previously treated with bevacizumab and patients relapsing after standard of care (radiotherapy and chemotherapy with temozolomide). The primary endpoint was one-year survival from BNCT treatment, and secondary endpoints included median overall survival (mOS) and median progression-free survival (mPFS). The 1-year survival and mOS of patients with relapsed GB in JG002 were 79.2% (95% CI: 57.0-90.8) and 18.7 months, respectively. The current long-term observation resulted in an mOS of 19.2 months (95% CI: 13.1-24.8) and survival rates of 33.3 and 20.8% at 2 and 3 years from treatment, respectively. The adverse event was cerebral edema, and 21 of the 27 patients received bevacizumab treatment after decision of disease progression (PD) on imaging. CONCLUSION AB-BNCT showed an acceptable safety and survival benefit in relapsed MG, predominantly GB. Following BNCT treatment, the tumor may have shown a contrast enhancement in the irradiated field, with associated brain edema. BNCT showed a survival benefit in patients with recurrent malignant gliomas, even in the long term.

TCAF2 drives glioma cellular migratory/invasion properties through STAT3 signaling

Glioma is an intracranial tumor characterized by high mortality and recurrence rates. In the present study, the association of TRPM8 channel-associated factor 2 (TCAF2) in glioma was investigated using bioinformatics, showing significant relationships with age, WHO grade, IDH, and 1p/19q status, as well as being an independent predictor of prognosis. Immunohistochemistry of a glioma sample microarray showed markedly increased TCAF2 expression in glioblastoma relative to lower-grade glioma, with elevated expression predominating in the tumor center. Raised TCAF2 levels promote glioma cell migratory/invasion properties through the epithelial-to-mesenchymal transition-like (EMT-like) process, shown by Transwell and scratch assays and western blotting. It was further found that the effects of TCAF2 were mediated by the activation of STAT3. These results suggest that TCAF2 promotes glioma cell migration and invasion, rendering it a potential drug target in glioma therapy.

Modelling microtube driven invasion of glioma

Malignant gliomas are notoriously invasive, a major impediment against their successful treatment. This invasive growth has motivated the use of predictive partial differential equation models, formulated at varying levels of detail, and including (i) “proliferation-infiltration” models, (ii) “go-or-grow” models, and (iii) anisotropic diffusion models. Often, these models use macroscopic observations of a diffuse tumour interface to motivate a phenomenological description of invasion, rather than performing a detailed and mechanistic modelling of glioma cell invasion processes. Here we close this gap. Based on experiments that support an important role played by long cellular protrusions, termed tumour microtubes, we formulate a new model for microtube-driven glioma invasion. In particular, we model a population of tumour cells that extend tissue-infiltrating microtubes. Mitosis leads to new nuclei that migrate along the microtubes and settle elsewhere. A combination of steady state analysis and numerical simulation is employed to show that the model can predict an expanding tumour, with travelling wave solutions led by microtube dynamics. A sequence of scaling arguments allows us reduce the detailed model into simpler formulations, including models falling into each of the general classes (i), (ii), and (iii) above. This analysis allows us to clearly identify the assumptions under which these various models can be a posteriori justified in the context of microtube-driven glioma invasion. Numerical simulations are used to compare the various model classes and we discuss their advantages and disadvantages.

METTL3-mediated HOTAIRM1 promotes vasculogenic mimicry icontributionsn glioma via regulating IGFBP2 expression

BackgroundHOTAIRM1 is revealed to facilitate the malignant progression of glioma. Vasculogenic mimicry (VM) is critically involved in glioma progression. Nevertheless, the molecular mechanism of HOTAIRM1 in regulating glioma VM formation remains elusive. Thus, we attempted to clarify the role and mechanism of HOTAIRM1 in VM formation in glioma.MethodsqRT-PCR and western blot assays were used to evaluate the gene and protein expression levels of HOTAIRM1 in glioma patient tissue samples and cell lines. The role of HOTAIRM1 in glioma cell progression and VM formation was explored using a series of function gain-and-loss experiments. RNA-binding protein immunoprecipitation (RIP), RNA pull-down, and mechanism experiments were conducted to assess the interaction between HOTAIRM1/METTL3/IGFBP2 axis. Furthermore, rescue assays were conducted to explore the regulatory function of HOTAIRM1/METTL3/IGFBP2 in glioma cell cellular processes and VM formation.ResultsWe found that HOTAIRM1 presented up-regulation in glioma tissues and cells and overexpression of HOTAIRM1 facilitated glioma cell proliferation, migration, invasion, and VM formation. Furthermore, overexpression of HOTAIRM1 promoted glioma tumor growth and VM formation capacity in tumor xenograft mouse model. Moreover, HOTAIRM1 was demonstrated to interact with IGFBP2 and positively regulated IGFBP2 expression. IGFBP2 was found to promote glioma cell malignancy and VM formation. Mechanistically, METTL3 was highly expressed in glioma tissues and cells and was bound with HOTAIRM1 which stabilized HOTAIRM1 expression. Rescue assays demonstrated that METTL3 silencing counteracted the impact of HOTAIRM1 on glioma cell malignancy and VM formation capacity.ConclusionHOTAIRM1, post-transcriptionally stabilized by METTL3, promotes VM formation in glioma via up-regulating IGFBP2 expression, which provides a new direction for glioma therapy.Graphical

Knockdown of SLC39A14 inhibits glioma progression by promoting erastin-induced ferroptosis SLC39A14 knockdown inhibits glioma progression

BackgroundFerroptosis is a newly classified form of regulated cell death with implications in various tumor progression pathways. However, the roles and mechanisms of ferroptosis-related genes in glioma remain unclear.MethodsBioinformatics analysis was employed to identify differentially expressed ferroptosis-related genes in glioma. The expression levels of hub genes were assessed using real-time reverse transcriptase-polymerase chain reaction (RT-qPCR). To explore the role of SLC39A14 in glioma, a series of in vitro assays were conducted, including cell counting kit-8 (CCK-8), 5-ethynyl-2’-deoxyuridine (EdU), flow cytometry, wound healing, and Transwell assays. Enzyme-linked immunosorbent assay (ELISA) was utilized to measure the levels of indicators associated with ferroptosis. Hematoxylin-eosin (HE) and immunohistochemistry (IHC) staining were performed to illustrate the clinicopathological features of the mouse transplantation tumor model. Additionally, Western blot analysis was used to assess the expression of the cGMP-PKG pathway-related proteins.ResultsSeven ferroptosis-related hub genes, namely SLC39A14, WWTR1, STEAP3, NOTCH2, IREB2, HIF1A, and FANCD2, were identified, all of which were highly expressed in glioma. Knockdown of SLC39A14 inhibited glioma cell proliferation, migration, and invasion, while promoting apoptosis. Moreover, SLC39A14 knockdown also facilitated erastin-induced ferroptosis, leading to the suppression of mouse transplantation tumor growth. Mechanistically, SLC39A14 knockdown inhibited the cGMP-PKG signaling pathway activation.ConclusionSilencing SLC39A14 inhibits ferroptosis and tumor progression, potentially involving the regulation of the cGMP-PKG signaling pathway.

Letter to the Editor: Microsurgical anatomy of the isthmic cingulum: a new white matter crossroad and neurosurgical implications in the posteromedial interhemispheric approaches and the glioma invasion patterns

Letter to the Editor: Microsurgical anatomy of the isthmic cingulum: a new white matter crossroad and neurosurgical implications in the posteromedial interhemispheric approaches and the glioma invasion patterns

Retracted] miR‑216b inhibits glioma cell migration and invasion through suppression of FoxM1.

Following the publication of the above article, a concerned reader reported that certain of the cell invasion assay data shown in Fig. 2D, and the mouse images shown in Fig. 6A, were strikingly similar to data that appeared in the following (subsequently published) article: Li C, Zheng H, Hou W, BaoH, Xiong J, Che W, Gu Y, Sun H and Liang P: Long non-coding RNA linc00645 promotes TGF-β-induced epithelial-mesenchymal transition by regulating miR-205-3p-ZEB1 axis in glioma. Cell Death Dis 10: 717, 2019. The authors regret that the data in question featured in the original Oncology Reports article had been re-used, and accept the Editor's decision to retract this article; furthermore, the authors and the Editor apologize to the readership of the Journal for any inconvenience caused. [Oncology Reports 38: 1751‑1759, 2017; DOI: 10.3892/or.2017.5824].

STEM-21. DETERMINATION OF RACIAL DISPARITIES IN GLIOMA THROUGH RAP1B/NOTCH -INDUCED TUMORIGENESIS AND STEMNESS

Abstract BACKGROUND The incidence of GBM and survival rates after diagnosis vary significantly by race, with Caucasian Americans (CAs) having higher incidence and lower survival rates than African Americans (AAs). Accumulating evidence suggests that the failure of current therapies is partly attributed to the presence of glioma stem cells (GSC), leading to tumor progression and recurrence. Our recent work demonstrates that Ras-associated protein 1 (Rap1), a Ras-like small GTP-binding protein superfamily member, has roles in glioma cell proliferation and invasion. METHODS 1) The TCGA database was analyzed to investigate the predictive role of Rap1b in glioma patients. 2) The immunohistochemical staining for Rap1b1 was performed using the rabbit polyclonal anti-Rap1b in glioma tissue microarrays (TMA) from 76 glioma patients with 10 normal individuals. The staining intensity of cells in TMA was evaluated in three different bright fields (≥100 cells/field). The semi-quantitative HSCORE was calculated for Rap1b. 3) The mechanism of the oncogenic role of Rap1b in glioma was examined using in vitro cell culture. RESULTS 1. TCGA data showed that Rap1b mRNA is highly expressed in GBM patients compared to normal controls, indicating that Rap1b is a potential oncotarget in GBM. Expression of Rap1b is associated with worse survival in glioma patients, especially in CAs, but not in AAs. 2. The TMA data showed that elevated Rap1b protein expression correlates with grades in glioma patients. 3. In vitro studies showed that GSCs exhibit high levels of Rap1b, silencing Rap1b decreases glioma cell growth and invasion through G1/S arrest and the induction of apoptosis, as well as reduces Notch1 signaling in glioma cells; while potentiates GBM cell response to TMZ. CONCLUSION This study provided new knowledge of Rap1b’s potential as a therapeutic drug target for GBM therapy and revealed biological diversity across races and unaddressed health disparities.

CNSC-10. GLIOBLASTOMA CELLS IMITATE NEURON’S EXCITABILITY IN ACUTE AND ORGANOTYPIC HUMAN BRAIN SLICES

Abstract Glioblastoma (GBM) is a highly lethal cancer due to its inter- and intra-patient molecular and physiological heterogeneity, and its complex interaction with brain tissue. Recent findings demonstrate that Neuron-to-brain tumor-synaptic-communications (NBTSCs) engage in a vicious cycle of enhanced neuronal activity, driving glioma progression and invasion and tumor-induced epilepsy. However, the physiology of these synaptic interactions in the tumor-infiltrated human neocortex remains largely uncharacterized. To address this gap, our study focused on investigating the intrinsic electrical properties of glioma cells and NBTSCs in the tumor-infiltrated human cortex using a unique experimental workflow involving acute and cultured human tumor-infiltrated brain slices. Via an adeno-associated virus-assisted gene delivery technique, we selectively express fluorescence proteins in a cell-type specific manner. By performing fluorescence-guided whole-cell patch clamp recording, we characterized the electrophysiological properties of glioma cells and neurons under the tumor microenvironment. We observed that glioma cells from tumor-infiltrated human brain samples displayed depolarized resting membrane potential (-32.21 ± 2.1mV) and high input resistance (1.24 ± 0.18 GΩ). Approximately 69.2% of glioma cells exhibited spikelets or distorted-action potentials upon current injection. Consistent with other studies, a subset of glioma cells (11.8%) exhibited spontaneous excitatory postsynaptic currents (sEPSC). In addition, the tumor-infiltrated microenvironment significantly influences the proximal neurons’ physiology and the neuronal microcircuitry, leading to abnormal intrinsic electrical properties, depolarized resting membrane potential (-37.66 ± 4.32 mV), and a significant reduction in spontaneous synaptic input frequency. Collectively, our study consolidates the existence of NBTSCs in human cancer patients and reveals that glioma cells exhibit neuron-like excitability, which is contrary to the common understanding that they are considered as non-excitable. Under the tumor microenvironment, neurons display hyperexcitability. Our newly established organotypic human brain slice culture platform provides potential grounds for exploring further the biological characteristics of gliomas and NBTSCs.

PATH-60. BRAIN TUMORS: FROM ONCOSTREAMS TO LIQUID CRYSTALS

Abstract High grade gliomas (HGG) are the most common, destructive, and varied of all malignant brain tumors. HGG are heterogeneous at the histological, cellular, and molecular level, which makes them hard to study and treat. One particular tumor pathological differentiation is mesenchymal differentiation, containing oblong, motile cells. We recently noted distinct fascicles of elongated, aligned, mesenchymal-like cells in mouse and human gliomas, which we denote as oncostreams. Time-lapse confocal microscopy in ex vivo slices, and in in vivo two photon imaging, indicated that cells in oncostreams are motile. Oncostream motility was classified based on cellular orientation. The molecular characteristics of oncostreams were determined by laser capture microdissection, RNA-sequencing, and bioinformatics. 43 genes were differentially expressed; COL1A1 was overexpressed in oncostreams. Inhibition of COL1A1 in mouse gliomas, using the Sleeping Beauty transposon model, reduced oncostreams, tumor aggressiveness, proliferation, tumor vasculature, and collective glioma invasion. More recently, we elucidated that glioma cell growth in vitro, and potentially in vivo displays domains of nematic orientation (oncostreams) and topological defects, suggesting that gliomas are organized as liquid crystals. Topological defects are singularities of local orientation, and characteristic of liquid crystals. Further, studies of gliomas in vivo, suggest the presence of ±1/2 topological defects. Thus, nematic orientation and topological defects are present in brain tumors in vitro and in vivo. This provides support for our hypothesis that brain tumors are organized as active liquid crystals. As topological defects have been exploited to alter liquid crystal behavior, we hypothesize that manipulating brain tumor liquid crystalline behavior will be of therapeutic importance. Comba et al. (2022) Spatiotemporal analysis of glioma heterogeneity reveals COL1A1 as an actionable target to disrupt tumor progression. Nature Communications: Wood et al. (2023) Scale-free correlations and potential criticality in weakly ordered populations of brain cancer cells. Science Advances (in press).

CNSC-23. ROLE OF GLIAL PH-DEPENDENT METABOLIC REGULATION IN GLIOMA PROGRESSION

Abstract Malignant glioma is a devastating brain cancer with barely any improvement in prognosis over decades. One key mechanism for glioma invasiveness is the dynamic metabolic communication between glioma and surrounding cells shaping the tumor microenvironment. While extracellular acidosis is a pathological hallmark of glioma, pH-dependent mechanisms underlying tumor metabolic reprogramming remain poorly defined. Our study focuses on a glial-enriched sodium-bicarbonate cotransporter, Slc4a4, which was previously identified as intracellular and extracellular pH regulator. While Slc4a4-mediated pH regulation is important for physiological brain function and responses after injury, its role in glioma progression is largely undefined. To begin addressing this question, we analyzed The Cancer Genome Atlas (TCGA) database, finding high Slc4a4 expression correlates with prolonged survival in glioma patients. Corroboratively, Slc4a4 gain-of-function (GOF) drastically decreases tumorigenesis and angiogenesis in patient-derived-xenograft and CRISPR-mediated de novo mouse glioma models. These results are further complemented by loss-of-function (LOF) studies using glial-specific Slc4a4 knockout mice, suggesting an inhibitory role of Slc4a4 in glioma growth and associated angiogenesis. A combination of unbiased metabolomic and cancer-targeted proteomic profiling of Slc4a4 GOF/LOF mouse glioma reveals an inverse correlation between Slc4a4 and a key lipid metabolism protein, FABP5 (Fatty Acid Binding Protein 5), which is coupled with dysregulated lipid metabolism. Moreover, analysis of TCGA database shows inverse expression and survival correlation of Slc4a4 and FABP5 in glioma patients. Further functional study shows that overexpression of FABP5 reverses Slc4a4’s inhibitory effects on glioma growth in immunocompetent mouse glioma model, supporting a functional antagonism between Slc4a4 and FABP5. Together, our study indicates that Slc4a4 plays a protective role in glioma progression by regulating metabolic activities, providing critical insights into pH-dependent metabolic reprogramming in glioma.

MODL-35. BIOENGINEERED HYDROGEL AND BLOOD BRAIN BARRIER-ON-A-CHIP SYSTEM TO STUDY GLIAL CELL ACTIVATION AND BLOOD BRAIN BARRIER DYSFUNCTION IN GLIOBLASTOMA

Abstract Treatments for glioblastoma (GBM) are limited leading to short patient life expectancies after diagnosis. Current preclinical models of GBM fail to accurately replicate the function of the blood brain barrier (BBB) and the extreme heterogeneity of the GBM tumor hindering the drug development process. Therefore, there is a pressing need for improved model systems to study how different GBM subpopulations interact with glial cells and the BBB. To build such a model, we first focused on designing a 3D extracellular matrix-based hydrogel biomaterial that would support human astrocytes and a functional BBB. The hydrogel chosen for these studies is composed of functionalized hyaluronic acid (HA) and gelatin and has similar mechanical properties to the human brain. Using confocal imaging and qPCR, we have shown that astrocytes encapsulated in this hydrogel have greater branching and express fewer markers of activation compared to astrocytes grown in commonly used 3D biomaterials such as collagen I and Matrigel. Treatment with inflammatory cytokines and GBM cell derived extracellular vesicles (EVs) revealed that astrocytes in this environment display the activation and inflammatory phenotypes observed in vivo in GBM. Next, this hydrogel biomaterial was deployed in a bioengineered BBB-on-a-chip. We have shown that this system supports the formation of 3D microvessel structures with human brain endothelial cells, pericytes, and astrocytes that accurately mimic the function of the human BBB. Studies using this BBB-on-a-chip have shown that invasive glioma stem cells alter BBB permeability influencing the transport of certain therapeutics to the tumor site. We are now beginning to test how various subpopulations of GBM tumor cells behave in this model and how changes to glial cells and the BBB impact drug delivery and efficacy. This study shows that engineered in vitro models can provide critical insight into disease mechanisms and inform treatment design in GBM.

Combining organotypic tissue culture with light-sheet microscopy (OTCxLSFM) to study glioma invasion.

Glioblastoma is a very aggressive tumor and represents the most common primary brain malignancy. Key characteristics include its high resistance against conventional treatments, such as radio- and chemotherapy and its diffuse tissue infiltration, preventing complete surgical resection. The analysis of migration and invasion processes in a physiological microenvironment allows for enhanced understanding of these phenomena and can lead to improved therapeutic approaches. Here, we combine two state-of-the-art techniques, adult organotypic brain tissue slice culture (OTC) and light-sheet fluorescence microscopy (LSFM) of cleared tissues in a combined method termed OTCxLSFM. Using this methodology, we can show that glioblastoma tissue infiltration can be effectively blocked through treatment with arsenic trioxide or WP1066, as well as genetic depletion of the tetraspanin, transmembrane receptor CD9, or signal transducer and activator of transcription 3 (STAT3). With our analysis pipeline, we gain single-cell level, three-dimensional information, as well as insights into the morphological appearance of the tumor cells.

SUMOylation of RALY promotes vasculogenic mimicry in glioma cells via the FOXD1/DKK1 pathway

Human malignant gliomas are the most common and aggressive primary malignant tumors of the human central nervous system. Vasculogenic mimicry (VM), which refers to the formation of a tumor blood supply system independently of endothelial cells, contributes to the malignant progression of glioma. Therefore, VM is considered a potential target for glioma therapy. Accumulated evidence indicates that alterations in SUMOylation, a reversible post-translational modification, are involved in tumorigenesis and progression. In the present study, we found that UBA2 and RALY were upregulated in glioma tissues and cell lines. Downregulation of UBA2 and RALY inhibited the migration, invasion, and VM of glioma cells. RALY can be SUMOylated by conjugation with SUMO1, which is facilitated by the overexpression of UBA2. The SUMOylation of RALY increases its stability, which in turn increases its expression as well as its promoting effect on FOXD1 mRNA. The overexpression of FOXD1 promotes DKK1 transcription by activating its promoter, thereby promoting glioma cell migration, invasion, and VM. Remarkably, the combined knockdown of UBA2, RALY, and FOXD1 resulted in the smallest tumor volumes and the longest survivals of nude mice in vivo. UBA2/RALY/FOXD1/DKK1 axis may play crucial roles in regulating VM in glioma, which may contribute to the development of potential strategies for the treatment of gliomas.

CircIQGAP1 regulates RCAN1 and RCAN2 through the mechanism of ceRNA and promotes the growth of malignant glioma

Circular RNA (circRNA) is one of non-coding RNA with specific circular structure, which has been found to be involved in regulating a series of malignant biological behaviors in many malignant tumors. In this study, based on the IDH1 molecular typing of gliomas, we identified a significant downregulation of circRNA (circIQGAP1) expression in IDH1 mutant gliomas by high-throughput sequencing. In 79 tissue samples, we confirmed that circIQGAP1 expression was significantly downregulated in IDH1 mutant gliomas, and that low circIQGAP1 expression was positively associated with better prognosis. Knockdown of circIQGAP1 in glioma cell lines inhibited glioma cell malignancy and conversely overexpression of circIQGAP1 promoted glioma malignancy. circIQGAP1 regulated glioma cell migration, proliferation, invasion and apoptosis through miR-1256/RCAN1/Bax/Bcl-2/Caspase3 and miR-622/RCAN2/Bax/Bcl-2/Caspase3 axes. These results suggest that circIQGAP1 plays an important role in glioma development, promotes tumor growth, and is a potential therapeutic target for glioma.

Chemokine receptor CXCR4 interacts with nuclear receptor Nur77 and promote glioma invasion and progression

BackgroundGlioma is the most common primary brain tumor. It is prone to progress and have high rate of mortality regardless of radiation or chemotherapy due to its invasive growth features. Chemokine and its receptor CXCL12 and CXCR4 play important roles in cancer metastasis. MethodsIn this study, we investigate the role of CXCR4 in the progression of glioma by various molecular technologies, including qRT-PCR, Western blotting, wound closure assay, transwell assay et al. ResultsIt was found that CXCR4 was overexpressed in glioma tissues. The expression of CXCR4 was correlated with patients’ overall survival. Wound closure assay and transwell invasion assay showed that inhibition of CXCR4 significantly reduced the expression of biomarkers related to the formation of invadopodium, leading to decrease the invasion and migration of glioma tumor cells. Knocking down the nuclear receptor Nur77 remarkably decreased CXCR4 expression and reduced glioma cell invasion and migration. The reduction of glioma cell invasion and migration were observed after Nur77 inhibitor treatment. ConclusionTaken together, these results indicated that CXCR4 is critical in promoting glioma migration and invasion. Inhibition of Nur77 reduces CXCR4 related cancer progression.