Inhibited Glioma Cell Invasion Research Articles

TGIF2 is a potential biomarker for diagnosis and prognosis of glioma.

TGFB-induced factor homeobox 2 (TGIF2), a member of the Three-Amino-acid-Loop-Extension (TALE) superfamily, has been implicated in various malignant tumors. However, its prognostic significance in glioma, impact on tumor immune infiltration, and underlying mechanisms in glioma development remain elusive. The expression of TGIF2 in various human normal tissues, normal brain tissues, and gliomas was investigated using HPA, TCGA, GTEx, and GEO databases. The study employed several approaches, including Kaplan-Meier analysis, ROC analysis, logistic regression, Cox regression, GO analysis, KEGG analysis, and GSEA, to explore the relationship between TGIF2 expression and clinicopathologic features, prognostic value, and potential biological functions in glioma patients. The impact of TGIF2 on tumor immune infiltration was assessed through Estimate, ssGSEA, and Spearman analysis. Genes coexpressed with TGIF2 were identified, and the protein-protein interaction (PPI) network of these coexpressed genes were constructed using the STRING database and Cytoscape software. Hub genes were identified using CytoHubba plugin, and their clinical predictive value was explored. Furthermore, in vitro experiments were performed by knocking down and knocking out TGIF2 using siRNA and CRISPR/Cas9 gene editing, and the role of TGIF2 in glioma cell invasion and migration was analyzed using transwell assay, scratch wound-healing assay, RT-qPCR, and Western blot. TGIF2 mRNA was found to be upregulated in 21 cancers, including glioma. High expression of TGIF2 was associated with malignant phenotypes and poor prognosis in glioma patients, indicating its potential as an independent prognostic factor. Furthermore, elevated TGIF2 expression positively correlated with cell cycle regulation, DNA synthesis and repair, extracellular matrix (ECM) components, immune response, and several signaling pathways that promote tumor progression. TGIF2 showed correlations with Th2 cells, macrophages, and various immunoregulatory genes. The hub genes coexpressed with TGIF2 demonstrated significant predictive value. Additionally, in vitro experiments revealed that knockdown and knockout of TGIF2 inhibited glioma cell invasion, migration and suppressed the epithelial-mesenchymal transition (EMT) phenotype. TGIF2 emerges as a potential biomarker for glioma, possibly linked to tumor immune infiltration and EMT.

The Chemokine Receptor CCR1 Mediates Microglia Stimulated Glioma Invasion

Glioblastoma multiforme (GBM) is the most aggressive form of adult brain tumor which is highly resistant to conventional treatment and therapy. Glioma cells are highly motile resulting in infiltrative tumors with poorly defined borders. Another hallmark of GBM is a high degree of tumor macrophage/microglia infiltration. The level of these tumor-associated macrophages/microglia (TAMs) correlates with higher malignancy and poorer prognosis. We previously demonstrated that inhibition of TAM infiltration into glioma tumors with the CSF-1R antagonist pexidartinib (PLX3397) can inhibit glioma cell invasion in-vitro and in-vivo. In this study, we demonstrate an important role for the chemokine receptor CCR1 in mediating microglia/TAM stimulated glioma invasion. Using two structurally distinct CCR1 antagonists, including a novel inhibitor "MG-1-5", we were able to block microglial activated GL261 glioma cell invasion in a dose dependent manner. Interestingly, treatment of a murine microglia cell line with glioma conditioned media resulted in a strong induction of CCR1 gene and protein expression. This induction was attenuated by inhibition of CSF-1R. In addition, glioma conditioned media treatment of microglia resulted in a rapid upregulation of gene expression of several CCR1 ligands including CCL3, CCL5, CCL6 and CCL9. These data support the existence of tumor stimulated autocrine loop within TAMs which ultimately mediates tumor cell invasion.

EDEM2 is a diagnostic and prognostic biomarker and associated with immune infiltration in glioma: A comprehensive analysis.

Glioma is a highly common pathological brain tumor. Misfolded protein response, which is strongly associated with the growth of cancerous tumors, is mediated by the gene, endoplasmic reticulum degradation-enhancing alpha-mannosidase-like protein 2. However, this gene has not been linked to glioma. To assess the same, we used The Cancer Genome Atlas, Chinese Glioma Genome Atlas, and Genotype-Tissue Expression datasets. The gene was overexpressed in gliomas. This overexpression was linked to unfavorable clinical characteristics, such as the World Health Organization grade, isocitrate dehydrogenase mutation, and the combined loss of the short arm chromosome 1 and the long arm of chromosome 19. Quantitative polymerase chain reaction experiments and immunohistochemistry on clinical samples from our institution verified the gene's expression and clinical importance. The Human Protein Atlas website verified the messenger ribonucleic acid expression of the gene in glioma cell lines, and immunohistochemistry verified the presence of its protein. A previous survival study indicated that its high expression is substantially related to a bad prognosis. It was identified as an independent predictor of primary glioma prognosis using multivariate Cox regression analysis. To forecast individual survival, we created a nomogram based on this (concordance-index = 0.847). Additionally, functional annotation demonstrated its major role in the control of the extracellular matrix and immune system. The scratch assay and transwell migration assay confirmed the decreased invasive ability of U251 glioma cells with the gene knockdown. Its increased expression was found to be related to the extent of macrophage infiltration using the CIBERSORT, ESTIMATE, Single-sample Gene Set Enrichment Analysis, and Tumor Immune Single-Cell Hub (TISCH) algorithms. The Tumor Immune Dysfunction and Exclusion algorithm revealed that the gene can accurately predict the response of immunotherapy (area under the receiver operating characteristic curve = 0.857). Further, isocitrate dehydrogenase 1 mutation is typically more frequent when the gene expression is high. Finally, five medicines targeting this gene were discovered utilizing the molecular docking program and drug sensitivity analysis of the RNAactDrug website. Low expression of the gene inhibited glioma cell invasion. Therefore, the gene is helpful for the diagnosis, prognosis, and case-specific immunotherapy of glioma.

The nuclear transporter importin-11 regulates the Wnt/β-catenin pathway and acts as a tumor promoter in glioma

Karyopherins mediate the macromolecular transport between the cytoplasm and the nucleus and participate in cancer progression. However, the role and mechanism of importin-11 (IPO11), a member of the karyopherin family, in glioma progression remain undefined. Effects of IPO11 on glioma progression were detected using CCK-8, colony formation assay, flow cytometry analysis, caspase-3 activity assay, and Transwell invasion assay. Western blot analysis was used to detect the expression of active caspase-3, active caspase-7, active caspase-9, N-cadherin, Vimentin, E-cadherin, β-catenin, and c-Myc. The activity of Wnt/β-catenin pathway was evaluated by the T-cell factor/lymphoid enhancer factor (TCF/LEF) transcription factor reporter assay. Results showed that IPO11 knockdown inhibited proliferation and reduced colony number in glioma cells. IPO11 silencing promoted the apoptotic rate, increased expression levels of active caspase-3, caspase-7, and caspase-9, and enhanced caspase-3 activity. Moreover, IPO11 silencing inhibited glioma cell invasion by suppressing epithelial-to-mesenchymal transition (EMT). Mechanistically, IPO11 knockdown inactivated the Wnt/β-catenin pathway. β-Catenin overexpression abolished the effects of IPO11 silencing on the proliferation, apoptosis, and invasion in glioma cells. Furthermore, IPO11 silencing blocked the malignant phenotypes and repressed the Wnt/β-catenin pathway in vivo. In conclusion, IPO11 knockdown suppressed the malignant phenotypes of glioma cells by inactivating the Wnt/β-catenin pathway.

Knockdown of DCLK1 Inhibits Proliferation, Migration and Invasion of Glioma Cells

Knockdown of DCLK1 Inhibits Proliferation, Migration and Invasion of Glioma Cells

Arg kinase mediates CXCL12/CXCR4-induced invadopodia formation and invasion of glioma cells

Compared with noninvasive tumor cells, glioma cells overexpress chemokine receptor type 4 (CXCR4), which exhibits significantly greater expression in invasive tumor cells than in noninvasive tumor cells. C-X-C motif chemokine ligand 12 (CXCL12, also known as stromal derived factor-1, SDF-1) and its cell surface receptor CXCR4 activate a signaling axis that induces the expression of membrane type-2 matrix metalloproteinase (MT2-MMP), which plays a pivotal role in the invasion and migration of various cancer cells; however, the specific mechanism involved in this is unclear. Recently, studies have shown that invadopodia can recruit and secrete related enzymes, such as matrix metalloproteinases (MMPs), to degrade the surrounding extracellular matrix (ECM), promoting the invasion and migration of tumor cells. Phosphorylated cortactin (pY421-cortactin) is required for the formation and maturation of invadopodia, but the upstream regulatory factors and kinases involved in phosphorylation have not been elucidated. In this study, we found that CXCL12/CXCR4 was capable of inducing glioma cell invadopodia formation, probably by regulating cortactin phosphorylation. The interaction of cortactin and Arg (also known as Abl-related nonreceptor tyrosine kinase, ABL2) in glioma cells was demonstrated. The silencing of Arg inhibited glioma cell invadopodia formation and invasion by blocking cortactin phosphorylation. Moreover, CXCL12 could not induce glioma cell invasion in Arg-knockdown glioma cells. Based on these results, it can be concluded that Arg mediates CXCL12/CXCR4-induced glioma cell invasion, and CXCL12/CXCR4 regulates invadopodia maturation through the Arg-cortactin pathway, which indicates that Arg could be a candidate therapeutic target to inhibit glioma cell invasion.

Sevoflurane downregulates insulin-like growth factor-1 to inhibit cell proliferation, invasion and trigger apoptosis in glioma through the PI3K/AKT signaling pathway.

Sevoflurane is a new type of inhalation anesthetic used widely in the clinic. It has the characteristics of rapid induction, rapid recovery, and less irritative to the airway. Studies have shown that sevoflurane can affect the invasion and migration of a variety of malignant tumors. However, its effects on human glioma cells and related mechanisms are not clear. Cultured U251 and U87 cells were pretreated with sevoflurane. The effect of sevoflurane on proliferation was evaluated by MTT, and cell migration assay, cell apoptosis, and invasion ability were evaluated by wound-healing assay, cell apoptosis, and Transwell assays. Insulin-like growth factor-1 (IGF-1) and PI3K/AKT signaling pathway gene expression in sevoflurane-treated cell lines was measured by western blotting analysis, respectively. 5% sevoflurane significantly inhibited proliferation ability in both U251 and U87 cells. Sevoflurane inhibited glioma cells invasion and migration, and promoted apoptosis. Sevoflurane inhibited IGF-1 and promoted the expression of apoptosis-related proteins in glioma cells. In addition, sevoflurane inhibited the PI3K/AKT signaling pathway in glioma cells. This study clarifies that sevoflurane inhibits proliferation, invasion, and migration, and promotes apoptosis in glioma cells. These effects are regulated by IGF-1, an upstream gene of the PI3K/AKT signaling pathway. These findings may be significant for the selection of anesthetic agents in glioma surgery to improve the prognosis of patients.

EMP1 regulates cell proliferation, migration, and stemness in gliomas through PI3K-AKT signaling and CD44.

Glioblastoma multiforme (GBM) is an intracranial tumor; the feature is higher malignant and poorer prognosis. The search for therapeutic targets for gliomas has always been a focus of research in the field of neurology. The unusual expression of epithelial membrane protein 1 (EMP1) has been proved in most tumors. In our study, we determined the expression level of EMP1 expression in glioma tissues. There were higher levels of EMP1 in glioma tissues-particularly GBM tissues-than those in normal brain tissues. Then we discovered that silencing EMP1 inhibited glioma cell invasion and proliferation through inhibiting the PI3K-AKT signaling pathway. Subsequently, we investigated the function of EMP1 on glioma stem cells and found that it regulates the expression of CD44 in such cells to promote stemness. Taken together, the new strategies for the treatment of glioma may be provided by these finding, thereby improving the prognosis associated with it.

MiR-4725-3p targeting stromal interacting molecule 1 signaling is involved in xanthohumol inhibition of glioma cell invasion.

Glioblastoma multiforme is the most common brain tumor in adults. Because of its highly invasive nature, it is not easy to treat, resulting in high mortality rates. Stromal interacting molecule 1 (Stim1) plays important roles in regulating store-operated Ca2+ entry, and controls invasion by cancer cells. However, the mechanisms and functions of Stim1 in glioma progression are still unclear. In this study, we investigated the effects of targeting Stim1 expression on glioma cell invasion. By analyzing profiles of glioblastoma multiforme patients from RNA-sequencing data in The Cancer Genome Atlas, higher expression levels of STIM1 were correlated with the poor survival. Furthermore, signaling pathways associated with tumor malignancy, including the epithelial-to-mesenchymal transition (EMT), were activated in patients with high STIM1 expression according to gene set enrichment analyses. Higher Stim1 levels were found in glioma cells compared to human astrocytes, and these higher levels enhanced glioma cell invasion. Xanthohumol (XN), a prenylated flavonoid extracted from the hop plant Humulus lupulus L. (Cannabaceae), significantly reduced cell invasion through inhibiting Stim1 expression. From an micro(mi)RNA array analysis, miR-4725-3p was up-regulated by XN treatment. Over-expression of miR-4725-3p inhibited glioma cell invasion via directly targeting the 3'-untranslated region of STIM1. The extracellular signal-regulated kinase/c-Fos pathway was also validated to participate in XN-up-regulated miR-4725-3p expression according to promoter and chromatin immunoprecipitation assays. These results emphasize that miR-4725-3p-inhibited STIM1 signaling is involved in XN-attenuated glioma cell invasion. These findings may provide insights into novel therapeutic strategies for future glioblastoma therapy and drug development. Open Data: Materials are available on https://cos.io/our-services/open-science-badges/ https://osf.io/93n6m/.

The effect of celecoxib on the biological characteristics of glioma cells

Objective To investigate the effect of celecoxib on glioma cell proliferation, apoptosis, migration and invasion ability. Methods Methyl thiazol tetrazolium (MTT) assay was used to detect glial tumor cell proliferation of U251, T98G, U87 after treatment with 0, 20, 40 or 60 μmol/L celecoxib for 24, 48, 72 or 96 h. Flow cytometry was used to detect cell apoptosis after treatment with 40 μmol/L celecoxib for 48 h. Cell scratch test was used to detect cell migration after treatment with 40 μmol/L celecoxib for 48 h. Transwell was used to detect cell invasion after treatment with 40 μmol/L celecoxib for 48 h. The expression levels of cyclooxygenase-2 (COX-2), B cell lymphoma/leukemia-2 (bcl-2), B cell lymphoma/leukemia-2 associated X protein (bax), matrix metalloproteinase (MMP)-9, MMP-2 in cells was detected by Western blotting. Results Celecoxib can inhibit the proliferation of glioma cells and there is no obvious inhibitory effect on normal astrocytoma. The inhibitory effect of Celecoxib on glioma cell proliferation was depended on the reaction time and drug concentration. The apoptosis rate of glioma cell after 40μmol/L celecoxib was higher than the control group, and the difference was significant [(3.17±0.16)% vs. (16.08±1.57)%, (3.17±0.16)% vs. (16.08±1.57)%, t=14.169, P=0.000]. The migration rate of glioma cell after treatment with 40 μmol/L celecoxib was lower than the control group, the difference was significant . The invasion ability of glioma cell after 40 μmol/L celecoxib was lower than the control group, the difference was significant [(100.00±5.26)% vs. (41.28±5.84)%, t=12.940, P=0.000]. Glioma cells after celecoxib treatment in COX-2, bcl-2, MMP-9, MMP-2 was significantly decreased than control group [(229.5±11.36) vs. (97.32±7.95), t=16.512, P=0.000]. The bax protein of Glioma cells after celecoxib treatmentwas significantly higher than control group (t1=19.696, P1=0.000; t2=17.774, P2=0.000; t3=12.970, P3=0.000; t4=10.569, P4=0.001). Conclusion Celecoxib can inhibit glioma cell proliferation, migration and invasion ability, and promote the apoptosis of glioma cells, the mechanism of which was related to COX-2, bcl-2, bax, MMP-9, MMP-2. Key words: Glioma; Proliferation; Apoptosis; Invasion; Celecoxib

Inhibition of glioblastoma cell invasion by hsa-miR-145-5p and hsa-miR-31-5p co-overexpression in human mesenchymal stem cells.

Human bone marrow–derived mesenchymal stem cells (hMSCs) show tropism for brain tumors and may be a useful vehicle for drug or gene delivery to malignant gliomas. Recently, some microRNAs (miRNAs) have been shown to suppress the invasiveness of malignant gliomas. To test their potential to become vehicles for the delivery of miRNA to malignant gliomas, hMSCs were engineered so that hMSC secretion of miRNAs that inhibit glioma cell invasion was enabled without altering the hMSC tropism for glioma cells. In coculture, hMSCs cotransfected with hsa-miR-145-5p and -31-5p miRNAs showed markedly reduced invasion by U87 glioma cells in a contact-dependent manner both in vitro and ex vivo, with invasion of hMSCs cotransfected with these 2 miRNAs by the U87 cells reduced to 60.7% compared with control cells. According to a Matrigel invasion assay, the tropism of the hMSCs for U87 cells was not affected. In glioma cell lines U251 and LN229, hMSCs exhibited tropism in vivo, and invasion of hMSCs cotransfected with hsa-miR-145-5p and -31-5p was also significantly less than that of control cells. When U87 cells were coimplanted into the striatum of organotypic rat brain slices with hMSCs cotransfected with hsa-miR-145 and -31-5p, the relative invasive area decreased by 37.1%; interestingly, these U87 cells showed a change to a rounded morphology that was apparent at the invasion front. Whole-genome microarray analysis of the expression levels of 58,341 genes revealed that the co-overexpression of hsa-miR-145-5p and -31-5p downregulated FSCN1 expression in U87 cells. This study demonstrates that miRNA overexpression in hMSCs can alter the function of glioma cells via contact-dependent transfer. Co-overexpression of multiple miRNAs may be a useful and novel therapeutic strategy. The study results suggest that hMSCs can be applied as a delivery vehicle for miRNAs.

MiRNA-320a inhibits glioma cell invasion and migration by directly targeting aquaporin 4.

Glioma is the most aggressive and malignant type of primary intracranial tumor. In recent decades, despite the rapid development of modern surgery and therapeutic strategies available for brain tumors, the prognosis of glioma remains poor and the median survival time is <15months. In this study, we found that the levels of miRNA-320a were significantly decreased in patients with glioma, and that elevated miRNA-320a expression was associated with a better prognosis. In addition, aquaporin 4 (AQP4) was identified as a direct target of miRNA-320a. Overexpression of miRNA-320a led to the inhibition of cell invasion and migration via targeting of AQP4. Therefore, our results suggested that miRNA-320a could suppress the aggressive capacity of tumors by targeting AQP4, and that miRNA-320a could serve as a new effective therapeutic target for glioma surgical and therapeutic strategies.

MicroRNA-409-3p Represses Glioma Cell Invasion and Proliferation by Targeting High-Mobility Group Nucleosome-Binding Domain 5

Emerging evidence has suggested that aberrantly expressed microRNAs (miRNAs) are associated with glioma development and progression. The aberrant expression of miR-409-3p has been reported in several human cancers. However, little is known about the function of miR-409-3p in gliomas. The aim of this study was to investigate the specific role and molecular mechanism of miR-409-3p in gliomas. In the present study, we found that miR-409-3p was downregulated in glioma tissue and cell lines. Overexpression of miR-409-3p inhibited glioma cell invasion and proliferation, whereas suppression of miR-409-3p promoted glioma cell invasion and proliferation. High-mobility group nucleosome-binding domain 5 (HMGN5), a well-known oncogene in gliomas, was identified as a functional target of miR-409-3p using bioinformatics, dual-luciferase reporter assay, real-time quantitative polymerase chain reaction, and Western blot analysis. Furthermore, miR-409-3p was found to regulate the expression of matrix metalloproteinase 2 and cyclin D1. Restoration of HMGN5 expression significantly reversed the inhibitory effects of miR-409-3p overexpression on glioma cell invasion and proliferation. Taken together, our results suggest that miR-409-3p inhibits glioma cell invasion and proliferation by targeting HMGN5, representing a potential therapeutic target for glioma.

Nicotinic acid inhibits glioma invasion by facilitating Snail1 degradation

Malignant glioma is a formidable disease that commonly leads to death, mainly due to the invasion of tumor cells into neighboring tissues. Therefore, inhibition of tumor cell invasion may provide an effective therapy for malignant glioma. Here we report that nicotinic acid (NA), an essential vitamin, inhibits glioma cell invasion in vitro and in vivo. Treatment of the U251 glioma cells with NA in vitro results in reduced invasion, which is accompanied by a loss of mesenchymal phenotype and an increase in cell-cell adhesion. At the molecular level, transcription of the adherens junction protein E-cadherin is upregulated, leading to accumulation of E-cadherin protein at the cell-cell boundary. This can be attributed to NA’s ability to facilitate the ubiquitination and degradation of Snail1, a transcription factor that represses E-cadherin expression. Similarly, NA transiently inhibits neural crest migration in Xenopus embryos in a Snail1-dependent manner, indicating that the mechanism of action for NA in cell migration is evolutionarily conserved. We further show that NA injection blocks the infiltration of tumor cells into the adjacent brain tissues and improves animal survival in a rat model of glioma. These results suggest that NA treatment may be developed into a potential therapy for malignant glioma.

Transcriptional repression of FOXO1 by KLF4 contributes to glioma progression.

In this study, our findings indicated that FOXO1 expression frequently decreased in glioma tissues and cells. FOXO1 expression decrease correlated with glioma progression and predicted a worse overall survival of glioma patients. Restored FOXO1 expression inhibited glioma cells invasion and suppressed glioma cells proliferation in vitro and growth in vivo. Additionally, we found that KLF4 expression frequently increased in glioma tissues and negatively correlated with FOXO1 expression. Bioinformatics analysis and experimental results indicated that KLF4 transcriptionally repressed FOXO1 expression in glioma cells. Moreover, KLF4 expression increase correlated with glioma progression and predicted a poorer overall survival of glioma patients. KLF4 knockdown attenuated glioma cells invasion and growth. These data provide a rationale for targeted intervention on KLF4-FOXO1 signaling pathway to suppress glioma progression.

In Silico prediction of the molecular basis of ClTx and AaCTx interaction with matrix metalloproteinase-2 (MMP-2) to inhibit glioma cell invasion

Glioblastoma is the deadliest type of brain cancer. Treatment could target the Matrix metalloproteinase-2 (MMP-2), which is known to be involved in the invasion process of glioblastoma cells. But current available inhibitors are not selective to MMP-2 due to their interaction with the catalytic binding site, which is highly conserved in all MMPs structures. Interestingly, members of the chloride channel blocker scorpion toxins, such as chlorotoxin (ClTx) and AaCTx, inhibit glioblastoma cell invasion and show a promising therapeutic potential. Indeed, it has been shown that CITx inhibits selectively MMP-2 and was also able to cross the blood brain and tissue barriers. Although ClTx and AaCTx show high sequence similarity, AaCTx is ten times less active than ClTx. By using molecular modeling, molecular dynamics and MM-PB(GB)SA free energy estimation, we present the first computational study reporting the interaction mode of ClTx/AaCTx with MMP-2. We found that the two peptides probably act on an exosite of MMP-2 comprising mainly residues from the collagen binding domain, a feature that could be exploited to enhance the selectivity toward MMP-2. van der Waals and hydrophobic forces are the primary mediators of this interaction. The N- and C-termini of the two peptides harbor the key residues of the interaction spread across a conserved amino acid patch. In particular, F6 contributes mostly to the binding free energy in ClTx. We also suggest that the lack of the C-terminal arginine and the residues P10 and R24, might be responsible for altering the activity of AaCTx toward glioblastoma cells compared to ClTx.

MiR-101 inhibits glioma cell invasion via the downregulation of COX-2.

Glioma is the most common type of primary tumor of the central nervous system. The present study aimed to demonstrate the role of miR-101 and cyclooxygenase-2 (COX-2) in the initiation and development of glioma. The expression of miR-101 and COX-2 in normal and malignant human glial cells and tissues was determined by western blotting and quantitative polymerase chain reaction analysis. The role of miR-101 on COX-2 expression was evaluated by a dual-luciferase reporter assay. The effects of miR-101 and COX-2 in glioma cell proliferation and invasion was verified by CCK-8 test and Transwell assays, respectively. The present study demonstrated that miR-101 expression was downregulated while COX-2 was upregulated in glioma tissues and cells. Furthermore, transfection of miR-101 significantly downregulated COX-2 expression in both U373 and U87 glioma cells. In addition, further experiments revealed that overexpression of miR-101 resulted in significant inhibition of the in vitro proliferation and migration of glioma cells, and the in vivo growth of established tumors. Direct downregulation of COX-2 by transfection with corresponding small interfering RNA also inhibited the proliferation and invasion of glioma cells. These results indicate that downregulation of miR-101 is involved in the initiation and development of glioma via COX-2 upregulation.

Propentofylline inhibits glioblastoma cell invasion and survival by targeting the TROY signaling pathway.

Glioblastoma (GBM) is the most common primary tumor of the CNS and carries a dismal prognosis. The aggressive invasion of GBM cells into the surrounding normal brain makes complete resection impossible, significantly increases resistance to the standard therapy regimen, and virtually assures tumor recurrence. Median survival for newly diagnosed GBM is 14.6months and declines to 8months for patients with recurrent GBM. New therapeutic strategies that target the molecular drivers of invasion are required for improved clinical outcome. We have demonstrated that TROY (TNFRSF19), a member of the TNFR super-family, plays an important role in GBM invasion and resistance. Knockdown of TROY expression inhibits GBM cell invasion, increases sensitivity to temozolomide, and prolongs survival in an intracranial xenograft model. Propentofylline (PPF), an atypical synthetic methylxanthine compound, has been extensively studied in Phase II and Phase III clinical trials for Alzheimer's disease and vascular dementia where it has demonstrated blood-brain permeability and minimal adverse side effects. Here we showed that PPF decreased GBM cell expression of TROY, inhibited glioma cell invasion, and sensitized GBM cells to TMZ. Mechanistically, PPF decreased glioma cell invasion by modulating TROY expression and downstream signaling, including AKT, NF-κB, and Rac1 activation. Thus, PPF may provide a pharmacologic approach to target TROY, inhibit cell invasion, and reduce therapeutic resistance in GBM.

Trichosanthin suppresses the proliferation of glioma cells by inhibiting LGR5 expression and the Wnt/β-catenin signaling pathway.

Studies have indicated that trichosanthin (TCS), a bioactive protein extracted and purified from the tuberous root of Trichosanthes kirilowii (a well-known traditional Chinese medicinal plant), produces antitumor effects on various types of cancer cells. However, the effects of TCS on glioma cells are poorly understood. The objective of this study was to investigate the antitumor effects of TCS on the U87 and U251 cell lines. The in vitro effects of TCS on these two cell lines were determined using a Cell Counting Kit-8 (CCK-8) assay, Annexin V-FITC staining, DAPI staining, Transwell assays, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assays, 5,5′,6,6′-tetrachloro-1,1′,3,3′-tetraethyl-imidacar-bocyanine iodide (JC-1) staining and western blotting, which was utilized to assess the expression of leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) and key proteins in the Wnt/β-catenin signaling pathway. Our data indicated that TCS inhibited the proliferation of glioma cells in a dose- and time-dependent manner and played a role in inhibiting glioma cell invasion and migration. Additional investigation revealed that the expression levels of LGR5 and of key proteins in the Wnt/β-catenin signaling pathway were markedly decreased after TCS treatment. The results suggest that TCS may induce apoptosis in glioma cells by targeting LGR5 and repressing the Wnt/β-catenin signaling pathway. In the future, in vivo experiments should be conducted to examine the potential use of this compound as a novel therapeutic agent for gliomas.

Upregulation of miR-181s reverses mesenchymal transition by targeting KPNA4 in glioblastoma.

The goal of this work was to explore the most effective miRNAs affecting glioblastoma multiforme (GBM) phenotype transition and malignant progression. We annotated 491 TCGA samples’ miRNA expression profiles according to their mRNA-based subtypes and found that the mesenchymal tumors had significantly decreased miR-181 family expression compared with the other three subtypes while the proneural subtype harbored extremely high miR-181 family expression. Patients with high miR-181 family expression had longer overall survival (p = 0.0031). We also confirmed that NF-κB-targeting genes and the EMT (epithelial-mesenchymal transition) pathway were inversely correlated with miR-181 family expression and that the entire miR-181 family inhibited glioma cell invasion and proliferation; of these, miR-181b was the most effective suppressor. Furthermore, miR-181b was validated to suppress EMT by targeting KPNA4 and was associated with survival outcome in the TCGA and CGGA datasets and in another independent cohort. The EMT-inhibitory effect of miR-181b was lost after KPNA4 expression was restored. We also identified the antitumorigenic activity of miR-181b in vitro and in vivo. Our results showed that miR-181 family expression was closely correlated with TCGA subtypes and patients’ overall survival, indicating that miR-181b, a tumor-suppressive miRNA, could be a novel therapeutic candidate for treating gliomas.