Interplay of VEGFa and MMP2 regulates invasion of glioblastoma

Doxorubicin-loaded liposome-like particles embedded in chitosan/hyaluronic acid-based hydrogels as a controlled drug release model for local treatment of glioblastoma

Glioblastoma (GBM) resection and medication treatment are limited, and local drug therapies are required. This study aims to create a hybrid system comprising liposome-like particles (LLP-DOX) encapsulated in chitosan/hyaluronic acid/polyethyleneimine (CHI/HA/PEI) hydrogels, enabling controlled local delivery of doxorubicin (DOX) into the resection cavity for treating GBM. CHI/HA/PEI hydrogels were characterized morphologically, physically, chemically, mechanically, and thermally. Findings revealed a high network and compact micro-network structure, along with enhanced physical and thermal stability compared to CHI/HA hydrogels. Simultaneously, drug release from CHI/HA/PEI/LLP-DOX hydrogels was assessed, revealing continuous and controlled release up to the 148th hour, with no significant burst release. Cell studies showed that CHI/HA/PEI hydrogels are biocompatible with low genotoxicity. Additionally, LLP-DOX-loaded CHI/HA/PEI hydrogels significantly decreased cell viability and gene expression levels compared to LLP-DOX alone. It was also observed that the viability of GBM spheroids decreased over time when interacting with CHI/HA/PEI/LLP-DOX hydrogels, accompanied by a reduction in total surface area and an increase in apoptotic tendencies. In this study, we hypothesized that creating a hybrid drug delivery system by encapsulating DOX-loaded LLPs within a CHI/HA/PEI hydrogel matrix could achieve sustained drug release, improve anticancer efficacy via localized treatment, and effectively mitigate GBM progression for 3D microtissues.

Glioma and post-translational modifications: A complex relationship

Post-translational modifications (PTMs) are common covalent processes in biochemical pathways that alter protein function and activity. These modifications occur through proteolytic cleavage or attachment of modifying groups, such as phosphoryl, methyl, glycosyl, or acetyl groups, with one or more amino acid residues of a single protein. Some PTMs also present crosstalk abilities that affect both protein functionality and structure, creating new proteoforms. Any alteration in organism homeostasis may be a cancer hallmark. Cataloging PTMs and consequently, emerging proteoforms, present new therapeutic targets, approaches, and opportunities to discover additional discriminatory biomarkers in disease diagnostics. In this review, we focus on experimentally confirmed PTMs and their potential crosstalk in glioma research to introduce new opportunities for this tumor type, which emerge within the PTMomics area.

High VEGFA Expression Is Associated with Improved Progression-Free Survival after Bevacizumab Treatment in Recurrent Glioblastoma

Glioblastoma (GB) is one of the deadliest human cancers. Many GB patients do not respond to treatment, and inevitably die within a median of 15-18 months post-diagnosis, highlighting the need for reliable biomarkers to aid clinical management and treatment evaluation. The GB microenvironment holds tremendous potential as a source of biomarkers; several proteins such as MMP-2, MMP-9, YKL40, and VEGFA have been identified as being differentially expressed in GB patient samples. Still to date, none of these proteins have been translated into relevant clinical biomarkers. This study evaluated the expression of MMP-2, MMP-9, YKL40, and VEGFA in a series of GBs and their impact on patient outcome. High levels of VEGFA expression were significantly associated with improved progression-free survival after bevacizumab treatment, thus having potential as a tissue biomarker for predicting patients' response to bevacizumab. Noteworthily, VEGFA expression was not associated with patient outcome after temozolomide treatment. To a lesser extent, YKL40 also provided significant information regarding the extent of bevacizumab treatment. This study highlights the importance of studying secretome-associated proteins as GB biomarkers and identifies VEGFA as a promising marker for predicting response to bevacizumab.

PRMT5 promotes retinoblastoma development

Epigenetic mechanism, including DNA methylation and histone modifications, contributes to alterations in the expression patterns of genes regulating malignant phenotype of cancer cells. However, the epigenetic modulation of vascular endothelial growth factor-A (VEGFA) in retinoblastoma (RB) has not been clearly established. We aimed to examine the epigenetic regulation of VEGFA by protein arginine methyltransferase 5 (PRMT5) in RB. Using the GEO database, we identified VEGFA as a pathogenic gene in RB. Silencing of VEGFA in SO-RB50 and Y79 cells inhibited cell proliferation, angiogenesis, and migration, promoted apoptosis, and suppressed tumor growth in mice. Mechanistically, PRMT5 promoted H3K4me3 modification of the VEGFA promoter, thereby activating VEGFA expression. VEGFA could regulate the expression of MMP1, MMP2, and MMP9. Further silencing of VEGFA in RB cells overexpressing PRMT5 constrained the expression of MMP1, MMP2 and MMP9, and suppressed the growth of tumors in mice. In conclusion, this study clarifies that the depletion of PRMT5 reduces H3K4me3-mediated VEGFA transcription and retards the carcinogenesis of RB by suppressing the expression of MMPs.

Mechanism and function of miR-140 in human cancers: A review and in silico study

MicroRNA-140 (miR-140) acts as a tumor suppressor and plays a vital role in cell biological functions such as cell proliferation, apoptosis, and DNA repair. The expression of this miRNA has been shown to be considerably decreased in cancer tissues and cell lines compared with normal adjacent tissues. Consequently, aberrant expression of some miR-140 target genes can lead to the initiation and progression of various human cancers, such as breast cancer, gastrointestinal cancers, lung cancer, and prostate cancer. The dysregulation of the miR-140 network also affects cell proliferation, invasion, metastasis, and apoptosis of cancer cells by affecting various signaling pathways. Besides, up-regulation of miR-140 could enhance the efficacy of chemotherapeutic agents in different cancer. We aimed to cover most aspects of miR-140 function in cancer development and address its importance in different stages of cancer progression.

Novel Brain-Stiffness-Mimicking Matrix Gel Enables Comprehensive Invasion Analysis of 3D Cultured GBM Cells

Glioblastoma (GBM) is the most common malignant primary brain tumor in adults, which is fast growing and tends to invade surrounding normal brain tissues. Uncovering the molecular and cellular mechanisms of GBM high invasion potential is of great importance for the treatment and prognostic prediction. However, the commonly used two-dimensional (2D) cell culture and analysis system suffers from lack of the heterogeneity and in vivo property of brain tissues. Here, we established a three-dimensional (3D) cell culture-based analysis system that could better recapitulate the heterogeneity of GBM and mimic the in vivo conditions in the brain. The GBM cell lines, DBTRG and U251, were cultured by hanging drop culture into the GBM multicellular spheroids, which were embedded in the optimized 3D brain-stiffness-mimicking matrix gel (0.5 mg/ml Collagen Ⅰ + 3 mg/ml Matrigel+ 3.3 mg/ml Hyaluronic Acid (HA)). The biochemical composition of the optimized matrix gel is similar to that of the brain microenvironment, and the elastic modulus is close to that of the brain tissue. The dynamics of the GBM spheroids was examined using high-content imaging for 60 h, and four metrics including invasion distance, invasion area, single-cell invasion velocity, and directionality were employed to quantify the invasion capacity. The result showed that DBTRG cells possess higher invasion capacity than U251 cells, which was consistent with the results of the classic transwell test. Transcriptome analysis of both cell lines was performed to explore the underlying molecular mechanisms. Our novel brain-stiffness-mimicking matrix gel enables comprehensive invasion analysis of the 3D cultured GBM cells and provides a model basis for in-depth exploration of the mechanisms regulating GBM invasion including the interaction between GBM cells and brain stroma.

Yiqi Tongluo Fang could preventive and delayed development and formation of diabetic retinopathy through antioxidant and anti-inflammatory effects

BACKGROUND

Yiqi Tongluo Fang (YQTLF) is an effective prescription for the treatment of diabetic retinopathy (DR), but its mechanism of action remains unclear.

METHOD

The content of YQTLF was determined using liquid and gas chromatography-mass spectrometry (LC-MS and GC-MS, respectively). Twenty-five Sprague Dawley (SD) rats were randomly selected as the normal control group. One hundred SD streptozotocin-induced diabetes (type 1) rats were randomly divided into diabetic control, diabetic+insulin+ calcium dobesilate (CaD), and diabetic+insulin+ YQTLF groups, with 25 rats in each group. Bodyweight level was measured every 2 weeks. After 12 weeks of gavage, the glucose levels, lipids, oxidative stress, inflammation, retinal histopathology, and the blood-retinal barrier were assessed in each group. The p38 MAPK pathway was changed to explore its internal mechanism. The measurement data were expressed as mean ± standard deviation, and different statistical methods were used according to a normal distribution, square error, or not.

RESULTS

A total of 1024 valid peaks were identified in YQTLF using GC-MS. YQTLF significantly lowered the fasting blood glucose levels in diabetic rats. YQTLF early inhibited changes in retinal histology, capillaries, cells, and tight junction proteins (such as ZO-1, occludin, claudin-5, and VE-cadherin) before the formation and development of DR. These findings correlated with the alleviation of glucolipid metabolism, inflammation, and oxidative stress. The lncRNA MALAT1 and the PRC 2/p38 MAPK-related pathway, such as the expression of EZH2, SUZ12, EED, p38 MAPK, MMP-9, and VEGFR, were also correlated.

CONCLUSION

We have demonstrated the molecular and cellular mechanisms underlying the preventive and delayed development and formation of DR. YQTLF prevents changes in dyslipidemia, retinal histology, capillaries, cells, and tight junction proteins. These protective effects appear to be linked to its antioxidant and anti-inflammatory effects, which prevent the activation of intracellular signaling pathways, such as the lncRNA MALAT1 and PRC 2/p38 MAPK-related pathway.

Platycodon D-induced A549 cell apoptosis through RRM1-regulated p53/VEGF/MMP2 pathway

BACKGROUND

Lung cancer is one of the leading causes of cancer-related deaths worldwide. Platycodin D (PD), a major pharmacological constituent from the Chinese medicinal herb named Platycodonis Radix, has shown potent anti-tumor activity. Also, it is also reported that PD could inhibit cellular growth in the non-small-cell lung carcinoma (NSCLC) A549 cell line. However, the underlying mechanism is not fully clarified.

METHODS

Cell proliferation was measured by MTT assay. Annexin V and propidium iodide (PI) assay were employed to study the apoptosis effects of PD on A549 cells. Western blot analysis was used to evaluate protein expression. Also, we used a siRNA against p53, as well as a plasmid-based RRM1 over-expression to investigate their functions.

RESULTS

It demonstrated PD inhibited A549 cell proliferation in a dose- and time-dependent manner. Further investigations showed that PD induced cell apoptosis, which was supported by dose-dependent and time-dependent caspase-3 activation and p53/VEGF/MMP2 pathway regulation. Also, PD demonstrated the inhibition effect of ribonucleotide reductase M1 (RRM1), whose role in various tumors is contradictory. Remarkably, in this work, RRM1 overexpression in A549 cells could have a negative impact on the regulation of the p53/VEGF/MMP2 pathway induced by PD treatment. Note as well that RRM1 overexpression also attenuated cell apoptosis and inhibition of cell proliferation of A549 treated with PD.

CONCLUSION

The results suggested that PD could inhibit A549 cell proliferation and induce cell apoptosis by regulating p53/VEGF/MMP2 pathway, in which RRM1 plays an important role directly.

A System Bioinformatics Approach Predicts the Molecular Mechanism Underlying the Course of Action of Radix Salviae Reverses GBM Effects

Objective

This study used in vitro techniques to investigate the therapeutic effect of Radix Salviae on human glioblastoma and decode its underlying molecular mechanism.

Methods

The active components and targets of the Radix Salviae were identified from the Traditional Chinese Medicine Systems Pharmacology Database (TCMSP). The targets of human glioblastoma were obtained from the GeneCards Database. The Radix Salviae-mediated antiglioblastoma was evaluated by Gene Ontology (GO) analyses and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses. Finally, mechanism of action of Radix Salviae against human glioblastoma was deduced by molecular docking and experiments.

Results

We screened 66 active ingredients and 45 targets of the Radix Salviae. The enrichment analysis based on the targets mentioned above suggested a possible role in protein phosphorylation, cell transcription, apoptosis, and inflammatory factor signaling pathways. Further study demonstrated that cryptotanshinone, an essential component of Radix Salviae, played a significant role in killing human glioblastoma cells and protecting the body by inhibiting the AKT, IKB, and STAT3 signaling pathways.

Conclusions

Radix Salviae could inhibit the proliferation and invasion of human glioblastoma by regulating STAT3, Akt, and IKB signaling pathways. Radix Salviae has potential therapeutic value in the future for human glioblastoma.

The Tumor Suppressor MTUS1/ATIP1 Modulates Tumor Promotion in Glioma: Association with Epigenetics and DNA Repair

Simple Summary

Despite multidisciplinary treatments, survival remains poor in glioma patients. Although novel therapeutic approaches are being explored, no outstanding effects on the survival have been achieved so far, which substantiates the need to develop new therapeutic strategies. To understand the mechanisms responsible for its high malignancy and obligatory recurrence, we examined the impact of MTUS1, a tumor-suppressor gene (TSG), coding for ATIP1, in glioma malignancy as well as how its expression might influence glioma therapy. We confirmed that in glioma cells, elevated ATIP1 expression damps tumor progression by mitigating proliferation and motility. Additionally, MTUS1/ATIP1 can be used as a biological marker to predict therapy outcomes. In glioma cell lines, glioma sphere cultures (GSC), high-grade glioma (HGG) and especially in glioma recurrence, MTUS1/ATIP1 expression is downregulated, probably by promoter hypermethylation. However, in GBM, high ATIP1 expression might interfere with radiation-therapy since elevated expression of MTUS1/ATIP1 drives double-strand break (DSB) DNA repair.

Abstract

Glioblastoma (GBM) is a highly aggressive brain tumor. Resistance mechanisms in GBM present an array of challenges to understand its biology and to develop novel therapeutic strategies. We investigated the role of a TSG, MTUS1/ATIP1 in glioma. Glioma specimen, cells and low passage GBM sphere cultures (GSC) were analyzed for MTUS1/ATIP1 expression at the RNA and protein level. Methylation analyses were done by bisulfite sequencing (BSS). The consequence of chemotherapy and irradiation on ATIP1 expression and the influence of different cellular ATIP1 levels on survival was examined in vitro and in vivo. MTUS1/ATIP1 was downregulated in high-grade glioma (HGG), GSC and GBM cells and hypermethylation at the ATIP1 promoter region seems to be at least partially responsible for this downregulation. ATIP1 overexpression significantly reduced glioma progression by mitigating cell motility, proliferation and facilitate cell death. In glioma-bearing mice, elevated MTUS1/ATIP1 expression prolonged their survival. Chemotherapy, as well as irradiation, recovered ATIP1 expression both in vitro and in vivo. Surprisingly, ATIP1 overexpression increased irradiation-induced DNA-damage repair, resulting in radio-resistance. Our findings indicate that MTUS1/ATIP1 serves as TSG-regulating gliomagenesis, progression and therapy resistance. In HGG, higher MTUS1/ATIP1 expression might interfere with tumor irradiation therapy.

Modulation of the ERK1/2-MMP-2 pathway in the sclera of guinea pigs following induction of myopia by flickering light

It has been shown that flickering light can affect the development of eyeballs. However, the exact mechanism remains unclear. The ERK1/2-MMP-2 pathway is a classic pathway involved in the modulation of the extracellular matrix (ECM) in cancer tissues. However, to the best of our knowledge, the role of this pathway in modulating the scleral ECM in myopia has not been previously examined. The present study aimed to determine the effects of the ERK1/2-MMP-2 pathway on the formation of flickering light-induced myopia (FLM). Guinea pigs were raised under illumination at a flash rate of 0.5 Hz for 6 weeks to induce FLM. Peribulbar injections of dimethylsulfoxide or PD98059 (an inhibitor of phospho-ERK1/2) were administered starting at the third week of FLM modeling. Refraction was measured prior to and following treatments. The thickness of the posterior sclera (PS) was measured under a light microscope following H&E staining. The mRNA levels of MMP-2 were detected by the reverse transcription-quantitative PCR assay. The expression levels of MMP-2 and ERK1/2 were assayed by western blot and immunohistochemical analyses. Following 6 weeks of treatment, the refraction of the FLM group became more myopic compared with that of the control group, while PD98059 treatment inhibited the changes noted in the refraction. A marked reduction in the thickness of PS was observed in the FLM group, while PD98059 inhibited the remodeling of PS. In addition, the expression levels of MMP-2 and protein levels of phospho-ERK1/2 were increased in the FLM group, while PD98059 significantly inhibited MMP-2 mRNA and protein levels. These results indicated that ERK1/2-MMP-2 may be involved in the formation of FLM in guinea pigs by regulating the remodeling of PS.

Improved Antiglioblastoma Activity and BBB Permeability by Conjugation of Paclitaxel to a Cell-Penetrative MMP-2-Cleavable Peptide

In order to solve the problems of receptor promiscuity and poor blood-brain barrier (BBB) penetration in the treatment of glioblastomas (GBM), a novel dual-functional nanocomplex drug delivery system is developed based on the strategy of peptide-drug conjugates. In this study, SynB3-PVGLIG-PTX is designed and screened out by matrix metalloproteinase-2 (MMP-2), to which it exhibits the best affinity. The MMP-2-sensitive peptide (PVGLIG) and a cell-penetration peptide (SynB3) are combined to form a dual-functional peptide. Moreover, as a drug-peptide nanocomplex, SynB3-PVGLIG-PTX exhibited a high potential to form an aggregation with good solubility that can release paclitaxel (PTX) through the cleavage of MMP-2. From a functional perspective, it is found that SynB3-PVGLIG-PTX can specifically inhibit the proliferation, migration, and invasion of GBM cells in vitro in the presence of MMP-2, in contrast to that observed in MMP-2 siRNA transfected cells. Further investigation in vivo shows that SynB3-PVGLIG-PTX easily enters the brain of U87MG xenograft nude mice and can generate a better suppressive effect on GBM through a controlled release of PTX from SynB3-PVGLIG-PTX compared with PTX and temozolomide. Thus, it is proposed that SynB3-PVGLIG-PTX can be used as a novel drug-loading delivery system to treat GBM due to its specificity and BBB permeability.

Collagen type VIII alpha 2 chain (COL8A2), an important component of the basement membrane of the corneal endothelium, facilitates the malignant development of glioblastoma cells via inducing EMT

Glioblastoma (GBM) is one of the most lethal tumor of all human cancers. Due to its poor response to chemotherapy and radiotherapy as well as its high rate of recurrence after treatment, the treatment is still undesired. The identification of potential related genes and bio-markers in the development of GBM could provide some new targets for the treatment of GBM. Our purpose in this study was to evaluate the mission of COL8A2 in GBM. Combined with TCGA, Oncomine databases, CGGA, GEPIA website and qRT-PCR analyses, we found that COL8A2 was up-regulated both in GBM tissues and cells compared to the controls. Moreover, the high COL8A2 expression was associated with the shorter overall survival of patients with GBM. The expression of COL8A2 was also positively correlated with metastasis-associated genes including vimentin, snail, slug, MMP2 and MMP7 according to GEPIA website. Knockdown of COL8A2 could suppress the cell proliferation, cell migration and invasion, whereas the overexpression of COL8A2 significantly expedited these processes. What's more, the outcome of western blot analysis manifested that COL8A2 could induced the expression of vimentin, snail, slug, MMP2 and MMP7. Taken together, COL8A2 activated cell proliferation, cell migration and invasion via raising the relative expression of EMT-related proteins in GBM. Therefore, our investigation suggests the oncogenic role of COL8A2 in GBM and provides a potential application of COL8A2 for GBM therapy.

To Become or Not to Become Tumorigenic: Subventricular Zone Versus Hippocampal Neural Stem Cells

Neural stem cells (NSCs) persist in the adult mammalian brain in two neurogenic regions: the subventricular zone lining the lateral ventricles and the dentate gyrus of the hippocampus. Compelling evidence suggests that NSCs of the subventricular zone could be the cell type of origin of glioblastoma, the most devastating brain tumor. Studies in glioblastoma patients revealed that NSCs of the tumor-free subventricular zone, harbor cancer-driver mutations that were found in the tumor cells but were not present in normal cortical tissue. Endogenous mutagenesis can also take place in hippocampal NSCs. However, to date, no conclusive studies have linked hippocampal mutations with glioblastoma development. In addition, glioblastoma cells often invade or are closely located to the subventricular zone, whereas they do not tend to infiltrate into the hippocampus. In this review we will analyze possible causes by which subventricular zone NSCs might be more susceptible to malignant transformation than their hippocampal counterparts. Cellular and molecular differences between the two neurogenic niches, as well as genotypic and phenotypic characteristics of their respective NSCs will be discussed regarding why the cell type originating glioblastoma brain tumors has been linked mainly to subventricular zone, but not to hippocampal NSCs.

Functional and Structural Aspects of La Protein Overexpression in Lung Cancer

La is an abundant phosphoprotein that protects polymerase III transcripts from 3'-5' exonucleolytic degradation and facilitates their folding. Consisting of the evolutionary conserved La motif (LAM) and two consecutive RNA Recognition Motifs (RRMs), La was also found to bind additional RNA transcripts or RNA domains like internal ribosome entry site (IRES), through sequence-independent binding modes which are poorly understood. Although it has been reported overexpressed in certain cancer types and depletion of its expression sensitizes cancer cells to certain chemotherapeutic agents, its role in cancer remains essentially uncharacterized. Herein, we study the effects of La overexpression in A549 lung adenocarcinoma cells, which leads to increased cell proliferation and motility. Expression profiling of several transcription and translation factors indicated that La overexpression leads to downregulation of global translation through hypophosphorylation of 4E-BPs and upregulation of IRES-mediated translation. Moreover, analysis of La localization after nutrition deprivation of the transfected cells showed a normal distribution in the nucleus and nucleoli. Although the RNA binding capacity of La has been primarily linked to the synergy between the conserved LAM and RRM1 domains which act as a module, we show that recombinant stand-alone LAM can specifically bind a pre-tRNA ligand, based on binding experiments combined with NMR analysis. We propose that LAM RNA binding properties could support the expanding and diverse RNA ligand repertoire of La, thus promoting its modulatory role, both under normal and pathogenic conditions like cancer.

Circular RNA COL1A2 promotes angiogenesis via regulating miR-29b/VEGF axis in diabetic retinopathy

AIMS

The dysregulation of circular RNAs (circRNAs) has been implicated in the progression of diabetic retinopathy (DR). This study aims to explore the role and underlying mechanism of hsa_circ_0081108 (circCOL1A2) in DR.

MATERIALS AND METHODS

circCOL1A2, vascular endothelial growth factor (VEGF) and miR-29b expression levels in human retinal microvascular endothelial cells (hRMECs) were detected by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and Western blotting. The biological functions of hRMECs were evaluated by MTT, transwell, tube formation, and vascular permeability assays, respectively. The interaction between miR-29b and circCOL1A2/VEGF was determined by dual luciferase assay. The release of VEGF was examined by ELISA. The in vivo role of circCOL1A2 was further verified in streptozotocin (STZ)-induced DR in mice. The pathological changes and VEGF expression in retinal tissues were detected by hematoxylin and eosin (HE) and immunohistochemical staining.

KEY FINDINGS

High glucose (HG) challenge led to increased circCOL1A2, VEGF, MMP-2, MMP-9 levels, but decreased miR-29b level in hRMECs. In addition, circCOL1A2 sponged miR-29b to promote VEGF expression. Silencing of circCOL1A2 inhibited HG-induced proliferation, migration, angiogenesis and vascular permeability of hRMECs via enhancing miR-29b expression. Moreover, circCOL1A2/miR-29b axis participated in HG-induced increase in angiogenesis-related protein expression. Finally, circCOL1A2 knockdown suppressed angiogenesis via regulating miR-29b/VEGF axis in DR mice.

SIGNIFICANCE

circCOL1A2 facilities angiogenesis during the pathological progression of DR via regulating miR-29b/VEGF axis, suggesting that targeting circCOL1A2 may be a potential treatment for DR.

Insights into the Regulation of Tumor Angiogenesis by Micro-RNAs

One of the hallmarks of cancer is angiogenesis, a series of events leading to the formation of the abnormal vascular network required for tumor growth, development, progression, and metastasis. MicroRNAs (miRNAs) are short, single-stranded, non-coding RNAs whose functions include modulation of the expression of pro- and anti-angiogenic factors and regulation of the function of vascular endothelial cells. Vascular-associated microRNAs can be either pro- or anti-angiogenic. In cancer, miRNA expression levels are deregulated and typically vary during tumor progression. Experimental data indicate that the tumor phenotype can be modified by targeting miRNA expression. Based on these observations, miRNAs may be promising targets for the development of novel anti-angiogenic therapies. This review discusses the role of various miRNAs and their targets in tumor angiogenesis, describes the strategies and challenges of miRNA-based anti-angiogenic therapies and explores the potential use of miRNAs as biomarkers for anti-angiogenic therapy response.

High gene expression levels of VEGFA and CXCL8 in the peritumoral brain zone are associated with the recurrence of glioblastoma: A bioinformatics analysis

The present study aimed to identify differentially regulated genes between the peritumoral brain zone (PBZ) and tumor core (TC) of glioblastoma (GBM), to elucidate the underlying molecular mechanisms and provide a target for the treatment of tumors. The GSE13276 and GSE116520 datasets were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) for the PBZ and TC were obtained using the GEO2R tool. The bioinformatics and evolutionary genomics online tool Venn was used to identify common DEGs between the two datasets. The Database for Annotation, Visualization, and Integrated Discovery online tool was used to analyze enriched pathways of the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The Search Tool for the Retrieval of Interacting Genes/Proteins online tool was used to construct a protein-protein interaction (PPI) network of DEGs. Hub genes were identified using Cytohubba, a plug-in for Cytoscape. The Gene Expression Profiling Interactive Analysis (GEPIA) database was utilized to perform survival analysis. In total, 75 DEGs, including 12 upregulated and 63 downregulated genes, were identified. In the GO term analysis, these DEGs were mainly enriched in ‘regulation of angiogenesis’ and ‘central nervous system development’. Furthermore, in the KEGG pathway analysis, the DEGs were mainly enriched in ‘bladder cancer’ and ‘endocytosis’. When filtering the results of the PPI network analysis using Cytohubba, a total of 10 hub genes, including proteolipid protein 1, myelin associated oligodendrocyte basic protein, contactin 2, myelin oligodendrocyte glycoprotein, myelin basic protein, myelin associated glycoprotein, SRY-box transcription factor 10, C-X-C motif chemokine ligand 8 (CXCL8), vascular endothelial growth factor A (VEGFA) and plasmolipin, were identified. These hub genes were further subjected to GO term and KEGG pathway analysis, and were revealed to be enriched in ‘central nervous system development’, ‘bladder cancer’ and ‘rheumatoid arthritis’. These hub genes were used to perform survival analysis using the GEPIA database, and it was determined that VEGFA and CXCL8 were significantly associated with a reduction in the overall survival of patients with GBM. In conclusion, the results suggest that the recurrence of GBM is associated with high gene expression levels VEGFA and CXCL8, and the development of the central nervous system.

Down-regulation of STIP1 regulate apoptosis and invasion of glioma cells via TRAP1/AKT signaling pathway

BACKGROUND

In recent years, many studies have confirmed that STIP1 (phosphorylation-induced protein 1) is involved in the development and progression of various tumors. However, its potential role in glioma progression and the underlying mechanisms of glioma development remain unclear.

METHODS

We analyzed the expression of STIP1 in 35 human glioma tissue specimens of different grades, using 6 normal brain tissues for comparison. We transfected U87 and U251 cell lines with small interfering RNA (siRNA) to downregulate STIP1, and set up a negative control group and a blank group for comparison. The MTT assay was used to detect cell proliferation, and cell cycle progression and apoptosis were analyzed through flow cytometry. Transwell experiments were employed to detect the invasion and migration of STIP1-depleted and control U87 and U251 cells and western blotting was used to detect the expression of TRAP1/Akt pathway proteins. In addition, immunohistochemical analysis was used to reveal differences in expression and localization between transplanted tumor specimens of each group.

RESULTS

We observed a high expression of STIP1 in glioblastoma, MTT assay revealed a decreased cell proliferation rate in the STIP1-downregulated cells. Cell cycle analysis revealed an increased proportion of cells in G1 phase, as well as an increase in apoptosis, upon STIP1 downregulation. Western blotting showed that TRAP1, pAkt, and MMP2 expression was decreased upon STIP1 downregulation. In addition, TRAP1, ki-67, and MMP2 displayed a decreased expression in vivo.

CONCLUSIONS

STIP1 is highly expressed in glioblastoma compared to normal brain tissues. Downregulation of STIP1 in glioma cells reduces cell proliferation rate and invasion and increases cell apoptosis.

LncRNA-MALAT1 promotes neovascularization in diabetic retinopathy through regulating miR-125b/VE-cadherin axis

Background: Diabetic retinopathy (DR) is currently the leading cause of blindness and visual disability in adults with diabetes mellitus (DM). Neovascularization has been identified as an important clinical property in DR, however, the exact mechanisms in DR neovascularization are still unclear and need further elucidation.

Methods: Quantitative real-time PCR (qRT-PCR) was conducted to detect the expression level of long non-coding RNA (lncRNA)-metastasis associated lung adenocarcinoma transcript 1 (MALAT1), miR-125b and vascular endothelial-cadherin (VE-cadherin) in human retina microvascular endothelial cells (hRMECs) treated with high glucose (HG). Luciferase assay was used to detect interaction of MALAT1 with miR-125b and miR-125b with VE-cadherin. MTT assay, transwell assay, tube formation assay and vascular permeability assay were conducted to detect the cell viability, migration tube formation ability and permeability of hRMECs, respectively. ELISA was used to examine the release of VE-cadherin and vascular endothelial growth factor (VEGF). Western blotting was used to access the protein expression of VE-cadherin, VEGF, β-catenin, matrix metalloproteinase (MMP) 2 (MMP2) and MMP9.

Results: MALAT1 and VE-cadherin were up-regulated while miR-125b was down-regulated in hRMECs treated with HG. MALAT1 could competitively bind to miR-125b against VE-cadherin at the site of 3′-untranslated region (3′-UTR), leading to the up-regulation of VE-cadherin. Knockdown of MALAT1 inhibited the proliferation, migration, tube formation and vascular permeability of hRMECs induced by HG through up-regulating miR-125b. Furthermore, we found the deletion of MALAT1 suppressed the VE-cadherin/β-catenin complex and neovascularization related proteins expression, which was up-regulated by HG.

Conclusion: Knockdown of MALAT1 inhibited cell proliferation, migration and angiogenesis of hRMECs via suppressing the VE-cadherin/β-catenin complex through targeting miR-125b. Inhibition of MALAT1 may serve as a potential target for anti-angiogenic therapy for DR.

Chemo-resistance of A172 glioblastoma cells is controlled by miR-1271-regulated Bcl-2

MicroRNAs (miRNAs) have been reported to exert important effects on the initiation, progression and metastasis of glioblastoma multiforme (GBM). In this study, we aimed to explore the regulation role of miR-1271 on the development of GBM. We found that miR-1271 was a Bcl-2-targeting miRNA, and the levels of miR-1271was decreased in samples from patients with GBM, compared with those from corresponding normal tissue samples. On the other hand, the levels of miR-1271 were inversely related to the levels of Bcl-2, which have been significantly increased in GBM samples. The overall survival was poorer in patients with low levels of miR-1271, compared to those with high levels of miR-1271. In vitro, the chemo-resistant cell survival mediated with Bcl-2 was inhibited by overexpression of miR-1271 and was enhanced by depletion of miR-1271. Thus, the chemo-resistance of GBM cells may be promoted after suppressing miR-1271 through cell survival mediated with Bcl-2. The prognosis of patients with GBM receiving chemotherapy may be improved by overexpressing miR-1271 in cancerous cells.

Plk1 promotes the migration of human lung adenocarcinoma epithelial cells via STAT3 signaling

Polo-like kinase (Plk)1 contributes to the development of human cancer via multiple mechanisms, such as promoting the migration of cancer cells. However, the mechanistic basis for the regulation of cell migration by Plk1 remains unknown. To address this question, the present study investigated the effect of Plk1 inhibition on the migration of human lung adenocarcinoma epithelial A549 cells and the molecular factors involved. A549 cells were treated with the Plk1 inhibitor, BI2536, and cell migration was evaluated with the wound-healing assay. The expression of matrix metallopeptidase (MMP)2, vascular endothelial growth factor (VEGF)A, total and phosphorylated signal transducer and activator of transcription (STAT)3 was assessed by western blotting and reverse transcription-polymerase chain reaction following Plk1 knockdown and/or STAT3 overexpression. The interaction between Plk1 and STAT3 was evaluated by co-immunoprecipitation. The levels of MMP2 and VEGFA were decreased by treatment with Plk1 inhibitor. The phosphorylation of STAT3, which acts upstream of MMP2 and VEGFA, was also decreased by Plk1 knockdown, an effect that was abrogated by STAT3 overexpression. In addition, Plk1 was detected to bind with STAT3 either directly or as part of a complex by co-immunoprecipitation experiments. These results indicated that Plk1 may promote the migration of A549 cells via regulation of STAT3 signaling.

Growth hormone-releasing hormone receptor antagonists modify molecular machinery in the progression of prostate cancer

BACKGROUND

Therapeutic strategies should be designed to transform aggressive prostate cancer phenotypes to a chronic situation. To evaluate the effects of the new growth hormone-releasing hormone receptor (GHRH-R) antagonists: MIA-602, MIA-606, and MIA-690 on processes associated with cancer progression as cell proliferation, adhesion, migration, and angiogenesis.

METHODS

We used three human prostate cell lines (RWPE-1, LNCaP, and PC3). We analyzed several molecules such as E-cadherin, β-catenin, Bcl2, Bax, p53, MMP2, MMP9, PCNA, and VEGF and signaling mechanisms that are involved on effects exerted by GHRH-R antagonists.

RESULTS

GHRH-R antagonists decreased cell viability and provoked a reduction in proliferation in LNCaP and PC3 cells. Moreover, GHRH-R antagonists caused a time-dependent increase of cell adhesion in all three cell lines and retarded the wound closure with the highest value with MIA-690 in PC3 cells. GHRH-R antagonists also provoked a large number of cells in SubG₀ phase revealing an increase in apoptotic cells in PC3 cell line.

CONCLUSIONS

Taken all together, GHRH-R antagonists of the MIAMI series appear to be inhibitors of tumor progression in prostate cancer and should be considered for use in future therapeutic strategies on this malignancy.

Regulation of tumor angiogenesis by microRNAs: State of the art

MicroRNAs (miRNAs, miRs) are small (21-25 nucleotides) endogenous and noncoding RNAs involved in many cellular processes such as apoptosis, development, proliferation, and differentiation via binding to the 3'-untranslated region of the target mRNA and inhibiting its translation. Angiogenesis is a hallmark of cancer, which provides oxygen and nutrition for tumor growth while removing deposits and wastes from the tumor microenvironment. There are many angiogenesis stimulators, among which vascular endothelial growth factor (VEGF) is the most well known. VEGF has three tyrosine kinase receptors, which, following VEGF binding, initiate proliferation, invasion, migration, and angiogenesis of endothelial cells in the tumor environment. One of the tumor microenvironment conditions that induce angiogenesis through increasing VEGF and its receptors expression is hypoxia. Several miRNAs have been identified that affect different targets in the tumor angiogenesis pathway. Most of these miRNAs affect VEGF and its tyrosine kinase receptors expression downstream of the hypoxia-inducible Factor 1 (HIF-1). This review focuses on tumor angiogenesis regulation by miRNAs and the mechanism underlying this regulation.

LncRNA TDRG1 enhances tumorigenicity in endometrial carcinoma by binding and targeting VEGF-A protein

Endometrial carcinoma is one of the most frequently diagnosed cancers in females. Long non-coding RNAs (lncRNAs) have been associated with cancer; its role in endometrial carcinoma is an emerging area of research. In this article, lncRNA TDRG1 expression in human endometrial carcinoma tissues and normal endometrial tissues was quantified by qRT-PCR. LncRNA TDRG1 was overexpressed or knocked-down in neither HEC-1B nor Ishikawa endometrial carcinoma cells, respectively, to assess cellular phenotype and expression of related molecules. Our results showed that lncRNA TDRG1 was significantly overexpressed in endometrial carcinoma tissues. Overexpression of lncRNA TDRG1 promoted endometrial carcinoma cell viability, invasion and migratory ability, inhibited apoptosis, and upregulated VEGF-A, PI3K, Bcl-2, MMP2 and survivin; knockdown of lncRNA TDRG1 had the opposite effects. LncRNA TDRG1 overexpression increased tumorigenicity in vivo and was associated with the upregulation of VEGF-A. RNA binding protein immunoprecipitation (RIP) assays confirmed that lncRNA TDRG1 directly binds to VEGF-A protein. Furthermore, knockdown of VEGFA in lncRNA TDRG1-overexpressing endometrial carcinoma cells reversed the effects of lncRNA TDRG1 on cell proliferation, invasion, migration and apoptosis. In conclusion, lncRNA TDRG1 may promote endometrial carcinoma cell proliferation and invasion by positively targeting VEGF-A and modulating relative genes.

Single nucleotide polymorphisms in the angiogenic and lymphangiogenic pathways are associated with lymphedema caused by Wuchereria bancrofti

Background

Lymphedema (LE) is a chronic clinical manifestation of filarial nematode infections characterized by lymphatic dysfunction and subsequent accumulation of protein-rich fluid in the interstitial space—lymphatic filariasis. A number of studies have identified single nucleotide polymorphisms (SNPs) associated with primary and secondary LE. To assess SNPs associated with LE caused by lymphatic filariasis, a cross-sectional study of unrelated Ghanaian volunteers was designed to genotype SNPs in 285 LE patients as cases and 682 infected patients without pathology as controls. One hundred thirty-one SNPs in 64 genes were genotyped. The genes were selected based on their roles in inflammatory processes, angiogenesis/lymphangiogenesis, and cell differentiation during tumorigenesis.

Results

Genetic associations with nominal significance were identified for five SNPs in three genes: vascular endothelial growth factor receptor-3 (VEGFR-3) rs75614493, two SNPs in matrix metalloprotease-2 (MMP-2) rs1030868 and rs2241145, and two SNPs in carcinoembryonic antigen-related cell adhesion molecule-1 (CEACAM-1) rs8110904 and rs8111171. Pathway analysis revealed an interplay of genes in the angiogenic/lymphangiogenic pathways. Plasma levels of both MMP-2 and CEACAM-1 were significantly higher in LE cases compared to controls. Functional characterization of the associated SNPs identified genotype GG of CEACAM-1 as the variant influencing the expression of plasma concentration, a novel finding observed in this study.

Conclusion

The SNP associations found in the MMP-2, CEACAM-1, and VEGFR-3 genes indicate that angiogenic/lymphangiogenic pathways are important in LE clinical development.

Electronic supplementary material

The online version of this article (10.1186/s40246-017-0121-7) contains supplementary material, which is available to authorized users.

Screening critical genes associated with malignant glioma using bioinformatics analysis

Malignant gliomas are high‑grade gliomas, which are derived from glial cells in the spine or brain. To examine the mechanisms underlying malignant gliomas in the present study, the expression profile of GSE54004, which included 12 grade II astrocytomas, 33 grade III astrocytomas and 98 grade IV astrocytomas, was downloaded from the Gene Expression Omnibus. Using the Limma package in R, the differentially expressed genes (DEGs) in grade III, vs. grade II astrocytoma, grade IV, vs. grade II astrocytoma, and grade IV, vs. grade III astrocytoma were analyzed. Venn diagram analysis and enrichment analyses were performed separately for the DEGs using VennPlex software and the Database for Annotation, Visualization and Integrated Discovery. Protein‑protein interaction (PPI) networks were visualized using Cytoscape software, and subsequent module analysis of the PPI networks was performed using the ClusterONE tool. Finally, glioma‑associated genes and glioma marker genes among the DEGs were identified using the CTD database. A total of 27, 1,446 and 776 DEGs were screened for the grade III, vs. grade II, grade IV, vs. grade II, and grade IV, vs. grade III astrocytoma comparison groups, respectively. Functional enrichment analyses showed that matrix metalloproteinase 9 (MMP9) and chitinase 3‑like 1 (CHI3L1) were enriched in the extracellular matrix and extracellular matrix structural constituent, respectively. In the PPI networks, annexin A1 (ANXA1) had a higher degree and MMP9 had interactions with vascular endothelial growth factor A (VEGFA). There were 10 common glioma marker genes between the grade IV, vs. grade II and the grade IV, vs. grade III comparison groups, including MMP9, CHI3L1, VEGFA and S100 calcium binding protein A4 (S100A4). This suggested that MMP9, CHI3L1, VEGFA, S100A4 and ANXA1 may be involved in the progression of malignant gliomas.

DUSP1 inhibits cell proliferation, metastasis and invasion and angiogenesis in gallbladder cancer

DUSP1/MKP1 is a dual-specific phosphatase that regulates MAPK activity and is known to play a key role in tumor biology. Its function in gallbladder cancer (GBC) remains largely unknown, however. By exploring its activities in two GBC cell lines (SGC996 and GBC-SD), DUSP1 was found to inhibit GBC cell proliferation, migration and invasion. Moreover, DUSP1 inhibited GBC growth and metastasis in nude mice subcutaneously xenografted with SGC996 cells. The tumor suppression appeared to be mediated via the DUSP1-pERK/MAPK-MMP2 signal pathway. Angiogenesis was associated with the tumor metastasis in the mouse model and was impaired by DUSP1, which suppressed VEGF expression. These results suggest that DUSP1 suppresses GBC growth and metastasis by targeting the DUSP1-pERK-MMP2/VEGF axis. Identification of the DUSP1-pERK-MMP2/VEGF signals may provide new biomarkers and/or therapeutic targets to better suppress GBC metastasis in the future.

VEGFA Involves in the Use of Fluvastatin and Zoledronate Against Breast Cancer

Our study aimed to identify key genes involved in the use of fluvastatin and zoledronate against breast cancer, as well as to investigate the roles of vascular endothelial growth factor A (VEGFA) in the malignant behaviors of breast cancer cells. The expression data GSE33552 was downloaded from Gene Expression Omnibus database, including mocked-, fluvastatin- and zoledronate-treated MDA-MB-231 cells. Differentially expressed genes (DEGs) were identified in fluvastatin- and zoledronate-treated cells using limma package, respectively. Pathway enrichment analysis and protein-protein interaction (PPI) network analysis were then performed. Then we used shRNA specifically targeting VEGFA (shVEGFA) to knock down the expression of VEGFA in MDA-MB-231 cells. Cell viability assay, scratch wound healing assay, Transwell invasion assay and flow cytometry were performed to explore the effects of VEGFA knockdown on the malignant behaviors of breast cancer cells. VEGFA was up-regulated in both fluvastatin- and zoledronate-treated breast cancer cells. Moreover, VEGFA was a hub node in PPI network. In addition, VEGFA was successfully knocked down in MDA-MB-231 cells by shVEGFA. Suppression of VEGFA promoted the migration and invasion of breast cancer MDA-MB-231 cells. Suppression of VEGFA inhibited the apoptosis of MDA-MB-231 cells. Our results indicate that up-regulation of VEGFA may prevent the progression of breast cancer after fluvastatin and zoledronate treatment via inducing cell apoptosis and inhibiting migration and invasion. VEGFA may serve as a potential prognostic indicator for clinical outcome in the management of breast cancer.

MicroRNA-140-5p inhibits cell proliferation and invasion by regulating VEGFA/MMP2 signaling in glioma

Glioma is the most common primary malignant tumor of the central nervous system, which results in both a poor prognosis and outcome because of the aggressive progression of disease, growth and resistance to surgery, chemotherapy, and radiotherapy. MiR-140-5p is a small, non-coding single-stranded RNA molecule, which was previously studied in the settings of human tongue cancer, hepatocellular carcinoma, and colorectal cancer. However, detailed data that formally demonstrate the contribution of miR-140-5p to glioma development are missing. Similarly, relatively little is known about the relationship of miR-140-5p, vascular endothelial growth factor A, and matrix metalloproteinase-2 in glioma progression. In this study, we found that miR-140-5p expression was significantly decreased in glioma tissues and in the glioma cell-lines U87 and U251 as compared with non-cancerous brain tissues by quantitative real-time polymerase chain reaction. In addition, miR-140-5p inhibited glioma cell proliferation and invasion and promoted glioma cell apoptosis both in vivo and in vitro. Interestingly, while the expression levels of miR-140-5p were higher in glioma cells, the messenger RNA or protein expression levels of vascular endothelial growth factor A and matrix metalloproteinase-2 were lower in glioma cells as determined by quantitative real-time polymerase chain reaction, western blot assay, and immunohistochemistry. By contrast, downregulation in the expression levels of miR-140-5p augmented the messenger RNA and protein expression levels of both vascular endothelial growth factor A and matrix metalloproteinase-2. These findings suggested that miR-140-5p inhibited glioma proliferation and invasion by regulating the vascular endothelial growth factor A/matrix metalloproteinase-2 signaling pathway both in vitro and in vivo.

Elucidation of the genetic and epigenetic landscape alterations in RNA binding proteins in glioblastoma

RNA binding proteins (RBPs) have been implicated in cancer development. An integrated bioinformatics analysis of RBPs (n = 1756) in various datasets (n = 11) revealed several genetic and epigenetically altered events among RBPs in glioblastoma (GBM). We identified 13 mutated and 472 differentially regulated RBPs in GBM samples. Mutations in AHNAK predicted poor prognosis. Copy number variation (CNV), DNA methylation and miRNA targeting contributed to RBP differential regulation. Two sets of differentially regulated RBPs that may be implicated in initial astrocytic transformation and glioma progression were identified. We have also identified a four RBP (NOL3, SUCLG1, HERC5 and AFF3) signature, having a unique expression pattern in glioma stem-like cells (GSCs), to be an independent poor prognostic indicator in GBM. RBP risk score derived from the signature also stratified GBM into low-risk and high-risk groups with significant survival difference. Silencing NOL3, SUCLG1 and HERC5 inhibited GSC maintenance. Gene set enrichment analysis of differentially regulated genes between high-risk and low-risk underscored the importance of inflammation, EMT and hypoxia in high-risk GBM. Thus, we provide a comprehensive overview of genetic and epigenetic regulation of RBPs in glioma development and progression.

Effects of RNA silencing of matrix metalloproteinase-2 on the growth of esophageal carcinoma cells in vivo

Esophageal carcinoma is one of the most common malignancies in China. Previous studies reported that matrix metalloproteinases (MMPs) have important roles in the progression and invasion of numerous types of solid tumors. Among the MMPs, MMP-2 has been closely associated with tumor growth and invasion. In the present study, a short hairpin RNA (shRNA) lentiviral expression vector targeting the MMP-2 gene was constructed in order to observe the inhibitory effect of MMP-2 gene silencing on the growth of the KYSE150 esophageal carcinoma cell line in vivo. Three small hairpin RNA sequences targeting MMP-2 were designed and cloned into lentiviral vectors. Following transfection of the lentiviral vectors into KTSE150 cells, MMP-2 mRNA and protein expression levels were examined by reverse transcription-quantitative polymerase chain reaction and western blotting, and the growth rate of cells was analyzed by MTT assays. Subsequently, tumor growth was assessed in nude mice. Lentivirus-mediated RNA interference effectively inhibited the expression of MMP-2 mRNA and protein in KYSE150 esophageal carcinoma cells, and suppressed the growth of esophageal carcinoma cells in vivo. The results of the present study suggested that lentivirus-mediated gene therapy targeting MMP-2 may be an attractive strategy for the treatment of esophageal carcinoma and justifies the performance of further studies on the application of lentivirus vectors to cancer gene therapy.

Comparative transcriptomics reveals similarities and differences between astrocytoma grades

Background

Astrocytomas are the most common primary brain tumors distinguished into four histological grades. Molecular analyses of individual astrocytoma grades have revealed detailed insights into genetic, transcriptomic and epigenetic alterations. This provides an excellent basis to identify similarities and differences between astrocytoma grades.

Methods

We utilized public omics data of all four astrocytoma grades focusing on pilocytic astrocytomas (PA I), diffuse astrocytomas (AS II), anaplastic astrocytomas (AS III) and glioblastomas (GBM IV) to identify similarities and differences using well-established bioinformatics and systems biology approaches. We further validated the expression and localization of Ang2 involved in angiogenesis using immunohistochemistry.

Results

Our analyses show similarities and differences between astrocytoma grades at the level of individual genes, signaling pathways and regulatory networks. We identified many differentially expressed genes that were either exclusively observed in a specific astrocytoma grade or commonly affected in specific subsets of astrocytoma grades in comparison to normal brain. Further, the number of differentially expressed genes generally increased with the astrocytoma grade with one major exception. The cytokine receptor pathway showed nearly the same number of differentially expressed genes in PA I and GBM IV and was further characterized by a significant overlap of commonly altered genes and an exclusive enrichment of overexpressed cancer genes in GBM IV. Additional analyses revealed a strong exclusive overexpression of CX3CL1 (fractalkine) and its receptor CX3CR1 in PA I possibly contributing to the absence of invasive growth. We further found that PA I was significantly associated with the mesenchymal subtype typically observed for very aggressive GBM IV. Expression of endothelial and mesenchymal markers (ANGPT2, CHI3L1) indicated a stronger contribution of the micro-environment to the manifestation of the mesenchymal subtype than the tumor biology itself. We further inferred a transcriptional regulatory network associated with specific expression differences distinguishing PA I from AS II, AS III and GBM IV. Major central transcriptional regulators were involved in brain development, cell cycle control, proliferation, apoptosis, chromatin remodeling or DNA methylation. Many of these regulators showed directly underlying DNA methylation changes in PA I or gene copy number mutations in AS II, AS III and GBM IV.

Conclusions

This computational study characterizes similarities and differences between all four astrocytoma grades confirming known and revealing novel insights into astrocytoma biology. Our findings represent a valuable resource for future computational and experimental studies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1939-9) contains supplementary material, which is available to authorized users.

Norcantharidin modulates miR-655-regulated SENP6 protein translation to suppresses invasion of glioblastoma cells

Norcantharidin (NCTD) is currently used as an anticancer drug for the treatment of some malignant cancers. However, whether it may have therapeutic effects on glioblastoma multiforme (GBM) remains unknown. Moreover, the underlying mechanisms have not been completely elucidated. Recently, SUMO-specific protease 6 (SENP6) has been shown as a tumor suppressor in some cancers. Nevertheless, whether it is involved in the pathogenesis of GBM has not been examined. Here, we studied the effects of NCTD on GBM cells. We found that NCTD dose-dependently increased SENP6 protein, but not messenger RNA (mRNA), in GBM cells, resulting in the suppression of cell invasion. Depletion of SENP6 in GBM cells significantly attenuated the NCTD-induced suppression of GBM cell invasion, while overexpression of SENP6 in GBM cells mimicked the effects of NCTD on cell invasion. Moreover, NCTD dose-dependently decreased the levels of microRNA-655 (miR-655), which bound to 3'-UTR of SENP6 mRNA to inhibit its translation. Overexpression of miR-655 decreased SENP6 in GBM cells, while depletion of miR-655 increased SENP6 protein in GBM cells. Taken together, our data demonstrates a previously unappreciated control of NCTD to suppress GBM cell invasion through modulation of miR-655-regulated SENP6 protein translation.

MiR-429 induces apoptosis of glioblastoma cell through Bcl-2

An essential role of microRNAs (miRNAs) has been acknowledged in the tumorigenesis of glioblastoma multiforme (GBM). Very recently, miR-429 was reported to have a potential of suppressing cancer growth. However, whether miR-429 may similarly regulate growth of GBM remains unknown. Here, we analyzed the levels of miR-429 and anti-apoptotic protein Bcl-2 in GBM specimens. We combined bioinformatics analyses and luciferase reporter assay to determine the relationship between miR-429 and Bcl-2 in GBM cells. Cell survival upon temozolomide treatment was analyzed in a CCK assay. Cell apoptosis was measured by fluorescein isothiocyanate (FITC) Annexin V apoptosis detection assay. We found that miR-429 levels were significantly decreased and Bcl-2 levels were significantly increased in GBM specimens, compared to the paired adjacent non-tumor brain tissue. Moreover, the levels of miR-429 and Bcl-2 inversely correlated. Low-miR-429 subjects had an overall inferior survival, compared to high-miR-429 subjects. MiR-429 targeted the 3'-UTR of Bcl-2 mRNA to inhibit its translation. Overexpression of miR-429 inhibited Bcl-2-mediated cell survival against temozolomide-induced apoptosis, while depletion of miR-429 augmented it. Together, our data suggest that miR-429 suppression in GBM promotes Bcl-2-mediated cancer cell survival against chemotherapy-induced cell death. Re-expression of miR-429 levels in GBM cells may improve the outcome of chemotherapy.

YT521 promotes metastases of endometrial cancer by differential splicing of vascular endothelial growth factor A

The malignancy of endometrial carcinoma (EC) largely results from its high invasive feature. The regulation of the mRNA splicing of vascular endothelial growth factor A (VEGF-A) is critical for EC-associated cancer vascularization and invasion. Recently, we have reported that poorly prognostic EC had high levels of YT521, a newly defined RNA splicing protein. However, whether YT521 may similarly regulate the splicing of VEGF-A in EC is unknown. Here, we showed that EC specimens contained significantly higher levels of YT521, compared to the adjacent non-tumor endometrial tissue. Higher levels of YT521 were detected in EC specimens with metastases. High-YT521 EC is associated with poor patient survival. In order to examine whether YT521 may regulate VEGF-A mRNA splicing in EC, we transfected an EC cell line HEC-1A with different doses of YT521 mimics. We found that YT521 dose-dependently increased the ratio of VEGF-165 vs VEGF-121 at both mRNA and protein level, suggesting that YT521 may promote VEGF-A mRNA splicing to favor a VEGF-165 isoform. Moreover, the increases in the ratio of VEGF-165 vs VEGF-121 by YT521 overexpression resulted in increases in EC cell invasion, while decreases in the ratio of VEGF-165 vs VEGF-121 by YT521 depletion resulted in decreases in EC cell invasion in a transwell cell migration assay. Further, overexpression of VEGF-165, but not overexpression of VEGF-121, increased EC cell invasiveness. Finally, a strong correlation was detected between the ratio of VEGF-165 vs VEGF-121 and the levels of YT521 in EC specimens. Together, these data suggest that YT521 may promote EC metastases by regulating mRNA splicing of VEGF-A.

High VEGF-D and Low MMP-2 Serum Levels Predict Nodal-Positive Disease in Invasive Bladder Cancer

Background

To investigate stromal variables including angiogenesis, lymphangiogenesis, and matrix metalloproteinase (MMP) in the serum of patients with urothelial carcinoma of the bladder (UCB) and to evaluate their association with histopathological characteristics and clinical outcome.

Material/Methods

Protein levels of vascular endothelial growth factors-A, -C, -D (VEGF-A/-C/-D), their receptors- VEGF-R2 and -R3 (VEGF-R2/-R3), and matrix metalloproteinases 2, -3, and -7 (MMP-2, MMP-3, MMP-7) were quantified in the blood serum samples of 71 patients with UCB before radical cystectomy (RC). Samples of patients with non-invasive UCB or no history of UCB were investigated as controls (n=20). Protein levels in the serum were measured using a flow cytometric cytokine assay.

Results

A positive association for VEGF-D (p<0.001) and an inverse association for MMP-2 (p=0.017) were observed in patients with positive lymph node (LN) status at the time of RC. VEGF-A (p<0.001), VEGF-C (p<0.001), MMP-2 (p<0.001), and MMP-7 (p=0.005) serum levels were different in serum of patients with invasive UCB compared with non-invasive UCB or healthy individuals. None of the serum markers were associated with disease progression.

Conclusions

High VEGF-D and low MMP-2 serum levels predict LN metastasis in patients with UCB at the time of RC. VEGF-A, VEGF-C, MMP-2, and MMP-7 serum levels varied significantly between invasive and non-invasive disease as well as in comparison with healthy individuals. Clinical implementation of these marker serum measurements may be valuable to select high-risk patients with more invasive or nodal-positive disease.

Ginsenoside Rh2 inhibits invasiveness of glioblastoma through modulation of VEGF-A

The malignancy of glioblastoma multiforme (GBM) is largely due to its local invasion and the presence of the tumor in the relatively restrained region in the brain. Hence, effective prevention of the cancer cell invasion is substantially critical for controlling the growth and deterioration of GBM. We have recently reported the role of ginsenoside Rh2 (GRh2) in suppressing the growth of GBM through EGFR/PI3k/Akt/mTor signaling pathways. Here, we further showed that GRh2 efficiently inhibited the cancer vascularization in vivo. In vitro, GRh2 dose-dependently inhibited the protein, but not messenger RNA (mRNA) of vascular endothelial growth factor A (VEGF-A) in GBM cells. We then examined the underlying mechanisms and found that GRh2 increased the levels of miR-497, which bound to 3'UTR of VEGF-A mRNA to inhibit its translation. Together, our data demonstrate a previously unappreciated role for GRh2 in inhibition of GBM-associated cancer vascularization, which may contribute to the effects of GRh2 on suppression of GBM cancer growth and invasion.

Ginsenoside Rh2 inhibits metastasis of glioblastoma multiforme through Akt-regulated MMP13

Glioblastoma multiforme (GBM) is the most malignant type of primary brain tumor. Although the growth of the tumor cells in a relatively closed space may partially account for its malignancy, highly invasive nature of glioblastoma cells has been suggested to be the main reason for the failure of current therapeutic approaches. Ginsenoside Rh2 (GRh2) has recently been shown to significantly suppress the growth and survival of GBM through inhibiting epidermal growth factor receptor signaling, whereas its effects on the invasion and metastasis have not been examined. Here, we showed that GRh2 dose-dependently decreased GBM cell invasiveness in both scratch wound healing assay and Transwell cell migration assay. Moreover, the inhibitory effects of GRh2 on cell migration seemed to be conducted through decreased expression of matrix metalloproteinase (MMP)-13. Furthermore, using specific inhibitors, we found that GRh2 inhibited MMP13 through PI3k/Akt signaling pathway. Finally, high MMP13 levels were detected in GBM specimen from the patients. Together, these data suggest that GRh2 may suppress GBM migration through inhibiting Akt-mediated MMP13 activation. Thus, our data highlight a previous unappreciated role for GRh2 in suppressing GBM cell metastasis.

Ginsenoside Rh2 inhibits growth of glioblastoma multiforme through mTor

Being the most malignant primary brain tumor in humans, glioblastoma multiforme (GBM) has a fairly poor patient survival after current combined treatment with chemotherapy, radiation, and surgery. Ginsenoside Rh2 (GRh2) has been reported to have a therapeutic effect on some tumors, and we recently reported its inhibitory effect on GBM growth in vitro and in vivo, possibly through an epidermal growth factor receptor (EGFR) signaling pathway. Here, using specific inhibitors, we found that the activation of EGFR signaling promoted GBM growth through PI3k/Akt/mTor signaling pathways. Moreover, GRh2 efficiently inhibited activation of this pathway at the receptor level. Together with our previous findings, these data suggest that GRh2 may suppress GBM growth through its competition with EGFR ligands for binding to the EGFR, and binding to EGFR by GRh2 does not lead to receptor phosphorylation. Thus, our data highlight a previous unappreciated role for GRh2 to inhibit EGFR signaling. GRh2 thus appears to be a promising therapy for cancers that require EGFR signaling to growth.

The effect of ASK1 on vascular permeability and edema formation in cerebral ischemia

Apoptosis signal-regulating kinase-1 (ASK1) is the mitogen-activated protein kinase kinase kinase (MAPKKK) and participates in the various central nervous system (CNS) signaling pathways. In cerebral ischemia, vascular permeability in the brain is an important issue because regulation failure of it results in edema formation and blood-brain barrier (BBB) disruption. To determine the role of ASK1 on vascular permeability and edema formation following cerebral ischemia, we first investigated ASK1-related gene expression using microarray analyses of ischemic brain tissue. We then measured protein levels of ASK1 and vascular endothelial growth factor (VEGF) in brain endothelial cells after hypoxia injury. We also examined protein expression of ASK1 and VEGF, edema formation, and morphological alteration through cresyl violet staining in ischemic brain tissue using ASK1-small interference RNA (ASK1-siRNA). Finally, immunohistochemistry was performed to examine VEGF and aquaporin-1 (AQP-1) expression in ischemic brain injury. Based on our findings, we propose that ASK1 is a regulating factor of vascular permeability and edema formation in cerebral ischemia.