Suppression of uPA and uPAR attenuates angiogenin mediated angiogenesis in endothelial and glioblastoma cell lines

Multicompartment duct platform to study epithelial-endothelial crosstalk associated with lung adenocarcinoma

Previous lung-on-chip devices have facilitated significant advances in our understanding of lung biology and pathology. Here, we describe a novel lung-on-a-chip model in which human induced pluripotent stem cell-derived alveolar epithelial type II cells (iAT2s) form polarized duct-like lumens alongside engineered perfused vessels lined with human umbilical vein endothelium, all within a 3D, physiologically relevant microenvironment. Using this model, we investigated the morphologic and signaling consequences of the KRASG12D mutation, a commonly identified oncogene in human lung adenocarcinoma (LUAD). We show that expression of the mutant KRASG12D isoform in iAT2s leads to a hyperproliferative response and morphologic dysregulation in the epithelial monolayer. Interestingly, the mutant epithelia also drive an angiogenic response in the adjacent vasculature that is mediated by enhanced secretion of the pro-angiogenic factor soluble uPAR. These results demonstrate the functionality of a multi-cellular in vitro platform capable of modeling mutation-specific behavioral and signaling changes associated with lung adenocarcinoma.

The role of PIWI-interacting RNA in naringin pro-angiogenesis by targeting HUVECs

Angiogenesis is a biological process in which resting endothelial cells start proliferating, migrating and forming new blood vessels. Angiogenesis is particularly important in the repair of bone tissue defects. Naringin (NG) is the main active monomeric component of traditional Chinese medicine, which has various biological activities, such as anti-osteoporosis, anti-inflammatory, blood activation and microcirculation improvement. At present, the mechanism of naringin in the process of angiogenesis is not clear. PIWI protein-interacting RNA (piRNA) is a small noncoding RNA (sncRNA) that has the functions of regulating protein synthesis, regulating the structure of chromatin and the genome, stabilizing mRNA and others. Several studies have demonstrated that piRNAs can mediate the angiogenesis process. Whether naringin can interfere with the process of angiogenesis by regulating piRNAs and related target genes deserves further exploration. Thus, the purpose of this study was to validate the potential angiogenic and bone regeneration properties and related mechanisms of naringin both in vivo and in vitro.

Treatment of Ovarian Hyperstimulation Syndrome in a Mouse Model by Cannabidiol, an Angiogenesis Pathway Inhibitor

Studies suggest that ovarian hyperstimulation syndrome (OHSS) can be treated by reducing the level of vascular endothelial growth factor (VEGF). However, due to the side effects of commercially available VEGF-reducing drugs, they can be ruled out as a suitable treatment for OHSS; therefore, researchers are looking for new medications to treat OHSS. This study is aimed at investigating the effects of cannabidiol (CBD) in an OHSS model and to evaluate its efficacy in modulating the angiogenesis pathway and VEGF gene expression. For this purpose, 32 female mice were randomly divided into four groups (eight mice per group): control group, group 2 with OHSS induction, group 3 receiving 32 nmol of dimethyl sulfoxide after OHSS induction, and group 4 receiving 30 mg/kg of CBD after OHSS induction. The animals' body weight, ovarian weight, vascular permeability (VP), and ovarian follicle count were measured, and the levels of VEGF gene and protein expression in the peritoneal fluid were assessed. Based on the results, CBD decreased the body and ovarian weights, VP, and corpus luteum number compared to the OHSS group (p < 0.05). The peritoneal VEGF gene and protein expression levels reduced in the CBD group compared to the OHSS group (p < 0.05). Also, CBD caused OHSS alleviation by suppressing VEGF expression and VP. Overall, CBD downregulated VEGF gene expression and improved VP in OHSS.

Characterization and Function of the Interaction of Angiogenin With Alpha-Actinin 2

Angiogenin (ANG) is the first human tumor-derived angiogenic protein, which can promote angiogenesis and tumor growth. In a previous study, we identified alpha-actinin 2 (ACTN2), a cytoskeletal protein, as a direct interacting protein with angiogenin. However, the interaction between ANG and ACTN2 was not characterized in detail, which may provide information on the molecular mechanisms of ANG functions. In this study, we mapped the accurate binding domain and sites in ANG and ACTN2, respectively. In ANG, the residues from 83 to 105 are the smallest motif that can bind to ACTN2. We then use site mutation analysis to identify the precise binding sites of ANG in the interaction and found that the 101st residue arginine (R101) represents the critical residue involved in the ANG–ACTN2 interaction. In ACTN2, the residues from 383 to 632, containing two spectrin domains in the middle of the rod structure of ACTN2, play an important role in the interaction. Furthermore, we validated the interaction of ACTN2-383–632 to ANG by glutathione-S-transferase (GST) pull-down assay. In functional analysis, overexpressed ACTN2-383–632 could impair tumor cell motility observably, including cell migration and invasion. Meanwhile, ACTN2-383–632 overexpression inhibited tumor cell proliferation and survival as well. These data suggest that an excess expression of ACTN2 segment ACTN2-383–632 can inhibit tumor cell motility and proliferation by interfering with the interaction between ANG and ACTN2, which provides a potential mechanism of ANG action in tumor growth and metastasis.

Urokinase Receptor uPAR Downregulation in Neuroblastoma Leads to Dormancy, Chemoresistance and Metastasis

Simple Summary

uPAR is a membrane receptor that contributes to extracellular matrix remodeling and controls cellular adhesion, proliferation, survival, and migration. We demonstrate that the initially high uPAR expression predicts poor survival in neuroblastoma. However, relapsed neuroblastomas have a significantly decreased uPAR expression. uPAR downregulation in neuroblastoma cells leads to dormancy and resistance to chemotherapeutic drugs. In mice, low uPAR-expressing neuroblastoma cells formed smaller primary tumors but more frequent metastasis.

Abstract

uPAR is a membrane receptor that binds extracellular protease urokinase, contributes to matrix remodeling and plays a crucial role in cellular adhesion, proliferation, survival, and migration. uPAR overexpression in tumor cells promotes mitogenesis, opening a prospective avenue for targeted therapy. However, uPAR targeting in cancer has potential risks. We have recently shown that uPAR downregulation in neuroblastoma promotes epithelial-mesenchymal transition (EMT), potentially associated with metastasis and chemoresistance. We used data mining to evaluate the role of uPAR expression in primary and relapsed human neuroblastomas. To model the decreased uPAR expression, we targeted uPAR using CRISPR/Cas9 and shRNA in neuroblastoma Neuro2a cells and evaluated their chemosensitivity in vitro as well as tumor growth and metastasis in vivo. We demonstrate that the initially high PLAUR expression predicts poor survival in human neuroblastoma. However, relapsed neuroblastomas have a significantly decreased PLAUR expression. uPAR targeting in neuroblastoma Neuro2a cells leads to p38 activation and an increased p21 expression (suggesting a dormant phenotype). The dormancy in neuroblastoma cells can be triggered by the disruption of uPAR-integrin interaction. uPAR-deficient cells are less sensitive to cisplatin and doxorubicin treatment and exhibit lower p53 activation. Finally, low uPAR-expressing Neuro2a cells formed smaller primary tumors, but more frequent metastasis in mice. To the best of our knowledge, this is the first study revealing the pathological role of dormant uPAR-deficient cancer cells having a chemoresistant and motile phenotype.

Update on Novel Targeted Therapy for Pleural Organization and Fibrosis

Pleural injury and subsequent loculation is characterized by acute injury, sustained inflammation and, when severe, pathologic tissue reorganization. While fibrin deposition is a normal part of the injury response, disordered fibrin turnover can promote pleural loculation and, when unresolved, fibrosis of the affected area. Within this review, we present a brief discussion of the current IPFT therapies, including scuPA, for the treatment of pathologic fibrin deposition and empyema. We also discuss endogenously expressed PAI-1 and how it may affect the efficacy of IPFT therapies. We further delineate the role of pleural mesothelial cells in the progression of pleural injury and subsequent pleural remodeling resulting from matrix deposition. We also describe how pleural mesothelial cells promote pleural fibrosis as myofibroblasts via mesomesenchymal transition. Finally, we discuss novel therapeutic targets which focus on blocking and/or reversing the myofibroblast differentiation of pleural mesothelial cells for the treatment of pleural fibrosis.

Prognostic Significance and Gene Co-Expression Network of PLAU and PLAUR in Gliomas

The urokinase-type plasminogen activator(PLAU) and its receptor PLAUR participate in a series of cell physiological activities on the extracellular surface. Abnormal expression of PLAU and PLAUR is associated with tumorigenesis. This study aims to evaluate the prognostic value of PLAU/PLAUR transcription expression in glioma and to explore how they affect the generation and progression of glioma. In this study, online databases are applied, such as Oncomine, GEPIA, CGGA, cBioPortal, and LinkedOmics. Overexpression of PLAU/PLAUR was found to be significantly associated with clinical variables including age, tumor type, WHO grade, histology, IDH-1 mutation, and 1p19q status. PLAU and PLAUR had a high correlation in transcriptional expression levels. High expression of PLAU and PLAUR predicted a poor prognosis in primary glioma and recurrent glioma patients, especially in lower grade gliomas. Cox regression analysis indicated that high expression of PLAU and PLAUR were independent prognostic factors for shorter overall survival in glioma patients. In gene co-expression network analysis PLAU and PLAUR and their co-expression genes were found to be involved in inflammatory activities and tumor-related signaling pathways. In conclusion, PLAU and PLAUR could be promising prognostic biomarkers and potential therapeutic targets of glioma patients.

TGF-β regulation of the uPA/uPAR axis modulates mesothelial-mesenchymal transition (MesoMT)

Pleural fibrosis (PF) is a chronic and progressive lung disease which affects approximately 30,000 people per year in the United States. Injury and sustained inflammation of the pleural space can result in PF, restricting lung expansion and impairing oxygen exchange. During the progression of pleural injury, normal pleural mesothelial cells (PMCs) undergo a transition, termed mesothelial mesenchymal transition (MesoMT). While multiple components of the fibrinolytic pathway have been investigated in pleural remodeling and PF, the role of the urokinase type plasminogen activator receptor (uPAR) is unknown. We found that uPAR is robustly expressed by pleural mesothelial cells in PF. Downregulation of uPAR by siRNA blocked TGF-β mediated MesoMT. TGF-β was also found to significantly induce uPA expression in PMCs undergoing MesoMT. Like uPAR, uPA downregulation blocked TGF-β mediated MesoMT. Further, uPAR is critical for uPA mediated MesoMT. LRP1 downregulation likewise blunted TGF-β mediated MesoMT. These findings are consistent with in vivo analyses, which showed that uPAR knockout mice were protected from S. pneumoniae-mediated decrements in lung function and restriction. Histological assessments of pleural fibrosis including pleural thickening and α-SMA expression were likewise reduced in uPAR knockout mice compared to WT mice. These studies strongly support the concept that uPAR targeting strategies could be beneficial for the treatment of PF.

Reduced Graphene Oxides Modulate the Expression of Cell Receptors and Voltage-Dependent Ion Channel Genes of Glioblastoma Multiforme

The development of nanotechnology based on graphene and its derivatives has aroused great scientific interest because of their unusual properties. Graphene (GN) and its derivatives, such as reduced graphene oxide (rGO), exhibit antitumor effects on glioblastoma multiforme (GBM) cells in vitro. The antitumor activity of rGO with different contents of oxygen-containing functional groups and GN was compared. Using FTIR (fourier transform infrared) analysis, the content of individual functional groups (GN/exfoliation (ExF), rGO/thermal (Term), rGO/ammonium thiosulphate (ATS), and rGO/ thiourea dioxide (TUD)) was determined. Cell membrane damage, as well as changes in the cell membrane potential, was analyzed. Additionally, the gene expression of voltage-dependent ion channels (clcn3, clcn6, cacna1b, cacna1d, nalcn, kcne4, kcnj10, and kcnb1) and extracellular receptors was determined. A reduction in the potential of the U87 glioma cell membrane was observed after treatment with rGO/ATS and rGO/TUD flakes. Moreover, it was also demonstrated that major changes in the expression of voltage-dependent ion channel genes were observed in clcn3, nalcn, and kcne4 after treatment with rGO/ATS and rGO/TUD flakes. Furthermore, the GN/ExF, rGO/ATS, and rGO/TUD flakes significantly reduced the expression of extracellular receptors (uPar, CD105) in U87 glioblastoma cells. In conclusion, the cytotoxic mechanism of rGO flakes may depend on the presence and types of oxygen-containing functional groups, which are more abundant in rGO compared to GN.

Podocin and uPAR are good biomarkers in cases of Focal and segmental glomerulosclerosis in pediatric renal biopsies

There are controversies whether Minimal Change Disease (MCD) and Focal and Segmental Glomerulosclerosis (FSGS) are distinct glomerular lesions or different manifestations within the same spectrum of diseases. The uPAR (urokinase-type plasminogen activator receptor) and some slit diaphragm proteins may be altered in FSGS glomeruli and may function as biomarkers of the disease in renal biopsies. Thus, this study aims to evaluate the diagnostic potential of uPAR and glomerular proteins for differentiation between MCD and FSGS in renal pediatric biopsy. Renal biopsies from 50 children between 2 and 18 years old were selected, with diagnosis of MCD (n = 29) and FSGS (n = 21). Control group consisted of pediatric autopsies (n = 15) from patients younger than 18 years old, with no evidences of renal dysfunction. In situ expressions of WT1, nephrin, podocin and uPAR were evaluated by immunoperoxidase technique. Renal biopsy of patients with MCD and FSGS expressed fewer WT1 (p≤0.0001, F = 19.35) and nephrin (p<0.0001; H = 21.54) than patients in the control group. FSGS patients expressed fewer podocin than control (p<0.0359, H = 6.655). FSGS cases expressed more uPAR than each of control and MCD (p = 0.0019; H = 12.57) and there was a positive and significant correlation between nephrin and podocin (p = 0.0026, rS = 0.6502) in these cases. Podocin had sensitivity of 73.3% and specificity of 86.7% (p = 0.0068) and uPAR had sensitivity of 78.9% and specificity of 73.3% (p = 0.0040) for diagnosis of FSGS patients. The main limitation of the study is the limited number of cases due to the difficulty in performing biopsy in pediatric patients. Podocin and uPAR are good markers for FSGS and differentiate these cases from MCD, reinforcing the theory of distinct glomerular diseases. These findings suggest that podocin and uPAR can be used as biomarkers in the routine analysis of renal biopsies in cases of podocytopathies when the lesion (sclerosis) is not sampled.

Identification of Crucial Candidate Genes and Pathways in Glioblastoma Multiform by Bioinformatics Analysis

The present study aimed to investigate the molecular mechanisms underlying glioblastoma multiform (GBM) and its biomarkers. The differentially expressed genes (DEGs) were diagnosed using the limma software package. The ToppGene (ToppFun) was used to perform pathway and Gene Ontology (GO) enrichment analysis of the DEGs. Protein-protein interaction (PPI) networks, extracted modules, miRNA-target genes regulatory network and TF-target genes regulatory network were used to obtain insight into the actions of DEGs. Survival analysis for DEGs was carried out. A total of 590 DEGs, including 243 up regulated and 347 down regulated genes, were diagnosed between scrambled shRNA expression and Lin7A knock down. The up-regulated genes were enriched in ribosome, mitochondrial translation termination, translation, and peptide biosynthetic process. The down-regulated genes were enriched in focal adhesion, VEGFR3 signaling in lymphatic endothelium, extracellular matrix organization, and extracellular matrix. The current study screened the genes in the PPI network, extracted modules, miRNA-target genes regulatory network, and TF-target genes regulatory network with higher degrees as hub genes, which included NPM1, CUL4A, YIPF1, SHC1, AKT1, VLDLR, RPL14, P3H2, DTNA, FAM126B, RPL34, and MYL5. Survival analysis indicated that the high expression of RPL36A and MRPL35 were predicting longer survival of GBM, while high expression of AP1S1 and AKAP12 were predicting shorter survival of GBM. High expression of RPL36A and AP1S1 were associated with pathogenesis of GBM, while low expression of ALPL was associated with pathogenesis of GBM. In conclusion, the current study diagnosed DEGs between scrambled shRNA expression and Lin7A knock down samples, which could improve our understanding of the molecular mechanisms in the progression of GBM, and these crucial as well as new diagnostic markers might be used as therapeutic targets for GBM.

The Role of Fibrinolytic Regulators in Vascular Dysfunction of Systemic Sclerosis

Systemic sclerosis (SSc) is a connective tissue disease of autoimmune origin characterized by vascular dysfunction and extensive fibrosis of the skin and visceral organs. Vascular dysfunction is caused by endothelial cell (EC) apoptosis, defective angiogenesis, defective vasculogenesis, endothelial-to-mesenchymal transition (EndoMT), and coagulation abnormalities, and exacerbates the disease. Fibrinolytic regulators, such as plasminogen (Plg), plasmin, α2-antiplasmin (α2AP), tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA) and its receptor (uPAR), plasminogen activator inhibitor 1 (PAI-1), and angiostatin, are considered to play an important role in the maintenance of endothelial homeostasis, and are associated with the endothelial dysfunction of SSc. This review considers the roles of fibrinolytic factors in vascular dysfunction of SSc.

Angiogenin Upregulation Independently Predicts Unfavorable Overall Survival in Proneural Subtype of Glioblastoma

Objective:

Angiogenin is a small protein that exerts potent stimulating effects on angiogenesis. In this study, we aimed to examine the expression of angiogenin in different subtypes of glioblastoma and estimated its independent prognostic value.

Methods:

The genomic and survival data from The Cancer Genome Atlas-glioblastoma were extracted for a secondary study. Results The expression of angiogenin was upregulated in glioblastoma tissues and varied significantly in different subtypes. Although the proneural subtype had the lowest angiogenin expression, high angiogenin expression was associated with significantly worse overall survival. However, this association was not observed in other subtypes. By performing univariate and multivariate analysis using Cox regression model, we observed that high angiogenin expression was an independent indicator of shorter overall survival in proneural glioblastoma (hazard ratio: 1.669, 95% confidence interval: 1.033-2.696, P = .036), after adjustment of age, gender, isocitrate dehydrogenase 1 mutation, temozolomide chemotherapy and radiation therapy. In addition, we also observed a correlation between elevated angiogenin expression and the hypomethylated status of its DNA. The hypermethylation group had significantly better overall survival.

Conclusions:

Angiogenin upregulation might serve as a biomarker for unfavorable overall survival in the proneural subtype of glioblastoma.

Cellular prion protein and γ-synuclein overexpression in LS 174T colorectal cancer cell drives endothelial proliferation-to-differentiation switch

Background

Tumor-induced angiogenesis is an imperative event in pledging new vasculature for tumor metastasis. Since overexpression of neuronal proteins gamma-synuclein (γ-Syn) and cellular prion protein (PrP^C) is always detected in advanced stages of cancer diseases which involve metastasis, this study aimed to investigate whether γ-Syn or PrP^C overexpression in colorectal adenocarcinoma, LS 174T cells affects angiogenesis of endothelial cells, EA.hy 926 (EA).

Methods

EA cells were treated with conditioned media (CM) of LS 174T-γ-Syn or LS 174T-PrP, and their proliferation, invasion, migration, adhesion and ability to form angiogenic tubes were assessed using a range of biological assays. To investigate plausible background mechanisms in conferring the properties of EA cells above, nitrite oxide (NO) levels were measured and the expression of angiogenesis-related factors was assessed using a human angiogenesis antibody array.

Results

EA proliferation was significantly inhibited by LS 174T-PrP CM whereas its telomerase activity was reduced by CM of LS 174T-γ-Syn or LS 174T-PrP, as compared to EA incubated with LS 174T CM. Besides, LS 174T-γ-Syn CM or LS 174T-PrP CM inhibited EA invasion and migration in Boyden chamber assay. Furthermore, LS 174T-γ-Syn CM significantly inhibited EA migration in scratch wound assay. Gelatin zymography revealed reduced secretion of MMP-2 and MMP-9 by EA treated with LS 174T-γ-Syn CM or LS 174T-PrP CM. In addition, cell adhesion assay showed lesser LS 174T-γ-Syn or LS 174T-PrP cells adhered onto EA, as compared to LS 174T. In tube formation assay, LS 174T-γ-Syn CM or LS 174T-PrP CM induced EA tube formation. Increased NO secretion by EA treated with LS 174T-γ-Syn CM or LS 174T-PrP CM was also detected. Lastly, decreased expression of pro-angiogenic factors like CXCL16, IGFBP-2 and amphiregulin in LS 174T-γ-Syn CM or LS 174T-PrP CM was detected using the angiogenesis antibody array.

Discussion

These results suggest that overexpression of γ-Syn or PrP^C could possibly be involved in colorectal cancer-induced angiogenesis by inducing an endothelial proliferation-differentiation switch. NO could be the main factor in governing this switch, and modulation on the secretion patterns of angiogenesis-related proteins could be the strategy of colorectal cancer cells overexpressing γ-Syn or PrP^C in ensuring this transition.

Ribonuclease 5 facilitates corneal endothelial wound healing via activation of PI3-kinase/Akt pathway

To maintain corneal transparency, corneal endothelial cells (CECs) exert a pump function against aqueous inflow. However, human CECs are arrested in the G₁-phase and non-proliferative in vivo. Thus, treatment of corneal endothelial decompensation is limited to corneal transplantation, and grafts are vulnerable to immune rejection. Here, we show that ribonuclease (RNase) 5 is more highly expressed in normal human CECs compared to decompensated tissues. Furthermore, RNase 5 up-regulated survival of CECs and accelerated corneal endothelial wound healing in an in vitro wound of human CECs and an in vivo cryo-damaged rabbit model. RNase 5 treatment rapidly induced accumulation of cytoplasmic RNase 5 into the nucleus, and activated PI3-kinase/Akt pathway in human CECs. Moreover, inhibition of nuclear translocation of RNase 5 using neomycin reversed RNase 5-induced Akt activation. As a potential strategy for proliferation enhancement, RNase 5 increased the population of 5-bromo-2′-deoxyuridine (BrdU)-incorporated proliferating CECs with concomitant PI3-kinase/Akt activation, especially in CECs deprived of contact-inhibition. Specifically, RNase 5 suppressed p27 and up-regulated cyclin D1, D3, and E by activating PI3-kinase/Akt in CECs to initiate cell cycle progression. Together, our data indicate that RNase 5 facilitates corneal endothelial wound healing, and identify RNase 5 as a novel target for therapeutic exploitation.

Three decades of research on angiogenin: a review and perspective

As a member of the vertebrate-specific secreted ribonucleases, angiogenin (ANG) was first isolated and identified solely by its ability to induce new blood vessel formation, and now, it has been recognized to play important roles in various physiological and pathological processes through regulating cell proliferation, survival, migration, invasion, and/or differentiation. ANG exhibits very weak ribonucleolytic activity that is critical for its biological functions, and exerts its functions through activating different signaling transduction pathways in different target cells. A series of recent studies have indicated that ANG contributes to cellular nucleic acid metabolism. Here, we comprehensively review the results of studies regarding the structure, mechanism, and function of ANG over the past three decades. Moreover, current problems and future research directions of ANG are discussed. The understanding of the function and mechanism of ANG in a wide context will help to better delineate its roles in diseases, especially in cancer and neurodegenerative diseases.

Combined EGFR- and notch inhibition display additive inhibitory effect on glioblastoma cell viability and glioblastoma-induced endothelial cell sprouting in vitro

Background

For Glioblastoma (GBM) patients, a number of anti-neoplastic strategies using specifically targeting drugs have been tested; however, the effects on survival have been limited. One explanation could be treatment resistance due to redundant signaling pathways, which substantiates the need for combination therapies. In GBM, both the epidermal growth factor receptor (EGFR) and the notch signaling pathways are often deregulated and linked to cellular growth, invasion and angiogenesis. Several studies have confirmed cross-talk and co-dependence of these pathways. Therefore, this study aimed at testing a combination treatment strategy using inhibitors targeting the notch and EGFR pathways.

Methods

For evaluation of cell viability a standard MTT assay was used. Western blotting (WB) and Q-RT-PCR were employed in order to assess the protein- and mRNA expression levels, respectively. In order to determine angiogenic processes, we used an endothelial spheroid sprouting assay. For assessment of secreted VEGF from GBM cells we performed a VEGF-quantikine ELISA.

Results

GBM cells were confirmed to express EGFR and Notch and to have the capacity to induce endothelial cell sprouting. Inhibition of EGFR and Notch signaling was achieved using either Iressa (gefitinib) or the gamma-secretase inhibitor DAPT. Our data showed that DAPT combined with Iressa treatment displayed increased inhibitory effect on cell viability and abrogated expression and activation of major pro-survival pathways. Similarly, the combinational treatment significantly increased abrogation of GBM-induced endothelial cell sprouting suggesting reduced GBM angiogenesis.

Conclusion

This study finds that simultaneous targeting of notch and EGFR signaling leads to enhanced inhibitory effects on GBM-induced angiogenesis and cell viability, thereby stressing the importance of further evaluation of this targeting approach in a clinical setting.

Electronic supplementary material

The online version of this article (doi:10.1186/s12935-016-0309-2) contains supplementary material, which is available to authorized users.

Significance of the urokinase-type plasminogen activator and its receptor in the progression of focal segmental glomerulosclerosis in clinical and mouse models

Background

suPAR biomarker generally considered a pathogenic factor in FSGS. However, studies have been published that dispute this conclusion. The current study was designed to investigate the roles of uPA and suPAR in FSGS in clinical and mouse models.

Methods

Clinical subjects including those with biopsy-proven FSGS and MCD were enrolled. To verify the role of uPA in FSGS, Adriamycin was used to induce FSGS in uPA knockout (uPA^−/−) and BALB/c (WT) mice. Proteinuria and suPAR, the cleaved/intact forms of the circulating suPAR, and possible proteases involving cleavage of the suPAR were also studied.

Results

FSGS clinical cases presented significantly higher serum levels of suPAR and Cr and lower serum levels of uPA. In the mice model, the uPA^−/− group exhibited faster disease progression and worsening proteinuria than the WT group. In addition, the uPA^−/− group had higher plasma suPAR levels, glomerular cell apoptosis, and dysregulation of the Th1/Th2 balance. In an analysis of suPAR variants in FSGS, both the intact and cleaved forms of the suPAR were higher in clinical subjects and the mouse model. However, the process of suPAR cleavage was not mediated by enzymatic activities of the uPA, elastase, or cathepsin G.

Conclusions

A deficiency of uPA accelerated the progression of Adriamycin-induced mouse FSGS model. Decrease of serum uPA levels may be an indicator of the progression of FSGS in clinical subjects and animal models.

The Matricellular Receptor LRP1 Forms an Interface for Signaling and Endocytosis in Modulation of the Extracellular Tumor Environment

The membrane protein low-density lipoprotein receptor related-protein 1 (LRP1) has been attributed a role in cancer. However, its presumably often indirect involvement is far from understood. LRP1 has both endocytic and signaling activities. As a matricellular receptor it is involved in regulation, mostly by clearing, of various extracellular matrix degrading enzymes including matrix metalloproteinases, serine proteases, protease inhibitor complexes, and the endoglycosidase heparanase. Furthermore, by binding extracellular ligands including growth factors and subsequent intracellular interaction with scaffolding and adaptor proteins it is involved in regulation of various signaling cascades. LRP1 expression levels are often downregulated in cancer and some studies consider low LRP1 levels a poor prognostic factor. On the contrary, upregulation in brain cancers has been noted and clinical trials explore the use of LRP1 as cargo receptor to deliver cytotoxic agents. This mini-review focuses on LRP1's role in tumor growth and metastasis especially by modulation of the extracellular tumor environment. In relation to this role its diagnostic, prognostic and therapeutic potential will be discussed.

Angiogenic Potential and Secretome of Human Apical Papilla Mesenchymal Stem Cells in Various Stress Microenvironments

Stem cells from the apical papilla (SCAP) of human adult teeth are considered an accessible source of cells with angiogenic properties. The aims of this study were to investigate the endothelial transdifferentiation of SCAP, the secretion of pro- and antiangiogenic factors from SCAP, and the paracrine effects of SCAP when exposed to environmental stress to stimulate tissue damage. SCAP were exposed to serum deprivation (SD), glucose deprivation (GD), and oxygen deprivation/hypoxia (OD) conditions, individually or in combination. Endothelial transdifferentiation was evaluated by in vitro capillary-like formation assays, real-time polymerase chain reaction, western blot, and flow cytometric analyses of angiogenesis-related markers; secretome by antibody arrays and enzyme-linked immunosorbent assays (ELISA); and paracrine impact on human umbilical vein endothelial cells (HUVECs) by in vitro transwell migration and capillary-like formation assays. The short-term exposure of SCAP to glucose/oxygen deprivation (GOD) in the presence, but mainly in deprivation, of serum (SGOD) elicited a proangiogenesis effect indicated by expression of angiogenesis-related genes involved in vascular endothelial growth factor (VEGF)/VEGFR and angiopoietins/Tie pathways. This effect was unachievable under SD in normoxia, suggesting that the critical microenvironmental condition inducing rapid endothelial shift of SCAP is the combination of SGOD. Interestingly, SCAP showed high adaptability to these adverse conditions, retaining cell viability and acquiring a capillary-forming phenotype. SCAP secreted higher numbers and amounts of pro- (angiogenin, IGFBP-3, VEGF) and lower amounts of antiangiogenic factors (serpin-E1, TIMP-1, TSP-1) under SGOD compared with SOD or SD alone. Finally, secretome obtained under SGOD was most effective in inducing migration and capillary-like formation by HUVECs. These data provide new evidence on the microenvironmental factors favoring endothelial transdifferentiation of SCAP, uncovering the molecular mechanisms regulating their fate. They also validate the angiogenic properties of their secretome giving insights into preconditioning strategies enhancing their therapeutic potential.

Immunohistochemical Detection of Urokinase Plasminogen Activator and Urokinase Plasminogen Activator Receptor in Canine Vascular Endothelial Tumours

Immunohistochemistry was used to assess the expression of urokinase plasminogen activator (uPA) and uPA receptor (uPAR) in 57 canine primary haemangiosarcomas (HSAs), 26 canine cutaneous haemangiomas (HAs) and in control sections of canine cutaneous granulation tissue. The correlation between uPA/uPAR expression and the Ki67 labelling index (LI) was estimated in the HSA and HA tissues. uPA was expressed by 73.2% and 75.0% of splenic HSAs and non-splenic HSAs, respectively. All HSA tissues tested expressed uPAR. Expression of both molecules was significantly higher in HSAs than in cutaneous HAs (3.8% for uPA and 30.7% for uPAR). The average Ki67 LI of the uPA(+)/uPAR(+) HSAs was significantly higher than that of uPA(-)/uPAR(+) HSAs and HA tissues (mean ± SDs 32.8 ± 15.3, 15.2 ± 7.2 and 2.1 ± 0.7, respectively; P <0.05). These results suggest that uPA and uPAR play a significant role in the malignant proliferation of canine HSA, regardless of the primary origin of the tumour.

The Ketogenic Diet Alters the Hypoxic Response and Affects Expression of Proteins Associated with Angiogenesis, Invasive Potential and Vascular Permeability in a Mouse Glioma Model

Background

The successful treatment of malignant gliomas remains a challenge despite the current standard of care, which consists of surgery, radiation and temozolomide. Advances in the survival of brain cancer patients require the design of new therapeutic approaches that take advantage of common phenotypes such as the altered metabolism found in cancer cells. It has therefore been postulated that the high-fat, low-carbohydrate, adequate protein ketogenic diet (KD) may be useful in the treatment of brain tumors. We have demonstrated that the KD enhances survival and potentiates standard therapy in a mouse model of malignant glioma, yet the mechanisms are not fully understood.

Methods

To explore the effects of the KD on various aspects of tumor growth and progression, we used the immunocompetent, syngeneic GL261-Luc2 mouse model of malignant glioma.

Results

Tumors from animals maintained on KD showed reduced expression of the hypoxia marker carbonic anhydrase 9, hypoxia inducible factor 1-alpha, and decreased activation of nuclear factor kappa B. Additionally, tumors from animals maintained on KD had reduced tumor microvasculature and decreased expression of vascular endothelial growth factor receptor 2, matrix metalloproteinase-2 and vimentin. Peritumoral edema was significantly reduced in animals fed the KD and protein analyses showed altered expression of zona occludens-1 and aquaporin-4.

Conclusions

The KD directly or indirectly alters the expression of several proteins involved in malignant progression and may be a useful tool for the treatment of gliomas.

MT1-MMP silencing by an shRNA-armed glioma-targeted conditionally replicative adenovirus (CRAd) improves its anti-glioma efficacy in vitro and in vivo

MMP14 (MT1-MMP) is a cell membrane-associated proteinase of the extracellular matrix, whose biological roles vary from angiogenesis to cell proliferation and survival. We recently found a direct correlation between MMP14 expression levels in brain tumors of glioma patients and the disease progression. By using gene silencing as an experimental approach we found that MMP14 knockdown decreases production of pro-angiogenic factors such as VEGF and IL8 and thereby suppresses angiogenesis in glioma tumors. Although the clinical relevance of MMP14 down-regulation and its possible implications for glioma therapy in humans remain unclear, we observed a significant improvement in animal survival upon down-regulation of MMP14 in murine intracranial glioma xenografts infected with MMP14 shRNA-expressing CRAd. We further found that down-regulation of MMP14 in gliomas by combinational treatment with CRAd-S-5/3 and Marimastat, a chemical inhibitor of metalloproteinases, augments suppression of pro-angiogenic factors, caused by the replication-competent adenovirus. We also demonstrated that delivery of MMP14-targeting shRNA by a fiber-modified adenoviral vector to the glioma cells effectively suppresses their proliferation in vitro and in vivo. Thus our data indicate that inhibition of MMP14 expression in tumors in combination with glioma virotherapy could be effectively utilized to suppress angiogenesis and neovascularization of glioma tumors by decreasing production of pro-angiogenic factors.

Critical multiple angiogenic factors secreted by glioblastoma stem-like cells underline the need for combinatorial anti-angiogenic therapeutic strategies

Glioblastomas are the most frequent adult primary brain tumors that still remain fatal despite major clinical efforts. As in other solid tumors, populations of glioblastoma stem-like cells (GSCs) endowed with tumor initiating and therapeutic resistance properties have been identified. Glioblastomas are highly vascularized tumors resulting in a rich dialog between GSCs and endothelial cells. In one direction, endothelial cells and their secreted proteins are able to sustain GSC properties while, in turn, GSCs can promote neoangiogenesis, modulate endothelial cell functions and may even transdifferentiate into endothelial cells. Accordingly, targeting tumor vasculature seems a promising issue despite incomplete and transient results obtained from anti-vascular endothelial growth factor therapeutic trials. Recent findings of novel GSC-secreted molecules with pro-angiogenic properties (Semaphorin 3A, hepatoma-derived growth factor) open the path to the design of a concerted attack of glioblastoma vasculature that could overcome the development of resistance to single-targeted therapies while keeping away the toxicity of the treatments.

Adipose-derived mesenchymal stromal cells from aged patients with coronary artery disease keep mesenchymal stromal cell properties but exhibit characteristics of aging and have impaired angiogenic potential

Tissue regeneration is impaired in aged individuals. Adipose-derived mesenchymal stromal cells (ADSCs), a promising source for cell therapy, were shown to secrete various angiogenic factors and improve vascularization of ischemic tissues. We analyzed how patient age affected the angiogenic properties of ADSCs. ADSCs were isolated from subcutaneous fat tissue of patients with coronary artery disease (CAD; n = 64, 43-77 years old) and without CAD (n = 31, 2-82 years old). ADSC phenotype characterized by flow cytometry was CD90(+)/CD73(+)/CD105(+)/CD45(-)/CD31(-) for all samples, and these cells were capable of adipogenic and osteogenic differentiation. ADSCs from aged patients had shorter telomeres (quantitative reverse transcription polymerase chain reaction) and a tendency to attenuated telomerase activity. ADSC-conditioned media (ADSC-CM) stimulated capillary-like tube formation by endothelial cells (EA.hy926), and this effect significantly decreased with the age of patients both with and without CAD. Angiogenic factors (vascular endothelial growth factor, placental growth factor, hepatocyte growth factor, angiopoetin-1, and angiogenin) in ADSC-CM measured by enzyme-linked immunosorbent assay significantly decreased with patient age, whereas levels of antiangiogenic factors thrombospondin-1 and endostatin did not. Expression of angiogenic factors in ADSCs did not change with patient age (real-time polymerase chain reaction); however, gene expression of factors related to extracellular proteolysis (urokinase and its receptor, plasminogen activator inhibitor-1) and urokinase-type plasminogen activator receptor surface expression increased in ADSCs from aged patients with CAD. ADSCs from aged patients both with and without CAD acquire aging characteristics, and their angiogenic potential declines because of decreasing proangiogenic factor secretion. This could restrict the effectiveness of autologous cell therapy with ADSCs in aged patients.

Tumor-associated soluble uPAR-directed endothelial cell motility and tumor angiogenesis

The expression of urokinase-type plasminogen activator (uPA) receptor (uPAR) correlates with the malignant phenotype of various cancers. The soluble form of uPAR (s-uPAR) is present in the circulation of cancer patients, but the role of s-uPAR in endothelial cell migration is poorly understood. Therefore, we examined the role of tumor-associated s-uPAR on endothelial cell motility and angiogenesis. Here, we present evidence that tumor-associated s-uPAR augments the migration of human umbilical vein endothelial cells (HUVECs). When grown on tumor-conditioned medium, the membrane fraction of HUVECs had increased localization of s-uPAR onto its cell membrane. Colocalization studies for GM1 ganglioside receptor and uPAR further demonstrated s-uPAR recruitment onto lipid rafts of HUVECs. Immunoblot analysis for uPAR in lipid raft fractions confirmed s-uPAR recruiting onto HUVECs' membrane. Further, s-uPAR induced Rac1-mediated cell migration while either function-blocking uPAR antibodies or dominant-negative mutant Rac1 expression in HUVECs-mitigated s-uPAR-enhanced cell migration. In addition, orthotopic implantation of uPAR-overexpressing cells resulted in a significant increase in circulating s-uPAR in blood serum and invasive nature of tumor and tumor vasculature in mice. Collectively, this data provide insight into tumor-associated s-uPAR-directed migration of endothelial cells and its subsequent influence on tumor angiogenesis.

Cannabidiol inhibits angiogenesis by multiple mechanisms

BACKGROUND AND PURPOSE

Several studies have demonstrated anti-proliferative and pro-apoptotic actions of cannabinoids on various tumours, together with their anti-angiogenic properties. The non-psychoactive cannabinoid cannabidiol (CBD) effectively inhibits the growth of different types of tumours in vitro and in vivo and down-regulates some pro-angiogenic signals produced by glioma cells. As its anti-angiogenic properties have not been thoroughly investigated to date, and given its very favourable pharmacological and toxicological profile, here, we evaluated the ability of CBD to modulate tumour angiogenesis.

EXPERIMENTAL APPROACH

Firstly, we evaluated the effect of CBD on human umbilical vein endothelial cell (HUVEC) proliferation and viability - through [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and FACS analysis - and in vitro motility - both in a classical Boyden chamber test and in a wound-healing assay. We next investigated CBD effects on different angiogenesis-related proteins released by HUVECs, using an angiogenesis array kit and an ELISA directed at MMP2. Then we evaluated its effects on in vitro angiogenesis in treated HUVECs invading a Matrigel layer and in HUVEC spheroids embedded into collagen gels, and further characterized its effects in vivo using a Matrigel sponge model of angiogenesis in C57/BL6 mice.

KEY RESULTS

CBD induced HUVEC cytostasis without inducing apoptosis, inhibited HUVEC migration, invasion and sprouting in vitro, and angiogenesis in vivo in Matrigel sponges. These effects were associated with the down-modulation of several angiogenesis-related molecules.

CONCLUSIONS AND IMPLICATIONS

This study reveals that CBD inhibits angiogenesis by multiple mechanisms. Its dual effect on both tumour and endothelial cells supports the hypothesis that CBD has potential as an effective agent in cancer therapy.

Overexpression of CIAPIN1 inhibited pancreatic cancer cell proliferation and was associated with good prognosis in pancreatic cancer

Cytokine-induced antiapoptotic molecule (CIAPIN1), a newly identified apoptosis inhibitor, has been found to participate in the process of proliferation and tumorigenicity for several cancers. The aim of this study was to evaluate the prognostic value of CIAPIN1 in pancreatic cancer and to probe its function in pancreatic carcinogenesis. We found that CIAPIN1 protein was absent or reduced in pancreatic cancer cell lines. There was also a loss or decrease in CIAPIN1 expression in 118 cases of pancreatic cancer tissues as compared with that in 82 cases of normal pancreatic tissues. In a Cox proportional hazards model, CIAPIN1 expression independently predicted better survival (P<0.0001). Adenoviral-mediated restoration of CIAPIN1 expression greatly repressed the proliferation of pancreatic cancer cell in vitro and suppressed the tumorigenicity of pancreatic cancer cell in Balb/c nude mice. Our data also revealed that inhibition of pancreatic cancer cells proliferation by enforcing CIAPIN1 expression at least partly through delaying cell cycle progression and inducing cell apoptosis. In summary, our work revealed a novel function of CIAPIN1, which might possibly be used as an independent prognostic factor and a potential therapeutic target for pancreatic cancer.

uPA and uPAR shRNA inhibit angiogenesis via enhanced secretion of SVEGFR1 independent of GM-CSF but dependent on TIMP-1 in endothelial and glioblastoma cells

The uPA/uPAR system is known to play a critical role in angiogenesis of glioblastoma. Previously, we have shown that shRNA against uPA and uPAR attenuates angiogenesis by blocking nuclear translocation of angiogenin, inhibition of angiopoietin/Tie2 signaling, and regulating several other pro-angiogenic, angiostatic and anti-angiogenic molecules. Further analysis revealed that GM-CSF, a pleiotropic cytokine, was significantly inhibited in U87MG and 4910 co-cultures with endothelial cells transfected with shRNA against uPA and uPAR. The role of the uPA/uPAR system in this process is not completely understood. Analysis of tumor conditioned medium of U87MG, 4910 and HMECs transfected with shRNA against uPA or uPAR alone or in combination (pU2) revealed inhibition of GM-CSF-enhanced secretion of SVEGFR1 as shown by Western blotting and ELISA. Moreover, phosphorylation of JAK2 and STAT5, the downstream effectors of GM-CSF signaling, was also inhibited in all three cell lines. Phosphorylation at Tyr 166 position of the GM-CSFRβ subunit, the signal activating subunit of the GM-CSF receptor, was inhibited in HMEC, U87MG and 4910 cells. Further analysis revealed that shRNA against uPA and/or uPAR increased secretion of TIMP-1, which is known to enhance SVEGFR1 secretion in endothelial cells. Moreover, addition of purified uPA (with and without GM-CSF) activated JAK2/STAT5 signaling in HMEC. Exogenous addition of SVEGFR1 to pU2 tumor conditioned medium enhanced inhibition of VEGF-induced endothelial capillary tube formation as assessed by an in vitro angiogenesis assay. To determine the significance of these events in vivo, nude mice with pre-established tumors treated with shRNA against uPA and/or uPAR showed decreased levels of GM-CSF and increased levels of SVEGFR1 and TIMP-1 when compared with controls. Enhanced secretion of SVEGFR1 by puPA, puPAR and pU2 in endothelial and GBM cells was mediated indirectly by MMP-7 and augmented by ectodomain shedding of VEGFr1 by tyrosine phosphorylation at the 1213 position. Taken together, these results suggest that the uPA/uPAR system could prove beneficial as an indirect target for inhibition of angiogenesis in glioblastoma.

Specific knockdown of uPA/uPAR attenuates invasion in glioblastoma cells and xenografts by inhibition of cleavage and trafficking of Notch -1 receptor

BACKGROUND

uPA/uPAR is a multifunctional system that is over expressed in many cancers and plays a critical role in glioblastoma (GBM) invasion. Previous studies from our lab have also shown that uPA/uPAR down regulation inhibits cancer cell invasion in SNB 19 GBM cells.

METHODS

As Notch 1 is known to be over expressed and promotes invasion in glioblastoma, we therefore tested our hypothesis of whether down regulation of uPA/uPAR, singly or in tandem, attenuates GBM invasion via Notch 1 receptor. Targeted down regulation of uPA/uPAR, either singly or simultaneously, inhibited the anchorage independent growth of U251MG and GBM xenograft cell lines 4910 and 5310 as assessed by soft agar colony formation assay. Expression of all four Notch receptors was confirmed in GBM tissue array analysis by immunohistochemistry.

RESULTS

Down regulation of uPA/uPAR, either singly or simultaneously, in U251 MG and tumor xenografts inhibited the cleavage of the Notch receptor between the Gly 1743 and Val 1744 positions, thereby suggesting inhibition of activated cytosolic fragment-related Notch gene transcription. Morphological analysis confirmed inhibition of NICD when U251 MG cells were treated with puPA, puPAR or pU2. uPA/uPAR down regulation inhibited Notch 1 mRNA in all three examined cell lines. uPA/uPAR shRNA down regulated nuclear activation of NF-κB subunits and phosphorylation of AKT/mTOR pathway in U251 MG and GBM xenografts. puPA down regulated NICD and HES induced phosphorylation of AKT/ERK and NF-κB. Down regulation of Notch 1 using siRNA inhibited uPA activity as shown by fibrinogen zymography. It also decreased uPA expression levels as shown by western blotting. Exogenous addition of uPA activated Notch 1 in uPAR antisense U251 MG cells and also in uPAR antisense cells transfected with siRNA against Delta and Jagged. The Notch 1 receptor co-localized with LAMP-1, a marker for lysosomes in uPA, uPAR and U2, down regulated U251 MG cells which probably indicates inhibition of Notch 1 receptor trafficking in GBM cells. Notch 1 expression was significantly inhibited in puPA- and pU2-treated pre-established intracranial tumors in mice.

CONCLUSIONS

Overall our results show that down regulation of uPA/uPAR, either singly or simultaneously, could be an effective approach to attenuate Notch 1 receptor cleavage, signaling and endosomal trafficking in U251MG cells and xenografts, and ultimately inhibiting GBM invasion.

VEGF is essential for hypoxia-inducible factor-mediated neovascularization but dispensable for endothelial sprouting

Although our understanding of the molecular regulation of adult neovascularization has advanced tremendously, vascular-targeted therapies for tissue ischemia remain suboptimal. The master regulatory transcription factors of the hypoxia-inducible factor (HIF) family are attractive therapeutic targets because they coordinately up-regulate multiple genes controlling neovascularization. Here, we used an inducible model of epithelial HIF-1 activation, the TetON-HIF-1 mouse, to test the requirement for VEGF in HIF-1 mediated neovascularization. TetON-HIF-1, K14-Cre, and VEGF(flox/flox) alleles were combined to create TetON-HIF-1:VEGF(Δ) mice to activate HIF-1 and its target genes in adult basal keratinocytes in the absence of concomitant VEGF. HIF-1 induction failed to produce neovascularization in TetON-HIF-1:VEGF(Δ) mice despite robust up-regulation of multiple proangiogenic HIF targets, including PlGF, adrenomedullin, angiogenin, and PAI-1. In contrast, endothelial sprouting was preserved, enhanced, and more persistent, consistent with marked reduction in Dll4-Notch-1 signaling. Optical-resolution photoacoustic microscopy, which provides noninvasive, label-free, high resolution, and wide-field vascular imaging, revealed the absence of both capillary expansion and arteriovenous remodeling in serially imaged individual TetON-HIF-1:VEGF(Δ) mice. Impaired TetON-HIF-1:VEGF(Δ) neovascularization could be partially rescued by 12-O-tetradecanoylphorbol-13-acetate skin treatment. These data suggest that therapeutic angiogenesis for ischemic cardiovascular disease may require treatment with both HIF-1 and VEGF.

Cathepsin B and uPAR knockdown inhibits tumor-induced angiogenesis by modulating VEGF expression in glioma

Angiogenesis, which is the process of sprouting of new blood vessels from pre-existing vessels, is vital for tumor progression. Proteolytic remodeling of extracellular matrix is a key event in vessel sprouting during angiogenesis. Urokinase type plasminogen activator receptor (uPAR) and cathepsin B are both known to be overexpressed and implicated in tumor angiogenesis. In the present study, we observed that knockdown of uPAR and cathepsin B using puPAR (pU), pCathepsin B (pC), and a bicistronic construct of uPAR and cathepsin B (pCU) caused significant inhibition of angiogenesis by disrupting the janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway-dependent expression of vascular endothelial growth factor (VEGF). Further, transcriptional suppression of uPAR and cathepsin B inhibited tumor-induced migration, proliferation of endothelial cells and decreased tumor-promoted expression of VEGF receptor-2, Rac1, gp91phox, cyclin D1, cyclin dependent kinase 4 and p-Rb in human dermal microvascular endothelial cell. Furthermore, U251 and SNB19 xenograft tissue sections from nude mice treated with pCU showed reduced expression of VEGF and CD31, which is a blood vessel visualization marker. Overall, results revealed that knockdown of uPAR and cathepsin B inhibited tumor-induced angiogenesis by disrupting the JAK/STAT pathway-dependent expression of VEGF. These data provide new insight in characterizing the pathways involved in the angiogenic cascade and for the identification of novel target proteins for use in therapeutic intervention for gliomas.

Suppression of uPA and uPAR blocks radiation-induced MCP-1 mediated recruitment of endothelial cells in meningioma

Chemokines play a vital role in recruiting various cell types in the process of tissue repair. Radiation, a major therapeutic modality in cancer treatment, has been described to induce inflammatory response that might lead to the expression of several chemokines. In the present study, we investigated the mechanism of monocyte chemoattractant protein-1 (MCP-1) induction by radiation in meningioma cell lines and the paracrine effect on human microvascular endothelial cells (HMEC). After radiation, meningioma cell lines (IOMM Lee and SF-3061) showed an increased expression of MCP-1. In addition, irradiated meningioma cancer cell conditioned medium (CM) showed an increased ability to attract HMEC and to stimulate MCP-1-induced protein (MCPIP), VEGF and angiogenin expression in HMEC. This chemotactic activity and angiogenic stimulator effect on HMEC were almost abrogated by depleting MCP-1 from the irradiated cancer cell CM. Further, inhibition of either ERK activation/expression or NF-κB nuclear translocation hindered radiation-induced MCP-1 expression in both meningioma cell lines. Further, supplementing cancer cells with exogenous ATF-uPA (with and without radiation) activated ERK phosphorylation, nuclear translocation of the NF-κB p65 sub-unit (Rel-A), and MCP-1 expression. Downregulation of uPA and uPAR, simultaneously by transfecting the cancer cells with bi-cistronic siRNA-expressing plasmid (pU) inhibited radiation-induced ERK activation, nuclear translocation of Rel-A, NF-κB DNA binding activity, and MCP-1 expression. In addition, pU-transfected cancer cells (with or without radiation) reduced radiation-induced MCP-1 and blocked the recruitment of other cell types during the inflammatory process induced by radiation both in in vitro and in vivo conditions.