Antisense MMP-9 RNA inhibits malignant glioma cell growth in vitro and in vivo

Local Delivery of Minocycline and Vorinostat Targets the Tumor Microenvironment to Inhibit the Recurrence of Glioma

Background

Postoperative recurrence is the main reason for poor clinical outcomes in glioma patients, so preventing tumor recurrence is crucial in the management of gliomas.

Methods

In this study, the expression of matrix metalloproteinases (MMPs) in normal tissues was detected via RNA-seq analysis. Glioma cases from the public databases (The Cancer Genome Atlas (TCGA), the Chinese Glioma Genome Atlas (CGGA)) were included in this study. The hydrogel contains minocycline (Mino) and vorinostat (Vor) (G/Mino+Vor) was formed under 365 nm when the photoinitiator was added. High-performance liquid chromatography (HPLC) was used to assess the release of drugs in the G/Mino+Vor hydrogel. An MTT assay was used to explore the biosecurity of GelMA. Immunohistochemistry, ELISA, and TUNEL assays were used to demonstrate the antitumor effect of the G/Mino+Vor hydrogel.

Results

We successfully developed a G/Mino+Vor hydrogel. The experiments in vitro and in vivo confirmed the MMPs-responsive delivery of minocycline and vorinostat in hydrogel and the anti-glioma effect on an incomplete tumor operation model, which indicated that the G/Mino+Vor hydrogel effectively inhibited the recurrence of glioma after surgery.

Conclusion

In summary, the G/Mino+Vor hydrogel could continuously release drugs and improve the therapy effects against recurrent glioma.

Extracellular proteolysis in glioblastoma progression and therapeutics

Gliomas encompass highly invasive primary central nervous system (CNS) tumours of glial cell origin with an often-poor clinical prognosis. Of all gliomas, glioblastoma is the most aggressive form of primary brain cancer. Current treatments in glioblastoma are insufficient due to the invasive nature of brain tumour cells, which typically results in local tumour recurrence following treatment. The latter represents the most important cause of mortality in glioblastoma and underscores the necessity for an in-depth understanding of the underlying mechanisms. Interestingly, increased synthesis and secretion of several proteolytic enzymes within the tumour microenvironment, such as matrix metalloproteinases, lysosomal proteases, cathepsins and kallikreins for extracellular-matrix component degradation may play a major role in the aforementioned glioblastoma invasion mechanisms. These proteolytic networks are key players in establishing and maintaining a tumour microenvironment that promotes tumour cell survival, proliferation, and migration. Indeed, the targeted inhibition of these proteolytic enzymes has been a promisingly useful therapeutic strategy for glioblastoma management in both preclinical and clinical development. We hereby summarize current advances on the biology of the glioblastoma tumour microenvironment, with a particular emphasis on the role of proteolytic enzyme families in glioblastoma invasion and progression, as well as on their subsequent prognostic value as biomarkers and their therapeutic targeting in the era of precision medicine.

Repression of Septin9 and Septin2 suppresses tumor growth of human glioblastoma cells

Glioblastoma (GBM) is the most common primary malignancy of the central nervous system (CNS) with <10% 5-year survival rate. The growth and invasion of GBM cells into normal brain make the resection and treatment difficult. A better understanding of the biology of GBM cells is crucial to the targeted therapies for the disease. In this study, we identified Septin9 (SEPT9) and Septin2 (SEPT2) as GBM-related genes through integrated multi-omics analysis across independent transcriptomic and proteomic studies. Further studies revealed that expression of SEPT9 and SEPT2 was elevated in glioma tissues and cell lines (A172, U87-MG). Knockdown of SEPT9 and SEPT2 in A172/U87-MG was able to inhibit GBM cell proliferation and arrest cell cycle progression in the S phase in a synergistic mechanism. Moreover, suppression of SEPT9 and SEPT2 decreased the GBM cell invasive capability and significantly impaired the growth of glioma xenografts in nude mice. Furthermore, the decrease in GBM cell growth caused by SEPT9 and SEPT2 RNAi appears to involve two parallel signaling pathway including the p53/p21 axis and MEK/ERK activation. Together, our integration of multi-omics analysis has revealed previously unrecognized synergistic role of SEPT9 and SEPT2 in GBM, and provided novel insights into the targeted therapy of GBM.

Long Non-coding RNA LINC00339 Stimulates Glioma Vasculogenic Mimicry Formation by Regulating the miR-539-5p/TWIST1/MMPs Axis

Glioma is recognized as a highly angiogenic malignant brain tumor. Vasculogenic mimicry (VM) greatly restricts the therapeutic effect of anti-angiogenic tumor therapy for glioma patients. However, the molecular mechanisms of VM formation in glioma remain unclear. Here, we demonstrated that LINC00339 was upregulated in glioma tissue as well as in glioma cell lines. The expression of LINC00339 in glioma tissues was positively correlated with glioma VM formation. Knockdown of LINC00339 inhibited glioma cell proliferation, migration, invasion, and tube formation, meanwhile downregulating the expression of VM-related molecular MMP-2 and MMP-14. Furthermore, knockdown of LINC00339 significantly increased the expression of miR-539-5p. Both bioinformatics and luciferase reporter assay revealed that LINC00339 regulated the above effects via binding to miR-539-5p. Besides, overexpression of miR-539-5p resulted in decreased expression of TWIST1, a transcription factor known to play an oncogenic role in glioma and identified as a direct target of miR-539-5p. TWIST1 upregulated the promoter activities of MMP-2 and MMP-14. The in vivo study showed that nude mice carrying tumors with knockdown of LINC00339 and overexpression of miR-539-5p exhibited the smallest tumor volume through inhibiting VM formation. In conclusion, LINC00339 may be used as a novel therapeutic target for VM formation in glioma.

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.

Icaritin inhibits the invasion and epithelial-to-mesenchymal transition of glioblastoma cells by targeting EMMPRIN via PTEN/AKt/HIF-1α signalling

Icaritin, a hydrolytic product of icariin from the Epimedium genus, exerts anti-tumour effects on a variety of tumour cell types, mainly by inhibiting cell proliferation and inducing apoptosis. However, little is known about the role of icaritin in cancer invasion and epithelial-to-mesenchymal transition (EMT). In the present study, the glioblastoma (GBM) cell line U87MG was used as a model to investigate the effects of icaritin on the invasion and EMT of cancer cells. The results showed that icaritin significantly inhibited the invasion and EMT of GBM cells by targeting extracellular matrix metalloproteinase (EMMPRIN). Furthermore, the findings strongly indicate that the modulatory effect of icaritin on EMMPRIN is mediated via the PTEN/Akt/HIF-1α signalling pathway. The data provide the first experimental evidence of the inhibitory effect of icaritin on cancer cell invasion and EMT, thus highlighting the potential of icaritin to be employed as a promising anti-cancer agent in the treatment of GBM.

The effects of CD147 on the cell proliferation, apoptosis, invasion, and angiogenesis in glioma

To analyze the effects of extracellular matrix metalloproteinase inducer (CD147) on glioma proliferation, apoptosis, invasion, and angiogenesis. Tissue samples were obtained from 101 glioma cases while normal brain tissues were obtained from 30 brain injury cases. Immunohistochemical assay was performed to detect the expressions of CD147, CD34, and VEGF in tissue samples. QRT-PCR was performed to detect the relative expression of CD147 mRNA in human glioma cell lines. CD147 siRNA was transfected into glioma cell line U251. Cell proliferation, apoptosis, invasion, and angiogenesis were tested by MTT, flow cytometry, Transwell assay, and vasculogenic mimicry assay, respectively. Expressions of relative proteins were analyzed with western blot. CD147 was positively expressed with the percentage of 0, 37.5, 44.8, 67.9, and 85.7 % in normal tissues and glioma tissues with WHO grades I-IV, respectively, and the scores of MVDand VEGF were associated with the expression of CD147. CD147 was significantly upregulated in the human glioma cell lines (P < 0.05). Downregulated the expression of CD147 suppressed cell proliferation, blocked cell cycle, induced apoptosis, inhibited cell invasion and angiogenesis in glioma cells in vitro. The expression of CD147 was significantly associated with WHO tumor grade and angiogenesis; silencing of CD147 contributed to inhibition of glioma proliferation, invasion, and angiogenesis. Our study provided firm evidence that CD 147 is a potential glioma target for anti-angiogenic therapies.

Caffeine suppresses the progression of human glioblastoma via cathepsin B and MAPK signaling pathway

Glioblastoma has aggressive proliferative and invasive properties. We investigated the effect of caffeine on the invasion and the anti-cancer effect in human glioblastomas. Caffeine reduced the invasion in U-87MG, GBM8401 and LN229 cells. Caffeine decreased mRNA, protein expression, and activity of cathepsin B. Besides, mRNA and protein expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) was upregulated by caffeine treatment, whereas matrix metalloproteinase-2 (MMP-2) was downregulated. The expression of Ki67, p-p38, phospforylated extracellular regulated protein kinases (p-ERK), and membranous integrin β1 and β3 was decreased by caffeine. The Rho-associated protein kinase (ROCK) inhibitor, Y27632, blocked the caffeine-mediated reduction of cathepsin B, phosphorylated focal adhesion kinase (p-FAK), and p-ERK, and invasion. Moreover, caffeine decreased the tumor size, cathepsin B and Ki67 expression in animal model. Caffeine reduced the invasion of glioma cells through ROCK-cathepsin B/FAK/ERK signaling pathway and tumor growth in orthotopic xenograft animal model, supporting the anti-cancer potential in glioma therapy.

MMP-9 in translation: from molecule to brain physiology, pathology, and therapy

Matrix metalloproteinase-9 (MMP-9) is a member of the metzincin family of mostly extracellularly operating proteases. Despite the fact that all of these enzymes might be target promiscuous, with largely overlapping catalogs of potential substrates, MMP-9 has recently emerged as a major and apparently unique player in brain physiology and pathology. The specificity of MMP-9 may arise from its very local and time-restricted actions, even when released in the brain from cells of various types, including neurons, glia, and leukocytes. In fact, the quantity of MMP-9 is very low in the naive brain, but it is markedly activated at the levels of enzymatic activity, protein abundance, and gene expression following various physiological stimuli and pathological insults. Neuronal MMP-9 participates in synaptic plasticity by controlling the shape of dendritic spines and function of excitatory synapses, thus playing a pivotal role in learning, memory, and cortical plasticity. When improperly unleashed, MMP-9 contributes to a large variety of brain disorders, including epilepsy, schizophrenia, autism spectrum disorder, brain injury, stroke, neurodegeneration, pain, brain tumors, etc. The foremost mechanism of action of MMP-9 in brain disorders appears to be its involvement in immune/inflammation responses that are related to the enzyme's ability to process and activate various cytokines and chemokines, as well as its contribution to blood-brain barrier disruption, facilitating the extravasation of leukocytes into brain parenchyma. However, another emerging possibility (i.e., the control of MMP-9 over synaptic plasticity) should not be neglected. The translational potential of MMP-9 has already been recognized in both the diagnosis and treatment domains. The most striking translational aspect may be the discovery of MMP-9 up-regulation in a mouse model of Fragile X syndrome, quickly followed by human studies and promising clinical trials that have sought to inhibit MMP-9. With regard to diagnosis, suggestions have been made to use MMP-9 alone or combined with tissue inhibitor of matrix metalloproteinase-1 or brain-derived neurotrophic factor as disease biomarkers. MMP-9, through cleavage of specific target proteins, plays a major role in synaptic plasticity and neuroinflammation, and by those virtues contributes to brain physiology and a host of neurological and psychiatric disorders. This article is part of the 60th Anniversary special issue.

Naringin inhibits the invasion and migration of human glioblastoma cell via downregulation of MMP-2 and MMP-9 expression and inactivation of p38 signaling pathway

Gliomas are the most common and malignant primary brain tumors. They are associated with a poor prognosis despite the availability of multiple therapeutic options. Naringin, a common dietary flavonoid abundantly present in fruits and vegetables, is believed to possess strong anti-proliferative and anti-cancer properties. However, there are no reports describing its effects on the invasion and migration of glioblastoma cell lines. Our results showed that the treatment of U251 glioma cell lines with different concentrations of naringin inhibited the invasion and migration of these cells. In addition, we revealed a decrease in the levels of matrix metalloproteinases (MMP-2) and (MMP-9) expression as well as proteinase activity in U251 glioma cells. In contrast, the expression of tissue inhibitor of metalloproteinases (TIMP-1) and (TIMP-2) was increased. Furthermore, naringin treatment decreased significantly the phosphorylated level of p38. Combined treatment with a p38 inhibitor (SB203580) resulted in the synergistic reduction of MMP-2 and MMP-9 expressions correlated with an increase of TIMP-1 and TIMP-2 expressions and the anti-invasive properties. However, p38 chemical activator (anisomycin) could block these effects produced by naringin, suggesting a direct downregulation of the p38 signaling pathway. These data suggest that naringin may have therapeutic potential for controlling invasiveness of malignant gliomas by inhibiting of p38 signal transduction pathways.

Down-regulation of cancer/testis antigen OY-TES-1 attenuates malignant behaviors of hepatocellular carcinoma cells in vitro

Cancer/testis (CT) antigens are normally expressed in testis and overexpressed in various tumor types. However, their biological function is largely unknown. OY-TES-1, one of cancer/testis (CT) antigens, is reported overexpression in hepatocellular carcinoma (HCC). And we assumed that OY-TES-1 contribute to oncogenesis and progression of HCC. In this study, we knocked down OY-TES-1 by small interference RNA (siRNA) in HCC cell lines (HepG2 and BEL-7404) to verify this assumption and evaluate its potential as therapeutic targets for HCC. We showed that down regulation of OY-TES-1 decreased cell growth, induced the G0/G1 arrest and apoptosis, and prevented migration and invasion in the two HCC cell lines. Further analysis revealed that down regulation of OY-TES-1 increased expression of apoptosis-regulated protein caspase-3, and decreased expression of cell cycle-regulated protein cyclin E, migration/invasion-regulated proteins MMP2 and MMP9. These findings may shed light on the gene therapy about the OY-TES-1 expression in HCC cells.

Osthole suppresses the proliferation and accelerates the apoptosis of human glioma cells via the upregulation of microRNA-16 and downregulation of MMP-9

Osthole (7-methoxy-8-isoamyl alkenyl coumarin) has been reported to exhibit marked anticancer effects on several types of cancer. The expression levels of matrix metalloproteinase-9 (MMP-9) are closely associated with the pathogenesis of glioma. Furthermore, it is reported that the upregulation of microRNA‑16 (miR‑16) by the MMP‑9 signaling pathway can restrain the proliferation of cancer cells. To examine whether osthole increases the anticancer effect on human glioma cells in the present study, the common glioma cell line, U87, was treated with osthole at concentrations of 0, 50, 100 and 200 µΜ. The effects of osthole on cell viability were determined using a 3‑(4,5‑dimethylthiazol‑2‑thiazolyl)‑2,5‑diphenyl‑tetrazolium bromide assay. The rate of cellular apoptosis was analyzed by measuring the activity of caspase‑3 and using flow cytometry. The expression of MMP‑9 was determined using gelatin zymography assays and the expression of miR‑16 was determined using reverse transcription‑quantitative polymerase chain reaction. The results demonstrated that osthole significantly suppressed the proliferation and accelerated the apoptosis of the U87 cells. Furthermore, increased expression levels of miR‑16 and reduced protein expression levels of MMP‑9 were found in the U87 cells. In addition, miR‑16 was found to regulate the expression of MMP‑9 in the U87 cells through transfection of miR‑16 precursor and anti‑miR‑16 into the U87 cells. In conclusion, these observations indicated that osthole suppressed the proliferation and accelerated the apoptosis of human glioma cells through upregulation of the expression of miR‑16 and downregulation of the expression of MMP-9.

Fingolimod alters inflammatory mediators and vascular permeability in intracerebral hemorrhage

Intracerebral hemorrhage (ICH) leads to high rates of death and disability. The pronounced inflammatory reactions that rapidly follow ICH contribute to disease progression. Our recent clinical trial demonstrated that oral administration of an immune modulator fingolimod restrained secondary injury derived from initial hematoma, but the mechanisms remain unknown. In this study, we aim to investigate the effects of fingolimod on inflammatory mediators and vascular permeability in the clinical trial of oral fingolimod for intracerebral hemorrhage (ICH). The results showed that fingolimod decreased the numbers of circulating CD4(+) T, CD8(+) T, CD19(+) B, NK, and NKT cells and they recovered quickly after the drug was stopped. The plasma ICAM level was decreased and IL-10 was increased by fingolimod. Interestingly, fingolimod protected vascular permeability as indicated by a decreased plasma level of MMP9 and the reduced rT1%. In conclusion, modulation of systemic inflammation by fingolimod demonstrates that it is an effective therapeutic agent for ICH. Fingolimod may prevent perihematomal edema enlargement by protecting vascular permeability.

Matrix Metalloproteinase-9/Neutrophil Gelatinase-Associated Lipocalin Complex Activity in Human Glioma Samples Predicts Tumor Presence and Clinical Prognosis

Matrix metalloproteinase-9/neutrophil gelatinase-associated lipocalin (MMP-9/NGAL) complex activity is elevated in brain tumors and may serve as a molecular marker for brain tumors. However, the relationship between MMP-9/NGAL activity in brain tumors and patient prognosis and treatment response remains unclear. Here, we compared the clinical characteristics of glioma patients with the MMP-9/NGAL activity measured in their respective tumor and urine samples. Using gelatin zymography assays, we found that MMP-9/NGAL activity was significantly increased in tumor tissues (TT) and preoperative urine samples (Preop-1d urine). Activity was reduced by seven days after surgery (Postop-1w urine) and elevated again in cases of tumor recurrence. The MMP-9/NGAL status correlated well with MRI-based tumor assessments. These findings suggest that MMP-9/NGAL activity could be a novel marker to detect gliomas and predict the clinical outcome of patients.

Epilysin is overexpressed in glioblastoma and related to clinical outcome of patients

As the newest identified member of the matrix metalloproteinase (MMP) family, the expression pattern and function of epilysin (MMP-28) are still not well understood. Although epilysin was found to play an evolutionarily conserved role in neural development, the expression and function of epilysin in malignant glioma are unknown. Therefore, the aim of the present study was to quantitatively evaluate the expression level of epilysin in glioblastoma (GBM) and its association with clinical outcome of patients. For this purpose, a total of 216 GBM specimens and 31 normal brain specimens were collected in the present study. Expression level of epilysin was determined by immunohistochemistry assay and immunoreactivity score system. MGMT promoter methylation and IDH1/2 mutation status in GBM were also evaluated. Results showed that the positive rate of epilysin staining in GBM was significantly elevated compared with that in normal brain. Positive epilysin staining was associated with low KPS score, unmethylated MGMT promoter and wild-type IDH. Kaplan-Meier analysis showed that patients with GBM of positive epilysin staining were more likely to have unfavorable overall survival. Multivariate analysis revealed that epilysin was an independent and significant prognostic marker of GBM. These results proved for the first time that epilysin expression was significantly elevated in GBM and can be potentially used to predict prognosis in patients with GBM.

Diversin is overexpressed in human gliomas and its depletion inhibits proliferation and invasion

Previous study indicated diversin overexpression in human cancers. However, its expression pattern in human gliomas and the molecular mechanisms of diversin on cancer progression have not been characterized. In the present study, diversin expression was investigated in 105 glioma specimens using immunohistochemistry. Negative staining was observed in normal glial cells, and positive staining was found in 33 out of 105 (31.4 %) glioma specimens. Diversin overexpression correlated with advanced tumor grade (p < 0.05). Small interfering RNA (siRNA) knockdown was performed in U87 and TG905 cell lines with high endogenous diversin expression. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony formation assay showed that diversin knockdown inhibited glioma cell growth. Matrigel invasion assay showed that diversin depletion inhibited cell invasion. In addition, messenger RNA (mRNA) and protein levels of matrix metallopeptidase 9 (MMP9) were downregulated after siRNA treatment. In conclusion, diversin is overexpressed in human glioma and regulates glioma cell proliferation and invasion, possibly through MMP9.

Glioma-associated microglial MMP9 expression is upregulated by TLR2 signaling and sensitive to minocycline

The invasiveness of malignant gliomas is one of the major obstacles in glioma therapy and the reason for the poor survival of patients. Glioma cells infiltrate into the brain parenchyma and thereby escape surgical resection. Glioma associated microglia/macrophages support glioma infiltration into the brain parenchyma by increased expression and activation of extracellular matrix degrading proteases such as matrix metalloprotease (MMP) 2, MMP9 and membrane-type 1 MMP. In this work we demonstrate that, MMP9 is predominantly expressed by glioma associated microglia/macrophages in mouse and human glioma tissue but not by the glioma cells. Supernatant from glioma cells induced the expression of MMP9 in cultured microglial cells. Using mice deficient for different Toll-like receptors we identified Toll-like receptor 2/6 as the signaling pathway for the glioma induced upregulation of microglial MMP9. Also in an experimental mouse glioma model, Toll-like receptor 2 deficiency attenuated the upregulation of microglial MMP9. Moreover, glioma supernatant triggered an upregulation of Toll-like receptor 2 expression in microglia. Both, the upregulation of MMP9 and Toll-like receptor 2 were attenuated by the antibiotic minocycline and a p38 mitogen-activated protein kinase antagonist in vitro. Minocycline also extended the survival rate of glioma bearing mice when given to the drinking water. Thus glioma cells change the phenotype of glioma associated microglia/macrophages in a complex fashion using Toll-like receptor 2 as an important signaling pathway and minocycline further proved to be a potential candidate for adjuvant glioma therapy.

Baicalein reduces the invasion of glioma cells via reducing the activity of p38 signaling pathway

Baicalein, one of the major flavonids in Scutellaria baicalensis, has historically been used in anti-inflammatory and anti-cancer therapies. However, the anti-metastatic effect and related mechanism(s) in glioma are still unclear. In this study, we thus utilized glioma cell lines U87MG and U251MG to explore the effect of baicalein. We found that administration of baicalein significantly inhibited migration and invasion of glioma cells. In addition, after treating with baicalein for 24 h, there was a decrease in the levels of matrix metalloproteinase-2 (MMP-2) and MMP-9 expression as well as proteinase activity in glioma cells. Conversely, the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2 was increased in a dose-dependent manner. Moreover, baicalein treatment significantly decreased the phosphorylated level of p38, but not ERK1/2, JNK1/2 and PI3K/Akt. Combined treatment with a p38 inhibitor (SB203580) and baicalein resulted in the synergistic reduction of MMP-2 and MMP-9 expression and then increase of TIMP-1 and TIMP-2 expression; and the invasive capabilities of U87MG cells were also inhibited. However, p38 chemical activator (anisomycin) could block these effects produced by baicalein, suggesting baicalein directly downregulate the p38 signaling pathway. In conclusion, baicalein inhibits glioma cells invasion and metastasis by reducing cell motility and migration via suppression of p38 signaling pathway, suggesting that baicalein is a potential therapeutic agent for glioma.

Prognostic significance of CD147 in patients with glioblastoma

CD147, also known as extracellular matrix metalloproteinase inducer, is a widely distributed cell surface glycoprotein that belongs to the immunoglobulin superfamily. CD147 has been proved to be enriched on the surface of many tumor cells, promoting tumor growth, invasion and metastasis by its stimulation effect on adjacent fibroblasts to produce matrix metalloproteinases. In this study, we aimed to explore the expression pattern of CD147 in glioblastoma (GBM) and investigate whether it could be used to assess subsequent prognosis of patients. For that, we recruited a total of 206 patients with pathologically confirmed GBM and 36 normal control brain tissue specimens. The expression of CD147 in GBM and normal tissues was investigated by immunohistochemistry assay. Genetic factors including MGMT and IDH1 mutation were also investigated to justify the prognostic significance of CD147. Results showed that CD147 expression was increased in GBM compared with that in normal tissues. Kaplan-Meier analysis showed that increased CD147 expression was associated with poor overall survival of patients with GBM. Moreover, Cox's proportional hazards model revealed that CD147 expression was an independent and significant prognostic marker of overall survival in GBM patients. These results proved that CD147 expression was relatively abundant in GBM and can be potentially used to predict prognosis and treatment response in GBM patients.

SPAG9 is overexpressed in human astrocytoma and promotes cell proliferation and invasion

Sperm-associated antigen 9 (SPAG9) is a recently characterized oncoprotein involved in the progression of several human malignancies. The present study aims to investigate the expression pattern and biological roles of SPAG9 protein in human astrocytoma. SPAG9 expression was analyzed in 105 astrocytoma specimens by immunohistochemistry. We observed negative staining in normal astrocytes and positive staining of SPAG9 in 63 out of 105 (60 %) astrocytoma samples. Overexpression of SPAG9 correlated with tumor grade (p < 0.001). Small interfering RNA knockdown was performed in U251 and U87 cell lines with relatively high SPAG9 expression. Using methylthiazolyldiphenyl-tetrazolium bromide assay and Matrigel invasion assay, we were able to show that SPAG9 depletion in astrocytoma cell lines inhibited cell proliferation and invasion in both cell lines. In addition, mRNA and protein levels of matrix metallopeptidase 9 (MMP9) were downregulated, while the levels of tissue inhibitor of metalloproteinase 1 (TIMP1) and TIMP2 were not changed, indicating that SPAG9 might regulate invasion through MMP9. In conclusion, SPAG9 serves as an important oncoprotein in human astrocytoma by regulating cell proliferation and invasion.