The Clinical Utility of Matrix Metalloproteinase 9 in Evaluating Pathological Grade and Prognosis of Glioma Patients: A Meta-Analysis

Biological significance and pathophysiological role of Matrix Metalloproteinases in the Central Nervous System

Matrix Metalloproteinases (MMPs), which are endopeptidase reliant on zinc, are low in embryonic tissues but increases in response to a variety of physiological stimulus and pathological stresses. Neuro-glial cells, endothelial cells, fibroblasts, and leucocytes secrete MMPs, which cleave extracellular matrix proteins in a time-dependent manner. MMPs affect synaptic plasticity and the development of short-term memory by controlling the size, shape, and excitatory synapses' function through the lateral diffusion of receptors. In addition, MMPs influence the Extracellular Matrix proteins in the Peri-Neuronal Net at the Neuro-glial interface, which aids in the establishment of long-term memory. Through modulating neuronal, and glial cells migration, differentiation, Neurogenesis, and survival, MMPs impact brain development in mammals. In adult brains, MMPs play a beneficial role in physiological plasticity, which includes learning, memory consolidation, social interaction, and complex behaviors, by proteolytically altering a wide variety of factors, including growth factors, cytokines, receptors, DNA repair enzymes, and matrix proteins. Additionally, stress, depression, addiction, hepatic encephalopathy, and stroke may all have negative effects on MMPs. In addition to their role in glioblastoma development, MMPs influence neurological diseases such as epilepsy, schizophrenia, autism spectrum disorder, brain damage, pain, neurodegeneration, and Alzheimer's and Parkinson's. To help shed light on the potential of MMPs as a therapeutic target for neurodegenerative diseases, this review summarizes their regulation, mode of action, and participation in brain physiological plasticity and pathological damage. Finally, by employing different MMP-based nanotools and inhibitors, MMPs may also be utilized to map the anatomical and functional connectome of the brain, analyze its secretome, and treat neurodegenerative illnesses.

Nanoparticle Drug Delivery System for Glioma and Its Efficacy Improvement Strategies: A Comprehensive Review

Gliomas are the most common tumor of the central nervous system. However, the presence of the brain barrier blocks the effective delivery of drugs and leads to the treatment failure of various drugs. The development of a nanoparticle drug delivery system (NDDS) can solve this problem. In this review, we summarized the brain barrier (including blood-brain barrier (BBB), blood-brain tumor barriers (BBTB), brain-cerebrospinal fluid barrier (BCB), and nose-to-brain barrier), NDDS of glioma (such as passive targeting systems, active targeting systems, and environmental responsive targeting systems), and NDDS efficacy improvement strategies and deficiencies. The research prospect of drug-targeted delivery systems for glioma is also discussed.

Syndecan-1 knockdown inhibits glioma cell proliferation and invasion by deregulating a c-src/FAK-associated signaling pathway

Recent studies have shown that increased syndecan-1 (SDC1) expression in human glioma is associated with higher tumor grades and poor prognoses, but its oncogenic functions and the underlying molecular mechanisms remain unknown. Here, we examined SDC1 expression in datasets from The Cancer Genome Atlas and the National Center for Biotechnology Information Gene Expression Omnibus. Elevated SDC1 expression in glioma was closely associated with increases in tumor progression and shorter survival. We also examined SDC1 expression and evaluated the effects of stable SDC1 knockdown in glioma cell lines. SDC1 knockdown attenuated proliferation and invasion by glioma cells and markedly decreased PCNA and MMP-9 mRNA and protein expression. In a xenograft model, SDC1 knockdown suppressed the tumorigenic effects of U87 cells in vivo. SDC1 knockdown decreased phosphorylation of the c-src/FAK complex and its downstream signaling molecules, Erk, Akt and p38 MAPK. These results suggest that SDC1 may be a novel therapeutic target in the treatment of glioma.

Regional specificity of matrix metalloproteinase-9 expression in the brain: voxel-level mapping in primary glioblastomas

AIM

To investigate the anatomical specificity of matrix metalloproteinase-9 (MMP-9) expression in glioblastomas by using voxel-based neuroimaging analysis.

MATERIALS AND METHODS

Clinical information and preoperative magnetic resonance images of 133 patients with glioblastomas were reviewed. Evaluation of MMP-9 expression was performed by using immunohistochemistry. Tumour lesions were segmented manually basing on the structural image of each patient, then registered to a standard brain atlas. Voxel-based regression analysis was subsequently performed to identify the specific brain regions that were associated with MMP-9 expression levels.

RESULTS

A significantly larger lesion volume of T2-hyperintensity was demonstrated in tumours with low MMP-9 expression compared to those with high MMP-9 expression (p=0.010). No significant difference was found in the lesion volumes of the contrast enhancement areas between the two groups (p=0.452). The major correlated cluster with high MMP-9 expression was identified in the right frontal lobe, while a cluster located at the posterior region of the right lateral ventricle was correlated with low MMP-9 expression.

CONCLUSION

Voxel-based statistical analysis revealed the anatomical specificity of MMP-9 expression levels in glioblastoma. The identified correlation between molecular biomarkers and anatomical distribution may increase our understanding of the biological characteristics of glioblastoma and provide new insight into the molecular subtypes of glioblastoma.

ADAM9 Expression Is Associate with Glioma Tumor Grade and Histological Type, and Acts as a Prognostic Factor in Lower-Grade Gliomas

The A disintegrin and metalloproteinase 9 (ADAM9) protein has been suggested to promote carcinoma invasion and appears to be overexpressed in various human cancers. However, its role has rarely been investigated in gliomas and, thus, in the current study we have evaluated ADAM9 expression in gliomas and examined the relevance of its expression in the prognosis of glioma patients. Clinical characteristics, RNA sequence data, and the case follow-ups were reviewed for 303 patients who had histological, confirmed gliomas. The ADAM9 expression between lower-grade glioma (LGG) and glioblastoma (GBM) patients was compared and its association with progression-free survival (PFS) and overall survival (OS) was assessed to evaluate its prognostic value. Our data suggested that GBM patients had significantly higher expression of ADAM9 in comparison to LGG patients (p < 0.001, t-test). In addition, among the LGG patients, aggressive astrocytic tumors displayed significantly higher ADAM9 expression than oligodendroglial tumors (p < 0.001, t-test). Moreover, high ADAM9 expression also correlated with poor clinical outcome (p < 0.001 and p < 0.001, log-rank test, for PFS and OS, respectively) in LGG patients. Further, multivariate analysis suggested ADAM9 expression to be an independent marker of poor survival (p = 0.002 and p = 0.003, for PFS and OS, respectively). These results suggest that ADAM9 mRNA expression is associated with tumor grade and histological type in gliomas and can serve as an independent prognostic factor, specifically in LGG patients.

Expression and Prognostic Significance of p53 in Glioma Patients: A Meta-analysis

Glioma is a brain tumor deriving from the neoplastic glial cells or neuroglia. Due to its resistance to anticancer drugs and different disease progress of individuals, patients with high-grade glioma are difficult to completely cure, leading to a poor prognosis and low overall survival. Therefore, there is an urgent need to look for prognostic and diagnostic indicators that can predict glioma grades. P53 is one of the widely studied biomarkers in human glioma. The purpose of this study was to comprehensively evaluate the significance of p53 expression in glioma grades and overall survival. We searched commonly used electronic databases to retrieve related articles of p53 expression in glioma. Overall, a total of 21 studies including 1322 glioma patients were finally screened out. We observed that the frequency of p53 immuno-positivity was higher in high-grade patients than that in low-grade category (63.8 vs. 41.6 %), and our statistic analysis indicated that p53 expression was associated with pathological grade of glioma (OR 2.93, 95 % CI 1.87-4.60, P < 0.00001). This significant correction was also found in 1-, 3- and 5-year overall survival. However, no positive relationship was found between age, sex, tumor size and p53 expression in patients with glioma. In conclusion, our results suggested that p53 immunohistochemical expression might have an effective usefulness in predicting the prognosis in patients with glioma.

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.

MicroRNA-133a inhibits the malignant behavior of glioma via downregulation of matrix metallopeptidase 9

MicroRNA (miR)-133a expression has been reported to be downregulated in numerous human malignancies. However, the expression levels and function of miR-133a have not yet been investigated in human glioma. In the present study, the expression of miR‑133a was analyzed by reverse transcription‑quantitative polymerase chain reaction. Following transfection of miR‑133a, cell proliferation, cell migration, cell invasion and luciferase assays, and western blot analysis were conducted in glioma cell lines. The present study demonstrated that miR‑133a was downregulated in human glioma tissues compared with in normal adjacent tissues. In addition, the results indicated that miR‑133a was likely to directly target matrix metallopeptidase 9 in glioma. These results suggest that miR-133a may be considered as a target for the treatment of human glioma.

miR-22 inhibits the proliferation, motility, and invasion of human glioblastoma cells by directly targeting SIRT1

Recently, microRNAs (miRNAs), a kind of small and non-coding RNA, can target the downstream molecules. Increasing evidence demonstrates that miRNAs meditate the onset and progression of a variety of tumors. In the present study, we carried out gene transfection, western blot, and reverse transcription PCR (RT-PCR) to explore the role of miR-22 in glioblastoma tissues and cell lines. Here, we verified that the expression of miR-22 was downregulated in glioblastoma tissues and cells rather than matched non-tumor tissues and normal human astrocyte (NHA) cells (p < 0.001). By contrast, SIRT1 messenger RNA (mRNA) and protein were upregulated in glioblastoma tissues and cells (p < 0.001). In vitro miR-22 mimics interfered with cell proliferation, migration, and invasion of U87 and U251 cells. Mechanically, the 3'-untranslated regions (3'-UTRs) of SIRT1 were a direct target of miR-22, leading to the decreased expression of SIRT1 protein in U87 and U251 cells. Meanwhile, miR-22 mimics also inhibited the expression of epidermal growth factor receptor (EGFR) and matrix metallopeptidase 9 (MMP9). In conclusion, miR-22 inhibited cell proliferation, migration, and invasion via targeting the 3'-UTR of SIRT1 in the progression of glioblastoma and miR-22-SIRT1 pathway can be recommended as a potential target for treatment of glioblastoma.

The involvement of anterior gradient 2 in the stromal cell-derived factor 1-induced epithelial-mesenchymal transition of glioblastoma

In recent years, it has been widely identified that the stromal cell-derived factor 1 (SDF-1) and anterior gradient 2 (AGR2) were implicated in the development of epithelial-mesenchymal transition (EMT) in a variety of cancers. However, the involvement of SDF-1-AGR2 pathway in the EMT of glioblastoma has not been investigated. In the present study, the in vitro assays were used to investigate the role of AGR2 in cell cycle, migration, and invasion. We found that the expressions of AGR2 and chemokine (C-X-C motif) receptor 4 (CXCR4) were obviously upregulated in glioblastoma cells T98G, A172, U87, and U251 than those in normal human astrocytes (NHA) (all p < 0.01), among which both U87 and U251 cells presented the highest expression (p > 0.05). Western blot revealed that SDF-1 induced the expression of p-AKT, AGR2, and EMT markers (N-cadherin, matrix metalloproteinase-2 (MMP2), and Slug) in a dose-dependent manner in U87 and U251 cells. However, the depletion of AGR2 reversed SDF-1-induced upregulation of EMT markers rather than p-AKT. Furthermore, functional analysis identified that knockdown of AGR2 induced cell cycle arrest in G0/G1 phase and suppressed the migration and invasion of U87 and U251 cells. Taken together, SDF-1-CXCR4 pathway induced the expression of AGR2 to control the progression of EMT likely via AKT pathway in the development of glioblastoma. Our findings lay a promising foundation for the SDF-1-AGR2 axis-targeting therapy in patients with glioblastoma.

Upregulated miRNA-622 inhibited cell proliferation, motility, and invasion via repressing Kirsten rat sarcoma in glioblastoma

Glioblastoma has been reported as one of the leading causes of cancer-related death, and some factors including oncogenic genes and environments are involved in tumorigenesis. MicroRNAs (miRNAs) act as a kind of small and noncoding RNA, which can target the downstream molecules. Emerging reports demonstrate that microRNAs regulate the initiation and progression of different cancers. In the present study, we conducted in vitro experiment as well as clinical studies in a cohort of 20 glioblastoma samples. We demonstrated that miR-622 expression was lower in tumor tissues and cells, when compared to normal brain tissues and normal human astrocyte (NHA) cells, while K-Ras messenger RNA (mRNA) and protein showed the opposite expression profile. Overexpression of miR-622 suppressed tumor cell proliferation, migration, and invasion of A172, U87, and U251 cells. Accordingly, the proliferating cell nuclear antigen (PCNA), matrix metallopeptidase 2 (MMP2), and MMP9 expressions were also decreased due to miR-622 overexpression. Importantly, we discovered that wild Kirsten rat sarcoma (K-Ras) was a direct target of miR-622, which decreased the expression of K-Ras protein in A172, U87, and U251 cells. In conclusion, upregulated miRNA-622 inhibited cell proliferation, migration, and invasion via repressing K-Ras in the progression of glioblastoma, and miR-622-K-Ras pathway can be recommended as a potential target for treatment of glioblastoma.

The involvement of hematopoietic pre-B cell leukemia transcription factor-interacting protein in regulating epithelial-mesenchymal transition of human spinal glioblastoma

To date, hematopoietic pre-B cell leukemia transcription factor-interacting protein (HPIP), a co-repressor for the transcription factor PBX, has been involved into the initiation and onset in a wide variety of cancers. However, the molecular mechanisms underlying HPIP-induced epithelial-mesenchymal transition (EMT) in the spinal glioblastoma have been under investigation. In the present study, spinal glioblastoma tissues, U87, and U251 cell lines were used and subjected to in vitro assays, such as RT-PCR, and Western blot. Here, in vitro assays revealed that HPIP mRNA and protein were highly expressed in five cases of spinal glioblastoma tissues, compared with non-tumor tissues. Subsequently, in vitro experiments demonstrated HPIP promoted the U87 and U251 cell growth and regulated the G1/S phase transitions in U87 and U251 cell cycle, respectively, accompanied by the increased expression of cyclin A2, cyclin B1, and cyclin D1. Furthermore, HPIP increased the expression of N-cadherin, Slug, and MMP2, and decreased the expression of E-cadherin. By contrast, knockdown of HPIP reversed HPIP-induced EMT biomarkers, migration, and invasion in U87 and U251 cells. In conclusion, our findings identified HPIP plays an important role in the progression and EMT of spinal glioblastoma, by which cell growth is improved. Thus, HPIP gene or protein could act as a useful target in the clinical practice.

The involvement of myocyte enhancer factor 2D in regulating tumor biology of cardiac myxoma

The pro-survival transcription factor myocyte enhancer factor 2D (MEF2D) is identified to exhibit pro-tumor effects based on clinical and experimental studies. However, the detailed mechanisms underlying IGF-1-MEF2D pathway-induced tumor biology in cardiac myxoma (CM) was not clear. Here, we investigated the role of MEF2D in CM tissues and cells using RT-PCR, western blot, gene silencing, et al. Our findings revealed MEF2D was significantly increased in CM tissues compared with adjacent normal tissues and closely related to tumor size. In vitro assay demonstrated that IGF-1 enhanced CM cell proliferation in a time-dependent fashion. However, knockdown of MEF2D reversed the IGF-1-induced proliferative effects on CM cells in a time-dependent fashion and further resulted in cell cycle arrest. Based on the molecular level, IGF-1 enhanced the expression of epidermal growth factor receptor (EGFR) and matrix metalloprotein 9 (MMP9) in CM cells, whereas knockdown of MEF2D was able to reduce the expression of EGFR and MMP9 compared with vector control. Furthermore, we found knockdown of MEF2D directly affected G1/S transition in cultured CM cells. In conclusion, MEF2D regulates IGF-1-induced proliferation and apoptosis in CM development, indicating IGF-1-MEF2D pathway may be a useful target for treatment.

The Clinical Implications of Transforming Growth Factor Beta in Pathological Grade and Prognosis of Glioma Patients: A Meta-Analysis

The transforming growth factor beta (TGF-β) pathway plays a key role in oncogenesis of advanced cancers. However, the effects of TGF-β pathway on gliomas are still controversial. So, it is essential to conduct a meta-analysis to determine their correlations. Eligible studies were included, and then odds ratios (ORs), standard mean differences (SMDs), and hazard ratios (HRs) with 95 % confidence intervals (95% CIs) were estimated. Funnel plots were available for evaluation of publication bias. In this meta-analysis, all 14 eligible studies involving 875 patients were included and conducted in China. Six studies with dichotomous data revealed altered TGF-β expression in glioma tissues was closely associated with high WHO grade (III + IV) (OR 4.39, 95% CI 2.90-6.63; p = 0.000), meanwhile, seven studies with continuous data also demonstrated TGF-β expression intensity extremely related to high grade (SMD -2.44, 95% CI -2.71, -2.16; p = 0.000). To our interest, TGF-β expression was associated with old age (OR 0.59, 95% CI 0.36-0.93; p = 0.025) rather than gender (OR 1.04, 95% CI 0.64-1.67; p = 0.884). Besides, TGF-β expression significantly correlated to 3-year-OS (n = 2; HR 2.53, 95% CI 1.18-5.41; p = 0.017) rather than 5-year-OS (n = 1; HR 1.04, 95% CI 0.66-1.64; p = 0.872) in glioma patients. No heterogeneity and publication bias were observed across all studies. Taken together, the present meta-analysis testifies TGF-β is potently associated with high grade and poor 3 years prognosis, and TGF-β test combined with survivin [1 Mol Neurobiol] and MMP9 [2 Mol Neurobiol] in glioma tissues should be clinically recommended as criteria of glioma grade in department of pathology.