Matrix metalloproteinase-9 expression is increased in astrocytic glioma and associated with prognosis of patients

Proline Metabolism in WHO G4 Gliomas Is Altered as Compared to Unaffected Brain Tissue

Proline metabolism has been identified as a significant player in several neoplasms, but knowledge of its role in gliomas is limited despite it providing a promising line of pursuit. Data on proline metabolism in the brain are somewhat historical. This study aims to investigate alterations of proline metabolism in gliomas of WHO grade 4 (GG4) in the context of the brain. A total of 20 pairs of samples were studied, consisting of excised tumor and unaffected brain tissue, obtained when partial brain resection was required to reach deep-seated lesions. Levels of proline oxidase/proline dehydrogenase (POX/PRODH), Δ1-pyrroline-5-carboxylate reductases (PYCR1/2/3), prolidase (PEPD), and metalloproteinases (MMP-2, MMP-9) were assessed, along with the concentration of proline and proline-related metabolites. In comparison to normal brain tissue, POX/PRODH expression in GG4 was found to be suppressed, while PYCR1 expression and activity of PEPD, MMP-2, and -9 were upregulated. The GG4 proline concentration was 358% higher. Hence, rewiring of the proline metabolism in GG4 was confirmed for the first time, with a low-POX/PRODH/high-PYCR profile. High PEPD and MMPs activity is in keeping with GG4-increased collagen turnover and local aggressiveness. Further studies on the mechanisms of the interplay between altered proline metabolism and the GG4 microenvironment are warranted.

Gold Nanorods Inhibit Tumor Metastasis by Regulating MMP-9 Activity: Implications for Radiotherapy

Dysregulation of matrix metalloproteinase (MMP) is strongly implicated in tumor invasion and metastasis. Nanomaterials can interact with proteins and have impacts on protein activity, which provides a potential strategy for inhibiting tumor invasion and metastasis. However, the regulation of MMP activity by nanomaterials has not been fully determined. Herein, we have found that gold nanorods (Au NRs) are able to induce the change of the secondary structure of MMP-9 and thereby inhibit their activity. Interestingly, the inhibition of MMP-9 activity is highly dependent on the aspect ratio of Au NRs, and an aspect ratio of 3.3 shows the maximum inhibition efficiency. Molecular dynamics simulations combined with mathematical statistics algorithm reveal the binding behaviors and interaction modes of MMP-9 with Au NRs in atomic details and disclose the mechanism of aspect ratio-dependent inhibition effect of Au NRs on MMP-9 activity. Au NRs with an aspect ratio of 3.3 successfully suppress the X-ray-activated invasion and metastasis of tumor by inhibiting MMP-9 activity. Our findings provide important guidance for the modulation of MMP-9 activity by tuning key parameters of nanomaterials and demonstrate that gold nanorods could be developed as potential MMP inhibitors.

The diagnostic and prognostic potential of the EGFR/MUC4/MMP9 axis in glioma patients

Glioblastoma is the most aggressive form of brain cancer, presenting poor prognosis despite current advances in treatment. There is therefore an urgent need for novel biomarkers and therapeutic targets. Interactions between mucin 4 (MUC4) and the epidermal growth factor receptor (EGFR) are involved in carcinogenesis, and may lead to matrix metalloproteinase-9 (MMP9) overexpression, exacerbating cancer cell invasiveness. In this study, the role of MUC4, MMP9, and EGFR in the progression and clinical outcome of glioma patients was investigated. Immunohistochemistry (IHC) and immunofluorescence (IF) in fixed tissue samples of glioma patients were used to evaluate the expression and localization of EGFR, MMP9, and MUC4. Kaplan-Meier survival analysis was also performed to test the prognostic utility of the proteins for glioma patients. The protein levels were assessed with enzyme-linked immunosorbent assay (ELISA) in serum of glioma patients, to further investigate their potential as non-invasive serum biomarkers. We demonstrated that MUC4 and MMP9 are both significantly upregulated during glioma progression. Moreover, MUC4 is co-expressed with MMP9 and EGFR in the proliferative microvasculature of glioblastoma, suggesting a potential role for MUC4 in microvascular proliferation and angiogenesis. The combined high expression of MUC4/MMP9, and MUC4/MMP9/EGFR was associated with poor overall survival (OS). Finally, MMP9 mean protein level was significantly higher in the serum of glioblastoma compared with grade III glioma patients, whereas MUC4 mean protein level was minimally elevated in higher glioma grades (III and IV) compared with control. Our results suggest that MUC4, along with MMP9, might account for glioblastoma progression, representing potential therapeutic targets, and suggesting the 'MUC4/MMP9/EGFR axis' may play a vital role in glioblastoma diagnostics.

Relationship between expression of PD-L1 and tumor angiogenesis, proliferation, and invasion in glioma

Programmed death ligand 1 (PD-L1) is highly expressed in many cancers. We investigated the expression of PD-L1 and its relationship with vascular endothelial growth factor (VEGF), matrix metalloproteinase-9 and KI-67 expression in 64 patients with primary glioma. The expression rate of PD-L1 in glioma patients was 78.12%. PD-L1 levels correlated with the tumor grade (p = 0.013), VEGF status (p = 0.002) and KI-67 status (p = 0.002). In addition, PD-L1 levels correlated positively with VEGF (r = 0.314, p = 0.011) and KI-67 (r = 0.391, p = 0.001) levels when the data were treated as continuous variables. This is the first report suggesting that PD-L1 is important for glioma angiogenesis and proliferation. Thus, further research should be conducted to assess the combination of targeted VEGF therapy and anti-PD-L1 immunotherapy for the treatment of glioma.

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.

Reduction of α-dystroglycan expression is correlated with poor prognosis in glioma

Dystroglycan (DG), a multifunctional protein dimer of non-covalently linked α and β subunits, is best known as an adhesion and transduction molecule linking the cytoskeleton and intracellular signaling pathways to extracellular matrix proteins. Loss of DG binding, possibly by degradation or disturbed glycosylation, has been reported in a variety of cancers. DG is abundant at astroglial endfeet forming the blood-brain barrier (BBB) and glia limitans; so, we examined if loss of expression is associated with glioma. Expression levels of α-DG and β-DG were assessed by immunohistochemistry in a series of 78 glioma specimens to determine the relationship with tumor grade and possible prognostic significance. α-DG immunostaining was undetectable in 44 of 49 high-grade specimens (89.8%) compared to 15 of 29 low-grade specimens (51.72%) (P<0.05). Moreover, loss of α-DG expression was an independent predictor of shorter disease-free survival (DFS) (hazards ratio (HR) = 0.142, 95% confidence interval (CI) 0.033-0.611, P=0.0088). Reduced expression of both α-DG and β-DG was also a powerful negative prognostic factor for DFS (HR=2.556, 95% CI 1.403-4.654, P=0.0022) and overall survival (OS) (HR=2.193, 95% CI 1.031-4.666, P=0.0414). Lack of α-DG immunoreactivity is more frequent in high-grade glioma and is an independent predictor of poor clinical outcome. Similarly, lack of both α-DG and β-DG immunoreactivity is a strong independent predictor of clinical outcome.

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

In the recent years, matrix metalloproteinase 9 (MMP-9) has been focused on as an indicator of glioma grade and prognosis, especially in China. However, all results resulted in many conflicts. So, it is necessary to conduct a meta-analysis to secure a convincing correlation between MMP-9 and grade and prognosis. Eligible studies were included via multiple searches, and then odds ratios (ORs) and hazard ratios (HRs) with 95% confidence intervals (95% CIs) were estimated. Funnel plots were available for evaluation of publication bias. In addition, heterogeneity and sensitivity were also analyzed. In the present meta-analysis, 23 articles were allowed for inclusion with total 1,635 patients. Coincidentally, all studies were conducted in Chinese populations. High MMP-9 expression in gliomas was closely associated with high WHO grade (III+IV) (n = 22, OR = 5.25, 95% CI = 4.09-6.73; p = 0.000), while MMP-9 expression did not correlate to age (n = 4, OR = 1.02, 95 % CI = 0.67-1.54; p = 0.929) and gender (n = 5, OR = 0.91, 95% CI = 0.63-1.33; p = 0.632). Besides, overall survival analysis from two articles revealed MMP-9 expression significantly predicted 5-year-OS (HR = 6.44, 95% CI = 3.88-10.70; p = 0.000) in glioma patients. No heterogeneity and publication bias were observed across all studies. To conclude, this meta-analysis suggests MMP-9 is potently associated with high grade and poor 5 years prognosis, and MMP-9 test of glioma tissues should be established in department of pathology as a routine in clinical practice.

Expression of matrix metalloproteinase-2 and 9 in cervical intraepithelial neoplasia and cervical carcinoma among different age groups of premenopausal and postmenopausal women

PURPOSE

The objective was to study the gelatinolytic activity of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in preinvasive and invasive carcinoma of the uterine cervix. The expressions were analysed against different age groups, as to demonstrate whether the expression of MMP-2 and MMP-9 is an early or a late event during the progression of cervical cancer. Additionally, the diagnostic accuracy of MMP-2 and MMP-9 was evaluated with ROC curve.

METHODS

A total number of 180 samples of cervical tissue were studied for MMP-2 and MMP-9 gelatinolytic activity. The cases were selected as to include 63 normal cases, 94 CIN cases and 23 cervical carcinoma cases. Among 94 CIN cases, 40 were CIN1, 26 were CIN2 and 28 were CIN3, as reported by histopathology. The gelatinolytic activities of MMP-2 and MMP-9 were evaluated by gelatin zymography in premenopausal and postmenopausal groups.

RESULTS

MMP-2 expressions (latent and active) were very low in control samples, followed by increase in CIN1, decrease in CIN2 and further increase in advance stages. MMP-9 had also shown the same expression pattern that of MMP-2. While comparing the expression of MMP-2 and MMP-9 in different age groups, we found initial CIN stages were prevalent in early age that expressed considerable amount of MMP-2 and MMP-9, and advance stages of carcinoma cervix were prevalent at an elderly age.

CONCLUSION

Both MMP-2 and MMP-9 have role in cancer progression and remodelling of the ectocervix. Although expression level varies intricately, a distinctive ROC curve demonstrated MMP-2 active form and MMP-9 form could be used in diagnostic purpose in detection of cervical lesion and cancer.