Expression of matrix metalloproteinase-2 in glial and neuronal tumor cell lines: inverse correlation with proliferation rate

Induction Effects of Apigenin, Luteolin and Vinpocetin on Neutral Endopeptidase (NEP) and Angiotensin-Converting Enzyme Activity (ACE) of SK-N-SH Cells

The long-term effects of a number of flavonoids (such as apigenin, luteolin and amentoflavone) and vinpocetine on the neutral endopeptidase (NEP) and angiotensin-converting enzyme (ACE) were investigated. It was shown that apigenin, luteolin and vinpocetin are able to induce the activity of both NEP and ACE associated with the inhibition of the proliferation of the neuroblastoma cell line SK-N-SH. Amentoflavone has no effect on either NEP or ACE activity. An additional enhancement of cellular NEP activity could be detected after the treatment of the cells with a combination of both arabinosylcytosine and either apigenin or luteolin. This effect supports the assumption that apigenin and luteolin influence directly the gene expression of NEP. Taking into account the significant role of NEP and ACE in the degradation of amyloid beta peptides, the induction of both enzymes by long-term treatment with apigenin, luteolin and vinpocetine may have a beneficial effect regarding the prevention of the formation of amyloid plaques and the effect of these substances may be discussed as neuroprotective.

The Role of Chemotherapy in the Treatment of Malignant Astrocytomas

Malignant astrocytomas are aggressive neoplasms with a dismal prognosis despite optimal treatment. Maximal resective surgery is traditionally complemented by radiation therapy. Chemotherapy is now used on patients as initial therapy when their functional status is congruent with further treatment. The classic agents used are nitrosoureas, but temozolomide has taken the front seat recently, with recent data demonstrating increased survival when this agent is used concurrently with radiation therapy in newly diagnosed glioblastoma patients. A new class of agents, refered to as biological modifiers, are increasingly used in clinical trials in an effort to affect the intrinsic biologic aberrations harboured by tumor cells. These drugs comprise differentiation agents, anti-angiogenic agents, matrix-metalloproteinase inhibitors and signal transduction inhibitors, among others. This article reviews the standard cytotoxic agents that have been used to treat malignant astrocytomas, and the different combination regimens offering promise. In addition, recent advances with biological modifiers are also discussed.

Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) in the tumors of central nervous system (CNS)

Malignant neoplasms of the central nervous system (CNS) account for about 1.3 % of all tumors and 2.2 % of all cancer-related deaths. CNS tumors consist of heterogeneous group of neoplasms, including different variants of primary brain tumors and metastatic neoplasms. Advanced imaging techniques improved the neuroradiological diagnostic accuracy, although these methods are not specific enough for differentiation of CNS tumors, thus new approaches of patients' diagnosis are critically needed. The best solution for the diagnosis of patients with CNS tumors could be easily available biomarkers, which could be useful for the management of CNS neoplasms. Biomarkers should facilitate the diagnosis, monitor of treatment response and assess the prognosis of patients' survival. Currently, except for rare germ cell tumors, there is a lack of knowledge on biochemical markers for CNS neoplasms. Therefore, in this paper we summarized and referred a number of comprehensive reviews concerning the role of matrix metalloproteinases (MMPs) and their tissue inhibitors in tumor progression, including CNS neoplasms as well as described the general biochemistry of MMPs and their tissue inhibitors. Moreover, we presented the wide variety of previous findings, where authors suggested the significance of selected MMPs and their tissue inhibitors as potential biomarkers of human tumors, including CNS tumors. However, future investigations are needed to be performed before some of these enzymes could finally be used as biomarkers of specific types of CNS neoplasms.

The relationship between the expression of tumor matrix-metalloproteinase and the characteristics of magnetic resonance imaging of human gliomas

Objective

To investigate the relationship between the expression level of matrix-metalloproteinases (MMPs) with the pathological grades and MRI characteristics of human gliomas.

Methods

Prior pre- and post-contrast enhancement MRI was performed on 31 patients with gliomas, which were confirmed by post-operational pathology. The expression of MMP-2 and MMP-9 were determined by immunohistochemical staining in both a low grading group (grades I and II, n = 20) and high grading group (grades III and IV, n = 11).

Results

Compared to the low grading group, the expression levels of MMP-2, MMP-9, as well as the tumor edema index (EI), enhanced percentage (EP) and maximum diameters were significantly greater in the high grading group. MMP-2 and MMP-9 expression were correlated with the tumor EI, EP and the maximum diameters. There were no differences in MMP-2 and MMP-9 expression between the unclear border definition group and the clear border definition group, whereas the MMPs expression levels were greater in the heterogeneous signal group than in the homogeneous signal group.

Conclusion

The expression level of MMPs is correlated with the invasion ability of human gliomas. The MRI parameters, such as tumor EI, EP, maximum diameter, and signal heterogeneity technically reflect the expression level of MMPs, and can be used to estimate the tumor's malignant behavior, thus providing the guidance for clinical therapies.

Chlorotoxin Fused to IgG-Fc Inhibits Glioblastoma Cell Motility via Receptor-Mediated Endocytosis

Chlorotoxin is a 36-amino acid peptide derived from Leiurus quinquestriatus (scorpion) venom, which has been shown to inhibit low-conductance chloride channels in colonic epithelial cells. Chlorotoxin also binds to matrix metalloproteinase-2 and other proteins on glioma cell surfaces. Glioma cells are considered to require the activation of matrix metalloproteinase-2 during invasion and migration. In this study, for targeting glioma, we designed two types of recombinant chlorotoxin fused to human IgG-Fcs with/without a hinge region. Chlorotoxin fused to IgG-Fcs was designed as a dimer of 60 kDa with a hinge region and a monomer of 30 kDa without a hinge region. The monomeric and dimeric forms of chlorotoxin inhibited cell proliferation at 300 nM and induced internalization in human glioma A172 cells. The monomer had a greater inhibitory effect than the dimer; therefore, monomeric chlorotoxin fused to IgG-Fc was multivalently displayed on the surface of bionanocapsules to develop a drug delivery system that targeted matrix metalloproteinase-2. The target-dependent internalization of bionanocapsules in A172 cells was observed when chlorotoxin was displayed on the bionanocapsules. This study indicates that chlorotoxin fused to IgG-Fcs could be useful for the active targeting of glioblastoma cells.

Urinary biomarkers predict brain tumor presence and response to therapy

PURPOSE

A major difficulty in treating brain tumors is the lack of effective methods of identifying novel or recurrent disease. In this study, we have evaluated the efficacy of urinary matrix metalloproteinases (MMP) as diagnostic biomarkers for brain tumors.

EXPERIMENTAL DESIGN

Urine, cerebrospinal fluid, and tissue specimens were collected from patients with brain tumors. Zymography, ELISA, and immunohistochemistry were used to characterize the presence of MMP-2, MMP-9, MMP-9/neutrophil gelatinase-associated lipocalin (NGAL), and vascular endothelial growth factor (VEGF). Results were compared between age- and sex-matched controls and subjected to univariate and multivariate statistical analyses.

RESULTS

Evaluation of a specific panel of urinary biomarkers by ELISA showed significant elevations of MMP-2, MMP-9, MMP-9/NGAL, and VEGF (all P < 0.001) in samples from brain tumor patients compared with controls. Multiplexing MMP-2 and VEGF provided superior accuracy compared with any other combination or individual biomarker. Receiver-operating characteristics curves for MMP-2 and VEGF showed excellent discrimination. Immunohistochemistry identified these same proteins in the source tumor tissue. A subset of patients with longitudinal follow-up revealed subsequent clearing of biomarkers after tumor resection.

CONCLUSION

We report, for the first time, the identification of a panel of urinary biomarkers that predicts the presence of brain tumors. These biomarkers correlate with presence of disease, decrease with treatment, and can be tracked from source tissue to urine. These data support the hypothesis that urinary MMPs and associated proteins are useful predictors of the presence of brain tumors and may provide a basis for a novel, noninvasive method to identify new brain tumors and monitor known tumors after treatment.

A recurrent craniopharyngioma illustrates the potential usefulness of urinary matrix metalloproteinases as noninvasive biomarkers: case report

OBJECTIVE

Matrix metalloproteinases (MMPs) are a class of enzymes involved in angiogenesis, tumor growth, and metastasis. Recent reports indicate that urinary MMPs predict the presence of several types of tumors, including those of the breast, prostate, and bladder. Ongoing protocols at our institution are evaluating the efficacy of urinary MMPs as diagnostic markers for brain tumors and gastrointestinal disease.

CLINICAL PRESENTATION

An 8-year-old girl underwent transsphenoidal resection of a craniopharyngioma at the age of 6 years with radiographic gross total resection. Two years later, her urine was analyzed for MMPs as part of an evaluation for gastrointestinal complaints. Despite normal gastrointestinal evaluation results, her urinary MMP levels were markedly elevated. She subsequently sought treatment for recurrent craniopharyngioma.

INTERVENTION

The craniopharyngioma was resected again. Approximately 1 year after surgery, no sources of the elevated MMPs have been found other than the recurrent craniopharyngioma. Follow-up analysis of urinary MMPs demonstrated clearing of markers concordant with tumor treatment.

CONCLUSION

We report the finding of elevated urinary MMPs in the setting of a recurrent craniopharyngioma. These biomarkers correlate with the presence of disease, clear with treatment, and can be tracked from source tissue to urine. The findings of this case support the hypothesis that urinary MMPs may be a useful predictor of the presence or recurrence of brain tumors. To our knowledge, this is the first report supporting the proof-of-principle concept that urinary MMPs may have potential usefulness in predicting the presence of brain tumors, expanding the spectrum of tumors capable of being diagnosed with this technique.

Heterogeneity in retinoic acid signaling in neuroblastomas: Role of matrix metalloproteinases in retinoic acid-induced differentiation

Causes of retinoid resistance often observed in neuroblastomas are unknown. We studied all trans-retinoic acid (RA) signaling in neuroblastoma cells differing in N-myc levels in terms of neurite formation, expression of tissue transglutaminase, neuronal marker proteins, matrix metalloproteinases (MMPs), and activation of Rac1 and Cdc42. Poor invasiveness observed in SH-SY5Y, LA-N-5, and SMS-KCNR cells was associated with RA-induced neurite formation, Cdc42 activation and N-myc down regulation; expression of constitutively active Cdc42 down regulated N-myc expression and reduced invasion in RA-resistant SK-N-BE(2) and IMR32 cells. RA treatment for 24 h transiently increased invasion and expression of MMP9 in SH-SY5Y, LA-N-5 and MMP2 in SMS-KCNR cells. MMP inhibition prevented RA-induced neurite formation indicating a role in differentiation. Variation in RA signaling thus follows a defined pattern and relates to invasive potential. A defective RA signaling might result in retinoid resistance and unpredictable clinical outcome observed in some neuroblastomas.

Matrix metalloproteinase-2 and-9 expression in astrocytic tumors

In this study, we investigated whether the expression of matrix metalloproteinase (MMP)-2 and MMP-9 correlated with invasiveness, proliferative potential, or prognosis in astrocytic tumors. Thirty-seven astrocytic tumors (8 diffuse astrocytomas, 15 anaplastic astrocytomas, and 14 glioblastomas) and three gliomatosis cerebri were investigated immunohistochemically. The invasive glioma group included three cases of gliomatosis cerebri and two of glioblastoma associated with cerebrospinal fluid dissemination. The expression of MMP-2 and MMP-9 was evaluated by assigning an immunohistochemical (IHC) score defined as the sum of expression frequency and intensity. mRNA expression patterns for the MMPs were also evaluated in a reverse transcription-polymerase chain reaction assay. Neither the MMP-2 nor MMP-9 IHC score was related to histological malignancy. The MMP-2 IHC score of the invasive glioma group was significantly higher than those of other kinds of astrocytic tumors. However, the MMP-9 IHC score did not correlate with dissemination among astrocytic tumors. An inverse correlation was observed between the MIB-1 labeling index and the IHC scores of MMP-2, but it was not significant. A Kaplan-Meyer survival analysis revealed no significant relationship between the survival rate and MMP-2 or MMP-9 expression. Our study showed that MMP-2 expression, but not MMP-9 expression, may be associated with invasion in astrocytic tumors.

Enhancement of neutral endopeptidase activity in SK-N-SH cells by green tea extract

Green tea extract (EFLA85942) is able to induce specifically the neutral endopeptidase (NEP) activity and to inhibit the proliferation of SK-N-SH cells; the angiotensin-converting enzyme (ACE) activity is not influenced under the same conditions. The treatment of the cells with arabinosylcytosine and green tea extract results in a strong enhancement of cellular NEP activity whereas cellular ACE activity was not changed significantly, indicating a green tea extract-specific regulation of NEP expression. Because of its role in the degradation of amyloid beta peptides this enzyme induction of NEP by long term treatment with green tea extract may have a beneficial effect regarding the prevention of forming amyloid plaques.