Downregulation of MMP-9 in ERK-mutated stable transfectants inhibits glioma invasion in vitro

SUMMARYWe previously showed that MMP-9 inhibition using an adenoviral-mediated delivery of MMP-9 siRNA (Ad-MMP-9), caused senescence in medulloblastoma cells. Regardless of whether or not, Ad-MMP-9 would induce apoptosis, the possible signaling mechanism is still obscure. In this report, we demonstrate that Ad-MMP-9 induced apoptosis in DAOY cells as determined by propidium iodide and TUNEL staining. Ad-MMP-9 infection induced the release of cytochrome-c, activation of caspases-9-3, and cleavage of PARP. Ad-MMP-9 infection stimulated ERK, and EMSA indicated an increase in NF-κB activation. ERK inhibition, using kinase dead mutant for ERK, ameliorated NF-κB activation and caspase-mediated apoptosis in Ad-MMP-9 infected cells. β1-integrin expression in Ad-MMP-9 infected cells also increased, and this increase was reversed by the reintroduction of MMP-9. We found that, addition of β1 blocking antibodies inhibited Ad-MMP-9-induced ERK activation. Taken together, our results indicate that MMP-9 inhibition induces apoptosis due to altered β1 integrin expression in medulloblastoma. In addition, ERK activation plays an active role in this process and functions upstream of NF-κB activation to initiate the apoptotic signal.

Section: Transfection With Plasmidsmentioning

confidence: 99%

Blockade of Tumor Growth Due to Matrix Metalloproteinase-9 Inhibition Is Mediated by Sequential Activation of β1-Integrin, ERK, and NF-κB

Bhoopathi

Chetty

Kunigal

et al. 2008

“…These changes in cell physiology have been previously linked to the basal level of ERK activation (65,66). The extent of cell growth inhibition (nearly 100%) was unanticipated.…”

Section: Fig 4 Erk Activation By Csuparmentioning

confidence: 75%

Soluble Urokinase-type Plasminogen Activator Receptor Inhibits Cancer Cell Growth and Invasion by Direct Urokinase-independent Effects on Cell Signaling

Thomas

et al. 2003

The urokinase-type plasminogen activator receptor (uPAR) is released from human cancers and is readily detected in blood. In animal models, soluble uPAR (Su-PAR) antagonizes cancer progression; however, the mechanism by which SuPAR functions in vivo remains unclear. It is generally thought that SuPAR scavenges uPA and prevents its interaction with membrane-anchored uPAR. In this study, we demonstrate a novel molecular mechanism by which SuPAR may inhibit cancer progression. We show that SuPAR has the potential to directly and in a uPA-independent manner block the signaling activity of membrane-anchored uPAR. Whether SuPAR inhibits signaling is cell type-specific, depending on the state of the endogenous uPA-uPAR signaling system. In uPAR-deficient cells that lack endogenous uPAR signaling, including uPAR؊/؊ murine embryonic fibroblasts and human embryonal kidney 293 cells, SuPAR functions as a partial signaling agonist that activates ERK/mitogen-activated protein kinase. By contrast, in cells with potent autocrine uPA-uPAR signaling systems, including MDA-MB 231 breast cancer cells and low density lipoprotein receptor-related protein-1-deficient murine embryonic fibroblasts, SuPAR substantially decreases ERK activation. The mechanism probably involves competitive displacement of membrane-anchored uPAR-uPA complex from signaling adaptor proteins. As a result of its effects on cell signaling, SuPAR blocks cell growth and inhibits cellular invasion of Matrigel TM . Cleavage of SuPAR by proteinases increases its signaling agonist activity and reverses its inhibitory effects on growth and invasion. Thus, proteolytic cleavage represents a molecular switch that neutralizes the anticancer activity of SuPAR.

“…Epidermal growth factor-and scatter factor/hepatocyte growth factor-induced MMP-9 expression in keratinocytes was mediated by ERK1/2 activation and could be inhibited by treatment with MEK inhibitor PD98059 (38). Moreover, transfection of constitutively active MEK increased MMP-9 expression in NIH3T3 cells, whereas catalytically inactive ERK1 blocked MMP-9 expression in glioblastoma cells (39). In contrast, in the current study a negative correlation was observed between p38 MAPK activity and calcium-induced MMP-9 gene expression in normal/premalignant oral keratinocytes.…”

Section: P38 Mapk Negatively Regulates Mmp-9 In Oral Cancermentioning

confidence: 90%

Calcium-induced Matrix Metalloproteinase 9 Gene Expression Is Differentially Regulated by ERK1/2 and p38 MAPK in Oral Keratinocytes and Oral Squamous Cell Carcinoma

Mukhopadhyay

Munshi

Kambhampati³

et al. 2004

Matrix metalloproteinases (MMPs) play an important role in the invasive behavior of a number of cancers including oral squamous cell cancer (OSCC), and increased expression of MMP-9 is correlated with invasive and metastatic OSCC. Because calcium is an important regulator of keratinocyte function, the effect of modulating extracellular calcium on MMP-9 expression in OSCC cell lines was evaluated. Increasing extracellular calcium induced a dose-dependent increase in MMP-9 expression in immortalized normal and premalignant oral keratinocytes, but not in two highly invasive OSCC cell lines. Differential activation of MAPK signaling was also induced by calcium. p38 MAPK activity was downregulated, whereas ERK1/2 activity was enhanced. Pharmacologic inhibition of p38 MAPK activity or expression of a catalytically inactive mutant of the upstream kinase MAPK kinase 3 (MKK3) increased the calcium induced MMP-9 gene expression, demonstrating that p38 MAPK activity negatively regulated this process. Interestingly blocking p38 MAPK activity enhanced ERK1/2 phosphorylation, suggesting reciprocal regulation between the ERK1/2 and p38 MAPK pathways. Together these data support a model wherein calcium-induced MMP-9 expression is differentially regulated by the ERK1/2 and p38 MAPK pathways in oral keratinocytes, and the data suggest that a loss of this regulatory mechanism accompanies malignant transformation of the oral epithelium.Oral squamous cell carcinoma (OSCC) 1 is the most common malignancy of the oral cavity causing more deaths than any other oral disease (1, 2). Although OSCC is characterized by local, regional, and distant spread, the biochemical factors that underlie dissemination are poorly understood (1, 3). OSCC tumors demonstrate a progressive lack of basement membrane staining, more diffuse invasion, and a higher frequency of lymph node metastasis, suggesting that basement membrane loss reflects metastatic potential (4 -7). This is consistent with immunohistochemical and in situ hybridization studies of human OSCC tumors that implicate enzymes belonging to the matrix metalloproteinase (MMP) family, including MMP-9 (92-kDa gelatinase B), in basement membrane proteolysis and tissue invasion. The presence of gelatinolytic activity attributable to activated MMP-9 in OSCC biopsy specimens correlates with immunohistochemical staining of frozen sections and is enhanced in both highly invasive and metastatic cases, suggesting a correlation between MMP-9 activity and metastatic potential (8,9). Additional studies of human tumors have shown that MMP-9 is up-regulated in diffuse invasive OSCC specimens, with predominant localization to the invasive front (4, 10). At the cellular level, modulation of MMP-9 expression via phorbol ester treatment leads to enhanced invasive behavior (8 -10), whereas blocking MMP-9 expression in vivo reduces invasion in an orthotopic murine model of OSCC (11). These data support the hypothesis that MMP-9 is an important determinant of the invasive phenotype in OSCC.Oral keratinocytes express a...