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Results for “Matrix Metalloproteinases, Secreted”

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PubMed2001

Transforming growth factor-alpha promotes mouse blastocyst outgrowth and secretion of matrix metalloproteinases.

OBJECTIVE: To study the effect of transforming growth factor-alpha (TGF-alpha) on early stage of embryo implantation. METHODS: Mouse blastocysts were cultured in vitro in medium containing various concentrations of TGF-alpha. Blastocyst implantation capacity was evaluated by calculating the percentage of embryos with attachment or outgrowth. Matrix metalloproteinases (MMPs) secretion of blastocysts was observed using gelatin zymography. RESULTS: There was no significant difference in the percentage of attachment between control and TGF-alpha treated groups, but the percentage of outgrowth of TGF-alpha treated groups was significantly higher than that of the control group after 24 h culturing. Gelatin zymography showed that blastocysts cultured in TGF-alpha treated groups started secreting MMPs earlier than those in the control group. CONCLUSION: TGF-alpha is involved in regulating the mouse embryo implantation process by promoting blastocyst outgrowth and secreting matrix matalloproteinases.

Animals↗

PubMed2003

Matrix metalloproteinase-3 secretion from human colonic subepithelial myofibroblasts: role of interleukin-17.

BACKGROUND: Subepithelial myofibroblasts (SEMFs) play a role in extracellular matrix (ECM) metabolism in the colon. In this study, we investigated the effects of interleukin (IL)-17, IL-1beta, and tumor necrosis factor (TNF)-alpha on matrix metalloproteinase (MMP)-3 secretion in colonic SEMFs. METHODS: MMP-3 secretion and MMP-3 mRNA expression were determined by Western and Northern blotting, respectively. The secretion of tissue inhibitor of matrix metalloproteinase (TIMP)-1 was determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: In human colonic SEMFs, MMP-3 secretion and MMP-3 mRNA expression were induced by IL-17, IL-1beta, and TNF-alpha. The effect of IL-17 was observed, but this was weak as compared with those induced by IL-1beta or TNF-alpha. A c-Jun/activating protein-1 (AP-1) inhibitor, curcumin, reduced the IL-17-, IL-1beta-, and TNF-alpha-induced MMP-3 mRNA expression, and mitogen-activated protein (MAP) kinase inhibitors (U0126, PD098059, and SB203580) also blocked MMP-3 secretion. There findings indicate a role for AP-1 and MAP kinases in cytokine-induced MMP-3 secretion. Furthermore, costimulation by IL-17 + IL-1beta and by IL-17 + TNF-alpha induced a marked increase in MMP-3 secretion. The costimulatory effects of these combinations were also observed for TIMP-1 mRNA expression and TIMP-1 secretion. CONCLUSIONS: Colonic SEMFs actively secreted MMP-3 in response to IL-17, IL-1beta, and TNF-alpha. This was coupled with TIMP-1 secretion. Colonic SEMFs may play an important role in ECM turnover via MMP secretion.

Blotting, Northern↗

PubMed2003

Collagen of chronically inflamed skin is over-modified and upregulates secretion of matrix metalloproteinase 2 and matrix-degrading enzymes by endothelial cells and fibroblasts.

In order to investigate the properties of collagen in chronically inflamed tissue, we isolated collagen from the ear skin of mice with chronic contact dermatitis and examined its biochemical characteristics and the functions that regulate the secretion of matrix metalloproteinase 2 and collagen-degrading enzymes from endothelial cells and fibroblasts. Collagen in skin with chronic contact dermatitis comprised 60% type I collagen and 40% type III collagen, which latter is higher than the content of type III collagen in control skin (35%). The denaturation temperature was higher (42 degrees C) than that of control skin (39 degrees C). The alpha2 chain of type I collagen was over-hydroxylated at both proline and lysine residues. Segment-long-spacing crystallites of type I collagen were unusually connected in tandem. Collagen of chronically inflamed skin was less susceptible to matrix metalloproteinase 2 after heat denaturation. Endothelial cells and fibroblasts secreted an increased amount of matrix metalloproteinase 2 when cultured on a gel formed from the collagen of chronically inflamed skin. Collagen-degrading activity secreted from fibroblasts was also upregulated when cells were in contact with collagen of chronically inflamed skin. These results suggest that the collagen in chronically inflamed tissue has altered biochemical characteristics and functions, which may affect the pathogenesis of the chronic skin disease.

Animals↗

PubMed2000

A role for FAK in the Concanavalin A-dependent secretion of matrix metalloproteinase-2 and -9.

To study the signaling pathway critical for the secretion of matrix metalloproteinases (MMPs), we examined the role of focal adhesion kinase (FAK) in Concanavalin A (Con A)-stimulated cells. We established a cell line in which FAK gene was conditionally inducible by use of FAK-null fibroblasts and the tetracycline repression system. In this cell line, FAK expression was undetectable in the presence of tetracycline but induced within 1 day by the removal of the drug. We found that FAK expression augmented the Con A-dependent secretion of MMP-9 and MMP-2. In contrast, proteolytic activation of MMP-2 by Con A-treatment did not require FAK expression. In addition, activation of MMP-secretion and tyrosine phosphorylation of FAK by Con A, but not the proteolytic activation of MMP-2, required attachment of the cells to the extracellular matrix. Taken together, our results suggest that the FAK signaling pathway play a pivotal role in the secretion of MMPs.

Animals↗

PubMed1998

Both focal adhesion kinase and c-Ras are required for the enhanced matrix metalloproteinase 9 secretion by fibronectin in ovarian cancer cells.

Cell adhesion to the extracellular matrix appears to trigger a cascade of intracellular signalings. We have shown previously that treatment of ovarian cancer cells with peritoneal conditioned medium or purified fibronectin (FN) activated matrix metalloproteinase 9 secretion and, thereby, cancer cell invasion. By use of antisense oligonucleotides to focal adhesion kinase (FAK) and a dominant-negative mutant of ras (S17Nras), we found that both FAK and c-Ras were required for the activation of matrix metalloproteinase 9 secretion by FN. In addition, both antisense oligonucleotides to FAK and S17Nras inhibited mitogen-activated protein kinase activation by FN treatment, suggesting the involvement of mitogen-activated protein kinase in the FN-dependent signaling.

Cell Adhesion Molecules↗

PubMed2000

Further evidence for secretion of matrix metalloproteinase-1 by Meckel's chondrocytes during degradation of the extracellular matrix.

We examined the possibility that chondrocytes in Meckel's cartilage might secrete matrix metalloproteinase-1 (MMP-1) during degradation of the extracellular matrix. Evidence for the secretion of MMP-1 was obtained by immunohistochemical staining and immunoelectron microscopy, in addition to general histochemical staining for proteoglycans. Not only staining with toluidine blue and alcian blue but also immunostaining for chondroitin sulfate proteoglycan (CSPG) revealed that levels of glycoproteins are rapidly reduced at the late stage of degradation. MMP-1 was detected continuously in cells from chondrocytes at the early stage to hypertrophic chondrocytes at the late stage. Immunoelectron microscopy revealed that the deposition of colloidal golds shifted from an intracellular localization in chondrocytes at the early stage to pericellular spaces at the late stage. The localization of tissue inhibitor of the metalloproteinase-1 (TIMP-1) at the early stage was similar to that of MMP-1, but the level of TIMP-1 decreased significantly in hypertrophic cartilage. These findings suggest that MMP-1 is present continuously in Meckel's chondrocytes but that the active form, which degrades the extracellular matrix, is the MMP-1 that accumulates in the pericellular spaces around hypertrophic chondrocytes.

Alcian Blue↗

PubMed2001

Lacidipine [correction of Lalsoacidipine] modulates the secretion of matrix metalloproteinase-9 by human macrophages.

Activated macrophages within the arterial wall secrete matrix-degrading metalloproteinases (MMPs) that weaken the atherosclerotic plaque and contribute to its fissuration. Preclinical studies have shown that calcium antagonists may reduce atherogenesis in the arterial wall. In the present study we evaluated the effect of lacidipine on 92-kDa gelatinase B (MMP-9) expression in human macrophages in cultures. Cells were treated for 24 h with lacidipine and the conditioned media were analyzed. Lacidipine (1-20 microM) significantly reduced, in a dose-dependent manner, MMP-9 potential gelatinolytic capacity up to 50%. When MMP-9 expression was stimulated by treatment with phorbol esters or tumor necrosis factor-alpha, lacidipine was able to inhibit this enhanced gelatinolytic capacity up to 50 and 60%, respectively. Western blot analysis and enzyme-linked immunosorbent assay showed a reduction of MMP-9 protein actually released by cells. The addition of lacidipine in the incubation media determined no significant variation in Ca(2+) concentration. The drug did not affect MMP-9 mRNA levels, but it effectively reduced the amount of both active and total free MMP-9 secreted by human macrophages. Lacidipine reduced also the secretion of the tissue inhibitor of metalloproteinase-1 (TIMP-1); however we observed an overall reduction of the gelatinolytic activity of the cells. Finally, peritoneal macrophages, obtained from mice treated with lacidipine, showed a reduced secretion of MMP-9. Together, our data indicate that lacidipine may potentially exert an antiatherosclerotic activity by modulating the secretion of MMP-9 by macrophages. This, in addition to the previously demonstrated inhibition of cholesterol esterification, may contribute to increase plaque stability.

Animals↗

PubMed2006

Adenosine inhibits matrix metalloproteinase-9 secretion by neutrophils: implication of A2a receptor and cAMP/PKA/Ca2+ pathway.

Matrix metalloproteinases (MMPs), and in particular MMP-9 secreted by neutrophils, are capable of degrading the matrix components of the heart and are thought to be the driving force behind myocardial matrix remodeling after infarction. Adenosine, a naturally produced nucleoside, has been shown to have cardioprotective effects and to inhibit secretion of various cytokines. The aim of our study was to determine the effect of adenosine on the secretion of MMP-9 by neutrophils. Neutrophils were isolated from healthy volunteers through Ficoll and Dextran sedimentation. Neutrophils were activated by N-formylmethionyl-leucyl-phenylalanine (fMLP) in the presence or absence of adenosine or adenosine analogs. Zymography and enzyme linked immunosorbent assay were used to measure MMP-9 secretion. Adenosine (1 micromol/L) decreased the fMLP-induced MMP-9 secretion by 30+/-2% (n=8, P<0.001). The effect was dose-dependent and was not specific to fMLP because adenosine also inhibited MMP-9 secretion by LPS- or H(2)O(2)-stimulated neutrophils. The effect of adenosine was mimicked by the adenosine A2a receptor agonist CGS21680 and was inhibited by both the A2a antagonist SCH5826 and A2a RNA silencing. The A3 agonist IB-MECA moderately decreased fMLP-induced MMP-9 secretion. Agonists and antagonists of the other types of adenosine receptors had no significant effect. Adenosine increased intracellular cAMP concentration and accelerated the return to baseline of the intracytoplasmic calcium peak. The inhibition of MMP-9 secretion by adenosine, as well as the calcium effect, was prevented by the protein kinase A inhibitor H-89. In conclusion, we show here that adenosine inhibits MMP-9 secretion by neutrophils. Our results suggest that this effect implies the A2a receptor and is mediated through the cAMP/PKA/Ca(2+) pathway. Therefore, adenosine may represent a new approach to prevent matrix degradation and remodeling after myocardial injury.

Adenosine↗

PubMed2007

Matrix metalloproteinase-3 secretion from human pancreatic periacinar myofibroblasts in response to inflammatory mediators.

OBJECTIVES: Matrix metalloproteinases (MMPs) play roles in the pathophysiology of pancreatic disorders. However, the regulation of MMP-3 secretion in the pancreas remains unclear. In this study, we assessed the expression of MMP-3 in human pancreatic periacinar myofibroblasts. METHODS: MMP-3 secretion and MMP-3 mRNA expression were determined by enzyme-linked immunosorbent assay and real-time polymerase chain reaction, respectively. RESULTS: In human pancreatic myofibroblasts, MMP-3 secretion and mRNA expression were induced by interleukin (IL)-17, IL-1beta, and tumor necrosis factor (TNF) -alpha, respectively. The effects of IL-17 were detected as similar in extent to those induced by IL-1beta or TNF-alpha. Costimulation by IL-17 plus IL-1beta and/or IL-17 plus TNF-alpha induced a synergistic increase in MMP-3 secretion, although the costimulatory effects of these combinations were not detected in tissue inhibitor of matrix metalloproteinase-1 secretion. Adenovirus-mediated transfer of a stable form of IkappaBalpha markedly inhibited the effects of IL-17, IL-1beta, and TNF-alpha. Mitogen-activated protein kinase inhibitors (U0126, PD098059, and SB203580) also blocked MMP-3 secretion. These findings indicate a role for nuclear factor-kappaB and mitogen-activated protein kinases in cytokine-induced MMP-3 secretion. CONCLUSIONS: Pancreatic periacinar myofibroblasts actively secrete MMP-3 in response to IL-17, IL-1beta, and TNF-alpha. Pancreatic myofibroblasts may play an important role in extracellular matrix turnover via MMP-3 secretion in the pancreas.

Adenoviridae↗

PubMed2003

Arfaptin 1 inhibits ADP-ribosylation factor-dependent matrix metalloproteinase-9 secretion induced by phorbol ester in HT 1080 fibrosarcoma cells.

Matrix metalloproteinase-9 (MMP-9) is a collagenolytic enzyme secreted by cancer cells and involved in invasiveness and metastasis. Its secretion from human fibrosarcoma HT 1080 cells is markedly enhanced by phorbol 12-myristate 13-acetate (PMA) and abolished by brefeldin A, an inhibitor of ADP-ribosylation factor (ARF) activation. These results support a role for ARF in PMA-stimulated MMP-9 secretion. Overexpression of arfaptin 1, a 39 kDa ARF-binding protein that inhibits in vitro activation of cholera toxin ADP-ribosyltransferase and phospholipase D (PLD) by ARF, inhibited PMA-stimulated MMP-9 and PLD activation. These data are in agreement with previous results demonstrating a significant role for PLD in regulating MMP-9 secretion.

ADP-Ribosylation Factors↗

PubMed2001

Relaxin increases secretion of matrix metalloproteinase-2 and matrix metalloproteinase-9 during uterine and cervical growth and remodeling in the pig.

Matrix metalloproteinases are proteolytic enzymes that degrade the extracellular matrix and are essential for tissue remodeling. Uterine and cervical growth require remodeling of structural barriers to cell invasion and matrix metalloproteinase-2 and -9 degrade type IV collagen, the major component of basement membranes. Relaxin stimulates uterine and cervical growth and remodeling, which includes remodeling of support elements such as basement membranes. The objective of this study was to determine whether relaxin alters the production and/or activity of matrix metalloproteinase-2 and -9 in the uterus or cervix of the pig. The growth-promoting effects of relaxin were elicited by administering relaxin to prepubertal gilts every 6 h for 54 h. The expression of matrix metalloproteinase-2 and matrix metalloproteinase-9 was characterized by gel zymography, and proteins were quantified by immunoblotting. Total enzyme activity was measured using matrix metalloproteinase-specific fluorescent substrate assays. In both uterine and cervical tissues, immunoreactive matrix metalloproteinase-2 and matrix metalloproteinase-9 protein expression was similar in relaxin-treated and control animals. However, tissue-associated gelatinase activity was attenuated by relaxin (P < 0.05). In contrast, relaxin significantly increased the secretion of active matrix metalloproteinase-2 and -9 protein into uterine fluid (P < 0.05). Given the importance of matrix metalloproteinases in extracellular matrix degradation, the observation that relaxin promotes uterine secretion of matrix metalloproteinase-2 and -9 supports the concept that relaxin facilitates the growth and remodeling of reproductive tissues by increasing extracellular proteolysis in the pig reproductive tract.

Animals↗

PubMed2005

[Effect of progesterone on the secretion of matrix metalloproteinase-2 and matrix metalloproteinase-9 in human ectopic endometrial stromal cells].

OBJECTIVE: To determine the effect of progesterone on the secretion of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) in ectopic endometrial stromal cells. METHODS: Ectopic endometrial stromal cells were obtained from 17 patients with endometriosis. Endometrial stromal cells were obtained from 12 patients with endometriosis and 14 cases of controls. Ectopic endometrial stromal cells of 15 cases were treated with progesterone. Culture supernatants of these stromal cells were analyzed for MMP-2 and MMP-9 by zymography. RESULTS: Endometriotic stromal cells released significantly higher levels of MMP-2 and MMP-9 than endometrial stromal cells from women with and without endometriosis. Progesterone at 10(-9) mol/L caused endometriotic stromal cells a significant reduction MMP-2 and MMP-9 levels. When progesterone concentration was increased from 10(-9) mol/L to 10(-7) mol/L, the release of MMP-9 was almost completely inhibited, wherease that of MMP-2 was not completely inhibited. CONCLUSION: Progesterone may inhibit the secretion of MMP-2 and MMP-9 in ectopic endometrial stromal cells, especially MMP-9.

Adult↗

PubMedDate not supplied

The different stimulatory effect of normal tissues on the secretion of matrix metalloproteinases and their inhibitors by human ovarian cancer cells.

To investigate the influence of normal tissues on secretion of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) by ovarian cancer cells, conditioned medium of several normal human tissues (peritoneum, myometrium, and ovary) was added to ovarian cancer cells (NOM1). MMPs were detected by zymography and TIMP-1 levels were assayed by ELISA. The MMP-9 level was significantly higher in peritoneal conditioned medium than in myometrial and ovarian conditioned medium, but the TIMP-1 level was the lowest. Addition of conditioned medium from these normal tissues to NOM1 cells increased the levels of MMPs and TIMP-1 in NOM1 conditioned medium. Peritoneal conditioned medium induced the highest MMP-9 level in NOM1 conditioned medium, while TIMP-1 was the lowest. Conditioned medium from the normal tissues also significantly increased invading cell numbers, with peritoneal conditioned medium being the most potent. These results showed that secretion of MMPs and TIMP-1 is regulated by normal tissues and peritoneum provides the best conditions for ovarian cancer cell invasion.

Collagenases↗

PubMed2004

Id-1 and Id-2 proteins as molecular markers for human prostate cancer progression.

PURPOSE: Id proteins are dominant-negative regulators of basic helix-loop-helix transcription factors that control malignant cell behavior in many different tissues. This study aimed to identify the potential role of Id-1 and Id-2 proteins as molecular makers for prostate cancer progression. EXPERIMENTAL DESIGN: Using the technique of immunohistochemistry, we determined Id-1 and Id-2 expression in a panel of 67 human prostate biopsies. We also manipulated Id-1 and Id-2 expression in LNCaP and PC3 prostate cancer cell lines and determined the effects on invasion in vitro, matrix metalloproteinase secretion, and proliferation. RESULTS: Both Id-1 and Id-2 proteins were up-regulated during human prostate cancer progression in vivo and were overexpressed in highly aggressive prostate cancer cells. In vitro, constitutive expression of Id-1, and to a lesser extent Id-2, converted nonaggressive LNCaP prostate cancer cells into more proliferative and invasive cells and increased their secretion of matrix metalloproteinases. Conversely, the down-regulation of Id-2 expression in highly metastatic PC3 cells reduced their growth potential and invasiveness. CONCLUSIONS: We propose that both Id-1 and Id-2 proteins control prostate cancer cell phenotypes and could serve as molecular markers of aggressive human prostate cancer.

Biomarkers, Tumor↗

PubMed2003

Induction of matrix metalloproteinase-9 secretion from human keratinocytes in culture by ultraviolet B irradiation.

BACKGROUND: Matrix metalloproteinases (MMPs) are known as important enzymes involved in tissue metabolism. Among them, MMP-2 and MMP-9 are termed gelatinases, but their specific roles in vivo are still unknown, including their expression patterns following ultraviolet (UV) irradiation. OBJECTIVE: To elucidate the effects of UV irradiation on the skin, we analyzed the expression of MMP-2 and MMP-9 by primary human keratinocytes in culture. METHODS: We evaluated the enzymatic functions of MMP-2 and MMP-9 by gelatin-zymography, and of MMP-9 expression by immunofluorescence, using cultured keratinocytes after UV irradiation. RESULTS: The secretion of MMP-2 (72 kDa) remained at low levels under all conditions examined. Although MMP-9 (92 kDa) secretion was not induced by UVA, it was stimulated by UVB irradiation in a dose-dependent manner. In addition, an enzyme-linked immunosorbent assay showed the tendency to increase for the involucrin expression following UVB exposure. Cell viability was decreased by UVB irradiation in contrast to the induction of MMP-9 and involucrin. CONCLUSION: These results suggest that the induction of MMP-9 secretion is related to the inflammation including apoptosis of keratinocytes resulting from UVB irradiation.

Cell Survival↗

PubMed2000

TGFbeta1 stimulates the secretion of matrix metalloproteinase 2 (MMP2) and the invasive behavior in human ovarian cancer cells, which is suppressed by MMP inhibitor BB3103.

The present study investigated the modulatory role of transforming growth factor beta 1 (TGFbeta1) on the secretion of matrix metalloproteinases (MMPs) and tested whether the altered secretion of MMPs could directly affect the invasive behavior of ovarian cancer cells. To this aim, human ovarian cancer SKOV3 cells were treated once with vehicle or various concentrations of TGFbeta1 for 24 h. Gelatinase activities in conditioned media were analyzed by zymography and densitometry. TGFbeta1 dose-dependently stimulated the secretion of a 68-kDa gelatinase, which was characterized as an MMP because its activity was inhibited by a metalloproteinase inhibitor 1,10-phenanthroline, and by a synthetic MMP inhibitor BB3103. In addition, we used aminophenylmercuric acetate (APMA) to activate latent gelatinases. APMA time-dependently decreased the activity of 68-kDa gelatinase, and increased the activities of 64- and 62-kDa gelatinolytic bands. The 68-kDa gelatinase was further characterized as MMP2 (gelatinase A) by immunoblotting analysis. We then tested TGFbeta1 effect on the invasive potential of SKOV3 cells as assessed by the migration ability through reconstituted basement membrane, and further investigated whether TGFbeta1 may act through modulating the MMP activity to affect ovarian cancer cell invasion. The results show that TGFbeta1 stimulated the invasive behavior of SKOV3 cells, and that MMP inhibitor BB3103 abrogated this effect of TGFbeta1. In conclusion, this study indicates that TGFbeta1 may act partly through stimulating the secretion of MMP in promoting the invasive behavior of human ovarian cancer cells. Furthermore, this work supports the idea that specific MMP inhibitors of the hydroxamate class could be therapeutically useful in controlling cancer cell invasion/metastasis.

Blotting, Western↗

PubMed1997

Use of tetracycline as an inhibitor of matrix metalloproteinase activity secreted by human bone-metastasizing cancer cells.

Bone metastases are a common complication in prostate and breast cancer patients. It leads to extensive morbidity and eventually mortality. Matrix metalloproteinases are implicated in various steps of development of metastasis, through their ability to degrade the extracellular matrix. Increased matrix metalloproteinase activity of tumor cells has been associated with a higher metastatic potential. Inhibitors of metalloproteinases have been shown to effectively reduce or prevent the formation of metastases. The family of tetracyclines is able to inhibit matrix metalloproteinase activity through chelation of the zinc ion at the active site of the enzyme. Using tumor cell lines relevant to bone metastases, i.e. PC-3, MDA-MB-231, Hs696, B16/F1, we showed that tetracycline and derivatives of tetracycline, namely doxycycline and minocycline, also induced cytotoxicity. The effective concentrations are relatively high for plasma, but are clinically achievable in the bone, since tetracyclines are osteotropic. All four bone-metastasizing tumor cells produced and secreted various matrix metalloproteinases. Doxycycline was able to inhibit the activity of 72- and 92-kDa type IV collagenase secreted by bone-metastasizing cells by 79-87%. These characteristics could make tetracycline a unique candidate as a therapeutic agent to prevent bone metastases in cancer patients with a high likelihood for development of bone metastasis. Studies using animal models of experimental bone metastasis will be necessary to confirm this.

Adenocarcinoma↗

PubMed2002

FGF-2 and TPA induce matrix metalloproteinase-9 secretion in MCF-7 cells through PKC activation of the Ras/ERK pathway.

Matrix metalloproteinases (MMPs) play an important role in cancer metastasis. Here, we investigated the effect of fibroblast growth factor-2 (FGF-2) and 12-O-tetradecanoylphorbol-13-acetate (TPA) on the secretion of type IV collagenases (MMP-2, MMP-9) in breast cancer MCF-7 cells. As shown by gelatin zymography, both FGF-2 and TPA stimulated the secretion of MMP-9 in MCF-7 cells while they did not change the level of MMP-2 secretion. Signaling cascade studies indicated that both FGF-2 and TPA induced Ras activation, c-Raf phosphorylation, mitogen-activated protein kinase/ERK kinase (MEK(1/2)) phosphorylation, and extracellular signal-regulated kinase (ERK(1/2)) phosphorylation. The FGF-2- and TPA-induced MMP-9 secretion was significantly inhibited by transient transfection of MCF-7 cells with dominant negative Ras (Ras-N17) and by treatment with MEK(1/2) inhibitor PD98059. A pan-protein kinase C (PKC) inhibitor, GF109203X, was found to totally abolish the FGF-2- and TPA-induced MMP-9 secretion and ERK(1/2) phosphorylation. Use of isoform-specific PKC inhibitors such as Rotllerin and Gö6976 suggested, moreover, that the PKC-delta isoform is a likely component of FGF-2 and TPA trophic signaling. These results demonstrated that FGF-2 and TPA induce MMP-9 secretion in MCF-7 cells mainly through PKC-dependent activation of the Ras/ERK(1/2) signaling pathway.

Acetophenones↗