Abstract
Mitogen-activated protein kinases (MAPKs) play a major role in the mitogenic signal transduction pathway and are essential components of both growth and differentiation. Constitutive activation of the MAPK cascade is associated with the carcinogenesis and metastasis of human breast and renal cell carcinomas. The gelatinases B (MMP-9) and A (MMP-2) are 2 members of the matrix metalloproteinase (MMPs) family which are expressed in human cancers and thought to play a critical role in tumor cell invasion and metastasis. In a previous study, we have shown that EGF and amphiregulin upregulate MMP-9 in metastatic SKBR-3 cells but have no effect on MMP-2 secretion. We now investigated specific step(s) in EGF-induced signalling associated with regulation of cell proliferation and MMP-9 induction. EGF-induced signalling in SKBR-3 cells was blocked by relatively specific inhibitors either on ras (FPT inhibitor-1) or P13 kinase (Wortmannin) or by reduction in EGF-induced tyrosine kinase activity (RG 13022). Blocking these signalling pathways significantly inhibited of EGF-induced cell proliferation but only partially reduced in EGF-induced MMP-9 secretion. In contrast, when SKBR-3 cells were exposed to MEK inhibitor (PD 98059) or MAPK inhibitors (Apigenin or MAPK antisense phosphorothioate oligodeoxynucleotides), EGF-induced cell proliferation, MMP-9 induction and invasion through reconstituted basement membrane were significantly reduced. Our results suggest that interfering with MAPK activity may provide a novel means of controlling growth and invasiveness of tumors in which the signalling cascade is activated.
Publication types
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amphiregulin
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Breast / enzymology*
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Breast Neoplasms / enzymology*
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Breast Neoplasms / pathology
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Calcium-Calmodulin-Dependent Protein Kinases / physiology*
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Cell Division / drug effects
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Cells, Cultured
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EGF Family of Proteins
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Enzyme Induction / drug effects
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Enzyme Inhibitors / pharmacology
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Enzyme Precursors / biosynthesis*
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Enzyme Precursors / genetics
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Epidermal Growth Factor / pharmacology
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Epithelial Cells / drug effects
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Epithelial Cells / enzymology
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Female
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Fibroblasts / drug effects
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Fibroblasts / enzymology
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Gelatinases / biosynthesis*
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Gelatinases / genetics
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Gene Expression Regulation, Neoplastic* / drug effects
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Glycoproteins / pharmacology
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Growth Substances / pharmacology
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Humans
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Intercellular Signaling Peptides and Proteins*
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MAP Kinase Kinase Kinase 1*
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Metalloendopeptidases / biosynthesis*
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Metalloendopeptidases / genetics
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Neoplasm Invasiveness
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Neoplasm Proteins / biosynthesis*
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Neoplasm Proteins / genetics
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Neoplasm Proteins / physiology
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Phosphatidylinositol 3-Kinases / metabolism
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Phosphoinositide-3 Kinase Inhibitors
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Protein Serine-Threonine Kinases / antagonists & inhibitors
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Protein Serine-Threonine Kinases / metabolism
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Protein-Tyrosine Kinases / antagonists & inhibitors
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Protein-Tyrosine Kinases / metabolism
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Proto-Oncogene Proteins p21(ras) / antagonists & inhibitors
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Proto-Oncogene Proteins p21(ras) / metabolism
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Signal Transduction / drug effects
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Stromal Cells / drug effects
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Stromal Cells / enzymology
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Transfection
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Tumor Cells, Cultured / drug effects
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Tumor Cells, Cultured / enzymology
Substances
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AREG protein, human
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Amphiregulin
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EGF Family of Proteins
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Enzyme Inhibitors
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Enzyme Precursors
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Glycoproteins
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Growth Substances
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Intercellular Signaling Peptides and Proteins
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Neoplasm Proteins
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Phosphoinositide-3 Kinase Inhibitors
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Epidermal Growth Factor
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Protein-Tyrosine Kinases
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Protein Serine-Threonine Kinases
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Calcium-Calmodulin-Dependent Protein Kinases
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MAP Kinase Kinase Kinase 1
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MAP3K1 protein, human
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Gelatinases
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Metalloendopeptidases
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progelatinase
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HRAS protein, human
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Proto-Oncogene Proteins p21(ras)