title: (-)-Epigallocatechin-3-gallate promotes pro-matrix metalloproteinase-7 production via activation of the JNK1/2 pathway in HT-29 human colorectal cancer cells.
abstract: Matrix metalloproteinase (MMP)-7 (matrilysin-1) plays significant roles in the growth, invasion, and metastasis of colorectal tumors, while (-)-epigallocatechin-3-gallate (EGCG), a green tea polyphenol with chemopreventive properties, has been shown to be an inhibitor of MMP-2 and MMP-9. In the present study, HT-29 human colorectal cancer cells were treated with EGCG to examine its effects on pro-MMP-7 induction and production using RT-PCR and western blot analyses. Surprisingly, EGCG (10-100 microM) treatment increased both intracellular and extracellular pro-MMP-7 protein levels (2.6-8.4-fold and 1.9-6.4-fold, respectively) in dose- and time-dependent manner, with a significant upregulation of its mRNA expression. EGCG also activated extracellular signal-regulated protein kinase (ERK)1/2, c-JUN NH2-terminal kinase (JNK)1/2 and p38 mitogen-activated protein kinase (MAPK), as previously reported. In addition, the polyphenol triggered the phosphorylation of c-JUN (Ser63 and Ser73) and induced c-JUN/c-FOS, thereby increasing the DNA binding activity of activator protein-1 (AP-1), as shown by an AP-1 luciferase reporter assay. Pharmacological blockade of MAPK activities suggested that pro-MMP-7 expression was induced via JNK1/2 activation, but not in the case of ERK1/2 or p38 MAPK. N-Acetyl-L-cysteine, superoxide (O2-) dismutase and catalase attenuated the EGCG-induced pro-MMP-7 production, suggesting an involvement of oxidative stress in these events. Conversely, EGCG spontaneously generated O2- in a cell-free system that utilized a cytochrome C reduction method. Further, (-)-epicatechin-3-gallate (25 and 100 microM) and green tea polyphenols (33 and 132 microg/ml) induced pro-MMP-7 expression, whereas (-)-epicatechin and (-)-epigallocatechin (100 microM each) did not. Induction of pro-MMP-7 expression by EGCG was also shown in another human colorectal adenocarcinoma cell line, Caco-2. Our results suggest that some green tea catechins induce pro-MMP-7 production via O2- production and the activation of JNK1/2, c-JUN, c-FOS and AP-1 in HT-29 cells.
authors.affiliation: Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: Mihye
authors.initials: M
authors.lastname: Kim
authors.forename: Akira
authors.initials: A
authors.lastname: Murakami
authors.forename: Kyuichi
authors.initials: K
authors.lastname: Kawabata
authors.forename: Hajime
authors.initials: H
authors.lastname: Ohigashi
mesh_terms: D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms; D004789:Enzyme Activation; D004792:Enzyme Precursors / Q000235:genetics*; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D020783:Matrix Metalloproteinase 7 / Q000235:genetics*; D048055:Mitogen-Activated Protein Kinase 8 / Q000378:metabolism*; D048056:Mitogen-Activated Protein Kinase 9 / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D016588:Anticarcinogenic Agents; D004792:Enzyme Precursors; D002392:Catechin; C045651:epigallocatechin gallate; D048056:Mitogen-Activated Protein Kinase 9; D048055:Mitogen-Activated Protein Kinase 8; D048051:p38 Mitogen-Activated Protein Kinases; D020783:Matrix Metalloproteinase 7