Activation of protein kinase C betaII/epsilon-c-Jun NH2-terminal kinase pathway and inhibition of mitogen-activated protein/extracellular signal-regulated kinase 1/2 phosphorylation in antitumor invasive activity induced by the polymethoxy flavonoid, nobiletin.
Flavonoids from medicinal plants have been therapeutically administered for cancer therapy. We recently reported that nobiletin (5,6,7,8,3',4'-hexamethoxy flavone) exhibits novel antitumor invasive activities by suppressing the production of pro-matrix metalloproteinases (proMMPs) and augmenting the expression of tissue inhibitor of metalloproteinases-1 (TIMP-1) in vivo and in vitro. In the present study, intracellular target molecules associated with the actions of nobiletin against tumor invasion were identified. Nobiletin inhibited the phosphorylation of mitogen-activated protein/extracellular signal-regulated kinase (MEK) 1/2, but not the activity of Ras or the phosphorylation of Raf. Moreover, a MEK1/2 inhibitor, U0126, mimicked nobiletin's ability to decrease the production of proMMPs-1 and 9 in human fibrosarcoma HT-1080 cells stimulated by 12-O-tetradecanoyl phorbol-13-acetate (TPA). In addition, neither the activity of phosphatidylinositol 3-kinase (PI3K) nor the phosphorylation of Akt was influenced by nobiletin. However, nobiletin was found to augment the phosphorylation of c-Jun NH2-terminal kinase (JNK), a downstream signal factor of the PI3K-Akt pathway, in TPA-treated HT-1080 cells. A similar augmentation of JNK phosphorylation was observed on treatment with a PI3K inhibitor, LY-294002. Furthermore, nobiletin enhancement of TIMP-1 production in TPA-stimulated HT-1080 cells was found to be diminished by adding a JNK inhibitor, SP600125. Moreover, protein kinase C (PKC) inhibitor experiments showed that PKCbetaII/epsilon were associated with the nobiletin-mediated augmentation of JNK phosphorylation. Therefore, these results introduce novel evidence that the antitumor effects of nobiletin are finely regulated by the following intracellular mechanisms: (1) the inhibition of MEK1/2 activity is involved in the suppression of MMP expression and (2) the activation of the novel PKCbetaII/epsilon-JNK pathway is associated with the augmentation of TIMP-1 expression.
Miyata
Yoshiki
Y
Department of Biochemistry and Molecular Biology, Tokyo University of Pharmacy and Life Science, School of Pharmacy, Hachioji, Tokyo, Japan.
Sato
Takashi
T
Yano
Masamichi
M
Ito
Akira
A
D000873:Anthracenes / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D002070:Butadienes / Q000494:pharmacology; D045744:Cell Line, Tumor; D017364:Collagenases / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004792:Enzyme Precursors / Q000378:metabolism; D047309:Flavones / Q000494:pharmacology*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D048370:MAP Kinase Kinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism*; D009361:Neoplasm Invasiveness; D009570:Nitriles / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism*; D064546:Protein Kinase C beta; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D013755:Tetradecanoylphorbol Acetate / Q000031:analogs & derivatives* / Q000494:pharmacology; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D048490:raf Kinases / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism
D000873:Anthracenes; D000970:Antineoplastic Agents; D002070:Butadienes; D017364:Collagenases; D004792:Enzyme Precursors; D047309:Flavones; D048031:JNK Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D020780:Matrix Metalloproteinase 9; D020929:Mitogen-Activated Protein Kinase Kinases; D009570:Nitriles; D019869:Phosphatidylinositol 3-Kinases; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D013755:Tetradecanoylphorbol Acetate; D019715:Tissue Inhibitor of Metalloproteinase-1; D048490:raf Kinases; D018631:ras Proteins; C113580:U 0126; C432165:pyrazolanthrone; C032975:12-O-tetradeca-2,4,6,8-tetranoylphorbol-13-acetate; C008661:nobiletin; C494918:AKT1 protein, human; C120487:pro-matrix metalloproteinase 9