Activation of two distinct MAPK pathways governs constitutive expression of matrix metalloproteinase-1 in human pancreatic cancer cell lines.
Elevated matrix metalloproteinase-1 (MMP-1) expression is known to correlate with poor prognosis of pancreatic cancer. We investigated the molecular mechanisms of constitutive expression of MMP-1 in pancreatic cancer cell lines. Expression of MMP-1 mRNA and protein as well as its enzymatic activity were observed in three pancreatic cancer cell lines. Transient transfection assays of two MMP-1 promoter/luciferase constructs (full-length 4.4-kb or proximal 0.6-kb region) showed high levels of transcription in pancreatic cancer cells compared with non-MMP-1 producing cells. The 0.6-kb promoter region of MMP-1 gene contained three activator protein-1 (AP-1) sites and the strong AP-1 activity was detected by electrophoretic mobility shift assays (EMSAs). In these cells, production and phosphorylation of c-Jun were commonly observed. Phosphorylated c-Jun NH2-terminal kinase (p-JNK) and activator transcription factor-2 (p-ATF-2) were also detected in two of the three cell lines. Phosphorylated extracellular signal-regulated kinase (p-ERK) was observed in one. The promoter activity, AP-1-binding activity and MMP-1 production were suppressed by a specific inhibitor of JNK or MEK. K-ras mutation, reported to be present in three cell lines used, is known to activate JNK and ERK pathways. Considering the facts together, our results revealed that activation of JNK/AP-1 or ERK/AP-1 pathway plays crucial roles in constitutive transactivation of MMP-1 in these cancer cells. This study contributes to provide new insights into strategies for inhibiting tumor cell invasion in pancreatic cancer.
Endo
Hitoshi
H
Department of Community Health, Tokai University School of Medicine, Isehara, Kanagawa Prefecture 259-1193, Japan.
Watanabe
Tetsu
T
Sugioka
Yoshihiko
Y
Niioka
Maki
M
Inagaki
Yutaka
Y
Okazaki
Isao
I
D015153:Blotting, Western; D045744:Cell Line, Tumor; D024202:Electrophoretic Mobility Shift Assay; D015870:Gene Expression; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D020935:MAP Kinase Signaling System / Q000502:physiology*; D020781:Matrix Metalloproteinase 1 / Q000096:biosynthesis* / Q000235:genetics; D010190:Pancreatic Neoplasms / Q000201:enzymology* / Q000235:genetics; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018808:Transcription Factor AP-1 / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D018808:Transcription Factor AP-1; D020781:Matrix Metalloproteinase 1