The epoxyeicosatrienoic acid-stimulated phosphorylation of EGF-R involves the activation of metalloproteinases and the release of HB-EGF in cancer cells.
OBJECTIVE
To test the hypothesis that the epoxyeicosatrienoic acid (EET)-induced transactivation of EGF-R depends on the activation of metalloproteinases and the subsequent release of HB-EGF in cancer cells.


METHODS
Exogenous 14,15-EET were added to four human-derived cancer cell lines Tca-8113, A549, HepG2, and MDA-MB-231, or these same cell lines were transfected with a mutant CYP epoxygenase (CYP102 F87V, an active 14,15-epoxygenase). The effects of elevated EET levels on the phosphorylation of tyrosine residues in the EGF receptor and on ERK1/2 activation were then assessed.


RESULTS
Both the addition of 14,15-EET and the transfection of cells with CYP102 F87V markedly increased the phosphorylation of the tyrosine residues of EGF-R and ERK1/2, an effect that was blocked by a selective EGF-R tyrosine kinase inhibitor (tyrphostin AG1478), a broad-spectrum metalloproteinase inhibitor (1,10-phenanthroline), and an inhibitor of HB-EGF release (CRM197) in Tca-8113 cells. In addition, AG1478, 1,10-phenanthroline, and CRM197 also inhibited the tyrosine phosphorylation of EGF-R and ERK1/2 that was induced by 14,15-EET in the A549, HepG2, and MDA-MB-231 cell lines.


CONCLUSIONS
These results suggest that the EET-induced transactivation of EGF-R depends on activation of metalloproteinases and the subsequent release of HB-EGF in cancer cell lines.
The Institute of Hypertension and Department of Internal Medicine, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China.
Li-ming
LM
Cheng
Jian-gang
JG
Jiang
Zi-yong
ZY
Sun
Chen
C
Chen
Ryan T
RT
Dackor
Darryl C
DC
Zeldin
Dao-wen
DW
Wang
D001095:Arachidonic Acids / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004789:Enzyme Activation; D004797:Enzyme-Linked Immunosorbent Assay; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D045726:Metalloproteases / Q000378:metabolism*; D010618:Phenanthrolines / Q000494:pharmacology; D010766:Phosphorylation; D015533:Transcriptional Activation
D001095:Arachidonic Acids; C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D010618:Phenanthrolines; D066246:ErbB Receptors; D045726:Metalloproteases; C025205:1,10-phenanthroline