20-HETE-producing enzymes are up-regulated in human cancers.
BACKGROUND
20-Hydroxyeicosatetraenoic acid (20-HETE), a metabolite of arachidonic acid (AA) produced by the CYP4A and CYP4F enzyme families has been reported to induce mitogenic and angiogenic responses both in vitro and in vivo, and inhibitors of this pathway reduced growth of brain and kidney tumors.


METHODS
Real-Time PCR, western blot and immunohistochemistry were used to compare the expression of CYP4A/F mRNA and protein levels in human cancer tissue samples versus normal controls. Liquid chromatography/mass spectrometry analysis (LC-MS/MS) was performed to measure 20-HETE formation in tumor homogenates. Activation of Ras in human proximal tubule epithelial cells (HRPTEC) treated with stable agonist of 20-HETE was measured using a Ras pull-down detection kit.


RESULTS
The expression of CYP4A/4F genes was markedly elevated in thyroid, breast, colon, and ovarian cancer samples in comparison to matched normal tissues. Furthermore, the levels of the CYP4F2 protein and of 20-HETE were higher in ovarian cancer samples compared to normal control tissues. A stable 20-HETE agonist induced activation of the small-GTPase Ras in HRPTEC cells.


CONCLUSIONS
The present finding of elevated expression of CYP4A/F enzymes in human cancer tissue suggests that 20-HETE inhibitors and antagonists may be useful in the treatment of cancer.
Kidney Disease Center, Department of Medicine and Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Anna
A
Alexanian
Bradley
B
Miller
Richard J
RJ
Roman
Andrey
A
Sorokin
D042926:Cytochrome P-450 CYP4A / Q000235:genetics / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D000072470:Cytochrome P450 Family 4; D004847:Epithelial Cells / Q000166:cytology / Q000201:enzymology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D006893:Hydroxyeicosatetraenoic Acids / Q000819:agonists / Q000378:metabolism*; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000201:enzymology; D009369:Neoplasms / Q000201:enzymology* / Q000235:genetics; D053719:Tandem Mass Spectrometry
D006893:Hydroxyeicosatetraenoic Acids; C055987:20-hydroxy-5,8,11,14-eicosatetraenoic acid; D003577:Cytochrome P-450 Enzyme System; D000072470:Cytochrome P450 Family 4; C117480:CYP4F2 protein, human; D042926:Cytochrome P-450 CYP4A