Characterization of an 8-lipoxygenase activity induced by the phorbol ester tumor promoter 12-O-tetradecanoylphorbol-13-acetate in mouse skin in vivo.
An enzymatic activity has been found in cytosolic preparations from mouse epidermis which catalyzes the formation of 8-hydroperoxyeicosatetraenoic acid/8-hydroxyeicosatetraenoic acid (8-HPETE/8-HETE) from arachidonate. In contrast to 12-lipoxygenase this enzyme activity was not detectable in normal (untreated) mouse skin but only after in vivo treatment with the phorbol ester tumor promoter TPA (12-O-tetradecanoylphorbol-13-acetate). The induction showed a maximum at 24 h after TPA treatment strictly depended on the age of the mice and the TPA dose and was prevented by cycloheximide. The primary product formed from arachidonic acid was 8-HPETE, and the enzyme seems not to possess a significant peroxidase activity. This result as well as studies with specific inhibitors and its cytosolic localization indicates this enzyme to be a member of the lipoxygenase family. Most of the 8-lipoxygenase activity is located in cells of the suprabasal compartment of the epidermis. In spite of being a cytosolic enzyme 8-lipoxygenase appeared to be lipophilic to some extent and was activated by lecithin. The enzyme did not require calcium ions or ATP and showed a pH optimum at 7.5-8.0. 8-HPETE/8-HETE levels in mouse epidermis in vivo were determined by gas chromatography-mass spectrometry and found to be strongly increased after phorbol ester treatment, in agreement with the induction of 8-lipoxygenase observed.
Fürstenberger
G
G
Department of Biochemistry, German Cancer Research Center, Heidelberg.
Hagedorn
H
H
Jacobi
T
T
Besemfelder
E
E
Stephan
M
M
Lehmann
W D
WD
Marks
F
F
D000375:Aging / Q000378:metabolism; D000818:Animals; D001091:Arachidonate Lipoxygenases / Q000378:metabolism*; D002384:Catalysis; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D004789:Enzyme Activation; D005260:Female; D006863:Hydrogen-Ion Concentration; D006893:Hydroxyeicosatetraenoic Acids / Q000096:biosynthesis / Q000378:metabolism; D007700:Kinetics; D015289:Leukotrienes / Q000096:biosynthesis / Q000378:metabolism; D008081:Liposomes; D051379:Mice; D010713:Phosphatidylcholines / Q000378:metabolism; D012867:Skin / Q000187:drug effects* / Q000201:enzymology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D006893:Hydroxyeicosatetraenoic Acids; D015289:Leukotrienes; D008081:Liposomes; D010713:Phosphatidylcholines; C047629:8-hydroperoxyeicosatetraenoic acid; C047628:8-hydroxyeicosatetraenoic acid; D001091:Arachidonate Lipoxygenases; C054192:arachidonate 8-lipoxygenase; D013755:Tetradecanoylphorbol Acetate