title: Requirement for epidermal growth factor receptor tyrosine kinase and for 12-lipoxygenase activity in the expression of 12-lipoxygenase in human epidermoid carcinoma cells.
abstract: We studied the dependency of basal 12-lipoxygenase (12-LOX; arachidonate:oxygen 12-oxidoreductase, EC 1.13.11.31) expression and activity on functional protein tyrosine kinase of the epidermal growth factor receptor (EGF-R) and on 12-LOX activity in human A431 epidermoid carcinoma cells. Treatment of cells with inhibitors of high specificity for EGF-R tyrosine kinase, namely PD 153035 and 4,5-dianilinophthalimide (DAPH1), decreased cellular 12-LOX at mRNA, protein, and activity levels in a time- and dose-dependent manner, with PD 153035 being effective at concentrations below 1 microM. After 24-hr incubation with 10 microM PD 153035 or DAPH1, 12-LOX activity dropped to 14% (39%), and 12-LOX protein to 25% (24%) of control level. Inhibition of 12-LOX activity by the compound N-benzyl-N-hydroxy-5-phenylpentanamide (BHPP) also resulted in a substantial decrease in 12-LOX protein expression. 12-LOX mRNA levels were diminished or undetectable by reverse transcription-polymerase chain reaction after cell treatment with these inhibitors. Our results suggest that basal 12-LOX expression in A431 tumor cells largely depends on functional EGF-R tyrosine kinase, and that 12-LOX activity is required in the EGF-elicited intracellular signaling maintaining the expression of 12-LOX.
authors.affiliation: Division of Tumor Biochemistry, Deutsches Krebsforschungszentrum, Heidelberg, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Hagmann
authors.forename: S
authors.initials: S
authors.lastname: Borgers
mesh_terms: D001092:Arachidonate 12-Lipoxygenase / Q000096:biosynthesis* / Q000235:genetics; D001710:Biotin / Q000031:analogs & derivatives / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D066246:ErbB Receptors / Q000037:antagonists & inhibitors*; D006801:Humans; D016859:Lipoxygenase Inhibitors; D010590:Phalloidine / Q000031:analogs & derivatives / Q000494:pharmacology; D010797:Phthalimides / Q000494:pharmacology*; D011799:Quinazolines / Q000494:pharmacology*; D012333:RNA, Messenger / Q000032:analysis; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D016859:Lipoxygenase Inhibitors; D010797:Phthalimides; D011799:Quinazolines; D012333:RNA, Messenger; C060047:4-(3-(biotinylaminohexamethylenaminocarbonyl)propanoylaminomethyl)-2-methyl-1,3-dithiolane-2-yl-(Ala(7))phalloidin; D010590:Phalloidine; D001710:Biotin; D001092:Arachidonate 12-Lipoxygenase; D066246:ErbB Receptors; C088860:4-((3-bromophenyl)amino)-6,7-dimethoxyquinazoline; C098874:4,5-dianilinophthalimide