title: Mechanism of antiproliferative activity of luteolin against stilbene-estrogen stimulation of proliferation of hamster renal epithelial cells.
abstract: In the present study, we have investigated the influence of a naturally occurring plant flavone luteolin on cell proliferation, nuclear tyrosine kinase activity, and expression of insulin-like growth factor-I (IGF-I) receptor in Syrian hamster renal epithelial cells. Diethylstilbestrol (DES)-induced cell proliferation was inhibited in a dose-dependent manner by cotreatment with luteolin. We also tested the influence of luteolin on nuclear protein tyrosine kinase activity and the expression of IGF-I receptor. The nuclear tyrosine kinase activity was inhibited in a dose-dependent manner by both genistein and luteolin. Luteolin was five times more effective in inhibiting nuclear tyrosine kinase activity than genistein. Data of kinetic constants suggest that luteolin is a noncompetitive inhibitor of nuclear protein tyrosine kinases. Co-treatment of luteolin significantly inhibited DES-induce IGF-I receptor expression. These findings indicate that blocking effects of DES-induced cell proliferation by luteolin may be through the inhibition of nuclear tyrosine kinase activity and of IGF-I receptor expression.
authors.affiliation: UNIV ALABAMA,DEPT ENVIRONM HLTH SCI,ENVIRONM TOXICOL PROGRAM,BIRMINGHAM,AL 35294. WILLIAM S MIDDLETON MEM VET ADM MED CTR,DEPT PATHOL,MADISON,WI 53705.
authors.forename: C
authors.initials: C
authors.lastname: Chen
authors.forename: M
authors.initials: M
authors.lastname: Palangat
authors.forename: T
authors.initials: T
authors.lastname: Oberley
authors.forename: D
authors.initials: D
authors.lastname: Roy