title: Inhibition of cytochrome P450 1A1 by antisense phosphorothioate oligonucleotide in Hepa lclc7 cells.
abstract: The influence of an antisense phosphorothioate oligonucleotide has been investigated on 7-ethoxyresorufin O-deethylase (EROD) activity and CYP1A1 protein in wild type mouse hepatoma Hepa lclc7 (Hepa-1) cells. The results show that administration of a 15-mer antisense phosphorothioate oligonucleotide in ribonucleoside-free minimum essential medium effectively inhibited UV-oxidized tryptophan-inducible EROD activity and CYP1A1 protein. The inhibition of EROD activity was dose- and time-dependent. The inhibition of oxidized tryptophan-inducible EROD activity after administration of 5 microM antisense oligonucleotide for 18 hours was 74% over the control oligonucleotide-administered cells. There was no effect of the control or antisense oligonucleotide on the cell growth. This is the first demonstration that inducible CYP1A1 can be effectively inhibited by antisense phosphorothioate oligonucleotide in Hepa-1 cells. Utility of this approach should be useful in elucidating the role(s) of CYP1A1 in chemical carcinogenesis.
authors.affiliation: Department of Pathology, College of Medicine, University of California at Irvine 92697, USA.
authors.forename: R K
authors.initials: RK
authors.lastname: Sindhu
authors.forename: M
authors.initials: M
authors.lastname: Mitsuhashi
authors.forename: Y
authors.initials: Y
authors.lastname: Kikkawa
mesh_terms: D000818:Animals; D019363:Cytochrome P-450 CYP1A1 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D004790:Enzyme Induction; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007700:Kinetics; D051379:Mice; D016376:Oligonucleotides, Antisense / Q000494:pharmacology*; D009946:Organothiophosphorus Compounds / Q000494:pharmacology*; D014364:Tryptophan / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D004791:Enzyme Inhibitors; D016376:Oligonucleotides, Antisense; D009946:Organothiophosphorus Compounds; D014364:Tryptophan; D019363:Cytochrome P-450 CYP1A1