title: Comparative properties of the nuclear aryl hydrocarbon (Ah) receptor complex from several human cell lines.
abstract: The aryl hydrocarbon (Ah) responsiveness of the T-47D, Hep G2, LS180, MCF-7, A431, C-4II and MDA-MB-231 human cancer cell lines was determined by the induction of CYP1A1 mRNA levels and ethoxyresorufin O-deethylase activity. With the exception of teh MDA-MB-231 breast cancer cell line, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) significantly induced CYP1A1 mRNA levels and ethoxyresorufin O-deethylase activity in the remaining six cell lines and, based on their EC50 values, for ethoxyresorufin O-deethylase induction, their Ah responsiveness followed the order T-47D > C-4II > MCF-7 > LS180 > HEP G2 > A431. In contrast, all the cell lines expressed the nuclear Ah receptor complex (167.1-24.5 fmol/mg protein) which bound to a 32P-labeled consensus dioxin responsive element (DRE) in a gel mobility shift assay. The results of gel permeation chromatography a sucrose density gradient centrifugation studies showed that the calculated Mr values for the nuclear Ah receptor complex varied from 175 kDa (MDA-MB-231 cells) to 221 kDa and the apparent molecular weight of the nuclear Ah receptor complex cross-linked to a bromodeoxyuridine-substituted DRE was 200 kDa. The data show that the molecular properties and levels of the nuclear Ah receptor complex from seven different human cancer cell lines do not predict Ah responsiveness.
authors.affiliation: Department on Veterinary Physiology and Pharmacology, Texas A&M University, College Station 77843-4466, USA.
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: J S
authors.initials: JS
authors.lastname: Thomsen
authors.forename: M
authors.initials: M
authors.lastname: Santostefano
authors.forename: R
authors.initials: R
authors.lastname: Rosengren
authors.forename: S
authors.initials: S
authors.lastname: Safe
authors.forename: G H
authors.initials: GH
authors.lastname: Perdew
mesh_terms: D000345:Affinity Labels; D001483:Base Sequence; D015152:Blotting, Northern; D002460:Cell Line; D002467:Cell Nucleus; D002499:Centrifugation, Density Gradient; D002850:Chromatography, Gel; D019363:Cytochrome P-450 CYP1A1; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000235:genetics; D004251:DNA Transposable Elements; D004147:Dioxins / Q000494:pharmacology; D004790:Enzyme Induction; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010088:Oxidoreductases / Q000096:biosynthesis / Q000235:genetics; D000072317:Polychlorinated Dibenzodioxins / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D018336:Receptors, Aryl Hydrocarbon / Q000737:chemistry / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D000345:Affinity Labels; D004251:DNA Transposable Elements; D004147:Dioxins; D000072317:Polychlorinated Dibenzodioxins; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; C056902:2-iodo-7,8-dibromodibenzo-1,4-dioxin; D003577:Cytochrome P-450 Enzyme System; D010088:Oxidoreductases; D019363:Cytochrome P-450 CYP1A1