title: Stability of the aryl hydrocarbon receptor and its regulated genes in the low activity variant of Hepa-1 cell line.
abstract: We examined the expression kinetics of some of the aryl hydrocarbon receptor (AhR)-regulated genes in LA1 variant cells compared to wild type (WT) Hepa-1 mouse hepatoma cell lines, and we investigated the stability of AhR protein as a key step in the function of this receptor. Treatment of both cell types with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) resulted in increased CYP1A1 and CYP1B1 mRNA with a subsequent down regulation of AhR. We show here that co-treatment with transcription inhibitor actinomycin D (ActD) has reversed the TCDD-induced depletion of AhR protein in WT. However, the proteolytic degradation of AhR in absence of TCDD was significantly higher in LA1 cells than in WT, and ActD treatment reduced this loss. Induction of CYP1A1 and CYP1B1 mRNA by TCDD in WT cells each exhibited bursts of activity in the initial hour which were about 3-fold greater than in LAI cells. The induced mRNA levels in LA1 exhibited a slow and sustained increase approximating the WT levels by 20h. The induction of two other AhR-regulated genes also showed comparable turnover differences between the two types of cell. Thus, altered regulation of the AhR responsive genes in LA1 may result from a difference in AhR stability.
authors: Department of Biochemistry and Cancer Biology, Meharry Medical College, 1005 D.B. Todd Blvd., Nashville, TN 37208, USA.
authors: Andria
authors: A
authors: Humphrey-Johnson
authors: Department of Biochemistry and Cancer Biology, Meharry Medical College, 1005 D.B. Todd Blvd., Nashville, TN 37208, USA.
authors: Rawia
authors: R
authors: Abukalam
authors: Department of Biochemistry and Cancer Biology, Meharry Medical College, 1005 D.B. Todd Blvd., Nashville, TN 37208, USA. Electronic address: seltom@mmc.edu.
authors: Sakina E
authors: SE
authors: Eltom
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D019363:Cytochrome P-450 CYP1A1 / Q000096:biosynthesis; D065633:Cytochrome P-450 CYP1B1 / Q000096:biosynthesis; D003609:Dactinomycin / Q000494:pharmacology; D004785:Environmental Pollutants / Q000633:toxicity; D004790:Enzyme Induction / Q000187:drug effects; D005786:Gene Expression Regulation / Q000235:genetics*; D006801:Humans; D007700:Kinetics; D051379:Mice; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics* / Q000378:metabolism*; D014178:Translocation, Genetic
chemical_list: D004785:Environmental Pollutants; D000072317:Polychlorinated Dibenzodioxins; D011500:Protein Synthesis Inhibitors; D018336:Receptors, Aryl Hydrocarbon; D003609:Dactinomycin; D019363:Cytochrome P-450 CYP1A1; D065633:Cytochrome P-450 CYP1B1
keywords: AhR turnover; CYP1A1; Hepa-1 cell line; RNA stability
references: J Biol Chem. 2000 Mar 3;275(9):6153-9
references: 10692406
references: J Biol Chem. 2000 Mar 24;275(12):8432-8
references: 10722677
references: J Biol Chem. 2000 Apr 28;275(17):12676-83
references: 10777561
references: Mol Cell Biol. 2001 Apr;21(7):2594-607
references: 11259606
references: Proc Natl Acad Sci U S A. 1979 Jan;76(1):373-6
references: 106390
references: Annu Rev Pharmacol Toxicol. 1982;22:517-54
references: 6282188
references: Cancer Res. 1982 Dec;42(12):4875-917
references: 6814745
references: J Biol Chem. 1983 Mar 25;258(6):3523-7
references: 6300048
references: J Biol Chem. 1984 Jan 25;259(2):980-5
references: 6319394
references: Mol Pharmacol. 1984 Jul;26(1):117-21
references: 6749129
references: Gene. 1984 Sep;29(3):281-92
references: 6548461
references: Science. 1985 Mar 22;227(4693):1499-502
references: 3856321
references: Nucleic Acids Res. 1985 Mar 11;13(5):1431-42
references: 2987824
references: Mol Cell Biol. 1986 May;6(5):1471-7
references: 3785172
references: J Biol Chem. 1988 Jun 25;263(18):8671-6
references: 3379039
references: J Biol Chem. 1989 Oct 5;264(28):16478-82
references: 2550446
references: Science. 1991 May 17;252(5008):954-8
references: 1852076
references: Biochemistry. 1991 Aug 13;30(32):8041-5
references: 1868078
references: Can J Physiol Pharmacol. 1991 Aug;69(8):1204-10
references: 1664293
references: Proc Natl Acad Sci U S A. 1992 Sep 1;89(17):8185-9
references: 1325649
references: J Biol Chem. 1994 May 27;269(21):14905-11
references: 8195121
references: Mol Cell Biol. 1994 Sep;14(9):5653-60
references: 8065302
references: J Biol Chem. 1994 Dec 16;269(50):31505-9
references: 7989317
references: J Biol Chem. 1995 May 12;270(19):11595-602
references: 7744798
references: J Biol Chem. 1995 May 26;270(21):12697-703
references: 7759522
references: Biochem Pharmacol. 1995 Dec 22;50(12):2057-68
references: 8849333
references: Mol Cell Biol. 1996 May;16(5):2144-50
references: 8628281
references: Mol Pharmacol. 1996 Mar;49(3):391-8
references: 8643077
references: J Biol Chem. 1996 Sep 13;271(37):22746-53
references: 8798449
references: Mol Pharmacol. 1996 Dec;50(6):1454-62
references: 8967965
references: J Biol Chem. 1997 Apr 4;272(14):8878-84
references: 9083006
references: J Biol Chem. 1997 Apr 25;272(17):11452-6
references: 9111057
references: Nat Biotechnol. 1997 Aug;15(8):784-8
references: 9255795
references: Mol Cell Biol. 1998 Feb;18(2):978-88
references: 9447995
references: Carcinogenesis. 1998 Aug;19(8):1437-44
references: 9744540
references: Biochemistry. 1999 Jul 13;38(28):8907-17
references: 10413464
references: J Biol Chem. 1999 Oct 1;274(40):28708-15
references: 10497241
references: Toxicol Lett. 2006 Oct 10;166(2):150-9
references: 16891067
references: Mol Pharmacol. 2006 Nov;70(5):1481-7
references: 16891617
references: Mol Pharmacol. 1999 Mar;55(3):594-604
references: 10051545