title: The nuclear receptor constitutive active/androstane receptor arrests DNA-damaged human hepatocellular carcinoma Huh7 cells at the G2/M phase.
abstract: Here, we have demonstrated that xenobiotic activation of the nuclear receptor (CAR, NR1I3) can result in arresting DNA-damaged human hepatocellular carcinoma Huh7 cells at the G2/M phase. Huh7 cells over-expressing CAR were either treated with dimethyl sulfoxide, the CAR activator TCPOBOP (1,4-bis[2-(3,5-dichloropyridyloxy)]benzene; androstenol, 16,(5α)-androsten-3α-OL), or repressor androstenol; these treatments were then followed by adriamycin treatment to damage DNA. FACS analysis revealed that CAR-activation by TCPOBOP increased the rate of arrested Huh7 cells at the G2/M phase (4N DNA content) after DNA damage by adriamycin. This increase correlated with the increase of cell viability in TCPOBOP-treated Huh7 cells, as determined by MTT assays. Real-time polymerase chain reaction analysis determined that, as regulated by CAR, the growth arrest and DNA damage-inducible γ (GADD45γ) and Cyclin G2 genes increased and decreased, respectively, as TCPOBOP increased the number of Huh7 cells arrested at the G2/M phase. Thus, the results suggest that CAR regulates cell cycle, increasing G2/M arrest, and delaying the death of DNA-damaged cells.
authors.affiliation: Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kamino
authors.forename: Masahiko
authors.initials: M
authors.lastname: Negishi
mesh_terms: D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000378:metabolism / Q000473:pathology*; D002455:Cell Division; D045744:Cell Line, Tumor; D000090702:Constitutive Androstane Receptor; D004249:DNA Damage; D017931:DNA Primers; D005434:Flow Cytometry; D016195:G2 Phase; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism / Q000473:pathology*; D060888:Real-Time Polymerase Chain Reaction; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology*
chemical_list: D000090702:Constitutive Androstane Receptor; D017931:DNA Primers; C000716327:NR1I3 protein, human; D018160:Receptors, Cytoplasmic and Nuclear