title: Regulation of human carbonyl reductase 3 (CBR3; SDR21C2) expression by Nrf2 in cultured cancer cells.
abstract: Carbonyl reduction is a central metabolic process that controls the level of key regulatory molecules as well as xenobiotics. Carbonyl reductase 3 (CBR3; SDR21C2), a member of the short-chain dehydrogenase/reductase (SDR) superfamily, has been poorly characterized so far, and the regulation of its expression is a complete mystery. Here, we show that CBR3 expression is regulated via Nrf2, a key regulator in response to oxidative stress. In human cancer cell lines, CBR3 mRNA was expressed differentially, ranging from very high (A549, lung) to very low (HT-29, colon; HepG2, liver) levels. CBR3 protein was highly expressed in SW-480 (colon) cells but was absent in HCT116 (colon) and HepG2 cells. CBR3 mRNA could be induced in HT-29 cells by Nrf2 agonists [sulforaphane (SUL, 7-fold) and diethyl maleate (DEM, 4-fold)] or hormone receptor ligand Z-guggulsterone (5-fold). Aryl hydrocarbon receptor agonist B[k]F failed to induce CBR3 mRNA after incubation for 8 h but elevated CBR3 levels after 24 h, most likely mediated by B[k]F metabolites that can activate Nrf2 signaling. Inhibition of Nrf2-activating upstream kinase MEK/ERK by PD98059 weakened DEM-mediated induction of CBR3 mRNA. Proteasome inhibitors MG-132 (5 μM) and bortezomib (50 nM) dramatically increased the level of CBR3 mRNA, obviously because of the increase in the level of Nrf2 protein. While siRNA-mediated knockdown of Nrf2 led to a decrease in the level of CBR3 mRNA in A549 cells (30% of control), Keap1 knockdown increased the level of CBR3 mRNA expression in HepG2 (9.3-fold) and HT-29 (2.7-fold) cells. Here, we provide for the first time evidence that human CBR3 is a new member of the Nrf2 gene battery.
authors.affiliation: Institute of Toxicology and Pharmacology for Natural Scientists, University Medical School Schleswig-Holstein, Kiel, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Ebert
authors.forename: Michael
authors.initials: M
authors.lastname: Kisiela
authors.forename: Petra
authors.initials: P
authors.lastname: Malátková
authors.forename: Yasser
authors.initials: Y
authors.lastname: El-Hawari
authors.forename: Edmund
authors.initials: E
authors.lastname: Maser
mesh_terms: D000429:Alcohol Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism; D006224:Cricetinae; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D015870:Gene Expression; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006873:Hydroquinones / Q000494:pharmacology; D007976:Leupeptins / Q000494:pharmacology; D008298:Maleates / Q000494:pharmacology; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000235:genetics; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D061988:Proteasome Inhibitors; D012333:RNA, Messenger / Q000235:genetics; D014162:Transfection
chemical_list: D004791:Enzyme Inhibitors; D005419:Flavonoids; D006873:Hydroquinones; D007976:Leupeptins; D008298:Maleates; D051267:NF-E2-Related Factor 2; D061988:Proteasome Inhibitors; D012333:RNA, Messenger; C018855:2-tert-butylhydroquinone; D000429:Alcohol Oxidoreductases; C531130:CBR3 protein, human; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human; C014476:diethyl maleate; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one