title: 9,10-phenanthrenequinone induces monocytic differentiation of U937 cells through regulating expression of aldo-keto reductase 1C3.
abstract: Persistent inhalation of diesel exhaust particles results in damaged lung cells through formation of reactive oxygen species (ROS), but the details of the toxicity mechanism against monocytes are poorly understood. In this study, we used human promyelomonocytic U937 cells as surrogates of monocytes and investigated the toxicity mechanism initiated by exposure to 9,10-phenanthrenequinone (9,10-PQ), a major quinone component in diesel exhaust particles. A 24-h incubation with 9,10-PQ provoked apoptotic cell death, which was due to signaling through the enhanced ROS generation and concomitant caspase activation. Flow cytometric analyses of U937 cells after long-term exposure to 9,10-PQ revealed induction of differentiation that was evidenced by increasing expression of CD11b/CD18, a cell-surface marker for monocytic differentiation into macrophages. The 9,10-PQ-induced differentiation was significantly abolished by ROS inhibitors, suggesting that ROS generation contributes to cell differentiation. The 9,10-PQ treatment increased the expression of aldo-keto reductase (AKR) 1C3, which reached a peak at 1 to 2 d post-treatment and then declined. The bell-shaped curve of the AKR1C3 expression by 9,10-PQ resembled that caused by phorbol 12-myristate 13-acetate, a differentiation inducer. Additionally, the concomitant treatment with tolfenamic acid, a selective AKR1C3 inhibitor, sensitized the differentiation induced by 9,10-PQ. These results suggest that ROS formation during 9,10-PQ treatment acutely leads to apoptosis of U937 cells and the initiation of monocytic differentiation, which proceeds after the provisional overexpression of AKR1C3.
authors.affiliation: Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu, Japan. matsunagat@gifu-pu.ac.jp
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsunaga
authors.forename: Mika
authors.initials: M
authors.lastname: Hosogai
authors.forename: Marina
authors.initials: M
authors.lastname: Arakaki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Endo
authors.forename: Ossama
authors.initials: O
authors.lastname: El-Kabbani
authors.forename: Akira
authors.initials: A
authors.lastname: Hara
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D000074425:Aldo-Keto Reductase Family 1 Member C3; D017209:Apoptosis / Q000187:drug effects; D039481:CD11b Antigen / Q000378:metabolism; D018821:CD18 Antigens / Q000378:metabolism; D002273:Carcinogens / Q000494:pharmacology; D020169:Caspases / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000378:metabolism*; D019570:Inhalation Exposure / Q000009:adverse effects; D008171:Lung Diseases / Q000209:etiology / Q000378:metabolism; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism; D009153:Mutagens / Q000633:toxicity*; D010616:Phenanthrenes / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D020298:U937 Cells; D001335:Vehicle Emissions / Q000633:toxicity*; D062367:ortho-Aminobenzoates / Q000494:pharmacology
chemical_list: D039481:CD11b Antigen; D018821:CD18 Antigens; D002273:Carcinogens; D009153:Mutagens; D010616:Phenanthrenes; D017382:Reactive Oxygen Species; D001335:Vehicle Emissions; D062367:ortho-Aminobenzoates; C009500:tolfenamic acid; C005399:9,10-phenanthrenequinone; D015096:3-Hydroxysteroid Dehydrogenases; D006911:Hydroxyprostaglandin Dehydrogenases; C487341:AKR1C3 protein, human; D000074425:Aldo-Keto Reductase Family 1 Member C3; D020169:Caspases; D013755:Tetradecanoylphorbol Acetate