title: RNA Interference Protects Against 5-Lipoxygenase-Induced Cocarcinogen, Benzidine, Oxidation and Cytotoxicity in Human Tracheobronchial Epithelial Cells.
abstract: Lipoxygenase (LOX)-catalyzed cooxidation of the human carcinogen benzidine (BZD) has been shown in in vitro enzyme systems. This study aimed to determine whether BZD could be activated by arachidonate 5-lipoxygenase (ALOX5) in the human tracheobronchial epithelial cells (HBECs) using RNA interference strategy and a 5-LOX-specific inhibitor, AA861. We show that the soybean LOX catalyzed the cooxidation of BZD, generating BZD diimine. Benzidine induced expression of ALOX5 messenger RNA and 5-LOX protein in HBECs, and significantly decreased cell proliferation, but enhanced DNA damage and apoptosis in HBECs which were significantly inhibited by lentiviral-mediated small hairpin RNA-knockdown of ALOX5 and by AA861. Thus, BZD could upregulate the expression of ALOX5 in HBECs, while inhibition of the protein or gene expression or enzyme activity could prevent BZD-induced cytotoxicity and DNA damage in HBECs, which might be caused by the 5-LOX-catalyzed oxidative activation of BZD.
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Central South University, Changsha, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Dalang Institute of Health Supervision in Baoan District, Shenzhen, Guangdong, China.
authors.forename: Qingping
authors.initials: Q
authors.lastname: Tan
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Central South University, Changsha, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Department of Control Effect Evaluation, Hunan Provincial Institute for Labor Hygiene and Occupational Diseases, Changsha, China.
authors.forename: Hongxiang
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Central South University, Changsha, China.
authors.forename: Minru
authors.initials: M
authors.lastname: Xiong
authors.affiliation: Department of Occupational and Environmental Health, School of Public Health, Central South University, Changsha, China jiananhu@csu.edu.cn.
authors.forename: Jianan
authors.initials: J
authors.lastname: Hu
mesh_terms: D065767:Activation, Metabolic; D017209:Apoptosis / Q000187:drug effects*; D001094:Arachidonate 5-Lipoxygenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001560:Benzidines / Q000378:metabolism / Q000633:toxicity*; D016227:Benzoquinones / Q000494:pharmacology; D001980:Bronchi; D002273:Carcinogens / Q000378:metabolism / Q000633:toxicity*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D003043:Cocarcinogenesis / Q000139:chemically induced*; D004790:Enzyme Induction / Q000187:drug effects; D057809:HEK293 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D008084:Lipoxygenase / Q000378:metabolism; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology; D010084:Oxidation-Reduction; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D020545:Respiratory Mucosa / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D014132:Trachea
chemical_list: D001560:Benzidines; D016227:Benzoquinones; D002273:Carcinogens; D016859:Lipoxygenase Inhibitors; D012333:RNA, Messenger; C029876:benzidine; C043382:benzidine-4,4'-diimine; C036837:2,3,5-trimethyl-6-(12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone; D006861:Hydrogen Peroxide; C101084:lipoxygenase L-1; D008084:Lipoxygenase; D001094:Arachidonate 5-Lipoxygenase; C583212:ALOX5 protein, human
keywords: 5-lipoxygenase; DNA damage; apoptosis; benzidine co-oxidation; human respiratory tract epithelial cells; lentivirus; shRNA