title: Psoralidin induced reactive oxygen species (ROS)-dependent DNA damage and protective autophagy mediated by NOX4 in breast cancer cells.
abstract: BACKGROUND
  Psoralidin (PSO), a natural phenolic coumarin, was reported to have anti-cancer activities. PSO induced reactive oxygen species (ROS) generation in cancer cells. The role of ROS in its anti-cancer effect remains unclear.
  
  
  OBJECTIVE
  This study was designed to investigate the potential roles of ROS in PSO-induced anti-cancer effect in MCF-7 breast cancer cells.
  
  
  METHODS
  Effect of PSO on cancer cell proliferation was determined by MTT assay. Comet assay was used to determine DNA damage. Protein expression was detected by Western blotting. Autophagic vacuoles were detected by monodansylcadaverine (MDC) staining. ROS generation was measured by fluorescent probe. NOX4 localization was determined by immunofluorescence staining.
  
  
  RESULTS
  PSO treatment caused proliferation inhibition in time- and dose- dependent manners, which was partially reversed by N-acetyl cysteine (NAC) and diphenyleneiodonium (DPI). PSO induced DNA damage and increased protein expression of γ-H2AX, phosphorylation of ATM, ATR, Chk1, and Chk2. PSO induced autophagy as evidenced by the accumulation of autophagic vacuoles and alterations of autophagic protein expression. PSO-induced cell death was enhanced by autophagy inhibitor chloroquine (CQ). Furthermore, PSO treatment induced ROS formation, which was reversed by NAC or DPI pretreatment. The expression of NOX4 was significantly enhanced by PSO. Both NAC and DPI could reverse PSO-induced DNA damage and autophagic responses. In addition, silencing NOX4 by siRNA inhibited PSO-induced ROS generation, DNA damage, and autophagy.
  
  
  CONCLUSIONS
  Taken together, these results showed that PSO induced DNA damage and protective autophagy mediated by ROS generation in a NOX4-dependent manner in MCF-7 cells.
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China.
authors.forename: Guowen
authors.initials: G
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Niu
authors.affiliation: Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong, China.
authors.forename: Dik-Lung
authors.initials: DL
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China.
authors.forename: Chung-Hang
authors.initials: CH
authors.lastname: Leung
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China.
authors.forename: Yitao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China. Electronic address: jinjian.lu@163.com.
authors.forename: Jin-Jian
authors.initials: JJ
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macao, China. Electronic address: xpchen@umac.mo.
authors.forename: Xiuping
authors.initials: X
authors.lastname: Chen
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000633:toxicity*; D017209:Apoptosis / Q000187:drug effects; D001343:Autophagy / Q000187:drug effects*; D001572:Benzofurans / Q000633:toxicity*; D001943:Breast Neoplasms / Q000235:genetics*; D002103:Cadaverine / Q000031:analogs & derivatives; D049109:Cell Proliferation / Q000187:drug effects; D003374:Coumarins / Q000633:toxicity*; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D005260:Female; D005456:Fluorescent Dyes; D020868:Gene Silencing; D006801:Humans; D061986:MCF-7 Cells; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D026361:Reactive Nitrogen Species
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D001572:Benzofurans; D003374:Coumarins; D005456:Fluorescent Dyes; D034741:RNA, Small Interfering; D026361:Reactive Nitrogen Species; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human; C102768:psoralidin; C008542:monodansylcadaverine; D002103:Cadaverine
keywords: Autophagy; DNA damage; NOX4; Psoralidin; ROS