title: Sinularin induces DNA damage, G2/M phase arrest, and apoptosis in human hepatocellular carcinoma cells.
abstract: BACKGROUND
  Sinularin isolated from the cultured soft coral Sinularia flexibilis has been reported to exert potent cytotoxic effects against particular types of cancer. This study was carried out to investigate the cytotoxic effects in sinularin-treated human hepatocellular carcinoma cells, HepG2, and to subsequently explore the underlying molecular mechanisms.
  
  
  METHODS
  TheMTT (3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyl- tetrazolium bromide) method was used to evaluate the cytotoxicity of sinularin on HepG2 and Hep3B cell lines. Furthermore, the cell cycle distribution assay, apoptosis assay, and western blot analysis in vitro were used to explore the possible mechanisms of action.
  
  
  RESULTS
  From the results of our study, cell viability was obviously inhibited by sinularin in a dose-dependent manner. In addition, our results suggested that sinularin triggered DNA damage and subsequently induced cell cycle G2/M arrest associated with up-regulation of p-ATM (Ser(1981)), p-Chk2 (Tyr(68)), p-cdc2 (Tyr(15)), and p53 coupled with increased expression of downstream proteins p21 and down-regulation of p-cdc25 (Ser(216)). Moreover, the results of the apoptosis assay and western blot analysis indicated that the cytotoxic activity could be related to mitochondrial apoptosis, characterized by decrease of Bcl-2 expression, disruption of mitochondrial membrane potential, and sequential activation of caspases and Poly (ADP-ribose) polymerase (PARP).
  
  
  CONCLUSIONS
  This study reveals for the first time the anti-HCC activities of sinularin, the active compound isolated from the cultured soft coral Sinularia flexibilis. We believe that our results warrant further evaluation of sinularin as a new anti-HCC chemotherapeutic agent.
authors.affiliation: Institute of Bioinformatics and Structural Biology and Department of Medical Sciences, National Tsing Hua University, Hsinchu, Taiwan.
authors.forename: Ting-Wen
authors.initials: TW
authors.lastname: Chung
authors.affiliation: Ph.D. Program in Medical Biotechnology, National Chung Hsing University, Taichung, Taiwan.|SRI international, Harrisonburg, VA, USA.
authors.forename: Shih-Chao
authors.initials: SC
authors.lastname: Lin
authors.affiliation: Taiwan Coral Research Center, National Museum of Marine Biology & Aquarium, Pingtung, Taiwan.
authors.forename: Jui-Hsin
authors.initials: JH
authors.lastname: Su
authors.affiliation: Department of Food Science, National Pingtung University of Science and Technology, Pingtung, Taiwan.
authors.forename: Yu-Kuo
authors.initials: YK
authors.lastname: Chen
authors.affiliation: Institute of Biomedical Science, National Chung-Hsing University, Taichung, Taiwan. evanlinncku@gmail.com.|Department of Biotechnology, Asia University, Taichung, Taiwan. evanlinncku@gmail.com.|Department of Medical Research, China Medical University Hospital, Taichung, Taiwan. evanlinncku@gmail.com.
authors.forename: Chi-Chien
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Institute of Bioinformatics and Structural Biology and Department of Medical Sciences, National Tsing Hua University, Hsinchu, Taiwan. hlchan@life.nthu.edu.tw.
authors.forename: Hong-Lin
authors.initials: HL
authors.lastname: Chan
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy*; D002453:Cell Cycle / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects*; D004224:Diterpenes / Q000494:pharmacology*; D016195:G2 Phase / Q000187:drug effects; D056945:Hep G2 Cells; D006575:Heterocyclic Compounds, 3-Ring / Q000494:pharmacology*; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D004224:Diterpenes; D006575:Heterocyclic Compounds, 3-Ring; C574383:sinularin
keywords: Apoptosis; DNA damage; G2/M; Hepatocellular carcinoma; Sinularia flexibilis; Sinularin