title: Xanthohumol induces apoptosis and S phase cell cycle arrest in A549 non-small cell lung cancer cells.
abstract: BACKGROUND
  Xanthohumol, a major prenylated chalcone found in female hop plant, Humulus lupulus, was reported to have various chemopreventive and anti-cancer properties. However, its apoptotic effect on human alveolar adenocarcinoma cell line (A549) of non-small cell lung cancer (NSCLC) was unknown.
  
  
  OBJECTIVE
  This study aimed to investigate the effects of xanthohumol on apoptosis in A549 human NSCLC cells.
  
  
  METHODS
  A549 cell proliferation was determined by sulforhodamine B assay. Morphological changes of the cells were studied via phase contrast and fluorescent microscopy. Induction of apoptosis was assessed by Annexin-V fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI) staining, DNA fragmentation (TUNEL) assay mitochondrial membrane potential assay, cell cycle analysis, and caspase activity studies.
  
  
  RESULTS
  Xanthohumol was found to decrease cell proliferation in A549 cells but had relatively low cytotoxicity on normal human lung fibroblast cell line (MRC-5). Typical cellular and nuclear apoptotic features were also observed in A549 cells treated with xanthohumol. Onset of apoptosis in A549 cells was further confirmed by externalization of phosphatidylserine, changes in mitochondrial membrane potential, and DNA fragmentation in the cells after treatment. Xanthohumol induced accumulation of cells in sub G1 and S phase based on cell cycle analysis and also increased the activities of caspase-3, -8, and -9.
  
  
  CONCLUSIONS
  This work suggests that xanthohumol as an apoptosis inducer, may be a potent therapeutic compound for NSCLC.
authors.affiliation: Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Wai Kuan
authors.initials: WK
authors.lastname: Yong
authors.affiliation: Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Yen Fong
authors.initials: YF
authors.lastname: Ho
authors.affiliation: Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Sri Nurestri Abd
authors.initials: SN
authors.lastname: Malek
keywords: Human alveolar adenocarcinoma cell line; apoptosis; cell cycle; lung cancer; xanthohumol