title: Dual effects of silymarin on nasopharyngeal carcinoma cells (NPC-TW01).
abstract: BACKGROUND
  Silymarin is an active component from the seeds of Silybum marianum and is widely used as a hepatic protection agent. Apoptosis induced by silymarin has been mentioned in cervical cancer cells. However, silymarin shows dual effects on tumor cells: cytostatic action at a low dose and cytotoxic action at higher dose. Thus, in the present study, we focused on low-dosing of silymarin in nasopharyngeal carcinoma cells, NPC-TW01 (TW01).
  
  
  METHODS
  Cell viability assay was used to screen the effect of silymarin in TW01 cells. Western blot analysis was used to identify the expressions of antioxidant enzymes and anti-/proapoptotic proteins. Fluorescent dyes are employed to detect the content of reactive oxygen species (ROS) and cell apoptosis.
  
  
  RESULTS
  Treatment of TW01 cells with silymarin at a low dose (80 µmol/l) resulted in a significant increase of antioxidant enzymes. Silymarin increased the expressions of superoxide dismutase 1, catalase, and glutathione peroxidase. Consequently, the cell apoptosis was reduced markedly. An increase of Bcl-2 expression and a decrease of activated caspase-3 or apoptosis-inducing factor (AIF) were observed in TW01 cells at a low dose (80 µmol/l) treatment.
  
  
  CONCLUSIONS
  Silymarin at a low dose can induce cytostatic effect on TW01 cells mainly through an increase of antioxidant-like action. Thus, silymarin should be applied carefully to patients with nasopharyngeal carcinoma.
authors.affiliation: Institute of Pharmacology, National Yang-Ming University, Taipei City, Taiwan.
authors.forename: Chin-Hui
authors.initials: CH
authors.lastname: Su
authors.forename: Li-Jen
authors.initials: LJ
authors.lastname: Chen
authors.forename: Jyh Fei
authors.initials: JF
authors.lastname: Liao
authors.forename: Juei-Tang
authors.initials: JT
authors.lastname: Cheng
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D051033:Apoptosis Inducing Factor / Q000235:genetics; D002277:Carcinoma; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D019254:Genes, bcl-2 / Q000235:genetics; D006801:Humans; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy; D010088:Oxidoreductases / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000032:analysis; D012838:Silymarin / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D051033:Apoptosis Inducing Factor; D017382:Reactive Oxygen Species; D012838:Silymarin; D010088:Oxidoreductases