title: The apoptotic effects of silibinin on MDA-MB-231 and MCF-7 human breast carcinoma cells.
abstract: BACKGROUND
  Silibinin is a bioactive flavonolignan extracted from milk thistle, known as Silybum marianum. Silibinin exerts strong antiproliferative, proapoptotic, and anti-inflammatory effects. Many studies have shown that silibinin inhibits experimentally induced malignancies of the liver, prostate, skin, and colon as well as promotes inhibition of the proliferation of cancer cell lines in vitro. This study aimed to investigate the effects of silibinin on the human breast carcinoma cell lines MDA-MB-231 and MCF-7 in monolayer and spheroid cultures.
  
  
  METHODS
  The MDA-MB-231 and MCF-7 cell lines were cultured in both monolayer and spheroid cultures. Cells were treated with silibinin at 24, 48, and 72 h of incubation. The 5-bromo-2'-deoxyuridine labeling index was used to determine the cells of the synthesis phase. Poly-ADP-ribose-polimerase immunohistochemical staining and the terminal deoxynucleotidyl transferase dUTP nick and labeling assay were used to determine the death of cells in both the monolayer and spheroid cultures.
  
  
  RESULTS
  An half maximal inhibitory concentration dose of silibinin in MDA-MB-231 and MCF-7 cells was 100 µM/mL at 24, 48, and 72 h of incubation. Terminal deoxynucleotidyl transferase dUTP nick and labeling positive cells and active poly-ADP-ribose-polimerase were detected after treatment with silibinin in both the monolayer and spheroid cultures. The dead cell count was higher in the MDA-MB-231 and MCF-7 cell lines with silibinin applied than in the controls.
  
  
  CONCLUSIONS
  Our study demonstrated that silibinin applications enhanced terminal deoxynucleotidyl transferase dUTP nick and labeling positive cells and active poly-ADP-ribose-polimerase in comparison to the control in both the monolayer and spheroid cultures.
authors.affiliation: 1 Süleyman Demirel University, Faculty of Medicine, Department of Histology and Embryology, Isparta, Turkey.
authors.forename: D
authors.initials: D
authors.lastname: Bayram
authors.affiliation: 2 Muğla Sitki Koçman University, Faculty of Medicine, Department of Medical Biology, Muğla, Turkey.
authors.forename: E S
authors.initials: ES
authors.lastname: Çetin
authors.affiliation: 3 Muğla Sitki Koçman University, Faculty of Medicine, Department of Medical Genetic, Muğla, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Kara
authors.affiliation: 1 Süleyman Demirel University, Faculty of Medicine, Department of Histology and Embryology, Isparta, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Özgöçmen
authors.affiliation: 1 Süleyman Demirel University, Faculty of Medicine, Department of Histology and Embryology, Isparta, Turkey.
authors.forename: I A
authors.initials: IA
authors.lastname: Candan
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000378:metabolism; D045744:Cell Line, Tumor; D006801:Humans; D020287:In Situ Nick-End Labeling; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D000077385:Silybin; D012838:Silymarin / Q000494:pharmacology*; D018874:Spheroids, Cellular / Q000187:drug effects / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D012838:Silymarin; D000077385:Silybin; D011065:Poly(ADP-ribose) Polymerases
keywords: Apoptosis; breast cancer; silibinin