title: Disulfiram modulated ROS-MAPK and NFκB pathways and targeted breast cancer cells with cancer stem cell-like properties.
abstract: BACKGROUND
  Previous studies indicate that disulfiram (DS), an anti-alcoholism drug, is cytotoxic to cancer cell lines and reverses anticancer drug resistance. Cancer stem cells (CSCs) are the major cause of chemoresistance leading to the failure of cancer chemotherapy. This study intended to examine the effect of DS on breast cancer stem cells (BCSCs).
  
  
  METHODS
  The effect of DS on BC cell lines and BCSCs was determined by MTT, western blot, CSCs culture and CSCs marker analysis.
  
  
  RESULTS
  Disulfiram was highly toxic to BC cell lines in vitro in a copper (Cu)-dependent manner. In Cu-containing medium (1 μM), the IC(50) concentrations of DS in BC cell lines were 200-500 nM. Disulfiram/copper significantly enhanced (3.7-15.5-fold) cytotoxicity of paclitaxel (PAC). Combination index isobologram analysis demonstrated a synergistic effect between DS/Cu and PAC. The increased Bax and Bcl2 protein expression ratio indicated that intrinsic apoptotic pathway may be involved in DS/Cu-induced apoptosis. Clonogenic assay showed DS/Cu-inhibited clonogenicity of BC cells. Mammosphere formation and the ALDH1(+VE) and CD24(Low)/CD44(High) CSCs population in mammospheres were significantly inhibited by exposure to DS/Cu for 24 h. Disulfiram/copper induced reactive oxygen species (ROS) generation and activated its downstream apoptosis-related cJun N-terminal kinase and p38 MAPK pathways. Meanwhile, the constitutive NFκB activity in BC cell lines was inhibited by DS/Cu.
  
  
  CONCLUSIONS
  Disulfiram/copper inhibited BCSCs and enhanced cytotoxicity of PAC in BC cell lines. This may be caused by simultaneous induction of ROS and inhibition of NFκB.
authors.affiliation: Research Institute in Healthcare Science, School of Applied Sciences, University of Wolverhampton, Wolverhampton WV1 1LY, UK.
authors.forename: N C
authors.initials: NC
authors.lastname: Yip
authors.forename: I S
authors.initials: IS
authors.lastname: Fombon
authors.forename: P
authors.initials: P
authors.lastname: Liu
authors.forename: S
authors.initials: S
authors.lastname: Brown
authors.forename: V
authors.initials: V
authors.lastname: Kannappan
authors.forename: A L
authors.initials: AL
authors.lastname: Armesilla
authors.forename: B
authors.initials: B
authors.lastname: Xu
authors.forename: J
authors.initials: J
authors.lastname: Cassidy
authors.forename: J L
authors.initials: JL
authors.lastname: Darling
authors.forename: W
authors.initials: W
authors.lastname: Wang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D003300:Copper / Q000494:pharmacology; D004221:Disulfiram / Q000494:pharmacology*; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D006801:Humans; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D014411:Neoplastic Stem Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D003300:Copper; D020928:Mitogen-Activated Protein Kinases; D004221:Disulfiram