title: [Sodium valproate enhances doxorubicin cytotoxicity in breast cancer cells in vitro].
abstract: OBJECTIVE
  To investigate the effect of sodium valproate, a histone deacetylase inhibitor, on the cytotoxicity of doxorubicin in breast cancer cells.
  
  
  METHODS
  Western blotting was used to assess Cx43 protein expression in breast cancer Hs578T cells exposed to doxorubicin and sodium valproate. MTT assay was used to determine the cytotoxicity of doxorubicin; annexin V/PI double staining and Hochest 33258 fluorescence staining were employed to detect doxorubicin-induced early and late apoptosis, respectively.
  
  
  RESULTS
  Western blotting showed that sodium valproate significantly increased Cx43 protein expression in Hs578T cells (P/0.01). The cells exposed to both sodium valproate and doxorubicin showed significantly lowered cell viability compared with the cells exposed to doxorubicin alone (P/0.01). Exposure to both sodium valproate and doxorubicin resulted in significantly increased early and late cell apoptosis rate compared with doxorubicin treatment alone (P/0.01).
  
  
  CONCLUSIONS
  sodium valproate can significantly enhance the cytotoxicity of doxorubicin and increase doxorubicin-induced apoptosis in breast cancer cells in vitro possibly by enhancing the gap junction function.
authors.affiliation: Department of Pharmacology, Faculty of Pharmacy, Bengbu Medical College, Bengbu 233030, China.E-mail: bbmctxh@126.com.
authors.forename: Xu-Hui
authors.initials: XH
authors.lastname: Tong
authors.forename: Chao
authors.initials: C
authors.lastname: Zheng
authors.forename: Guo-Jun
authors.initials: GJ
authors.lastname: Jiang
authors.forename: Shu-Ying
authors.initials: SY
authors.lastname: Dong
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D001943:Breast Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D018031:Connexin 43 / Q000378:metabolism; D004317:Doxorubicin / Q000494:pharmacology*; D004357:Drug Synergism; D017629:Gap Junctions; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology; D006801:Humans; D014635:Valproic Acid / Q000494:pharmacology*
chemical_list: D018031:Connexin 43; D056572:Histone Deacetylase Inhibitors; D014635:Valproic Acid; D004317:Doxorubicin