['To investigate the effect of sodium valproate, a histone deacetylase inhibitor, on the cytotoxicity of doxorubicin in breast cancer cells.', '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.', '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).'] Does [ Sodium valproate enhance doxorubicin cytotoxicity in breast cancer cells in vitro ]?