Flo-1 cells were stably-transfected with an eGFP-tagged empty vector or SELENBP1-containing plasmid. The transfection efficiency was estimated to be 60% to 70%. A, Immunoblot analysis of SELENBP1 protein expression in geneticin-selected clones in the presence or absence of 2.5 μM MSA. β-actin served as a loading control. B, Overexpression of SELENBP1 potentiated the anti-proliferative effect of MSA (2.5μM) and NaS (10 μM) particularly during treatment with CDDP (10 μg/mL) as determined by WST-1 assays. Cells were treated with either MSA or NaS for 72 hrs, and CDDP for 24 hrs. WST-1 data endpoints represent four independent wells. C, Small but statistically significant increases in apoptosis were observed by flow cytometry in SELENBP1-expressing cells treated with 2.5 μM MSA, 20 μg/mL CDDP or both agents, but were not discernible by D, immunoblot analysis of PARP cleavage. β-actin was used as a loading control. Each flow cytometry data point represents 3 independently-treated wells. All data were confirmed in repeated experiments. *, p<0.05; †, p<0.01; ‡, p<0.005; Student's t-test vs. empty vector control.