Figure 4

Ets-1 mediates the NO-induced aggressive basal-like phenotype. (a) Representative western blots of Ets-1, P-cadherin, S100A8, αβ-crystallin, cathepsin B (CTSB) and actin expression in MDA-MB-468 cells transfected with either control or Ets-1 siRNA and treated with DETANO. (b) Densitometic analyses of proteins described in (a) relative to untreated control plasmid cells. (c) IL-8 production from MDA-MB-468 cells transfected with either control or Ets-1 siRNA and treated with DETANO. Significance (**P < 0.01) was determined by t-test. (d) Proliferation of MDA-MB-468 cells transfected with control or Ets-1 siRNA and treated with DETANO in serum-free RPMI. Data represent the fold change compared to untreated, control siRNA cells. Significance compared to control siRNA transfected cells was determined by t-test (**P < 0.01). (Inset: Western blot of Ets-1 expression compared to actin in transfected MDA-MB-231 cells.) (e) CTSB activity in cells transfected with control or Ets-1 siRNA and treated with DETANO. Relative fluorescence units (RFU) were normalized to µg of total protein ± SD. Significance (*P < 0.05, **P < 0.01) was determined by t-test. DETANO, diethlylenetriamine NONOate; Ets-1, erythroblastosis virus E26 oncogene homolog 1; SD, standard deviation.