Figure 2: Caspase activation in response to 1, 25-D3 and IGFBP-3. MCF-7 and MCF-7/VDR cells were treated with 100 nM 1, 25-D3 or 0.1% ethanol as vehicle control for 5 days (left hand panel) or 100 nM IGFBP-3 for 3 days. Control cells received an equal volume of PBS diluent (right-hand panel). Whole cell extracts were prepared and analysed by immunoblotting using specific antibodies of interest and β-actin was used as a loading control. Data shown are representative of three identical experiments.