Figure 4: Differential modulation of IGF-induced Akt phosphorylation in response to 1, 25-D3 and IGFBP-3 treatment in MCF-7 and MCF-7/VDR cells. (a) MCF-7 and MCF-7/VDR cells were treated with 100 nM 1, 25-D3 or 30 nM IGF-I, alone or in combination, in serum-free medium. Cells were also treated with 100 nM IGFBP-3 alone or in combination with 30 nM IGF-I in serum-free medium. After 5 days of treatment, whole cell extracts were prepared and analysed by immunoblotting for total-Akt (T-Akt) and phospho-Akt (P-Akt). (b) Densitometric analysis of immunoblots was performed using GS-800 Calibrated Densitometer (Bio-Rad UK). Data shown are representative of three identical experiments. Means of 3 separated experiments are shown. * and ** are statistically significant.