Role of Insulin-Like Growth Factor Binding Protein-3 in 1, 25-Dihydroxyvitamin-D₃-Induced Breast Cancer Cell Apoptosis

Figure 3

Modulation of IGF-induced Akt phosphorylation in response to 1, 25-D₃ treatment in MCF-7 and MCF-7/VD^R cells. (a) MCF-7 and MCF-7/VD^R 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 cultured in medium supplemented with 2% serum as a control. After 6 days of treatment, cell viability was estimated by neutral red assay. *𝑃<0.05 and **𝑃<0.001 are statistically significant compared to control. Means of 3 separated experiments are shown (𝑛=12). (b) (i) MCF-7 and MCF-7/VD^R cells were treated with 100 nM 1, 25-D₃ or 30 nM IGF-I, alone or in combination, in serum-free medium. After 5 days of treatment, whole cell extracts were prepared and analysed on a phospho-MAPK antibody array (R&D Systems, UK) following manufacturer’s instruction. (ii) Densitometric analysis of Akt phosphorylation. Data shown are means of 3 replicates, significantly different from parental cells. **𝑃<0.001.

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