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. 2013 Mar 19;8(3):e59323. doi: 10.1371/journal.pone.0059323

Figure 3. IGFBP-2 and -3, but not IGFBP-4 and -6, increase intracellular calcium concentrations by a pertussis toxin-sensitive signaling pathway in MCF-7 cells.

Figure 3

MCF-7 cells cultured on glass coverslips were treated with 200 ng.mL-1 pertussis toxin (PTX) for 16 h at 37°C and were incubated with Fura-2/AM. A. After background recording for 40 seconds to determine basal intracellular calcium concentrations as described in Methods, cells were incubated with 20 nM IGFBP-6, then with IGFBP-3 (20 nM) and then with thapsigargin (Tp) (1 µM). The results of a typical experiment are shown in which the whole field (red line) was analysed and intracellular calcium quantified. The slides from left to right show representative views of the cells (a) before addition of IGFBP-6, (b) after addition of IGFBP-6, (c) after addition of IGFBP-3, and (d) after addition of thapsigargin. The results presented are representative of 4 independent experiments. B and C. Same experiments as in panel A excepted that cells were incubated with either 20 nM IGFBP-2 (panel B) or 20 nM IGFBP-4 (panel C). The results of a typical experiment are shown in which the whole field (red line) was analysed and intracellular calcium quantified. Slides show representative views of the cells after addition of IGFBP-2 or -4, respectively. Results presented are representative of 4 independent experiments.