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. 2014 Mar 19;9(3):e92737. doi: 10.1371/journal.pone.0092737

Figure 5. The PI3K stimulatory activity present in human serum can be evaluated using the MCF-7/B2 cells.

Figure 5

(A, B) MCF-7/B2 cells were starved overnight in culture medium containing only 0.1% FBS. Cells were then stimulated with PBS containing 0%, 1%, 2%, 5% or 10% human serum that had been previously heated or not at 95°C during 1 h, and light emission acquisition started immediately. (A) A typical real-time BRET experiment is shown. (B) Means ± SEM of BRET values at the plateau of 3 to 7 independent experiments are shown. (C) MCF-7/B2 cells were starved overnight in culture medium containing only 0.1% FBS. Cells were then stimulated with 5% human serum previously submitted or not to centrifugation on a centrifugal filter device with a molecular weight cut-off of 3 kDa. A typical real-time BRET experiment (left panel) and means ± SEM of BRET values at the plateau (right panel) are shown (n = 3). (D) MCF-7/B2 cells were starved overnight in culture medium containing only 0.1% FBS. Cells were then stimulated with 5% human serum that had been pre-incubated for 1 h in presence of 50 μM IGFBP1. A typical real-time BRET experiment (left panel) and means ± SEM of BRET values at the plateau (right panel) are shown (n = 3). Statistical analysis was performed using ANOVA followed by Tukey’s test. *, P<0.05; **, P<0.01; ***, P<0.001; NS, Non significant.